Merge tag 'spi-fix-v5.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/brooni...
[linux-2.6-microblaze.git] / fs / ext4 / file.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/file.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/file.c
13  *
14  *  Copyright (C) 1991, 1992  Linus Torvalds
15  *
16  *  ext4 fs regular file handling primitives
17  *
18  *  64-bit file support on 64-bit platforms by Jakub Jelinek
19  *      (jj@sunsite.ms.mff.cuni.cz)
20  */
21
22 #include <linux/time.h>
23 #include <linux/fs.h>
24 #include <linux/iomap.h>
25 #include <linux/mount.h>
26 #include <linux/path.h>
27 #include <linux/dax.h>
28 #include <linux/quotaops.h>
29 #include <linux/pagevec.h>
30 #include <linux/uio.h>
31 #include <linux/mman.h>
32 #include <linux/backing-dev.h>
33 #include "ext4.h"
34 #include "ext4_jbd2.h"
35 #include "xattr.h"
36 #include "acl.h"
37 #include "truncate.h"
38
39 static bool ext4_dio_supported(struct inode *inode)
40 {
41         if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode))
42                 return false;
43         if (fsverity_active(inode))
44                 return false;
45         if (ext4_should_journal_data(inode))
46                 return false;
47         if (ext4_has_inline_data(inode))
48                 return false;
49         return true;
50 }
51
52 static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
53 {
54         ssize_t ret;
55         struct inode *inode = file_inode(iocb->ki_filp);
56
57         if (iocb->ki_flags & IOCB_NOWAIT) {
58                 if (!inode_trylock_shared(inode))
59                         return -EAGAIN;
60         } else {
61                 inode_lock_shared(inode);
62         }
63
64         if (!ext4_dio_supported(inode)) {
65                 inode_unlock_shared(inode);
66                 /*
67                  * Fallback to buffered I/O if the operation being performed on
68                  * the inode is not supported by direct I/O. The IOCB_DIRECT
69                  * flag needs to be cleared here in order to ensure that the
70                  * direct I/O path within generic_file_read_iter() is not
71                  * taken.
72                  */
73                 iocb->ki_flags &= ~IOCB_DIRECT;
74                 return generic_file_read_iter(iocb, to);
75         }
76
77         ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0);
78         inode_unlock_shared(inode);
79
80         file_accessed(iocb->ki_filp);
81         return ret;
82 }
83
84 #ifdef CONFIG_FS_DAX
85 static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
86 {
87         struct inode *inode = file_inode(iocb->ki_filp);
88         ssize_t ret;
89
90         if (iocb->ki_flags & IOCB_NOWAIT) {
91                 if (!inode_trylock_shared(inode))
92                         return -EAGAIN;
93         } else {
94                 inode_lock_shared(inode);
95         }
96         /*
97          * Recheck under inode lock - at this point we are sure it cannot
98          * change anymore
99          */
100         if (!IS_DAX(inode)) {
101                 inode_unlock_shared(inode);
102                 /* Fallback to buffered IO in case we cannot support DAX */
103                 return generic_file_read_iter(iocb, to);
104         }
105         ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
106         inode_unlock_shared(inode);
107
108         file_accessed(iocb->ki_filp);
109         return ret;
110 }
111 #endif
112
113 static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
114 {
115         struct inode *inode = file_inode(iocb->ki_filp);
116
117         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
118                 return -EIO;
119
120         if (!iov_iter_count(to))
121                 return 0; /* skip atime */
122
123 #ifdef CONFIG_FS_DAX
124         if (IS_DAX(inode))
125                 return ext4_dax_read_iter(iocb, to);
126 #endif
127         if (iocb->ki_flags & IOCB_DIRECT)
128                 return ext4_dio_read_iter(iocb, to);
129
130         return generic_file_read_iter(iocb, to);
131 }
132
133 /*
134  * Called when an inode is released. Note that this is different
135  * from ext4_file_open: open gets called at every open, but release
136  * gets called only when /all/ the files are closed.
137  */
138 static int ext4_release_file(struct inode *inode, struct file *filp)
139 {
140         if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
141                 ext4_alloc_da_blocks(inode);
142                 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
143         }
144         /* if we are the last writer on the inode, drop the block reservation */
145         if ((filp->f_mode & FMODE_WRITE) &&
146                         (atomic_read(&inode->i_writecount) == 1) &&
147                         !EXT4_I(inode)->i_reserved_data_blocks) {
148                 down_write(&EXT4_I(inode)->i_data_sem);
149                 ext4_discard_preallocations(inode, 0);
150                 up_write(&EXT4_I(inode)->i_data_sem);
151         }
152         if (is_dx(inode) && filp->private_data)
153                 ext4_htree_free_dir_info(filp->private_data);
154
155         return 0;
156 }
157
158 /*
159  * This tests whether the IO in question is block-aligned or not.
160  * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
161  * are converted to written only after the IO is complete.  Until they are
162  * mapped, these blocks appear as holes, so dio_zero_block() will assume that
163  * it needs to zero out portions of the start and/or end block.  If 2 AIO
164  * threads are at work on the same unwritten block, they must be synchronized
165  * or one thread will zero the other's data, causing corruption.
166  */
167 static bool
168 ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
169 {
170         struct super_block *sb = inode->i_sb;
171         unsigned long blockmask = sb->s_blocksize - 1;
172
173         if ((pos | iov_iter_alignment(from)) & blockmask)
174                 return true;
175
176         return false;
177 }
178
179 static bool
180 ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
181 {
182         if (offset + len > i_size_read(inode) ||
183             offset + len > EXT4_I(inode)->i_disksize)
184                 return true;
185         return false;
186 }
187
188 /* Is IO overwriting allocated and initialized blocks? */
189 static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
190 {
191         struct ext4_map_blocks map;
192         unsigned int blkbits = inode->i_blkbits;
193         int err, blklen;
194
195         if (pos + len > i_size_read(inode))
196                 return false;
197
198         map.m_lblk = pos >> blkbits;
199         map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
200         blklen = map.m_len;
201
202         err = ext4_map_blocks(NULL, inode, &map, 0);
203         /*
204          * 'err==len' means that all of the blocks have been preallocated,
205          * regardless of whether they have been initialized or not. To exclude
206          * unwritten extents, we need to check m_flags.
207          */
208         return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
209 }
210
211 static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
212                                          struct iov_iter *from)
213 {
214         struct inode *inode = file_inode(iocb->ki_filp);
215         ssize_t ret;
216
217         if (unlikely(IS_IMMUTABLE(inode)))
218                 return -EPERM;
219
220         ret = generic_write_checks(iocb, from);
221         if (ret <= 0)
222                 return ret;
223
224         /*
225          * If we have encountered a bitmap-format file, the size limit
226          * is smaller than s_maxbytes, which is for extent-mapped files.
227          */
228         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
229                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
230
231                 if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
232                         return -EFBIG;
233                 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
234         }
235
236         return iov_iter_count(from);
237 }
238
239 static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
240 {
241         ssize_t ret, count;
242
243         count = ext4_generic_write_checks(iocb, from);
244         if (count <= 0)
245                 return count;
246
247         ret = file_modified(iocb->ki_filp);
248         if (ret)
249                 return ret;
250         return count;
251 }
252
253 static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
254                                         struct iov_iter *from)
255 {
256         ssize_t ret;
257         struct inode *inode = file_inode(iocb->ki_filp);
258
259         if (iocb->ki_flags & IOCB_NOWAIT)
260                 return -EOPNOTSUPP;
261
262         ext4_fc_start_update(inode);
263         inode_lock(inode);
264         ret = ext4_write_checks(iocb, from);
265         if (ret <= 0)
266                 goto out;
267
268         current->backing_dev_info = inode_to_bdi(inode);
269         ret = generic_perform_write(iocb->ki_filp, from, iocb->ki_pos);
270         current->backing_dev_info = NULL;
271
272 out:
273         inode_unlock(inode);
274         ext4_fc_stop_update(inode);
275         if (likely(ret > 0)) {
276                 iocb->ki_pos += ret;
277                 ret = generic_write_sync(iocb, ret);
278         }
279
280         return ret;
281 }
282
283 static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
284                                            ssize_t written, size_t count)
285 {
286         handle_t *handle;
287         bool truncate = false;
288         u8 blkbits = inode->i_blkbits;
289         ext4_lblk_t written_blk, end_blk;
290         int ret;
291
292         /*
293          * Note that EXT4_I(inode)->i_disksize can get extended up to
294          * inode->i_size while the I/O was running due to writeback of delalloc
295          * blocks. But, the code in ext4_iomap_alloc() is careful to use
296          * zeroed/unwritten extents if this is possible; thus we won't leave
297          * uninitialized blocks in a file even if we didn't succeed in writing
298          * as much as we intended.
299          */
300         WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
301         if (offset + count <= EXT4_I(inode)->i_disksize) {
302                 /*
303                  * We need to ensure that the inode is removed from the orphan
304                  * list if it has been added prematurely, due to writeback of
305                  * delalloc blocks.
306                  */
307                 if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
308                         handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
309
310                         if (IS_ERR(handle)) {
311                                 ext4_orphan_del(NULL, inode);
312                                 return PTR_ERR(handle);
313                         }
314
315                         ext4_orphan_del(handle, inode);
316                         ext4_journal_stop(handle);
317                 }
318
319                 return written;
320         }
321
322         if (written < 0)
323                 goto truncate;
324
325         handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
326         if (IS_ERR(handle)) {
327                 written = PTR_ERR(handle);
328                 goto truncate;
329         }
330
331         if (ext4_update_inode_size(inode, offset + written)) {
332                 ret = ext4_mark_inode_dirty(handle, inode);
333                 if (unlikely(ret)) {
334                         written = ret;
335                         ext4_journal_stop(handle);
336                         goto truncate;
337                 }
338         }
339
340         /*
341          * We may need to truncate allocated but not written blocks beyond EOF.
342          */
343         written_blk = ALIGN(offset + written, 1 << blkbits);
344         end_blk = ALIGN(offset + count, 1 << blkbits);
345         if (written_blk < end_blk && ext4_can_truncate(inode))
346                 truncate = true;
347
348         /*
349          * Remove the inode from the orphan list if it has been extended and
350          * everything went OK.
351          */
352         if (!truncate && inode->i_nlink)
353                 ext4_orphan_del(handle, inode);
354         ext4_journal_stop(handle);
355
356         if (truncate) {
357 truncate:
358                 ext4_truncate_failed_write(inode);
359                 /*
360                  * If the truncate operation failed early, then the inode may
361                  * still be on the orphan list. In that case, we need to try
362                  * remove the inode from the in-memory linked list.
363                  */
364                 if (inode->i_nlink)
365                         ext4_orphan_del(NULL, inode);
366         }
367
368         return written;
369 }
370
371 static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
372                                  int error, unsigned int flags)
373 {
374         loff_t pos = iocb->ki_pos;
375         struct inode *inode = file_inode(iocb->ki_filp);
376
377         if (error)
378                 return error;
379
380         if (size && flags & IOMAP_DIO_UNWRITTEN) {
381                 error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
382                 if (error < 0)
383                         return error;
384         }
385         /*
386          * If we are extending the file, we have to update i_size here before
387          * page cache gets invalidated in iomap_dio_rw(). Otherwise racing
388          * buffered reads could zero out too much from page cache pages. Update
389          * of on-disk size will happen later in ext4_dio_write_iter() where
390          * we have enough information to also perform orphan list handling etc.
391          * Note that we perform all extending writes synchronously under
392          * i_rwsem held exclusively so i_size update is safe here in that case.
393          * If the write was not extending, we cannot see pos > i_size here
394          * because operations reducing i_size like truncate wait for all
395          * outstanding DIO before updating i_size.
396          */
397         pos += size;
398         if (pos > i_size_read(inode))
399                 i_size_write(inode, pos);
400
401         return 0;
402 }
403
404 static const struct iomap_dio_ops ext4_dio_write_ops = {
405         .end_io = ext4_dio_write_end_io,
406 };
407
408 /*
409  * The intention here is to start with shared lock acquired then see if any
410  * condition requires an exclusive inode lock. If yes, then we restart the
411  * whole operation by releasing the shared lock and acquiring exclusive lock.
412  *
413  * - For unaligned_io we never take shared lock as it may cause data corruption
414  *   when two unaligned IO tries to modify the same block e.g. while zeroing.
415  *
416  * - For extending writes case we don't take the shared lock, since it requires
417  *   updating inode i_disksize and/or orphan handling with exclusive lock.
418  *
419  * - shared locking will only be true mostly with overwrites. Otherwise we will
420  *   switch to exclusive i_rwsem lock.
421  */
422 static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
423                                      bool *ilock_shared, bool *extend)
424 {
425         struct file *file = iocb->ki_filp;
426         struct inode *inode = file_inode(file);
427         loff_t offset;
428         size_t count;
429         ssize_t ret;
430
431 restart:
432         ret = ext4_generic_write_checks(iocb, from);
433         if (ret <= 0)
434                 goto out;
435
436         offset = iocb->ki_pos;
437         count = ret;
438         if (ext4_extending_io(inode, offset, count))
439                 *extend = true;
440         /*
441          * Determine whether the IO operation will overwrite allocated
442          * and initialized blocks.
443          * We need exclusive i_rwsem for changing security info
444          * in file_modified().
445          */
446         if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
447              !ext4_overwrite_io(inode, offset, count))) {
448                 if (iocb->ki_flags & IOCB_NOWAIT) {
449                         ret = -EAGAIN;
450                         goto out;
451                 }
452                 inode_unlock_shared(inode);
453                 *ilock_shared = false;
454                 inode_lock(inode);
455                 goto restart;
456         }
457
458         ret = file_modified(file);
459         if (ret < 0)
460                 goto out;
461
462         return count;
463 out:
464         if (*ilock_shared)
465                 inode_unlock_shared(inode);
466         else
467                 inode_unlock(inode);
468         return ret;
469 }
470
471 static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
472 {
473         ssize_t ret;
474         handle_t *handle;
475         struct inode *inode = file_inode(iocb->ki_filp);
476         loff_t offset = iocb->ki_pos;
477         size_t count = iov_iter_count(from);
478         const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
479         bool extend = false, unaligned_io = false;
480         bool ilock_shared = true;
481
482         /*
483          * We initially start with shared inode lock unless it is
484          * unaligned IO which needs exclusive lock anyways.
485          */
486         if (ext4_unaligned_io(inode, from, offset)) {
487                 unaligned_io = true;
488                 ilock_shared = false;
489         }
490         /*
491          * Quick check here without any i_rwsem lock to see if it is extending
492          * IO. A more reliable check is done in ext4_dio_write_checks() with
493          * proper locking in place.
494          */
495         if (offset + count > i_size_read(inode))
496                 ilock_shared = false;
497
498         if (iocb->ki_flags & IOCB_NOWAIT) {
499                 if (ilock_shared) {
500                         if (!inode_trylock_shared(inode))
501                                 return -EAGAIN;
502                 } else {
503                         if (!inode_trylock(inode))
504                                 return -EAGAIN;
505                 }
506         } else {
507                 if (ilock_shared)
508                         inode_lock_shared(inode);
509                 else
510                         inode_lock(inode);
511         }
512
513         /* Fallback to buffered I/O if the inode does not support direct I/O. */
514         if (!ext4_dio_supported(inode)) {
515                 if (ilock_shared)
516                         inode_unlock_shared(inode);
517                 else
518                         inode_unlock(inode);
519                 return ext4_buffered_write_iter(iocb, from);
520         }
521
522         ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
523         if (ret <= 0)
524                 return ret;
525
526         /* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
527         if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
528                 ret = -EAGAIN;
529                 goto out;
530         }
531
532         offset = iocb->ki_pos;
533         count = ret;
534
535         /*
536          * Unaligned direct IO must be serialized among each other as zeroing
537          * of partial blocks of two competing unaligned IOs can result in data
538          * corruption.
539          *
540          * So we make sure we don't allow any unaligned IO in flight.
541          * For IOs where we need not wait (like unaligned non-AIO DIO),
542          * below inode_dio_wait() may anyway become a no-op, since we start
543          * with exclusive lock.
544          */
545         if (unaligned_io)
546                 inode_dio_wait(inode);
547
548         if (extend) {
549                 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
550                 if (IS_ERR(handle)) {
551                         ret = PTR_ERR(handle);
552                         goto out;
553                 }
554
555                 ext4_fc_start_update(inode);
556                 ret = ext4_orphan_add(handle, inode);
557                 ext4_fc_stop_update(inode);
558                 if (ret) {
559                         ext4_journal_stop(handle);
560                         goto out;
561                 }
562
563                 ext4_journal_stop(handle);
564         }
565
566         if (ilock_shared)
567                 iomap_ops = &ext4_iomap_overwrite_ops;
568         ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
569                            (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0);
570         if (ret == -ENOTBLK)
571                 ret = 0;
572
573         if (extend)
574                 ret = ext4_handle_inode_extension(inode, offset, ret, count);
575
576 out:
577         if (ilock_shared)
578                 inode_unlock_shared(inode);
579         else
580                 inode_unlock(inode);
581
582         if (ret >= 0 && iov_iter_count(from)) {
583                 ssize_t err;
584                 loff_t endbyte;
585
586                 offset = iocb->ki_pos;
587                 err = ext4_buffered_write_iter(iocb, from);
588                 if (err < 0)
589                         return err;
590
591                 /*
592                  * We need to ensure that the pages within the page cache for
593                  * the range covered by this I/O are written to disk and
594                  * invalidated. This is in attempt to preserve the expected
595                  * direct I/O semantics in the case we fallback to buffered I/O
596                  * to complete off the I/O request.
597                  */
598                 ret += err;
599                 endbyte = offset + err - 1;
600                 err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
601                                                    offset, endbyte);
602                 if (!err)
603                         invalidate_mapping_pages(iocb->ki_filp->f_mapping,
604                                                  offset >> PAGE_SHIFT,
605                                                  endbyte >> PAGE_SHIFT);
606         }
607
608         return ret;
609 }
610
611 #ifdef CONFIG_FS_DAX
612 static ssize_t
613 ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
614 {
615         ssize_t ret;
616         size_t count;
617         loff_t offset;
618         handle_t *handle;
619         bool extend = false;
620         struct inode *inode = file_inode(iocb->ki_filp);
621
622         if (iocb->ki_flags & IOCB_NOWAIT) {
623                 if (!inode_trylock(inode))
624                         return -EAGAIN;
625         } else {
626                 inode_lock(inode);
627         }
628
629         ret = ext4_write_checks(iocb, from);
630         if (ret <= 0)
631                 goto out;
632
633         offset = iocb->ki_pos;
634         count = iov_iter_count(from);
635
636         if (offset + count > EXT4_I(inode)->i_disksize) {
637                 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
638                 if (IS_ERR(handle)) {
639                         ret = PTR_ERR(handle);
640                         goto out;
641                 }
642
643                 ret = ext4_orphan_add(handle, inode);
644                 if (ret) {
645                         ext4_journal_stop(handle);
646                         goto out;
647                 }
648
649                 extend = true;
650                 ext4_journal_stop(handle);
651         }
652
653         ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
654
655         if (extend)
656                 ret = ext4_handle_inode_extension(inode, offset, ret, count);
657 out:
658         inode_unlock(inode);
659         if (ret > 0)
660                 ret = generic_write_sync(iocb, ret);
661         return ret;
662 }
663 #endif
664
665 static ssize_t
666 ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
667 {
668         struct inode *inode = file_inode(iocb->ki_filp);
669
670         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
671                 return -EIO;
672
673 #ifdef CONFIG_FS_DAX
674         if (IS_DAX(inode))
675                 return ext4_dax_write_iter(iocb, from);
676 #endif
677         if (iocb->ki_flags & IOCB_DIRECT)
678                 return ext4_dio_write_iter(iocb, from);
679         else
680                 return ext4_buffered_write_iter(iocb, from);
681 }
682
683 #ifdef CONFIG_FS_DAX
684 static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
685                 enum page_entry_size pe_size)
686 {
687         int error = 0;
688         vm_fault_t result;
689         int retries = 0;
690         handle_t *handle = NULL;
691         struct inode *inode = file_inode(vmf->vma->vm_file);
692         struct super_block *sb = inode->i_sb;
693
694         /*
695          * We have to distinguish real writes from writes which will result in a
696          * COW page; COW writes should *not* poke the journal (the file will not
697          * be changed). Doing so would cause unintended failures when mounted
698          * read-only.
699          *
700          * We check for VM_SHARED rather than vmf->cow_page since the latter is
701          * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
702          * other sizes, dax_iomap_fault will handle splitting / fallback so that
703          * we eventually come back with a COW page.
704          */
705         bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
706                 (vmf->vma->vm_flags & VM_SHARED);
707         struct address_space *mapping = vmf->vma->vm_file->f_mapping;
708         pfn_t pfn;
709
710         if (write) {
711                 sb_start_pagefault(sb);
712                 file_update_time(vmf->vma->vm_file);
713                 filemap_invalidate_lock_shared(mapping);
714 retry:
715                 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
716                                                EXT4_DATA_TRANS_BLOCKS(sb));
717                 if (IS_ERR(handle)) {
718                         filemap_invalidate_unlock_shared(mapping);
719                         sb_end_pagefault(sb);
720                         return VM_FAULT_SIGBUS;
721                 }
722         } else {
723                 filemap_invalidate_lock_shared(mapping);
724         }
725         result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
726         if (write) {
727                 ext4_journal_stop(handle);
728
729                 if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
730                     ext4_should_retry_alloc(sb, &retries))
731                         goto retry;
732                 /* Handling synchronous page fault? */
733                 if (result & VM_FAULT_NEEDDSYNC)
734                         result = dax_finish_sync_fault(vmf, pe_size, pfn);
735                 filemap_invalidate_unlock_shared(mapping);
736                 sb_end_pagefault(sb);
737         } else {
738                 filemap_invalidate_unlock_shared(mapping);
739         }
740
741         return result;
742 }
743
744 static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
745 {
746         return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
747 }
748
749 static const struct vm_operations_struct ext4_dax_vm_ops = {
750         .fault          = ext4_dax_fault,
751         .huge_fault     = ext4_dax_huge_fault,
752         .page_mkwrite   = ext4_dax_fault,
753         .pfn_mkwrite    = ext4_dax_fault,
754 };
755 #else
756 #define ext4_dax_vm_ops ext4_file_vm_ops
757 #endif
758
759 static const struct vm_operations_struct ext4_file_vm_ops = {
760         .fault          = filemap_fault,
761         .map_pages      = filemap_map_pages,
762         .page_mkwrite   = ext4_page_mkwrite,
763 };
764
765 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
766 {
767         struct inode *inode = file->f_mapping->host;
768         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
769         struct dax_device *dax_dev = sbi->s_daxdev;
770
771         if (unlikely(ext4_forced_shutdown(sbi)))
772                 return -EIO;
773
774         /*
775          * We don't support synchronous mappings for non-DAX files and
776          * for DAX files if underneath dax_device is not synchronous.
777          */
778         if (!daxdev_mapping_supported(vma, dax_dev))
779                 return -EOPNOTSUPP;
780
781         file_accessed(file);
782         if (IS_DAX(file_inode(file))) {
783                 vma->vm_ops = &ext4_dax_vm_ops;
784                 vma->vm_flags |= VM_HUGEPAGE;
785         } else {
786                 vma->vm_ops = &ext4_file_vm_ops;
787         }
788         return 0;
789 }
790
791 static int ext4_sample_last_mounted(struct super_block *sb,
792                                     struct vfsmount *mnt)
793 {
794         struct ext4_sb_info *sbi = EXT4_SB(sb);
795         struct path path;
796         char buf[64], *cp;
797         handle_t *handle;
798         int err;
799
800         if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
801                 return 0;
802
803         if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
804                 return 0;
805
806         ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
807         /*
808          * Sample where the filesystem has been mounted and
809          * store it in the superblock for sysadmin convenience
810          * when trying to sort through large numbers of block
811          * devices or filesystem images.
812          */
813         memset(buf, 0, sizeof(buf));
814         path.mnt = mnt;
815         path.dentry = mnt->mnt_root;
816         cp = d_path(&path, buf, sizeof(buf));
817         err = 0;
818         if (IS_ERR(cp))
819                 goto out;
820
821         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
822         err = PTR_ERR(handle);
823         if (IS_ERR(handle))
824                 goto out;
825         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
826         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
827                                             EXT4_JTR_NONE);
828         if (err)
829                 goto out_journal;
830         lock_buffer(sbi->s_sbh);
831         strncpy(sbi->s_es->s_last_mounted, cp,
832                 sizeof(sbi->s_es->s_last_mounted));
833         ext4_superblock_csum_set(sb);
834         unlock_buffer(sbi->s_sbh);
835         ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
836 out_journal:
837         ext4_journal_stop(handle);
838 out:
839         sb_end_intwrite(sb);
840         return err;
841 }
842
843 static int ext4_file_open(struct inode *inode, struct file *filp)
844 {
845         int ret;
846
847         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
848                 return -EIO;
849
850         ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
851         if (ret)
852                 return ret;
853
854         ret = fscrypt_file_open(inode, filp);
855         if (ret)
856                 return ret;
857
858         ret = fsverity_file_open(inode, filp);
859         if (ret)
860                 return ret;
861
862         /*
863          * Set up the jbd2_inode if we are opening the inode for
864          * writing and the journal is present
865          */
866         if (filp->f_mode & FMODE_WRITE) {
867                 ret = ext4_inode_attach_jinode(inode);
868                 if (ret < 0)
869                         return ret;
870         }
871
872         filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
873         return dquot_file_open(inode, filp);
874 }
875
876 /*
877  * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
878  * by calling generic_file_llseek_size() with the appropriate maxbytes
879  * value for each.
880  */
881 loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
882 {
883         struct inode *inode = file->f_mapping->host;
884         loff_t maxbytes;
885
886         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
887                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
888         else
889                 maxbytes = inode->i_sb->s_maxbytes;
890
891         switch (whence) {
892         default:
893                 return generic_file_llseek_size(file, offset, whence,
894                                                 maxbytes, i_size_read(inode));
895         case SEEK_HOLE:
896                 inode_lock_shared(inode);
897                 offset = iomap_seek_hole(inode, offset,
898                                          &ext4_iomap_report_ops);
899                 inode_unlock_shared(inode);
900                 break;
901         case SEEK_DATA:
902                 inode_lock_shared(inode);
903                 offset = iomap_seek_data(inode, offset,
904                                          &ext4_iomap_report_ops);
905                 inode_unlock_shared(inode);
906                 break;
907         }
908
909         if (offset < 0)
910                 return offset;
911         return vfs_setpos(file, offset, maxbytes);
912 }
913
914 const struct file_operations ext4_file_operations = {
915         .llseek         = ext4_llseek,
916         .read_iter      = ext4_file_read_iter,
917         .write_iter     = ext4_file_write_iter,
918         .iopoll         = iomap_dio_iopoll,
919         .unlocked_ioctl = ext4_ioctl,
920 #ifdef CONFIG_COMPAT
921         .compat_ioctl   = ext4_compat_ioctl,
922 #endif
923         .mmap           = ext4_file_mmap,
924         .mmap_supported_flags = MAP_SYNC,
925         .open           = ext4_file_open,
926         .release        = ext4_release_file,
927         .fsync          = ext4_sync_file,
928         .get_unmapped_area = thp_get_unmapped_area,
929         .splice_read    = generic_file_splice_read,
930         .splice_write   = iter_file_splice_write,
931         .fallocate      = ext4_fallocate,
932 };
933
934 const struct inode_operations ext4_file_inode_operations = {
935         .setattr        = ext4_setattr,
936         .getattr        = ext4_file_getattr,
937         .listxattr      = ext4_listxattr,
938         .get_acl        = ext4_get_acl,
939         .set_acl        = ext4_set_acl,
940         .fiemap         = ext4_fiemap,
941         .fileattr_get   = ext4_fileattr_get,
942         .fileattr_set   = ext4_fileattr_set,
943 };
944