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 | static bool ext4_should_use_dio(struct kiocb *iocb, struct iov_iter *iter) |
56 | { |
57 | struct inode *inode = file_inode(f: iocb->ki_filp); |
58 | u32 dio_align = ext4_dio_alignment(inode); |
59 | |
60 | if (dio_align == 0) |
61 | return false; |
62 | |
63 | if (dio_align == 1) |
64 | return true; |
65 | |
66 | return IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter), dio_align); |
67 | } |
68 | |
69 | static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) |
70 | { |
71 | ssize_t ret; |
72 | struct inode *inode = file_inode(f: iocb->ki_filp); |
73 | |
74 | if (iocb->ki_flags & IOCB_NOWAIT) { |
75 | if (!inode_trylock_shared(inode)) |
76 | return -EAGAIN; |
77 | } else { |
78 | inode_lock_shared(inode); |
79 | } |
80 | |
81 | if (!ext4_should_use_dio(iocb, iter: to)) { |
82 | inode_unlock_shared(inode); |
83 | /* |
84 | * Fallback to buffered I/O if the operation being performed on |
85 | * the inode is not supported by direct I/O. The IOCB_DIRECT |
86 | * flag needs to be cleared here in order to ensure that the |
87 | * direct I/O path within generic_file_read_iter() is not |
88 | * taken. |
89 | */ |
90 | iocb->ki_flags &= ~IOCB_DIRECT; |
91 | return generic_file_read_iter(iocb, to); |
92 | } |
93 | |
94 | ret = iomap_dio_rw(iocb, iter: to, ops: &ext4_iomap_ops, NULL, dio_flags: 0, NULL, done_before: 0); |
95 | inode_unlock_shared(inode); |
96 | |
97 | file_accessed(file: iocb->ki_filp); |
98 | 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(f: 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, iter: to, ops: &ext4_iomap_ops); |
123 | inode_unlock_shared(inode); |
124 | |
125 | file_accessed(file: iocb->ki_filp); |
126 | return ret; |
127 | } |
128 | #endif |
129 | |
130 | static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to) |
131 | { |
132 | struct inode *inode = file_inode(f: iocb->ki_filp); |
133 | |
134 | if (unlikely(ext4_forced_shutdown(inode->i_sb))) |
135 | return -EIO; |
136 | |
137 | if (!iov_iter_count(i: to)) |
138 | return 0; /* skip atime */ |
139 | |
140 | #ifdef CONFIG_FS_DAX |
141 | if (IS_DAX(inode)) |
142 | return ext4_dax_read_iter(iocb, to); |
143 | #endif |
144 | if (iocb->ki_flags & IOCB_DIRECT) |
145 | return ext4_dio_read_iter(iocb, to); |
146 | |
147 | return generic_file_read_iter(iocb, to); |
148 | } |
149 | |
150 | 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 | struct inode *inode = file_inode(f: in); |
155 | |
156 | if (unlikely(ext4_forced_shutdown(inode->i_sb))) |
157 | return -EIO; |
158 | 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 | static int ext4_release_file(struct inode *inode, struct file *filp) |
167 | { |
168 | if (ext4_test_inode_state(inode, bit: EXT4_STATE_DA_ALLOC_CLOSE)) { |
169 | ext4_alloc_da_blocks(inode); |
170 | ext4_clear_inode_state(inode, bit: EXT4_STATE_DA_ALLOC_CLOSE); |
171 | } |
172 | /* if we are the last writer on the inode, drop the block reservation */ |
173 | if ((filp->f_mode & FMODE_WRITE) && |
174 | (atomic_read(v: &inode->i_writecount) == 1) && |
175 | !EXT4_I(inode)->i_reserved_data_blocks) { |
176 | down_write(sem: &EXT4_I(inode)->i_data_sem); |
177 | ext4_discard_preallocations(inode); |
178 | up_write(sem: &EXT4_I(inode)->i_data_sem); |
179 | } |
180 | if (is_dx(inode) && filp->private_data) |
181 | ext4_htree_free_dir_info(p: filp->private_data); |
182 | |
183 | 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 | ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos) |
197 | { |
198 | struct super_block *sb = inode->i_sb; |
199 | unsigned long blockmask = sb->s_blocksize - 1; |
200 | |
201 | if ((pos | iov_iter_alignment(i: from)) & blockmask) |
202 | 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 | if (offset + len > i_size_read(inode) || |
211 | offset + len > EXT4_I(inode)->i_disksize) |
212 | return true; |
213 | return false; |
214 | } |
215 | |
216 | /* Is IO overwriting allocated or initialized blocks? */ |
217 | static bool ext4_overwrite_io(struct inode *inode, |
218 | loff_t pos, loff_t len, bool *unwritten) |
219 | { |
220 | struct ext4_map_blocks map; |
221 | unsigned int blkbits = inode->i_blkbits; |
222 | int err, blklen; |
223 | |
224 | if (pos + len > i_size_read(inode)) |
225 | return false; |
226 | |
227 | map.m_lblk = pos >> blkbits; |
228 | map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits); |
229 | blklen = map.m_len; |
230 | |
231 | err = ext4_map_blocks(NULL, inode, map: &map, flags: 0); |
232 | 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 | *unwritten = !(map.m_flags & EXT4_MAP_MAPPED); |
240 | return true; |
241 | } |
242 | |
243 | static ssize_t ext4_generic_write_checks(struct kiocb *iocb, |
244 | struct iov_iter *from) |
245 | { |
246 | struct inode *inode = file_inode(f: iocb->ki_filp); |
247 | ssize_t ret; |
248 | |
249 | if (unlikely(IS_IMMUTABLE(inode))) |
250 | return -EPERM; |
251 | |
252 | ret = generic_write_checks(iocb, from); |
253 | 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 | if (!(ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))) { |
261 | struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb); |
262 | |
263 | if (iocb->ki_pos >= sbi->s_bitmap_maxbytes) |
264 | return -EFBIG; |
265 | iov_iter_truncate(i: from, count: sbi->s_bitmap_maxbytes - iocb->ki_pos); |
266 | } |
267 | |
268 | return iov_iter_count(i: from); |
269 | } |
270 | |
271 | static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) |
272 | { |
273 | ssize_t ret, count; |
274 | |
275 | count = ext4_generic_write_checks(iocb, from); |
276 | if (count <= 0) |
277 | return count; |
278 | |
279 | ret = file_modified(file: iocb->ki_filp); |
280 | if (ret) |
281 | return ret; |
282 | return count; |
283 | } |
284 | |
285 | static ssize_t ext4_buffered_write_iter(struct kiocb *iocb, |
286 | struct iov_iter *from) |
287 | { |
288 | ssize_t ret; |
289 | struct inode *inode = file_inode(f: iocb->ki_filp); |
290 | |
291 | if (iocb->ki_flags & IOCB_NOWAIT) |
292 | return -EOPNOTSUPP; |
293 | |
294 | inode_lock(inode); |
295 | ret = ext4_write_checks(iocb, from); |
296 | if (ret <= 0) |
297 | goto out; |
298 | |
299 | ret = generic_perform_write(iocb, from); |
300 | |
301 | out: |
302 | inode_unlock(inode); |
303 | if (unlikely(ret <= 0)) |
304 | return ret; |
305 | return generic_write_sync(iocb, count: ret); |
306 | } |
307 | |
308 | static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset, |
309 | ssize_t count) |
310 | { |
311 | handle_t *handle; |
312 | |
313 | lockdep_assert_held_write(&inode->i_rwsem); |
314 | handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); |
315 | if (IS_ERR(ptr: handle)) |
316 | return PTR_ERR(ptr: handle); |
317 | |
318 | if (ext4_update_inode_size(inode, newsize: offset + count)) { |
319 | int ret = ext4_mark_inode_dirty(handle, inode); |
320 | if (unlikely(ret)) { |
321 | ext4_journal_stop(handle); |
322 | return ret; |
323 | } |
324 | } |
325 | |
326 | if (inode->i_nlink) |
327 | ext4_orphan_del(handle, inode); |
328 | ext4_journal_stop(handle); |
329 | |
330 | return count; |
331 | } |
332 | |
333 | /* |
334 | * Clean up the inode after DIO or DAX extending write has completed and the |
335 | * inode size has been updated using ext4_handle_inode_extension(). |
336 | */ |
337 | static void ext4_inode_extension_cleanup(struct inode *inode, ssize_t count) |
338 | { |
339 | lockdep_assert_held_write(&inode->i_rwsem); |
340 | if (count < 0) { |
341 | ext4_truncate_failed_write(inode); |
342 | /* |
343 | * If the truncate operation failed early, then the inode may |
344 | * still be on the orphan list. In that case, we need to try |
345 | * remove the inode from the in-memory linked list. |
346 | */ |
347 | if (inode->i_nlink) |
348 | ext4_orphan_del(NULL, inode); |
349 | return; |
350 | } |
351 | /* |
352 | * If i_disksize got extended either due to writeback of delalloc |
353 | * blocks or extending truncate while the DIO was running we could fail |
354 | * to cleanup the orphan list in ext4_handle_inode_extension(). Do it |
355 | * now. |
356 | */ |
357 | if (!list_empty(head: &EXT4_I(inode)->i_orphan) && inode->i_nlink) { |
358 | handle_t *handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); |
359 | |
360 | if (IS_ERR(ptr: handle)) { |
361 | /* |
362 | * The write has successfully completed. Not much to |
363 | * do with the error here so just cleanup the orphan |
364 | * list and hope for the best. |
365 | */ |
366 | ext4_orphan_del(NULL, inode); |
367 | return; |
368 | } |
369 | ext4_orphan_del(handle, inode); |
370 | ext4_journal_stop(handle); |
371 | } |
372 | } |
373 | |
374 | static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size, |
375 | int error, unsigned int flags) |
376 | { |
377 | loff_t pos = iocb->ki_pos; |
378 | struct inode *inode = file_inode(f: iocb->ki_filp); |
379 | |
380 | if (!error && size && flags & IOMAP_DIO_UNWRITTEN) |
381 | error = ext4_convert_unwritten_extents(NULL, inode, offset: pos, len: size); |
382 | if (error) |
383 | return error; |
384 | /* |
385 | * Note that EXT4_I(inode)->i_disksize can get extended up to |
386 | * inode->i_size while the I/O was running due to writeback of delalloc |
387 | * blocks. But the code in ext4_iomap_alloc() is careful to use |
388 | * zeroed/unwritten extents if this is possible; thus we won't leave |
389 | * uninitialized blocks in a file even if we didn't succeed in writing |
390 | * as much as we intended. Also we can race with truncate or write |
391 | * expanding the file so we have to be a bit careful here. |
392 | */ |
393 | if (pos + size <= READ_ONCE(EXT4_I(inode)->i_disksize) && |
394 | pos + size <= i_size_read(inode)) |
395 | return size; |
396 | return ext4_handle_inode_extension(inode, offset: pos, count: size); |
397 | } |
398 | |
399 | static const struct iomap_dio_ops ext4_dio_write_ops = { |
400 | .end_io = ext4_dio_write_end_io, |
401 | }; |
402 | |
403 | /* |
404 | * The intention here is to start with shared lock acquired then see if any |
405 | * condition requires an exclusive inode lock. If yes, then we restart the |
406 | * whole operation by releasing the shared lock and acquiring exclusive lock. |
407 | * |
408 | * - For unaligned_io we never take shared lock as it may cause data corruption |
409 | * when two unaligned IO tries to modify the same block e.g. while zeroing. |
410 | * |
411 | * - For extending writes case we don't take the shared lock, since it requires |
412 | * updating inode i_disksize and/or orphan handling with exclusive lock. |
413 | * |
414 | * - shared locking will only be true mostly with overwrites, including |
415 | * initialized blocks and unwritten blocks. For overwrite unwritten blocks |
416 | * we protect splitting extents by i_data_sem in ext4_inode_info, so we can |
417 | * also release exclusive i_rwsem lock. |
418 | * |
419 | * - Otherwise we will switch to exclusive i_rwsem lock. |
420 | */ |
421 | static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from, |
422 | bool *ilock_shared, bool *extend, |
423 | bool *unwritten, int *dio_flags) |
424 | { |
425 | struct file *file = iocb->ki_filp; |
426 | struct inode *inode = file_inode(f: file); |
427 | loff_t offset; |
428 | size_t count; |
429 | ssize_t ret; |
430 | bool overwrite, unaligned_io; |
431 | |
432 | restart: |
433 | ret = ext4_generic_write_checks(iocb, from); |
434 | if (ret <= 0) |
435 | goto out; |
436 | |
437 | offset = iocb->ki_pos; |
438 | count = ret; |
439 | |
440 | unaligned_io = ext4_unaligned_io(inode, from, pos: offset); |
441 | *extend = ext4_extending_io(inode, offset, len: count); |
442 | overwrite = ext4_overwrite_io(inode, pos: offset, len: count, unwritten); |
443 | |
444 | /* |
445 | * Determine whether we need to upgrade to an exclusive lock. This is |
446 | * required to change security info in file_modified(), for extending |
447 | * I/O, any form of non-overwrite I/O, and unaligned I/O to unwritten |
448 | * extents (as partial block zeroing may be required). |
449 | * |
450 | * Note that unaligned writes are allowed under shared lock so long as |
451 | * they are pure overwrites. Otherwise, concurrent unaligned writes risk |
452 | * data corruption due to partial block zeroing in the dio layer, and so |
453 | * the I/O must occur exclusively. |
454 | */ |
455 | if (*ilock_shared && |
456 | ((!IS_NOSEC(inode) || *extend || !overwrite || |
457 | (unaligned_io && *unwritten)))) { |
458 | if (iocb->ki_flags & IOCB_NOWAIT) { |
459 | ret = -EAGAIN; |
460 | goto out; |
461 | } |
462 | inode_unlock_shared(inode); |
463 | *ilock_shared = false; |
464 | inode_lock(inode); |
465 | goto restart; |
466 | } |
467 | |
468 | /* |
469 | * Now that locking is settled, determine dio flags and exclusivity |
470 | * requirements. We don't use DIO_OVERWRITE_ONLY because we enforce |
471 | * behavior already. The inode lock is already held exclusive if the |
472 | * write is non-overwrite or extending, so drain all outstanding dio and |
473 | * set the force wait dio flag. |
474 | */ |
475 | if (!*ilock_shared && (unaligned_io || *extend)) { |
476 | if (iocb->ki_flags & IOCB_NOWAIT) { |
477 | ret = -EAGAIN; |
478 | goto out; |
479 | } |
480 | if (unaligned_io && (!overwrite || *unwritten)) |
481 | inode_dio_wait(inode); |
482 | *dio_flags = IOMAP_DIO_FORCE_WAIT; |
483 | } |
484 | |
485 | ret = file_modified(file); |
486 | if (ret < 0) |
487 | goto out; |
488 | |
489 | return count; |
490 | out: |
491 | if (*ilock_shared) |
492 | inode_unlock_shared(inode); |
493 | else |
494 | inode_unlock(inode); |
495 | return ret; |
496 | } |
497 | |
498 | static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) |
499 | { |
500 | ssize_t ret; |
501 | handle_t *handle; |
502 | struct inode *inode = file_inode(f: iocb->ki_filp); |
503 | loff_t offset = iocb->ki_pos; |
504 | size_t count = iov_iter_count(i: from); |
505 | const struct iomap_ops *iomap_ops = &ext4_iomap_ops; |
506 | bool extend = false, unwritten = false; |
507 | bool ilock_shared = true; |
508 | int dio_flags = 0; |
509 | |
510 | /* |
511 | * Quick check here without any i_rwsem lock to see if it is extending |
512 | * IO. A more reliable check is done in ext4_dio_write_checks() with |
513 | * proper locking in place. |
514 | */ |
515 | if (offset + count > i_size_read(inode)) |
516 | ilock_shared = false; |
517 | |
518 | if (iocb->ki_flags & IOCB_NOWAIT) { |
519 | if (ilock_shared) { |
520 | if (!inode_trylock_shared(inode)) |
521 | return -EAGAIN; |
522 | } else { |
523 | if (!inode_trylock(inode)) |
524 | return -EAGAIN; |
525 | } |
526 | } else { |
527 | if (ilock_shared) |
528 | inode_lock_shared(inode); |
529 | else |
530 | inode_lock(inode); |
531 | } |
532 | |
533 | /* Fallback to buffered I/O if the inode does not support direct I/O. */ |
534 | if (!ext4_should_use_dio(iocb, iter: from)) { |
535 | if (ilock_shared) |
536 | inode_unlock_shared(inode); |
537 | else |
538 | inode_unlock(inode); |
539 | return ext4_buffered_write_iter(iocb, from); |
540 | } |
541 | |
542 | /* |
543 | * Prevent inline data from being created since we are going to allocate |
544 | * blocks for DIO. We know the inode does not currently have inline data |
545 | * because ext4_should_use_dio() checked for it, but we have to clear |
546 | * the state flag before the write checks because a lock cycle could |
547 | * introduce races with other writers. |
548 | */ |
549 | ext4_clear_inode_state(inode, bit: EXT4_STATE_MAY_INLINE_DATA); |
550 | |
551 | ret = ext4_dio_write_checks(iocb, from, ilock_shared: &ilock_shared, extend: &extend, |
552 | unwritten: &unwritten, dio_flags: &dio_flags); |
553 | if (ret <= 0) |
554 | return ret; |
555 | |
556 | offset = iocb->ki_pos; |
557 | count = ret; |
558 | |
559 | if (extend) { |
560 | handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); |
561 | if (IS_ERR(ptr: handle)) { |
562 | ret = PTR_ERR(ptr: handle); |
563 | goto out; |
564 | } |
565 | |
566 | ret = ext4_orphan_add(handle, inode); |
567 | if (ret) { |
568 | ext4_journal_stop(handle); |
569 | goto out; |
570 | } |
571 | |
572 | ext4_journal_stop(handle); |
573 | } |
574 | |
575 | if (ilock_shared && !unwritten) |
576 | iomap_ops = &ext4_iomap_overwrite_ops; |
577 | ret = iomap_dio_rw(iocb, iter: from, ops: iomap_ops, dops: &ext4_dio_write_ops, |
578 | dio_flags, NULL, done_before: 0); |
579 | if (ret == -ENOTBLK) |
580 | ret = 0; |
581 | if (extend) { |
582 | /* |
583 | * We always perform extending DIO write synchronously so by |
584 | * now the IO is completed and ext4_handle_inode_extension() |
585 | * was called. Cleanup the inode in case of error or race with |
586 | * writeback of delalloc blocks. |
587 | */ |
588 | WARN_ON_ONCE(ret == -EIOCBQUEUED); |
589 | ext4_inode_extension_cleanup(inode, count: ret); |
590 | } |
591 | |
592 | out: |
593 | if (ilock_shared) |
594 | inode_unlock_shared(inode); |
595 | else |
596 | inode_unlock(inode); |
597 | |
598 | if (ret >= 0 && iov_iter_count(i: from)) { |
599 | ssize_t err; |
600 | loff_t endbyte; |
601 | |
602 | offset = iocb->ki_pos; |
603 | err = ext4_buffered_write_iter(iocb, from); |
604 | if (err < 0) |
605 | return err; |
606 | |
607 | /* |
608 | * We need to ensure that the pages within the page cache for |
609 | * the range covered by this I/O are written to disk and |
610 | * invalidated. This is in attempt to preserve the expected |
611 | * direct I/O semantics in the case we fallback to buffered I/O |
612 | * to complete off the I/O request. |
613 | */ |
614 | ret += err; |
615 | endbyte = offset + err - 1; |
616 | err = filemap_write_and_wait_range(mapping: iocb->ki_filp->f_mapping, |
617 | lstart: offset, lend: endbyte); |
618 | if (!err) |
619 | invalidate_mapping_pages(mapping: iocb->ki_filp->f_mapping, |
620 | start: offset >> PAGE_SHIFT, |
621 | end: endbyte >> PAGE_SHIFT); |
622 | } |
623 | |
624 | return ret; |
625 | } |
626 | |
627 | #ifdef CONFIG_FS_DAX |
628 | static ssize_t |
629 | ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) |
630 | { |
631 | ssize_t ret; |
632 | size_t count; |
633 | loff_t offset; |
634 | handle_t *handle; |
635 | bool extend = false; |
636 | struct inode *inode = file_inode(f: iocb->ki_filp); |
637 | |
638 | if (iocb->ki_flags & IOCB_NOWAIT) { |
639 | if (!inode_trylock(inode)) |
640 | return -EAGAIN; |
641 | } else { |
642 | inode_lock(inode); |
643 | } |
644 | |
645 | ret = ext4_write_checks(iocb, from); |
646 | if (ret <= 0) |
647 | goto out; |
648 | |
649 | offset = iocb->ki_pos; |
650 | count = iov_iter_count(i: from); |
651 | |
652 | if (offset + count > EXT4_I(inode)->i_disksize) { |
653 | handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); |
654 | if (IS_ERR(ptr: handle)) { |
655 | ret = PTR_ERR(ptr: handle); |
656 | goto out; |
657 | } |
658 | |
659 | ret = ext4_orphan_add(handle, inode); |
660 | if (ret) { |
661 | ext4_journal_stop(handle); |
662 | goto out; |
663 | } |
664 | |
665 | extend = true; |
666 | ext4_journal_stop(handle); |
667 | } |
668 | |
669 | ret = dax_iomap_rw(iocb, iter: from, ops: &ext4_iomap_ops); |
670 | |
671 | if (extend) { |
672 | ret = ext4_handle_inode_extension(inode, offset, count: ret); |
673 | ext4_inode_extension_cleanup(inode, count: ret); |
674 | } |
675 | out: |
676 | inode_unlock(inode); |
677 | if (ret > 0) |
678 | ret = generic_write_sync(iocb, count: ret); |
679 | return ret; |
680 | } |
681 | #endif |
682 | |
683 | static ssize_t |
684 | ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) |
685 | { |
686 | struct inode *inode = file_inode(f: iocb->ki_filp); |
687 | |
688 | if (unlikely(ext4_forced_shutdown(inode->i_sb))) |
689 | return -EIO; |
690 | |
691 | #ifdef CONFIG_FS_DAX |
692 | if (IS_DAX(inode)) |
693 | return ext4_dax_write_iter(iocb, from); |
694 | #endif |
695 | if (iocb->ki_flags & IOCB_DIRECT) |
696 | return ext4_dio_write_iter(iocb, from); |
697 | else |
698 | return ext4_buffered_write_iter(iocb, from); |
699 | } |
700 | |
701 | #ifdef CONFIG_FS_DAX |
702 | static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, unsigned int order) |
703 | { |
704 | int error = 0; |
705 | vm_fault_t result; |
706 | int retries = 0; |
707 | handle_t *handle = NULL; |
708 | struct inode *inode = file_inode(f: vmf->vma->vm_file); |
709 | struct super_block *sb = inode->i_sb; |
710 | |
711 | /* |
712 | * We have to distinguish real writes from writes which will result in a |
713 | * COW page; COW writes should *not* poke the journal (the file will not |
714 | * be changed). Doing so would cause unintended failures when mounted |
715 | * read-only. |
716 | * |
717 | * We check for VM_SHARED rather than vmf->cow_page since the latter is |
718 | * unset for order != 0 (i.e. only in do_cow_fault); for |
719 | * other sizes, dax_iomap_fault will handle splitting / fallback so that |
720 | * we eventually come back with a COW page. |
721 | */ |
722 | bool write = (vmf->flags & FAULT_FLAG_WRITE) && |
723 | (vmf->vma->vm_flags & VM_SHARED); |
724 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
725 | pfn_t pfn; |
726 | |
727 | if (write) { |
728 | sb_start_pagefault(sb); |
729 | file_update_time(file: vmf->vma->vm_file); |
730 | filemap_invalidate_lock_shared(mapping); |
731 | retry: |
732 | handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, |
733 | EXT4_DATA_TRANS_BLOCKS(sb)); |
734 | if (IS_ERR(ptr: handle)) { |
735 | filemap_invalidate_unlock_shared(mapping); |
736 | sb_end_pagefault(sb); |
737 | return VM_FAULT_SIGBUS; |
738 | } |
739 | } else { |
740 | filemap_invalidate_lock_shared(mapping); |
741 | } |
742 | result = dax_iomap_fault(vmf, order, pfnp: &pfn, errp: &error, ops: &ext4_iomap_ops); |
743 | if (write) { |
744 | ext4_journal_stop(handle); |
745 | |
746 | if ((result & VM_FAULT_ERROR) && error == -ENOSPC && |
747 | ext4_should_retry_alloc(sb, retries: &retries)) |
748 | goto retry; |
749 | /* Handling synchronous page fault? */ |
750 | if (result & VM_FAULT_NEEDDSYNC) |
751 | result = dax_finish_sync_fault(vmf, order, pfn); |
752 | filemap_invalidate_unlock_shared(mapping); |
753 | sb_end_pagefault(sb); |
754 | } else { |
755 | filemap_invalidate_unlock_shared(mapping); |
756 | } |
757 | |
758 | return result; |
759 | } |
760 | |
761 | static vm_fault_t ext4_dax_fault(struct vm_fault *vmf) |
762 | { |
763 | return ext4_dax_huge_fault(vmf, order: 0); |
764 | } |
765 | |
766 | static const struct vm_operations_struct ext4_dax_vm_ops = { |
767 | .fault = ext4_dax_fault, |
768 | .huge_fault = ext4_dax_huge_fault, |
769 | .page_mkwrite = ext4_dax_fault, |
770 | .pfn_mkwrite = ext4_dax_fault, |
771 | }; |
772 | #else |
773 | #define ext4_dax_vm_ops ext4_file_vm_ops |
774 | #endif |
775 | |
776 | static const struct vm_operations_struct ext4_file_vm_ops = { |
777 | .fault = filemap_fault, |
778 | .map_pages = filemap_map_pages, |
779 | .page_mkwrite = ext4_page_mkwrite, |
780 | }; |
781 | |
782 | static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma) |
783 | { |
784 | struct inode *inode = file->f_mapping->host; |
785 | struct dax_device *dax_dev = EXT4_SB(sb: inode->i_sb)->s_daxdev; |
786 | |
787 | if (unlikely(ext4_forced_shutdown(inode->i_sb))) |
788 | return -EIO; |
789 | |
790 | /* |
791 | * We don't support synchronous mappings for non-DAX files and |
792 | * for DAX files if underneath dax_device is not synchronous. |
793 | */ |
794 | if (!daxdev_mapping_supported(vma, dax_dev)) |
795 | return -EOPNOTSUPP; |
796 | |
797 | file_accessed(file); |
798 | if (IS_DAX(file_inode(file))) { |
799 | vma->vm_ops = &ext4_dax_vm_ops; |
800 | vm_flags_set(vma, VM_HUGEPAGE); |
801 | } else { |
802 | vma->vm_ops = &ext4_file_vm_ops; |
803 | } |
804 | return 0; |
805 | } |
806 | |
807 | static int ext4_sample_last_mounted(struct super_block *sb, |
808 | struct vfsmount *mnt) |
809 | { |
810 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
811 | struct path path; |
812 | char buf[64], *cp; |
813 | handle_t *handle; |
814 | int err; |
815 | |
816 | if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED))) |
817 | return 0; |
818 | |
819 | if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb)) |
820 | return 0; |
821 | |
822 | ext4_set_mount_flag(sb, bit: EXT4_MF_MNTDIR_SAMPLED); |
823 | /* |
824 | * Sample where the filesystem has been mounted and |
825 | * store it in the superblock for sysadmin convenience |
826 | * when trying to sort through large numbers of block |
827 | * devices or filesystem images. |
828 | */ |
829 | memset(buf, 0, sizeof(buf)); |
830 | path.mnt = mnt; |
831 | path.dentry = mnt->mnt_root; |
832 | cp = d_path(&path, buf, sizeof(buf)); |
833 | err = 0; |
834 | if (IS_ERR(ptr: cp)) |
835 | goto out; |
836 | |
837 | handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1); |
838 | err = PTR_ERR(ptr: handle); |
839 | if (IS_ERR(ptr: handle)) |
840 | goto out; |
841 | BUFFER_TRACE(sbi->s_sbh, "get_write_access" ); |
842 | err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh, |
843 | EXT4_JTR_NONE); |
844 | if (err) |
845 | goto out_journal; |
846 | lock_buffer(bh: sbi->s_sbh); |
847 | strncpy(p: sbi->s_es->s_last_mounted, q: cp, |
848 | size: sizeof(sbi->s_es->s_last_mounted)); |
849 | ext4_superblock_csum_set(sb); |
850 | unlock_buffer(bh: sbi->s_sbh); |
851 | ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh); |
852 | out_journal: |
853 | ext4_journal_stop(handle); |
854 | out: |
855 | sb_end_intwrite(sb); |
856 | return err; |
857 | } |
858 | |
859 | static int ext4_file_open(struct inode *inode, struct file *filp) |
860 | { |
861 | int ret; |
862 | |
863 | if (unlikely(ext4_forced_shutdown(inode->i_sb))) |
864 | return -EIO; |
865 | |
866 | ret = ext4_sample_last_mounted(sb: inode->i_sb, mnt: filp->f_path.mnt); |
867 | if (ret) |
868 | return ret; |
869 | |
870 | ret = fscrypt_file_open(inode, filp); |
871 | if (ret) |
872 | return ret; |
873 | |
874 | ret = fsverity_file_open(inode, filp); |
875 | if (ret) |
876 | return ret; |
877 | |
878 | /* |
879 | * Set up the jbd2_inode if we are opening the inode for |
880 | * writing and the journal is present |
881 | */ |
882 | if (filp->f_mode & FMODE_WRITE) { |
883 | ret = ext4_inode_attach_jinode(inode); |
884 | if (ret < 0) |
885 | return ret; |
886 | } |
887 | |
888 | filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | |
889 | FMODE_DIO_PARALLEL_WRITE; |
890 | return dquot_file_open(inode, file: filp); |
891 | } |
892 | |
893 | /* |
894 | * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values |
895 | * by calling generic_file_llseek_size() with the appropriate maxbytes |
896 | * value for each. |
897 | */ |
898 | loff_t ext4_llseek(struct file *file, loff_t offset, int whence) |
899 | { |
900 | struct inode *inode = file->f_mapping->host; |
901 | loff_t maxbytes; |
902 | |
903 | if (!(ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))) |
904 | maxbytes = EXT4_SB(sb: inode->i_sb)->s_bitmap_maxbytes; |
905 | else |
906 | maxbytes = inode->i_sb->s_maxbytes; |
907 | |
908 | switch (whence) { |
909 | default: |
910 | return generic_file_llseek_size(file, offset, whence, |
911 | maxsize: maxbytes, eof: i_size_read(inode)); |
912 | case SEEK_HOLE: |
913 | inode_lock_shared(inode); |
914 | offset = iomap_seek_hole(inode, offset, |
915 | ops: &ext4_iomap_report_ops); |
916 | inode_unlock_shared(inode); |
917 | break; |
918 | case SEEK_DATA: |
919 | inode_lock_shared(inode); |
920 | offset = iomap_seek_data(inode, offset, |
921 | ops: &ext4_iomap_report_ops); |
922 | inode_unlock_shared(inode); |
923 | break; |
924 | } |
925 | |
926 | if (offset < 0) |
927 | return offset; |
928 | return vfs_setpos(file, offset, maxsize: maxbytes); |
929 | } |
930 | |
931 | const struct file_operations ext4_file_operations = { |
932 | .llseek = ext4_llseek, |
933 | .read_iter = ext4_file_read_iter, |
934 | .write_iter = ext4_file_write_iter, |
935 | .iopoll = iocb_bio_iopoll, |
936 | .unlocked_ioctl = ext4_ioctl, |
937 | #ifdef CONFIG_COMPAT |
938 | .compat_ioctl = ext4_compat_ioctl, |
939 | #endif |
940 | .mmap = ext4_file_mmap, |
941 | .mmap_supported_flags = MAP_SYNC, |
942 | .open = ext4_file_open, |
943 | .release = ext4_release_file, |
944 | .fsync = ext4_sync_file, |
945 | .get_unmapped_area = thp_get_unmapped_area, |
946 | .splice_read = ext4_file_splice_read, |
947 | .splice_write = iter_file_splice_write, |
948 | .fallocate = ext4_fallocate, |
949 | }; |
950 | |
951 | const struct inode_operations ext4_file_inode_operations = { |
952 | .setattr = ext4_setattr, |
953 | .getattr = ext4_file_getattr, |
954 | .listxattr = ext4_listxattr, |
955 | .get_inode_acl = ext4_get_acl, |
956 | .set_acl = ext4_set_acl, |
957 | .fiemap = ext4_fiemap, |
958 | .fileattr_get = ext4_fileattr_get, |
959 | .fileattr_set = ext4_fileattr_set, |
960 | }; |
961 | |
962 | |