projects/linux·blob assoc-array-fixes · refs

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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2001 Andrea Arcangeli <[email protected]> SuSE
5 * Copyright (C) 2016 - 2020 Christoph Hellwig
6 */
7#include <linux/init.h>
8#include <linux/mm.h>
9#include <linux/blkdev.h>
10#include <linux/blk-integrity.h>
11#include <linux/buffer_head.h>
12#include <linux/mpage.h>
13#include <linux/uio.h>
14#include <linux/namei.h>
15#include <linux/task_io_accounting_ops.h>
16#include <linux/falloc.h>
17#include <linux/suspend.h>
18#include <linux/fs.h>
19#include <linux/iomap.h>
20#include <linux/module.h>
21#include <linux/io_uring/cmd.h>
22#include "blk.h"
23
24static inline struct inode *bdev_file_inode(struct file *file)
25{
26 return file->f_mapping->host;
27}
28
29static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
30{
31 blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
32
33 /* avoid the need for a I/O completion work item */
34 if (iocb_is_dsync(iocb))
35 opf |= REQ_FUA;
36 return opf;
37}
38
39static bool blkdev_dio_invalid(struct block_device *bdev, struct kiocb *iocb,
40 struct iov_iter *iter)
41{
42 return (iocb->ki_pos | iov_iter_count(iter)) &
43 (bdev_logical_block_size(bdev) - 1);
44}
45
46static inline int blkdev_iov_iter_get_pages(struct bio *bio,
47 struct iov_iter *iter, struct block_device *bdev)
48{
49 return bio_iov_iter_get_pages(bio, iter, bdev_dma_alignment(bdev),
50 bdev_logical_block_size(bdev) - 1);
51}
52
53#define DIO_INLINE_BIO_VECS 4
54
55static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
56 struct iov_iter *iter, struct block_device *bdev,
57 unsigned int nr_pages)
58{
59 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
60 loff_t pos = iocb->ki_pos;
61 bool should_dirty = false;
62 struct bio bio;
63 ssize_t ret;
64
65 if (nr_pages <= DIO_INLINE_BIO_VECS)
66 vecs = inline_vecs;
67 else {
68 vecs = kmalloc_objs(struct bio_vec, nr_pages);
69 if (!vecs)
70 return -ENOMEM;
71 }
72
73 if (iov_iter_rw(iter) == READ) {
74 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
75 if (user_backed_iter(iter))
76 should_dirty = true;
77 } else {
78 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
79 }
80 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
81 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
82 bio.bi_write_stream = iocb->ki_write_stream;
83 bio.bi_ioprio = iocb->ki_ioprio;
84 if (iocb->ki_flags & IOCB_ATOMIC)
85 bio.bi_opf |= REQ_ATOMIC;
86
87 ret = blkdev_iov_iter_get_pages(&bio, iter, bdev);
88 if (unlikely(ret))
89 goto out;
90 ret = bio.bi_iter.bi_size;
91
92 if (iov_iter_rw(iter) == WRITE)
93 task_io_account_write(ret);
94
95 if (iocb->ki_flags & IOCB_NOWAIT)
96 bio.bi_opf |= REQ_NOWAIT;
97
98 submit_bio_wait(&bio);
99
100 bio_release_pages(&bio, should_dirty);
101 if (unlikely(bio.bi_status))
102 ret = blk_status_to_errno(bio.bi_status);
103
104out:
105 if (vecs != inline_vecs)
106 kfree(vecs);
107
108 bio_uninit(&bio);
109
110 return ret;
111}
112
113enum {
114 DIO_SHOULD_DIRTY = 1,
115 DIO_IS_SYNC = 2,
116};
117
118struct blkdev_dio {
119 union {
120 struct kiocb *iocb;
121 struct task_struct *waiter;
122 };
123 size_t size;
124 atomic_t ref;
125 unsigned int flags;
126 struct bio bio ____cacheline_aligned_in_smp;
127};
128
129static struct bio_set blkdev_dio_pool;
130
131static void blkdev_bio_end_io(struct bio *bio)
132{
133 struct blkdev_dio *dio = bio->bi_private;
134 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
135 bool is_sync = dio->flags & DIO_IS_SYNC;
136
137 if (bio->bi_status && !dio->bio.bi_status)
138 dio->bio.bi_status = bio->bi_status;
139
140 if (bio_integrity(bio))
141 bio_integrity_unmap_user(bio);
142
143 if (atomic_dec_and_test(&dio->ref)) {
144 if (!is_sync) {
145 struct kiocb *iocb = dio->iocb;
146 ssize_t ret;
147
148 WRITE_ONCE(iocb->private, NULL);
149
150 if (likely(!dio->bio.bi_status)) {
151 ret = dio->size;
152 iocb->ki_pos += ret;
153 } else {
154 ret = blk_status_to_errno(dio->bio.bi_status);
155 }
156
157 dio->iocb->ki_complete(iocb, ret);
158 bio_put(&dio->bio);
159 } else {
160 struct task_struct *waiter = dio->waiter;
161
162 WRITE_ONCE(dio->waiter, NULL);
163 blk_wake_io_task(waiter);
164 }
165 }
166
167 if (should_dirty) {
168 bio_check_pages_dirty(bio);
169 } else {
170 bio_release_pages(bio, false);
171 bio_put(bio);
172 }
173}
174
175static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
176 struct block_device *bdev, unsigned int nr_pages)
177{
178 struct blk_plug plug;
179 struct blkdev_dio *dio;
180 struct bio *bio;
181 bool is_read = (iov_iter_rw(iter) == READ), is_sync;
182 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
183 loff_t pos = iocb->ki_pos;
184 int ret = 0;
185
186 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
187 &blkdev_dio_pool);
188 dio = container_of(bio, struct blkdev_dio, bio);
189 atomic_set(&dio->ref, 1);
190 /*
191 * Grab an extra reference to ensure the dio structure which is embedded
192 * into the first bio stays around.
193 */
194 bio_get(bio);
195
196 is_sync = is_sync_kiocb(iocb);
197 if (is_sync) {
198 dio->flags = DIO_IS_SYNC;
199 dio->waiter = current;
200 } else {
201 dio->flags = 0;
202 dio->iocb = iocb;
203 }
204
205 dio->size = 0;
206 if (is_read && user_backed_iter(iter))
207 dio->flags |= DIO_SHOULD_DIRTY;
208
209 blk_start_plug(&plug);
210
211 for (;;) {
212 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
213 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
214 bio->bi_write_stream = iocb->ki_write_stream;
215 bio->bi_private = dio;
216 bio->bi_end_io = blkdev_bio_end_io;
217 bio->bi_ioprio = iocb->ki_ioprio;
218
219 ret = blkdev_iov_iter_get_pages(bio, iter, bdev);
220 if (unlikely(ret)) {
221 bio_endio_status(bio, errno_to_blk_status(ret));
222 break;
223 }
224 if (iocb->ki_flags & IOCB_NOWAIT) {
225 /*
226 * This is nonblocking IO, and we need to allocate
227 * another bio if we have data left to map. As we
228 * cannot guarantee that one of the sub bios will not
229 * fail getting issued FOR NOWAIT and as error results
230 * are coalesced across all of them, be safe and ask for
231 * a retry of this from blocking context.
232 */
233 if (unlikely(iov_iter_count(iter))) {
234 ret = -EAGAIN;
235 goto fail;
236 }
237 bio->bi_opf |= REQ_NOWAIT;
238 }
239 if (iocb->ki_flags & IOCB_HAS_METADATA) {
240 ret = bio_integrity_map_iter(bio, iocb->private);
241 if (unlikely(ret)) {
242 bio_endio_status(bio, errno_to_blk_status(ret));
243 break;
244 }
245 }
246
247 if (is_read) {
248 if (dio->flags & DIO_SHOULD_DIRTY)
249 bio_set_pages_dirty(bio);
250 } else {
251 task_io_account_write(bio->bi_iter.bi_size);
252 }
253 dio->size += bio->bi_iter.bi_size;
254 pos += bio->bi_iter.bi_size;
255
256 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
257 if (!nr_pages) {
258 submit_bio(bio);
259 break;
260 }
261 atomic_inc(&dio->ref);
262 submit_bio(bio);
263 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
264 }
265
266 blk_finish_plug(&plug);
267
268 if (!is_sync)
269 return -EIOCBQUEUED;
270
271 for (;;) {
272 set_current_state(TASK_UNINTERRUPTIBLE);
273 if (!READ_ONCE(dio->waiter))
274 break;
275 blk_io_schedule();
276 }
277 __set_current_state(TASK_RUNNING);
278
279 if (!ret)
280 ret = blk_status_to_errno(dio->bio.bi_status);
281 if (likely(!ret))
282 ret = dio->size;
283
284 bio_put(&dio->bio);
285 return ret;
286fail:
287 bio_release_pages(bio, false);
288 bio_clear_flag(bio, BIO_REFFED);
289 bio_put(bio);
290 blk_finish_plug(&plug);
291 return ret;
292}
293
294static void blkdev_bio_end_io_async(struct bio *bio)
295{
296 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
297 struct kiocb *iocb = dio->iocb;
298 ssize_t ret;
299
300 WRITE_ONCE(iocb->private, NULL);
301
302 if (likely(!bio->bi_status)) {
303 ret = dio->size;
304 iocb->ki_pos += ret;
305 } else {
306 ret = blk_status_to_errno(bio->bi_status);
307 }
308
309 if (bio_integrity(bio))
310 bio_integrity_unmap_user(bio);
311
312 iocb->ki_complete(iocb, ret);
313
314 if (dio->flags & DIO_SHOULD_DIRTY) {
315 bio_check_pages_dirty(bio);
316 } else {
317 bio_release_pages(bio, false);
318 bio_put(bio);
319 }
320}
321
322static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
323 struct iov_iter *iter,
324 struct block_device *bdev,
325 unsigned int nr_pages)
326{
327 bool is_read = iov_iter_rw(iter) == READ;
328 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
329 struct blkdev_dio *dio;
330 struct bio *bio;
331 loff_t pos = iocb->ki_pos;
332 int ret = 0;
333
334 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
335 &blkdev_dio_pool);
336 dio = container_of(bio, struct blkdev_dio, bio);
337 dio->flags = 0;
338 dio->iocb = iocb;
339 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
340 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
341 bio->bi_write_stream = iocb->ki_write_stream;
342 bio->bi_end_io = blkdev_bio_end_io_async;
343 bio->bi_ioprio = iocb->ki_ioprio;
344
345 /*
346 * Users don't rely on the iterator being in any particular
347 * state for async I/O returning -EIOCBQUEUED, hence we can
348 * avoid expensive iov_iter_advance(). Bypass
349 * bio_iov_iter_get_pages() and set the bvec directly.
350 */
351 if (!bio_iov_iter_set(bio, iter)) {
352 ret = blkdev_iov_iter_get_pages(bio, iter, bdev);
353 if (unlikely(ret))
354 goto out_bio_put;
355 }
356 dio->size = bio->bi_iter.bi_size;
357
358 if (is_read) {
359 if (user_backed_iter(iter)) {
360 dio->flags |= DIO_SHOULD_DIRTY;
361 bio_set_pages_dirty(bio);
362 }
363 } else {
364 task_io_account_write(bio->bi_iter.bi_size);
365 }
366
367 if (iocb->ki_flags & IOCB_HAS_METADATA) {
368 ret = bio_integrity_map_iter(bio, iocb->private);
369 WRITE_ONCE(iocb->private, NULL);
370 if (unlikely(ret))
371 goto out_bio_put;
372 }
373
374 if (iocb->ki_flags & IOCB_ATOMIC)
375 bio->bi_opf |= REQ_ATOMIC;
376
377 if (iocb->ki_flags & IOCB_NOWAIT)
378 bio->bi_opf |= REQ_NOWAIT;
379
380 if (iocb->ki_flags & IOCB_HIPRI) {
381 bio->bi_opf |= REQ_POLLED;
382 submit_bio(bio);
383 WRITE_ONCE(iocb->private, bio);
384 } else {
385 submit_bio(bio);
386 }
387 return -EIOCBQUEUED;
388
389out_bio_put:
390 bio_put(bio);
391 return ret;
392}
393
394static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
395{
396 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
397 unsigned int nr_pages;
398
399 if (!iov_iter_count(iter))
400 return 0;
401
402 if (blkdev_dio_invalid(bdev, iocb, iter))
403 return -EINVAL;
404
405 /* HIPRI needs private as bio; HAS_METADATA keeps it as uio_meta */
406 if ((iocb->ki_flags & IOCB_HIPRI) &&
407 (iocb->ki_flags & IOCB_HAS_METADATA))
408 return -EOPNOTSUPP;
409
410 if (iov_iter_rw(iter) == WRITE) {
411 u16 max_write_streams = bdev_max_write_streams(bdev);
412
413 if (iocb->ki_write_stream) {
414 if (iocb->ki_write_stream > max_write_streams)
415 return -EINVAL;
416 } else if (max_write_streams) {
417 enum rw_hint write_hint =
418 file_inode(iocb->ki_filp)->i_write_hint;
419
420 /*
421 * Just use the write hint as write stream for block
422 * device writes. This assumes no file system is
423 * mounted that would use the streams differently.
424 */
425 if (write_hint <= max_write_streams)
426 iocb->ki_write_stream = write_hint;
427 }
428 }
429
430 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
431 if (likely(nr_pages <= BIO_MAX_VECS &&
432 !(iocb->ki_flags & IOCB_HAS_METADATA))) {
433 if (is_sync_kiocb(iocb))
434 return __blkdev_direct_IO_simple(iocb, iter, bdev,
435 nr_pages);
436 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);
437 } else if (iocb->ki_flags & IOCB_ATOMIC) {
438 return -EINVAL;
439 }
440 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));
441}
442
443static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
444 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
445{
446 struct block_device *bdev = I_BDEV(inode);
447 loff_t isize = i_size_read(inode);
448
449 if (offset >= isize)
450 return -EIO;
451
452 iomap->bdev = bdev;
453 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
454 iomap->type = IOMAP_MAPPED;
455 iomap->addr = iomap->offset;
456 iomap->length = isize - iomap->offset;
457 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
458 return 0;
459}
460
461static DEFINE_IOMAP_ITER_NEXT(blkdev_iomap_next, blkdev_iomap_begin);
462
463static const struct iomap_ops blkdev_iomap_ops = {
464 .iomap_next = blkdev_iomap_next,
465};
466
467#ifdef CONFIG_BUFFER_HEAD
468static int blkdev_get_block(struct inode *inode, sector_t iblock,
469 struct buffer_head *bh, int create)
470{
471 bh->b_bdev = I_BDEV(inode);
472 bh->b_blocknr = iblock;
473 set_buffer_mapped(bh);
474 return 0;
475}
476
477/*
478 * We cannot call mpage_writepages() as it does not take the buffer lock.
479 * We must use block_write_full_folio() directly which holds the buffer
480 * lock. The buffer lock provides the synchronisation with writeback
481 * that filesystems rely on when they use the blockdev's mapping.
482 */
483static int blkdev_writepages(struct address_space *mapping,
484 struct writeback_control *wbc)
485{
486 struct folio *folio = NULL;
487 struct blk_plug plug;
488 int err;
489
490 blk_start_plug(&plug);
491 while ((folio = writeback_iter(mapping, wbc, folio, &err)))
492 err = block_write_full_folio(folio, wbc, blkdev_get_block);
493 blk_finish_plug(&plug);
494
495 return err;
496}
497
498static int blkdev_read_folio(struct file *file, struct folio *folio)
499{
500 return block_read_full_folio(folio, blkdev_get_block);
501}
502
503static void blkdev_readahead(struct readahead_control *rac)
504{
505 mpage_readahead(rac, blkdev_get_block);
506}
507
508const struct address_space_operations def_blk_aops = {
509 .dirty_folio = block_dirty_folio,
510 .invalidate_folio = block_invalidate_folio,
511 .read_folio = blkdev_read_folio,
512 .readahead = blkdev_readahead,
513 .writepages = blkdev_writepages,
514 .migrate_folio = buffer_migrate_folio_norefs,
515 .is_dirty_writeback = buffer_check_dirty_writeback,
516};
517#else /* CONFIG_BUFFER_HEAD */
518static int blkdev_read_folio(struct file *file, struct folio *folio)
519{
520 iomap_bio_read_folio(folio, &blkdev_iomap_ops);
521 return 0;
522}
523
524static void blkdev_readahead(struct readahead_control *rac)
525{
526 iomap_bio_readahead(rac, &blkdev_iomap_ops);
527}
528
529static ssize_t blkdev_writeback_range(struct iomap_writepage_ctx *wpc,
530 struct folio *folio, u64 offset, unsigned int len, u64 end_pos)
531{
532 loff_t isize = i_size_read(wpc->inode);
533
534 if (WARN_ON_ONCE(offset >= isize))
535 return -EIO;
536
537 if (offset < wpc->iomap.offset ||
538 offset >= wpc->iomap.offset + wpc->iomap.length) {
539 int error;
540
541 error = blkdev_iomap_begin(wpc->inode, offset, isize - offset,
542 IOMAP_WRITE, &wpc->iomap, NULL);
543 if (error)
544 return error;
545 }
546
547 return iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
548}
549
550static const struct iomap_writeback_ops blkdev_writeback_ops = {
551 .writeback_range = blkdev_writeback_range,
552 .writeback_submit = iomap_ioend_writeback_submit,
553};
554
555static int blkdev_writepages(struct address_space *mapping,
556 struct writeback_control *wbc)
557{
558 struct iomap_writepage_ctx wpc = {
559 .inode = mapping->host,
560 .wbc = wbc,
561 .ops = &blkdev_writeback_ops
562 };
563
564 return iomap_writepages(&wpc);
565}
566
567const struct address_space_operations def_blk_aops = {
568 .dirty_folio = filemap_dirty_folio,
569 .release_folio = iomap_release_folio,
570 .invalidate_folio = iomap_invalidate_folio,
571 .read_folio = blkdev_read_folio,
572 .readahead = blkdev_readahead,
573 .writepages = blkdev_writepages,
574 .is_partially_uptodate = iomap_is_partially_uptodate,
575 .error_remove_folio = generic_error_remove_folio,
576 .migrate_folio = filemap_migrate_folio,
577};
578#endif /* CONFIG_BUFFER_HEAD */
579
580/*
581 * for a block special file file_inode(file)->i_size is zero
582 * so we compute the size by hand (just as in block_read/write above)
583 */
584static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
585{
586 struct inode *bd_inode = bdev_file_inode(file);
587 loff_t retval;
588
589 inode_lock(bd_inode);
590 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
591 inode_unlock(bd_inode);
592 return retval;
593}
594
595static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
596 int datasync)
597{
598 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
599 int error;
600
601 error = file_write_and_wait_range(filp, start, end);
602 if (error)
603 return error;
604
605 /*
606 * There is no need to serialise calls to blkdev_issue_flush with
607 * i_mutex and doing so causes performance issues with concurrent
608 * O_SYNC writers to a block device.
609 */
610 error = blkdev_issue_flush(bdev);
611 if (error == -EOPNOTSUPP)
612 error = 0;
613
614 return error;
615}
616
617/**
618 * file_to_blk_mode - get block open flags from file flags
619 * @file: file whose open flags should be converted
620 *
621 * Look at file open flags and generate corresponding block open flags from
622 * them. The function works both for file just being open (e.g. during ->open
623 * callback) and for file that is already open. This is actually non-trivial
624 * (see comment in the function).
625 */
626blk_mode_t file_to_blk_mode(struct file *file)
627{
628 blk_mode_t mode = 0;
629
630 if (file->f_mode & FMODE_READ)
631 mode |= BLK_OPEN_READ;
632 if (file->f_mode & FMODE_WRITE)
633 mode |= BLK_OPEN_WRITE;
634 /*
635 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data
636 * to determine whether the open was exclusive for already open files.
637 */
638 if (file->private_data)
639 mode |= BLK_OPEN_EXCL;
640 else if (file->f_flags & O_EXCL)
641 mode |= BLK_OPEN_EXCL;
642 if (file->f_flags & O_NDELAY)
643 mode |= BLK_OPEN_NDELAY;
644
645 /*
646 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
647 * driver has historically allowed ioctls as if the file was opened for
648 * writing, but does not allow and actual reads or writes.
649 */
650 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
651 mode |= BLK_OPEN_WRITE_IOCTL;
652
653 return mode;
654}
655
656static int blkdev_open(struct inode *inode, struct file *filp)
657{
658 struct block_device *bdev;
659 blk_mode_t mode;
660 int ret;
661
662 mode = file_to_blk_mode(filp);
663 /* Use the file as the holder. */
664 if (mode & BLK_OPEN_EXCL)
665 filp->private_data = filp;
666 ret = bdev_permission(inode->i_rdev, mode, filp->private_data);
667 if (ret)
668 return ret;
669
670 bdev = blkdev_get_no_open(inode->i_rdev, true);
671 if (!bdev)
672 return -ENXIO;
673
674 if (bdev_can_atomic_write(bdev))
675 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;
676 if (blk_get_integrity(bdev->bd_disk))
677 filp->f_mode |= FMODE_HAS_METADATA;
678
679 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp);
680 if (ret)
681 blkdev_put_no_open(bdev);
682 return ret;
683}
684
685static int blkdev_release(struct inode *inode, struct file *filp)
686{
687 bdev_release(filp);
688 return 0;
689}
690
691static ssize_t
692blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
693{
694 size_t count = iov_iter_count(from);
695 ssize_t written;
696
697 written = kiocb_invalidate_pages(iocb, count);
698 if (written) {
699 if (written == -EBUSY)
700 return 0;
701 return written;
702 }
703
704 written = blkdev_direct_IO(iocb, from);
705 if (written > 0) {
706 kiocb_invalidate_post_direct_write(iocb, count);
707 iocb->ki_pos += written;
708 count -= written;
709 }
710 if (written != -EIOCBQUEUED)
711 iov_iter_revert(from, count - iov_iter_count(from));
712 return written;
713}
714
715static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
716{
717 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL,
718 NULL);
719}
720
721/*
722 * Write data to the block device. Only intended for the block device itself
723 * and the raw driver which basically is a fake block device.
724 *
725 * Does not take i_mutex for the write and thus is not for general purpose
726 * use.
727 */
728static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
729{
730 struct file *file = iocb->ki_filp;
731 struct inode *bd_inode = bdev_file_inode(file);
732 struct block_device *bdev = I_BDEV(bd_inode);
733 bool atomic = iocb->ki_flags & IOCB_ATOMIC;
734 loff_t size = bdev_nr_bytes(bdev);
735 size_t shorted = 0;
736 ssize_t ret;
737
738 if (bdev_read_only(bdev))
739 return -EPERM;
740
741 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
742 return -ETXTBSY;
743
744 if (!iov_iter_count(from))
745 return 0;
746
747 if (iocb->ki_pos >= size)
748 return -ENOSPC;
749
750 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
751 return -EOPNOTSUPP;
752
753 if (atomic) {
754 ret = generic_atomic_write_valid(iocb, from);
755 if (ret)
756 return ret;
757 }
758
759 size -= iocb->ki_pos;
760 if (iov_iter_count(from) > size) {
761 if (atomic)
762 return -EINVAL;
763 shorted = iov_iter_count(from) - size;
764 iov_iter_truncate(from, size);
765 }
766
767 ret = file_update_time(file);
768 if (ret)
769 return ret;
770
771 if (iocb->ki_flags & IOCB_DIRECT) {
772 ret = blkdev_direct_write(iocb, from);
773 if (ret >= 0 && iov_iter_count(from))
774 ret = direct_write_fallback(iocb, from, ret,
775 blkdev_buffered_write(iocb, from));
776 } else {
777 /*
778 * Take i_rwsem and invalidate_lock to avoid racing with
779 * set_blocksize changing i_blkbits/folio order and punching
780 * out the pagecache.
781 */
782 inode_lock_shared(bd_inode);
783 ret = blkdev_buffered_write(iocb, from);
784 inode_unlock_shared(bd_inode);
785 }
786
787 if (ret > 0)
788 ret = generic_write_sync(iocb, ret);
789 iov_iter_reexpand(from, iov_iter_count(from) + shorted);
790 return ret;
791}
792
793static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
794{
795 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp);
796 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
797 loff_t size = bdev_nr_bytes(bdev);
798 loff_t pos = iocb->ki_pos;
799 size_t shorted = 0;
800 ssize_t ret = 0;
801 size_t count;
802
803 if (unlikely(pos + iov_iter_count(to) > size)) {
804 if (pos >= size)
805 return 0;
806 size -= pos;
807 shorted = iov_iter_count(to) - size;
808 iov_iter_truncate(to, size);
809 }
810
811 count = iov_iter_count(to);
812 if (!count)
813 goto reexpand; /* skip atime */
814
815 if (iocb->ki_flags & IOCB_DIRECT) {
816 ret = kiocb_write_and_wait(iocb, count);
817 if (ret < 0)
818 goto reexpand;
819 file_accessed(iocb->ki_filp);
820
821 ret = blkdev_direct_IO(iocb, to);
822 if (ret > 0) {
823 iocb->ki_pos += ret;
824 count -= ret;
825 }
826 if (ret != -EIOCBQUEUED)
827 iov_iter_revert(to, count - iov_iter_count(to));
828 if (ret < 0 || !count)
829 goto reexpand;
830 }
831
832 /*
833 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize
834 * changing i_blkbits/folio order and punching out the pagecache.
835 */
836 inode_lock_shared(bd_inode);
837 ret = filemap_read(iocb, to, ret);
838 inode_unlock_shared(bd_inode);
839
840reexpand:
841 if (unlikely(shorted))
842 iov_iter_reexpand(to, iov_iter_count(to) + shorted);
843 return ret;
844}
845
846#define BLKDEV_FALLOC_FL_SUPPORTED \
847 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
848 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES)
849
850static long blkdev_fallocate(struct file *file, int mode, loff_t start,
851 loff_t len)
852{
853 struct inode *inode = bdev_file_inode(file);
854 struct block_device *bdev = I_BDEV(inode);
855 loff_t end = start + len - 1;
856 loff_t isize;
857 unsigned int flags;
858 int error;
859
860 /* Fail if we don't recognize the flags. */
861 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
862 return -EOPNOTSUPP;
863 /*
864 * Don't allow writing zeroes if the device does not enable the
865 * unmap write zeroes operation.
866 */
867 if ((mode & FALLOC_FL_WRITE_ZEROES) &&
868 !bdev_write_zeroes_unmap_sectors(bdev))
869 return -EOPNOTSUPP;
870
871 /* Don't go off the end of the device. */
872 isize = bdev_nr_bytes(bdev);
873 if (start >= isize)
874 return -EINVAL;
875 if (end >= isize) {
876 if (mode & FALLOC_FL_KEEP_SIZE) {
877 len = isize - start;
878 end = start + len - 1;
879 } else
880 return -EINVAL;
881 }
882
883 /*
884 * Don't allow IO that isn't aligned to logical block size.
885 */
886 if ((start | len) & (bdev_logical_block_size(bdev) - 1))
887 return -EINVAL;
888
889 inode_lock(inode);
890 filemap_invalidate_lock(inode->i_mapping);
891
892 switch (mode) {
893 case FALLOC_FL_ZERO_RANGE:
894 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
895 flags = BLKDEV_ZERO_NOUNMAP;
896 break;
897 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
898 flags = BLKDEV_ZERO_NOFALLBACK;
899 break;
900 case FALLOC_FL_WRITE_ZEROES:
901 flags = 0;
902 break;
903 default:
904 error = -EOPNOTSUPP;
905 goto fail;
906 }
907
908 /*
909 * Invalidate the page cache, including dirty pages, for valid
910 * de-allocate mode calls to fallocate().
911 */
912 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
913 if (error)
914 goto fail;
915
916 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
917 len >> SECTOR_SHIFT, GFP_KERNEL, flags);
918 fail:
919 filemap_invalidate_unlock(inode->i_mapping);
920 inode_unlock(inode);
921 return error;
922}
923
924static int blkdev_mmap_prepare(struct vm_area_desc *desc)
925{
926 struct file *file = desc->file;
927
928 if (bdev_read_only(I_BDEV(bdev_file_inode(file))))
929 return generic_file_readonly_mmap_prepare(desc);
930
931 return generic_file_mmap_prepare(desc);
932}
933
934const struct file_operations def_blk_fops = {
935 .open = blkdev_open,
936 .release = blkdev_release,
937 .llseek = blkdev_llseek,
938 .read_iter = blkdev_read_iter,
939 .write_iter = blkdev_write_iter,
940 .iopoll = iocb_bio_iopoll,
941 .mmap_prepare = blkdev_mmap_prepare,
942 .fsync = blkdev_fsync,
943 .unlocked_ioctl = blkdev_ioctl,
944#ifdef CONFIG_COMPAT
945 .compat_ioctl = compat_blkdev_ioctl,
946#endif
947 .splice_read = filemap_splice_read,
948 .splice_write = iter_file_splice_write,
949 .fallocate = blkdev_fallocate,
950 .uring_cmd = blkdev_uring_cmd,
951 .fop_flags = FOP_BUFFER_RASYNC | FOP_DONTCACHE,
952};
953
954static __init int blkdev_init(void)
955{
956 return bioset_init(&blkdev_dio_pool, 4,
957 offsetof(struct blkdev_dio, bio),
958 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
959}
960module_init(blkdev_init);