projects/linux·blob v6.4 · refs

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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2001 Andrea Arcangeli <[email protected]> SuSE
5 * Copyright (C) 2016 - 2020 Christoph Hellwig
6 */
7
8#include <linux/init.h>
9#include <linux/mm.h>
10#include <linux/slab.h>
11#include <linux/kmod.h>
12#include <linux/major.h>
13#include <linux/device_cgroup.h>
14#include <linux/blkdev.h>
15#include <linux/blk-integrity.h>
16#include <linux/backing-dev.h>
17#include <linux/module.h>
18#include <linux/blkpg.h>
19#include <linux/magic.h>
20#include <linux/buffer_head.h>
21#include <linux/swap.h>
22#include <linux/writeback.h>
23#include <linux/mount.h>
24#include <linux/pseudo_fs.h>
25#include <linux/uio.h>
26#include <linux/namei.h>
27#include <linux/part_stat.h>
28#include <linux/uaccess.h>
29#include <linux/stat.h>
30#include "../fs/internal.h"
31#include "blk.h"
32
33struct bdev_inode {
34 struct block_device bdev;
35 struct inode vfs_inode;
36};
37
38static inline struct bdev_inode *BDEV_I(struct inode *inode)
39{
40 return container_of(inode, struct bdev_inode, vfs_inode);
41}
42
43struct block_device *I_BDEV(struct inode *inode)
44{
45 return &BDEV_I(inode)->bdev;
46}
47EXPORT_SYMBOL(I_BDEV);
48
49static void bdev_write_inode(struct block_device *bdev)
50{
51 struct inode *inode = bdev->bd_inode;
52 int ret;
53
54 spin_lock(&inode->i_lock);
55 while (inode->i_state & I_DIRTY) {
56 spin_unlock(&inode->i_lock);
57 ret = write_inode_now(inode, true);
58 if (ret)
59 pr_warn_ratelimited(
60 "VFS: Dirty inode writeback failed for block device %pg (err=%d).\n",
61 bdev, ret);
62 spin_lock(&inode->i_lock);
63 }
64 spin_unlock(&inode->i_lock);
65}
66
67/* Kill _all_ buffers and pagecache , dirty or not.. */
68static void kill_bdev(struct block_device *bdev)
69{
70 struct address_space *mapping = bdev->bd_inode->i_mapping;
71
72 if (mapping_empty(mapping))
73 return;
74
75 invalidate_bh_lrus();
76 truncate_inode_pages(mapping, 0);
77}
78
79/* Invalidate clean unused buffers and pagecache. */
80void invalidate_bdev(struct block_device *bdev)
81{
82 struct address_space *mapping = bdev->bd_inode->i_mapping;
83
84 if (mapping->nrpages) {
85 invalidate_bh_lrus();
86 lru_add_drain_all(); /* make sure all lru add caches are flushed */
87 invalidate_mapping_pages(mapping, 0, -1);
88 }
89}
90EXPORT_SYMBOL(invalidate_bdev);
91
92/*
93 * Drop all buffers & page cache for given bdev range. This function bails
94 * with error if bdev has other exclusive owner (such as filesystem).
95 */
96int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
97 loff_t lstart, loff_t lend)
98{
99 /*
100 * If we don't hold exclusive handle for the device, upgrade to it
101 * while we discard the buffer cache to avoid discarding buffers
102 * under live filesystem.
103 */
104 if (!(mode & FMODE_EXCL)) {
105 int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
106 if (err)
107 goto invalidate;
108 }
109
110 truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
111 if (!(mode & FMODE_EXCL))
112 bd_abort_claiming(bdev, truncate_bdev_range);
113 return 0;
114
115invalidate:
116 /*
117 * Someone else has handle exclusively open. Try invalidating instead.
118 * The 'end' argument is inclusive so the rounding is safe.
119 */
120 return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
121 lstart >> PAGE_SHIFT,
122 lend >> PAGE_SHIFT);
123}
124
125static void set_init_blocksize(struct block_device *bdev)
126{
127 unsigned int bsize = bdev_logical_block_size(bdev);
128 loff_t size = i_size_read(bdev->bd_inode);
129
130 while (bsize < PAGE_SIZE) {
131 if (size & bsize)
132 break;
133 bsize <<= 1;
134 }
135 bdev->bd_inode->i_blkbits = blksize_bits(bsize);
136}
137
138int set_blocksize(struct block_device *bdev, int size)
139{
140 /* Size must be a power of two, and between 512 and PAGE_SIZE */
141 if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
142 return -EINVAL;
143
144 /* Size cannot be smaller than the size supported by the device */
145 if (size < bdev_logical_block_size(bdev))
146 return -EINVAL;
147
148 /* Don't change the size if it is same as current */
149 if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
150 sync_blockdev(bdev);
151 bdev->bd_inode->i_blkbits = blksize_bits(size);
152 kill_bdev(bdev);
153 }
154 return 0;
155}
156
157EXPORT_SYMBOL(set_blocksize);
158
159int sb_set_blocksize(struct super_block *sb, int size)
160{
161 if (set_blocksize(sb->s_bdev, size))
162 return 0;
163 /* If we get here, we know size is power of two
164 * and it's value is between 512 and PAGE_SIZE */
165 sb->s_blocksize = size;
166 sb->s_blocksize_bits = blksize_bits(size);
167 return sb->s_blocksize;
168}
169
170EXPORT_SYMBOL(sb_set_blocksize);
171
172int sb_min_blocksize(struct super_block *sb, int size)
173{
174 int minsize = bdev_logical_block_size(sb->s_bdev);
175 if (size < minsize)
176 size = minsize;
177 return sb_set_blocksize(sb, size);
178}
179
180EXPORT_SYMBOL(sb_min_blocksize);
181
182int sync_blockdev_nowait(struct block_device *bdev)
183{
184 if (!bdev)
185 return 0;
186 return filemap_flush(bdev->bd_inode->i_mapping);
187}
188EXPORT_SYMBOL_GPL(sync_blockdev_nowait);
189
190/*
191 * Write out and wait upon all the dirty data associated with a block
192 * device via its mapping. Does not take the superblock lock.
193 */
194int sync_blockdev(struct block_device *bdev)
195{
196 if (!bdev)
197 return 0;
198 return filemap_write_and_wait(bdev->bd_inode->i_mapping);
199}
200EXPORT_SYMBOL(sync_blockdev);
201
202int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend)
203{
204 return filemap_write_and_wait_range(bdev->bd_inode->i_mapping,
205 lstart, lend);
206}
207EXPORT_SYMBOL(sync_blockdev_range);
208
209/*
210 * Write out and wait upon all dirty data associated with this
211 * device. Filesystem data as well as the underlying block
212 * device. Takes the superblock lock.
213 */
214int fsync_bdev(struct block_device *bdev)
215{
216 struct super_block *sb = get_super(bdev);
217 if (sb) {
218 int res = sync_filesystem(sb);
219 drop_super(sb);
220 return res;
221 }
222 return sync_blockdev(bdev);
223}
224EXPORT_SYMBOL(fsync_bdev);
225
226/**
227 * freeze_bdev - lock a filesystem and force it into a consistent state
228 * @bdev: blockdevice to lock
229 *
230 * If a superblock is found on this device, we take the s_umount semaphore
231 * on it to make sure nobody unmounts until the snapshot creation is done.
232 * The reference counter (bd_fsfreeze_count) guarantees that only the last
233 * unfreeze process can unfreeze the frozen filesystem actually when multiple
234 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
235 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
236 * actually.
237 */
238int freeze_bdev(struct block_device *bdev)
239{
240 struct super_block *sb;
241 int error = 0;
242
243 mutex_lock(&bdev->bd_fsfreeze_mutex);
244 if (++bdev->bd_fsfreeze_count > 1)
245 goto done;
246
247 sb = get_active_super(bdev);
248 if (!sb)
249 goto sync;
250 if (sb->s_op->freeze_super)
251 error = sb->s_op->freeze_super(sb);
252 else
253 error = freeze_super(sb);
254 deactivate_super(sb);
255
256 if (error) {
257 bdev->bd_fsfreeze_count--;
258 goto done;
259 }
260 bdev->bd_fsfreeze_sb = sb;
261
262sync:
263 sync_blockdev(bdev);
264done:
265 mutex_unlock(&bdev->bd_fsfreeze_mutex);
266 return error;
267}
268EXPORT_SYMBOL(freeze_bdev);
269
270/**
271 * thaw_bdev - unlock filesystem
272 * @bdev: blockdevice to unlock
273 *
274 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
275 */
276int thaw_bdev(struct block_device *bdev)
277{
278 struct super_block *sb;
279 int error = -EINVAL;
280
281 mutex_lock(&bdev->bd_fsfreeze_mutex);
282 if (!bdev->bd_fsfreeze_count)
283 goto out;
284
285 error = 0;
286 if (--bdev->bd_fsfreeze_count > 0)
287 goto out;
288
289 sb = bdev->bd_fsfreeze_sb;
290 if (!sb)
291 goto out;
292
293 if (sb->s_op->thaw_super)
294 error = sb->s_op->thaw_super(sb);
295 else
296 error = thaw_super(sb);
297 if (error)
298 bdev->bd_fsfreeze_count++;
299 else
300 bdev->bd_fsfreeze_sb = NULL;
301out:
302 mutex_unlock(&bdev->bd_fsfreeze_mutex);
303 return error;
304}
305EXPORT_SYMBOL(thaw_bdev);
306
307/*
308 * pseudo-fs
309 */
310
311static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
312static struct kmem_cache * bdev_cachep __read_mostly;
313
314static struct inode *bdev_alloc_inode(struct super_block *sb)
315{
316 struct bdev_inode *ei = alloc_inode_sb(sb, bdev_cachep, GFP_KERNEL);
317
318 if (!ei)
319 return NULL;
320 memset(&ei->bdev, 0, sizeof(ei->bdev));
321 return &ei->vfs_inode;
322}
323
324static void bdev_free_inode(struct inode *inode)
325{
326 struct block_device *bdev = I_BDEV(inode);
327
328 free_percpu(bdev->bd_stats);
329 kfree(bdev->bd_meta_info);
330
331 if (!bdev_is_partition(bdev)) {
332 if (bdev->bd_disk && bdev->bd_disk->bdi)
333 bdi_put(bdev->bd_disk->bdi);
334 kfree(bdev->bd_disk);
335 }
336
337 if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
338 blk_free_ext_minor(MINOR(bdev->bd_dev));
339
340 kmem_cache_free(bdev_cachep, BDEV_I(inode));
341}
342
343static void init_once(void *data)
344{
345 struct bdev_inode *ei = data;
346
347 inode_init_once(&ei->vfs_inode);
348}
349
350static void bdev_evict_inode(struct inode *inode)
351{
352 truncate_inode_pages_final(&inode->i_data);
353 invalidate_inode_buffers(inode); /* is it needed here? */
354 clear_inode(inode);
355}
356
357static const struct super_operations bdev_sops = {
358 .statfs = simple_statfs,
359 .alloc_inode = bdev_alloc_inode,
360 .free_inode = bdev_free_inode,
361 .drop_inode = generic_delete_inode,
362 .evict_inode = bdev_evict_inode,
363};
364
365static int bd_init_fs_context(struct fs_context *fc)
366{
367 struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC);
368 if (!ctx)
369 return -ENOMEM;
370 fc->s_iflags |= SB_I_CGROUPWB;
371 ctx->ops = &bdev_sops;
372 return 0;
373}
374
375static struct file_system_type bd_type = {
376 .name = "bdev",
377 .init_fs_context = bd_init_fs_context,
378 .kill_sb = kill_anon_super,
379};
380
381struct super_block *blockdev_superblock __read_mostly;
382EXPORT_SYMBOL_GPL(blockdev_superblock);
383
384void __init bdev_cache_init(void)
385{
386 int err;
387 static struct vfsmount *bd_mnt;
388
389 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
390 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
391 SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC),
392 init_once);
393 err = register_filesystem(&bd_type);
394 if (err)
395 panic("Cannot register bdev pseudo-fs");
396 bd_mnt = kern_mount(&bd_type);
397 if (IS_ERR(bd_mnt))
398 panic("Cannot create bdev pseudo-fs");
399 blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
400}
401
402struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
403{
404 struct block_device *bdev;
405 struct inode *inode;
406
407 inode = new_inode(blockdev_superblock);
408 if (!inode)
409 return NULL;
410 inode->i_mode = S_IFBLK;
411 inode->i_rdev = 0;
412 inode->i_data.a_ops = &def_blk_aops;
413 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
414
415 bdev = I_BDEV(inode);
416 mutex_init(&bdev->bd_fsfreeze_mutex);
417 spin_lock_init(&bdev->bd_size_lock);
418 bdev->bd_partno = partno;
419 bdev->bd_inode = inode;
420 bdev->bd_queue = disk->queue;
421 if (partno)
422 bdev->bd_has_submit_bio = disk->part0->bd_has_submit_bio;
423 else
424 bdev->bd_has_submit_bio = false;
425 bdev->bd_stats = alloc_percpu(struct disk_stats);
426 if (!bdev->bd_stats) {
427 iput(inode);
428 return NULL;
429 }
430 bdev->bd_disk = disk;
431 return bdev;
432}
433
434void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
435{
436 spin_lock(&bdev->bd_size_lock);
437 i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
438 bdev->bd_nr_sectors = sectors;
439 spin_unlock(&bdev->bd_size_lock);
440}
441
442void bdev_add(struct block_device *bdev, dev_t dev)
443{
444 bdev->bd_dev = dev;
445 bdev->bd_inode->i_rdev = dev;
446 bdev->bd_inode->i_ino = dev;
447 insert_inode_hash(bdev->bd_inode);
448}
449
450long nr_blockdev_pages(void)
451{
452 struct inode *inode;
453 long ret = 0;
454
455 spin_lock(&blockdev_superblock->s_inode_list_lock);
456 list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list)
457 ret += inode->i_mapping->nrpages;
458 spin_unlock(&blockdev_superblock->s_inode_list_lock);
459
460 return ret;
461}
462
463/**
464 * bd_may_claim - test whether a block device can be claimed
465 * @bdev: block device of interest
466 * @whole: whole block device containing @bdev, may equal @bdev
467 * @holder: holder trying to claim @bdev
468 *
469 * Test whether @bdev can be claimed by @holder.
470 *
471 * CONTEXT:
472 * spin_lock(&bdev_lock).
473 *
474 * RETURNS:
475 * %true if @bdev can be claimed, %false otherwise.
476 */
477static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
478 void *holder)
479{
480 if (bdev->bd_holder == holder)
481 return true; /* already a holder */
482 else if (bdev->bd_holder != NULL)
483 return false; /* held by someone else */
484 else if (whole == bdev)
485 return true; /* is a whole device which isn't held */
486
487 else if (whole->bd_holder == bd_may_claim)
488 return true; /* is a partition of a device that is being partitioned */
489 else if (whole->bd_holder != NULL)
490 return false; /* is a partition of a held device */
491 else
492 return true; /* is a partition of an un-held device */
493}
494
495/**
496 * bd_prepare_to_claim - claim a block device
497 * @bdev: block device of interest
498 * @holder: holder trying to claim @bdev
499 *
500 * Claim @bdev. This function fails if @bdev is already claimed by another
501 * holder and waits if another claiming is in progress. return, the caller
502 * has ownership of bd_claiming and bd_holder[s].
503 *
504 * RETURNS:
505 * 0 if @bdev can be claimed, -EBUSY otherwise.
506 */
507int bd_prepare_to_claim(struct block_device *bdev, void *holder)
508{
509 struct block_device *whole = bdev_whole(bdev);
510
511 if (WARN_ON_ONCE(!holder))
512 return -EINVAL;
513retry:
514 spin_lock(&bdev_lock);
515 /* if someone else claimed, fail */
516 if (!bd_may_claim(bdev, whole, holder)) {
517 spin_unlock(&bdev_lock);
518 return -EBUSY;
519 }
520
521 /* if claiming is already in progress, wait for it to finish */
522 if (whole->bd_claiming) {
523 wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
524 DEFINE_WAIT(wait);
525
526 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
527 spin_unlock(&bdev_lock);
528 schedule();
529 finish_wait(wq, &wait);
530 goto retry;
531 }
532
533 /* yay, all mine */
534 whole->bd_claiming = holder;
535 spin_unlock(&bdev_lock);
536 return 0;
537}
538EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
539
540static void bd_clear_claiming(struct block_device *whole, void *holder)
541{
542 lockdep_assert_held(&bdev_lock);
543 /* tell others that we're done */
544 BUG_ON(whole->bd_claiming != holder);
545 whole->bd_claiming = NULL;
546 wake_up_bit(&whole->bd_claiming, 0);
547}
548
549/**
550 * bd_finish_claiming - finish claiming of a block device
551 * @bdev: block device of interest
552 * @holder: holder that has claimed @bdev
553 *
554 * Finish exclusive open of a block device. Mark the device as exlusively
555 * open by the holder and wake up all waiters for exclusive open to finish.
556 */
557static void bd_finish_claiming(struct block_device *bdev, void *holder)
558{
559 struct block_device *whole = bdev_whole(bdev);
560
561 spin_lock(&bdev_lock);
562 BUG_ON(!bd_may_claim(bdev, whole, holder));
563 /*
564 * Note that for a whole device bd_holders will be incremented twice,
565 * and bd_holder will be set to bd_may_claim before being set to holder
566 */
567 whole->bd_holders++;
568 whole->bd_holder = bd_may_claim;
569 bdev->bd_holders++;
570 bdev->bd_holder = holder;
571 bd_clear_claiming(whole, holder);
572 spin_unlock(&bdev_lock);
573}
574
575/**
576 * bd_abort_claiming - abort claiming of a block device
577 * @bdev: block device of interest
578 * @holder: holder that has claimed @bdev
579 *
580 * Abort claiming of a block device when the exclusive open failed. This can be
581 * also used when exclusive open is not actually desired and we just needed
582 * to block other exclusive openers for a while.
583 */
584void bd_abort_claiming(struct block_device *bdev, void *holder)
585{
586 spin_lock(&bdev_lock);
587 bd_clear_claiming(bdev_whole(bdev), holder);
588 spin_unlock(&bdev_lock);
589}
590EXPORT_SYMBOL(bd_abort_claiming);
591
592static void blkdev_flush_mapping(struct block_device *bdev)
593{
594 WARN_ON_ONCE(bdev->bd_holders);
595 sync_blockdev(bdev);
596 kill_bdev(bdev);
597 bdev_write_inode(bdev);
598}
599
600static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
601{
602 struct gendisk *disk = bdev->bd_disk;
603 int ret;
604
605 if (disk->fops->open) {
606 ret = disk->fops->open(bdev, mode);
607 if (ret) {
608 /* avoid ghost partitions on a removed medium */
609 if (ret == -ENOMEDIUM &&
610 test_bit(GD_NEED_PART_SCAN, &disk->state))
611 bdev_disk_changed(disk, true);
612 return ret;
613 }
614 }
615
616 if (!atomic_read(&bdev->bd_openers))
617 set_init_blocksize(bdev);
618 if (test_bit(GD_NEED_PART_SCAN, &disk->state))
619 bdev_disk_changed(disk, false);
620 atomic_inc(&bdev->bd_openers);
621 return 0;
622}
623
624static void blkdev_put_whole(struct block_device *bdev, fmode_t mode)
625{
626 if (atomic_dec_and_test(&bdev->bd_openers))
627 blkdev_flush_mapping(bdev);
628 if (bdev->bd_disk->fops->release)
629 bdev->bd_disk->fops->release(bdev->bd_disk, mode);
630}
631
632static int blkdev_get_part(struct block_device *part, fmode_t mode)
633{
634 struct gendisk *disk = part->bd_disk;
635 int ret;
636
637 if (atomic_read(&part->bd_openers))
638 goto done;
639
640 ret = blkdev_get_whole(bdev_whole(part), mode);
641 if (ret)
642 return ret;
643
644 ret = -ENXIO;
645 if (!bdev_nr_sectors(part))
646 goto out_blkdev_put;
647
648 disk->open_partitions++;
649 set_init_blocksize(part);
650done:
651 atomic_inc(&part->bd_openers);
652 return 0;
653
654out_blkdev_put:
655 blkdev_put_whole(bdev_whole(part), mode);
656 return ret;
657}
658
659static void blkdev_put_part(struct block_device *part, fmode_t mode)
660{
661 struct block_device *whole = bdev_whole(part);
662
663 if (!atomic_dec_and_test(&part->bd_openers))
664 return;
665 blkdev_flush_mapping(part);
666 whole->bd_disk->open_partitions--;
667 blkdev_put_whole(whole, mode);
668}
669
670struct block_device *blkdev_get_no_open(dev_t dev)
671{
672 struct block_device *bdev;
673 struct inode *inode;
674
675 inode = ilookup(blockdev_superblock, dev);
676 if (!inode && IS_ENABLED(CONFIG_BLOCK_LEGACY_AUTOLOAD)) {
677 blk_request_module(dev);
678 inode = ilookup(blockdev_superblock, dev);
679 if (inode)
680 pr_warn_ratelimited(
681"block device autoloading is deprecated and will be removed.\n");
682 }
683 if (!inode)
684 return NULL;
685
686 /* switch from the inode reference to a device mode one: */
687 bdev = &BDEV_I(inode)->bdev;
688 if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
689 bdev = NULL;
690 iput(inode);
691 return bdev;
692}
693
694void blkdev_put_no_open(struct block_device *bdev)
695{
696 put_device(&bdev->bd_device);
697}
698
699/**
700 * blkdev_get_by_dev - open a block device by device number
701 * @dev: device number of block device to open
702 * @mode: FMODE_* mask
703 * @holder: exclusive holder identifier
704 *
705 * Open the block device described by device number @dev. If @mode includes
706 * %FMODE_EXCL, the block device is opened with exclusive access. Specifying
707 * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for
708 * the same @holder.
709 *
710 * Use this interface ONLY if you really do not have anything better - i.e. when
711 * you are behind a truly sucky interface and all you are given is a device
712 * number. Everything else should use blkdev_get_by_path().
713 *
714 * CONTEXT:
715 * Might sleep.
716 *
717 * RETURNS:
718 * Reference to the block_device on success, ERR_PTR(-errno) on failure.
719 */
720struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
721{
722 bool unblock_events = true;
723 struct block_device *bdev;
724 struct gendisk *disk;
725 int ret;
726
727 ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
728 MAJOR(dev), MINOR(dev),
729 ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
730 ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
731 if (ret)
732 return ERR_PTR(ret);
733
734 bdev = blkdev_get_no_open(dev);
735 if (!bdev)
736 return ERR_PTR(-ENXIO);
737 disk = bdev->bd_disk;
738
739 if (mode & FMODE_EXCL) {
740 ret = bd_prepare_to_claim(bdev, holder);
741 if (ret)
742 goto put_blkdev;
743 }
744
745 disk_block_events(disk);
746
747 mutex_lock(&disk->open_mutex);
748 ret = -ENXIO;
749 if (!disk_live(disk))
750 goto abort_claiming;
751 if (!try_module_get(disk->fops->owner))
752 goto abort_claiming;
753 if (bdev_is_partition(bdev))
754 ret = blkdev_get_part(bdev, mode);
755 else
756 ret = blkdev_get_whole(bdev, mode);
757 if (ret)
758 goto put_module;
759 if (mode & FMODE_EXCL) {
760 bd_finish_claiming(bdev, holder);
761
762 /*
763 * Block event polling for write claims if requested. Any write
764 * holder makes the write_holder state stick until all are
765 * released. This is good enough and tracking individual
766 * writeable reference is too fragile given the way @mode is
767 * used in blkdev_get/put().
768 */
769 if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
770 (disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) {
771 bdev->bd_write_holder = true;
772 unblock_events = false;
773 }
774 }
775 mutex_unlock(&disk->open_mutex);
776
777 if (unblock_events)
778 disk_unblock_events(disk);
779 return bdev;
780put_module:
781 module_put(disk->fops->owner);
782abort_claiming:
783 if (mode & FMODE_EXCL)
784 bd_abort_claiming(bdev, holder);
785 mutex_unlock(&disk->open_mutex);
786 disk_unblock_events(disk);
787put_blkdev:
788 blkdev_put_no_open(bdev);
789 return ERR_PTR(ret);
790}
791EXPORT_SYMBOL(blkdev_get_by_dev);
792
793/**
794 * blkdev_get_by_path - open a block device by name
795 * @path: path to the block device to open
796 * @mode: FMODE_* mask
797 * @holder: exclusive holder identifier
798 *
799 * Open the block device described by the device file at @path. If @mode
800 * includes %FMODE_EXCL, the block device is opened with exclusive access.
801 * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may
802 * nest for the same @holder.
803 *
804 * CONTEXT:
805 * Might sleep.
806 *
807 * RETURNS:
808 * Reference to the block_device on success, ERR_PTR(-errno) on failure.
809 */
810struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
811 void *holder)
812{
813 struct block_device *bdev;
814 dev_t dev;
815 int error;
816
817 error = lookup_bdev(path, &dev);
818 if (error)
819 return ERR_PTR(error);
820
821 bdev = blkdev_get_by_dev(dev, mode, holder);
822 if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
823 blkdev_put(bdev, mode);
824 return ERR_PTR(-EACCES);
825 }
826
827 return bdev;
828}
829EXPORT_SYMBOL(blkdev_get_by_path);
830
831void blkdev_put(struct block_device *bdev, fmode_t mode)
832{
833 struct gendisk *disk = bdev->bd_disk;
834
835 /*
836 * Sync early if it looks like we're the last one. If someone else
837 * opens the block device between now and the decrement of bd_openers
838 * then we did a sync that we didn't need to, but that's not the end
839 * of the world and we want to avoid long (could be several minute)
840 * syncs while holding the mutex.
841 */
842 if (atomic_read(&bdev->bd_openers) == 1)
843 sync_blockdev(bdev);
844
845 mutex_lock(&disk->open_mutex);
846 if (mode & FMODE_EXCL) {
847 struct block_device *whole = bdev_whole(bdev);
848 bool bdev_free;
849
850 /*
851 * Release a claim on the device. The holder fields
852 * are protected with bdev_lock. open_mutex is to
853 * synchronize disk_holder unlinking.
854 */
855 spin_lock(&bdev_lock);
856
857 WARN_ON_ONCE(--bdev->bd_holders < 0);
858 WARN_ON_ONCE(--whole->bd_holders < 0);
859
860 if ((bdev_free = !bdev->bd_holders))
861 bdev->bd_holder = NULL;
862 if (!whole->bd_holders)
863 whole->bd_holder = NULL;
864
865 spin_unlock(&bdev_lock);
866
867 /*
868 * If this was the last claim, remove holder link and
869 * unblock evpoll if it was a write holder.
870 */
871 if (bdev_free && bdev->bd_write_holder) {
872 disk_unblock_events(disk);
873 bdev->bd_write_holder = false;
874 }
875 }
876
877 /*
878 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
879 * event. This is to ensure detection of media removal commanded
880 * from userland - e.g. eject(1).
881 */
882 disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
883
884 if (bdev_is_partition(bdev))
885 blkdev_put_part(bdev, mode);
886 else
887 blkdev_put_whole(bdev, mode);
888 mutex_unlock(&disk->open_mutex);
889
890 module_put(disk->fops->owner);
891 blkdev_put_no_open(bdev);
892}
893EXPORT_SYMBOL(blkdev_put);
894
895/**
896 * lookup_bdev() - Look up a struct block_device by name.
897 * @pathname: Name of the block device in the filesystem.
898 * @dev: Pointer to the block device's dev_t, if found.
899 *
900 * Lookup the block device's dev_t at @pathname in the current
901 * namespace if possible and return it in @dev.
902 *
903 * Context: May sleep.
904 * Return: 0 if succeeded, negative errno otherwise.
905 */
906int lookup_bdev(const char *pathname, dev_t *dev)
907{
908 struct inode *inode;
909 struct path path;
910 int error;
911
912 if (!pathname || !*pathname)
913 return -EINVAL;
914
915 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
916 if (error)
917 return error;
918
919 inode = d_backing_inode(path.dentry);
920 error = -ENOTBLK;
921 if (!S_ISBLK(inode->i_mode))
922 goto out_path_put;
923 error = -EACCES;
924 if (!may_open_dev(&path))
925 goto out_path_put;
926
927 *dev = inode->i_rdev;
928 error = 0;
929out_path_put:
930 path_put(&path);
931 return error;
932}
933EXPORT_SYMBOL(lookup_bdev);
934
935int __invalidate_device(struct block_device *bdev, bool kill_dirty)
936{
937 struct super_block *sb = get_super(bdev);
938 int res = 0;
939
940 if (sb) {
941 /*
942 * no need to lock the super, get_super holds the
943 * read mutex so the filesystem cannot go away
944 * under us (->put_super runs with the write lock
945 * hold).
946 */
947 shrink_dcache_sb(sb);
948 res = invalidate_inodes(sb, kill_dirty);
949 drop_super(sb);
950 }
951 invalidate_bdev(bdev);
952 return res;
953}
954EXPORT_SYMBOL(__invalidate_device);
955
956void sync_bdevs(bool wait)
957{
958 struct inode *inode, *old_inode = NULL;
959
960 spin_lock(&blockdev_superblock->s_inode_list_lock);
961 list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
962 struct address_space *mapping = inode->i_mapping;
963 struct block_device *bdev;
964
965 spin_lock(&inode->i_lock);
966 if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
967 mapping->nrpages == 0) {
968 spin_unlock(&inode->i_lock);
969 continue;
970 }
971 __iget(inode);
972 spin_unlock(&inode->i_lock);
973 spin_unlock(&blockdev_superblock->s_inode_list_lock);
974 /*
975 * We hold a reference to 'inode' so it couldn't have been
976 * removed from s_inodes list while we dropped the
977 * s_inode_list_lock We cannot iput the inode now as we can
978 * be holding the last reference and we cannot iput it under
979 * s_inode_list_lock. So we keep the reference and iput it
980 * later.
981 */
982 iput(old_inode);
983 old_inode = inode;
984 bdev = I_BDEV(inode);
985
986 mutex_lock(&bdev->bd_disk->open_mutex);
987 if (!atomic_read(&bdev->bd_openers)) {
988 ; /* skip */
989 } else if (wait) {
990 /*
991 * We keep the error status of individual mapping so
992 * that applications can catch the writeback error using
993 * fsync(2). See filemap_fdatawait_keep_errors() for
994 * details.
995 */
996 filemap_fdatawait_keep_errors(inode->i_mapping);
997 } else {
998 filemap_fdatawrite(inode->i_mapping);
999 }
1000 mutex_unlock(&bdev->bd_disk->open_mutex);
1001
1002 spin_lock(&blockdev_superblock->s_inode_list_lock);
1003 }
1004 spin_unlock(&blockdev_superblock->s_inode_list_lock);
1005 iput(old_inode);
1006}
1007
1008/*
1009 * Handle STATX_DIOALIGN for block devices.
1010 *
1011 * Note that the inode passed to this is the inode of a block device node file,
1012 * not the block device's internal inode. Therefore it is *not* valid to use
1013 * I_BDEV() here; the block device has to be looked up by i_rdev instead.
1014 */
1015void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
1016{
1017 struct block_device *bdev;
1018
1019 bdev = blkdev_get_no_open(inode->i_rdev);
1020 if (!bdev)
1021 return;
1022
1023 stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
1024 stat->dio_offset_align = bdev_logical_block_size(bdev);
1025 stat->result_mask |= STATX_DIOALIGN;
1026
1027 blkdev_put_no_open(bdev);
1028}