Merge tag 'sound-5.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...
[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         bool verity = ext4_verity_in_progress(inode);
1288
1289         trace_ext4_write_end(inode, pos, len, copied);
1290
1291         if (ext4_has_inline_data(inode))
1292                 return ext4_write_inline_data_end(inode, pos, len, copied, page);
1293
1294         copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1295         /*
1296          * it's important to update i_size while still holding page lock:
1297          * page writeout could otherwise come in and zero beyond i_size.
1298          *
1299          * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1300          * blocks are being written past EOF, so skip the i_size update.
1301          */
1302         if (!verity)
1303                 i_size_changed = ext4_update_inode_size(inode, pos + copied);
1304         unlock_page(page);
1305         put_page(page);
1306
1307         if (old_size < pos && !verity)
1308                 pagecache_isize_extended(inode, old_size, pos);
1309         /*
1310          * Don't mark the inode dirty under page lock. First, it unnecessarily
1311          * makes the holding time of page lock longer. Second, it forces lock
1312          * ordering of page lock and transaction start for journaling
1313          * filesystems.
1314          */
1315         if (i_size_changed)
1316                 ret = ext4_mark_inode_dirty(handle, inode);
1317
1318         if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1319                 /* if we have allocated more blocks and copied
1320                  * less. We will have blocks allocated outside
1321                  * inode->i_size. So truncate them
1322                  */
1323                 ext4_orphan_add(handle, inode);
1324
1325         ret2 = ext4_journal_stop(handle);
1326         if (!ret)
1327                 ret = ret2;
1328
1329         if (pos + len > inode->i_size && !verity) {
1330                 ext4_truncate_failed_write(inode);
1331                 /*
1332                  * If truncate failed early the inode might still be
1333                  * on the orphan list; we need to make sure the inode
1334                  * is removed from the orphan list in that case.
1335                  */
1336                 if (inode->i_nlink)
1337                         ext4_orphan_del(NULL, inode);
1338         }
1339
1340         return ret ? ret : copied;
1341 }
1342
1343 /*
1344  * This is a private version of page_zero_new_buffers() which doesn't
1345  * set the buffer to be dirty, since in data=journalled mode we need
1346  * to call ext4_handle_dirty_metadata() instead.
1347  */
1348 static void ext4_journalled_zero_new_buffers(handle_t *handle,
1349                                             struct inode *inode,
1350                                             struct page *page,
1351                                             unsigned from, unsigned to)
1352 {
1353         unsigned int block_start = 0, block_end;
1354         struct buffer_head *head, *bh;
1355
1356         bh = head = page_buffers(page);
1357         do {
1358                 block_end = block_start + bh->b_size;
1359                 if (buffer_new(bh)) {
1360                         if (block_end > from && block_start < to) {
1361                                 if (!PageUptodate(page)) {
1362                                         unsigned start, size;
1363
1364                                         start = max(from, block_start);
1365                                         size = min(to, block_end) - start;
1366
1367                                         zero_user(page, start, size);
1368                                         write_end_fn(handle, inode, bh);
1369                                 }
1370                                 clear_buffer_new(bh);
1371                         }
1372                 }
1373                 block_start = block_end;
1374                 bh = bh->b_this_page;
1375         } while (bh != head);
1376 }
1377
1378 static int ext4_journalled_write_end(struct file *file,
1379                                      struct address_space *mapping,
1380                                      loff_t pos, unsigned len, unsigned copied,
1381                                      struct page *page, void *fsdata)
1382 {
1383         handle_t *handle = ext4_journal_current_handle();
1384         struct inode *inode = mapping->host;
1385         loff_t old_size = inode->i_size;
1386         int ret = 0, ret2;
1387         int partial = 0;
1388         unsigned from, to;
1389         int size_changed = 0;
1390         bool verity = ext4_verity_in_progress(inode);
1391
1392         trace_ext4_journalled_write_end(inode, pos, len, copied);
1393         from = pos & (PAGE_SIZE - 1);
1394         to = from + len;
1395
1396         BUG_ON(!ext4_handle_valid(handle));
1397
1398         if (ext4_has_inline_data(inode))
1399                 return ext4_write_inline_data_end(inode, pos, len, copied, page);
1400
1401         if (unlikely(copied < len) && !PageUptodate(page)) {
1402                 copied = 0;
1403                 ext4_journalled_zero_new_buffers(handle, inode, page, from, to);
1404         } else {
1405                 if (unlikely(copied < len))
1406                         ext4_journalled_zero_new_buffers(handle, inode, page,
1407                                                          from + copied, to);
1408                 ret = ext4_walk_page_buffers(handle, inode, page_buffers(page),
1409                                              from, from + copied, &partial,
1410                                              write_end_fn);
1411                 if (!partial)
1412                         SetPageUptodate(page);
1413         }
1414         if (!verity)
1415                 size_changed = ext4_update_inode_size(inode, pos + copied);
1416         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1417         EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1418         unlock_page(page);
1419         put_page(page);
1420
1421         if (old_size < pos && !verity)
1422                 pagecache_isize_extended(inode, old_size, pos);
1423
1424         if (size_changed) {
1425                 ret2 = ext4_mark_inode_dirty(handle, inode);
1426                 if (!ret)
1427                         ret = ret2;
1428         }
1429
1430         if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1431                 /* if we have allocated more blocks and copied
1432                  * less. We will have blocks allocated outside
1433                  * inode->i_size. So truncate them
1434                  */
1435                 ext4_orphan_add(handle, inode);
1436
1437         ret2 = ext4_journal_stop(handle);
1438         if (!ret)
1439                 ret = ret2;
1440         if (pos + len > inode->i_size && !verity) {
1441                 ext4_truncate_failed_write(inode);
1442                 /*
1443                  * If truncate failed early the inode might still be
1444                  * on the orphan list; we need to make sure the inode
1445                  * is removed from the orphan list in that case.
1446                  */
1447                 if (inode->i_nlink)
1448                         ext4_orphan_del(NULL, inode);
1449         }
1450
1451         return ret ? ret : copied;
1452 }
1453
1454 /*
1455  * Reserve space for a single cluster
1456  */
1457 static int ext4_da_reserve_space(struct inode *inode)
1458 {
1459         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1460         struct ext4_inode_info *ei = EXT4_I(inode);
1461         int ret;
1462
1463         /*
1464          * We will charge metadata quota at writeout time; this saves
1465          * us from metadata over-estimation, though we may go over by
1466          * a small amount in the end.  Here we just reserve for data.
1467          */
1468         ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1469         if (ret)
1470                 return ret;
1471
1472         spin_lock(&ei->i_block_reservation_lock);
1473         if (ext4_claim_free_clusters(sbi, 1, 0)) {
1474                 spin_unlock(&ei->i_block_reservation_lock);
1475                 dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1476                 return -ENOSPC;
1477         }
1478         ei->i_reserved_data_blocks++;
1479         trace_ext4_da_reserve_space(inode);
1480         spin_unlock(&ei->i_block_reservation_lock);
1481
1482         return 0;       /* success */
1483 }
1484
1485 void ext4_da_release_space(struct inode *inode, int to_free)
1486 {
1487         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1488         struct ext4_inode_info *ei = EXT4_I(inode);
1489
1490         if (!to_free)
1491                 return;         /* Nothing to release, exit */
1492
1493         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1494
1495         trace_ext4_da_release_space(inode, to_free);
1496         if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1497                 /*
1498                  * if there aren't enough reserved blocks, then the
1499                  * counter is messed up somewhere.  Since this
1500                  * function is called from invalidate page, it's
1501                  * harmless to return without any action.
1502                  */
1503                 ext4_warning(inode->i_sb, "ext4_da_release_space: "
1504                          "ino %lu, to_free %d with only %d reserved "
1505                          "data blocks", inode->i_ino, to_free,
1506                          ei->i_reserved_data_blocks);
1507                 WARN_ON(1);
1508                 to_free = ei->i_reserved_data_blocks;
1509         }
1510         ei->i_reserved_data_blocks -= to_free;
1511
1512         /* update fs dirty data blocks counter */
1513         percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1514
1515         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1516
1517         dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1518 }
1519
1520 /*
1521  * Delayed allocation stuff
1522  */
1523
1524 struct mpage_da_data {
1525         struct inode *inode;
1526         struct writeback_control *wbc;
1527
1528         pgoff_t first_page;     /* The first page to write */
1529         pgoff_t next_page;      /* Current page to examine */
1530         pgoff_t last_page;      /* Last page to examine */
1531         /*
1532          * Extent to map - this can be after first_page because that can be
1533          * fully mapped. We somewhat abuse m_flags to store whether the extent
1534          * is delalloc or unwritten.
1535          */
1536         struct ext4_map_blocks map;
1537         struct ext4_io_submit io_submit;        /* IO submission data */
1538         unsigned int do_map:1;
1539         unsigned int scanned_until_end:1;
1540 };
1541
1542 static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1543                                        bool invalidate)
1544 {
1545         int nr_pages, i;
1546         pgoff_t index, end;
1547         struct pagevec pvec;
1548         struct inode *inode = mpd->inode;
1549         struct address_space *mapping = inode->i_mapping;
1550
1551         /* This is necessary when next_page == 0. */
1552         if (mpd->first_page >= mpd->next_page)
1553                 return;
1554
1555         mpd->scanned_until_end = 0;
1556         index = mpd->first_page;
1557         end   = mpd->next_page - 1;
1558         if (invalidate) {
1559                 ext4_lblk_t start, last;
1560                 start = index << (PAGE_SHIFT - inode->i_blkbits);
1561                 last = end << (PAGE_SHIFT - inode->i_blkbits);
1562                 ext4_es_remove_extent(inode, start, last - start + 1);
1563         }
1564
1565         pagevec_init(&pvec);
1566         while (index <= end) {
1567                 nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end);
1568                 if (nr_pages == 0)
1569                         break;
1570                 for (i = 0; i < nr_pages; i++) {
1571                         struct page *page = pvec.pages[i];
1572
1573                         BUG_ON(!PageLocked(page));
1574                         BUG_ON(PageWriteback(page));
1575                         if (invalidate) {
1576                                 if (page_mapped(page))
1577                                         clear_page_dirty_for_io(page);
1578                                 block_invalidatepage(page, 0, PAGE_SIZE);
1579                                 ClearPageUptodate(page);
1580                         }
1581                         unlock_page(page);
1582                 }
1583                 pagevec_release(&pvec);
1584         }
1585 }
1586
1587 static void ext4_print_free_blocks(struct inode *inode)
1588 {
1589         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1590         struct super_block *sb = inode->i_sb;
1591         struct ext4_inode_info *ei = EXT4_I(inode);
1592
1593         ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1594                EXT4_C2B(EXT4_SB(inode->i_sb),
1595                         ext4_count_free_clusters(sb)));
1596         ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1597         ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1598                (long long) EXT4_C2B(EXT4_SB(sb),
1599                 percpu_counter_sum(&sbi->s_freeclusters_counter)));
1600         ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1601                (long long) EXT4_C2B(EXT4_SB(sb),
1602                 percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1603         ext4_msg(sb, KERN_CRIT, "Block reservation details");
1604         ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1605                  ei->i_reserved_data_blocks);
1606         return;
1607 }
1608
1609 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct inode *inode,
1610                                       struct buffer_head *bh)
1611 {
1612         return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1613 }
1614
1615 /*
1616  * ext4_insert_delayed_block - adds a delayed block to the extents status
1617  *                             tree, incrementing the reserved cluster/block
1618  *                             count or making a pending reservation
1619  *                             where needed
1620  *
1621  * @inode - file containing the newly added block
1622  * @lblk - logical block to be added
1623  *
1624  * Returns 0 on success, negative error code on failure.
1625  */
1626 static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
1627 {
1628         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1629         int ret;
1630         bool allocated = false;
1631         bool reserved = false;
1632
1633         /*
1634          * If the cluster containing lblk is shared with a delayed,
1635          * written, or unwritten extent in a bigalloc file system, it's
1636          * already been accounted for and does not need to be reserved.
1637          * A pending reservation must be made for the cluster if it's
1638          * shared with a written or unwritten extent and doesn't already
1639          * have one.  Written and unwritten extents can be purged from the
1640          * extents status tree if the system is under memory pressure, so
1641          * it's necessary to examine the extent tree if a search of the
1642          * extents status tree doesn't get a match.
1643          */
1644         if (sbi->s_cluster_ratio == 1) {
1645                 ret = ext4_da_reserve_space(inode);
1646                 if (ret != 0)   /* ENOSPC */
1647                         goto errout;
1648                 reserved = true;
1649         } else {   /* bigalloc */
1650                 if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
1651                         if (!ext4_es_scan_clu(inode,
1652                                               &ext4_es_is_mapped, lblk)) {
1653                                 ret = ext4_clu_mapped(inode,
1654                                                       EXT4_B2C(sbi, lblk));
1655                                 if (ret < 0)
1656                                         goto errout;
1657                                 if (ret == 0) {
1658                                         ret = ext4_da_reserve_space(inode);
1659                                         if (ret != 0)   /* ENOSPC */
1660                                                 goto errout;
1661                                         reserved = true;
1662                                 } else {
1663                                         allocated = true;
1664                                 }
1665                         } else {
1666                                 allocated = true;
1667                         }
1668                 }
1669         }
1670
1671         ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
1672         if (ret && reserved)
1673                 ext4_da_release_space(inode, 1);
1674
1675 errout:
1676         return ret;
1677 }
1678
1679 /*
1680  * This function is grabs code from the very beginning of
1681  * ext4_map_blocks, but assumes that the caller is from delayed write
1682  * time. This function looks up the requested blocks and sets the
1683  * buffer delay bit under the protection of i_data_sem.
1684  */
1685 static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1686                               struct ext4_map_blocks *map,
1687                               struct buffer_head *bh)
1688 {
1689         struct extent_status es;
1690         int retval;
1691         sector_t invalid_block = ~((sector_t) 0xffff);
1692 #ifdef ES_AGGRESSIVE_TEST
1693         struct ext4_map_blocks orig_map;
1694
1695         memcpy(&orig_map, map, sizeof(*map));
1696 #endif
1697
1698         if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1699                 invalid_block = ~0;
1700
1701         map->m_flags = 0;
1702         ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1703                   (unsigned long) map->m_lblk);
1704
1705         /* Lookup extent status tree firstly */
1706         if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
1707                 if (ext4_es_is_hole(&es)) {
1708                         retval = 0;
1709                         down_read(&EXT4_I(inode)->i_data_sem);
1710                         goto add_delayed;
1711                 }
1712
1713                 /*
1714                  * the buffer head associated with a delayed and not unwritten
1715                  * block found in the extent status cache must contain an
1716                  * invalid block number and have its BH_New and BH_Delay bits
1717                  * set, reflecting the state assigned when the block was
1718                  * initially delayed allocated
1719                  */
1720                 if (ext4_es_is_delonly(&es)) {
1721                         BUG_ON(bh->b_blocknr != invalid_block);
1722                         BUG_ON(!buffer_new(bh));
1723                         BUG_ON(!buffer_delay(bh));
1724                         return 0;
1725                 }
1726
1727                 map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1728                 retval = es.es_len - (iblock - es.es_lblk);
1729                 if (retval > map->m_len)
1730                         retval = map->m_len;
1731                 map->m_len = retval;
1732                 if (ext4_es_is_written(&es))
1733                         map->m_flags |= EXT4_MAP_MAPPED;
1734                 else if (ext4_es_is_unwritten(&es))
1735                         map->m_flags |= EXT4_MAP_UNWRITTEN;
1736                 else
1737                         BUG();
1738
1739 #ifdef ES_AGGRESSIVE_TEST
1740                 ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1741 #endif
1742                 return retval;
1743         }
1744
1745         /*
1746          * Try to see if we can get the block without requesting a new
1747          * file system block.
1748          */
1749         down_read(&EXT4_I(inode)->i_data_sem);
1750         if (ext4_has_inline_data(inode))
1751                 retval = 0;
1752         else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1753                 retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1754         else
1755                 retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1756
1757 add_delayed:
1758         if (retval == 0) {
1759                 int ret;
1760
1761                 /*
1762                  * XXX: __block_prepare_write() unmaps passed block,
1763                  * is it OK?
1764                  */
1765
1766                 ret = ext4_insert_delayed_block(inode, map->m_lblk);
1767                 if (ret != 0) {
1768                         retval = ret;
1769                         goto out_unlock;
1770                 }
1771
1772                 map_bh(bh, inode->i_sb, invalid_block);
1773                 set_buffer_new(bh);
1774                 set_buffer_delay(bh);
1775         } else if (retval > 0) {
1776                 int ret;
1777                 unsigned int status;
1778
1779                 if (unlikely(retval != map->m_len)) {
1780                         ext4_warning(inode->i_sb,
1781                                      "ES len assertion failed for inode "
1782                                      "%lu: retval %d != map->m_len %d",
1783                                      inode->i_ino, retval, map->m_len);
1784                         WARN_ON(1);
1785                 }
1786
1787                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1788                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1789                 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1790                                             map->m_pblk, status);
1791                 if (ret != 0)
1792                         retval = ret;
1793         }
1794
1795 out_unlock:
1796         up_read((&EXT4_I(inode)->i_data_sem));
1797
1798         return retval;
1799 }
1800
1801 /*
1802  * This is a special get_block_t callback which is used by
1803  * ext4_da_write_begin().  It will either return mapped block or
1804  * reserve space for a single block.
1805  *
1806  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1807  * We also have b_blocknr = -1 and b_bdev initialized properly
1808  *
1809  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1810  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1811  * initialized properly.
1812  */
1813 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1814                            struct buffer_head *bh, int create)
1815 {
1816         struct ext4_map_blocks map;
1817         int ret = 0;
1818
1819         BUG_ON(create == 0);
1820         BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1821
1822         map.m_lblk = iblock;
1823         map.m_len = 1;
1824
1825         /*
1826          * first, we need to know whether the block is allocated already
1827          * preallocated blocks are unmapped but should treated
1828          * the same as allocated blocks.
1829          */
1830         ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1831         if (ret <= 0)
1832                 return ret;
1833
1834         map_bh(bh, inode->i_sb, map.m_pblk);
1835         ext4_update_bh_state(bh, map.m_flags);
1836
1837         if (buffer_unwritten(bh)) {
1838                 /* A delayed write to unwritten bh should be marked
1839                  * new and mapped.  Mapped ensures that we don't do
1840                  * get_block multiple times when we write to the same
1841                  * offset and new ensures that we do proper zero out
1842                  * for partial write.
1843                  */
1844                 set_buffer_new(bh);
1845                 set_buffer_mapped(bh);
1846         }
1847         return 0;
1848 }
1849
1850 static int bget_one(handle_t *handle, struct inode *inode,
1851                     struct buffer_head *bh)
1852 {
1853         get_bh(bh);
1854         return 0;
1855 }
1856
1857 static int bput_one(handle_t *handle, struct inode *inode,
1858                     struct buffer_head *bh)
1859 {
1860         put_bh(bh);
1861         return 0;
1862 }
1863
1864 static int __ext4_journalled_writepage(struct page *page,
1865                                        unsigned int len)
1866 {
1867         struct address_space *mapping = page->mapping;
1868         struct inode *inode = mapping->host;
1869         struct buffer_head *page_bufs = NULL;
1870         handle_t *handle = NULL;
1871         int ret = 0, err = 0;
1872         int inline_data = ext4_has_inline_data(inode);
1873         struct buffer_head *inode_bh = NULL;
1874
1875         ClearPageChecked(page);
1876
1877         if (inline_data) {
1878                 BUG_ON(page->index != 0);
1879                 BUG_ON(len > ext4_get_max_inline_size(inode));
1880                 inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1881                 if (inode_bh == NULL)
1882                         goto out;
1883         } else {
1884                 page_bufs = page_buffers(page);
1885                 if (!page_bufs) {
1886                         BUG();
1887                         goto out;
1888                 }
1889                 ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1890                                        NULL, bget_one);
1891         }
1892         /*
1893          * We need to release the page lock before we start the
1894          * journal, so grab a reference so the page won't disappear
1895          * out from under us.
1896          */
1897         get_page(page);
1898         unlock_page(page);
1899
1900         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1901                                     ext4_writepage_trans_blocks(inode));
1902         if (IS_ERR(handle)) {
1903                 ret = PTR_ERR(handle);
1904                 put_page(page);
1905                 goto out_no_pagelock;
1906         }
1907         BUG_ON(!ext4_handle_valid(handle));
1908
1909         lock_page(page);
1910         put_page(page);
1911         if (page->mapping != mapping) {
1912                 /* The page got truncated from under us */
1913                 ext4_journal_stop(handle);
1914                 ret = 0;
1915                 goto out;
1916         }
1917
1918         if (inline_data) {
1919                 ret = ext4_mark_inode_dirty(handle, inode);
1920         } else {
1921                 ret = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1922                                              NULL, do_journal_get_write_access);
1923
1924                 err = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1925                                              NULL, write_end_fn);
1926         }
1927         if (ret == 0)
1928                 ret = err;
1929         err = ext4_jbd2_inode_add_write(handle, inode, page_offset(page), len);
1930         if (ret == 0)
1931                 ret = err;
1932         EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1933         err = ext4_journal_stop(handle);
1934         if (!ret)
1935                 ret = err;
1936
1937         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1938 out:
1939         unlock_page(page);
1940 out_no_pagelock:
1941         if (!inline_data && page_bufs)
1942                 ext4_walk_page_buffers(NULL, inode, page_bufs, 0, len,
1943                                        NULL, bput_one);
1944         brelse(inode_bh);
1945         return ret;
1946 }
1947
1948 /*
1949  * Note that we don't need to start a transaction unless we're journaling data
1950  * because we should have holes filled from ext4_page_mkwrite(). We even don't
1951  * need to file the inode to the transaction's list in ordered mode because if
1952  * we are writing back data added by write(), the inode is already there and if
1953  * we are writing back data modified via mmap(), no one guarantees in which
1954  * transaction the data will hit the disk. In case we are journaling data, we
1955  * cannot start transaction directly because transaction start ranks above page
1956  * lock so we have to do some magic.
1957  *
1958  * This function can get called via...
1959  *   - ext4_writepages after taking page lock (have journal handle)
1960  *   - journal_submit_inode_data_buffers (no journal handle)
1961  *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1962  *   - grab_page_cache when doing write_begin (have journal handle)
1963  *
1964  * We don't do any block allocation in this function. If we have page with
1965  * multiple blocks we need to write those buffer_heads that are mapped. This
1966  * is important for mmaped based write. So if we do with blocksize 1K
1967  * truncate(f, 1024);
1968  * a = mmap(f, 0, 4096);
1969  * a[0] = 'a';
1970  * truncate(f, 4096);
1971  * we have in the page first buffer_head mapped via page_mkwrite call back
1972  * but other buffer_heads would be unmapped but dirty (dirty done via the
1973  * do_wp_page). So writepage should write the first block. If we modify
1974  * the mmap area beyond 1024 we will again get a page_fault and the
1975  * page_mkwrite callback will do the block allocation and mark the
1976  * buffer_heads mapped.
1977  *
1978  * We redirty the page if we have any buffer_heads that is either delay or
1979  * unwritten in the page.
1980  *
1981  * We can get recursively called as show below.
1982  *
1983  *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1984  *              ext4_writepage()
1985  *
1986  * But since we don't do any block allocation we should not deadlock.
1987  * Page also have the dirty flag cleared so we don't get recurive page_lock.
1988  */
1989 static int ext4_writepage(struct page *page,
1990                           struct writeback_control *wbc)
1991 {
1992         int ret = 0;
1993         loff_t size;
1994         unsigned int len;
1995         struct buffer_head *page_bufs = NULL;
1996         struct inode *inode = page->mapping->host;
1997         struct ext4_io_submit io_submit;
1998         bool keep_towrite = false;
1999
2000         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
2001                 inode->i_mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
2002                 unlock_page(page);
2003                 return -EIO;
2004         }
2005
2006         trace_ext4_writepage(page);
2007         size = i_size_read(inode);
2008         if (page->index == size >> PAGE_SHIFT &&
2009             !ext4_verity_in_progress(inode))
2010                 len = size & ~PAGE_MASK;
2011         else
2012                 len = PAGE_SIZE;
2013
2014         page_bufs = page_buffers(page);
2015         /*
2016          * We cannot do block allocation or other extent handling in this
2017          * function. If there are buffers needing that, we have to redirty
2018          * the page. But we may reach here when we do a journal commit via
2019          * journal_submit_inode_data_buffers() and in that case we must write
2020          * allocated buffers to achieve data=ordered mode guarantees.
2021          *
2022          * Also, if there is only one buffer per page (the fs block
2023          * size == the page size), if one buffer needs block
2024          * allocation or needs to modify the extent tree to clear the
2025          * unwritten flag, we know that the page can't be written at
2026          * all, so we might as well refuse the write immediately.
2027          * Unfortunately if the block size != page size, we can't as
2028          * easily detect this case using ext4_walk_page_buffers(), but
2029          * for the extremely common case, this is an optimization that
2030          * skips a useless round trip through ext4_bio_write_page().
2031          */
2032         if (ext4_walk_page_buffers(NULL, inode, page_bufs, 0, len, NULL,
2033                                    ext4_bh_delay_or_unwritten)) {
2034                 redirty_page_for_writepage(wbc, page);
2035                 if ((current->flags & PF_MEMALLOC) ||
2036                     (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2037                         /*
2038                          * For memory cleaning there's no point in writing only
2039                          * some buffers. So just bail out. Warn if we came here
2040                          * from direct reclaim.
2041                          */
2042                         WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2043                                                         == PF_MEMALLOC);
2044                         unlock_page(page);
2045                         return 0;
2046                 }
2047                 keep_towrite = true;
2048         }
2049
2050         if (PageChecked(page) && ext4_should_journal_data(inode))
2051                 /*
2052                  * It's mmapped pagecache.  Add buffers and journal it.  There
2053                  * doesn't seem much point in redirtying the page here.
2054                  */
2055                 return __ext4_journalled_writepage(page, len);
2056
2057         ext4_io_submit_init(&io_submit, wbc);
2058         io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2059         if (!io_submit.io_end) {
2060                 redirty_page_for_writepage(wbc, page);
2061                 unlock_page(page);
2062                 return -ENOMEM;
2063         }
2064         ret = ext4_bio_write_page(&io_submit, page, len, keep_towrite);
2065         ext4_io_submit(&io_submit);
2066         /* Drop io_end reference we got from init */
2067         ext4_put_io_end_defer(io_submit.io_end);
2068         return ret;
2069 }
2070
2071 static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2072 {
2073         int len;
2074         loff_t size;
2075         int err;
2076
2077         BUG_ON(page->index != mpd->first_page);
2078         clear_page_dirty_for_io(page);
2079         /*
2080          * We have to be very careful here!  Nothing protects writeback path
2081          * against i_size changes and the page can be writeably mapped into
2082          * page tables. So an application can be growing i_size and writing
2083          * data through mmap while writeback runs. clear_page_dirty_for_io()
2084          * write-protects our page in page tables and the page cannot get
2085          * written to again until we release page lock. So only after
2086          * clear_page_dirty_for_io() we are safe to sample i_size for
2087          * ext4_bio_write_page() to zero-out tail of the written page. We rely
2088          * on the barrier provided by TestClearPageDirty in
2089          * clear_page_dirty_for_io() to make sure i_size is really sampled only
2090          * after page tables are updated.
2091          */
2092         size = i_size_read(mpd->inode);
2093         if (page->index == size >> PAGE_SHIFT &&
2094             !ext4_verity_in_progress(mpd->inode))
2095                 len = size & ~PAGE_MASK;
2096         else
2097                 len = PAGE_SIZE;
2098         err = ext4_bio_write_page(&mpd->io_submit, page, len, false);
2099         if (!err)
2100                 mpd->wbc->nr_to_write--;
2101         mpd->first_page++;
2102
2103         return err;
2104 }
2105
2106 #define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
2107
2108 /*
2109  * mballoc gives us at most this number of blocks...
2110  * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2111  * The rest of mballoc seems to handle chunks up to full group size.
2112  */
2113 #define MAX_WRITEPAGES_EXTENT_LEN 2048
2114
2115 /*
2116  * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2117  *
2118  * @mpd - extent of blocks
2119  * @lblk - logical number of the block in the file
2120  * @bh - buffer head we want to add to the extent
2121  *
2122  * The function is used to collect contig. blocks in the same state. If the
2123  * buffer doesn't require mapping for writeback and we haven't started the
2124  * extent of buffers to map yet, the function returns 'true' immediately - the
2125  * caller can write the buffer right away. Otherwise the function returns true
2126  * if the block has been added to the extent, false if the block couldn't be
2127  * added.
2128  */
2129 static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2130                                    struct buffer_head *bh)
2131 {
2132         struct ext4_map_blocks *map = &mpd->map;
2133
2134         /* Buffer that doesn't need mapping for writeback? */
2135         if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2136             (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2137                 /* So far no extent to map => we write the buffer right away */
2138                 if (map->m_len == 0)
2139                         return true;
2140                 return false;
2141         }
2142
2143         /* First block in the extent? */
2144         if (map->m_len == 0) {
2145                 /* We cannot map unless handle is started... */
2146                 if (!mpd->do_map)
2147                         return false;
2148                 map->m_lblk = lblk;
2149                 map->m_len = 1;
2150                 map->m_flags = bh->b_state & BH_FLAGS;
2151                 return true;
2152         }
2153
2154         /* Don't go larger than mballoc is willing to allocate */
2155         if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2156                 return false;
2157
2158         /* Can we merge the block to our big extent? */
2159         if (lblk == map->m_lblk + map->m_len &&
2160             (bh->b_state & BH_FLAGS) == map->m_flags) {
2161                 map->m_len++;
2162                 return true;
2163         }
2164         return false;
2165 }
2166
2167 /*
2168  * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2169  *
2170  * @mpd - extent of blocks for mapping
2171  * @head - the first buffer in the page
2172  * @bh - buffer we should start processing from
2173  * @lblk - logical number of the block in the file corresponding to @bh
2174  *
2175  * Walk through page buffers from @bh upto @head (exclusive) and either submit
2176  * the page for IO if all buffers in this page were mapped and there's no
2177  * accumulated extent of buffers to map or add buffers in the page to the
2178  * extent of buffers to map. The function returns 1 if the caller can continue
2179  * by processing the next page, 0 if it should stop adding buffers to the
2180  * extent to map because we cannot extend it anymore. It can also return value
2181  * < 0 in case of error during IO submission.
2182  */
2183 static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2184                                    struct buffer_head *head,
2185                                    struct buffer_head *bh,
2186                                    ext4_lblk_t lblk)
2187 {
2188         struct inode *inode = mpd->inode;
2189         int err;
2190         ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
2191                                                         >> inode->i_blkbits;
2192
2193         if (ext4_verity_in_progress(inode))
2194                 blocks = EXT_MAX_BLOCKS;
2195
2196         do {
2197                 BUG_ON(buffer_locked(bh));
2198
2199                 if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2200                         /* Found extent to map? */
2201                         if (mpd->map.m_len)
2202                                 return 0;
2203                         /* Buffer needs mapping and handle is not started? */
2204                         if (!mpd->do_map)
2205                                 return 0;
2206                         /* Everything mapped so far and we hit EOF */
2207                         break;
2208                 }
2209         } while (lblk++, (bh = bh->b_this_page) != head);
2210         /* So far everything mapped? Submit the page for IO. */
2211         if (mpd->map.m_len == 0) {
2212                 err = mpage_submit_page(mpd, head->b_page);
2213                 if (err < 0)
2214                         return err;
2215         }
2216         if (lblk >= blocks) {
2217                 mpd->scanned_until_end = 1;
2218                 return 0;
2219         }
2220         return 1;
2221 }
2222
2223 /*
2224  * mpage_process_page - update page buffers corresponding to changed extent and
2225  *                     may submit fully mapped page for IO
2226  *
2227  * @mpd         - description of extent to map, on return next extent to map
2228  * @m_lblk      - logical block mapping.
2229  * @m_pblk      - corresponding physical mapping.
2230  * @map_bh      - determines on return whether this page requires any further
2231  *                mapping or not.
2232  * Scan given page buffers corresponding to changed extent and update buffer
2233  * state according to new extent state.
2234  * We map delalloc buffers to their physical location, clear unwritten bits.
2235  * If the given page is not fully mapped, we update @map to the next extent in
2236  * the given page that needs mapping & return @map_bh as true.
2237  */
2238 static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
2239                               ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
2240                               bool *map_bh)
2241 {
2242         struct buffer_head *head, *bh;
2243         ext4_io_end_t *io_end = mpd->io_submit.io_end;
2244         ext4_lblk_t lblk = *m_lblk;
2245         ext4_fsblk_t pblock = *m_pblk;
2246         int err = 0;
2247         int blkbits = mpd->inode->i_blkbits;
2248         ssize_t io_end_size = 0;
2249         struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2250
2251         bh = head = page_buffers(page);
2252         do {
2253                 if (lblk < mpd->map.m_lblk)
2254                         continue;
2255                 if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2256                         /*
2257                          * Buffer after end of mapped extent.
2258                          * Find next buffer in the page to map.
2259                          */
2260                         mpd->map.m_len = 0;
2261                         mpd->map.m_flags = 0;
2262                         io_end_vec->size += io_end_size;
2263                         io_end_size = 0;
2264
2265                         err = mpage_process_page_bufs(mpd, head, bh, lblk);
2266                         if (err > 0)
2267                                 err = 0;
2268                         if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2269                                 io_end_vec = ext4_alloc_io_end_vec(io_end);
2270                                 if (IS_ERR(io_end_vec)) {
2271                                         err = PTR_ERR(io_end_vec);
2272                                         goto out;
2273                                 }
2274                                 io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
2275                         }
2276                         *map_bh = true;
2277                         goto out;
2278                 }
2279                 if (buffer_delay(bh)) {
2280                         clear_buffer_delay(bh);
2281                         bh->b_blocknr = pblock++;
2282                 }
2283                 clear_buffer_unwritten(bh);
2284                 io_end_size += (1 << blkbits);
2285         } while (lblk++, (bh = bh->b_this_page) != head);
2286
2287         io_end_vec->size += io_end_size;
2288         io_end_size = 0;
2289         *map_bh = false;
2290 out:
2291         *m_lblk = lblk;
2292         *m_pblk = pblock;
2293         return err;
2294 }
2295
2296 /*
2297  * mpage_map_buffers - update buffers corresponding to changed extent and
2298  *                     submit fully mapped pages for IO
2299  *
2300  * @mpd - description of extent to map, on return next extent to map
2301  *
2302  * Scan buffers corresponding to changed extent (we expect corresponding pages
2303  * to be already locked) and update buffer state according to new extent state.
2304  * We map delalloc buffers to their physical location, clear unwritten bits,
2305  * and mark buffers as uninit when we perform writes to unwritten extents
2306  * and do extent conversion after IO is finished. If the last page is not fully
2307  * mapped, we update @map to the next extent in the last page that needs
2308  * mapping. Otherwise we submit the page for IO.
2309  */
2310 static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2311 {
2312         struct pagevec pvec;
2313         int nr_pages, i;
2314         struct inode *inode = mpd->inode;
2315         int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2316         pgoff_t start, end;
2317         ext4_lblk_t lblk;
2318         ext4_fsblk_t pblock;
2319         int err;
2320         bool map_bh = false;
2321
2322         start = mpd->map.m_lblk >> bpp_bits;
2323         end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2324         lblk = start << bpp_bits;
2325         pblock = mpd->map.m_pblk;
2326
2327         pagevec_init(&pvec);
2328         while (start <= end) {
2329                 nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
2330                                                 &start, end);
2331                 if (nr_pages == 0)
2332                         break;
2333                 for (i = 0; i < nr_pages; i++) {
2334                         struct page *page = pvec.pages[i];
2335
2336                         err = mpage_process_page(mpd, page, &lblk, &pblock,
2337                                                  &map_bh);
2338                         /*
2339                          * If map_bh is true, means page may require further bh
2340                          * mapping, or maybe the page was submitted for IO.
2341                          * So we return to call further extent mapping.
2342                          */
2343                         if (err < 0 || map_bh)
2344                                 goto out;
2345                         /* Page fully mapped - let IO run! */
2346                         err = mpage_submit_page(mpd, page);
2347                         if (err < 0)
2348                                 goto out;
2349                 }
2350                 pagevec_release(&pvec);
2351         }
2352         /* Extent fully mapped and matches with page boundary. We are done. */
2353         mpd->map.m_len = 0;
2354         mpd->map.m_flags = 0;
2355         return 0;
2356 out:
2357         pagevec_release(&pvec);
2358         return err;
2359 }
2360
2361 static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2362 {
2363         struct inode *inode = mpd->inode;
2364         struct ext4_map_blocks *map = &mpd->map;
2365         int get_blocks_flags;
2366         int err, dioread_nolock;
2367
2368         trace_ext4_da_write_pages_extent(inode, map);
2369         /*
2370          * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2371          * to convert an unwritten extent to be initialized (in the case
2372          * where we have written into one or more preallocated blocks).  It is
2373          * possible that we're going to need more metadata blocks than
2374          * previously reserved. However we must not fail because we're in
2375          * writeback and there is nothing we can do about it so it might result
2376          * in data loss.  So use reserved blocks to allocate metadata if
2377          * possible.
2378          *
2379          * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2380          * the blocks in question are delalloc blocks.  This indicates
2381          * that the blocks and quotas has already been checked when
2382          * the data was copied into the page cache.
2383          */
2384         get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2385                            EXT4_GET_BLOCKS_METADATA_NOFAIL |
2386                            EXT4_GET_BLOCKS_IO_SUBMIT;
2387         dioread_nolock = ext4_should_dioread_nolock(inode);
2388         if (dioread_nolock)
2389                 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2390         if (map->m_flags & BIT(BH_Delay))
2391                 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2392
2393         err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2394         if (err < 0)
2395                 return err;
2396         if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2397                 if (!mpd->io_submit.io_end->handle &&
2398                     ext4_handle_valid(handle)) {
2399                         mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2400                         handle->h_rsv_handle = NULL;
2401                 }
2402                 ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2403         }
2404
2405         BUG_ON(map->m_len == 0);
2406         return 0;
2407 }
2408
2409 /*
2410  * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2411  *                               mpd->len and submit pages underlying it for IO
2412  *
2413  * @handle - handle for journal operations
2414  * @mpd - extent to map
2415  * @give_up_on_write - we set this to true iff there is a fatal error and there
2416  *                     is no hope of writing the data. The caller should discard
2417  *                     dirty pages to avoid infinite loops.
2418  *
2419  * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2420  * delayed, blocks are allocated, if it is unwritten, we may need to convert
2421  * them to initialized or split the described range from larger unwritten
2422  * extent. Note that we need not map all the described range since allocation
2423  * can return less blocks or the range is covered by more unwritten extents. We
2424  * cannot map more because we are limited by reserved transaction credits. On
2425  * the other hand we always make sure that the last touched page is fully
2426  * mapped so that it can be written out (and thus forward progress is
2427  * guaranteed). After mapping we submit all mapped pages for IO.
2428  */
2429 static int mpage_map_and_submit_extent(handle_t *handle,
2430                                        struct mpage_da_data *mpd,
2431                                        bool *give_up_on_write)
2432 {
2433         struct inode *inode = mpd->inode;
2434         struct ext4_map_blocks *map = &mpd->map;
2435         int err;
2436         loff_t disksize;
2437         int progress = 0;
2438         ext4_io_end_t *io_end = mpd->io_submit.io_end;
2439         struct ext4_io_end_vec *io_end_vec;
2440
2441         io_end_vec = ext4_alloc_io_end_vec(io_end);
2442         if (IS_ERR(io_end_vec))
2443                 return PTR_ERR(io_end_vec);
2444         io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2445         do {
2446                 err = mpage_map_one_extent(handle, mpd);
2447                 if (err < 0) {
2448                         struct super_block *sb = inode->i_sb;
2449
2450                         if (ext4_forced_shutdown(EXT4_SB(sb)) ||
2451                             ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
2452                                 goto invalidate_dirty_pages;
2453                         /*
2454                          * Let the uper layers retry transient errors.
2455                          * In the case of ENOSPC, if ext4_count_free_blocks()
2456                          * is non-zero, a commit should free up blocks.
2457                          */
2458                         if ((err == -ENOMEM) ||
2459                             (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2460                                 if (progress)
2461                                         goto update_disksize;
2462                                 return err;
2463                         }
2464                         ext4_msg(sb, KERN_CRIT,
2465                                  "Delayed block allocation failed for "
2466                                  "inode %lu at logical offset %llu with"
2467                                  " max blocks %u with error %d",
2468                                  inode->i_ino,
2469                                  (unsigned long long)map->m_lblk,
2470                                  (unsigned)map->m_len, -err);
2471                         ext4_msg(sb, KERN_CRIT,
2472                                  "This should not happen!! Data will "
2473                                  "be lost\n");
2474                         if (err == -ENOSPC)
2475                                 ext4_print_free_blocks(inode);
2476                 invalidate_dirty_pages:
2477                         *give_up_on_write = true;
2478                         return err;
2479                 }
2480                 progress = 1;
2481                 /*
2482                  * Update buffer state, submit mapped pages, and get us new
2483                  * extent to map
2484                  */
2485                 err = mpage_map_and_submit_buffers(mpd);
2486                 if (err < 0)
2487                         goto update_disksize;
2488         } while (map->m_len);
2489
2490 update_disksize:
2491         /*
2492          * Update on-disk size after IO is submitted.  Races with
2493          * truncate are avoided by checking i_size under i_data_sem.
2494          */
2495         disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2496         if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2497                 int err2;
2498                 loff_t i_size;
2499
2500                 down_write(&EXT4_I(inode)->i_data_sem);
2501                 i_size = i_size_read(inode);
2502                 if (disksize > i_size)
2503                         disksize = i_size;
2504                 if (disksize > EXT4_I(inode)->i_disksize)
2505                         EXT4_I(inode)->i_disksize = disksize;
2506                 up_write(&EXT4_I(inode)->i_data_sem);
2507                 err2 = ext4_mark_inode_dirty(handle, inode);
2508                 if (err2) {
2509                         ext4_error_err(inode->i_sb, -err2,
2510                                        "Failed to mark inode %lu dirty",
2511                                        inode->i_ino);
2512                 }
2513                 if (!err)
2514                         err = err2;
2515         }
2516         return err;
2517 }
2518
2519 /*
2520  * Calculate the total number of credits to reserve for one writepages
2521  * iteration. This is called from ext4_writepages(). We map an extent of
2522  * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2523  * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2524  * bpp - 1 blocks in bpp different extents.
2525  */
2526 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2527 {
2528         int bpp = ext4_journal_blocks_per_page(inode);
2529
2530         return ext4_meta_trans_blocks(inode,
2531                                 MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2532 }
2533
2534 /*
2535  * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2536  *                               and underlying extent to map
2537  *
2538  * @mpd - where to look for pages
2539  *
2540  * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2541  * IO immediately. When we find a page which isn't mapped we start accumulating
2542  * extent of buffers underlying these pages that needs mapping (formed by
2543  * either delayed or unwritten buffers). We also lock the pages containing
2544  * these buffers. The extent found is returned in @mpd structure (starting at
2545  * mpd->lblk with length mpd->len blocks).
2546  *
2547  * Note that this function can attach bios to one io_end structure which are
2548  * neither logically nor physically contiguous. Although it may seem as an
2549  * unnecessary complication, it is actually inevitable in blocksize < pagesize
2550  * case as we need to track IO to all buffers underlying a page in one io_end.
2551  */
2552 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2553 {
2554         struct address_space *mapping = mpd->inode->i_mapping;
2555         struct pagevec pvec;
2556         unsigned int nr_pages;
2557         long left = mpd->wbc->nr_to_write;
2558         pgoff_t index = mpd->first_page;
2559         pgoff_t end = mpd->last_page;
2560         xa_mark_t tag;
2561         int i, err = 0;
2562         int blkbits = mpd->inode->i_blkbits;
2563         ext4_lblk_t lblk;
2564         struct buffer_head *head;
2565
2566         if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2567                 tag = PAGECACHE_TAG_TOWRITE;
2568         else
2569                 tag = PAGECACHE_TAG_DIRTY;
2570
2571         pagevec_init(&pvec);
2572         mpd->map.m_len = 0;
2573         mpd->next_page = index;
2574         while (index <= end) {
2575                 nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
2576                                 tag);
2577                 if (nr_pages == 0)
2578                         break;
2579
2580                 for (i = 0; i < nr_pages; i++) {
2581                         struct page *page = pvec.pages[i];
2582
2583                         /*
2584                          * Accumulated enough dirty pages? This doesn't apply
2585                          * to WB_SYNC_ALL mode. For integrity sync we have to
2586                          * keep going because someone may be concurrently
2587                          * dirtying pages, and we might have synced a lot of
2588                          * newly appeared dirty pages, but have not synced all
2589                          * of the old dirty pages.
2590                          */
2591                         if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2592                                 goto out;
2593
2594                         /* If we can't merge this page, we are done. */
2595                         if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2596                                 goto out;
2597
2598                         lock_page(page);
2599                         /*
2600                          * If the page is no longer dirty, or its mapping no
2601                          * longer corresponds to inode we are writing (which
2602                          * means it has been truncated or invalidated), or the
2603                          * page is already under writeback and we are not doing
2604                          * a data integrity writeback, skip the page
2605                          */
2606                         if (!PageDirty(page) ||
2607                             (PageWriteback(page) &&
2608                              (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2609                             unlikely(page->mapping != mapping)) {
2610                                 unlock_page(page);
2611                                 continue;
2612                         }
2613
2614                         wait_on_page_writeback(page);
2615                         BUG_ON(PageWriteback(page));
2616
2617                         if (mpd->map.m_len == 0)
2618                                 mpd->first_page = page->index;
2619                         mpd->next_page = page->index + 1;
2620                         /* Add all dirty buffers to mpd */
2621                         lblk = ((ext4_lblk_t)page->index) <<
2622                                 (PAGE_SHIFT - blkbits);
2623                         head = page_buffers(page);
2624                         err = mpage_process_page_bufs(mpd, head, head, lblk);
2625                         if (err <= 0)
2626                                 goto out;
2627                         err = 0;
2628                         left--;
2629                 }
2630                 pagevec_release(&pvec);
2631                 cond_resched();
2632         }
2633         mpd->scanned_until_end = 1;
2634         return 0;
2635 out:
2636         pagevec_release(&pvec);
2637         return err;
2638 }
2639
2640 static int ext4_writepages(struct address_space *mapping,
2641                            struct writeback_control *wbc)
2642 {
2643         pgoff_t writeback_index = 0;
2644         long nr_to_write = wbc->nr_to_write;
2645         int range_whole = 0;
2646         int cycled = 1;
2647         handle_t *handle = NULL;
2648         struct mpage_da_data mpd;
2649         struct inode *inode = mapping->host;
2650         int needed_blocks, rsv_blocks = 0, ret = 0;
2651         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2652         struct blk_plug plug;
2653         bool give_up_on_write = false;
2654
2655         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2656                 return -EIO;
2657
2658         percpu_down_read(&sbi->s_writepages_rwsem);
2659         trace_ext4_writepages(inode, wbc);
2660
2661         /*
2662          * No pages to write? This is mainly a kludge to avoid starting
2663          * a transaction for special inodes like journal inode on last iput()
2664          * because that could violate lock ordering on umount
2665          */
2666         if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2667                 goto out_writepages;
2668
2669         if (ext4_should_journal_data(inode)) {
2670                 ret = generic_writepages(mapping, wbc);
2671                 goto out_writepages;
2672         }
2673
2674         /*
2675          * If the filesystem has aborted, it is read-only, so return
2676          * right away instead of dumping stack traces later on that
2677          * will obscure the real source of the problem.  We test
2678          * EXT4_MF_FS_ABORTED instead of sb->s_flag's SB_RDONLY because
2679          * the latter could be true if the filesystem is mounted
2680          * read-only, and in that case, ext4_writepages should
2681          * *never* be called, so if that ever happens, we would want
2682          * the stack trace.
2683          */
2684         if (unlikely(ext4_forced_shutdown(EXT4_SB(mapping->host->i_sb)) ||
2685                      ext4_test_mount_flag(inode->i_sb, EXT4_MF_FS_ABORTED))) {
2686                 ret = -EROFS;
2687                 goto out_writepages;
2688         }
2689
2690         /*
2691          * If we have inline data and arrive here, it means that
2692          * we will soon create the block for the 1st page, so
2693          * we'd better clear the inline data here.
2694          */
2695         if (ext4_has_inline_data(inode)) {
2696                 /* Just inode will be modified... */
2697                 handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2698                 if (IS_ERR(handle)) {
2699                         ret = PTR_ERR(handle);
2700                         goto out_writepages;
2701                 }
2702                 BUG_ON(ext4_test_inode_state(inode,
2703                                 EXT4_STATE_MAY_INLINE_DATA));
2704                 ext4_destroy_inline_data(handle, inode);
2705                 ext4_journal_stop(handle);
2706         }
2707
2708         if (ext4_should_dioread_nolock(inode)) {
2709                 /*
2710                  * We may need to convert up to one extent per block in
2711                  * the page and we may dirty the inode.
2712                  */
2713                 rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
2714                                                 PAGE_SIZE >> inode->i_blkbits);
2715         }
2716
2717         if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2718                 range_whole = 1;
2719
2720         if (wbc->range_cyclic) {
2721                 writeback_index = mapping->writeback_index;
2722                 if (writeback_index)
2723                         cycled = 0;
2724                 mpd.first_page = writeback_index;
2725                 mpd.last_page = -1;
2726         } else {
2727                 mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2728                 mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2729         }
2730
2731         mpd.inode = inode;
2732         mpd.wbc = wbc;
2733         ext4_io_submit_init(&mpd.io_submit, wbc);
2734 retry:
2735         if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2736                 tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2737         blk_start_plug(&plug);
2738
2739         /*
2740          * First writeback pages that don't need mapping - we can avoid
2741          * starting a transaction unnecessarily and also avoid being blocked
2742          * in the block layer on device congestion while having transaction
2743          * started.
2744          */
2745         mpd.do_map = 0;
2746         mpd.scanned_until_end = 0;
2747         mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2748         if (!mpd.io_submit.io_end) {
2749                 ret = -ENOMEM;
2750                 goto unplug;
2751         }
2752         ret = mpage_prepare_extent_to_map(&mpd);
2753         /* Unlock pages we didn't use */
2754         mpage_release_unused_pages(&mpd, false);
2755         /* Submit prepared bio */
2756         ext4_io_submit(&mpd.io_submit);
2757         ext4_put_io_end_defer(mpd.io_submit.io_end);
2758         mpd.io_submit.io_end = NULL;
2759         if (ret < 0)
2760                 goto unplug;
2761
2762         while (!mpd.scanned_until_end && wbc->nr_to_write > 0) {
2763                 /* For each extent of pages we use new io_end */
2764                 mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2765                 if (!mpd.io_submit.io_end) {
2766                         ret = -ENOMEM;
2767                         break;
2768                 }
2769
2770                 /*
2771                  * We have two constraints: We find one extent to map and we
2772                  * must always write out whole page (makes a difference when
2773                  * blocksize < pagesize) so that we don't block on IO when we
2774                  * try to write out the rest of the page. Journalled mode is
2775                  * not supported by delalloc.
2776                  */
2777                 BUG_ON(ext4_should_journal_data(inode));
2778                 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2779
2780                 /* start a new transaction */
2781                 handle = ext4_journal_start_with_reserve(inode,
2782                                 EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2783                 if (IS_ERR(handle)) {
2784                         ret = PTR_ERR(handle);
2785                         ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2786                                "%ld pages, ino %lu; err %d", __func__,
2787                                 wbc->nr_to_write, inode->i_ino, ret);
2788                         /* Release allocated io_end */
2789                         ext4_put_io_end(mpd.io_submit.io_end);
2790                         mpd.io_submit.io_end = NULL;
2791                         break;
2792                 }
2793                 mpd.do_map = 1;
2794
2795                 trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2796                 ret = mpage_prepare_extent_to_map(&mpd);
2797                 if (!ret && mpd.map.m_len)
2798                         ret = mpage_map_and_submit_extent(handle, &mpd,
2799                                         &give_up_on_write);
2800                 /*
2801                  * Caution: If the handle is synchronous,
2802                  * ext4_journal_stop() can wait for transaction commit
2803                  * to finish which may depend on writeback of pages to
2804                  * complete or on page lock to be released.  In that
2805                  * case, we have to wait until after we have
2806                  * submitted all the IO, released page locks we hold,
2807                  * and dropped io_end reference (for extent conversion
2808                  * to be able to complete) before stopping the handle.
2809                  */
2810                 if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2811                         ext4_journal_stop(handle);
2812                         handle = NULL;
2813                         mpd.do_map = 0;
2814                 }
2815                 /* Unlock pages we didn't use */
2816                 mpage_release_unused_pages(&mpd, give_up_on_write);
2817                 /* Submit prepared bio */
2818                 ext4_io_submit(&mpd.io_submit);
2819
2820                 /*
2821                  * Drop our io_end reference we got from init. We have
2822                  * to be careful and use deferred io_end finishing if
2823                  * we are still holding the transaction as we can
2824                  * release the last reference to io_end which may end
2825                  * up doing unwritten extent conversion.
2826                  */
2827                 if (handle) {
2828                         ext4_put_io_end_defer(mpd.io_submit.io_end);
2829                         ext4_journal_stop(handle);
2830                 } else
2831                         ext4_put_io_end(mpd.io_submit.io_end);
2832                 mpd.io_submit.io_end = NULL;
2833
2834                 if (ret == -ENOSPC && sbi->s_journal) {
2835                         /*
2836                          * Commit the transaction which would
2837                          * free blocks released in the transaction
2838                          * and try again
2839                          */
2840                         jbd2_journal_force_commit_nested(sbi->s_journal);
2841                         ret = 0;
2842                         continue;
2843                 }
2844                 /* Fatal error - ENOMEM, EIO... */
2845                 if (ret)
2846                         break;
2847         }
2848 unplug:
2849         blk_finish_plug(&plug);
2850         if (!ret && !cycled && wbc->nr_to_write > 0) {
2851                 cycled = 1;
2852                 mpd.last_page = writeback_index - 1;
2853                 mpd.first_page = 0;
2854                 goto retry;
2855         }
2856
2857         /* Update index */
2858         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2859                 /*
2860                  * Set the writeback_index so that range_cyclic
2861                  * mode will write it back later
2862                  */
2863                 mapping->writeback_index = mpd.first_page;
2864
2865 out_writepages:
2866         trace_ext4_writepages_result(inode, wbc, ret,
2867                                      nr_to_write - wbc->nr_to_write);
2868         percpu_up_read(&sbi->s_writepages_rwsem);
2869         return ret;
2870 }
2871
2872 static int ext4_dax_writepages(struct address_space *mapping,
2873                                struct writeback_control *wbc)
2874 {
2875         int ret;
2876         long nr_to_write = wbc->nr_to_write;
2877         struct inode *inode = mapping->host;
2878         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2879
2880         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2881                 return -EIO;
2882
2883         percpu_down_read(&sbi->s_writepages_rwsem);
2884         trace_ext4_writepages(inode, wbc);
2885
2886         ret = dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
2887         trace_ext4_writepages_result(inode, wbc, ret,
2888                                      nr_to_write - wbc->nr_to_write);
2889         percpu_up_read(&sbi->s_writepages_rwsem);
2890         return ret;
2891 }
2892
2893 static int ext4_nonda_switch(struct super_block *sb)
2894 {
2895         s64 free_clusters, dirty_clusters;
2896         struct ext4_sb_info *sbi = EXT4_SB(sb);
2897
2898         /*
2899          * switch to non delalloc mode if we are running low
2900          * on free block. The free block accounting via percpu
2901          * counters can get slightly wrong with percpu_counter_batch getting
2902          * accumulated on each CPU without updating global counters
2903          * Delalloc need an accurate free block accounting. So switch
2904          * to non delalloc when we are near to error range.
2905          */
2906         free_clusters =
2907                 percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2908         dirty_clusters =
2909                 percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2910         /*
2911          * Start pushing delalloc when 1/2 of free blocks are dirty.
2912          */
2913         if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2914                 try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2915
2916         if (2 * free_clusters < 3 * dirty_clusters ||
2917             free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2918                 /*
2919                  * free block count is less than 150% of dirty blocks
2920                  * or free blocks is less than watermark
2921                  */
2922                 return 1;
2923         }
2924         return 0;
2925 }
2926
2927 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2928                                loff_t pos, unsigned len, unsigned flags,
2929                                struct page **pagep, void **fsdata)
2930 {
2931         int ret, retries = 0;
2932         struct page *page;
2933         pgoff_t index;
2934         struct inode *inode = mapping->host;
2935
2936         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2937                 return -EIO;
2938
2939         index = pos >> PAGE_SHIFT;
2940
2941         if (ext4_nonda_switch(inode->i_sb) || S_ISLNK(inode->i_mode) ||
2942             ext4_verity_in_progress(inode)) {
2943                 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2944                 return ext4_write_begin(file, mapping, pos,
2945                                         len, flags, pagep, fsdata);
2946         }
2947         *fsdata = (void *)0;
2948         trace_ext4_da_write_begin(inode, pos, len, flags);
2949
2950         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2951                 ret = ext4_da_write_inline_data_begin(mapping, inode,
2952                                                       pos, len, flags,
2953                                                       pagep, fsdata);
2954                 if (ret < 0)
2955                         return ret;
2956                 if (ret == 1)
2957                         return 0;
2958         }
2959
2960 retry:
2961         page = grab_cache_page_write_begin(mapping, index, flags);
2962         if (!page)
2963                 return -ENOMEM;
2964
2965         /* In case writeback began while the page was unlocked */
2966         wait_for_stable_page(page);
2967
2968 #ifdef CONFIG_FS_ENCRYPTION
2969         ret = ext4_block_write_begin(page, pos, len,
2970                                      ext4_da_get_block_prep);
2971 #else
2972         ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
2973 #endif
2974         if (ret < 0) {
2975                 unlock_page(page);
2976                 put_page(page);
2977                 /*
2978                  * block_write_begin may have instantiated a few blocks
2979                  * outside i_size.  Trim these off again. Don't need
2980                  * i_size_read because we hold inode lock.
2981                  */
2982                 if (pos + len > inode->i_size)
2983                         ext4_truncate_failed_write(inode);
2984
2985                 if (ret == -ENOSPC &&
2986                     ext4_should_retry_alloc(inode->i_sb, &retries))
2987                         goto retry;
2988                 return ret;
2989         }
2990
2991         *pagep = page;
2992         return ret;
2993 }
2994
2995 /*
2996  * Check if we should update i_disksize
2997  * when write to the end of file but not require block allocation
2998  */
2999 static int ext4_da_should_update_i_disksize(struct page *page,
3000                                             unsigned long offset)
3001 {
3002         struct buffer_head *bh;
3003         struct inode *inode = page->mapping->host;
3004         unsigned int idx;
3005         int i;
3006
3007         bh = page_buffers(page);
3008         idx = offset >> inode->i_blkbits;
3009
3010         for (i = 0; i < idx; i++)
3011                 bh = bh->b_this_page;
3012
3013         if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3014                 return 0;
3015         return 1;
3016 }
3017
3018 static int ext4_da_write_end(struct file *file,
3019                              struct address_space *mapping,
3020                              loff_t pos, unsigned len, unsigned copied,
3021                              struct page *page, void *fsdata)
3022 {
3023         struct inode *inode = mapping->host;
3024         loff_t new_i_size;
3025         unsigned long start, end;
3026         int write_mode = (int)(unsigned long)fsdata;
3027
3028         if (write_mode == FALL_BACK_TO_NONDELALLOC)
3029                 return ext4_write_end(file, mapping, pos,
3030                                       len, copied, page, fsdata);
3031
3032         trace_ext4_da_write_end(inode, pos, len, copied);
3033
3034         if (write_mode != CONVERT_INLINE_DATA &&
3035             ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3036             ext4_has_inline_data(inode))
3037                 return ext4_write_inline_data_end(inode, pos, len, copied, page);
3038
3039         start = pos & (PAGE_SIZE - 1);
3040         end = start + copied - 1;
3041
3042         /*
3043          * Since we are holding inode lock, we are sure i_disksize <=
3044          * i_size. We also know that if i_disksize < i_size, there are
3045          * delalloc writes pending in the range upto i_size. If the end of
3046          * the current write is <= i_size, there's no need to touch
3047          * i_disksize since writeback will push i_disksize upto i_size
3048          * eventually. If the end of the current write is > i_size and
3049          * inside an allocated block (ext4_da_should_update_i_disksize()
3050          * check), we need to update i_disksize here as neither
3051          * ext4_writepage() nor certain ext4_writepages() paths not
3052          * allocating blocks update i_disksize.
3053          *
3054          * Note that we defer inode dirtying to generic_write_end() /
3055          * ext4_da_write_inline_data_end().
3056          */
3057         new_i_size = pos + copied;
3058         if (copied && new_i_size > inode->i_size &&
3059             ext4_da_should_update_i_disksize(page, end))
3060                 ext4_update_i_disksize(inode, new_i_size);
3061
3062         return generic_write_end(file, mapping, pos, len, copied, page, fsdata);
3063 }
3064
3065 /*
3066  * Force all delayed allocation blocks to be allocated for a given inode.
3067  */
3068 int ext4_alloc_da_blocks(struct inode *inode)
3069 {
3070         trace_ext4_alloc_da_blocks(inode);
3071
3072         if (!EXT4_I(inode)->i_reserved_data_blocks)
3073                 return 0;
3074
3075         /*
3076          * We do something simple for now.  The filemap_flush() will
3077          * also start triggering a write of the data blocks, which is
3078          * not strictly speaking necessary (and for users of
3079          * laptop_mode, not even desirable).  However, to do otherwise
3080          * would require replicating code paths in:
3081          *
3082          * ext4_writepages() ->
3083          *    write_cache_pages() ---> (via passed in callback function)
3084          *        __mpage_da_writepage() -->
3085          *           mpage_add_bh_to_extent()
3086          *           mpage_da_map_blocks()
3087          *
3088          * The problem is that write_cache_pages(), located in
3089          * mm/page-writeback.c, marks pages clean in preparation for
3090          * doing I/O, which is not desirable if we're not planning on
3091          * doing I/O at all.
3092          *
3093          * We could call write_cache_pages(), and then redirty all of
3094          * the pages by calling redirty_page_for_writepage() but that
3095          * would be ugly in the extreme.  So instead we would need to
3096          * replicate parts of the code in the above functions,
3097          * simplifying them because we wouldn't actually intend to
3098          * write out the pages, but rather only collect contiguous
3099          * logical block extents, call the multi-block allocator, and
3100          * then update the buffer heads with the block allocations.
3101          *
3102          * For now, though, we'll cheat by calling filemap_flush(),
3103          * which will map the blocks, and start the I/O, but not
3104          * actually wait for the I/O to complete.
3105          */
3106         return filemap_flush(inode->i_mapping);
3107 }
3108
3109 /*
3110  * bmap() is special.  It gets used by applications such as lilo and by
3111  * the swapper to find the on-disk block of a specific piece of data.
3112  *
3113  * Naturally, this is dangerous if the block concerned is still in the
3114  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3115  * filesystem and enables swap, then they may get a nasty shock when the
3116  * data getting swapped to that swapfile suddenly gets overwritten by
3117  * the original zero's written out previously to the journal and
3118  * awaiting writeback in the kernel's buffer cache.
3119  *
3120  * So, if we see any bmap calls here on a modified, data-journaled file,
3121  * take extra steps to flush any blocks which might be in the cache.
3122  */
3123 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3124 {
3125         struct inode *inode = mapping->host;
3126         journal_t *journal;
3127         int err;
3128
3129         /*
3130          * We can get here for an inline file via the FIBMAP ioctl
3131          */
3132         if (ext4_has_inline_data(inode))
3133                 return 0;
3134
3135         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3136                         test_opt(inode->i_sb, DELALLOC)) {
3137                 /*
3138                  * With delalloc we want to sync the file
3139                  * so that we can make sure we allocate
3140                  * blocks for file
3141                  */
3142                 filemap_write_and_wait(mapping);
3143         }
3144
3145         if (EXT4_JOURNAL(inode) &&
3146             ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3147                 /*
3148                  * This is a REALLY heavyweight approach, but the use of
3149                  * bmap on dirty files is expected to be extremely rare:
3150                  * only if we run lilo or swapon on a freshly made file
3151                  * do we expect this to happen.
3152                  *
3153                  * (bmap requires CAP_SYS_RAWIO so this does not
3154                  * represent an unprivileged user DOS attack --- we'd be
3155                  * in trouble if mortal users could trigger this path at
3156                  * will.)
3157                  *
3158                  * NB. EXT4_STATE_JDATA is not set on files other than
3159                  * regular files.  If somebody wants to bmap a directory
3160                  * or symlink and gets confused because the buffer
3161                  * hasn't yet been flushed to disk, they deserve
3162                  * everything they get.
3163                  */
3164
3165                 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3166                 journal = EXT4_JOURNAL(inode);
3167                 jbd2_journal_lock_updates(journal);
3168                 err = jbd2_journal_flush(journal, 0);
3169                 jbd2_journal_unlock_updates(journal);
3170
3171                 if (err)
3172                         return 0;
3173         }
3174
3175         return iomap_bmap(mapping, block, &ext4_iomap_ops);
3176 }
3177
3178 static int ext4_readpage(struct file *file, struct page *page)
3179 {
3180         int ret = -EAGAIN;
3181         struct inode *inode = page->mapping->host;
3182
3183         trace_ext4_readpage(page);
3184
3185         if (ext4_has_inline_data(inode))
3186                 ret = ext4_readpage_inline(inode, page);
3187
3188         if (ret == -EAGAIN)
3189                 return ext4_mpage_readpages(inode, NULL, page);
3190
3191         return ret;
3192 }
3193
3194 static void ext4_readahead(struct readahead_control *rac)
3195 {
3196         struct inode *inode = rac->mapping->host;
3197
3198         /* If the file has inline data, no need to do readahead. */
3199         if (ext4_has_inline_data(inode))
3200                 return;
3201
3202         ext4_mpage_readpages(inode, rac, NULL);
3203 }
3204
3205 static void ext4_invalidatepage(struct page *page, unsigned int offset,
3206                                 unsigned int length)
3207 {
3208         trace_ext4_invalidatepage(page, offset, length);
3209
3210         /* No journalling happens on data buffers when this function is used */
3211         WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
3212
3213         block_invalidatepage(page, offset, length);
3214 }
3215
3216 static int __ext4_journalled_invalidatepage(struct page *page,
3217                                             unsigned int offset,
3218                                             unsigned int length)
3219 {
3220         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3221
3222         trace_ext4_journalled_invalidatepage(page, offset, length);
3223
3224         /*
3225          * If it's a full truncate we just forget about the pending dirtying
3226          */
3227         if (offset == 0 && length == PAGE_SIZE)
3228                 ClearPageChecked(page);
3229
3230         return jbd2_journal_invalidatepage(journal, page, offset, length);
3231 }
3232
3233 /* Wrapper for aops... */
3234 static void ext4_journalled_invalidatepage(struct page *page,
3235                                            unsigned int offset,
3236                                            unsigned int length)
3237 {
3238         WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3239 }
3240
3241 static int ext4_releasepage(struct page *page, gfp_t wait)
3242 {
3243         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3244
3245         trace_ext4_releasepage(page);
3246
3247         /* Page has dirty journalled data -> cannot release */
3248         if (PageChecked(page))
3249                 return 0;
3250         if (journal)
3251                 return jbd2_journal_try_to_free_buffers(journal, page);
3252         else
3253                 return try_to_free_buffers(page);
3254 }
3255
3256 static bool ext4_inode_datasync_dirty(struct inode *inode)
3257 {
3258         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3259
3260         if (journal) {
3261                 if (jbd2_transaction_committed(journal,
3262                         EXT4_I(inode)->i_datasync_tid))
3263                         return false;
3264                 if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
3265                         return !list_empty(&EXT4_I(inode)->i_fc_list);
3266                 return true;
3267         }
3268
3269         /* Any metadata buffers to write? */
3270         if (!list_empty(&inode->i_mapping->private_list))
3271                 return true;
3272         return inode->i_state & I_DIRTY_DATASYNC;
3273 }
3274
3275 static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
3276                            struct ext4_map_blocks *map, loff_t offset,
3277                            loff_t length)
3278 {
3279         u8 blkbits = inode->i_blkbits;
3280
3281         /*
3282          * Writes that span EOF might trigger an I/O size update on completion,
3283          * so consider them to be dirty for the purpose of O_DSYNC, even if
3284          * there is no other metadata changes being made or are pending.
3285          */
3286         iomap->flags = 0;
3287         if (ext4_inode_datasync_dirty(inode) ||
3288             offset + length > i_size_read(inode))
3289                 iomap->flags |= IOMAP_F_DIRTY;
3290
3291         if (map->m_flags & EXT4_MAP_NEW)
3292                 iomap->flags |= IOMAP_F_NEW;
3293
3294         iomap->bdev = inode->i_sb->s_bdev;
3295         iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
3296         iomap->offset = (u64) map->m_lblk << blkbits;
3297         iomap->length = (u64) map->m_len << blkbits;
3298
3299         if ((map->m_flags & EXT4_MAP_MAPPED) &&
3300             !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3301                 iomap->flags |= IOMAP_F_MERGED;
3302
3303         /*
3304          * Flags passed to ext4_map_blocks() for direct I/O writes can result
3305          * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3306          * set. In order for any allocated unwritten extents to be converted
3307          * into written extents correctly within the ->end_io() handler, we
3308          * need to ensure that the iomap->type is set appropriately. Hence, the
3309          * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3310          * been set first.
3311          */
3312         if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3313                 iomap->type = IOMAP_UNWRITTEN;
3314                 iomap->addr = (u64) map->m_pblk << blkbits;
3315         } else if (map->m_flags & EXT4_MAP_MAPPED) {
3316                 iomap->type = IOMAP_MAPPED;
3317                 iomap->addr = (u64) map->m_pblk << blkbits;
3318         } else {
3319                 iomap->type = IOMAP_HOLE;
3320                 iomap->addr = IOMAP_NULL_ADDR;
3321         }
3322 }
3323
3324 static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
3325                             unsigned int flags)
3326 {
3327         handle_t *handle;
3328         u8 blkbits = inode->i_blkbits;
3329         int ret, dio_credits, m_flags = 0, retries = 0;
3330
3331         /*
3332          * Trim the mapping request to the maximum value that we can map at
3333          * once for direct I/O.
3334          */
3335         if (map->m_len > DIO_MAX_BLOCKS)
3336                 map->m_len = DIO_MAX_BLOCKS;
3337         dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
3338
3339 retry:
3340         /*
3341          * Either we allocate blocks and then don't get an unwritten extent, so
3342          * in that case we have reserved enough credits. Or, the blocks are
3343          * already allocated and unwritten. In that case, the extent conversion
3344          * fits into the credits as well.
3345          */
3346         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3347         if (IS_ERR(handle))
3348                 return PTR_ERR(handle);
3349
3350         /*
3351          * DAX and direct I/O are the only two operations that are currently
3352          * supported with IOMAP_WRITE.
3353          */
3354         WARN_ON(!IS_DAX(inode) && !(flags & IOMAP_DIRECT));
3355         if (IS_DAX(inode))
3356                 m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3357         /*
3358          * We use i_size instead of i_disksize here because delalloc writeback
3359          * can complete at any point during the I/O and subsequently push the
3360          * i_disksize out to i_size. This could be beyond where direct I/O is
3361          * happening and thus expose allocated blocks to direct I/O reads.
3362          */
3363         else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
3364                 m_flags = EXT4_GET_BLOCKS_CREATE;
3365         else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3366                 m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3367
3368         ret = ext4_map_blocks(handle, inode, map, m_flags);
3369
3370         /*
3371          * We cannot fill holes in indirect tree based inodes as that could
3372          * expose stale data in the case of a crash. Use the magic error code
3373          * to fallback to buffered I/O.
3374          */
3375         if (!m_flags && !ret)
3376                 ret = -ENOTBLK;
3377
3378         ext4_journal_stop(handle);
3379         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3380                 goto retry;
3381
3382         return ret;
3383 }
3384
3385
3386 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3387                 unsigned flags, struct iomap *iomap, struct iomap *srcmap)
3388 {
3389         int ret;
3390         struct ext4_map_blocks map;
3391         u8 blkbits = inode->i_blkbits;
3392
3393         if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3394                 return -EINVAL;
3395
3396         if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3397                 return -ERANGE;
3398
3399         /*
3400          * Calculate the first and last logical blocks respectively.
3401          */
3402         map.m_lblk = offset >> blkbits;
3403         map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3404                           EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3405
3406         if (flags & IOMAP_WRITE) {
3407                 /*
3408                  * We check here if the blocks are already allocated, then we
3409                  * don't need to start a journal txn and we can directly return
3410                  * the mapping information. This could boost performance
3411                  * especially in multi-threaded overwrite requests.
3412                  */
3413                 if (offset + length <= i_size_read(inode)) {
3414                         ret = ext4_map_blocks(NULL, inode, &map, 0);
3415                         if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
3416                                 goto out;
3417                 }
3418                 ret = ext4_iomap_alloc(inode, &map, flags);
3419         } else {
3420                 ret = ext4_map_blocks(NULL, inode, &map, 0);
3421         }
3422
3423         if (ret < 0)
3424                 return ret;
3425 out:
3426         ext4_set_iomap(inode, iomap, &map, offset, length);
3427
3428         return 0;
3429 }
3430
3431 static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3432                 loff_t length, unsigned flags, struct iomap *iomap,
3433                 struct iomap *srcmap)
3434 {
3435         int ret;
3436
3437         /*
3438          * Even for writes we don't need to allocate blocks, so just pretend
3439          * we are reading to save overhead of starting a transaction.
3440          */
3441         flags &= ~IOMAP_WRITE;
3442         ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3443         WARN_ON_ONCE(iomap->type != IOMAP_MAPPED);
3444         return ret;
3445 }
3446
3447 static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3448                           ssize_t written, unsigned flags, struct iomap *iomap)
3449 {
3450         /*
3451          * Check to see whether an error occurred while writing out the data to
3452          * the allocated blocks. If so, return the magic error code so that we
3453          * fallback to buffered I/O and attempt to complete the remainder of
3454          * the I/O. Any blocks that may have been allocated in preparation for
3455          * the direct I/O will be reused during buffered I/O.
3456          */
3457         if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
3458                 return -ENOTBLK;
3459
3460         return 0;
3461 }
3462
3463 const struct iomap_ops ext4_iomap_ops = {
3464         .iomap_begin            = ext4_iomap_begin,
3465         .iomap_end              = ext4_iomap_end,
3466 };
3467
3468 const struct iomap_ops ext4_iomap_overwrite_ops = {
3469         .iomap_begin            = ext4_iomap_overwrite_begin,
3470         .iomap_end              = ext4_iomap_end,
3471 };
3472
3473 static bool ext4_iomap_is_delalloc(struct inode *inode,
3474                                    struct ext4_map_blocks *map)
3475 {
3476         struct extent_status es;
3477         ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1;
3478
3479         ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
3480                                   map->m_lblk, end, &es);
3481
3482         if (!es.es_len || es.es_lblk > end)
3483                 return false;
3484
3485         if (es.es_lblk > map->m_lblk) {
3486                 map->m_len = es.es_lblk - map->m_lblk;
3487                 return false;
3488         }
3489
3490         offset = map->m_lblk - es.es_lblk;
3491         map->m_len = es.es_len - offset;
3492
3493         return true;
3494 }
3495
3496 static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3497                                    loff_t length, unsigned int flags,
3498                                    struct iomap *iomap, struct iomap *srcmap)
3499 {
3500         int ret;
3501         bool delalloc = false;
3502         struct ext4_map_blocks map;
3503         u8 blkbits = inode->i_blkbits;
3504
3505         if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3506                 return -EINVAL;
3507
3508         if (ext4_has_inline_data(inode)) {
3509                 ret = ext4_inline_data_iomap(inode, iomap);
3510                 if (ret != -EAGAIN) {
3511                         if (ret == 0 && offset >= iomap->length)
3512                                 ret = -ENOENT;
3513                         return ret;
3514                 }
3515         }
3516
3517         /*
3518          * Calculate the first and last logical block respectively.
3519          */
3520         map.m_lblk = offset >> blkbits;
3521         map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3522                           EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3523
3524         /*
3525          * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3526          * So handle it here itself instead of querying ext4_map_blocks().
3527          * Since ext4_map_blocks() will warn about it and will return
3528          * -EIO error.
3529          */
3530         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3531                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3532
3533                 if (offset >= sbi->s_bitmap_maxbytes) {
3534                         map.m_flags = 0;
3535                         goto set_iomap;
3536                 }
3537         }
3538
3539         ret = ext4_map_blocks(NULL, inode, &map, 0);
3540         if (ret < 0)
3541                 return ret;
3542         if (ret == 0)
3543                 delalloc = ext4_iomap_is_delalloc(inode, &map);
3544
3545 set_iomap:
3546         ext4_set_iomap(inode, iomap, &map, offset, length);
3547         if (delalloc && iomap->type == IOMAP_HOLE)
3548                 iomap->type = IOMAP_DELALLOC;
3549
3550         return 0;
3551 }
3552
3553 const struct iomap_ops ext4_iomap_report_ops = {
3554         .iomap_begin = ext4_iomap_begin_report,
3555 };
3556
3557 /*
3558  * Pages can be marked dirty completely asynchronously from ext4's journalling
3559  * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3560  * much here because ->set_page_dirty is called under VFS locks.  The page is
3561  * not necessarily locked.
3562  *
3563  * We cannot just dirty the page and leave attached buffers clean, because the
3564  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3565  * or jbddirty because all the journalling code will explode.
3566  *
3567  * So what we do is to mark the page "pending dirty" and next time writepage
3568  * is called, propagate that into the buffers appropriately.
3569  */
3570 static int ext4_journalled_set_page_dirty(struct page *page)
3571 {
3572         SetPageChecked(page);
3573         return __set_page_dirty_nobuffers(page);
3574 }
3575
3576 static int ext4_set_page_dirty(struct page *page)
3577 {
3578         WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page));
3579         WARN_ON_ONCE(!page_has_buffers(page));
3580         return __set_page_dirty_buffers(page);
3581 }
3582
3583 static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
3584                                     struct file *file, sector_t *span)
3585 {
3586         return iomap_swapfile_activate(sis, file, span,
3587                                        &ext4_iomap_report_ops);
3588 }
3589
3590 static const struct address_space_operations ext4_aops = {
3591         .readpage               = ext4_readpage,
3592         .readahead              = ext4_readahead,
3593         .writepage              = ext4_writepage,
3594         .writepages             = ext4_writepages,
3595         .write_begin            = ext4_write_begin,
3596         .write_end              = ext4_write_end,
3597         .set_page_dirty         = ext4_set_page_dirty,
3598         .bmap                   = ext4_bmap,
3599         .invalidatepage         = ext4_invalidatepage,
3600         .releasepage            = ext4_releasepage,
3601         .direct_IO              = noop_direct_IO,
3602         .migratepage            = buffer_migrate_page,
3603         .is_partially_uptodate  = block_is_partially_uptodate,
3604         .error_remove_page      = generic_error_remove_page,
3605         .swap_activate          = ext4_iomap_swap_activate,
3606 };
3607
3608 static const struct address_space_operations ext4_journalled_aops = {
3609         .readpage               = ext4_readpage,
3610         .readahead              = ext4_readahead,
3611         .writepage              = ext4_writepage,
3612         .writepages             = ext4_writepages,
3613         .write_begin            = ext4_write_begin,
3614         .write_end              = ext4_journalled_write_end,
3615         .set_page_dirty         = ext4_journalled_set_page_dirty,
3616         .bmap                   = ext4_bmap,
3617         .invalidatepage         = ext4_journalled_invalidatepage,
3618         .releasepage            = ext4_releasepage,
3619         .direct_IO              = noop_direct_IO,
3620         .is_partially_uptodate  = block_is_partially_uptodate,
3621         .error_remove_page      = generic_error_remove_page,
3622         .swap_activate          = ext4_iomap_swap_activate,
3623 };
3624
3625 static const struct address_space_operations ext4_da_aops = {
3626         .readpage               = ext4_readpage,
3627         .readahead              = ext4_readahead,
3628         .writepage              = ext4_writepage,
3629         .writepages             = ext4_writepages,
3630         .write_begin            = ext4_da_write_begin,
3631         .write_end              = ext4_da_write_end,
3632         .set_page_dirty         = ext4_set_page_dirty,
3633         .bmap                   = ext4_bmap,
3634         .invalidatepage         = ext4_invalidatepage,
3635         .releasepage            = ext4_releasepage,
3636         .direct_IO              = noop_direct_IO,
3637         .migratepage            = buffer_migrate_page,
3638         .is_partially_uptodate  = block_is_partially_uptodate,
3639         .error_remove_page      = generic_error_remove_page,
3640         .swap_activate          = ext4_iomap_swap_activate,
3641 };
3642
3643 static const struct address_space_operations ext4_dax_aops = {
3644         .writepages             = ext4_dax_writepages,
3645         .direct_IO              = noop_direct_IO,
3646         .set_page_dirty         = __set_page_dirty_no_writeback,
3647         .bmap                   = ext4_bmap,
3648         .invalidatepage         = noop_invalidatepage,
3649         .swap_activate          = ext4_iomap_swap_activate,
3650 };
3651
3652 void ext4_set_aops(struct inode *inode)
3653 {
3654         switch (ext4_inode_journal_mode(inode)) {
3655         case EXT4_INODE_ORDERED_DATA_MODE:
3656         case EXT4_INODE_WRITEBACK_DATA_MODE:
3657                 break;
3658         case EXT4_INODE_JOURNAL_DATA_MODE:
3659                 inode->i_mapping->a_ops = &ext4_journalled_aops;
3660                 return;
3661         default:
3662                 BUG();
3663         }
3664         if (IS_DAX(inode))
3665                 inode->i_mapping->a_ops = &ext4_dax_aops;
3666         else if (test_opt(inode->i_sb, DELALLOC))
3667                 inode->i_mapping->a_ops = &ext4_da_aops;
3668         else
3669                 inode->i_mapping->a_ops = &ext4_aops;
3670 }
3671
3672 static int __ext4_block_zero_page_range(handle_t *handle,
3673                 struct address_space *mapping, loff_t from, loff_t length)
3674 {
3675         ext4_fsblk_t index = from >> PAGE_SHIFT;
3676         unsigned offset = from & (PAGE_SIZE-1);
3677         unsigned blocksize, pos;
3678         ext4_lblk_t iblock;
3679         struct inode *inode = mapping->host;
3680         struct buffer_head *bh;
3681         struct page *page;
3682         int err = 0;
3683
3684         page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3685                                    mapping_gfp_constraint(mapping, ~__GFP_FS));
3686         if (!page)
3687                 return -ENOMEM;
3688
3689         blocksize = inode->i_sb->s_blocksize;
3690
3691         iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3692
3693         if (!page_has_buffers(page))
3694                 create_empty_buffers(page, blocksize, 0);
3695
3696         /* Find the buffer that contains "offset" */
3697         bh = page_buffers(page);
3698         pos = blocksize;
3699         while (offset >= pos) {
3700                 bh = bh->b_this_page;
3701                 iblock++;
3702                 pos += blocksize;
3703         }
3704         if (buffer_freed(bh)) {
3705                 BUFFER_TRACE(bh, "freed: skip");
3706                 goto unlock;
3707         }
3708         if (!buffer_mapped(bh)) {
3709                 BUFFER_TRACE(bh, "unmapped");
3710                 ext4_get_block(inode, iblock, bh, 0);
3711                 /* unmapped? It's a hole - nothing to do */
3712                 if (!buffer_mapped(bh)) {
3713                         BUFFER_TRACE(bh, "still unmapped");
3714                         goto unlock;
3715                 }
3716         }
3717
3718         /* Ok, it's mapped. Make sure it's up-to-date */
3719         if (PageUptodate(page))
3720                 set_buffer_uptodate(bh);
3721
3722         if (!buffer_uptodate(bh)) {
3723                 err = ext4_read_bh_lock(bh, 0, true);
3724                 if (err)
3725                         goto unlock;
3726                 if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
3727                         /* We expect the key to be set. */
3728                         BUG_ON(!fscrypt_has_encryption_key(inode));
3729                         err = fscrypt_decrypt_pagecache_blocks(page, blocksize,
3730                                                                bh_offset(bh));
3731                         if (err) {
3732                                 clear_buffer_uptodate(bh);
3733                                 goto unlock;
3734                         }
3735                 }
3736         }
3737         if (ext4_should_journal_data(inode)) {
3738                 BUFFER_TRACE(bh, "get write access");
3739                 err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
3740                                                     EXT4_JTR_NONE);
3741                 if (err)
3742                         goto unlock;
3743         }
3744         zero_user(page, offset, length);
3745         BUFFER_TRACE(bh, "zeroed end of block");
3746
3747         if (ext4_should_journal_data(inode)) {
3748                 err = ext4_handle_dirty_metadata(handle, inode, bh);
3749         } else {
3750                 err = 0;
3751                 mark_buffer_dirty(bh);
3752                 if (ext4_should_order_data(inode))
3753                         err = ext4_jbd2_inode_add_write(handle, inode, from,
3754                                         length);
3755         }
3756
3757 unlock:
3758         unlock_page(page);
3759         put_page(page);
3760         return err;
3761 }
3762
3763 /*
3764  * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3765  * starting from file offset 'from'.  The range to be zero'd must
3766  * be contained with in one block.  If the specified range exceeds
3767  * the end of the block it will be shortened to end of the block
3768  * that corresponds to 'from'
3769  */
3770 static int ext4_block_zero_page_range(handle_t *handle,
3771                 struct address_space *mapping, loff_t from, loff_t length)
3772 {
3773         struct inode *inode = mapping->host;
3774         unsigned offset = from & (PAGE_SIZE-1);
3775         unsigned blocksize = inode->i_sb->s_blocksize;
3776         unsigned max = blocksize - (offset & (blocksize - 1));
3777
3778         /*
3779          * correct length if it does not fall between
3780          * 'from' and the end of the block
3781          */
3782         if (length > max || length < 0)
3783                 length = max;
3784
3785         if (IS_DAX(inode)) {
3786                 return iomap_zero_range(inode, from, length, NULL,
3787                                         &ext4_iomap_ops);
3788         }
3789         return __ext4_block_zero_page_range(handle, mapping, from, length);
3790 }
3791
3792 /*
3793  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3794  * up to the end of the block which corresponds to `from'.
3795  * This required during truncate. We need to physically zero the tail end
3796  * of that block so it doesn't yield old data if the file is later grown.
3797  */
3798 static int ext4_block_truncate_page(handle_t *handle,
3799                 struct address_space *mapping, loff_t from)
3800 {
3801         unsigned offset = from & (PAGE_SIZE-1);
3802         unsigned length;
3803         unsigned blocksize;
3804         struct inode *inode = mapping->host;
3805
3806         /* If we are processing an encrypted inode during orphan list handling */
3807         if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
3808                 return 0;
3809
3810         blocksize = inode->i_sb->s_blocksize;
3811         length = blocksize - (offset & (blocksize - 1));
3812
3813         return ext4_block_zero_page_range(handle, mapping, from, length);
3814 }
3815
3816 int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3817                              loff_t lstart, loff_t length)
3818 {
3819         struct super_block *sb = inode->i_sb;
3820         struct address_space *mapping = inode->i_mapping;
3821         unsigned partial_start, partial_end;
3822         ext4_fsblk_t start, end;
3823         loff_t byte_end = (lstart + length - 1);
3824         int err = 0;
3825
3826         partial_start = lstart & (sb->s_blocksize - 1);
3827         partial_end = byte_end & (sb->s_blocksize - 1);
3828
3829         start = lstart >> sb->s_blocksize_bits;
3830         end = byte_end >> sb->s_blocksize_bits;
3831
3832         /* Handle partial zero within the single block */
3833         if (start == end &&
3834             (partial_start || (partial_end != sb->s_blocksize - 1))) {
3835                 err = ext4_block_zero_page_range(handle, mapping,
3836                                                  lstart, length);
3837                 return err;
3838         }
3839         /* Handle partial zero out on the start of the range */
3840         if (partial_start) {
3841                 err = ext4_block_zero_page_range(handle, mapping,
3842                                                  lstart, sb->s_blocksize);
3843                 if (err)
3844                         return err;
3845         }
3846         /* Handle partial zero out on the end of the range */
3847         if (partial_end != sb->s_blocksize - 1)
3848                 err = ext4_block_zero_page_range(handle, mapping,
3849                                                  byte_end - partial_end,
3850                                                  partial_end + 1);
3851         return err;
3852 }
3853
3854 int ext4_can_truncate(struct inode *inode)
3855 {
3856         if (S_ISREG(inode->i_mode))
3857                 return 1;
3858         if (S_ISDIR(inode->i_mode))
3859                 return 1;
3860         if (S_ISLNK(inode->i_mode))
3861                 return !ext4_inode_is_fast_symlink(inode);
3862         return 0;
3863 }
3864
3865 /*
3866  * We have to make sure i_disksize gets properly updated before we truncate
3867  * page cache due to hole punching or zero range. Otherwise i_disksize update
3868  * can get lost as it may have been postponed to submission of writeback but
3869  * that will never happen after we truncate page cache.
3870  */
3871 int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3872                                       loff_t len)
3873 {
3874         handle_t *handle;
3875         int ret;
3876
3877         loff_t size = i_size_read(inode);
3878
3879         WARN_ON(!inode_is_locked(inode));
3880         if (offset > size || offset + len < size)
3881                 return 0;
3882
3883         if (EXT4_I(inode)->i_disksize >= size)
3884                 return 0;
3885
3886         handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3887         if (IS_ERR(handle))
3888                 return PTR_ERR(handle);
3889         ext4_update_i_disksize(inode, size);
3890         ret = ext4_mark_inode_dirty(handle, inode);
3891         ext4_journal_stop(handle);
3892
3893         return ret;
3894 }
3895
3896 static void ext4_wait_dax_page(struct inode *inode)
3897 {
3898         filemap_invalidate_unlock(inode->i_mapping);
3899         schedule();
3900         filemap_invalidate_lock(inode->i_mapping);
3901 }
3902
3903 int ext4_break_layouts(struct inode *inode)
3904 {
3905         struct page *page;
3906         int error;
3907
3908         if (WARN_ON_ONCE(!rwsem_is_locked(&inode->i_mapping->invalidate_lock)))
3909                 return -EINVAL;
3910
3911         do {
3912                 page = dax_layout_busy_page(inode->i_mapping);
3913                 if (!page)
3914                         return 0;
3915
3916                 error = ___wait_var_event(&page->_refcount,
3917                                 atomic_read(&page->_refcount) == 1,
3918                                 TASK_INTERRUPTIBLE, 0, 0,
3919                                 ext4_wait_dax_page(inode));
3920         } while (error == 0);
3921
3922         return error;
3923 }
3924
3925 /*
3926  * ext4_punch_hole: punches a hole in a file by releasing the blocks
3927  * associated with the given offset and length
3928  *
3929  * @inode:  File inode
3930  * @offset: The offset where the hole will begin
3931  * @len:    The length of the hole
3932  *
3933  * Returns: 0 on success or negative on failure
3934  */
3935
3936 int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
3937 {
3938         struct super_block *sb = inode->i_sb;
3939         ext4_lblk_t first_block, stop_block;
3940         struct address_space *mapping = inode->i_mapping;
3941         loff_t first_block_offset, last_block_offset;
3942         handle_t *handle;
3943         unsigned int credits;
3944         int ret = 0, ret2 = 0;
3945
3946         trace_ext4_punch_hole(inode, offset, length, 0);
3947
3948         ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
3949         if (ext4_has_inline_data(inode)) {
3950                 filemap_invalidate_lock(mapping);
3951                 ret = ext4_convert_inline_data(inode);
3952                 filemap_invalidate_unlock(mapping);
3953                 if (ret)
3954                         return ret;
3955         }
3956
3957         /*
3958          * Write out all dirty pages to avoid race conditions
3959          * Then release them.
3960          */
3961         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
3962                 ret = filemap_write_and_wait_range(mapping, offset,
3963                                                    offset + length - 1);
3964                 if (ret)
3965                         return ret;
3966         }
3967
3968         inode_lock(inode);
3969
3970         /* No need to punch hole beyond i_size */
3971         if (offset >= inode->i_size)
3972                 goto out_mutex;
3973
3974         /*
3975          * If the hole extends beyond i_size, set the hole
3976          * to end after the page that contains i_size
3977          */
3978         if (offset + length > inode->i_size) {
3979                 length = inode->i_size +
3980                    PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
3981                    offset;
3982         }
3983
3984         if (offset & (sb->s_blocksize - 1) ||
3985             (offset + length) & (sb->s_blocksize - 1)) {
3986                 /*
3987                  * Attach jinode to inode for jbd2 if we do any zeroing of
3988                  * partial block
3989                  */
3990                 ret = ext4_inode_attach_jinode(inode);
3991                 if (ret < 0)
3992                         goto out_mutex;
3993
3994         }
3995
3996         /* Wait all existing dio workers, newcomers will block on i_mutex */
3997         inode_dio_wait(inode);
3998
3999         /*
4000          * Prevent page faults from reinstantiating pages we have released from
4001          * page cache.
4002          */
4003         filemap_invalidate_lock(mapping);
4004
4005         ret = ext4_break_layouts(inode);
4006         if (ret)
4007                 goto out_dio;
4008
4009         first_block_offset = round_up(offset, sb->s_blocksize);
4010         last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
4011
4012         /* Now release the pages and zero block aligned part of pages*/
4013         if (last_block_offset > first_block_offset) {
4014                 ret = ext4_update_disksize_before_punch(inode, offset, length);
4015                 if (ret)
4016                         goto out_dio;
4017                 truncate_pagecache_range(inode, first_block_offset,
4018                                          last_block_offset);
4019         }
4020
4021         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4022                 credits = ext4_writepage_trans_blocks(inode);
4023         else
4024                 credits = ext4_blocks_for_truncate(inode);
4025         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4026         if (IS_ERR(handle)) {
4027                 ret = PTR_ERR(handle);
4028                 ext4_std_error(sb, ret);
4029                 goto out_dio;
4030         }
4031
4032         ret = ext4_zero_partial_blocks(handle, inode, offset,
4033                                        length);
4034         if (ret)
4035                 goto out_stop;
4036
4037         first_block = (offset + sb->s_blocksize - 1) >>
4038                 EXT4_BLOCK_SIZE_BITS(sb);
4039         stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4040
4041         /* If there are blocks to remove, do it */
4042         if (stop_block > first_block) {
4043
4044                 down_write(&EXT4_I(inode)->i_data_sem);
4045                 ext4_discard_preallocations(inode, 0);
4046
4047                 ret = ext4_es_remove_extent(inode, first_block,
4048                                             stop_block - first_block);
4049                 if (ret) {
4050                         up_write(&EXT4_I(inode)->i_data_sem);
4051                         goto out_stop;
4052                 }
4053
4054                 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4055                         ret = ext4_ext_remove_space(inode, first_block,
4056                                                     stop_block - 1);
4057                 else
4058                         ret = ext4_ind_remove_space(handle, inode, first_block,
4059                                                     stop_block);
4060
4061                 up_write(&EXT4_I(inode)->i_data_sem);
4062         }
4063         ext4_fc_track_range(handle, inode, first_block, stop_block);
4064         if (IS_SYNC(inode))
4065                 ext4_handle_sync(handle);
4066
4067         inode->i_mtime = inode->i_ctime = current_time(inode);
4068         ret2 = ext4_mark_inode_dirty(handle, inode);
4069         if (unlikely(ret2))
4070                 ret = ret2;
4071         if (ret >= 0)
4072                 ext4_update_inode_fsync_trans(handle, inode, 1);
4073 out_stop:
4074         ext4_journal_stop(handle);
4075 out_dio:
4076         filemap_invalidate_unlock(mapping);
4077 out_mutex:
4078         inode_unlock(inode);
4079         return ret;
4080 }
4081
4082 int ext4_inode_attach_jinode(struct inode *inode)
4083 {
4084         struct ext4_inode_info *ei = EXT4_I(inode);
4085         struct jbd2_inode *jinode;
4086
4087         if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4088                 return 0;
4089
4090         jinode = jbd2_alloc_inode(GFP_KERNEL);
4091         spin_lock(&inode->i_lock);
4092         if (!ei->jinode) {
4093                 if (!jinode) {
4094                         spin_unlock(&inode->i_lock);
4095                         return -ENOMEM;
4096                 }
4097                 ei->jinode = jinode;
4098                 jbd2_journal_init_jbd_inode(ei->jinode, inode);
4099                 jinode = NULL;
4100         }
4101         spin_unlock(&inode->i_lock);
4102         if (unlikely(jinode != NULL))
4103                 jbd2_free_inode(jinode);
4104         return 0;
4105 }
4106
4107 /*
4108  * ext4_truncate()
4109  *
4110  * We block out ext4_get_block() block instantiations across the entire
4111  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4112  * simultaneously on behalf of the same inode.
4113  *
4114  * As we work through the truncate and commit bits of it to the journal there
4115  * is one core, guiding principle: the file's tree must always be consistent on
4116  * disk.  We must be able to restart the truncate after a crash.
4117  *
4118  * The file's tree may be transiently inconsistent in memory (although it
4119  * probably isn't), but whenever we close off and commit a journal transaction,
4120  * the contents of (the filesystem + the journal) must be consistent and
4121  * restartable.  It's pretty simple, really: bottom up, right to left (although
4122  * left-to-right works OK too).
4123  *
4124  * Note that at recovery time, journal replay occurs *before* the restart of
4125  * truncate against the orphan inode list.
4126  *
4127  * The committed inode has the new, desired i_size (which is the same as
4128  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4129  * that this inode's truncate did not complete and it will again call
4130  * ext4_truncate() to have another go.  So there will be instantiated blocks
4131  * to the right of the truncation point in a crashed ext4 filesystem.  But
4132  * that's fine - as long as they are linked from the inode, the post-crash
4133  * ext4_truncate() run will find them and release them.
4134  */
4135 int ext4_truncate(struct inode *inode)
4136 {
4137         struct ext4_inode_info *ei = EXT4_I(inode);
4138         unsigned int credits;
4139         int err = 0, err2;
4140         handle_t *handle;
4141         struct address_space *mapping = inode->i_mapping;
4142
4143         /*
4144          * There is a possibility that we're either freeing the inode
4145          * or it's a completely new inode. In those cases we might not
4146          * have i_mutex locked because it's not necessary.
4147          */
4148         if (!(inode->i_state & (I_NEW|I_FREEING)))
4149                 WARN_ON(!inode_is_locked(inode));
4150         trace_ext4_truncate_enter(inode);
4151
4152         if (!ext4_can_truncate(inode))
4153                 goto out_trace;
4154
4155         if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4156                 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4157
4158         if (ext4_has_inline_data(inode)) {
4159                 int has_inline = 1;
4160
4161                 err = ext4_inline_data_truncate(inode, &has_inline);
4162                 if (err || has_inline)
4163                         goto out_trace;
4164         }
4165
4166         /* If we zero-out tail of the page, we have to create jinode for jbd2 */
4167         if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4168                 if (ext4_inode_attach_jinode(inode) < 0)
4169                         goto out_trace;
4170         }
4171
4172         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4173                 credits = ext4_writepage_trans_blocks(inode);
4174         else
4175                 credits = ext4_blocks_for_truncate(inode);
4176
4177         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4178         if (IS_ERR(handle)) {
4179                 err = PTR_ERR(handle);
4180                 goto out_trace;
4181         }
4182
4183         if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4184                 ext4_block_truncate_page(handle, mapping, inode->i_size);
4185
4186         /*
4187          * We add the inode to the orphan list, so that if this
4188          * truncate spans multiple transactions, and we crash, we will
4189          * resume the truncate when the filesystem recovers.  It also
4190          * marks the inode dirty, to catch the new size.
4191          *
4192          * Implication: the file must always be in a sane, consistent
4193          * truncatable state while each transaction commits.
4194          */
4195         err = ext4_orphan_add(handle, inode);
4196         if (err)
4197                 goto out_stop;
4198
4199         down_write(&EXT4_I(inode)->i_data_sem);
4200
4201         ext4_discard_preallocations(inode, 0);
4202
4203         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4204                 err = ext4_ext_truncate(handle, inode);
4205         else
4206                 ext4_ind_truncate(handle, inode);
4207
4208         up_write(&ei->i_data_sem);
4209         if (err)
4210                 goto out_stop;
4211
4212         if (IS_SYNC(inode))
4213                 ext4_handle_sync(handle);
4214
4215 out_stop:
4216         /*
4217          * If this was a simple ftruncate() and the file will remain alive,
4218          * then we need to clear up the orphan record which we created above.
4219          * However, if this was a real unlink then we were called by
4220          * ext4_evict_inode(), and we allow that function to clean up the
4221          * orphan info for us.
4222          */
4223         if (inode->i_nlink)
4224                 ext4_orphan_del(handle, inode);
4225
4226         inode->i_mtime = inode->i_ctime = current_time(inode);
4227         err2 = ext4_mark_inode_dirty(handle, inode);
4228         if (unlikely(err2 && !err))
4229                 err = err2;
4230         ext4_journal_stop(handle);
4231
4232 out_trace:
4233         trace_ext4_truncate_exit(inode);
4234         return err;
4235 }
4236
4237 /*
4238  * ext4_get_inode_loc returns with an extra refcount against the inode's
4239  * underlying buffer_head on success. If 'in_mem' is true, we have all
4240  * data in memory that is needed to recreate the on-disk version of this
4241  * inode.
4242  */
4243 static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
4244                                 struct ext4_iloc *iloc, int in_mem,
4245                                 ext4_fsblk_t *ret_block)
4246 {
4247         struct ext4_group_desc  *gdp;
4248         struct buffer_head      *bh;
4249         ext4_fsblk_t            block;
4250         struct blk_plug         plug;
4251         int                     inodes_per_block, inode_offset;
4252
4253         iloc->bh = NULL;
4254         if (ino < EXT4_ROOT_INO ||
4255             ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4256                 return -EFSCORRUPTED;
4257
4258         iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
4259         gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4260         if (!gdp)
4261                 return -EIO;
4262
4263         /*
4264          * Figure out the offset within the block group inode table
4265          */
4266         inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4267         inode_offset = ((ino - 1) %
4268                         EXT4_INODES_PER_GROUP(sb));
4269         block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4270         iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4271
4272         bh = sb_getblk(sb, block);
4273         if (unlikely(!bh))
4274                 return -ENOMEM;
4275         if (ext4_buffer_uptodate(bh))
4276                 goto has_buffer;
4277
4278         lock_buffer(bh);
4279         if (ext4_buffer_uptodate(bh)) {
4280                 /* Someone brought it uptodate while we waited */
4281                 unlock_buffer(bh);
4282                 goto has_buffer;
4283         }
4284
4285         /*
4286          * If we have all information of the inode in memory and this
4287          * is the only valid inode in the block, we need not read the
4288          * block.
4289          */
4290         if (in_mem) {
4291                 struct buffer_head *bitmap_bh;
4292                 int i, start;
4293
4294                 start = inode_offset & ~(inodes_per_block - 1);
4295
4296                 /* Is the inode bitmap in cache? */
4297                 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4298                 if (unlikely(!bitmap_bh))
4299                         goto make_io;
4300
4301                 /*
4302                  * If the inode bitmap isn't in cache then the
4303                  * optimisation may end up performing two reads instead
4304                  * of one, so skip it.
4305                  */
4306                 if (!buffer_uptodate(bitmap_bh)) {
4307                         brelse(bitmap_bh);
4308                         goto make_io;
4309                 }
4310                 for (i = start; i < start + inodes_per_block; i++) {
4311                         if (i == inode_offset)
4312                                 continue;
4313                         if (ext4_test_bit(i, bitmap_bh->b_data))
4314                                 break;
4315                 }
4316                 brelse(bitmap_bh);
4317                 if (i == start + inodes_per_block) {
4318                         /* all other inodes are free, so skip I/O */
4319                         memset(bh->b_data, 0, bh->b_size);
4320                         set_buffer_uptodate(bh);
4321                         unlock_buffer(bh);
4322                         goto has_buffer;
4323                 }
4324         }
4325
4326 make_io:
4327         /*
4328          * If we need to do any I/O, try to pre-readahead extra
4329          * blocks from the inode table.
4330          */
4331         blk_start_plug(&plug);
4332         if (EXT4_SB(sb)->s_inode_readahead_blks) {
4333                 ext4_fsblk_t b, end, table;
4334                 unsigned num;
4335                 __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4336
4337                 table = ext4_inode_table(sb, gdp);
4338                 /* s_inode_readahead_blks is always a power of 2 */
4339                 b = block & ~((ext4_fsblk_t) ra_blks - 1);
4340                 if (table > b)
4341                         b = table;
4342                 end = b + ra_blks;
4343                 num = EXT4_INODES_PER_GROUP(sb);
4344                 if (ext4_has_group_desc_csum(sb))
4345                         num -= ext4_itable_unused_count(sb, gdp);
4346                 table += num / inodes_per_block;
4347                 if (end > table)
4348                         end = table;
4349                 while (b <= end)
4350                         ext4_sb_breadahead_unmovable(sb, b++);
4351         }
4352
4353         /*
4354          * There are other valid inodes in the buffer, this inode
4355          * has in-inode xattrs, or we don't have this inode in memory.
4356          * Read the block from disk.
4357          */
4358         trace_ext4_load_inode(sb, ino);
4359         ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
4360         blk_finish_plug(&plug);
4361         wait_on_buffer(bh);
4362         ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
4363         if (!buffer_uptodate(bh)) {
4364                 if (ret_block)
4365                         *ret_block = block;
4366                 brelse(bh);
4367                 return -EIO;
4368         }
4369 has_buffer:
4370         iloc->bh = bh;
4371         return 0;
4372 }
4373
4374 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
4375                                         struct ext4_iloc *iloc)
4376 {
4377         ext4_fsblk_t err_blk;
4378         int ret;
4379
4380         ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, 0,
4381                                         &err_blk);
4382
4383         if (ret == -EIO)
4384                 ext4_error_inode_block(inode, err_blk, EIO,
4385                                         "unable to read itable block");
4386
4387         return ret;
4388 }
4389
4390 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4391 {
4392         ext4_fsblk_t err_blk;
4393         int ret;
4394
4395         /* We have all inode data except xattrs in memory here. */
4396         ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc,
4397                 !ext4_test_inode_state(inode, EXT4_STATE_XATTR), &err_blk);
4398
4399         if (ret == -EIO)
4400                 ext4_error_inode_block(inode, err_blk, EIO,
4401                                         "unable to read itable block");
4402
4403         return ret;
4404 }
4405
4406
4407 int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
4408                           struct ext4_iloc *iloc)
4409 {
4410         return __ext4_get_inode_loc(sb, ino, iloc, 0, NULL);
4411 }
4412
4413 static bool ext4_should_enable_dax(struct inode *inode)
4414 {
4415         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4416
4417         if (test_opt2(inode->i_sb, DAX_NEVER))
4418                 return false;
4419         if (!S_ISREG(inode->i_mode))
4420                 return false;
4421         if (ext4_should_journal_data(inode))
4422                 return false;
4423         if (ext4_has_inline_data(inode))
4424                 return false;
4425         if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
4426                 return false;
4427         if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
4428                 return false;
4429         if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4430                 return false;
4431         if (test_opt(inode->i_sb, DAX_ALWAYS))
4432                 return true;
4433
4434         return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
4435 }
4436
4437 void ext4_set_inode_flags(struct inode *inode, bool init)
4438 {
4439         unsigned int flags = EXT4_I(inode)->i_flags;
4440         unsigned int new_fl = 0;
4441
4442         WARN_ON_ONCE(IS_DAX(inode) && init);
4443
4444         if (flags & EXT4_SYNC_FL)
4445                 new_fl |= S_SYNC;
4446         if (flags & EXT4_APPEND_FL)
4447                 new_fl |= S_APPEND;
4448         if (flags & EXT4_IMMUTABLE_FL)
4449                 new_fl |= S_IMMUTABLE;
4450         if (flags & EXT4_NOATIME_FL)
4451                 new_fl |= S_NOATIME;
4452         if (flags & EXT4_DIRSYNC_FL)
4453                 new_fl |= S_DIRSYNC;
4454
4455         /* Because of the way inode_set_flags() works we must preserve S_DAX
4456          * here if already set. */
4457         new_fl |= (inode->i_flags & S_DAX);
4458         if (init && ext4_should_enable_dax(inode))
4459                 new_fl |= S_DAX;
4460
4461         if (flags & EXT4_ENCRYPT_FL)
4462                 new_fl |= S_ENCRYPTED;
4463         if (flags & EXT4_CASEFOLD_FL)
4464                 new_fl |= S_CASEFOLD;
4465         if (flags & EXT4_VERITY_FL)
4466                 new_fl |= S_VERITY;
4467         inode_set_flags(inode, new_fl,
4468                         S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4469                         S_ENCRYPTED|S_CASEFOLD|S_VERITY);
4470 }
4471
4472 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4473                                   struct ext4_inode_info *ei)
4474 {
4475         blkcnt_t i_blocks ;
4476         struct inode *inode = &(ei->vfs_inode);
4477         struct super_block *sb = inode->i_sb;
4478
4479         if (ext4_has_feature_huge_file(sb)) {
4480                 /* we are using combined 48 bit field */
4481                 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4482                                         le32_to_cpu(raw_inode->i_blocks_lo);
4483                 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4484                         /* i_blocks represent file system block size */
4485                         return i_blocks  << (inode->i_blkbits - 9);
4486                 } else {
4487                         return i_blocks;
4488                 }
4489         } else {
4490                 return le32_to_cpu(raw_inode->i_blocks_lo);
4491         }
4492 }
4493
4494 static inline int ext4_iget_extra_inode(struct inode *inode,
4495                                          struct ext4_inode *raw_inode,
4496                                          struct ext4_inode_info *ei)
4497 {
4498         __le32 *magic = (void *)raw_inode +
4499                         EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4500
4501         if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize + sizeof(__le32) <=
4502             EXT4_INODE_SIZE(inode->i_sb) &&
4503             *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4504                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4505                 return ext4_find_inline_data_nolock(inode);
4506         } else
4507                 EXT4_I(inode)->i_inline_off = 0;
4508         return 0;
4509 }
4510
4511 int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4512 {
4513         if (!ext4_has_feature_project(inode->i_sb))
4514                 return -EOPNOTSUPP;
4515         *projid = EXT4_I(inode)->i_projid;
4516         return 0;
4517 }
4518
4519 /*
4520  * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
4521  * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
4522  * set.
4523  */
4524 static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
4525 {
4526         if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4527                 inode_set_iversion_raw(inode, val);
4528         else
4529                 inode_set_iversion_queried(inode, val);
4530 }
4531 static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4532 {
4533         if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4534                 return inode_peek_iversion_raw(inode);
4535         else
4536                 return inode_peek_iversion(inode);
4537 }
4538
4539 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
4540                           ext4_iget_flags flags, const char *function,
4541                           unsigned int line)
4542 {
4543         struct ext4_iloc iloc;
4544         struct ext4_inode *raw_inode;
4545         struct ext4_inode_info *ei;
4546         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4547         struct inode *inode;
4548         journal_t *journal = EXT4_SB(sb)->s_journal;
4549         long ret;
4550         loff_t size;
4551         int block;
4552         uid_t i_uid;
4553         gid_t i_gid;
4554         projid_t i_projid;
4555
4556         if ((!(flags & EXT4_IGET_SPECIAL) &&
4557              ((ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO) ||
4558               ino == le32_to_cpu(es->s_usr_quota_inum) ||
4559               ino == le32_to_cpu(es->s_grp_quota_inum) ||
4560               ino == le32_to_cpu(es->s_prj_quota_inum) ||
4561               ino == le32_to_cpu(es->s_orphan_file_inum))) ||
4562             (ino < EXT4_ROOT_INO) ||
4563             (ino > le32_to_cpu(es->s_inodes_count))) {
4564                 if (flags & EXT4_IGET_HANDLE)
4565                         return ERR_PTR(-ESTALE);
4566                 __ext4_error(sb, function, line, false, EFSCORRUPTED, 0,
4567                              "inode #%lu: comm %s: iget: illegal inode #",
4568                              ino, current->comm);
4569                 return ERR_PTR(-EFSCORRUPTED);
4570         }
4571
4572         inode = iget_locked(sb, ino);
4573         if (!inode)
4574                 return ERR_PTR(-ENOMEM);
4575         if (!(inode->i_state & I_NEW))
4576                 return inode;
4577
4578         ei = EXT4_I(inode);
4579         iloc.bh = NULL;
4580
4581         ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
4582         if (ret < 0)
4583                 goto bad_inode;
4584         raw_inode = ext4_raw_inode(&iloc);
4585
4586         if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) {
4587                 ext4_error_inode(inode, function, line, 0,
4588                                  "iget: root inode unallocated");
4589                 ret = -EFSCORRUPTED;
4590                 goto bad_inode;
4591         }
4592
4593         if ((flags & EXT4_IGET_HANDLE) &&
4594             (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
4595                 ret = -ESTALE;
4596                 goto bad_inode;
4597         }
4598
4599         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4600                 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4601                 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4602                         EXT4_INODE_SIZE(inode->i_sb) ||
4603                     (ei->i_extra_isize & 3)) {
4604                         ext4_error_inode(inode, function, line, 0,
4605                                          "iget: bad extra_isize %u "
4606                                          "(inode size %u)",
4607                                          ei->i_extra_isize,
4608                                          EXT4_INODE_SIZE(inode->i_sb));
4609                         ret = -EFSCORRUPTED;
4610                         goto bad_inode;
4611                 }
4612         } else
4613                 ei->i_extra_isize = 0;
4614
4615         /* Precompute checksum seed for inode metadata */
4616         if (ext4_has_metadata_csum(sb)) {
4617                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4618                 __u32 csum;
4619                 __le32 inum = cpu_to_le32(inode->i_ino);
4620                 __le32 gen = raw_inode->i_generation;
4621                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4622                                    sizeof(inum));
4623                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4624                                               sizeof(gen));
4625         }
4626
4627         if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
4628             ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
4629              (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
4630                 ext4_error_inode_err(inode, function, line, 0,
4631                                 EFSBADCRC, "iget: checksum invalid");
4632                 ret = -EFSBADCRC;
4633                 goto bad_inode;
4634         }
4635
4636         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4637         i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4638         i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4639         if (ext4_has_feature_project(sb) &&
4640             EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4641             EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4642                 i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4643         else
4644                 i_projid = EXT4_DEF_PROJID;
4645
4646         if (!(test_opt(inode->i_sb, NO_UID32))) {
4647                 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4648                 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4649         }
4650         i_uid_write(inode, i_uid);
4651         i_gid_write(inode, i_gid);
4652         ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4653         set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4654
4655         ext4_clear_state_flags(ei);     /* Only relevant on 32-bit archs */
4656         ei->i_inline_off = 0;
4657         ei->i_dir_start_lookup = 0;
4658         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4659         /* We now have enough fields to check if the inode was active or not.
4660          * This is needed because nfsd might try to access dead inodes
4661          * the test is that same one that e2fsck uses
4662          * NeilBrown 1999oct15
4663          */
4664         if (inode->i_nlink == 0) {
4665                 if ((inode->i_mode == 0 ||
4666                      !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4667                     ino != EXT4_BOOT_LOADER_INO) {
4668                         /* this inode is deleted */
4669                         ret = -ESTALE;
4670                         goto bad_inode;
4671                 }
4672                 /* The only unlinked inodes we let through here have
4673                  * valid i_mode and are being read by the orphan
4674                  * recovery code: that's fine, we're about to complete
4675                  * the process of deleting those.
4676                  * OR it is the EXT4_BOOT_LOADER_INO which is
4677                  * not initialized on a new filesystem. */
4678         }
4679         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4680         ext4_set_inode_flags(inode, true);
4681         inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4682         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4683         if (ext4_has_feature_64bit(sb))
4684                 ei->i_file_acl |=
4685                         ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4686         inode->i_size = ext4_isize(sb, raw_inode);
4687         if ((size = i_size_read(inode)) < 0) {
4688                 ext4_error_inode(inode, function, line, 0,
4689                                  "iget: bad i_size value: %lld", size);
4690                 ret = -EFSCORRUPTED;
4691                 goto bad_inode;
4692         }
4693         /*
4694          * If dir_index is not enabled but there's dir with INDEX flag set,
4695          * we'd normally treat htree data as empty space. But with metadata
4696          * checksumming that corrupts checksums so forbid that.
4697          */
4698         if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
4699             ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
4700                 ext4_error_inode(inode, function, line, 0,
4701                          "iget: Dir with htree data on filesystem without dir_index feature.");
4702                 ret = -EFSCORRUPTED;
4703                 goto bad_inode;
4704         }
4705         ei->i_disksize = inode->i_size;
4706 #ifdef CONFIG_QUOTA
4707         ei->i_reserved_quota = 0;
4708 #endif
4709         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4710         ei->i_block_group = iloc.block_group;
4711         ei->i_last_alloc_group = ~0;
4712         /*
4713          * NOTE! The in-memory inode i_data array is in little-endian order
4714          * even on big-endian machines: we do NOT byteswap the block numbers!
4715          */
4716         for (block = 0; block < EXT4_N_BLOCKS; block++)
4717                 ei->i_data[block] = raw_inode->i_block[block];
4718         INIT_LIST_HEAD(&ei->i_orphan);
4719         ext4_fc_init_inode(&ei->vfs_inode);
4720
4721         /*
4722          * Set transaction id's of transactions that have to be committed
4723          * to finish f[data]sync. We set them to currently running transaction
4724          * as we cannot be sure that the inode or some of its metadata isn't
4725          * part of the transaction - the inode could have been reclaimed and
4726          * now it is reread from disk.
4727          */
4728         if (journal) {
4729                 transaction_t *transaction;
4730                 tid_t tid;
4731
4732                 read_lock(&journal->j_state_lock);
4733                 if (journal->j_running_transaction)
4734                         transaction = journal->j_running_transaction;
4735                 else
4736                         transaction = journal->j_committing_transaction;
4737                 if (transaction)
4738                         tid = transaction->t_tid;
4739                 else
4740                         tid = journal->j_commit_sequence;
4741                 read_unlock(&journal->j_state_lock);
4742                 ei->i_sync_tid = tid;
4743                 ei->i_datasync_tid = tid;
4744         }
4745
4746         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4747                 if (ei->i_extra_isize == 0) {
4748                         /* The extra space is currently unused. Use it. */
4749                         BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4750                         ei->i_extra_isize = sizeof(struct ext4_inode) -
4751                                             EXT4_GOOD_OLD_INODE_SIZE;
4752                 } else {
4753                         ret = ext4_iget_extra_inode(inode, raw_inode, ei);
4754                         if (ret)
4755                                 goto bad_inode;
4756                 }
4757         }
4758
4759         EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4760         EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4761         EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4762         EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4763
4764         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4765                 u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4766
4767                 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4768                         if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4769                                 ivers |=
4770                     (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4771                 }
4772                 ext4_inode_set_iversion_queried(inode, ivers);
4773         }
4774
4775         ret = 0;
4776         if (ei->i_file_acl &&
4777             !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
4778                 ext4_error_inode(inode, function, line, 0,
4779                                  "iget: bad extended attribute block %llu",
4780                                  ei->i_file_acl);
4781                 ret = -EFSCORRUPTED;
4782                 goto bad_inode;
4783         } else if (!ext4_has_inline_data(inode)) {
4784                 /* validate the block references in the inode */
4785                 if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
4786                         (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4787                         (S_ISLNK(inode->i_mode) &&
4788                         !ext4_inode_is_fast_symlink(inode)))) {
4789                         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4790                                 ret = ext4_ext_check_inode(inode);
4791                         else
4792                                 ret = ext4_ind_check_inode(inode);
4793                 }
4794         }
4795         if (ret)
4796                 goto bad_inode;
4797
4798         if (S_ISREG(inode->i_mode)) {
4799                 inode->i_op = &ext4_file_inode_operations;
4800                 inode->i_fop = &ext4_file_operations;
4801                 ext4_set_aops(inode);
4802         } else if (S_ISDIR(inode->i_mode)) {
4803                 inode->i_op = &ext4_dir_inode_operations;
4804                 inode->i_fop = &ext4_dir_operations;
4805         } else if (S_ISLNK(inode->i_mode)) {
4806                 /* VFS does not allow setting these so must be corruption */
4807                 if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
4808                         ext4_error_inode(inode, function, line, 0,
4809                                          "iget: immutable or append flags "
4810                                          "not allowed on symlinks");
4811                         ret = -EFSCORRUPTED;
4812                         goto bad_inode;
4813                 }
4814                 if (IS_ENCRYPTED(inode)) {
4815                         inode->i_op = &ext4_encrypted_symlink_inode_operations;
4816                         ext4_set_aops(inode);
4817                 } else if (ext4_inode_is_fast_symlink(inode)) {
4818                         inode->i_link = (char *)ei->i_data;
4819                         inode->i_op = &ext4_fast_symlink_inode_operations;
4820                         nd_terminate_link(ei->i_data, inode->i_size,
4821                                 sizeof(ei->i_data) - 1);
4822                 } else {
4823                         inode->i_op = &ext4_symlink_inode_operations;
4824                         ext4_set_aops(inode);
4825                 }
4826                 inode_nohighmem(inode);
4827         } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4828               S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4829                 inode->i_op = &ext4_special_inode_operations;
4830                 if (raw_inode->i_block[0])
4831                         init_special_inode(inode, inode->i_mode,
4832                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4833                 else
4834                         init_special_inode(inode, inode->i_mode,
4835                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4836         } else if (ino == EXT4_BOOT_LOADER_INO) {
4837                 make_bad_inode(inode);
4838         } else {
4839                 ret = -EFSCORRUPTED;
4840                 ext4_error_inode(inode, function, line, 0,
4841                                  "iget: bogus i_mode (%o)", inode->i_mode);
4842                 goto bad_inode;
4843         }
4844         if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb))
4845                 ext4_error_inode(inode, function, line, 0,
4846                                  "casefold flag without casefold feature");
4847         brelse(iloc.bh);
4848
4849         unlock_new_inode(inode);
4850         return inode;
4851
4852 bad_inode:
4853         brelse(iloc.bh);
4854         iget_failed(inode);
4855         return ERR_PTR(ret);
4856 }
4857
4858 static int ext4_inode_blocks_set(handle_t *handle,
4859                                 struct ext4_inode *raw_inode,
4860                                 struct ext4_inode_info *ei)
4861 {
4862         struct inode *inode = &(ei->vfs_inode);
4863         u64 i_blocks = READ_ONCE(inode->i_blocks);
4864         struct super_block *sb = inode->i_sb;
4865
4866         if (i_blocks <= ~0U) {
4867                 /*
4868                  * i_blocks can be represented in a 32 bit variable
4869                  * as multiple of 512 bytes
4870                  */
4871                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4872                 raw_inode->i_blocks_high = 0;
4873                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4874                 return 0;
4875         }
4876
4877         /*
4878          * This should never happen since sb->s_maxbytes should not have
4879          * allowed this, sb->s_maxbytes was set according to the huge_file
4880          * feature in ext4_fill_super().
4881          */
4882         if (!ext4_has_feature_huge_file(sb))
4883                 return -EFSCORRUPTED;
4884
4885         if (i_blocks <= 0xffffffffffffULL) {
4886                 /*
4887                  * i_blocks can be represented in a 48 bit variable
4888                  * as multiple of 512 bytes
4889                  */
4890                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4891                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4892                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4893         } else {
4894                 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4895                 /* i_block is stored in file system block size */
4896                 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4897                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4898                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4899         }
4900         return 0;
4901 }
4902
4903 static void __ext4_update_other_inode_time(struct super_block *sb,
4904                                            unsigned long orig_ino,
4905                                            unsigned long ino,
4906                                            struct ext4_inode *raw_inode)
4907 {
4908         struct inode *inode;
4909
4910         inode = find_inode_by_ino_rcu(sb, ino);
4911         if (!inode)
4912                 return;
4913
4914         if (!inode_is_dirtytime_only(inode))
4915                 return;
4916
4917         spin_lock(&inode->i_lock);
4918         if (inode_is_dirtytime_only(inode)) {
4919                 struct ext4_inode_info  *ei = EXT4_I(inode);
4920
4921                 inode->i_state &= ~I_DIRTY_TIME;
4922                 spin_unlock(&inode->i_lock);
4923
4924                 spin_lock(&ei->i_raw_lock);
4925                 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4926                 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4927                 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4928                 ext4_inode_csum_set(inode, raw_inode, ei);
4929                 spin_unlock(&ei->i_raw_lock);
4930                 trace_ext4_other_inode_update_time(inode, orig_ino);
4931                 return;
4932         }
4933         spin_unlock(&inode->i_lock);
4934 }
4935
4936 /*
4937  * Opportunistically update the other time fields for other inodes in
4938  * the same inode table block.
4939  */
4940 static void ext4_update_other_inodes_time(struct super_block *sb,
4941                                           unsigned long orig_ino, char *buf)
4942 {
4943         unsigned long ino;
4944         int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4945         int inode_size = EXT4_INODE_SIZE(sb);
4946
4947         /*
4948          * Calculate the first inode in the inode table block.  Inode
4949          * numbers are one-based.  That is, the first inode in a block
4950          * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
4951          */
4952         ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
4953         rcu_read_lock();
4954         for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
4955                 if (ino == orig_ino)
4956                         continue;
4957                 __ext4_update_other_inode_time(sb, orig_ino, ino,
4958                                                (struct ext4_inode *)buf);
4959         }
4960         rcu_read_unlock();
4961 }
4962
4963 /*
4964  * Post the struct inode info into an on-disk inode location in the
4965  * buffer-cache.  This gobbles the caller's reference to the
4966  * buffer_head in the inode location struct.
4967  *
4968  * The caller must have write access to iloc->bh.
4969  */
4970 static int ext4_do_update_inode(handle_t *handle,
4971                                 struct inode *inode,
4972                                 struct ext4_iloc *iloc)
4973 {
4974         struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4975         struct ext4_inode_info *ei = EXT4_I(inode);
4976         struct buffer_head *bh = iloc->bh;
4977         struct super_block *sb = inode->i_sb;
4978         int err = 0, block;
4979         int need_datasync = 0, set_large_file = 0;
4980         uid_t i_uid;
4981         gid_t i_gid;
4982         projid_t i_projid;
4983
4984         spin_lock(&ei->i_raw_lock);
4985
4986         /*
4987          * For fields not tracked in the in-memory inode, initialise them
4988          * to zero for new inodes.
4989          */
4990         if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
4991                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4992
4993         err = ext4_inode_blocks_set(handle, raw_inode, ei);
4994
4995         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4996         i_uid = i_uid_read(inode);
4997         i_gid = i_gid_read(inode);
4998         i_projid = from_kprojid(&init_user_ns, ei->i_projid);
4999         if (!(test_opt(inode->i_sb, NO_UID32))) {
5000                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
5001                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
5002                 /*
5003                  * Fix up interoperability with old kernels. Otherwise,
5004                  * old inodes get re-used with the upper 16 bits of the
5005                  * uid/gid intact.
5006                  */
5007                 if (ei->i_dtime && list_empty(&ei->i_orphan)) {
5008                         raw_inode->i_uid_high = 0;
5009                         raw_inode->i_gid_high = 0;
5010                 } else {
5011                         raw_inode->i_uid_high =
5012                                 cpu_to_le16(high_16_bits(i_uid));
5013                         raw_inode->i_gid_high =
5014                                 cpu_to_le16(high_16_bits(i_gid));
5015                 }
5016         } else {
5017                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
5018                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
5019                 raw_inode->i_uid_high = 0;
5020                 raw_inode->i_gid_high = 0;
5021         }
5022         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5023
5024         EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5025         EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5026         EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5027         EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5028
5029         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5030         raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
5031         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
5032                 raw_inode->i_file_acl_high =
5033                         cpu_to_le16(ei->i_file_acl >> 32);
5034         raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5035         if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode)) {
5036                 ext4_isize_set(raw_inode, ei->i_disksize);
5037                 need_datasync = 1;
5038         }
5039         if (ei->i_disksize > 0x7fffffffULL) {
5040                 if (!ext4_has_feature_large_file(sb) ||
5041                                 EXT4_SB(sb)->s_es->s_rev_level ==
5042                     cpu_to_le32(EXT4_GOOD_OLD_REV))
5043                         set_large_file = 1;
5044         }
5045         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5046         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5047                 if (old_valid_dev(inode->i_rdev)) {
5048                         raw_inode->i_block[0] =
5049                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
5050                         raw_inode->i_block[1] = 0;
5051                 } else {
5052                         raw_inode->i_block[0] = 0;
5053                         raw_inode->i_block[1] =
5054                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
5055                         raw_inode->i_block[2] = 0;
5056                 }
5057         } else if (!ext4_has_inline_data(inode)) {
5058                 for (block = 0; block < EXT4_N_BLOCKS; block++)
5059                         raw_inode->i_block[block] = ei->i_data[block];
5060         }
5061
5062         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
5063                 u64 ivers = ext4_inode_peek_iversion(inode);
5064
5065                 raw_inode->i_disk_version = cpu_to_le32(ivers);
5066                 if (ei->i_extra_isize) {
5067                         if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5068                                 raw_inode->i_version_hi =
5069                                         cpu_to_le32(ivers >> 32);
5070                         raw_inode->i_extra_isize =
5071                                 cpu_to_le16(ei->i_extra_isize);
5072                 }
5073         }
5074
5075         if (i_projid != EXT4_DEF_PROJID &&
5076             !ext4_has_feature_project(inode->i_sb))
5077                 err = err ?: -EFSCORRUPTED;
5078
5079         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
5080             EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
5081                 raw_inode->i_projid = cpu_to_le32(i_projid);
5082
5083         ext4_inode_csum_set(inode, raw_inode, ei);
5084         spin_unlock(&ei->i_raw_lock);
5085         if (err) {
5086                 EXT4_ERROR_INODE(inode, "corrupted inode contents");
5087                 goto out_brelse;
5088         }
5089
5090         if (inode->i_sb->s_flags & SB_LAZYTIME)
5091                 ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5092                                               bh->b_data);
5093
5094         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5095         err = ext4_handle_dirty_metadata(handle, NULL, bh);
5096         if (err)
5097                 goto out_error;
5098         ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5099         if (set_large_file) {
5100                 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5101                 err = ext4_journal_get_write_access(handle, sb,
5102                                                     EXT4_SB(sb)->s_sbh,
5103                                                     EXT4_JTR_NONE);
5104                 if (err)
5105                         goto out_error;
5106                 lock_buffer(EXT4_SB(sb)->s_sbh);
5107                 ext4_set_feature_large_file(sb);
5108                 ext4_superblock_csum_set(sb);
5109                 unlock_buffer(EXT4_SB(sb)->s_sbh);
5110                 ext4_handle_sync(handle);
5111                 err = ext4_handle_dirty_metadata(handle, NULL,
5112                                                  EXT4_SB(sb)->s_sbh);
5113         }
5114         ext4_update_inode_fsync_trans(handle, inode, need_datasync);
5115 out_error:
5116         ext4_std_error(inode->i_sb, err);
5117 out_brelse:
5118         brelse(bh);
5119         return err;
5120 }
5121
5122 /*
5123  * ext4_write_inode()
5124  *
5125  * We are called from a few places:
5126  *
5127  * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5128  *   Here, there will be no transaction running. We wait for any running
5129  *   transaction to commit.
5130  *
5131  * - Within flush work (sys_sync(), kupdate and such).
5132  *   We wait on commit, if told to.
5133  *
5134  * - Within iput_final() -> write_inode_now()
5135  *   We wait on commit, if told to.
5136  *
5137  * In all cases it is actually safe for us to return without doing anything,
5138  * because the inode has been copied into a raw inode buffer in
5139  * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5140  * writeback.
5141  *
5142  * Note that we are absolutely dependent upon all inode dirtiers doing the
5143  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5144  * which we are interested.
5145  *
5146  * It would be a bug for them to not do this.  The code:
5147  *
5148  *      mark_inode_dirty(inode)
5149  *      stuff();
5150  *      inode->i_size = expr;
5151  *
5152  * is in error because write_inode() could occur while `stuff()' is running,
5153  * and the new i_size will be lost.  Plus the inode will no longer be on the
5154  * superblock's dirty inode list.
5155  */
5156 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5157 {
5158         int err;
5159
5160         if (WARN_ON_ONCE(current->flags & PF_MEMALLOC) ||
5161             sb_rdonly(inode->i_sb))
5162                 return 0;
5163
5164         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5165                 return -EIO;
5166
5167         if (EXT4_SB(inode->i_sb)->s_journal) {
5168                 if (ext4_journal_current_handle()) {
5169                         jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5170                         dump_stack();
5171                         return -EIO;
5172                 }
5173
5174                 /*
5175                  * No need to force transaction in WB_SYNC_NONE mode. Also
5176                  * ext4_sync_fs() will force the commit after everything is
5177                  * written.
5178                  */
5179                 if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5180                         return 0;
5181
5182                 err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
5183                                                 EXT4_I(inode)->i_sync_tid);
5184         } else {
5185                 struct ext4_iloc iloc;
5186
5187                 err = __ext4_get_inode_loc_noinmem(inode, &iloc);
5188                 if (err)
5189                         return err;
5190                 /*
5191                  * sync(2) will flush the whole buffer cache. No need to do
5192                  * it here separately for each inode.
5193                  */
5194                 if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5195                         sync_dirty_buffer(iloc.bh);
5196                 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5197                         ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5198                                                "IO error syncing inode");
5199                         err = -EIO;
5200                 }
5201                 brelse(iloc.bh);
5202         }
5203         return err;
5204 }
5205
5206 /*
5207  * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
5208  * buffers that are attached to a page stradding i_size and are undergoing
5209  * commit. In that case we have to wait for commit to finish and try again.
5210  */
5211 static void ext4_wait_for_tail_page_commit(struct inode *inode)
5212 {
5213         struct page *page;
5214         unsigned offset;
5215         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5216         tid_t commit_tid = 0;
5217         int ret;
5218
5219         offset = inode->i_size & (PAGE_SIZE - 1);
5220         /*
5221          * If the page is fully truncated, we don't need to wait for any commit
5222          * (and we even should not as __ext4_journalled_invalidatepage() may
5223          * strip all buffers from the page but keep the page dirty which can then
5224          * confuse e.g. concurrent ext4_writepage() seeing dirty page without
5225          * buffers). Also we don't need to wait for any commit if all buffers in
5226          * the page remain valid. This is most beneficial for the common case of
5227          * blocksize == PAGESIZE.
5228          */
5229         if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
5230                 return;
5231         while (1) {
5232                 page = find_lock_page(inode->i_mapping,
5233                                       inode->i_size >> PAGE_SHIFT);
5234                 if (!page)
5235                         return;
5236                 ret = __ext4_journalled_invalidatepage(page, offset,
5237                                                 PAGE_SIZE - offset);
5238                 unlock_page(page);
5239                 put_page(page);
5240                 if (ret != -EBUSY)
5241                         return;
5242                 commit_tid = 0;
5243                 read_lock(&journal->j_state_lock);
5244                 if (journal->j_committing_transaction)
5245                         commit_tid = journal->j_committing_transaction->t_tid;
5246                 read_unlock(&journal->j_state_lock);
5247                 if (commit_tid)
5248                         jbd2_log_wait_commit(journal, commit_tid);
5249         }
5250 }
5251
5252 /*
5253  * ext4_setattr()
5254  *
5255  * Called from notify_change.
5256  *
5257  * We want to trap VFS attempts to truncate the file as soon as
5258  * possible.  In particular, we want to make sure that when the VFS
5259  * shrinks i_size, we put the inode on the orphan list and modify
5260  * i_disksize immediately, so that during the subsequent flushing of
5261  * dirty pages and freeing of disk blocks, we can guarantee that any
5262  * commit will leave the blocks being flushed in an unused state on
5263  * disk.  (On recovery, the inode will get truncated and the blocks will
5264  * be freed, so we have a strong guarantee that no future commit will
5265  * leave these blocks visible to the user.)
5266  *
5267  * Another thing we have to assure is that if we are in ordered mode
5268  * and inode is still attached to the committing transaction, we must
5269  * we start writeout of all the dirty pages which are being truncated.
5270  * This way we are sure that all the data written in the previous
5271  * transaction are already on disk (truncate waits for pages under
5272  * writeback).
5273  *
5274  * Called with inode->i_mutex down.
5275  */
5276 int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
5277                  struct iattr *attr)
5278 {
5279         struct inode *inode = d_inode(dentry);
5280         int error, rc = 0;
5281         int orphan = 0;
5282         const unsigned int ia_valid = attr->ia_valid;
5283
5284         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5285                 return -EIO;
5286
5287         if (unlikely(IS_IMMUTABLE(inode)))
5288                 return -EPERM;
5289
5290         if (unlikely(IS_APPEND(inode) &&
5291                      (ia_valid & (ATTR_MODE | ATTR_UID |
5292                                   ATTR_GID | ATTR_TIMES_SET))))
5293                 return -EPERM;
5294
5295         error = setattr_prepare(mnt_userns, dentry, attr);
5296         if (error)
5297                 return error;
5298
5299         error = fscrypt_prepare_setattr(dentry, attr);
5300         if (error)
5301                 return error;
5302
5303         error = fsverity_prepare_setattr(dentry, attr);
5304         if (error)
5305                 return error;
5306
5307         if (is_quota_modification(inode, attr)) {
5308                 error = dquot_initialize(inode);
5309                 if (error)
5310                         return error;
5311         }
5312         ext4_fc_start_update(inode);
5313         if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
5314             (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
5315                 handle_t *handle;
5316
5317                 /* (user+group)*(old+new) structure, inode write (sb,
5318                  * inode block, ? - but truncate inode update has it) */
5319                 handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5320                         (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5321                          EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5322                 if (IS_ERR(handle)) {
5323                         error = PTR_ERR(handle);
5324                         goto err_out;
5325                 }
5326
5327                 /* dquot_transfer() calls back ext4_get_inode_usage() which
5328                  * counts xattr inode references.
5329                  */
5330                 down_read(&EXT4_I(inode)->xattr_sem);
5331                 error = dquot_transfer(inode, attr);
5332                 up_read(&EXT4_I(inode)->xattr_sem);
5333
5334                 if (error) {
5335                         ext4_journal_stop(handle);
5336                         ext4_fc_stop_update(inode);
5337                         return error;
5338                 }
5339                 /* Update corresponding info in inode so that everything is in
5340                  * one transaction */
5341                 if (attr->ia_valid & ATTR_UID)
5342                         inode->i_uid = attr->ia_uid;
5343                 if (attr->ia_valid & ATTR_GID)
5344                         inode->i_gid = attr->ia_gid;
5345                 error = ext4_mark_inode_dirty(handle, inode);
5346                 ext4_journal_stop(handle);
5347                 if (unlikely(error)) {
5348                         ext4_fc_stop_update(inode);
5349                         return error;
5350                 }
5351         }
5352
5353         if (attr->ia_valid & ATTR_SIZE) {
5354                 handle_t *handle;
5355                 loff_t oldsize = inode->i_size;
5356                 int shrink = (attr->ia_size < inode->i_size);
5357
5358                 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5359                         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5360
5361                         if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5362                                 ext4_fc_stop_update(inode);
5363                                 return -EFBIG;
5364                         }
5365                 }
5366                 if (!S_ISREG(inode->i_mode)) {
5367                         ext4_fc_stop_update(inode);
5368                         return -EINVAL;
5369                 }
5370
5371                 if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5372                         inode_inc_iversion(inode);
5373
5374                 if (shrink) {
5375                         if (ext4_should_order_data(inode)) {
5376                                 error = ext4_begin_ordered_truncate(inode,
5377                                                             attr->ia_size);
5378                                 if (error)
5379                                         goto err_out;
5380                         }
5381                         /*
5382                          * Blocks are going to be removed from the inode. Wait
5383                          * for dio in flight.
5384                          */
5385                         inode_dio_wait(inode);
5386                 }
5387
5388                 filemap_invalidate_lock(inode->i_mapping);
5389
5390                 rc = ext4_break_layouts(inode);
5391                 if (rc) {
5392                         filemap_invalidate_unlock(inode->i_mapping);
5393                         goto err_out;
5394                 }
5395
5396                 if (attr->ia_size != inode->i_size) {
5397                         handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5398                         if (IS_ERR(handle)) {
5399                                 error = PTR_ERR(handle);
5400                                 goto out_mmap_sem;
5401                         }
5402                         if (ext4_handle_valid(handle) && shrink) {
5403                                 error = ext4_orphan_add(handle, inode);
5404                                 orphan = 1;
5405                         }
5406                         /*
5407                          * Update c/mtime on truncate up, ext4_truncate() will
5408                          * update c/mtime in shrink case below
5409                          */
5410                         if (!shrink) {
5411                                 inode->i_mtime = current_time(inode);
5412                                 inode->i_ctime = inode->i_mtime;
5413                         }
5414
5415                         if (shrink)
5416                                 ext4_fc_track_range(handle, inode,
5417                                         (attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5418                                         inode->i_sb->s_blocksize_bits,
5419                                         (oldsize > 0 ? oldsize - 1 : 0) >>
5420                                         inode->i_sb->s_blocksize_bits);
5421                         else
5422                                 ext4_fc_track_range(
5423                                         handle, inode,
5424                                         (oldsize > 0 ? oldsize - 1 : oldsize) >>
5425                                         inode->i_sb->s_blocksize_bits,
5426                                         (attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5427                                         inode->i_sb->s_blocksize_bits);
5428
5429                         down_write(&EXT4_I(inode)->i_data_sem);
5430                         EXT4_I(inode)->i_disksize = attr->ia_size;
5431                         rc = ext4_mark_inode_dirty(handle, inode);
5432                         if (!error)
5433                                 error = rc;
5434                         /*
5435                          * We have to update i_size under i_data_sem together
5436                          * with i_disksize to avoid races with writeback code
5437                          * running ext4_wb_update_i_disksize().
5438                          */
5439                         if (!error)
5440                                 i_size_write(inode, attr->ia_size);
5441                         up_write(&EXT4_I(inode)->i_data_sem);
5442                         ext4_journal_stop(handle);
5443                         if (error)
5444                                 goto out_mmap_sem;
5445                         if (!shrink) {
5446                                 pagecache_isize_extended(inode, oldsize,
5447                                                          inode->i_size);
5448                         } else if (ext4_should_journal_data(inode)) {
5449                                 ext4_wait_for_tail_page_commit(inode);
5450                         }
5451                 }
5452
5453                 /*
5454                  * Truncate pagecache after we've waited for commit
5455                  * in data=journal mode to make pages freeable.
5456                  */
5457                 truncate_pagecache(inode, inode->i_size);
5458                 /*
5459                  * Call ext4_truncate() even if i_size didn't change to
5460                  * truncate possible preallocated blocks.
5461                  */
5462                 if (attr->ia_size <= oldsize) {
5463                         rc = ext4_truncate(inode);
5464                         if (rc)
5465                                 error = rc;
5466                 }
5467 out_mmap_sem:
5468                 filemap_invalidate_unlock(inode->i_mapping);
5469         }
5470
5471         if (!error) {
5472                 setattr_copy(mnt_userns, inode, attr);
5473                 mark_inode_dirty(inode);
5474         }
5475
5476         /*
5477          * If the call to ext4_truncate failed to get a transaction handle at
5478          * all, we need to clean up the in-core orphan list manually.
5479          */
5480         if (orphan && inode->i_nlink)
5481                 ext4_orphan_del(NULL, inode);
5482
5483         if (!error && (ia_valid & ATTR_MODE))
5484                 rc = posix_acl_chmod(mnt_userns, inode, inode->i_mode);
5485
5486 err_out:
5487         if  (error)
5488                 ext4_std_error(inode->i_sb, error);
5489         if (!error)
5490                 error = rc;
5491         ext4_fc_stop_update(inode);
5492         return error;
5493 }
5494
5495 int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
5496                  struct kstat *stat, u32 request_mask, unsigned int query_flags)
5497 {
5498         struct inode *inode = d_inode(path->dentry);
5499         struct ext4_inode *raw_inode;
5500         struct ext4_inode_info *ei = EXT4_I(inode);
5501         unsigned int flags;
5502
5503         if ((request_mask & STATX_BTIME) &&
5504             EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
5505                 stat->result_mask |= STATX_BTIME;
5506                 stat->btime.tv_sec = ei->i_crtime.tv_sec;
5507                 stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5508         }
5509
5510         flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5511         if (flags & EXT4_APPEND_FL)
5512                 stat->attributes |= STATX_ATTR_APPEND;
5513         if (flags & EXT4_COMPR_FL)
5514                 stat->attributes |= STATX_ATTR_COMPRESSED;
5515         if (flags & EXT4_ENCRYPT_FL)
5516                 stat->attributes |= STATX_ATTR_ENCRYPTED;
5517         if (flags & EXT4_IMMUTABLE_FL)
5518                 stat->attributes |= STATX_ATTR_IMMUTABLE;
5519         if (flags & EXT4_NODUMP_FL)
5520                 stat->attributes |= STATX_ATTR_NODUMP;
5521         if (flags & EXT4_VERITY_FL)
5522                 stat->attributes |= STATX_ATTR_VERITY;
5523
5524         stat->attributes_mask |= (STATX_ATTR_APPEND |
5525                                   STATX_ATTR_COMPRESSED |
5526                                   STATX_ATTR_ENCRYPTED |
5527                                   STATX_ATTR_IMMUTABLE |
5528                                   STATX_ATTR_NODUMP |
5529                                   STATX_ATTR_VERITY);
5530
5531         generic_fillattr(mnt_userns, inode, stat);
5532         return 0;
5533 }
5534
5535 int ext4_file_getattr(struct user_namespace *mnt_userns,
5536                       const struct path *path, struct kstat *stat,
5537                       u32 request_mask, unsigned int query_flags)
5538 {
5539         struct inode *inode = d_inode(path->dentry);
5540         u64 delalloc_blocks;
5541
5542         ext4_getattr(mnt_userns, path, stat, request_mask, query_flags);
5543
5544         /*
5545          * If there is inline data in the inode, the inode will normally not
5546          * have data blocks allocated (it may have an external xattr block).
5547          * Report at least one sector for such files, so tools like tar, rsync,
5548          * others don't incorrectly think the file is completely sparse.
5549          */
5550         if (unlikely(ext4_has_inline_data(inode)))
5551                 stat->blocks += (stat->size + 511) >> 9;
5552
5553         /*
5554          * We can't update i_blocks if the block allocation is delayed
5555          * otherwise in the case of system crash before the real block
5556          * allocation is done, we will have i_blocks inconsistent with
5557          * on-disk file blocks.
5558          * We always keep i_blocks updated together with real
5559          * allocation. But to not confuse with user, stat
5560          * will return the blocks that include the delayed allocation
5561          * blocks for this file.
5562          */
5563         delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5564                                    EXT4_I(inode)->i_reserved_data_blocks);
5565         stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5566         return 0;
5567 }
5568
5569 static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5570                                    int pextents)
5571 {
5572         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5573                 return ext4_ind_trans_blocks(inode, lblocks);
5574         return ext4_ext_index_trans_blocks(inode, pextents);
5575 }
5576
5577 /*
5578  * Account for index blocks, block groups bitmaps and block group
5579  * descriptor blocks if modify datablocks and index blocks
5580  * worse case, the indexs blocks spread over different block groups
5581  *
5582  * If datablocks are discontiguous, they are possible to spread over
5583  * different block groups too. If they are contiguous, with flexbg,
5584  * they could still across block group boundary.
5585  *
5586  * Also account for superblock, inode, quota and xattr blocks
5587  */
5588 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5589                                   int pextents)
5590 {
5591         ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5592         int gdpblocks;
5593         int idxblocks;
5594         int ret = 0;
5595
5596         /*
5597          * How many index blocks need to touch to map @lblocks logical blocks
5598          * to @pextents physical extents?
5599          */
5600         idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5601
5602         ret = idxblocks;
5603
5604         /*
5605          * Now let's see how many group bitmaps and group descriptors need
5606          * to account
5607          */
5608         groups = idxblocks + pextents;
5609         gdpblocks = groups;
5610         if (groups > ngroups)
5611                 groups = ngroups;
5612         if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5613                 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5614
5615         /* bitmaps and block group descriptor blocks */
5616         ret += groups + gdpblocks;
5617
5618         /* Blocks for super block, inode, quota and xattr blocks */
5619         ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5620
5621         return ret;
5622 }
5623
5624 /*
5625  * Calculate the total number of credits to reserve to fit
5626  * the modification of a single pages into a single transaction,
5627  * which may include multiple chunks of block allocations.
5628  *
5629  * This could be called via ext4_write_begin()
5630  *
5631  * We need to consider the worse case, when
5632  * one new block per extent.
5633  */
5634 int ext4_writepage_trans_blocks(struct inode *inode)
5635 {
5636         int bpp = ext4_journal_blocks_per_page(inode);
5637         int ret;
5638
5639         ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5640
5641         /* Account for data blocks for journalled mode */
5642         if (ext4_should_journal_data(inode))
5643                 ret += bpp;
5644         return ret;
5645 }
5646
5647 /*
5648  * Calculate the journal credits for a chunk of data modification.
5649  *
5650  * This is called from DIO, fallocate or whoever calling
5651  * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5652  *
5653  * journal buffers for data blocks are not included here, as DIO
5654  * and fallocate do no need to journal data buffers.
5655  */
5656 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5657 {
5658         return ext4_meta_trans_blocks(inode, nrblocks, 1);
5659 }
5660
5661 /*
5662  * The caller must have previously called ext4_reserve_inode_write().
5663  * Give this, we know that the caller already has write access to iloc->bh.
5664  */
5665 int ext4_mark_iloc_dirty(handle_t *handle,
5666                          struct inode *inode, struct ext4_iloc *iloc)
5667 {
5668         int err = 0;
5669
5670         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
5671                 put_bh(iloc->bh);
5672                 return -EIO;
5673         }
5674         ext4_fc_track_inode(handle, inode);
5675
5676         if (IS_I_VERSION(inode))
5677                 inode_inc_iversion(inode);
5678
5679         /* the do_update_inode consumes one bh->b_count */
5680         get_bh(iloc->bh);
5681
5682         /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5683         err = ext4_do_update_inode(handle, inode, iloc);
5684         put_bh(iloc->bh);
5685         return err;
5686 }
5687
5688 /*
5689  * On success, We end up with an outstanding reference count against
5690  * iloc->bh.  This _must_ be cleaned up later.
5691  */
5692
5693 int
5694 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5695                          struct ext4_iloc *iloc)
5696 {
5697         int err;
5698
5699         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5700                 return -EIO;
5701
5702         err = ext4_get_inode_loc(inode, iloc);
5703         if (!err) {
5704                 BUFFER_TRACE(iloc->bh, "get_write_access");
5705                 err = ext4_journal_get_write_access(handle, inode->i_sb,
5706                                                     iloc->bh, EXT4_JTR_NONE);
5707                 if (err) {
5708                         brelse(iloc->bh);
5709                         iloc->bh = NULL;
5710                 }
5711         }
5712         ext4_std_error(inode->i_sb, err);
5713         return err;
5714 }
5715
5716 static int __ext4_expand_extra_isize(struct inode *inode,
5717                                      unsigned int new_extra_isize,
5718                                      struct ext4_iloc *iloc,
5719                                      handle_t *handle, int *no_expand)
5720 {
5721         struct ext4_inode *raw_inode;
5722         struct ext4_xattr_ibody_header *header;
5723         unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5724         struct ext4_inode_info *ei = EXT4_I(inode);
5725         int error;
5726
5727         /* this was checked at iget time, but double check for good measure */
5728         if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
5729             (ei->i_extra_isize & 3)) {
5730                 EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
5731                                  ei->i_extra_isize,
5732                                  EXT4_INODE_SIZE(inode->i_sb));
5733                 return -EFSCORRUPTED;
5734         }
5735         if ((new_extra_isize < ei->i_extra_isize) ||
5736             (new_extra_isize < 4) ||
5737             (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
5738                 return -EINVAL; /* Should never happen */
5739
5740         raw_inode = ext4_raw_inode(iloc);
5741
5742         header = IHDR(inode, raw_inode);
5743
5744         /* No extended attributes present */
5745         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5746             header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5747                 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5748                        EXT4_I(inode)->i_extra_isize, 0,
5749                        new_extra_isize - EXT4_I(inode)->i_extra_isize);
5750                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5751                 return 0;
5752         }
5753
5754         /* try to expand with EAs present */
5755         error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5756                                            raw_inode, handle);
5757         if (error) {
5758                 /*
5759                  * Inode size expansion failed; don't try again
5760                  */
5761                 *no_expand = 1;
5762         }
5763
5764         return error;
5765 }
5766
5767 /*
5768  * Expand an inode by new_extra_isize bytes.
5769  * Returns 0 on success or negative error number on failure.
5770  */
5771 static int ext4_try_to_expand_extra_isize(struct inode *inode,
5772                                           unsigned int new_extra_isize,
5773                                           struct ext4_iloc iloc,
5774                                           handle_t *handle)
5775 {
5776         int no_expand;
5777         int error;
5778
5779         if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5780                 return -EOVERFLOW;
5781
5782         /*
5783          * In nojournal mode, we can immediately attempt to expand
5784          * the inode.  When journaled, we first need to obtain extra
5785          * buffer credits since we may write into the EA block
5786          * with this same handle. If journal_extend fails, then it will
5787          * only result in a minor loss of functionality for that inode.
5788          * If this is felt to be critical, then e2fsck should be run to
5789          * force a large enough s_min_extra_isize.
5790          */
5791         if (ext4_journal_extend(handle,
5792                                 EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
5793                 return -ENOSPC;
5794
5795         if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5796                 return -EBUSY;
5797
5798         error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5799                                           handle, &no_expand);
5800         ext4_write_unlock_xattr(inode, &no_expand);
5801
5802         return error;
5803 }
5804
5805 int ext4_expand_extra_isize(struct inode *inode,
5806                             unsigned int new_extra_isize,
5807                             struct ext4_iloc *iloc)
5808 {
5809         handle_t *handle;
5810         int no_expand;
5811         int error, rc;
5812
5813         if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5814                 brelse(iloc->bh);
5815                 return -EOVERFLOW;
5816         }
5817
5818         handle = ext4_journal_start(inode, EXT4_HT_INODE,
5819                                     EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5820         if (IS_ERR(handle)) {
5821                 error = PTR_ERR(handle);
5822                 brelse(iloc->bh);
5823                 return error;
5824         }
5825
5826         ext4_write_lock_xattr(inode, &no_expand);
5827
5828         BUFFER_TRACE(iloc->bh, "get_write_access");
5829         error = ext4_journal_get_write_access(handle, inode->i_sb, iloc->bh,
5830                                               EXT4_JTR_NONE);
5831         if (error) {
5832                 brelse(iloc->bh);
5833                 goto out_unlock;
5834         }
5835
5836         error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5837                                           handle, &no_expand);
5838
5839         rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5840         if (!error)
5841                 error = rc;
5842
5843 out_unlock:
5844         ext4_write_unlock_xattr(inode, &no_expand);
5845         ext4_journal_stop(handle);
5846         return error;
5847 }
5848
5849 /*
5850  * What we do here is to mark the in-core inode as clean with respect to inode
5851  * dirtiness (it may still be data-dirty).
5852  * This means that the in-core inode may be reaped by prune_icache
5853  * without having to perform any I/O.  This is a very good thing,
5854  * because *any* task may call prune_icache - even ones which
5855  * have a transaction open against a different journal.
5856  *
5857  * Is this cheating?  Not really.  Sure, we haven't written the
5858  * inode out, but prune_icache isn't a user-visible syncing function.
5859  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5860  * we start and wait on commits.
5861  */
5862 int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
5863                                 const char *func, unsigned int line)
5864 {
5865         struct ext4_iloc iloc;
5866         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5867         int err;
5868
5869         might_sleep();
5870         trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5871         err = ext4_reserve_inode_write(handle, inode, &iloc);
5872         if (err)
5873                 goto out;
5874
5875         if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5876                 ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5877                                                iloc, handle);
5878
5879         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5880 out:
5881         if (unlikely(err))
5882                 ext4_error_inode_err(inode, func, line, 0, err,
5883                                         "mark_inode_dirty error");
5884         return err;
5885 }
5886
5887 /*
5888  * ext4_dirty_inode() is called from __mark_inode_dirty()
5889  *
5890  * We're really interested in the case where a file is being extended.
5891  * i_size has been changed by generic_commit_write() and we thus need
5892  * to include the updated inode in the current transaction.
5893  *
5894  * Also, dquot_alloc_block() will always dirty the inode when blocks
5895  * are allocated to the file.
5896  *
5897  * If the inode is marked synchronous, we don't honour that here - doing
5898  * so would cause a commit on atime updates, which we don't bother doing.
5899  * We handle synchronous inodes at the highest possible level.
5900  */
5901 void ext4_dirty_inode(struct inode *inode, int flags)
5902 {
5903         handle_t *handle;
5904
5905         handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5906         if (IS_ERR(handle))
5907                 return;
5908         ext4_mark_inode_dirty(handle, inode);
5909         ext4_journal_stop(handle);
5910 }
5911
5912 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5913 {
5914         journal_t *journal;
5915         handle_t *handle;
5916         int err;
5917         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5918
5919         /*
5920          * We have to be very careful here: changing a data block's
5921          * journaling status dynamically is dangerous.  If we write a
5922          * data block to the journal, change the status and then delete
5923          * that block, we risk forgetting to revoke the old log record
5924          * from the journal and so a subsequent replay can corrupt data.
5925          * So, first we make sure that the journal is empty and that
5926          * nobody is changing anything.
5927          */
5928
5929         journal = EXT4_JOURNAL(inode);
5930         if (!journal)
5931                 return 0;
5932         if (is_journal_aborted(journal))
5933                 return -EROFS;
5934
5935         /* Wait for all existing dio workers */
5936         inode_dio_wait(inode);
5937
5938         /*
5939          * Before flushing the journal and switching inode's aops, we have
5940          * to flush all dirty data the inode has. There can be outstanding
5941          * delayed allocations, there can be unwritten extents created by
5942          * fallocate or buffered writes in dioread_nolock mode covered by
5943          * dirty data which can be converted only after flushing the dirty
5944          * data (and journalled aops don't know how to handle these cases).
5945          */
5946         if (val) {
5947                 filemap_invalidate_lock(inode->i_mapping);
5948                 err = filemap_write_and_wait(inode->i_mapping);
5949                 if (err < 0) {
5950                         filemap_invalidate_unlock(inode->i_mapping);
5951                         return err;
5952                 }
5953         }
5954
5955         percpu_down_write(&sbi->s_writepages_rwsem);
5956         jbd2_journal_lock_updates(journal);
5957
5958         /*
5959          * OK, there are no updates running now, and all cached data is
5960          * synced to disk.  We are now in a completely consistent state
5961          * which doesn't have anything in the journal, and we know that
5962          * no filesystem updates are running, so it is safe to modify
5963          * the inode's in-core data-journaling state flag now.
5964          */
5965
5966         if (val)
5967                 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5968         else {
5969                 err = jbd2_journal_flush(journal, 0);
5970                 if (err < 0) {
5971                         jbd2_journal_unlock_updates(journal);
5972                         percpu_up_write(&sbi->s_writepages_rwsem);
5973                         return err;
5974                 }
5975                 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5976         }
5977         ext4_set_aops(inode);
5978
5979         jbd2_journal_unlock_updates(journal);
5980         percpu_up_write(&sbi->s_writepages_rwsem);
5981
5982         if (val)
5983                 filemap_invalidate_unlock(inode->i_mapping);
5984
5985         /* Finally we can mark the inode as dirty. */
5986
5987         handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
5988         if (IS_ERR(handle))
5989                 return PTR_ERR(handle);
5990
5991         ext4_fc_mark_ineligible(inode->i_sb,
5992                 EXT4_FC_REASON_JOURNAL_FLAG_CHANGE);
5993         err = ext4_mark_inode_dirty(handle, inode);
5994         ext4_handle_sync(handle);
5995         ext4_journal_stop(handle);
5996         ext4_std_error(inode->i_sb, err);
5997
5998         return err;
5999 }
6000
6001 static int ext4_bh_unmapped(handle_t *handle, struct inode *inode,
6002                             struct buffer_head *bh)
6003 {
6004         return !buffer_mapped(bh);
6005 }
6006
6007 vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
6008 {
6009         struct vm_area_struct *vma = vmf->vma;
6010         struct page *page = vmf->page;
6011         loff_t size;
6012         unsigned long len;
6013         int err;
6014         vm_fault_t ret;
6015         struct file *file = vma->vm_file;
6016         struct inode *inode = file_inode(file);
6017         struct address_space *mapping = inode->i_mapping;
6018         handle_t *handle;
6019         get_block_t *get_block;
6020         int retries = 0;
6021
6022         if (unlikely(IS_IMMUTABLE(inode)))
6023                 return VM_FAULT_SIGBUS;
6024
6025         sb_start_pagefault(inode->i_sb);
6026         file_update_time(vma->vm_file);
6027
6028         filemap_invalidate_lock_shared(mapping);
6029
6030         err = ext4_convert_inline_data(inode);
6031         if (err)
6032                 goto out_ret;
6033
6034         /*
6035          * On data journalling we skip straight to the transaction handle:
6036          * there's no delalloc; page truncated will be checked later; the
6037          * early return w/ all buffers mapped (calculates size/len) can't
6038          * be used; and there's no dioread_nolock, so only ext4_get_block.
6039          */
6040         if (ext4_should_journal_data(inode))
6041                 goto retry_alloc;
6042
6043         /* Delalloc case is easy... */
6044         if (test_opt(inode->i_sb, DELALLOC) &&
6045             !ext4_nonda_switch(inode->i_sb)) {
6046                 do {
6047                         err = block_page_mkwrite(vma, vmf,
6048                                                    ext4_da_get_block_prep);
6049                 } while (err == -ENOSPC &&
6050                        ext4_should_retry_alloc(inode->i_sb, &retries));
6051                 goto out_ret;
6052         }
6053
6054         lock_page(page);
6055         size = i_size_read(inode);
6056         /* Page got truncated from under us? */
6057         if (page->mapping != mapping || page_offset(page) > size) {
6058                 unlock_page(page);
6059                 ret = VM_FAULT_NOPAGE;
6060                 goto out;
6061         }
6062
6063         if (page->index == size >> PAGE_SHIFT)
6064                 len = size & ~PAGE_MASK;
6065         else
6066                 len = PAGE_SIZE;
6067         /*
6068          * Return if we have all the buffers mapped. This avoids the need to do
6069          * journal_start/journal_stop which can block and take a long time
6070          *
6071          * This cannot be done for data journalling, as we have to add the
6072          * inode to the transaction's list to writeprotect pages on commit.
6073          */
6074         if (page_has_buffers(page)) {
6075                 if (!ext4_walk_page_buffers(NULL, inode, page_buffers(page),
6076                                             0, len, NULL,
6077                                             ext4_bh_unmapped)) {
6078                         /* Wait so that we don't change page under IO */
6079                         wait_for_stable_page(page);
6080                         ret = VM_FAULT_LOCKED;
6081                         goto out;
6082                 }
6083         }
6084         unlock_page(page);
6085         /* OK, we need to fill the hole... */
6086         if (ext4_should_dioread_nolock(inode))
6087                 get_block = ext4_get_block_unwritten;
6088         else
6089                 get_block = ext4_get_block;
6090 retry_alloc:
6091         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6092                                     ext4_writepage_trans_blocks(inode));
6093         if (IS_ERR(handle)) {
6094                 ret = VM_FAULT_SIGBUS;
6095                 goto out;
6096         }
6097         /*
6098          * Data journalling can't use block_page_mkwrite() because it
6099          * will set_buffer_dirty() before do_journal_get_write_access()
6100          * thus might hit warning messages for dirty metadata buffers.
6101          */
6102         if (!ext4_should_journal_data(inode)) {
6103                 err = block_page_mkwrite(vma, vmf, get_block);
6104         } else {
6105                 lock_page(page);
6106                 size = i_size_read(inode);
6107                 /* Page got truncated from under us? */
6108                 if (page->mapping != mapping || page_offset(page) > size) {
6109                         ret = VM_FAULT_NOPAGE;
6110                         goto out_error;
6111                 }
6112
6113                 if (page->index == size >> PAGE_SHIFT)
6114                         len = size & ~PAGE_MASK;
6115                 else
6116                         len = PAGE_SIZE;
6117
6118                 err = __block_write_begin(page, 0, len, ext4_get_block);
6119                 if (!err) {
6120                         ret = VM_FAULT_SIGBUS;
6121                         if (ext4_walk_page_buffers(handle, inode,
6122                                         page_buffers(page), 0, len, NULL,
6123                                         do_journal_get_write_access))
6124                                 goto out_error;
6125                         if (ext4_walk_page_buffers(handle, inode,
6126                                         page_buffers(page), 0, len, NULL,
6127                                         write_end_fn))
6128                                 goto out_error;
6129                         if (ext4_jbd2_inode_add_write(handle, inode,
6130                                                       page_offset(page), len))
6131                                 goto out_error;
6132                         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
6133                 } else {
6134                         unlock_page(page);
6135                 }
6136         }
6137         ext4_journal_stop(handle);
6138         if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6139                 goto retry_alloc;
6140 out_ret:
6141         ret = block_page_mkwrite_return(err);
6142 out:
6143         filemap_invalidate_unlock_shared(mapping);
6144         sb_end_pagefault(inode->i_sb);
6145         return ret;
6146 out_error:
6147         unlock_page(page);
6148         ext4_journal_stop(handle);
6149         goto out;
6150 }