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 : /*
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 : */
55 0 : static bool ext4_should_use_dio(struct kiocb *iocb, struct iov_iter *iter)
56 : {
57 0 : struct inode *inode = file_inode(iocb->ki_filp);
58 0 : u32 dio_align = ext4_dio_alignment(inode);
59 :
60 0 : if (dio_align == 0)
61 : return false;
62 :
63 0 : if (dio_align == 1)
64 : return true;
65 :
66 0 : return IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter), dio_align);
67 : }
68 :
69 0 : static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
70 : {
71 0 : ssize_t ret;
72 0 : struct inode *inode = file_inode(iocb->ki_filp);
73 :
74 0 : if (iocb->ki_flags & IOCB_NOWAIT) {
75 0 : if (!inode_trylock_shared(inode))
76 : return -EAGAIN;
77 : } else {
78 0 : inode_lock_shared(inode);
79 : }
80 :
81 0 : if (!ext4_should_use_dio(iocb, to)) {
82 0 : 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 0 : iocb->ki_flags &= ~IOCB_DIRECT;
91 0 : return generic_file_read_iter(iocb, to);
92 : }
93 :
94 0 : ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, NULL, 0);
95 0 : inode_unlock_shared(inode);
96 :
97 0 : file_accessed(iocb->ki_filp);
98 0 : return ret;
99 : }
100 :
101 : #ifdef CONFIG_FS_DAX
102 : static 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 :
130 0 : static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
131 : {
132 0 : struct inode *inode = file_inode(iocb->ki_filp);
133 :
134 0 : if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
135 : return -EIO;
136 :
137 0 : 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 0 : if (iocb->ki_flags & IOCB_DIRECT)
145 0 : return ext4_dio_read_iter(iocb, to);
146 :
147 0 : return generic_file_read_iter(iocb, to);
148 : }
149 :
150 0 : static ssize_t ext4_file_splice_read(struct file *in, loff_t *ppos,
151 : struct pipe_inode_info *pipe,
152 : size_t len, unsigned int flags)
153 : {
154 0 : struct inode *inode = file_inode(in);
155 :
156 0 : if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
157 : return -EIO;
158 0 : return filemap_splice_read(in, ppos, pipe, len, flags);
159 : }
160 :
161 : /*
162 : * Called when an inode is released. Note that this is different
163 : * from ext4_file_open: open gets called at every open, but release
164 : * gets called only when /all/ the files are closed.
165 : */
166 0 : static int ext4_release_file(struct inode *inode, struct file *filp)
167 : {
168 0 : if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
169 0 : ext4_alloc_da_blocks(inode);
170 0 : ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
171 : }
172 : /* if we are the last writer on the inode, drop the block reservation */
173 0 : if ((filp->f_mode & FMODE_WRITE) &&
174 0 : (atomic_read(&inode->i_writecount) == 1) &&
175 0 : !EXT4_I(inode)->i_reserved_data_blocks) {
176 0 : down_write(&EXT4_I(inode)->i_data_sem);
177 0 : ext4_discard_preallocations(inode, 0);
178 0 : up_write(&EXT4_I(inode)->i_data_sem);
179 : }
180 0 : if (is_dx(inode) && filp->private_data)
181 0 : ext4_htree_free_dir_info(filp->private_data);
182 :
183 0 : return 0;
184 : }
185 :
186 : /*
187 : * This tests whether the IO in question is block-aligned or not.
188 : * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
189 : * are converted to written only after the IO is complete. Until they are
190 : * mapped, these blocks appear as holes, so dio_zero_block() will assume that
191 : * it needs to zero out portions of the start and/or end block. If 2 AIO
192 : * threads are at work on the same unwritten block, they must be synchronized
193 : * or one thread will zero the other's data, causing corruption.
194 : */
195 : static bool
196 0 : ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
197 : {
198 0 : struct super_block *sb = inode->i_sb;
199 0 : unsigned long blockmask = sb->s_blocksize - 1;
200 :
201 0 : if ((pos | iov_iter_alignment(from)) & blockmask)
202 0 : return true;
203 :
204 : return false;
205 : }
206 :
207 : static bool
208 : ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
209 : {
210 0 : if (offset + len > i_size_read(inode) ||
211 0 : offset + len > EXT4_I(inode)->i_disksize)
212 0 : return true;
213 : return false;
214 : }
215 :
216 : /* Is IO overwriting allocated or initialized blocks? */
217 0 : static bool ext4_overwrite_io(struct inode *inode,
218 : loff_t pos, loff_t len, bool *unwritten)
219 : {
220 0 : struct ext4_map_blocks map;
221 0 : unsigned int blkbits = inode->i_blkbits;
222 0 : int err, blklen;
223 :
224 0 : if (pos + len > i_size_read(inode))
225 : return false;
226 :
227 0 : map.m_lblk = pos >> blkbits;
228 0 : map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
229 0 : blklen = map.m_len;
230 :
231 0 : err = ext4_map_blocks(NULL, inode, &map, 0);
232 0 : if (err != blklen)
233 : return false;
234 : /*
235 : * 'err==len' means that all of the blocks have been preallocated,
236 : * regardless of whether they have been initialized or not. We need to
237 : * check m_flags to distinguish the unwritten extents.
238 : */
239 0 : *unwritten = !(map.m_flags & EXT4_MAP_MAPPED);
240 0 : return true;
241 : }
242 :
243 0 : static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
244 : struct iov_iter *from)
245 : {
246 0 : struct inode *inode = file_inode(iocb->ki_filp);
247 0 : ssize_t ret;
248 :
249 0 : if (unlikely(IS_IMMUTABLE(inode)))
250 : return -EPERM;
251 :
252 0 : ret = generic_write_checks(iocb, from);
253 0 : if (ret <= 0)
254 : return ret;
255 :
256 : /*
257 : * If we have encountered a bitmap-format file, the size limit
258 : * is smaller than s_maxbytes, which is for extent-mapped files.
259 : */
260 0 : if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
261 0 : struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
262 :
263 0 : if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
264 : return -EFBIG;
265 0 : iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
266 : }
267 :
268 0 : return iov_iter_count(from);
269 : }
270 :
271 0 : static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
272 : {
273 0 : ssize_t ret, count;
274 :
275 0 : count = ext4_generic_write_checks(iocb, from);
276 0 : if (count <= 0)
277 : return count;
278 :
279 0 : ret = file_modified(iocb->ki_filp);
280 0 : if (ret)
281 0 : return ret;
282 : return count;
283 : }
284 :
285 0 : static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
286 : struct iov_iter *from)
287 : {
288 0 : ssize_t ret;
289 0 : struct inode *inode = file_inode(iocb->ki_filp);
290 :
291 0 : if (iocb->ki_flags & IOCB_NOWAIT)
292 : return -EOPNOTSUPP;
293 :
294 0 : inode_lock(inode);
295 0 : ret = ext4_write_checks(iocb, from);
296 0 : if (ret <= 0)
297 0 : goto out;
298 :
299 0 : ret = generic_perform_write(iocb, from);
300 :
301 0 : out:
302 0 : inode_unlock(inode);
303 0 : if (unlikely(ret <= 0))
304 : return ret;
305 0 : return generic_write_sync(iocb, ret);
306 : }
307 :
308 0 : static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
309 : ssize_t written, size_t count)
310 : {
311 0 : handle_t *handle;
312 0 : bool truncate = false;
313 0 : u8 blkbits = inode->i_blkbits;
314 0 : ext4_lblk_t written_blk, end_blk;
315 0 : int ret;
316 :
317 : /*
318 : * Note that EXT4_I(inode)->i_disksize can get extended up to
319 : * inode->i_size while the I/O was running due to writeback of delalloc
320 : * blocks. But, the code in ext4_iomap_alloc() is careful to use
321 : * zeroed/unwritten extents if this is possible; thus we won't leave
322 : * uninitialized blocks in a file even if we didn't succeed in writing
323 : * as much as we intended.
324 : */
325 0 : WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
326 0 : if (offset + count <= EXT4_I(inode)->i_disksize) {
327 : /*
328 : * We need to ensure that the inode is removed from the orphan
329 : * list if it has been added prematurely, due to writeback of
330 : * delalloc blocks.
331 : */
332 0 : if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
333 0 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
334 :
335 0 : if (IS_ERR(handle)) {
336 0 : ext4_orphan_del(NULL, inode);
337 0 : return PTR_ERR(handle);
338 : }
339 :
340 0 : ext4_orphan_del(handle, inode);
341 0 : ext4_journal_stop(handle);
342 : }
343 :
344 0 : return written;
345 : }
346 :
347 0 : if (written < 0)
348 0 : goto truncate;
349 :
350 0 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
351 0 : if (IS_ERR(handle)) {
352 0 : written = PTR_ERR(handle);
353 0 : goto truncate;
354 : }
355 :
356 0 : if (ext4_update_inode_size(inode, offset + written)) {
357 0 : ret = ext4_mark_inode_dirty(handle, inode);
358 0 : if (unlikely(ret)) {
359 0 : written = ret;
360 0 : ext4_journal_stop(handle);
361 0 : goto truncate;
362 : }
363 : }
364 :
365 : /*
366 : * We may need to truncate allocated but not written blocks beyond EOF.
367 : */
368 0 : written_blk = ALIGN(offset + written, 1 << blkbits);
369 0 : end_blk = ALIGN(offset + count, 1 << blkbits);
370 0 : if (written_blk < end_blk && ext4_can_truncate(inode))
371 : truncate = true;
372 :
373 : /*
374 : * Remove the inode from the orphan list if it has been extended and
375 : * everything went OK.
376 : */
377 0 : if (!truncate && inode->i_nlink)
378 0 : ext4_orphan_del(handle, inode);
379 0 : ext4_journal_stop(handle);
380 :
381 0 : if (truncate) {
382 0 : truncate:
383 0 : ext4_truncate_failed_write(inode);
384 : /*
385 : * If the truncate operation failed early, then the inode may
386 : * still be on the orphan list. In that case, we need to try
387 : * remove the inode from the in-memory linked list.
388 : */
389 0 : if (inode->i_nlink)
390 0 : ext4_orphan_del(NULL, inode);
391 : }
392 :
393 : return written;
394 : }
395 :
396 0 : static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
397 : int error, unsigned int flags)
398 : {
399 0 : loff_t pos = iocb->ki_pos;
400 0 : struct inode *inode = file_inode(iocb->ki_filp);
401 :
402 0 : if (error)
403 : return error;
404 :
405 0 : if (size && flags & IOMAP_DIO_UNWRITTEN) {
406 0 : error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
407 0 : if (error < 0)
408 : return error;
409 : }
410 : /*
411 : * If we are extending the file, we have to update i_size here before
412 : * page cache gets invalidated in iomap_dio_rw(). Otherwise racing
413 : * buffered reads could zero out too much from page cache pages. Update
414 : * of on-disk size will happen later in ext4_dio_write_iter() where
415 : * we have enough information to also perform orphan list handling etc.
416 : * Note that we perform all extending writes synchronously under
417 : * i_rwsem held exclusively so i_size update is safe here in that case.
418 : * If the write was not extending, we cannot see pos > i_size here
419 : * because operations reducing i_size like truncate wait for all
420 : * outstanding DIO before updating i_size.
421 : */
422 0 : pos += size;
423 0 : if (pos > i_size_read(inode))
424 0 : i_size_write(inode, pos);
425 :
426 : return 0;
427 : }
428 :
429 : static const struct iomap_dio_ops ext4_dio_write_ops = {
430 : .end_io = ext4_dio_write_end_io,
431 : };
432 :
433 : /*
434 : * The intention here is to start with shared lock acquired then see if any
435 : * condition requires an exclusive inode lock. If yes, then we restart the
436 : * whole operation by releasing the shared lock and acquiring exclusive lock.
437 : *
438 : * - For unaligned_io we never take shared lock as it may cause data corruption
439 : * when two unaligned IO tries to modify the same block e.g. while zeroing.
440 : *
441 : * - For extending writes case we don't take the shared lock, since it requires
442 : * updating inode i_disksize and/or orphan handling with exclusive lock.
443 : *
444 : * - shared locking will only be true mostly with overwrites, including
445 : * initialized blocks and unwritten blocks. For overwrite unwritten blocks
446 : * we protect splitting extents by i_data_sem in ext4_inode_info, so we can
447 : * also release exclusive i_rwsem lock.
448 : *
449 : * - Otherwise we will switch to exclusive i_rwsem lock.
450 : */
451 0 : static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
452 : bool *ilock_shared, bool *extend,
453 : bool *unwritten, int *dio_flags)
454 : {
455 0 : struct file *file = iocb->ki_filp;
456 0 : struct inode *inode = file_inode(file);
457 0 : loff_t offset;
458 0 : size_t count;
459 0 : ssize_t ret;
460 0 : bool overwrite, unaligned_io;
461 :
462 0 : restart:
463 0 : ret = ext4_generic_write_checks(iocb, from);
464 0 : if (ret <= 0)
465 0 : goto out;
466 :
467 0 : offset = iocb->ki_pos;
468 0 : count = ret;
469 :
470 0 : unaligned_io = ext4_unaligned_io(inode, from, offset);
471 0 : *extend = ext4_extending_io(inode, offset, count);
472 0 : overwrite = ext4_overwrite_io(inode, offset, count, unwritten);
473 :
474 : /*
475 : * Determine whether we need to upgrade to an exclusive lock. This is
476 : * required to change security info in file_modified(), for extending
477 : * I/O, any form of non-overwrite I/O, and unaligned I/O to unwritten
478 : * extents (as partial block zeroing may be required).
479 : */
480 0 : if (*ilock_shared &&
481 0 : ((!IS_NOSEC(inode) || *extend || !overwrite ||
482 0 : (unaligned_io && *unwritten)))) {
483 0 : if (iocb->ki_flags & IOCB_NOWAIT) {
484 0 : ret = -EAGAIN;
485 0 : goto out;
486 : }
487 0 : inode_unlock_shared(inode);
488 0 : *ilock_shared = false;
489 0 : inode_lock(inode);
490 0 : goto restart;
491 : }
492 :
493 : /*
494 : * Now that locking is settled, determine dio flags and exclusivity
495 : * requirements. Unaligned writes are allowed under shared lock so long
496 : * as they are pure overwrites. Set the iomap overwrite only flag as an
497 : * added precaution in this case. Even though this is unnecessary, we
498 : * can detect and warn on unexpected -EAGAIN if an unsafe unaligned
499 : * write is ever submitted.
500 : *
501 : * Otherwise, concurrent unaligned writes risk data corruption due to
502 : * partial block zeroing in the dio layer, and so the I/O must occur
503 : * exclusively. The inode lock is already held exclusive if the write is
504 : * non-overwrite or extending, so drain all outstanding dio and set the
505 : * force wait dio flag.
506 : */
507 0 : if (*ilock_shared && unaligned_io) {
508 0 : *dio_flags = IOMAP_DIO_OVERWRITE_ONLY;
509 0 : } else if (!*ilock_shared && (unaligned_io || *extend)) {
510 0 : if (iocb->ki_flags & IOCB_NOWAIT) {
511 0 : ret = -EAGAIN;
512 0 : goto out;
513 : }
514 0 : if (unaligned_io && (!overwrite || *unwritten))
515 0 : inode_dio_wait(inode);
516 0 : *dio_flags = IOMAP_DIO_FORCE_WAIT;
517 : }
518 :
519 0 : ret = file_modified(file);
520 0 : if (ret < 0)
521 0 : goto out;
522 :
523 : return count;
524 0 : out:
525 0 : if (*ilock_shared)
526 0 : inode_unlock_shared(inode);
527 : else
528 0 : inode_unlock(inode);
529 : return ret;
530 : }
531 :
532 0 : static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
533 : {
534 0 : ssize_t ret;
535 0 : handle_t *handle;
536 0 : struct inode *inode = file_inode(iocb->ki_filp);
537 0 : loff_t offset = iocb->ki_pos;
538 0 : size_t count = iov_iter_count(from);
539 0 : const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
540 0 : bool extend = false, unwritten = false;
541 0 : bool ilock_shared = true;
542 0 : int dio_flags = 0;
543 :
544 : /*
545 : * Quick check here without any i_rwsem lock to see if it is extending
546 : * IO. A more reliable check is done in ext4_dio_write_checks() with
547 : * proper locking in place.
548 : */
549 0 : if (offset + count > i_size_read(inode))
550 0 : ilock_shared = false;
551 :
552 0 : if (iocb->ki_flags & IOCB_NOWAIT) {
553 0 : if (ilock_shared) {
554 0 : if (!inode_trylock_shared(inode))
555 : return -EAGAIN;
556 : } else {
557 0 : if (!inode_trylock(inode))
558 : return -EAGAIN;
559 : }
560 : } else {
561 0 : if (ilock_shared)
562 0 : inode_lock_shared(inode);
563 : else
564 0 : inode_lock(inode);
565 : }
566 :
567 : /* Fallback to buffered I/O if the inode does not support direct I/O. */
568 0 : if (!ext4_should_use_dio(iocb, from)) {
569 0 : if (ilock_shared)
570 0 : inode_unlock_shared(inode);
571 : else
572 0 : inode_unlock(inode);
573 0 : return ext4_buffered_write_iter(iocb, from);
574 : }
575 :
576 0 : ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend,
577 : &unwritten, &dio_flags);
578 0 : if (ret <= 0)
579 : return ret;
580 :
581 : /*
582 : * Make sure inline data cannot be created anymore since we are going
583 : * to allocate blocks for DIO. We know the inode does not have any
584 : * inline data now because ext4_dio_supported() checked for that.
585 : */
586 0 : ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
587 :
588 0 : offset = iocb->ki_pos;
589 0 : count = ret;
590 :
591 0 : if (extend) {
592 0 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
593 0 : if (IS_ERR(handle)) {
594 0 : ret = PTR_ERR(handle);
595 0 : goto out;
596 : }
597 :
598 0 : ret = ext4_orphan_add(handle, inode);
599 0 : if (ret) {
600 0 : ext4_journal_stop(handle);
601 0 : goto out;
602 : }
603 :
604 0 : ext4_journal_stop(handle);
605 : }
606 :
607 0 : if (ilock_shared && !unwritten)
608 0 : iomap_ops = &ext4_iomap_overwrite_ops;
609 0 : ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
610 : dio_flags, NULL, 0);
611 0 : WARN_ON_ONCE(ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT));
612 0 : if (ret == -ENOTBLK)
613 0 : ret = 0;
614 :
615 0 : if (extend)
616 0 : ret = ext4_handle_inode_extension(inode, offset, ret, count);
617 :
618 0 : out:
619 0 : if (ilock_shared)
620 0 : inode_unlock_shared(inode);
621 : else
622 0 : inode_unlock(inode);
623 :
624 0 : if (ret >= 0 && iov_iter_count(from)) {
625 0 : ssize_t err;
626 0 : loff_t endbyte;
627 :
628 0 : offset = iocb->ki_pos;
629 0 : err = ext4_buffered_write_iter(iocb, from);
630 0 : if (err < 0)
631 : return err;
632 :
633 : /*
634 : * We need to ensure that the pages within the page cache for
635 : * the range covered by this I/O are written to disk and
636 : * invalidated. This is in attempt to preserve the expected
637 : * direct I/O semantics in the case we fallback to buffered I/O
638 : * to complete off the I/O request.
639 : */
640 0 : ret += err;
641 0 : endbyte = offset + err - 1;
642 0 : err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
643 : offset, endbyte);
644 0 : if (!err)
645 0 : invalidate_mapping_pages(iocb->ki_filp->f_mapping,
646 0 : offset >> PAGE_SHIFT,
647 0 : endbyte >> PAGE_SHIFT);
648 : }
649 :
650 : return ret;
651 : }
652 :
653 : #ifdef CONFIG_FS_DAX
654 : static ssize_t
655 : ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
656 : {
657 : ssize_t ret;
658 : size_t count;
659 : loff_t offset;
660 : handle_t *handle;
661 : bool extend = false;
662 : struct inode *inode = file_inode(iocb->ki_filp);
663 :
664 : if (iocb->ki_flags & IOCB_NOWAIT) {
665 : if (!inode_trylock(inode))
666 : return -EAGAIN;
667 : } else {
668 : inode_lock(inode);
669 : }
670 :
671 : ret = ext4_write_checks(iocb, from);
672 : if (ret <= 0)
673 : goto out;
674 :
675 : offset = iocb->ki_pos;
676 : count = iov_iter_count(from);
677 :
678 : if (offset + count > EXT4_I(inode)->i_disksize) {
679 : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
680 : if (IS_ERR(handle)) {
681 : ret = PTR_ERR(handle);
682 : goto out;
683 : }
684 :
685 : ret = ext4_orphan_add(handle, inode);
686 : if (ret) {
687 : ext4_journal_stop(handle);
688 : goto out;
689 : }
690 :
691 : extend = true;
692 : ext4_journal_stop(handle);
693 : }
694 :
695 : ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
696 :
697 : if (extend)
698 : ret = ext4_handle_inode_extension(inode, offset, ret, count);
699 : out:
700 : inode_unlock(inode);
701 : if (ret > 0)
702 : ret = generic_write_sync(iocb, ret);
703 : return ret;
704 : }
705 : #endif
706 :
707 : static ssize_t
708 0 : ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
709 : {
710 0 : struct inode *inode = file_inode(iocb->ki_filp);
711 :
712 0 : if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
713 : return -EIO;
714 :
715 : #ifdef CONFIG_FS_DAX
716 : if (IS_DAX(inode))
717 : return ext4_dax_write_iter(iocb, from);
718 : #endif
719 0 : if (iocb->ki_flags & IOCB_DIRECT)
720 0 : return ext4_dio_write_iter(iocb, from);
721 : else
722 0 : return ext4_buffered_write_iter(iocb, from);
723 : }
724 :
725 : #ifdef CONFIG_FS_DAX
726 : static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
727 : enum page_entry_size pe_size)
728 : {
729 : int error = 0;
730 : vm_fault_t result;
731 : int retries = 0;
732 : handle_t *handle = NULL;
733 : struct inode *inode = file_inode(vmf->vma->vm_file);
734 : struct super_block *sb = inode->i_sb;
735 :
736 : /*
737 : * We have to distinguish real writes from writes which will result in a
738 : * COW page; COW writes should *not* poke the journal (the file will not
739 : * be changed). Doing so would cause unintended failures when mounted
740 : * read-only.
741 : *
742 : * We check for VM_SHARED rather than vmf->cow_page since the latter is
743 : * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
744 : * other sizes, dax_iomap_fault will handle splitting / fallback so that
745 : * we eventually come back with a COW page.
746 : */
747 : bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
748 : (vmf->vma->vm_flags & VM_SHARED);
749 : struct address_space *mapping = vmf->vma->vm_file->f_mapping;
750 : pfn_t pfn;
751 :
752 : if (write) {
753 : sb_start_pagefault(sb);
754 : file_update_time(vmf->vma->vm_file);
755 : filemap_invalidate_lock_shared(mapping);
756 : retry:
757 : handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
758 : EXT4_DATA_TRANS_BLOCKS(sb));
759 : if (IS_ERR(handle)) {
760 : filemap_invalidate_unlock_shared(mapping);
761 : sb_end_pagefault(sb);
762 : return VM_FAULT_SIGBUS;
763 : }
764 : } else {
765 : filemap_invalidate_lock_shared(mapping);
766 : }
767 : result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
768 : if (write) {
769 : ext4_journal_stop(handle);
770 :
771 : if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
772 : ext4_should_retry_alloc(sb, &retries))
773 : goto retry;
774 : /* Handling synchronous page fault? */
775 : if (result & VM_FAULT_NEEDDSYNC)
776 : result = dax_finish_sync_fault(vmf, pe_size, pfn);
777 : filemap_invalidate_unlock_shared(mapping);
778 : sb_end_pagefault(sb);
779 : } else {
780 : filemap_invalidate_unlock_shared(mapping);
781 : }
782 :
783 : return result;
784 : }
785 :
786 : static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
787 : {
788 : return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
789 : }
790 :
791 : static const struct vm_operations_struct ext4_dax_vm_ops = {
792 : .fault = ext4_dax_fault,
793 : .huge_fault = ext4_dax_huge_fault,
794 : .page_mkwrite = ext4_dax_fault,
795 : .pfn_mkwrite = ext4_dax_fault,
796 : };
797 : #else
798 : #define ext4_dax_vm_ops ext4_file_vm_ops
799 : #endif
800 :
801 : static const struct vm_operations_struct ext4_file_vm_ops = {
802 : .fault = filemap_fault,
803 : .map_pages = filemap_map_pages,
804 : .page_mkwrite = ext4_page_mkwrite,
805 : };
806 :
807 0 : static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
808 : {
809 0 : struct inode *inode = file->f_mapping->host;
810 0 : struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
811 0 : struct dax_device *dax_dev = sbi->s_daxdev;
812 :
813 0 : if (unlikely(ext4_forced_shutdown(sbi)))
814 : return -EIO;
815 :
816 : /*
817 : * We don't support synchronous mappings for non-DAX files and
818 : * for DAX files if underneath dax_device is not synchronous.
819 : */
820 0 : if (!daxdev_mapping_supported(vma, dax_dev))
821 : return -EOPNOTSUPP;
822 :
823 0 : file_accessed(file);
824 0 : if (IS_DAX(file_inode(file))) {
825 : vma->vm_ops = &ext4_dax_vm_ops;
826 : vm_flags_set(vma, VM_HUGEPAGE);
827 : } else {
828 0 : vma->vm_ops = &ext4_file_vm_ops;
829 : }
830 0 : return 0;
831 : }
832 :
833 0 : static int ext4_sample_last_mounted(struct super_block *sb,
834 : struct vfsmount *mnt)
835 : {
836 0 : struct ext4_sb_info *sbi = EXT4_SB(sb);
837 0 : struct path path;
838 0 : char buf[64], *cp;
839 0 : handle_t *handle;
840 0 : int err;
841 :
842 0 : if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
843 : return 0;
844 :
845 0 : if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
846 0 : return 0;
847 :
848 0 : ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
849 : /*
850 : * Sample where the filesystem has been mounted and
851 : * store it in the superblock for sysadmin convenience
852 : * when trying to sort through large numbers of block
853 : * devices or filesystem images.
854 : */
855 0 : memset(buf, 0, sizeof(buf));
856 0 : path.mnt = mnt;
857 0 : path.dentry = mnt->mnt_root;
858 0 : cp = d_path(&path, buf, sizeof(buf));
859 0 : err = 0;
860 0 : if (IS_ERR(cp))
861 0 : goto out;
862 :
863 0 : handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
864 0 : err = PTR_ERR(handle);
865 0 : if (IS_ERR(handle))
866 0 : goto out;
867 0 : BUFFER_TRACE(sbi->s_sbh, "get_write_access");
868 0 : err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
869 : EXT4_JTR_NONE);
870 0 : if (err)
871 0 : goto out_journal;
872 0 : lock_buffer(sbi->s_sbh);
873 0 : strncpy(sbi->s_es->s_last_mounted, cp,
874 : sizeof(sbi->s_es->s_last_mounted));
875 0 : ext4_superblock_csum_set(sb);
876 0 : unlock_buffer(sbi->s_sbh);
877 0 : ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
878 0 : out_journal:
879 0 : ext4_journal_stop(handle);
880 0 : out:
881 0 : sb_end_intwrite(sb);
882 0 : return err;
883 : }
884 :
885 0 : static int ext4_file_open(struct inode *inode, struct file *filp)
886 : {
887 0 : int ret;
888 :
889 0 : if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
890 : return -EIO;
891 :
892 0 : ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
893 0 : if (ret)
894 : return ret;
895 :
896 0 : ret = fscrypt_file_open(inode, filp);
897 0 : if (ret)
898 : return ret;
899 :
900 0 : ret = fsverity_file_open(inode, filp);
901 0 : if (ret)
902 : return ret;
903 :
904 : /*
905 : * Set up the jbd2_inode if we are opening the inode for
906 : * writing and the journal is present
907 : */
908 0 : if (filp->f_mode & FMODE_WRITE) {
909 0 : ret = ext4_inode_attach_jinode(inode);
910 0 : if (ret < 0)
911 : return ret;
912 : }
913 :
914 0 : filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC |
915 : FMODE_DIO_PARALLEL_WRITE;
916 0 : return dquot_file_open(inode, filp);
917 : }
918 :
919 : /*
920 : * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
921 : * by calling generic_file_llseek_size() with the appropriate maxbytes
922 : * value for each.
923 : */
924 0 : loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
925 : {
926 0 : struct inode *inode = file->f_mapping->host;
927 0 : loff_t maxbytes;
928 :
929 0 : if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
930 0 : maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
931 : else
932 0 : maxbytes = inode->i_sb->s_maxbytes;
933 :
934 0 : switch (whence) {
935 : default:
936 0 : return generic_file_llseek_size(file, offset, whence,
937 : maxbytes, i_size_read(inode));
938 : case SEEK_HOLE:
939 0 : inode_lock_shared(inode);
940 0 : offset = iomap_seek_hole(inode, offset,
941 : &ext4_iomap_report_ops);
942 0 : inode_unlock_shared(inode);
943 : break;
944 : case SEEK_DATA:
945 0 : inode_lock_shared(inode);
946 0 : offset = iomap_seek_data(inode, offset,
947 : &ext4_iomap_report_ops);
948 0 : inode_unlock_shared(inode);
949 : break;
950 : }
951 :
952 0 : if (offset < 0)
953 : return offset;
954 0 : return vfs_setpos(file, offset, maxbytes);
955 : }
956 :
957 : const struct file_operations ext4_file_operations = {
958 : .llseek = ext4_llseek,
959 : .read_iter = ext4_file_read_iter,
960 : .write_iter = ext4_file_write_iter,
961 : .iopoll = iocb_bio_iopoll,
962 : .unlocked_ioctl = ext4_ioctl,
963 : #ifdef CONFIG_COMPAT
964 : .compat_ioctl = ext4_compat_ioctl,
965 : #endif
966 : .mmap = ext4_file_mmap,
967 : .mmap_supported_flags = MAP_SYNC,
968 : .open = ext4_file_open,
969 : .release = ext4_release_file,
970 : .fsync = ext4_sync_file,
971 : .get_unmapped_area = thp_get_unmapped_area,
972 : .splice_read = ext4_file_splice_read,
973 : .splice_write = iter_file_splice_write,
974 : .fallocate = ext4_fallocate,
975 : };
976 :
977 : const struct inode_operations ext4_file_inode_operations = {
978 : .setattr = ext4_setattr,
979 : .getattr = ext4_file_getattr,
980 : .listxattr = ext4_listxattr,
981 : .get_inode_acl = ext4_get_acl,
982 : .set_acl = ext4_set_acl,
983 : .fiemap = ext4_fiemap,
984 : .fileattr_get = ext4_fileattr_get,
985 : .fileattr_set = ext4_fileattr_set,
986 : };
987 :
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