Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * linux/fs/ext4/page-io.c
4 : *
5 : * This contains the new page_io functions for ext4
6 : *
7 : * Written by Theodore Ts'o, 2010.
8 : */
9 :
10 : #include <linux/fs.h>
11 : #include <linux/time.h>
12 : #include <linux/highuid.h>
13 : #include <linux/pagemap.h>
14 : #include <linux/quotaops.h>
15 : #include <linux/string.h>
16 : #include <linux/buffer_head.h>
17 : #include <linux/writeback.h>
18 : #include <linux/pagevec.h>
19 : #include <linux/mpage.h>
20 : #include <linux/namei.h>
21 : #include <linux/uio.h>
22 : #include <linux/bio.h>
23 : #include <linux/workqueue.h>
24 : #include <linux/kernel.h>
25 : #include <linux/slab.h>
26 : #include <linux/mm.h>
27 : #include <linux/sched/mm.h>
28 :
29 : #include "ext4_jbd2.h"
30 : #include "xattr.h"
31 : #include "acl.h"
32 :
33 : static struct kmem_cache *io_end_cachep;
34 : static struct kmem_cache *io_end_vec_cachep;
35 :
36 2 : int __init ext4_init_pageio(void)
37 : {
38 2 : io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
39 2 : if (io_end_cachep == NULL)
40 : return -ENOMEM;
41 :
42 2 : io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0);
43 2 : if (io_end_vec_cachep == NULL) {
44 0 : kmem_cache_destroy(io_end_cachep);
45 0 : return -ENOMEM;
46 : }
47 : return 0;
48 : }
49 :
50 0 : void ext4_exit_pageio(void)
51 : {
52 0 : kmem_cache_destroy(io_end_cachep);
53 0 : kmem_cache_destroy(io_end_vec_cachep);
54 0 : }
55 :
56 0 : struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end)
57 : {
58 0 : struct ext4_io_end_vec *io_end_vec;
59 :
60 0 : io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS);
61 0 : if (!io_end_vec)
62 : return ERR_PTR(-ENOMEM);
63 0 : INIT_LIST_HEAD(&io_end_vec->list);
64 0 : list_add_tail(&io_end_vec->list, &io_end->list_vec);
65 0 : return io_end_vec;
66 : }
67 :
68 0 : static void ext4_free_io_end_vec(ext4_io_end_t *io_end)
69 : {
70 0 : struct ext4_io_end_vec *io_end_vec, *tmp;
71 :
72 0 : if (list_empty(&io_end->list_vec))
73 : return;
74 0 : list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) {
75 0 : list_del(&io_end_vec->list);
76 0 : kmem_cache_free(io_end_vec_cachep, io_end_vec);
77 : }
78 : }
79 :
80 0 : struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end)
81 : {
82 0 : BUG_ON(list_empty(&io_end->list_vec));
83 0 : return list_last_entry(&io_end->list_vec, struct ext4_io_end_vec, list);
84 : }
85 :
86 : /*
87 : * Print an buffer I/O error compatible with the fs/buffer.c. This
88 : * provides compatibility with dmesg scrapers that look for a specific
89 : * buffer I/O error message. We really need a unified error reporting
90 : * structure to userspace ala Digital Unix's uerf system, but it's
91 : * probably not going to happen in my lifetime, due to LKML politics...
92 : */
93 0 : static void buffer_io_error(struct buffer_head *bh)
94 : {
95 0 : printk_ratelimited(KERN_ERR "Buffer I/O error on device %pg, logical block %llu\n",
96 : bh->b_bdev,
97 : (unsigned long long)bh->b_blocknr);
98 0 : }
99 :
100 0 : static void ext4_finish_bio(struct bio *bio)
101 : {
102 0 : struct folio_iter fi;
103 :
104 0 : bio_for_each_folio_all(fi, bio) {
105 0 : struct folio *folio = fi.folio;
106 0 : struct folio *io_folio = NULL;
107 0 : struct buffer_head *bh, *head;
108 0 : size_t bio_start = fi.offset;
109 0 : size_t bio_end = bio_start + fi.length;
110 0 : unsigned under_io = 0;
111 0 : unsigned long flags;
112 :
113 0 : if (fscrypt_is_bounce_folio(folio)) {
114 : io_folio = folio;
115 : folio = fscrypt_pagecache_folio(folio);
116 : }
117 :
118 0 : if (bio->bi_status) {
119 0 : int err = blk_status_to_errno(bio->bi_status);
120 0 : folio_set_error(folio);
121 0 : mapping_set_error(folio->mapping, err);
122 : }
123 0 : bh = head = folio_buffers(folio);
124 : /*
125 : * We check all buffers in the folio under b_uptodate_lock
126 : * to avoid races with other end io clearing async_write flags
127 : */
128 0 : spin_lock_irqsave(&head->b_uptodate_lock, flags);
129 0 : do {
130 0 : if (bh_offset(bh) < bio_start ||
131 0 : bh_offset(bh) + bh->b_size > bio_end) {
132 0 : if (buffer_async_write(bh))
133 0 : under_io++;
134 0 : continue;
135 : }
136 0 : clear_buffer_async_write(bh);
137 0 : if (bio->bi_status) {
138 0 : set_buffer_write_io_error(bh);
139 0 : buffer_io_error(bh);
140 : }
141 0 : } while ((bh = bh->b_this_page) != head);
142 0 : spin_unlock_irqrestore(&head->b_uptodate_lock, flags);
143 0 : if (!under_io) {
144 0 : fscrypt_free_bounce_page(&io_folio->page);
145 0 : folio_end_writeback(folio);
146 : }
147 : }
148 0 : }
149 :
150 0 : static void ext4_release_io_end(ext4_io_end_t *io_end)
151 : {
152 0 : struct bio *bio, *next_bio;
153 :
154 0 : BUG_ON(!list_empty(&io_end->list));
155 0 : BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
156 0 : WARN_ON(io_end->handle);
157 :
158 0 : for (bio = io_end->bio; bio; bio = next_bio) {
159 0 : next_bio = bio->bi_private;
160 0 : ext4_finish_bio(bio);
161 0 : bio_put(bio);
162 : }
163 0 : ext4_free_io_end_vec(io_end);
164 0 : kmem_cache_free(io_end_cachep, io_end);
165 0 : }
166 :
167 : /*
168 : * Check a range of space and convert unwritten extents to written. Note that
169 : * we are protected from truncate touching same part of extent tree by the
170 : * fact that truncate code waits for all DIO to finish (thus exclusion from
171 : * direct IO is achieved) and also waits for PageWriteback bits. Thus we
172 : * cannot get to ext4_ext_truncate() before all IOs overlapping that range are
173 : * completed (happens from ext4_free_ioend()).
174 : */
175 0 : static int ext4_end_io_end(ext4_io_end_t *io_end)
176 : {
177 0 : struct inode *inode = io_end->inode;
178 0 : handle_t *handle = io_end->handle;
179 0 : int ret = 0;
180 :
181 0 : ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p,"
182 : "list->prev 0x%p\n",
183 : io_end, inode->i_ino, io_end->list.next, io_end->list.prev);
184 :
185 0 : io_end->handle = NULL; /* Following call will use up the handle */
186 0 : ret = ext4_convert_unwritten_io_end_vec(handle, io_end);
187 0 : if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) {
188 0 : ext4_msg(inode->i_sb, KERN_EMERG,
189 : "failed to convert unwritten extents to written "
190 : "extents -- potential data loss! "
191 : "(inode %lu, error %d)", inode->i_ino, ret);
192 : }
193 0 : ext4_clear_io_unwritten_flag(io_end);
194 0 : ext4_release_io_end(io_end);
195 0 : return ret;
196 : }
197 :
198 : static void dump_completed_IO(struct inode *inode, struct list_head *head)
199 : {
200 : #ifdef EXT4FS_DEBUG
201 : struct list_head *cur, *before, *after;
202 : ext4_io_end_t *io_end, *io_end0, *io_end1;
203 :
204 : if (list_empty(head))
205 : return;
206 :
207 : ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
208 : list_for_each_entry(io_end, head, list) {
209 : cur = &io_end->list;
210 : before = cur->prev;
211 : io_end0 = container_of(before, ext4_io_end_t, list);
212 : after = cur->next;
213 : io_end1 = container_of(after, ext4_io_end_t, list);
214 :
215 : ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
216 : io_end, inode->i_ino, io_end0, io_end1);
217 : }
218 : #endif
219 : }
220 :
221 : /* Add the io_end to per-inode completed end_io list. */
222 0 : static void ext4_add_complete_io(ext4_io_end_t *io_end)
223 : {
224 0 : struct ext4_inode_info *ei = EXT4_I(io_end->inode);
225 0 : struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
226 0 : struct workqueue_struct *wq;
227 0 : unsigned long flags;
228 :
229 : /* Only reserved conversions from writeback should enter here */
230 0 : WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
231 0 : WARN_ON(!io_end->handle && sbi->s_journal);
232 0 : spin_lock_irqsave(&ei->i_completed_io_lock, flags);
233 0 : wq = sbi->rsv_conversion_wq;
234 0 : if (list_empty(&ei->i_rsv_conversion_list))
235 0 : queue_work(wq, &ei->i_rsv_conversion_work);
236 0 : list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
237 0 : spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
238 0 : }
239 :
240 0 : static int ext4_do_flush_completed_IO(struct inode *inode,
241 : struct list_head *head)
242 : {
243 0 : ext4_io_end_t *io_end;
244 0 : struct list_head unwritten;
245 0 : unsigned long flags;
246 0 : struct ext4_inode_info *ei = EXT4_I(inode);
247 0 : int err, ret = 0;
248 :
249 0 : spin_lock_irqsave(&ei->i_completed_io_lock, flags);
250 0 : dump_completed_IO(inode, head);
251 0 : list_replace_init(head, &unwritten);
252 0 : spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
253 :
254 0 : while (!list_empty(&unwritten)) {
255 0 : io_end = list_entry(unwritten.next, ext4_io_end_t, list);
256 0 : BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
257 0 : list_del_init(&io_end->list);
258 :
259 0 : err = ext4_end_io_end(io_end);
260 0 : if (unlikely(!ret && err))
261 0 : ret = err;
262 : }
263 0 : return ret;
264 : }
265 :
266 : /*
267 : * work on completed IO, to convert unwritten extents to extents
268 : */
269 0 : void ext4_end_io_rsv_work(struct work_struct *work)
270 : {
271 0 : struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
272 : i_rsv_conversion_work);
273 0 : ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
274 0 : }
275 :
276 0 : ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
277 : {
278 0 : ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags);
279 :
280 0 : if (io_end) {
281 0 : io_end->inode = inode;
282 0 : INIT_LIST_HEAD(&io_end->list);
283 0 : INIT_LIST_HEAD(&io_end->list_vec);
284 0 : refcount_set(&io_end->count, 1);
285 : }
286 0 : return io_end;
287 : }
288 :
289 0 : void ext4_put_io_end_defer(ext4_io_end_t *io_end)
290 : {
291 0 : if (refcount_dec_and_test(&io_end->count)) {
292 0 : if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) ||
293 0 : list_empty(&io_end->list_vec)) {
294 0 : ext4_release_io_end(io_end);
295 0 : return;
296 : }
297 0 : ext4_add_complete_io(io_end);
298 : }
299 : }
300 :
301 0 : int ext4_put_io_end(ext4_io_end_t *io_end)
302 : {
303 0 : int err = 0;
304 :
305 0 : if (refcount_dec_and_test(&io_end->count)) {
306 0 : if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
307 0 : err = ext4_convert_unwritten_io_end_vec(io_end->handle,
308 : io_end);
309 0 : io_end->handle = NULL;
310 0 : ext4_clear_io_unwritten_flag(io_end);
311 : }
312 0 : ext4_release_io_end(io_end);
313 : }
314 0 : return err;
315 : }
316 :
317 0 : ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
318 : {
319 0 : refcount_inc(&io_end->count);
320 0 : return io_end;
321 : }
322 :
323 : /* BIO completion function for page writeback */
324 0 : static void ext4_end_bio(struct bio *bio)
325 : {
326 0 : ext4_io_end_t *io_end = bio->bi_private;
327 0 : sector_t bi_sector = bio->bi_iter.bi_sector;
328 :
329 0 : if (WARN_ONCE(!io_end, "io_end is NULL: %pg: sector %Lu len %u err %d\n",
330 : bio->bi_bdev,
331 : (long long) bio->bi_iter.bi_sector,
332 : (unsigned) bio_sectors(bio),
333 : bio->bi_status)) {
334 0 : ext4_finish_bio(bio);
335 0 : bio_put(bio);
336 0 : return;
337 : }
338 0 : bio->bi_end_io = NULL;
339 :
340 0 : if (bio->bi_status) {
341 0 : struct inode *inode = io_end->inode;
342 :
343 0 : ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
344 : "starting block %llu)",
345 : bio->bi_status, inode->i_ino,
346 : (unsigned long long)
347 : bi_sector >> (inode->i_blkbits - 9));
348 0 : mapping_set_error(inode->i_mapping,
349 : blk_status_to_errno(bio->bi_status));
350 : }
351 :
352 0 : if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
353 : /*
354 : * Link bio into list hanging from io_end. We have to do it
355 : * atomically as bio completions can be racing against each
356 : * other.
357 : */
358 0 : bio->bi_private = xchg(&io_end->bio, bio);
359 0 : ext4_put_io_end_defer(io_end);
360 : } else {
361 : /*
362 : * Drop io_end reference early. Inode can get freed once
363 : * we finish the bio.
364 : */
365 0 : ext4_put_io_end_defer(io_end);
366 0 : ext4_finish_bio(bio);
367 0 : bio_put(bio);
368 : }
369 : }
370 :
371 0 : void ext4_io_submit(struct ext4_io_submit *io)
372 : {
373 0 : struct bio *bio = io->io_bio;
374 :
375 0 : if (bio) {
376 0 : if (io->io_wbc->sync_mode == WB_SYNC_ALL)
377 0 : io->io_bio->bi_opf |= REQ_SYNC;
378 0 : submit_bio(io->io_bio);
379 : }
380 0 : io->io_bio = NULL;
381 0 : }
382 :
383 0 : void ext4_io_submit_init(struct ext4_io_submit *io,
384 : struct writeback_control *wbc)
385 : {
386 0 : io->io_wbc = wbc;
387 0 : io->io_bio = NULL;
388 0 : io->io_end = NULL;
389 0 : }
390 :
391 0 : static void io_submit_init_bio(struct ext4_io_submit *io,
392 : struct buffer_head *bh)
393 : {
394 0 : struct bio *bio;
395 :
396 : /*
397 : * bio_alloc will _always_ be able to allocate a bio if
398 : * __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset().
399 : */
400 0 : bio = bio_alloc(bh->b_bdev, BIO_MAX_VECS, REQ_OP_WRITE, GFP_NOIO);
401 0 : fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
402 0 : bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
403 0 : bio->bi_end_io = ext4_end_bio;
404 0 : bio->bi_private = ext4_get_io_end(io->io_end);
405 0 : io->io_bio = bio;
406 0 : io->io_next_block = bh->b_blocknr;
407 0 : wbc_init_bio(io->io_wbc, bio);
408 0 : }
409 :
410 0 : static void io_submit_add_bh(struct ext4_io_submit *io,
411 : struct inode *inode,
412 : struct folio *folio,
413 : struct folio *io_folio,
414 : struct buffer_head *bh)
415 : {
416 0 : if (io->io_bio && (bh->b_blocknr != io->io_next_block ||
417 : !fscrypt_mergeable_bio_bh(io->io_bio, bh))) {
418 0 : submit_and_retry:
419 0 : ext4_io_submit(io);
420 : }
421 0 : if (io->io_bio == NULL)
422 0 : io_submit_init_bio(io, bh);
423 0 : if (!bio_add_folio(io->io_bio, io_folio, bh->b_size, bh_offset(bh)))
424 0 : goto submit_and_retry;
425 0 : wbc_account_cgroup_owner(io->io_wbc, &folio->page, bh->b_size);
426 0 : io->io_next_block++;
427 0 : }
428 :
429 0 : int ext4_bio_write_folio(struct ext4_io_submit *io, struct folio *folio,
430 : size_t len)
431 : {
432 0 : struct folio *io_folio = folio;
433 0 : struct inode *inode = folio->mapping->host;
434 0 : unsigned block_start;
435 0 : struct buffer_head *bh, *head;
436 0 : int ret = 0;
437 0 : int nr_to_submit = 0;
438 0 : struct writeback_control *wbc = io->io_wbc;
439 0 : bool keep_towrite = false;
440 :
441 0 : BUG_ON(!folio_test_locked(folio));
442 0 : BUG_ON(folio_test_writeback(folio));
443 :
444 0 : folio_clear_error(folio);
445 :
446 : /*
447 : * Comments copied from block_write_full_page:
448 : *
449 : * The folio straddles i_size. It must be zeroed out on each and every
450 : * writepage invocation because it may be mmapped. "A file is mapped
451 : * in multiples of the page size. For a file that is not a multiple of
452 : * the page size, the remaining memory is zeroed when mapped, and
453 : * writes to that region are not written out to the file."
454 : */
455 0 : if (len < folio_size(folio))
456 0 : folio_zero_segment(folio, len, folio_size(folio));
457 : /*
458 : * In the first loop we prepare and mark buffers to submit. We have to
459 : * mark all buffers in the folio before submitting so that
460 : * folio_end_writeback() cannot be called from ext4_end_bio() when IO
461 : * on the first buffer finishes and we are still working on submitting
462 : * the second buffer.
463 : */
464 0 : bh = head = folio_buffers(folio);
465 0 : do {
466 0 : block_start = bh_offset(bh);
467 0 : if (block_start >= len) {
468 0 : clear_buffer_dirty(bh);
469 0 : set_buffer_uptodate(bh);
470 0 : continue;
471 : }
472 0 : if (!buffer_dirty(bh) || buffer_delay(bh) ||
473 0 : !buffer_mapped(bh) || buffer_unwritten(bh)) {
474 : /* A hole? We can safely clear the dirty bit */
475 0 : if (!buffer_mapped(bh))
476 0 : clear_buffer_dirty(bh);
477 : /*
478 : * Keeping dirty some buffer we cannot write? Make sure
479 : * to redirty the folio and keep TOWRITE tag so that
480 : * racing WB_SYNC_ALL writeback does not skip the folio.
481 : * This happens e.g. when doing writeout for
482 : * transaction commit or when journalled data is not
483 : * yet committed.
484 : */
485 0 : if (buffer_dirty(bh) ||
486 0 : (buffer_jbd(bh) && buffer_jbddirty(bh))) {
487 0 : if (!folio_test_dirty(folio))
488 0 : folio_redirty_for_writepage(wbc, folio);
489 : keep_towrite = true;
490 : }
491 0 : continue;
492 : }
493 0 : if (buffer_new(bh))
494 0 : clear_buffer_new(bh);
495 0 : set_buffer_async_write(bh);
496 0 : clear_buffer_dirty(bh);
497 0 : nr_to_submit++;
498 0 : } while ((bh = bh->b_this_page) != head);
499 :
500 : /* Nothing to submit? Just unlock the folio... */
501 0 : if (!nr_to_submit)
502 : return 0;
503 :
504 0 : bh = head = folio_buffers(folio);
505 :
506 : /*
507 : * If any blocks are being written to an encrypted file, encrypt them
508 : * into a bounce page. For simplicity, just encrypt until the last
509 : * block which might be needed. This may cause some unneeded blocks
510 : * (e.g. holes) to be unnecessarily encrypted, but this is rare and
511 : * can't happen in the common case of blocksize == PAGE_SIZE.
512 : */
513 0 : if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
514 : gfp_t gfp_flags = GFP_NOFS;
515 : unsigned int enc_bytes = round_up(len, i_blocksize(inode));
516 : struct page *bounce_page;
517 :
518 : /*
519 : * Since bounce page allocation uses a mempool, we can only use
520 : * a waiting mask (i.e. request guaranteed allocation) on the
521 : * first page of the bio. Otherwise it can deadlock.
522 : */
523 : if (io->io_bio)
524 : gfp_flags = GFP_NOWAIT | __GFP_NOWARN;
525 : retry_encrypt:
526 : bounce_page = fscrypt_encrypt_pagecache_blocks(&folio->page,
527 : enc_bytes, 0, gfp_flags);
528 : if (IS_ERR(bounce_page)) {
529 : ret = PTR_ERR(bounce_page);
530 : if (ret == -ENOMEM &&
531 : (io->io_bio || wbc->sync_mode == WB_SYNC_ALL)) {
532 : gfp_t new_gfp_flags = GFP_NOFS;
533 : if (io->io_bio)
534 : ext4_io_submit(io);
535 : else
536 : new_gfp_flags |= __GFP_NOFAIL;
537 : memalloc_retry_wait(gfp_flags);
538 : gfp_flags = new_gfp_flags;
539 : goto retry_encrypt;
540 : }
541 :
542 : printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
543 : folio_redirty_for_writepage(wbc, folio);
544 : do {
545 : if (buffer_async_write(bh)) {
546 : clear_buffer_async_write(bh);
547 : set_buffer_dirty(bh);
548 : }
549 : bh = bh->b_this_page;
550 : } while (bh != head);
551 :
552 : return ret;
553 : }
554 : io_folio = page_folio(bounce_page);
555 : }
556 :
557 0 : __folio_start_writeback(folio, keep_towrite);
558 :
559 : /* Now submit buffers to write */
560 0 : do {
561 0 : if (!buffer_async_write(bh))
562 0 : continue;
563 0 : io_submit_add_bh(io, inode, folio, io_folio, bh);
564 0 : } while ((bh = bh->b_this_page) != head);
565 :
566 : return 0;
567 : }
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