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1/*
2 * linux/fs/ext4/page-io.c
3 *
4 * This contains the new page_io functions for ext4
5 *
6 * Written by Theodore Ts'o, 2010.
7 */
8
9#include <linux/fs.h>
10#include <linux/time.h>
11#include <linux/highuid.h>
12#include <linux/pagemap.h>
13#include <linux/quotaops.h>
14#include <linux/string.h>
15#include <linux/buffer_head.h>
16#include <linux/writeback.h>
17#include <linux/pagevec.h>
18#include <linux/mpage.h>
19#include <linux/namei.h>
20#include <linux/uio.h>
21#include <linux/bio.h>
22#include <linux/workqueue.h>
23#include <linux/kernel.h>
24#include <linux/slab.h>
25#include <linux/mm.h>
26#include <linux/backing-dev.h>
27#include <linux/fscrypto.h>
28
29#include "ext4_jbd2.h"
30#include "xattr.h"
31#include "acl.h"
32
33static struct kmem_cache *io_end_cachep;
34
35int __init ext4_init_pageio(void)
36{
37 io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
38 if (io_end_cachep == NULL)
39 return -ENOMEM;
40 return 0;
41}
42
43void ext4_exit_pageio(void)
44{
45 kmem_cache_destroy(io_end_cachep);
46}
47
48/*
49 * Print an buffer I/O error compatible with the fs/buffer.c. This
50 * provides compatibility with dmesg scrapers that look for a specific
51 * buffer I/O error message. We really need a unified error reporting
52 * structure to userspace ala Digital Unix's uerf system, but it's
53 * probably not going to happen in my lifetime, due to LKML politics...
54 */
55static void buffer_io_error(struct buffer_head *bh)
56{
57 printk_ratelimited(KERN_ERR "Buffer I/O error on device %pg, logical block %llu\n",
58 bh->b_bdev,
59 (unsigned long long)bh->b_blocknr);
60}
61
62static void ext4_finish_bio(struct bio *bio)
63{
64 int i;
65 struct bio_vec *bvec;
66
67 bio_for_each_segment_all(bvec, bio, i) {
68 struct page *page = bvec->bv_page;
69#ifdef CONFIG_EXT4_FS_ENCRYPTION
70 struct page *data_page = NULL;
71#endif
72 struct buffer_head *bh, *head;
73 unsigned bio_start = bvec->bv_offset;
74 unsigned bio_end = bio_start + bvec->bv_len;
75 unsigned under_io = 0;
76 unsigned long flags;
77
78 if (!page)
79 continue;
80
81#ifdef CONFIG_EXT4_FS_ENCRYPTION
82 if (!page->mapping) {
83 /* The bounce data pages are unmapped. */
84 data_page = page;
85 fscrypt_pullback_bio_page(&page, false);
86 }
87#endif
88
89 if (bio->bi_error) {
90 SetPageError(page);
91 mapping_set_error(page->mapping, -EIO);
92 }
93 bh = head = page_buffers(page);
94 /*
95 * We check all buffers in the page under BH_Uptodate_Lock
96 * to avoid races with other end io clearing async_write flags
97 */
98 local_irq_save(flags);
99 bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
100 do {
101 if (bh_offset(bh) < bio_start ||
102 bh_offset(bh) + bh->b_size > bio_end) {
103 if (buffer_async_write(bh))
104 under_io++;
105 continue;
106 }
107 clear_buffer_async_write(bh);
108 if (bio->bi_error)
109 buffer_io_error(bh);
110 } while ((bh = bh->b_this_page) != head);
111 bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
112 local_irq_restore(flags);
113 if (!under_io) {
114#ifdef CONFIG_EXT4_FS_ENCRYPTION
115 if (data_page)
116 fscrypt_restore_control_page(data_page);
117#endif
118 end_page_writeback(page);
119 }
120 }
121}
122
123static void ext4_release_io_end(ext4_io_end_t *io_end)
124{
125 struct bio *bio, *next_bio;
126
127 BUG_ON(!list_empty(&io_end->list));
128 BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
129 WARN_ON(io_end->handle);
130
131 for (bio = io_end->bio; bio; bio = next_bio) {
132 next_bio = bio->bi_private;
133 ext4_finish_bio(bio);
134 bio_put(bio);
135 }
136 kmem_cache_free(io_end_cachep, io_end);
137}
138
139/*
140 * Check a range of space and convert unwritten extents to written. Note that
141 * we are protected from truncate touching same part of extent tree by the
142 * fact that truncate code waits for all DIO to finish (thus exclusion from
143 * direct IO is achieved) and also waits for PageWriteback bits. Thus we
144 * cannot get to ext4_ext_truncate() before all IOs overlapping that range are
145 * completed (happens from ext4_free_ioend()).
146 */
147static int ext4_end_io(ext4_io_end_t *io)
148{
149 struct inode *inode = io->inode;
150 loff_t offset = io->offset;
151 ssize_t size = io->size;
152 handle_t *handle = io->handle;
153 int ret = 0;
154
155 ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
156 "list->prev 0x%p\n",
157 io, inode->i_ino, io->list.next, io->list.prev);
158
159 io->handle = NULL; /* Following call will use up the handle */
160 ret = ext4_convert_unwritten_extents(handle, inode, offset, size);
161 if (ret < 0) {
162 ext4_msg(inode->i_sb, KERN_EMERG,
163 "failed to convert unwritten extents to written "
164 "extents -- potential data loss! "
165 "(inode %lu, offset %llu, size %zd, error %d)",
166 inode->i_ino, offset, size, ret);
167 }
168 ext4_clear_io_unwritten_flag(io);
169 ext4_release_io_end(io);
170 return ret;
171}
172
173static void dump_completed_IO(struct inode *inode, struct list_head *head)
174{
175#ifdef EXT4FS_DEBUG
176 struct list_head *cur, *before, *after;
177 ext4_io_end_t *io, *io0, *io1;
178
179 if (list_empty(head))
180 return;
181
182 ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
183 list_for_each_entry(io, head, list) {
184 cur = &io->list;
185 before = cur->prev;
186 io0 = container_of(before, ext4_io_end_t, list);
187 after = cur->next;
188 io1 = container_of(after, ext4_io_end_t, list);
189
190 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
191 io, inode->i_ino, io0, io1);
192 }
193#endif
194}
195
196/* Add the io_end to per-inode completed end_io list. */
197static void ext4_add_complete_io(ext4_io_end_t *io_end)
198{
199 struct ext4_inode_info *ei = EXT4_I(io_end->inode);
200 struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
201 struct workqueue_struct *wq;
202 unsigned long flags;
203
204 /* Only reserved conversions from writeback should enter here */
205 WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
206 WARN_ON(!io_end->handle && sbi->s_journal);
207 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
208 wq = sbi->rsv_conversion_wq;
209 if (list_empty(&ei->i_rsv_conversion_list))
210 queue_work(wq, &ei->i_rsv_conversion_work);
211 list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
212 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
213}
214
215static int ext4_do_flush_completed_IO(struct inode *inode,
216 struct list_head *head)
217{
218 ext4_io_end_t *io;
219 struct list_head unwritten;
220 unsigned long flags;
221 struct ext4_inode_info *ei = EXT4_I(inode);
222 int err, ret = 0;
223
224 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
225 dump_completed_IO(inode, head);
226 list_replace_init(head, &unwritten);
227 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
228
229 while (!list_empty(&unwritten)) {
230 io = list_entry(unwritten.next, ext4_io_end_t, list);
231 BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN));
232 list_del_init(&io->list);
233
234 err = ext4_end_io(io);
235 if (unlikely(!ret && err))
236 ret = err;
237 }
238 return ret;
239}
240
241/*
242 * work on completed IO, to convert unwritten extents to extents
243 */
244void ext4_end_io_rsv_work(struct work_struct *work)
245{
246 struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
247 i_rsv_conversion_work);
248 ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
249}
250
251ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
252{
253 ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
254 if (io) {
255 io->inode = inode;
256 INIT_LIST_HEAD(&io->list);
257 atomic_set(&io->count, 1);
258 }
259 return io;
260}
261
262void ext4_put_io_end_defer(ext4_io_end_t *io_end)
263{
264 if (atomic_dec_and_test(&io_end->count)) {
265 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || !io_end->size) {
266 ext4_release_io_end(io_end);
267 return;
268 }
269 ext4_add_complete_io(io_end);
270 }
271}
272
273int ext4_put_io_end(ext4_io_end_t *io_end)
274{
275 int err = 0;
276
277 if (atomic_dec_and_test(&io_end->count)) {
278 if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
279 err = ext4_convert_unwritten_extents(io_end->handle,
280 io_end->inode, io_end->offset,
281 io_end->size);
282 io_end->handle = NULL;
283 ext4_clear_io_unwritten_flag(io_end);
284 }
285 ext4_release_io_end(io_end);
286 }
287 return err;
288}
289
290ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
291{
292 atomic_inc(&io_end->count);
293 return io_end;
294}
295
296/* BIO completion function for page writeback */
297static void ext4_end_bio(struct bio *bio)
298{
299 ext4_io_end_t *io_end = bio->bi_private;
300 sector_t bi_sector = bio->bi_iter.bi_sector;
301
302 BUG_ON(!io_end);
303 bio->bi_end_io = NULL;
304
305 if (bio->bi_error) {
306 struct inode *inode = io_end->inode;
307
308 ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
309 "(offset %llu size %ld starting block %llu)",
310 bio->bi_error, inode->i_ino,
311 (unsigned long long) io_end->offset,
312 (long) io_end->size,
313 (unsigned long long)
314 bi_sector >> (inode->i_blkbits - 9));
315 mapping_set_error(inode->i_mapping, bio->bi_error);
316 }
317
318 if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
319 /*
320 * Link bio into list hanging from io_end. We have to do it
321 * atomically as bio completions can be racing against each
322 * other.
323 */
324 bio->bi_private = xchg(&io_end->bio, bio);
325 ext4_put_io_end_defer(io_end);
326 } else {
327 /*
328 * Drop io_end reference early. Inode can get freed once
329 * we finish the bio.
330 */
331 ext4_put_io_end_defer(io_end);
332 ext4_finish_bio(bio);
333 bio_put(bio);
334 }
335}
336
337void ext4_io_submit(struct ext4_io_submit *io)
338{
339 struct bio *bio = io->io_bio;
340
341 if (bio) {
342 int io_op_flags = io->io_wbc->sync_mode == WB_SYNC_ALL ?
343 REQ_SYNC : 0;
344 bio_set_op_attrs(io->io_bio, REQ_OP_WRITE, io_op_flags);
345 submit_bio(io->io_bio);
346 }
347 io->io_bio = NULL;
348}
349
350void ext4_io_submit_init(struct ext4_io_submit *io,
351 struct writeback_control *wbc)
352{
353 io->io_wbc = wbc;
354 io->io_bio = NULL;
355 io->io_end = NULL;
356}
357
358static int io_submit_init_bio(struct ext4_io_submit *io,
359 struct buffer_head *bh)
360{
361 struct bio *bio;
362
363 bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
364 if (!bio)
365 return -ENOMEM;
366 wbc_init_bio(io->io_wbc, bio);
367 bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
368 bio->bi_bdev = bh->b_bdev;
369 bio->bi_end_io = ext4_end_bio;
370 bio->bi_private = ext4_get_io_end(io->io_end);
371 io->io_bio = bio;
372 io->io_next_block = bh->b_blocknr;
373 return 0;
374}
375
376static int io_submit_add_bh(struct ext4_io_submit *io,
377 struct inode *inode,
378 struct page *page,
379 struct buffer_head *bh)
380{
381 int ret;
382
383 if (io->io_bio && bh->b_blocknr != io->io_next_block) {
384submit_and_retry:
385 ext4_io_submit(io);
386 }
387 if (io->io_bio == NULL) {
388 ret = io_submit_init_bio(io, bh);
389 if (ret)
390 return ret;
391 }
392 ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
393 if (ret != bh->b_size)
394 goto submit_and_retry;
395 wbc_account_io(io->io_wbc, page, bh->b_size);
396 io->io_next_block++;
397 return 0;
398}
399
400int ext4_bio_write_page(struct ext4_io_submit *io,
401 struct page *page,
402 int len,
403 struct writeback_control *wbc,
404 bool keep_towrite)
405{
406 struct page *data_page = NULL;
407 struct inode *inode = page->mapping->host;
408 unsigned block_start;
409 struct buffer_head *bh, *head;
410 int ret = 0;
411 int nr_submitted = 0;
412 int nr_to_submit = 0;
413
414 BUG_ON(!PageLocked(page));
415 BUG_ON(PageWriteback(page));
416
417 if (keep_towrite)
418 set_page_writeback_keepwrite(page);
419 else
420 set_page_writeback(page);
421 ClearPageError(page);
422
423 /*
424 * Comments copied from block_write_full_page:
425 *
426 * The page straddles i_size. It must be zeroed out on each and every
427 * writepage invocation because it may be mmapped. "A file is mapped
428 * in multiples of the page size. For a file that is not a multiple of
429 * the page size, the remaining memory is zeroed when mapped, and
430 * writes to that region are not written out to the file."
431 */
432 if (len < PAGE_SIZE)
433 zero_user_segment(page, len, PAGE_SIZE);
434 /*
435 * In the first loop we prepare and mark buffers to submit. We have to
436 * mark all buffers in the page before submitting so that
437 * end_page_writeback() cannot be called from ext4_bio_end_io() when IO
438 * on the first buffer finishes and we are still working on submitting
439 * the second buffer.
440 */
441 bh = head = page_buffers(page);
442 do {
443 block_start = bh_offset(bh);
444 if (block_start >= len) {
445 clear_buffer_dirty(bh);
446 set_buffer_uptodate(bh);
447 continue;
448 }
449 if (!buffer_dirty(bh) || buffer_delay(bh) ||
450 !buffer_mapped(bh) || buffer_unwritten(bh)) {
451 /* A hole? We can safely clear the dirty bit */
452 if (!buffer_mapped(bh))
453 clear_buffer_dirty(bh);
454 if (io->io_bio)
455 ext4_io_submit(io);
456 continue;
457 }
458 if (buffer_new(bh)) {
459 clear_buffer_new(bh);
460 clean_bdev_bh_alias(bh);
461 }
462 set_buffer_async_write(bh);
463 nr_to_submit++;
464 } while ((bh = bh->b_this_page) != head);
465
466 bh = head = page_buffers(page);
467
468 if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) &&
469 nr_to_submit) {
470 gfp_t gfp_flags = GFP_NOFS;
471
472 retry_encrypt:
473 data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0,
474 page->index, gfp_flags);
475 if (IS_ERR(data_page)) {
476 ret = PTR_ERR(data_page);
477 if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
478 if (io->io_bio) {
479 ext4_io_submit(io);
480 congestion_wait(BLK_RW_ASYNC, HZ/50);
481 }
482 gfp_flags |= __GFP_NOFAIL;
483 goto retry_encrypt;
484 }
485 data_page = NULL;
486 goto out;
487 }
488 }
489
490 /* Now submit buffers to write */
491 do {
492 if (!buffer_async_write(bh))
493 continue;
494 ret = io_submit_add_bh(io, inode,
495 data_page ? data_page : page, bh);
496 if (ret) {
497 /*
498 * We only get here on ENOMEM. Not much else
499 * we can do but mark the page as dirty, and
500 * better luck next time.
501 */
502 break;
503 }
504 nr_submitted++;
505 clear_buffer_dirty(bh);
506 } while ((bh = bh->b_this_page) != head);
507
508 /* Error stopped previous loop? Clean up buffers... */
509 if (ret) {
510 out:
511 if (data_page)
512 fscrypt_restore_control_page(data_page);
513 printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
514 redirty_page_for_writepage(wbc, page);
515 do {
516 clear_buffer_async_write(bh);
517 bh = bh->b_this_page;
518 } while (bh != head);
519 }
520 unlock_page(page);
521 /* Nothing submitted - we have to end page writeback */
522 if (!nr_submitted)
523 end_page_writeback(page);
524 return ret;
525}
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
33static struct kmem_cache *io_end_cachep;
34static struct kmem_cache *io_end_vec_cachep;
35
36int __init ext4_init_pageio(void)
37{
38 io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
39 if (io_end_cachep == NULL)
40 return -ENOMEM;
41
42 io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0);
43 if (io_end_vec_cachep == NULL) {
44 kmem_cache_destroy(io_end_cachep);
45 return -ENOMEM;
46 }
47 return 0;
48}
49
50void ext4_exit_pageio(void)
51{
52 kmem_cache_destroy(io_end_cachep);
53 kmem_cache_destroy(io_end_vec_cachep);
54}
55
56struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end)
57{
58 struct ext4_io_end_vec *io_end_vec;
59
60 io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS);
61 if (!io_end_vec)
62 return ERR_PTR(-ENOMEM);
63 INIT_LIST_HEAD(&io_end_vec->list);
64 list_add_tail(&io_end_vec->list, &io_end->list_vec);
65 return io_end_vec;
66}
67
68static void ext4_free_io_end_vec(ext4_io_end_t *io_end)
69{
70 struct ext4_io_end_vec *io_end_vec, *tmp;
71
72 if (list_empty(&io_end->list_vec))
73 return;
74 list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) {
75 list_del(&io_end_vec->list);
76 kmem_cache_free(io_end_vec_cachep, io_end_vec);
77 }
78}
79
80struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end)
81{
82 BUG_ON(list_empty(&io_end->list_vec));
83 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 */
93static void buffer_io_error(struct buffer_head *bh)
94{
95 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}
99
100static void ext4_finish_bio(struct bio *bio)
101{
102 struct bio_vec *bvec;
103 struct bvec_iter_all iter_all;
104
105 bio_for_each_segment_all(bvec, bio, iter_all) {
106 struct page *page = bvec->bv_page;
107 struct page *bounce_page = NULL;
108 struct buffer_head *bh, *head;
109 unsigned bio_start = bvec->bv_offset;
110 unsigned bio_end = bio_start + bvec->bv_len;
111 unsigned under_io = 0;
112 unsigned long flags;
113
114 if (fscrypt_is_bounce_page(page)) {
115 bounce_page = page;
116 page = fscrypt_pagecache_page(bounce_page);
117 }
118
119 if (bio->bi_status) {
120 SetPageError(page);
121 mapping_set_error(page->mapping, -EIO);
122 }
123 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 spin_lock_irqsave(&head->b_uptodate_lock, flags);
129 do {
130 if (bh_offset(bh) < bio_start ||
131 bh_offset(bh) + bh->b_size > bio_end) {
132 if (buffer_async_write(bh))
133 under_io++;
134 continue;
135 }
136 clear_buffer_async_write(bh);
137 if (bio->bi_status)
138 buffer_io_error(bh);
139 } while ((bh = bh->b_this_page) != head);
140 spin_unlock_irqrestore(&head->b_uptodate_lock, flags);
141 if (!under_io) {
142 fscrypt_free_bounce_page(bounce_page);
143 end_page_writeback(page);
144 }
145 }
146}
147
148static void ext4_release_io_end(ext4_io_end_t *io_end)
149{
150 struct bio *bio, *next_bio;
151
152 BUG_ON(!list_empty(&io_end->list));
153 BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
154 WARN_ON(io_end->handle);
155
156 for (bio = io_end->bio; bio; bio = next_bio) {
157 next_bio = bio->bi_private;
158 ext4_finish_bio(bio);
159 bio_put(bio);
160 }
161 ext4_free_io_end_vec(io_end);
162 kmem_cache_free(io_end_cachep, io_end);
163}
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 */
173static int ext4_end_io_end(ext4_io_end_t *io_end)
174{
175 struct inode *inode = io_end->inode;
176 handle_t *handle = io_end->handle;
177 int ret = 0;
178
179 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 io_end->handle = NULL; /* Following call will use up the handle */
184 ret = ext4_convert_unwritten_io_end_vec(handle, io_end);
185 if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) {
186 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 ext4_clear_io_unwritten_flag(io_end);
192 ext4_release_io_end(io_end);
193 return ret;
194}
195
196static 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}
218
219/* Add the io_end to per-inode completed end_io list. */
220static void ext4_add_complete_io(ext4_io_end_t *io_end)
221{
222 struct ext4_inode_info *ei = EXT4_I(io_end->inode);
223 struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
224 struct workqueue_struct *wq;
225 unsigned long flags;
226
227 /* Only reserved conversions from writeback should enter here */
228 WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
229 WARN_ON(!io_end->handle && sbi->s_journal);
230 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
231 wq = sbi->rsv_conversion_wq;
232 if (list_empty(&ei->i_rsv_conversion_list))
233 queue_work(wq, &ei->i_rsv_conversion_work);
234 list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
235 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
236}
237
238static int ext4_do_flush_completed_IO(struct inode *inode,
239 struct list_head *head)
240{
241 ext4_io_end_t *io_end;
242 struct list_head unwritten;
243 unsigned long flags;
244 struct ext4_inode_info *ei = EXT4_I(inode);
245 int err, ret = 0;
246
247 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
248 dump_completed_IO(inode, head);
249 list_replace_init(head, &unwritten);
250 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
251
252 while (!list_empty(&unwritten)) {
253 io_end = list_entry(unwritten.next, ext4_io_end_t, list);
254 BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
255 list_del_init(&io_end->list);
256
257 err = ext4_end_io_end(io_end);
258 if (unlikely(!ret && err))
259 ret = err;
260 }
261 return ret;
262}
263
264/*
265 * work on completed IO, to convert unwritten extents to extents
266 */
267void ext4_end_io_rsv_work(struct work_struct *work)
268{
269 struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
270 i_rsv_conversion_work);
271 ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
272}
273
274ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
275{
276 ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags);
277
278 if (io_end) {
279 io_end->inode = inode;
280 INIT_LIST_HEAD(&io_end->list);
281 INIT_LIST_HEAD(&io_end->list_vec);
282 atomic_set(&io_end->count, 1);
283 }
284 return io_end;
285}
286
287void ext4_put_io_end_defer(ext4_io_end_t *io_end)
288{
289 if (atomic_dec_and_test(&io_end->count)) {
290 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) ||
291 list_empty(&io_end->list_vec)) {
292 ext4_release_io_end(io_end);
293 return;
294 }
295 ext4_add_complete_io(io_end);
296 }
297}
298
299int ext4_put_io_end(ext4_io_end_t *io_end)
300{
301 int err = 0;
302
303 if (atomic_dec_and_test(&io_end->count)) {
304 if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
305 err = ext4_convert_unwritten_io_end_vec(io_end->handle,
306 io_end);
307 io_end->handle = NULL;
308 ext4_clear_io_unwritten_flag(io_end);
309 }
310 ext4_release_io_end(io_end);
311 }
312 return err;
313}
314
315ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
316{
317 atomic_inc(&io_end->count);
318 return io_end;
319}
320
321/* BIO completion function for page writeback */
322static void ext4_end_bio(struct bio *bio)
323{
324 ext4_io_end_t *io_end = bio->bi_private;
325 sector_t bi_sector = bio->bi_iter.bi_sector;
326 char b[BDEVNAME_SIZE];
327
328 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 ext4_finish_bio(bio);
334 bio_put(bio);
335 return;
336 }
337 bio->bi_end_io = NULL;
338
339 if (bio->bi_status) {
340 struct inode *inode = io_end->inode;
341
342 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 mapping_set_error(inode->i_mapping,
348 blk_status_to_errno(bio->bi_status));
349 }
350
351 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 bio->bi_private = xchg(&io_end->bio, bio);
358 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 ext4_put_io_end_defer(io_end);
365 ext4_finish_bio(bio);
366 bio_put(bio);
367 }
368}
369
370void ext4_io_submit(struct ext4_io_submit *io)
371{
372 struct bio *bio = io->io_bio;
373
374 if (bio) {
375 int io_op_flags = io->io_wbc->sync_mode == WB_SYNC_ALL ?
376 REQ_SYNC : 0;
377 io->io_bio->bi_write_hint = io->io_end->inode->i_write_hint;
378 bio_set_op_attrs(io->io_bio, REQ_OP_WRITE, io_op_flags);
379 submit_bio(io->io_bio);
380 }
381 io->io_bio = NULL;
382}
383
384void ext4_io_submit_init(struct ext4_io_submit *io,
385 struct writeback_control *wbc)
386{
387 io->io_wbc = wbc;
388 io->io_bio = NULL;
389 io->io_end = NULL;
390}
391
392static void io_submit_init_bio(struct ext4_io_submit *io,
393 struct buffer_head *bh)
394{
395 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 bio = bio_alloc(GFP_NOIO, BIO_MAX_VECS);
402 fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
403 bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
404 bio_set_dev(bio, bh->b_bdev);
405 bio->bi_end_io = ext4_end_bio;
406 bio->bi_private = ext4_get_io_end(io->io_end);
407 io->io_bio = bio;
408 io->io_next_block = bh->b_blocknr;
409 wbc_init_bio(io->io_wbc, bio);
410}
411
412static 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 int ret;
418
419 if (io->io_bio && (bh->b_blocknr != io->io_next_block ||
420 !fscrypt_mergeable_bio_bh(io->io_bio, bh))) {
421submit_and_retry:
422 ext4_io_submit(io);
423 }
424 if (io->io_bio == NULL) {
425 io_submit_init_bio(io, bh);
426 io->io_bio->bi_write_hint = inode->i_write_hint;
427 }
428 ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
429 if (ret != bh->b_size)
430 goto submit_and_retry;
431 wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size);
432 io->io_next_block++;
433}
434
435int ext4_bio_write_page(struct ext4_io_submit *io,
436 struct page *page,
437 int len,
438 bool keep_towrite)
439{
440 struct page *bounce_page = NULL;
441 struct inode *inode = page->mapping->host;
442 unsigned block_start;
443 struct buffer_head *bh, *head;
444 int ret = 0;
445 int nr_submitted = 0;
446 int nr_to_submit = 0;
447 struct writeback_control *wbc = io->io_wbc;
448
449 BUG_ON(!PageLocked(page));
450 BUG_ON(PageWriteback(page));
451
452 if (keep_towrite)
453 set_page_writeback_keepwrite(page);
454 else
455 set_page_writeback(page);
456 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 if (len < PAGE_SIZE)
468 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 bh = head = page_buffers(page);
477 do {
478 block_start = bh_offset(bh);
479 if (block_start >= len) {
480 clear_buffer_dirty(bh);
481 set_buffer_uptodate(bh);
482 continue;
483 }
484 if (!buffer_dirty(bh) || buffer_delay(bh) ||
485 !buffer_mapped(bh) || buffer_unwritten(bh)) {
486 /* A hole? We can safely clear the dirty bit */
487 if (!buffer_mapped(bh))
488 clear_buffer_dirty(bh);
489 if (io->io_bio)
490 ext4_io_submit(io);
491 continue;
492 }
493 if (buffer_new(bh))
494 clear_buffer_new(bh);
495 set_buffer_async_write(bh);
496 nr_to_submit++;
497 } while ((bh = bh->b_this_page) != head);
498
499 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 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 do {
547 if (!buffer_async_write(bh))
548 continue;
549 io_submit_add_bh(io, inode,
550 bounce_page ? bounce_page : page, bh);
551 nr_submitted++;
552 clear_buffer_dirty(bh);
553 } while ((bh = bh->b_this_page) != head);
554
555unlock:
556 unlock_page(page);
557 /* Nothing submitted - we have to end page writeback */
558 if (!nr_submitted)
559 end_page_writeback(page);
560 return ret;
561}