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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/*
40 * Returns %true if the given DIO request should be attempted with DIO, or
41 * %false if it should fall back to buffered I/O.
42 *
43 * DIO isn't well specified; when it's unsupported (either due to the request
44 * being misaligned, or due to the file not supporting DIO at all), filesystems
45 * either fall back to buffered I/O or return EINVAL. For files that don't use
46 * any special features like encryption or verity, ext4 has traditionally
47 * returned EINVAL for misaligned DIO. iomap_dio_rw() uses this convention too.
48 * In this case, we should attempt the DIO, *not* fall back to buffered I/O.
49 *
50 * In contrast, in cases where DIO is unsupported due to ext4 features, ext4
51 * traditionally falls back to buffered I/O.
52 *
53 * This function implements the traditional ext4 behavior in all these cases.
54 */
55static bool ext4_should_use_dio(struct kiocb *iocb, struct iov_iter *iter)
56{
57 struct inode *inode = file_inode(iocb->ki_filp);
58 u32 dio_align = ext4_dio_alignment(inode);
59
60 if (dio_align == 0)
61 return false;
62
63 if (dio_align == 1)
64 return true;
65
66 return IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter), dio_align);
67}
68
69static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
70{
71 ssize_t ret;
72 struct inode *inode = file_inode(iocb->ki_filp);
73
74 if (iocb->ki_flags & IOCB_NOWAIT) {
75 if (!inode_trylock_shared(inode))
76 return -EAGAIN;
77 } else {
78 inode_lock_shared(inode);
79 }
80
81 if (!ext4_should_use_dio(iocb, to)) {
82 inode_unlock_shared(inode);
83 /*
84 * Fallback to buffered I/O if the operation being performed on
85 * the inode is not supported by direct I/O. The IOCB_DIRECT
86 * flag needs to be cleared here in order to ensure that the
87 * direct I/O path within generic_file_read_iter() is not
88 * taken.
89 */
90 iocb->ki_flags &= ~IOCB_DIRECT;
91 return generic_file_read_iter(iocb, to);
92 }
93
94 ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, NULL, 0);
95 inode_unlock_shared(inode);
96
97 file_accessed(iocb->ki_filp);
98 return ret;
99}
100
101#ifdef CONFIG_FS_DAX
102static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
103{
104 struct inode *inode = file_inode(iocb->ki_filp);
105 ssize_t ret;
106
107 if (iocb->ki_flags & IOCB_NOWAIT) {
108 if (!inode_trylock_shared(inode))
109 return -EAGAIN;
110 } else {
111 inode_lock_shared(inode);
112 }
113 /*
114 * Recheck under inode lock - at this point we are sure it cannot
115 * change anymore
116 */
117 if (!IS_DAX(inode)) {
118 inode_unlock_shared(inode);
119 /* Fallback to buffered IO in case we cannot support DAX */
120 return generic_file_read_iter(iocb, to);
121 }
122 ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
123 inode_unlock_shared(inode);
124
125 file_accessed(iocb->ki_filp);
126 return ret;
127}
128#endif
129
130static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
131{
132 struct inode *inode = file_inode(iocb->ki_filp);
133
134 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
135 return -EIO;
136
137 if (!iov_iter_count(to))
138 return 0; /* skip atime */
139
140#ifdef CONFIG_FS_DAX
141 if (IS_DAX(inode))
142 return ext4_dax_read_iter(iocb, to);
143#endif
144 if (iocb->ki_flags & IOCB_DIRECT)
145 return ext4_dio_read_iter(iocb, to);
146
147 return generic_file_read_iter(iocb, to);
148}
149
150/*
151 * Called when an inode is released. Note that this is different
152 * from ext4_file_open: open gets called at every open, but release
153 * gets called only when /all/ the files are closed.
154 */
155static int ext4_release_file(struct inode *inode, struct file *filp)
156{
157 if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
158 ext4_alloc_da_blocks(inode);
159 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
160 }
161 /* if we are the last writer on the inode, drop the block reservation */
162 if ((filp->f_mode & FMODE_WRITE) &&
163 (atomic_read(&inode->i_writecount) == 1) &&
164 !EXT4_I(inode)->i_reserved_data_blocks) {
165 down_write(&EXT4_I(inode)->i_data_sem);
166 ext4_discard_preallocations(inode, 0);
167 up_write(&EXT4_I(inode)->i_data_sem);
168 }
169 if (is_dx(inode) && filp->private_data)
170 ext4_htree_free_dir_info(filp->private_data);
171
172 return 0;
173}
174
175/*
176 * This tests whether the IO in question is block-aligned or not.
177 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
178 * are converted to written only after the IO is complete. Until they are
179 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
180 * it needs to zero out portions of the start and/or end block. If 2 AIO
181 * threads are at work on the same unwritten block, they must be synchronized
182 * or one thread will zero the other's data, causing corruption.
183 */
184static bool
185ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
186{
187 struct super_block *sb = inode->i_sb;
188 unsigned long blockmask = sb->s_blocksize - 1;
189
190 if ((pos | iov_iter_alignment(from)) & blockmask)
191 return true;
192
193 return false;
194}
195
196static bool
197ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
198{
199 if (offset + len > i_size_read(inode) ||
200 offset + len > EXT4_I(inode)->i_disksize)
201 return true;
202 return false;
203}
204
205/* Is IO overwriting allocated and initialized blocks? */
206static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
207{
208 struct ext4_map_blocks map;
209 unsigned int blkbits = inode->i_blkbits;
210 int err, blklen;
211
212 if (pos + len > i_size_read(inode))
213 return false;
214
215 map.m_lblk = pos >> blkbits;
216 map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
217 blklen = map.m_len;
218
219 err = ext4_map_blocks(NULL, inode, &map, 0);
220 /*
221 * 'err==len' means that all of the blocks have been preallocated,
222 * regardless of whether they have been initialized or not. To exclude
223 * unwritten extents, we need to check m_flags.
224 */
225 return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
226}
227
228static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
229 struct iov_iter *from)
230{
231 struct inode *inode = file_inode(iocb->ki_filp);
232 ssize_t ret;
233
234 if (unlikely(IS_IMMUTABLE(inode)))
235 return -EPERM;
236
237 ret = generic_write_checks(iocb, from);
238 if (ret <= 0)
239 return ret;
240
241 /*
242 * If we have encountered a bitmap-format file, the size limit
243 * is smaller than s_maxbytes, which is for extent-mapped files.
244 */
245 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
246 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
247
248 if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
249 return -EFBIG;
250 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
251 }
252
253 return iov_iter_count(from);
254}
255
256static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
257{
258 ssize_t ret, count;
259
260 count = ext4_generic_write_checks(iocb, from);
261 if (count <= 0)
262 return count;
263
264 ret = file_modified(iocb->ki_filp);
265 if (ret)
266 return ret;
267 return count;
268}
269
270static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
271 struct iov_iter *from)
272{
273 ssize_t ret;
274 struct inode *inode = file_inode(iocb->ki_filp);
275
276 if (iocb->ki_flags & IOCB_NOWAIT)
277 return -EOPNOTSUPP;
278
279 inode_lock(inode);
280 ret = ext4_write_checks(iocb, from);
281 if (ret <= 0)
282 goto out;
283
284 current->backing_dev_info = inode_to_bdi(inode);
285 ret = generic_perform_write(iocb, from);
286 current->backing_dev_info = NULL;
287
288out:
289 inode_unlock(inode);
290 if (likely(ret > 0)) {
291 iocb->ki_pos += ret;
292 ret = generic_write_sync(iocb, ret);
293 }
294
295 return ret;
296}
297
298static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
299 ssize_t written, size_t count)
300{
301 handle_t *handle;
302 bool truncate = false;
303 u8 blkbits = inode->i_blkbits;
304 ext4_lblk_t written_blk, end_blk;
305 int ret;
306
307 /*
308 * Note that EXT4_I(inode)->i_disksize can get extended up to
309 * inode->i_size while the I/O was running due to writeback of delalloc
310 * blocks. But, the code in ext4_iomap_alloc() is careful to use
311 * zeroed/unwritten extents if this is possible; thus we won't leave
312 * uninitialized blocks in a file even if we didn't succeed in writing
313 * as much as we intended.
314 */
315 WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
316 if (offset + count <= EXT4_I(inode)->i_disksize) {
317 /*
318 * We need to ensure that the inode is removed from the orphan
319 * list if it has been added prematurely, due to writeback of
320 * delalloc blocks.
321 */
322 if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
323 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
324
325 if (IS_ERR(handle)) {
326 ext4_orphan_del(NULL, inode);
327 return PTR_ERR(handle);
328 }
329
330 ext4_orphan_del(handle, inode);
331 ext4_journal_stop(handle);
332 }
333
334 return written;
335 }
336
337 if (written < 0)
338 goto truncate;
339
340 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
341 if (IS_ERR(handle)) {
342 written = PTR_ERR(handle);
343 goto truncate;
344 }
345
346 if (ext4_update_inode_size(inode, offset + written)) {
347 ret = ext4_mark_inode_dirty(handle, inode);
348 if (unlikely(ret)) {
349 written = ret;
350 ext4_journal_stop(handle);
351 goto truncate;
352 }
353 }
354
355 /*
356 * We may need to truncate allocated but not written blocks beyond EOF.
357 */
358 written_blk = ALIGN(offset + written, 1 << blkbits);
359 end_blk = ALIGN(offset + count, 1 << blkbits);
360 if (written_blk < end_blk && ext4_can_truncate(inode))
361 truncate = true;
362
363 /*
364 * Remove the inode from the orphan list if it has been extended and
365 * everything went OK.
366 */
367 if (!truncate && inode->i_nlink)
368 ext4_orphan_del(handle, inode);
369 ext4_journal_stop(handle);
370
371 if (truncate) {
372truncate:
373 ext4_truncate_failed_write(inode);
374 /*
375 * If the truncate operation failed early, then the inode may
376 * still be on the orphan list. In that case, we need to try
377 * remove the inode from the in-memory linked list.
378 */
379 if (inode->i_nlink)
380 ext4_orphan_del(NULL, inode);
381 }
382
383 return written;
384}
385
386static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
387 int error, unsigned int flags)
388{
389 loff_t pos = iocb->ki_pos;
390 struct inode *inode = file_inode(iocb->ki_filp);
391
392 if (error)
393 return error;
394
395 if (size && flags & IOMAP_DIO_UNWRITTEN) {
396 error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
397 if (error < 0)
398 return error;
399 }
400 /*
401 * If we are extending the file, we have to update i_size here before
402 * page cache gets invalidated in iomap_dio_rw(). Otherwise racing
403 * buffered reads could zero out too much from page cache pages. Update
404 * of on-disk size will happen later in ext4_dio_write_iter() where
405 * we have enough information to also perform orphan list handling etc.
406 * Note that we perform all extending writes synchronously under
407 * i_rwsem held exclusively so i_size update is safe here in that case.
408 * If the write was not extending, we cannot see pos > i_size here
409 * because operations reducing i_size like truncate wait for all
410 * outstanding DIO before updating i_size.
411 */
412 pos += size;
413 if (pos > i_size_read(inode))
414 i_size_write(inode, pos);
415
416 return 0;
417}
418
419static const struct iomap_dio_ops ext4_dio_write_ops = {
420 .end_io = ext4_dio_write_end_io,
421};
422
423/*
424 * The intention here is to start with shared lock acquired then see if any
425 * condition requires an exclusive inode lock. If yes, then we restart the
426 * whole operation by releasing the shared lock and acquiring exclusive lock.
427 *
428 * - For unaligned_io we never take shared lock as it may cause data corruption
429 * when two unaligned IO tries to modify the same block e.g. while zeroing.
430 *
431 * - For extending writes case we don't take the shared lock, since it requires
432 * updating inode i_disksize and/or orphan handling with exclusive lock.
433 *
434 * - shared locking will only be true mostly with overwrites. Otherwise we will
435 * switch to exclusive i_rwsem lock.
436 */
437static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
438 bool *ilock_shared, bool *extend)
439{
440 struct file *file = iocb->ki_filp;
441 struct inode *inode = file_inode(file);
442 loff_t offset;
443 size_t count;
444 ssize_t ret;
445
446restart:
447 ret = ext4_generic_write_checks(iocb, from);
448 if (ret <= 0)
449 goto out;
450
451 offset = iocb->ki_pos;
452 count = ret;
453 if (ext4_extending_io(inode, offset, count))
454 *extend = true;
455 /*
456 * Determine whether the IO operation will overwrite allocated
457 * and initialized blocks.
458 * We need exclusive i_rwsem for changing security info
459 * in file_modified().
460 */
461 if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
462 !ext4_overwrite_io(inode, offset, count))) {
463 if (iocb->ki_flags & IOCB_NOWAIT) {
464 ret = -EAGAIN;
465 goto out;
466 }
467 inode_unlock_shared(inode);
468 *ilock_shared = false;
469 inode_lock(inode);
470 goto restart;
471 }
472
473 ret = file_modified(file);
474 if (ret < 0)
475 goto out;
476
477 return count;
478out:
479 if (*ilock_shared)
480 inode_unlock_shared(inode);
481 else
482 inode_unlock(inode);
483 return ret;
484}
485
486static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
487{
488 ssize_t ret;
489 handle_t *handle;
490 struct inode *inode = file_inode(iocb->ki_filp);
491 loff_t offset = iocb->ki_pos;
492 size_t count = iov_iter_count(from);
493 const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
494 bool extend = false, unaligned_io = false;
495 bool ilock_shared = true;
496
497 /*
498 * We initially start with shared inode lock unless it is
499 * unaligned IO which needs exclusive lock anyways.
500 */
501 if (ext4_unaligned_io(inode, from, offset)) {
502 unaligned_io = true;
503 ilock_shared = false;
504 }
505 /*
506 * Quick check here without any i_rwsem lock to see if it is extending
507 * IO. A more reliable check is done in ext4_dio_write_checks() with
508 * proper locking in place.
509 */
510 if (offset + count > i_size_read(inode))
511 ilock_shared = false;
512
513 if (iocb->ki_flags & IOCB_NOWAIT) {
514 if (ilock_shared) {
515 if (!inode_trylock_shared(inode))
516 return -EAGAIN;
517 } else {
518 if (!inode_trylock(inode))
519 return -EAGAIN;
520 }
521 } else {
522 if (ilock_shared)
523 inode_lock_shared(inode);
524 else
525 inode_lock(inode);
526 }
527
528 /* Fallback to buffered I/O if the inode does not support direct I/O. */
529 if (!ext4_should_use_dio(iocb, from)) {
530 if (ilock_shared)
531 inode_unlock_shared(inode);
532 else
533 inode_unlock(inode);
534 return ext4_buffered_write_iter(iocb, from);
535 }
536
537 ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
538 if (ret <= 0)
539 return ret;
540
541 /* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
542 if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
543 ret = -EAGAIN;
544 goto out;
545 }
546 /*
547 * Make sure inline data cannot be created anymore since we are going
548 * to allocate blocks for DIO. We know the inode does not have any
549 * inline data now because ext4_dio_supported() checked for that.
550 */
551 ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
552
553 offset = iocb->ki_pos;
554 count = ret;
555
556 /*
557 * Unaligned direct IO must be serialized among each other as zeroing
558 * of partial blocks of two competing unaligned IOs can result in data
559 * corruption.
560 *
561 * So we make sure we don't allow any unaligned IO in flight.
562 * For IOs where we need not wait (like unaligned non-AIO DIO),
563 * below inode_dio_wait() may anyway become a no-op, since we start
564 * with exclusive lock.
565 */
566 if (unaligned_io)
567 inode_dio_wait(inode);
568
569 if (extend) {
570 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
571 if (IS_ERR(handle)) {
572 ret = PTR_ERR(handle);
573 goto out;
574 }
575
576 ret = ext4_orphan_add(handle, inode);
577 if (ret) {
578 ext4_journal_stop(handle);
579 goto out;
580 }
581
582 ext4_journal_stop(handle);
583 }
584
585 if (ilock_shared)
586 iomap_ops = &ext4_iomap_overwrite_ops;
587 ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
588 (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0,
589 NULL, 0);
590 if (ret == -ENOTBLK)
591 ret = 0;
592
593 if (extend)
594 ret = ext4_handle_inode_extension(inode, offset, ret, count);
595
596out:
597 if (ilock_shared)
598 inode_unlock_shared(inode);
599 else
600 inode_unlock(inode);
601
602 if (ret >= 0 && iov_iter_count(from)) {
603 ssize_t err;
604 loff_t endbyte;
605
606 offset = iocb->ki_pos;
607 err = ext4_buffered_write_iter(iocb, from);
608 if (err < 0)
609 return err;
610
611 /*
612 * We need to ensure that the pages within the page cache for
613 * the range covered by this I/O are written to disk and
614 * invalidated. This is in attempt to preserve the expected
615 * direct I/O semantics in the case we fallback to buffered I/O
616 * to complete off the I/O request.
617 */
618 ret += err;
619 endbyte = offset + err - 1;
620 err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
621 offset, endbyte);
622 if (!err)
623 invalidate_mapping_pages(iocb->ki_filp->f_mapping,
624 offset >> PAGE_SHIFT,
625 endbyte >> PAGE_SHIFT);
626 }
627
628 return ret;
629}
630
631#ifdef CONFIG_FS_DAX
632static ssize_t
633ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
634{
635 ssize_t ret;
636 size_t count;
637 loff_t offset;
638 handle_t *handle;
639 bool extend = false;
640 struct inode *inode = file_inode(iocb->ki_filp);
641
642 if (iocb->ki_flags & IOCB_NOWAIT) {
643 if (!inode_trylock(inode))
644 return -EAGAIN;
645 } else {
646 inode_lock(inode);
647 }
648
649 ret = ext4_write_checks(iocb, from);
650 if (ret <= 0)
651 goto out;
652
653 offset = iocb->ki_pos;
654 count = iov_iter_count(from);
655
656 if (offset + count > EXT4_I(inode)->i_disksize) {
657 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
658 if (IS_ERR(handle)) {
659 ret = PTR_ERR(handle);
660 goto out;
661 }
662
663 ret = ext4_orphan_add(handle, inode);
664 if (ret) {
665 ext4_journal_stop(handle);
666 goto out;
667 }
668
669 extend = true;
670 ext4_journal_stop(handle);
671 }
672
673 ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
674
675 if (extend)
676 ret = ext4_handle_inode_extension(inode, offset, ret, count);
677out:
678 inode_unlock(inode);
679 if (ret > 0)
680 ret = generic_write_sync(iocb, ret);
681 return ret;
682}
683#endif
684
685static ssize_t
686ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
687{
688 struct inode *inode = file_inode(iocb->ki_filp);
689
690 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
691 return -EIO;
692
693#ifdef CONFIG_FS_DAX
694 if (IS_DAX(inode))
695 return ext4_dax_write_iter(iocb, from);
696#endif
697 if (iocb->ki_flags & IOCB_DIRECT)
698 return ext4_dio_write_iter(iocb, from);
699 else
700 return ext4_buffered_write_iter(iocb, from);
701}
702
703#ifdef CONFIG_FS_DAX
704static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
705 enum page_entry_size pe_size)
706{
707 int error = 0;
708 vm_fault_t result;
709 int retries = 0;
710 handle_t *handle = NULL;
711 struct inode *inode = file_inode(vmf->vma->vm_file);
712 struct super_block *sb = inode->i_sb;
713
714 /*
715 * We have to distinguish real writes from writes which will result in a
716 * COW page; COW writes should *not* poke the journal (the file will not
717 * be changed). Doing so would cause unintended failures when mounted
718 * read-only.
719 *
720 * We check for VM_SHARED rather than vmf->cow_page since the latter is
721 * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
722 * other sizes, dax_iomap_fault will handle splitting / fallback so that
723 * we eventually come back with a COW page.
724 */
725 bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
726 (vmf->vma->vm_flags & VM_SHARED);
727 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
728 pfn_t pfn;
729
730 if (write) {
731 sb_start_pagefault(sb);
732 file_update_time(vmf->vma->vm_file);
733 filemap_invalidate_lock_shared(mapping);
734retry:
735 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
736 EXT4_DATA_TRANS_BLOCKS(sb));
737 if (IS_ERR(handle)) {
738 filemap_invalidate_unlock_shared(mapping);
739 sb_end_pagefault(sb);
740 return VM_FAULT_SIGBUS;
741 }
742 } else {
743 filemap_invalidate_lock_shared(mapping);
744 }
745 result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
746 if (write) {
747 ext4_journal_stop(handle);
748
749 if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
750 ext4_should_retry_alloc(sb, &retries))
751 goto retry;
752 /* Handling synchronous page fault? */
753 if (result & VM_FAULT_NEEDDSYNC)
754 result = dax_finish_sync_fault(vmf, pe_size, pfn);
755 filemap_invalidate_unlock_shared(mapping);
756 sb_end_pagefault(sb);
757 } else {
758 filemap_invalidate_unlock_shared(mapping);
759 }
760
761 return result;
762}
763
764static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
765{
766 return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
767}
768
769static const struct vm_operations_struct ext4_dax_vm_ops = {
770 .fault = ext4_dax_fault,
771 .huge_fault = ext4_dax_huge_fault,
772 .page_mkwrite = ext4_dax_fault,
773 .pfn_mkwrite = ext4_dax_fault,
774};
775#else
776#define ext4_dax_vm_ops ext4_file_vm_ops
777#endif
778
779static const struct vm_operations_struct ext4_file_vm_ops = {
780 .fault = filemap_fault,
781 .map_pages = filemap_map_pages,
782 .page_mkwrite = ext4_page_mkwrite,
783};
784
785static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
786{
787 struct inode *inode = file->f_mapping->host;
788 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
789 struct dax_device *dax_dev = sbi->s_daxdev;
790
791 if (unlikely(ext4_forced_shutdown(sbi)))
792 return -EIO;
793
794 /*
795 * We don't support synchronous mappings for non-DAX files and
796 * for DAX files if underneath dax_device is not synchronous.
797 */
798 if (!daxdev_mapping_supported(vma, dax_dev))
799 return -EOPNOTSUPP;
800
801 file_accessed(file);
802 if (IS_DAX(file_inode(file))) {
803 vma->vm_ops = &ext4_dax_vm_ops;
804 vma->vm_flags |= VM_HUGEPAGE;
805 } else {
806 vma->vm_ops = &ext4_file_vm_ops;
807 }
808 return 0;
809}
810
811static int ext4_sample_last_mounted(struct super_block *sb,
812 struct vfsmount *mnt)
813{
814 struct ext4_sb_info *sbi = EXT4_SB(sb);
815 struct path path;
816 char buf[64], *cp;
817 handle_t *handle;
818 int err;
819
820 if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
821 return 0;
822
823 if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
824 return 0;
825
826 ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
827 /*
828 * Sample where the filesystem has been mounted and
829 * store it in the superblock for sysadmin convenience
830 * when trying to sort through large numbers of block
831 * devices or filesystem images.
832 */
833 memset(buf, 0, sizeof(buf));
834 path.mnt = mnt;
835 path.dentry = mnt->mnt_root;
836 cp = d_path(&path, buf, sizeof(buf));
837 err = 0;
838 if (IS_ERR(cp))
839 goto out;
840
841 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
842 err = PTR_ERR(handle);
843 if (IS_ERR(handle))
844 goto out;
845 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
846 err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
847 EXT4_JTR_NONE);
848 if (err)
849 goto out_journal;
850 lock_buffer(sbi->s_sbh);
851 strncpy(sbi->s_es->s_last_mounted, cp,
852 sizeof(sbi->s_es->s_last_mounted));
853 ext4_superblock_csum_set(sb);
854 unlock_buffer(sbi->s_sbh);
855 ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
856out_journal:
857 ext4_journal_stop(handle);
858out:
859 sb_end_intwrite(sb);
860 return err;
861}
862
863static int ext4_file_open(struct inode *inode, struct file *filp)
864{
865 int ret;
866
867 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
868 return -EIO;
869
870 ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
871 if (ret)
872 return ret;
873
874 ret = fscrypt_file_open(inode, filp);
875 if (ret)
876 return ret;
877
878 ret = fsverity_file_open(inode, filp);
879 if (ret)
880 return ret;
881
882 /*
883 * Set up the jbd2_inode if we are opening the inode for
884 * writing and the journal is present
885 */
886 if (filp->f_mode & FMODE_WRITE) {
887 ret = ext4_inode_attach_jinode(inode);
888 if (ret < 0)
889 return ret;
890 }
891
892 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
893 return dquot_file_open(inode, filp);
894}
895
896/*
897 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
898 * by calling generic_file_llseek_size() with the appropriate maxbytes
899 * value for each.
900 */
901loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
902{
903 struct inode *inode = file->f_mapping->host;
904 loff_t maxbytes;
905
906 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
907 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
908 else
909 maxbytes = inode->i_sb->s_maxbytes;
910
911 switch (whence) {
912 default:
913 return generic_file_llseek_size(file, offset, whence,
914 maxbytes, i_size_read(inode));
915 case SEEK_HOLE:
916 inode_lock_shared(inode);
917 offset = iomap_seek_hole(inode, offset,
918 &ext4_iomap_report_ops);
919 inode_unlock_shared(inode);
920 break;
921 case SEEK_DATA:
922 inode_lock_shared(inode);
923 offset = iomap_seek_data(inode, offset,
924 &ext4_iomap_report_ops);
925 inode_unlock_shared(inode);
926 break;
927 }
928
929 if (offset < 0)
930 return offset;
931 return vfs_setpos(file, offset, maxbytes);
932}
933
934const struct file_operations ext4_file_operations = {
935 .llseek = ext4_llseek,
936 .read_iter = ext4_file_read_iter,
937 .write_iter = ext4_file_write_iter,
938 .iopoll = iocb_bio_iopoll,
939 .unlocked_ioctl = ext4_ioctl,
940#ifdef CONFIG_COMPAT
941 .compat_ioctl = ext4_compat_ioctl,
942#endif
943 .mmap = ext4_file_mmap,
944 .mmap_supported_flags = MAP_SYNC,
945 .open = ext4_file_open,
946 .release = ext4_release_file,
947 .fsync = ext4_sync_file,
948 .get_unmapped_area = thp_get_unmapped_area,
949 .splice_read = generic_file_splice_read,
950 .splice_write = iter_file_splice_write,
951 .fallocate = ext4_fallocate,
952};
953
954const struct inode_operations ext4_file_inode_operations = {
955 .setattr = ext4_setattr,
956 .getattr = ext4_file_getattr,
957 .listxattr = ext4_listxattr,
958 .get_inode_acl = ext4_get_acl,
959 .set_acl = ext4_set_acl,
960 .fiemap = ext4_fiemap,
961 .fileattr_get = ext4_fileattr_get,
962 .fileattr_set = ext4_fileattr_set,
963};
964
1/*
2 * linux/fs/ext4/file.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/file.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext4 fs regular file handling primitives
16 *
17 * 64-bit file support on 64-bit platforms by Jakub Jelinek
18 * (jj@sunsite.ms.mff.cuni.cz)
19 */
20
21#include <linux/time.h>
22#include <linux/fs.h>
23#include <linux/jbd2.h>
24#include <linux/mount.h>
25#include <linux/path.h>
26#include <linux/aio.h>
27#include <linux/quotaops.h>
28#include <linux/pagevec.h>
29#include "ext4.h"
30#include "ext4_jbd2.h"
31#include "xattr.h"
32#include "acl.h"
33
34/*
35 * Called when an inode is released. Note that this is different
36 * from ext4_file_open: open gets called at every open, but release
37 * gets called only when /all/ the files are closed.
38 */
39static int ext4_release_file(struct inode *inode, struct file *filp)
40{
41 if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
42 ext4_alloc_da_blocks(inode);
43 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
44 }
45 /* if we are the last writer on the inode, drop the block reservation */
46 if ((filp->f_mode & FMODE_WRITE) &&
47 (atomic_read(&inode->i_writecount) == 1) &&
48 !EXT4_I(inode)->i_reserved_data_blocks)
49 {
50 down_write(&EXT4_I(inode)->i_data_sem);
51 ext4_discard_preallocations(inode);
52 up_write(&EXT4_I(inode)->i_data_sem);
53 }
54 if (is_dx(inode) && filp->private_data)
55 ext4_htree_free_dir_info(filp->private_data);
56
57 return 0;
58}
59
60void ext4_unwritten_wait(struct inode *inode)
61{
62 wait_queue_head_t *wq = ext4_ioend_wq(inode);
63
64 wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
65}
66
67/*
68 * This tests whether the IO in question is block-aligned or not.
69 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
70 * are converted to written only after the IO is complete. Until they are
71 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
72 * it needs to zero out portions of the start and/or end block. If 2 AIO
73 * threads are at work on the same unwritten block, they must be synchronized
74 * or one thread will zero the other's data, causing corruption.
75 */
76static int
77ext4_unaligned_aio(struct inode *inode, const struct iovec *iov,
78 unsigned long nr_segs, loff_t pos)
79{
80 struct super_block *sb = inode->i_sb;
81 int blockmask = sb->s_blocksize - 1;
82 size_t count = iov_length(iov, nr_segs);
83 loff_t final_size = pos + count;
84
85 if (pos >= i_size_read(inode))
86 return 0;
87
88 if ((pos & blockmask) || (final_size & blockmask))
89 return 1;
90
91 return 0;
92}
93
94static ssize_t
95ext4_file_dio_write(struct kiocb *iocb, const struct iovec *iov,
96 unsigned long nr_segs, loff_t pos)
97{
98 struct file *file = iocb->ki_filp;
99 struct inode *inode = file->f_mapping->host;
100 struct blk_plug plug;
101 int unaligned_aio = 0;
102 ssize_t ret;
103 int overwrite = 0;
104 size_t length = iov_length(iov, nr_segs);
105
106 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
107 !is_sync_kiocb(iocb))
108 unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);
109
110 /* Unaligned direct AIO must be serialized; see comment above */
111 if (unaligned_aio) {
112 mutex_lock(ext4_aio_mutex(inode));
113 ext4_unwritten_wait(inode);
114 }
115
116 BUG_ON(iocb->ki_pos != pos);
117
118 mutex_lock(&inode->i_mutex);
119 blk_start_plug(&plug);
120
121 iocb->private = &overwrite;
122
123 /* check whether we do a DIO overwrite or not */
124 if (ext4_should_dioread_nolock(inode) && !unaligned_aio &&
125 !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
126 struct ext4_map_blocks map;
127 unsigned int blkbits = inode->i_blkbits;
128 int err, len;
129
130 map.m_lblk = pos >> blkbits;
131 map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
132 - map.m_lblk;
133 len = map.m_len;
134
135 err = ext4_map_blocks(NULL, inode, &map, 0);
136 /*
137 * 'err==len' means that all of blocks has been preallocated no
138 * matter they are initialized or not. For excluding
139 * uninitialized extents, we need to check m_flags. There are
140 * two conditions that indicate for initialized extents.
141 * 1) If we hit extent cache, EXT4_MAP_MAPPED flag is returned;
142 * 2) If we do a real lookup, non-flags are returned.
143 * So we should check these two conditions.
144 */
145 if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
146 overwrite = 1;
147 }
148
149 ret = __generic_file_aio_write(iocb, iov, nr_segs);
150 mutex_unlock(&inode->i_mutex);
151
152 if (ret > 0) {
153 ssize_t err;
154
155 err = generic_write_sync(file, iocb->ki_pos - ret, ret);
156 if (err < 0)
157 ret = err;
158 }
159 blk_finish_plug(&plug);
160
161 if (unaligned_aio)
162 mutex_unlock(ext4_aio_mutex(inode));
163
164 return ret;
165}
166
167static ssize_t
168ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
169 unsigned long nr_segs, loff_t pos)
170{
171 struct inode *inode = file_inode(iocb->ki_filp);
172 ssize_t ret;
173
174 /*
175 * If we have encountered a bitmap-format file, the size limit
176 * is smaller than s_maxbytes, which is for extent-mapped files.
177 */
178
179 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
180 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
181 size_t length = iov_length(iov, nr_segs);
182
183 if ((pos > sbi->s_bitmap_maxbytes ||
184 (pos == sbi->s_bitmap_maxbytes && length > 0)))
185 return -EFBIG;
186
187 if (pos + length > sbi->s_bitmap_maxbytes) {
188 nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
189 sbi->s_bitmap_maxbytes - pos);
190 }
191 }
192
193 if (unlikely(iocb->ki_filp->f_flags & O_DIRECT))
194 ret = ext4_file_dio_write(iocb, iov, nr_segs, pos);
195 else
196 ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
197
198 return ret;
199}
200
201static const struct vm_operations_struct ext4_file_vm_ops = {
202 .fault = filemap_fault,
203 .map_pages = filemap_map_pages,
204 .page_mkwrite = ext4_page_mkwrite,
205 .remap_pages = generic_file_remap_pages,
206};
207
208static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
209{
210 struct address_space *mapping = file->f_mapping;
211
212 if (!mapping->a_ops->readpage)
213 return -ENOEXEC;
214 file_accessed(file);
215 vma->vm_ops = &ext4_file_vm_ops;
216 return 0;
217}
218
219static int ext4_file_open(struct inode * inode, struct file * filp)
220{
221 struct super_block *sb = inode->i_sb;
222 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
223 struct vfsmount *mnt = filp->f_path.mnt;
224 struct path path;
225 char buf[64], *cp;
226
227 if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
228 !(sb->s_flags & MS_RDONLY))) {
229 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
230 /*
231 * Sample where the filesystem has been mounted and
232 * store it in the superblock for sysadmin convenience
233 * when trying to sort through large numbers of block
234 * devices or filesystem images.
235 */
236 memset(buf, 0, sizeof(buf));
237 path.mnt = mnt;
238 path.dentry = mnt->mnt_root;
239 cp = d_path(&path, buf, sizeof(buf));
240 if (!IS_ERR(cp)) {
241 handle_t *handle;
242 int err;
243
244 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
245 if (IS_ERR(handle))
246 return PTR_ERR(handle);
247 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
248 if (err) {
249 ext4_journal_stop(handle);
250 return err;
251 }
252 strlcpy(sbi->s_es->s_last_mounted, cp,
253 sizeof(sbi->s_es->s_last_mounted));
254 ext4_handle_dirty_super(handle, sb);
255 ext4_journal_stop(handle);
256 }
257 }
258 /*
259 * Set up the jbd2_inode if we are opening the inode for
260 * writing and the journal is present
261 */
262 if (filp->f_mode & FMODE_WRITE) {
263 int ret = ext4_inode_attach_jinode(inode);
264 if (ret < 0)
265 return ret;
266 }
267 return dquot_file_open(inode, filp);
268}
269
270/*
271 * Here we use ext4_map_blocks() to get a block mapping for a extent-based
272 * file rather than ext4_ext_walk_space() because we can introduce
273 * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
274 * function. When extent status tree has been fully implemented, it will
275 * track all extent status for a file and we can directly use it to
276 * retrieve the offset for SEEK_DATA/SEEK_HOLE.
277 */
278
279/*
280 * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
281 * lookup page cache to check whether or not there has some data between
282 * [startoff, endoff] because, if this range contains an unwritten extent,
283 * we determine this extent as a data or a hole according to whether the
284 * page cache has data or not.
285 */
286static int ext4_find_unwritten_pgoff(struct inode *inode,
287 int whence,
288 struct ext4_map_blocks *map,
289 loff_t *offset)
290{
291 struct pagevec pvec;
292 unsigned int blkbits;
293 pgoff_t index;
294 pgoff_t end;
295 loff_t endoff;
296 loff_t startoff;
297 loff_t lastoff;
298 int found = 0;
299
300 blkbits = inode->i_sb->s_blocksize_bits;
301 startoff = *offset;
302 lastoff = startoff;
303 endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits;
304
305 index = startoff >> PAGE_CACHE_SHIFT;
306 end = endoff >> PAGE_CACHE_SHIFT;
307
308 pagevec_init(&pvec, 0);
309 do {
310 int i, num;
311 unsigned long nr_pages;
312
313 num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
314 nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
315 (pgoff_t)num);
316 if (nr_pages == 0) {
317 if (whence == SEEK_DATA)
318 break;
319
320 BUG_ON(whence != SEEK_HOLE);
321 /*
322 * If this is the first time to go into the loop and
323 * offset is not beyond the end offset, it will be a
324 * hole at this offset
325 */
326 if (lastoff == startoff || lastoff < endoff)
327 found = 1;
328 break;
329 }
330
331 /*
332 * If this is the first time to go into the loop and
333 * offset is smaller than the first page offset, it will be a
334 * hole at this offset.
335 */
336 if (lastoff == startoff && whence == SEEK_HOLE &&
337 lastoff < page_offset(pvec.pages[0])) {
338 found = 1;
339 break;
340 }
341
342 for (i = 0; i < nr_pages; i++) {
343 struct page *page = pvec.pages[i];
344 struct buffer_head *bh, *head;
345
346 /*
347 * If the current offset is not beyond the end of given
348 * range, it will be a hole.
349 */
350 if (lastoff < endoff && whence == SEEK_HOLE &&
351 page->index > end) {
352 found = 1;
353 *offset = lastoff;
354 goto out;
355 }
356
357 lock_page(page);
358
359 if (unlikely(page->mapping != inode->i_mapping)) {
360 unlock_page(page);
361 continue;
362 }
363
364 if (!page_has_buffers(page)) {
365 unlock_page(page);
366 continue;
367 }
368
369 if (page_has_buffers(page)) {
370 lastoff = page_offset(page);
371 bh = head = page_buffers(page);
372 do {
373 if (buffer_uptodate(bh) ||
374 buffer_unwritten(bh)) {
375 if (whence == SEEK_DATA)
376 found = 1;
377 } else {
378 if (whence == SEEK_HOLE)
379 found = 1;
380 }
381 if (found) {
382 *offset = max_t(loff_t,
383 startoff, lastoff);
384 unlock_page(page);
385 goto out;
386 }
387 lastoff += bh->b_size;
388 bh = bh->b_this_page;
389 } while (bh != head);
390 }
391
392 lastoff = page_offset(page) + PAGE_SIZE;
393 unlock_page(page);
394 }
395
396 /*
397 * The no. of pages is less than our desired, that would be a
398 * hole in there.
399 */
400 if (nr_pages < num && whence == SEEK_HOLE) {
401 found = 1;
402 *offset = lastoff;
403 break;
404 }
405
406 index = pvec.pages[i - 1]->index + 1;
407 pagevec_release(&pvec);
408 } while (index <= end);
409
410out:
411 pagevec_release(&pvec);
412 return found;
413}
414
415/*
416 * ext4_seek_data() retrieves the offset for SEEK_DATA.
417 */
418static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
419{
420 struct inode *inode = file->f_mapping->host;
421 struct ext4_map_blocks map;
422 struct extent_status es;
423 ext4_lblk_t start, last, end;
424 loff_t dataoff, isize;
425 int blkbits;
426 int ret = 0;
427
428 mutex_lock(&inode->i_mutex);
429
430 isize = i_size_read(inode);
431 if (offset >= isize) {
432 mutex_unlock(&inode->i_mutex);
433 return -ENXIO;
434 }
435
436 blkbits = inode->i_sb->s_blocksize_bits;
437 start = offset >> blkbits;
438 last = start;
439 end = isize >> blkbits;
440 dataoff = offset;
441
442 do {
443 map.m_lblk = last;
444 map.m_len = end - last + 1;
445 ret = ext4_map_blocks(NULL, inode, &map, 0);
446 if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
447 if (last != start)
448 dataoff = (loff_t)last << blkbits;
449 break;
450 }
451
452 /*
453 * If there is a delay extent at this offset,
454 * it will be as a data.
455 */
456 ext4_es_find_delayed_extent_range(inode, last, last, &es);
457 if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
458 if (last != start)
459 dataoff = (loff_t)last << blkbits;
460 break;
461 }
462
463 /*
464 * If there is a unwritten extent at this offset,
465 * it will be as a data or a hole according to page
466 * cache that has data or not.
467 */
468 if (map.m_flags & EXT4_MAP_UNWRITTEN) {
469 int unwritten;
470 unwritten = ext4_find_unwritten_pgoff(inode, SEEK_DATA,
471 &map, &dataoff);
472 if (unwritten)
473 break;
474 }
475
476 last++;
477 dataoff = (loff_t)last << blkbits;
478 } while (last <= end);
479
480 mutex_unlock(&inode->i_mutex);
481
482 if (dataoff > isize)
483 return -ENXIO;
484
485 return vfs_setpos(file, dataoff, maxsize);
486}
487
488/*
489 * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
490 */
491static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
492{
493 struct inode *inode = file->f_mapping->host;
494 struct ext4_map_blocks map;
495 struct extent_status es;
496 ext4_lblk_t start, last, end;
497 loff_t holeoff, isize;
498 int blkbits;
499 int ret = 0;
500
501 mutex_lock(&inode->i_mutex);
502
503 isize = i_size_read(inode);
504 if (offset >= isize) {
505 mutex_unlock(&inode->i_mutex);
506 return -ENXIO;
507 }
508
509 blkbits = inode->i_sb->s_blocksize_bits;
510 start = offset >> blkbits;
511 last = start;
512 end = isize >> blkbits;
513 holeoff = offset;
514
515 do {
516 map.m_lblk = last;
517 map.m_len = end - last + 1;
518 ret = ext4_map_blocks(NULL, inode, &map, 0);
519 if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
520 last += ret;
521 holeoff = (loff_t)last << blkbits;
522 continue;
523 }
524
525 /*
526 * If there is a delay extent at this offset,
527 * we will skip this extent.
528 */
529 ext4_es_find_delayed_extent_range(inode, last, last, &es);
530 if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
531 last = es.es_lblk + es.es_len;
532 holeoff = (loff_t)last << blkbits;
533 continue;
534 }
535
536 /*
537 * If there is a unwritten extent at this offset,
538 * it will be as a data or a hole according to page
539 * cache that has data or not.
540 */
541 if (map.m_flags & EXT4_MAP_UNWRITTEN) {
542 int unwritten;
543 unwritten = ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
544 &map, &holeoff);
545 if (!unwritten) {
546 last += ret;
547 holeoff = (loff_t)last << blkbits;
548 continue;
549 }
550 }
551
552 /* find a hole */
553 break;
554 } while (last <= end);
555
556 mutex_unlock(&inode->i_mutex);
557
558 if (holeoff > isize)
559 holeoff = isize;
560
561 return vfs_setpos(file, holeoff, maxsize);
562}
563
564/*
565 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
566 * by calling generic_file_llseek_size() with the appropriate maxbytes
567 * value for each.
568 */
569loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
570{
571 struct inode *inode = file->f_mapping->host;
572 loff_t maxbytes;
573
574 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
575 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
576 else
577 maxbytes = inode->i_sb->s_maxbytes;
578
579 switch (whence) {
580 case SEEK_SET:
581 case SEEK_CUR:
582 case SEEK_END:
583 return generic_file_llseek_size(file, offset, whence,
584 maxbytes, i_size_read(inode));
585 case SEEK_DATA:
586 return ext4_seek_data(file, offset, maxbytes);
587 case SEEK_HOLE:
588 return ext4_seek_hole(file, offset, maxbytes);
589 }
590
591 return -EINVAL;
592}
593
594const struct file_operations ext4_file_operations = {
595 .llseek = ext4_llseek,
596 .read = do_sync_read,
597 .write = do_sync_write,
598 .aio_read = generic_file_aio_read,
599 .aio_write = ext4_file_write,
600 .unlocked_ioctl = ext4_ioctl,
601#ifdef CONFIG_COMPAT
602 .compat_ioctl = ext4_compat_ioctl,
603#endif
604 .mmap = ext4_file_mmap,
605 .open = ext4_file_open,
606 .release = ext4_release_file,
607 .fsync = ext4_sync_file,
608 .splice_read = generic_file_splice_read,
609 .splice_write = generic_file_splice_write,
610 .fallocate = ext4_fallocate,
611};
612
613const struct inode_operations ext4_file_inode_operations = {
614 .setattr = ext4_setattr,
615 .getattr = ext4_getattr,
616 .setxattr = generic_setxattr,
617 .getxattr = generic_getxattr,
618 .listxattr = ext4_listxattr,
619 .removexattr = generic_removexattr,
620 .get_acl = ext4_get_acl,
621 .set_acl = ext4_set_acl,
622 .fiemap = ext4_fiemap,
623};
624