Line data Source code
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 0 : static bool ext4_dio_supported(struct inode *inode)
40 : {
41 0 : if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode))
42 : return false;
43 0 : if (fsverity_active(inode))
44 : return false;
45 0 : if (ext4_should_journal_data(inode))
46 : return false;
47 0 : if (ext4_has_inline_data(inode))
48 0 : return false;
49 : return true;
50 : }
51 :
52 0 : static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
53 : {
54 0 : ssize_t ret;
55 0 : struct inode *inode = file_inode(iocb->ki_filp);
56 :
57 0 : if (iocb->ki_flags & IOCB_NOWAIT) {
58 0 : if (!inode_trylock_shared(inode))
59 : return -EAGAIN;
60 : } else {
61 0 : inode_lock_shared(inode);
62 : }
63 :
64 0 : if (!ext4_dio_supported(inode)) {
65 0 : 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 0 : iocb->ki_flags &= ~IOCB_DIRECT;
74 0 : return generic_file_read_iter(iocb, to);
75 : }
76 :
77 0 : ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0);
78 0 : inode_unlock_shared(inode);
79 :
80 0 : file_accessed(iocb->ki_filp);
81 0 : 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 15594 : static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
114 : {
115 15594 : struct inode *inode = file_inode(iocb->ki_filp);
116 :
117 15594 : if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
118 : return -EIO;
119 :
120 15594 : 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 15594 : if (iocb->ki_flags & IOCB_DIRECT)
128 0 : return ext4_dio_read_iter(iocb, to);
129 :
130 15594 : 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 11005 : static int ext4_release_file(struct inode *inode, struct file *filp)
139 : {
140 11005 : if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
141 2 : ext4_alloc_da_blocks(inode);
142 2 : 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 11005 : if ((filp->f_mode & FMODE_WRITE) &&
146 520 : (atomic_read(&inode->i_writecount) == 1) &&
147 520 : !EXT4_I(inode)->i_reserved_data_blocks) {
148 107 : down_write(&EXT4_I(inode)->i_data_sem);
149 107 : ext4_discard_preallocations(inode, 0);
150 107 : up_write(&EXT4_I(inode)->i_data_sem);
151 : }
152 22010 : if (is_dx(inode) && filp->private_data)
153 0 : ext4_htree_free_dir_info(filp->private_data);
154 :
155 11005 : 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 0 : ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
169 : {
170 0 : struct super_block *sb = inode->i_sb;
171 0 : unsigned long blockmask = sb->s_blocksize - 1;
172 :
173 0 : if ((pos | iov_iter_alignment(from)) & blockmask)
174 0 : return true;
175 :
176 : return false;
177 : }
178 :
179 : static bool
180 0 : ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
181 : {
182 0 : if (offset + len > i_size_read(inode) ||
183 0 : offset + len > EXT4_I(inode)->i_disksize)
184 0 : return true;
185 : return false;
186 : }
187 :
188 : /* Is IO overwriting allocated and initialized blocks? */
189 0 : static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
190 : {
191 0 : struct ext4_map_blocks map;
192 0 : unsigned int blkbits = inode->i_blkbits;
193 0 : int err, blklen;
194 :
195 0 : if (pos + len > i_size_read(inode))
196 : return false;
197 :
198 0 : map.m_lblk = pos >> blkbits;
199 0 : map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
200 0 : blklen = map.m_len;
201 :
202 0 : 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 0 : return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
209 : }
210 :
211 1535 : static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
212 : struct iov_iter *from)
213 : {
214 1535 : struct inode *inode = file_inode(iocb->ki_filp);
215 1535 : ssize_t ret;
216 :
217 1535 : if (unlikely(IS_IMMUTABLE(inode)))
218 : return -EPERM;
219 :
220 1535 : ret = generic_write_checks(iocb, from);
221 1535 : 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 1535 : if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
229 0 : struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
230 :
231 0 : if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
232 : return -EFBIG;
233 0 : iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
234 : }
235 :
236 1535 : return iov_iter_count(from);
237 : }
238 :
239 1535 : static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
240 : {
241 1535 : ssize_t ret, count;
242 :
243 1535 : count = ext4_generic_write_checks(iocb, from);
244 1535 : if (count <= 0)
245 : return count;
246 :
247 1535 : ret = file_modified(iocb->ki_filp);
248 1535 : if (ret)
249 0 : return ret;
250 : return count;
251 : }
252 :
253 1535 : static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
254 : struct iov_iter *from)
255 : {
256 1535 : ssize_t ret;
257 1535 : struct inode *inode = file_inode(iocb->ki_filp);
258 :
259 1535 : if (iocb->ki_flags & IOCB_NOWAIT)
260 : return -EOPNOTSUPP;
261 :
262 1535 : ext4_fc_start_update(inode);
263 1535 : inode_lock(inode);
264 1535 : ret = ext4_write_checks(iocb, from);
265 1535 : if (ret <= 0)
266 0 : goto out;
267 :
268 1535 : current->backing_dev_info = inode_to_bdi(inode);
269 1535 : ret = generic_perform_write(iocb->ki_filp, from, iocb->ki_pos);
270 1535 : current->backing_dev_info = NULL;
271 :
272 1535 : out:
273 1535 : inode_unlock(inode);
274 1535 : ext4_fc_stop_update(inode);
275 1535 : if (likely(ret > 0)) {
276 1535 : iocb->ki_pos += ret;
277 1535 : ret = generic_write_sync(iocb, ret);
278 : }
279 :
280 : return ret;
281 : }
282 :
283 0 : static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
284 : ssize_t written, size_t count)
285 : {
286 0 : handle_t *handle;
287 0 : bool truncate = false;
288 0 : u8 blkbits = inode->i_blkbits;
289 0 : ext4_lblk_t written_blk, end_blk;
290 0 : 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 0 : WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
301 0 : 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 0 : if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
308 0 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
309 :
310 0 : if (IS_ERR(handle)) {
311 0 : ext4_orphan_del(NULL, inode);
312 0 : return PTR_ERR(handle);
313 : }
314 :
315 0 : ext4_orphan_del(handle, inode);
316 0 : ext4_journal_stop(handle);
317 : }
318 :
319 0 : return written;
320 : }
321 :
322 0 : if (written < 0)
323 0 : goto truncate;
324 :
325 0 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
326 0 : if (IS_ERR(handle)) {
327 0 : written = PTR_ERR(handle);
328 0 : goto truncate;
329 : }
330 :
331 0 : if (ext4_update_inode_size(inode, offset + written)) {
332 0 : ret = ext4_mark_inode_dirty(handle, inode);
333 0 : if (unlikely(ret)) {
334 0 : written = ret;
335 0 : ext4_journal_stop(handle);
336 0 : goto truncate;
337 : }
338 : }
339 :
340 : /*
341 : * We may need to truncate allocated but not written blocks beyond EOF.
342 : */
343 0 : written_blk = ALIGN(offset + written, 1 << blkbits);
344 0 : end_blk = ALIGN(offset + count, 1 << blkbits);
345 0 : 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 0 : if (!truncate && inode->i_nlink)
353 0 : ext4_orphan_del(handle, inode);
354 0 : ext4_journal_stop(handle);
355 :
356 0 : if (truncate) {
357 0 : truncate:
358 0 : 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 0 : if (inode->i_nlink)
365 0 : ext4_orphan_del(NULL, inode);
366 : }
367 :
368 : return written;
369 : }
370 :
371 0 : static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
372 : int error, unsigned int flags)
373 : {
374 0 : loff_t offset = iocb->ki_pos;
375 0 : struct inode *inode = file_inode(iocb->ki_filp);
376 :
377 0 : if (error)
378 : return error;
379 :
380 0 : if (size && flags & IOMAP_DIO_UNWRITTEN)
381 0 : return ext4_convert_unwritten_extents(NULL, inode,
382 : offset, size);
383 :
384 : return 0;
385 : }
386 :
387 : static const struct iomap_dio_ops ext4_dio_write_ops = {
388 : .end_io = ext4_dio_write_end_io,
389 : };
390 :
391 : /*
392 : * The intention here is to start with shared lock acquired then see if any
393 : * condition requires an exclusive inode lock. If yes, then we restart the
394 : * whole operation by releasing the shared lock and acquiring exclusive lock.
395 : *
396 : * - For unaligned_io we never take shared lock as it may cause data corruption
397 : * when two unaligned IO tries to modify the same block e.g. while zeroing.
398 : *
399 : * - For extending writes case we don't take the shared lock, since it requires
400 : * updating inode i_disksize and/or orphan handling with exclusive lock.
401 : *
402 : * - shared locking will only be true mostly with overwrites. Otherwise we will
403 : * switch to exclusive i_rwsem lock.
404 : */
405 0 : static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
406 : bool *ilock_shared, bool *extend)
407 : {
408 0 : struct file *file = iocb->ki_filp;
409 0 : struct inode *inode = file_inode(file);
410 0 : loff_t offset;
411 0 : size_t count;
412 0 : ssize_t ret;
413 :
414 0 : restart:
415 0 : ret = ext4_generic_write_checks(iocb, from);
416 0 : if (ret <= 0)
417 0 : goto out;
418 :
419 0 : offset = iocb->ki_pos;
420 0 : count = ret;
421 0 : if (ext4_extending_io(inode, offset, count))
422 0 : *extend = true;
423 : /*
424 : * Determine whether the IO operation will overwrite allocated
425 : * and initialized blocks.
426 : * We need exclusive i_rwsem for changing security info
427 : * in file_modified().
428 : */
429 0 : if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
430 0 : !ext4_overwrite_io(inode, offset, count))) {
431 0 : if (iocb->ki_flags & IOCB_NOWAIT) {
432 0 : ret = -EAGAIN;
433 0 : goto out;
434 : }
435 0 : inode_unlock_shared(inode);
436 0 : *ilock_shared = false;
437 0 : inode_lock(inode);
438 0 : goto restart;
439 : }
440 :
441 0 : ret = file_modified(file);
442 0 : if (ret < 0)
443 0 : goto out;
444 :
445 : return count;
446 0 : out:
447 0 : if (*ilock_shared)
448 0 : inode_unlock_shared(inode);
449 : else
450 0 : inode_unlock(inode);
451 : return ret;
452 : }
453 :
454 0 : static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
455 : {
456 0 : ssize_t ret;
457 0 : handle_t *handle;
458 0 : struct inode *inode = file_inode(iocb->ki_filp);
459 0 : loff_t offset = iocb->ki_pos;
460 0 : size_t count = iov_iter_count(from);
461 0 : const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
462 0 : bool extend = false, unaligned_io = false;
463 0 : bool ilock_shared = true;
464 :
465 : /*
466 : * We initially start with shared inode lock unless it is
467 : * unaligned IO which needs exclusive lock anyways.
468 : */
469 0 : if (ext4_unaligned_io(inode, from, offset)) {
470 0 : unaligned_io = true;
471 0 : ilock_shared = false;
472 : }
473 : /*
474 : * Quick check here without any i_rwsem lock to see if it is extending
475 : * IO. A more reliable check is done in ext4_dio_write_checks() with
476 : * proper locking in place.
477 : */
478 0 : if (offset + count > i_size_read(inode))
479 0 : ilock_shared = false;
480 :
481 0 : if (iocb->ki_flags & IOCB_NOWAIT) {
482 0 : if (ilock_shared) {
483 0 : if (!inode_trylock_shared(inode))
484 : return -EAGAIN;
485 : } else {
486 0 : if (!inode_trylock(inode))
487 : return -EAGAIN;
488 : }
489 : } else {
490 0 : if (ilock_shared)
491 0 : inode_lock_shared(inode);
492 : else
493 0 : inode_lock(inode);
494 : }
495 :
496 : /* Fallback to buffered I/O if the inode does not support direct I/O. */
497 0 : if (!ext4_dio_supported(inode)) {
498 0 : if (ilock_shared)
499 0 : inode_unlock_shared(inode);
500 : else
501 0 : inode_unlock(inode);
502 0 : return ext4_buffered_write_iter(iocb, from);
503 : }
504 :
505 0 : ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
506 0 : if (ret <= 0)
507 : return ret;
508 :
509 : /* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
510 0 : if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
511 0 : ret = -EAGAIN;
512 0 : goto out;
513 : }
514 :
515 0 : offset = iocb->ki_pos;
516 0 : count = ret;
517 :
518 : /*
519 : * Unaligned direct IO must be serialized among each other as zeroing
520 : * of partial blocks of two competing unaligned IOs can result in data
521 : * corruption.
522 : *
523 : * So we make sure we don't allow any unaligned IO in flight.
524 : * For IOs where we need not wait (like unaligned non-AIO DIO),
525 : * below inode_dio_wait() may anyway become a no-op, since we start
526 : * with exclusive lock.
527 : */
528 0 : if (unaligned_io)
529 0 : inode_dio_wait(inode);
530 :
531 0 : if (extend) {
532 0 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
533 0 : if (IS_ERR(handle)) {
534 0 : ret = PTR_ERR(handle);
535 0 : goto out;
536 : }
537 :
538 0 : ext4_fc_start_update(inode);
539 0 : ret = ext4_orphan_add(handle, inode);
540 0 : ext4_fc_stop_update(inode);
541 0 : if (ret) {
542 0 : ext4_journal_stop(handle);
543 0 : goto out;
544 : }
545 :
546 0 : ext4_journal_stop(handle);
547 : }
548 :
549 0 : if (ilock_shared)
550 0 : iomap_ops = &ext4_iomap_overwrite_ops;
551 0 : ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
552 0 : (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0);
553 0 : if (ret == -ENOTBLK)
554 0 : ret = 0;
555 :
556 0 : if (extend)
557 0 : ret = ext4_handle_inode_extension(inode, offset, ret, count);
558 :
559 0 : out:
560 0 : if (ilock_shared)
561 0 : inode_unlock_shared(inode);
562 : else
563 0 : inode_unlock(inode);
564 :
565 0 : if (ret >= 0 && iov_iter_count(from)) {
566 0 : ssize_t err;
567 0 : loff_t endbyte;
568 :
569 0 : offset = iocb->ki_pos;
570 0 : err = ext4_buffered_write_iter(iocb, from);
571 0 : if (err < 0)
572 : return err;
573 :
574 : /*
575 : * We need to ensure that the pages within the page cache for
576 : * the range covered by this I/O are written to disk and
577 : * invalidated. This is in attempt to preserve the expected
578 : * direct I/O semantics in the case we fallback to buffered I/O
579 : * to complete off the I/O request.
580 : */
581 0 : ret += err;
582 0 : endbyte = offset + err - 1;
583 0 : err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
584 : offset, endbyte);
585 0 : if (!err)
586 0 : invalidate_mapping_pages(iocb->ki_filp->f_mapping,
587 0 : offset >> PAGE_SHIFT,
588 0 : endbyte >> PAGE_SHIFT);
589 : }
590 :
591 : return ret;
592 : }
593 :
594 : #ifdef CONFIG_FS_DAX
595 : static ssize_t
596 : ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
597 : {
598 : ssize_t ret;
599 : size_t count;
600 : loff_t offset;
601 : handle_t *handle;
602 : bool extend = false;
603 : struct inode *inode = file_inode(iocb->ki_filp);
604 :
605 : if (iocb->ki_flags & IOCB_NOWAIT) {
606 : if (!inode_trylock(inode))
607 : return -EAGAIN;
608 : } else {
609 : inode_lock(inode);
610 : }
611 :
612 : ret = ext4_write_checks(iocb, from);
613 : if (ret <= 0)
614 : goto out;
615 :
616 : offset = iocb->ki_pos;
617 : count = iov_iter_count(from);
618 :
619 : if (offset + count > EXT4_I(inode)->i_disksize) {
620 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
621 : if (IS_ERR(handle)) {
622 : ret = PTR_ERR(handle);
623 : goto out;
624 : }
625 :
626 : ret = ext4_orphan_add(handle, inode);
627 : if (ret) {
628 : ext4_journal_stop(handle);
629 : goto out;
630 : }
631 :
632 : extend = true;
633 : ext4_journal_stop(handle);
634 : }
635 :
636 : ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
637 :
638 : if (extend)
639 : ret = ext4_handle_inode_extension(inode, offset, ret, count);
640 : out:
641 : inode_unlock(inode);
642 : if (ret > 0)
643 : ret = generic_write_sync(iocb, ret);
644 : return ret;
645 : }
646 : #endif
647 :
648 : static ssize_t
649 1535 : ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
650 : {
651 1535 : struct inode *inode = file_inode(iocb->ki_filp);
652 :
653 1535 : if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
654 : return -EIO;
655 :
656 : #ifdef CONFIG_FS_DAX
657 : if (IS_DAX(inode))
658 : return ext4_dax_write_iter(iocb, from);
659 : #endif
660 1535 : if (iocb->ki_flags & IOCB_DIRECT)
661 0 : return ext4_dio_write_iter(iocb, from);
662 : else
663 1535 : return ext4_buffered_write_iter(iocb, from);
664 : }
665 :
666 : #ifdef CONFIG_FS_DAX
667 : static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
668 : enum page_entry_size pe_size)
669 : {
670 : int error = 0;
671 : vm_fault_t result;
672 : int retries = 0;
673 : handle_t *handle = NULL;
674 : struct inode *inode = file_inode(vmf->vma->vm_file);
675 : struct super_block *sb = inode->i_sb;
676 :
677 : /*
678 : * We have to distinguish real writes from writes which will result in a
679 : * COW page; COW writes should *not* poke the journal (the file will not
680 : * be changed). Doing so would cause unintended failures when mounted
681 : * read-only.
682 : *
683 : * We check for VM_SHARED rather than vmf->cow_page since the latter is
684 : * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
685 : * other sizes, dax_iomap_fault will handle splitting / fallback so that
686 : * we eventually come back with a COW page.
687 : */
688 : bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
689 : (vmf->vma->vm_flags & VM_SHARED);
690 : pfn_t pfn;
691 :
692 : if (write) {
693 : sb_start_pagefault(sb);
694 : file_update_time(vmf->vma->vm_file);
695 : down_read(&EXT4_I(inode)->i_mmap_sem);
696 : retry:
697 : handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
698 : EXT4_DATA_TRANS_BLOCKS(sb));
699 : if (IS_ERR(handle)) {
700 : up_read(&EXT4_I(inode)->i_mmap_sem);
701 : sb_end_pagefault(sb);
702 : return VM_FAULT_SIGBUS;
703 : }
704 : } else {
705 : down_read(&EXT4_I(inode)->i_mmap_sem);
706 : }
707 : result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
708 : if (write) {
709 : ext4_journal_stop(handle);
710 :
711 : if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
712 : ext4_should_retry_alloc(sb, &retries))
713 : goto retry;
714 : /* Handling synchronous page fault? */
715 : if (result & VM_FAULT_NEEDDSYNC)
716 : result = dax_finish_sync_fault(vmf, pe_size, pfn);
717 : up_read(&EXT4_I(inode)->i_mmap_sem);
718 : sb_end_pagefault(sb);
719 : } else {
720 : up_read(&EXT4_I(inode)->i_mmap_sem);
721 : }
722 :
723 : return result;
724 : }
725 :
726 : static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
727 : {
728 : return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
729 : }
730 :
731 : static const struct vm_operations_struct ext4_dax_vm_ops = {
732 : .fault = ext4_dax_fault,
733 : .huge_fault = ext4_dax_huge_fault,
734 : .page_mkwrite = ext4_dax_fault,
735 : .pfn_mkwrite = ext4_dax_fault,
736 : };
737 : #else
738 : #define ext4_dax_vm_ops ext4_file_vm_ops
739 : #endif
740 :
741 : static const struct vm_operations_struct ext4_file_vm_ops = {
742 : .fault = ext4_filemap_fault,
743 : .map_pages = filemap_map_pages,
744 : .page_mkwrite = ext4_page_mkwrite,
745 : };
746 :
747 26782 : static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
748 : {
749 26782 : struct inode *inode = file->f_mapping->host;
750 26782 : struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
751 26782 : struct dax_device *dax_dev = sbi->s_daxdev;
752 :
753 26782 : if (unlikely(ext4_forced_shutdown(sbi)))
754 : return -EIO;
755 :
756 : /*
757 : * We don't support synchronous mappings for non-DAX files and
758 : * for DAX files if underneath dax_device is not synchronous.
759 : */
760 26782 : if (!daxdev_mapping_supported(vma, dax_dev))
761 : return -EOPNOTSUPP;
762 :
763 26782 : file_accessed(file);
764 26782 : if (IS_DAX(file_inode(file))) {
765 : vma->vm_ops = &ext4_dax_vm_ops;
766 : vma->vm_flags |= VM_HUGEPAGE;
767 : } else {
768 26782 : vma->vm_ops = &ext4_file_vm_ops;
769 : }
770 26782 : return 0;
771 : }
772 :
773 11413 : static int ext4_sample_last_mounted(struct super_block *sb,
774 : struct vfsmount *mnt)
775 : {
776 11413 : struct ext4_sb_info *sbi = EXT4_SB(sb);
777 11413 : struct path path;
778 11413 : char buf[64], *cp;
779 11413 : handle_t *handle;
780 11413 : int err;
781 :
782 11413 : if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
783 : return 0;
784 :
785 905 : if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
786 903 : return 0;
787 :
788 1 : ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
789 : /*
790 : * Sample where the filesystem has been mounted and
791 : * store it in the superblock for sysadmin convenience
792 : * when trying to sort through large numbers of block
793 : * devices or filesystem images.
794 : */
795 1 : memset(buf, 0, sizeof(buf));
796 1 : path.mnt = mnt;
797 1 : path.dentry = mnt->mnt_root;
798 1 : cp = d_path(&path, buf, sizeof(buf));
799 1 : err = 0;
800 1 : if (IS_ERR(cp))
801 0 : goto out;
802 :
803 1 : handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
804 1 : err = PTR_ERR(handle);
805 1 : if (IS_ERR(handle))
806 0 : goto out;
807 1 : BUFFER_TRACE(sbi->s_sbh, "get_write_access");
808 1 : err = ext4_journal_get_write_access(handle, sbi->s_sbh);
809 1 : if (err)
810 0 : goto out_journal;
811 1 : lock_buffer(sbi->s_sbh);
812 1 : strncpy(sbi->s_es->s_last_mounted, cp,
813 : sizeof(sbi->s_es->s_last_mounted));
814 1 : ext4_superblock_csum_set(sb);
815 1 : unlock_buffer(sbi->s_sbh);
816 1 : ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
817 1 : out_journal:
818 1 : ext4_journal_stop(handle);
819 1 : out:
820 1 : sb_end_intwrite(sb);
821 1 : return err;
822 : }
823 :
824 11412 : static int ext4_file_open(struct inode *inode, struct file *filp)
825 : {
826 11412 : int ret;
827 :
828 11412 : if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
829 : return -EIO;
830 :
831 11413 : ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
832 11413 : if (ret)
833 : return ret;
834 :
835 11413 : ret = fscrypt_file_open(inode, filp);
836 11413 : if (ret)
837 : return ret;
838 :
839 11413 : ret = fsverity_file_open(inode, filp);
840 11413 : if (ret)
841 : return ret;
842 :
843 : /*
844 : * Set up the jbd2_inode if we are opening the inode for
845 : * writing and the journal is present
846 : */
847 11413 : if (filp->f_mode & FMODE_WRITE) {
848 527 : ret = ext4_inode_attach_jinode(inode);
849 527 : if (ret < 0)
850 : return ret;
851 : }
852 :
853 11413 : filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
854 11413 : return dquot_file_open(inode, filp);
855 : }
856 :
857 : /*
858 : * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
859 : * by calling generic_file_llseek_size() with the appropriate maxbytes
860 : * value for each.
861 : */
862 1869 : loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
863 : {
864 1869 : struct inode *inode = file->f_mapping->host;
865 1869 : loff_t maxbytes;
866 :
867 1869 : if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
868 0 : maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
869 : else
870 1869 : maxbytes = inode->i_sb->s_maxbytes;
871 :
872 1869 : switch (whence) {
873 : default:
874 1869 : return generic_file_llseek_size(file, offset, whence,
875 : maxbytes, i_size_read(inode));
876 : case SEEK_HOLE:
877 0 : inode_lock_shared(inode);
878 0 : offset = iomap_seek_hole(inode, offset,
879 : &ext4_iomap_report_ops);
880 0 : inode_unlock_shared(inode);
881 : break;
882 : case SEEK_DATA:
883 0 : inode_lock_shared(inode);
884 0 : offset = iomap_seek_data(inode, offset,
885 : &ext4_iomap_report_ops);
886 0 : inode_unlock_shared(inode);
887 : break;
888 : }
889 :
890 0 : if (offset < 0)
891 : return offset;
892 0 : return vfs_setpos(file, offset, maxbytes);
893 : }
894 :
895 : const struct file_operations ext4_file_operations = {
896 : .llseek = ext4_llseek,
897 : .read_iter = ext4_file_read_iter,
898 : .write_iter = ext4_file_write_iter,
899 : .iopoll = iomap_dio_iopoll,
900 : .unlocked_ioctl = ext4_ioctl,
901 : #ifdef CONFIG_COMPAT
902 : .compat_ioctl = ext4_compat_ioctl,
903 : #endif
904 : .mmap = ext4_file_mmap,
905 : .mmap_supported_flags = MAP_SYNC,
906 : .open = ext4_file_open,
907 : .release = ext4_release_file,
908 : .fsync = ext4_sync_file,
909 : .get_unmapped_area = thp_get_unmapped_area,
910 : .splice_read = generic_file_splice_read,
911 : .splice_write = iter_file_splice_write,
912 : .fallocate = ext4_fallocate,
913 : };
914 :
915 : const struct inode_operations ext4_file_inode_operations = {
916 : .setattr = ext4_setattr,
917 : .getattr = ext4_file_getattr,
918 : .listxattr = ext4_listxattr,
919 : .get_acl = ext4_get_acl,
920 : .set_acl = ext4_set_acl,
921 : .fiemap = ext4_fiemap,
922 : };
923 :
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