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/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
bdev_file_inode(struct file * file)24 static inline struct inode *bdev_file_inode(struct file *file)
25 {
26 return file->f_mapping->host;
27 }
28
dio_bio_write_op(struct kiocb * iocb)29 static 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
blkdev_dio_invalid(struct block_device * bdev,struct kiocb * iocb,struct iov_iter * iter)39 static 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
blkdev_iov_iter_get_pages(struct bio * bio,struct iov_iter * iter,struct block_device * bdev)46 static 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
__blkdev_direct_IO_simple(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)55 static 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
104 out:
105 if (vecs != inline_vecs)
106 kfree(vecs);
107
108 bio_uninit(&bio);
109
110 return ret;
111 }
112
113 enum {
114 DIO_SHOULD_DIRTY = 1,
115 DIO_IS_SYNC = 2,
116 };
117
118 struct 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
129 static struct bio_set blkdev_dio_pool;
130
blkdev_bio_end_io(struct bio * bio)131 static 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
__blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)175 static 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;
286 fail:
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
blkdev_bio_end_io_async(struct bio * bio)294 static 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
__blkdev_direct_IO_async(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)322 static 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
389 out_bio_put:
390 bio_put(bio);
391 return ret;
392 }
393
blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter)394 static 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 if (iov_iter_rw(iter) == WRITE) {
406 u16 max_write_streams = bdev_max_write_streams(bdev);
407
408 if (iocb->ki_write_stream) {
409 if (iocb->ki_write_stream > max_write_streams)
410 return -EINVAL;
411 } else if (max_write_streams) {
412 enum rw_hint write_hint =
413 file_inode(iocb->ki_filp)->i_write_hint;
414
415 /*
416 * Just use the write hint as write stream for block
417 * device writes. This assumes no file system is
418 * mounted that would use the streams differently.
419 */
420 if (write_hint <= max_write_streams)
421 iocb->ki_write_stream = write_hint;
422 }
423 }
424
425 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
426 if (likely(nr_pages <= BIO_MAX_VECS &&
427 !(iocb->ki_flags & IOCB_HAS_METADATA))) {
428 if (is_sync_kiocb(iocb))
429 return __blkdev_direct_IO_simple(iocb, iter, bdev,
430 nr_pages);
431 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);
432 } else if (iocb->ki_flags & IOCB_ATOMIC) {
433 return -EINVAL;
434 }
435 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));
436 }
437
blkdev_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned int flags,struct iomap * iomap,struct iomap * srcmap)438 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
439 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
440 {
441 struct block_device *bdev = I_BDEV(inode);
442 loff_t isize = i_size_read(inode);
443
444 if (offset >= isize)
445 return -EIO;
446
447 iomap->bdev = bdev;
448 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
449 iomap->type = IOMAP_MAPPED;
450 iomap->addr = iomap->offset;
451 iomap->length = isize - iomap->offset;
452 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
453 return 0;
454 }
455
456 static DEFINE_IOMAP_ITER_NEXT(blkdev_iomap_next, blkdev_iomap_begin);
457
458 static const struct iomap_ops blkdev_iomap_ops = {
459 .iomap_next = blkdev_iomap_next,
460 };
461
462 #ifdef CONFIG_BUFFER_HEAD
blkdev_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)463 static int blkdev_get_block(struct inode *inode, sector_t iblock,
464 struct buffer_head *bh, int create)
465 {
466 bh->b_bdev = I_BDEV(inode);
467 bh->b_blocknr = iblock;
468 set_buffer_mapped(bh);
469 return 0;
470 }
471
472 /*
473 * We cannot call mpage_writepages() as it does not take the buffer lock.
474 * We must use block_write_full_folio() directly which holds the buffer
475 * lock. The buffer lock provides the synchronisation with writeback
476 * that filesystems rely on when they use the blockdev's mapping.
477 */
blkdev_writepages(struct address_space * mapping,struct writeback_control * wbc)478 static int blkdev_writepages(struct address_space *mapping,
479 struct writeback_control *wbc)
480 {
481 struct folio *folio = NULL;
482 struct blk_plug plug;
483 int err;
484
485 blk_start_plug(&plug);
486 while ((folio = writeback_iter(mapping, wbc, folio, &err)))
487 err = block_write_full_folio(folio, wbc, blkdev_get_block);
488 blk_finish_plug(&plug);
489
490 return err;
491 }
492
blkdev_read_folio(struct file * file,struct folio * folio)493 static int blkdev_read_folio(struct file *file, struct folio *folio)
494 {
495 return block_read_full_folio(folio, blkdev_get_block);
496 }
497
blkdev_readahead(struct readahead_control * rac)498 static void blkdev_readahead(struct readahead_control *rac)
499 {
500 mpage_readahead(rac, blkdev_get_block);
501 }
502
503 const struct address_space_operations def_blk_aops = {
504 .dirty_folio = block_dirty_folio,
505 .invalidate_folio = block_invalidate_folio,
506 .read_folio = blkdev_read_folio,
507 .readahead = blkdev_readahead,
508 .writepages = blkdev_writepages,
509 .migrate_folio = buffer_migrate_folio_norefs,
510 .is_dirty_writeback = buffer_check_dirty_writeback,
511 };
512 #else /* CONFIG_BUFFER_HEAD */
blkdev_read_folio(struct file * file,struct folio * folio)513 static int blkdev_read_folio(struct file *file, struct folio *folio)
514 {
515 iomap_bio_read_folio(folio, &blkdev_iomap_ops);
516 return 0;
517 }
518
blkdev_readahead(struct readahead_control * rac)519 static void blkdev_readahead(struct readahead_control *rac)
520 {
521 iomap_bio_readahead(rac, &blkdev_iomap_ops);
522 }
523
blkdev_writeback_range(struct iomap_writepage_ctx * wpc,struct folio * folio,u64 offset,unsigned int len,u64 end_pos)524 static ssize_t blkdev_writeback_range(struct iomap_writepage_ctx *wpc,
525 struct folio *folio, u64 offset, unsigned int len, u64 end_pos)
526 {
527 loff_t isize = i_size_read(wpc->inode);
528
529 if (WARN_ON_ONCE(offset >= isize))
530 return -EIO;
531
532 if (offset < wpc->iomap.offset ||
533 offset >= wpc->iomap.offset + wpc->iomap.length) {
534 int error;
535
536 error = blkdev_iomap_begin(wpc->inode, offset, isize - offset,
537 IOMAP_WRITE, &wpc->iomap, NULL);
538 if (error)
539 return error;
540 }
541
542 return iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
543 }
544
545 static const struct iomap_writeback_ops blkdev_writeback_ops = {
546 .writeback_range = blkdev_writeback_range,
547 .writeback_submit = iomap_ioend_writeback_submit,
548 };
549
blkdev_writepages(struct address_space * mapping,struct writeback_control * wbc)550 static int blkdev_writepages(struct address_space *mapping,
551 struct writeback_control *wbc)
552 {
553 struct iomap_writepage_ctx wpc = {
554 .inode = mapping->host,
555 .wbc = wbc,
556 .ops = &blkdev_writeback_ops
557 };
558
559 return iomap_writepages(&wpc);
560 }
561
562 const struct address_space_operations def_blk_aops = {
563 .dirty_folio = filemap_dirty_folio,
564 .release_folio = iomap_release_folio,
565 .invalidate_folio = iomap_invalidate_folio,
566 .read_folio = blkdev_read_folio,
567 .readahead = blkdev_readahead,
568 .writepages = blkdev_writepages,
569 .is_partially_uptodate = iomap_is_partially_uptodate,
570 .error_remove_folio = generic_error_remove_folio,
571 .migrate_folio = filemap_migrate_folio,
572 };
573 #endif /* CONFIG_BUFFER_HEAD */
574
575 /*
576 * for a block special file file_inode(file)->i_size is zero
577 * so we compute the size by hand (just as in block_read/write above)
578 */
blkdev_llseek(struct file * file,loff_t offset,int whence)579 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
580 {
581 struct inode *bd_inode = bdev_file_inode(file);
582 loff_t retval;
583
584 inode_lock(bd_inode);
585 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
586 inode_unlock(bd_inode);
587 return retval;
588 }
589
blkdev_fsync(struct file * filp,loff_t start,loff_t end,int datasync)590 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
591 int datasync)
592 {
593 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
594 int error;
595
596 error = file_write_and_wait_range(filp, start, end);
597 if (error)
598 return error;
599
600 /*
601 * There is no need to serialise calls to blkdev_issue_flush with
602 * i_mutex and doing so causes performance issues with concurrent
603 * O_SYNC writers to a block device.
604 */
605 error = blkdev_issue_flush(bdev);
606 if (error == -EOPNOTSUPP)
607 error = 0;
608
609 return error;
610 }
611
612 /**
613 * file_to_blk_mode - get block open flags from file flags
614 * @file: file whose open flags should be converted
615 *
616 * Look at file open flags and generate corresponding block open flags from
617 * them. The function works both for file just being open (e.g. during ->open
618 * callback) and for file that is already open. This is actually non-trivial
619 * (see comment in the function).
620 */
file_to_blk_mode(struct file * file)621 blk_mode_t file_to_blk_mode(struct file *file)
622 {
623 blk_mode_t mode = 0;
624
625 if (file->f_mode & FMODE_READ)
626 mode |= BLK_OPEN_READ;
627 if (file->f_mode & FMODE_WRITE)
628 mode |= BLK_OPEN_WRITE;
629 /*
630 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data
631 * to determine whether the open was exclusive for already open files.
632 */
633 if (file->private_data)
634 mode |= BLK_OPEN_EXCL;
635 else if (file->f_flags & O_EXCL)
636 mode |= BLK_OPEN_EXCL;
637 if (file->f_flags & O_NDELAY)
638 mode |= BLK_OPEN_NDELAY;
639
640 /*
641 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
642 * driver has historically allowed ioctls as if the file was opened for
643 * writing, but does not allow and actual reads or writes.
644 */
645 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
646 mode |= BLK_OPEN_WRITE_IOCTL;
647
648 return mode;
649 }
650
blkdev_open(struct inode * inode,struct file * filp)651 static int blkdev_open(struct inode *inode, struct file *filp)
652 {
653 struct block_device *bdev;
654 blk_mode_t mode;
655 int ret;
656
657 mode = file_to_blk_mode(filp);
658 /* Use the file as the holder. */
659 if (mode & BLK_OPEN_EXCL)
660 filp->private_data = filp;
661 ret = bdev_permission(inode->i_rdev, mode, filp->private_data);
662 if (ret)
663 return ret;
664
665 bdev = blkdev_get_no_open(inode->i_rdev, true);
666 if (!bdev)
667 return -ENXIO;
668
669 if (bdev_can_atomic_write(bdev))
670 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;
671 if (blk_get_integrity(bdev->bd_disk))
672 filp->f_mode |= FMODE_HAS_METADATA;
673
674 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp);
675 if (ret)
676 blkdev_put_no_open(bdev);
677 return ret;
678 }
679
blkdev_release(struct inode * inode,struct file * filp)680 static int blkdev_release(struct inode *inode, struct file *filp)
681 {
682 bdev_release(filp);
683 return 0;
684 }
685
686 static ssize_t
blkdev_direct_write(struct kiocb * iocb,struct iov_iter * from)687 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
688 {
689 size_t count = iov_iter_count(from);
690 ssize_t written;
691
692 written = kiocb_invalidate_pages(iocb, count);
693 if (written) {
694 if (written == -EBUSY)
695 return 0;
696 return written;
697 }
698
699 written = blkdev_direct_IO(iocb, from);
700 if (written > 0) {
701 kiocb_invalidate_post_direct_write(iocb, count);
702 iocb->ki_pos += written;
703 count -= written;
704 }
705 if (written != -EIOCBQUEUED)
706 iov_iter_revert(from, count - iov_iter_count(from));
707 return written;
708 }
709
blkdev_buffered_write(struct kiocb * iocb,struct iov_iter * from)710 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
711 {
712 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL,
713 NULL);
714 }
715
716 /*
717 * Write data to the block device. Only intended for the block device itself
718 * and the raw driver which basically is a fake block device.
719 *
720 * Does not take i_mutex for the write and thus is not for general purpose
721 * use.
722 */
blkdev_write_iter(struct kiocb * iocb,struct iov_iter * from)723 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
724 {
725 struct file *file = iocb->ki_filp;
726 struct inode *bd_inode = bdev_file_inode(file);
727 struct block_device *bdev = I_BDEV(bd_inode);
728 bool atomic = iocb->ki_flags & IOCB_ATOMIC;
729 loff_t size = bdev_nr_bytes(bdev);
730 size_t shorted = 0;
731 ssize_t ret;
732
733 if (bdev_read_only(bdev))
734 return -EPERM;
735
736 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
737 return -ETXTBSY;
738
739 if (!iov_iter_count(from))
740 return 0;
741
742 if (iocb->ki_pos >= size)
743 return -ENOSPC;
744
745 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
746 return -EOPNOTSUPP;
747
748 if (atomic) {
749 ret = generic_atomic_write_valid(iocb, from);
750 if (ret)
751 return ret;
752 }
753
754 size -= iocb->ki_pos;
755 if (iov_iter_count(from) > size) {
756 if (atomic)
757 return -EINVAL;
758 shorted = iov_iter_count(from) - size;
759 iov_iter_truncate(from, size);
760 }
761
762 ret = file_update_time(file);
763 if (ret)
764 return ret;
765
766 if (iocb->ki_flags & IOCB_DIRECT) {
767 ret = blkdev_direct_write(iocb, from);
768 if (ret >= 0 && iov_iter_count(from))
769 ret = direct_write_fallback(iocb, from, ret,
770 blkdev_buffered_write(iocb, from));
771 } else {
772 /*
773 * Take i_rwsem and invalidate_lock to avoid racing with
774 * set_blocksize changing i_blkbits/folio order and punching
775 * out the pagecache.
776 */
777 inode_lock_shared(bd_inode);
778 ret = blkdev_buffered_write(iocb, from);
779 inode_unlock_shared(bd_inode);
780 }
781
782 if (ret > 0)
783 ret = generic_write_sync(iocb, ret);
784 iov_iter_reexpand(from, iov_iter_count(from) + shorted);
785 return ret;
786 }
787
blkdev_read_iter(struct kiocb * iocb,struct iov_iter * to)788 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
789 {
790 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp);
791 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
792 loff_t size = bdev_nr_bytes(bdev);
793 loff_t pos = iocb->ki_pos;
794 size_t shorted = 0;
795 ssize_t ret = 0;
796 size_t count;
797
798 if (unlikely(pos + iov_iter_count(to) > size)) {
799 if (pos >= size)
800 return 0;
801 size -= pos;
802 shorted = iov_iter_count(to) - size;
803 iov_iter_truncate(to, size);
804 }
805
806 count = iov_iter_count(to);
807 if (!count)
808 goto reexpand; /* skip atime */
809
810 if (iocb->ki_flags & IOCB_DIRECT) {
811 ret = kiocb_write_and_wait(iocb, count);
812 if (ret < 0)
813 goto reexpand;
814 file_accessed(iocb->ki_filp);
815
816 ret = blkdev_direct_IO(iocb, to);
817 if (ret > 0) {
818 iocb->ki_pos += ret;
819 count -= ret;
820 }
821 if (ret != -EIOCBQUEUED)
822 iov_iter_revert(to, count - iov_iter_count(to));
823 if (ret < 0 || !count)
824 goto reexpand;
825 }
826
827 /*
828 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize
829 * changing i_blkbits/folio order and punching out the pagecache.
830 */
831 inode_lock_shared(bd_inode);
832 ret = filemap_read(iocb, to, ret);
833 inode_unlock_shared(bd_inode);
834
835 reexpand:
836 if (unlikely(shorted))
837 iov_iter_reexpand(to, iov_iter_count(to) + shorted);
838 return ret;
839 }
840
841 #define BLKDEV_FALLOC_FL_SUPPORTED \
842 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
843 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES)
844
blkdev_fallocate(struct file * file,int mode,loff_t start,loff_t len)845 static long blkdev_fallocate(struct file *file, int mode, loff_t start,
846 loff_t len)
847 {
848 struct inode *inode = bdev_file_inode(file);
849 struct block_device *bdev = I_BDEV(inode);
850 loff_t end = start + len - 1;
851 loff_t isize;
852 unsigned int flags;
853 int error;
854
855 /* Fail if we don't recognize the flags. */
856 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
857 return -EOPNOTSUPP;
858 /*
859 * Don't allow writing zeroes if the device does not enable the
860 * unmap write zeroes operation.
861 */
862 if ((mode & FALLOC_FL_WRITE_ZEROES) &&
863 !bdev_write_zeroes_unmap_sectors(bdev))
864 return -EOPNOTSUPP;
865
866 /* Don't go off the end of the device. */
867 isize = bdev_nr_bytes(bdev);
868 if (start >= isize)
869 return -EINVAL;
870 if (end >= isize) {
871 if (mode & FALLOC_FL_KEEP_SIZE) {
872 len = isize - start;
873 end = start + len - 1;
874 } else
875 return -EINVAL;
876 }
877
878 /*
879 * Don't allow IO that isn't aligned to logical block size.
880 */
881 if ((start | len) & (bdev_logical_block_size(bdev) - 1))
882 return -EINVAL;
883
884 inode_lock(inode);
885 filemap_invalidate_lock(inode->i_mapping);
886
887 switch (mode) {
888 case FALLOC_FL_ZERO_RANGE:
889 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
890 flags = BLKDEV_ZERO_NOUNMAP;
891 break;
892 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
893 flags = BLKDEV_ZERO_NOFALLBACK;
894 break;
895 case FALLOC_FL_WRITE_ZEROES:
896 flags = 0;
897 break;
898 default:
899 error = -EOPNOTSUPP;
900 goto fail;
901 }
902
903 /*
904 * Invalidate the page cache, including dirty pages, for valid
905 * de-allocate mode calls to fallocate().
906 */
907 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
908 if (error)
909 goto fail;
910
911 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
912 len >> SECTOR_SHIFT, GFP_KERNEL, flags);
913 fail:
914 filemap_invalidate_unlock(inode->i_mapping);
915 inode_unlock(inode);
916 return error;
917 }
918
blkdev_mmap_prepare(struct vm_area_desc * desc)919 static int blkdev_mmap_prepare(struct vm_area_desc *desc)
920 {
921 struct file *file = desc->file;
922
923 if (bdev_read_only(I_BDEV(bdev_file_inode(file))))
924 return generic_file_readonly_mmap_prepare(desc);
925
926 return generic_file_mmap_prepare(desc);
927 }
928
929 const struct file_operations def_blk_fops = {
930 .open = blkdev_open,
931 .release = blkdev_release,
932 .llseek = blkdev_llseek,
933 .read_iter = blkdev_read_iter,
934 .write_iter = blkdev_write_iter,
935 .iopoll = iocb_bio_iopoll,
936 .mmap_prepare = blkdev_mmap_prepare,
937 .fsync = blkdev_fsync,
938 .unlocked_ioctl = blkdev_ioctl,
939 #ifdef CONFIG_COMPAT
940 .compat_ioctl = compat_blkdev_ioctl,
941 #endif
942 .splice_read = filemap_splice_read,
943 .splice_write = iter_file_splice_write,
944 .fallocate = blkdev_fallocate,
945 .uring_cmd = blkdev_uring_cmd,
946 .fop_flags = FOP_BUFFER_RASYNC | FOP_DONTCACHE,
947 };
948
blkdev_init(void)949 static __init int blkdev_init(void)
950 {
951 return bioset_init(&blkdev_dio_pool, 4,
952 offsetof(struct blkdev_dio, bio),
953 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
954 }
955 module_init(blkdev_init);
956