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1// SPDX-License-Identifier: GPL-2.0
2#ifndef NO_BCACHEFS_FS
3
4#include "bcachefs.h"
5#include "alloc_foreground.h"
6#include "bkey_buf.h"
7#include "fs-io.h"
8#include "fs-io-buffered.h"
9#include "fs-io-direct.h"
10#include "fs-io-pagecache.h"
11#include "io_read.h"
12#include "io_write.h"
13
14#include <linux/backing-dev.h>
15#include <linux/pagemap.h>
16#include <linux/writeback.h>
17
18static inline bool bio_full(struct bio *bio, unsigned len)
19{
20 if (bio->bi_vcnt >= bio->bi_max_vecs)
21 return true;
22 if (bio->bi_iter.bi_size > UINT_MAX - len)
23 return true;
24 return false;
25}
26
27/* readpage(s): */
28
29static void bch2_readpages_end_io(struct bio *bio)
30{
31 struct folio_iter fi;
32
33 bio_for_each_folio_all(fi, bio) {
34 if (!bio->bi_status) {
35 folio_mark_uptodate(fi.folio);
36 } else {
37 folio_clear_uptodate(fi.folio);
38 folio_set_error(fi.folio);
39 }
40 folio_unlock(fi.folio);
41 }
42
43 bio_put(bio);
44}
45
46struct readpages_iter {
47 struct address_space *mapping;
48 unsigned idx;
49 folios folios;
50};
51
52static int readpages_iter_init(struct readpages_iter *iter,
53 struct readahead_control *ractl)
54{
55 struct folio *folio;
56
57 *iter = (struct readpages_iter) { ractl->mapping };
58
59 while ((folio = __readahead_folio(ractl))) {
60 if (!bch2_folio_create(folio, GFP_KERNEL) ||
61 darray_push(&iter->folios, folio)) {
62 bch2_folio_release(folio);
63 ractl->_nr_pages += folio_nr_pages(folio);
64 ractl->_index -= folio_nr_pages(folio);
65 return iter->folios.nr ? 0 : -ENOMEM;
66 }
67
68 folio_put(folio);
69 }
70
71 return 0;
72}
73
74static inline struct folio *readpage_iter_peek(struct readpages_iter *iter)
75{
76 if (iter->idx >= iter->folios.nr)
77 return NULL;
78 return iter->folios.data[iter->idx];
79}
80
81static inline void readpage_iter_advance(struct readpages_iter *iter)
82{
83 iter->idx++;
84}
85
86static bool extent_partial_reads_expensive(struct bkey_s_c k)
87{
88 struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
89 struct bch_extent_crc_unpacked crc;
90 const union bch_extent_entry *i;
91
92 bkey_for_each_crc(k.k, ptrs, crc, i)
93 if (crc.csum_type || crc.compression_type)
94 return true;
95 return false;
96}
97
98static int readpage_bio_extend(struct btree_trans *trans,
99 struct readpages_iter *iter,
100 struct bio *bio,
101 unsigned sectors_this_extent,
102 bool get_more)
103{
104 /* Don't hold btree locks while allocating memory: */
105 bch2_trans_unlock(trans);
106
107 while (bio_sectors(bio) < sectors_this_extent &&
108 bio->bi_vcnt < bio->bi_max_vecs) {
109 struct folio *folio = readpage_iter_peek(iter);
110 int ret;
111
112 if (folio) {
113 readpage_iter_advance(iter);
114 } else {
115 pgoff_t folio_offset = bio_end_sector(bio) >> PAGE_SECTORS_SHIFT;
116
117 if (!get_more)
118 break;
119
120 folio = xa_load(&iter->mapping->i_pages, folio_offset);
121 if (folio && !xa_is_value(folio))
122 break;
123
124 folio = filemap_alloc_folio(readahead_gfp_mask(iter->mapping), 0);
125 if (!folio)
126 break;
127
128 if (!__bch2_folio_create(folio, GFP_KERNEL)) {
129 folio_put(folio);
130 break;
131 }
132
133 ret = filemap_add_folio(iter->mapping, folio, folio_offset, GFP_KERNEL);
134 if (ret) {
135 __bch2_folio_release(folio);
136 folio_put(folio);
137 break;
138 }
139
140 folio_put(folio);
141 }
142
143 BUG_ON(folio_sector(folio) != bio_end_sector(bio));
144
145 BUG_ON(!bio_add_folio(bio, folio, folio_size(folio), 0));
146 }
147
148 return bch2_trans_relock(trans);
149}
150
151static void bchfs_read(struct btree_trans *trans,
152 struct bch_read_bio *rbio,
153 subvol_inum inum,
154 struct readpages_iter *readpages_iter)
155{
156 struct bch_fs *c = trans->c;
157 struct btree_iter iter;
158 struct bkey_buf sk;
159 int flags = BCH_READ_RETRY_IF_STALE|
160 BCH_READ_MAY_PROMOTE;
161 u32 snapshot;
162 int ret = 0;
163
164 rbio->c = c;
165 rbio->start_time = local_clock();
166 rbio->subvol = inum.subvol;
167
168 bch2_bkey_buf_init(&sk);
169retry:
170 bch2_trans_begin(trans);
171 iter = (struct btree_iter) { NULL };
172
173 ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
174 if (ret)
175 goto err;
176
177 bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
178 SPOS(inum.inum, rbio->bio.bi_iter.bi_sector, snapshot),
179 BTREE_ITER_SLOTS);
180 while (1) {
181 struct bkey_s_c k;
182 unsigned bytes, sectors, offset_into_extent;
183 enum btree_id data_btree = BTREE_ID_extents;
184
185 /*
186 * read_extent -> io_time_reset may cause a transaction restart
187 * without returning an error, we need to check for that here:
188 */
189 ret = bch2_trans_relock(trans);
190 if (ret)
191 break;
192
193 bch2_btree_iter_set_pos(&iter,
194 POS(inum.inum, rbio->bio.bi_iter.bi_sector));
195
196 k = bch2_btree_iter_peek_slot(&iter);
197 ret = bkey_err(k);
198 if (ret)
199 break;
200
201 offset_into_extent = iter.pos.offset -
202 bkey_start_offset(k.k);
203 sectors = k.k->size - offset_into_extent;
204
205 bch2_bkey_buf_reassemble(&sk, c, k);
206
207 ret = bch2_read_indirect_extent(trans, &data_btree,
208 &offset_into_extent, &sk);
209 if (ret)
210 break;
211
212 k = bkey_i_to_s_c(sk.k);
213
214 sectors = min(sectors, k.k->size - offset_into_extent);
215
216 if (readpages_iter) {
217 ret = readpage_bio_extend(trans, readpages_iter, &rbio->bio, sectors,
218 extent_partial_reads_expensive(k));
219 if (ret)
220 break;
221 }
222
223 bytes = min(sectors, bio_sectors(&rbio->bio)) << 9;
224 swap(rbio->bio.bi_iter.bi_size, bytes);
225
226 if (rbio->bio.bi_iter.bi_size == bytes)
227 flags |= BCH_READ_LAST_FRAGMENT;
228
229 bch2_bio_page_state_set(&rbio->bio, k);
230
231 bch2_read_extent(trans, rbio, iter.pos,
232 data_btree, k, offset_into_extent, flags);
233
234 if (flags & BCH_READ_LAST_FRAGMENT)
235 break;
236
237 swap(rbio->bio.bi_iter.bi_size, bytes);
238 bio_advance(&rbio->bio, bytes);
239
240 ret = btree_trans_too_many_iters(trans);
241 if (ret)
242 break;
243 }
244err:
245 bch2_trans_iter_exit(trans, &iter);
246
247 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
248 goto retry;
249
250 if (ret) {
251 bch_err_inum_offset_ratelimited(c,
252 iter.pos.inode,
253 iter.pos.offset << 9,
254 "read error %i from btree lookup", ret);
255 rbio->bio.bi_status = BLK_STS_IOERR;
256 bio_endio(&rbio->bio);
257 }
258
259 bch2_bkey_buf_exit(&sk, c);
260}
261
262void bch2_readahead(struct readahead_control *ractl)
263{
264 struct bch_inode_info *inode = to_bch_ei(ractl->mapping->host);
265 struct bch_fs *c = inode->v.i_sb->s_fs_info;
266 struct bch_io_opts opts;
267 struct btree_trans *trans = bch2_trans_get(c);
268 struct folio *folio;
269 struct readpages_iter readpages_iter;
270
271 bch2_inode_opts_get(&opts, c, &inode->ei_inode);
272
273 int ret = readpages_iter_init(&readpages_iter, ractl);
274 if (ret)
275 return;
276
277 bch2_pagecache_add_get(inode);
278
279 while ((folio = readpage_iter_peek(&readpages_iter))) {
280 unsigned n = min_t(unsigned,
281 readpages_iter.folios.nr -
282 readpages_iter.idx,
283 BIO_MAX_VECS);
284 struct bch_read_bio *rbio =
285 rbio_init(bio_alloc_bioset(NULL, n, REQ_OP_READ,
286 GFP_KERNEL, &c->bio_read),
287 opts);
288
289 readpage_iter_advance(&readpages_iter);
290
291 rbio->bio.bi_iter.bi_sector = folio_sector(folio);
292 rbio->bio.bi_end_io = bch2_readpages_end_io;
293 BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
294
295 bchfs_read(trans, rbio, inode_inum(inode),
296 &readpages_iter);
297 bch2_trans_unlock(trans);
298 }
299
300 bch2_pagecache_add_put(inode);
301
302 bch2_trans_put(trans);
303 darray_exit(&readpages_iter.folios);
304}
305
306static void bch2_read_single_folio_end_io(struct bio *bio)
307{
308 complete(bio->bi_private);
309}
310
311int bch2_read_single_folio(struct folio *folio, struct address_space *mapping)
312{
313 struct bch_inode_info *inode = to_bch_ei(mapping->host);
314 struct bch_fs *c = inode->v.i_sb->s_fs_info;
315 struct bch_read_bio *rbio;
316 struct bch_io_opts opts;
317 int ret;
318 DECLARE_COMPLETION_ONSTACK(done);
319
320 if (!bch2_folio_create(folio, GFP_KERNEL))
321 return -ENOMEM;
322
323 bch2_inode_opts_get(&opts, c, &inode->ei_inode);
324
325 rbio = rbio_init(bio_alloc_bioset(NULL, 1, REQ_OP_READ, GFP_KERNEL, &c->bio_read),
326 opts);
327 rbio->bio.bi_private = &done;
328 rbio->bio.bi_end_io = bch2_read_single_folio_end_io;
329
330 rbio->bio.bi_opf = REQ_OP_READ|REQ_SYNC;
331 rbio->bio.bi_iter.bi_sector = folio_sector(folio);
332 BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
333
334 bch2_trans_run(c, (bchfs_read(trans, rbio, inode_inum(inode), NULL), 0));
335 wait_for_completion(&done);
336
337 ret = blk_status_to_errno(rbio->bio.bi_status);
338 bio_put(&rbio->bio);
339
340 if (ret < 0)
341 return ret;
342
343 folio_mark_uptodate(folio);
344 return 0;
345}
346
347int bch2_read_folio(struct file *file, struct folio *folio)
348{
349 int ret;
350
351 ret = bch2_read_single_folio(folio, folio->mapping);
352 folio_unlock(folio);
353 return bch2_err_class(ret);
354}
355
356/* writepages: */
357
358struct bch_writepage_io {
359 struct bch_inode_info *inode;
360
361 /* must be last: */
362 struct bch_write_op op;
363};
364
365struct bch_writepage_state {
366 struct bch_writepage_io *io;
367 struct bch_io_opts opts;
368 struct bch_folio_sector *tmp;
369 unsigned tmp_sectors;
370};
371
372static inline struct bch_writepage_state bch_writepage_state_init(struct bch_fs *c,
373 struct bch_inode_info *inode)
374{
375 struct bch_writepage_state ret = { 0 };
376
377 bch2_inode_opts_get(&ret.opts, c, &inode->ei_inode);
378 return ret;
379}
380
381/*
382 * Determine when a writepage io is full. We have to limit writepage bios to a
383 * single page per bvec (i.e. 1MB with 4k pages) because that is the limit to
384 * what the bounce path in bch2_write_extent() can handle. In theory we could
385 * loosen this restriction for non-bounce I/O, but we don't have that context
386 * here. Ideally, we can up this limit and make it configurable in the future
387 * when the bounce path can be enhanced to accommodate larger source bios.
388 */
389static inline bool bch_io_full(struct bch_writepage_io *io, unsigned len)
390{
391 struct bio *bio = &io->op.wbio.bio;
392 return bio_full(bio, len) ||
393 (bio->bi_iter.bi_size + len > BIO_MAX_VECS * PAGE_SIZE);
394}
395
396static void bch2_writepage_io_done(struct bch_write_op *op)
397{
398 struct bch_writepage_io *io =
399 container_of(op, struct bch_writepage_io, op);
400 struct bch_fs *c = io->op.c;
401 struct bio *bio = &io->op.wbio.bio;
402 struct folio_iter fi;
403 unsigned i;
404
405 if (io->op.error) {
406 set_bit(EI_INODE_ERROR, &io->inode->ei_flags);
407
408 bio_for_each_folio_all(fi, bio) {
409 struct bch_folio *s;
410
411 folio_set_error(fi.folio);
412 mapping_set_error(fi.folio->mapping, -EIO);
413
414 s = __bch2_folio(fi.folio);
415 spin_lock(&s->lock);
416 for (i = 0; i < folio_sectors(fi.folio); i++)
417 s->s[i].nr_replicas = 0;
418 spin_unlock(&s->lock);
419 }
420 }
421
422 if (io->op.flags & BCH_WRITE_WROTE_DATA_INLINE) {
423 bio_for_each_folio_all(fi, bio) {
424 struct bch_folio *s;
425
426 s = __bch2_folio(fi.folio);
427 spin_lock(&s->lock);
428 for (i = 0; i < folio_sectors(fi.folio); i++)
429 s->s[i].nr_replicas = 0;
430 spin_unlock(&s->lock);
431 }
432 }
433
434 /*
435 * racing with fallocate can cause us to add fewer sectors than
436 * expected - but we shouldn't add more sectors than expected:
437 */
438 WARN_ON_ONCE(io->op.i_sectors_delta > 0);
439
440 /*
441 * (error (due to going RO) halfway through a page can screw that up
442 * slightly)
443 * XXX wtf?
444 BUG_ON(io->op.op.i_sectors_delta >= PAGE_SECTORS);
445 */
446
447 /*
448 * PageWriteback is effectively our ref on the inode - fixup i_blocks
449 * before calling end_page_writeback:
450 */
451 bch2_i_sectors_acct(c, io->inode, NULL, io->op.i_sectors_delta);
452
453 bio_for_each_folio_all(fi, bio) {
454 struct bch_folio *s = __bch2_folio(fi.folio);
455
456 if (atomic_dec_and_test(&s->write_count))
457 folio_end_writeback(fi.folio);
458 }
459
460 bio_put(&io->op.wbio.bio);
461}
462
463static void bch2_writepage_do_io(struct bch_writepage_state *w)
464{
465 struct bch_writepage_io *io = w->io;
466
467 w->io = NULL;
468 closure_call(&io->op.cl, bch2_write, NULL, NULL);
469}
470
471/*
472 * Get a bch_writepage_io and add @page to it - appending to an existing one if
473 * possible, else allocating a new one:
474 */
475static void bch2_writepage_io_alloc(struct bch_fs *c,
476 struct writeback_control *wbc,
477 struct bch_writepage_state *w,
478 struct bch_inode_info *inode,
479 u64 sector,
480 unsigned nr_replicas)
481{
482 struct bch_write_op *op;
483
484 w->io = container_of(bio_alloc_bioset(NULL, BIO_MAX_VECS,
485 REQ_OP_WRITE,
486 GFP_KERNEL,
487 &c->writepage_bioset),
488 struct bch_writepage_io, op.wbio.bio);
489
490 w->io->inode = inode;
491 op = &w->io->op;
492 bch2_write_op_init(op, c, w->opts);
493 op->target = w->opts.foreground_target;
494 op->nr_replicas = nr_replicas;
495 op->res.nr_replicas = nr_replicas;
496 op->write_point = writepoint_hashed(inode->ei_last_dirtied);
497 op->subvol = inode->ei_subvol;
498 op->pos = POS(inode->v.i_ino, sector);
499 op->end_io = bch2_writepage_io_done;
500 op->devs_need_flush = &inode->ei_devs_need_flush;
501 op->wbio.bio.bi_iter.bi_sector = sector;
502 op->wbio.bio.bi_opf = wbc_to_write_flags(wbc);
503}
504
505static int __bch2_writepage(struct folio *folio,
506 struct writeback_control *wbc,
507 void *data)
508{
509 struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
510 struct bch_fs *c = inode->v.i_sb->s_fs_info;
511 struct bch_writepage_state *w = data;
512 struct bch_folio *s;
513 unsigned i, offset, f_sectors, nr_replicas_this_write = U32_MAX;
514 loff_t i_size = i_size_read(&inode->v);
515 int ret;
516
517 EBUG_ON(!folio_test_uptodate(folio));
518
519 /* Is the folio fully inside i_size? */
520 if (folio_end_pos(folio) <= i_size)
521 goto do_io;
522
523 /* Is the folio fully outside i_size? (truncate in progress) */
524 if (folio_pos(folio) >= i_size) {
525 folio_unlock(folio);
526 return 0;
527 }
528
529 /*
530 * The folio straddles i_size. It must be zeroed out on each and every
531 * writepage invocation because it may be mmapped. "A file is mapped
532 * in multiples of the folio size. For a file that is not a multiple of
533 * the folio size, the remaining memory is zeroed when mapped, and
534 * writes to that region are not written out to the file."
535 */
536 folio_zero_segment(folio,
537 i_size - folio_pos(folio),
538 folio_size(folio));
539do_io:
540 f_sectors = folio_sectors(folio);
541 s = bch2_folio(folio);
542
543 if (f_sectors > w->tmp_sectors) {
544 kfree(w->tmp);
545 w->tmp = kcalloc(f_sectors, sizeof(struct bch_folio_sector), __GFP_NOFAIL);
546 w->tmp_sectors = f_sectors;
547 }
548
549 /*
550 * Things get really hairy with errors during writeback:
551 */
552 ret = bch2_get_folio_disk_reservation(c, inode, folio, false);
553 BUG_ON(ret);
554
555 /* Before unlocking the page, get copy of reservations: */
556 spin_lock(&s->lock);
557 memcpy(w->tmp, s->s, sizeof(struct bch_folio_sector) * f_sectors);
558
559 for (i = 0; i < f_sectors; i++) {
560 if (s->s[i].state < SECTOR_dirty)
561 continue;
562
563 nr_replicas_this_write =
564 min_t(unsigned, nr_replicas_this_write,
565 s->s[i].nr_replicas +
566 s->s[i].replicas_reserved);
567 }
568
569 for (i = 0; i < f_sectors; i++) {
570 if (s->s[i].state < SECTOR_dirty)
571 continue;
572
573 s->s[i].nr_replicas = w->opts.compression
574 ? 0 : nr_replicas_this_write;
575
576 s->s[i].replicas_reserved = 0;
577 bch2_folio_sector_set(folio, s, i, SECTOR_allocated);
578 }
579 spin_unlock(&s->lock);
580
581 BUG_ON(atomic_read(&s->write_count));
582 atomic_set(&s->write_count, 1);
583
584 BUG_ON(folio_test_writeback(folio));
585 folio_start_writeback(folio);
586
587 folio_unlock(folio);
588
589 offset = 0;
590 while (1) {
591 unsigned sectors = 0, dirty_sectors = 0, reserved_sectors = 0;
592 u64 sector;
593
594 while (offset < f_sectors &&
595 w->tmp[offset].state < SECTOR_dirty)
596 offset++;
597
598 if (offset == f_sectors)
599 break;
600
601 while (offset + sectors < f_sectors &&
602 w->tmp[offset + sectors].state >= SECTOR_dirty) {
603 reserved_sectors += w->tmp[offset + sectors].replicas_reserved;
604 dirty_sectors += w->tmp[offset + sectors].state == SECTOR_dirty;
605 sectors++;
606 }
607 BUG_ON(!sectors);
608
609 sector = folio_sector(folio) + offset;
610
611 if (w->io &&
612 (w->io->op.res.nr_replicas != nr_replicas_this_write ||
613 bch_io_full(w->io, sectors << 9) ||
614 bio_end_sector(&w->io->op.wbio.bio) != sector))
615 bch2_writepage_do_io(w);
616
617 if (!w->io)
618 bch2_writepage_io_alloc(c, wbc, w, inode, sector,
619 nr_replicas_this_write);
620
621 atomic_inc(&s->write_count);
622
623 BUG_ON(inode != w->io->inode);
624 BUG_ON(!bio_add_folio(&w->io->op.wbio.bio, folio,
625 sectors << 9, offset << 9));
626
627 /* Check for writing past i_size: */
628 WARN_ONCE((bio_end_sector(&w->io->op.wbio.bio) << 9) >
629 round_up(i_size, block_bytes(c)) &&
630 !test_bit(BCH_FS_emergency_ro, &c->flags),
631 "writing past i_size: %llu > %llu (unrounded %llu)\n",
632 bio_end_sector(&w->io->op.wbio.bio) << 9,
633 round_up(i_size, block_bytes(c)),
634 i_size);
635
636 w->io->op.res.sectors += reserved_sectors;
637 w->io->op.i_sectors_delta -= dirty_sectors;
638 w->io->op.new_i_size = i_size;
639
640 offset += sectors;
641 }
642
643 if (atomic_dec_and_test(&s->write_count))
644 folio_end_writeback(folio);
645
646 return 0;
647}
648
649int bch2_writepages(struct address_space *mapping, struct writeback_control *wbc)
650{
651 struct bch_fs *c = mapping->host->i_sb->s_fs_info;
652 struct bch_writepage_state w =
653 bch_writepage_state_init(c, to_bch_ei(mapping->host));
654 struct blk_plug plug;
655 int ret;
656
657 blk_start_plug(&plug);
658 ret = write_cache_pages(mapping, wbc, __bch2_writepage, &w);
659 if (w.io)
660 bch2_writepage_do_io(&w);
661 blk_finish_plug(&plug);
662 kfree(w.tmp);
663 return bch2_err_class(ret);
664}
665
666/* buffered writes: */
667
668int bch2_write_begin(struct file *file, struct address_space *mapping,
669 loff_t pos, unsigned len,
670 struct page **pagep, void **fsdata)
671{
672 struct bch_inode_info *inode = to_bch_ei(mapping->host);
673 struct bch_fs *c = inode->v.i_sb->s_fs_info;
674 struct bch2_folio_reservation *res;
675 struct folio *folio;
676 unsigned offset;
677 int ret = -ENOMEM;
678
679 res = kmalloc(sizeof(*res), GFP_KERNEL);
680 if (!res)
681 return -ENOMEM;
682
683 bch2_folio_reservation_init(c, inode, res);
684 *fsdata = res;
685
686 bch2_pagecache_add_get(inode);
687
688 folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT,
689 FGP_LOCK|FGP_WRITE|FGP_CREAT|FGP_STABLE,
690 mapping_gfp_mask(mapping));
691 if (IS_ERR_OR_NULL(folio))
692 goto err_unlock;
693
694 offset = pos - folio_pos(folio);
695 len = min_t(size_t, len, folio_end_pos(folio) - pos);
696
697 if (folio_test_uptodate(folio))
698 goto out;
699
700 /* If we're writing entire folio, don't need to read it in first: */
701 if (!offset && len == folio_size(folio))
702 goto out;
703
704 if (!offset && pos + len >= inode->v.i_size) {
705 folio_zero_segment(folio, len, folio_size(folio));
706 flush_dcache_folio(folio);
707 goto out;
708 }
709
710 if (folio_pos(folio) >= inode->v.i_size) {
711 folio_zero_segments(folio, 0, offset, offset + len, folio_size(folio));
712 flush_dcache_folio(folio);
713 goto out;
714 }
715readpage:
716 ret = bch2_read_single_folio(folio, mapping);
717 if (ret)
718 goto err;
719out:
720 ret = bch2_folio_set(c, inode_inum(inode), &folio, 1);
721 if (ret)
722 goto err;
723
724 ret = bch2_folio_reservation_get(c, inode, folio, res, offset, len);
725 if (ret) {
726 if (!folio_test_uptodate(folio)) {
727 /*
728 * If the folio hasn't been read in, we won't know if we
729 * actually need a reservation - we don't actually need
730 * to read here, we just need to check if the folio is
731 * fully backed by uncompressed data:
732 */
733 goto readpage;
734 }
735
736 goto err;
737 }
738
739 *pagep = &folio->page;
740 return 0;
741err:
742 folio_unlock(folio);
743 folio_put(folio);
744 *pagep = NULL;
745err_unlock:
746 bch2_pagecache_add_put(inode);
747 kfree(res);
748 *fsdata = NULL;
749 return bch2_err_class(ret);
750}
751
752int bch2_write_end(struct file *file, struct address_space *mapping,
753 loff_t pos, unsigned len, unsigned copied,
754 struct page *page, void *fsdata)
755{
756 struct bch_inode_info *inode = to_bch_ei(mapping->host);
757 struct bch_fs *c = inode->v.i_sb->s_fs_info;
758 struct bch2_folio_reservation *res = fsdata;
759 struct folio *folio = page_folio(page);
760 unsigned offset = pos - folio_pos(folio);
761
762 lockdep_assert_held(&inode->v.i_rwsem);
763 BUG_ON(offset + copied > folio_size(folio));
764
765 if (unlikely(copied < len && !folio_test_uptodate(folio))) {
766 /*
767 * The folio needs to be read in, but that would destroy
768 * our partial write - simplest thing is to just force
769 * userspace to redo the write:
770 */
771 folio_zero_range(folio, 0, folio_size(folio));
772 flush_dcache_folio(folio);
773 copied = 0;
774 }
775
776 spin_lock(&inode->v.i_lock);
777 if (pos + copied > inode->v.i_size)
778 i_size_write(&inode->v, pos + copied);
779 spin_unlock(&inode->v.i_lock);
780
781 if (copied) {
782 if (!folio_test_uptodate(folio))
783 folio_mark_uptodate(folio);
784
785 bch2_set_folio_dirty(c, inode, folio, res, offset, copied);
786
787 inode->ei_last_dirtied = (unsigned long) current;
788 }
789
790 folio_unlock(folio);
791 folio_put(folio);
792 bch2_pagecache_add_put(inode);
793
794 bch2_folio_reservation_put(c, inode, res);
795 kfree(res);
796
797 return copied;
798}
799
800static noinline void folios_trunc(folios *fs, struct folio **fi)
801{
802 while (fs->data + fs->nr > fi) {
803 struct folio *f = darray_pop(fs);
804
805 folio_unlock(f);
806 folio_put(f);
807 }
808}
809
810static int __bch2_buffered_write(struct bch_inode_info *inode,
811 struct address_space *mapping,
812 struct iov_iter *iter,
813 loff_t pos, unsigned len)
814{
815 struct bch_fs *c = inode->v.i_sb->s_fs_info;
816 struct bch2_folio_reservation res;
817 folios fs;
818 struct folio *f;
819 unsigned copied = 0, f_offset, f_copied;
820 u64 end = pos + len, f_pos, f_len;
821 loff_t last_folio_pos = inode->v.i_size;
822 int ret = 0;
823
824 BUG_ON(!len);
825
826 bch2_folio_reservation_init(c, inode, &res);
827 darray_init(&fs);
828
829 ret = bch2_filemap_get_contig_folios_d(mapping, pos, end,
830 FGP_LOCK|FGP_WRITE|FGP_STABLE|FGP_CREAT,
831 mapping_gfp_mask(mapping),
832 &fs);
833 if (ret)
834 goto out;
835
836 BUG_ON(!fs.nr);
837
838 f = darray_first(fs);
839 if (pos != folio_pos(f) && !folio_test_uptodate(f)) {
840 ret = bch2_read_single_folio(f, mapping);
841 if (ret)
842 goto out;
843 }
844
845 f = darray_last(fs);
846 end = min(end, folio_end_pos(f));
847 last_folio_pos = folio_pos(f);
848 if (end != folio_end_pos(f) && !folio_test_uptodate(f)) {
849 if (end >= inode->v.i_size) {
850 folio_zero_range(f, 0, folio_size(f));
851 } else {
852 ret = bch2_read_single_folio(f, mapping);
853 if (ret)
854 goto out;
855 }
856 }
857
858 ret = bch2_folio_set(c, inode_inum(inode), fs.data, fs.nr);
859 if (ret)
860 goto out;
861
862 f_pos = pos;
863 f_offset = pos - folio_pos(darray_first(fs));
864 darray_for_each(fs, fi) {
865 f = *fi;
866 f_len = min(end, folio_end_pos(f)) - f_pos;
867
868 /*
869 * XXX: per POSIX and fstests generic/275, on -ENOSPC we're
870 * supposed to write as much as we have disk space for.
871 *
872 * On failure here we should still write out a partial page if
873 * we aren't completely out of disk space - we don't do that
874 * yet:
875 */
876 ret = bch2_folio_reservation_get(c, inode, f, &res, f_offset, f_len);
877 if (unlikely(ret)) {
878 folios_trunc(&fs, fi);
879 if (!fs.nr)
880 goto out;
881
882 end = min(end, folio_end_pos(darray_last(fs)));
883 break;
884 }
885
886 f_pos = folio_end_pos(f);
887 f_offset = 0;
888 }
889
890 if (mapping_writably_mapped(mapping))
891 darray_for_each(fs, fi)
892 flush_dcache_folio(*fi);
893
894 f_pos = pos;
895 f_offset = pos - folio_pos(darray_first(fs));
896 darray_for_each(fs, fi) {
897 f = *fi;
898 f_len = min(end, folio_end_pos(f)) - f_pos;
899 f_copied = copy_page_from_iter_atomic(&f->page, f_offset, f_len, iter);
900 if (!f_copied) {
901 folios_trunc(&fs, fi);
902 break;
903 }
904
905 if (!folio_test_uptodate(f) &&
906 f_copied != folio_size(f) &&
907 pos + copied + f_copied < inode->v.i_size) {
908 iov_iter_revert(iter, f_copied);
909 folio_zero_range(f, 0, folio_size(f));
910 folios_trunc(&fs, fi);
911 break;
912 }
913
914 flush_dcache_folio(f);
915 copied += f_copied;
916
917 if (f_copied != f_len) {
918 folios_trunc(&fs, fi + 1);
919 break;
920 }
921
922 f_pos = folio_end_pos(f);
923 f_offset = 0;
924 }
925
926 if (!copied)
927 goto out;
928
929 end = pos + copied;
930
931 spin_lock(&inode->v.i_lock);
932 if (end > inode->v.i_size)
933 i_size_write(&inode->v, end);
934 spin_unlock(&inode->v.i_lock);
935
936 f_pos = pos;
937 f_offset = pos - folio_pos(darray_first(fs));
938 darray_for_each(fs, fi) {
939 f = *fi;
940 f_len = min(end, folio_end_pos(f)) - f_pos;
941
942 if (!folio_test_uptodate(f))
943 folio_mark_uptodate(f);
944
945 bch2_set_folio_dirty(c, inode, f, &res, f_offset, f_len);
946
947 f_pos = folio_end_pos(f);
948 f_offset = 0;
949 }
950
951 inode->ei_last_dirtied = (unsigned long) current;
952out:
953 darray_for_each(fs, fi) {
954 folio_unlock(*fi);
955 folio_put(*fi);
956 }
957
958 /*
959 * If the last folio added to the mapping starts beyond current EOF, we
960 * performed a short write but left around at least one post-EOF folio.
961 * Clean up the mapping before we return.
962 */
963 if (last_folio_pos >= inode->v.i_size)
964 truncate_pagecache(&inode->v, inode->v.i_size);
965
966 darray_exit(&fs);
967 bch2_folio_reservation_put(c, inode, &res);
968
969 return copied ?: ret;
970}
971
972static ssize_t bch2_buffered_write(struct kiocb *iocb, struct iov_iter *iter)
973{
974 struct file *file = iocb->ki_filp;
975 struct address_space *mapping = file->f_mapping;
976 struct bch_inode_info *inode = file_bch_inode(file);
977 loff_t pos = iocb->ki_pos;
978 ssize_t written = 0;
979 int ret = 0;
980
981 bch2_pagecache_add_get(inode);
982
983 do {
984 unsigned offset = pos & (PAGE_SIZE - 1);
985 unsigned bytes = iov_iter_count(iter);
986again:
987 /*
988 * Bring in the user page that we will copy from _first_.
989 * Otherwise there's a nasty deadlock on copying from the
990 * same page as we're writing to, without it being marked
991 * up-to-date.
992 *
993 * Not only is this an optimisation, but it is also required
994 * to check that the address is actually valid, when atomic
995 * usercopies are used, below.
996 */
997 if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
998 bytes = min_t(unsigned long, iov_iter_count(iter),
999 PAGE_SIZE - offset);
1000
1001 if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
1002 ret = -EFAULT;
1003 break;
1004 }
1005 }
1006
1007 if (unlikely(fatal_signal_pending(current))) {
1008 ret = -EINTR;
1009 break;
1010 }
1011
1012 ret = __bch2_buffered_write(inode, mapping, iter, pos, bytes);
1013 if (unlikely(ret < 0))
1014 break;
1015
1016 cond_resched();
1017
1018 if (unlikely(ret == 0)) {
1019 /*
1020 * If we were unable to copy any data at all, we must
1021 * fall back to a single segment length write.
1022 *
1023 * If we didn't fallback here, we could livelock
1024 * because not all segments in the iov can be copied at
1025 * once without a pagefault.
1026 */
1027 bytes = min_t(unsigned long, PAGE_SIZE - offset,
1028 iov_iter_single_seg_count(iter));
1029 goto again;
1030 }
1031 pos += ret;
1032 written += ret;
1033 ret = 0;
1034
1035 balance_dirty_pages_ratelimited(mapping);
1036 } while (iov_iter_count(iter));
1037
1038 bch2_pagecache_add_put(inode);
1039
1040 return written ? written : ret;
1041}
1042
1043ssize_t bch2_write_iter(struct kiocb *iocb, struct iov_iter *from)
1044{
1045 struct file *file = iocb->ki_filp;
1046 struct bch_inode_info *inode = file_bch_inode(file);
1047 ssize_t ret;
1048
1049 if (iocb->ki_flags & IOCB_DIRECT) {
1050 ret = bch2_direct_write(iocb, from);
1051 goto out;
1052 }
1053
1054 inode_lock(&inode->v);
1055
1056 ret = generic_write_checks(iocb, from);
1057 if (ret <= 0)
1058 goto unlock;
1059
1060 ret = file_remove_privs(file);
1061 if (ret)
1062 goto unlock;
1063
1064 ret = file_update_time(file);
1065 if (ret)
1066 goto unlock;
1067
1068 ret = bch2_buffered_write(iocb, from);
1069 if (likely(ret > 0))
1070 iocb->ki_pos += ret;
1071unlock:
1072 inode_unlock(&inode->v);
1073
1074 if (ret > 0)
1075 ret = generic_write_sync(iocb, ret);
1076out:
1077 return bch2_err_class(ret);
1078}
1079
1080void bch2_fs_fs_io_buffered_exit(struct bch_fs *c)
1081{
1082 bioset_exit(&c->writepage_bioset);
1083}
1084
1085int bch2_fs_fs_io_buffered_init(struct bch_fs *c)
1086{
1087 if (bioset_init(&c->writepage_bioset,
1088 4, offsetof(struct bch_writepage_io, op.wbio.bio),
1089 BIOSET_NEED_BVECS))
1090 return -BCH_ERR_ENOMEM_writepage_bioset_init;
1091
1092 return 0;
1093}
1094
1095#endif /* NO_BCACHEFS_FS */