perf data: Add is_perf_data function
[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/time.h>
24 #include <linux/highuid.h>
25 #include <linux/pagemap.h>
26 #include <linux/dax.h>
27 #include <linux/quotaops.h>
28 #include <linux/string.h>
29 #include <linux/buffer_head.h>
30 #include <linux/writeback.h>
31 #include <linux/pagevec.h>
32 #include <linux/mpage.h>
33 #include <linux/namei.h>
34 #include <linux/uio.h>
35 #include <linux/bio.h>
36 #include <linux/workqueue.h>
37 #include <linux/kernel.h>
38 #include <linux/printk.h>
39 #include <linux/slab.h>
40 #include <linux/bitops.h>
41 #include <linux/iomap.h>
42 #include <linux/iversion.h>
43
44 #include "ext4_jbd2.h"
45 #include "xattr.h"
46 #include "acl.h"
47 #include "truncate.h"
48
49 #include <trace/events/ext4.h>
50
51 static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
52                               struct ext4_inode_info *ei)
53 {
54         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
55         __u32 csum;
56         __u16 dummy_csum = 0;
57         int offset = offsetof(struct ext4_inode, i_checksum_lo);
58         unsigned int csum_size = sizeof(dummy_csum);
59
60         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
61         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
62         offset += csum_size;
63         csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
64                            EXT4_GOOD_OLD_INODE_SIZE - offset);
65
66         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
67                 offset = offsetof(struct ext4_inode, i_checksum_hi);
68                 csum = ext4_chksum(sbi, csum, (__u8 *)raw +
69                                    EXT4_GOOD_OLD_INODE_SIZE,
70                                    offset - EXT4_GOOD_OLD_INODE_SIZE);
71                 if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
72                         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
73                                            csum_size);
74                         offset += csum_size;
75                 }
76                 csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
77                                    EXT4_INODE_SIZE(inode->i_sb) - offset);
78         }
79
80         return csum;
81 }
82
83 static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
84                                   struct ext4_inode_info *ei)
85 {
86         __u32 provided, calculated;
87
88         if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
89             cpu_to_le32(EXT4_OS_LINUX) ||
90             !ext4_has_metadata_csum(inode->i_sb))
91                 return 1;
92
93         provided = le16_to_cpu(raw->i_checksum_lo);
94         calculated = ext4_inode_csum(inode, raw, ei);
95         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
96             EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
97                 provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
98         else
99                 calculated &= 0xFFFF;
100
101         return provided == calculated;
102 }
103
104 void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
105                          struct ext4_inode_info *ei)
106 {
107         __u32 csum;
108
109         if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
110             cpu_to_le32(EXT4_OS_LINUX) ||
111             !ext4_has_metadata_csum(inode->i_sb))
112                 return;
113
114         csum = ext4_inode_csum(inode, raw, ei);
115         raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
116         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
117             EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
118                 raw->i_checksum_hi = cpu_to_le16(csum >> 16);
119 }
120
121 static inline int ext4_begin_ordered_truncate(struct inode *inode,
122                                               loff_t new_size)
123 {
124         trace_ext4_begin_ordered_truncate(inode, new_size);
125         /*
126          * If jinode is zero, then we never opened the file for
127          * writing, so there's no need to call
128          * jbd2_journal_begin_ordered_truncate() since there's no
129          * outstanding writes we need to flush.
130          */
131         if (!EXT4_I(inode)->jinode)
132                 return 0;
133         return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
134                                                    EXT4_I(inode)->jinode,
135                                                    new_size);
136 }
137
138 static void ext4_invalidatepage(struct page *page, unsigned int offset,
139                                 unsigned int length);
140 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
141 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
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
179         trace_ext4_evict_inode(inode);
180
181         if (inode->i_nlink) {
182                 /*
183                  * When journalling data dirty buffers are tracked only in the
184                  * journal. So although mm thinks everything is clean and
185                  * ready for reaping the inode might still have some pages to
186                  * write in the running transaction or waiting to be
187                  * checkpointed. Thus calling jbd2_journal_invalidatepage()
188                  * (via truncate_inode_pages()) to discard these buffers can
189                  * cause data loss. Also even if we did not discard these
190                  * buffers, we would have no way to find them after the inode
191                  * is reaped and thus user could see stale data if he tries to
192                  * read them before the transaction is checkpointed. So be
193                  * careful and force everything to disk here... We use
194                  * ei->i_datasync_tid to store the newest transaction
195                  * containing inode's data.
196                  *
197                  * Note that directories do not have this problem because they
198                  * don't use page cache.
199                  */
200                 if (inode->i_ino != EXT4_JOURNAL_INO &&
201                     ext4_should_journal_data(inode) &&
202                     (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
203                     inode->i_data.nrpages) {
204                         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
205                         tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
206
207                         jbd2_complete_transaction(journal, commit_tid);
208                         filemap_write_and_wait(&inode->i_data);
209                 }
210                 truncate_inode_pages_final(&inode->i_data);
211
212                 goto no_delete;
213         }
214
215         if (is_bad_inode(inode))
216                 goto no_delete;
217         dquot_initialize(inode);
218
219         if (ext4_should_order_data(inode))
220                 ext4_begin_ordered_truncate(inode, 0);
221         truncate_inode_pages_final(&inode->i_data);
222
223         /*
224          * For inodes with journalled data, transaction commit could have
225          * dirtied the inode. Flush worker is ignoring it because of I_FREEING
226          * flag but we still need to remove the inode from the writeback lists.
227          */
228         if (!list_empty_careful(&inode->i_io_list)) {
229                 WARN_ON_ONCE(!ext4_should_journal_data(inode));
230                 inode_io_list_del(inode);
231         }
232
233         /*
234          * Protect us against freezing - iput() caller didn't have to have any
235          * protection against it
236          */
237         sb_start_intwrite(inode->i_sb);
238
239         if (!IS_NOQUOTA(inode))
240                 extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
241
242         /*
243          * Block bitmap, group descriptor, and inode are accounted in both
244          * ext4_blocks_for_truncate() and extra_credits. So subtract 3.
245          */
246         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
247                          ext4_blocks_for_truncate(inode) + extra_credits - 3);
248         if (IS_ERR(handle)) {
249                 ext4_std_error(inode->i_sb, PTR_ERR(handle));
250                 /*
251                  * If we're going to skip the normal cleanup, we still need to
252                  * make sure that the in-core orphan linked list is properly
253                  * cleaned up.
254                  */
255                 ext4_orphan_del(NULL, inode);
256                 sb_end_intwrite(inode->i_sb);
257                 goto no_delete;
258         }
259
260         if (IS_SYNC(inode))
261                 ext4_handle_sync(handle);
262
263         /*
264          * Set inode->i_size to 0 before calling ext4_truncate(). We need
265          * special handling of symlinks here because i_size is used to
266          * determine whether ext4_inode_info->i_data contains symlink data or
267          * block mappings. Setting i_size to 0 will remove its fast symlink
268          * status. Erase i_data so that it becomes a valid empty block map.
269          */
270         if (ext4_inode_is_fast_symlink(inode))
271                 memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
272         inode->i_size = 0;
273         err = ext4_mark_inode_dirty(handle, inode);
274         if (err) {
275                 ext4_warning(inode->i_sb,
276                              "couldn't mark inode dirty (err %d)", err);
277                 goto stop_handle;
278         }
279         if (inode->i_blocks) {
280                 err = ext4_truncate(inode);
281                 if (err) {
282                         ext4_error_err(inode->i_sb, -err,
283                                        "couldn't truncate inode %lu (err %d)",
284                                        inode->i_ino, err);
285                         goto stop_handle;
286                 }
287         }
288
289         /* Remove xattr references. */
290         err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
291                                       extra_credits);
292         if (err) {
293                 ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
294 stop_handle:
295                 ext4_journal_stop(handle);
296                 ext4_orphan_del(NULL, inode);
297                 sb_end_intwrite(inode->i_sb);
298                 ext4_xattr_inode_array_free(ea_inode_array);
299                 goto no_delete;
300         }
301
302         /*
303          * Kill off the orphan record which ext4_truncate created.
304          * AKPM: I think this can be inside the above `if'.
305          * Note that ext4_orphan_del() has to be able to cope with the
306          * deletion of a non-existent orphan - this is because we don't
307          * know if ext4_truncate() actually created an orphan record.
308          * (Well, we could do this if we need to, but heck - it works)
309          */
310         ext4_orphan_del(handle, inode);
311         EXT4_I(inode)->i_dtime  = (__u32)ktime_get_real_seconds();
312
313         /*
314          * One subtle ordering requirement: if anything has gone wrong
315          * (transaction abort, IO errors, whatever), then we can still
316          * do these next steps (the fs will already have been marked as
317          * having errors), but we can't free the inode if the mark_dirty
318          * fails.
319          */
320         if (ext4_mark_inode_dirty(handle, inode))
321                 /* If that failed, just do the required in-core inode clear. */
322                 ext4_clear_inode(inode);
323         else
324                 ext4_free_inode(handle, inode);
325         ext4_journal_stop(handle);
326         sb_end_intwrite(inode->i_sb);
327         ext4_xattr_inode_array_free(ea_inode_array);
328         return;
329 no_delete:
330         ext4_clear_inode(inode);        /* We must guarantee clearing of inode... */
331 }
332
333 #ifdef CONFIG_QUOTA
334 qsize_t *ext4_get_reserved_space(struct inode *inode)
335 {
336         return &EXT4_I(inode)->i_reserved_quota;
337 }
338 #endif
339
340 /*
341  * Called with i_data_sem down, which is important since we can call
342  * ext4_discard_preallocations() from here.
343  */
344 void ext4_da_update_reserve_space(struct inode *inode,
345                                         int used, int quota_claim)
346 {
347         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
348         struct ext4_inode_info *ei = EXT4_I(inode);
349
350         spin_lock(&ei->i_block_reservation_lock);
351         trace_ext4_da_update_reserve_space(inode, used, quota_claim);
352         if (unlikely(used > ei->i_reserved_data_blocks)) {
353                 ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
354                          "with only %d reserved data blocks",
355                          __func__, inode->i_ino, used,
356                          ei->i_reserved_data_blocks);
357                 WARN_ON(1);
358                 used = ei->i_reserved_data_blocks;
359         }
360
361         /* Update per-inode reservations */
362         ei->i_reserved_data_blocks -= used;
363         percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
364
365         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
366
367         /* Update quota subsystem for data blocks */
368         if (quota_claim)
369                 dquot_claim_block(inode, EXT4_C2B(sbi, used));
370         else {
371                 /*
372                  * We did fallocate with an offset that is already delayed
373                  * allocated. So on delayed allocated writeback we should
374                  * not re-claim the quota for fallocated blocks.
375                  */
376                 dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
377         }
378
379         /*
380          * If we have done all the pending block allocations and if
381          * there aren't any writers on the inode, we can discard the
382          * inode's preallocations.
383          */
384         if ((ei->i_reserved_data_blocks == 0) &&
385             !inode_is_open_for_write(inode))
386                 ext4_discard_preallocations(inode, 0);
387 }
388
389 static int __check_block_validity(struct inode *inode, const char *func,
390                                 unsigned int line,
391                                 struct ext4_map_blocks *map)
392 {
393         if (ext4_has_feature_journal(inode->i_sb) &&
394             (inode->i_ino ==
395              le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
396                 return 0;
397         if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
398                 ext4_error_inode(inode, func, line, map->m_pblk,
399                                  "lblock %lu mapped to illegal pblock %llu "
400                                  "(length %d)", (unsigned long) map->m_lblk,
401                                  map->m_pblk, map->m_len);
402                 return -EFSCORRUPTED;
403         }
404         return 0;
405 }
406
407 int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
408                        ext4_lblk_t len)
409 {
410         int ret;
411
412         if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
413                 return fscrypt_zeroout_range(inode, lblk, pblk, len);
414
415         ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
416         if (ret > 0)
417                 ret = 0;
418
419         return ret;
420 }
421
422 #define check_block_validity(inode, map)        \
423         __check_block_validity((inode), __func__, __LINE__, (map))
424
425 #ifdef ES_AGGRESSIVE_TEST
426 static void ext4_map_blocks_es_recheck(handle_t *handle,
427                                        struct inode *inode,
428                                        struct ext4_map_blocks *es_map,
429                                        struct ext4_map_blocks *map,
430                                        int flags)
431 {
432         int retval;
433
434         map->m_flags = 0;
435         /*
436          * There is a race window that the result is not the same.
437          * e.g. xfstests #223 when dioread_nolock enables.  The reason
438          * is that we lookup a block mapping in extent status tree with
439          * out taking i_data_sem.  So at the time the unwritten extent
440          * could be converted.
441          */
442         down_read(&EXT4_I(inode)->i_data_sem);
443         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
444                 retval = ext4_ext_map_blocks(handle, inode, map, 0);
445         } else {
446                 retval = ext4_ind_map_blocks(handle, inode, map, 0);
447         }
448         up_read((&EXT4_I(inode)->i_data_sem));
449
450         /*
451          * We don't check m_len because extent will be collpased in status
452          * tree.  So the m_len might not equal.
453          */
454         if (es_map->m_lblk != map->m_lblk ||
455             es_map->m_flags != map->m_flags ||
456             es_map->m_pblk != map->m_pblk) {
457                 printk("ES cache assertion failed for inode: %lu "
458                        "es_cached ex [%d/%d/%llu/%x] != "
459                        "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
460                        inode->i_ino, es_map->m_lblk, es_map->m_len,
461                        es_map->m_pblk, es_map->m_flags, map->m_lblk,
462                        map->m_len, map->m_pblk, map->m_flags,
463                        retval, flags);
464         }
465 }
466 #endif /* ES_AGGRESSIVE_TEST */
467
468 /*
469  * The ext4_map_blocks() function tries to look up the requested blocks,
470  * and returns if the blocks are already mapped.
471  *
472  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
473  * and store the allocated blocks in the result buffer head and mark it
474  * mapped.
475  *
476  * If file type is extents based, it will call ext4_ext_map_blocks(),
477  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
478  * based files
479  *
480  * On success, it returns the number of blocks being mapped or allocated.  if
481  * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
482  * is marked as unwritten. If the create == 1, it will mark @map as mapped.
483  *
484  * It returns 0 if plain look up failed (blocks have not been allocated), in
485  * that case, @map is returned as unmapped but we still do fill map->m_len to
486  * indicate the length of a hole starting at map->m_lblk.
487  *
488  * It returns the error in case of allocation failure.
489  */
490 int ext4_map_blocks(handle_t *handle, struct inode *inode,
491                     struct ext4_map_blocks *map, int flags)
492 {
493         struct extent_status es;
494         int retval;
495         int ret = 0;
496 #ifdef ES_AGGRESSIVE_TEST
497         struct ext4_map_blocks orig_map;
498
499         memcpy(&orig_map, map, sizeof(*map));
500 #endif
501
502         map->m_flags = 0;
503         ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
504                   flags, map->m_len, (unsigned long) map->m_lblk);
505
506         /*
507          * ext4_map_blocks returns an int, and m_len is an unsigned int
508          */
509         if (unlikely(map->m_len > INT_MAX))
510                 map->m_len = INT_MAX;
511
512         /* We can handle the block number less than EXT_MAX_BLOCKS */
513         if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
514                 return -EFSCORRUPTED;
515
516         /* Lookup extent status tree firstly */
517         if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
518             ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
519                 if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
520                         map->m_pblk = ext4_es_pblock(&es) +
521                                         map->m_lblk - es.es_lblk;
522                         map->m_flags |= ext4_es_is_written(&es) ?
523                                         EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
524                         retval = es.es_len - (map->m_lblk - es.es_lblk);
525                         if (retval > map->m_len)
526                                 retval = map->m_len;
527                         map->m_len = retval;
528                 } else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
529                         map->m_pblk = 0;
530                         retval = es.es_len - (map->m_lblk - es.es_lblk);
531                         if (retval > map->m_len)
532                                 retval = map->m_len;
533                         map->m_len = retval;
534                         retval = 0;
535                 } else {
536                         BUG();
537                 }
538 #ifdef ES_AGGRESSIVE_TEST
539                 ext4_map_blocks_es_recheck(handle, inode, map,
540                                            &orig_map, flags);
541 #endif
542                 goto found;
543         }
544
545         /*
546          * Try to see if we can get the block without requesting a new
547          * file system block.
548          */
549         down_read(&EXT4_I(inode)->i_data_sem);
550         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
551                 retval = ext4_ext_map_blocks(handle, inode, map, 0);
552         } else {
553                 retval = ext4_ind_map_blocks(handle, inode, map, 0);
554         }
555         if (retval > 0) {
556                 unsigned int status;
557
558                 if (unlikely(retval != map->m_len)) {
559                         ext4_warning(inode->i_sb,
560                                      "ES len assertion failed for inode "
561                                      "%lu: retval %d != map->m_len %d",
562                                      inode->i_ino, retval, map->m_len);
563                         WARN_ON(1);
564                 }
565
566                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
567                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
568                 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
569                     !(status & EXTENT_STATUS_WRITTEN) &&
570                     ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
571                                        map->m_lblk + map->m_len - 1))
572                         status |= EXTENT_STATUS_DELAYED;
573                 ret = ext4_es_insert_extent(inode, map->m_lblk,
574                                             map->m_len, map->m_pblk, status);
575                 if (ret < 0)
576                         retval = ret;
577         }
578         up_read((&EXT4_I(inode)->i_data_sem));
579
580 found:
581         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
582                 ret = check_block_validity(inode, map);
583                 if (ret != 0)
584                         return ret;
585         }
586
587         /* If it is only a block(s) look up */
588         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
589                 return retval;
590
591         /*
592          * Returns if the blocks have already allocated
593          *
594          * Note that if blocks have been preallocated
595          * ext4_ext_get_block() returns the create = 0
596          * with buffer head unmapped.
597          */
598         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
599                 /*
600                  * If we need to convert extent to unwritten
601                  * we continue and do the actual work in
602                  * ext4_ext_map_blocks()
603                  */
604                 if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
605                         return retval;
606
607         /*
608          * Here we clear m_flags because after allocating an new extent,
609          * it will be set again.
610          */
611         map->m_flags &= ~EXT4_MAP_FLAGS;
612
613         /*
614          * New blocks allocate and/or writing to unwritten extent
615          * will possibly result in updating i_data, so we take
616          * the write lock of i_data_sem, and call get_block()
617          * with create == 1 flag.
618          */
619         down_write(&EXT4_I(inode)->i_data_sem);
620
621         /*
622          * We need to check for EXT4 here because migrate
623          * could have changed the inode type in between
624          */
625         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
626                 retval = ext4_ext_map_blocks(handle, inode, map, flags);
627         } else {
628                 retval = ext4_ind_map_blocks(handle, inode, map, flags);
629
630                 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
631                         /*
632                          * We allocated new blocks which will result in
633                          * i_data's format changing.  Force the migrate
634                          * to fail by clearing migrate flags
635                          */
636                         ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
637                 }
638
639                 /*
640                  * Update reserved blocks/metadata blocks after successful
641                  * block allocation which had been deferred till now. We don't
642                  * support fallocate for non extent files. So we can update
643                  * reserve space here.
644                  */
645                 if ((retval > 0) &&
646                         (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
647                         ext4_da_update_reserve_space(inode, retval, 1);
648         }
649
650         if (retval > 0) {
651                 unsigned int status;
652
653                 if (unlikely(retval != map->m_len)) {
654                         ext4_warning(inode->i_sb,
655                                      "ES len assertion failed for inode "
656                                      "%lu: retval %d != map->m_len %d",
657                                      inode->i_ino, retval, map->m_len);
658                         WARN_ON(1);
659                 }
660
661                 /*
662                  * We have to zeroout blocks before inserting them into extent
663                  * status tree. Otherwise someone could look them up there and
664                  * use them before they are really zeroed. We also have to
665                  * unmap metadata before zeroing as otherwise writeback can
666                  * overwrite zeros with stale data from block device.
667                  */
668                 if (flags & EXT4_GET_BLOCKS_ZERO &&
669                     map->m_flags & EXT4_MAP_MAPPED &&
670                     map->m_flags & EXT4_MAP_NEW) {
671                         ret = ext4_issue_zeroout(inode, map->m_lblk,
672                                                  map->m_pblk, map->m_len);
673                         if (ret) {
674                                 retval = ret;
675                                 goto out_sem;
676                         }
677                 }
678
679                 /*
680                  * If the extent has been zeroed out, we don't need to update
681                  * extent status tree.
682                  */
683                 if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
684                     ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
685                         if (ext4_es_is_written(&es))
686                                 goto out_sem;
687                 }
688                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
689                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
690                 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
691                     !(status & EXTENT_STATUS_WRITTEN) &&
692                     ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
693                                        map->m_lblk + map->m_len - 1))
694                         status |= EXTENT_STATUS_DELAYED;
695                 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
696                                             map->m_pblk, status);
697                 if (ret < 0) {
698                         retval = ret;
699                         goto out_sem;
700                 }
701         }
702
703 out_sem:
704         up_write((&EXT4_I(inode)->i_data_sem));
705         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
706                 ret = check_block_validity(inode, map);
707                 if (ret != 0)
708                         return ret;
709
710                 /*
711                  * Inodes with freshly allocated blocks where contents will be
712                  * visible after transaction commit must be on transaction's
713                  * ordered data list.
714                  */
715                 if (map->m_flags & EXT4_MAP_NEW &&
716                     !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
717                     !(flags & EXT4_GET_BLOCKS_ZERO) &&
718                     !ext4_is_quota_file(inode) &&
719                     ext4_should_order_data(inode)) {
720                         loff_t start_byte =
721                                 (loff_t)map->m_lblk << inode->i_blkbits;
722                         loff_t length = (loff_t)map->m_len << inode->i_blkbits;
723
724                         if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
725                                 ret = ext4_jbd2_inode_add_wait(handle, inode,
726                                                 start_byte, length);
727                         else
728                                 ret = ext4_jbd2_inode_add_write(handle, inode,
729                                                 start_byte, length);
730                         if (ret)
731                                 return ret;
732                 }
733                 ext4_fc_track_range(inode, map->m_lblk,
734                             map->m_lblk + map->m_len - 1);
735         }
736
737         if (retval < 0)
738                 ext_debug(inode, "failed with err %d\n", retval);
739         return retval;
740 }
741
742 /*
743  * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
744  * we have to be careful as someone else may be manipulating b_state as well.
745  */
746 static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
747 {
748         unsigned long old_state;
749         unsigned long new_state;
750
751         flags &= EXT4_MAP_FLAGS;
752
753         /* Dummy buffer_head? Set non-atomically. */
754         if (!bh->b_page) {
755                 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
756                 return;
757         }
758         /*
759          * Someone else may be modifying b_state. Be careful! This is ugly but
760          * once we get rid of using bh as a container for mapping information
761          * to pass to / from get_block functions, this can go away.
762          */
763         do {
764                 old_state = READ_ONCE(bh->b_state);
765                 new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
766         } while (unlikely(
767                  cmpxchg(&bh->b_state, old_state, new_state) != old_state));
768 }
769
770 static int _ext4_get_block(struct inode *inode, sector_t iblock,
771                            struct buffer_head *bh, int flags)
772 {
773         struct ext4_map_blocks map;
774         int ret = 0;
775
776         if (ext4_has_inline_data(inode))
777                 return -ERANGE;
778
779         map.m_lblk = iblock;
780         map.m_len = bh->b_size >> inode->i_blkbits;
781
782         ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
783                               flags);
784         if (ret > 0) {
785                 map_bh(bh, inode->i_sb, map.m_pblk);
786                 ext4_update_bh_state(bh, map.m_flags);
787                 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
788                 ret = 0;
789         } else if (ret == 0) {
790                 /* hole case, need to fill in bh->b_size */
791                 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
792         }
793         return ret;
794 }
795
796 int ext4_get_block(struct inode *inode, sector_t iblock,
797                    struct buffer_head *bh, int create)
798 {
799         return _ext4_get_block(inode, iblock, bh,
800                                create ? EXT4_GET_BLOCKS_CREATE : 0);
801 }
802
803 /*
804  * Get block function used when preparing for buffered write if we require
805  * creating an unwritten extent if blocks haven't been allocated.  The extent
806  * will be converted to written after the IO is complete.
807  */
808 int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
809                              struct buffer_head *bh_result, int create)
810 {
811         ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
812                    inode->i_ino, create);
813         return _ext4_get_block(inode, iblock, bh_result,
814                                EXT4_GET_BLOCKS_IO_CREATE_EXT);
815 }
816
817 /* Maximum number of blocks we map for direct IO at once. */
818 #define DIO_MAX_BLOCKS 4096
819
820 /*
821  * `handle' can be NULL if create is zero
822  */
823 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
824                                 ext4_lblk_t block, int map_flags)
825 {
826         struct ext4_map_blocks map;
827         struct buffer_head *bh;
828         int create = map_flags & EXT4_GET_BLOCKS_CREATE;
829         int err;
830
831         J_ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
832                  || handle != NULL || create == 0);
833
834         map.m_lblk = block;
835         map.m_len = 1;
836         err = ext4_map_blocks(handle, inode, &map, map_flags);
837
838         if (err == 0)
839                 return create ? ERR_PTR(-ENOSPC) : NULL;
840         if (err < 0)
841                 return ERR_PTR(err);
842
843         bh = sb_getblk(inode->i_sb, map.m_pblk);
844         if (unlikely(!bh))
845                 return ERR_PTR(-ENOMEM);
846         if (map.m_flags & EXT4_MAP_NEW) {
847                 J_ASSERT(create != 0);
848                 J_ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
849                          || (handle != NULL));
850
851                 /*
852                  * Now that we do not always journal data, we should
853                  * keep in mind whether this should always journal the
854                  * new buffer as metadata.  For now, regular file
855                  * writes use ext4_get_block instead, so it's not a
856                  * problem.
857                  */
858                 lock_buffer(bh);
859                 BUFFER_TRACE(bh, "call get_create_access");
860                 err = ext4_journal_get_create_access(handle, bh);
861                 if (unlikely(err)) {
862                         unlock_buffer(bh);
863                         goto errout;
864                 }
865                 if (!buffer_uptodate(bh)) {
866                         memset(bh->b_data, 0, inode->i_sb->s_blocksize);
867                         set_buffer_uptodate(bh);
868                 }
869                 unlock_buffer(bh);
870                 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
871                 err = ext4_handle_dirty_metadata(handle, inode, bh);
872                 if (unlikely(err))
873                         goto errout;
874         } else
875                 BUFFER_TRACE(bh, "not a new buffer");
876         return bh;
877 errout:
878         brelse(bh);
879         return ERR_PTR(err);
880 }
881
882 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
883                                ext4_lblk_t block, int map_flags)
884 {
885         struct buffer_head *bh;
886         int ret;
887
888         bh = ext4_getblk(handle, inode, block, map_flags);
889         if (IS_ERR(bh))
890                 return bh;
891         if (!bh || ext4_buffer_uptodate(bh))
892                 return bh;
893
894         ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
895         if (ret) {
896                 put_bh(bh);
897                 return ERR_PTR(ret);
898         }
899         return bh;
900 }
901
902 /* Read a contiguous batch of blocks. */
903 int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
904                      bool wait, struct buffer_head **bhs)
905 {
906         int i, err;
907
908         for (i = 0; i < bh_count; i++) {
909                 bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
910                 if (IS_ERR(bhs[i])) {
911                         err = PTR_ERR(bhs[i]);
912                         bh_count = i;
913                         goto out_brelse;
914                 }
915         }
916
917         for (i = 0; i < bh_count; i++)
918                 /* Note that NULL bhs[i] is valid because of holes. */
919                 if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
920                         ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
921
922         if (!wait)
923                 return 0;
924
925         for (i = 0; i < bh_count; i++)
926                 if (bhs[i])
927                         wait_on_buffer(bhs[i]);
928
929         for (i = 0; i < bh_count; i++) {
930                 if (bhs[i] && !buffer_uptodate(bhs[i])) {
931                         err = -EIO;
932                         goto out_brelse;
933                 }
934         }
935         return 0;
936
937 out_brelse:
938         for (i = 0; i < bh_count; i++) {
939                 brelse(bhs[i]);
940                 bhs[i] = NULL;
941         }
942         return err;
943 }
944
945 int ext4_walk_page_buffers(handle_t *handle,
946                            struct buffer_head *head,
947                            unsigned from,
948                            unsigned to,
949                            int *partial,
950                            int (*fn)(handle_t *handle,
951                                      struct buffer_head *bh))
952 {
953         struct buffer_head *bh;
954         unsigned block_start, block_end;
955         unsigned blocksize = head->b_size;
956         int err, ret = 0;
957         struct buffer_head *next;
958
959         for (bh = head, block_start = 0;
960              ret == 0 && (bh != head || !block_start);
961              block_start = block_end, bh = next) {
962                 next = bh->b_this_page;
963                 block_end = block_start + blocksize;
964                 if (block_end <= from || block_start >= to) {
965                         if (partial && !buffer_uptodate(bh))
966                                 *partial = 1;
967                         continue;
968                 }
969                 err = (*fn)(handle, bh);
970                 if (!ret)
971                         ret = err;
972         }
973         return ret;
974 }
975
976 /*
977  * To preserve ordering, it is essential that the hole instantiation and
978  * the data write be encapsulated in a single transaction.  We cannot
979  * close off a transaction and start a new one between the ext4_get_block()
980  * and the commit_write().  So doing the jbd2_journal_start at the start of
981  * prepare_write() is the right place.
982  *
983  * Also, this function can nest inside ext4_writepage().  In that case, we
984  * *know* that ext4_writepage() has generated enough buffer credits to do the
985  * whole page.  So we won't block on the journal in that case, which is good,
986  * because the caller may be PF_MEMALLOC.
987  *
988  * By accident, ext4 can be reentered when a transaction is open via
989  * quota file writes.  If we were to commit the transaction while thus
990  * reentered, there can be a deadlock - we would be holding a quota
991  * lock, and the commit would never complete if another thread had a
992  * transaction open and was blocking on the quota lock - a ranking
993  * violation.
994  *
995  * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
996  * will _not_ run commit under these circumstances because handle->h_ref
997  * is elevated.  We'll still have enough credits for the tiny quotafile
998  * write.
999  */
1000 int do_journal_get_write_access(handle_t *handle,
1001                                 struct buffer_head *bh)
1002 {
1003         int dirty = buffer_dirty(bh);
1004         int ret;
1005
1006         if (!buffer_mapped(bh) || buffer_freed(bh))
1007                 return 0;
1008         /*
1009          * __block_write_begin() could have dirtied some buffers. Clean
1010          * the dirty bit as jbd2_journal_get_write_access() could complain
1011          * otherwise about fs integrity issues. Setting of the dirty bit
1012          * by __block_write_begin() isn't a real problem here as we clear
1013          * the bit before releasing a page lock and thus writeback cannot
1014          * ever write the buffer.
1015          */
1016         if (dirty)
1017                 clear_buffer_dirty(bh);
1018         BUFFER_TRACE(bh, "get write access");
1019         ret = ext4_journal_get_write_access(handle, bh);
1020         if (!ret && dirty)
1021                 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1022         return ret;
1023 }
1024
1025 #ifdef CONFIG_FS_ENCRYPTION
1026 static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
1027                                   get_block_t *get_block)
1028 {
1029         unsigned from = pos & (PAGE_SIZE - 1);
1030         unsigned to = from + len;
1031         struct inode *inode = page->mapping->host;
1032         unsigned block_start, block_end;
1033         sector_t block;
1034         int err = 0;
1035         unsigned blocksize = inode->i_sb->s_blocksize;
1036         unsigned bbits;
1037         struct buffer_head *bh, *head, *wait[2];
1038         int nr_wait = 0;
1039         int i;
1040
1041         BUG_ON(!PageLocked(page));
1042         BUG_ON(from > PAGE_SIZE);
1043         BUG_ON(to > PAGE_SIZE);
1044         BUG_ON(from > to);
1045
1046         if (!page_has_buffers(page))
1047                 create_empty_buffers(page, blocksize, 0);
1048         head = page_buffers(page);
1049         bbits = ilog2(blocksize);
1050         block = (sector_t)page->index << (PAGE_SHIFT - bbits);
1051
1052         for (bh = head, block_start = 0; bh != head || !block_start;
1053             block++, block_start = block_end, bh = bh->b_this_page) {
1054                 block_end = block_start + blocksize;
1055                 if (block_end <= from || block_start >= to) {
1056                         if (PageUptodate(page)) {
1057                                 if (!buffer_uptodate(bh))
1058                                         set_buffer_uptodate(bh);
1059                         }
1060                         continue;
1061                 }
1062                 if (buffer_new(bh))
1063                         clear_buffer_new(bh);
1064                 if (!buffer_mapped(bh)) {
1065                         WARN_ON(bh->b_size != blocksize);
1066                         err = get_block(inode, block, bh, 1);
1067                         if (err)
1068                                 break;
1069                         if (buffer_new(bh)) {
1070                                 if (PageUptodate(page)) {
1071                                         clear_buffer_new(bh);
1072                                         set_buffer_uptodate(bh);
1073                                         mark_buffer_dirty(bh);
1074                                         continue;
1075                                 }
1076                                 if (block_end > to || block_start < from)
1077                                         zero_user_segments(page, to, block_end,
1078                                                            block_start, from);
1079                                 continue;
1080                         }
1081                 }
1082                 if (PageUptodate(page)) {
1083                         if (!buffer_uptodate(bh))
1084                                 set_buffer_uptodate(bh);
1085                         continue;
1086                 }
1087                 if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1088                     !buffer_unwritten(bh) &&
1089                     (block_start < from || block_end > to)) {
1090                         ext4_read_bh_lock(bh, 0, false);
1091                         wait[nr_wait++] = bh;
1092                 }
1093         }
1094         /*
1095          * If we issued read requests, let them complete.
1096          */
1097         for (i = 0; i < nr_wait; i++) {
1098                 wait_on_buffer(wait[i]);
1099                 if (!buffer_uptodate(wait[i]))
1100                         err = -EIO;
1101         }
1102         if (unlikely(err)) {
1103                 page_zero_new_buffers(page, from, to);
1104         } else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
1105                 for (i = 0; i < nr_wait; i++) {
1106                         int err2;
1107
1108                         err2 = fscrypt_decrypt_pagecache_blocks(page, blocksize,
1109                                                                 bh_offset(wait[i]));
1110                         if (err2) {
1111                                 clear_buffer_uptodate(wait[i]);
1112                                 err = err2;
1113                         }
1114                 }
1115         }
1116
1117         return err;
1118 }
1119 #endif
1120
1121 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1122                             loff_t pos, unsigned len, unsigned flags,
1123                             struct page **pagep, void **fsdata)
1124 {
1125         struct inode *inode = mapping->host;
1126         int ret, needed_blocks;
1127         handle_t *handle;
1128         int retries = 0;
1129         struct page *page;
1130         pgoff_t index;
1131         unsigned from, to;
1132
1133         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
1134                 return -EIO;
1135
1136         trace_ext4_write_begin(inode, pos, len, flags);
1137         /*
1138          * Reserve one block more for addition to orphan list in case
1139          * we allocate blocks but write fails for some reason
1140          */
1141         needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1142         index = pos >> PAGE_SHIFT;
1143         from = pos & (PAGE_SIZE - 1);
1144         to = from + len;
1145
1146         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1147                 ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1148                                                     flags, pagep);
1149                 if (ret < 0)
1150                         return ret;
1151                 if (ret == 1)
1152                         return 0;
1153         }
1154
1155         /*
1156          * grab_cache_page_write_begin() can take a long time if the
1157          * system is thrashing due to memory pressure, or if the page
1158          * is being written back.  So grab it first before we start
1159          * the transaction handle.  This also allows us to allocate
1160          * the page (if needed) without using GFP_NOFS.
1161          */
1162 retry_grab:
1163         page = grab_cache_page_write_begin(mapping, index, flags);
1164         if (!page)
1165                 return -ENOMEM;
1166         unlock_page(page);
1167
1168 retry_journal:
1169         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1170         if (IS_ERR(handle)) {
1171                 put_page(page);
1172                 return PTR_ERR(handle);
1173         }
1174
1175         lock_page(page);
1176         if (page->mapping != mapping) {
1177                 /* The page got truncated from under us */
1178                 unlock_page(page);
1179                 put_page(page);
1180                 ext4_journal_stop(handle);
1181                 goto retry_grab;
1182         }
1183         /* In case writeback began while the page was unlocked */
1184         wait_for_stable_page(page);
1185
1186 #ifdef CONFIG_FS_ENCRYPTION
1187         if (ext4_should_dioread_nolock(inode))
1188                 ret = ext4_block_write_begin(page, pos, len,
1189                                              ext4_get_block_unwritten);
1190         else
1191                 ret = ext4_block_write_begin(page, pos, len,
1192                                              ext4_get_block);
1193 #else
1194         if (ext4_should_dioread_nolock(inode))
1195                 ret = __block_write_begin(page, pos, len,
1196                                           ext4_get_block_unwritten);
1197         else
1198                 ret = __block_write_begin(page, pos, len, ext4_get_block);
1199 #endif
1200         if (!ret && ext4_should_journal_data(inode)) {
1201                 ret = ext4_walk_page_buffers(handle, page_buffers(page),
1202                                              from, to, NULL,
1203                                              do_journal_get_write_access);
1204         }
1205
1206         if (ret) {
1207                 bool extended = (pos + len > inode->i_size) &&
1208                                 !ext4_verity_in_progress(inode);
1209
1210                 unlock_page(page);
1211                 /*
1212                  * __block_write_begin may have instantiated a few blocks
1213                  * outside i_size.  Trim these off again. Don't need
1214                  * i_size_read because we hold i_mutex.
1215                  *
1216                  * Add inode to orphan list in case we crash before
1217                  * truncate finishes
1218                  */
1219                 if (extended && ext4_can_truncate(inode))
1220                         ext4_orphan_add(handle, inode);
1221
1222                 ext4_journal_stop(handle);
1223                 if (extended) {
1224                         ext4_truncate_failed_write(inode);
1225                         /*
1226                          * If truncate failed early the inode might
1227                          * still be on the orphan list; we need to
1228                          * make sure the inode is removed from the
1229                          * orphan list in that case.
1230                          */
1231                         if (inode->i_nlink)
1232                                 ext4_orphan_del(NULL, inode);
1233                 }
1234
1235                 if (ret == -ENOSPC &&
1236                     ext4_should_retry_alloc(inode->i_sb, &retries))
1237                         goto retry_journal;
1238                 put_page(page);
1239                 return ret;
1240         }
1241         *pagep = page;
1242         return ret;
1243 }
1244
1245 /* For write_end() in data=journal mode */
1246 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1247 {
1248         int ret;
1249         if (!buffer_mapped(bh) || buffer_freed(bh))
1250                 return 0;
1251         set_buffer_uptodate(bh);
1252         ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1253         clear_buffer_meta(bh);
1254         clear_buffer_prio(bh);
1255         return ret;
1256 }
1257
1258 /*
1259  * We need to pick up the new inode size which generic_commit_write gave us
1260  * `file' can be NULL - eg, when called from page_symlink().
1261  *
1262  * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1263  * buffers are managed internally.
1264  */
1265 static int ext4_write_end(struct file *file,
1266                           struct address_space *mapping,
1267                           loff_t pos, unsigned len, unsigned copied,
1268                           struct page *page, void *fsdata)
1269 {
1270         handle_t *handle = ext4_journal_current_handle();
1271         struct inode *inode = mapping->host;
1272         loff_t old_size = inode->i_size;
1273         int ret = 0, ret2;
1274         int i_size_changed = 0;
1275         int inline_data = ext4_has_inline_data(inode);
1276         bool verity = ext4_verity_in_progress(inode);
1277
1278         trace_ext4_write_end(inode, pos, len, copied);
1279         if (inline_data) {
1280                 ret = ext4_write_inline_data_end(inode, pos, len,
1281                                                  copied, page);
1282                 if (ret < 0) {
1283                         unlock_page(page);
1284                         put_page(page);
1285                         goto errout;
1286                 }
1287                 copied = ret;
1288         } else
1289                 copied = block_write_end(file, mapping, pos,
1290                                          len, copied, page, fsdata);
1291         /*
1292          * it's important to update i_size while still holding page lock:
1293          * page writeout could otherwise come in and zero beyond i_size.
1294          *
1295          * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1296          * blocks are being written past EOF, so skip the i_size update.
1297          */
1298         if (!verity)
1299                 i_size_changed = ext4_update_inode_size(inode, pos + copied);
1300         unlock_page(page);
1301         put_page(page);
1302
1303         if (old_size < pos && !verity)
1304                 pagecache_isize_extended(inode, old_size, pos);
1305         /*
1306          * Don't mark the inode dirty under page lock. First, it unnecessarily
1307          * makes the holding time of page lock longer. Second, it forces lock
1308          * ordering of page lock and transaction start for journaling
1309          * filesystems.
1310          */
1311         if (i_size_changed || inline_data)
1312                 ret = ext4_mark_inode_dirty(handle, inode);
1313
1314         if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1315                 /* if we have allocated more blocks and copied
1316                  * less. We will have blocks allocated outside
1317                  * inode->i_size. So truncate them
1318                  */
1319                 ext4_orphan_add(handle, inode);
1320 errout:
1321         ret2 = ext4_journal_stop(handle);
1322         if (!ret)
1323                 ret = ret2;
1324
1325         if (pos + len > inode->i_size && !verity) {
1326                 ext4_truncate_failed_write(inode);
1327                 /*
1328                  * If truncate failed early the inode might still be
1329                  * on the orphan list; we need to make sure the inode
1330                  * is removed from the orphan list in that case.
1331                  */
1332                 if (inode->i_nlink)
1333                         ext4_orphan_del(NULL, inode);
1334         }
1335
1336         return ret ? ret : copied;
1337 }
1338
1339 /*
1340  * This is a private version of page_zero_new_buffers() which doesn't
1341  * set the buffer to be dirty, since in data=journalled mode we need
1342  * to call ext4_handle_dirty_metadata() instead.
1343  */
1344 static void ext4_journalled_zero_new_buffers(handle_t *handle,
1345                                             struct page *page,
1346                                             unsigned from, unsigned to)
1347 {
1348         unsigned int block_start = 0, block_end;
1349         struct buffer_head *head, *bh;
1350
1351         bh = head = page_buffers(page);
1352         do {
1353                 block_end = block_start + bh->b_size;
1354                 if (buffer_new(bh)) {
1355                         if (block_end > from && block_start < to) {
1356                                 if (!PageUptodate(page)) {
1357                                         unsigned start, size;
1358
1359                                         start = max(from, block_start);
1360                                         size = min(to, block_end) - start;
1361
1362                                         zero_user(page, start, size);
1363                                         write_end_fn(handle, bh);
1364                                 }
1365                                 clear_buffer_new(bh);
1366                         }
1367                 }
1368                 block_start = block_end;
1369                 bh = bh->b_this_page;
1370         } while (bh != head);
1371 }
1372
1373 static int ext4_journalled_write_end(struct file *file,
1374                                      struct address_space *mapping,
1375                                      loff_t pos, unsigned len, unsigned copied,
1376                                      struct page *page, void *fsdata)
1377 {
1378         handle_t *handle = ext4_journal_current_handle();
1379         struct inode *inode = mapping->host;
1380         loff_t old_size = inode->i_size;
1381         int ret = 0, ret2;
1382         int partial = 0;
1383         unsigned from, to;
1384         int size_changed = 0;
1385         int inline_data = ext4_has_inline_data(inode);
1386         bool verity = ext4_verity_in_progress(inode);
1387
1388         trace_ext4_journalled_write_end(inode, pos, len, copied);
1389         from = pos & (PAGE_SIZE - 1);
1390         to = from + len;
1391
1392         BUG_ON(!ext4_handle_valid(handle));
1393
1394         if (inline_data) {
1395                 ret = ext4_write_inline_data_end(inode, pos, len,
1396                                                  copied, page);
1397                 if (ret < 0) {
1398                         unlock_page(page);
1399                         put_page(page);
1400                         goto errout;
1401                 }
1402                 copied = ret;
1403         } else if (unlikely(copied < len) && !PageUptodate(page)) {
1404                 copied = 0;
1405                 ext4_journalled_zero_new_buffers(handle, page, from, to);
1406         } else {
1407                 if (unlikely(copied < len))
1408                         ext4_journalled_zero_new_buffers(handle, page,
1409                                                          from + copied, to);
1410                 ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
1411                                              from + copied, &partial,
1412                                              write_end_fn);
1413                 if (!partial)
1414                         SetPageUptodate(page);
1415         }
1416         if (!verity)
1417                 size_changed = ext4_update_inode_size(inode, pos + copied);
1418         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1419         EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1420         unlock_page(page);
1421         put_page(page);
1422
1423         if (old_size < pos && !verity)
1424                 pagecache_isize_extended(inode, old_size, pos);
1425
1426         if (size_changed || inline_data) {
1427                 ret2 = ext4_mark_inode_dirty(handle, inode);
1428                 if (!ret)
1429                         ret = ret2;
1430         }
1431
1432         if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1433                 /* if we have allocated more blocks and copied
1434                  * less. We will have blocks allocated outside
1435                  * inode->i_size. So truncate them
1436                  */
1437                 ext4_orphan_add(handle, inode);
1438
1439 errout:
1440         ret2 = ext4_journal_stop(handle);
1441         if (!ret)
1442                 ret = ret2;
1443         if (pos + len > inode->i_size && !verity) {
1444                 ext4_truncate_failed_write(inode);
1445                 /*
1446                  * If truncate failed early the inode might still be
1447                  * on the orphan list; we need to make sure the inode
1448                  * is removed from the orphan list in that case.
1449                  */
1450                 if (inode->i_nlink)
1451                         ext4_orphan_del(NULL, inode);
1452         }
1453
1454         return ret ? ret : copied;
1455 }
1456
1457 /*
1458  * Reserve space for a single cluster
1459  */
1460 static int ext4_da_reserve_space(struct inode *inode)
1461 {
1462         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1463         struct ext4_inode_info *ei = EXT4_I(inode);
1464         int ret;
1465
1466         /*
1467          * We will charge metadata quota at writeout time; this saves
1468          * us from metadata over-estimation, though we may go over by
1469          * a small amount in the end.  Here we just reserve for data.
1470          */
1471         ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1472         if (ret)
1473                 return ret;
1474
1475         spin_lock(&ei->i_block_reservation_lock);
1476         if (ext4_claim_free_clusters(sbi, 1, 0)) {
1477                 spin_unlock(&ei->i_block_reservation_lock);
1478                 dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1479                 return -ENOSPC;
1480         }
1481         ei->i_reserved_data_blocks++;
1482         trace_ext4_da_reserve_space(inode);
1483         spin_unlock(&ei->i_block_reservation_lock);
1484
1485         return 0;       /* success */
1486 }
1487
1488 void ext4_da_release_space(struct inode *inode, int to_free)
1489 {
1490         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1491         struct ext4_inode_info *ei = EXT4_I(inode);
1492
1493         if (!to_free)
1494                 return;         /* Nothing to release, exit */
1495
1496         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1497
1498         trace_ext4_da_release_space(inode, to_free);
1499         if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1500                 /*
1501                  * if there aren't enough reserved blocks, then the
1502                  * counter is messed up somewhere.  Since this
1503                  * function is called from invalidate page, it's
1504                  * harmless to return without any action.
1505                  */
1506                 ext4_warning(inode->i_sb, "ext4_da_release_space: "
1507                          "ino %lu, to_free %d with only %d reserved "
1508                          "data blocks", inode->i_ino, to_free,
1509                          ei->i_reserved_data_blocks);
1510                 WARN_ON(1);
1511                 to_free = ei->i_reserved_data_blocks;
1512         }
1513         ei->i_reserved_data_blocks -= to_free;
1514
1515         /* update fs dirty data blocks counter */
1516         percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1517
1518         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1519
1520         dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1521 }
1522
1523 /*
1524  * Delayed allocation stuff
1525  */
1526
1527 struct mpage_da_data {
1528         struct inode *inode;
1529         struct writeback_control *wbc;
1530
1531         pgoff_t first_page;     /* The first page to write */
1532         pgoff_t next_page;      /* Current page to examine */
1533         pgoff_t last_page;      /* Last page to examine */
1534         /*
1535          * Extent to map - this can be after first_page because that can be
1536          * fully mapped. We somewhat abuse m_flags to store whether the extent
1537          * is delalloc or unwritten.
1538          */
1539         struct ext4_map_blocks map;
1540         struct ext4_io_submit io_submit;        /* IO submission data */
1541         unsigned int do_map:1;
1542         unsigned int scanned_until_end:1;
1543 };
1544
1545 static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1546                                        bool invalidate)
1547 {
1548         int nr_pages, i;
1549         pgoff_t index, end;
1550         struct pagevec pvec;
1551         struct inode *inode = mpd->inode;
1552         struct address_space *mapping = inode->i_mapping;
1553
1554         /* This is necessary when next_page == 0. */
1555         if (mpd->first_page >= mpd->next_page)
1556                 return;
1557
1558         mpd->scanned_until_end = 0;
1559         index = mpd->first_page;
1560         end   = mpd->next_page - 1;
1561         if (invalidate) {
1562                 ext4_lblk_t start, last;
1563                 start = index << (PAGE_SHIFT - inode->i_blkbits);
1564                 last = end << (PAGE_SHIFT - inode->i_blkbits);
1565                 ext4_es_remove_extent(inode, start, last - start + 1);
1566         }
1567
1568         pagevec_init(&pvec);
1569         while (index <= end) {
1570                 nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end);
1571                 if (nr_pages == 0)
1572                         break;
1573                 for (i = 0; i < nr_pages; i++) {
1574                         struct page *page = pvec.pages[i];
1575
1576                         BUG_ON(!PageLocked(page));
1577                         BUG_ON(PageWriteback(page));
1578                         if (invalidate) {
1579                                 if (page_mapped(page))
1580                                         clear_page_dirty_for_io(page);
1581                                 block_invalidatepage(page, 0, PAGE_SIZE);
1582                                 ClearPageUptodate(page);
1583                         }
1584                         unlock_page(page);
1585                 }
1586                 pagevec_release(&pvec);
1587         }
1588 }
1589
1590 static void ext4_print_free_blocks(struct inode *inode)
1591 {
1592         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1593         struct super_block *sb = inode->i_sb;
1594         struct ext4_inode_info *ei = EXT4_I(inode);
1595
1596         ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1597                EXT4_C2B(EXT4_SB(inode->i_sb),
1598                         ext4_count_free_clusters(sb)));
1599         ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1600         ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1601                (long long) EXT4_C2B(EXT4_SB(sb),
1602                 percpu_counter_sum(&sbi->s_freeclusters_counter)));
1603         ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1604                (long long) EXT4_C2B(EXT4_SB(sb),
1605                 percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1606         ext4_msg(sb, KERN_CRIT, "Block reservation details");
1607         ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1608                  ei->i_reserved_data_blocks);
1609         return;
1610 }
1611
1612 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1613 {
1614         return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1615 }
1616
1617 /*
1618  * ext4_insert_delayed_block - adds a delayed block to the extents status
1619  *                             tree, incrementing the reserved cluster/block
1620  *                             count or making a pending reservation
1621  *                             where needed
1622  *
1623  * @inode - file containing the newly added block
1624  * @lblk - logical block to be added
1625  *
1626  * Returns 0 on success, negative error code on failure.
1627  */
1628 static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
1629 {
1630         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1631         int ret;
1632         bool allocated = false;
1633
1634         /*
1635          * If the cluster containing lblk is shared with a delayed,
1636          * written, or unwritten extent in a bigalloc file system, it's
1637          * already been accounted for and does not need to be reserved.
1638          * A pending reservation must be made for the cluster if it's
1639          * shared with a written or unwritten extent and doesn't already
1640          * have one.  Written and unwritten extents can be purged from the
1641          * extents status tree if the system is under memory pressure, so
1642          * it's necessary to examine the extent tree if a search of the
1643          * extents status tree doesn't get a match.
1644          */
1645         if (sbi->s_cluster_ratio == 1) {
1646                 ret = ext4_da_reserve_space(inode);
1647                 if (ret != 0)   /* ENOSPC */
1648                         goto errout;
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                                 } else {
1662                                         allocated = true;
1663                                 }
1664                         } else {
1665                                 allocated = true;
1666                         }
1667                 }
1668         }
1669
1670         ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
1671
1672 errout:
1673         return ret;
1674 }
1675
1676 /*
1677  * This function is grabs code from the very beginning of
1678  * ext4_map_blocks, but assumes that the caller is from delayed write
1679  * time. This function looks up the requested blocks and sets the
1680  * buffer delay bit under the protection of i_data_sem.
1681  */
1682 static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1683                               struct ext4_map_blocks *map,
1684                               struct buffer_head *bh)
1685 {
1686         struct extent_status es;
1687         int retval;
1688         sector_t invalid_block = ~((sector_t) 0xffff);
1689 #ifdef ES_AGGRESSIVE_TEST
1690         struct ext4_map_blocks orig_map;
1691
1692         memcpy(&orig_map, map, sizeof(*map));
1693 #endif
1694
1695         if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1696                 invalid_block = ~0;
1697
1698         map->m_flags = 0;
1699         ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1700                   (unsigned long) map->m_lblk);
1701
1702         /* Lookup extent status tree firstly */
1703         if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
1704                 if (ext4_es_is_hole(&es)) {
1705                         retval = 0;
1706                         down_read(&EXT4_I(inode)->i_data_sem);
1707                         goto add_delayed;
1708                 }
1709
1710                 /*
1711                  * Delayed extent could be allocated by fallocate.
1712                  * So we need to check it.
1713                  */
1714                 if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1715                         map_bh(bh, inode->i_sb, invalid_block);
1716                         set_buffer_new(bh);
1717                         set_buffer_delay(bh);
1718                         return 0;
1719                 }
1720
1721                 map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1722                 retval = es.es_len - (iblock - es.es_lblk);
1723                 if (retval > map->m_len)
1724                         retval = map->m_len;
1725                 map->m_len = retval;
1726                 if (ext4_es_is_written(&es))
1727                         map->m_flags |= EXT4_MAP_MAPPED;
1728                 else if (ext4_es_is_unwritten(&es))
1729                         map->m_flags |= EXT4_MAP_UNWRITTEN;
1730                 else
1731                         BUG();
1732
1733 #ifdef ES_AGGRESSIVE_TEST
1734                 ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1735 #endif
1736                 return retval;
1737         }
1738
1739         /*
1740          * Try to see if we can get the block without requesting a new
1741          * file system block.
1742          */
1743         down_read(&EXT4_I(inode)->i_data_sem);
1744         if (ext4_has_inline_data(inode))
1745                 retval = 0;
1746         else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1747                 retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1748         else
1749                 retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1750
1751 add_delayed:
1752         if (retval == 0) {
1753                 int ret;
1754
1755                 /*
1756                  * XXX: __block_prepare_write() unmaps passed block,
1757                  * is it OK?
1758                  */
1759
1760                 ret = ext4_insert_delayed_block(inode, map->m_lblk);
1761                 if (ret != 0) {
1762                         retval = ret;
1763                         goto out_unlock;
1764                 }
1765
1766                 map_bh(bh, inode->i_sb, invalid_block);
1767                 set_buffer_new(bh);
1768                 set_buffer_delay(bh);
1769         } else if (retval > 0) {
1770                 int ret;
1771                 unsigned int status;
1772
1773                 if (unlikely(retval != map->m_len)) {
1774                         ext4_warning(inode->i_sb,
1775                                      "ES len assertion failed for inode "
1776                                      "%lu: retval %d != map->m_len %d",
1777                                      inode->i_ino, retval, map->m_len);
1778                         WARN_ON(1);
1779                 }
1780
1781                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1782                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1783                 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1784                                             map->m_pblk, status);
1785                 if (ret != 0)
1786                         retval = ret;
1787         }
1788
1789 out_unlock:
1790         up_read((&EXT4_I(inode)->i_data_sem));
1791
1792         return retval;
1793 }
1794
1795 /*
1796  * This is a special get_block_t callback which is used by
1797  * ext4_da_write_begin().  It will either return mapped block or
1798  * reserve space for a single block.
1799  *
1800  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1801  * We also have b_blocknr = -1 and b_bdev initialized properly
1802  *
1803  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1804  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1805  * initialized properly.
1806  */
1807 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1808                            struct buffer_head *bh, int create)
1809 {
1810         struct ext4_map_blocks map;
1811         int ret = 0;
1812
1813         BUG_ON(create == 0);
1814         BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1815
1816         map.m_lblk = iblock;
1817         map.m_len = 1;
1818
1819         /*
1820          * first, we need to know whether the block is allocated already
1821          * preallocated blocks are unmapped but should treated
1822          * the same as allocated blocks.
1823          */
1824         ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1825         if (ret <= 0)
1826                 return ret;
1827
1828         map_bh(bh, inode->i_sb, map.m_pblk);
1829         ext4_update_bh_state(bh, map.m_flags);
1830
1831         if (buffer_unwritten(bh)) {
1832                 /* A delayed write to unwritten bh should be marked
1833                  * new and mapped.  Mapped ensures that we don't do
1834                  * get_block multiple times when we write to the same
1835                  * offset and new ensures that we do proper zero out
1836                  * for partial write.
1837                  */
1838                 set_buffer_new(bh);
1839                 set_buffer_mapped(bh);
1840         }
1841         return 0;
1842 }
1843
1844 static int bget_one(handle_t *handle, struct buffer_head *bh)
1845 {
1846         get_bh(bh);
1847         return 0;
1848 }
1849
1850 static int bput_one(handle_t *handle, struct buffer_head *bh)
1851 {
1852         put_bh(bh);
1853         return 0;
1854 }
1855
1856 static int __ext4_journalled_writepage(struct page *page,
1857                                        unsigned int len)
1858 {
1859         struct address_space *mapping = page->mapping;
1860         struct inode *inode = mapping->host;
1861         struct buffer_head *page_bufs = NULL;
1862         handle_t *handle = NULL;
1863         int ret = 0, err = 0;
1864         int inline_data = ext4_has_inline_data(inode);
1865         struct buffer_head *inode_bh = NULL;
1866
1867         ClearPageChecked(page);
1868
1869         if (inline_data) {
1870                 BUG_ON(page->index != 0);
1871                 BUG_ON(len > ext4_get_max_inline_size(inode));
1872                 inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1873                 if (inode_bh == NULL)
1874                         goto out;
1875         } else {
1876                 page_bufs = page_buffers(page);
1877                 if (!page_bufs) {
1878                         BUG();
1879                         goto out;
1880                 }
1881                 ext4_walk_page_buffers(handle, page_bufs, 0, len,
1882                                        NULL, bget_one);
1883         }
1884         /*
1885          * We need to release the page lock before we start the
1886          * journal, so grab a reference so the page won't disappear
1887          * out from under us.
1888          */
1889         get_page(page);
1890         unlock_page(page);
1891
1892         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1893                                     ext4_writepage_trans_blocks(inode));
1894         if (IS_ERR(handle)) {
1895                 ret = PTR_ERR(handle);
1896                 put_page(page);
1897                 goto out_no_pagelock;
1898         }
1899         BUG_ON(!ext4_handle_valid(handle));
1900
1901         lock_page(page);
1902         put_page(page);
1903         if (page->mapping != mapping) {
1904                 /* The page got truncated from under us */
1905                 ext4_journal_stop(handle);
1906                 ret = 0;
1907                 goto out;
1908         }
1909
1910         if (inline_data) {
1911                 ret = ext4_mark_inode_dirty(handle, inode);
1912         } else {
1913                 ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1914                                              do_journal_get_write_access);
1915
1916                 err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1917                                              write_end_fn);
1918         }
1919         if (ret == 0)
1920                 ret = err;
1921         err = ext4_jbd2_inode_add_write(handle, inode, page_offset(page), len);
1922         if (ret == 0)
1923                 ret = err;
1924         EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1925         err = ext4_journal_stop(handle);
1926         if (!ret)
1927                 ret = err;
1928
1929         if (!ext4_has_inline_data(inode))
1930                 ext4_walk_page_buffers(NULL, page_bufs, 0, len,
1931                                        NULL, bput_one);
1932         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1933 out:
1934         unlock_page(page);
1935 out_no_pagelock:
1936         brelse(inode_bh);
1937         return ret;
1938 }
1939
1940 /*
1941  * Note that we don't need to start a transaction unless we're journaling data
1942  * because we should have holes filled from ext4_page_mkwrite(). We even don't
1943  * need to file the inode to the transaction's list in ordered mode because if
1944  * we are writing back data added by write(), the inode is already there and if
1945  * we are writing back data modified via mmap(), no one guarantees in which
1946  * transaction the data will hit the disk. In case we are journaling data, we
1947  * cannot start transaction directly because transaction start ranks above page
1948  * lock so we have to do some magic.
1949  *
1950  * This function can get called via...
1951  *   - ext4_writepages after taking page lock (have journal handle)
1952  *   - journal_submit_inode_data_buffers (no journal handle)
1953  *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1954  *   - grab_page_cache when doing write_begin (have journal handle)
1955  *
1956  * We don't do any block allocation in this function. If we have page with
1957  * multiple blocks we need to write those buffer_heads that are mapped. This
1958  * is important for mmaped based write. So if we do with blocksize 1K
1959  * truncate(f, 1024);
1960  * a = mmap(f, 0, 4096);
1961  * a[0] = 'a';
1962  * truncate(f, 4096);
1963  * we have in the page first buffer_head mapped via page_mkwrite call back
1964  * but other buffer_heads would be unmapped but dirty (dirty done via the
1965  * do_wp_page). So writepage should write the first block. If we modify
1966  * the mmap area beyond 1024 we will again get a page_fault and the
1967  * page_mkwrite callback will do the block allocation and mark the
1968  * buffer_heads mapped.
1969  *
1970  * We redirty the page if we have any buffer_heads that is either delay or
1971  * unwritten in the page.
1972  *
1973  * We can get recursively called as show below.
1974  *
1975  *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1976  *              ext4_writepage()
1977  *
1978  * But since we don't do any block allocation we should not deadlock.
1979  * Page also have the dirty flag cleared so we don't get recurive page_lock.
1980  */
1981 static int ext4_writepage(struct page *page,
1982                           struct writeback_control *wbc)
1983 {
1984         int ret = 0;
1985         loff_t size;
1986         unsigned int len;
1987         struct buffer_head *page_bufs = NULL;
1988         struct inode *inode = page->mapping->host;
1989         struct ext4_io_submit io_submit;
1990         bool keep_towrite = false;
1991
1992         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
1993                 inode->i_mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
1994                 unlock_page(page);
1995                 return -EIO;
1996         }
1997
1998         trace_ext4_writepage(page);
1999         size = i_size_read(inode);
2000         if (page->index == size >> PAGE_SHIFT &&
2001             !ext4_verity_in_progress(inode))
2002                 len = size & ~PAGE_MASK;
2003         else
2004                 len = PAGE_SIZE;
2005
2006         page_bufs = page_buffers(page);
2007         /*
2008          * We cannot do block allocation or other extent handling in this
2009          * function. If there are buffers needing that, we have to redirty
2010          * the page. But we may reach here when we do a journal commit via
2011          * journal_submit_inode_data_buffers() and in that case we must write
2012          * allocated buffers to achieve data=ordered mode guarantees.
2013          *
2014          * Also, if there is only one buffer per page (the fs block
2015          * size == the page size), if one buffer needs block
2016          * allocation or needs to modify the extent tree to clear the
2017          * unwritten flag, we know that the page can't be written at
2018          * all, so we might as well refuse the write immediately.
2019          * Unfortunately if the block size != page size, we can't as
2020          * easily detect this case using ext4_walk_page_buffers(), but
2021          * for the extremely common case, this is an optimization that
2022          * skips a useless round trip through ext4_bio_write_page().
2023          */
2024         if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2025                                    ext4_bh_delay_or_unwritten)) {
2026                 redirty_page_for_writepage(wbc, page);
2027                 if ((current->flags & PF_MEMALLOC) ||
2028                     (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2029                         /*
2030                          * For memory cleaning there's no point in writing only
2031                          * some buffers. So just bail out. Warn if we came here
2032                          * from direct reclaim.
2033                          */
2034                         WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2035                                                         == PF_MEMALLOC);
2036                         unlock_page(page);
2037                         return 0;
2038                 }
2039                 keep_towrite = true;
2040         }
2041
2042         if (PageChecked(page) && ext4_should_journal_data(inode))
2043                 /*
2044                  * It's mmapped pagecache.  Add buffers and journal it.  There
2045                  * doesn't seem much point in redirtying the page here.
2046                  */
2047                 return __ext4_journalled_writepage(page, len);
2048
2049         ext4_io_submit_init(&io_submit, wbc);
2050         io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2051         if (!io_submit.io_end) {
2052                 redirty_page_for_writepage(wbc, page);
2053                 unlock_page(page);
2054                 return -ENOMEM;
2055         }
2056         ret = ext4_bio_write_page(&io_submit, page, len, wbc, keep_towrite);
2057         ext4_io_submit(&io_submit);
2058         /* Drop io_end reference we got from init */
2059         ext4_put_io_end_defer(io_submit.io_end);
2060         return ret;
2061 }
2062
2063 static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2064 {
2065         int len;
2066         loff_t size;
2067         int err;
2068
2069         BUG_ON(page->index != mpd->first_page);
2070         clear_page_dirty_for_io(page);
2071         /*
2072          * We have to be very careful here!  Nothing protects writeback path
2073          * against i_size changes and the page can be writeably mapped into
2074          * page tables. So an application can be growing i_size and writing
2075          * data through mmap while writeback runs. clear_page_dirty_for_io()
2076          * write-protects our page in page tables and the page cannot get
2077          * written to again until we release page lock. So only after
2078          * clear_page_dirty_for_io() we are safe to sample i_size for
2079          * ext4_bio_write_page() to zero-out tail of the written page. We rely
2080          * on the barrier provided by TestClearPageDirty in
2081          * clear_page_dirty_for_io() to make sure i_size is really sampled only
2082          * after page tables are updated.
2083          */
2084         size = i_size_read(mpd->inode);
2085         if (page->index == size >> PAGE_SHIFT &&
2086             !ext4_verity_in_progress(mpd->inode))
2087                 len = size & ~PAGE_MASK;
2088         else
2089                 len = PAGE_SIZE;
2090         err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false);
2091         if (!err)
2092                 mpd->wbc->nr_to_write--;
2093         mpd->first_page++;
2094
2095         return err;
2096 }
2097
2098 #define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
2099
2100 /*
2101  * mballoc gives us at most this number of blocks...
2102  * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2103  * The rest of mballoc seems to handle chunks up to full group size.
2104  */
2105 #define MAX_WRITEPAGES_EXTENT_LEN 2048
2106
2107 /*
2108  * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2109  *
2110  * @mpd - extent of blocks
2111  * @lblk - logical number of the block in the file
2112  * @bh - buffer head we want to add to the extent
2113  *
2114  * The function is used to collect contig. blocks in the same state. If the
2115  * buffer doesn't require mapping for writeback and we haven't started the
2116  * extent of buffers to map yet, the function returns 'true' immediately - the
2117  * caller can write the buffer right away. Otherwise the function returns true
2118  * if the block has been added to the extent, false if the block couldn't be
2119  * added.
2120  */
2121 static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2122                                    struct buffer_head *bh)
2123 {
2124         struct ext4_map_blocks *map = &mpd->map;
2125
2126         /* Buffer that doesn't need mapping for writeback? */
2127         if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2128             (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2129                 /* So far no extent to map => we write the buffer right away */
2130                 if (map->m_len == 0)
2131                         return true;
2132                 return false;
2133         }
2134
2135         /* First block in the extent? */
2136         if (map->m_len == 0) {
2137                 /* We cannot map unless handle is started... */
2138                 if (!mpd->do_map)
2139                         return false;
2140                 map->m_lblk = lblk;
2141                 map->m_len = 1;
2142                 map->m_flags = bh->b_state & BH_FLAGS;
2143                 return true;
2144         }
2145
2146         /* Don't go larger than mballoc is willing to allocate */
2147         if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2148                 return false;
2149
2150         /* Can we merge the block to our big extent? */
2151         if (lblk == map->m_lblk + map->m_len &&
2152             (bh->b_state & BH_FLAGS) == map->m_flags) {
2153                 map->m_len++;
2154                 return true;
2155         }
2156         return false;
2157 }
2158
2159 /*
2160  * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2161  *
2162  * @mpd - extent of blocks for mapping
2163  * @head - the first buffer in the page
2164  * @bh - buffer we should start processing from
2165  * @lblk - logical number of the block in the file corresponding to @bh
2166  *
2167  * Walk through page buffers from @bh upto @head (exclusive) and either submit
2168  * the page for IO if all buffers in this page were mapped and there's no
2169  * accumulated extent of buffers to map or add buffers in the page to the
2170  * extent of buffers to map. The function returns 1 if the caller can continue
2171  * by processing the next page, 0 if it should stop adding buffers to the
2172  * extent to map because we cannot extend it anymore. It can also return value
2173  * < 0 in case of error during IO submission.
2174  */
2175 static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2176                                    struct buffer_head *head,
2177                                    struct buffer_head *bh,
2178                                    ext4_lblk_t lblk)
2179 {
2180         struct inode *inode = mpd->inode;
2181         int err;
2182         ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
2183                                                         >> inode->i_blkbits;
2184
2185         if (ext4_verity_in_progress(inode))
2186                 blocks = EXT_MAX_BLOCKS;
2187
2188         do {
2189                 BUG_ON(buffer_locked(bh));
2190
2191                 if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2192                         /* Found extent to map? */
2193                         if (mpd->map.m_len)
2194                                 return 0;
2195                         /* Buffer needs mapping and handle is not started? */
2196                         if (!mpd->do_map)
2197                                 return 0;
2198                         /* Everything mapped so far and we hit EOF */
2199                         break;
2200                 }
2201         } while (lblk++, (bh = bh->b_this_page) != head);
2202         /* So far everything mapped? Submit the page for IO. */
2203         if (mpd->map.m_len == 0) {
2204                 err = mpage_submit_page(mpd, head->b_page);
2205                 if (err < 0)
2206                         return err;
2207         }
2208         if (lblk >= blocks) {
2209                 mpd->scanned_until_end = 1;
2210                 return 0;
2211         }
2212         return 1;
2213 }
2214
2215 /*
2216  * mpage_process_page - update page buffers corresponding to changed extent and
2217  *                     may submit fully mapped page for IO
2218  *
2219  * @mpd         - description of extent to map, on return next extent to map
2220  * @m_lblk      - logical block mapping.
2221  * @m_pblk      - corresponding physical mapping.
2222  * @map_bh      - determines on return whether this page requires any further
2223  *                mapping or not.
2224  * Scan given page buffers corresponding to changed extent and update buffer
2225  * state according to new extent state.
2226  * We map delalloc buffers to their physical location, clear unwritten bits.
2227  * If the given page is not fully mapped, we update @map to the next extent in
2228  * the given page that needs mapping & return @map_bh as true.
2229  */
2230 static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
2231                               ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
2232                               bool *map_bh)
2233 {
2234         struct buffer_head *head, *bh;
2235         ext4_io_end_t *io_end = mpd->io_submit.io_end;
2236         ext4_lblk_t lblk = *m_lblk;
2237         ext4_fsblk_t pblock = *m_pblk;
2238         int err = 0;
2239         int blkbits = mpd->inode->i_blkbits;
2240         ssize_t io_end_size = 0;
2241         struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2242
2243         bh = head = page_buffers(page);
2244         do {
2245                 if (lblk < mpd->map.m_lblk)
2246                         continue;
2247                 if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2248                         /*
2249                          * Buffer after end of mapped extent.
2250                          * Find next buffer in the page to map.
2251                          */
2252                         mpd->map.m_len = 0;
2253                         mpd->map.m_flags = 0;
2254                         io_end_vec->size += io_end_size;
2255                         io_end_size = 0;
2256
2257                         err = mpage_process_page_bufs(mpd, head, bh, lblk);
2258                         if (err > 0)
2259                                 err = 0;
2260                         if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2261                                 io_end_vec = ext4_alloc_io_end_vec(io_end);
2262                                 if (IS_ERR(io_end_vec)) {
2263                                         err = PTR_ERR(io_end_vec);
2264                                         goto out;
2265                                 }
2266                                 io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
2267                         }
2268                         *map_bh = true;
2269                         goto out;
2270                 }
2271                 if (buffer_delay(bh)) {
2272                         clear_buffer_delay(bh);
2273                         bh->b_blocknr = pblock++;
2274                 }
2275                 clear_buffer_unwritten(bh);
2276                 io_end_size += (1 << blkbits);
2277         } while (lblk++, (bh = bh->b_this_page) != head);
2278
2279         io_end_vec->size += io_end_size;
2280         io_end_size = 0;
2281         *map_bh = false;
2282 out:
2283         *m_lblk = lblk;
2284         *m_pblk = pblock;
2285         return err;
2286 }
2287
2288 /*
2289  * mpage_map_buffers - update buffers corresponding to changed extent and
2290  *                     submit fully mapped pages for IO
2291  *
2292  * @mpd - description of extent to map, on return next extent to map
2293  *
2294  * Scan buffers corresponding to changed extent (we expect corresponding pages
2295  * to be already locked) and update buffer state according to new extent state.
2296  * We map delalloc buffers to their physical location, clear unwritten bits,
2297  * and mark buffers as uninit when we perform writes to unwritten extents
2298  * and do extent conversion after IO is finished. If the last page is not fully
2299  * mapped, we update @map to the next extent in the last page that needs
2300  * mapping. Otherwise we submit the page for IO.
2301  */
2302 static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2303 {
2304         struct pagevec pvec;
2305         int nr_pages, i;
2306         struct inode *inode = mpd->inode;
2307         int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2308         pgoff_t start, end;
2309         ext4_lblk_t lblk;
2310         ext4_fsblk_t pblock;
2311         int err;
2312         bool map_bh = false;
2313
2314         start = mpd->map.m_lblk >> bpp_bits;
2315         end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2316         lblk = start << bpp_bits;
2317         pblock = mpd->map.m_pblk;
2318
2319         pagevec_init(&pvec);
2320         while (start <= end) {
2321                 nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
2322                                                 &start, end);
2323                 if (nr_pages == 0)
2324                         break;
2325                 for (i = 0; i < nr_pages; i++) {
2326                         struct page *page = pvec.pages[i];
2327
2328                         err = mpage_process_page(mpd, page, &lblk, &pblock,
2329                                                  &map_bh);
2330                         /*
2331                          * If map_bh is true, means page may require further bh
2332                          * mapping, or maybe the page was submitted for IO.
2333                          * So we return to call further extent mapping.
2334                          */
2335                         if (err < 0 || map_bh)
2336                                 goto out;
2337                         /* Page fully mapped - let IO run! */
2338                         err = mpage_submit_page(mpd, page);
2339                         if (err < 0)
2340                                 goto out;
2341                 }
2342                 pagevec_release(&pvec);
2343         }
2344         /* Extent fully mapped and matches with page boundary. We are done. */
2345         mpd->map.m_len = 0;
2346         mpd->map.m_flags = 0;
2347         return 0;
2348 out:
2349         pagevec_release(&pvec);
2350         return err;
2351 }
2352
2353 static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2354 {
2355         struct inode *inode = mpd->inode;
2356         struct ext4_map_blocks *map = &mpd->map;
2357         int get_blocks_flags;
2358         int err, dioread_nolock;
2359
2360         trace_ext4_da_write_pages_extent(inode, map);
2361         /*
2362          * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2363          * to convert an unwritten extent to be initialized (in the case
2364          * where we have written into one or more preallocated blocks).  It is
2365          * possible that we're going to need more metadata blocks than
2366          * previously reserved. However we must not fail because we're in
2367          * writeback and there is nothing we can do about it so it might result
2368          * in data loss.  So use reserved blocks to allocate metadata if
2369          * possible.
2370          *
2371          * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2372          * the blocks in question are delalloc blocks.  This indicates
2373          * that the blocks and quotas has already been checked when
2374          * the data was copied into the page cache.
2375          */
2376         get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2377                            EXT4_GET_BLOCKS_METADATA_NOFAIL |
2378                            EXT4_GET_BLOCKS_IO_SUBMIT;
2379         dioread_nolock = ext4_should_dioread_nolock(inode);
2380         if (dioread_nolock)
2381                 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2382         if (map->m_flags & BIT(BH_Delay))
2383                 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2384
2385         err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2386         if (err < 0)
2387                 return err;
2388         if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2389                 if (!mpd->io_submit.io_end->handle &&
2390                     ext4_handle_valid(handle)) {
2391                         mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2392                         handle->h_rsv_handle = NULL;
2393                 }
2394                 ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2395         }
2396
2397         BUG_ON(map->m_len == 0);
2398         return 0;
2399 }
2400
2401 /*
2402  * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2403  *                               mpd->len and submit pages underlying it for IO
2404  *
2405  * @handle - handle for journal operations
2406  * @mpd - extent to map
2407  * @give_up_on_write - we set this to true iff there is a fatal error and there
2408  *                     is no hope of writing the data. The caller should discard
2409  *                     dirty pages to avoid infinite loops.
2410  *
2411  * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2412  * delayed, blocks are allocated, if it is unwritten, we may need to convert
2413  * them to initialized or split the described range from larger unwritten
2414  * extent. Note that we need not map all the described range since allocation
2415  * can return less blocks or the range is covered by more unwritten extents. We
2416  * cannot map more because we are limited by reserved transaction credits. On
2417  * the other hand we always make sure that the last touched page is fully
2418  * mapped so that it can be written out (and thus forward progress is
2419  * guaranteed). After mapping we submit all mapped pages for IO.
2420  */
2421 static int mpage_map_and_submit_extent(handle_t *handle,
2422                                        struct mpage_da_data *mpd,
2423                                        bool *give_up_on_write)
2424 {
2425         struct inode *inode = mpd->inode;
2426         struct ext4_map_blocks *map = &mpd->map;
2427         int err;
2428         loff_t disksize;
2429         int progress = 0;
2430         ext4_io_end_t *io_end = mpd->io_submit.io_end;
2431         struct ext4_io_end_vec *io_end_vec;
2432
2433         io_end_vec = ext4_alloc_io_end_vec(io_end);
2434         if (IS_ERR(io_end_vec))
2435                 return PTR_ERR(io_end_vec);
2436         io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2437         do {
2438                 err = mpage_map_one_extent(handle, mpd);
2439                 if (err < 0) {
2440                         struct super_block *sb = inode->i_sb;
2441
2442                         if (ext4_forced_shutdown(EXT4_SB(sb)) ||
2443                             EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
2444                                 goto invalidate_dirty_pages;
2445                         /*
2446                          * Let the uper layers retry transient errors.
2447                          * In the case of ENOSPC, if ext4_count_free_blocks()
2448                          * is non-zero, a commit should free up blocks.
2449                          */
2450                         if ((err == -ENOMEM) ||
2451                             (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2452                                 if (progress)
2453                                         goto update_disksize;
2454                                 return err;
2455                         }
2456                         ext4_msg(sb, KERN_CRIT,
2457                                  "Delayed block allocation failed for "
2458                                  "inode %lu at logical offset %llu with"
2459                                  " max blocks %u with error %d",
2460                                  inode->i_ino,
2461                                  (unsigned long long)map->m_lblk,
2462                                  (unsigned)map->m_len, -err);
2463                         ext4_msg(sb, KERN_CRIT,
2464                                  "This should not happen!! Data will "
2465                                  "be lost\n");
2466                         if (err == -ENOSPC)
2467                                 ext4_print_free_blocks(inode);
2468                 invalidate_dirty_pages:
2469                         *give_up_on_write = true;
2470                         return err;
2471                 }
2472                 progress = 1;
2473                 /*
2474                  * Update buffer state, submit mapped pages, and get us new
2475                  * extent to map
2476                  */
2477                 err = mpage_map_and_submit_buffers(mpd);
2478                 if (err < 0)
2479                         goto update_disksize;
2480         } while (map->m_len);
2481
2482 update_disksize:
2483         /*
2484          * Update on-disk size after IO is submitted.  Races with
2485          * truncate are avoided by checking i_size under i_data_sem.
2486          */
2487         disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2488         if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2489                 int err2;
2490                 loff_t i_size;
2491
2492                 down_write(&EXT4_I(inode)->i_data_sem);
2493                 i_size = i_size_read(inode);
2494                 if (disksize > i_size)
2495                         disksize = i_size;
2496                 if (disksize > EXT4_I(inode)->i_disksize)
2497                         EXT4_I(inode)->i_disksize = disksize;
2498                 up_write(&EXT4_I(inode)->i_data_sem);
2499                 err2 = ext4_mark_inode_dirty(handle, inode);
2500                 if (err2) {
2501                         ext4_error_err(inode->i_sb, -err2,
2502                                        "Failed to mark inode %lu dirty",
2503                                        inode->i_ino);
2504                 }
2505                 if (!err)
2506                         err = err2;
2507         }
2508         return err;
2509 }
2510
2511 /*
2512  * Calculate the total number of credits to reserve for one writepages
2513  * iteration. This is called from ext4_writepages(). We map an extent of
2514  * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2515  * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2516  * bpp - 1 blocks in bpp different extents.
2517  */
2518 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2519 {
2520         int bpp = ext4_journal_blocks_per_page(inode);
2521
2522         return ext4_meta_trans_blocks(inode,
2523                                 MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2524 }
2525
2526 /*
2527  * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2528  *                               and underlying extent to map
2529  *
2530  * @mpd - where to look for pages
2531  *
2532  * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2533  * IO immediately. When we find a page which isn't mapped we start accumulating
2534  * extent of buffers underlying these pages that needs mapping (formed by
2535  * either delayed or unwritten buffers). We also lock the pages containing
2536  * these buffers. The extent found is returned in @mpd structure (starting at
2537  * mpd->lblk with length mpd->len blocks).
2538  *
2539  * Note that this function can attach bios to one io_end structure which are
2540  * neither logically nor physically contiguous. Although it may seem as an
2541  * unnecessary complication, it is actually inevitable in blocksize < pagesize
2542  * case as we need to track IO to all buffers underlying a page in one io_end.
2543  */
2544 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2545 {
2546         struct address_space *mapping = mpd->inode->i_mapping;
2547         struct pagevec pvec;
2548         unsigned int nr_pages;
2549         long left = mpd->wbc->nr_to_write;
2550         pgoff_t index = mpd->first_page;
2551         pgoff_t end = mpd->last_page;
2552         xa_mark_t tag;
2553         int i, err = 0;
2554         int blkbits = mpd->inode->i_blkbits;
2555         ext4_lblk_t lblk;
2556         struct buffer_head *head;
2557
2558         if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2559                 tag = PAGECACHE_TAG_TOWRITE;
2560         else
2561                 tag = PAGECACHE_TAG_DIRTY;
2562
2563         pagevec_init(&pvec);
2564         mpd->map.m_len = 0;
2565         mpd->next_page = index;
2566         while (index <= end) {
2567                 nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
2568                                 tag);
2569                 if (nr_pages == 0)
2570                         break;
2571
2572                 for (i = 0; i < nr_pages; i++) {
2573                         struct page *page = pvec.pages[i];
2574
2575                         /*
2576                          * Accumulated enough dirty pages? This doesn't apply
2577                          * to WB_SYNC_ALL mode. For integrity sync we have to
2578                          * keep going because someone may be concurrently
2579                          * dirtying pages, and we might have synced a lot of
2580                          * newly appeared dirty pages, but have not synced all
2581                          * of the old dirty pages.
2582                          */
2583                         if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2584                                 goto out;
2585
2586                         /* If we can't merge this page, we are done. */
2587                         if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2588                                 goto out;
2589
2590                         lock_page(page);
2591                         /*
2592                          * If the page is no longer dirty, or its mapping no
2593                          * longer corresponds to inode we are writing (which
2594                          * means it has been truncated or invalidated), or the
2595                          * page is already under writeback and we are not doing
2596                          * a data integrity writeback, skip the page
2597                          */
2598                         if (!PageDirty(page) ||
2599                             (PageWriteback(page) &&
2600                              (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2601                             unlikely(page->mapping != mapping)) {
2602                                 unlock_page(page);
2603                                 continue;
2604                         }
2605
2606                         wait_on_page_writeback(page);
2607                         BUG_ON(PageWriteback(page));
2608
2609                         if (mpd->map.m_len == 0)
2610                                 mpd->first_page = page->index;
2611                         mpd->next_page = page->index + 1;
2612                         /* Add all dirty buffers to mpd */
2613                         lblk = ((ext4_lblk_t)page->index) <<
2614                                 (PAGE_SHIFT - blkbits);
2615                         head = page_buffers(page);
2616                         err = mpage_process_page_bufs(mpd, head, head, lblk);
2617                         if (err <= 0)
2618                                 goto out;
2619                         err = 0;
2620                         left--;
2621                 }
2622                 pagevec_release(&pvec);
2623                 cond_resched();
2624         }
2625         mpd->scanned_until_end = 1;
2626         return 0;
2627 out:
2628         pagevec_release(&pvec);
2629         return err;
2630 }
2631
2632 static int ext4_writepages(struct address_space *mapping,
2633                            struct writeback_control *wbc)
2634 {
2635         pgoff_t writeback_index = 0;
2636         long nr_to_write = wbc->nr_to_write;
2637         int range_whole = 0;
2638         int cycled = 1;
2639         handle_t *handle = NULL;
2640         struct mpage_da_data mpd;
2641         struct inode *inode = mapping->host;
2642         int needed_blocks, rsv_blocks = 0, ret = 0;
2643         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2644         struct blk_plug plug;
2645         bool give_up_on_write = false;
2646
2647         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2648                 return -EIO;
2649
2650         percpu_down_read(&sbi->s_writepages_rwsem);
2651         trace_ext4_writepages(inode, wbc);
2652
2653         /*
2654          * No pages to write? This is mainly a kludge to avoid starting
2655          * a transaction for special inodes like journal inode on last iput()
2656          * because that could violate lock ordering on umount
2657          */
2658         if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2659                 goto out_writepages;
2660
2661         if (ext4_should_journal_data(inode)) {
2662                 ret = generic_writepages(mapping, wbc);
2663                 goto out_writepages;
2664         }
2665
2666         /*
2667          * If the filesystem has aborted, it is read-only, so return
2668          * right away instead of dumping stack traces later on that
2669          * will obscure the real source of the problem.  We test
2670          * EXT4_MF_FS_ABORTED instead of sb->s_flag's SB_RDONLY because
2671          * the latter could be true if the filesystem is mounted
2672          * read-only, and in that case, ext4_writepages should
2673          * *never* be called, so if that ever happens, we would want
2674          * the stack trace.
2675          */
2676         if (unlikely(ext4_forced_shutdown(EXT4_SB(mapping->host->i_sb)) ||
2677                      sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) {
2678                 ret = -EROFS;
2679                 goto out_writepages;
2680         }
2681
2682         /*
2683          * If we have inline data and arrive here, it means that
2684          * we will soon create the block for the 1st page, so
2685          * we'd better clear the inline data here.
2686          */
2687         if (ext4_has_inline_data(inode)) {
2688                 /* Just inode will be modified... */
2689                 handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2690                 if (IS_ERR(handle)) {
2691                         ret = PTR_ERR(handle);
2692                         goto out_writepages;
2693                 }
2694                 BUG_ON(ext4_test_inode_state(inode,
2695                                 EXT4_STATE_MAY_INLINE_DATA));
2696                 ext4_destroy_inline_data(handle, inode);
2697                 ext4_journal_stop(handle);
2698         }
2699
2700         if (ext4_should_dioread_nolock(inode)) {
2701                 /*
2702                  * We may need to convert up to one extent per block in
2703                  * the page and we may dirty the inode.
2704                  */
2705                 rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
2706                                                 PAGE_SIZE >> inode->i_blkbits);
2707         }
2708
2709         if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2710                 range_whole = 1;
2711
2712         if (wbc->range_cyclic) {
2713                 writeback_index = mapping->writeback_index;
2714                 if (writeback_index)
2715                         cycled = 0;
2716                 mpd.first_page = writeback_index;
2717                 mpd.last_page = -1;
2718         } else {
2719                 mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2720                 mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2721         }
2722
2723         mpd.inode = inode;
2724         mpd.wbc = wbc;
2725         ext4_io_submit_init(&mpd.io_submit, wbc);
2726 retry:
2727         if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2728                 tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2729         blk_start_plug(&plug);
2730
2731         /*
2732          * First writeback pages that don't need mapping - we can avoid
2733          * starting a transaction unnecessarily and also avoid being blocked
2734          * in the block layer on device congestion while having transaction
2735          * started.
2736          */
2737         mpd.do_map = 0;
2738         mpd.scanned_until_end = 0;
2739         mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2740         if (!mpd.io_submit.io_end) {
2741                 ret = -ENOMEM;
2742                 goto unplug;
2743         }
2744         ret = mpage_prepare_extent_to_map(&mpd);
2745         /* Unlock pages we didn't use */
2746         mpage_release_unused_pages(&mpd, false);
2747         /* Submit prepared bio */
2748         ext4_io_submit(&mpd.io_submit);
2749         ext4_put_io_end_defer(mpd.io_submit.io_end);
2750         mpd.io_submit.io_end = NULL;
2751         if (ret < 0)
2752                 goto unplug;
2753
2754         while (!mpd.scanned_until_end && wbc->nr_to_write > 0) {
2755                 /* For each extent of pages we use new io_end */
2756                 mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2757                 if (!mpd.io_submit.io_end) {
2758                         ret = -ENOMEM;
2759                         break;
2760                 }
2761
2762                 /*
2763                  * We have two constraints: We find one extent to map and we
2764                  * must always write out whole page (makes a difference when
2765                  * blocksize < pagesize) so that we don't block on IO when we
2766                  * try to write out the rest of the page. Journalled mode is
2767                  * not supported by delalloc.
2768                  */
2769                 BUG_ON(ext4_should_journal_data(inode));
2770                 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2771
2772                 /* start a new transaction */
2773                 handle = ext4_journal_start_with_reserve(inode,
2774                                 EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2775                 if (IS_ERR(handle)) {
2776                         ret = PTR_ERR(handle);
2777                         ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2778                                "%ld pages, ino %lu; err %d", __func__,
2779                                 wbc->nr_to_write, inode->i_ino, ret);
2780                         /* Release allocated io_end */
2781                         ext4_put_io_end(mpd.io_submit.io_end);
2782                         mpd.io_submit.io_end = NULL;
2783                         break;
2784                 }
2785                 mpd.do_map = 1;
2786
2787                 trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2788                 ret = mpage_prepare_extent_to_map(&mpd);
2789                 if (!ret && mpd.map.m_len)
2790                         ret = mpage_map_and_submit_extent(handle, &mpd,
2791                                         &give_up_on_write);
2792                 /*
2793                  * Caution: If the handle is synchronous,
2794                  * ext4_journal_stop() can wait for transaction commit
2795                  * to finish which may depend on writeback of pages to
2796                  * complete or on page lock to be released.  In that
2797                  * case, we have to wait until after we have
2798                  * submitted all the IO, released page locks we hold,
2799                  * and dropped io_end reference (for extent conversion
2800                  * to be able to complete) before stopping the handle.
2801                  */
2802                 if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2803                         ext4_journal_stop(handle);
2804                         handle = NULL;
2805                         mpd.do_map = 0;
2806                 }
2807                 /* Unlock pages we didn't use */
2808                 mpage_release_unused_pages(&mpd, give_up_on_write);
2809                 /* Submit prepared bio */
2810                 ext4_io_submit(&mpd.io_submit);
2811
2812                 /*
2813                  * Drop our io_end reference we got from init. We have
2814                  * to be careful and use deferred io_end finishing if
2815                  * we are still holding the transaction as we can
2816                  * release the last reference to io_end which may end
2817                  * up doing unwritten extent conversion.
2818                  */
2819                 if (handle) {
2820                         ext4_put_io_end_defer(mpd.io_submit.io_end);
2821                         ext4_journal_stop(handle);
2822                 } else
2823                         ext4_put_io_end(mpd.io_submit.io_end);
2824                 mpd.io_submit.io_end = NULL;
2825
2826                 if (ret == -ENOSPC && sbi->s_journal) {
2827                         /*
2828                          * Commit the transaction which would
2829                          * free blocks released in the transaction
2830                          * and try again
2831                          */
2832                         jbd2_journal_force_commit_nested(sbi->s_journal);
2833                         ret = 0;
2834                         continue;
2835                 }
2836                 /* Fatal error - ENOMEM, EIO... */
2837                 if (ret)
2838                         break;
2839         }
2840 unplug:
2841         blk_finish_plug(&plug);
2842         if (!ret && !cycled && wbc->nr_to_write > 0) {
2843                 cycled = 1;
2844                 mpd.last_page = writeback_index - 1;
2845                 mpd.first_page = 0;
2846                 goto retry;
2847         }
2848
2849         /* Update index */
2850         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2851                 /*
2852                  * Set the writeback_index so that range_cyclic
2853                  * mode will write it back later
2854                  */
2855                 mapping->writeback_index = mpd.first_page;
2856
2857 out_writepages:
2858         trace_ext4_writepages_result(inode, wbc, ret,
2859                                      nr_to_write - wbc->nr_to_write);
2860         percpu_up_read(&sbi->s_writepages_rwsem);
2861         return ret;
2862 }
2863
2864 static int ext4_dax_writepages(struct address_space *mapping,
2865                                struct writeback_control *wbc)
2866 {
2867         int ret;
2868         long nr_to_write = wbc->nr_to_write;
2869         struct inode *inode = mapping->host;
2870         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2871
2872         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2873                 return -EIO;
2874
2875         percpu_down_read(&sbi->s_writepages_rwsem);
2876         trace_ext4_writepages(inode, wbc);
2877
2878         ret = dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
2879         trace_ext4_writepages_result(inode, wbc, ret,
2880                                      nr_to_write - wbc->nr_to_write);
2881         percpu_up_read(&sbi->s_writepages_rwsem);
2882         return ret;
2883 }
2884
2885 static int ext4_nonda_switch(struct super_block *sb)
2886 {
2887         s64 free_clusters, dirty_clusters;
2888         struct ext4_sb_info *sbi = EXT4_SB(sb);
2889
2890         /*
2891          * switch to non delalloc mode if we are running low
2892          * on free block. The free block accounting via percpu
2893          * counters can get slightly wrong with percpu_counter_batch getting
2894          * accumulated on each CPU without updating global counters
2895          * Delalloc need an accurate free block accounting. So switch
2896          * to non delalloc when we are near to error range.
2897          */
2898         free_clusters =
2899                 percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2900         dirty_clusters =
2901                 percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2902         /*
2903          * Start pushing delalloc when 1/2 of free blocks are dirty.
2904          */
2905         if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2906                 try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2907
2908         if (2 * free_clusters < 3 * dirty_clusters ||
2909             free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2910                 /*
2911                  * free block count is less than 150% of dirty blocks
2912                  * or free blocks is less than watermark
2913                  */
2914                 return 1;
2915         }
2916         return 0;
2917 }
2918
2919 /* We always reserve for an inode update; the superblock could be there too */
2920 static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
2921 {
2922         if (likely(ext4_has_feature_large_file(inode->i_sb)))
2923                 return 1;
2924
2925         if (pos + len <= 0x7fffffffULL)
2926                 return 1;
2927
2928         /* We might need to update the superblock to set LARGE_FILE */
2929         return 2;
2930 }
2931
2932 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2933                                loff_t pos, unsigned len, unsigned flags,
2934                                struct page **pagep, void **fsdata)
2935 {
2936         int ret, retries = 0;
2937         struct page *page;
2938         pgoff_t index;
2939         struct inode *inode = mapping->host;
2940         handle_t *handle;
2941
2942         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2943                 return -EIO;
2944
2945         index = pos >> PAGE_SHIFT;
2946
2947         if (ext4_nonda_switch(inode->i_sb) || S_ISLNK(inode->i_mode) ||
2948             ext4_verity_in_progress(inode)) {
2949                 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2950                 return ext4_write_begin(file, mapping, pos,
2951                                         len, flags, pagep, fsdata);
2952         }
2953         *fsdata = (void *)0;
2954         trace_ext4_da_write_begin(inode, pos, len, flags);
2955
2956         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2957                 ret = ext4_da_write_inline_data_begin(mapping, inode,
2958                                                       pos, len, flags,
2959                                                       pagep, fsdata);
2960                 if (ret < 0)
2961                         return ret;
2962                 if (ret == 1)
2963                         return 0;
2964         }
2965
2966         /*
2967          * grab_cache_page_write_begin() can take a long time if the
2968          * system is thrashing due to memory pressure, or if the page
2969          * is being written back.  So grab it first before we start
2970          * the transaction handle.  This also allows us to allocate
2971          * the page (if needed) without using GFP_NOFS.
2972          */
2973 retry_grab:
2974         page = grab_cache_page_write_begin(mapping, index, flags);
2975         if (!page)
2976                 return -ENOMEM;
2977         unlock_page(page);
2978
2979         /*
2980          * With delayed allocation, we don't log the i_disksize update
2981          * if there is delayed block allocation. But we still need
2982          * to journalling the i_disksize update if writes to the end
2983          * of file which has an already mapped buffer.
2984          */
2985 retry_journal:
2986         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
2987                                 ext4_da_write_credits(inode, pos, len));
2988         if (IS_ERR(handle)) {
2989                 put_page(page);
2990                 return PTR_ERR(handle);
2991         }
2992
2993         lock_page(page);
2994         if (page->mapping != mapping) {
2995                 /* The page got truncated from under us */
2996                 unlock_page(page);
2997                 put_page(page);
2998                 ext4_journal_stop(handle);
2999                 goto retry_grab;
3000         }
3001         /* In case writeback began while the page was unlocked */
3002         wait_for_stable_page(page);
3003
3004 #ifdef CONFIG_FS_ENCRYPTION
3005         ret = ext4_block_write_begin(page, pos, len,
3006                                      ext4_da_get_block_prep);
3007 #else
3008         ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
3009 #endif
3010         if (ret < 0) {
3011                 unlock_page(page);
3012                 ext4_journal_stop(handle);
3013                 /*
3014                  * block_write_begin may have instantiated a few blocks
3015                  * outside i_size.  Trim these off again. Don't need
3016                  * i_size_read because we hold i_mutex.
3017                  */
3018                 if (pos + len > inode->i_size)
3019                         ext4_truncate_failed_write(inode);
3020
3021                 if (ret == -ENOSPC &&
3022                     ext4_should_retry_alloc(inode->i_sb, &retries))
3023                         goto retry_journal;
3024
3025                 put_page(page);
3026                 return ret;
3027         }
3028
3029         *pagep = page;
3030         return ret;
3031 }
3032
3033 /*
3034  * Check if we should update i_disksize
3035  * when write to the end of file but not require block allocation
3036  */
3037 static int ext4_da_should_update_i_disksize(struct page *page,
3038                                             unsigned long offset)
3039 {
3040         struct buffer_head *bh;
3041         struct inode *inode = page->mapping->host;
3042         unsigned int idx;
3043         int i;
3044
3045         bh = page_buffers(page);
3046         idx = offset >> inode->i_blkbits;
3047
3048         for (i = 0; i < idx; i++)
3049                 bh = bh->b_this_page;
3050
3051         if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3052                 return 0;
3053         return 1;
3054 }
3055
3056 static int ext4_da_write_end(struct file *file,
3057                              struct address_space *mapping,
3058                              loff_t pos, unsigned len, unsigned copied,
3059                              struct page *page, void *fsdata)
3060 {
3061         struct inode *inode = mapping->host;
3062         int ret = 0, ret2;
3063         handle_t *handle = ext4_journal_current_handle();
3064         loff_t new_i_size;
3065         unsigned long start, end;
3066         int write_mode = (int)(unsigned long)fsdata;
3067
3068         if (write_mode == FALL_BACK_TO_NONDELALLOC)
3069                 return ext4_write_end(file, mapping, pos,
3070                                       len, copied, page, fsdata);
3071
3072         trace_ext4_da_write_end(inode, pos, len, copied);
3073         start = pos & (PAGE_SIZE - 1);
3074         end = start + copied - 1;
3075
3076         /*
3077          * generic_write_end() will run mark_inode_dirty() if i_size
3078          * changes.  So let's piggyback the i_disksize mark_inode_dirty
3079          * into that.
3080          */
3081         new_i_size = pos + copied;
3082         if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
3083                 if (ext4_has_inline_data(inode) ||
3084                     ext4_da_should_update_i_disksize(page, end)) {
3085                         ext4_update_i_disksize(inode, new_i_size);
3086                         /* We need to mark inode dirty even if
3087                          * new_i_size is less that inode->i_size
3088                          * bu greater than i_disksize.(hint delalloc)
3089                          */
3090                         ret = ext4_mark_inode_dirty(handle, inode);
3091                 }
3092         }
3093
3094         if (write_mode != CONVERT_INLINE_DATA &&
3095             ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3096             ext4_has_inline_data(inode))
3097                 ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
3098                                                      page);
3099         else
3100                 ret2 = generic_write_end(file, mapping, pos, len, copied,
3101                                                         page, fsdata);
3102
3103         copied = ret2;
3104         if (ret2 < 0)
3105                 ret = ret2;
3106         ret2 = ext4_journal_stop(handle);
3107         if (unlikely(ret2 && !ret))
3108                 ret = ret2;
3109
3110         return ret ? ret : copied;
3111 }
3112
3113 /*
3114  * Force all delayed allocation blocks to be allocated for a given inode.
3115  */
3116 int ext4_alloc_da_blocks(struct inode *inode)
3117 {
3118         trace_ext4_alloc_da_blocks(inode);
3119
3120         if (!EXT4_I(inode)->i_reserved_data_blocks)
3121                 return 0;
3122
3123         /*
3124          * We do something simple for now.  The filemap_flush() will
3125          * also start triggering a write of the data blocks, which is
3126          * not strictly speaking necessary (and for users of
3127          * laptop_mode, not even desirable).  However, to do otherwise
3128          * would require replicating code paths in:
3129          *
3130          * ext4_writepages() ->
3131          *    write_cache_pages() ---> (via passed in callback function)
3132          *        __mpage_da_writepage() -->
3133          *           mpage_add_bh_to_extent()
3134          *           mpage_da_map_blocks()
3135          *
3136          * The problem is that write_cache_pages(), located in
3137          * mm/page-writeback.c, marks pages clean in preparation for
3138          * doing I/O, which is not desirable if we're not planning on
3139          * doing I/O at all.
3140          *
3141          * We could call write_cache_pages(), and then redirty all of
3142          * the pages by calling redirty_page_for_writepage() but that
3143          * would be ugly in the extreme.  So instead we would need to
3144          * replicate parts of the code in the above functions,
3145          * simplifying them because we wouldn't actually intend to
3146          * write out the pages, but rather only collect contiguous
3147          * logical block extents, call the multi-block allocator, and
3148          * then update the buffer heads with the block allocations.
3149          *
3150          * For now, though, we'll cheat by calling filemap_flush(),
3151          * which will map the blocks, and start the I/O, but not
3152          * actually wait for the I/O to complete.
3153          */
3154         return filemap_flush(inode->i_mapping);
3155 }
3156
3157 /*
3158  * bmap() is special.  It gets used by applications such as lilo and by
3159  * the swapper to find the on-disk block of a specific piece of data.
3160  *
3161  * Naturally, this is dangerous if the block concerned is still in the
3162  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3163  * filesystem and enables swap, then they may get a nasty shock when the
3164  * data getting swapped to that swapfile suddenly gets overwritten by
3165  * the original zero's written out previously to the journal and
3166  * awaiting writeback in the kernel's buffer cache.
3167  *
3168  * So, if we see any bmap calls here on a modified, data-journaled file,
3169  * take extra steps to flush any blocks which might be in the cache.
3170  */
3171 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3172 {
3173         struct inode *inode = mapping->host;
3174         journal_t *journal;
3175         int err;
3176
3177         /*
3178          * We can get here for an inline file via the FIBMAP ioctl
3179          */
3180         if (ext4_has_inline_data(inode))
3181                 return 0;
3182
3183         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3184                         test_opt(inode->i_sb, DELALLOC)) {
3185                 /*
3186                  * With delalloc we want to sync the file
3187                  * so that we can make sure we allocate
3188                  * blocks for file
3189                  */
3190                 filemap_write_and_wait(mapping);
3191         }
3192
3193         if (EXT4_JOURNAL(inode) &&
3194             ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3195                 /*
3196                  * This is a REALLY heavyweight approach, but the use of
3197                  * bmap on dirty files is expected to be extremely rare:
3198                  * only if we run lilo or swapon on a freshly made file
3199                  * do we expect this to happen.
3200                  *
3201                  * (bmap requires CAP_SYS_RAWIO so this does not
3202                  * represent an unprivileged user DOS attack --- we'd be
3203                  * in trouble if mortal users could trigger this path at
3204                  * will.)
3205                  *
3206                  * NB. EXT4_STATE_JDATA is not set on files other than
3207                  * regular files.  If somebody wants to bmap a directory
3208                  * or symlink and gets confused because the buffer
3209                  * hasn't yet been flushed to disk, they deserve
3210                  * everything they get.
3211                  */
3212
3213                 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3214                 journal = EXT4_JOURNAL(inode);
3215                 jbd2_journal_lock_updates(journal);
3216                 err = jbd2_journal_flush(journal);
3217                 jbd2_journal_unlock_updates(journal);
3218
3219                 if (err)
3220                         return 0;
3221         }
3222
3223         return iomap_bmap(mapping, block, &ext4_iomap_ops);
3224 }
3225
3226 static int ext4_readpage(struct file *file, struct page *page)
3227 {
3228         int ret = -EAGAIN;
3229         struct inode *inode = page->mapping->host;
3230
3231         trace_ext4_readpage(page);
3232
3233         if (ext4_has_inline_data(inode))
3234                 ret = ext4_readpage_inline(inode, page);
3235
3236         if (ret == -EAGAIN)
3237                 return ext4_mpage_readpages(inode, NULL, page);
3238
3239         return ret;
3240 }
3241
3242 static void ext4_readahead(struct readahead_control *rac)
3243 {
3244         struct inode *inode = rac->mapping->host;
3245
3246         /* If the file has inline data, no need to do readahead. */
3247         if (ext4_has_inline_data(inode))
3248                 return;
3249
3250         ext4_mpage_readpages(inode, rac, NULL);
3251 }
3252
3253 static void ext4_invalidatepage(struct page *page, unsigned int offset,
3254                                 unsigned int length)
3255 {
3256         trace_ext4_invalidatepage(page, offset, length);
3257
3258         /* No journalling happens on data buffers when this function is used */
3259         WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
3260
3261         block_invalidatepage(page, offset, length);
3262 }
3263
3264 static int __ext4_journalled_invalidatepage(struct page *page,
3265                                             unsigned int offset,
3266                                             unsigned int length)
3267 {
3268         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3269
3270         trace_ext4_journalled_invalidatepage(page, offset, length);
3271
3272         /*
3273          * If it's a full truncate we just forget about the pending dirtying
3274          */
3275         if (offset == 0 && length == PAGE_SIZE)
3276                 ClearPageChecked(page);
3277
3278         return jbd2_journal_invalidatepage(journal, page, offset, length);
3279 }
3280
3281 /* Wrapper for aops... */
3282 static void ext4_journalled_invalidatepage(struct page *page,
3283                                            unsigned int offset,
3284                                            unsigned int length)
3285 {
3286         WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3287 }
3288
3289 static int ext4_releasepage(struct page *page, gfp_t wait)
3290 {
3291         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3292
3293         trace_ext4_releasepage(page);
3294
3295         /* Page has dirty journalled data -> cannot release */
3296         if (PageChecked(page))
3297                 return 0;
3298         if (journal)
3299                 return jbd2_journal_try_to_free_buffers(journal, page);
3300         else
3301                 return try_to_free_buffers(page);
3302 }
3303
3304 static bool ext4_inode_datasync_dirty(struct inode *inode)
3305 {
3306         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3307
3308         if (journal) {
3309                 if (jbd2_transaction_committed(journal,
3310                         EXT4_I(inode)->i_datasync_tid))
3311                         return false;
3312                 if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
3313                         return atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid) <
3314                                 EXT4_I(inode)->i_fc_committed_subtid;
3315                 return true;
3316         }
3317
3318         /* Any metadata buffers to write? */
3319         if (!list_empty(&inode->i_mapping->private_list))
3320                 return true;
3321         return inode->i_state & I_DIRTY_DATASYNC;
3322 }
3323
3324 static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
3325                            struct ext4_map_blocks *map, loff_t offset,
3326                            loff_t length)
3327 {
3328         u8 blkbits = inode->i_blkbits;
3329
3330         /*
3331          * Writes that span EOF might trigger an I/O size update on completion,
3332          * so consider them to be dirty for the purpose of O_DSYNC, even if
3333          * there is no other metadata changes being made or are pending.
3334          */
3335         iomap->flags = 0;
3336         if (ext4_inode_datasync_dirty(inode) ||
3337             offset + length > i_size_read(inode))
3338                 iomap->flags |= IOMAP_F_DIRTY;
3339
3340         if (map->m_flags & EXT4_MAP_NEW)
3341                 iomap->flags |= IOMAP_F_NEW;
3342
3343         iomap->bdev = inode->i_sb->s_bdev;
3344         iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
3345         iomap->offset = (u64) map->m_lblk << blkbits;
3346         iomap->length = (u64) map->m_len << blkbits;
3347
3348         if ((map->m_flags & EXT4_MAP_MAPPED) &&
3349             !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3350                 iomap->flags |= IOMAP_F_MERGED;
3351
3352         /*
3353          * Flags passed to ext4_map_blocks() for direct I/O writes can result
3354          * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3355          * set. In order for any allocated unwritten extents to be converted
3356          * into written extents correctly within the ->end_io() handler, we
3357          * need to ensure that the iomap->type is set appropriately. Hence, the
3358          * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3359          * been set first.
3360          */
3361         if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3362                 iomap->type = IOMAP_UNWRITTEN;
3363                 iomap->addr = (u64) map->m_pblk << blkbits;
3364         } else if (map->m_flags & EXT4_MAP_MAPPED) {
3365                 iomap->type = IOMAP_MAPPED;
3366                 iomap->addr = (u64) map->m_pblk << blkbits;
3367         } else {
3368                 iomap->type = IOMAP_HOLE;
3369                 iomap->addr = IOMAP_NULL_ADDR;
3370         }
3371 }
3372
3373 static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
3374                             unsigned int flags)
3375 {
3376         handle_t *handle;
3377         u8 blkbits = inode->i_blkbits;
3378         int ret, dio_credits, m_flags = 0, retries = 0;
3379
3380         /*
3381          * Trim the mapping request to the maximum value that we can map at
3382          * once for direct I/O.
3383          */
3384         if (map->m_len > DIO_MAX_BLOCKS)
3385                 map->m_len = DIO_MAX_BLOCKS;
3386         dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
3387
3388 retry:
3389         /*
3390          * Either we allocate blocks and then don't get an unwritten extent, so
3391          * in that case we have reserved enough credits. Or, the blocks are
3392          * already allocated and unwritten. In that case, the extent conversion
3393          * fits into the credits as well.
3394          */
3395         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3396         if (IS_ERR(handle))
3397                 return PTR_ERR(handle);
3398
3399         /*
3400          * DAX and direct I/O are the only two operations that are currently
3401          * supported with IOMAP_WRITE.
3402          */
3403         WARN_ON(!IS_DAX(inode) && !(flags & IOMAP_DIRECT));
3404         if (IS_DAX(inode))
3405                 m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3406         /*
3407          * We use i_size instead of i_disksize here because delalloc writeback
3408          * can complete at any point during the I/O and subsequently push the
3409          * i_disksize out to i_size. This could be beyond where direct I/O is
3410          * happening and thus expose allocated blocks to direct I/O reads.
3411          */
3412         else if ((map->m_lblk * (1 << blkbits)) >= i_size_read(inode))
3413                 m_flags = EXT4_GET_BLOCKS_CREATE;
3414         else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3415                 m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3416
3417         ret = ext4_map_blocks(handle, inode, map, m_flags);
3418
3419         /*
3420          * We cannot fill holes in indirect tree based inodes as that could
3421          * expose stale data in the case of a crash. Use the magic error code
3422          * to fallback to buffered I/O.
3423          */
3424         if (!m_flags && !ret)
3425                 ret = -ENOTBLK;
3426
3427         ext4_journal_stop(handle);
3428         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3429                 goto retry;
3430
3431         return ret;
3432 }
3433
3434
3435 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3436                 unsigned flags, struct iomap *iomap, struct iomap *srcmap)
3437 {
3438         int ret;
3439         struct ext4_map_blocks map;
3440         u8 blkbits = inode->i_blkbits;
3441
3442         if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3443                 return -EINVAL;
3444
3445         if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3446                 return -ERANGE;
3447
3448         /*
3449          * Calculate the first and last logical blocks respectively.
3450          */
3451         map.m_lblk = offset >> blkbits;
3452         map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3453                           EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3454
3455         if (flags & IOMAP_WRITE) {
3456                 /*
3457                  * We check here if the blocks are already allocated, then we
3458                  * don't need to start a journal txn and we can directly return
3459                  * the mapping information. This could boost performance
3460                  * especially in multi-threaded overwrite requests.
3461                  */
3462                 if (offset + length <= i_size_read(inode)) {
3463                         ret = ext4_map_blocks(NULL, inode, &map, 0);
3464                         if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
3465                                 goto out;
3466                 }
3467                 ret = ext4_iomap_alloc(inode, &map, flags);
3468         } else {
3469                 ret = ext4_map_blocks(NULL, inode, &map, 0);
3470         }
3471
3472         if (ret < 0)
3473                 return ret;
3474 out:
3475         ext4_set_iomap(inode, iomap, &map, offset, length);
3476
3477         return 0;
3478 }
3479
3480 static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3481                 loff_t length, unsigned flags, struct iomap *iomap,
3482                 struct iomap *srcmap)
3483 {
3484         int ret;
3485
3486         /*
3487          * Even for writes we don't need to allocate blocks, so just pretend
3488          * we are reading to save overhead of starting a transaction.
3489          */
3490         flags &= ~IOMAP_WRITE;
3491         ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3492         WARN_ON_ONCE(iomap->type != IOMAP_MAPPED);
3493         return ret;
3494 }
3495
3496 static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3497                           ssize_t written, unsigned flags, struct iomap *iomap)
3498 {
3499         /*
3500          * Check to see whether an error occurred while writing out the data to
3501          * the allocated blocks. If so, return the magic error code so that we
3502          * fallback to buffered I/O and attempt to complete the remainder of
3503          * the I/O. Any blocks that may have been allocated in preparation for
3504          * the direct I/O will be reused during buffered I/O.
3505          */
3506         if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
3507                 return -ENOTBLK;
3508
3509         return 0;
3510 }
3511
3512 const struct iomap_ops ext4_iomap_ops = {
3513         .iomap_begin            = ext4_iomap_begin,
3514         .iomap_end              = ext4_iomap_end,
3515 };
3516
3517 const struct iomap_ops ext4_iomap_overwrite_ops = {
3518         .iomap_begin            = ext4_iomap_overwrite_begin,
3519         .iomap_end              = ext4_iomap_end,
3520 };
3521
3522 static bool ext4_iomap_is_delalloc(struct inode *inode,
3523                                    struct ext4_map_blocks *map)
3524 {
3525         struct extent_status es;
3526         ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1;
3527
3528         ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
3529                                   map->m_lblk, end, &es);
3530
3531         if (!es.es_len || es.es_lblk > end)
3532                 return false;
3533
3534         if (es.es_lblk > map->m_lblk) {
3535                 map->m_len = es.es_lblk - map->m_lblk;
3536                 return false;
3537         }
3538
3539         offset = map->m_lblk - es.es_lblk;
3540         map->m_len = es.es_len - offset;
3541
3542         return true;
3543 }
3544
3545 static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3546                                    loff_t length, unsigned int flags,
3547                                    struct iomap *iomap, struct iomap *srcmap)
3548 {
3549         int ret;
3550         bool delalloc = false;
3551         struct ext4_map_blocks map;
3552         u8 blkbits = inode->i_blkbits;
3553
3554         if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3555                 return -EINVAL;
3556
3557         if (ext4_has_inline_data(inode)) {
3558                 ret = ext4_inline_data_iomap(inode, iomap);
3559                 if (ret != -EAGAIN) {
3560                         if (ret == 0 && offset >= iomap->length)
3561                                 ret = -ENOENT;
3562                         return ret;
3563                 }
3564         }
3565
3566         /*
3567          * Calculate the first and last logical block respectively.
3568          */
3569         map.m_lblk = offset >> blkbits;
3570         map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3571                           EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3572
3573         /*
3574          * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3575          * So handle it here itself instead of querying ext4_map_blocks().
3576          * Since ext4_map_blocks() will warn about it and will return
3577          * -EIO error.
3578          */
3579         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3580                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3581
3582                 if (offset >= sbi->s_bitmap_maxbytes) {
3583                         map.m_flags = 0;
3584                         goto set_iomap;
3585                 }
3586         }
3587
3588         ret = ext4_map_blocks(NULL, inode, &map, 0);
3589         if (ret < 0)
3590                 return ret;
3591         if (ret == 0)
3592                 delalloc = ext4_iomap_is_delalloc(inode, &map);
3593
3594 set_iomap:
3595         ext4_set_iomap(inode, iomap, &map, offset, length);
3596         if (delalloc && iomap->type == IOMAP_HOLE)
3597                 iomap->type = IOMAP_DELALLOC;
3598
3599         return 0;
3600 }
3601
3602 const struct iomap_ops ext4_iomap_report_ops = {
3603         .iomap_begin = ext4_iomap_begin_report,
3604 };
3605
3606 /*
3607  * Pages can be marked dirty completely asynchronously from ext4's journalling
3608  * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3609  * much here because ->set_page_dirty is called under VFS locks.  The page is
3610  * not necessarily locked.
3611  *
3612  * We cannot just dirty the page and leave attached buffers clean, because the
3613  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3614  * or jbddirty because all the journalling code will explode.
3615  *
3616  * So what we do is to mark the page "pending dirty" and next time writepage
3617  * is called, propagate that into the buffers appropriately.
3618  */
3619 static int ext4_journalled_set_page_dirty(struct page *page)
3620 {
3621         SetPageChecked(page);
3622         return __set_page_dirty_nobuffers(page);
3623 }
3624
3625 static int ext4_set_page_dirty(struct page *page)
3626 {
3627         WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page));
3628         WARN_ON_ONCE(!page_has_buffers(page));
3629         return __set_page_dirty_buffers(page);
3630 }
3631
3632 static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
3633                                     struct file *file, sector_t *span)
3634 {
3635         return iomap_swapfile_activate(sis, file, span,
3636                                        &ext4_iomap_report_ops);
3637 }
3638
3639 static const struct address_space_operations ext4_aops = {
3640         .readpage               = ext4_readpage,
3641         .readahead              = ext4_readahead,
3642         .writepage              = ext4_writepage,
3643         .writepages             = ext4_writepages,
3644         .write_begin            = ext4_write_begin,
3645         .write_end              = ext4_write_end,
3646         .set_page_dirty         = ext4_set_page_dirty,
3647         .bmap                   = ext4_bmap,
3648         .invalidatepage         = ext4_invalidatepage,
3649         .releasepage            = ext4_releasepage,
3650         .direct_IO              = noop_direct_IO,
3651         .migratepage            = buffer_migrate_page,
3652         .is_partially_uptodate  = block_is_partially_uptodate,
3653         .error_remove_page      = generic_error_remove_page,
3654         .swap_activate          = ext4_iomap_swap_activate,
3655 };
3656
3657 static const struct address_space_operations ext4_journalled_aops = {
3658         .readpage               = ext4_readpage,
3659         .readahead              = ext4_readahead,
3660         .writepage              = ext4_writepage,
3661         .writepages             = ext4_writepages,
3662         .write_begin            = ext4_write_begin,
3663         .write_end              = ext4_journalled_write_end,
3664         .set_page_dirty         = ext4_journalled_set_page_dirty,
3665         .bmap                   = ext4_bmap,
3666         .invalidatepage         = ext4_journalled_invalidatepage,
3667         .releasepage            = ext4_releasepage,
3668         .direct_IO              = noop_direct_IO,
3669         .is_partially_uptodate  = block_is_partially_uptodate,
3670         .error_remove_page      = generic_error_remove_page,
3671         .swap_activate          = ext4_iomap_swap_activate,
3672 };
3673
3674 static const struct address_space_operations ext4_da_aops = {
3675         .readpage               = ext4_readpage,
3676         .readahead              = ext4_readahead,
3677         .writepage              = ext4_writepage,
3678         .writepages             = ext4_writepages,
3679         .write_begin            = ext4_da_write_begin,
3680         .write_end              = ext4_da_write_end,
3681         .set_page_dirty         = ext4_set_page_dirty,
3682         .bmap                   = ext4_bmap,
3683         .invalidatepage         = ext4_invalidatepage,
3684         .releasepage            = ext4_releasepage,
3685         .direct_IO              = noop_direct_IO,
3686         .migratepage            = buffer_migrate_page,
3687         .is_partially_uptodate  = block_is_partially_uptodate,
3688         .error_remove_page      = generic_error_remove_page,
3689         .swap_activate          = ext4_iomap_swap_activate,
3690 };
3691
3692 static const struct address_space_operations ext4_dax_aops = {
3693         .writepages             = ext4_dax_writepages,
3694         .direct_IO              = noop_direct_IO,
3695         .set_page_dirty         = noop_set_page_dirty,
3696         .bmap                   = ext4_bmap,
3697         .invalidatepage         = noop_invalidatepage,
3698         .swap_activate          = ext4_iomap_swap_activate,
3699 };
3700
3701 void ext4_set_aops(struct inode *inode)
3702 {
3703         switch (ext4_inode_journal_mode(inode)) {
3704         case EXT4_INODE_ORDERED_DATA_MODE:
3705         case EXT4_INODE_WRITEBACK_DATA_MODE:
3706                 break;
3707         case EXT4_INODE_JOURNAL_DATA_MODE:
3708                 inode->i_mapping->a_ops = &ext4_journalled_aops;
3709                 return;
3710         default:
3711                 BUG();
3712         }
3713         if (IS_DAX(inode))
3714                 inode->i_mapping->a_ops = &ext4_dax_aops;
3715         else if (test_opt(inode->i_sb, DELALLOC))
3716                 inode->i_mapping->a_ops = &ext4_da_aops;
3717         else
3718                 inode->i_mapping->a_ops = &ext4_aops;
3719 }
3720
3721 static int __ext4_block_zero_page_range(handle_t *handle,
3722                 struct address_space *mapping, loff_t from, loff_t length)
3723 {
3724         ext4_fsblk_t index = from >> PAGE_SHIFT;
3725         unsigned offset = from & (PAGE_SIZE-1);
3726         unsigned blocksize, pos;
3727         ext4_lblk_t iblock;
3728         struct inode *inode = mapping->host;
3729         struct buffer_head *bh;
3730         struct page *page;
3731         int err = 0;
3732
3733         page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3734                                    mapping_gfp_constraint(mapping, ~__GFP_FS));
3735         if (!page)
3736                 return -ENOMEM;
3737
3738         blocksize = inode->i_sb->s_blocksize;
3739
3740         iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3741
3742         if (!page_has_buffers(page))
3743                 create_empty_buffers(page, blocksize, 0);
3744
3745         /* Find the buffer that contains "offset" */
3746         bh = page_buffers(page);
3747         pos = blocksize;
3748         while (offset >= pos) {
3749                 bh = bh->b_this_page;
3750                 iblock++;
3751                 pos += blocksize;
3752         }
3753         if (buffer_freed(bh)) {
3754                 BUFFER_TRACE(bh, "freed: skip");
3755                 goto unlock;
3756         }
3757         if (!buffer_mapped(bh)) {
3758                 BUFFER_TRACE(bh, "unmapped");
3759                 ext4_get_block(inode, iblock, bh, 0);
3760                 /* unmapped? It's a hole - nothing to do */
3761                 if (!buffer_mapped(bh)) {
3762                         BUFFER_TRACE(bh, "still unmapped");
3763                         goto unlock;
3764                 }
3765         }
3766
3767         /* Ok, it's mapped. Make sure it's up-to-date */
3768         if (PageUptodate(page))
3769                 set_buffer_uptodate(bh);
3770
3771         if (!buffer_uptodate(bh)) {
3772                 err = ext4_read_bh_lock(bh, 0, true);
3773                 if (err)
3774                         goto unlock;
3775                 if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
3776                         /* We expect the key to be set. */
3777                         BUG_ON(!fscrypt_has_encryption_key(inode));
3778                         err = fscrypt_decrypt_pagecache_blocks(page, blocksize,
3779                                                                bh_offset(bh));
3780                         if (err) {
3781                                 clear_buffer_uptodate(bh);
3782                                 goto unlock;
3783                         }
3784                 }
3785         }
3786         if (ext4_should_journal_data(inode)) {
3787                 BUFFER_TRACE(bh, "get write access");
3788                 err = ext4_journal_get_write_access(handle, bh);
3789                 if (err)
3790                         goto unlock;
3791         }
3792         zero_user(page, offset, length);
3793         BUFFER_TRACE(bh, "zeroed end of block");
3794
3795         if (ext4_should_journal_data(inode)) {
3796                 err = ext4_handle_dirty_metadata(handle, inode, bh);
3797         } else {
3798                 err = 0;
3799                 mark_buffer_dirty(bh);
3800                 if (ext4_should_order_data(inode))
3801                         err = ext4_jbd2_inode_add_write(handle, inode, from,
3802                                         length);
3803         }
3804
3805 unlock:
3806         unlock_page(page);
3807         put_page(page);
3808         return err;
3809 }
3810
3811 /*
3812  * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3813  * starting from file offset 'from'.  The range to be zero'd must
3814  * be contained with in one block.  If the specified range exceeds
3815  * the end of the block it will be shortened to end of the block
3816  * that cooresponds to 'from'
3817  */
3818 static int ext4_block_zero_page_range(handle_t *handle,
3819                 struct address_space *mapping, loff_t from, loff_t length)
3820 {
3821         struct inode *inode = mapping->host;
3822         unsigned offset = from & (PAGE_SIZE-1);
3823         unsigned blocksize = inode->i_sb->s_blocksize;
3824         unsigned max = blocksize - (offset & (blocksize - 1));
3825
3826         /*
3827          * correct length if it does not fall between
3828          * 'from' and the end of the block
3829          */
3830         if (length > max || length < 0)
3831                 length = max;
3832
3833         if (IS_DAX(inode)) {
3834                 return iomap_zero_range(inode, from, length, NULL,
3835                                         &ext4_iomap_ops);
3836         }
3837         return __ext4_block_zero_page_range(handle, mapping, from, length);
3838 }
3839
3840 /*
3841  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3842  * up to the end of the block which corresponds to `from'.
3843  * This required during truncate. We need to physically zero the tail end
3844  * of that block so it doesn't yield old data if the file is later grown.
3845  */
3846 static int ext4_block_truncate_page(handle_t *handle,
3847                 struct address_space *mapping, loff_t from)
3848 {
3849         unsigned offset = from & (PAGE_SIZE-1);
3850         unsigned length;
3851         unsigned blocksize;
3852         struct inode *inode = mapping->host;
3853
3854         /* If we are processing an encrypted inode during orphan list handling */
3855         if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
3856                 return 0;
3857
3858         blocksize = inode->i_sb->s_blocksize;
3859         length = blocksize - (offset & (blocksize - 1));
3860
3861         return ext4_block_zero_page_range(handle, mapping, from, length);
3862 }
3863
3864 int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3865                              loff_t lstart, loff_t length)
3866 {
3867         struct super_block *sb = inode->i_sb;
3868         struct address_space *mapping = inode->i_mapping;
3869         unsigned partial_start, partial_end;
3870         ext4_fsblk_t start, end;
3871         loff_t byte_end = (lstart + length - 1);
3872         int err = 0;
3873
3874         partial_start = lstart & (sb->s_blocksize - 1);
3875         partial_end = byte_end & (sb->s_blocksize - 1);
3876
3877         start = lstart >> sb->s_blocksize_bits;
3878         end = byte_end >> sb->s_blocksize_bits;
3879
3880         /* Handle partial zero within the single block */
3881         if (start == end &&
3882             (partial_start || (partial_end != sb->s_blocksize - 1))) {
3883                 err = ext4_block_zero_page_range(handle, mapping,
3884                                                  lstart, length);
3885                 return err;
3886         }
3887         /* Handle partial zero out on the start of the range */
3888         if (partial_start) {
3889                 err = ext4_block_zero_page_range(handle, mapping,
3890                                                  lstart, sb->s_blocksize);
3891                 if (err)
3892                         return err;
3893         }
3894         /* Handle partial zero out on the end of the range */
3895         if (partial_end != sb->s_blocksize - 1)
3896                 err = ext4_block_zero_page_range(handle, mapping,
3897                                                  byte_end - partial_end,
3898                                                  partial_end + 1);
3899         return err;
3900 }
3901
3902 int ext4_can_truncate(struct inode *inode)
3903 {
3904         if (S_ISREG(inode->i_mode))
3905                 return 1;
3906         if (S_ISDIR(inode->i_mode))
3907                 return 1;
3908         if (S_ISLNK(inode->i_mode))
3909                 return !ext4_inode_is_fast_symlink(inode);
3910         return 0;
3911 }
3912
3913 /*
3914  * We have to make sure i_disksize gets properly updated before we truncate
3915  * page cache due to hole punching or zero range. Otherwise i_disksize update
3916  * can get lost as it may have been postponed to submission of writeback but
3917  * that will never happen after we truncate page cache.
3918  */
3919 int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3920                                       loff_t len)
3921 {
3922         handle_t *handle;
3923         int ret;
3924
3925         loff_t size = i_size_read(inode);
3926
3927         WARN_ON(!inode_is_locked(inode));
3928         if (offset > size || offset + len < size)
3929                 return 0;
3930
3931         if (EXT4_I(inode)->i_disksize >= size)
3932                 return 0;
3933
3934         handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3935         if (IS_ERR(handle))
3936                 return PTR_ERR(handle);
3937         ext4_update_i_disksize(inode, size);
3938         ret = ext4_mark_inode_dirty(handle, inode);
3939         ext4_journal_stop(handle);
3940
3941         return ret;
3942 }
3943
3944 static void ext4_wait_dax_page(struct ext4_inode_info *ei)
3945 {
3946         up_write(&ei->i_mmap_sem);
3947         schedule();
3948         down_write(&ei->i_mmap_sem);
3949 }
3950
3951 int ext4_break_layouts(struct inode *inode)
3952 {
3953         struct ext4_inode_info *ei = EXT4_I(inode);
3954         struct page *page;
3955         int error;
3956
3957         if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem)))
3958                 return -EINVAL;
3959
3960         do {
3961                 page = dax_layout_busy_page(inode->i_mapping);
3962                 if (!page)
3963                         return 0;
3964
3965                 error = ___wait_var_event(&page->_refcount,
3966                                 atomic_read(&page->_refcount) == 1,
3967                                 TASK_INTERRUPTIBLE, 0, 0,
3968                                 ext4_wait_dax_page(ei));
3969         } while (error == 0);
3970
3971         return error;
3972 }
3973
3974 /*
3975  * ext4_punch_hole: punches a hole in a file by releasing the blocks
3976  * associated with the given offset and length
3977  *
3978  * @inode:  File inode
3979  * @offset: The offset where the hole will begin
3980  * @len:    The length of the hole
3981  *
3982  * Returns: 0 on success or negative on failure
3983  */
3984
3985 int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
3986 {
3987         struct super_block *sb = inode->i_sb;
3988         ext4_lblk_t first_block, stop_block;
3989         struct address_space *mapping = inode->i_mapping;
3990         loff_t first_block_offset, last_block_offset;
3991         handle_t *handle;
3992         unsigned int credits;
3993         int ret = 0, ret2 = 0;
3994
3995         trace_ext4_punch_hole(inode, offset, length, 0);
3996
3997         ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
3998         if (ext4_has_inline_data(inode)) {
3999                 down_write(&EXT4_I(inode)->i_mmap_sem);
4000                 ret = ext4_convert_inline_data(inode);
4001                 up_write(&EXT4_I(inode)->i_mmap_sem);
4002                 if (ret)
4003                         return ret;
4004         }
4005
4006         /*
4007          * Write out all dirty pages to avoid race conditions
4008          * Then release them.
4009          */
4010         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4011                 ret = filemap_write_and_wait_range(mapping, offset,
4012                                                    offset + length - 1);
4013                 if (ret)
4014                         return ret;
4015         }
4016
4017         inode_lock(inode);
4018
4019         /* No need to punch hole beyond i_size */
4020         if (offset >= inode->i_size)
4021                 goto out_mutex;
4022
4023         /*
4024          * If the hole extends beyond i_size, set the hole
4025          * to end after the page that contains i_size
4026          */
4027         if (offset + length > inode->i_size) {
4028                 length = inode->i_size +
4029                    PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
4030                    offset;
4031         }
4032
4033         if (offset & (sb->s_blocksize - 1) ||
4034             (offset + length) & (sb->s_blocksize - 1)) {
4035                 /*
4036                  * Attach jinode to inode for jbd2 if we do any zeroing of
4037                  * partial block
4038                  */
4039                 ret = ext4_inode_attach_jinode(inode);
4040                 if (ret < 0)
4041                         goto out_mutex;
4042
4043         }
4044
4045         /* Wait all existing dio workers, newcomers will block on i_mutex */
4046         inode_dio_wait(inode);
4047
4048         /*
4049          * Prevent page faults from reinstantiating pages we have released from
4050          * page cache.
4051          */
4052         down_write(&EXT4_I(inode)->i_mmap_sem);
4053
4054         ret = ext4_break_layouts(inode);
4055         if (ret)
4056                 goto out_dio;
4057
4058         first_block_offset = round_up(offset, sb->s_blocksize);
4059         last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
4060
4061         /* Now release the pages and zero block aligned part of pages*/
4062         if (last_block_offset > first_block_offset) {
4063                 ret = ext4_update_disksize_before_punch(inode, offset, length);
4064                 if (ret)
4065                         goto out_dio;
4066                 truncate_pagecache_range(inode, first_block_offset,
4067                                          last_block_offset);
4068         }
4069
4070         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4071                 credits = ext4_writepage_trans_blocks(inode);
4072         else
4073                 credits = ext4_blocks_for_truncate(inode);
4074         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4075         if (IS_ERR(handle)) {
4076                 ret = PTR_ERR(handle);
4077                 ext4_std_error(sb, ret);
4078                 goto out_dio;
4079         }
4080
4081         ret = ext4_zero_partial_blocks(handle, inode, offset,
4082                                        length);
4083         if (ret)
4084                 goto out_stop;
4085
4086         first_block = (offset + sb->s_blocksize - 1) >>
4087                 EXT4_BLOCK_SIZE_BITS(sb);
4088         stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4089
4090         /* If there are blocks to remove, do it */
4091         if (stop_block > first_block) {
4092
4093                 down_write(&EXT4_I(inode)->i_data_sem);
4094                 ext4_discard_preallocations(inode, 0);
4095
4096                 ret = ext4_es_remove_extent(inode, first_block,
4097                                             stop_block - first_block);
4098                 if (ret) {
4099                         up_write(&EXT4_I(inode)->i_data_sem);
4100                         goto out_stop;
4101                 }
4102
4103                 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4104                         ret = ext4_ext_remove_space(inode, first_block,
4105                                                     stop_block - 1);
4106                 else
4107                         ret = ext4_ind_remove_space(handle, inode, first_block,
4108                                                     stop_block);
4109
4110                 up_write(&EXT4_I(inode)->i_data_sem);
4111         }
4112         ext4_fc_track_range(inode, first_block, stop_block);
4113         if (IS_SYNC(inode))
4114                 ext4_handle_sync(handle);
4115
4116         inode->i_mtime = inode->i_ctime = current_time(inode);
4117         ret2 = ext4_mark_inode_dirty(handle, inode);
4118         if (unlikely(ret2))
4119                 ret = ret2;
4120         if (ret >= 0)
4121                 ext4_update_inode_fsync_trans(handle, inode, 1);
4122 out_stop:
4123         ext4_journal_stop(handle);
4124 out_dio:
4125         up_write(&EXT4_I(inode)->i_mmap_sem);
4126 out_mutex:
4127         inode_unlock(inode);
4128         return ret;
4129 }
4130
4131 int ext4_inode_attach_jinode(struct inode *inode)
4132 {
4133         struct ext4_inode_info *ei = EXT4_I(inode);
4134         struct jbd2_inode *jinode;
4135
4136         if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4137                 return 0;
4138
4139         jinode = jbd2_alloc_inode(GFP_KERNEL);
4140         spin_lock(&inode->i_lock);
4141         if (!ei->jinode) {
4142                 if (!jinode) {
4143                         spin_unlock(&inode->i_lock);
4144                         return -ENOMEM;
4145                 }
4146                 ei->jinode = jinode;
4147                 jbd2_journal_init_jbd_inode(ei->jinode, inode);
4148                 jinode = NULL;
4149         }
4150         spin_unlock(&inode->i_lock);
4151         if (unlikely(jinode != NULL))
4152                 jbd2_free_inode(jinode);
4153         return 0;
4154 }
4155
4156 /*
4157  * ext4_truncate()
4158  *
4159  * We block out ext4_get_block() block instantiations across the entire
4160  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4161  * simultaneously on behalf of the same inode.
4162  *
4163  * As we work through the truncate and commit bits of it to the journal there
4164  * is one core, guiding principle: the file's tree must always be consistent on
4165  * disk.  We must be able to restart the truncate after a crash.
4166  *
4167  * The file's tree may be transiently inconsistent in memory (although it
4168  * probably isn't), but whenever we close off and commit a journal transaction,
4169  * the contents of (the filesystem + the journal) must be consistent and
4170  * restartable.  It's pretty simple, really: bottom up, right to left (although
4171  * left-to-right works OK too).
4172  *
4173  * Note that at recovery time, journal replay occurs *before* the restart of
4174  * truncate against the orphan inode list.
4175  *
4176  * The committed inode has the new, desired i_size (which is the same as
4177  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4178  * that this inode's truncate did not complete and it will again call
4179  * ext4_truncate() to have another go.  So there will be instantiated blocks
4180  * to the right of the truncation point in a crashed ext4 filesystem.  But
4181  * that's fine - as long as they are linked from the inode, the post-crash
4182  * ext4_truncate() run will find them and release them.
4183  */
4184 int ext4_truncate(struct inode *inode)
4185 {
4186         struct ext4_inode_info *ei = EXT4_I(inode);
4187         unsigned int credits;
4188         int err = 0, err2;
4189         handle_t *handle;
4190         struct address_space *mapping = inode->i_mapping;
4191
4192         /*
4193          * There is a possibility that we're either freeing the inode
4194          * or it's a completely new inode. In those cases we might not
4195          * have i_mutex locked because it's not necessary.
4196          */
4197         if (!(inode->i_state & (I_NEW|I_FREEING)))
4198                 WARN_ON(!inode_is_locked(inode));
4199         trace_ext4_truncate_enter(inode);
4200
4201         if (!ext4_can_truncate(inode))
4202                 goto out_trace;
4203
4204         if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4205                 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4206
4207         if (ext4_has_inline_data(inode)) {
4208                 int has_inline = 1;
4209
4210                 err = ext4_inline_data_truncate(inode, &has_inline);
4211                 if (err || has_inline)
4212                         goto out_trace;
4213         }
4214
4215         /* If we zero-out tail of the page, we have to create jinode for jbd2 */
4216         if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4217                 if (ext4_inode_attach_jinode(inode) < 0)
4218                         goto out_trace;
4219         }
4220
4221         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4222                 credits = ext4_writepage_trans_blocks(inode);
4223         else
4224                 credits = ext4_blocks_for_truncate(inode);
4225
4226         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4227         if (IS_ERR(handle)) {
4228                 err = PTR_ERR(handle);
4229                 goto out_trace;
4230         }
4231
4232         if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4233                 ext4_block_truncate_page(handle, mapping, inode->i_size);
4234
4235         /*
4236          * We add the inode to the orphan list, so that if this
4237          * truncate spans multiple transactions, and we crash, we will
4238          * resume the truncate when the filesystem recovers.  It also
4239          * marks the inode dirty, to catch the new size.
4240          *
4241          * Implication: the file must always be in a sane, consistent
4242          * truncatable state while each transaction commits.
4243          */
4244         err = ext4_orphan_add(handle, inode);
4245         if (err)
4246                 goto out_stop;
4247
4248         down_write(&EXT4_I(inode)->i_data_sem);
4249
4250         ext4_discard_preallocations(inode, 0);
4251
4252         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4253                 err = ext4_ext_truncate(handle, inode);
4254         else
4255                 ext4_ind_truncate(handle, inode);
4256
4257         up_write(&ei->i_data_sem);
4258         if (err)
4259                 goto out_stop;
4260
4261         if (IS_SYNC(inode))
4262                 ext4_handle_sync(handle);
4263
4264 out_stop:
4265         /*
4266          * If this was a simple ftruncate() and the file will remain alive,
4267          * then we need to clear up the orphan record which we created above.
4268          * However, if this was a real unlink then we were called by
4269          * ext4_evict_inode(), and we allow that function to clean up the
4270          * orphan info for us.
4271          */
4272         if (inode->i_nlink)
4273                 ext4_orphan_del(handle, inode);
4274
4275         inode->i_mtime = inode->i_ctime = current_time(inode);
4276         err2 = ext4_mark_inode_dirty(handle, inode);
4277         if (unlikely(err2 && !err))
4278                 err = err2;
4279         ext4_journal_stop(handle);
4280
4281 out_trace:
4282         trace_ext4_truncate_exit(inode);
4283         return err;
4284 }
4285
4286 /*
4287  * ext4_get_inode_loc returns with an extra refcount against the inode's
4288  * underlying buffer_head on success. If 'in_mem' is true, we have all
4289  * data in memory that is needed to recreate the on-disk version of this
4290  * inode.
4291  */
4292 static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
4293                                 struct ext4_iloc *iloc, int in_mem,
4294                                 ext4_fsblk_t *ret_block)
4295 {
4296         struct ext4_group_desc  *gdp;
4297         struct buffer_head      *bh;
4298         ext4_fsblk_t            block;
4299         struct blk_plug         plug;
4300         int                     inodes_per_block, inode_offset;
4301
4302         iloc->bh = NULL;
4303         if (ino < EXT4_ROOT_INO ||
4304             ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4305                 return -EFSCORRUPTED;
4306
4307         iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
4308         gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4309         if (!gdp)
4310                 return -EIO;
4311
4312         /*
4313          * Figure out the offset within the block group inode table
4314          */
4315         inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4316         inode_offset = ((ino - 1) %
4317                         EXT4_INODES_PER_GROUP(sb));
4318         block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4319         iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4320
4321         bh = sb_getblk(sb, block);
4322         if (unlikely(!bh))
4323                 return -ENOMEM;
4324         if (ext4_simulate_fail(sb, EXT4_SIM_INODE_EIO))
4325                 goto simulate_eio;
4326         if (!buffer_uptodate(bh)) {
4327                 lock_buffer(bh);
4328
4329                 if (ext4_buffer_uptodate(bh)) {
4330                         /* someone brought it uptodate while we waited */
4331                         unlock_buffer(bh);
4332                         goto has_buffer;
4333                 }
4334
4335                 /*
4336                  * If we have all information of the inode in memory and this
4337                  * is the only valid inode in the block, we need not read the
4338                  * block.
4339                  */
4340                 if (in_mem) {
4341                         struct buffer_head *bitmap_bh;
4342                         int i, start;
4343
4344                         start = inode_offset & ~(inodes_per_block - 1);
4345
4346                         /* Is the inode bitmap in cache? */
4347                         bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4348                         if (unlikely(!bitmap_bh))
4349                                 goto make_io;
4350
4351                         /*
4352                          * If the inode bitmap isn't in cache then the
4353                          * optimisation may end up performing two reads instead
4354                          * of one, so skip it.
4355                          */
4356                         if (!buffer_uptodate(bitmap_bh)) {
4357                                 brelse(bitmap_bh);
4358                                 goto make_io;
4359                         }
4360                         for (i = start; i < start + inodes_per_block; i++) {
4361                                 if (i == inode_offset)
4362                                         continue;
4363                                 if (ext4_test_bit(i, bitmap_bh->b_data))
4364                                         break;
4365                         }
4366                         brelse(bitmap_bh);
4367                         if (i == start + inodes_per_block) {
4368                                 /* all other inodes are free, so skip I/O */
4369                                 memset(bh->b_data, 0, bh->b_size);
4370                                 set_buffer_uptodate(bh);
4371                                 unlock_buffer(bh);
4372                                 goto has_buffer;
4373                         }
4374                 }
4375
4376 make_io:
4377                 /*
4378                  * If we need to do any I/O, try to pre-readahead extra
4379                  * blocks from the inode table.
4380                  */
4381                 blk_start_plug(&plug);
4382                 if (EXT4_SB(sb)->s_inode_readahead_blks) {
4383                         ext4_fsblk_t b, end, table;
4384                         unsigned num;
4385                         __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4386
4387                         table = ext4_inode_table(sb, gdp);
4388                         /* s_inode_readahead_blks is always a power of 2 */
4389                         b = block & ~((ext4_fsblk_t) ra_blks - 1);
4390                         if (table > b)
4391                                 b = table;
4392                         end = b + ra_blks;
4393                         num = EXT4_INODES_PER_GROUP(sb);
4394                         if (ext4_has_group_desc_csum(sb))
4395                                 num -= ext4_itable_unused_count(sb, gdp);
4396                         table += num / inodes_per_block;
4397                         if (end > table)
4398                                 end = table;
4399                         while (b <= end)
4400                                 ext4_sb_breadahead_unmovable(sb, b++);
4401                 }
4402
4403                 /*
4404                  * There are other valid inodes in the buffer, this inode
4405                  * has in-inode xattrs, or we don't have this inode in memory.
4406                  * Read the block from disk.
4407                  */
4408                 trace_ext4_load_inode(sb, ino);
4409                 ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
4410                 blk_finish_plug(&plug);
4411                 wait_on_buffer(bh);
4412                 if (!buffer_uptodate(bh)) {
4413                 simulate_eio:
4414                         if (ret_block)
4415                                 *ret_block = block;
4416                         brelse(bh);
4417                         return -EIO;
4418                 }
4419         }
4420 has_buffer:
4421         iloc->bh = bh;
4422         return 0;
4423 }
4424
4425 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
4426                                         struct ext4_iloc *iloc)
4427 {
4428         ext4_fsblk_t err_blk;
4429         int ret;
4430
4431         ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, 0,
4432                                         &err_blk);
4433
4434         if (ret == -EIO)
4435                 ext4_error_inode_block(inode, err_blk, EIO,
4436                                         "unable to read itable block");
4437
4438         return ret;
4439 }
4440
4441 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4442 {
4443         ext4_fsblk_t err_blk;
4444         int ret;
4445
4446         /* We have all inode data except xattrs in memory here. */
4447         ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc,
4448                 !ext4_test_inode_state(inode, EXT4_STATE_XATTR), &err_blk);
4449
4450         if (ret == -EIO)
4451                 ext4_error_inode_block(inode, err_blk, EIO,
4452                                         "unable to read itable block");
4453
4454         return ret;
4455 }
4456
4457
4458 int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
4459                           struct ext4_iloc *iloc)
4460 {
4461         return __ext4_get_inode_loc(sb, ino, iloc, 0, NULL);
4462 }
4463
4464 static bool ext4_should_enable_dax(struct inode *inode)
4465 {
4466         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4467
4468         if (test_opt2(inode->i_sb, DAX_NEVER))
4469                 return false;
4470         if (!S_ISREG(inode->i_mode))
4471                 return false;
4472         if (ext4_should_journal_data(inode))
4473                 return false;
4474         if (ext4_has_inline_data(inode))
4475                 return false;
4476         if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
4477                 return false;
4478         if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
4479                 return false;
4480         if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4481                 return false;
4482         if (test_opt(inode->i_sb, DAX_ALWAYS))
4483                 return true;
4484
4485         return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
4486 }
4487
4488 void ext4_set_inode_flags(struct inode *inode, bool init)
4489 {
4490         unsigned int flags = EXT4_I(inode)->i_flags;
4491         unsigned int new_fl = 0;
4492
4493         WARN_ON_ONCE(IS_DAX(inode) && init);
4494
4495         if (flags & EXT4_SYNC_FL)
4496                 new_fl |= S_SYNC;
4497         if (flags & EXT4_APPEND_FL)
4498                 new_fl |= S_APPEND;
4499         if (flags & EXT4_IMMUTABLE_FL)
4500                 new_fl |= S_IMMUTABLE;
4501         if (flags & EXT4_NOATIME_FL)
4502                 new_fl |= S_NOATIME;
4503         if (flags & EXT4_DIRSYNC_FL)
4504                 new_fl |= S_DIRSYNC;
4505
4506         /* Because of the way inode_set_flags() works we must preserve S_DAX
4507          * here if already set. */
4508         new_fl |= (inode->i_flags & S_DAX);
4509         if (init && ext4_should_enable_dax(inode))
4510                 new_fl |= S_DAX;
4511
4512         if (flags & EXT4_ENCRYPT_FL)
4513                 new_fl |= S_ENCRYPTED;
4514         if (flags & EXT4_CASEFOLD_FL)
4515                 new_fl |= S_CASEFOLD;
4516         if (flags & EXT4_VERITY_FL)
4517                 new_fl |= S_VERITY;
4518         inode_set_flags(inode, new_fl,
4519                         S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4520                         S_ENCRYPTED|S_CASEFOLD|S_VERITY);
4521 }
4522
4523 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4524                                   struct ext4_inode_info *ei)
4525 {
4526         blkcnt_t i_blocks ;
4527         struct inode *inode = &(ei->vfs_inode);
4528         struct super_block *sb = inode->i_sb;
4529
4530         if (ext4_has_feature_huge_file(sb)) {
4531                 /* we are using combined 48 bit field */
4532                 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4533                                         le32_to_cpu(raw_inode->i_blocks_lo);
4534                 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4535                         /* i_blocks represent file system block size */
4536                         return i_blocks  << (inode->i_blkbits - 9);
4537                 } else {
4538                         return i_blocks;
4539                 }
4540         } else {
4541                 return le32_to_cpu(raw_inode->i_blocks_lo);
4542         }
4543 }
4544
4545 static inline int ext4_iget_extra_inode(struct inode *inode,
4546                                          struct ext4_inode *raw_inode,
4547                                          struct ext4_inode_info *ei)
4548 {
4549         __le32 *magic = (void *)raw_inode +
4550                         EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4551
4552         if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize + sizeof(__le32) <=
4553             EXT4_INODE_SIZE(inode->i_sb) &&
4554             *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4555                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4556                 return ext4_find_inline_data_nolock(inode);
4557         } else
4558                 EXT4_I(inode)->i_inline_off = 0;
4559         return 0;
4560 }
4561
4562 int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4563 {
4564         if (!ext4_has_feature_project(inode->i_sb))
4565                 return -EOPNOTSUPP;
4566         *projid = EXT4_I(inode)->i_projid;
4567         return 0;
4568 }
4569
4570 /*
4571  * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
4572  * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
4573  * set.
4574  */
4575 static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
4576 {
4577         if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4578                 inode_set_iversion_raw(inode, val);
4579         else
4580                 inode_set_iversion_queried(inode, val);
4581 }
4582 static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4583 {
4584         if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4585                 return inode_peek_iversion_raw(inode);
4586         else
4587                 return inode_peek_iversion(inode);
4588 }
4589
4590 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
4591                           ext4_iget_flags flags, const char *function,
4592                           unsigned int line)
4593 {
4594         struct ext4_iloc iloc;
4595         struct ext4_inode *raw_inode;
4596         struct ext4_inode_info *ei;
4597         struct inode *inode;
4598         journal_t *journal = EXT4_SB(sb)->s_journal;
4599         long ret;
4600         loff_t size;
4601         int block;
4602         uid_t i_uid;
4603         gid_t i_gid;
4604         projid_t i_projid;
4605
4606         if ((!(flags & EXT4_IGET_SPECIAL) &&
4607              (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)) ||
4608             (ino < EXT4_ROOT_INO) ||
4609             (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))) {
4610                 if (flags & EXT4_IGET_HANDLE)
4611                         return ERR_PTR(-ESTALE);
4612                 __ext4_error(sb, function, line, EFSCORRUPTED, 0,
4613                              "inode #%lu: comm %s: iget: illegal inode #",
4614                              ino, current->comm);
4615                 return ERR_PTR(-EFSCORRUPTED);
4616         }
4617
4618         inode = iget_locked(sb, ino);
4619         if (!inode)
4620                 return ERR_PTR(-ENOMEM);
4621         if (!(inode->i_state & I_NEW))
4622                 return inode;
4623
4624         ei = EXT4_I(inode);
4625         iloc.bh = NULL;
4626
4627         ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
4628         if (ret < 0)
4629                 goto bad_inode;
4630         raw_inode = ext4_raw_inode(&iloc);
4631
4632         if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) {
4633                 ext4_error_inode(inode, function, line, 0,
4634                                  "iget: root inode unallocated");
4635                 ret = -EFSCORRUPTED;
4636                 goto bad_inode;
4637         }
4638
4639         if ((flags & EXT4_IGET_HANDLE) &&
4640             (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
4641                 ret = -ESTALE;
4642                 goto bad_inode;
4643         }
4644
4645         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4646                 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4647                 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4648                         EXT4_INODE_SIZE(inode->i_sb) ||
4649                     (ei->i_extra_isize & 3)) {
4650                         ext4_error_inode(inode, function, line, 0,
4651                                          "iget: bad extra_isize %u "
4652                                          "(inode size %u)",
4653                                          ei->i_extra_isize,
4654                                          EXT4_INODE_SIZE(inode->i_sb));
4655                         ret = -EFSCORRUPTED;
4656                         goto bad_inode;
4657                 }
4658         } else
4659                 ei->i_extra_isize = 0;
4660
4661         /* Precompute checksum seed for inode metadata */
4662         if (ext4_has_metadata_csum(sb)) {
4663                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4664                 __u32 csum;
4665                 __le32 inum = cpu_to_le32(inode->i_ino);
4666                 __le32 gen = raw_inode->i_generation;
4667                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4668                                    sizeof(inum));
4669                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4670                                               sizeof(gen));
4671         }
4672
4673         if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
4674             ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
4675              (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
4676                 ext4_error_inode_err(inode, function, line, 0,
4677                                 EFSBADCRC, "iget: checksum invalid");
4678                 ret = -EFSBADCRC;
4679                 goto bad_inode;
4680         }
4681
4682         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4683         i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4684         i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4685         if (ext4_has_feature_project(sb) &&
4686             EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4687             EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4688                 i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4689         else
4690                 i_projid = EXT4_DEF_PROJID;
4691
4692         if (!(test_opt(inode->i_sb, NO_UID32))) {
4693                 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4694                 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4695         }
4696         i_uid_write(inode, i_uid);
4697         i_gid_write(inode, i_gid);
4698         ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4699         set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4700
4701         ext4_clear_state_flags(ei);     /* Only relevant on 32-bit archs */
4702         ei->i_inline_off = 0;
4703         ei->i_dir_start_lookup = 0;
4704         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4705         /* We now have enough fields to check if the inode was active or not.
4706          * This is needed because nfsd might try to access dead inodes
4707          * the test is that same one that e2fsck uses
4708          * NeilBrown 1999oct15
4709          */
4710         if (inode->i_nlink == 0) {
4711                 if ((inode->i_mode == 0 ||
4712                      !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4713                     ino != EXT4_BOOT_LOADER_INO) {
4714                         /* this inode is deleted */
4715                         ret = -ESTALE;
4716                         goto bad_inode;
4717                 }
4718                 /* The only unlinked inodes we let through here have
4719                  * valid i_mode and are being read by the orphan
4720                  * recovery code: that's fine, we're about to complete
4721                  * the process of deleting those.
4722                  * OR it is the EXT4_BOOT_LOADER_INO which is
4723                  * not initialized on a new filesystem. */
4724         }
4725         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4726         ext4_set_inode_flags(inode, true);
4727         inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4728         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4729         if (ext4_has_feature_64bit(sb))
4730                 ei->i_file_acl |=
4731                         ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4732         inode->i_size = ext4_isize(sb, raw_inode);
4733         if ((size = i_size_read(inode)) < 0) {
4734                 ext4_error_inode(inode, function, line, 0,
4735                                  "iget: bad i_size value: %lld", size);
4736                 ret = -EFSCORRUPTED;
4737                 goto bad_inode;
4738         }
4739         /*
4740          * If dir_index is not enabled but there's dir with INDEX flag set,
4741          * we'd normally treat htree data as empty space. But with metadata
4742          * checksumming that corrupts checksums so forbid that.
4743          */
4744         if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
4745             ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
4746                 ext4_error_inode(inode, function, line, 0,
4747                          "iget: Dir with htree data on filesystem without dir_index feature.");
4748                 ret = -EFSCORRUPTED;
4749                 goto bad_inode;
4750         }
4751         ei->i_disksize = inode->i_size;
4752 #ifdef CONFIG_QUOTA
4753         ei->i_reserved_quota = 0;
4754 #endif
4755         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4756         ei->i_block_group = iloc.block_group;
4757         ei->i_last_alloc_group = ~0;
4758         /*
4759          * NOTE! The in-memory inode i_data array is in little-endian order
4760          * even on big-endian machines: we do NOT byteswap the block numbers!
4761          */
4762         for (block = 0; block < EXT4_N_BLOCKS; block++)
4763                 ei->i_data[block] = raw_inode->i_block[block];
4764         INIT_LIST_HEAD(&ei->i_orphan);
4765         ext4_fc_init_inode(&ei->vfs_inode);
4766
4767         /*
4768          * Set transaction id's of transactions that have to be committed
4769          * to finish f[data]sync. We set them to currently running transaction
4770          * as we cannot be sure that the inode or some of its metadata isn't
4771          * part of the transaction - the inode could have been reclaimed and
4772          * now it is reread from disk.
4773          */
4774         if (journal) {
4775                 transaction_t *transaction;
4776                 tid_t tid;
4777
4778                 read_lock(&journal->j_state_lock);
4779                 if (journal->j_running_transaction)
4780                         transaction = journal->j_running_transaction;
4781                 else
4782                         transaction = journal->j_committing_transaction;
4783                 if (transaction)
4784                         tid = transaction->t_tid;
4785                 else
4786                         tid = journal->j_commit_sequence;
4787                 read_unlock(&journal->j_state_lock);
4788                 ei->i_sync_tid = tid;
4789                 ei->i_datasync_tid = tid;
4790         }
4791
4792         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4793                 if (ei->i_extra_isize == 0) {
4794                         /* The extra space is currently unused. Use it. */
4795                         BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4796                         ei->i_extra_isize = sizeof(struct ext4_inode) -
4797                                             EXT4_GOOD_OLD_INODE_SIZE;
4798                 } else {
4799                         ret = ext4_iget_extra_inode(inode, raw_inode, ei);
4800                         if (ret)
4801                                 goto bad_inode;
4802                 }
4803         }
4804
4805         EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4806         EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4807         EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4808         EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4809
4810         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4811                 u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4812
4813                 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4814                         if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4815                                 ivers |=
4816                     (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4817                 }
4818                 ext4_inode_set_iversion_queried(inode, ivers);
4819         }
4820
4821         ret = 0;
4822         if (ei->i_file_acl &&
4823             !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
4824                 ext4_error_inode(inode, function, line, 0,
4825                                  "iget: bad extended attribute block %llu",
4826                                  ei->i_file_acl);
4827                 ret = -EFSCORRUPTED;
4828                 goto bad_inode;
4829         } else if (!ext4_has_inline_data(inode)) {
4830                 /* validate the block references in the inode */
4831                 if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
4832                         (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4833                         (S_ISLNK(inode->i_mode) &&
4834                         !ext4_inode_is_fast_symlink(inode)))) {
4835                         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4836                                 ret = ext4_ext_check_inode(inode);
4837                         else
4838                                 ret = ext4_ind_check_inode(inode);
4839                 }
4840         }
4841         if (ret)
4842                 goto bad_inode;
4843
4844         if (S_ISREG(inode->i_mode)) {
4845                 inode->i_op = &ext4_file_inode_operations;
4846                 inode->i_fop = &ext4_file_operations;
4847                 ext4_set_aops(inode);
4848         } else if (S_ISDIR(inode->i_mode)) {
4849                 inode->i_op = &ext4_dir_inode_operations;
4850                 inode->i_fop = &ext4_dir_operations;
4851         } else if (S_ISLNK(inode->i_mode)) {
4852                 /* VFS does not allow setting these so must be corruption */
4853                 if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
4854                         ext4_error_inode(inode, function, line, 0,
4855                                          "iget: immutable or append flags "
4856                                          "not allowed on symlinks");
4857                         ret = -EFSCORRUPTED;
4858                         goto bad_inode;
4859                 }
4860                 if (IS_ENCRYPTED(inode)) {
4861                         inode->i_op = &ext4_encrypted_symlink_inode_operations;
4862                         ext4_set_aops(inode);
4863                 } else if (ext4_inode_is_fast_symlink(inode)) {
4864                         inode->i_link = (char *)ei->i_data;
4865                         inode->i_op = &ext4_fast_symlink_inode_operations;
4866                         nd_terminate_link(ei->i_data, inode->i_size,
4867                                 sizeof(ei->i_data) - 1);
4868                 } else {
4869                         inode->i_op = &ext4_symlink_inode_operations;
4870                         ext4_set_aops(inode);
4871                 }
4872                 inode_nohighmem(inode);
4873         } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4874               S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4875                 inode->i_op = &ext4_special_inode_operations;
4876                 if (raw_inode->i_block[0])
4877                         init_special_inode(inode, inode->i_mode,
4878                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4879                 else
4880                         init_special_inode(inode, inode->i_mode,
4881                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4882         } else if (ino == EXT4_BOOT_LOADER_INO) {
4883                 make_bad_inode(inode);
4884         } else {
4885                 ret = -EFSCORRUPTED;
4886                 ext4_error_inode(inode, function, line, 0,
4887                                  "iget: bogus i_mode (%o)", inode->i_mode);
4888                 goto bad_inode;
4889         }
4890         if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb))
4891                 ext4_error_inode(inode, function, line, 0,
4892                                  "casefold flag without casefold feature");
4893         brelse(iloc.bh);
4894
4895         unlock_new_inode(inode);
4896         return inode;
4897
4898 bad_inode:
4899         brelse(iloc.bh);
4900         iget_failed(inode);
4901         return ERR_PTR(ret);
4902 }
4903
4904 static int ext4_inode_blocks_set(handle_t *handle,
4905                                 struct ext4_inode *raw_inode,
4906                                 struct ext4_inode_info *ei)
4907 {
4908         struct inode *inode = &(ei->vfs_inode);
4909         u64 i_blocks = READ_ONCE(inode->i_blocks);
4910         struct super_block *sb = inode->i_sb;
4911
4912         if (i_blocks <= ~0U) {
4913                 /*
4914                  * i_blocks can be represented in a 32 bit variable
4915                  * as multiple of 512 bytes
4916                  */
4917                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4918                 raw_inode->i_blocks_high = 0;
4919                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4920                 return 0;
4921         }
4922         if (!ext4_has_feature_huge_file(sb))
4923                 return -EFBIG;
4924
4925         if (i_blocks <= 0xffffffffffffULL) {
4926                 /*
4927                  * i_blocks can be represented in a 48 bit variable
4928                  * as multiple of 512 bytes
4929                  */
4930                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4931                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4932                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4933         } else {
4934                 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4935                 /* i_block is stored in file system block size */
4936                 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4937                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4938                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4939         }
4940         return 0;
4941 }
4942
4943 static void __ext4_update_other_inode_time(struct super_block *sb,
4944                                            unsigned long orig_ino,
4945                                            unsigned long ino,
4946                                            struct ext4_inode *raw_inode)
4947 {
4948         struct inode *inode;
4949
4950         inode = find_inode_by_ino_rcu(sb, ino);
4951         if (!inode)
4952                 return;
4953
4954         if ((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4955                                I_DIRTY_INODE)) ||
4956             ((inode->i_state & I_DIRTY_TIME) == 0))
4957                 return;
4958
4959         spin_lock(&inode->i_lock);
4960         if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4961                                 I_DIRTY_INODE)) == 0) &&
4962             (inode->i_state & I_DIRTY_TIME)) {
4963                 struct ext4_inode_info  *ei = EXT4_I(inode);
4964
4965                 inode->i_state &= ~I_DIRTY_TIME;
4966                 spin_unlock(&inode->i_lock);
4967
4968                 spin_lock(&ei->i_raw_lock);
4969                 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4970                 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4971                 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4972                 ext4_inode_csum_set(inode, raw_inode, ei);
4973                 spin_unlock(&ei->i_raw_lock);
4974                 trace_ext4_other_inode_update_time(inode, orig_ino);
4975                 return;
4976         }
4977         spin_unlock(&inode->i_lock);
4978 }
4979
4980 /*
4981  * Opportunistically update the other time fields for other inodes in
4982  * the same inode table block.
4983  */
4984 static void ext4_update_other_inodes_time(struct super_block *sb,
4985                                           unsigned long orig_ino, char *buf)
4986 {
4987         unsigned long ino;
4988         int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4989         int inode_size = EXT4_INODE_SIZE(sb);
4990
4991         /*
4992          * Calculate the first inode in the inode table block.  Inode
4993          * numbers are one-based.  That is, the first inode in a block
4994          * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
4995          */
4996         ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
4997         rcu_read_lock();
4998         for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
4999                 if (ino == orig_ino)
5000                         continue;
5001                 __ext4_update_other_inode_time(sb, orig_ino, ino,
5002                                                (struct ext4_inode *)buf);
5003         }
5004         rcu_read_unlock();
5005 }
5006
5007 /*
5008  * Post the struct inode info into an on-disk inode location in the
5009  * buffer-cache.  This gobbles the caller's reference to the
5010  * buffer_head in the inode location struct.
5011  *
5012  * The caller must have write access to iloc->bh.
5013  */
5014 static int ext4_do_update_inode(handle_t *handle,
5015                                 struct inode *inode,
5016                                 struct ext4_iloc *iloc)
5017 {
5018         struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5019         struct ext4_inode_info *ei = EXT4_I(inode);
5020         struct buffer_head *bh = iloc->bh;
5021         struct super_block *sb = inode->i_sb;
5022         int err = 0, rc, block;
5023         int need_datasync = 0, set_large_file = 0;
5024         uid_t i_uid;
5025         gid_t i_gid;
5026         projid_t i_projid;
5027
5028         spin_lock(&ei->i_raw_lock);
5029
5030         /* For fields not tracked in the in-memory inode,
5031          * initialise them to zero for new inodes. */
5032         if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5033                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5034
5035         err = ext4_inode_blocks_set(handle, raw_inode, ei);
5036         if (err) {
5037                 spin_unlock(&ei->i_raw_lock);
5038                 goto out_brelse;
5039         }
5040
5041         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
5042         i_uid = i_uid_read(inode);
5043         i_gid = i_gid_read(inode);
5044         i_projid = from_kprojid(&init_user_ns, ei->i_projid);
5045         if (!(test_opt(inode->i_sb, NO_UID32))) {
5046                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
5047                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
5048 /*
5049  * Fix up interoperability with old kernels. Otherwise, old inodes get
5050  * re-used with the upper 16 bits of the uid/gid intact
5051  */
5052                 if (ei->i_dtime && list_empty(&ei->i_orphan)) {
5053                         raw_inode->i_uid_high = 0;
5054                         raw_inode->i_gid_high = 0;
5055                 } else {
5056                         raw_inode->i_uid_high =
5057                                 cpu_to_le16(high_16_bits(i_uid));
5058                         raw_inode->i_gid_high =
5059                                 cpu_to_le16(high_16_bits(i_gid));
5060                 }
5061         } else {
5062                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
5063                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
5064                 raw_inode->i_uid_high = 0;
5065                 raw_inode->i_gid_high = 0;
5066         }
5067         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5068
5069         EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5070         EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5071         EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5072         EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5073
5074         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5075         raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
5076         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
5077                 raw_inode->i_file_acl_high =
5078                         cpu_to_le16(ei->i_file_acl >> 32);
5079         raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5080         if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode)) {
5081                 ext4_isize_set(raw_inode, ei->i_disksize);
5082                 need_datasync = 1;
5083         }
5084         if (ei->i_disksize > 0x7fffffffULL) {
5085                 if (!ext4_has_feature_large_file(sb) ||
5086                                 EXT4_SB(sb)->s_es->s_rev_level ==
5087                     cpu_to_le32(EXT4_GOOD_OLD_REV))
5088                         set_large_file = 1;
5089         }
5090         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5091         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5092                 if (old_valid_dev(inode->i_rdev)) {
5093                         raw_inode->i_block[0] =
5094                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
5095                         raw_inode->i_block[1] = 0;
5096                 } else {
5097                         raw_inode->i_block[0] = 0;
5098                         raw_inode->i_block[1] =
5099                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
5100                         raw_inode->i_block[2] = 0;
5101                 }
5102         } else if (!ext4_has_inline_data(inode)) {
5103                 for (block = 0; block < EXT4_N_BLOCKS; block++)
5104                         raw_inode->i_block[block] = ei->i_data[block];
5105         }
5106
5107         if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
5108                 u64 ivers = ext4_inode_peek_iversion(inode);
5109
5110                 raw_inode->i_disk_version = cpu_to_le32(ivers);
5111                 if (ei->i_extra_isize) {
5112                         if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5113                                 raw_inode->i_version_hi =
5114                                         cpu_to_le32(ivers >> 32);
5115                         raw_inode->i_extra_isize =
5116                                 cpu_to_le16(ei->i_extra_isize);
5117                 }
5118         }
5119
5120         BUG_ON(!ext4_has_feature_project(inode->i_sb) &&
5121                i_projid != EXT4_DEF_PROJID);
5122
5123         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
5124             EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
5125                 raw_inode->i_projid = cpu_to_le32(i_projid);
5126
5127         ext4_inode_csum_set(inode, raw_inode, ei);
5128         spin_unlock(&ei->i_raw_lock);
5129         if (inode->i_sb->s_flags & SB_LAZYTIME)
5130                 ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5131                                               bh->b_data);
5132
5133         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5134         rc = ext4_handle_dirty_metadata(handle, NULL, bh);
5135         if (!err)
5136                 err = rc;
5137         ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5138         if (set_large_file) {
5139                 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5140                 err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
5141                 if (err)
5142                         goto out_brelse;
5143                 ext4_set_feature_large_file(sb);
5144                 ext4_handle_sync(handle);
5145                 err = ext4_handle_dirty_super(handle, sb);
5146         }
5147         ext4_update_inode_fsync_trans(handle, inode, need_datasync);
5148 out_brelse:
5149         brelse(bh);
5150         ext4_std_error(inode->i_sb, err);
5151         return err;
5152 }
5153
5154 /*
5155  * ext4_write_inode()
5156  *
5157  * We are called from a few places:
5158  *
5159  * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5160  *   Here, there will be no transaction running. We wait for any running
5161  *   transaction to commit.
5162  *
5163  * - Within flush work (sys_sync(), kupdate and such).
5164  *   We wait on commit, if told to.
5165  *
5166  * - Within iput_final() -> write_inode_now()
5167  *   We wait on commit, if told to.
5168  *
5169  * In all cases it is actually safe for us to return without doing anything,
5170  * because the inode has been copied into a raw inode buffer in
5171  * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5172  * writeback.
5173  *
5174  * Note that we are absolutely dependent upon all inode dirtiers doing the
5175  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5176  * which we are interested.
5177  *
5178  * It would be a bug for them to not do this.  The code:
5179  *
5180  *      mark_inode_dirty(inode)
5181  *      stuff();
5182  *      inode->i_size = expr;
5183  *
5184  * is in error because write_inode() could occur while `stuff()' is running,
5185  * and the new i_size will be lost.  Plus the inode will no longer be on the
5186  * superblock's dirty inode list.
5187  */
5188 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5189 {
5190         int err;
5191
5192         if (WARN_ON_ONCE(current->flags & PF_MEMALLOC) ||
5193             sb_rdonly(inode->i_sb))
5194                 return 0;
5195
5196         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5197                 return -EIO;
5198
5199         if (EXT4_SB(inode->i_sb)->s_journal) {
5200                 if (ext4_journal_current_handle()) {
5201                         jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5202                         dump_stack();
5203                         return -EIO;
5204                 }
5205
5206                 /*
5207                  * No need to force transaction in WB_SYNC_NONE mode. Also
5208                  * ext4_sync_fs() will force the commit after everything is
5209                  * written.
5210                  */
5211                 if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5212                         return 0;
5213
5214                 err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
5215                                                 EXT4_I(inode)->i_sync_tid);
5216         } else {
5217                 struct ext4_iloc iloc;
5218
5219                 err = __ext4_get_inode_loc_noinmem(inode, &iloc);
5220                 if (err)
5221                         return err;
5222                 /*
5223                  * sync(2) will flush the whole buffer cache. No need to do
5224                  * it here separately for each inode.
5225                  */
5226                 if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5227                         sync_dirty_buffer(iloc.bh);
5228                 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5229                         ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5230                                                "IO error syncing inode");
5231                         err = -EIO;
5232                 }
5233                 brelse(iloc.bh);
5234         }
5235         return err;
5236 }
5237
5238 /*
5239  * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
5240  * buffers that are attached to a page stradding i_size and are undergoing
5241  * commit. In that case we have to wait for commit to finish and try again.
5242  */
5243 static void ext4_wait_for_tail_page_commit(struct inode *inode)
5244 {
5245         struct page *page;
5246         unsigned offset;
5247         journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5248         tid_t commit_tid = 0;
5249         int ret;
5250
5251         offset = inode->i_size & (PAGE_SIZE - 1);
5252         /*
5253          * If the page is fully truncated, we don't need to wait for any commit
5254          * (and we even should not as __ext4_journalled_invalidatepage() may
5255          * strip all buffers from the page but keep the page dirty which can then
5256          * confuse e.g. concurrent ext4_writepage() seeing dirty page without
5257          * buffers). Also we don't need to wait for any commit if all buffers in
5258          * the page remain valid. This is most beneficial for the common case of
5259          * blocksize == PAGESIZE.
5260          */
5261         if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
5262                 return;
5263         while (1) {
5264                 page = find_lock_page(inode->i_mapping,
5265                                       inode->i_size >> PAGE_SHIFT);
5266                 if (!page)
5267                         return;
5268                 ret = __ext4_journalled_invalidatepage(page, offset,
5269                                                 PAGE_SIZE - offset);
5270                 unlock_page(page);
5271                 put_page(page);
5272                 if (ret != -EBUSY)
5273                         return;
5274                 commit_tid = 0;
5275                 read_lock(&journal->j_state_lock);
5276                 if (journal->j_committing_transaction)
5277                         commit_tid = journal->j_committing_transaction->t_tid;
5278                 read_unlock(&journal->j_state_lock);
5279                 if (commit_tid)
5280                         jbd2_log_wait_commit(journal, commit_tid);
5281         }
5282 }
5283
5284 /*
5285  * ext4_setattr()
5286  *
5287  * Called from notify_change.
5288  *
5289  * We want to trap VFS attempts to truncate the file as soon as
5290  * possible.  In particular, we want to make sure that when the VFS
5291  * shrinks i_size, we put the inode on the orphan list and modify
5292  * i_disksize immediately, so that during the subsequent flushing of
5293  * dirty pages and freeing of disk blocks, we can guarantee that any
5294  * commit will leave the blocks being flushed in an unused state on
5295  * disk.  (On recovery, the inode will get truncated and the blocks will
5296  * be freed, so we have a strong guarantee that no future commit will
5297  * leave these blocks visible to the user.)
5298  *
5299  * Another thing we have to assure is that if we are in ordered mode
5300  * and inode is still attached to the committing transaction, we must
5301  * we start writeout of all the dirty pages which are being truncated.
5302  * This way we are sure that all the data written in the previous
5303  * transaction are already on disk (truncate waits for pages under
5304  * writeback).
5305  *
5306  * Called with inode->i_mutex down.
5307  */
5308 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
5309 {
5310         struct inode *inode = d_inode(dentry);
5311         int error, rc = 0;
5312         int orphan = 0;
5313         const unsigned int ia_valid = attr->ia_valid;
5314
5315         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5316                 return -EIO;
5317
5318         if (unlikely(IS_IMMUTABLE(inode)))
5319                 return -EPERM;
5320
5321         if (unlikely(IS_APPEND(inode) &&
5322                      (ia_valid & (ATTR_MODE | ATTR_UID |
5323                                   ATTR_GID | ATTR_TIMES_SET))))
5324                 return -EPERM;
5325
5326         error = setattr_prepare(dentry, attr);
5327         if (error)
5328                 return error;
5329
5330         error = fscrypt_prepare_setattr(dentry, attr);
5331         if (error)
5332                 return error;
5333
5334         error = fsverity_prepare_setattr(dentry, attr);
5335         if (error)
5336                 return error;
5337
5338         if (is_quota_modification(inode, attr)) {
5339                 error = dquot_initialize(inode);
5340                 if (error)
5341                         return error;
5342         }
5343         ext4_fc_start_update(inode);
5344         if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
5345             (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
5346                 handle_t *handle;
5347
5348                 /* (user+group)*(old+new) structure, inode write (sb,
5349                  * inode block, ? - but truncate inode update has it) */
5350                 handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5351                         (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5352                          EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5353                 if (IS_ERR(handle)) {
5354                         error = PTR_ERR(handle);
5355                         goto err_out;
5356                 }
5357
5358                 /* dquot_transfer() calls back ext4_get_inode_usage() which
5359                  * counts xattr inode references.
5360                  */
5361                 down_read(&EXT4_I(inode)->xattr_sem);
5362                 error = dquot_transfer(inode, attr);
5363                 up_read(&EXT4_I(inode)->xattr_sem);
5364
5365                 if (error) {
5366                         ext4_journal_stop(handle);
5367                         ext4_fc_stop_update(inode);
5368                         return error;
5369                 }
5370                 /* Update corresponding info in inode so that everything is in
5371                  * one transaction */
5372                 if (attr->ia_valid & ATTR_UID)
5373                         inode->i_uid = attr->ia_uid;
5374                 if (attr->ia_valid & ATTR_GID)
5375                         inode->i_gid = attr->ia_gid;
5376                 error = ext4_mark_inode_dirty(handle, inode);
5377                 ext4_journal_stop(handle);
5378                 if (unlikely(error))
5379                         return error;
5380         }
5381
5382         if (attr->ia_valid & ATTR_SIZE) {
5383                 handle_t *handle;
5384                 loff_t oldsize = inode->i_size;
5385                 int shrink = (attr->ia_size < inode->i_size);
5386
5387                 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5388                         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5389
5390                         if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5391                                 ext4_fc_stop_update(inode);
5392                                 return -EFBIG;
5393                         }
5394                 }
5395                 if (!S_ISREG(inode->i_mode)) {
5396                         ext4_fc_stop_update(inode);
5397                         return -EINVAL;
5398                 }
5399
5400                 if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5401                         inode_inc_iversion(inode);
5402
5403                 if (shrink) {
5404                         if (ext4_should_order_data(inode)) {
5405                                 error = ext4_begin_ordered_truncate(inode,
5406                                                             attr->ia_size);
5407                                 if (error)
5408                                         goto err_out;
5409                         }
5410                         /*
5411                          * Blocks are going to be removed from the inode. Wait
5412                          * for dio in flight.
5413                          */
5414                         inode_dio_wait(inode);
5415                 }
5416
5417                 down_write(&EXT4_I(inode)->i_mmap_sem);
5418
5419                 rc = ext4_break_layouts(inode);
5420                 if (rc) {
5421                         up_write(&EXT4_I(inode)->i_mmap_sem);
5422                         goto err_out;
5423                 }
5424
5425                 if (attr->ia_size != inode->i_size) {
5426                         handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5427                         if (IS_ERR(handle)) {
5428                                 error = PTR_ERR(handle);
5429                                 goto out_mmap_sem;
5430                         }
5431                         if (ext4_handle_valid(handle) && shrink) {
5432                                 error = ext4_orphan_add(handle, inode);
5433                                 orphan = 1;
5434                         }
5435                         /*
5436                          * Update c/mtime on truncate up, ext4_truncate() will
5437                          * update c/mtime in shrink case below
5438                          */
5439                         if (!shrink) {
5440                                 inode->i_mtime = current_time(inode);
5441                                 inode->i_ctime = inode->i_mtime;
5442                         }
5443
5444                         if (shrink)
5445                                 ext4_fc_track_range(inode,
5446                                         (attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5447                                         inode->i_sb->s_blocksize_bits,
5448                                         (oldsize > 0 ? oldsize - 1 : 0) >>
5449                                         inode->i_sb->s_blocksize_bits);
5450                         else
5451                                 ext4_fc_track_range(
5452                                         inode,
5453                                         (oldsize > 0 ? oldsize - 1 : oldsize) >>
5454                                         inode->i_sb->s_blocksize_bits,
5455                                         (attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5456                                         inode->i_sb->s_blocksize_bits);
5457
5458                         down_write(&EXT4_I(inode)->i_data_sem);
5459                         EXT4_I(inode)->i_disksize = attr->ia_size;
5460                         rc = ext4_mark_inode_dirty(handle, inode);
5461                         if (!error)
5462                                 error = rc;
5463                         /*
5464                          * We have to update i_size under i_data_sem together
5465                          * with i_disksize to avoid races with writeback code
5466                          * running ext4_wb_update_i_disksize().
5467                          */
5468                         if (!error)
5469                                 i_size_write(inode, attr->ia_size);
5470                         up_write(&EXT4_I(inode)->i_data_sem);
5471                         ext4_journal_stop(handle);
5472                         if (error)
5473                                 goto out_mmap_sem;
5474                         if (!shrink) {
5475                                 pagecache_isize_extended(inode, oldsize,
5476                                                          inode->i_size);
5477                         } else if (ext4_should_journal_data(inode)) {
5478                                 ext4_wait_for_tail_page_commit(inode);
5479                         }
5480                 }
5481
5482                 /*
5483                  * Truncate pagecache after we've waited for commit
5484                  * in data=journal mode to make pages freeable.
5485                  */
5486                 truncate_pagecache(inode, inode->i_size);
5487                 /*
5488                  * Call ext4_truncate() even if i_size didn't change to
5489                  * truncate possible preallocated blocks.
5490                  */
5491                 if (attr->ia_size <= oldsize) {
5492                         rc = ext4_truncate(inode);
5493                         if (rc)
5494                                 error = rc;
5495                 }
5496 out_mmap_sem:
5497                 up_write(&EXT4_I(inode)->i_mmap_sem);
5498         }
5499
5500         if (!error) {
5501                 setattr_copy(inode, attr);
5502                 mark_inode_dirty(inode);
5503         }
5504
5505         /*
5506          * If the call to ext4_truncate failed to get a transaction handle at
5507          * all, we need to clean up the in-core orphan list manually.
5508          */
5509         if (orphan && inode->i_nlink)
5510                 ext4_orphan_del(NULL, inode);
5511
5512         if (!error && (ia_valid & ATTR_MODE))
5513                 rc = posix_acl_chmod(inode, inode->i_mode);
5514
5515 err_out:
5516         if  (error)
5517                 ext4_std_error(inode->i_sb, error);
5518         if (!error)
5519                 error = rc;
5520         ext4_fc_stop_update(inode);
5521         return error;
5522 }
5523
5524 int ext4_getattr(const struct path *path, struct kstat *stat,
5525                  u32 request_mask, unsigned int query_flags)
5526 {
5527         struct inode *inode = d_inode(path->dentry);
5528         struct ext4_inode *raw_inode;
5529         struct ext4_inode_info *ei = EXT4_I(inode);
5530         unsigned int flags;
5531
5532         if ((request_mask & STATX_BTIME) &&
5533             EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
5534                 stat->result_mask |= STATX_BTIME;
5535                 stat->btime.tv_sec = ei->i_crtime.tv_sec;
5536                 stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5537         }
5538
5539         flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5540         if (flags & EXT4_APPEND_FL)
5541                 stat->attributes |= STATX_ATTR_APPEND;
5542         if (flags & EXT4_COMPR_FL)
5543                 stat->attributes |= STATX_ATTR_COMPRESSED;
5544         if (flags & EXT4_ENCRYPT_FL)
5545                 stat->attributes |= STATX_ATTR_ENCRYPTED;
5546         if (flags & EXT4_IMMUTABLE_FL)
5547                 stat->attributes |= STATX_ATTR_IMMUTABLE;
5548         if (flags & EXT4_NODUMP_FL)
5549                 stat->attributes |= STATX_ATTR_NODUMP;
5550         if (flags & EXT4_VERITY_FL)
5551                 stat->attributes |= STATX_ATTR_VERITY;
5552
5553         stat->attributes_mask |= (STATX_ATTR_APPEND |
5554                                   STATX_ATTR_COMPRESSED |
5555                                   STATX_ATTR_ENCRYPTED |
5556                                   STATX_ATTR_IMMUTABLE |
5557                                   STATX_ATTR_NODUMP |
5558                                   STATX_ATTR_VERITY);
5559
5560         generic_fillattr(inode, stat);
5561         return 0;
5562 }
5563
5564 int ext4_file_getattr(const struct path *path, struct kstat *stat,
5565                       u32 request_mask, unsigned int query_flags)
5566 {
5567         struct inode *inode = d_inode(path->dentry);
5568         u64 delalloc_blocks;
5569
5570         ext4_getattr(path, stat, request_mask, query_flags);
5571
5572         /*
5573          * If there is inline data in the inode, the inode will normally not
5574          * have data blocks allocated (it may have an external xattr block).
5575          * Report at least one sector for such files, so tools like tar, rsync,
5576          * others don't incorrectly think the file is completely sparse.
5577          */
5578         if (unlikely(ext4_has_inline_data(inode)))
5579                 stat->blocks += (stat->size + 511) >> 9;
5580
5581         /*
5582          * We can't update i_blocks if the block allocation is delayed
5583          * otherwise in the case of system crash before the real block
5584          * allocation is done, we will have i_blocks inconsistent with
5585          * on-disk file blocks.
5586          * We always keep i_blocks updated together with real
5587          * allocation. But to not confuse with user, stat
5588          * will return the blocks that include the delayed allocation
5589          * blocks for this file.
5590          */
5591         delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5592                                    EXT4_I(inode)->i_reserved_data_blocks);
5593         stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5594         return 0;
5595 }
5596
5597 static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5598                                    int pextents)
5599 {
5600         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5601                 return ext4_ind_trans_blocks(inode, lblocks);
5602         return ext4_ext_index_trans_blocks(inode, pextents);
5603 }
5604
5605 /*
5606  * Account for index blocks, block groups bitmaps and block group
5607  * descriptor blocks if modify datablocks and index blocks
5608  * worse case, the indexs blocks spread over different block groups
5609  *
5610  * If datablocks are discontiguous, they are possible to spread over
5611  * different block groups too. If they are contiguous, with flexbg,
5612  * they could still across block group boundary.
5613  *
5614  * Also account for superblock, inode, quota and xattr blocks
5615  */
5616 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5617                                   int pextents)
5618 {
5619         ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5620         int gdpblocks;
5621         int idxblocks;
5622         int ret = 0;
5623
5624         /*
5625          * How many index blocks need to touch to map @lblocks logical blocks
5626          * to @pextents physical extents?
5627          */
5628         idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5629
5630         ret = idxblocks;
5631
5632         /*
5633          * Now let's see how many group bitmaps and group descriptors need
5634          * to account
5635          */
5636         groups = idxblocks + pextents;
5637         gdpblocks = groups;
5638         if (groups > ngroups)
5639                 groups = ngroups;
5640         if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5641                 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5642
5643         /* bitmaps and block group descriptor blocks */
5644         ret += groups + gdpblocks;
5645
5646         /* Blocks for super block, inode, quota and xattr blocks */
5647         ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5648
5649         return ret;
5650 }
5651
5652 /*
5653  * Calculate the total number of credits to reserve to fit
5654  * the modification of a single pages into a single transaction,
5655  * which may include multiple chunks of block allocations.
5656  *
5657  * This could be called via ext4_write_begin()
5658  *
5659  * We need to consider the worse case, when
5660  * one new block per extent.
5661  */
5662 int ext4_writepage_trans_blocks(struct inode *inode)
5663 {
5664         int bpp = ext4_journal_blocks_per_page(inode);
5665         int ret;
5666
5667         ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5668
5669         /* Account for data blocks for journalled mode */
5670         if (ext4_should_journal_data(inode))
5671                 ret += bpp;
5672         return ret;
5673 }
5674
5675 /*
5676  * Calculate the journal credits for a chunk of data modification.
5677  *
5678  * This is called from DIO, fallocate or whoever calling
5679  * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5680  *
5681  * journal buffers for data blocks are not included here, as DIO
5682  * and fallocate do no need to journal data buffers.
5683  */
5684 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5685 {
5686         return ext4_meta_trans_blocks(inode, nrblocks, 1);
5687 }
5688
5689 /*
5690  * The caller must have previously called ext4_reserve_inode_write().
5691  * Give this, we know that the caller already has write access to iloc->bh.
5692  */
5693 int ext4_mark_iloc_dirty(handle_t *handle,
5694                          struct inode *inode, struct ext4_iloc *iloc)
5695 {
5696         int err = 0;
5697
5698         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
5699                 put_bh(iloc->bh);
5700                 return -EIO;
5701         }
5702         ext4_fc_track_inode(inode);
5703
5704         if (IS_I_VERSION(inode))
5705                 inode_inc_iversion(inode);
5706
5707         /* the do_update_inode consumes one bh->b_count */
5708         get_bh(iloc->bh);
5709
5710         /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5711         err = ext4_do_update_inode(handle, inode, iloc);
5712         put_bh(iloc->bh);
5713         return err;
5714 }
5715
5716 /*
5717  * On success, We end up with an outstanding reference count against
5718  * iloc->bh.  This _must_ be cleaned up later.
5719  */
5720
5721 int
5722 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5723                          struct ext4_iloc *iloc)
5724 {
5725         int err;
5726
5727         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5728                 return -EIO;
5729
5730         err = ext4_get_inode_loc(inode, iloc);
5731         if (!err) {
5732                 BUFFER_TRACE(iloc->bh, "get_write_access");
5733                 err = ext4_journal_get_write_access(handle, iloc->bh);
5734                 if (err) {
5735                         brelse(iloc->bh);
5736                         iloc->bh = NULL;
5737                 }
5738         }
5739         ext4_std_error(inode->i_sb, err);
5740         return err;
5741 }
5742
5743 static int __ext4_expand_extra_isize(struct inode *inode,
5744                                      unsigned int new_extra_isize,
5745                                      struct ext4_iloc *iloc,
5746                                      handle_t *handle, int *no_expand)
5747 {
5748         struct ext4_inode *raw_inode;
5749         struct ext4_xattr_ibody_header *header;
5750         unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5751         struct ext4_inode_info *ei = EXT4_I(inode);
5752         int error;
5753
5754         /* this was checked at iget time, but double check for good measure */
5755         if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
5756             (ei->i_extra_isize & 3)) {
5757                 EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
5758                                  ei->i_extra_isize,
5759                                  EXT4_INODE_SIZE(inode->i_sb));
5760                 return -EFSCORRUPTED;
5761         }
5762         if ((new_extra_isize < ei->i_extra_isize) ||
5763             (new_extra_isize < 4) ||
5764             (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
5765                 return -EINVAL; /* Should never happen */
5766
5767         raw_inode = ext4_raw_inode(iloc);
5768
5769         header = IHDR(inode, raw_inode);
5770
5771         /* No extended attributes present */
5772         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5773             header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5774                 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5775                        EXT4_I(inode)->i_extra_isize, 0,
5776                        new_extra_isize - EXT4_I(inode)->i_extra_isize);
5777                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5778                 return 0;
5779         }
5780
5781         /* try to expand with EAs present */
5782         error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5783                                            raw_inode, handle);
5784         if (error) {
5785                 /*
5786                  * Inode size expansion failed; don't try again
5787                  */
5788                 *no_expand = 1;
5789         }
5790
5791         return error;
5792 }
5793
5794 /*
5795  * Expand an inode by new_extra_isize bytes.
5796  * Returns 0 on success or negative error number on failure.
5797  */
5798 static int ext4_try_to_expand_extra_isize(struct inode *inode,
5799                                           unsigned int new_extra_isize,
5800                                           struct ext4_iloc iloc,
5801                                           handle_t *handle)
5802 {
5803         int no_expand;
5804         int error;
5805
5806         if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5807                 return -EOVERFLOW;
5808
5809         /*
5810          * In nojournal mode, we can immediately attempt to expand
5811          * the inode.  When journaled, we first need to obtain extra
5812          * buffer credits since we may write into the EA block
5813          * with this same handle. If journal_extend fails, then it will
5814          * only result in a minor loss of functionality for that inode.
5815          * If this is felt to be critical, then e2fsck should be run to
5816          * force a large enough s_min_extra_isize.
5817          */
5818         if (ext4_journal_extend(handle,
5819                                 EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
5820                 return -ENOSPC;
5821
5822         if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5823                 return -EBUSY;
5824
5825         error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5826                                           handle, &no_expand);
5827         ext4_write_unlock_xattr(inode, &no_expand);
5828
5829         return error;
5830 }
5831
5832 int ext4_expand_extra_isize(struct inode *inode,
5833                             unsigned int new_extra_isize,
5834                             struct ext4_iloc *iloc)
5835 {
5836         handle_t *handle;
5837         int no_expand;
5838         int error, rc;
5839
5840         if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5841                 brelse(iloc->bh);
5842                 return -EOVERFLOW;
5843         }
5844
5845         handle = ext4_journal_start(inode, EXT4_HT_INODE,
5846                                     EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5847         if (IS_ERR(handle)) {
5848                 error = PTR_ERR(handle);
5849                 brelse(iloc->bh);
5850                 return error;
5851         }
5852
5853         ext4_write_lock_xattr(inode, &no_expand);
5854
5855         BUFFER_TRACE(iloc->bh, "get_write_access");
5856         error = ext4_journal_get_write_access(handle, iloc->bh);
5857         if (error) {
5858                 brelse(iloc->bh);
5859                 goto out_unlock;
5860         }
5861
5862         error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5863                                           handle, &no_expand);
5864
5865         rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5866         if (!error)
5867                 error = rc;
5868
5869 out_unlock:
5870         ext4_write_unlock_xattr(inode, &no_expand);
5871         ext4_journal_stop(handle);
5872         return error;
5873 }
5874
5875 /*
5876  * What we do here is to mark the in-core inode as clean with respect to inode
5877  * dirtiness (it may still be data-dirty).
5878  * This means that the in-core inode may be reaped by prune_icache
5879  * without having to perform any I/O.  This is a very good thing,
5880  * because *any* task may call prune_icache - even ones which
5881  * have a transaction open against a different journal.
5882  *
5883  * Is this cheating?  Not really.  Sure, we haven't written the
5884  * inode out, but prune_icache isn't a user-visible syncing function.
5885  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5886  * we start and wait on commits.
5887  */
5888 int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
5889                                 const char *func, unsigned int line)
5890 {
5891         struct ext4_iloc iloc;
5892         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5893         int err;
5894
5895         might_sleep();
5896         trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5897         err = ext4_reserve_inode_write(handle, inode, &iloc);
5898         if (err)
5899                 goto out;
5900
5901         if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5902                 ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5903                                                iloc, handle);
5904
5905         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5906 out:
5907         if (unlikely(err))
5908                 ext4_error_inode_err(inode, func, line, 0, err,
5909                                         "mark_inode_dirty error");
5910         return err;
5911 }
5912
5913 /*
5914  * ext4_dirty_inode() is called from __mark_inode_dirty()
5915  *
5916  * We're really interested in the case where a file is being extended.
5917  * i_size has been changed by generic_commit_write() and we thus need
5918  * to include the updated inode in the current transaction.
5919  *
5920  * Also, dquot_alloc_block() will always dirty the inode when blocks
5921  * are allocated to the file.
5922  *
5923  * If the inode is marked synchronous, we don't honour that here - doing
5924  * so would cause a commit on atime updates, which we don't bother doing.
5925  * We handle synchronous inodes at the highest possible level.
5926  *
5927  * If only the I_DIRTY_TIME flag is set, we can skip everything.  If
5928  * I_DIRTY_TIME and I_DIRTY_SYNC is set, the only inode fields we need
5929  * to copy into the on-disk inode structure are the timestamp files.
5930  */
5931 void ext4_dirty_inode(struct inode *inode, int flags)
5932 {
5933         handle_t *handle;
5934
5935         if (flags == I_DIRTY_TIME)
5936                 return;
5937         handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5938         if (IS_ERR(handle))
5939                 goto out;
5940
5941         ext4_mark_inode_dirty(handle, inode);
5942
5943         ext4_journal_stop(handle);
5944 out:
5945         return;
5946 }
5947
5948 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5949 {
5950         journal_t *journal;
5951         handle_t *handle;
5952         int err;
5953         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5954
5955         /*
5956          * We have to be very careful here: changing a data block's
5957          * journaling status dynamically is dangerous.  If we write a
5958          * data block to the journal, change the status and then delete
5959          * that block, we risk forgetting to revoke the old log record
5960          * from the journal and so a subsequent replay can corrupt data.
5961          * So, first we make sure that the journal is empty and that
5962          * nobody is changing anything.
5963          */
5964
5965         journal = EXT4_JOURNAL(inode);
5966         if (!journal)
5967                 return 0;
5968         if (is_journal_aborted(journal))
5969                 return -EROFS;
5970
5971         /* Wait for all existing dio workers */
5972         inode_dio_wait(inode);
5973
5974         /*
5975          * Before flushing the journal and switching inode's aops, we have
5976          * to flush all dirty data the inode has. There can be outstanding
5977          * delayed allocations, there can be unwritten extents created by
5978          * fallocate or buffered writes in dioread_nolock mode covered by
5979          * dirty data which can be converted only after flushing the dirty
5980          * data (and journalled aops don't know how to handle these cases).
5981          */
5982         if (val) {
5983                 down_write(&EXT4_I(inode)->i_mmap_sem);
5984                 err = filemap_write_and_wait(inode->i_mapping);
5985                 if (err < 0) {
5986                         up_write(&EXT4_I(inode)->i_mmap_sem);
5987                         return err;
5988                 }
5989         }
5990
5991         percpu_down_write(&sbi->s_writepages_rwsem);
5992         jbd2_journal_lock_updates(journal);
5993
5994         /*
5995          * OK, there are no updates running now, and all cached data is
5996          * synced to disk.  We are now in a completely consistent state
5997          * which doesn't have anything in the journal, and we know that
5998          * no filesystem updates are running, so it is safe to modify
5999          * the inode's in-core data-journaling state flag now.
6000          */
6001
6002         if (val)
6003                 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6004         else {
6005                 err = jbd2_journal_flush(journal);
6006                 if (err < 0) {
6007                         jbd2_journal_unlock_updates(journal);
6008                         percpu_up_write(&sbi->s_writepages_rwsem);
6009                         return err;
6010                 }
6011                 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6012         }
6013         ext4_set_aops(inode);
6014
6015         jbd2_journal_unlock_updates(journal);
6016         percpu_up_write(&sbi->s_writepages_rwsem);
6017
6018         if (val)
6019                 up_write(&EXT4_I(inode)->i_mmap_sem);
6020
6021         /* Finally we can mark the inode as dirty. */
6022
6023         handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
6024         if (IS_ERR(handle))
6025                 return PTR_ERR(handle);
6026
6027         ext4_fc_mark_ineligible(inode->i_sb,
6028                 EXT4_FC_REASON_JOURNAL_FLAG_CHANGE);
6029         err = ext4_mark_inode_dirty(handle, inode);
6030         ext4_handle_sync(handle);
6031         ext4_journal_stop(handle);
6032         ext4_std_error(inode->i_sb, err);
6033
6034         return err;
6035 }
6036
6037 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
6038 {
6039         return !buffer_mapped(bh);
6040 }
6041
6042 vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
6043 {
6044         struct vm_area_struct *vma = vmf->vma;
6045         struct page *page = vmf->page;
6046         loff_t size;
6047         unsigned long len;
6048         int err;
6049         vm_fault_t ret;
6050         struct file *file = vma->vm_file;
6051         struct inode *inode = file_inode(file);
6052         struct address_space *mapping = inode->i_mapping;
6053         handle_t *handle;
6054         get_block_t *get_block;
6055         int retries = 0;
6056
6057         if (unlikely(IS_IMMUTABLE(inode)))
6058                 return VM_FAULT_SIGBUS;
6059
6060         sb_start_pagefault(inode->i_sb);
6061         file_update_time(vma->vm_file);
6062
6063         down_read(&EXT4_I(inode)->i_mmap_sem);
6064
6065         err = ext4_convert_inline_data(inode);
6066         if (err)
6067                 goto out_ret;
6068
6069         /*
6070          * On data journalling we skip straight to the transaction handle:
6071          * there's no delalloc; page truncated will be checked later; the
6072          * early return w/ all buffers mapped (calculates size/len) can't
6073          * be used; and there's no dioread_nolock, so only ext4_get_block.
6074          */
6075         if (ext4_should_journal_data(inode))
6076                 goto retry_alloc;
6077
6078         /* Delalloc case is easy... */
6079         if (test_opt(inode->i_sb, DELALLOC) &&
6080             !ext4_nonda_switch(inode->i_sb)) {
6081                 do {
6082                         err = block_page_mkwrite(vma, vmf,
6083                                                    ext4_da_get_block_prep);
6084                 } while (err == -ENOSPC &&
6085                        ext4_should_retry_alloc(inode->i_sb, &retries));
6086                 goto out_ret;
6087         }
6088
6089         lock_page(page);
6090         size = i_size_read(inode);
6091         /* Page got truncated from under us? */
6092         if (page->mapping != mapping || page_offset(page) > size) {
6093                 unlock_page(page);
6094                 ret = VM_FAULT_NOPAGE;
6095                 goto out;
6096         }
6097
6098         if (page->index == size >> PAGE_SHIFT)
6099                 len = size & ~PAGE_MASK;
6100         else
6101                 len = PAGE_SIZE;
6102         /*
6103          * Return if we have all the buffers mapped. This avoids the need to do
6104          * journal_start/journal_stop which can block and take a long time
6105          *
6106          * This cannot be done for data journalling, as we have to add the
6107          * inode to the transaction's list to writeprotect pages on commit.
6108          */
6109         if (page_has_buffers(page)) {
6110                 if (!ext4_walk_page_buffers(NULL, page_buffers(page),
6111                                             0, len, NULL,
6112                                             ext4_bh_unmapped)) {
6113                         /* Wait so that we don't change page under IO */
6114                         wait_for_stable_page(page);
6115                         ret = VM_FAULT_LOCKED;
6116                         goto out;
6117                 }
6118         }
6119         unlock_page(page);
6120         /* OK, we need to fill the hole... */
6121         if (ext4_should_dioread_nolock(inode))
6122                 get_block = ext4_get_block_unwritten;
6123         else
6124                 get_block = ext4_get_block;
6125 retry_alloc:
6126         handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6127                                     ext4_writepage_trans_blocks(inode));
6128         if (IS_ERR(handle)) {
6129                 ret = VM_FAULT_SIGBUS;
6130                 goto out;
6131         }
6132         /*
6133          * Data journalling can't use block_page_mkwrite() because it
6134          * will set_buffer_dirty() before do_journal_get_write_access()
6135          * thus might hit warning messages for dirty metadata buffers.
6136          */
6137         if (!ext4_should_journal_data(inode)) {
6138                 err = block_page_mkwrite(vma, vmf, get_block);
6139         } else {
6140                 lock_page(page);
6141                 size = i_size_read(inode);
6142                 /* Page got truncated from under us? */
6143                 if (page->mapping != mapping || page_offset(page) > size) {
6144                         ret = VM_FAULT_NOPAGE;
6145                         goto out_error;
6146                 }
6147
6148                 if (page->index == size >> PAGE_SHIFT)
6149                         len = size & ~PAGE_MASK;
6150                 else
6151                         len = PAGE_SIZE;
6152
6153                 err = __block_write_begin(page, 0, len, ext4_get_block);
6154                 if (!err) {
6155                         ret = VM_FAULT_SIGBUS;
6156                         if (ext4_walk_page_buffers(handle, page_buffers(page),
6157                                         0, len, NULL, do_journal_get_write_access))
6158                                 goto out_error;
6159                         if (ext4_walk_page_buffers(handle, page_buffers(page),
6160                                         0, len, NULL, write_end_fn))
6161                                 goto out_error;
6162                         if (ext4_jbd2_inode_add_write(handle, inode,
6163                                                       page_offset(page), len))
6164                                 goto out_error;
6165                         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
6166                 } else {
6167                         unlock_page(page);
6168                 }
6169         }
6170         ext4_journal_stop(handle);
6171         if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6172                 goto retry_alloc;
6173 out_ret:
6174         ret = block_page_mkwrite_return(err);
6175 out:
6176         up_read(&EXT4_I(inode)->i_mmap_sem);
6177         sb_end_pagefault(inode->i_sb);
6178         return ret;
6179 out_error:
6180         unlock_page(page);
6181         ext4_journal_stop(handle);
6182         goto out;
6183 }
6184
6185 vm_fault_t ext4_filemap_fault(struct vm_fault *vmf)
6186 {
6187         struct inode *inode = file_inode(vmf->vma->vm_file);
6188         vm_fault_t ret;
6189
6190         down_read(&EXT4_I(inode)->i_mmap_sem);
6191         ret = filemap_fault(vmf);
6192         up_read(&EXT4_I(inode)->i_mmap_sem);
6193
6194         return ret;
6195 }