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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/mount.h>
24#include <linux/path.h>
25#include <linux/dax.h>
26#include <linux/quotaops.h>
27#include <linux/pagevec.h>
28#include <linux/uio.h>
29#include "ext4.h"
30#include "ext4_jbd2.h"
31#include "xattr.h"
32#include "acl.h"
33
34#ifdef CONFIG_FS_DAX
35static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
36{
37 struct inode *inode = file_inode(iocb->ki_filp);
38 ssize_t ret;
39
40 inode_lock_shared(inode);
41 /*
42 * Recheck under inode lock - at this point we are sure it cannot
43 * change anymore
44 */
45 if (!IS_DAX(inode)) {
46 inode_unlock_shared(inode);
47 /* Fallback to buffered IO in case we cannot support DAX */
48 return generic_file_read_iter(iocb, to);
49 }
50 ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
51 inode_unlock_shared(inode);
52
53 file_accessed(iocb->ki_filp);
54 return ret;
55}
56#endif
57
58static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
59{
60 if (!iov_iter_count(to))
61 return 0; /* skip atime */
62
63#ifdef CONFIG_FS_DAX
64 if (IS_DAX(file_inode(iocb->ki_filp)))
65 return ext4_dax_read_iter(iocb, to);
66#endif
67 return generic_file_read_iter(iocb, to);
68}
69
70/*
71 * Called when an inode is released. Note that this is different
72 * from ext4_file_open: open gets called at every open, but release
73 * gets called only when /all/ the files are closed.
74 */
75static int ext4_release_file(struct inode *inode, struct file *filp)
76{
77 if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
78 ext4_alloc_da_blocks(inode);
79 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
80 }
81 /* if we are the last writer on the inode, drop the block reservation */
82 if ((filp->f_mode & FMODE_WRITE) &&
83 (atomic_read(&inode->i_writecount) == 1) &&
84 !EXT4_I(inode)->i_reserved_data_blocks)
85 {
86 down_write(&EXT4_I(inode)->i_data_sem);
87 ext4_discard_preallocations(inode);
88 up_write(&EXT4_I(inode)->i_data_sem);
89 }
90 if (is_dx(inode) && filp->private_data)
91 ext4_htree_free_dir_info(filp->private_data);
92
93 return 0;
94}
95
96static void ext4_unwritten_wait(struct inode *inode)
97{
98 wait_queue_head_t *wq = ext4_ioend_wq(inode);
99
100 wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
101}
102
103/*
104 * This tests whether the IO in question is block-aligned or not.
105 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
106 * are converted to written only after the IO is complete. Until they are
107 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
108 * it needs to zero out portions of the start and/or end block. If 2 AIO
109 * threads are at work on the same unwritten block, they must be synchronized
110 * or one thread will zero the other's data, causing corruption.
111 */
112static int
113ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos)
114{
115 struct super_block *sb = inode->i_sb;
116 int blockmask = sb->s_blocksize - 1;
117
118 if (pos >= i_size_read(inode))
119 return 0;
120
121 if ((pos | iov_iter_alignment(from)) & blockmask)
122 return 1;
123
124 return 0;
125}
126
127/* Is IO overwriting allocated and initialized blocks? */
128static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
129{
130 struct ext4_map_blocks map;
131 unsigned int blkbits = inode->i_blkbits;
132 int err, blklen;
133
134 if (pos + len > i_size_read(inode))
135 return false;
136
137 map.m_lblk = pos >> blkbits;
138 map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
139 blklen = map.m_len;
140
141 err = ext4_map_blocks(NULL, inode, &map, 0);
142 /*
143 * 'err==len' means that all of the blocks have been preallocated,
144 * regardless of whether they have been initialized or not. To exclude
145 * unwritten extents, we need to check m_flags.
146 */
147 return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
148}
149
150static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
151{
152 struct inode *inode = file_inode(iocb->ki_filp);
153 ssize_t ret;
154
155 ret = generic_write_checks(iocb, from);
156 if (ret <= 0)
157 return ret;
158 /*
159 * If we have encountered a bitmap-format file, the size limit
160 * is smaller than s_maxbytes, which is for extent-mapped files.
161 */
162 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
163 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
164
165 if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
166 return -EFBIG;
167 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
168 }
169 return iov_iter_count(from);
170}
171
172#ifdef CONFIG_FS_DAX
173static ssize_t
174ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
175{
176 struct inode *inode = file_inode(iocb->ki_filp);
177 ssize_t ret;
178 bool overwrite = false;
179
180 inode_lock(inode);
181 ret = ext4_write_checks(iocb, from);
182 if (ret <= 0)
183 goto out;
184 ret = file_remove_privs(iocb->ki_filp);
185 if (ret)
186 goto out;
187 ret = file_update_time(iocb->ki_filp);
188 if (ret)
189 goto out;
190
191 if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) {
192 overwrite = true;
193 downgrade_write(&inode->i_rwsem);
194 }
195 ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
196out:
197 if (!overwrite)
198 inode_unlock(inode);
199 else
200 inode_unlock_shared(inode);
201 if (ret > 0)
202 ret = generic_write_sync(iocb, ret);
203 return ret;
204}
205#endif
206
207static ssize_t
208ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
209{
210 struct inode *inode = file_inode(iocb->ki_filp);
211 int o_direct = iocb->ki_flags & IOCB_DIRECT;
212 int unaligned_aio = 0;
213 int overwrite = 0;
214 ssize_t ret;
215
216#ifdef CONFIG_FS_DAX
217 if (IS_DAX(inode))
218 return ext4_dax_write_iter(iocb, from);
219#endif
220
221 inode_lock(inode);
222 ret = ext4_write_checks(iocb, from);
223 if (ret <= 0)
224 goto out;
225
226 /*
227 * Unaligned direct AIO must be serialized among each other as zeroing
228 * of partial blocks of two competing unaligned AIOs can result in data
229 * corruption.
230 */
231 if (o_direct && ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
232 !is_sync_kiocb(iocb) &&
233 ext4_unaligned_aio(inode, from, iocb->ki_pos)) {
234 unaligned_aio = 1;
235 ext4_unwritten_wait(inode);
236 }
237
238 iocb->private = &overwrite;
239 /* Check whether we do a DIO overwrite or not */
240 if (o_direct && ext4_should_dioread_nolock(inode) && !unaligned_aio &&
241 ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from)))
242 overwrite = 1;
243
244 ret = __generic_file_write_iter(iocb, from);
245 inode_unlock(inode);
246
247 if (ret > 0)
248 ret = generic_write_sync(iocb, ret);
249
250 return ret;
251
252out:
253 inode_unlock(inode);
254 return ret;
255}
256
257#ifdef CONFIG_FS_DAX
258static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
259{
260 int result;
261 struct inode *inode = file_inode(vma->vm_file);
262 struct super_block *sb = inode->i_sb;
263 bool write = vmf->flags & FAULT_FLAG_WRITE;
264
265 if (write) {
266 sb_start_pagefault(sb);
267 file_update_time(vma->vm_file);
268 }
269 down_read(&EXT4_I(inode)->i_mmap_sem);
270 result = dax_iomap_fault(vma, vmf, &ext4_iomap_ops);
271 up_read(&EXT4_I(inode)->i_mmap_sem);
272 if (write)
273 sb_end_pagefault(sb);
274
275 return result;
276}
277
278static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
279 pmd_t *pmd, unsigned int flags)
280{
281 int result;
282 struct inode *inode = file_inode(vma->vm_file);
283 struct super_block *sb = inode->i_sb;
284 bool write = flags & FAULT_FLAG_WRITE;
285
286 if (write) {
287 sb_start_pagefault(sb);
288 file_update_time(vma->vm_file);
289 }
290 down_read(&EXT4_I(inode)->i_mmap_sem);
291 result = dax_iomap_pmd_fault(vma, addr, pmd, flags,
292 &ext4_iomap_ops);
293 up_read(&EXT4_I(inode)->i_mmap_sem);
294 if (write)
295 sb_end_pagefault(sb);
296
297 return result;
298}
299
300/*
301 * Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_fault()
302 * handler we check for races agaist truncate. Note that since we cycle through
303 * i_mmap_sem, we are sure that also any hole punching that began before we
304 * were called is finished by now and so if it included part of the file we
305 * are working on, our pte will get unmapped and the check for pte_same() in
306 * wp_pfn_shared() fails. Thus fault gets retried and things work out as
307 * desired.
308 */
309static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma,
310 struct vm_fault *vmf)
311{
312 struct inode *inode = file_inode(vma->vm_file);
313 struct super_block *sb = inode->i_sb;
314 loff_t size;
315 int ret;
316
317 sb_start_pagefault(sb);
318 file_update_time(vma->vm_file);
319 down_read(&EXT4_I(inode)->i_mmap_sem);
320 size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
321 if (vmf->pgoff >= size)
322 ret = VM_FAULT_SIGBUS;
323 else
324 ret = dax_pfn_mkwrite(vma, vmf);
325 up_read(&EXT4_I(inode)->i_mmap_sem);
326 sb_end_pagefault(sb);
327
328 return ret;
329}
330
331static const struct vm_operations_struct ext4_dax_vm_ops = {
332 .fault = ext4_dax_fault,
333 .pmd_fault = ext4_dax_pmd_fault,
334 .page_mkwrite = ext4_dax_fault,
335 .pfn_mkwrite = ext4_dax_pfn_mkwrite,
336};
337#else
338#define ext4_dax_vm_ops ext4_file_vm_ops
339#endif
340
341static const struct vm_operations_struct ext4_file_vm_ops = {
342 .fault = ext4_filemap_fault,
343 .map_pages = filemap_map_pages,
344 .page_mkwrite = ext4_page_mkwrite,
345};
346
347static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
348{
349 struct inode *inode = file->f_mapping->host;
350
351 if (ext4_encrypted_inode(inode)) {
352 int err = fscrypt_get_encryption_info(inode);
353 if (err)
354 return 0;
355 if (!fscrypt_has_encryption_key(inode))
356 return -ENOKEY;
357 }
358 file_accessed(file);
359 if (IS_DAX(file_inode(file))) {
360 vma->vm_ops = &ext4_dax_vm_ops;
361 vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
362 } else {
363 vma->vm_ops = &ext4_file_vm_ops;
364 }
365 return 0;
366}
367
368static int ext4_file_open(struct inode * inode, struct file * filp)
369{
370 struct super_block *sb = inode->i_sb;
371 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
372 struct vfsmount *mnt = filp->f_path.mnt;
373 struct dentry *dir;
374 struct path path;
375 char buf[64], *cp;
376 int ret;
377
378 if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
379 !(sb->s_flags & MS_RDONLY))) {
380 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
381 /*
382 * Sample where the filesystem has been mounted and
383 * store it in the superblock for sysadmin convenience
384 * when trying to sort through large numbers of block
385 * devices or filesystem images.
386 */
387 memset(buf, 0, sizeof(buf));
388 path.mnt = mnt;
389 path.dentry = mnt->mnt_root;
390 cp = d_path(&path, buf, sizeof(buf));
391 if (!IS_ERR(cp)) {
392 handle_t *handle;
393 int err;
394
395 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
396 if (IS_ERR(handle))
397 return PTR_ERR(handle);
398 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
399 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
400 if (err) {
401 ext4_journal_stop(handle);
402 return err;
403 }
404 strlcpy(sbi->s_es->s_last_mounted, cp,
405 sizeof(sbi->s_es->s_last_mounted));
406 ext4_handle_dirty_super(handle, sb);
407 ext4_journal_stop(handle);
408 }
409 }
410 if (ext4_encrypted_inode(inode)) {
411 ret = fscrypt_get_encryption_info(inode);
412 if (ret)
413 return -EACCES;
414 if (!fscrypt_has_encryption_key(inode))
415 return -ENOKEY;
416 }
417
418 dir = dget_parent(file_dentry(filp));
419 if (ext4_encrypted_inode(d_inode(dir)) &&
420 !fscrypt_has_permitted_context(d_inode(dir), inode)) {
421 ext4_warning(inode->i_sb,
422 "Inconsistent encryption contexts: %lu/%lu",
423 (unsigned long) d_inode(dir)->i_ino,
424 (unsigned long) inode->i_ino);
425 dput(dir);
426 return -EPERM;
427 }
428 dput(dir);
429 /*
430 * Set up the jbd2_inode if we are opening the inode for
431 * writing and the journal is present
432 */
433 if (filp->f_mode & FMODE_WRITE) {
434 ret = ext4_inode_attach_jinode(inode);
435 if (ret < 0)
436 return ret;
437 }
438 return dquot_file_open(inode, filp);
439}
440
441/*
442 * Here we use ext4_map_blocks() to get a block mapping for a extent-based
443 * file rather than ext4_ext_walk_space() because we can introduce
444 * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
445 * function. When extent status tree has been fully implemented, it will
446 * track all extent status for a file and we can directly use it to
447 * retrieve the offset for SEEK_DATA/SEEK_HOLE.
448 */
449
450/*
451 * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
452 * lookup page cache to check whether or not there has some data between
453 * [startoff, endoff] because, if this range contains an unwritten extent,
454 * we determine this extent as a data or a hole according to whether the
455 * page cache has data or not.
456 */
457static int ext4_find_unwritten_pgoff(struct inode *inode,
458 int whence,
459 ext4_lblk_t end_blk,
460 loff_t *offset)
461{
462 struct pagevec pvec;
463 unsigned int blkbits;
464 pgoff_t index;
465 pgoff_t end;
466 loff_t endoff;
467 loff_t startoff;
468 loff_t lastoff;
469 int found = 0;
470
471 blkbits = inode->i_sb->s_blocksize_bits;
472 startoff = *offset;
473 lastoff = startoff;
474 endoff = (loff_t)end_blk << blkbits;
475
476 index = startoff >> PAGE_SHIFT;
477 end = endoff >> PAGE_SHIFT;
478
479 pagevec_init(&pvec, 0);
480 do {
481 int i, num;
482 unsigned long nr_pages;
483
484 num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
485 nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
486 (pgoff_t)num);
487 if (nr_pages == 0) {
488 if (whence == SEEK_DATA)
489 break;
490
491 BUG_ON(whence != SEEK_HOLE);
492 /*
493 * If this is the first time to go into the loop and
494 * offset is not beyond the end offset, it will be a
495 * hole at this offset
496 */
497 if (lastoff == startoff || lastoff < endoff)
498 found = 1;
499 break;
500 }
501
502 /*
503 * If this is the first time to go into the loop and
504 * offset is smaller than the first page offset, it will be a
505 * hole at this offset.
506 */
507 if (lastoff == startoff && whence == SEEK_HOLE &&
508 lastoff < page_offset(pvec.pages[0])) {
509 found = 1;
510 break;
511 }
512
513 for (i = 0; i < nr_pages; i++) {
514 struct page *page = pvec.pages[i];
515 struct buffer_head *bh, *head;
516
517 /*
518 * If the current offset is not beyond the end of given
519 * range, it will be a hole.
520 */
521 if (lastoff < endoff && whence == SEEK_HOLE &&
522 page->index > end) {
523 found = 1;
524 *offset = lastoff;
525 goto out;
526 }
527
528 lock_page(page);
529
530 if (unlikely(page->mapping != inode->i_mapping)) {
531 unlock_page(page);
532 continue;
533 }
534
535 if (!page_has_buffers(page)) {
536 unlock_page(page);
537 continue;
538 }
539
540 if (page_has_buffers(page)) {
541 lastoff = page_offset(page);
542 bh = head = page_buffers(page);
543 do {
544 if (buffer_uptodate(bh) ||
545 buffer_unwritten(bh)) {
546 if (whence == SEEK_DATA)
547 found = 1;
548 } else {
549 if (whence == SEEK_HOLE)
550 found = 1;
551 }
552 if (found) {
553 *offset = max_t(loff_t,
554 startoff, lastoff);
555 unlock_page(page);
556 goto out;
557 }
558 lastoff += bh->b_size;
559 bh = bh->b_this_page;
560 } while (bh != head);
561 }
562
563 lastoff = page_offset(page) + PAGE_SIZE;
564 unlock_page(page);
565 }
566
567 /*
568 * The no. of pages is less than our desired, that would be a
569 * hole in there.
570 */
571 if (nr_pages < num && whence == SEEK_HOLE) {
572 found = 1;
573 *offset = lastoff;
574 break;
575 }
576
577 index = pvec.pages[i - 1]->index + 1;
578 pagevec_release(&pvec);
579 } while (index <= end);
580
581out:
582 pagevec_release(&pvec);
583 return found;
584}
585
586/*
587 * ext4_seek_data() retrieves the offset for SEEK_DATA.
588 */
589static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
590{
591 struct inode *inode = file->f_mapping->host;
592 struct extent_status es;
593 ext4_lblk_t start, last, end;
594 loff_t dataoff, isize;
595 int blkbits;
596 int ret;
597
598 inode_lock(inode);
599
600 isize = i_size_read(inode);
601 if (offset >= isize) {
602 inode_unlock(inode);
603 return -ENXIO;
604 }
605
606 blkbits = inode->i_sb->s_blocksize_bits;
607 start = offset >> blkbits;
608 last = start;
609 end = isize >> blkbits;
610 dataoff = offset;
611
612 do {
613 ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
614 if (ret <= 0) {
615 /* No extent found -> no data */
616 if (ret == 0)
617 ret = -ENXIO;
618 inode_unlock(inode);
619 return ret;
620 }
621
622 last = es.es_lblk;
623 if (last != start)
624 dataoff = (loff_t)last << blkbits;
625 if (!ext4_es_is_unwritten(&es))
626 break;
627
628 /*
629 * If there is a unwritten extent at this offset,
630 * it will be as a data or a hole according to page
631 * cache that has data or not.
632 */
633 if (ext4_find_unwritten_pgoff(inode, SEEK_DATA,
634 es.es_lblk + es.es_len, &dataoff))
635 break;
636 last += es.es_len;
637 dataoff = (loff_t)last << blkbits;
638 cond_resched();
639 } while (last <= end);
640
641 inode_unlock(inode);
642
643 if (dataoff > isize)
644 return -ENXIO;
645
646 return vfs_setpos(file, dataoff, maxsize);
647}
648
649/*
650 * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
651 */
652static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
653{
654 struct inode *inode = file->f_mapping->host;
655 struct extent_status es;
656 ext4_lblk_t start, last, end;
657 loff_t holeoff, isize;
658 int blkbits;
659 int ret;
660
661 inode_lock(inode);
662
663 isize = i_size_read(inode);
664 if (offset >= isize) {
665 inode_unlock(inode);
666 return -ENXIO;
667 }
668
669 blkbits = inode->i_sb->s_blocksize_bits;
670 start = offset >> blkbits;
671 last = start;
672 end = isize >> blkbits;
673 holeoff = offset;
674
675 do {
676 ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
677 if (ret < 0) {
678 inode_unlock(inode);
679 return ret;
680 }
681 /* Found a hole? */
682 if (ret == 0 || es.es_lblk > last) {
683 if (last != start)
684 holeoff = (loff_t)last << blkbits;
685 break;
686 }
687 /*
688 * If there is a unwritten extent at this offset,
689 * it will be as a data or a hole according to page
690 * cache that has data or not.
691 */
692 if (ext4_es_is_unwritten(&es) &&
693 ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
694 last + es.es_len, &holeoff))
695 break;
696
697 last += es.es_len;
698 holeoff = (loff_t)last << blkbits;
699 cond_resched();
700 } while (last <= end);
701
702 inode_unlock(inode);
703
704 if (holeoff > isize)
705 holeoff = isize;
706
707 return vfs_setpos(file, holeoff, maxsize);
708}
709
710/*
711 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
712 * by calling generic_file_llseek_size() with the appropriate maxbytes
713 * value for each.
714 */
715loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
716{
717 struct inode *inode = file->f_mapping->host;
718 loff_t maxbytes;
719
720 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
721 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
722 else
723 maxbytes = inode->i_sb->s_maxbytes;
724
725 switch (whence) {
726 case SEEK_SET:
727 case SEEK_CUR:
728 case SEEK_END:
729 return generic_file_llseek_size(file, offset, whence,
730 maxbytes, i_size_read(inode));
731 case SEEK_DATA:
732 return ext4_seek_data(file, offset, maxbytes);
733 case SEEK_HOLE:
734 return ext4_seek_hole(file, offset, maxbytes);
735 }
736
737 return -EINVAL;
738}
739
740const struct file_operations ext4_file_operations = {
741 .llseek = ext4_llseek,
742 .read_iter = ext4_file_read_iter,
743 .write_iter = ext4_file_write_iter,
744 .unlocked_ioctl = ext4_ioctl,
745#ifdef CONFIG_COMPAT
746 .compat_ioctl = ext4_compat_ioctl,
747#endif
748 .mmap = ext4_file_mmap,
749 .open = ext4_file_open,
750 .release = ext4_release_file,
751 .fsync = ext4_sync_file,
752 .get_unmapped_area = thp_get_unmapped_area,
753 .splice_read = generic_file_splice_read,
754 .splice_write = iter_file_splice_write,
755 .fallocate = ext4_fallocate,
756};
757
758const struct inode_operations ext4_file_inode_operations = {
759 .setattr = ext4_setattr,
760 .getattr = ext4_getattr,
761 .listxattr = ext4_listxattr,
762 .get_acl = ext4_get_acl,
763 .set_acl = ext4_set_acl,
764 .fiemap = ext4_fiemap,
765};
766
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
39static 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
52static 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,
78 is_sync_kiocb(iocb));
79 inode_unlock_shared(inode);
80
81 file_accessed(iocb->ki_filp);
82 return ret;
83}
84
85#ifdef CONFIG_FS_DAX
86static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
87{
88 struct inode *inode = file_inode(iocb->ki_filp);
89 ssize_t ret;
90
91 if (iocb->ki_flags & IOCB_NOWAIT) {
92 if (!inode_trylock_shared(inode))
93 return -EAGAIN;
94 } else {
95 inode_lock_shared(inode);
96 }
97 /*
98 * Recheck under inode lock - at this point we are sure it cannot
99 * change anymore
100 */
101 if (!IS_DAX(inode)) {
102 inode_unlock_shared(inode);
103 /* Fallback to buffered IO in case we cannot support DAX */
104 return generic_file_read_iter(iocb, to);
105 }
106 ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
107 inode_unlock_shared(inode);
108
109 file_accessed(iocb->ki_filp);
110 return ret;
111}
112#endif
113
114static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
115{
116 struct inode *inode = file_inode(iocb->ki_filp);
117
118 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
119 return -EIO;
120
121 if (!iov_iter_count(to))
122 return 0; /* skip atime */
123
124#ifdef CONFIG_FS_DAX
125 if (IS_DAX(inode))
126 return ext4_dax_read_iter(iocb, to);
127#endif
128 if (iocb->ki_flags & IOCB_DIRECT)
129 return ext4_dio_read_iter(iocb, to);
130
131 return generic_file_read_iter(iocb, to);
132}
133
134/*
135 * Called when an inode is released. Note that this is different
136 * from ext4_file_open: open gets called at every open, but release
137 * gets called only when /all/ the files are closed.
138 */
139static int ext4_release_file(struct inode *inode, struct file *filp)
140{
141 if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
142 ext4_alloc_da_blocks(inode);
143 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
144 }
145 /* if we are the last writer on the inode, drop the block reservation */
146 if ((filp->f_mode & FMODE_WRITE) &&
147 (atomic_read(&inode->i_writecount) == 1) &&
148 !EXT4_I(inode)->i_reserved_data_blocks) {
149 down_write(&EXT4_I(inode)->i_data_sem);
150 ext4_discard_preallocations(inode, 0);
151 up_write(&EXT4_I(inode)->i_data_sem);
152 }
153 if (is_dx(inode) && filp->private_data)
154 ext4_htree_free_dir_info(filp->private_data);
155
156 return 0;
157}
158
159/*
160 * This tests whether the IO in question is block-aligned or not.
161 * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
162 * are converted to written only after the IO is complete. Until they are
163 * mapped, these blocks appear as holes, so dio_zero_block() will assume that
164 * it needs to zero out portions of the start and/or end block. If 2 AIO
165 * threads are at work on the same unwritten block, they must be synchronized
166 * or one thread will zero the other's data, causing corruption.
167 */
168static bool
169ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
170{
171 struct super_block *sb = inode->i_sb;
172 unsigned long blockmask = sb->s_blocksize - 1;
173
174 if ((pos | iov_iter_alignment(from)) & blockmask)
175 return true;
176
177 return false;
178}
179
180static bool
181ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
182{
183 if (offset + len > i_size_read(inode) ||
184 offset + len > EXT4_I(inode)->i_disksize)
185 return true;
186 return false;
187}
188
189/* Is IO overwriting allocated and initialized blocks? */
190static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
191{
192 struct ext4_map_blocks map;
193 unsigned int blkbits = inode->i_blkbits;
194 int err, blklen;
195
196 if (pos + len > i_size_read(inode))
197 return false;
198
199 map.m_lblk = pos >> blkbits;
200 map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
201 blklen = map.m_len;
202
203 err = ext4_map_blocks(NULL, inode, &map, 0);
204 /*
205 * 'err==len' means that all of the blocks have been preallocated,
206 * regardless of whether they have been initialized or not. To exclude
207 * unwritten extents, we need to check m_flags.
208 */
209 return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
210}
211
212static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
213 struct iov_iter *from)
214{
215 struct inode *inode = file_inode(iocb->ki_filp);
216 ssize_t ret;
217
218 if (unlikely(IS_IMMUTABLE(inode)))
219 return -EPERM;
220
221 ret = generic_write_checks(iocb, from);
222 if (ret <= 0)
223 return ret;
224
225 /*
226 * If we have encountered a bitmap-format file, the size limit
227 * is smaller than s_maxbytes, which is for extent-mapped files.
228 */
229 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
230 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
231
232 if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
233 return -EFBIG;
234 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
235 }
236
237 return iov_iter_count(from);
238}
239
240static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
241{
242 ssize_t ret, count;
243
244 count = ext4_generic_write_checks(iocb, from);
245 if (count <= 0)
246 return count;
247
248 ret = file_modified(iocb->ki_filp);
249 if (ret)
250 return ret;
251 return count;
252}
253
254static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
255 struct iov_iter *from)
256{
257 ssize_t ret;
258 struct inode *inode = file_inode(iocb->ki_filp);
259
260 if (iocb->ki_flags & IOCB_NOWAIT)
261 return -EOPNOTSUPP;
262
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
272out:
273 inode_unlock(inode);
274 if (likely(ret > 0)) {
275 iocb->ki_pos += ret;
276 ret = generic_write_sync(iocb, ret);
277 }
278
279 return ret;
280}
281
282static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
283 ssize_t written, size_t count)
284{
285 handle_t *handle;
286 bool truncate = false;
287 u8 blkbits = inode->i_blkbits;
288 ext4_lblk_t written_blk, end_blk;
289 int ret;
290
291 /*
292 * Note that EXT4_I(inode)->i_disksize can get extended up to
293 * inode->i_size while the I/O was running due to writeback of delalloc
294 * blocks. But, the code in ext4_iomap_alloc() is careful to use
295 * zeroed/unwritten extents if this is possible; thus we won't leave
296 * uninitialized blocks in a file even if we didn't succeed in writing
297 * as much as we intended.
298 */
299 WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
300 if (offset + count <= EXT4_I(inode)->i_disksize) {
301 /*
302 * We need to ensure that the inode is removed from the orphan
303 * list if it has been added prematurely, due to writeback of
304 * delalloc blocks.
305 */
306 if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
307 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
308
309 if (IS_ERR(handle)) {
310 ext4_orphan_del(NULL, inode);
311 return PTR_ERR(handle);
312 }
313
314 ext4_orphan_del(handle, inode);
315 ext4_journal_stop(handle);
316 }
317
318 return written;
319 }
320
321 if (written < 0)
322 goto truncate;
323
324 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
325 if (IS_ERR(handle)) {
326 written = PTR_ERR(handle);
327 goto truncate;
328 }
329
330 if (ext4_update_inode_size(inode, offset + written)) {
331 ret = ext4_mark_inode_dirty(handle, inode);
332 if (unlikely(ret)) {
333 written = ret;
334 ext4_journal_stop(handle);
335 goto truncate;
336 }
337 }
338
339 /*
340 * We may need to truncate allocated but not written blocks beyond EOF.
341 */
342 written_blk = ALIGN(offset + written, 1 << blkbits);
343 end_blk = ALIGN(offset + count, 1 << blkbits);
344 if (written_blk < end_blk && ext4_can_truncate(inode))
345 truncate = true;
346
347 /*
348 * Remove the inode from the orphan list if it has been extended and
349 * everything went OK.
350 */
351 if (!truncate && inode->i_nlink)
352 ext4_orphan_del(handle, inode);
353 ext4_journal_stop(handle);
354
355 if (truncate) {
356truncate:
357 ext4_truncate_failed_write(inode);
358 /*
359 * If the truncate operation failed early, then the inode may
360 * still be on the orphan list. In that case, we need to try
361 * remove the inode from the in-memory linked list.
362 */
363 if (inode->i_nlink)
364 ext4_orphan_del(NULL, inode);
365 }
366
367 return written;
368}
369
370static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
371 int error, unsigned int flags)
372{
373 loff_t offset = iocb->ki_pos;
374 struct inode *inode = file_inode(iocb->ki_filp);
375
376 if (error)
377 return error;
378
379 if (size && flags & IOMAP_DIO_UNWRITTEN)
380 return ext4_convert_unwritten_extents(NULL, inode,
381 offset, size);
382
383 return 0;
384}
385
386static const struct iomap_dio_ops ext4_dio_write_ops = {
387 .end_io = ext4_dio_write_end_io,
388};
389
390/*
391 * The intention here is to start with shared lock acquired then see if any
392 * condition requires an exclusive inode lock. If yes, then we restart the
393 * whole operation by releasing the shared lock and acquiring exclusive lock.
394 *
395 * - For unaligned_io we never take shared lock as it may cause data corruption
396 * when two unaligned IO tries to modify the same block e.g. while zeroing.
397 *
398 * - For extending writes case we don't take the shared lock, since it requires
399 * updating inode i_disksize and/or orphan handling with exclusive lock.
400 *
401 * - shared locking will only be true mostly with overwrites. Otherwise we will
402 * switch to exclusive i_rwsem lock.
403 */
404static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
405 bool *ilock_shared, bool *extend)
406{
407 struct file *file = iocb->ki_filp;
408 struct inode *inode = file_inode(file);
409 loff_t offset;
410 size_t count;
411 ssize_t ret;
412
413restart:
414 ret = ext4_generic_write_checks(iocb, from);
415 if (ret <= 0)
416 goto out;
417
418 offset = iocb->ki_pos;
419 count = ret;
420 if (ext4_extending_io(inode, offset, count))
421 *extend = true;
422 /*
423 * Determine whether the IO operation will overwrite allocated
424 * and initialized blocks.
425 * We need exclusive i_rwsem for changing security info
426 * in file_modified().
427 */
428 if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
429 !ext4_overwrite_io(inode, offset, count))) {
430 if (iocb->ki_flags & IOCB_NOWAIT) {
431 ret = -EAGAIN;
432 goto out;
433 }
434 inode_unlock_shared(inode);
435 *ilock_shared = false;
436 inode_lock(inode);
437 goto restart;
438 }
439
440 ret = file_modified(file);
441 if (ret < 0)
442 goto out;
443
444 return count;
445out:
446 if (*ilock_shared)
447 inode_unlock_shared(inode);
448 else
449 inode_unlock(inode);
450 return ret;
451}
452
453static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
454{
455 ssize_t ret;
456 handle_t *handle;
457 struct inode *inode = file_inode(iocb->ki_filp);
458 loff_t offset = iocb->ki_pos;
459 size_t count = iov_iter_count(from);
460 const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
461 bool extend = false, unaligned_io = false;
462 bool ilock_shared = true;
463
464 /*
465 * We initially start with shared inode lock unless it is
466 * unaligned IO which needs exclusive lock anyways.
467 */
468 if (ext4_unaligned_io(inode, from, offset)) {
469 unaligned_io = true;
470 ilock_shared = false;
471 }
472 /*
473 * Quick check here without any i_rwsem lock to see if it is extending
474 * IO. A more reliable check is done in ext4_dio_write_checks() with
475 * proper locking in place.
476 */
477 if (offset + count > i_size_read(inode))
478 ilock_shared = false;
479
480 if (iocb->ki_flags & IOCB_NOWAIT) {
481 if (ilock_shared) {
482 if (!inode_trylock_shared(inode))
483 return -EAGAIN;
484 } else {
485 if (!inode_trylock(inode))
486 return -EAGAIN;
487 }
488 } else {
489 if (ilock_shared)
490 inode_lock_shared(inode);
491 else
492 inode_lock(inode);
493 }
494
495 /* Fallback to buffered I/O if the inode does not support direct I/O. */
496 if (!ext4_dio_supported(inode)) {
497 if (ilock_shared)
498 inode_unlock_shared(inode);
499 else
500 inode_unlock(inode);
501 return ext4_buffered_write_iter(iocb, from);
502 }
503
504 ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
505 if (ret <= 0)
506 return ret;
507
508 /* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
509 if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
510 ret = -EAGAIN;
511 goto out;
512 }
513
514 offset = iocb->ki_pos;
515 count = ret;
516
517 /*
518 * Unaligned direct IO must be serialized among each other as zeroing
519 * of partial blocks of two competing unaligned IOs can result in data
520 * corruption.
521 *
522 * So we make sure we don't allow any unaligned IO in flight.
523 * For IOs where we need not wait (like unaligned non-AIO DIO),
524 * below inode_dio_wait() may anyway become a no-op, since we start
525 * with exclusive lock.
526 */
527 if (unaligned_io)
528 inode_dio_wait(inode);
529
530 if (extend) {
531 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
532 if (IS_ERR(handle)) {
533 ret = PTR_ERR(handle);
534 goto out;
535 }
536
537 ret = ext4_orphan_add(handle, inode);
538 if (ret) {
539 ext4_journal_stop(handle);
540 goto out;
541 }
542
543 ext4_journal_stop(handle);
544 }
545
546 if (ilock_shared)
547 iomap_ops = &ext4_iomap_overwrite_ops;
548 ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
549 is_sync_kiocb(iocb) || unaligned_io || extend);
550 if (ret == -ENOTBLK)
551 ret = 0;
552
553 if (extend)
554 ret = ext4_handle_inode_extension(inode, offset, ret, count);
555
556out:
557 if (ilock_shared)
558 inode_unlock_shared(inode);
559 else
560 inode_unlock(inode);
561
562 if (ret >= 0 && iov_iter_count(from)) {
563 ssize_t err;
564 loff_t endbyte;
565
566 offset = iocb->ki_pos;
567 err = ext4_buffered_write_iter(iocb, from);
568 if (err < 0)
569 return err;
570
571 /*
572 * We need to ensure that the pages within the page cache for
573 * the range covered by this I/O are written to disk and
574 * invalidated. This is in attempt to preserve the expected
575 * direct I/O semantics in the case we fallback to buffered I/O
576 * to complete off the I/O request.
577 */
578 ret += err;
579 endbyte = offset + err - 1;
580 err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
581 offset, endbyte);
582 if (!err)
583 invalidate_mapping_pages(iocb->ki_filp->f_mapping,
584 offset >> PAGE_SHIFT,
585 endbyte >> PAGE_SHIFT);
586 }
587
588 return ret;
589}
590
591#ifdef CONFIG_FS_DAX
592static ssize_t
593ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
594{
595 ssize_t ret;
596 size_t count;
597 loff_t offset;
598 handle_t *handle;
599 bool extend = false;
600 struct inode *inode = file_inode(iocb->ki_filp);
601
602 if (iocb->ki_flags & IOCB_NOWAIT) {
603 if (!inode_trylock(inode))
604 return -EAGAIN;
605 } else {
606 inode_lock(inode);
607 }
608
609 ret = ext4_write_checks(iocb, from);
610 if (ret <= 0)
611 goto out;
612
613 offset = iocb->ki_pos;
614 count = iov_iter_count(from);
615
616 if (offset + count > EXT4_I(inode)->i_disksize) {
617 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
618 if (IS_ERR(handle)) {
619 ret = PTR_ERR(handle);
620 goto out;
621 }
622
623 ret = ext4_orphan_add(handle, inode);
624 if (ret) {
625 ext4_journal_stop(handle);
626 goto out;
627 }
628
629 extend = true;
630 ext4_journal_stop(handle);
631 }
632
633 ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
634
635 if (extend)
636 ret = ext4_handle_inode_extension(inode, offset, ret, count);
637out:
638 inode_unlock(inode);
639 if (ret > 0)
640 ret = generic_write_sync(iocb, ret);
641 return ret;
642}
643#endif
644
645static ssize_t
646ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
647{
648 struct inode *inode = file_inode(iocb->ki_filp);
649
650 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
651 return -EIO;
652
653#ifdef CONFIG_FS_DAX
654 if (IS_DAX(inode))
655 return ext4_dax_write_iter(iocb, from);
656#endif
657 if (iocb->ki_flags & IOCB_DIRECT)
658 return ext4_dio_write_iter(iocb, from);
659
660 return ext4_buffered_write_iter(iocb, from);
661}
662
663#ifdef CONFIG_FS_DAX
664static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
665 enum page_entry_size pe_size)
666{
667 int error = 0;
668 vm_fault_t result;
669 int retries = 0;
670 handle_t *handle = NULL;
671 struct inode *inode = file_inode(vmf->vma->vm_file);
672 struct super_block *sb = inode->i_sb;
673
674 /*
675 * We have to distinguish real writes from writes which will result in a
676 * COW page; COW writes should *not* poke the journal (the file will not
677 * be changed). Doing so would cause unintended failures when mounted
678 * read-only.
679 *
680 * We check for VM_SHARED rather than vmf->cow_page since the latter is
681 * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
682 * other sizes, dax_iomap_fault will handle splitting / fallback so that
683 * we eventually come back with a COW page.
684 */
685 bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
686 (vmf->vma->vm_flags & VM_SHARED);
687 pfn_t pfn;
688
689 if (write) {
690 sb_start_pagefault(sb);
691 file_update_time(vmf->vma->vm_file);
692 down_read(&EXT4_I(inode)->i_mmap_sem);
693retry:
694 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
695 EXT4_DATA_TRANS_BLOCKS(sb));
696 if (IS_ERR(handle)) {
697 up_read(&EXT4_I(inode)->i_mmap_sem);
698 sb_end_pagefault(sb);
699 return VM_FAULT_SIGBUS;
700 }
701 } else {
702 down_read(&EXT4_I(inode)->i_mmap_sem);
703 }
704 result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
705 if (write) {
706 ext4_journal_stop(handle);
707
708 if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
709 ext4_should_retry_alloc(sb, &retries))
710 goto retry;
711 /* Handling synchronous page fault? */
712 if (result & VM_FAULT_NEEDDSYNC)
713 result = dax_finish_sync_fault(vmf, pe_size, pfn);
714 up_read(&EXT4_I(inode)->i_mmap_sem);
715 sb_end_pagefault(sb);
716 } else {
717 up_read(&EXT4_I(inode)->i_mmap_sem);
718 }
719
720 return result;
721}
722
723static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
724{
725 return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
726}
727
728static const struct vm_operations_struct ext4_dax_vm_ops = {
729 .fault = ext4_dax_fault,
730 .huge_fault = ext4_dax_huge_fault,
731 .page_mkwrite = ext4_dax_fault,
732 .pfn_mkwrite = ext4_dax_fault,
733};
734#else
735#define ext4_dax_vm_ops ext4_file_vm_ops
736#endif
737
738static const struct vm_operations_struct ext4_file_vm_ops = {
739 .fault = ext4_filemap_fault,
740 .map_pages = filemap_map_pages,
741 .page_mkwrite = ext4_page_mkwrite,
742};
743
744static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
745{
746 struct inode *inode = file->f_mapping->host;
747 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
748 struct dax_device *dax_dev = sbi->s_daxdev;
749
750 if (unlikely(ext4_forced_shutdown(sbi)))
751 return -EIO;
752
753 /*
754 * We don't support synchronous mappings for non-DAX files and
755 * for DAX files if underneath dax_device is not synchronous.
756 */
757 if (!daxdev_mapping_supported(vma, dax_dev))
758 return -EOPNOTSUPP;
759
760 file_accessed(file);
761 if (IS_DAX(file_inode(file))) {
762 vma->vm_ops = &ext4_dax_vm_ops;
763 vma->vm_flags |= VM_HUGEPAGE;
764 } else {
765 vma->vm_ops = &ext4_file_vm_ops;
766 }
767 return 0;
768}
769
770static int ext4_sample_last_mounted(struct super_block *sb,
771 struct vfsmount *mnt)
772{
773 struct ext4_sb_info *sbi = EXT4_SB(sb);
774 struct path path;
775 char buf[64], *cp;
776 handle_t *handle;
777 int err;
778
779 if (likely(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED))
780 return 0;
781
782 if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
783 return 0;
784
785 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
786 /*
787 * Sample where the filesystem has been mounted and
788 * store it in the superblock for sysadmin convenience
789 * when trying to sort through large numbers of block
790 * devices or filesystem images.
791 */
792 memset(buf, 0, sizeof(buf));
793 path.mnt = mnt;
794 path.dentry = mnt->mnt_root;
795 cp = d_path(&path, buf, sizeof(buf));
796 err = 0;
797 if (IS_ERR(cp))
798 goto out;
799
800 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
801 err = PTR_ERR(handle);
802 if (IS_ERR(handle))
803 goto out;
804 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
805 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
806 if (err)
807 goto out_journal;
808 strlcpy(sbi->s_es->s_last_mounted, cp,
809 sizeof(sbi->s_es->s_last_mounted));
810 ext4_handle_dirty_super(handle, sb);
811out_journal:
812 ext4_journal_stop(handle);
813out:
814 sb_end_intwrite(sb);
815 return err;
816}
817
818static int ext4_file_open(struct inode *inode, struct file *filp)
819{
820 int ret;
821
822 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
823 return -EIO;
824
825 ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
826 if (ret)
827 return ret;
828
829 ret = fscrypt_file_open(inode, filp);
830 if (ret)
831 return ret;
832
833 ret = fsverity_file_open(inode, filp);
834 if (ret)
835 return ret;
836
837 /*
838 * Set up the jbd2_inode if we are opening the inode for
839 * writing and the journal is present
840 */
841 if (filp->f_mode & FMODE_WRITE) {
842 ret = ext4_inode_attach_jinode(inode);
843 if (ret < 0)
844 return ret;
845 }
846
847 filp->f_mode |= FMODE_NOWAIT;
848 return dquot_file_open(inode, filp);
849}
850
851/*
852 * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
853 * by calling generic_file_llseek_size() with the appropriate maxbytes
854 * value for each.
855 */
856loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
857{
858 struct inode *inode = file->f_mapping->host;
859 loff_t maxbytes;
860
861 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
862 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
863 else
864 maxbytes = inode->i_sb->s_maxbytes;
865
866 switch (whence) {
867 default:
868 return generic_file_llseek_size(file, offset, whence,
869 maxbytes, i_size_read(inode));
870 case SEEK_HOLE:
871 inode_lock_shared(inode);
872 offset = iomap_seek_hole(inode, offset,
873 &ext4_iomap_report_ops);
874 inode_unlock_shared(inode);
875 break;
876 case SEEK_DATA:
877 inode_lock_shared(inode);
878 offset = iomap_seek_data(inode, offset,
879 &ext4_iomap_report_ops);
880 inode_unlock_shared(inode);
881 break;
882 }
883
884 if (offset < 0)
885 return offset;
886 return vfs_setpos(file, offset, maxbytes);
887}
888
889const struct file_operations ext4_file_operations = {
890 .llseek = ext4_llseek,
891 .read_iter = ext4_file_read_iter,
892 .write_iter = ext4_file_write_iter,
893 .iopoll = iomap_dio_iopoll,
894 .unlocked_ioctl = ext4_ioctl,
895#ifdef CONFIG_COMPAT
896 .compat_ioctl = ext4_compat_ioctl,
897#endif
898 .mmap = ext4_file_mmap,
899 .mmap_supported_flags = MAP_SYNC,
900 .open = ext4_file_open,
901 .release = ext4_release_file,
902 .fsync = ext4_sync_file,
903 .get_unmapped_area = thp_get_unmapped_area,
904 .splice_read = generic_file_splice_read,
905 .splice_write = iter_file_splice_write,
906 .fallocate = ext4_fallocate,
907};
908
909const struct inode_operations ext4_file_inode_operations = {
910 .setattr = ext4_setattr,
911 .getattr = ext4_file_getattr,
912 .listxattr = ext4_listxattr,
913 .get_acl = ext4_get_acl,
914 .set_acl = ext4_set_acl,
915 .fiemap = ext4_fiemap,
916};
917