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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/module.h>
10#include <linux/fs.h>
11#include <linux/time.h>
12#include <linux/jbd2.h>
13#include <linux/highuid.h>
14#include <linux/pagemap.h>
15#include <linux/quotaops.h>
16#include <linux/string.h>
17#include <linux/buffer_head.h>
18#include <linux/writeback.h>
19#include <linux/pagevec.h>
20#include <linux/mpage.h>
21#include <linux/namei.h>
22#include <linux/uio.h>
23#include <linux/bio.h>
24#include <linux/workqueue.h>
25#include <linux/kernel.h>
26#include <linux/slab.h>
27
28#include "ext4_jbd2.h"
29#include "xattr.h"
30#include "acl.h"
31#include "ext4_extents.h"
32
33static struct kmem_cache *io_page_cachep, *io_end_cachep;
34
35int __init ext4_init_pageio(void)
36{
37 io_page_cachep = KMEM_CACHE(ext4_io_page, SLAB_RECLAIM_ACCOUNT);
38 if (io_page_cachep == NULL)
39 return -ENOMEM;
40 io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
41 if (io_end_cachep == NULL) {
42 kmem_cache_destroy(io_page_cachep);
43 return -ENOMEM;
44 }
45 return 0;
46}
47
48void ext4_exit_pageio(void)
49{
50 kmem_cache_destroy(io_end_cachep);
51 kmem_cache_destroy(io_page_cachep);
52}
53
54void ext4_ioend_wait(struct inode *inode)
55{
56 wait_queue_head_t *wq = ext4_ioend_wq(inode);
57
58 wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0));
59}
60
61static void put_io_page(struct ext4_io_page *io_page)
62{
63 if (atomic_dec_and_test(&io_page->p_count)) {
64 end_page_writeback(io_page->p_page);
65 put_page(io_page->p_page);
66 kmem_cache_free(io_page_cachep, io_page);
67 }
68}
69
70void ext4_free_io_end(ext4_io_end_t *io)
71{
72 int i;
73 wait_queue_head_t *wq;
74
75 BUG_ON(!io);
76 if (io->page)
77 put_page(io->page);
78 for (i = 0; i < io->num_io_pages; i++)
79 put_io_page(io->pages[i]);
80 io->num_io_pages = 0;
81 wq = ext4_ioend_wq(io->inode);
82 if (atomic_dec_and_test(&EXT4_I(io->inode)->i_ioend_count) &&
83 waitqueue_active(wq))
84 wake_up_all(wq);
85 kmem_cache_free(io_end_cachep, io);
86}
87
88/*
89 * check a range of space and convert unwritten extents to written.
90 */
91int ext4_end_io_nolock(ext4_io_end_t *io)
92{
93 struct inode *inode = io->inode;
94 loff_t offset = io->offset;
95 ssize_t size = io->size;
96 wait_queue_head_t *wq;
97 int ret = 0;
98
99 ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
100 "list->prev 0x%p\n",
101 io, inode->i_ino, io->list.next, io->list.prev);
102
103 if (list_empty(&io->list))
104 return ret;
105
106 if (!(io->flag & EXT4_IO_END_UNWRITTEN))
107 return ret;
108
109 ret = ext4_convert_unwritten_extents(inode, offset, size);
110 if (ret < 0) {
111 printk(KERN_EMERG "%s: failed to convert unwritten "
112 "extents to written extents, error is %d "
113 "io is still on inode %lu aio dio list\n",
114 __func__, ret, inode->i_ino);
115 return ret;
116 }
117
118 if (io->iocb)
119 aio_complete(io->iocb, io->result, 0);
120 /* clear the DIO AIO unwritten flag */
121 if (io->flag & EXT4_IO_END_UNWRITTEN) {
122 io->flag &= ~EXT4_IO_END_UNWRITTEN;
123 /* Wake up anyone waiting on unwritten extent conversion */
124 wq = ext4_ioend_wq(io->inode);
125 if (atomic_dec_and_test(&EXT4_I(inode)->i_aiodio_unwritten) &&
126 waitqueue_active(wq)) {
127 wake_up_all(wq);
128 }
129 }
130
131 return ret;
132}
133
134/*
135 * work on completed aio dio IO, to convert unwritten extents to extents
136 */
137static void ext4_end_io_work(struct work_struct *work)
138{
139 ext4_io_end_t *io = container_of(work, ext4_io_end_t, work);
140 struct inode *inode = io->inode;
141 struct ext4_inode_info *ei = EXT4_I(inode);
142 unsigned long flags;
143 int ret;
144
145 if (!mutex_trylock(&inode->i_mutex)) {
146 /*
147 * Requeue the work instead of waiting so that the work
148 * items queued after this can be processed.
149 */
150 queue_work(EXT4_SB(inode->i_sb)->dio_unwritten_wq, &io->work);
151 /*
152 * To prevent the ext4-dio-unwritten thread from keeping
153 * requeueing end_io requests and occupying cpu for too long,
154 * yield the cpu if it sees an end_io request that has already
155 * been requeued.
156 */
157 if (io->flag & EXT4_IO_END_QUEUED)
158 yield();
159 io->flag |= EXT4_IO_END_QUEUED;
160 return;
161 }
162 ret = ext4_end_io_nolock(io);
163 if (ret < 0) {
164 mutex_unlock(&inode->i_mutex);
165 return;
166 }
167
168 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
169 if (!list_empty(&io->list))
170 list_del_init(&io->list);
171 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
172 mutex_unlock(&inode->i_mutex);
173 ext4_free_io_end(io);
174}
175
176ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
177{
178 ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
179 if (io) {
180 atomic_inc(&EXT4_I(inode)->i_ioend_count);
181 io->inode = inode;
182 INIT_WORK(&io->work, ext4_end_io_work);
183 INIT_LIST_HEAD(&io->list);
184 }
185 return io;
186}
187
188/*
189 * Print an buffer I/O error compatible with the fs/buffer.c. This
190 * provides compatibility with dmesg scrapers that look for a specific
191 * buffer I/O error message. We really need a unified error reporting
192 * structure to userspace ala Digital Unix's uerf system, but it's
193 * probably not going to happen in my lifetime, due to LKML politics...
194 */
195static void buffer_io_error(struct buffer_head *bh)
196{
197 char b[BDEVNAME_SIZE];
198 printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n",
199 bdevname(bh->b_bdev, b),
200 (unsigned long long)bh->b_blocknr);
201}
202
203static void ext4_end_bio(struct bio *bio, int error)
204{
205 ext4_io_end_t *io_end = bio->bi_private;
206 struct workqueue_struct *wq;
207 struct inode *inode;
208 unsigned long flags;
209 int i;
210 sector_t bi_sector = bio->bi_sector;
211
212 BUG_ON(!io_end);
213 bio->bi_private = NULL;
214 bio->bi_end_io = NULL;
215 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
216 error = 0;
217 bio_put(bio);
218
219 for (i = 0; i < io_end->num_io_pages; i++) {
220 struct page *page = io_end->pages[i]->p_page;
221 struct buffer_head *bh, *head;
222 loff_t offset;
223 loff_t io_end_offset;
224
225 if (error) {
226 SetPageError(page);
227 set_bit(AS_EIO, &page->mapping->flags);
228 head = page_buffers(page);
229 BUG_ON(!head);
230
231 io_end_offset = io_end->offset + io_end->size;
232
233 offset = (sector_t) page->index << PAGE_CACHE_SHIFT;
234 bh = head;
235 do {
236 if ((offset >= io_end->offset) &&
237 (offset+bh->b_size <= io_end_offset))
238 buffer_io_error(bh);
239
240 offset += bh->b_size;
241 bh = bh->b_this_page;
242 } while (bh != head);
243 }
244
245 put_io_page(io_end->pages[i]);
246 }
247 io_end->num_io_pages = 0;
248 inode = io_end->inode;
249
250 if (error) {
251 io_end->flag |= EXT4_IO_END_ERROR;
252 ext4_warning(inode->i_sb, "I/O error writing to inode %lu "
253 "(offset %llu size %ld starting block %llu)",
254 inode->i_ino,
255 (unsigned long long) io_end->offset,
256 (long) io_end->size,
257 (unsigned long long)
258 bi_sector >> (inode->i_blkbits - 9));
259 }
260
261 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
262 ext4_free_io_end(io_end);
263 return;
264 }
265
266 /* Add the io_end to per-inode completed io list*/
267 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
268 list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
269 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
270
271 wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
272 /* queue the work to convert unwritten extents to written */
273 queue_work(wq, &io_end->work);
274}
275
276void ext4_io_submit(struct ext4_io_submit *io)
277{
278 struct bio *bio = io->io_bio;
279
280 if (bio) {
281 bio_get(io->io_bio);
282 submit_bio(io->io_op, io->io_bio);
283 BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP));
284 bio_put(io->io_bio);
285 }
286 io->io_bio = NULL;
287 io->io_op = 0;
288 io->io_end = NULL;
289}
290
291static int io_submit_init(struct ext4_io_submit *io,
292 struct inode *inode,
293 struct writeback_control *wbc,
294 struct buffer_head *bh)
295{
296 ext4_io_end_t *io_end;
297 struct page *page = bh->b_page;
298 int nvecs = bio_get_nr_vecs(bh->b_bdev);
299 struct bio *bio;
300
301 io_end = ext4_init_io_end(inode, GFP_NOFS);
302 if (!io_end)
303 return -ENOMEM;
304 bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES));
305 bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
306 bio->bi_bdev = bh->b_bdev;
307 bio->bi_private = io->io_end = io_end;
308 bio->bi_end_io = ext4_end_bio;
309
310 io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh);
311
312 io->io_bio = bio;
313 io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
314 io->io_next_block = bh->b_blocknr;
315 return 0;
316}
317
318static int io_submit_add_bh(struct ext4_io_submit *io,
319 struct ext4_io_page *io_page,
320 struct inode *inode,
321 struct writeback_control *wbc,
322 struct buffer_head *bh)
323{
324 ext4_io_end_t *io_end;
325 int ret;
326
327 if (buffer_new(bh)) {
328 clear_buffer_new(bh);
329 unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
330 }
331
332 if (!buffer_mapped(bh) || buffer_delay(bh)) {
333 if (!buffer_mapped(bh))
334 clear_buffer_dirty(bh);
335 if (io->io_bio)
336 ext4_io_submit(io);
337 return 0;
338 }
339
340 if (io->io_bio && bh->b_blocknr != io->io_next_block) {
341submit_and_retry:
342 ext4_io_submit(io);
343 }
344 if (io->io_bio == NULL) {
345 ret = io_submit_init(io, inode, wbc, bh);
346 if (ret)
347 return ret;
348 }
349 io_end = io->io_end;
350 if ((io_end->num_io_pages >= MAX_IO_PAGES) &&
351 (io_end->pages[io_end->num_io_pages-1] != io_page))
352 goto submit_and_retry;
353 if (buffer_uninit(bh) && !(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
354 io_end->flag |= EXT4_IO_END_UNWRITTEN;
355 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
356 }
357 io->io_end->size += bh->b_size;
358 io->io_next_block++;
359 ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));
360 if (ret != bh->b_size)
361 goto submit_and_retry;
362 if ((io_end->num_io_pages == 0) ||
363 (io_end->pages[io_end->num_io_pages-1] != io_page)) {
364 io_end->pages[io_end->num_io_pages++] = io_page;
365 atomic_inc(&io_page->p_count);
366 }
367 return 0;
368}
369
370int ext4_bio_write_page(struct ext4_io_submit *io,
371 struct page *page,
372 int len,
373 struct writeback_control *wbc)
374{
375 struct inode *inode = page->mapping->host;
376 unsigned block_start, block_end, blocksize;
377 struct ext4_io_page *io_page;
378 struct buffer_head *bh, *head;
379 int ret = 0;
380
381 blocksize = 1 << inode->i_blkbits;
382
383 BUG_ON(!PageLocked(page));
384 BUG_ON(PageWriteback(page));
385
386 io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS);
387 if (!io_page) {
388 set_page_dirty(page);
389 unlock_page(page);
390 return -ENOMEM;
391 }
392 io_page->p_page = page;
393 atomic_set(&io_page->p_count, 1);
394 get_page(page);
395 set_page_writeback(page);
396 ClearPageError(page);
397
398 for (bh = head = page_buffers(page), block_start = 0;
399 bh != head || !block_start;
400 block_start = block_end, bh = bh->b_this_page) {
401
402 block_end = block_start + blocksize;
403 if (block_start >= len) {
404 clear_buffer_dirty(bh);
405 set_buffer_uptodate(bh);
406 continue;
407 }
408 clear_buffer_dirty(bh);
409 ret = io_submit_add_bh(io, io_page, inode, wbc, bh);
410 if (ret) {
411 /*
412 * We only get here on ENOMEM. Not much else
413 * we can do but mark the page as dirty, and
414 * better luck next time.
415 */
416 set_page_dirty(page);
417 break;
418 }
419 }
420 unlock_page(page);
421 /*
422 * If the page was truncated before we could do the writeback,
423 * or we had a memory allocation error while trying to write
424 * the first buffer head, we won't have submitted any pages for
425 * I/O. In that case we need to make sure we've cleared the
426 * PageWriteback bit from the page to prevent the system from
427 * wedging later on.
428 */
429 put_io_page(io_page);
430 return ret;
431}
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
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 folio_iter fi;
103
104 bio_for_each_folio_all(fi, bio) {
105 struct folio *folio = fi.folio;
106 struct folio *io_folio = NULL;
107 struct buffer_head *bh, *head;
108 size_t bio_start = fi.offset;
109 size_t bio_end = bio_start + fi.length;
110 unsigned under_io = 0;
111 unsigned long flags;
112
113 if (fscrypt_is_bounce_folio(folio)) {
114 io_folio = folio;
115 folio = fscrypt_pagecache_folio(folio);
116 }
117
118 if (bio->bi_status) {
119 int err = blk_status_to_errno(bio->bi_status);
120 mapping_set_error(folio->mapping, err);
121 }
122 bh = head = folio_buffers(folio);
123 /*
124 * We check all buffers in the folio under b_uptodate_lock
125 * to avoid races with other end io clearing async_write flags
126 */
127 spin_lock_irqsave(&head->b_uptodate_lock, flags);
128 do {
129 if (bh_offset(bh) < bio_start ||
130 bh_offset(bh) + bh->b_size > bio_end) {
131 if (buffer_async_write(bh))
132 under_io++;
133 continue;
134 }
135 clear_buffer_async_write(bh);
136 if (bio->bi_status) {
137 set_buffer_write_io_error(bh);
138 buffer_io_error(bh);
139 }
140 } while ((bh = bh->b_this_page) != head);
141 spin_unlock_irqrestore(&head->b_uptodate_lock, flags);
142 if (!under_io) {
143 fscrypt_free_bounce_page(&io_folio->page);
144 folio_end_writeback(folio);
145 }
146 }
147}
148
149static void ext4_release_io_end(ext4_io_end_t *io_end)
150{
151 struct bio *bio, *next_bio;
152
153 BUG_ON(!list_empty(&io_end->list));
154 BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
155 WARN_ON(io_end->handle);
156
157 for (bio = io_end->bio; bio; bio = next_bio) {
158 next_bio = bio->bi_private;
159 ext4_finish_bio(bio);
160 bio_put(bio);
161 }
162 ext4_free_io_end_vec(io_end);
163 kmem_cache_free(io_end_cachep, io_end);
164}
165
166/*
167 * Check a range of space and convert unwritten extents to written. Note that
168 * we are protected from truncate touching same part of extent tree by the
169 * fact that truncate code waits for all DIO to finish (thus exclusion from
170 * direct IO is achieved) and also waits for PageWriteback bits. Thus we
171 * cannot get to ext4_ext_truncate() before all IOs overlapping that range are
172 * completed (happens from ext4_free_ioend()).
173 */
174static int ext4_end_io_end(ext4_io_end_t *io_end)
175{
176 struct inode *inode = io_end->inode;
177 handle_t *handle = io_end->handle;
178 int ret = 0;
179
180 ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p,"
181 "list->prev 0x%p\n",
182 io_end, inode->i_ino, io_end->list.next, io_end->list.prev);
183
184 io_end->handle = NULL; /* Following call will use up the handle */
185 ret = ext4_convert_unwritten_io_end_vec(handle, io_end);
186 if (ret < 0 && !ext4_forced_shutdown(inode->i_sb)) {
187 ext4_msg(inode->i_sb, KERN_EMERG,
188 "failed to convert unwritten extents to written "
189 "extents -- potential data loss! "
190 "(inode %lu, error %d)", inode->i_ino, ret);
191 }
192 ext4_clear_io_unwritten_flag(io_end);
193 ext4_release_io_end(io_end);
194 return ret;
195}
196
197static void dump_completed_IO(struct inode *inode, struct list_head *head)
198{
199#ifdef EXT4FS_DEBUG
200 struct list_head *cur, *before, *after;
201 ext4_io_end_t *io_end, *io_end0, *io_end1;
202
203 if (list_empty(head))
204 return;
205
206 ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
207 list_for_each_entry(io_end, head, list) {
208 cur = &io_end->list;
209 before = cur->prev;
210 io_end0 = container_of(before, ext4_io_end_t, list);
211 after = cur->next;
212 io_end1 = container_of(after, ext4_io_end_t, list);
213
214 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
215 io_end, inode->i_ino, io_end0, io_end1);
216 }
217#endif
218}
219
220/* Add the io_end to per-inode completed end_io list. */
221static void ext4_add_complete_io(ext4_io_end_t *io_end)
222{
223 struct ext4_inode_info *ei = EXT4_I(io_end->inode);
224 struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
225 struct workqueue_struct *wq;
226 unsigned long flags;
227
228 /* Only reserved conversions from writeback should enter here */
229 WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
230 WARN_ON(!io_end->handle && sbi->s_journal);
231 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
232 wq = sbi->rsv_conversion_wq;
233 if (list_empty(&ei->i_rsv_conversion_list))
234 queue_work(wq, &ei->i_rsv_conversion_work);
235 list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
236 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
237}
238
239static int ext4_do_flush_completed_IO(struct inode *inode,
240 struct list_head *head)
241{
242 ext4_io_end_t *io_end;
243 struct list_head unwritten;
244 unsigned long flags;
245 struct ext4_inode_info *ei = EXT4_I(inode);
246 int err, ret = 0;
247
248 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
249 dump_completed_IO(inode, head);
250 list_replace_init(head, &unwritten);
251 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
252
253 while (!list_empty(&unwritten)) {
254 io_end = list_entry(unwritten.next, ext4_io_end_t, list);
255 BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
256 list_del_init(&io_end->list);
257
258 err = ext4_end_io_end(io_end);
259 if (unlikely(!ret && err))
260 ret = err;
261 }
262 return ret;
263}
264
265/*
266 * work on completed IO, to convert unwritten extents to extents
267 */
268void ext4_end_io_rsv_work(struct work_struct *work)
269{
270 struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
271 i_rsv_conversion_work);
272 ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
273}
274
275ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
276{
277 ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags);
278
279 if (io_end) {
280 io_end->inode = inode;
281 INIT_LIST_HEAD(&io_end->list);
282 INIT_LIST_HEAD(&io_end->list_vec);
283 refcount_set(&io_end->count, 1);
284 }
285 return io_end;
286}
287
288void ext4_put_io_end_defer(ext4_io_end_t *io_end)
289{
290 if (refcount_dec_and_test(&io_end->count)) {
291 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) ||
292 list_empty(&io_end->list_vec)) {
293 ext4_release_io_end(io_end);
294 return;
295 }
296 ext4_add_complete_io(io_end);
297 }
298}
299
300int ext4_put_io_end(ext4_io_end_t *io_end)
301{
302 int err = 0;
303
304 if (refcount_dec_and_test(&io_end->count)) {
305 if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
306 err = ext4_convert_unwritten_io_end_vec(io_end->handle,
307 io_end);
308 io_end->handle = NULL;
309 ext4_clear_io_unwritten_flag(io_end);
310 }
311 ext4_release_io_end(io_end);
312 }
313 return err;
314}
315
316ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
317{
318 refcount_inc(&io_end->count);
319 return io_end;
320}
321
322/* BIO completion function for page writeback */
323static void ext4_end_bio(struct bio *bio)
324{
325 ext4_io_end_t *io_end = bio->bi_private;
326 sector_t bi_sector = bio->bi_iter.bi_sector;
327
328 if (WARN_ONCE(!io_end, "io_end is NULL: %pg: sector %Lu len %u err %d\n",
329 bio->bi_bdev,
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 if (io->io_wbc->sync_mode == WB_SYNC_ALL)
376 io->io_bio->bi_opf |= REQ_SYNC;
377 submit_bio(io->io_bio);
378 }
379 io->io_bio = NULL;
380}
381
382void ext4_io_submit_init(struct ext4_io_submit *io,
383 struct writeback_control *wbc)
384{
385 io->io_wbc = wbc;
386 io->io_bio = NULL;
387 io->io_end = NULL;
388}
389
390static void io_submit_init_bio(struct ext4_io_submit *io,
391 struct buffer_head *bh)
392{
393 struct bio *bio;
394
395 /*
396 * bio_alloc will _always_ be able to allocate a bio if
397 * __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset().
398 */
399 bio = bio_alloc(bh->b_bdev, BIO_MAX_VECS, REQ_OP_WRITE, GFP_NOIO);
400 fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
401 bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
402 bio->bi_end_io = ext4_end_bio;
403 bio->bi_private = ext4_get_io_end(io->io_end);
404 io->io_bio = bio;
405 io->io_next_block = bh->b_blocknr;
406 wbc_init_bio(io->io_wbc, bio);
407}
408
409static void io_submit_add_bh(struct ext4_io_submit *io,
410 struct inode *inode,
411 struct folio *folio,
412 struct folio *io_folio,
413 struct buffer_head *bh)
414{
415 if (io->io_bio && (bh->b_blocknr != io->io_next_block ||
416 !fscrypt_mergeable_bio_bh(io->io_bio, bh))) {
417submit_and_retry:
418 ext4_io_submit(io);
419 }
420 if (io->io_bio == NULL) {
421 io_submit_init_bio(io, bh);
422 io->io_bio->bi_write_hint = inode->i_write_hint;
423 }
424 if (!bio_add_folio(io->io_bio, io_folio, bh->b_size, bh_offset(bh)))
425 goto submit_and_retry;
426 wbc_account_cgroup_owner(io->io_wbc, folio, bh->b_size);
427 io->io_next_block++;
428}
429
430int ext4_bio_write_folio(struct ext4_io_submit *io, struct folio *folio,
431 size_t len)
432{
433 struct folio *io_folio = folio;
434 struct inode *inode = folio->mapping->host;
435 unsigned block_start;
436 struct buffer_head *bh, *head;
437 int ret = 0;
438 int nr_to_submit = 0;
439 struct writeback_control *wbc = io->io_wbc;
440 bool keep_towrite = false;
441
442 BUG_ON(!folio_test_locked(folio));
443 BUG_ON(folio_test_writeback(folio));
444
445 /*
446 * Comments copied from block_write_full_folio:
447 *
448 * The folio straddles i_size. It must be zeroed out on each and every
449 * writepage invocation because it may be mmapped. "A file is mapped
450 * in multiples of the page size. For a file that is not a multiple of
451 * the page size, the remaining memory is zeroed when mapped, and
452 * writes to that region are not written out to the file."
453 */
454 if (len < folio_size(folio))
455 folio_zero_segment(folio, len, folio_size(folio));
456 /*
457 * In the first loop we prepare and mark buffers to submit. We have to
458 * mark all buffers in the folio before submitting so that
459 * folio_end_writeback() cannot be called from ext4_end_bio() when IO
460 * on the first buffer finishes and we are still working on submitting
461 * the second buffer.
462 */
463 bh = head = folio_buffers(folio);
464 do {
465 block_start = bh_offset(bh);
466 if (block_start >= len) {
467 clear_buffer_dirty(bh);
468 set_buffer_uptodate(bh);
469 continue;
470 }
471 if (!buffer_dirty(bh) || buffer_delay(bh) ||
472 !buffer_mapped(bh) || buffer_unwritten(bh)) {
473 /* A hole? We can safely clear the dirty bit */
474 if (!buffer_mapped(bh))
475 clear_buffer_dirty(bh);
476 /*
477 * Keeping dirty some buffer we cannot write? Make sure
478 * to redirty the folio and keep TOWRITE tag so that
479 * racing WB_SYNC_ALL writeback does not skip the folio.
480 * This happens e.g. when doing writeout for
481 * transaction commit or when journalled data is not
482 * yet committed.
483 */
484 if (buffer_dirty(bh) ||
485 (buffer_jbd(bh) && buffer_jbddirty(bh))) {
486 if (!folio_test_dirty(folio))
487 folio_redirty_for_writepage(wbc, folio);
488 keep_towrite = true;
489 }
490 continue;
491 }
492 if (buffer_new(bh))
493 clear_buffer_new(bh);
494 set_buffer_async_write(bh);
495 clear_buffer_dirty(bh);
496 nr_to_submit++;
497 } while ((bh = bh->b_this_page) != head);
498
499 /* Nothing to submit? Just unlock the folio... */
500 if (!nr_to_submit)
501 return 0;
502
503 bh = head = folio_buffers(folio);
504
505 /*
506 * If any blocks are being written to an encrypted file, encrypt them
507 * into a bounce page. For simplicity, just encrypt until the last
508 * block which might be needed. This may cause some unneeded blocks
509 * (e.g. holes) to be unnecessarily encrypted, but this is rare and
510 * can't happen in the common case of blocksize == PAGE_SIZE.
511 */
512 if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
513 gfp_t gfp_flags = GFP_NOFS;
514 unsigned int enc_bytes = round_up(len, i_blocksize(inode));
515 struct page *bounce_page;
516
517 /*
518 * Since bounce page allocation uses a mempool, we can only use
519 * a waiting mask (i.e. request guaranteed allocation) on the
520 * first page of the bio. Otherwise it can deadlock.
521 */
522 if (io->io_bio)
523 gfp_flags = GFP_NOWAIT | __GFP_NOWARN;
524 retry_encrypt:
525 bounce_page = fscrypt_encrypt_pagecache_blocks(&folio->page,
526 enc_bytes, 0, gfp_flags);
527 if (IS_ERR(bounce_page)) {
528 ret = PTR_ERR(bounce_page);
529 if (ret == -ENOMEM &&
530 (io->io_bio || wbc->sync_mode == WB_SYNC_ALL)) {
531 gfp_t new_gfp_flags = GFP_NOFS;
532 if (io->io_bio)
533 ext4_io_submit(io);
534 else
535 new_gfp_flags |= __GFP_NOFAIL;
536 memalloc_retry_wait(gfp_flags);
537 gfp_flags = new_gfp_flags;
538 goto retry_encrypt;
539 }
540
541 printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
542 folio_redirty_for_writepage(wbc, folio);
543 do {
544 if (buffer_async_write(bh)) {
545 clear_buffer_async_write(bh);
546 set_buffer_dirty(bh);
547 }
548 bh = bh->b_this_page;
549 } while (bh != head);
550
551 return ret;
552 }
553 io_folio = page_folio(bounce_page);
554 }
555
556 __folio_start_writeback(folio, keep_towrite);
557
558 /* Now submit buffers to write */
559 do {
560 if (!buffer_async_write(bh))
561 continue;
562 io_submit_add_bh(io, inode, folio, io_folio, bh);
563 } while ((bh = bh->b_this_page) != head);
564
565 return 0;
566}