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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 "fs.h"
7#include "fs-io.h"
8#include "fs-io-direct.h"
9#include "fs-io-pagecache.h"
10#include "io_read.h"
11#include "io_write.h"
12
13#include <linux/kthread.h>
14#include <linux/pagemap.h>
15#include <linux/prefetch.h>
16#include <linux/task_io_accounting_ops.h>
17
18/* O_DIRECT reads */
19
20struct dio_read {
21 struct closure cl;
22 struct kiocb *req;
23 long ret;
24 bool should_dirty;
25 struct bch_read_bio rbio;
26};
27
28static void bio_check_or_release(struct bio *bio, bool check_dirty)
29{
30 if (check_dirty) {
31 bio_check_pages_dirty(bio);
32 } else {
33 bio_release_pages(bio, false);
34 bio_put(bio);
35 }
36}
37
38static CLOSURE_CALLBACK(bch2_dio_read_complete)
39{
40 closure_type(dio, struct dio_read, cl);
41
42 dio->req->ki_complete(dio->req, dio->ret);
43 bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
44}
45
46static void bch2_direct_IO_read_endio(struct bio *bio)
47{
48 struct dio_read *dio = bio->bi_private;
49
50 if (bio->bi_status)
51 dio->ret = blk_status_to_errno(bio->bi_status);
52
53 closure_put(&dio->cl);
54}
55
56static void bch2_direct_IO_read_split_endio(struct bio *bio)
57{
58 struct dio_read *dio = bio->bi_private;
59 bool should_dirty = dio->should_dirty;
60
61 bch2_direct_IO_read_endio(bio);
62 bio_check_or_release(bio, should_dirty);
63}
64
65static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter)
66{
67 struct file *file = req->ki_filp;
68 struct bch_inode_info *inode = file_bch_inode(file);
69 struct bch_fs *c = inode->v.i_sb->s_fs_info;
70 struct bch_io_opts opts;
71 struct dio_read *dio;
72 struct bio *bio;
73 loff_t offset = req->ki_pos;
74 bool sync = is_sync_kiocb(req);
75 size_t shorten;
76 ssize_t ret;
77
78 bch2_inode_opts_get(&opts, c, &inode->ei_inode);
79
80 /* bios must be 512 byte aligned: */
81 if ((offset|iter->count) & (SECTOR_SIZE - 1))
82 return -EINVAL;
83
84 ret = min_t(loff_t, iter->count,
85 max_t(loff_t, 0, i_size_read(&inode->v) - offset));
86
87 if (!ret)
88 return ret;
89
90 shorten = iov_iter_count(iter) - round_up(ret, block_bytes(c));
91 if (shorten >= iter->count)
92 shorten = 0;
93 iter->count -= shorten;
94
95 bio = bio_alloc_bioset(NULL,
96 bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
97 REQ_OP_READ,
98 GFP_KERNEL,
99 &c->dio_read_bioset);
100
101 bio->bi_end_io = bch2_direct_IO_read_endio;
102
103 dio = container_of(bio, struct dio_read, rbio.bio);
104 closure_init(&dio->cl, NULL);
105
106 /*
107 * this is a _really_ horrible hack just to avoid an atomic sub at the
108 * end:
109 */
110 if (!sync) {
111 set_closure_fn(&dio->cl, bch2_dio_read_complete, NULL);
112 atomic_set(&dio->cl.remaining,
113 CLOSURE_REMAINING_INITIALIZER -
114 CLOSURE_RUNNING +
115 CLOSURE_DESTRUCTOR);
116 } else {
117 atomic_set(&dio->cl.remaining,
118 CLOSURE_REMAINING_INITIALIZER + 1);
119 dio->cl.closure_get_happened = true;
120 }
121
122 dio->req = req;
123 dio->ret = ret;
124 /*
125 * This is one of the sketchier things I've encountered: we have to skip
126 * the dirtying of requests that are internal from the kernel (i.e. from
127 * loopback), because we'll deadlock on page_lock.
128 */
129 dio->should_dirty = iter_is_iovec(iter);
130
131 goto start;
132 while (iter->count) {
133 bio = bio_alloc_bioset(NULL,
134 bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
135 REQ_OP_READ,
136 GFP_KERNEL,
137 &c->bio_read);
138 bio->bi_end_io = bch2_direct_IO_read_split_endio;
139start:
140 bio->bi_opf = REQ_OP_READ|REQ_SYNC;
141 bio->bi_iter.bi_sector = offset >> 9;
142 bio->bi_private = dio;
143
144 ret = bio_iov_iter_get_pages(bio, iter);
145 if (ret < 0) {
146 /* XXX: fault inject this path */
147 bio->bi_status = BLK_STS_RESOURCE;
148 bio_endio(bio);
149 break;
150 }
151
152 offset += bio->bi_iter.bi_size;
153
154 if (dio->should_dirty)
155 bio_set_pages_dirty(bio);
156
157 if (iter->count)
158 closure_get(&dio->cl);
159
160 bch2_read(c, rbio_init(bio, opts), inode_inum(inode));
161 }
162
163 iter->count += shorten;
164
165 if (sync) {
166 closure_sync(&dio->cl);
167 closure_debug_destroy(&dio->cl);
168 ret = dio->ret;
169 bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
170 return ret;
171 } else {
172 return -EIOCBQUEUED;
173 }
174}
175
176ssize_t bch2_read_iter(struct kiocb *iocb, struct iov_iter *iter)
177{
178 struct file *file = iocb->ki_filp;
179 struct bch_inode_info *inode = file_bch_inode(file);
180 struct address_space *mapping = file->f_mapping;
181 size_t count = iov_iter_count(iter);
182 ssize_t ret;
183
184 if (!count)
185 return 0; /* skip atime */
186
187 if (iocb->ki_flags & IOCB_DIRECT) {
188 struct blk_plug plug;
189
190 if (unlikely(mapping->nrpages)) {
191 ret = filemap_write_and_wait_range(mapping,
192 iocb->ki_pos,
193 iocb->ki_pos + count - 1);
194 if (ret < 0)
195 goto out;
196 }
197
198 file_accessed(file);
199
200 blk_start_plug(&plug);
201 ret = bch2_direct_IO_read(iocb, iter);
202 blk_finish_plug(&plug);
203
204 if (ret >= 0)
205 iocb->ki_pos += ret;
206 } else {
207 bch2_pagecache_add_get(inode);
208 ret = generic_file_read_iter(iocb, iter);
209 bch2_pagecache_add_put(inode);
210 }
211out:
212 return bch2_err_class(ret);
213}
214
215/* O_DIRECT writes */
216
217struct dio_write {
218 struct kiocb *req;
219 struct address_space *mapping;
220 struct bch_inode_info *inode;
221 struct mm_struct *mm;
222 const struct iovec *iov;
223 unsigned loop:1,
224 extending:1,
225 sync:1,
226 flush:1;
227 struct quota_res quota_res;
228 u64 written;
229
230 struct iov_iter iter;
231 struct iovec inline_vecs[2];
232
233 /* must be last: */
234 struct bch_write_op op;
235};
236
237static bool bch2_check_range_allocated(struct bch_fs *c, subvol_inum inum,
238 u64 offset, u64 size,
239 unsigned nr_replicas, bool compressed)
240{
241 struct btree_trans *trans = bch2_trans_get(c);
242 struct btree_iter iter;
243 struct bkey_s_c k;
244 u64 end = offset + size;
245 u32 snapshot;
246 bool ret = true;
247 int err;
248retry:
249 bch2_trans_begin(trans);
250
251 err = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
252 if (err)
253 goto err;
254
255 for_each_btree_key_norestart(trans, iter, BTREE_ID_extents,
256 SPOS(inum.inum, offset, snapshot),
257 BTREE_ITER_SLOTS, k, err) {
258 if (bkey_ge(bkey_start_pos(k.k), POS(inum.inum, end)))
259 break;
260
261 if (k.k->p.snapshot != snapshot ||
262 nr_replicas > bch2_bkey_replicas(c, k) ||
263 (!compressed && bch2_bkey_sectors_compressed(k))) {
264 ret = false;
265 break;
266 }
267 }
268
269 offset = iter.pos.offset;
270 bch2_trans_iter_exit(trans, &iter);
271err:
272 if (bch2_err_matches(err, BCH_ERR_transaction_restart))
273 goto retry;
274 bch2_trans_put(trans);
275
276 return err ? false : ret;
277}
278
279static noinline bool bch2_dio_write_check_allocated(struct dio_write *dio)
280{
281 struct bch_fs *c = dio->op.c;
282 struct bch_inode_info *inode = dio->inode;
283 struct bio *bio = &dio->op.wbio.bio;
284
285 return bch2_check_range_allocated(c, inode_inum(inode),
286 dio->op.pos.offset, bio_sectors(bio),
287 dio->op.opts.data_replicas,
288 dio->op.opts.compression != 0);
289}
290
291static void bch2_dio_write_loop_async(struct bch_write_op *);
292static __always_inline long bch2_dio_write_done(struct dio_write *dio);
293
294/*
295 * We're going to return -EIOCBQUEUED, but we haven't finished consuming the
296 * iov_iter yet, so we need to stash a copy of the iovec: it might be on the
297 * caller's stack, we're not guaranteed that it will live for the duration of
298 * the IO:
299 */
300static noinline int bch2_dio_write_copy_iov(struct dio_write *dio)
301{
302 struct iovec *iov = dio->inline_vecs;
303
304 /*
305 * iov_iter has a single embedded iovec - nothing to do:
306 */
307 if (iter_is_ubuf(&dio->iter))
308 return 0;
309
310 /*
311 * We don't currently handle non-iovec iov_iters here - return an error,
312 * and we'll fall back to doing the IO synchronously:
313 */
314 if (!iter_is_iovec(&dio->iter))
315 return -1;
316
317 if (dio->iter.nr_segs > ARRAY_SIZE(dio->inline_vecs)) {
318 dio->iov = iov = kmalloc_array(dio->iter.nr_segs, sizeof(*iov),
319 GFP_KERNEL);
320 if (unlikely(!iov))
321 return -ENOMEM;
322 }
323
324 memcpy(iov, dio->iter.__iov, dio->iter.nr_segs * sizeof(*iov));
325 dio->iter.__iov = iov;
326 return 0;
327}
328
329static CLOSURE_CALLBACK(bch2_dio_write_flush_done)
330{
331 closure_type(dio, struct dio_write, op.cl);
332 struct bch_fs *c = dio->op.c;
333
334 closure_debug_destroy(cl);
335
336 dio->op.error = bch2_journal_error(&c->journal);
337
338 bch2_dio_write_done(dio);
339}
340
341static noinline void bch2_dio_write_flush(struct dio_write *dio)
342{
343 struct bch_fs *c = dio->op.c;
344 struct bch_inode_unpacked inode;
345 int ret;
346
347 dio->flush = 0;
348
349 closure_init(&dio->op.cl, NULL);
350
351 if (!dio->op.error) {
352 ret = bch2_inode_find_by_inum(c, inode_inum(dio->inode), &inode);
353 if (ret) {
354 dio->op.error = ret;
355 } else {
356 bch2_journal_flush_seq_async(&c->journal, inode.bi_journal_seq,
357 &dio->op.cl);
358 bch2_inode_flush_nocow_writes_async(c, dio->inode, &dio->op.cl);
359 }
360 }
361
362 if (dio->sync) {
363 closure_sync(&dio->op.cl);
364 closure_debug_destroy(&dio->op.cl);
365 } else {
366 continue_at(&dio->op.cl, bch2_dio_write_flush_done, NULL);
367 }
368}
369
370static __always_inline long bch2_dio_write_done(struct dio_write *dio)
371{
372 struct kiocb *req = dio->req;
373 struct bch_inode_info *inode = dio->inode;
374 bool sync = dio->sync;
375 long ret;
376
377 if (unlikely(dio->flush)) {
378 bch2_dio_write_flush(dio);
379 if (!sync)
380 return -EIOCBQUEUED;
381 }
382
383 bch2_pagecache_block_put(inode);
384
385 kfree(dio->iov);
386
387 ret = dio->op.error ?: ((long) dio->written << 9);
388 bio_put(&dio->op.wbio.bio);
389
390 /* inode->i_dio_count is our ref on inode and thus bch_fs */
391 inode_dio_end(&inode->v);
392
393 if (ret < 0)
394 ret = bch2_err_class(ret);
395
396 if (!sync) {
397 req->ki_complete(req, ret);
398 ret = -EIOCBQUEUED;
399 }
400 return ret;
401}
402
403static __always_inline void bch2_dio_write_end(struct dio_write *dio)
404{
405 struct bch_fs *c = dio->op.c;
406 struct kiocb *req = dio->req;
407 struct bch_inode_info *inode = dio->inode;
408 struct bio *bio = &dio->op.wbio.bio;
409
410 req->ki_pos += (u64) dio->op.written << 9;
411 dio->written += dio->op.written;
412
413 if (dio->extending) {
414 spin_lock(&inode->v.i_lock);
415 if (req->ki_pos > inode->v.i_size)
416 i_size_write(&inode->v, req->ki_pos);
417 spin_unlock(&inode->v.i_lock);
418 }
419
420 if (dio->op.i_sectors_delta || dio->quota_res.sectors) {
421 mutex_lock(&inode->ei_quota_lock);
422 __bch2_i_sectors_acct(c, inode, &dio->quota_res, dio->op.i_sectors_delta);
423 __bch2_quota_reservation_put(c, inode, &dio->quota_res);
424 mutex_unlock(&inode->ei_quota_lock);
425 }
426
427 bio_release_pages(bio, false);
428
429 if (unlikely(dio->op.error))
430 set_bit(EI_INODE_ERROR, &inode->ei_flags);
431}
432
433static __always_inline long bch2_dio_write_loop(struct dio_write *dio)
434{
435 struct bch_fs *c = dio->op.c;
436 struct kiocb *req = dio->req;
437 struct address_space *mapping = dio->mapping;
438 struct bch_inode_info *inode = dio->inode;
439 struct bch_io_opts opts;
440 struct bio *bio = &dio->op.wbio.bio;
441 unsigned unaligned, iter_count;
442 bool sync = dio->sync, dropped_locks;
443 long ret;
444
445 bch2_inode_opts_get(&opts, c, &inode->ei_inode);
446
447 while (1) {
448 iter_count = dio->iter.count;
449
450 EBUG_ON(current->faults_disabled_mapping);
451 current->faults_disabled_mapping = mapping;
452
453 ret = bio_iov_iter_get_pages(bio, &dio->iter);
454
455 dropped_locks = fdm_dropped_locks();
456
457 current->faults_disabled_mapping = NULL;
458
459 /*
460 * If the fault handler returned an error but also signalled
461 * that it dropped & retook ei_pagecache_lock, we just need to
462 * re-shoot down the page cache and retry:
463 */
464 if (dropped_locks && ret)
465 ret = 0;
466
467 if (unlikely(ret < 0))
468 goto err;
469
470 if (unlikely(dropped_locks)) {
471 ret = bch2_write_invalidate_inode_pages_range(mapping,
472 req->ki_pos,
473 req->ki_pos + iter_count - 1);
474 if (unlikely(ret))
475 goto err;
476
477 if (!bio->bi_iter.bi_size)
478 continue;
479 }
480
481 unaligned = bio->bi_iter.bi_size & (block_bytes(c) - 1);
482 bio->bi_iter.bi_size -= unaligned;
483 iov_iter_revert(&dio->iter, unaligned);
484
485 if (!bio->bi_iter.bi_size) {
486 /*
487 * bio_iov_iter_get_pages was only able to get <
488 * blocksize worth of pages:
489 */
490 ret = -EFAULT;
491 goto err;
492 }
493
494 bch2_write_op_init(&dio->op, c, opts);
495 dio->op.end_io = sync
496 ? NULL
497 : bch2_dio_write_loop_async;
498 dio->op.target = dio->op.opts.foreground_target;
499 dio->op.write_point = writepoint_hashed((unsigned long) current);
500 dio->op.nr_replicas = dio->op.opts.data_replicas;
501 dio->op.subvol = inode->ei_subvol;
502 dio->op.pos = POS(inode->v.i_ino, (u64) req->ki_pos >> 9);
503 dio->op.devs_need_flush = &inode->ei_devs_need_flush;
504
505 if (sync)
506 dio->op.flags |= BCH_WRITE_SYNC;
507 dio->op.flags |= BCH_WRITE_CHECK_ENOSPC;
508
509 ret = bch2_quota_reservation_add(c, inode, &dio->quota_res,
510 bio_sectors(bio), true);
511 if (unlikely(ret))
512 goto err;
513
514 ret = bch2_disk_reservation_get(c, &dio->op.res, bio_sectors(bio),
515 dio->op.opts.data_replicas, 0);
516 if (unlikely(ret) &&
517 !bch2_dio_write_check_allocated(dio))
518 goto err;
519
520 task_io_account_write(bio->bi_iter.bi_size);
521
522 if (unlikely(dio->iter.count) &&
523 !dio->sync &&
524 !dio->loop &&
525 bch2_dio_write_copy_iov(dio))
526 dio->sync = sync = true;
527
528 dio->loop = true;
529 closure_call(&dio->op.cl, bch2_write, NULL, NULL);
530
531 if (!sync)
532 return -EIOCBQUEUED;
533
534 bch2_dio_write_end(dio);
535
536 if (likely(!dio->iter.count) || dio->op.error)
537 break;
538
539 bio_reset(bio, NULL, REQ_OP_WRITE);
540 }
541out:
542 return bch2_dio_write_done(dio);
543err:
544 dio->op.error = ret;
545
546 bio_release_pages(bio, false);
547
548 bch2_quota_reservation_put(c, inode, &dio->quota_res);
549 goto out;
550}
551
552static noinline __cold void bch2_dio_write_continue(struct dio_write *dio)
553{
554 struct mm_struct *mm = dio->mm;
555
556 bio_reset(&dio->op.wbio.bio, NULL, REQ_OP_WRITE);
557
558 if (mm)
559 kthread_use_mm(mm);
560 bch2_dio_write_loop(dio);
561 if (mm)
562 kthread_unuse_mm(mm);
563}
564
565static void bch2_dio_write_loop_async(struct bch_write_op *op)
566{
567 struct dio_write *dio = container_of(op, struct dio_write, op);
568
569 bch2_dio_write_end(dio);
570
571 if (likely(!dio->iter.count) || dio->op.error)
572 bch2_dio_write_done(dio);
573 else
574 bch2_dio_write_continue(dio);
575}
576
577ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
578{
579 struct file *file = req->ki_filp;
580 struct address_space *mapping = file->f_mapping;
581 struct bch_inode_info *inode = file_bch_inode(file);
582 struct bch_fs *c = inode->v.i_sb->s_fs_info;
583 struct dio_write *dio;
584 struct bio *bio;
585 bool locked = true, extending;
586 ssize_t ret;
587
588 prefetch(&c->opts);
589 prefetch((void *) &c->opts + 64);
590 prefetch(&inode->ei_inode);
591 prefetch((void *) &inode->ei_inode + 64);
592
593 inode_lock(&inode->v);
594
595 ret = generic_write_checks(req, iter);
596 if (unlikely(ret <= 0))
597 goto err;
598
599 ret = file_remove_privs(file);
600 if (unlikely(ret))
601 goto err;
602
603 ret = file_update_time(file);
604 if (unlikely(ret))
605 goto err;
606
607 if (unlikely((req->ki_pos|iter->count) & (block_bytes(c) - 1)))
608 goto err;
609
610 inode_dio_begin(&inode->v);
611 bch2_pagecache_block_get(inode);
612
613 extending = req->ki_pos + iter->count > inode->v.i_size;
614 if (!extending) {
615 inode_unlock(&inode->v);
616 locked = false;
617 }
618
619 bio = bio_alloc_bioset(NULL,
620 bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
621 REQ_OP_WRITE,
622 GFP_KERNEL,
623 &c->dio_write_bioset);
624 dio = container_of(bio, struct dio_write, op.wbio.bio);
625 dio->req = req;
626 dio->mapping = mapping;
627 dio->inode = inode;
628 dio->mm = current->mm;
629 dio->iov = NULL;
630 dio->loop = false;
631 dio->extending = extending;
632 dio->sync = is_sync_kiocb(req) || extending;
633 dio->flush = iocb_is_dsync(req) && !c->opts.journal_flush_disabled;
634 dio->quota_res.sectors = 0;
635 dio->written = 0;
636 dio->iter = *iter;
637 dio->op.c = c;
638
639 if (unlikely(mapping->nrpages)) {
640 ret = bch2_write_invalidate_inode_pages_range(mapping,
641 req->ki_pos,
642 req->ki_pos + iter->count - 1);
643 if (unlikely(ret))
644 goto err_put_bio;
645 }
646
647 ret = bch2_dio_write_loop(dio);
648err:
649 if (locked)
650 inode_unlock(&inode->v);
651 return ret;
652err_put_bio:
653 bch2_pagecache_block_put(inode);
654 bio_put(bio);
655 inode_dio_end(&inode->v);
656 goto err;
657}
658
659void bch2_fs_fs_io_direct_exit(struct bch_fs *c)
660{
661 bioset_exit(&c->dio_write_bioset);
662 bioset_exit(&c->dio_read_bioset);
663}
664
665int bch2_fs_fs_io_direct_init(struct bch_fs *c)
666{
667 if (bioset_init(&c->dio_read_bioset,
668 4, offsetof(struct dio_read, rbio.bio),
669 BIOSET_NEED_BVECS))
670 return -BCH_ERR_ENOMEM_dio_read_bioset_init;
671
672 if (bioset_init(&c->dio_write_bioset,
673 4, offsetof(struct dio_write, op.wbio.bio),
674 BIOSET_NEED_BVECS))
675 return -BCH_ERR_ENOMEM_dio_write_bioset_init;
676
677 return 0;
678}
679
680#endif /* NO_BCACHEFS_FS */