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/backing-dev.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 1 : int __init ext4_init_pageio(void)
37 : {
38 1 : io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
39 1 : if (io_end_cachep == NULL)
40 : return -ENOMEM;
41 :
42 1 : io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0);
43 1 : 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 70 : struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end)
57 : {
58 70 : struct ext4_io_end_vec *io_end_vec;
59 :
60 70 : io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS);
61 70 : if (!io_end_vec)
62 70 : return ERR_PTR(-ENOMEM);
63 70 : INIT_LIST_HEAD(&io_end_vec->list);
64 70 : list_add_tail(&io_end_vec->list, &io_end->list_vec);
65 70 : return io_end_vec;
66 : }
67 :
68 154 : static void ext4_free_io_end_vec(ext4_io_end_t *io_end)
69 : {
70 154 : struct ext4_io_end_vec *io_end_vec, *tmp;
71 :
72 154 : if (list_empty(&io_end->list_vec))
73 : return;
74 140 : list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) {
75 70 : list_del(&io_end_vec->list);
76 70 : kmem_cache_free(io_end_vec_cachep, io_end_vec);
77 : }
78 : }
79 :
80 348 : struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end)
81 : {
82 348 : BUG_ON(list_empty(&io_end->list_vec));
83 348 : 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 :
100 116 : static void ext4_finish_bio(struct bio *bio)
101 : {
102 116 : struct bio_vec *bvec;
103 116 : struct bvec_iter_all iter_all;
104 :
105 746 : bio_for_each_segment_all(bvec, bio, iter_all) {
106 514 : struct page *page = bvec->bv_page;
107 514 : struct page *bounce_page = NULL;
108 514 : struct buffer_head *bh, *head;
109 514 : unsigned bio_start = bvec->bv_offset;
110 514 : unsigned bio_end = bio_start + bvec->bv_len;
111 514 : unsigned under_io = 0;
112 514 : unsigned long flags;
113 :
114 514 : if (fscrypt_is_bounce_page(page)) {
115 : bounce_page = page;
116 : page = fscrypt_pagecache_page(bounce_page);
117 : }
118 :
119 514 : if (bio->bi_status) {
120 0 : SetPageError(page);
121 0 : mapping_set_error(page->mapping, -EIO);
122 : }
123 514 : bh = head = page_buffers(page);
124 : /*
125 : * We check all buffers in the page under b_uptodate_lock
126 : * to avoid races with other end io clearing async_write flags
127 : */
128 514 : spin_lock_irqsave(&head->b_uptodate_lock, flags);
129 514 : do {
130 514 : if (bh_offset(bh) < bio_start ||
131 514 : bh_offset(bh) + bh->b_size > bio_end) {
132 0 : if (buffer_async_write(bh))
133 0 : under_io++;
134 0 : continue;
135 : }
136 514 : clear_buffer_async_write(bh);
137 514 : if (bio->bi_status)
138 0 : buffer_io_error(bh);
139 514 : } while ((bh = bh->b_this_page) != head);
140 514 : spin_unlock_irqrestore(&head->b_uptodate_lock, flags);
141 514 : if (!under_io) {
142 514 : fscrypt_free_bounce_page(bounce_page);
143 514 : end_page_writeback(page);
144 : }
145 : }
146 116 : }
147 :
148 154 : static void ext4_release_io_end(ext4_io_end_t *io_end)
149 : {
150 154 : struct bio *bio, *next_bio;
151 :
152 154 : BUG_ON(!list_empty(&io_end->list));
153 154 : BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
154 154 : WARN_ON(io_end->handle);
155 :
156 224 : for (bio = io_end->bio; bio; bio = next_bio) {
157 70 : next_bio = bio->bi_private;
158 70 : ext4_finish_bio(bio);
159 70 : bio_put(bio);
160 : }
161 154 : ext4_free_io_end_vec(io_end);
162 154 : kmem_cache_free(io_end_cachep, io_end);
163 154 : }
164 :
165 : /*
166 : * Check a range of space and convert unwritten extents to written. Note that
167 : * we are protected from truncate touching same part of extent tree by the
168 : * fact that truncate code waits for all DIO to finish (thus exclusion from
169 : * direct IO is achieved) and also waits for PageWriteback bits. Thus we
170 : * cannot get to ext4_ext_truncate() before all IOs overlapping that range are
171 : * completed (happens from ext4_free_ioend()).
172 : */
173 70 : static int ext4_end_io_end(ext4_io_end_t *io_end)
174 : {
175 70 : struct inode *inode = io_end->inode;
176 70 : handle_t *handle = io_end->handle;
177 70 : int ret = 0;
178 :
179 70 : ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p,"
180 : "list->prev 0x%p\n",
181 : io_end, inode->i_ino, io_end->list.next, io_end->list.prev);
182 :
183 70 : io_end->handle = NULL; /* Following call will use up the handle */
184 70 : ret = ext4_convert_unwritten_io_end_vec(handle, io_end);
185 70 : if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) {
186 0 : ext4_msg(inode->i_sb, KERN_EMERG,
187 : "failed to convert unwritten extents to written "
188 : "extents -- potential data loss! "
189 : "(inode %lu, error %d)", inode->i_ino, ret);
190 : }
191 70 : ext4_clear_io_unwritten_flag(io_end);
192 70 : ext4_release_io_end(io_end);
193 70 : return ret;
194 : }
195 :
196 64 : static void dump_completed_IO(struct inode *inode, struct list_head *head)
197 : {
198 : #ifdef EXT4FS_DEBUG
199 : struct list_head *cur, *before, *after;
200 : ext4_io_end_t *io_end, *io_end0, *io_end1;
201 :
202 : if (list_empty(head))
203 : return;
204 :
205 : ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
206 : list_for_each_entry(io_end, head, list) {
207 : cur = &io_end->list;
208 : before = cur->prev;
209 : io_end0 = container_of(before, ext4_io_end_t, list);
210 : after = cur->next;
211 : io_end1 = container_of(after, ext4_io_end_t, list);
212 :
213 : ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
214 : io_end, inode->i_ino, io_end0, io_end1);
215 : }
216 : #endif
217 64 : }
218 :
219 : /* Add the io_end to per-inode completed end_io list. */
220 70 : static void ext4_add_complete_io(ext4_io_end_t *io_end)
221 : {
222 70 : struct ext4_inode_info *ei = EXT4_I(io_end->inode);
223 70 : struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
224 70 : struct workqueue_struct *wq;
225 70 : unsigned long flags;
226 :
227 : /* Only reserved conversions from writeback should enter here */
228 70 : WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
229 140 : WARN_ON(!io_end->handle && sbi->s_journal);
230 70 : spin_lock_irqsave(&ei->i_completed_io_lock, flags);
231 70 : wq = sbi->rsv_conversion_wq;
232 70 : if (list_empty(&ei->i_rsv_conversion_list))
233 64 : queue_work(wq, &ei->i_rsv_conversion_work);
234 70 : list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
235 70 : spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
236 70 : }
237 :
238 64 : static int ext4_do_flush_completed_IO(struct inode *inode,
239 : struct list_head *head)
240 : {
241 64 : ext4_io_end_t *io_end;
242 64 : struct list_head unwritten;
243 64 : unsigned long flags;
244 64 : struct ext4_inode_info *ei = EXT4_I(inode);
245 64 : int err, ret = 0;
246 :
247 64 : spin_lock_irqsave(&ei->i_completed_io_lock, flags);
248 64 : dump_completed_IO(inode, head);
249 64 : list_replace_init(head, &unwritten);
250 64 : spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
251 :
252 134 : while (!list_empty(&unwritten)) {
253 70 : io_end = list_entry(unwritten.next, ext4_io_end_t, list);
254 70 : BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
255 70 : list_del_init(&io_end->list);
256 :
257 70 : err = ext4_end_io_end(io_end);
258 70 : if (unlikely(!ret && err))
259 0 : ret = err;
260 : }
261 64 : return ret;
262 : }
263 :
264 : /*
265 : * work on completed IO, to convert unwritten extents to extents
266 : */
267 64 : void ext4_end_io_rsv_work(struct work_struct *work)
268 : {
269 64 : struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
270 : i_rsv_conversion_work);
271 64 : ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
272 64 : }
273 :
274 154 : ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
275 : {
276 154 : ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags);
277 :
278 154 : if (io_end) {
279 154 : io_end->inode = inode;
280 154 : INIT_LIST_HEAD(&io_end->list);
281 154 : INIT_LIST_HEAD(&io_end->list_vec);
282 154 : atomic_set(&io_end->count, 1);
283 : }
284 154 : return io_end;
285 : }
286 :
287 200 : void ext4_put_io_end_defer(ext4_io_end_t *io_end)
288 : {
289 400 : if (atomic_dec_and_test(&io_end->count)) {
290 154 : if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) ||
291 70 : list_empty(&io_end->list_vec)) {
292 84 : ext4_release_io_end(io_end);
293 84 : return;
294 : }
295 70 : ext4_add_complete_io(io_end);
296 : }
297 : }
298 :
299 70 : int ext4_put_io_end(ext4_io_end_t *io_end)
300 : {
301 70 : int err = 0;
302 :
303 140 : if (atomic_dec_and_test(&io_end->count)) {
304 0 : if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
305 0 : err = ext4_convert_unwritten_io_end_vec(io_end->handle,
306 : io_end);
307 0 : io_end->handle = NULL;
308 0 : ext4_clear_io_unwritten_flag(io_end);
309 : }
310 0 : ext4_release_io_end(io_end);
311 : }
312 70 : return err;
313 : }
314 :
315 116 : ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
316 : {
317 116 : atomic_inc(&io_end->count);
318 116 : return io_end;
319 : }
320 :
321 : /* BIO completion function for page writeback */
322 116 : static void ext4_end_bio(struct bio *bio)
323 : {
324 116 : ext4_io_end_t *io_end = bio->bi_private;
325 116 : sector_t bi_sector = bio->bi_iter.bi_sector;
326 116 : char b[BDEVNAME_SIZE];
327 :
328 116 : if (WARN_ONCE(!io_end, "io_end is NULL: %s: sector %Lu len %u err %d\n",
329 : bio_devname(bio, b),
330 : (long long) bio->bi_iter.bi_sector,
331 : (unsigned) bio_sectors(bio),
332 : bio->bi_status)) {
333 0 : ext4_finish_bio(bio);
334 0 : bio_put(bio);
335 0 : return;
336 : }
337 116 : bio->bi_end_io = NULL;
338 :
339 116 : if (bio->bi_status) {
340 0 : struct inode *inode = io_end->inode;
341 :
342 0 : ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
343 : "starting block %llu)",
344 : bio->bi_status, inode->i_ino,
345 : (unsigned long long)
346 : bi_sector >> (inode->i_blkbits - 9));
347 0 : mapping_set_error(inode->i_mapping,
348 0 : blk_status_to_errno(bio->bi_status));
349 : }
350 :
351 116 : if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
352 : /*
353 : * Link bio into list hanging from io_end. We have to do it
354 : * atomically as bio completions can be racing against each
355 : * other.
356 : */
357 70 : bio->bi_private = xchg(&io_end->bio, bio);
358 70 : ext4_put_io_end_defer(io_end);
359 : } else {
360 : /*
361 : * Drop io_end reference early. Inode can get freed once
362 : * we finish the bio.
363 : */
364 46 : ext4_put_io_end_defer(io_end);
365 46 : ext4_finish_bio(bio);
366 46 : bio_put(bio);
367 : }
368 : }
369 :
370 164 : void ext4_io_submit(struct ext4_io_submit *io)
371 : {
372 164 : struct bio *bio = io->io_bio;
373 :
374 164 : if (bio) {
375 116 : int io_op_flags = io->io_wbc->sync_mode == WB_SYNC_ALL ?
376 : REQ_SYNC : 0;
377 116 : io->io_bio->bi_write_hint = io->io_end->inode->i_write_hint;
378 116 : bio_set_op_attrs(io->io_bio, REQ_OP_WRITE, io_op_flags);
379 116 : submit_bio(io->io_bio);
380 : }
381 164 : io->io_bio = NULL;
382 164 : }
383 :
384 84 : void ext4_io_submit_init(struct ext4_io_submit *io,
385 : struct writeback_control *wbc)
386 : {
387 84 : io->io_wbc = wbc;
388 84 : io->io_bio = NULL;
389 84 : io->io_end = NULL;
390 84 : }
391 :
392 116 : static void io_submit_init_bio(struct ext4_io_submit *io,
393 : struct buffer_head *bh)
394 : {
395 116 : struct bio *bio;
396 :
397 : /*
398 : * bio_alloc will _always_ be able to allocate a bio if
399 : * __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset().
400 : */
401 116 : bio = bio_alloc(GFP_NOIO, BIO_MAX_VECS);
402 116 : fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
403 116 : bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
404 116 : bio_set_dev(bio, bh->b_bdev);
405 116 : bio->bi_end_io = ext4_end_bio;
406 116 : bio->bi_private = ext4_get_io_end(io->io_end);
407 116 : io->io_bio = bio;
408 116 : io->io_next_block = bh->b_blocknr;
409 116 : wbc_init_bio(io->io_wbc, bio);
410 116 : }
411 :
412 514 : static void io_submit_add_bh(struct ext4_io_submit *io,
413 : struct inode *inode,
414 : struct page *page,
415 : struct buffer_head *bh)
416 : {
417 514 : int ret;
418 :
419 514 : if (io->io_bio && (bh->b_blocknr != io->io_next_block ||
420 514 : !fscrypt_mergeable_bio_bh(io->io_bio, bh))) {
421 10 : submit_and_retry:
422 10 : ext4_io_submit(io);
423 : }
424 514 : if (io->io_bio == NULL) {
425 116 : io_submit_init_bio(io, bh);
426 116 : io->io_bio->bi_write_hint = inode->i_write_hint;
427 : }
428 514 : ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
429 514 : if (ret != bh->b_size)
430 0 : goto submit_and_retry;
431 514 : wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size);
432 514 : io->io_next_block++;
433 514 : }
434 :
435 514 : int ext4_bio_write_page(struct ext4_io_submit *io,
436 : struct page *page,
437 : int len,
438 : bool keep_towrite)
439 : {
440 514 : struct page *bounce_page = NULL;
441 514 : struct inode *inode = page->mapping->host;
442 514 : unsigned block_start;
443 514 : struct buffer_head *bh, *head;
444 514 : int ret = 0;
445 514 : int nr_submitted = 0;
446 514 : int nr_to_submit = 0;
447 514 : struct writeback_control *wbc = io->io_wbc;
448 :
449 1028 : BUG_ON(!PageLocked(page));
450 1028 : BUG_ON(PageWriteback(page));
451 :
452 514 : if (keep_towrite)
453 0 : set_page_writeback_keepwrite(page);
454 : else
455 514 : set_page_writeback(page);
456 514 : ClearPageError(page);
457 :
458 : /*
459 : * Comments copied from block_write_full_page:
460 : *
461 : * The page straddles i_size. It must be zeroed out on each and every
462 : * writepage invocation because it may be mmapped. "A file is mapped
463 : * in multiples of the page size. For a file that is not a multiple of
464 : * the page size, the remaining memory is zeroed when mapped, and
465 : * writes to that region are not written out to the file."
466 : */
467 514 : if (len < PAGE_SIZE)
468 29 : zero_user_segment(page, len, PAGE_SIZE);
469 : /*
470 : * In the first loop we prepare and mark buffers to submit. We have to
471 : * mark all buffers in the page before submitting so that
472 : * end_page_writeback() cannot be called from ext4_bio_end_io() when IO
473 : * on the first buffer finishes and we are still working on submitting
474 : * the second buffer.
475 : */
476 514 : bh = head = page_buffers(page);
477 514 : do {
478 514 : block_start = bh_offset(bh);
479 514 : if (block_start >= len) {
480 0 : clear_buffer_dirty(bh);
481 0 : set_buffer_uptodate(bh);
482 0 : continue;
483 : }
484 1028 : if (!buffer_dirty(bh) || buffer_delay(bh) ||
485 1028 : !buffer_mapped(bh) || buffer_unwritten(bh)) {
486 : /* A hole? We can safely clear the dirty bit */
487 0 : if (!buffer_mapped(bh))
488 0 : clear_buffer_dirty(bh);
489 0 : if (io->io_bio)
490 0 : ext4_io_submit(io);
491 0 : continue;
492 : }
493 514 : if (buffer_new(bh))
494 0 : clear_buffer_new(bh);
495 514 : set_buffer_async_write(bh);
496 514 : nr_to_submit++;
497 514 : } while ((bh = bh->b_this_page) != head);
498 :
499 514 : bh = head = page_buffers(page);
500 :
501 : /*
502 : * If any blocks are being written to an encrypted file, encrypt them
503 : * into a bounce page. For simplicity, just encrypt until the last
504 : * block which might be needed. This may cause some unneeded blocks
505 : * (e.g. holes) to be unnecessarily encrypted, but this is rare and
506 : * can't happen in the common case of blocksize == PAGE_SIZE.
507 : */
508 514 : if (fscrypt_inode_uses_fs_layer_crypto(inode) && nr_to_submit) {
509 : gfp_t gfp_flags = GFP_NOFS;
510 : unsigned int enc_bytes = round_up(len, i_blocksize(inode));
511 :
512 : /*
513 : * Since bounce page allocation uses a mempool, we can only use
514 : * a waiting mask (i.e. request guaranteed allocation) on the
515 : * first page of the bio. Otherwise it can deadlock.
516 : */
517 : if (io->io_bio)
518 : gfp_flags = GFP_NOWAIT | __GFP_NOWARN;
519 : retry_encrypt:
520 : bounce_page = fscrypt_encrypt_pagecache_blocks(page, enc_bytes,
521 : 0, gfp_flags);
522 : if (IS_ERR(bounce_page)) {
523 : ret = PTR_ERR(bounce_page);
524 : if (ret == -ENOMEM &&
525 : (io->io_bio || wbc->sync_mode == WB_SYNC_ALL)) {
526 : gfp_flags = GFP_NOFS;
527 : if (io->io_bio)
528 : ext4_io_submit(io);
529 : else
530 : gfp_flags |= __GFP_NOFAIL;
531 : congestion_wait(BLK_RW_ASYNC, HZ/50);
532 : goto retry_encrypt;
533 : }
534 :
535 : printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
536 : redirty_page_for_writepage(wbc, page);
537 : do {
538 : clear_buffer_async_write(bh);
539 : bh = bh->b_this_page;
540 : } while (bh != head);
541 : goto unlock;
542 : }
543 : }
544 :
545 : /* Now submit buffers to write */
546 514 : do {
547 514 : if (!buffer_async_write(bh))
548 0 : continue;
549 514 : io_submit_add_bh(io, inode,
550 : bounce_page ? bounce_page : page, bh);
551 514 : nr_submitted++;
552 514 : clear_buffer_dirty(bh);
553 514 : } while ((bh = bh->b_this_page) != head);
554 :
555 514 : unlock:
556 514 : unlock_page(page);
557 : /* Nothing submitted - we have to end page writeback */
558 514 : if (!nr_submitted)
559 0 : end_page_writeback(page);
560 514 : return ret;
561 : }
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