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, BIO_MAX_SIZE,
50 bdev_dma_alignment(bdev),
51 bdev_logical_block_size(bdev) - 1);
52 }
53
54 #define DIO_INLINE_BIO_VECS 4
55
__blkdev_direct_IO_simple(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)56 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
57 struct iov_iter *iter, struct block_device *bdev,
58 unsigned int nr_pages)
59 {
60 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
61 loff_t pos = iocb->ki_pos;
62 bool should_dirty = false;
63 struct bio bio;
64 ssize_t ret;
65
66 if (nr_pages <= DIO_INLINE_BIO_VECS)
67 vecs = inline_vecs;
68 else {
69 vecs = kmalloc_objs(struct bio_vec, nr_pages);
70 if (!vecs)
71 return -ENOMEM;
72 }
73
74 if (iov_iter_rw(iter) == READ) {
75 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
76 if (user_backed_iter(iter))
77 should_dirty = true;
78 } else {
79 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
80 }
81 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
82 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
83 bio.bi_write_stream = iocb->ki_write_stream;
84 bio.bi_ioprio = iocb->ki_ioprio;
85 if (iocb->ki_flags & IOCB_ATOMIC)
86 bio.bi_opf |= REQ_ATOMIC;
87
88 ret = blkdev_iov_iter_get_pages(&bio, iter, bdev);
89 if (unlikely(ret))
90 goto out;
91 ret = bio.bi_iter.bi_size;
92
93 if (iov_iter_rw(iter) == WRITE)
94 task_io_account_write(ret);
95
96 if (iocb->ki_flags & IOCB_NOWAIT)
97 bio.bi_opf |= REQ_NOWAIT;
98
99 submit_bio_wait(&bio);
100
101 bio_release_pages(&bio, should_dirty);
102 if (unlikely(bio.bi_status))
103 ret = blk_status_to_errno(bio.bi_status);
104
105 out:
106 if (vecs != inline_vecs)
107 kfree(vecs);
108
109 bio_uninit(&bio);
110
111 return ret;
112 }
113
114 enum {
115 DIO_SHOULD_DIRTY = 1,
116 DIO_IS_SYNC = 2,
117 };
118
119 struct blkdev_dio {
120 union {
121 struct kiocb *iocb;
122 struct task_struct *waiter;
123 };
124 size_t size;
125 atomic_t ref;
126 unsigned int flags;
127 struct bio bio ____cacheline_aligned_in_smp;
128 };
129
130 static struct bio_set blkdev_dio_pool;
131
blkdev_bio_end_io(struct bio * bio)132 static void blkdev_bio_end_io(struct bio *bio)
133 {
134 struct blkdev_dio *dio = bio->bi_private;
135 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
136 bool is_sync = dio->flags & DIO_IS_SYNC;
137
138 if (bio->bi_status && !dio->bio.bi_status)
139 dio->bio.bi_status = bio->bi_status;
140
141 if (bio_integrity(bio))
142 bio_integrity_unmap_user(bio);
143
144 if (atomic_dec_and_test(&dio->ref)) {
145 if (!is_sync) {
146 struct kiocb *iocb = dio->iocb;
147 ssize_t ret;
148
149 WRITE_ONCE(iocb->private, NULL);
150
151 if (likely(!dio->bio.bi_status)) {
152 ret = dio->size;
153 iocb->ki_pos += ret;
154 } else {
155 ret = blk_status_to_errno(dio->bio.bi_status);
156 }
157
158 dio->iocb->ki_complete(iocb, ret);
159 bio_put(&dio->bio);
160 } else {
161 struct task_struct *waiter = dio->waiter;
162
163 WRITE_ONCE(dio->waiter, NULL);
164 blk_wake_io_task(waiter);
165 }
166 }
167
168 if (should_dirty) {
169 bio_check_pages_dirty(bio);
170 } else {
171 bio_release_pages(bio, false);
172 bio_put(bio);
173 }
174 }
175
__blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)176 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
177 struct block_device *bdev, unsigned int nr_pages)
178 {
179 struct blk_plug plug;
180 struct blkdev_dio *dio;
181 struct bio *bio;
182 bool is_read = (iov_iter_rw(iter) == READ), is_sync;
183 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
184 loff_t pos = iocb->ki_pos;
185 int ret = 0;
186
187 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
188 &blkdev_dio_pool);
189 dio = container_of(bio, struct blkdev_dio, bio);
190 atomic_set(&dio->ref, 1);
191 /*
192 * Grab an extra reference to ensure the dio structure which is embedded
193 * into the first bio stays around.
194 */
195 bio_get(bio);
196
197 is_sync = is_sync_kiocb(iocb);
198 if (is_sync) {
199 dio->flags = DIO_IS_SYNC;
200 dio->waiter = current;
201 } else {
202 dio->flags = 0;
203 dio->iocb = iocb;
204 }
205
206 dio->size = 0;
207 if (is_read && user_backed_iter(iter))
208 dio->flags |= DIO_SHOULD_DIRTY;
209
210 blk_start_plug(&plug);
211
212 for (;;) {
213 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
214 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
215 bio->bi_write_stream = iocb->ki_write_stream;
216 bio->bi_private = dio;
217 bio->bi_end_io = blkdev_bio_end_io;
218 bio->bi_ioprio = iocb->ki_ioprio;
219
220 ret = blkdev_iov_iter_get_pages(bio, iter, bdev);
221 if (unlikely(ret)) {
222 bio_endio_status(bio, errno_to_blk_status(ret));
223 break;
224 }
225 if (iocb->ki_flags & IOCB_NOWAIT) {
226 /*
227 * This is nonblocking IO, and we need to allocate
228 * another bio if we have data left to map. As we
229 * cannot guarantee that one of the sub bios will not
230 * fail getting issued FOR NOWAIT and as error results
231 * are coalesced across all of them, be safe and ask for
232 * a retry of this from blocking context.
233 */
234 if (unlikely(iov_iter_count(iter))) {
235 ret = -EAGAIN;
236 goto fail;
237 }
238 bio->bi_opf |= REQ_NOWAIT;
239 }
240 if (iocb->ki_flags & IOCB_HAS_METADATA) {
241 ret = bio_integrity_map_iter(bio, iocb->private);
242 if (unlikely(ret)) {
243 bio_endio_status(bio, errno_to_blk_status(ret));
244 break;
245 }
246 }
247
248 if (is_read) {
249 if (dio->flags & DIO_SHOULD_DIRTY)
250 bio_set_pages_dirty(bio);
251 } else {
252 task_io_account_write(bio->bi_iter.bi_size);
253 }
254 dio->size += bio->bi_iter.bi_size;
255 pos += bio->bi_iter.bi_size;
256
257 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
258 if (!nr_pages) {
259 submit_bio(bio);
260 break;
261 }
262 atomic_inc(&dio->ref);
263 submit_bio(bio);
264 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
265 }
266
267 blk_finish_plug(&plug);
268
269 if (!is_sync)
270 return -EIOCBQUEUED;
271
272 for (;;) {
273 set_current_state(TASK_UNINTERRUPTIBLE);
274 if (!READ_ONCE(dio->waiter))
275 break;
276 blk_io_schedule();
277 }
278 __set_current_state(TASK_RUNNING);
279
280 if (!ret)
281 ret = blk_status_to_errno(dio->bio.bi_status);
282 if (likely(!ret))
283 ret = dio->size;
284
285 bio_put(&dio->bio);
286 return ret;
287 fail:
288 bio_release_pages(bio, false);
289 bio_clear_flag(bio, BIO_REFFED);
290 bio_put(bio);
291 blk_finish_plug(&plug);
292 return ret;
293 }
294
blkdev_bio_end_io_async(struct bio * bio)295 static void blkdev_bio_end_io_async(struct bio *bio)
296 {
297 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
298 struct kiocb *iocb = dio->iocb;
299 ssize_t ret;
300
301 WRITE_ONCE(iocb->private, NULL);
302
303 if (likely(!bio->bi_status)) {
304 ret = dio->size;
305 iocb->ki_pos += ret;
306 } else {
307 ret = blk_status_to_errno(bio->bi_status);
308 }
309
310 if (bio_integrity(bio))
311 bio_integrity_unmap_user(bio);
312
313 iocb->ki_complete(iocb, ret);
314
315 if (dio->flags & DIO_SHOULD_DIRTY) {
316 bio_check_pages_dirty(bio);
317 } else {
318 bio_release_pages(bio, false);
319 bio_put(bio);
320 }
321 }
322
__blkdev_direct_IO_async(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)323 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
324 struct iov_iter *iter,
325 struct block_device *bdev,
326 unsigned int nr_pages)
327 {
328 bool is_read = iov_iter_rw(iter) == READ;
329 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
330 struct blkdev_dio *dio;
331 struct bio *bio;
332 loff_t pos = iocb->ki_pos;
333 int ret = 0;
334
335 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
336 &blkdev_dio_pool);
337 dio = container_of(bio, struct blkdev_dio, bio);
338 dio->flags = 0;
339 dio->iocb = iocb;
340 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
341 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
342 bio->bi_write_stream = iocb->ki_write_stream;
343 bio->bi_end_io = blkdev_bio_end_io_async;
344 bio->bi_ioprio = iocb->ki_ioprio;
345
346 /*
347 * Users don't rely on the iterator being in any particular
348 * state for async I/O returning -EIOCBQUEUED, hence we can
349 * avoid expensive iov_iter_advance(). Bypass
350 * bio_iov_iter_get_pages() and set the bvec directly.
351 */
352 if (!bio_iov_iter_set(bio, iter)) {
353 ret = blkdev_iov_iter_get_pages(bio, iter, bdev);
354 if (unlikely(ret))
355 goto out_bio_put;
356 }
357 dio->size = bio->bi_iter.bi_size;
358
359 if (is_read) {
360 if (user_backed_iter(iter)) {
361 dio->flags |= DIO_SHOULD_DIRTY;
362 bio_set_pages_dirty(bio);
363 }
364 } else {
365 task_io_account_write(bio->bi_iter.bi_size);
366 }
367
368 if (iocb->ki_flags & IOCB_HAS_METADATA) {
369 ret = bio_integrity_map_iter(bio, iocb->private);
370 WRITE_ONCE(iocb->private, NULL);
371 if (unlikely(ret))
372 goto out_bio_put;
373 }
374
375 if (iocb->ki_flags & IOCB_ATOMIC)
376 bio->bi_opf |= REQ_ATOMIC;
377
378 if (iocb->ki_flags & IOCB_NOWAIT)
379 bio->bi_opf |= REQ_NOWAIT;
380
381 if (iocb->ki_flags & IOCB_HIPRI) {
382 bio->bi_opf |= REQ_POLLED;
383 submit_bio(bio);
384 WRITE_ONCE(iocb->private, bio);
385 } else {
386 submit_bio(bio);
387 }
388 return -EIOCBQUEUED;
389
390 out_bio_put:
391 bio_put(bio);
392 return ret;
393 }
394
blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter)395 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
396 {
397 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
398 unsigned int nr_pages;
399
400 if (!iov_iter_count(iter))
401 return 0;
402
403 if (blkdev_dio_invalid(bdev, iocb, iter))
404 return -EINVAL;
405
406 /* HIPRI needs private as bio; HAS_METADATA keeps it as uio_meta */
407 if ((iocb->ki_flags & IOCB_HIPRI) &&
408 (iocb->ki_flags & IOCB_HAS_METADATA))
409 return -EOPNOTSUPP;
410
411 if (iov_iter_rw(iter) == WRITE) {
412 u16 max_write_streams = bdev_max_write_streams(bdev);
413
414 if (iocb->ki_write_stream) {
415 if (iocb->ki_write_stream > max_write_streams)
416 return -EINVAL;
417 } else if (max_write_streams) {
418 enum rw_hint write_hint =
419 file_inode(iocb->ki_filp)->i_write_hint;
420
421 /*
422 * Just use the write hint as write stream for block
423 * device writes. This assumes no file system is
424 * mounted that would use the streams differently.
425 */
426 if (write_hint <= max_write_streams)
427 iocb->ki_write_stream = write_hint;
428 }
429 }
430
431 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
432 if (likely(nr_pages <= BIO_MAX_VECS &&
433 !(iocb->ki_flags & IOCB_HAS_METADATA))) {
434 if (is_sync_kiocb(iocb))
435 return __blkdev_direct_IO_simple(iocb, iter, bdev,
436 nr_pages);
437 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);
438 } else if (iocb->ki_flags & IOCB_ATOMIC) {
439 return -EINVAL;
440 }
441 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));
442 }
443
blkdev_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned int flags,struct iomap * iomap,struct iomap * srcmap)444 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
445 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
446 {
447 struct block_device *bdev = I_BDEV(inode);
448 loff_t isize = i_size_read(inode);
449
450 if (offset >= isize)
451 return -EIO;
452
453 iomap->bdev = bdev;
454 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
455 iomap->type = IOMAP_MAPPED;
456 iomap->addr = iomap->offset;
457 iomap->length = isize - iomap->offset;
458 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
459 return 0;
460 }
461
462 static DEFINE_IOMAP_ITER_NEXT(blkdev_iomap_next, blkdev_iomap_begin);
463
464 static const struct iomap_ops blkdev_iomap_ops = {
465 .iomap_next = blkdev_iomap_next,
466 };
467
468 #ifdef CONFIG_BUFFER_HEAD
blkdev_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)469 static int blkdev_get_block(struct inode *inode, sector_t iblock,
470 struct buffer_head *bh, int create)
471 {
472 bh->b_bdev = I_BDEV(inode);
473 bh->b_blocknr = iblock;
474 set_buffer_mapped(bh);
475 return 0;
476 }
477
478 /*
479 * We cannot call mpage_writepages() as it does not take the buffer lock.
480 * We must use block_write_full_folio() directly which holds the buffer
481 * lock. The buffer lock provides the synchronisation with writeback
482 * that filesystems rely on when they use the blockdev's mapping.
483 */
blkdev_writepages(struct address_space * mapping,struct writeback_control * wbc)484 static int blkdev_writepages(struct address_space *mapping,
485 struct writeback_control *wbc)
486 {
487 struct folio *folio = NULL;
488 struct blk_plug plug;
489 int err;
490
491 blk_start_plug(&plug);
492 while ((folio = writeback_iter(mapping, wbc, folio, &err)))
493 err = block_write_full_folio(folio, wbc, blkdev_get_block);
494 blk_finish_plug(&plug);
495
496 return err;
497 }
498
blkdev_read_folio(struct file * file,struct folio * folio)499 static int blkdev_read_folio(struct file *file, struct folio *folio)
500 {
501 return block_read_full_folio(folio, blkdev_get_block);
502 }
503
blkdev_readahead(struct readahead_control * rac)504 static void blkdev_readahead(struct readahead_control *rac)
505 {
506 mpage_readahead(rac, blkdev_get_block);
507 }
508
509 const struct address_space_operations def_blk_aops = {
510 .dirty_folio = block_dirty_folio,
511 .invalidate_folio = block_invalidate_folio,
512 .read_folio = blkdev_read_folio,
513 .readahead = blkdev_readahead,
514 .writepages = blkdev_writepages,
515 .migrate_folio = buffer_migrate_folio_norefs,
516 .is_dirty_writeback = buffer_check_dirty_writeback,
517 };
518 #else /* CONFIG_BUFFER_HEAD */
blkdev_read_folio(struct file * file,struct folio * folio)519 static int blkdev_read_folio(struct file *file, struct folio *folio)
520 {
521 iomap_bio_read_folio(folio, &blkdev_iomap_ops);
522 return 0;
523 }
524
blkdev_readahead(struct readahead_control * rac)525 static void blkdev_readahead(struct readahead_control *rac)
526 {
527 iomap_bio_readahead(rac, &blkdev_iomap_ops);
528 }
529
blkdev_writeback_range(struct iomap_writepage_ctx * wpc,struct folio * folio,u64 offset,unsigned int len,u64 end_pos)530 static ssize_t blkdev_writeback_range(struct iomap_writepage_ctx *wpc,
531 struct folio *folio, u64 offset, unsigned int len, u64 end_pos)
532 {
533 loff_t isize = i_size_read(wpc->inode);
534
535 if (WARN_ON_ONCE(offset >= isize))
536 return -EIO;
537
538 if (offset < wpc->iomap.offset ||
539 offset >= wpc->iomap.offset + wpc->iomap.length) {
540 int error;
541
542 error = blkdev_iomap_begin(wpc->inode, offset, isize - offset,
543 IOMAP_WRITE, &wpc->iomap, NULL);
544 if (error)
545 return error;
546 }
547
548 return iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
549 }
550
551 static const struct iomap_writeback_ops blkdev_writeback_ops = {
552 .writeback_range = blkdev_writeback_range,
553 .writeback_submit = iomap_ioend_writeback_submit,
554 };
555
blkdev_writepages(struct address_space * mapping,struct writeback_control * wbc)556 static int blkdev_writepages(struct address_space *mapping,
557 struct writeback_control *wbc)
558 {
559 struct iomap_writepage_ctx wpc = {
560 .inode = mapping->host,
561 .wbc = wbc,
562 .ops = &blkdev_writeback_ops
563 };
564
565 return iomap_writepages(&wpc);
566 }
567
568 const struct address_space_operations def_blk_aops = {
569 .dirty_folio = filemap_dirty_folio,
570 .release_folio = iomap_release_folio,
571 .invalidate_folio = iomap_invalidate_folio,
572 .read_folio = blkdev_read_folio,
573 .readahead = blkdev_readahead,
574 .writepages = blkdev_writepages,
575 .is_partially_uptodate = iomap_is_partially_uptodate,
576 .error_remove_folio = generic_error_remove_folio,
577 .migrate_folio = filemap_migrate_folio,
578 };
579 #endif /* CONFIG_BUFFER_HEAD */
580
581 /*
582 * for a block special file file_inode(file)->i_size is zero
583 * so we compute the size by hand (just as in block_read/write above)
584 */
blkdev_llseek(struct file * file,loff_t offset,int whence)585 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
586 {
587 struct inode *bd_inode = bdev_file_inode(file);
588 loff_t retval;
589
590 inode_lock(bd_inode);
591 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
592 inode_unlock(bd_inode);
593 return retval;
594 }
595
blkdev_fsync(struct file * filp,loff_t start,loff_t end,int datasync)596 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
597 int datasync)
598 {
599 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
600 int error;
601
602 error = file_write_and_wait_range(filp, start, end);
603 if (error)
604 return error;
605
606 /*
607 * There is no need to serialise calls to blkdev_issue_flush with
608 * i_mutex and doing so causes performance issues with concurrent
609 * O_SYNC writers to a block device.
610 */
611 error = blkdev_issue_flush(bdev);
612 if (error == -EOPNOTSUPP)
613 error = 0;
614
615 return error;
616 }
617
618 /**
619 * file_to_blk_mode - get block open flags from file flags
620 * @file: file whose open flags should be converted
621 *
622 * Look at file open flags and generate corresponding block open flags from
623 * them. The function works both for file just being open (e.g. during ->open
624 * callback) and for file that is already open. This is actually non-trivial
625 * (see comment in the function).
626 */
file_to_blk_mode(struct file * file)627 blk_mode_t file_to_blk_mode(struct file *file)
628 {
629 blk_mode_t mode = 0;
630
631 if (file->f_mode & FMODE_READ)
632 mode |= BLK_OPEN_READ;
633 if (file->f_mode & FMODE_WRITE)
634 mode |= BLK_OPEN_WRITE;
635 /*
636 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data
637 * to determine whether the open was exclusive for already open files.
638 */
639 if (file->private_data)
640 mode |= BLK_OPEN_EXCL;
641 else if (file->f_flags & O_EXCL)
642 mode |= BLK_OPEN_EXCL;
643 if (file->f_flags & O_NDELAY)
644 mode |= BLK_OPEN_NDELAY;
645
646 /*
647 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
648 * driver has historically allowed ioctls as if the file was opened for
649 * writing, but does not allow and actual reads or writes.
650 */
651 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
652 mode |= BLK_OPEN_WRITE_IOCTL;
653
654 return mode;
655 }
656
blkdev_open(struct inode * inode,struct file * filp)657 static int blkdev_open(struct inode *inode, struct file *filp)
658 {
659 struct block_device *bdev;
660 blk_mode_t mode;
661 int ret;
662
663 mode = file_to_blk_mode(filp);
664 /* Use the file as the holder. */
665 if (mode & BLK_OPEN_EXCL)
666 filp->private_data = filp;
667 ret = bdev_permission(inode->i_rdev, mode, filp->private_data);
668 if (ret)
669 return ret;
670
671 bdev = blkdev_get_no_open(inode->i_rdev, true);
672 if (!bdev)
673 return -ENXIO;
674
675 if (bdev_can_atomic_write(bdev))
676 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;
677 if (blk_get_integrity(bdev->bd_disk))
678 filp->f_mode |= FMODE_HAS_METADATA;
679
680 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp);
681 if (ret)
682 blkdev_put_no_open(bdev);
683 return ret;
684 }
685
blkdev_release(struct inode * inode,struct file * filp)686 static int blkdev_release(struct inode *inode, struct file *filp)
687 {
688 bdev_release(filp);
689 return 0;
690 }
691
692 static ssize_t
blkdev_direct_write(struct kiocb * iocb,struct iov_iter * from)693 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
694 {
695 size_t count = iov_iter_count(from);
696 ssize_t written;
697
698 written = kiocb_invalidate_pages(iocb, count);
699 if (written) {
700 if (written == -EBUSY)
701 return 0;
702 return written;
703 }
704
705 written = blkdev_direct_IO(iocb, from);
706 if (written > 0) {
707 kiocb_invalidate_post_direct_write(iocb, count);
708 iocb->ki_pos += written;
709 count -= written;
710 }
711 if (written != -EIOCBQUEUED)
712 iov_iter_revert(from, count - iov_iter_count(from));
713 return written;
714 }
715
blkdev_buffered_write(struct kiocb * iocb,struct iov_iter * from)716 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
717 {
718 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL,
719 NULL);
720 }
721
722 /*
723 * Write data to the block device. Only intended for the block device itself
724 * and the raw driver which basically is a fake block device.
725 *
726 * Does not take i_mutex for the write and thus is not for general purpose
727 * use.
728 */
blkdev_write_iter(struct kiocb * iocb,struct iov_iter * from)729 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
730 {
731 struct file *file = iocb->ki_filp;
732 struct inode *bd_inode = bdev_file_inode(file);
733 struct block_device *bdev = I_BDEV(bd_inode);
734 bool atomic = iocb->ki_flags & IOCB_ATOMIC;
735 loff_t size = bdev_nr_bytes(bdev);
736 size_t shorted = 0;
737 ssize_t ret;
738
739 if (bdev_read_only(bdev))
740 return -EPERM;
741
742 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
743 return -ETXTBSY;
744
745 if (!iov_iter_count(from))
746 return 0;
747
748 if (iocb->ki_pos >= size)
749 return -ENOSPC;
750
751 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
752 return -EOPNOTSUPP;
753
754 if (atomic) {
755 ret = generic_atomic_write_valid(iocb, from);
756 if (ret)
757 return ret;
758 }
759
760 size -= iocb->ki_pos;
761 if (iov_iter_count(from) > size) {
762 if (atomic)
763 return -EINVAL;
764 shorted = iov_iter_count(from) - size;
765 iov_iter_truncate(from, size);
766 }
767
768 ret = file_update_time(file);
769 if (ret)
770 return ret;
771
772 if (iocb->ki_flags & IOCB_DIRECT) {
773 ret = blkdev_direct_write(iocb, from);
774 if (ret >= 0 && iov_iter_count(from))
775 ret = direct_write_fallback(iocb, from, ret,
776 blkdev_buffered_write(iocb, from));
777 } else {
778 /*
779 * Take i_rwsem and invalidate_lock to avoid racing with
780 * set_blocksize changing i_blkbits/folio order and punching
781 * out the pagecache.
782 */
783 inode_lock_shared(bd_inode);
784 ret = blkdev_buffered_write(iocb, from);
785 inode_unlock_shared(bd_inode);
786 }
787
788 if (ret > 0)
789 ret = generic_write_sync(iocb, ret);
790 iov_iter_reexpand(from, iov_iter_count(from) + shorted);
791 return ret;
792 }
793
blkdev_read_iter(struct kiocb * iocb,struct iov_iter * to)794 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
795 {
796 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp);
797 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
798 loff_t size = bdev_nr_bytes(bdev);
799 loff_t pos = iocb->ki_pos;
800 size_t shorted = 0;
801 ssize_t ret = 0;
802 size_t count;
803
804 if (unlikely(pos + iov_iter_count(to) > size)) {
805 if (pos >= size)
806 return 0;
807 size -= pos;
808 shorted = iov_iter_count(to) - size;
809 iov_iter_truncate(to, size);
810 }
811
812 count = iov_iter_count(to);
813 if (!count)
814 goto reexpand; /* skip atime */
815
816 if (iocb->ki_flags & IOCB_DIRECT) {
817 ret = kiocb_write_and_wait(iocb, count);
818 if (ret < 0)
819 goto reexpand;
820 file_accessed(iocb->ki_filp);
821
822 ret = blkdev_direct_IO(iocb, to);
823 if (ret > 0) {
824 iocb->ki_pos += ret;
825 count -= ret;
826 }
827 if (ret != -EIOCBQUEUED)
828 iov_iter_revert(to, count - iov_iter_count(to));
829 if (ret < 0 || !count)
830 goto reexpand;
831 }
832
833 /*
834 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize
835 * changing i_blkbits/folio order and punching out the pagecache.
836 */
837 inode_lock_shared(bd_inode);
838 ret = filemap_read(iocb, to, ret);
839 inode_unlock_shared(bd_inode);
840
841 reexpand:
842 if (unlikely(shorted))
843 iov_iter_reexpand(to, iov_iter_count(to) + shorted);
844 return ret;
845 }
846
847 #define BLKDEV_FALLOC_FL_SUPPORTED \
848 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
849 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES)
850
blkdev_fallocate(struct file * file,int mode,loff_t start,loff_t len)851 static long blkdev_fallocate(struct file *file, int mode, loff_t start,
852 loff_t len)
853 {
854 struct inode *inode = bdev_file_inode(file);
855 struct block_device *bdev = I_BDEV(inode);
856 loff_t end = start + len - 1;
857 loff_t isize;
858 unsigned int flags;
859 int error;
860
861 /* Fail if we don't recognize the flags. */
862 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
863 return -EOPNOTSUPP;
864 /*
865 * Don't allow writing zeroes if the device does not enable the
866 * unmap write zeroes operation.
867 */
868 if ((mode & FALLOC_FL_WRITE_ZEROES) &&
869 !bdev_write_zeroes_unmap_sectors(bdev))
870 return -EOPNOTSUPP;
871
872 /* Don't go off the end of the device. */
873 isize = bdev_nr_bytes(bdev);
874 if (start >= isize)
875 return -EINVAL;
876 if (end >= isize) {
877 if (mode & FALLOC_FL_KEEP_SIZE) {
878 len = isize - start;
879 end = start + len - 1;
880 } else
881 return -EINVAL;
882 }
883
884 /*
885 * Don't allow IO that isn't aligned to logical block size.
886 */
887 if ((start | len) & (bdev_logical_block_size(bdev) - 1))
888 return -EINVAL;
889
890 inode_lock(inode);
891 filemap_invalidate_lock(inode->i_mapping);
892
893 switch (mode) {
894 case FALLOC_FL_ZERO_RANGE:
895 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
896 flags = BLKDEV_ZERO_NOUNMAP;
897 break;
898 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
899 flags = BLKDEV_ZERO_NOFALLBACK;
900 break;
901 case FALLOC_FL_WRITE_ZEROES:
902 flags = 0;
903 break;
904 default:
905 error = -EOPNOTSUPP;
906 goto fail;
907 }
908
909 /*
910 * Invalidate the page cache, including dirty pages, for valid
911 * de-allocate mode calls to fallocate().
912 */
913 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
914 if (error)
915 goto fail;
916
917 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
918 len >> SECTOR_SHIFT, GFP_KERNEL, flags);
919 fail:
920 filemap_invalidate_unlock(inode->i_mapping);
921 inode_unlock(inode);
922 return error;
923 }
924
blkdev_mmap_prepare(struct vm_area_desc * desc)925 static int blkdev_mmap_prepare(struct vm_area_desc *desc)
926 {
927 struct file *file = desc->file;
928
929 if (bdev_read_only(I_BDEV(bdev_file_inode(file))))
930 return generic_file_readonly_mmap_prepare(desc);
931
932 return generic_file_mmap_prepare(desc);
933 }
934
935 const struct file_operations def_blk_fops = {
936 .open = blkdev_open,
937 .release = blkdev_release,
938 .llseek = blkdev_llseek,
939 .read_iter = blkdev_read_iter,
940 .write_iter = blkdev_write_iter,
941 .iopoll = iocb_bio_iopoll,
942 .mmap_prepare = blkdev_mmap_prepare,
943 .fsync = blkdev_fsync,
944 .unlocked_ioctl = blkdev_ioctl,
945 #ifdef CONFIG_COMPAT
946 .compat_ioctl = compat_blkdev_ioctl,
947 #endif
948 .splice_read = filemap_splice_read,
949 .splice_write = iter_file_splice_write,
950 .fallocate = blkdev_fallocate,
951 .uring_cmd = blkdev_uring_cmd,
952 .fop_flags = FOP_BUFFER_RASYNC | FOP_DONTCACHE,
953 };
954
blkdev_init(void)955 static __init int blkdev_init(void)
956 {
957 return bioset_init(&blkdev_dio_pool, 4,
958 offsetof(struct blkdev_dio, bio),
959 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
960 }
961 module_init(blkdev_init);
962