Merge tag 'mmc-v5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc
[linux-2.6-microblaze.git] / fs / ext4 / inode.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/inode.c
4  *
5  * Copyright (C) 1992, 1993, 1994, 1995
6  * Remy Card (card@masi.ibp.fr)
7  * Laboratoire MASI - Institut Blaise Pascal
8  * Universite Pierre et Marie Curie (Paris VI)
9  *
10  *  from
11  *
12  *  linux/fs/minix/inode.c
13  *
14  *  Copyright (C) 1991, 1992  Linus Torvalds
15  *
16  *  64-bit file support on 64-bit platforms by Jakub Jelinek
17  *      (jj@sunsite.ms.mff.cuni.cz)
18  *
19  *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
20  */
21
22 #include <linux/fs.h>
23 #include <linux/mount.h>
24 #include <linux/time.h>
25 #include <linux/highuid.h>
26 #include <linux/pagemap.h>
27 #include <linux/dax.h>
28 #include <linux/quotaops.h>
29 #include <linux/string.h>
30 #include <linux/buffer_head.h>
31 #include <linux/writeback.h>
32 #include <linux/pagevec.h>
33 #include <linux/mpage.h>
34 #include <linux/namei.h>
35 #include <linux/uio.h>
36 #include <linux/bio.h>
37 #include <linux/workqueue.h>
38 #include <linux/kernel.h>
39 #include <linux/printk.h>
40 #include <linux/slab.h>
41 #include <linux/bitops.h>
42 #include <linux/iomap.h>
43 #include <linux/iversion.h>
44
45 #include "ext4_jbd2.h"
46 #include "xattr.h"
47 #include "acl.h"
48 #include "truncate.h"
49
50 #include <trace/events/ext4.h>
51
52 static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
53                               struct ext4_inode_info *ei)
54 {
55         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
56         __u32 csum;
57         __u16 dummy_csum = 0;
58         int offset = offsetof(struct ext4_inode, i_checksum_lo);
59         unsigned int csum_size = sizeof(dummy_csum);
60
61         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
62         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
63         offset += csum_size;
64         csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
65                            EXT4_GOOD_OLD_INODE_SIZE - offset);
66
67         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
68                 offset = offsetof(struct ext4_inode, i_checksum_hi);
69                 csum = ext4_chksum(sbi, csum, (__u8 *)raw +
70                                    EXT4_GOOD_OLD_INODE_SIZE,
71                                    offset - EXT4_GOOD_OLD_INODE_SIZE);
72                 if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
73                         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
74                                            csum_size);
75                         offset += csum_size;
76                 }
77                 csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
78                                    EXT4_INODE_SIZE(inode->i_sb) - offset);
79         }
80
81         return csum;
82 }
83
84 static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
85                                   struct ext4_inode_info *ei)
86 {
87         __u32 provided, calculated;
88
89         if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
90             cpu_to_le32(EXT4_OS_LINUX) ||
91             !ext4_has_metadata_csum(inode->i_sb))
92                 return 1;
93
94         provided = le16_to_cpu(raw->i_checksum_lo);
95         calculated = ext4_inode_csum(inode, raw, ei);
96         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
97             EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
98                 provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
99         else
100                 calculated &= 0xFFFF;
101
102         return provided == calculated;
103 }
104
105 void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
106                          struct ext4_inode_info *ei)
107 {
108         __u32 csum;
109
110         if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
111             cpu_to_le32(EXT4_OS_LINUX) ||
112             !ext4_has_metadata_csum(inode->i_sb))
113                 return;
114
115         csum = ext4_inode_csum(inode, raw, ei);
116         raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
117         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
118             EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
119                 raw->i_checksum_hi = cpu_to_le16(csum >> 16);
120 }
121
122 static inline int ext4_begin_ordered_truncate(struct inode *inode,
123                                               loff_t new_size)
124 {
125         trace_ext4_begin_ordered_truncate(inode, new_size);
126         /*
127          * If jinode is zero, then we never opened the file for
128          * writing, so there's no need to call
129          * jbd2_journal_begin_ordered_truncate() since there's no
130          * outstanding writes we need to flush.
131          */
132         if (!EXT4_I(inode)->jinode)
133                 return 0;
134         return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
135                                                    EXT4_I(inode)->jinode,
136                                                    new_size);
137 }
138
139 static void ext4_invalidatepage(struct page *page, unsigned int offset,
140                                 unsigned int length);
141 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
142 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
143                                   int pextents);
144
145 /*
146  * Test whether an inode is a fast symlink.
147  * A fast symlink has its symlink data stored in ext4_inode_info->i_data.
148  */
149 int ext4_inode_is_fast_symlink(struct inode *inode)
150 {
151         if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
152                 int ea_blocks = EXT4_I(inode)->i_file_acl ?
153                                 EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
154
155                 if (ext4_has_inline_data(inode))
156                         return 0;
157
158                 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
159         }
160         return S_ISLNK(inode->i_mode) && inode->i_size &&
161                (inode->i_size < EXT4_N_BLOCKS * 4);
162 }
163
164 /*
165  * Called at the last iput() if i_nlink is zero.
166  */
167 void ext4_evict_inode(struct inode *inode)
168 {
169         handle_t *handle;
170         int err;
171         /*
172          * Credits for final inode cleanup and freeing:
173          * sb + inode (ext4_orphan_del()), block bitmap, group descriptor
174          * (xattr block freeing), bitmap, group descriptor (inode freeing)
175          */
176         int extra_credits = 6;
177         struct ext4_xattr_inode_array *ea_inode_array = NULL;
178         bool freeze_protected = false;
179
180         trace_ext4_evict_inode(inode);
181
182         if (inode->i_nlink) {
183                 /*
184                  * When journalling data dirty buffers are tracked only in the
185                  * journal. So although mm thinks everything is clean and
186                  * ready for reaping the inode might still have some pages to
187                  * write in the running transaction or waiting to be
188                  * checkpointed. Thus calling jbd2_journal_invalidatepage()
189                  * (via truncate_inode_pages()) to discard these buffers can
190                  * cause data loss. Also even if we did not discard these
191                  * buffers, we would have no way to find them after the inode
192                  * is reaped and thus user could see stale data if he tries to
193                  * read them before the transaction is checkpointed. So be
194                  * careful and force everything to disk here... We use
195                  * ei->i_datasync_tid to store the newest transaction
196                  * containing inode's data.
197                  *
198                  * Note that directories do not have this problem because they
199                  * don't use page cache.
200                  */
201                 if (inode->i_ino != EXT4_JOURNAL_INO &&
202                     ext4_should_journal_data(inode) &&
203                     (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
204                     inode->i_data.nrpages) {
205                         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
206                         tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
207
208                         jbd2_complete_transaction(journal, commit_tid);
209                         filemap_write_and_wait(&inode->i_data);
210                 }
211                 truncate_inode_pages_final(&inode->i_data);
212
213                 goto no_delete;
214         }
215
216         if (is_bad_inode(inode))
217                 goto no_delete;
218         dquot_initialize(inode);
219
220         if (ext4_should_order_data(inode))
221                 ext4_begin_ordered_truncate(inode, 0);
222         truncate_inode_pages_final(&inode->i_data);
223
224         /*
225          * For inodes with journalled data, transaction commit could have
226          * dirtied the inode. Flush worker is ignoring it because of I_FREEING
227          * flag but we still need to remove the inode from the writeback lists.
228          */
229         if (!list_empty_careful(&inode->i_io_list)) {
230                 WARN_ON_ONCE(!ext4_should_journal_data(inode));
231                 inode_io_list_del(inode);
232         }
233
234         /*
235          * Protect us against freezing - iput() caller didn't have to have any
236          * protection against it. When we are in a running transaction though,
237          * we are already protected against freezing and we cannot grab further
238          * protection due to lock ordering constraints.
239          */
240         if (!ext4_journal_current_handle()) {
241                 sb_start_intwrite(inode->i_sb);
242                 freeze_protected = true;
243         }
244
245         if (!IS_NOQUOTA(inode))
246                 extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
247
248         /*
249          * Block bitmap, group descriptor, and inode are accounted in both
250          * ext4_blocks_for_truncate() and extra_credits. So subtract 3.
251          */
252         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
253                          ext4_blocks_for_truncate(inode) + extra_credits - 3);
254         if (IS_ERR(handle)) {
255                 ext4_std_error(inode->i_sb, PTR_ERR(handle));
256                 /*
257                  * If we're going to skip the normal cleanup, we still need to
258                  * make sure that the in-core orphan linked list is properly
259                  * cleaned up.
260                  */
261                 ext4_orphan_del(NULL, inode);
262                 if (freeze_protected)
263                         sb_end_intwrite(inode->i_sb);
264                 goto no_delete;
265         }
266
267         if (IS_SYNC(inode))
268                 ext4_handle_sync(handle);
269
270         /*
271          * Set inode->i_size to 0 before calling ext4_truncate(). We need
272          * special handling of symlinks here because i_size is used to
273          * determine whether ext4_inode_info->i_data contains symlink data or
274          * block mappings. Setting i_size to 0 will remove its fast symlink
275          * status. Erase i_data so that it becomes a valid empty block map.
276          */
277         if (ext4_inode_is_fast_symlink(inode))
278                 memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
279         inode->i_size = 0;
280         err = ext4_mark_inode_dirty(handle, inode);
281         if (err) {
282                 ext4_warning(inode->i_sb,
283                              "couldn't mark inode dirty (err %d)", err);
284                 goto stop_handle;
285         }
286         if (inode->i_blocks) {
287                 err = ext4_truncate(inode);
288                 if (err) {
289                         ext4_error_err(inode->i_sb, -err,
290                                        "couldn't truncate inode %lu (err %d)",
291                                        inode->i_ino, err);
292                         goto stop_handle;
293                 }
294         }
295
296         /* Remove xattr references. */
297         err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
298                                       extra_credits);
299         if (err) {
300                 ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
301 stop_handle:
302                 ext4_journal_stop(handle);
303                 ext4_orphan_del(NULL, inode);
304                 if (freeze_protected)
305                         sb_end_intwrite(inode->i_sb);
306                 ext4_xattr_inode_array_free(ea_inode_array);
307                 goto no_delete;
308         }
309
310         /*
311          * Kill off the orphan record which ext4_truncate created.
312          * AKPM: I think this can be inside the above `if'.
313          * Note that ext4_orphan_del() has to be able to cope with the
314          * deletion of a non-existent orphan - this is because we don't
315          * know if ext4_truncate() actually created an orphan record.
316          * (Well, we could do this if we need to, but heck - it works)
317          */
318         ext4_orphan_del(handle, inode);
319         EXT4_I(inode)->i_dtime  = (__u32)ktime_get_real_seconds();
320
321         /*
322          * One subtle ordering requirement: if anything has gone wrong
323          * (transaction abort, IO errors, whatever), then we can still
324          * do these next steps (the fs will already have been marked as
325          * having errors), but we can't free the inode if the mark_dirty
326          * fails.
327          */
328         if (ext4_mark_inode_dirty(handle, inode))
329                 /* If that failed, just do the required in-core inode clear. */
330                 ext4_clear_inode(inode);
331         else
332                 ext4_free_inode(handle, inode);
333         ext4_journal_stop(handle);
334         if (freeze_protected)
335                 sb_end_intwrite(inode->i_sb);
336         ext4_xattr_inode_array_free(ea_inode_array);
337         return;
338 no_delete:
339         if (!list_empty(&EXT4_I(inode)->i_fc_list))
340                 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM);
341         ext4_clear_inode(inode);        /* We must guarantee clearing of inode... */
342 }
343
344 #ifdef CONFIG_QUOTA
345 qsize_t *ext4_get_reserved_space(struct inode *inode)
346 {
347         return &EXT4_I(inode)->i_reserved_quota;
348 }
349 #endif
350
351 /*
352  * Called with i_data_sem down, which is important since we can call
353  * ext4_discard_preallocations() from here.
354  */
355 void ext4_da_update_reserve_space(struct inode *inode,
356                                         int used, int quota_claim)
357 {
358         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
359         struct ext4_inode_info *ei = EXT4_I(inode);
360
361         spin_lock(&ei->i_block_reservation_lock);
362         trace_ext4_da_update_reserve_space(inode, used, quota_claim);
363         if (unlikely(used > ei->i_reserved_data_blocks)) {
364                 ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
365                          "with only %d reserved data blocks",
366                          __func__, inode->i_ino, used,
367                          ei->i_reserved_data_blocks);
368                 WARN_ON(1);
369                 used = ei->i_reserved_data_blocks;
370         }
371
372         /* Update per-inode reservations */
373         ei->i_reserved_data_blocks -= used;
374         percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
375
376         spin_unlock(&ei->i_block_reservation_lock);
377
378         /* Update quota subsystem for data blocks */
379         if (quota_claim)
380                 dquot_claim_block(inode, EXT4_C2B(sbi, used));
381         else {
382                 /*
383                  * We did fallocate with an offset that is already delayed
384                  * allocated. So on delayed allocated writeback we should
385                  * not re-claim the quota for fallocated blocks.
386                  */
387                 dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
388         }
389
390         /*
391          * If we have done all the pending block allocations and if
392          * there aren't any writers on the inode, we can discard the
393          * inode's preallocations.
394          */
395         if ((ei->i_reserved_data_blocks == 0) &&
396             !inode_is_open_for_write(inode))
397                 ext4_discard_preallocations(inode, 0);
398 }
399
400 static int __check_block_validity(struct inode *inode, const char *func,
401                                 unsigned int line,
402                                 struct ext4_map_blocks *map)
403 {
404         if (ext4_has_feature_journal(inode->i_sb) &&
405             (inode->i_ino ==
406              le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
407                 return 0;
408         if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
409                 ext4_error_inode(inode, func, line, map->m_pblk,
410                                  "lblock %lu mapped to illegal pblock %llu "
411                                  "(length %d)", (unsigned long) map->m_lblk,
412                                  map->m_pblk, map->m_len);
413                 return -EFSCORRUPTED;
414         }
415         return 0;
416 }
417
418 int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
419                        ext4_lblk_t len)
420 {
421         int ret;
422
423         if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
424                 return fscrypt_zeroout_range(inode, lblk, pblk, len);
425
426         ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
427         if (ret > 0)
428                 ret = 0;
429
430         return ret;
431 }
432
433 #define check_block_validity(inode, map)        \
434         __check_block_validity((inode), __func__, __LINE__, (map))
435
436 #ifdef ES_AGGRESSIVE_TEST
437 static void ext4_map_blocks_es_recheck(handle_t *handle,
438                                        struct inode *inode,
439                                        struct ext4_map_blocks *es_map,
440                                        struct ext4_map_blocks *map,
441                                        int flags)
442 {
443         int retval;
444
445         map->m_flags = 0;
446         /*
447          * There is a race window that the result is not the same.
448          * e.g. xfstests #223 when dioread_nolock enables.  The reason
449          * is that we lookup a block mapping in extent status tree with
450          * out taking i_data_sem.  So at the time the unwritten extent
451          * could be converted.
452          */
453         down_read(&EXT4_I(inode)->i_data_sem);
454         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
455                 retval = ext4_ext_map_blocks(handle, inode, map, 0);
456         } else {
457                 retval = ext4_ind_map_blocks(handle, inode, map, 0);
458         }
459         up_read((&EXT4_I(inode)->i_data_sem));
460
461         /*
462          * We don't check m_len because extent will be collpased in status
463          * tree.  So the m_len might not equal.
464          */
465         if (es_map->m_lblk != map->m_lblk ||
466             es_map->m_flags != map->m_flags ||
467             es_map->m_pblk != map->m_pblk) {
468                 printk("ES cache assertion failed for inode: %lu "
469                        "es_cached ex [%d/%d/%llu/%x] != "
470                        "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
471                        inode->i_ino, es_map->m_lblk, es_map->m_len,
472                        es_map->m_pblk, es_map->m_flags, map->m_lblk,
473                        map->m_len, map->m_pblk, map->m_flags,
474                        retval, flags);
475         }
476 }
477 #endif /* ES_AGGRESSIVE_TEST */
478
479 /*
480  * The ext4_map_blocks() function tries to look up the requested blocks,
481  * and returns if the blocks are already mapped.
482  *
483  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
484  * and store the allocated blocks in the result buffer head and mark it
485  * mapped.
486  *
487  * If file type is extents based, it will call ext4_ext_map_blocks(),
488  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
489  * based files
490  *
491  * On success, it returns the number of blocks being mapped or allocated.  if
492  * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
493  * is marked as unwritten. If the create == 1, it will mark @map as mapped.
494  *
495  * It returns 0 if plain look up failed (blocks have not been allocated), in
496  * that case, @map is returned as unmapped but we still do fill map->m_len to
497  * indicate the length of a hole starting at map->m_lblk.
498  *
499  * It returns the error in case of allocation failure.
500  */
501 int ext4_map_blocks(handle_t *handle, struct inode *inode,
502                     struct ext4_map_blocks *map, int flags)
503 {
504         struct extent_status es;
505         int retval;
506         int ret = 0;
507 #ifdef ES_AGGRESSIVE_TEST
508         struct ext4_map_blocks orig_map;
509
510         memcpy(&orig_map, map, sizeof(*map));
511 #endif
512
513         map->m_flags = 0;
514         ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
515                   flags, map->m_len, (unsigned long) map->m_lblk);
516
517         /*
518          * ext4_map_blocks returns an int, and m_len is an unsigned int
519          */
520         if (unlikely(map->m_len > INT_MAX))
521                 map->m_len = INT_MAX;
522
523         /* We can handle the block number less than EXT_MAX_BLOCKS */
524         if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
525                 return -EFSCORRUPTED;
526
527         /* Lookup extent status tree firstly */
528         if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
529             ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
530                 if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
531                         map->m_pblk = ext4_es_pblock(&es) +
532                                         map->m_lblk - es.es_lblk;
533                         map->m_flags |= ext4_es_is_written(&es) ?
534                                         EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
535                         retval = es.es_len - (map->m_lblk - es.es_lblk);
536                         if (retval > map->m_len)
537                                 retval = map->m_len;
538                         map->m_len = retval;
539                 } else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
540                         map->m_pblk = 0;
541                         retval = es.es_len - (map->m_lblk - es.es_lblk);
542                         if (retval > map->m_len)
543                                 retval = map->m_len;
544                         map->m_len = retval;
545                         retval = 0;
546                 } else {
547                         BUG();
548                 }
549 #ifdef ES_AGGRESSIVE_TEST
550                 ext4_map_blocks_es_recheck(handle, inode, map,
551                                            &orig_map, flags);
552 #endif
553                 goto found;
554         }
555
556         /*
557          * Try to see if we can get the block without requesting a new
558          * file system block.
559          */
560         down_read(&EXT4_I(inode)->i_data_sem);
561         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
562                 retval = ext4_ext_map_blocks(handle, inode, map, 0);
563         } else {
564                 retval = ext4_ind_map_blocks(handle, inode, map, 0);
565         }
566         if (retval > 0) {
567                 unsigned int status;
568
569                 if (unlikely(retval != map->m_len)) {
570                         ext4_warning(inode->i_sb,
571                                      "ES len assertion failed for inode "
572                                      "%lu: retval %d != map->m_len %d",
573                                      inode->i_ino, retval, map->m_len);
574                         WARN_ON(1);
575                 }
576
577                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
578                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
579                 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
580                     !(status & EXTENT_STATUS_WRITTEN) &&
581                     ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
582                                        map->m_lblk + map->m_len - 1))
583                         status |= EXTENT_STATUS_DELAYED;
584                 ret = ext4_es_insert_extent(inode, map->m_lblk,
585                                             map->m_len, map->m_pblk, status);
586                 if (ret < 0)
587                         retval = ret;
588         }
589         up_read((&EXT4_I(inode)->i_data_sem));
590
591 found:
592         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
593                 ret = check_block_validity(inode, map);
594                 if (ret != 0)
595                         return ret;
596         }
597
598         /* If it is only a block(s) look up */
599         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
600                 return retval;
601
602         /*
603          * Returns if the blocks have already allocated
604          *
605          * Note that if blocks have been preallocated
606          * ext4_ext_get_block() returns the create = 0
607          * with buffer head unmapped.
608          */
609         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
610                 /*
611                  * If we need to convert extent to unwritten
612                  * we continue and do the actual work in
613                  * ext4_ext_map_blocks()
614                  */
615                 if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
616                         return retval;
617
618         /*
619          * Here we clear m_flags because after allocating an new extent,
620          * it will be set again.
621          */
622         map->m_flags &= ~EXT4_MAP_FLAGS;
623
624         /*
625          * New blocks allocate and/or writing to unwritten extent
626          * will possibly result in updating i_data, so we take
627          * the write lock of i_data_sem, and call get_block()
628          * with create == 1 flag.
629          */
630         down_write(&EXT4_I(inode)->i_data_sem);
631
632         /*
633          * We need to check for EXT4 here because migrate
634          * could have changed the inode type in between
635          */
636         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
637                 retval = ext4_ext_map_blocks(handle, inode, map, flags);
638         } else {
639                 retval = ext4_ind_map_blocks(handle, inode, map, flags);
640
641                 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
642                         /*
643                          * We allocated new blocks which will result in
644                          * i_data's format changing.  Force the migrate
645                          * to fail by clearing migrate flags
646                          */
647                         ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
648                 }
649
650                 /*
651                  * Update reserved blocks/metadata blocks after successful
652                  * block allocation which had been deferred till now. We don't
653                  * support fallocate for non extent files. So we can update
654                  * reserve space here.
655                  */
656                 if ((retval > 0) &&
657                         (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
658                         ext4_da_update_reserve_space(inode, retval, 1);
659         }
660
661         if (retval > 0) {
662                 unsigned int status;
663
664                 if (unlikely(retval != map->m_len)) {
665                         ext4_warning(inode->i_sb,
666                                      "ES len assertion failed for inode "
667                                      "%lu: retval %d != map->m_len %d",
668                                      inode->i_ino, retval, map->m_len);
669                         WARN_ON(1);
670                 }
671
672                 /*
673                  * We have to zeroout blocks before inserting them into extent
674                  * status tree. Otherwise someone could look them up there and
675                  * use them before they are really zeroed. We also have to
676                  * unmap metadata before zeroing as otherwise writeback can
677                  * overwrite zeros with stale data from block device.
678                  */
679                 if (flags & EXT4_GET_BLOCKS_ZERO &&
680                     map->m_flags & EXT4_MAP_MAPPED &&
681                     map->m_flags & EXT4_MAP_NEW) {
682                         ret = ext4_issue_zeroout(inode, map->m_lblk,
683                                                  map->m_pblk, map->m_len);
684                         if (ret) {
685                                 retval = ret;
686                                 goto out_sem;
687                         }
688                 }
689
690                 /*
691                  * If the extent has been zeroed out, we don't need to update
692                  * extent status tree.
693                  */
694                 if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
695                     ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
696                         if (ext4_es_is_written(&es))
697                                 goto out_sem;
698                 }
699                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
700                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
701                 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
702                     !(status & EXTENT_STATUS_WRITTEN) &&
703                     ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
704                                        map->m_lblk + map->m_len - 1))
705                         status |= EXTENT_STATUS_DELAYED;
706                 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
707                                             map->m_pblk, status);
708                 if (ret < 0) {
709                         retval = ret;
710                         goto out_sem;
711                 }
712         }
713
714 out_sem:
715         up_write((&EXT4_I(inode)->i_data_sem));
716         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
717                 ret = check_block_validity(inode, map);
718                 if (ret != 0)
719                         return ret;
720
721                 /*
722                  * Inodes with freshly allocated blocks where contents will be
723                  * visible after transaction commit must be on transaction's
724                  * ordered data list.
725                  */
726                 if (map->m_flags & EXT4_MAP_NEW &&
727                     !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
728                     !(flags & EXT4_GET_BLOCKS_ZERO) &&
729                     !ext4_is_quota_file(inode) &&
730                     ext4_should_order_data(inode)) {
731                         loff_t start_byte =
732                                 (loff_t)map->m_lblk << inode->i_blkbits;
733                         loff_t length = (loff_t)map->m_len << inode->i_blkbits;
734
735                         if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
736                                 ret = ext4_jbd2_inode_add_wait(handle, inode,
737                                                 start_byte, length);
738                         else
739                                 ret = ext4_jbd2_inode_add_write(handle, inode,
740                                                 start_byte, length);
741                         if (ret)
742                                 return ret;
743                 }
744                 ext4_fc_track_range(handle, inode, map->m_lblk,
745                             map->m_lblk + map->m_len - 1);
746         }
747
748         if (retval < 0)
749                 ext_debug(inode, "failed with err %d\n", retval);
750         return retval;
751 }
752
753 /*
754  * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
755  * we have to be careful as someone else may be manipulating b_state as well.
756  */
757 static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
758 {
759         unsigned long old_state;
760         unsigned long new_state;
761
762         flags &= EXT4_MAP_FLAGS;
763
764         /* Dummy buffer_head? Set non-atomically. */
765         if (!bh->b_page) {
766                 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
767                 return;
768         }
769         /*
770          * Someone else may be modifying b_state. Be careful! This is ugly but
771          * once we get rid of using bh as a container for mapping information
772          * to pass to / from get_block functions, this can go away.
773          */
774         do {
775                 old_state = READ_ONCE(bh->b_state);
776                 new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
777         } while (unlikely(
778                  cmpxchg(&bh->b_state, old_state, new_state) != old_state));
779 }
780
781 static int _ext4_get_block(struct inode *inode, sector_t iblock,
782                            struct buffer_head *bh, int flags)
783 {
784         struct ext4_map_blocks map;
785         int ret = 0;
786
787         if (ext4_has_inline_data(inode))
788                 return -ERANGE;
789
790         map.m_lblk = iblock;
791         map.m_len = bh->b_size >> inode->i_blkbits;
792
793         ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
794                               flags);
795         if (ret > 0) {
796                 map_bh(bh, inode->i_sb, map.m_pblk);
797                 ext4_update_bh_state(bh, map.m_flags);
798                 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
799                 ret = 0;
800         } else if (ret == 0) {
801                 /* hole case, need to fill in bh->b_size */
802                 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
803         }
804         return ret;
805 }
806
807 int ext4_get_block(struct inode *inode, sector_t iblock,
808                    struct buffer_head *bh, int create)
809 {
810         return _ext4_get_block(inode, iblock, bh,
811                                create ? EXT4_GET_BLOCKS_CREATE : 0);
812 }
813
814 /*
815  * Get block function used when preparing for buffered write if we require
816  * creating an unwritten extent if blocks haven't been allocated.  The extent
817  * will be converted to written after the IO is complete.
818  */
819 int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
820                              struct buffer_head *bh_result, int create)
821 {
822         ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
823                    inode->i_ino, create);
824         return _ext4_get_block(inode, iblock, bh_result,
825                                EXT4_GET_BLOCKS_IO_CREATE_EXT);
826 }
827
828 /* Maximum number of blocks we map for direct IO at once. */
829 #define DIO_MAX_BLOCKS 4096
830
831 /*
832  * `handle' can be NULL if create is zero
833  */
834 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
835                                 ext4_lblk_t block, int map_flags)
836 {
837         struct ext4_map_blocks map;
838         struct buffer_head *bh;
839         int create = map_flags & EXT4_GET_BLOCKS_CREATE;
840         int err;
841
842         ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
843                     || handle != NULL || create == 0);
844
845         map.m_lblk = block;
846         map.m_len = 1;
847         err = ext4_map_blocks(handle, inode, &map, map_flags);
848
849         if (err == 0)
850                 return create ? ERR_PTR(-ENOSPC) : NULL;
851         if (err < 0)
852                 return ERR_PTR(err);
853
854         bh = sb_getblk(inode->i_sb, map.m_pblk);
855         if (unlikely(!bh))
856                 return ERR_PTR(-ENOMEM);
857         if (map.m_flags & EXT4_MAP_NEW) {
858                 ASSERT(create != 0);
859                 ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
860                             || (handle != NULL));
861
862                 /*
863                  * Now that we do not always journal data, we should
864                  * keep in mind whether this should always journal the
865                  * new buffer as metadata.  For now, regular file
866                  * writes use ext4_get_block instead, so it's not a
867                  * problem.
868                  */
869                 lock_buffer(bh);
870                 BUFFER_TRACE(bh, "call get_create_access");
871                 err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
872                                                      EXT4_JTR_NONE);
873                 if (unlikely(err)) {
874                         unlock_buffer(bh);
875                         goto errout;
876                 }
877                 if (!buffer_uptodate(bh)) {
878                         memset(bh->b_data, 0, inode->i_sb->s_blocksize);
879                         set_buffer_uptodate(bh);
880                 }
881                 unlock_buffer(bh);
882                 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
883                 err = ext4_handle_dirty_metadata(handle, inode, bh);
884                 if (unlikely(err))
885                         goto errout;
886         } else
887                 BUFFER_TRACE(bh, "not a new buffer");
888         return bh;
889 errout:
890         brelse(bh);
891         return ERR_PTR(err);
892 }
893
894 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
895                                ext4_lblk_t block, int map_flags)
896 {
897         struct buffer_head *bh;
898         int ret;
899
900         bh = ext4_getblk(handle, inode, block, map_flags);
901         if (IS_ERR(bh))
902                 return bh;
903         if (!bh || ext4_buffer_uptodate(bh))
904                 return bh;
905
906         ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
907         if (ret) {
908                 put_bh(bh);
909                 return ERR_PTR(ret);
910         }
911         return bh;
912 }
913
914 /* Read a contiguous batch of blocks. */
915 int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
916                      bool wait, struct buffer_head **bhs)
917 {
918         int i, err;
919
920         for (i = 0; i < bh_count; i++) {
921                 bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
922                 if (IS_ERR(bhs[i])) {
923                         err = PTR_ERR(bhs[i]);
924                         bh_count = i;
925                         goto out_brelse;
926                 }
927         }
928
929         for (i = 0; i < bh_count; i++)
930                 /* Note that NULL bhs[i] is valid because of holes. */
931                 if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
932                         ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
933
934         if (!wait)
935                 return 0;
936
937         for (i = 0; i < bh_count; i++)
938                 if (bhs[i])
939                         wait_on_buffer(bhs[i]);
940
941         for (i = 0; i < bh_count; i++) {
942                 if (bhs[i] && !buffer_uptodate(bhs[i])) {
943                         err = -EIO;
944                         goto out_brelse;
945                 }
946         }
947         return 0;
948
949 out_brelse:
950         for (i = 0; i < bh_count; i++) {
951                 brelse(bhs[i]);
952                 bhs[i] = NULL;
953         }
954         return err;
955 }
956
957 int ext4_walk_page_buffers(handle_t *handle, struct inode *inode,
958                            struct buffer_head *head,
959                            unsigned from,
960                            unsigned to,
961                            int *partial,
962                            int (*fn)(handle_t *handle, struct inode *inode,
963                                      struct buffer_head *bh))
964 {
965         struct buffer_head *bh;
966         unsigned block_start, block_end;
967         unsigned blocksize = head->b_size;
968         int err, ret = 0;
969         struct buffer_head *next;
970
971         for (bh = head, block_start = 0;
972              ret == 0 && (bh != head || !block_start);
973              block_start = block_end, bh = next) {
974                 next = bh->b_this_page;
975                 block_end = block_start + blocksize;
976                 if (block_end <= from || block_start >= to) {
977                         if (partial && !buffer_uptodate(bh))
978                                 *partial = 1;
979                         continue;
980                 }
981                 err = (*fn)(handle, inode, bh);
982                 if (!ret)
983                         ret = err;
984         }
985         return ret;
986 }
987
988 /*
989  * To preserve ordering, it is essential that the hole instantiation and
990  * the data write be encapsulated in a single transaction.  We cannot
991  * close off a transaction and start a new one between the ext4_get_block()
992  * and the commit_write().  So doing the jbd2_journal_start at the start of
993  * prepare_write() is the right place.
994  *
995  * Also, this function can nest inside ext4_writepage().  In that case, we
996  * *know* that ext4_writepage() has generated enough buffer credits to do the
997  * whole page.  So we won't block on the journal in that case, which is good,
998  * because the caller may be PF_MEMALLOC.
999  *
1000  * By accident, ext4 can be reentered when a transaction is open via
1001  * quota file writes.  If we were to commit the transaction while thus
1002  * reentered, there can be a deadlock - we would be holding a quota
1003  * lock, and the commit would never complete if another thread had a
1004  * transaction open and was blocking on the quota lock - a ranking
1005  * violation.
1006  *
1007  * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1008  * will _not_ run commit under these circumstances because handle->h_ref
1009  * is elevated.  We'll still have enough credits for the tiny quotafile
1010  * write.
1011  */
1012 int do_journal_get_write_access(handle_t *handle, struct inode *inode,
1013                                 struct buffer_head *bh)
1014 {
1015         int dirty = buffer_dirty(bh);
1016         int ret;
1017
1018         if (!buffer_mapped(bh) || buffer_freed(bh))
1019                 return 0;
1020         /*
1021          * __block_write_begin() could have dirtied some buffers. Clean
1022          * the dirty bit as jbd2_journal_get_write_access() could complain
1023          * otherwise about fs integrity issues. Setting of the dirty bit
1024          * by __block_write_begin() isn't a real problem here as we clear
1025          * the bit before releasing a page lock and thus writeback cannot
1026          * ever write the buffer.
1027          */
1028         if (dirty)
1029                 clear_buffer_dirty(bh);
1030         BUFFER_TRACE(bh, "get write access");
1031         ret = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1032                                             EXT4_JTR_NONE);
1033         if (!ret && dirty)
1034                 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1035         return ret;
1036 }
1037
1038 #ifdef CONFIG_FS_ENCRYPTION
1039 static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
1040                                   get_block_t *get_block)
1041 {
1042         unsigned from = pos & (PAGE_SIZE - 1);
1043         unsigned to = from + len;
1044         struct inode *inode = page->mapping->host;
1045         unsigned block_start, block_end;
1046         sector_t block;
1047         int err = 0;
1048         unsigned blocksize = inode->i_sb->s_blocksize;
1049         unsigned bbits;
1050         struct buffer_head *bh, *head, *wait[2];
1051         int nr_wait = 0;
1052         int i;
1053
1054         BUG_ON(!PageLocked(page));
1055         BUG_ON(from > PAGE_SIZE);
1056         BUG_ON(to > PAGE_SIZE);
1057         BUG_ON(from > to);
1058
1059         if (!page_has_buffers(page))
1060                 create_empty_buffers(page, blocksize, 0);
1061         head = page_buffers(page);
1062         bbits = ilog2(blocksize);
1063         block = (sector_t)page->index << (PAGE_SHIFT - bbits);
1064
1065         for (bh = head, block_start = 0; bh != head || !block_start;
1066             block++, block_start = block_end, bh = bh->b_this_page) {
1067                 block_end = block_start + blocksize;
1068                 if (block_end <= from || block_start >= to) {
1069                         if (PageUptodate(page)) {
1070                                 set_buffer_uptodate(bh);
1071                         }
1072                         continue;
1073                 }
1074                 if (buffer_new(bh))
1075                         clear_buffer_new(bh);
1076                 if (!buffer_mapped(bh)) {
1077                         WARN_ON(bh->b_size != blocksize);
1078                         err = get_block(inode, block, bh, 1);
1079                         if (err)
1080                                 break;
1081                         if (buffer_new(bh)) {
1082                                 if (PageUptodate(page)) {
1083                                         clear_buffer_new(bh);
1084                                         set_buffer_uptodate(bh);
1085                                         mark_buffer_dirty(bh);
1086                                         continue;
1087                                 }
1088                                 if (block_end > to || block_start < from)
1089                                         zero_user_segments(page, to, block_end,
1090                                                            block_start, from);
1091                                 continue;
1092                         }
1093                 }
1094                 if (PageUptodate(page)) {
1095                         set_buffer_uptodate(bh);
1096                         continue;
1097                 }
1098                 if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1099                     !buffer_unwritten(bh) &&
1100                     (block_start < from || block_end > to)) {
1101                         ext4_read_bh_lock(bh, 0, false);
1102                         wait[nr_wait++] = bh;
1103                 }
1104         }
1105         /*
1106          * If we issued read requests, let them complete.
1107          */
1108         for (i = 0; i < nr_wait; i++) {
1109                 wait_on_buffer(wait[i]);
1110                 if (!buffer_uptodate(wait[i]))
1111                         err = -EIO;
1112         }
1113         if (unlikely(err)) {
1114                 page_zero_new_buffers(page, from, to);
1115         } else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
1116                 for (i = 0; i < nr_wait; i++) {
1117                         int err2;
1118
1119                         err2 = fscrypt_decrypt_pagecache_blocks(page, blocksize,
1120                                                                 bh_offset(wait[i]));
1121                         if (err2) {
1122                                 clear_buffer_uptodate(wait[i]);
1123                                 err = err2;
1124                         }
1125                 }
1126         }
1127
1128         return err;
1129 }
1130 #endif
1131
1132 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1133                             loff_t pos, unsigned len, unsigned flags,
1134                             struct page **pagep, void **fsdata)
1135 {
1136         struct inode *inode = mapping->host;
1137         int ret, needed_blocks;
1138         handle_t *handle;
1139         int retries = 0;
1140         struct page *page;
1141         pgoff_t index;
1142         unsigned from, to;
1143
1144         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
1145                 return -EIO;
1146
1147         trace_ext4_write_begin(inode, pos, len, flags);
1148         /*
1149          * Reserve one block more for addition to orphan list in case
1150          * we allocate blocks but write fails for some reason
1151          */
1152         needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1153         index = pos >> PAGE_SHIFT;
1154         from = pos & (PAGE_SIZE - 1);
1155         to = from + len;
1156
1157         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1158                 ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1159                                                     flags, pagep);
1160                 if (ret < 0)
1161                         return ret;
1162                 if (ret == 1)
1163                         return 0;
1164         }
1165
1166         /*
1167          * grab_cache_page_write_begin() can take a long time if the
1168          * system is thrashing due to memory pressure, or if the page
1169          * is being written back.  So grab it first before we start
1170          * the transaction handle.  This also allows us to allocate
1171          * the page (if needed) without using GFP_NOFS.
1172          */
1173 retry_grab:
1174         page = grab_cache_page_write_begin(mapping, index, flags);
1175         if (!page)
1176                 return -ENOMEM;
1177         unlock_page(page);
1178
1179 retry_journal:
1180         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1181         if (IS_ERR(handle)) {
1182                 put_page(page);
1183                 return PTR_ERR(handle);
1184         }
1185
1186         lock_page(page);
1187         if (page->mapping != mapping) {
1188                 /* The page got truncated from under us */
1189                 unlock_page(page);
1190                 put_page(page);
1191                 ext4_journal_stop(handle);
1192                 goto retry_grab;
1193         }
1194         /* In case writeback began while the page was unlocked */
1195         wait_for_stable_page(page);
1196
1197 #ifdef CONFIG_FS_ENCRYPTION
1198         if (ext4_should_dioread_nolock(inode))
1199                 ret = ext4_block_write_begin(page, pos, len,
1200                                              ext4_get_block_unwritten);
1201         else
1202                 ret = ext4_block_write_begin(page, pos, len,
1203                                              ext4_get_block);
1204 #else
1205         if (ext4_should_dioread_nolock(inode))
1206                 ret = __block_write_begin(page, pos, len,
1207                                           ext4_get_block_unwritten);
1208         else
1209                 ret = __block_write_begin(page, pos, len, ext4_get_block);
1210 #endif
1211         if (!ret && ext4_should_journal_data(inode)) {
1212                 ret = ext4_walk_page_buffers(handle, inode,
1213                                              page_buffers(page), from, to, NULL,
1214                                              do_journal_get_write_access);
1215         }
1216
1217         if (ret) {
1218                 bool extended = (pos + len > inode->i_size) &&
1219                                 !ext4_verity_in_progress(inode);
1220
1221                 unlock_page(page);
1222                 /*
1223                  * __block_write_begin may have instantiated a few blocks
1224                  * outside i_size.  Trim these off again. Don't need
1225                  * i_size_read because we hold i_mutex.
1226                  *
1227                  * Add inode to orphan list in case we crash before
1228                  * truncate finishes
1229                  */
1230                 if (extended && ext4_can_truncate(inode))
1231                         ext4_orphan_add(handle, inode);
1232
1233                 ext4_journal_stop(handle);
1234                 if (extended) {
1235                         ext4_truncate_failed_write(inode);
1236                         /*
1237                          * If truncate failed early the inode might
1238                          * still be on the orphan list; we need to
1239                          * make sure the inode is removed from the
1240                          * orphan list in that case.
1241                          */
1242                         if (inode->i_nlink)
1243                                 ext4_orphan_del(NULL, inode);
1244                 }
1245
1246                 if (ret == -ENOSPC &&
1247                     ext4_should_retry_alloc(inode->i_sb, &retries))
1248                         goto retry_journal;
1249                 put_page(page);
1250                 return ret;
1251         }
1252         *pagep = page;
1253         return ret;
1254 }
1255
1256 /* For write_end() in data=journal mode */
1257 static int write_end_fn(handle_t *handle, struct inode *inode,
1258                         struct buffer_head *bh)
1259 {
1260         int ret;
1261         if (!buffer_mapped(bh) || buffer_freed(bh))
1262                 return 0;
1263         set_buffer_uptodate(bh);
1264         ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1265         clear_buffer_meta(bh);
1266         clear_buffer_prio(bh);
1267         return ret;
1268 }
1269
1270 /*
1271  * We need to pick up the new inode size which generic_commit_write gave us
1272  * `file' can be NULL - eg, when called from page_symlink().
1273  *
1274  * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1275  * buffers are managed internally.
1276  */
1277 static int ext4_write_end(struct file *file,
1278                           struct address_space *mapping,
1279                           loff_t pos, unsigned len, unsigned copied,
1280                           struct page *page, void *fsdata)
1281 {
1282         handle_t *handle = ext4_journal_current_handle();
1283         struct inode *inode = mapping->host;
1284         loff_t old_size = inode->i_size;
1285         int ret = 0, ret2;
1286         int i_size_changed = 0;
1287         int inline_data = ext4_has_inline_data(inode);
1288         bool verity = ext4_verity_in_progress(inode);
1289
1290         trace_ext4_write_end(inode, pos, len, copied);
1291         if (inline_data) {
1292                 ret = ext4_write_inline_data_end(inode, pos, len,
1293                                                  copied, page);
1294                 if (ret < 0) {
1295                         unlock_page(page);
1296                         put_page(page);
1297                         goto errout;
1298                 }
1299                 copied = ret;
1300         } else
1301                 copied = block_write_end(file, mapping, pos,
1302                                          len, copied, page, fsdata);
1303         /*
1304          * it's important to update i_size while still holding page lock:
1305          * page writeout could otherwise come in and zero beyond i_size.
1306          *
1307          * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1308          * blocks are being written past EOF, so skip the i_size update.
1309          */
1310         if (!verity)
1311                 i_size_changed = ext4_update_inode_size(inode, pos + copied);
1312         unlock_page(page);
1313         put_page(page);
1314
1315         if (old_size < pos && !verity)
1316                 pagecache_isize_extended(inode, old_size, pos);
1317         /*
1318          * Don't mark the inode dirty under page lock. First, it unnecessarily
1319          * makes the holding time of page lock longer. Second, it forces lock
1320          * ordering of page lock and transaction start for journaling
1321          * filesystems.
1322          */
1323         if (i_size_changed || inline_data)
1324                 ret = ext4_mark_inode_dirty(handle, inode);
1325
1326         if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1327                 /* if we have allocated more blocks and copied
1328                  * less. We will have blocks allocated outside
1329                  * inode->i_size. So truncate them
1330                  */
1331                 ext4_orphan_add(handle, inode);
1332 errout:
1333         ret2 = ext4_journal_stop(handle);
1334         if (!ret)
1335                 ret = ret2;
1336
1337         if (pos + len > inode->i_size && !verity) {
1338                 ext4_truncate_failed_write(inode);
1339                 /*
1340                  * If truncate failed early the inode might still be
1341                  * on the orphan list; we need to make sure the inode
1342                  * is removed from the orphan list in that case.
1343                  */
1344                 if (inode->i_nlink)
1345                         ext4_orphan_del(NULL, inode);
1346         }
1347
1348         return ret ? ret : copied;
1349 }
1350
1351 /*
1352  * This is a private version of page_zero_new_buffers() which doesn't
1353  * set the buffer to be dirty, since in data=journalled mode we need
1354  * to call ext4_handle_dirty_metadata() instead.
1355  */
1356 static void ext4_journalled_zero_new_buffers(handle_t *handle,
1357                                             struct inode *inode,
1358                                             struct page *page,
1359                                             unsigned from, unsigned to)
1360 {
1361         unsigned int block_start = 0, block_end;
1362         struct buffer_head *head, *bh;
1363
1364         bh = head = page_buffers(page);
1365         do {
1366                 block_end = block_start + bh->b_size;
1367                 if (buffer_new(bh)) {
1368                         if (block_end > from && block_start < to) {
1369                                 if (!PageUptodate(page)) {
1370                                         unsigned start, size;
1371
1372                                         start = max(from, block_start);
1373                                         size = min(to, block_end) - start;
1374
1375                                         zero_user(page, start, size);
1376                                         write_end_fn(handle, inode, bh);
1377                                 }
1378                                 clear_buffer_new(bh);
1379                         }
1380                 }
1381                 block_start = block_end;
1382                 bh = bh->b_this_page;
1383         } while (bh != head);
1384 }
1385
1386 static int ext4_journalled_write_end(struct file *file,
1387                                      struct address_space *mapping,
1388                                      loff_t pos, unsigned len, unsigned copied,
1389                                      struct page *page, void *fsdata)
1390 {
1391         handle_t *handle = ext4_journal_current_handle();
1392         struct inode *inode = mapping->host;
1393         loff_t old_size = inode->i_size;
1394         int ret = 0, ret2;
1395         int partial = 0;
1396         unsigned from, to;
1397         int size_changed = 0;
1398         int inline_data = ext4_has_inline_data(inode);
1399         bool verity = ext4_verity_in_progress(inode);
1400
1401         trace_ext4_journalled_write_end(inode, pos, len, copied);
1402         from = pos & (PAGE_SIZE - 1);
1403         to = from + len;
1404
1405         BUG_ON(!ext4_handle_valid(handle));
1406
1407         if (inline_data) {
1408                 ret = ext4_write_inline_data_end(inode, pos, len,
1409                                                  copied, page);
1410                 if (ret < 0) {
1411                         unlock_page(page);
1412                         put_page(page);
1413                         goto errout;
1414                 }
1415                 copied = ret;
1416         } else if (unlikely(copied < len) && !PageUptodate(page)) {
1417                 copied = 0;
1418                 ext4_journalled_zero_new_buffers(handle, inode, page, from, to);
1419         } else {
1420                 if (unlikely(copied < len))
1421                         ext4_journalled_zero_new_buffers(handle, inode, page,
1422                                                          from + copied, to);
1423                 ret = ext4_walk_page_buffers(handle, inode, page_buffers(page),
1424                                              from, from + copied, &partial,
1425                                              write_end_fn);
1426                 if (!partial)
1427                         SetPageUptodate(page);
1428         }
1429         if (!verity)
1430                 size_changed = ext4_update_inode_size(inode, pos + copied);
1431         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1432         EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1433         unlock_page(page);
1434         put_page(page);
1435
1436         if (old_size < pos && !verity)
1437                 pagecache_isize_extended(inode, old_size, pos);
1438
1439         if (size_changed || inline_data) {
1440                 ret2 = ext4_mark_inode_dirty(handle, inode);
1441                 if (!ret)
1442                         ret = ret2;
1443         }
1444
1445         if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1446                 /* if we have allocated more blocks and copied
1447                  * less. We will have blocks allocated outside
1448                  * inode->i_size. So truncate them
1449                  */
1450                 ext4_orphan_add(handle, inode);
1451
1452 errout:
1453         ret2 = ext4_journal_stop(handle);
1454         if (!ret)
1455                 ret = ret2;
1456         if (pos + len > inode->i_size && !verity) {
1457                 ext4_truncate_failed_write(inode);
1458                 /*
1459                  * If truncate failed early the inode might still be
1460                  * on the orphan list; we need to make sure the inode
1461                  * is removed from the orphan list in that case.
1462                  */
1463                 if (inode->i_nlink)
1464                         ext4_orphan_del(NULL, inode);
1465         }
1466
1467         return ret ? ret : copied;
1468 }
1469
1470 /*
1471  * Reserve space for a single cluster
1472  */
1473 static int ext4_da_reserve_space(struct inode *inode)
1474 {
1475         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1476         struct ext4_inode_info *ei = EXT4_I(inode);
1477         int ret;
1478
1479         /*
1480          * We will charge metadata quota at writeout time; this saves
1481          * us from metadata over-estimation, though we may go over by
1482          * a small amount in the end.  Here we just reserve for data.
1483          */
1484         ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1485         if (ret)
1486                 return ret;
1487
1488         spin_lock(&ei->i_block_reservation_lock);
1489         if (ext4_claim_free_clusters(sbi, 1, 0)) {
1490                 spin_unlock(&ei->i_block_reservation_lock);
1491                 dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1492                 return -ENOSPC;
1493         }
1494         ei->i_reserved_data_blocks++;
1495         trace_ext4_da_reserve_space(inode);
1496         spin_unlock(&ei->i_block_reservation_lock);
1497
1498         return 0;       /* success */
1499 }
1500
1501 void ext4_da_release_space(struct inode *inode, int to_free)
1502 {
1503         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1504         struct ext4_inode_info *ei = EXT4_I(inode);
1505
1506         if (!to_free)
1507                 return;         /* Nothing to release, exit */
1508
1509         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1510
1511         trace_ext4_da_release_space(inode, to_free);
1512         if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1513                 /*
1514                  * if there aren't enough reserved blocks, then the
1515                  * counter is messed up somewhere.  Since this
1516                  * function is called from invalidate page, it's
1517                  * harmless to return without any action.
1518                  */
1519                 ext4_warning(inode->i_sb, "ext4_da_release_space: "
1520                          "ino %lu, to_free %d with only %d reserved "
1521                          "data blocks", inode->i_ino, to_free,
1522                          ei->i_reserved_data_blocks);
1523                 WARN_ON(1);
1524                 to_free = ei->i_reserved_data_blocks;
1525         }
1526         ei->i_reserved_data_blocks -= to_free;
1527
1528         /* update fs dirty data blocks counter */
1529         percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1530
1531         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1532
1533         dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1534 }
1535
1536 /*
1537  * Delayed allocation stuff
1538  */
1539
1540 struct mpage_da_data {
1541         struct inode *inode;
1542         struct writeback_control *wbc;
1543
1544         pgoff_t first_page;     /* The first page to write */
1545         pgoff_t next_page;      /* Current page to examine */
1546         pgoff_t last_page;      /* Last page to examine */
1547         /*
1548          * Extent to map - this can be after first_page because that can be
1549          * fully mapped. We somewhat abuse m_flags to store whether the extent
1550          * is delalloc or unwritten.
1551          */
1552         struct ext4_map_blocks map;
1553         struct ext4_io_submit io_submit;        /* IO submission data */
1554         unsigned int do_map:1;
1555         unsigned int scanned_until_end:1;
1556 };
1557
1558 static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1559                                        bool invalidate)
1560 {
1561         int nr_pages, i;
1562         pgoff_t index, end;
1563         struct pagevec pvec;
1564         struct inode *inode = mpd->inode;
1565         struct address_space *mapping = inode->i_mapping;
1566
1567         /* This is necessary when next_page == 0. */
1568         if (mpd->first_page >= mpd->next_page)
1569                 return;
1570
1571         mpd->scanned_until_end = 0;
1572         index = mpd->first_page;
1573         end   = mpd->next_page - 1;
1574         if (invalidate) {
1575                 ext4_lblk_t start, last;
1576                 start = index << (PAGE_SHIFT - inode->i_blkbits);
1577                 last = end << (PAGE_SHIFT - inode->i_blkbits);
1578                 ext4_es_remove_extent(inode, start, last - start + 1);
1579         }
1580
1581         pagevec_init(&pvec);
1582         while (index <= end) {
1583                 nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end);
1584                 if (nr_pages == 0)
1585                         break;
1586                 for (i = 0; i < nr_pages; i++) {
1587                         struct page *page = pvec.pages[i];
1588
1589                         BUG_ON(!PageLocked(page));
1590                         BUG_ON(PageWriteback(page));
1591                         if (invalidate) {
1592                                 if (page_mapped(page))
1593                                         clear_page_dirty_for_io(page);
1594                                 block_invalidatepage(page, 0, PAGE_SIZE);
1595                                 ClearPageUptodate(page);
1596                         }
1597                         unlock_page(page);
1598                 }
1599                 pagevec_release(&pvec);
1600         }
1601 }
1602
1603 static void ext4_print_free_blocks(struct inode *inode)
1604 {
1605         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1606         struct super_block *sb = inode->i_sb;
1607         struct ext4_inode_info *ei = EXT4_I(inode);
1608
1609         ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1610                EXT4_C2B(EXT4_SB(inode->i_sb),
1611                         ext4_count_free_clusters(sb)));
1612         ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1613         ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1614                (long long) EXT4_C2B(EXT4_SB(sb),
1615                 percpu_counter_sum(&sbi->s_freeclusters_counter)));
1616         ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1617                (long long) EXT4_C2B(EXT4_SB(sb),
1618                 percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1619         ext4_msg(sb, KERN_CRIT, "Block reservation details");
1620         ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1621                  ei->i_reserved_data_blocks);
1622         return;
1623 }
1624
1625 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct inode *inode,
1626                                       struct buffer_head *bh)
1627 {
1628         return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1629 }
1630
1631 /*
1632  * ext4_insert_delayed_block - adds a delayed block to the extents status
1633  *                             tree, incrementing the reserved cluster/block
1634  *                             count or making a pending reservation
1635  *                             where needed
1636  *
1637  * @inode - file containing the newly added block
1638  * @lblk - logical block to be added
1639  *
1640  * Returns 0 on success, negative error code on failure.
1641  */
1642 static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
1643 {
1644         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1645         int ret;
1646         bool allocated = false;
1647
1648         /*
1649          * If the cluster containing lblk is shared with a delayed,
1650          * written, or unwritten extent in a bigalloc file system, it's
1651          * already been accounted for and does not need to be reserved.
1652          * A pending reservation must be made for the cluster if it's
1653          * shared with a written or unwritten extent and doesn't already
1654          * have one.  Written and unwritten extents can be purged from the
1655          * extents status tree if the system is under memory pressure, so
1656          * it's necessary to examine the extent tree if a search of the
1657          * extents status tree doesn't get a match.
1658          */
1659         if (sbi->s_cluster_ratio == 1) {
1660                 ret = ext4_da_reserve_space(inode);
1661                 if (ret != 0)   /* ENOSPC */
1662                         goto errout;
1663         } else {   /* bigalloc */
1664                 if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
1665                         if (!ext4_es_scan_clu(inode,
1666                                               &ext4_es_is_mapped, lblk)) {
1667                                 ret = ext4_clu_mapped(inode,
1668                                                       EXT4_B2C(sbi, lblk));
1669                                 if (ret < 0)
1670                                         goto errout;
1671                                 if (ret == 0) {
1672                                         ret = ext4_da_reserve_space(inode);
1673                                         if (ret != 0)   /* ENOSPC */
1674                                                 goto errout;
1675                                 } else {
1676                                         allocated = true;
1677                                 }
1678                         } else {
1679                                 allocated = true;
1680                         }
1681                 }
1682         }
1683
1684         ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
1685
1686 errout:
1687         return ret;
1688 }
1689
1690 /*
1691  * This function is grabs code from the very beginning of
1692  * ext4_map_blocks, but assumes that the caller is from delayed write
1693  * time. This function looks up the requested blocks and sets the
1694  * buffer delay bit under the protection of i_data_sem.
1695  */
1696 static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1697                               struct ext4_map_blocks *map,
1698                               struct buffer_head *bh)
1699 {
1700         struct extent_status es;
1701         int retval;
1702         sector_t invalid_block = ~((sector_t) 0xffff);
1703 #ifdef ES_AGGRESSIVE_TEST
1704         struct ext4_map_blocks orig_map;
1705
1706         memcpy(&orig_map, map, sizeof(*map));
1707 #endif
1708
1709         if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1710                 invalid_block = ~0;
1711
1712         map->m_flags = 0;
1713         ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1714                   (unsigned long) map->m_lblk);
1715
1716         /* Lookup extent status tree firstly */
1717         if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
1718                 if (ext4_es_is_hole(&es)) {
1719                         retval = 0;
1720                         down_read(&EXT4_I(inode)->i_data_sem);
1721                         goto add_delayed;
1722                 }
1723
1724                 /*
1725                  * Delayed extent could be allocated by fallocate.
1726                  * So we need to check it.
1727                  */
1728                 if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1729                         map_bh(bh, inode->i_sb, invalid_block);
1730                         set_buffer_new(bh);
1731                         set_buffer_delay(bh);
1732                         return 0;
1733                 }
1734
1735                 map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1736                 retval = es.es_len - (iblock - es.es_lblk);
1737                 if (retval > map->m_len)
1738                         retval = map->m_len;
1739                 map->m_len = retval;
1740                 if (ext4_es_is_written(&es))
1741                         map->m_flags |= EXT4_MAP_MAPPED;
1742                 else if (ext4_es_is_unwritten(&es))
1743                         map->m_flags |= EXT4_MAP_UNWRITTEN;
1744                 else
1745                         BUG();
1746
1747 #ifdef ES_AGGRESSIVE_TEST
1748                 ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1749 #endif
1750                 return retval;
1751         }
1752
1753         /*
1754          * Try to see if we can get the block without requesting a new
1755          * file system block.
1756          */
1757         down_read(&EXT4_I(inode)->i_data_sem);
1758         if (ext4_has_inline_data(inode))
1759                 retval = 0;
1760         else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1761                 retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1762         else
1763                 retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1764
1765 add_delayed:
1766         if (retval == 0) {
1767                 int ret;
1768
1769                 /*
1770                  * XXX: __block_prepare_write() unmaps passed block,
1771                  * is it OK?
1772                  */
1773
1774                 ret = ext4_insert_delayed_block(inode, map->m_lblk);
1775                 if (ret != 0) {
1776                         retval = ret;
1777                         goto out_unlock;
1778                 }
1779
1780                 map_bh(bh, inode->i_sb, invalid_block);
1781                 set_buffer_new(bh);
1782                 set_buffer_delay(bh);
1783         } else if (retval > 0) {
1784                 int ret;
1785                 unsigned int status;
1786
1787                 if (unlikely(retval != map->m_len)) {
1788                         ext4_warning(inode->i_sb,
1789                                      "ES len assertion failed for inode "
1790                                      "%lu: retval %d != map->m_len %d",
1791                                      inode->i_ino, retval, map->m_len);
1792                         WARN_ON(1);
1793                 }
1794
1795                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1796                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1797                 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1798                                             map->m_pblk, status);
1799                 if (ret != 0)
1800                         retval = ret;
1801         }
1802
1803 out_unlock:
1804         up_read((&EXT4_I(inode)->i_data_sem));
1805
1806         return retval;
1807 }
1808
1809 /*
1810  * This is a special get_block_t callback which is used by
1811  * ext4_da_write_begin().  It will either return mapped block or
1812  * reserve space for a single block.
1813  *
1814  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1815  * We also have b_blocknr = -1 and b_bdev initialized properly
1816  *
1817  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1818  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1819  * initialized properly.
1820  */
1821 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1822                            struct buffer_head *bh, int create)
1823 {
1824         struct ext4_map_blocks map;
1825         int ret = 0;
1826
1827         BUG_ON(create == 0);
1828         BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1829
1830         map.m_lblk = iblock;
1831         map.m_len = 1;
1832
1833         /*
1834          * first, we need to know whether the block is allocated already
1835          * preallocated blocks are unmapped but should treated
1836          * the same as allocated blocks.
1837          */
1838         ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1839         if (ret <= 0)
1840                 return ret;
1841
1842         map_bh(bh, inode->i_sb, map.m_pblk);
1843         ext4_update_bh_state(bh, map.m_flags);
1844
1845         if (buffer_unwritten(bh)) {
1846                 /* A delayed write to unwritten bh should be marked
1847                  * new and mapped.  Mapped ensures that we don't do
1848                  * get_block multiple times when we write to the same
1849                  * offset and new ensures that we do proper zero out
1850                  * for partial write.
1851                  */
1852                 set_buffer_new(bh);
1853                 set_buffer_mapped(bh);
1854         }
1855         return 0;
1856 }
1857
1858 static int bget_one(handle_t *handle, struct inode *inode,
1859                     struct buffer_head *bh)
1860 {
1861         get_bh(bh);
1862         return 0;
1863 }
1864
1865 static int bput_one(handle_t *handle, struct inode *inode,
1866                     struct buffer_head *bh)
1867 {
1868         put_bh(bh);
1869         return 0;
1870 }
1871
1872 static int __ext4_journalled_writepage(struct page *page,
1873                                        unsigned int len)
1874 {
1875         struct address_space *mapping = page->mapping;
1876         struct inode *inode = mapping->host;
1877         struct buffer_head *page_bufs = NULL;
1878         handle_t *handle = NULL;
1879         int ret = 0, err = 0;
1880         int inline_data = ext4_has_inline_data(inode);
1881         struct buffer_head *inode_bh = NULL;
1882
1883         ClearPageChecked(page);
1884
1885         if (inline_data) {
1886                 BUG_ON(page->index != 0);
1887                 BUG_ON(len > ext4_get_max_inline_size(inode));
1888                 inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1889                 if (inode_bh == NULL)
1890                         goto out;
1891         } else {
1892                 page_bufs = page_buffers(page);
1893                 if (!page_bufs) {
1894                         BUG();
1895                         goto out;
1896                 }
1897                 ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1898                                        NULL, bget_one);
1899         }
1900         /*
1901          * We need to release the page lock before we start the
1902          * journal, so grab a reference so the page won't disappear
1903          * out from under us.
1904          */
1905         get_page(page);
1906         unlock_page(page);
1907
1908         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1909                                     ext4_writepage_trans_blocks(inode));
1910         if (IS_ERR(handle)) {
1911                 ret = PTR_ERR(handle);
1912                 put_page(page);
1913                 goto out_no_pagelock;
1914         }
1915         BUG_ON(!ext4_handle_valid(handle));
1916
1917         lock_page(page);
1918         put_page(page);
1919         if (page->mapping != mapping) {
1920                 /* The page got truncated from under us */
1921                 ext4_journal_stop(handle);
1922                 ret = 0;
1923                 goto out;
1924         }
1925
1926         if (inline_data) {
1927                 ret = ext4_mark_inode_dirty(handle, inode);
1928         } else {
1929                 ret = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1930                                              NULL, do_journal_get_write_access);
1931
1932                 err = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1933                                              NULL, write_end_fn);
1934         }
1935         if (ret == 0)
1936                 ret = err;
1937         err = ext4_jbd2_inode_add_write(handle, inode, page_offset(page), len);
1938         if (ret == 0)
1939                 ret = err;
1940         EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1941         err = ext4_journal_stop(handle);
1942         if (!ret)
1943                 ret = err;
1944
1945         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1946 out:
1947         unlock_page(page);
1948 out_no_pagelock:
1949         if (!inline_data && page_bufs)
1950                 ext4_walk_page_buffers(NULL, inode, page_bufs, 0, len,
1951                                        NULL, bput_one);
1952         brelse(inode_bh);
1953         return ret;
1954 }
1955
1956 /*
1957  * Note that we don't need to start a transaction unless we're journaling data
1958  * because we should have holes filled from ext4_page_mkwrite(). We even don't
1959  * need to file the inode to the transaction's list in ordered mode because if
1960  * we are writing back data added by write(), the inode is already there and if
1961  * we are writing back data modified via mmap(), no one guarantees in which
1962  * transaction the data will hit the disk. In case we are journaling data, we
1963  * cannot start transaction directly because transaction start ranks above page
1964  * lock so we have to do some magic.
1965  *
1966  * This function can get called via...
1967  *   - ext4_writepages after taking page lock (have journal handle)
1968  *   - journal_submit_inode_data_buffers (no journal handle)
1969  *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1970  *   - grab_page_cache when doing write_begin (have journal handle)
1971  *
1972  * We don't do any block allocation in this function. If we have page with
1973  * multiple blocks we need to write those buffer_heads that are mapped. This
1974  * is important for mmaped based write. So if we do with blocksize 1K
1975  * truncate(f, 1024);
1976  * a = mmap(f, 0, 4096);
1977  * a[0] = 'a';
1978  * truncate(f, 4096);
1979  * we have in the page first buffer_head mapped via page_mkwrite call back
1980  * but other buffer_heads would be unmapped but dirty (dirty done via the
1981  * do_wp_page). So writepage should write the first block. If we modify
1982  * the mmap area beyond 1024 we will again get a page_fault and the
1983  * page_mkwrite callback will do the block allocation and mark the
1984  * buffer_heads mapped.
1985  *
1986  * We redirty the page if we have any buffer_heads that is either delay or
1987  * unwritten in the page.
1988  *
1989  * We can get recursively called as show below.
1990  *
1991  *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1992  *              ext4_writepage()
1993  *
1994  * But since we don't do any block allocation we should not deadlock.
1995  * Page also have the dirty flag cleared so we don't get recurive page_lock.
1996  */
1997 static int ext4_writepage(struct page *page,
1998                           struct writeback_control *wbc)
1999 {
2000         int ret = 0;
2001         loff_t size;
2002         unsigned int len;
2003         struct buffer_head *page_bufs = NULL;
2004         struct inode *inode = page->mapping->host;
2005         struct ext4_io_submit io_submit;
2006         bool keep_towrite = false;
2007
2008         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
2009                 inode->i_mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
2010                 unlock_page(page);
2011                 return -EIO;
2012         }
2013
2014         trace_ext4_writepage(page);
2015         size = i_size_read(inode);
2016         if (page->index == size >> PAGE_SHIFT &&
2017             !ext4_verity_in_progress(inode))
2018                 len = size & ~PAGE_MASK;
2019         else
2020                 len = PAGE_SIZE;
2021
2022         page_bufs = page_buffers(page);
2023         /*
2024          * We cannot do block allocation or other extent handling in this
2025          * function. If there are buffers needing that, we have to redirty
2026          * the page. But we may reach here when we do a journal commit via
2027          * journal_submit_inode_data_buffers() and in that case we must write
2028          * allocated buffers to achieve data=ordered mode guarantees.
2029          *
2030          * Also, if there is only one buffer per page (the fs block
2031          * size == the page size), if one buffer needs block
2032          * allocation or needs to modify the extent tree to clear the
2033          * unwritten flag, we know that the page can't be written at
2034          * all, so we might as well refuse the write immediately.
2035          * Unfortunately if the block size != page size, we can't as
2036          * easily detect this case using ext4_walk_page_buffers(), but
2037          * for the extremely common case, this is an optimization that
2038          * skips a useless round trip through ext4_bio_write_page().
2039          */
2040         if (ext4_walk_page_buffers(NULL, inode, page_bufs, 0, len, NULL,
2041                                    ext4_bh_delay_or_unwritten)) {
2042                 redirty_page_for_writepage(wbc, page);
2043                 if ((current->flags & PF_MEMALLOC) ||
2044                     (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2045                         /*
2046                          * For memory cleaning there's no point in writing only
2047                          * some buffers. So just bail out. Warn if we came here
2048                          * from direct reclaim.
2049                          */
2050                         WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2051                                                         == PF_MEMALLOC);
2052                         unlock_page(page);
2053                         return 0;
2054                 }
2055                 keep_towrite = true;
2056         }
2057
2058         if (PageChecked(page) && ext4_should_journal_data(inode))
2059                 /*
2060                  * It's mmapped pagecache.  Add buffers and journal it.  There
2061                  * doesn't seem much point in redirtying the page here.
2062                  */
2063                 return __ext4_journalled_writepage(page, len);
2064
2065         ext4_io_submit_init(&io_submit, wbc);
2066         io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2067         if (!io_submit.io_end) {
2068                 redirty_page_for_writepage(wbc, page);
2069                 unlock_page(page);
2070                 return -ENOMEM;
2071         }
2072         ret = ext4_bio_write_page(&io_submit, page, len, keep_towrite);
2073         ext4_io_submit(&io_submit);
2074         /* Drop io_end reference we got from init */
2075         ext4_put_io_end_defer(io_submit.io_end);
2076         return ret;
2077 }
2078
2079 static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2080 {
2081         int len;
2082         loff_t size;
2083         int err;
2084
2085         BUG_ON(page->index != mpd->first_page);
2086         clear_page_dirty_for_io(page);
2087         /*
2088          * We have to be very careful here!  Nothing protects writeback path
2089          * against i_size changes and the page can be writeably mapped into
2090          * page tables. So an application can be growing i_size and writing
2091          * data through mmap while writeback runs. clear_page_dirty_for_io()
2092          * write-protects our page in page tables and the page cannot get
2093          * written to again until we release page lock. So only after
2094          * clear_page_dirty_for_io() we are safe to sample i_size for
2095          * ext4_bio_write_page() to zero-out tail of the written page. We rely
2096          * on the barrier provided by TestClearPageDirty in
2097          * clear_page_dirty_for_io() to make sure i_size is really sampled only
2098          * after page tables are updated.
2099          */
2100         size = i_size_read(mpd->inode);
2101         if (page->index == size >> PAGE_SHIFT &&
2102             !ext4_verity_in_progress(mpd->inode))
2103                 len = size & ~PAGE_MASK;
2104         else
2105                 len = PAGE_SIZE;
2106         err = ext4_bio_write_page(&mpd->io_submit, page, len, false);
2107         if (!err)
2108                 mpd->wbc->nr_to_write--;
2109         mpd->first_page++;
2110
2111         return err;
2112 }
2113
2114 #define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
2115
2116 /*
2117  * mballoc gives us at most this number of blocks...
2118  * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2119  * The rest of mballoc seems to handle chunks up to full group size.
2120  */
2121 #define MAX_WRITEPAGES_EXTENT_LEN 2048
2122
2123 /*
2124  * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2125  *
2126  * @mpd - extent of blocks
2127  * @lblk - logical number of the block in the file
2128  * @bh - buffer head we want to add to the extent
2129  *
2130  * The function is used to collect contig. blocks in the same state. If the
2131  * buffer doesn't require mapping for writeback and we haven't started the
2132  * extent of buffers to map yet, the function returns 'true' immediately - the
2133  * caller can write the buffer right away. Otherwise the function returns true
2134  * if the block has been added to the extent, false if the block couldn't be
2135  * added.
2136  */
2137 static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2138                                    struct buffer_head *bh)
2139 {
2140         struct ext4_map_blocks *map = &mpd->map;
2141
2142         /* Buffer that doesn't need mapping for writeback? */
2143         if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2144             (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2145                 /* So far no extent to map => we write the buffer right away */
2146                 if (map->m_len == 0)
2147                         return true;
2148                 return false;
2149         }
2150
2151         /* First block in the extent? */
2152         if (map->m_len == 0) {
2153                 /* We cannot map unless handle is started... */
2154                 if (!mpd->do_map)
2155                         return false;
2156                 map->m_lblk = lblk;
2157                 map->m_len = 1;
2158                 map->m_flags = bh->b_state & BH_FLAGS;
2159                 return true;
2160         }
2161
2162         /* Don't go larger than mballoc is willing to allocate */
2163         if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2164                 return false;
2165
2166         /* Can we merge the block to our big extent? */
2167         if (lblk == map->m_lblk + map->m_len &&
2168             (bh->b_state & BH_FLAGS) == map->m_flags) {
2169                 map->m_len++;
2170                 return true;
2171         }
2172         return false;
2173 }
2174
2175 /*
2176  * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2177  *
2178  * @mpd - extent of blocks for mapping
2179  * @head - the first buffer in the page
2180  * @bh - buffer we should start processing from
2181  * @lblk - logical number of the block in the file corresponding to @bh
2182  *
2183  * Walk through page buffers from @bh upto @head (exclusive) and either submit
2184  * the page for IO if all buffers in this page were mapped and there's no
2185  * accumulated extent of buffers to map or add buffers in the page to the
2186  * extent of buffers to map. The function returns 1 if the caller can continue
2187  * by processing the next page, 0 if it should stop adding buffers to the
2188  * extent to map because we cannot extend it anymore. It can also return value
2189  * < 0 in case of error during IO submission.
2190  */
2191 static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2192                                    struct buffer_head *head,
2193                                    struct buffer_head *bh,
2194                                    ext4_lblk_t lblk)
2195 {
2196         struct inode *inode = mpd->inode;
2197         int err;
2198         ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
2199                                                         >> inode->i_blkbits;
2200
2201         if (ext4_verity_in_progress(inode))
2202                 blocks = EXT_MAX_BLOCKS;
2203
2204         do {
2205                 BUG_ON(buffer_locked(bh));
2206
2207                 if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2208                         /* Found extent to map? */
2209                         if (mpd->map.m_len)
2210                                 return 0;
2211                         /* Buffer needs mapping and handle is not started? */
2212                         if (!mpd->do_map)
2213                                 return 0;
2214                         /* Everything mapped so far and we hit EOF */
2215                         break;
2216                 }
2217         } while (lblk++, (bh = bh->b_this_page) != head);
2218         /* So far everything mapped? Submit the page for IO. */
2219         if (mpd->map.m_len == 0) {
2220                 err = mpage_submit_page(mpd, head->b_page);
2221                 if (err < 0)
2222                         return err;
2223         }
2224         if (lblk >= blocks) {
2225                 mpd->scanned_until_end = 1;
2226                 return 0;
2227         }
2228         return 1;
2229 }
2230
2231 /*
2232  * mpage_process_page - update page buffers corresponding to changed extent and
2233  *                     may submit fully mapped page for IO
2234  *
2235  * @mpd         - description of extent to map, on return next extent to map
2236  * @m_lblk      - logical block mapping.
2237  * @m_pblk      - corresponding physical mapping.
2238  * @map_bh      - determines on return whether this page requires any further
2239  *                mapping or not.
2240  * Scan given page buffers corresponding to changed extent and update buffer
2241  * state according to new extent state.
2242  * We map delalloc buffers to their physical location, clear unwritten bits.
2243  * If the given page is not fully mapped, we update @map to the next extent in
2244  * the given page that needs mapping & return @map_bh as true.
2245  */
2246 static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
2247                               ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
2248                               bool *map_bh)
2249 {
2250         struct buffer_head *head, *bh;
2251         ext4_io_end_t *io_end = mpd->io_submit.io_end;
2252         ext4_lblk_t lblk = *m_lblk;
2253         ext4_fsblk_t pblock = *m_pblk;
2254         int err = 0;
2255         int blkbits = mpd->inode->i_blkbits;
2256         ssize_t io_end_size = 0;
2257         struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2258
2259         bh = head = page_buffers(page);
2260         do {
2261                 if (lblk < mpd->map.m_lblk)
2262                         continue;
2263                 if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2264                         /*
2265                          * Buffer after end of mapped extent.
2266                          * Find next buffer in the page to map.
2267                          */
2268                         mpd->map.m_len = 0;
2269                         mpd->map.m_flags = 0;
2270                         io_end_vec->size += io_end_size;
2271                         io_end_size = 0;
2272
2273                         err = mpage_process_page_bufs(mpd, head, bh, lblk);
2274                         if (err > 0)
2275                                 err = 0;
2276                         if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2277                                 io_end_vec = ext4_alloc_io_end_vec(io_end);
2278                                 if (IS_ERR(io_end_vec)) {
2279                                         err = PTR_ERR(io_end_vec);
2280                                         goto out;
2281                                 }
2282                                 io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
2283                         }
2284                         *map_bh = true;
2285                         goto out;
2286                 }
2287                 if (buffer_delay(bh)) {
2288                         clear_buffer_delay(bh);
2289                         bh->b_blocknr = pblock++;
2290                 }
2291                 clear_buffer_unwritten(bh);
2292                 io_end_size += (1 << blkbits);
2293         } while (lblk++, (bh = bh->b_this_page) != head);
2294
2295         io_end_vec->size += io_end_size;
2296         io_end_size = 0;
2297         *map_bh = false;
2298 out:
2299         *m_lblk = lblk;
2300         *m_pblk = pblock;
2301         return err;
2302 }
2303
2304 /*
2305  * mpage_map_buffers - update buffers corresponding to changed extent and
2306  *                     submit fully mapped pages for IO
2307  *
2308  * @mpd - description of extent to map, on return next extent to map
2309  *
2310  * Scan buffers corresponding to changed extent (we expect corresponding pages
2311  * to be already locked) and update buffer state according to new extent state.
2312  * We map delalloc buffers to their physical location, clear unwritten bits,
2313  * and mark buffers as uninit when we perform writes to unwritten extents
2314  * and do extent conversion after IO is finished. If the last page is not fully
2315  * mapped, we update @map to the next extent in the last page that needs
2316  * mapping. Otherwise we submit the page for IO.
2317  */
2318 static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2319 {
2320         struct pagevec pvec;
2321         int nr_pages, i;
2322         struct inode *inode = mpd->inode;
2323         int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2324         pgoff_t start, end;
2325         ext4_lblk_t lblk;
2326         ext4_fsblk_t pblock;
2327         int err;
2328         bool map_bh = false;
2329
2330         start = mpd->map.m_lblk >> bpp_bits;
2331         end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2332         lblk = start << bpp_bits;
2333         pblock = mpd->map.m_pblk;
2334
2335         pagevec_init(&pvec);
2336         while (start <= end) {
2337                 nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
2338                                                 &start, end);
2339                 if (nr_pages == 0)
2340                         break;
2341                 for (i = 0; i < nr_pages; i++) {
2342                         struct page *page = pvec.pages[i];
2343
2344                         err = mpage_process_page(mpd, page, &lblk, &pblock,
2345                                                  &map_bh);
2346                         /*
2347                          * If map_bh is true, means page may require further bh
2348                          * mapping, or maybe the page was submitted for IO.
2349                          * So we return to call further extent mapping.
2350                          */
2351                         if (err < 0 || map_bh)
2352                                 goto out;
2353                         /* Page fully mapped - let IO run! */
2354                         err = mpage_submit_page(mpd, page);
2355                         if (err < 0)
2356                                 goto out;
2357                 }
2358                 pagevec_release(&pvec);
2359         }
2360         /* Extent fully mapped and matches with page boundary. We are done. */
2361         mpd->map.m_len = 0;
2362         mpd->map.m_flags = 0;
2363         return 0;
2364 out:
2365         pagevec_release(&pvec);
2366         return err;
2367 }
2368
2369 static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2370 {
2371         struct inode *inode = mpd->inode;
2372         struct ext4_map_blocks *map = &mpd->map;
2373         int get_blocks_flags;
2374         int err, dioread_nolock;
2375
2376         trace_ext4_da_write_pages_extent(inode, map);
2377         /*
2378          * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2379          * to convert an unwritten extent to be initialized (in the case
2380          * where we have written into one or more preallocated blocks).  It is
2381          * possible that we're going to need more metadata blocks than
2382          * previously reserved. However we must not fail because we're in
2383          * writeback and there is nothing we can do about it so it might result
2384          * in data loss.  So use reserved blocks to allocate metadata if
2385          * possible.
2386          *
2387          * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2388          * the blocks in question are delalloc blocks.  This indicates
2389          * that the blocks and quotas has already been checked when
2390          * the data was copied into the page cache.
2391          */
2392         get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2393                            EXT4_GET_BLOCKS_METADATA_NOFAIL |
2394                            EXT4_GET_BLOCKS_IO_SUBMIT;
2395         dioread_nolock = ext4_should_dioread_nolock(inode);
2396         if (dioread_nolock)
2397                 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2398         if (map->m_flags & BIT(BH_Delay))
2399                 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2400
2401         err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2402         if (err < 0)
2403                 return err;
2404         if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2405                 if (!mpd->io_submit.io_end->handle &&
2406                     ext4_handle_valid(handle)) {
2407                         mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2408                         handle->h_rsv_handle = NULL;
2409                 }
2410                 ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2411         }
2412
2413         BUG_ON(map->m_len == 0);
2414         return 0;
2415 }
2416
2417 /*
2418  * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2419  *                               mpd->len and submit pages underlying it for IO
2420  *
2421  * @handle - handle for journal operations
2422  * @mpd - extent to map
2423  * @give_up_on_write - we set this to true iff there is a fatal error and there
2424  *                     is no hope of writing the data. The caller should discard
2425  *                     dirty pages to avoid infinite loops.
2426  *
2427  * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2428  * delayed, blocks are allocated, if it is unwritten, we may need to convert
2429  * them to initialized or split the described range from larger unwritten
2430  * extent. Note that we need not map all the described range since allocation
2431  * can return less blocks or the range is covered by more unwritten extents. We
2432  * cannot map more because we are limited by reserved transaction credits. On
2433  * the other hand we always make sure that the last touched page is fully
2434  * mapped so that it can be written out (and thus forward progress is
2435  * guaranteed). After mapping we submit all mapped pages for IO.
2436  */
2437 static int mpage_map_and_submit_extent(handle_t *handle,
2438                                        struct mpage_da_data *mpd,
2439                                        bool *give_up_on_write)
2440 {
2441         struct inode *inode = mpd->inode;
2442         struct ext4_map_blocks *map = &mpd->map;
2443         int err;
2444         loff_t disksize;
2445         int progress = 0;
2446         ext4_io_end_t *io_end = mpd->io_submit.io_end;
2447         struct ext4_io_end_vec *io_end_vec;
2448
2449         io_end_vec = ext4_alloc_io_end_vec(io_end);
2450         if (IS_ERR(io_end_vec))
2451                 return PTR_ERR(io_end_vec);
2452         io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2453         do {
2454                 err = mpage_map_one_extent(handle, mpd);
2455                 if (err < 0) {
2456                         struct super_block *sb = inode->i_sb;
2457
2458                         if (ext4_forced_shutdown(EXT4_SB(sb)) ||
2459                             ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
2460                                 goto invalidate_dirty_pages;
2461                         /*
2462                          * Let the uper layers retry transient errors.
2463                          * In the case of ENOSPC, if ext4_count_free_blocks()
2464                          * is non-zero, a commit should free up blocks.
2465                          */
2466                         if ((err == -ENOMEM) ||
2467                             (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2468                                 if (progress)
2469                                         goto update_disksize;
2470                                 return err;
2471                         }
2472                         ext4_msg(sb, KERN_CRIT,
2473                                  "Delayed block allocation failed for "
2474                                  "inode %lu at logical offset %llu with"
2475                                  " max blocks %u with error %d",
2476                                  inode->i_ino,
2477                                  (unsigned long long)map->m_lblk,
2478                                  (unsigned)map->m_len, -err);
2479                         ext4_msg(sb, KERN_CRIT,
2480                                  "This should not happen!! Data will "
2481                                  "be lost\n");
2482                         if (err == -ENOSPC)
2483                                 ext4_print_free_blocks(inode);
2484                 invalidate_dirty_pages:
2485                         *give_up_on_write = true;
2486                         return err;
2487                 }
2488                 progress = 1;
2489                 /*
2490                  * Update buffer state, submit mapped pages, and get us new
2491                  * extent to map
2492                  */
2493                 err = mpage_map_and_submit_buffers(mpd);
2494                 if (err < 0)
2495                         goto update_disksize;
2496         } while (map->m_len);
2497
2498 update_disksize:
2499         /*
2500          * Update on-disk size after IO is submitted.  Races with
2501          * truncate are avoided by checking i_size under i_data_sem.
2502          */
2503         disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2504         if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2505                 int err2;
2506                 loff_t i_size;
2507
2508                 down_write(&EXT4_I(inode)->i_data_sem);
2509                 i_size = i_size_read(inode);
2510                 if (disksize > i_size)
2511                         disksize = i_size;
2512                 if (disksize > EXT4_I(inode)->i_disksize)
2513                         EXT4_I(inode)->i_disksize = disksize;
2514                 up_write(&EXT4_I(inode)->i_data_sem);
2515                 err2 = ext4_mark_inode_dirty(handle, inode);
2516                 if (err2) {
2517                         ext4_error_err(inode->i_sb, -err2,
2518                                        "Failed to mark inode %lu dirty",
2519                                        inode->i_ino);
2520                 }
2521                 if (!err)
2522                         err = err2;
2523         }
2524         return err;
2525 }
2526
2527 /*
2528  * Calculate the total number of credits to reserve for one writepages
2529  * iteration. This is called from ext4_writepages(). We map an extent of
2530  * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2531  * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2532  * bpp - 1 blocks in bpp different extents.
2533  */
2534 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2535 {
2536         int bpp = ext4_journal_blocks_per_page(inode);
2537
2538         return ext4_meta_trans_blocks(inode,
2539                                 MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2540 }
2541
2542 /*
2543  * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2544  *                               and underlying extent to map
2545  *
2546  * @mpd - where to look for pages
2547  *
2548  * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2549  * IO immediately. When we find a page which isn't mapped we start accumulating
2550  * extent of buffers underlying these pages that needs mapping (formed by
2551  * either delayed or unwritten buffers). We also lock the pages containing
2552  * these buffers. The extent found is returned in @mpd structure (starting at
2553  * mpd->lblk with length mpd->len blocks).
2554  *
2555  * Note that this function can attach bios to one io_end structure which are
2556  * neither logically nor physically contiguous. Although it may seem as an
2557  * unnecessary complication, it is actually inevitable in blocksize < pagesize
2558  * case as we need to track IO to all buffers underlying a page in one io_end.
2559  */
2560 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2561 {
2562         struct address_space *mapping = mpd->inode->i_mapping;
2563         struct pagevec pvec;
2564         unsigned int nr_pages;
2565         long left = mpd->wbc->nr_to_write;
2566         pgoff_t index = mpd->first_page;
2567         pgoff_t end = mpd->last_page;
2568         xa_mark_t tag;
2569         int i, err = 0;
2570         int blkbits = mpd->inode->i_blkbits;
2571         ext4_lblk_t lblk;
2572         struct buffer_head *head;
2573
2574         if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2575                 tag = PAGECACHE_TAG_TOWRITE;
2576         else
2577                 tag = PAGECACHE_TAG_DIRTY;
2578
2579         pagevec_init(&pvec);
2580         mpd->map.m_len = 0;
2581         mpd->next_page = index;
2582         while (index <= end) {
2583                 nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
2584                                 tag);
2585                 if (nr_pages == 0)
2586                         break;
2587
2588                 for (i = 0; i < nr_pages; i++) {
2589                         struct page *page = pvec.pages[i];
2590
2591                         /*
2592                          * Accumulated enough dirty pages? This doesn't apply
2593                          * to WB_SYNC_ALL mode. For integrity sync we have to
2594                          * keep going because someone may be concurrently
2595                          * dirtying pages, and we might have synced a lot of
2596                          * newly appeared dirty pages, but have not synced all
2597                          * of the old dirty pages.
2598                          */
2599                         if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2600                                 goto out;
2601
2602                         /* If we can't merge this page, we are done. */
2603                         if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2604                                 goto out;
2605
2606                         lock_page(page);
2607                         /*
2608                          * If the page is no longer dirty, or its mapping no
2609                          * longer corresponds to inode we are writing (which
2610                          * means it has been truncated or invalidated), or the
2611                          * page is already under writeback and we are not doing
2612                          * a data integrity writeback, skip the page
2613                          */
2614                         if (!PageDirty(page) ||
2615                             (PageWriteback(page) &&
2616                              (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2617                             unlikely(page->mapping != mapping)) {
2618                                 unlock_page(page);
2619                                 continue;
2620                         }
2621
2622                         wait_on_page_writeback(page);
2623                         BUG_ON(PageWriteback(page));
2624
2625                         if (mpd->map.m_len == 0)
2626                                 mpd->first_page = page->index;
2627                         mpd->next_page = page->index + 1;
2628                         /* Add all dirty buffers to mpd */
2629                         lblk = ((ext4_lblk_t)page->index) <<
2630                                 (PAGE_SHIFT - blkbits);
2631                         head = page_buffers(page);
2632                         err = mpage_process_page_bufs(mpd, head, head, lblk);
2633                         if (err <= 0)
2634                                 goto out;
2635                         err = 0;
2636                         left--;
2637                 }
2638                 pagevec_release(&pvec);
2639                 cond_resched();
2640         }
2641         mpd->scanned_until_end = 1;
2642         return 0;
2643 out:
2644         pagevec_release(&pvec);
2645         return err;
2646 }
2647
2648 static int ext4_writepages(struct address_space *mapping,
2649                            struct writeback_control *wbc)
2650 {
2651         pgoff_t writeback_index = 0;
2652         long nr_to_write = wbc->nr_to_write;
2653         int range_whole = 0;
2654         int cycled = 1;
2655         handle_t *handle = NULL;
2656         struct mpage_da_data mpd;
2657         struct inode *inode = mapping->host;
2658         int needed_blocks, rsv_blocks = 0, ret = 0;
2659         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2660         struct blk_plug plug;
2661         bool give_up_on_write = false;
2662
2663         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2664                 return -EIO;
2665
2666         percpu_down_read(&sbi->s_writepages_rwsem);
2667         trace_ext4_writepages(inode, wbc);
2668
2669         /*
2670          * No pages to write? This is mainly a kludge to avoid starting
2671          * a transaction for special inodes like journal inode on last iput()
2672          * because that could violate lock ordering on umount
2673          */
2674         if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2675                 goto out_writepages;
2676
2677         if (ext4_should_journal_data(inode)) {
2678                 ret = generic_writepages(mapping, wbc);
2679                 goto out_writepages;
2680         }
2681
2682         /*
2683          * If the filesystem has aborted, it is read-only, so return
2684          * right away instead of dumping stack traces later on that
2685          * will obscure the real source of the problem.  We test
2686          * EXT4_MF_FS_ABORTED instead of sb->s_flag's SB_RDONLY because
2687          * the latter could be true if the filesystem is mounted
2688          * read-only, and in that case, ext4_writepages should
2689          * *never* be called, so if that ever happens, we would want
2690          * the stack trace.
2691          */
2692         if (unlikely(ext4_forced_shutdown(EXT4_SB(mapping->host->i_sb)) ||
2693                      ext4_test_mount_flag(inode->i_sb, EXT4_MF_FS_ABORTED))) {
2694                 ret = -EROFS;
2695                 goto out_writepages;
2696         }
2697
2698         /*
2699          * If we have inline data and arrive here, it means that
2700          * we will soon create the block for the 1st page, so
2701          * we'd better clear the inline data here.
2702          */
2703         if (ext4_has_inline_data(inode)) {
2704                 /* Just inode will be modified... */
2705                 handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2706                 if (IS_ERR(handle)) {
2707                         ret = PTR_ERR(handle);
2708                         goto out_writepages;
2709                 }
2710                 BUG_ON(ext4_test_inode_state(inode,
2711                                 EXT4_STATE_MAY_INLINE_DATA));
2712                 ext4_destroy_inline_data(handle, inode);
2713                 ext4_journal_stop(handle);
2714         }
2715
2716         if (ext4_should_dioread_nolock(inode)) {
2717                 /*
2718                  * We may need to convert up to one extent per block in
2719                  * the page and we may dirty the inode.
2720                  */
2721                 rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
2722                                                 PAGE_SIZE >> inode->i_blkbits);
2723         }
2724
2725         if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2726                 range_whole = 1;
2727
2728         if (wbc->range_cyclic) {
2729                 writeback_index = mapping->writeback_index;
2730                 if (writeback_index)
2731                         cycled = 0;
2732                 mpd.first_page = writeback_index;
2733                 mpd.last_page = -1;
2734         } else {
2735                 mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2736                 mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2737         }
2738
2739         mpd.inode = inode;
2740         mpd.wbc = wbc;
2741         ext4_io_submit_init(&mpd.io_submit, wbc);
2742 retry:
2743         if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2744                 tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2745         blk_start_plug(&plug);
2746
2747         /*
2748          * First writeback pages that don't need mapping - we can avoid
2749          * starting a transaction unnecessarily and also avoid being blocked
2750          * in the block layer on device congestion while having transaction
2751          * started.
2752          */
2753         mpd.do_map = 0;
2754         mpd.scanned_until_end = 0;
2755         mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2756         if (!mpd.io_submit.io_end) {
2757                 ret = -ENOMEM;
2758                 goto unplug;
2759         }
2760         ret = mpage_prepare_extent_to_map(&mpd);
2761         /* Unlock pages we didn't use */
2762         mpage_release_unused_pages(&mpd, false);
2763         /* Submit prepared bio */
2764         ext4_io_submit(&mpd.io_submit);
2765         ext4_put_io_end_defer(mpd.io_submit.io_end);
2766         mpd.io_submit.io_end = NULL;
2767         if (ret < 0)
2768                 goto unplug;
2769
2770         while (!mpd.scanned_until_end && wbc->nr_to_write > 0) {
2771                 /* For each extent of pages we use new io_end */
2772                 mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2773                 if (!mpd.io_submit.io_end) {
2774                         ret = -ENOMEM;
2775                         break;
2776                 }
2777
2778                 /*
2779                  * We have two constraints: We find one extent to map and we
2780                  * must always write out whole page (makes a difference when
2781                  * blocksize < pagesize) so that we don't block on IO when we
2782                  * try to write out the rest of the page. Journalled mode is
2783                  * not supported by delalloc.
2784                  */
2785                 BUG_ON(ext4_should_journal_data(inode));
2786                 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2787
2788                 /* start a new transaction */
2789                 handle = ext4_journal_start_with_reserve(inode,
2790                                 EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2791                 if (IS_ERR(handle)) {
2792                         ret = PTR_ERR(handle);
2793                         ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2794                                "%ld pages, ino %lu; err %d", __func__,
2795                                 wbc->nr_to_write, inode->i_ino, ret);
2796                         /* Release allocated io_end */
2797                         ext4_put_io_end(mpd.io_submit.io_end);
2798                         mpd.io_submit.io_end = NULL;
2799                         break;
2800                 }
2801                 mpd.do_map = 1;
2802
2803                 trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2804                 ret = mpage_prepare_extent_to_map(&mpd);
2805                 if (!ret && mpd.map.m_len)
2806                         ret = mpage_map_and_submit_extent(handle, &mpd,
2807                                         &give_up_on_write);
2808                 /*
2809                  * Caution: If the handle is synchronous,
2810                  * ext4_journal_stop() can wait for transaction commit
2811                  * to finish which may depend on writeback of pages to
2812                  * complete or on page lock to be released.  In that
2813                  * case, we have to wait until after we have
2814                  * submitted all the IO, released page locks we hold,
2815                  * and dropped io_end reference (for extent conversion
2816                  * to be able to complete) before stopping the handle.
2817                  */
2818                 if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2819                         ext4_journal_stop(handle);
2820                         handle = NULL;
2821                         mpd.do_map = 0;
2822                 }
2823                 /* Unlock pages we didn't use */
2824                 mpage_release_unused_pages(&mpd, give_up_on_write);
2825                 /* Submit prepared bio */
2826                 ext4_io_submit(&mpd.io_submit);
2827
2828                 /*
2829                  * Drop our io_end reference we got from init. We have
2830                  * to be careful and use deferred io_end finishing if
2831                  * we are still holding the transaction as we can
2832                  * release the last reference to io_end which may end
2833                  * up doing unwritten extent conversion.
2834                  */
2835                 if (handle) {
2836                         ext4_put_io_end_defer(mpd.io_submit.io_end);
2837                         ext4_journal_stop(handle);
2838                 } else
2839                         ext4_put_io_end(mpd.io_submit.io_end);
2840                 mpd.io_submit.io_end = NULL;
2841
2842                 if (ret == -ENOSPC && sbi->s_journal) {
2843                         /*
2844                          * Commit the transaction which would
2845                          * free blocks released in the transaction
2846                          * and try again
2847                          */
2848                         jbd2_journal_force_commit_nested(sbi->s_journal);
2849                         ret = 0;
2850                         continue;
2851                 }
2852                 /* Fatal error - ENOMEM, EIO... */
2853                 if (ret)
2854                         break;
2855         }
2856 unplug:
2857         blk_finish_plug(&plug);
2858         if (!ret && !cycled && wbc->nr_to_write > 0) {
2859                 cycled = 1;
2860                 mpd.last_page = writeback_index - 1;
2861                 mpd.first_page = 0;
2862                 goto retry;
2863         }
2864
2865         /* Update index */
2866         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2867                 /*
2868                  * Set the writeback_index so that range_cyclic
2869                  * mode will write it back later
2870                  */
2871                 mapping->writeback_index = mpd.first_page;
2872
2873 out_writepages:
2874         trace_ext4_writepages_result(inode, wbc, ret,
2875                                      nr_to_write - wbc->nr_to_write);
2876         percpu_up_read(&sbi->s_writepages_rwsem);
2877         return ret;
2878 }
2879
2880 static int ext4_dax_writepages(struct address_space *mapping,
2881                                struct writeback_control *wbc)
2882 {
2883         int ret;
2884         long nr_to_write = wbc->nr_to_write;
2885         struct inode *inode = mapping->host;
2886         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2887
2888         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2889                 return -EIO;
2890
2891         percpu_down_read(&sbi->s_writepages_rwsem);
2892         trace_ext4_writepages(inode, wbc);
2893
2894         ret = dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
2895         trace_ext4_writepages_result(inode, wbc, ret,
2896                                      nr_to_write - wbc->nr_to_write);
2897         percpu_up_read(&sbi->s_writepages_rwsem);
2898         return ret;
2899 }
2900
2901 static int ext4_nonda_switch(struct super_block *sb)
2902 {
2903         s64 free_clusters, dirty_clusters;
2904         struct ext4_sb_info *sbi = EXT4_SB(sb);
2905
2906         /*
2907          * switch to non delalloc mode if we are running low
2908          * on free block. The free block accounting via percpu
2909          * counters can get slightly wrong with percpu_counter_batch getting
2910          * accumulated on each CPU without updating global counters
2911          * Delalloc need an accurate free block accounting. So switch
2912          * to non delalloc when we are near to error range.
2913          */
2914         free_clusters =
2915                 percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2916         dirty_clusters =
2917                 percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2918         /*
2919          * Start pushing delalloc when 1/2 of free blocks are dirty.
2920          */
2921         if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2922                 try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2923
2924         if (2 * free_clusters < 3 * dirty_clusters ||
2925             free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2926                 /*
2927                  * free block count is less than 150% of dirty blocks
2928                  * or free blocks is less than watermark
2929                  */
2930                 return 1;
2931         }
2932         return 0;
2933 }
2934
2935 /* We always reserve for an inode update; the superblock could be there too */
2936 static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
2937 {
2938         if (likely(ext4_has_feature_large_file(inode->i_sb)))
2939                 return 1;
2940
2941         if (pos + len <= 0x7fffffffULL)
2942                 return 1;
2943
2944         /* We might need to update the superblock to set LARGE_FILE */
2945         return 2;
2946 }
2947
2948 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2949                                loff_t pos, unsigned len, unsigned flags,
2950                                struct page **pagep, void **fsdata)
2951 {
2952         int ret, retries = 0;
2953         struct page *page;
2954         pgoff_t index;
2955         struct inode *inode = mapping->host;
2956         handle_t *handle;
2957
2958         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2959                 return -EIO;
2960
2961         index = pos >> PAGE_SHIFT;
2962
2963         if (ext4_nonda_switch(inode->i_sb) || S_ISLNK(inode->i_mode) ||
2964             ext4_verity_in_progress(inode)) {
2965                 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2966                 return ext4_write_begin(file, mapping, pos,
2967                                         len, flags, pagep, fsdata);
2968         }
2969         *fsdata = (void *)0;
2970         trace_ext4_da_write_begin(inode, pos, len, flags);
2971
2972         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2973                 ret = ext4_da_write_inline_data_begin(mapping, inode,
2974                                                       pos, len, flags,
2975                                                       pagep, fsdata);
2976                 if (ret < 0)
2977                         return ret;
2978                 if (ret == 1)
2979                         return 0;
2980         }
2981
2982         /*
2983          * grab_cache_page_write_begin() can take a long time if the
2984          * system is thrashing due to memory pressure, or if the page
2985          * is being written back.  So grab it first before we start
2986          * the transaction handle.  This also allows us to allocate
2987          * the page (if needed) without using GFP_NOFS.
2988          */
2989 retry_grab:
2990         page = grab_cache_page_write_begin(mapping, index, flags);
2991         if (!page)
2992                 return -ENOMEM;
2993         unlock_page(page);
2994
2995         /*
2996          * With delayed allocation, we don't log the i_disksize update
2997          * if there is delayed block allocation. But we still need
2998          * to journalling the i_disksize update if writes to the end
2999          * of file which has an already mapped buffer.
3000          */
3001 retry_journal:
3002         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
3003                                 ext4_da_write_credits(inode, pos, len));
3004         if (IS_ERR(handle)) {
3005                 put_page(page);
3006                 return PTR_ERR(handle);
3007         }
3008
3009         lock_page(page);
3010         if (page->mapping != mapping) {
3011                 /* The page got truncated from under us */
3012                 unlock_page(page);
3013                 put_page(page);
3014                 ext4_journal_stop(handle);
3015                 goto retry_grab;
3016         }
3017         /* In case writeback began while the page was unlocked */
3018         wait_for_stable_page(page);
3019
3020 #ifdef CONFIG_FS_ENCRYPTION
3021         ret = ext4_block_write_begin(page, pos, len,
3022                                      ext4_da_get_block_prep);
3023 #else
3024         ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
3025 #endif
3026         if (ret < 0) {
3027                 unlock_page(page);
3028                 ext4_journal_stop(handle);
3029                 /*
3030                  * block_write_begin may have instantiated a few blocks
3031                  * outside i_size.  Trim these off again. Don't need
3032                  * i_size_read because we hold i_mutex.
3033                  */
3034                 if (pos + len > inode->i_size)
3035                         ext4_truncate_failed_write(inode);
3036
3037                 if (ret == -ENOSPC &&
3038                     ext4_should_retry_alloc(inode->i_sb, &retries))
3039                         goto retry_journal;
3040
3041                 put_page(page);
3042                 return ret;
3043         }
3044
3045         *pagep = page;
3046         return ret;
3047 }
3048
3049 /*
3050  * Check if we should update i_disksize
3051  * when write to the end of file but not require block allocation
3052  */
3053 static int ext4_da_should_update_i_disksize(struct page *page,
3054                                             unsigned long offset)
3055 {
3056         struct buffer_head *bh;
3057         struct inode *inode = page->mapping->host;
3058         unsigned int idx;
3059         int i;
3060
3061         bh = page_buffers(page);
3062         idx = offset >> inode->i_blkbits;
3063
3064         for (i = 0; i < idx; i++)
3065                 bh = bh->b_this_page;
3066
3067         if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3068                 return 0;
3069         return 1;
3070 }
3071
3072 static int ext4_da_write_end(struct file *file,
3073                              struct address_space *mapping,
3074                              loff_t pos, unsigned len, unsigned copied,
3075                              struct page *page, void *fsdata)
3076 {
3077         struct inode *inode = mapping->host;
3078         int ret = 0, ret2;
3079         handle_t *handle = ext4_journal_current_handle();
3080         loff_t new_i_size;
3081         unsigned long start, end;
3082         int write_mode = (int)(unsigned long)fsdata;
3083
3084         if (write_mode == FALL_BACK_TO_NONDELALLOC)
3085                 return ext4_write_end(file, mapping, pos,
3086                                       len, copied, page, fsdata);
3087
3088         trace_ext4_da_write_end(inode, pos, len, copied);
3089         start = pos & (PAGE_SIZE - 1);
3090         end = start + copied - 1;
3091
3092         /*
3093          * generic_write_end() will run mark_inode_dirty() if i_size
3094          * changes.  So let's piggyback the i_disksize mark_inode_dirty
3095          * into that.
3096          */
3097         new_i_size = pos + copied;
3098         if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
3099                 if (ext4_has_inline_data(inode) ||
3100                     ext4_da_should_update_i_disksize(page, end)) {
3101                         ext4_update_i_disksize(inode, new_i_size);
3102                         /* We need to mark inode dirty even if
3103                          * new_i_size is less that inode->i_size
3104                          * bu greater than i_disksize.(hint delalloc)
3105                          */
3106                         ret = ext4_mark_inode_dirty(handle, inode);
3107                 }
3108         }
3109
3110         if (write_mode != CONVERT_INLINE_DATA &&
3111             ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3112             ext4_has_inline_data(inode))
3113                 ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
3114                                                      page);
3115         else
3116                 ret2 = generic_write_end(file, mapping, pos, len, copied,
3117                                                         page, fsdata);
3118
3119         copied = ret2;
3120         if (ret2 < 0)
3121                 ret = ret2;
3122         ret2 = ext4_journal_stop(handle);
3123         if (unlikely(ret2 && !ret))
3124                 ret = ret2;
3125
3126         return ret ? ret : copied;
3127 }
3128
3129 /*
3130  * Force all delayed allocation blocks to be allocated for a given inode.
3131  */
3132 int ext4_alloc_da_blocks(struct inode *inode)
3133 {
3134         trace_ext4_alloc_da_blocks(inode);
3135
3136         if (!EXT4_I(inode)->i_reserved_data_blocks)
3137                 return 0;
3138
3139         /*
3140          * We do something simple for now.  The filemap_flush() will
3141          * also start triggering a write of the data blocks, which is
3142          * not strictly speaking necessary (and for users of
3143          * laptop_mode, not even desirable).  However, to do otherwise
3144          * would require replicating code paths in:
3145          *
3146          * ext4_writepages() ->
3147          *    write_cache_pages() ---> (via passed in callback function)
3148          *        __mpage_da_writepage() -->
3149          *           mpage_add_bh_to_extent()
3150          *           mpage_da_map_blocks()
3151          *
3152          * The problem is that write_cache_pages(), located in
3153          * mm/page-writeback.c, marks pages clean in preparation for
3154          * doing I/O, which is not desirable if we're not planning on
3155          * doing I/O at all.
3156          *
3157          * We could call write_cache_pages(), and then redirty all of
3158          * the pages by calling redirty_page_for_writepage() but that
3159          * would be ugly in the extreme.  So instead we would need to
3160          * replicate parts of the code in the above functions,
3161          * simplifying them because we wouldn't actually intend to
3162          * write out the pages, but rather only collect contiguous
3163          * logical block extents, call the multi-block allocator, and
3164          * then update the buffer heads with the block allocations.
3165          *
3166          * For now, though, we'll cheat by calling filemap_flush(),
3167          * which will map the blocks, and start the I/O, but not
3168          * actually wait for the I/O to complete.
3169          */
3170         return filemap_flush(inode->i_mapping);
3171 }
3172
3173 /*
3174  * bmap() is special.  It gets used by applications such as lilo and by
3175  * the swapper to find the on-disk block of a specific piece of data.
3176  *
3177  * Naturally, this is dangerous if the block concerned is still in the
3178  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3179  * filesystem and enables swap, then they may get a nasty shock when the
3180  * data getting swapped to that swapfile suddenly gets overwritten by
3181  * the original zero's written out previously to the journal and
3182  * awaiting writeback in the kernel's buffer cache.
3183  *
3184  * So, if we see any bmap calls here on a modified, data-journaled file,
3185  * take extra steps to flush any blocks which might be in the cache.
3186  */
3187 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3188 {
3189         struct inode *inode = mapping->host;
3190         journal_t *journal;
3191         int err;
3192
3193         /*
3194          * We can get here for an inline file via the FIBMAP ioctl
3195          */
3196         if (ext4_has_inline_data(inode))
3197                 return 0;
3198
3199         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3200                         test_opt(inode->i_sb, DELALLOC)) {
3201                 /*
3202                  * With delalloc we want to sync the file
3203                  * so that we can make sure we allocate
3204                  * blocks for file
3205                  */
3206                 filemap_write_and_wait(mapping);
3207         }
3208
3209         if (EXT4_JOURNAL(inode) &&
3210             ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3211                 /*
3212                  * This is a REALLY heavyweight approach, but the use of
3213                  * bmap on dirty files is expected to be extremely rare:
3214                  * only if we run lilo or swapon on a freshly made file
3215                  * do we expect this to happen.
3216                  *
3217                  * (bmap requires CAP_SYS_RAWIO so this does not
3218                  * represent an unprivileged user DOS attack --- we'd be
3219                  * in trouble if mortal users could trigger this path at
3220                  * will.)
3221                  *
3222                  * NB. EXT4_STATE_JDATA is not set on files other than
3223                  * regular files.  If somebody wants to bmap a directory
3224                  * or symlink and gets confused because the buffer
3225                  * hasn't yet been flushed to disk, they deserve
3226                  * everything they get.
3227                  */
3228
3229                 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3230                 journal = EXT4_JOURNAL(inode);
3231                 jbd2_journal_lock_updates(journal);
3232                 err = jbd2_journal_flush(journal, 0);
3233                 jbd2_journal_unlock_updates(journal);
3234
3235                 if (err)
3236                         return 0;
3237         }
3238
3239         return iomap_bmap(mapping, block, &ext4_iomap_ops);
3240 }
3241
3242 static int ext4_readpage(struct file *file, struct page *page)
3243 {
3244         int ret = -EAGAIN;
3245         struct inode *inode = page->mapping->host;
3246
3247         trace_ext4_readpage(page);
3248
3249         if (ext4_has_inline_data(inode))
3250                 ret = ext4_readpage_inline(inode, page);
3251
3252         if (ret == -EAGAIN)
3253                 return ext4_mpage_readpages(inode, NULL, page);
3254
3255         return ret;
3256 }
3257
3258 static void ext4_readahead(struct readahead_control *rac)
3259 {
3260         struct inode *inode = rac->mapping->host;
3261
3262         /* If the file has inline data, no need to do readahead. */
3263         if (ext4_has_inline_data(inode))
3264                 return;
3265
3266         ext4_mpage_readpages(inode, rac, NULL);
3267 }
3268
3269 static void ext4_invalidatepage(struct page *page, unsigned int offset,
3270                                 unsigned int length)
3271 {
3272         trace_ext4_invalidatepage(page, offset, length);
3273
3274         /* No journalling happens on data buffers when this function is used */
3275         WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
3276
3277         block_invalidatepage(page, offset, length);
3278 }
3279
3280 static int __ext4_journalled_invalidatepage(struct page *page,
3281                                             unsigned int offset,
3282                                             unsigned int length)
3283 {
3284         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3285
3286         trace_ext4_journalled_invalidatepage(page, offset, length);
3287
3288         /*
3289          * If it's a full truncate we just forget about the pending dirtying
3290          */
3291         if (offset == 0 && length == PAGE_SIZE)
3292                 ClearPageChecked(page);
3293
3294         return jbd2_journal_invalidatepage(journal, page, offset, length);
3295 }
3296
3297 /* Wrapper for aops... */
3298 static void ext4_journalled_invalidatepage(struct page *page,
3299                                            unsigned int offset,
3300                                            unsigned int length)
3301 {
3302         WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3303 }
3304
3305 static int ext4_releasepage(struct page *page, gfp_t wait)
3306 {
3307         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3308
3309         trace_ext4_releasepage(page);
3310
3311         /* Page has dirty journalled data -> cannot release */
3312         if (PageChecked(page))
3313                 return 0;
3314         if (journal)
3315                 return jbd2_journal_try_to_free_buffers(journal, page);
3316         else
3317                 return try_to_free_buffers(page);
3318 }
3319
3320 static bool ext4_inode_datasync_dirty(struct inode *inode)
3321 {
3322         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3323
3324         if (journal) {
3325                 if (jbd2_transaction_committed(journal,
3326                         EXT4_I(inode)->i_datasync_tid))
3327                         return false;
3328                 if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
3329                         return !list_empty(&EXT4_I(inode)->i_fc_list);
3330                 return true;
3331         }
3332
3333         /* Any metadata buffers to write? */
3334         if (!list_empty(&inode->i_mapping->private_list))
3335                 return true;
3336         return inode->i_state & I_DIRTY_DATASYNC;
3337 }
3338
3339 static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
3340                            struct ext4_map_blocks *map, loff_t offset,
3341                            loff_t length)
3342 {
3343         u8 blkbits = inode->i_blkbits;
3344
3345         /*
3346          * Writes that span EOF might trigger an I/O size update on completion,
3347          * so consider them to be dirty for the purpose of O_DSYNC, even if
3348          * there is no other metadata changes being made or are pending.
3349          */
3350         iomap->flags = 0;
3351         if (ext4_inode_datasync_dirty(inode) ||
3352             offset + length > i_size_read(inode))
3353                 iomap->flags |= IOMAP_F_DIRTY;
3354
3355         if (map->m_flags & EXT4_MAP_NEW)
3356                 iomap->flags |= IOMAP_F_NEW;
3357
3358         iomap->bdev = inode->i_sb->s_bdev;
3359         iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
3360         iomap->offset = (u64) map->m_lblk << blkbits;
3361         iomap->length = (u64) map->m_len << blkbits;
3362
3363         if ((map->m_flags & EXT4_MAP_MAPPED) &&
3364             !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3365                 iomap->flags |= IOMAP_F_MERGED;
3366
3367         /*
3368          * Flags passed to ext4_map_blocks() for direct I/O writes can result
3369          * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3370          * set. In order for any allocated unwritten extents to be converted
3371          * into written extents correctly within the ->end_io() handler, we
3372          * need to ensure that the iomap->type is set appropriately. Hence, the
3373          * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3374          * been set first.
3375          */
3376         if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3377                 iomap->type = IOMAP_UNWRITTEN;
3378                 iomap->addr = (u64) map->m_pblk << blkbits;
3379         } else if (map->m_flags & EXT4_MAP_MAPPED) {
3380                 iomap->type = IOMAP_MAPPED;
3381                 iomap->addr = (u64) map->m_pblk << blkbits;
3382         } else {
3383                 iomap->type = IOMAP_HOLE;
3384                 iomap->addr = IOMAP_NULL_ADDR;
3385         }
3386 }
3387
3388 static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
3389                             unsigned int flags)
3390 {
3391         handle_t *handle;
3392         u8 blkbits = inode->i_blkbits;
3393         int ret, dio_credits, m_flags = 0, retries = 0;
3394
3395         /*
3396          * Trim the mapping request to the maximum value that we can map at
3397          * once for direct I/O.
3398          */
3399         if (map->m_len > DIO_MAX_BLOCKS)
3400                 map->m_len = DIO_MAX_BLOCKS;
3401         dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
3402
3403 retry:
3404         /*
3405          * Either we allocate blocks and then don't get an unwritten extent, so
3406          * in that case we have reserved enough credits. Or, the blocks are
3407          * already allocated and unwritten. In that case, the extent conversion
3408          * fits into the credits as well.
3409          */
3410         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3411         if (IS_ERR(handle))
3412                 return PTR_ERR(handle);
3413
3414         /*
3415          * DAX and direct I/O are the only two operations that are currently
3416          * supported with IOMAP_WRITE.
3417          */
3418         WARN_ON(!IS_DAX(inode) && !(flags & IOMAP_DIRECT));
3419         if (IS_DAX(inode))
3420                 m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3421         /*
3422          * We use i_size instead of i_disksize here because delalloc writeback
3423          * can complete at any point during the I/O and subsequently push the
3424          * i_disksize out to i_size. This could be beyond where direct I/O is
3425          * happening and thus expose allocated blocks to direct I/O reads.
3426          */
3427         else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
3428                 m_flags = EXT4_GET_BLOCKS_CREATE;
3429         else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3430                 m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3431
3432         ret = ext4_map_blocks(handle, inode, map, m_flags);
3433
3434         /*
3435          * We cannot fill holes in indirect tree based inodes as that could
3436          * expose stale data in the case of a crash. Use the magic error code
3437          * to fallback to buffered I/O.
3438          */
3439         if (!m_flags && !ret)
3440                 ret = -ENOTBLK;
3441
3442         ext4_journal_stop(handle);
3443         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3444                 goto retry;
3445
3446         return ret;
3447 }
3448
3449
3450 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3451                 unsigned flags, struct iomap *iomap, struct iomap *srcmap)
3452 {
3453         int ret;
3454         struct ext4_map_blocks map;
3455         u8 blkbits = inode->i_blkbits;
3456
3457         if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3458                 return -EINVAL;
3459
3460         if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3461                 return -ERANGE;
3462
3463         /*
3464          * Calculate the first and last logical blocks respectively.
3465          */
3466         map.m_lblk = offset >> blkbits;
3467         map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3468                           EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3469
3470         if (flags & IOMAP_WRITE) {
3471                 /*
3472                  * We check here if the blocks are already allocated, then we
3473                  * don't need to start a journal txn and we can directly return
3474                  * the mapping information. This could boost performance
3475                  * especially in multi-threaded overwrite requests.
3476                  */
3477                 if (offset + length <= i_size_read(inode)) {
3478                         ret = ext4_map_blocks(NULL, inode, &map, 0);
3479                         if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
3480                                 goto out;
3481                 }
3482                 ret = ext4_iomap_alloc(inode, &map, flags);
3483         } else {
3484                 ret = ext4_map_blocks(NULL, inode, &map, 0);
3485         }
3486
3487         if (ret < 0)
3488                 return ret;
3489 out:
3490         ext4_set_iomap(inode, iomap, &map, offset, length);
3491
3492         return 0;
3493 }
3494
3495 static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3496                 loff_t length, unsigned flags, struct iomap *iomap,
3497                 struct iomap *srcmap)
3498 {
3499         int ret;
3500
3501         /*
3502          * Even for writes we don't need to allocate blocks, so just pretend
3503          * we are reading to save overhead of starting a transaction.
3504          */
3505         flags &= ~IOMAP_WRITE;
3506         ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3507         WARN_ON_ONCE(iomap->type != IOMAP_MAPPED);
3508         return ret;
3509 }
3510
3511 static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3512                           ssize_t written, unsigned flags, struct iomap *iomap)
3513 {
3514         /*
3515          * Check to see whether an error occurred while writing out the data to
3516          * the allocated blocks. If so, return the magic error code so that we
3517          * fallback to buffered I/O and attempt to complete the remainder of
3518          * the I/O. Any blocks that may have been allocated in preparation for
3519          * the direct I/O will be reused during buffered I/O.
3520          */
3521         if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
3522                 return -ENOTBLK;
3523
3524         return 0;
3525 }
3526
3527 const struct iomap_ops ext4_iomap_ops = {
3528         .iomap_begin            = ext4_iomap_begin,
3529         .iomap_end              = ext4_iomap_end,
3530 };
3531
3532 const struct iomap_ops ext4_iomap_overwrite_ops = {
3533         .iomap_begin            = ext4_iomap_overwrite_begin,
3534         .iomap_end              = ext4_iomap_end,
3535 };
3536
3537 static bool ext4_iomap_is_delalloc(struct inode *inode,
3538                                    struct ext4_map_blocks *map)
3539 {
3540         struct extent_status es;
3541         ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1;
3542
3543         ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
3544                                   map->m_lblk, end, &es);
3545
3546         if (!es.es_len || es.es_lblk > end)
3547                 return false;
3548
3549         if (es.es_lblk > map->m_lblk) {
3550                 map->m_len = es.es_lblk - map->m_lblk;
3551                 return false;
3552         }
3553
3554         offset = map->m_lblk - es.es_lblk;
3555         map->m_len = es.es_len - offset;
3556
3557         return true;
3558 }
3559
3560 static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3561                                    loff_t length, unsigned int flags,
3562                                    struct iomap *iomap, struct iomap *srcmap)
3563 {
3564         int ret;
3565         bool delalloc = false;
3566         struct ext4_map_blocks map;
3567         u8 blkbits = inode->i_blkbits;
3568
3569         if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3570                 return -EINVAL;
3571
3572         if (ext4_has_inline_data(inode)) {
3573                 ret = ext4_inline_data_iomap(inode, iomap);
3574                 if (ret != -EAGAIN) {
3575                         if (ret == 0 && offset >= iomap->length)
3576                                 ret = -ENOENT;
3577                         return ret;
3578                 }
3579         }
3580
3581         /*
3582          * Calculate the first and last logical block respectively.
3583          */
3584         map.m_lblk = offset >> blkbits;
3585         map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3586                           EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3587
3588         /*
3589          * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3590          * So handle it here itself instead of querying ext4_map_blocks().
3591          * Since ext4_map_blocks() will warn about it and will return
3592          * -EIO error.
3593          */
3594         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3595                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3596
3597                 if (offset >= sbi->s_bitmap_maxbytes) {
3598                         map.m_flags = 0;
3599                         goto set_iomap;
3600                 }
3601         }
3602
3603         ret = ext4_map_blocks(NULL, inode, &map, 0);
3604         if (ret < 0)
3605                 return ret;
3606         if (ret == 0)
3607                 delalloc = ext4_iomap_is_delalloc(inode, &map);
3608
3609 set_iomap:
3610         ext4_set_iomap(inode, iomap, &map, offset, length);
3611         if (delalloc && iomap->type == IOMAP_HOLE)
3612                 iomap->type = IOMAP_DELALLOC;
3613
3614         return 0;
3615 }
3616
3617 const struct iomap_ops ext4_iomap_report_ops = {
3618         .iomap_begin = ext4_iomap_begin_report,
3619 };
3620
3621 /*
3622  * Pages can be marked dirty completely asynchronously from ext4's journalling
3623  * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3624  * much here because ->set_page_dirty is called under VFS locks.  The page is
3625  * not necessarily locked.
3626  *
3627  * We cannot just dirty the page and leave attached buffers clean, because the
3628  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3629  * or jbddirty because all the journalling code will explode.
3630  *
3631  * So what we do is to mark the page "pending dirty" and next time writepage
3632  * is called, propagate that into the buffers appropriately.
3633  */
3634 static int ext4_journalled_set_page_dirty(struct page *page)
3635 {
3636         SetPageChecked(page);
3637         return __set_page_dirty_nobuffers(page);
3638 }
3639
3640 static int ext4_set_page_dirty(struct page *page)
3641 {
3642         WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page));
3643         WARN_ON_ONCE(!page_has_buffers(page));
3644         return __set_page_dirty_buffers(page);
3645 }
3646
3647 static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
3648                                     struct file *file, sector_t *span)
3649 {
3650         return iomap_swapfile_activate(sis, file, span,
3651                                        &ext4_iomap_report_ops);
3652 }
3653
3654 static const struct address_space_operations ext4_aops = {
3655         .readpage               = ext4_readpage,
3656         .readahead              = ext4_readahead,
3657         .writepage              = ext4_writepage,
3658         .writepages             = ext4_writepages,
3659         .write_begin            = ext4_write_begin,
3660         .write_end              = ext4_write_end,
3661         .set_page_dirty         = ext4_set_page_dirty,
3662         .bmap                   = ext4_bmap,
3663         .invalidatepage         = ext4_invalidatepage,
3664         .releasepage            = ext4_releasepage,
3665         .direct_IO              = noop_direct_IO,
3666         .migratepage            = buffer_migrate_page,
3667         .is_partially_uptodate  = block_is_partially_uptodate,
3668         .error_remove_page      = generic_error_remove_page,
3669         .swap_activate          = ext4_iomap_swap_activate,
3670 };
3671
3672 static const struct address_space_operations ext4_journalled_aops = {
3673         .readpage               = ext4_readpage,
3674         .readahead              = ext4_readahead,
3675         .writepage              = ext4_writepage,
3676         .writepages             = ext4_writepages,
3677         .write_begin            = ext4_write_begin,
3678         .write_end              = ext4_journalled_write_end,
3679         .set_page_dirty         = ext4_journalled_set_page_dirty,
3680         .bmap                   = ext4_bmap,
3681         .invalidatepage         = ext4_journalled_invalidatepage,
3682         .releasepage            = ext4_releasepage,
3683         .direct_IO              = noop_direct_IO,
3684         .is_partially_uptodate  = block_is_partially_uptodate,
3685         .error_remove_page      = generic_error_remove_page,
3686         .swap_activate          = ext4_iomap_swap_activate,
3687 };
3688
3689 static const struct address_space_operations ext4_da_aops = {
3690         .readpage               = ext4_readpage,
3691         .readahead              = ext4_readahead,
3692         .writepage              = ext4_writepage,
3693         .writepages             = ext4_writepages,
3694         .write_begin            = ext4_da_write_begin,
3695         .write_end              = ext4_da_write_end,
3696         .set_page_dirty         = ext4_set_page_dirty,
3697         .bmap                   = ext4_bmap,
3698         .invalidatepage         = ext4_invalidatepage,
3699         .releasepage            = ext4_releasepage,
3700         .direct_IO              = noop_direct_IO,
3701         .migratepage            = buffer_migrate_page,
3702         .is_partially_uptodate  = block_is_partially_uptodate,
3703         .error_remove_page      = generic_error_remove_page,
3704         .swap_activate          = ext4_iomap_swap_activate,
3705 };
3706
3707 static const struct address_space_operations ext4_dax_aops = {
3708         .writepages             = ext4_dax_writepages,
3709         .direct_IO              = noop_direct_IO,
3710         .set_page_dirty         = __set_page_dirty_no_writeback,
3711         .bmap                   = ext4_bmap,
3712         .invalidatepage         = noop_invalidatepage,
3713         .swap_activate          = ext4_iomap_swap_activate,
3714 };
3715
3716 void ext4_set_aops(struct inode *inode)
3717 {
3718         switch (ext4_inode_journal_mode(inode)) {
3719         case EXT4_INODE_ORDERED_DATA_MODE:
3720         case EXT4_INODE_WRITEBACK_DATA_MODE:
3721                 break;
3722         case EXT4_INODE_JOURNAL_DATA_MODE:
3723                 inode->i_mapping->a_ops = &ext4_journalled_aops;
3724                 return;
3725         default:
3726                 BUG();
3727         }
3728         if (IS_DAX(inode))
3729                 inode->i_mapping->a_ops = &ext4_dax_aops;
3730         else if (test_opt(inode->i_sb, DELALLOC))
3731                 inode->i_mapping->a_ops = &ext4_da_aops;
3732         else
3733                 inode->i_mapping->a_ops = &ext4_aops;
3734 }
3735
3736 static int __ext4_block_zero_page_range(handle_t *handle,
3737                 struct address_space *mapping, loff_t from, loff_t length)
3738 {
3739         ext4_fsblk_t index = from >> PAGE_SHIFT;
3740         unsigned offset = from & (PAGE_SIZE-1);
3741         unsigned blocksize, pos;
3742         ext4_lblk_t iblock;
3743         struct inode *inode = mapping->host;
3744         struct buffer_head *bh;
3745         struct page *page;
3746         int err = 0;
3747
3748         page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3749                                    mapping_gfp_constraint(mapping, ~__GFP_FS));
3750         if (!page)
3751                 return -ENOMEM;
3752
3753         blocksize = inode->i_sb->s_blocksize;
3754
3755         iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3756
3757         if (!page_has_buffers(page))
3758                 create_empty_buffers(page, blocksize, 0);
3759
3760         /* Find the buffer that contains "offset" */
3761         bh = page_buffers(page);
3762         pos = blocksize;
3763         while (offset >= pos) {
3764                 bh = bh->b_this_page;
3765                 iblock++;
3766                 pos += blocksize;
3767         }
3768         if (buffer_freed(bh)) {
3769                 BUFFER_TRACE(bh, "freed: skip");
3770                 goto unlock;
3771         }
3772         if (!buffer_mapped(bh)) {
3773                 BUFFER_TRACE(bh, "unmapped");
3774                 ext4_get_block(inode, iblock, bh, 0);
3775                 /* unmapped? It's a hole - nothing to do */
3776                 if (!buffer_mapped(bh)) {
3777                         BUFFER_TRACE(bh, "still unmapped");
3778                         goto unlock;
3779                 }
3780         }
3781
3782         /* Ok, it's mapped. Make sure it's up-to-date */
3783         if (PageUptodate(page))
3784                 set_buffer_uptodate(bh);
3785
3786         if (!buffer_uptodate(bh)) {
3787                 err = ext4_read_bh_lock(bh, 0, true);
3788                 if (err)
3789                         goto unlock;
3790                 if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
3791                         /* We expect the key to be set. */
3792                         BUG_ON(!fscrypt_has_encryption_key(inode));
3793                         err = fscrypt_decrypt_pagecache_blocks(page, blocksize,
3794                                                                bh_offset(bh));
3795                         if (err) {
3796                                 clear_buffer_uptodate(bh);
3797                                 goto unlock;
3798                         }
3799                 }
3800         }
3801         if (ext4_should_journal_data(inode)) {
3802                 BUFFER_TRACE(bh, "get write access");
3803                 err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
3804                                                     EXT4_JTR_NONE);
3805                 if (err)
3806                         goto unlock;
3807         }
3808         zero_user(page, offset, length);
3809         BUFFER_TRACE(bh, "zeroed end of block");
3810
3811         if (ext4_should_journal_data(inode)) {
3812                 err = ext4_handle_dirty_metadata(handle, inode, bh);
3813         } else {
3814                 err = 0;
3815                 mark_buffer_dirty(bh);
3816                 if (ext4_should_order_data(inode))
3817                         err = ext4_jbd2_inode_add_write(handle, inode, from,
3818                                         length);
3819         }
3820
3821 unlock:
3822         unlock_page(page);
3823         put_page(page);
3824         return err;
3825 }
3826
3827 /*
3828  * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3829  * starting from file offset 'from'.  The range to be zero'd must
3830  * be contained with in one block.  If the specified range exceeds
3831  * the end of the block it will be shortened to end of the block
3832  * that corresponds to 'from'
3833  */
3834 static int ext4_block_zero_page_range(handle_t *handle,
3835                 struct address_space *mapping, loff_t from, loff_t length)
3836 {
3837         struct inode *inode = mapping->host;
3838         unsigned offset = from & (PAGE_SIZE-1);
3839         unsigned blocksize = inode->i_sb->s_blocksize;
3840         unsigned max = blocksize - (offset & (blocksize - 1));
3841
3842         /*
3843          * correct length if it does not fall between
3844          * 'from' and the end of the block
3845          */
3846         if (length > max || length < 0)
3847                 length = max;
3848
3849         if (IS_DAX(inode)) {
3850                 return iomap_zero_range(inode, from, length, NULL,
3851                                         &ext4_iomap_ops);
3852         }
3853         return __ext4_block_zero_page_range(handle, mapping, from, length);
3854 }
3855
3856 /*
3857  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3858  * up to the end of the block which corresponds to `from'.
3859  * This required during truncate. We need to physically zero the tail end
3860  * of that block so it doesn't yield old data if the file is later grown.
3861  */
3862 static int ext4_block_truncate_page(handle_t *handle,
3863                 struct address_space *mapping, loff_t from)
3864 {
3865         unsigned offset = from & (PAGE_SIZE-1);
3866         unsigned length;
3867         unsigned blocksize;
3868         struct inode *inode = mapping->host;
3869
3870         /* If we are processing an encrypted inode during orphan list handling */
3871         if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
3872                 return 0;
3873
3874         blocksize = inode->i_sb->s_blocksize;
3875         length = blocksize - (offset & (blocksize - 1));
3876
3877         return ext4_block_zero_page_range(handle, mapping, from, length);
3878 }
3879
3880 int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3881                              loff_t lstart, loff_t length)
3882 {
3883         struct super_block *sb = inode->i_sb;
3884         struct address_space *mapping = inode->i_mapping;
3885         unsigned partial_start, partial_end;
3886         ext4_fsblk_t start, end;
3887         loff_t byte_end = (lstart + length - 1);
3888         int err = 0;
3889
3890         partial_start = lstart & (sb->s_blocksize - 1);
3891         partial_end = byte_end & (sb->s_blocksize - 1);
3892
3893         start = lstart >> sb->s_blocksize_bits;
3894         end = byte_end >> sb->s_blocksize_bits;
3895
3896         /* Handle partial zero within the single block */
3897         if (start == end &&
3898             (partial_start || (partial_end != sb->s_blocksize - 1))) {
3899                 err = ext4_block_zero_page_range(handle, mapping,
3900                                                  lstart, length);
3901                 return err;
3902         }
3903         /* Handle partial zero out on the start of the range */
3904         if (partial_start) {
3905                 err = ext4_block_zero_page_range(handle, mapping,
3906                                                  lstart, sb->s_blocksize);
3907                 if (err)
3908                         return err;
3909         }
3910         /* Handle partial zero out on the end of the range */
3911         if (partial_end != sb->s_blocksize - 1)
3912                 err = ext4_block_zero_page_range(handle, mapping,
3913                                                  byte_end - partial_end,
3914                                                  partial_end + 1);
3915         return err;
3916 }
3917
3918 int ext4_can_truncate(struct inode *inode)
3919 {
3920         if (S_ISREG(inode->i_mode))
3921                 return 1;
3922         if (S_ISDIR(inode->i_mode))
3923                 return 1;
3924         if (S_ISLNK(inode->i_mode))
3925                 return !ext4_inode_is_fast_symlink(inode);
3926         return 0;
3927 }
3928
3929 /*
3930  * We have to make sure i_disksize gets properly updated before we truncate
3931  * page cache due to hole punching or zero range. Otherwise i_disksize update
3932  * can get lost as it may have been postponed to submission of writeback but
3933  * that will never happen after we truncate page cache.
3934  */
3935 int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3936                                       loff_t len)
3937 {
3938         handle_t *handle;
3939         int ret;
3940
3941         loff_t size = i_size_read(inode);
3942
3943         WARN_ON(!inode_is_locked(inode));
3944         if (offset > size || offset + len < size)
3945                 return 0;
3946
3947         if (EXT4_I(inode)->i_disksize >= size)
3948                 return 0;
3949
3950         handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3951         if (IS_ERR(handle))
3952                 return PTR_ERR(handle);
3953         ext4_update_i_disksize(inode, size);
3954         ret = ext4_mark_inode_dirty(handle, inode);
3955         ext4_journal_stop(handle);
3956
3957         return ret;
3958 }
3959
3960 static void ext4_wait_dax_page(struct inode *inode)
3961 {
3962         filemap_invalidate_unlock(inode->i_mapping);
3963         schedule();
3964         filemap_invalidate_lock(inode->i_mapping);
3965 }
3966
3967 int ext4_break_layouts(struct inode *inode)
3968 {
3969         struct page *page;
3970         int error;
3971
3972         if (WARN_ON_ONCE(!rwsem_is_locked(&inode->i_mapping->invalidate_lock)))
3973                 return -EINVAL;
3974
3975         do {
3976                 page = dax_layout_busy_page(inode->i_mapping);
3977                 if (!page)
3978                         return 0;
3979
3980                 error = ___wait_var_event(&page->_refcount,
3981                                 atomic_read(&page->_refcount) == 1,
3982                                 TASK_INTERRUPTIBLE, 0, 0,
3983                                 ext4_wait_dax_page(inode));
3984         } while (error == 0);
3985
3986         return error;
3987 }
3988
3989 /*
3990  * ext4_punch_hole: punches a hole in a file by releasing the blocks
3991  * associated with the given offset and length
3992  *
3993  * @inode:  File inode
3994  * @offset: The offset where the hole will begin
3995  * @len:    The length of the hole
3996  *
3997  * Returns: 0 on success or negative on failure
3998  */
3999
4000 int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
4001 {
4002         struct super_block *sb = inode->i_sb;
4003         ext4_lblk_t first_block, stop_block;
4004         struct address_space *mapping = inode->i_mapping;
4005         loff_t first_block_offset, last_block_offset;
4006         handle_t *handle;
4007         unsigned int credits;
4008         int ret = 0, ret2 = 0;
4009
4010         trace_ext4_punch_hole(inode, offset, length, 0);
4011
4012         ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
4013         if (ext4_has_inline_data(inode)) {
4014                 filemap_invalidate_lock(mapping);
4015                 ret = ext4_convert_inline_data(inode);
4016                 filemap_invalidate_unlock(mapping);
4017                 if (ret)
4018                         return ret;
4019         }
4020
4021         /*
4022          * Write out all dirty pages to avoid race conditions
4023          * Then release them.
4024          */
4025         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4026                 ret = filemap_write_and_wait_range(mapping, offset,
4027                                                    offset + length - 1);
4028                 if (ret)
4029                         return ret;
4030         }
4031
4032         inode_lock(inode);
4033
4034         /* No need to punch hole beyond i_size */
4035         if (offset >= inode->i_size)
4036                 goto out_mutex;
4037
4038         /*
4039          * If the hole extends beyond i_size, set the hole
4040          * to end after the page that contains i_size
4041          */
4042         if (offset + length > inode->i_size) {
4043                 length = inode->i_size +
4044                    PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
4045                    offset;
4046         }
4047
4048         if (offset & (sb->s_blocksize - 1) ||
4049             (offset + length) & (sb->s_blocksize - 1)) {
4050                 /*
4051                  * Attach jinode to inode for jbd2 if we do any zeroing of
4052                  * partial block
4053                  */
4054                 ret = ext4_inode_attach_jinode(inode);
4055                 if (ret < 0)
4056                         goto out_mutex;
4057
4058         }
4059
4060         /* Wait all existing dio workers, newcomers will block on i_mutex */
4061         inode_dio_wait(inode);
4062
4063         /*
4064          * Prevent page faults from reinstantiating pages we have released from
4065          * page cache.
4066          */
4067         filemap_invalidate_lock(mapping);
4068
4069         ret = ext4_break_layouts(inode);
4070         if (ret)
4071                 goto out_dio;
4072
4073         first_block_offset = round_up(offset, sb->s_blocksize);
4074         last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
4075
4076         /* Now release the pages and zero block aligned part of pages*/
4077         if (last_block_offset > first_block_offset) {
4078                 ret = ext4_update_disksize_before_punch(inode, offset, length);
4079                 if (ret)
4080                         goto out_dio;
4081                 truncate_pagecache_range(inode, first_block_offset,
4082                                          last_block_offset);
4083         }
4084
4085         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4086                 credits = ext4_writepage_trans_blocks(inode);
4087         else
4088                 credits = ext4_blocks_for_truncate(inode);
4089         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4090         if (IS_ERR(handle)) {
4091                 ret = PTR_ERR(handle);
4092                 ext4_std_error(sb, ret);
4093                 goto out_dio;
4094         }
4095
4096         ret = ext4_zero_partial_blocks(handle, inode, offset,
4097                                        length);
4098         if (ret)
4099                 goto out_stop;
4100
4101         first_block = (offset + sb->s_blocksize - 1) >>
4102                 EXT4_BLOCK_SIZE_BITS(sb);
4103         stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4104
4105         /* If there are blocks to remove, do it */
4106         if (stop_block > first_block) {
4107
4108                 down_write(&EXT4_I(inode)->i_data_sem);
4109                 ext4_discard_preallocations(inode, 0);
4110
4111                 ret = ext4_es_remove_extent(inode, first_block,
4112                                             stop_block - first_block);
4113                 if (ret) {
4114                         up_write(&EXT4_I(inode)->i_data_sem);
4115                         goto out_stop;
4116                 }
4117
4118                 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4119                         ret = ext4_ext_remove_space(inode, first_block,
4120                                                     stop_block - 1);
4121                 else
4122                         ret = ext4_ind_remove_space(handle, inode, first_block,
4123                                                     stop_block);
4124
4125                 up_write(&EXT4_I(inode)->i_data_sem);
4126         }
4127         ext4_fc_track_range(handle, inode, first_block, stop_block);
4128         if (IS_SYNC(inode))
4129                 ext4_handle_sync(handle);
4130
4131         inode->i_mtime = inode->i_ctime = current_time(inode);
4132         ret2 = ext4_mark_inode_dirty(handle, inode);
4133         if (unlikely(ret2))
4134                 ret = ret2;
4135         if (ret >= 0)
4136                 ext4_update_inode_fsync_trans(handle, inode, 1);
4137 out_stop:
4138         ext4_journal_stop(handle);
4139 out_dio:
4140         filemap_invalidate_unlock(mapping);
4141 out_mutex:
4142         inode_unlock(inode);
4143         return ret;
4144 }
4145
4146 int ext4_inode_attach_jinode(struct inode *inode)
4147 {
4148         struct ext4_inode_info *ei = EXT4_I(inode);
4149         struct jbd2_inode *jinode;
4150
4151         if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4152                 return 0;
4153
4154         jinode = jbd2_alloc_inode(GFP_KERNEL);
4155         spin_lock(&inode->i_lock);
4156         if (!ei->jinode) {
4157                 if (!jinode) {
4158                         spin_unlock(&inode->i_lock);
4159                         return -ENOMEM;
4160                 }
4161                 ei->jinode = jinode;
4162                 jbd2_journal_init_jbd_inode(ei->jinode, inode);
4163                 jinode = NULL;
4164         }
4165         spin_unlock(&inode->i_lock);
4166         if (unlikely(jinode != NULL))
4167                 jbd2_free_inode(jinode);
4168         return 0;
4169 }
4170
4171 /*
4172  * ext4_truncate()
4173  *
4174  * We block out ext4_get_block() block instantiations across the entire
4175  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4176  * simultaneously on behalf of the same inode.
4177  *
4178  * As we work through the truncate and commit bits of it to the journal there
4179  * is one core, guiding principle: the file's tree must always be consistent on
4180  * disk.  We must be able to restart the truncate after a crash.
4181  *
4182  * The file's tree may be transiently inconsistent in memory (although it
4183  * probably isn't), but whenever we close off and commit a journal transaction,
4184  * the contents of (the filesystem + the journal) must be consistent and
4185  * restartable.  It's pretty simple, really: bottom up, right to left (although
4186  * left-to-right works OK too).
4187  *
4188  * Note that at recovery time, journal replay occurs *before* the restart of
4189  * truncate against the orphan inode list.
4190  *
4191  * The committed inode has the new, desired i_size (which is the same as
4192  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4193  * that this inode's truncate did not complete and it will again call
4194  * ext4_truncate() to have another go.  So there will be instantiated blocks
4195  * to the right of the truncation point in a crashed ext4 filesystem.  But
4196  * that's fine - as long as they are linked from the inode, the post-crash
4197  * ext4_truncate() run will find them and release them.
4198  */
4199 int ext4_truncate(struct inode *inode)
4200 {
4201         struct ext4_inode_info *ei = EXT4_I(inode);
4202         unsigned int credits;
4203         int err = 0, err2;
4204         handle_t *handle;
4205         struct address_space *mapping = inode->i_mapping;
4206
4207         /*
4208          * There is a possibility that we're either freeing the inode
4209          * or it's a completely new inode. In those cases we might not
4210          * have i_mutex locked because it's not necessary.
4211          */
4212         if (!(inode->i_state & (I_NEW|I_FREEING)))
4213                 WARN_ON(!inode_is_locked(inode));
4214         trace_ext4_truncate_enter(inode);
4215
4216         if (!ext4_can_truncate(inode))
4217                 goto out_trace;
4218
4219         if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4220                 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4221
4222         if (ext4_has_inline_data(inode)) {
4223                 int has_inline = 1;
4224
4225                 err = ext4_inline_data_truncate(inode, &has_inline);
4226                 if (err || has_inline)
4227                         goto out_trace;
4228         }
4229
4230         /* If we zero-out tail of the page, we have to create jinode for jbd2 */
4231         if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4232                 if (ext4_inode_attach_jinode(inode) < 0)
4233                         goto out_trace;
4234         }
4235
4236         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4237                 credits = ext4_writepage_trans_blocks(inode);
4238         else
4239                 credits = ext4_blocks_for_truncate(inode);
4240
4241         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4242         if (IS_ERR(handle)) {
4243                 err = PTR_ERR(handle);
4244                 goto out_trace;
4245         }
4246
4247         if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4248                 ext4_block_truncate_page(handle, mapping, inode->i_size);
4249
4250         /*
4251          * We add the inode to the orphan list, so that if this
4252          * truncate spans multiple transactions, and we crash, we will
4253          * resume the truncate when the filesystem recovers.  It also
4254          * marks the inode dirty, to catch the new size.
4255          *
4256          * Implication: the file must always be in a sane, consistent
4257          * truncatable state while each transaction commits.
4258          */
4259         err = ext4_orphan_add(handle, inode);
4260         if (err)
4261                 goto out_stop;
4262
4263         down_write(&EXT4_I(inode)->i_data_sem);
4264
4265         ext4_discard_preallocations(inode, 0);
4266
4267         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4268                 err = ext4_ext_truncate(handle, inode);
4269         else
4270                 ext4_ind_truncate(handle, inode);
4271
4272         up_write(&ei->i_data_sem);
4273         if (err)
4274                 goto out_stop;
4275
4276         if (IS_SYNC(inode))
4277                 ext4_handle_sync(handle);
4278
4279 out_stop:
4280         /*
4281          * If this was a simple ftruncate() and the file will remain alive,
4282          * then we need to clear up the orphan record which we created above.
4283          * However, if this was a real unlink then we were called by
4284          * ext4_evict_inode(), and we allow that function to clean up the
4285          * orphan info for us.
4286          */
4287         if (inode->i_nlink)
4288                 ext4_orphan_del(handle, inode);
4289
4290         inode->i_mtime = inode->i_ctime = current_time(inode);
4291         err2 = ext4_mark_inode_dirty(handle, inode);
4292         if (unlikely(err2 && !err))
4293                 err = err2;
4294         ext4_journal_stop(handle);
4295
4296 out_trace:
4297         trace_ext4_truncate_exit(inode);
4298         return err;
4299 }
4300
4301 /*
4302  * ext4_get_inode_loc returns with an extra refcount against the inode's
4303  * underlying buffer_head on success. If 'in_mem' is true, we have all
4304  * data in memory that is needed to recreate the on-disk version of this
4305  * inode.
4306  */
4307 static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
4308                                 struct ext4_iloc *iloc, int in_mem,
4309                                 ext4_fsblk_t *ret_block)
4310 {
4311         struct ext4_group_desc  *gdp;
4312         struct buffer_head      *bh;
4313         ext4_fsblk_t            block;
4314         struct blk_plug         plug;
4315         int                     inodes_per_block, inode_offset;
4316
4317         iloc->bh = NULL;
4318         if (ino < EXT4_ROOT_INO ||
4319             ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4320                 return -EFSCORRUPTED;
4321
4322         iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
4323         gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4324         if (!gdp)
4325                 return -EIO;
4326
4327         /*
4328          * Figure out the offset within the block group inode table
4329          */
4330         inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4331         inode_offset = ((ino - 1) %
4332                         EXT4_INODES_PER_GROUP(sb));
4333         block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4334         iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4335
4336         bh = sb_getblk(sb, block);
4337         if (unlikely(!bh))
4338                 return -ENOMEM;
4339         if (ext4_buffer_uptodate(bh))
4340                 goto has_buffer;
4341
4342         lock_buffer(bh);
4343         /*
4344          * If we have all information of the inode in memory and this
4345          * is the only valid inode in the block, we need not read the
4346          * block.
4347          */
4348         if (in_mem) {
4349                 struct buffer_head *bitmap_bh;
4350                 int i, start;
4351
4352                 start = inode_offset & ~(inodes_per_block - 1);
4353
4354                 /* Is the inode bitmap in cache? */
4355                 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4356                 if (unlikely(!bitmap_bh))
4357                         goto make_io;
4358
4359                 /*
4360                  * If the inode bitmap isn't in cache then the
4361                  * optimisation may end up performing two reads instead
4362                  * of one, so skip it.
4363                  */
4364                 if (!buffer_uptodate(bitmap_bh)) {
4365                         brelse(bitmap_bh);
4366                         goto make_io;
4367                 }
4368                 for (i = start; i < start + inodes_per_block; i++) {
4369                         if (i == inode_offset)
4370                                 continue;
4371                         if (ext4_test_bit(i, bitmap_bh->b_data))
4372                                 break;
4373                 }
4374                 brelse(bitmap_bh);
4375                 if (i == start + inodes_per_block) {
4376                         /* all other inodes are free, so skip I/O */
4377                         memset(bh->b_data, 0, bh->b_size);
4378                         set_buffer_uptodate(bh);
4379                         unlock_buffer(bh);
4380                         goto has_buffer;
4381                 }
4382         }
4383
4384 make_io:
4385         /*
4386          * If we need to do any I/O, try to pre-readahead extra
4387          * blocks from the inode table.
4388          */
4389         blk_start_plug(&plug);
4390         if (EXT4_SB(sb)->s_inode_readahead_blks) {
4391                 ext4_fsblk_t b, end, table;
4392                 unsigned num;
4393                 __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4394
4395                 table = ext4_inode_table(sb, gdp);
4396                 /* s_inode_readahead_blks is always a power of 2 */
4397                 b = block & ~((ext4_fsblk_t) ra_blks - 1);
4398                 if (table > b)
4399                         b = table;
4400                 end = b + ra_blks;
4401                 num = EXT4_INODES_PER_GROUP(sb);
4402                 if (ext4_has_group_desc_csum(sb))
4403                         num -= ext4_itable_unused_count(sb, gdp);
4404                 table += num / inodes_per_block;
4405                 if (end > table)
4406                         end = table;
4407                 while (b <= end)
4408                         ext4_sb_breadahead_unmovable(sb, b++);
4409         }
4410
4411         /*
4412          * There are other valid inodes in the buffer, this inode
4413          * has in-inode xattrs, or we don't have this inode in memory.
4414          * Read the block from disk.
4415          */
4416         trace_ext4_load_inode(sb, ino);
4417         ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
4418         blk_finish_plug(&plug);
4419         wait_on_buffer(bh);
4420         ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
4421         if (!buffer_uptodate(bh)) {
4422                 if (ret_block)
4423                         *ret_block = block;
4424                 brelse(bh);
4425                 return -EIO;
4426         }
4427 has_buffer:
4428         iloc->bh = bh;
4429         return 0;
4430 }
4431
4432 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
4433                                         struct ext4_iloc *iloc)
4434 {
4435         ext4_fsblk_t err_blk;
4436         int ret;
4437
4438         ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, 0,
4439                                         &err_blk);
4440
4441         if (ret == -EIO)
4442                 ext4_error_inode_block(inode, err_blk, EIO,
4443                                         "unable to read itable block");
4444
4445         return ret;
4446 }
4447
4448 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4449 {
4450         ext4_fsblk_t err_blk;
4451         int ret;
4452
4453         /* We have all inode data except xattrs in memory here. */
4454         ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc,
4455                 !ext4_test_inode_state(inode, EXT4_STATE_XATTR), &err_blk);
4456
4457         if (ret == -EIO)
4458                 ext4_error_inode_block(inode, err_blk, EIO,
4459                                         "unable to read itable block");
4460
4461         return ret;
4462 }
4463
4464
4465 int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
4466                           struct ext4_iloc *iloc)
4467 {
4468         return __ext4_get_inode_loc(sb, ino, iloc, 0, NULL);
4469 }
4470
4471 static bool ext4_should_enable_dax(struct inode *inode)
4472 {
4473         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4474
4475         if (test_opt2(inode->i_sb, DAX_NEVER))
4476                 return false;
4477         if (!S_ISREG(inode->i_mode))
4478                 return false;
4479         if (ext4_should_journal_data(inode))
4480                 return false;
4481         if (ext4_has_inline_data(inode))
4482                 return false;
4483         if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
4484                 return false;
4485         if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
4486                 return false;
4487         if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4488                 return false;
4489         if (test_opt(inode->i_sb, DAX_ALWAYS))
4490                 return true;
4491
4492         return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
4493 }
4494
4495 void ext4_set_inode_flags(struct inode *inode, bool init)
4496 {
4497         unsigned int flags = EXT4_I(inode)->i_flags;
4498         unsigned int new_fl = 0;
4499
4500         WARN_ON_ONCE(IS_DAX(inode) && init);
4501
4502         if (flags & EXT4_SYNC_FL)
4503                 new_fl |= S_SYNC;
4504         if (flags & EXT4_APPEND_FL)
4505                 new_fl |= S_APPEND;
4506         if (flags & EXT4_IMMUTABLE_FL)
4507                 new_fl |= S_IMMUTABLE;
4508         if (flags & EXT4_NOATIME_FL)
4509                 new_fl |= S_NOATIME;
4510         if (flags & EXT4_DIRSYNC_FL)
4511                 new_fl |= S_DIRSYNC;
4512
4513         /* Because of the way inode_set_flags() works we must preserve S_DAX
4514          * here if already set. */
4515         new_fl |= (inode->i_flags & S_DAX);
4516         if (init && ext4_should_enable_dax(inode))
4517                 new_fl |= S_DAX;
4518
4519         if (flags & EXT4_ENCRYPT_FL)
4520                 new_fl |= S_ENCRYPTED;
4521         if (flags & EXT4_CASEFOLD_FL)
4522                 new_fl |= S_CASEFOLD;
4523         if (flags & EXT4_VERITY_FL)
4524                 new_fl |= S_VERITY;
4525         inode_set_flags(inode, new_fl,
4526                         S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4527                         S_ENCRYPTED|S_CASEFOLD|S_VERITY);
4528 }
4529
4530 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4531                                   struct ext4_inode_info *ei)
4532 {
4533         blkcnt_t i_blocks ;
4534         struct inode *inode = &(ei->vfs_inode);
4535         struct super_block *sb = inode->i_sb;
4536
4537         if (ext4_has_feature_huge_file(sb)) {
4538                 /* we are using combined 48 bit field */
4539                 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4540                                         le32_to_cpu(raw_inode->i_blocks_lo);
4541                 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4542                         /* i_blocks represent file system block size */
4543                         return i_blocks  << (inode->i_blkbits - 9);
4544                 } else {
4545                         return i_blocks;
4546                 }
4547         } else {
4548                 return le32_to_cpu(raw_inode->i_blocks_lo);
4549         }
4550 }
4551
4552 static inline int ext4_iget_extra_inode(struct inode *inode,
4553                                          struct ext4_inode *raw_inode,
4554                                          struct ext4_inode_info *ei)
4555 {
4556         __le32 *magic = (void *)raw_inode +
4557                         EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4558
4559         if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize + sizeof(__le32) <=
4560             EXT4_INODE_SIZE(inode->i_sb) &&
4561             *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4562                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4563                 return ext4_find_inline_data_nolock(inode);
4564         } else
4565                 EXT4_I(inode)->i_inline_off = 0;
4566         return 0;
4567 }
4568
4569 int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4570 {
4571         if (!ext4_has_feature_project(inode->i_sb))
4572                 return -EOPNOTSUPP;
4573         *projid = EXT4_I(inode)->i_projid;
4574         return 0;
4575 }
4576
4577 /*
4578  * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
4579  * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
4580  * set.
4581  */
4582 static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
4583 {
4584         if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4585                 inode_set_iversion_raw(inode, val);
4586         else
4587                 inode_set_iversion_queried(inode, val);
4588 }
4589 static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4590 {
4591         if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4592                 return inode_peek_iversion_raw(inode);
4593         else
4594                 return inode_peek_iversion(inode);
4595 }
4596
4597 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
4598                           ext4_iget_flags flags, const char *function,
4599                           unsigned int line)
4600 {
4601         struct ext4_iloc iloc;
4602         struct ext4_inode *raw_inode;
4603         struct ext4_inode_info *ei;
4604         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4605         struct inode *inode;
4606         journal_t *journal = EXT4_SB(sb)->s_journal;
4607         long ret;
4608         loff_t size;
4609         int block;
4610         uid_t i_uid;
4611         gid_t i_gid;
4612         projid_t i_projid;
4613
4614         if ((!(flags & EXT4_IGET_SPECIAL) &&
4615              ((ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO) ||
4616               ino == le32_to_cpu(es->s_usr_quota_inum) ||
4617               ino == le32_to_cpu(es->s_grp_quota_inum) ||
4618               ino == le32_to_cpu(es->s_prj_quota_inum) ||
4619               ino == le32_to_cpu(es->s_orphan_file_inum))) ||
4620             (ino < EXT4_ROOT_INO) ||
4621             (ino > le32_to_cpu(es->s_inodes_count))) {
4622                 if (flags & EXT4_IGET_HANDLE)
4623                         return ERR_PTR(-ESTALE);
4624                 __ext4_error(sb, function, line, false, EFSCORRUPTED, 0,
4625                              "inode #%lu: comm %s: iget: illegal inode #",
4626                              ino, current->comm);
4627                 return ERR_PTR(-EFSCORRUPTED);
4628         }
4629
4630         inode = iget_locked(sb, ino);
4631         if (!inode)
4632                 return ERR_PTR(-ENOMEM);
4633         if (!(inode->i_state & I_NEW))
4634                 return inode;
4635
4636         ei = EXT4_I(inode);
4637         iloc.bh = NULL;
4638
4639         ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
4640         if (ret < 0)
4641                 goto bad_inode;
4642         raw_inode = ext4_raw_inode(&iloc);
4643
4644         if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) {
4645                 ext4_error_inode(inode, function, line, 0,
4646                                  "iget: root inode unallocated");
4647                 ret = -EFSCORRUPTED;
4648                 goto bad_inode;
4649         }
4650
4651         if ((flags & EXT4_IGET_HANDLE) &&
4652             (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
4653                 ret = -ESTALE;
4654                 goto bad_inode;
4655         }
4656
4657         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4658                 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4659                 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4660                         EXT4_INODE_SIZE(inode->i_sb) ||
4661                     (ei->i_extra_isize & 3)) {
4662                         ext4_error_inode(inode, function, line, 0,
4663                                          "iget: bad extra_isize %u "
4664                                          "(inode size %u)",
4665                                          ei->i_extra_isize,
4666                                          EXT4_INODE_SIZE(inode->i_sb));
4667                         ret = -EFSCORRUPTED;
4668                         goto bad_inode;
4669                 }
4670         } else
4671                 ei->i_extra_isize = 0;
4672
4673         /* Precompute checksum seed for inode metadata */
4674         if (ext4_has_metadata_csum(sb)) {
4675                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4676                 __u32 csum;
4677                 __le32 inum = cpu_to_le32(inode->i_ino);
4678                 __le32 gen = raw_inode->i_generation;
4679                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4680                                    sizeof(inum));
4681                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4682                                               sizeof(gen));
4683         }
4684
4685         if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
4686             ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
4687              (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
4688                 ext4_error_inode_err(inode, function, line, 0,
4689                                 EFSBADCRC, "iget: checksum invalid");
4690                 ret = -EFSBADCRC;
4691                 goto bad_inode;
4692         }
4693
4694         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4695         i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4696         i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4697         if (ext4_has_feature_project(sb) &&
4698             EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4699             EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4700                 i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4701         else
4702                 i_projid = EXT4_DEF_PROJID;
4703
4704         if (!(test_opt(inode->i_sb, NO_UID32))) {
4705                 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4706                 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4707         }
4708         i_uid_write(inode, i_uid);
4709         i_gid_write(inode, i_gid);
4710         ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4711         set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4712
4713         ext4_clear_state_flags(ei);     /* Only relevant on 32-bit archs */
4714         ei->i_inline_off = 0;
4715         ei->i_dir_start_lookup = 0;
4716         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4717         /* We now have enough fields to check if the inode was active or not.
4718          * This is needed because nfsd might try to access dead inodes
4719          * the test is that same one that e2fsck uses
4720          * NeilBrown 1999oct15
4721          */
4722         if (inode->i_nlink == 0) {
4723                 if ((inode->i_mode == 0 ||
4724                      !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4725                     ino != EXT4_BOOT_LOADER_INO) {
4726                         /* this inode is deleted */
4727                         ret = -ESTALE;
4728                         goto bad_inode;
4729                 }
4730                 /* The only unlinked inodes we let through here have
4731                  * valid i_mode and are being read by the orphan
4732                  * recovery code: that's fine, we're about to complete
4733                  * the process of deleting those.
4734                  * OR it is the EXT4_BOOT_LOADER_INO which is
4735                  * not initialized on a new filesystem. */
4736         }
4737         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4738         ext4_set_inode_flags(inode, true);
4739         inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4740         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4741         if (ext4_has_feature_64bit(sb))
4742                 ei->i_file_acl |=
4743                         ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4744         inode->i_size = ext4_isize(sb, raw_inode);
4745         if ((size = i_size_read(inode)) < 0) {
4746                 ext4_error_inode(inode, function, line, 0,
4747                                  "iget: bad i_size value: %lld", size);
4748                 ret = -EFSCORRUPTED;
4749                 goto bad_inode;
4750         }
4751         /*
4752          * If dir_index is not enabled but there's dir with INDEX flag set,
4753          * we'd normally treat htree data as empty space. But with metadata
4754          * checksumming that corrupts checksums so forbid that.
4755          */
4756         if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
4757             ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
4758                 ext4_error_inode(inode, function, line, 0,
4759                          "iget: Dir with htree data on filesystem without dir_index feature.");
4760                 ret = -EFSCORRUPTED;
4761                 goto bad_inode;
4762         }
4763         ei->i_disksize = inode->i_size;
4764 #ifdef CONFIG_QUOTA
4765         ei->i_reserved_quota = 0;
4766 #endif
4767         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4768         ei->i_block_group = iloc.block_group;
4769         ei->i_last_alloc_group = ~0;
4770         /*
4771          * NOTE! The in-memory inode i_data array is in little-endian order
4772          * even on big-endian machines: we do NOT byteswap the block numbers!
4773          */
4774         for (block = 0; block < EXT4_N_BLOCKS; block++)
4775                 ei->i_data[block] = raw_inode->i_block[block];
4776         INIT_LIST_HEAD(&ei->i_orphan);
4777         ext4_fc_init_inode(&ei->vfs_inode);
4778
4779         /*
4780          * Set transaction id's of transactions that have to be committed
4781          * to finish f[data]sync. We set them to currently running transaction
4782          * as we cannot be sure that the inode or some of its metadata isn't
4783          * part of the transaction - the inode could have been reclaimed and
4784          * now it is reread from disk.
4785          */
4786         if (journal) {
4787                 transaction_t *transaction;
4788                 tid_t tid;
4789
4790                 read_lock(&journal->j_state_lock);
4791                 if (journal->j_running_transaction)
4792                         transaction = journal->j_running_transaction;
4793                 else
4794                         transaction = journal->j_committing_transaction;
4795                 if (transaction)
4796                         tid = transaction->t_tid;
4797                 else
4798                         tid = journal->j_commit_sequence;
4799                 read_unlock(&journal->j_state_lock);
4800                 ei->i_sync_tid = tid;
4801                 ei->i_datasync_tid = tid;
4802         }
4803
4804         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4805                 if (ei->i_extra_isize == 0) {
4806                         /* The extra space is currently unused. Use it. */
4807                         BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4808                         ei->i_extra_isize = sizeof(struct ext4_inode) -
4809                                             EXT4_GOOD_OLD_INODE_SIZE;
4810                 } else {
4811                         ret = ext4_iget_extra_inode(inode, raw_inode, ei);
4812                         if (ret)
4813                                 goto bad_inode;
4814                 }
4815         }
4816
4817         EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4818         EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4819         EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4820         EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4821
4822         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4823                 u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4824
4825                 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4826                         if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4827                                 ivers |=
4828                     (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4829                 }
4830                 ext4_inode_set_iversion_queried(inode, ivers);
4831         }
4832
4833         ret = 0;
4834         if (ei->i_file_acl &&
4835             !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
4836                 ext4_error_inode(inode, function, line, 0,
4837                                  "iget: bad extended attribute block %llu",
4838                                  ei->i_file_acl);
4839                 ret = -EFSCORRUPTED;
4840                 goto bad_inode;
4841         } else if (!ext4_has_inline_data(inode)) {
4842                 /* validate the block references in the inode */
4843                 if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
4844                         (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4845                         (S_ISLNK(inode->i_mode) &&
4846                         !ext4_inode_is_fast_symlink(inode)))) {
4847                         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4848                                 ret = ext4_ext_check_inode(inode);
4849                         else
4850                                 ret = ext4_ind_check_inode(inode);
4851                 }
4852         }
4853         if (ret)
4854                 goto bad_inode;
4855
4856         if (S_ISREG(inode->i_mode)) {
4857                 inode->i_op = &ext4_file_inode_operations;
4858                 inode->i_fop = &ext4_file_operations;
4859                 ext4_set_aops(inode);
4860         } else if (S_ISDIR(inode->i_mode)) {
4861                 inode->i_op = &ext4_dir_inode_operations;
4862                 inode->i_fop = &ext4_dir_operations;
4863         } else if (S_ISLNK(inode->i_mode)) {
4864                 /* VFS does not allow setting these so must be corruption */
4865                 if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
4866                         ext4_error_inode(inode, function, line, 0,
4867                                          "iget: immutable or append flags "
4868                                          "not allowed on symlinks");
4869                         ret = -EFSCORRUPTED;
4870                         goto bad_inode;
4871                 }
4872                 if (IS_ENCRYPTED(inode)) {
4873                         inode->i_op = &ext4_encrypted_symlink_inode_operations;
4874                         ext4_set_aops(inode);
4875                 } else if (ext4_inode_is_fast_symlink(inode)) {
4876                         inode->i_link = (char *)ei->i_data;
4877                         inode->i_op = &ext4_fast_symlink_inode_operations;
4878                         nd_terminate_link(ei->i_data, inode->i_size,
4879                                 sizeof(ei->i_data) - 1);
4880                 } else {
4881                         inode->i_op = &ext4_symlink_inode_operations;
4882                         ext4_set_aops(inode);
4883                 }
4884                 inode_nohighmem(inode);
4885         } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4886               S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4887                 inode->i_op = &ext4_special_inode_operations;
4888                 if (raw_inode->i_block[0])
4889                         init_special_inode(inode, inode->i_mode,
4890                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4891                 else
4892                         init_special_inode(inode, inode->i_mode,
4893                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4894         } else if (ino == EXT4_BOOT_LOADER_INO) {
4895                 make_bad_inode(inode);
4896         } else {
4897                 ret = -EFSCORRUPTED;
4898                 ext4_error_inode(inode, function, line, 0,
4899                                  "iget: bogus i_mode (%o)", inode->i_mode);
4900                 goto bad_inode;
4901         }
4902         if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb))
4903                 ext4_error_inode(inode, function, line, 0,
4904                                  "casefold flag without casefold feature");
4905         brelse(iloc.bh);
4906
4907         unlock_new_inode(inode);
4908         return inode;
4909
4910 bad_inode:
4911         brelse(iloc.bh);
4912         iget_failed(inode);
4913         return ERR_PTR(ret);
4914 }
4915
4916 static int ext4_inode_blocks_set(handle_t *handle,
4917                                 struct ext4_inode *raw_inode,
4918                                 struct ext4_inode_info *ei)
4919 {
4920         struct inode *inode = &(ei->vfs_inode);
4921         u64 i_blocks = READ_ONCE(inode->i_blocks);
4922         struct super_block *sb = inode->i_sb;
4923
4924         if (i_blocks <= ~0U) {
4925                 /*
4926                  * i_blocks can be represented in a 32 bit variable
4927                  * as multiple of 512 bytes
4928                  */
4929                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4930                 raw_inode->i_blocks_high = 0;
4931                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4932                 return 0;
4933         }
4934
4935         /*
4936          * This should never happen since sb->s_maxbytes should not have
4937          * allowed this, sb->s_maxbytes was set according to the huge_file
4938          * feature in ext4_fill_super().
4939          */
4940         if (!ext4_has_feature_huge_file(sb))
4941                 return -EFSCORRUPTED;
4942
4943         if (i_blocks <= 0xffffffffffffULL) {
4944                 /*
4945                  * i_blocks can be represented in a 48 bit variable
4946                  * as multiple of 512 bytes
4947                  */
4948                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4949                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4950                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4951         } else {
4952                 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4953                 /* i_block is stored in file system block size */
4954                 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4955                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4956                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4957         }
4958         return 0;
4959 }
4960
4961 static void __ext4_update_other_inode_time(struct super_block *sb,
4962                                            unsigned long orig_ino,
4963                                            unsigned long ino,
4964                                            struct ext4_inode *raw_inode)
4965 {
4966         struct inode *inode;
4967
4968         inode = find_inode_by_ino_rcu(sb, ino);
4969         if (!inode)
4970                 return;
4971
4972         if (!inode_is_dirtytime_only(inode))
4973                 return;
4974
4975         spin_lock(&inode->i_lock);
4976         if (inode_is_dirtytime_only(inode)) {
4977                 struct ext4_inode_info  *ei = EXT4_I(inode);
4978
4979                 inode->i_state &= ~I_DIRTY_TIME;
4980                 spin_unlock(&inode->i_lock);
4981
4982                 spin_lock(&ei->i_raw_lock);
4983                 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4984                 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4985                 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4986                 ext4_inode_csum_set(inode, raw_inode, ei);
4987                 spin_unlock(&ei->i_raw_lock);
4988                 trace_ext4_other_inode_update_time(inode, orig_ino);
4989                 return;
4990         }
4991         spin_unlock(&inode->i_lock);
4992 }
4993
4994 /*
4995  * Opportunistically update the other time fields for other inodes in
4996  * the same inode table block.
4997  */
4998 static void ext4_update_other_inodes_time(struct super_block *sb,
4999                                           unsigned long orig_ino, char *buf)
5000 {
5001         unsigned long ino;
5002         int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
5003         int inode_size = EXT4_INODE_SIZE(sb);
5004
5005         /*
5006          * Calculate the first inode in the inode table block.  Inode
5007          * numbers are one-based.  That is, the first inode in a block
5008          * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
5009          */
5010         ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
5011         rcu_read_lock();
5012         for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
5013                 if (ino == orig_ino)
5014                         continue;
5015                 __ext4_update_other_inode_time(sb, orig_ino, ino,
5016                                                (struct ext4_inode *)buf);
5017         }
5018         rcu_read_unlock();
5019 }
5020
5021 /*
5022  * Post the struct inode info into an on-disk inode location in the
5023  * buffer-cache.  This gobbles the caller's reference to the
5024  * buffer_head in the inode location struct.
5025  *
5026  * The caller must have write access to iloc->bh.
5027  */
5028 static int ext4_do_update_inode(handle_t *handle,
5029                                 struct inode *inode,
5030                                 struct ext4_iloc *iloc)
5031 {
5032         struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5033         struct ext4_inode_info *ei = EXT4_I(inode);
5034         struct buffer_head *bh = iloc->bh;
5035         struct super_block *sb = inode->i_sb;
5036         int err = 0, block;
5037         int need_datasync = 0, set_large_file = 0;
5038         uid_t i_uid;
5039         gid_t i_gid;
5040         projid_t i_projid;
5041
5042         spin_lock(&ei->i_raw_lock);
5043
5044         /*
5045          * For fields not tracked in the in-memory inode, initialise them
5046          * to zero for new inodes.
5047          */
5048         if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5049                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5050
5051         err = ext4_inode_blocks_set(handle, raw_inode, ei);
5052
5053         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
5054         i_uid = i_uid_read(inode);
5055         i_gid = i_gid_read(inode);
5056         i_projid = from_kprojid(&init_user_ns, ei->i_projid);
5057         if (!(test_opt(inode->i_sb, NO_UID32))) {
5058                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
5059                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
5060                 /*
5061                  * Fix up interoperability with old kernels. Otherwise,
5062                  * old inodes get re-used with the upper 16 bits of the
5063                  * uid/gid intact.
5064                  */
5065                 if (ei->i_dtime && list_empty(&ei->i_orphan)) {
5066                         raw_inode->i_uid_high = 0;
5067                         raw_inode->i_gid_high = 0;
5068                 } else {
5069                         raw_inode->i_uid_high =
5070                                 cpu_to_le16(high_16_bits(i_uid));
5071                         raw_inode->i_gid_high =
5072                                 cpu_to_le16(high_16_bits(i_gid));
5073                 }
5074         } else {
5075                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
5076                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
5077                 raw_inode->i_uid_high = 0;
5078                 raw_inode->i_gid_high = 0;
5079         }
5080         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5081
5082         EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5083         EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5084         EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5085         EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5086
5087         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5088         raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
5089         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
5090                 raw_inode->i_file_acl_high =
5091                         cpu_to_le16(ei->i_file_acl >> 32);
5092         raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5093         if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode)) {
5094                 ext4_isize_set(raw_inode, ei->i_disksize);
5095                 need_datasync = 1;
5096         }
5097         if (ei->i_disksize > 0x7fffffffULL) {
5098                 if (!ext4_has_feature_large_file(sb) ||
5099                                 EXT4_SB(sb)->s_es->s_rev_level ==
5100                     cpu_to_le32(EXT4_GOOD_OLD_REV))
5101                         set_large_file = 1;
5102         }
5103         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5104         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5105                 if (old_valid_dev(inode->i_rdev)) {
5106                         raw_inode->i_block[0] =
5107                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
5108                         raw_inode->i_block[1] = 0;
5109                 } else {
5110                         raw_inode->i_block[0] = 0;
5111                         raw_inode->i_block[1] =
5112                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
5113                         raw_inode->i_block[2] = 0;
5114                 }
5115         } else if (!ext4_has_inline_data(inode)) {
5116                 for (block = 0; block < EXT4_N_BLOCKS; block++)
5117                         raw_inode->i_block[block] = ei->i_data[block];
5118         }
5119
5120         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
5121                 u64 ivers = ext4_inode_peek_iversion(inode);
5122
5123                 raw_inode->i_disk_version = cpu_to_le32(ivers);
5124                 if (ei->i_extra_isize) {
5125                         if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5126                                 raw_inode->i_version_hi =
5127                                         cpu_to_le32(ivers >> 32);
5128                         raw_inode->i_extra_isize =
5129                                 cpu_to_le16(ei->i_extra_isize);
5130                 }
5131         }
5132
5133         if (i_projid != EXT4_DEF_PROJID &&
5134             !ext4_has_feature_project(inode->i_sb))
5135                 err = err ?: -EFSCORRUPTED;
5136
5137         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
5138             EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
5139                 raw_inode->i_projid = cpu_to_le32(i_projid);
5140
5141         ext4_inode_csum_set(inode, raw_inode, ei);
5142         spin_unlock(&ei->i_raw_lock);
5143         if (err) {
5144                 EXT4_ERROR_INODE(inode, "corrupted inode contents");
5145                 goto out_brelse;
5146         }
5147
5148         if (inode->i_sb->s_flags & SB_LAZYTIME)
5149                 ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5150                                               bh->b_data);
5151
5152         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5153         err = ext4_handle_dirty_metadata(handle, NULL, bh);
5154         if (err)
5155                 goto out_error;
5156         ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5157         if (set_large_file) {
5158                 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5159                 err = ext4_journal_get_write_access(handle, sb,
5160                                                     EXT4_SB(sb)->s_sbh,
5161                                                     EXT4_JTR_NONE);
5162                 if (err)
5163                         goto out_error;
5164                 lock_buffer(EXT4_SB(sb)->s_sbh);
5165                 ext4_set_feature_large_file(sb);
5166                 ext4_superblock_csum_set(sb);
5167                 unlock_buffer(EXT4_SB(sb)->s_sbh);
5168                 ext4_handle_sync(handle);
5169                 err = ext4_handle_dirty_metadata(handle, NULL,
5170                                                  EXT4_SB(sb)->s_sbh);
5171         }
5172         ext4_update_inode_fsync_trans(handle, inode, need_datasync);
5173 out_error:
5174         ext4_std_error(inode->i_sb, err);
5175 out_brelse:
5176         brelse(bh);
5177         return err;
5178 }
5179
5180 /*
5181  * ext4_write_inode()
5182  *
5183  * We are called from a few places:
5184  *
5185  * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5186  *   Here, there will be no transaction running. We wait for any running
5187  *   transaction to commit.
5188  *
5189  * - Within flush work (sys_sync(), kupdate and such).
5190  *   We wait on commit, if told to.
5191  *
5192  * - Within iput_final() -> write_inode_now()
5193  *   We wait on commit, if told to.
5194  *
5195  * In all cases it is actually safe for us to return without doing anything,
5196  * because the inode has been copied into a raw inode buffer in
5197  * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5198  * writeback.
5199  *
5200  * Note that we are absolutely dependent upon all inode dirtiers doing the
5201  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5202  * which we are interested.
5203  *
5204  * It would be a bug for them to not do this.  The code:
5205  *
5206  *      mark_inode_dirty(inode)
5207  *      stuff();
5208  *      inode->i_size = expr;
5209  *
5210  * is in error because write_inode() could occur while `stuff()' is running,
5211  * and the new i_size will be lost.  Plus the inode will no longer be on the
5212  * superblock's dirty inode list.
5213  */
5214 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5215 {
5216         int err;
5217
5218         if (WARN_ON_ONCE(current->flags & PF_MEMALLOC) ||
5219             sb_rdonly(inode->i_sb))
5220                 return 0;
5221
5222         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5223                 return -EIO;
5224
5225         if (EXT4_SB(inode->i_sb)->s_journal) {
5226                 if (ext4_journal_current_handle()) {
5227                         jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5228                         dump_stack();
5229                         return -EIO;
5230                 }
5231
5232                 /*
5233                  * No need to force transaction in WB_SYNC_NONE mode. Also
5234                  * ext4_sync_fs() will force the commit after everything is
5235                  * written.
5236                  */
5237                 if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5238                         return 0;
5239
5240                 err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
5241                                                 EXT4_I(inode)->i_sync_tid);
5242         } else {
5243                 struct ext4_iloc iloc;
5244
5245                 err = __ext4_get_inode_loc_noinmem(inode, &iloc);
5246                 if (err)
5247                         return err;
5248                 /*
5249                  * sync(2) will flush the whole buffer cache. No need to do
5250                  * it here separately for each inode.
5251                  */
5252                 if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5253                         sync_dirty_buffer(iloc.bh);
5254                 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5255                         ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5256                                                "IO error syncing inode");
5257                         err = -EIO;
5258                 }
5259                 brelse(iloc.bh);
5260         }
5261         return err;
5262 }
5263
5264 /*
5265  * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
5266  * buffers that are attached to a page stradding i_size and are undergoing
5267  * commit. In that case we have to wait for commit to finish and try again.
5268  */
5269 static void ext4_wait_for_tail_page_commit(struct inode *inode)
5270 {
5271         struct page *page;
5272         unsigned offset;
5273         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5274         tid_t commit_tid = 0;
5275         int ret;
5276
5277         offset = inode->i_size & (PAGE_SIZE - 1);
5278         /*
5279          * If the page is fully truncated, we don't need to wait for any commit
5280          * (and we even should not as __ext4_journalled_invalidatepage() may
5281          * strip all buffers from the page but keep the page dirty which can then
5282          * confuse e.g. concurrent ext4_writepage() seeing dirty page without
5283          * buffers). Also we don't need to wait for any commit if all buffers in
5284          * the page remain valid. This is most beneficial for the common case of
5285          * blocksize == PAGESIZE.
5286          */
5287         if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
5288                 return;
5289         while (1) {
5290                 page = find_lock_page(inode->i_mapping,
5291                                       inode->i_size >> PAGE_SHIFT);
5292                 if (!page)
5293                         return;
5294                 ret = __ext4_journalled_invalidatepage(page, offset,
5295                                                 PAGE_SIZE - offset);
5296                 unlock_page(page);
5297                 put_page(page);
5298                 if (ret != -EBUSY)
5299                         return;
5300                 commit_tid = 0;
5301                 read_lock(&journal->j_state_lock);
5302                 if (journal->j_committing_transaction)
5303                         commit_tid = journal->j_committing_transaction->t_tid;
5304                 read_unlock(&journal->j_state_lock);
5305                 if (commit_tid)
5306                         jbd2_log_wait_commit(journal, commit_tid);
5307         }
5308 }
5309
5310 /*
5311  * ext4_setattr()
5312  *
5313  * Called from notify_change.
5314  *
5315  * We want to trap VFS attempts to truncate the file as soon as
5316  * possible.  In particular, we want to make sure that when the VFS
5317  * shrinks i_size, we put the inode on the orphan list and modify
5318  * i_disksize immediately, so that during the subsequent flushing of
5319  * dirty pages and freeing of disk blocks, we can guarantee that any
5320  * commit will leave the blocks being flushed in an unused state on
5321  * disk.  (On recovery, the inode will get truncated and the blocks will
5322  * be freed, so we have a strong guarantee that no future commit will
5323  * leave these blocks visible to the user.)
5324  *
5325  * Another thing we have to assure is that if we are in ordered mode
5326  * and inode is still attached to the committing transaction, we must
5327  * we start writeout of all the dirty pages which are being truncated.
5328  * This way we are sure that all the data written in the previous
5329  * transaction are already on disk (truncate waits for pages under
5330  * writeback).
5331  *
5332  * Called with inode->i_mutex down.
5333  */
5334 int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
5335                  struct iattr *attr)
5336 {
5337         struct inode *inode = d_inode(dentry);
5338         int error, rc = 0;
5339         int orphan = 0;
5340         const unsigned int ia_valid = attr->ia_valid;
5341
5342         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5343                 return -EIO;
5344
5345         if (unlikely(IS_IMMUTABLE(inode)))
5346                 return -EPERM;
5347
5348         if (unlikely(IS_APPEND(inode) &&
5349                      (ia_valid & (ATTR_MODE | ATTR_UID |
5350                                   ATTR_GID | ATTR_TIMES_SET))))
5351                 return -EPERM;
5352
5353         error = setattr_prepare(mnt_userns, dentry, attr);
5354         if (error)
5355                 return error;
5356
5357         error = fscrypt_prepare_setattr(dentry, attr);
5358         if (error)
5359                 return error;
5360
5361         error = fsverity_prepare_setattr(dentry, attr);
5362         if (error)
5363                 return error;
5364
5365         if (is_quota_modification(inode, attr)) {
5366                 error = dquot_initialize(inode);
5367                 if (error)
5368                         return error;
5369         }
5370         ext4_fc_start_update(inode);
5371         if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
5372             (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
5373                 handle_t *handle;
5374
5375                 /* (user+group)*(old+new) structure, inode write (sb,
5376                  * inode block, ? - but truncate inode update has it) */
5377                 handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5378                         (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5379                          EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5380                 if (IS_ERR(handle)) {
5381                         error = PTR_ERR(handle);
5382                         goto err_out;
5383                 }
5384
5385                 /* dquot_transfer() calls back ext4_get_inode_usage() which
5386                  * counts xattr inode references.
5387                  */
5388                 down_read(&EXT4_I(inode)->xattr_sem);
5389                 error = dquot_transfer(inode, attr);
5390                 up_read(&EXT4_I(inode)->xattr_sem);
5391
5392                 if (error) {
5393                         ext4_journal_stop(handle);
5394                         ext4_fc_stop_update(inode);
5395                         return error;
5396                 }
5397                 /* Update corresponding info in inode so that everything is in
5398                  * one transaction */
5399                 if (attr->ia_valid & ATTR_UID)
5400                         inode->i_uid = attr->ia_uid;
5401                 if (attr->ia_valid & ATTR_GID)
5402                         inode->i_gid = attr->ia_gid;
5403                 error = ext4_mark_inode_dirty(handle, inode);
5404                 ext4_journal_stop(handle);
5405                 if (unlikely(error)) {
5406                         ext4_fc_stop_update(inode);
5407                         return error;
5408                 }
5409         }
5410
5411         if (attr->ia_valid & ATTR_SIZE) {
5412                 handle_t *handle;
5413                 loff_t oldsize = inode->i_size;
5414                 int shrink = (attr->ia_size < inode->i_size);
5415
5416                 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5417                         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5418
5419                         if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5420                                 ext4_fc_stop_update(inode);
5421                                 return -EFBIG;
5422                         }
5423                 }
5424                 if (!S_ISREG(inode->i_mode)) {
5425                         ext4_fc_stop_update(inode);
5426                         return -EINVAL;
5427                 }
5428
5429                 if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5430                         inode_inc_iversion(inode);
5431
5432                 if (shrink) {
5433                         if (ext4_should_order_data(inode)) {
5434                                 error = ext4_begin_ordered_truncate(inode,
5435                                                             attr->ia_size);
5436                                 if (error)
5437                                         goto err_out;
5438                         }
5439                         /*
5440                          * Blocks are going to be removed from the inode. Wait
5441                          * for dio in flight.
5442                          */
5443                         inode_dio_wait(inode);
5444                 }
5445
5446                 filemap_invalidate_lock(inode->i_mapping);
5447
5448                 rc = ext4_break_layouts(inode);
5449                 if (rc) {
5450                         filemap_invalidate_unlock(inode->i_mapping);
5451                         goto err_out;
5452                 }
5453
5454                 if (attr->ia_size != inode->i_size) {
5455                         handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5456                         if (IS_ERR(handle)) {
5457                                 error = PTR_ERR(handle);
5458                                 goto out_mmap_sem;
5459                         }
5460                         if (ext4_handle_valid(handle) && shrink) {
5461                                 error = ext4_orphan_add(handle, inode);
5462                                 orphan = 1;
5463                         }
5464                         /*
5465                          * Update c/mtime on truncate up, ext4_truncate() will
5466                          * update c/mtime in shrink case below
5467                          */
5468                         if (!shrink) {
5469                                 inode->i_mtime = current_time(inode);
5470                                 inode->i_ctime = inode->i_mtime;
5471                         }
5472
5473                         if (shrink)
5474                                 ext4_fc_track_range(handle, inode,
5475                                         (attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5476                                         inode->i_sb->s_blocksize_bits,
5477                                         (oldsize > 0 ? oldsize - 1 : 0) >>
5478                                         inode->i_sb->s_blocksize_bits);
5479                         else
5480                                 ext4_fc_track_range(
5481                                         handle, inode,
5482                                         (oldsize > 0 ? oldsize - 1 : oldsize) >>
5483                                         inode->i_sb->s_blocksize_bits,
5484                                         (attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5485                                         inode->i_sb->s_blocksize_bits);
5486
5487                         down_write(&EXT4_I(inode)->i_data_sem);
5488                         EXT4_I(inode)->i_disksize = attr->ia_size;
5489                         rc = ext4_mark_inode_dirty(handle, inode);
5490                         if (!error)
5491                                 error = rc;
5492                         /*
5493                          * We have to update i_size under i_data_sem together
5494                          * with i_disksize to avoid races with writeback code
5495                          * running ext4_wb_update_i_disksize().
5496                          */
5497                         if (!error)
5498                                 i_size_write(inode, attr->ia_size);
5499                         up_write(&EXT4_I(inode)->i_data_sem);
5500                         ext4_journal_stop(handle);
5501                         if (error)
5502                                 goto out_mmap_sem;
5503                         if (!shrink) {
5504                                 pagecache_isize_extended(inode, oldsize,
5505                                                          inode->i_size);
5506                         } else if (ext4_should_journal_data(inode)) {
5507                                 ext4_wait_for_tail_page_commit(inode);
5508                         }
5509                 }
5510
5511                 /*
5512                  * Truncate pagecache after we've waited for commit
5513                  * in data=journal mode to make pages freeable.
5514                  */
5515                 truncate_pagecache(inode, inode->i_size);
5516                 /*
5517                  * Call ext4_truncate() even if i_size didn't change to
5518                  * truncate possible preallocated blocks.
5519                  */
5520                 if (attr->ia_size <= oldsize) {
5521                         rc = ext4_truncate(inode);
5522                         if (rc)
5523                                 error = rc;
5524                 }
5525 out_mmap_sem:
5526                 filemap_invalidate_unlock(inode->i_mapping);
5527         }
5528
5529         if (!error) {
5530                 setattr_copy(mnt_userns, inode, attr);
5531                 mark_inode_dirty(inode);
5532         }
5533
5534         /*
5535          * If the call to ext4_truncate failed to get a transaction handle at
5536          * all, we need to clean up the in-core orphan list manually.
5537          */
5538         if (orphan && inode->i_nlink)
5539                 ext4_orphan_del(NULL, inode);
5540
5541         if (!error && (ia_valid & ATTR_MODE))
5542                 rc = posix_acl_chmod(mnt_userns, inode, inode->i_mode);
5543
5544 err_out:
5545         if  (error)
5546                 ext4_std_error(inode->i_sb, error);
5547         if (!error)
5548                 error = rc;
5549         ext4_fc_stop_update(inode);
5550         return error;
5551 }
5552
5553 int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
5554                  struct kstat *stat, u32 request_mask, unsigned int query_flags)
5555 {
5556         struct inode *inode = d_inode(path->dentry);
5557         struct ext4_inode *raw_inode;
5558         struct ext4_inode_info *ei = EXT4_I(inode);
5559         unsigned int flags;
5560
5561         if ((request_mask & STATX_BTIME) &&
5562             EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
5563                 stat->result_mask |= STATX_BTIME;
5564                 stat->btime.tv_sec = ei->i_crtime.tv_sec;
5565                 stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5566         }
5567
5568         flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5569         if (flags & EXT4_APPEND_FL)
5570                 stat->attributes |= STATX_ATTR_APPEND;
5571         if (flags & EXT4_COMPR_FL)
5572                 stat->attributes |= STATX_ATTR_COMPRESSED;
5573         if (flags & EXT4_ENCRYPT_FL)
5574                 stat->attributes |= STATX_ATTR_ENCRYPTED;
5575         if (flags & EXT4_IMMUTABLE_FL)
5576                 stat->attributes |= STATX_ATTR_IMMUTABLE;
5577         if (flags & EXT4_NODUMP_FL)
5578                 stat->attributes |= STATX_ATTR_NODUMP;
5579         if (flags & EXT4_VERITY_FL)
5580                 stat->attributes |= STATX_ATTR_VERITY;
5581
5582         stat->attributes_mask |= (STATX_ATTR_APPEND |
5583                                   STATX_ATTR_COMPRESSED |
5584                                   STATX_ATTR_ENCRYPTED |
5585                                   STATX_ATTR_IMMUTABLE |
5586                                   STATX_ATTR_NODUMP |
5587                                   STATX_ATTR_VERITY);
5588
5589         generic_fillattr(mnt_userns, inode, stat);
5590         return 0;
5591 }
5592
5593 int ext4_file_getattr(struct user_namespace *mnt_userns,
5594                       const struct path *path, struct kstat *stat,
5595                       u32 request_mask, unsigned int query_flags)
5596 {
5597         struct inode *inode = d_inode(path->dentry);
5598         u64 delalloc_blocks;
5599
5600         ext4_getattr(mnt_userns, path, stat, request_mask, query_flags);
5601
5602         /*
5603          * If there is inline data in the inode, the inode will normally not
5604          * have data blocks allocated (it may have an external xattr block).
5605          * Report at least one sector for such files, so tools like tar, rsync,
5606          * others don't incorrectly think the file is completely sparse.
5607          */
5608         if (unlikely(ext4_has_inline_data(inode)))
5609                 stat->blocks += (stat->size + 511) >> 9;
5610
5611         /*
5612          * We can't update i_blocks if the block allocation is delayed
5613          * otherwise in the case of system crash before the real block
5614          * allocation is done, we will have i_blocks inconsistent with
5615          * on-disk file blocks.
5616          * We always keep i_blocks updated together with real
5617          * allocation. But to not confuse with user, stat
5618          * will return the blocks that include the delayed allocation
5619          * blocks for this file.
5620          */
5621         delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5622                                    EXT4_I(inode)->i_reserved_data_blocks);
5623         stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5624         return 0;
5625 }
5626
5627 static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5628                                    int pextents)
5629 {
5630         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5631                 return ext4_ind_trans_blocks(inode, lblocks);
5632         return ext4_ext_index_trans_blocks(inode, pextents);
5633 }
5634
5635 /*
5636  * Account for index blocks, block groups bitmaps and block group
5637  * descriptor blocks if modify datablocks and index blocks
5638  * worse case, the indexs blocks spread over different block groups
5639  *
5640  * If datablocks are discontiguous, they are possible to spread over
5641  * different block groups too. If they are contiguous, with flexbg,
5642  * they could still across block group boundary.
5643  *
5644  * Also account for superblock, inode, quota and xattr blocks
5645  */
5646 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5647                                   int pextents)
5648 {
5649         ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5650         int gdpblocks;
5651         int idxblocks;
5652         int ret = 0;
5653
5654         /*
5655          * How many index blocks need to touch to map @lblocks logical blocks
5656          * to @pextents physical extents?
5657          */
5658         idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5659
5660         ret = idxblocks;
5661
5662         /*
5663          * Now let's see how many group bitmaps and group descriptors need
5664          * to account
5665          */
5666         groups = idxblocks + pextents;
5667         gdpblocks = groups;
5668         if (groups > ngroups)
5669                 groups = ngroups;
5670         if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5671                 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5672
5673         /* bitmaps and block group descriptor blocks */
5674         ret += groups + gdpblocks;
5675
5676         /* Blocks for super block, inode, quota and xattr blocks */
5677         ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5678
5679         return ret;
5680 }
5681
5682 /*
5683  * Calculate the total number of credits to reserve to fit
5684  * the modification of a single pages into a single transaction,
5685  * which may include multiple chunks of block allocations.
5686  *
5687  * This could be called via ext4_write_begin()
5688  *
5689  * We need to consider the worse case, when
5690  * one new block per extent.
5691  */
5692 int ext4_writepage_trans_blocks(struct inode *inode)
5693 {
5694         int bpp = ext4_journal_blocks_per_page(inode);
5695         int ret;
5696
5697         ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5698
5699         /* Account for data blocks for journalled mode */
5700         if (ext4_should_journal_data(inode))
5701                 ret += bpp;
5702         return ret;
5703 }
5704
5705 /*
5706  * Calculate the journal credits for a chunk of data modification.
5707  *
5708  * This is called from DIO, fallocate or whoever calling
5709  * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5710  *
5711  * journal buffers for data blocks are not included here, as DIO
5712  * and fallocate do no need to journal data buffers.
5713  */
5714 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5715 {
5716         return ext4_meta_trans_blocks(inode, nrblocks, 1);
5717 }
5718
5719 /*
5720  * The caller must have previously called ext4_reserve_inode_write().
5721  * Give this, we know that the caller already has write access to iloc->bh.
5722  */
5723 int ext4_mark_iloc_dirty(handle_t *handle,
5724                          struct inode *inode, struct ext4_iloc *iloc)
5725 {
5726         int err = 0;
5727
5728         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
5729                 put_bh(iloc->bh);
5730                 return -EIO;
5731         }
5732         ext4_fc_track_inode(handle, inode);
5733
5734         if (IS_I_VERSION(inode))
5735                 inode_inc_iversion(inode);
5736
5737         /* the do_update_inode consumes one bh->b_count */
5738         get_bh(iloc->bh);
5739
5740         /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5741         err = ext4_do_update_inode(handle, inode, iloc);
5742         put_bh(iloc->bh);
5743         return err;
5744 }
5745
5746 /*
5747  * On success, We end up with an outstanding reference count against
5748  * iloc->bh.  This _must_ be cleaned up later.
5749  */
5750
5751 int
5752 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5753                          struct ext4_iloc *iloc)
5754 {
5755         int err;
5756
5757         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5758                 return -EIO;
5759
5760         err = ext4_get_inode_loc(inode, iloc);
5761         if (!err) {
5762                 BUFFER_TRACE(iloc->bh, "get_write_access");
5763                 err = ext4_journal_get_write_access(handle, inode->i_sb,
5764                                                     iloc->bh, EXT4_JTR_NONE);
5765                 if (err) {
5766                         brelse(iloc->bh);
5767                         iloc->bh = NULL;
5768                 }
5769         }
5770         ext4_std_error(inode->i_sb, err);
5771         return err;
5772 }
5773
5774 static int __ext4_expand_extra_isize(struct inode *inode,
5775                                      unsigned int new_extra_isize,
5776                                      struct ext4_iloc *iloc,
5777                                      handle_t *handle, int *no_expand)
5778 {
5779         struct ext4_inode *raw_inode;
5780         struct ext4_xattr_ibody_header *header;
5781         unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5782         struct ext4_inode_info *ei = EXT4_I(inode);
5783         int error;
5784
5785         /* this was checked at iget time, but double check for good measure */
5786         if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
5787             (ei->i_extra_isize & 3)) {
5788                 EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
5789                                  ei->i_extra_isize,
5790                                  EXT4_INODE_SIZE(inode->i_sb));
5791                 return -EFSCORRUPTED;
5792         }
5793         if ((new_extra_isize < ei->i_extra_isize) ||
5794             (new_extra_isize < 4) ||
5795             (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
5796                 return -EINVAL; /* Should never happen */
5797
5798         raw_inode = ext4_raw_inode(iloc);
5799
5800         header = IHDR(inode, raw_inode);
5801
5802         /* No extended attributes present */
5803         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5804             header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5805                 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5806                        EXT4_I(inode)->i_extra_isize, 0,
5807                        new_extra_isize - EXT4_I(inode)->i_extra_isize);
5808                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5809                 return 0;
5810         }
5811
5812         /* try to expand with EAs present */
5813         error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5814                                            raw_inode, handle);
5815         if (error) {
5816                 /*
5817                  * Inode size expansion failed; don't try again
5818                  */
5819                 *no_expand = 1;
5820         }
5821
5822         return error;
5823 }
5824
5825 /*
5826  * Expand an inode by new_extra_isize bytes.
5827  * Returns 0 on success or negative error number on failure.
5828  */
5829 static int ext4_try_to_expand_extra_isize(struct inode *inode,
5830                                           unsigned int new_extra_isize,
5831                                           struct ext4_iloc iloc,
5832                                           handle_t *handle)
5833 {
5834         int no_expand;
5835         int error;
5836
5837         if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5838                 return -EOVERFLOW;
5839
5840         /*
5841          * In nojournal mode, we can immediately attempt to expand
5842          * the inode.  When journaled, we first need to obtain extra
5843          * buffer credits since we may write into the EA block
5844          * with this same handle. If journal_extend fails, then it will
5845          * only result in a minor loss of functionality for that inode.
5846          * If this is felt to be critical, then e2fsck should be run to
5847          * force a large enough s_min_extra_isize.
5848          */
5849         if (ext4_journal_extend(handle,
5850                                 EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
5851                 return -ENOSPC;
5852
5853         if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5854                 return -EBUSY;
5855
5856         error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5857                                           handle, &no_expand);
5858         ext4_write_unlock_xattr(inode, &no_expand);
5859
5860         return error;
5861 }
5862
5863 int ext4_expand_extra_isize(struct inode *inode,
5864                             unsigned int new_extra_isize,
5865                             struct ext4_iloc *iloc)
5866 {
5867         handle_t *handle;
5868         int no_expand;
5869         int error, rc;
5870
5871         if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5872                 brelse(iloc->bh);
5873                 return -EOVERFLOW;
5874         }
5875
5876         handle = ext4_journal_start(inode, EXT4_HT_INODE,
5877                                     EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5878         if (IS_ERR(handle)) {
5879                 error = PTR_ERR(handle);
5880                 brelse(iloc->bh);
5881                 return error;
5882         }
5883
5884         ext4_write_lock_xattr(inode, &no_expand);
5885
5886         BUFFER_TRACE(iloc->bh, "get_write_access");
5887         error = ext4_journal_get_write_access(handle, inode->i_sb, iloc->bh,
5888                                               EXT4_JTR_NONE);
5889         if (error) {
5890                 brelse(iloc->bh);
5891                 goto out_unlock;
5892         }
5893
5894         error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5895                                           handle, &no_expand);
5896
5897         rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5898         if (!error)
5899                 error = rc;
5900
5901 out_unlock:
5902         ext4_write_unlock_xattr(inode, &no_expand);
5903         ext4_journal_stop(handle);
5904         return error;
5905 }
5906
5907 /*
5908  * What we do here is to mark the in-core inode as clean with respect to inode
5909  * dirtiness (it may still be data-dirty).
5910  * This means that the in-core inode may be reaped by prune_icache
5911  * without having to perform any I/O.  This is a very good thing,
5912  * because *any* task may call prune_icache - even ones which
5913  * have a transaction open against a different journal.
5914  *
5915  * Is this cheating?  Not really.  Sure, we haven't written the
5916  * inode out, but prune_icache isn't a user-visible syncing function.
5917  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5918  * we start and wait on commits.
5919  */
5920 int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
5921                                 const char *func, unsigned int line)
5922 {
5923         struct ext4_iloc iloc;
5924         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5925         int err;
5926
5927         might_sleep();
5928         trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5929         err = ext4_reserve_inode_write(handle, inode, &iloc);
5930         if (err)
5931                 goto out;
5932
5933         if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5934                 ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5935                                                iloc, handle);
5936
5937         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5938 out:
5939         if (unlikely(err))
5940                 ext4_error_inode_err(inode, func, line, 0, err,
5941                                         "mark_inode_dirty error");
5942         return err;
5943 }
5944
5945 /*
5946  * ext4_dirty_inode() is called from __mark_inode_dirty()
5947  *
5948  * We're really interested in the case where a file is being extended.
5949  * i_size has been changed by generic_commit_write() and we thus need
5950  * to include the updated inode in the current transaction.
5951  *
5952  * Also, dquot_alloc_block() will always dirty the inode when blocks
5953  * are allocated to the file.
5954  *
5955  * If the inode is marked synchronous, we don't honour that here - doing
5956  * so would cause a commit on atime updates, which we don't bother doing.
5957  * We handle synchronous inodes at the highest possible level.
5958  */
5959 void ext4_dirty_inode(struct inode *inode, int flags)
5960 {
5961         handle_t *handle;
5962
5963         handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5964         if (IS_ERR(handle))
5965                 return;
5966         ext4_mark_inode_dirty(handle, inode);
5967         ext4_journal_stop(handle);
5968 }
5969
5970 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5971 {
5972         journal_t *journal;
5973         handle_t *handle;
5974         int err;
5975         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5976
5977         /*
5978          * We have to be very careful here: changing a data block's
5979          * journaling status dynamically is dangerous.  If we write a
5980          * data block to the journal, change the status and then delete
5981          * that block, we risk forgetting to revoke the old log record
5982          * from the journal and so a subsequent replay can corrupt data.
5983          * So, first we make sure that the journal is empty and that
5984          * nobody is changing anything.
5985          */
5986
5987         journal = EXT4_JOURNAL(inode);
5988         if (!journal)
5989                 return 0;
5990         if (is_journal_aborted(journal))
5991                 return -EROFS;
5992
5993         /* Wait for all existing dio workers */
5994         inode_dio_wait(inode);
5995
5996         /*
5997          * Before flushing the journal and switching inode's aops, we have
5998          * to flush all dirty data the inode has. There can be outstanding
5999          * delayed allocations, there can be unwritten extents created by
6000          * fallocate or buffered writes in dioread_nolock mode covered by
6001          * dirty data which can be converted only after flushing the dirty
6002          * data (and journalled aops don't know how to handle these cases).
6003          */
6004         if (val) {
6005                 filemap_invalidate_lock(inode->i_mapping);
6006                 err = filemap_write_and_wait(inode->i_mapping);
6007                 if (err < 0) {
6008                         filemap_invalidate_unlock(inode->i_mapping);
6009                         return err;
6010                 }
6011         }
6012
6013         percpu_down_write(&sbi->s_writepages_rwsem);
6014         jbd2_journal_lock_updates(journal);
6015
6016         /*
6017          * OK, there are no updates running now, and all cached data is
6018          * synced to disk.  We are now in a completely consistent state
6019          * which doesn't have anything in the journal, and we know that
6020          * no filesystem updates are running, so it is safe to modify
6021          * the inode's in-core data-journaling state flag now.
6022          */
6023
6024         if (val)
6025                 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6026         else {
6027                 err = jbd2_journal_flush(journal, 0);
6028                 if (err < 0) {
6029                         jbd2_journal_unlock_updates(journal);
6030                         percpu_up_write(&sbi->s_writepages_rwsem);
6031                         return err;
6032                 }
6033                 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6034         }
6035         ext4_set_aops(inode);
6036
6037         jbd2_journal_unlock_updates(journal);
6038         percpu_up_write(&sbi->s_writepages_rwsem);
6039
6040         if (val)
6041                 filemap_invalidate_unlock(inode->i_mapping);
6042
6043         /* Finally we can mark the inode as dirty. */
6044
6045         handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
6046         if (IS_ERR(handle))
6047                 return PTR_ERR(handle);
6048
6049         ext4_fc_mark_ineligible(inode->i_sb,
6050                 EXT4_FC_REASON_JOURNAL_FLAG_CHANGE);
6051         err = ext4_mark_inode_dirty(handle, inode);
6052         ext4_handle_sync(handle);
6053         ext4_journal_stop(handle);
6054         ext4_std_error(inode->i_sb, err);
6055
6056         return err;
6057 }
6058
6059 static int ext4_bh_unmapped(handle_t *handle, struct inode *inode,
6060                             struct buffer_head *bh)
6061 {
6062         return !buffer_mapped(bh);
6063 }
6064
6065 vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
6066 {
6067         struct vm_area_struct *vma = vmf->vma;
6068         struct page *page = vmf->page;
6069         loff_t size;
6070         unsigned long len;
6071         int err;
6072         vm_fault_t ret;
6073         struct file *file = vma->vm_file;
6074         struct inode *inode = file_inode(file);
6075         struct address_space *mapping = inode->i_mapping;
6076         handle_t *handle;
6077         get_block_t *get_block;
6078         int retries = 0;
6079
6080         if (unlikely(IS_IMMUTABLE(inode)))
6081                 return VM_FAULT_SIGBUS;
6082
6083         sb_start_pagefault(inode->i_sb);
6084         file_update_time(vma->vm_file);
6085
6086         filemap_invalidate_lock_shared(mapping);
6087
6088         err = ext4_convert_inline_data(inode);
6089         if (err)
6090                 goto out_ret;
6091
6092         /*
6093          * On data journalling we skip straight to the transaction handle:
6094          * there's no delalloc; page truncated will be checked later; the
6095          * early return w/ all buffers mapped (calculates size/len) can't
6096          * be used; and there's no dioread_nolock, so only ext4_get_block.
6097          */
6098         if (ext4_should_journal_data(inode))
6099                 goto retry_alloc;
6100
6101         /* Delalloc case is easy... */
6102         if (test_opt(inode->i_sb, DELALLOC) &&
6103             !ext4_nonda_switch(inode->i_sb)) {
6104                 do {
6105                         err = block_page_mkwrite(vma, vmf,
6106                                                    ext4_da_get_block_prep);
6107                 } while (err == -ENOSPC &&
6108                        ext4_should_retry_alloc(inode->i_sb, &retries));
6109                 goto out_ret;
6110         }
6111
6112         lock_page(page);
6113         size = i_size_read(inode);
6114         /* Page got truncated from under us? */
6115         if (page->mapping != mapping || page_offset(page) > size) {
6116                 unlock_page(page);
6117                 ret = VM_FAULT_NOPAGE;
6118                 goto out;
6119         }
6120
6121         if (page->index == size >> PAGE_SHIFT)
6122                 len = size & ~PAGE_MASK;
6123         else
6124                 len = PAGE_SIZE;
6125         /*
6126          * Return if we have all the buffers mapped. This avoids the need to do
6127          * journal_start/journal_stop which can block and take a long time
6128          *
6129          * This cannot be done for data journalling, as we have to add the
6130          * inode to the transaction's list to writeprotect pages on commit.
6131          */
6132         if (page_has_buffers(page)) {
6133                 if (!ext4_walk_page_buffers(NULL, inode, page_buffers(page),
6134                                             0, len, NULL,
6135                                             ext4_bh_unmapped)) {
6136                         /* Wait so that we don't change page under IO */
6137                         wait_for_stable_page(page);
6138                         ret = VM_FAULT_LOCKED;
6139                         goto out;
6140                 }
6141         }
6142         unlock_page(page);
6143         /* OK, we need to fill the hole... */
6144         if (ext4_should_dioread_nolock(inode))
6145                 get_block = ext4_get_block_unwritten;
6146         else
6147                 get_block = ext4_get_block;
6148 retry_alloc:
6149         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6150                                     ext4_writepage_trans_blocks(inode));
6151         if (IS_ERR(handle)) {
6152                 ret = VM_FAULT_SIGBUS;
6153                 goto out;
6154         }
6155         /*
6156          * Data journalling can't use block_page_mkwrite() because it
6157          * will set_buffer_dirty() before do_journal_get_write_access()
6158          * thus might hit warning messages for dirty metadata buffers.
6159          */
6160         if (!ext4_should_journal_data(inode)) {
6161                 err = block_page_mkwrite(vma, vmf, get_block);
6162         } else {
6163                 lock_page(page);
6164                 size = i_size_read(inode);
6165                 /* Page got truncated from under us? */
6166                 if (page->mapping != mapping || page_offset(page) > size) {
6167                         ret = VM_FAULT_NOPAGE;
6168                         goto out_error;
6169                 }
6170
6171                 if (page->index == size >> PAGE_SHIFT)
6172                         len = size & ~PAGE_MASK;
6173                 else
6174                         len = PAGE_SIZE;
6175
6176                 err = __block_write_begin(page, 0, len, ext4_get_block);
6177                 if (!err) {
6178                         ret = VM_FAULT_SIGBUS;
6179                         if (ext4_walk_page_buffers(handle, inode,
6180                                         page_buffers(page), 0, len, NULL,
6181                                         do_journal_get_write_access))
6182                                 goto out_error;
6183                         if (ext4_walk_page_buffers(handle, inode,
6184                                         page_buffers(page), 0, len, NULL,
6185                                         write_end_fn))
6186                                 goto out_error;
6187                         if (ext4_jbd2_inode_add_write(handle, inode,
6188                                                       page_offset(page), len))
6189                                 goto out_error;
6190                         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
6191                 } else {
6192                         unlock_page(page);
6193                 }
6194         }
6195         ext4_journal_stop(handle);
6196         if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6197                 goto retry_alloc;
6198 out_ret:
6199         ret = block_page_mkwrite_return(err);
6200 out:
6201         filemap_invalidate_unlock_shared(mapping);
6202         sb_end_pagefault(inode->i_sb);
6203         return ret;
6204 out_error:
6205         unlock_page(page);
6206         ext4_journal_stop(handle);
6207         goto out;
6208 }