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