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 & (bdev_logical_block_size(bdev) - 1) ||
43 !bdev_iter_is_aligned(bdev, iter);
44 }
45
46 #define DIO_INLINE_BIO_VECS 4
47
__blkdev_direct_IO_simple(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)48 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
49 struct iov_iter *iter, struct block_device *bdev,
50 unsigned int nr_pages)
51 {
52 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
53 loff_t pos = iocb->ki_pos;
54 bool should_dirty = false;
55 struct bio bio;
56 ssize_t ret;
57
58 if (nr_pages <= DIO_INLINE_BIO_VECS)
59 vecs = inline_vecs;
60 else {
61 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),
62 GFP_KERNEL);
63 if (!vecs)
64 return -ENOMEM;
65 }
66
67 if (iov_iter_rw(iter) == READ) {
68 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
69 if (user_backed_iter(iter))
70 should_dirty = true;
71 } else {
72 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
73 }
74 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
75 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
76 bio.bi_write_stream = iocb->ki_write_stream;
77 bio.bi_ioprio = iocb->ki_ioprio;
78 if (iocb->ki_flags & IOCB_ATOMIC)
79 bio.bi_opf |= REQ_ATOMIC;
80
81 ret = bio_iov_iter_get_pages(&bio, iter);
82 if (unlikely(ret))
83 goto out;
84 ret = bio.bi_iter.bi_size;
85
86 if (iov_iter_rw(iter) == WRITE)
87 task_io_account_write(ret);
88
89 if (iocb->ki_flags & IOCB_NOWAIT)
90 bio.bi_opf |= REQ_NOWAIT;
91
92 submit_bio_wait(&bio);
93
94 bio_release_pages(&bio, should_dirty);
95 if (unlikely(bio.bi_status))
96 ret = blk_status_to_errno(bio.bi_status);
97
98 out:
99 if (vecs != inline_vecs)
100 kfree(vecs);
101
102 bio_uninit(&bio);
103
104 return ret;
105 }
106
107 enum {
108 DIO_SHOULD_DIRTY = 1,
109 DIO_IS_SYNC = 2,
110 };
111
112 struct blkdev_dio {
113 union {
114 struct kiocb *iocb;
115 struct task_struct *waiter;
116 };
117 size_t size;
118 atomic_t ref;
119 unsigned int flags;
120 struct bio bio ____cacheline_aligned_in_smp;
121 };
122
123 static struct bio_set blkdev_dio_pool;
124
blkdev_bio_end_io(struct bio * bio)125 static void blkdev_bio_end_io(struct bio *bio)
126 {
127 struct blkdev_dio *dio = bio->bi_private;
128 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
129 bool is_sync = dio->flags & DIO_IS_SYNC;
130
131 if (bio->bi_status && !dio->bio.bi_status)
132 dio->bio.bi_status = bio->bi_status;
133
134 if (bio_integrity(bio))
135 bio_integrity_unmap_user(bio);
136
137 if (atomic_dec_and_test(&dio->ref)) {
138 if (!is_sync) {
139 struct kiocb *iocb = dio->iocb;
140 ssize_t ret;
141
142 WRITE_ONCE(iocb->private, NULL);
143
144 if (likely(!dio->bio.bi_status)) {
145 ret = dio->size;
146 iocb->ki_pos += ret;
147 } else {
148 ret = blk_status_to_errno(dio->bio.bi_status);
149 }
150
151 dio->iocb->ki_complete(iocb, ret);
152 bio_put(&dio->bio);
153 } else {
154 struct task_struct *waiter = dio->waiter;
155
156 WRITE_ONCE(dio->waiter, NULL);
157 blk_wake_io_task(waiter);
158 }
159 }
160
161 if (should_dirty) {
162 bio_check_pages_dirty(bio);
163 } else {
164 bio_release_pages(bio, false);
165 bio_put(bio);
166 }
167 }
168
__blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)169 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
170 struct block_device *bdev, unsigned int nr_pages)
171 {
172 struct blk_plug plug;
173 struct blkdev_dio *dio;
174 struct bio *bio;
175 bool is_read = (iov_iter_rw(iter) == READ), is_sync;
176 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
177 loff_t pos = iocb->ki_pos;
178 int ret = 0;
179
180 if (iocb->ki_flags & IOCB_ALLOC_CACHE)
181 opf |= REQ_ALLOC_CACHE;
182 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
183 &blkdev_dio_pool);
184 dio = container_of(bio, struct blkdev_dio, bio);
185 atomic_set(&dio->ref, 1);
186 /*
187 * Grab an extra reference to ensure the dio structure which is embedded
188 * into the first bio stays around.
189 */
190 bio_get(bio);
191
192 is_sync = is_sync_kiocb(iocb);
193 if (is_sync) {
194 dio->flags = DIO_IS_SYNC;
195 dio->waiter = current;
196 } else {
197 dio->flags = 0;
198 dio->iocb = iocb;
199 }
200
201 dio->size = 0;
202 if (is_read && user_backed_iter(iter))
203 dio->flags |= DIO_SHOULD_DIRTY;
204
205 blk_start_plug(&plug);
206
207 for (;;) {
208 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
209 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
210 bio->bi_write_stream = iocb->ki_write_stream;
211 bio->bi_private = dio;
212 bio->bi_end_io = blkdev_bio_end_io;
213 bio->bi_ioprio = iocb->ki_ioprio;
214
215 ret = bio_iov_iter_get_pages(bio, iter);
216 if (unlikely(ret)) {
217 bio->bi_status = BLK_STS_IOERR;
218 bio_endio(bio);
219 break;
220 }
221 if (iocb->ki_flags & IOCB_NOWAIT) {
222 /*
223 * This is nonblocking IO, and we need to allocate
224 * another bio if we have data left to map. As we
225 * cannot guarantee that one of the sub bios will not
226 * fail getting issued FOR NOWAIT and as error results
227 * are coalesced across all of them, be safe and ask for
228 * a retry of this from blocking context.
229 */
230 if (unlikely(iov_iter_count(iter))) {
231 ret = -EAGAIN;
232 goto fail;
233 }
234 bio->bi_opf |= REQ_NOWAIT;
235 }
236 if (iocb->ki_flags & IOCB_HAS_METADATA) {
237 ret = bio_integrity_map_iter(bio, iocb->private);
238 if (unlikely(ret))
239 goto fail;
240 }
241
242 if (is_read) {
243 if (dio->flags & DIO_SHOULD_DIRTY)
244 bio_set_pages_dirty(bio);
245 } else {
246 task_io_account_write(bio->bi_iter.bi_size);
247 }
248 dio->size += bio->bi_iter.bi_size;
249 pos += bio->bi_iter.bi_size;
250
251 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
252 if (!nr_pages) {
253 submit_bio(bio);
254 break;
255 }
256 atomic_inc(&dio->ref);
257 submit_bio(bio);
258 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
259 }
260
261 blk_finish_plug(&plug);
262
263 if (!is_sync)
264 return -EIOCBQUEUED;
265
266 for (;;) {
267 set_current_state(TASK_UNINTERRUPTIBLE);
268 if (!READ_ONCE(dio->waiter))
269 break;
270 blk_io_schedule();
271 }
272 __set_current_state(TASK_RUNNING);
273
274 if (!ret)
275 ret = blk_status_to_errno(dio->bio.bi_status);
276 if (likely(!ret))
277 ret = dio->size;
278
279 bio_put(&dio->bio);
280 return ret;
281 fail:
282 bio_release_pages(bio, false);
283 bio_clear_flag(bio, BIO_REFFED);
284 bio_put(bio);
285 blk_finish_plug(&plug);
286 return ret;
287 }
288
blkdev_bio_end_io_async(struct bio * bio)289 static void blkdev_bio_end_io_async(struct bio *bio)
290 {
291 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
292 struct kiocb *iocb = dio->iocb;
293 ssize_t ret;
294
295 WRITE_ONCE(iocb->private, NULL);
296
297 if (likely(!bio->bi_status)) {
298 ret = dio->size;
299 iocb->ki_pos += ret;
300 } else {
301 ret = blk_status_to_errno(bio->bi_status);
302 }
303
304 if (bio_integrity(bio))
305 bio_integrity_unmap_user(bio);
306
307 iocb->ki_complete(iocb, ret);
308
309 if (dio->flags & DIO_SHOULD_DIRTY) {
310 bio_check_pages_dirty(bio);
311 } else {
312 bio_release_pages(bio, false);
313 bio_put(bio);
314 }
315 }
316
__blkdev_direct_IO_async(struct kiocb * iocb,struct iov_iter * iter,struct block_device * bdev,unsigned int nr_pages)317 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
318 struct iov_iter *iter,
319 struct block_device *bdev,
320 unsigned int nr_pages)
321 {
322 bool is_read = iov_iter_rw(iter) == READ;
323 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
324 struct blkdev_dio *dio;
325 struct bio *bio;
326 loff_t pos = iocb->ki_pos;
327 int ret = 0;
328
329 if (iocb->ki_flags & IOCB_ALLOC_CACHE)
330 opf |= REQ_ALLOC_CACHE;
331 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
332 &blkdev_dio_pool);
333 dio = container_of(bio, struct blkdev_dio, bio);
334 dio->flags = 0;
335 dio->iocb = iocb;
336 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
337 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
338 bio->bi_write_stream = iocb->ki_write_stream;
339 bio->bi_end_io = blkdev_bio_end_io_async;
340 bio->bi_ioprio = iocb->ki_ioprio;
341
342 if (iov_iter_is_bvec(iter)) {
343 /*
344 * Users don't rely on the iterator being in any particular
345 * state for async I/O returning -EIOCBQUEUED, hence we can
346 * avoid expensive iov_iter_advance(). Bypass
347 * bio_iov_iter_get_pages() and set the bvec directly.
348 */
349 bio_iov_bvec_set(bio, iter);
350 } else {
351 ret = bio_iov_iter_get_pages(bio, iter);
352 if (unlikely(ret))
353 goto out_bio_put;
354 }
355 dio->size = bio->bi_iter.bi_size;
356
357 if (is_read) {
358 if (user_backed_iter(iter)) {
359 dio->flags |= DIO_SHOULD_DIRTY;
360 bio_set_pages_dirty(bio);
361 }
362 } else {
363 task_io_account_write(bio->bi_iter.bi_size);
364 }
365
366 if (iocb->ki_flags & IOCB_HAS_METADATA) {
367 ret = bio_integrity_map_iter(bio, iocb->private);
368 WRITE_ONCE(iocb->private, NULL);
369 if (unlikely(ret))
370 goto out_bio_put;
371 }
372
373 if (iocb->ki_flags & IOCB_ATOMIC)
374 bio->bi_opf |= REQ_ATOMIC;
375
376 if (iocb->ki_flags & IOCB_NOWAIT)
377 bio->bi_opf |= REQ_NOWAIT;
378
379 if (iocb->ki_flags & IOCB_HIPRI) {
380 bio->bi_opf |= REQ_POLLED;
381 submit_bio(bio);
382 WRITE_ONCE(iocb->private, bio);
383 } else {
384 submit_bio(bio);
385 }
386 return -EIOCBQUEUED;
387
388 out_bio_put:
389 bio_put(bio);
390 return ret;
391 }
392
blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter)393 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
394 {
395 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
396 unsigned int nr_pages;
397
398 if (!iov_iter_count(iter))
399 return 0;
400
401 if (blkdev_dio_invalid(bdev, iocb, iter))
402 return -EINVAL;
403
404 if (iov_iter_rw(iter) == WRITE) {
405 u16 max_write_streams = bdev_max_write_streams(bdev);
406
407 if (iocb->ki_write_stream) {
408 if (iocb->ki_write_stream > max_write_streams)
409 return -EINVAL;
410 } else if (max_write_streams) {
411 enum rw_hint write_hint =
412 file_inode(iocb->ki_filp)->i_write_hint;
413
414 /*
415 * Just use the write hint as write stream for block
416 * device writes. This assumes no file system is
417 * mounted that would use the streams differently.
418 */
419 if (write_hint <= max_write_streams)
420 iocb->ki_write_stream = write_hint;
421 }
422 }
423
424 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
425 if (likely(nr_pages <= BIO_MAX_VECS &&
426 !(iocb->ki_flags & IOCB_HAS_METADATA))) {
427 if (is_sync_kiocb(iocb))
428 return __blkdev_direct_IO_simple(iocb, iter, bdev,
429 nr_pages);
430 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);
431 } else if (iocb->ki_flags & IOCB_ATOMIC) {
432 return -EINVAL;
433 }
434 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));
435 }
436
blkdev_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned int flags,struct iomap * iomap,struct iomap * srcmap)437 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
438 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
439 {
440 struct block_device *bdev = I_BDEV(inode);
441 loff_t isize = i_size_read(inode);
442
443 if (offset >= isize)
444 return -EIO;
445
446 iomap->bdev = bdev;
447 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
448 iomap->type = IOMAP_MAPPED;
449 iomap->addr = iomap->offset;
450 iomap->length = isize - iomap->offset;
451 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
452 return 0;
453 }
454
455 static const struct iomap_ops blkdev_iomap_ops = {
456 .iomap_begin = blkdev_iomap_begin,
457 };
458
459 #ifdef CONFIG_BUFFER_HEAD
blkdev_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)460 static int blkdev_get_block(struct inode *inode, sector_t iblock,
461 struct buffer_head *bh, int create)
462 {
463 bh->b_bdev = I_BDEV(inode);
464 bh->b_blocknr = iblock;
465 set_buffer_mapped(bh);
466 return 0;
467 }
468
469 /*
470 * We cannot call mpage_writepages() as it does not take the buffer lock.
471 * We must use block_write_full_folio() directly which holds the buffer
472 * lock. The buffer lock provides the synchronisation with writeback
473 * that filesystems rely on when they use the blockdev's mapping.
474 */
blkdev_writepages(struct address_space * mapping,struct writeback_control * wbc)475 static int blkdev_writepages(struct address_space *mapping,
476 struct writeback_control *wbc)
477 {
478 struct folio *folio = NULL;
479 struct blk_plug plug;
480 int err;
481
482 blk_start_plug(&plug);
483 while ((folio = writeback_iter(mapping, wbc, folio, &err)))
484 err = block_write_full_folio(folio, wbc, blkdev_get_block);
485 blk_finish_plug(&plug);
486
487 return err;
488 }
489
blkdev_read_folio(struct file * file,struct folio * folio)490 static int blkdev_read_folio(struct file *file, struct folio *folio)
491 {
492 return block_read_full_folio(folio, blkdev_get_block);
493 }
494
blkdev_readahead(struct readahead_control * rac)495 static void blkdev_readahead(struct readahead_control *rac)
496 {
497 mpage_readahead(rac, blkdev_get_block);
498 }
499
blkdev_write_begin(const struct kiocb * iocb,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)500 static int blkdev_write_begin(const struct kiocb *iocb,
501 struct address_space *mapping, loff_t pos,
502 unsigned len, struct folio **foliop,
503 void **fsdata)
504 {
505 return block_write_begin(mapping, pos, len, foliop, blkdev_get_block);
506 }
507
blkdev_write_end(const struct kiocb * iocb,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)508 static int blkdev_write_end(const struct kiocb *iocb,
509 struct address_space *mapping,
510 loff_t pos, unsigned len, unsigned copied,
511 struct folio *folio, void *fsdata)
512 {
513 int ret;
514 ret = block_write_end(pos, len, copied, folio);
515
516 folio_unlock(folio);
517 folio_put(folio);
518
519 return ret;
520 }
521
522 const struct address_space_operations def_blk_aops = {
523 .dirty_folio = block_dirty_folio,
524 .invalidate_folio = block_invalidate_folio,
525 .read_folio = blkdev_read_folio,
526 .readahead = blkdev_readahead,
527 .writepages = blkdev_writepages,
528 .write_begin = blkdev_write_begin,
529 .write_end = blkdev_write_end,
530 .migrate_folio = buffer_migrate_folio_norefs,
531 .is_dirty_writeback = buffer_check_dirty_writeback,
532 };
533 #else /* CONFIG_BUFFER_HEAD */
blkdev_read_folio(struct file * file,struct folio * folio)534 static int blkdev_read_folio(struct file *file, struct folio *folio)
535 {
536 return iomap_read_folio(folio, &blkdev_iomap_ops);
537 }
538
blkdev_readahead(struct readahead_control * rac)539 static void blkdev_readahead(struct readahead_control *rac)
540 {
541 iomap_readahead(rac, &blkdev_iomap_ops);
542 }
543
blkdev_writeback_range(struct iomap_writepage_ctx * wpc,struct folio * folio,u64 offset,unsigned int len,u64 end_pos)544 static ssize_t blkdev_writeback_range(struct iomap_writepage_ctx *wpc,
545 struct folio *folio, u64 offset, unsigned int len, u64 end_pos)
546 {
547 loff_t isize = i_size_read(wpc->inode);
548
549 if (WARN_ON_ONCE(offset >= isize))
550 return -EIO;
551
552 if (offset < wpc->iomap.offset ||
553 offset >= wpc->iomap.offset + wpc->iomap.length) {
554 int error;
555
556 error = blkdev_iomap_begin(wpc->inode, offset, isize - offset,
557 IOMAP_WRITE, &wpc->iomap, NULL);
558 if (error)
559 return error;
560 }
561
562 return iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
563 }
564
565 static const struct iomap_writeback_ops blkdev_writeback_ops = {
566 .writeback_range = blkdev_writeback_range,
567 .writeback_submit = iomap_ioend_writeback_submit,
568 };
569
blkdev_writepages(struct address_space * mapping,struct writeback_control * wbc)570 static int blkdev_writepages(struct address_space *mapping,
571 struct writeback_control *wbc)
572 {
573 struct iomap_writepage_ctx wpc = {
574 .inode = mapping->host,
575 .wbc = wbc,
576 .ops = &blkdev_writeback_ops
577 };
578
579 return iomap_writepages(&wpc);
580 }
581
582 const struct address_space_operations def_blk_aops = {
583 .dirty_folio = filemap_dirty_folio,
584 .release_folio = iomap_release_folio,
585 .invalidate_folio = iomap_invalidate_folio,
586 .read_folio = blkdev_read_folio,
587 .readahead = blkdev_readahead,
588 .writepages = blkdev_writepages,
589 .is_partially_uptodate = iomap_is_partially_uptodate,
590 .error_remove_folio = generic_error_remove_folio,
591 .migrate_folio = filemap_migrate_folio,
592 };
593 #endif /* CONFIG_BUFFER_HEAD */
594
595 /*
596 * for a block special file file_inode(file)->i_size is zero
597 * so we compute the size by hand (just as in block_read/write above)
598 */
blkdev_llseek(struct file * file,loff_t offset,int whence)599 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
600 {
601 struct inode *bd_inode = bdev_file_inode(file);
602 loff_t retval;
603
604 inode_lock(bd_inode);
605 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
606 inode_unlock(bd_inode);
607 return retval;
608 }
609
blkdev_fsync(struct file * filp,loff_t start,loff_t end,int datasync)610 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
611 int datasync)
612 {
613 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
614 int error;
615
616 error = file_write_and_wait_range(filp, start, end);
617 if (error)
618 return error;
619
620 /*
621 * There is no need to serialise calls to blkdev_issue_flush with
622 * i_mutex and doing so causes performance issues with concurrent
623 * O_SYNC writers to a block device.
624 */
625 error = blkdev_issue_flush(bdev);
626 if (error == -EOPNOTSUPP)
627 error = 0;
628
629 return error;
630 }
631
632 /**
633 * file_to_blk_mode - get block open flags from file flags
634 * @file: file whose open flags should be converted
635 *
636 * Look at file open flags and generate corresponding block open flags from
637 * them. The function works both for file just being open (e.g. during ->open
638 * callback) and for file that is already open. This is actually non-trivial
639 * (see comment in the function).
640 */
file_to_blk_mode(struct file * file)641 blk_mode_t file_to_blk_mode(struct file *file)
642 {
643 blk_mode_t mode = 0;
644
645 if (file->f_mode & FMODE_READ)
646 mode |= BLK_OPEN_READ;
647 if (file->f_mode & FMODE_WRITE)
648 mode |= BLK_OPEN_WRITE;
649 /*
650 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data
651 * to determine whether the open was exclusive for already open files.
652 */
653 if (file->private_data)
654 mode |= BLK_OPEN_EXCL;
655 else if (file->f_flags & O_EXCL)
656 mode |= BLK_OPEN_EXCL;
657 if (file->f_flags & O_NDELAY)
658 mode |= BLK_OPEN_NDELAY;
659
660 /*
661 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
662 * driver has historically allowed ioctls as if the file was opened for
663 * writing, but does not allow and actual reads or writes.
664 */
665 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
666 mode |= BLK_OPEN_WRITE_IOCTL;
667
668 return mode;
669 }
670
blkdev_open(struct inode * inode,struct file * filp)671 static int blkdev_open(struct inode *inode, struct file *filp)
672 {
673 struct block_device *bdev;
674 blk_mode_t mode;
675 int ret;
676
677 mode = file_to_blk_mode(filp);
678 /* Use the file as the holder. */
679 if (mode & BLK_OPEN_EXCL)
680 filp->private_data = filp;
681 ret = bdev_permission(inode->i_rdev, mode, filp->private_data);
682 if (ret)
683 return ret;
684
685 bdev = blkdev_get_no_open(inode->i_rdev, true);
686 if (!bdev)
687 return -ENXIO;
688
689 if (bdev_can_atomic_write(bdev))
690 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;
691 if (blk_get_integrity(bdev->bd_disk))
692 filp->f_mode |= FMODE_HAS_METADATA;
693
694 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp);
695 if (ret)
696 blkdev_put_no_open(bdev);
697 return ret;
698 }
699
blkdev_release(struct inode * inode,struct file * filp)700 static int blkdev_release(struct inode *inode, struct file *filp)
701 {
702 bdev_release(filp);
703 return 0;
704 }
705
706 static ssize_t
blkdev_direct_write(struct kiocb * iocb,struct iov_iter * from)707 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
708 {
709 size_t count = iov_iter_count(from);
710 ssize_t written;
711
712 written = kiocb_invalidate_pages(iocb, count);
713 if (written) {
714 if (written == -EBUSY)
715 return 0;
716 return written;
717 }
718
719 written = blkdev_direct_IO(iocb, from);
720 if (written > 0) {
721 kiocb_invalidate_post_direct_write(iocb, count);
722 iocb->ki_pos += written;
723 count -= written;
724 }
725 if (written != -EIOCBQUEUED)
726 iov_iter_revert(from, count - iov_iter_count(from));
727 return written;
728 }
729
blkdev_buffered_write(struct kiocb * iocb,struct iov_iter * from)730 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
731 {
732 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL,
733 NULL);
734 }
735
736 /*
737 * Write data to the block device. Only intended for the block device itself
738 * and the raw driver which basically is a fake block device.
739 *
740 * Does not take i_mutex for the write and thus is not for general purpose
741 * use.
742 */
blkdev_write_iter(struct kiocb * iocb,struct iov_iter * from)743 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
744 {
745 struct file *file = iocb->ki_filp;
746 struct inode *bd_inode = bdev_file_inode(file);
747 struct block_device *bdev = I_BDEV(bd_inode);
748 bool atomic = iocb->ki_flags & IOCB_ATOMIC;
749 loff_t size = bdev_nr_bytes(bdev);
750 size_t shorted = 0;
751 ssize_t ret;
752
753 if (bdev_read_only(bdev))
754 return -EPERM;
755
756 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
757 return -ETXTBSY;
758
759 if (!iov_iter_count(from))
760 return 0;
761
762 if (iocb->ki_pos >= size)
763 return -ENOSPC;
764
765 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
766 return -EOPNOTSUPP;
767
768 if (atomic) {
769 ret = generic_atomic_write_valid(iocb, from);
770 if (ret)
771 return ret;
772 }
773
774 size -= iocb->ki_pos;
775 if (iov_iter_count(from) > size) {
776 if (atomic)
777 return -EINVAL;
778 shorted = iov_iter_count(from) - size;
779 iov_iter_truncate(from, size);
780 }
781
782 ret = file_update_time(file);
783 if (ret)
784 return ret;
785
786 if (iocb->ki_flags & IOCB_DIRECT) {
787 ret = blkdev_direct_write(iocb, from);
788 if (ret >= 0 && iov_iter_count(from))
789 ret = direct_write_fallback(iocb, from, ret,
790 blkdev_buffered_write(iocb, from));
791 } else {
792 /*
793 * Take i_rwsem and invalidate_lock to avoid racing with
794 * set_blocksize changing i_blkbits/folio order and punching
795 * out the pagecache.
796 */
797 inode_lock_shared(bd_inode);
798 ret = blkdev_buffered_write(iocb, from);
799 inode_unlock_shared(bd_inode);
800 }
801
802 if (ret > 0)
803 ret = generic_write_sync(iocb, ret);
804 iov_iter_reexpand(from, iov_iter_count(from) + shorted);
805 return ret;
806 }
807
blkdev_read_iter(struct kiocb * iocb,struct iov_iter * to)808 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
809 {
810 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp);
811 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
812 loff_t size = bdev_nr_bytes(bdev);
813 loff_t pos = iocb->ki_pos;
814 size_t shorted = 0;
815 ssize_t ret = 0;
816 size_t count;
817
818 if (unlikely(pos + iov_iter_count(to) > size)) {
819 if (pos >= size)
820 return 0;
821 size -= pos;
822 shorted = iov_iter_count(to) - size;
823 iov_iter_truncate(to, size);
824 }
825
826 count = iov_iter_count(to);
827 if (!count)
828 goto reexpand; /* skip atime */
829
830 if (iocb->ki_flags & IOCB_DIRECT) {
831 ret = kiocb_write_and_wait(iocb, count);
832 if (ret < 0)
833 goto reexpand;
834 file_accessed(iocb->ki_filp);
835
836 ret = blkdev_direct_IO(iocb, to);
837 if (ret > 0) {
838 iocb->ki_pos += ret;
839 count -= ret;
840 }
841 if (ret != -EIOCBQUEUED)
842 iov_iter_revert(to, count - iov_iter_count(to));
843 if (ret < 0 || !count)
844 goto reexpand;
845 }
846
847 /*
848 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize
849 * changing i_blkbits/folio order and punching out the pagecache.
850 */
851 inode_lock_shared(bd_inode);
852 ret = filemap_read(iocb, to, ret);
853 inode_unlock_shared(bd_inode);
854
855 reexpand:
856 if (unlikely(shorted))
857 iov_iter_reexpand(to, iov_iter_count(to) + shorted);
858 return ret;
859 }
860
861 #define BLKDEV_FALLOC_FL_SUPPORTED \
862 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
863 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES)
864
blkdev_fallocate(struct file * file,int mode,loff_t start,loff_t len)865 static long blkdev_fallocate(struct file *file, int mode, loff_t start,
866 loff_t len)
867 {
868 struct inode *inode = bdev_file_inode(file);
869 struct block_device *bdev = I_BDEV(inode);
870 loff_t end = start + len - 1;
871 loff_t isize;
872 unsigned int flags;
873 int error;
874
875 /* Fail if we don't recognize the flags. */
876 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
877 return -EOPNOTSUPP;
878 /*
879 * Don't allow writing zeroes if the device does not enable the
880 * unmap write zeroes operation.
881 */
882 if ((mode & FALLOC_FL_WRITE_ZEROES) &&
883 !bdev_write_zeroes_unmap_sectors(bdev))
884 return -EOPNOTSUPP;
885
886 /* Don't go off the end of the device. */
887 isize = bdev_nr_bytes(bdev);
888 if (start >= isize)
889 return -EINVAL;
890 if (end >= isize) {
891 if (mode & FALLOC_FL_KEEP_SIZE) {
892 len = isize - start;
893 end = start + len - 1;
894 } else
895 return -EINVAL;
896 }
897
898 /*
899 * Don't allow IO that isn't aligned to logical block size.
900 */
901 if ((start | len) & (bdev_logical_block_size(bdev) - 1))
902 return -EINVAL;
903
904 inode_lock(inode);
905 filemap_invalidate_lock(inode->i_mapping);
906
907 switch (mode) {
908 case FALLOC_FL_ZERO_RANGE:
909 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
910 flags = BLKDEV_ZERO_NOUNMAP;
911 break;
912 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
913 flags = BLKDEV_ZERO_NOFALLBACK;
914 break;
915 case FALLOC_FL_WRITE_ZEROES:
916 flags = 0;
917 break;
918 default:
919 error = -EOPNOTSUPP;
920 goto fail;
921 }
922
923 /*
924 * Invalidate the page cache, including dirty pages, for valid
925 * de-allocate mode calls to fallocate().
926 */
927 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
928 if (error)
929 goto fail;
930
931 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
932 len >> SECTOR_SHIFT, GFP_KERNEL, flags);
933 fail:
934 filemap_invalidate_unlock(inode->i_mapping);
935 inode_unlock(inode);
936 return error;
937 }
938
blkdev_mmap_prepare(struct vm_area_desc * desc)939 static int blkdev_mmap_prepare(struct vm_area_desc *desc)
940 {
941 struct file *file = desc->file;
942
943 if (bdev_read_only(I_BDEV(bdev_file_inode(file))))
944 return generic_file_readonly_mmap_prepare(desc);
945
946 return generic_file_mmap_prepare(desc);
947 }
948
949 const struct file_operations def_blk_fops = {
950 .open = blkdev_open,
951 .release = blkdev_release,
952 .llseek = blkdev_llseek,
953 .read_iter = blkdev_read_iter,
954 .write_iter = blkdev_write_iter,
955 .iopoll = iocb_bio_iopoll,
956 .mmap_prepare = blkdev_mmap_prepare,
957 .fsync = blkdev_fsync,
958 .unlocked_ioctl = blkdev_ioctl,
959 #ifdef CONFIG_COMPAT
960 .compat_ioctl = compat_blkdev_ioctl,
961 #endif
962 .splice_read = filemap_splice_read,
963 .splice_write = iter_file_splice_write,
964 .fallocate = blkdev_fallocate,
965 .uring_cmd = blkdev_uring_cmd,
966 .fop_flags = FOP_BUFFER_RASYNC,
967 };
968
blkdev_init(void)969 static __init int blkdev_init(void)
970 {
971 return bioset_init(&blkdev_dio_pool, 4,
972 offsetof(struct blkdev_dio, bio),
973 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
974 }
975 module_init(blkdev_init);
976