Line data Source code
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 :
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 :
33 : struct bdev_inode {
34 : struct block_device bdev;
35 : struct inode vfs_inode;
36 : };
37 :
38 : static inline struct bdev_inode *BDEV_I(struct inode *inode)
39 : {
40 0 : return container_of(inode, struct bdev_inode, vfs_inode);
41 : }
42 :
43 0 : struct block_device *I_BDEV(struct inode *inode)
44 : {
45 0 : return &BDEV_I(inode)->bdev;
46 : }
47 : EXPORT_SYMBOL(I_BDEV);
48 :
49 0 : static void bdev_write_inode(struct block_device *bdev)
50 : {
51 0 : struct inode *inode = bdev->bd_inode;
52 : int ret;
53 :
54 0 : spin_lock(&inode->i_lock);
55 0 : while (inode->i_state & I_DIRTY) {
56 0 : spin_unlock(&inode->i_lock);
57 0 : ret = write_inode_now(inode, true);
58 0 : if (ret)
59 0 : pr_warn_ratelimited(
60 : "VFS: Dirty inode writeback failed for block device %pg (err=%d).\n",
61 : bdev, ret);
62 0 : spin_lock(&inode->i_lock);
63 : }
64 0 : spin_unlock(&inode->i_lock);
65 0 : }
66 :
67 : /* Kill _all_ buffers and pagecache , dirty or not.. */
68 0 : static void kill_bdev(struct block_device *bdev)
69 : {
70 0 : struct address_space *mapping = bdev->bd_inode->i_mapping;
71 :
72 0 : if (mapping_empty(mapping))
73 : return;
74 :
75 0 : invalidate_bh_lrus();
76 0 : truncate_inode_pages(mapping, 0);
77 : }
78 :
79 : /* Invalidate clean unused buffers and pagecache. */
80 0 : void invalidate_bdev(struct block_device *bdev)
81 : {
82 0 : struct address_space *mapping = bdev->bd_inode->i_mapping;
83 :
84 0 : if (mapping->nrpages) {
85 0 : invalidate_bh_lrus();
86 0 : lru_add_drain_all(); /* make sure all lru add caches are flushed */
87 0 : invalidate_mapping_pages(mapping, 0, -1);
88 : }
89 0 : }
90 : EXPORT_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 : */
96 0 : int 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 0 : if (!(mode & FMODE_EXCL)) {
105 0 : int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
106 0 : if (err)
107 : goto invalidate;
108 : }
109 :
110 0 : truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
111 0 : if (!(mode & FMODE_EXCL))
112 : bd_abort_claiming(bdev, truncate_bdev_range);
113 : return 0;
114 :
115 : invalidate:
116 : /*
117 : * Someone else has handle exclusively open. Try invalidating instead.
118 : * The 'end' argument is inclusive so the rounding is safe.
119 : */
120 0 : return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
121 0 : lstart >> PAGE_SHIFT,
122 0 : lend >> PAGE_SHIFT);
123 : }
124 :
125 0 : static void set_init_blocksize(struct block_device *bdev)
126 : {
127 0 : unsigned int bsize = bdev_logical_block_size(bdev);
128 0 : loff_t size = i_size_read(bdev->bd_inode);
129 :
130 0 : while (bsize < PAGE_SIZE) {
131 0 : if (size & bsize)
132 : break;
133 0 : bsize <<= 1;
134 : }
135 0 : bdev->bd_inode->i_blkbits = blksize_bits(bsize);
136 0 : }
137 :
138 0 : int set_blocksize(struct block_device *bdev, int size)
139 : {
140 : /* Size must be a power of two, and between 512 and PAGE_SIZE */
141 0 : 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 0 : if (size < bdev_logical_block_size(bdev))
146 : return -EINVAL;
147 :
148 : /* Don't change the size if it is same as current */
149 0 : if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
150 0 : sync_blockdev(bdev);
151 0 : bdev->bd_inode->i_blkbits = blksize_bits(size);
152 0 : kill_bdev(bdev);
153 : }
154 : return 0;
155 : }
156 :
157 : EXPORT_SYMBOL(set_blocksize);
158 :
159 0 : int sb_set_blocksize(struct super_block *sb, int size)
160 : {
161 0 : 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 0 : sb->s_blocksize = size;
166 0 : sb->s_blocksize_bits = blksize_bits(size);
167 0 : return sb->s_blocksize;
168 : }
169 :
170 : EXPORT_SYMBOL(sb_set_blocksize);
171 :
172 0 : int sb_min_blocksize(struct super_block *sb, int size)
173 : {
174 0 : int minsize = bdev_logical_block_size(sb->s_bdev);
175 0 : if (size < minsize)
176 0 : size = minsize;
177 0 : return sb_set_blocksize(sb, size);
178 : }
179 :
180 : EXPORT_SYMBOL(sb_min_blocksize);
181 :
182 22 : int sync_blockdev_nowait(struct block_device *bdev)
183 : {
184 22 : if (!bdev)
185 : return 0;
186 0 : return filemap_flush(bdev->bd_inode->i_mapping);
187 : }
188 : EXPORT_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 : */
194 22 : int sync_blockdev(struct block_device *bdev)
195 : {
196 22 : if (!bdev)
197 : return 0;
198 0 : return filemap_write_and_wait(bdev->bd_inode->i_mapping);
199 : }
200 : EXPORT_SYMBOL(sync_blockdev);
201 :
202 0 : int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend)
203 : {
204 0 : return filemap_write_and_wait_range(bdev->bd_inode->i_mapping,
205 : lstart, lend);
206 : }
207 : EXPORT_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 : */
214 0 : int fsync_bdev(struct block_device *bdev)
215 : {
216 0 : struct super_block *sb = get_super(bdev);
217 0 : if (sb) {
218 0 : int res = sync_filesystem(sb);
219 0 : drop_super(sb);
220 0 : return res;
221 : }
222 : return sync_blockdev(bdev);
223 : }
224 : EXPORT_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 : */
238 0 : int freeze_bdev(struct block_device *bdev)
239 : {
240 : struct super_block *sb;
241 0 : int error = 0;
242 :
243 0 : mutex_lock(&bdev->bd_fsfreeze_mutex);
244 0 : if (++bdev->bd_fsfreeze_count > 1)
245 : goto done;
246 :
247 0 : sb = get_active_super(bdev);
248 0 : if (!sb)
249 : goto sync;
250 0 : if (sb->s_op->freeze_super)
251 0 : error = sb->s_op->freeze_super(sb);
252 : else
253 0 : error = freeze_super(sb);
254 0 : deactivate_super(sb);
255 :
256 0 : if (error) {
257 0 : bdev->bd_fsfreeze_count--;
258 0 : goto done;
259 : }
260 0 : bdev->bd_fsfreeze_sb = sb;
261 :
262 : sync:
263 : sync_blockdev(bdev);
264 : done:
265 0 : mutex_unlock(&bdev->bd_fsfreeze_mutex);
266 0 : return error;
267 : }
268 : EXPORT_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 : */
276 0 : int thaw_bdev(struct block_device *bdev)
277 : {
278 : struct super_block *sb;
279 0 : int error = -EINVAL;
280 :
281 0 : mutex_lock(&bdev->bd_fsfreeze_mutex);
282 0 : if (!bdev->bd_fsfreeze_count)
283 : goto out;
284 :
285 0 : error = 0;
286 0 : if (--bdev->bd_fsfreeze_count > 0)
287 : goto out;
288 :
289 0 : sb = bdev->bd_fsfreeze_sb;
290 0 : if (!sb)
291 : goto out;
292 :
293 0 : if (sb->s_op->thaw_super)
294 0 : error = sb->s_op->thaw_super(sb);
295 : else
296 0 : error = thaw_super(sb);
297 0 : if (error)
298 0 : bdev->bd_fsfreeze_count++;
299 : else
300 0 : bdev->bd_fsfreeze_sb = NULL;
301 : out:
302 0 : mutex_unlock(&bdev->bd_fsfreeze_mutex);
303 0 : return error;
304 : }
305 : EXPORT_SYMBOL(thaw_bdev);
306 :
307 : /*
308 : * pseudo-fs
309 : */
310 :
311 : static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
312 : static struct kmem_cache * bdev_cachep __read_mostly;
313 :
314 1 : static struct inode *bdev_alloc_inode(struct super_block *sb)
315 : {
316 2 : struct bdev_inode *ei = alloc_inode_sb(sb, bdev_cachep, GFP_KERNEL);
317 :
318 1 : if (!ei)
319 : return NULL;
320 1 : memset(&ei->bdev, 0, sizeof(ei->bdev));
321 1 : return &ei->vfs_inode;
322 : }
323 :
324 0 : static void bdev_free_inode(struct inode *inode)
325 : {
326 0 : struct block_device *bdev = I_BDEV(inode);
327 :
328 0 : free_percpu(bdev->bd_stats);
329 0 : kfree(bdev->bd_meta_info);
330 :
331 0 : if (!bdev_is_partition(bdev)) {
332 0 : if (bdev->bd_disk && bdev->bd_disk->bdi)
333 0 : bdi_put(bdev->bd_disk->bdi);
334 0 : kfree(bdev->bd_disk);
335 : }
336 :
337 0 : if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
338 0 : blk_free_ext_minor(MINOR(bdev->bd_dev));
339 :
340 0 : kmem_cache_free(bdev_cachep, BDEV_I(inode));
341 0 : }
342 :
343 11 : static void init_once(void *data)
344 : {
345 11 : struct bdev_inode *ei = data;
346 :
347 11 : inode_init_once(&ei->vfs_inode);
348 11 : }
349 :
350 0 : static void bdev_evict_inode(struct inode *inode)
351 : {
352 0 : truncate_inode_pages_final(&inode->i_data);
353 0 : invalidate_inode_buffers(inode); /* is it needed here? */
354 0 : clear_inode(inode);
355 0 : }
356 :
357 : static 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 :
365 1 : static int bd_init_fs_context(struct fs_context *fc)
366 : {
367 1 : struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC);
368 1 : if (!ctx)
369 : return -ENOMEM;
370 1 : fc->s_iflags |= SB_I_CGROUPWB;
371 1 : ctx->ops = &bdev_sops;
372 1 : return 0;
373 : }
374 :
375 : static 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 :
381 : struct super_block *blockdev_superblock __read_mostly;
382 : EXPORT_SYMBOL_GPL(blockdev_superblock);
383 :
384 1 : void __init bdev_cache_init(void)
385 : {
386 : int err;
387 : static struct vfsmount *bd_mnt;
388 :
389 1 : 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 1 : err = register_filesystem(&bd_type);
394 1 : if (err)
395 0 : panic("Cannot register bdev pseudo-fs");
396 1 : bd_mnt = kern_mount(&bd_type);
397 2 : if (IS_ERR(bd_mnt))
398 0 : panic("Cannot create bdev pseudo-fs");
399 1 : blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
400 1 : }
401 :
402 0 : struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
403 : {
404 : struct block_device *bdev;
405 : struct inode *inode;
406 :
407 0 : inode = new_inode(blockdev_superblock);
408 0 : if (!inode)
409 : return NULL;
410 0 : inode->i_mode = S_IFBLK;
411 0 : inode->i_rdev = 0;
412 0 : inode->i_data.a_ops = &def_blk_aops;
413 0 : mapping_set_gfp_mask(&inode->i_data, GFP_USER);
414 :
415 0 : bdev = I_BDEV(inode);
416 0 : mutex_init(&bdev->bd_fsfreeze_mutex);
417 0 : spin_lock_init(&bdev->bd_size_lock);
418 0 : bdev->bd_partno = partno;
419 0 : bdev->bd_inode = inode;
420 0 : bdev->bd_queue = disk->queue;
421 0 : if (partno)
422 0 : bdev->bd_has_submit_bio = disk->part0->bd_has_submit_bio;
423 : else
424 0 : bdev->bd_has_submit_bio = false;
425 0 : bdev->bd_stats = alloc_percpu(struct disk_stats);
426 0 : if (!bdev->bd_stats) {
427 0 : iput(inode);
428 0 : return NULL;
429 : }
430 0 : bdev->bd_disk = disk;
431 0 : return bdev;
432 : }
433 :
434 0 : void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
435 : {
436 0 : spin_lock(&bdev->bd_size_lock);
437 0 : i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
438 0 : bdev->bd_nr_sectors = sectors;
439 0 : spin_unlock(&bdev->bd_size_lock);
440 0 : }
441 :
442 0 : void bdev_add(struct block_device *bdev, dev_t dev)
443 : {
444 0 : bdev->bd_dev = dev;
445 0 : bdev->bd_inode->i_rdev = dev;
446 0 : bdev->bd_inode->i_ino = dev;
447 0 : insert_inode_hash(bdev->bd_inode);
448 0 : }
449 :
450 2 : long nr_blockdev_pages(void)
451 : {
452 : struct inode *inode;
453 2 : long ret = 0;
454 :
455 4 : spin_lock(&blockdev_superblock->s_inode_list_lock);
456 4 : list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list)
457 2 : ret += inode->i_mapping->nrpages;
458 4 : spin_unlock(&blockdev_superblock->s_inode_list_lock);
459 :
460 2 : 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 : */
477 0 : static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
478 : void *holder)
479 : {
480 0 : if (bdev->bd_holder == holder)
481 : return true; /* already a holder */
482 0 : else if (bdev->bd_holder != NULL)
483 : return false; /* held by someone else */
484 0 : else if (whole == bdev)
485 : return true; /* is a whole device which isn't held */
486 :
487 0 : else if (whole->bd_holder == bd_may_claim)
488 : return true; /* is a partition of a device that is being partitioned */
489 0 : else if (whole->bd_holder != NULL)
490 : return false; /* is a partition of a held device */
491 : else
492 0 : 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 : */
507 0 : int bd_prepare_to_claim(struct block_device *bdev, void *holder)
508 : {
509 0 : struct block_device *whole = bdev_whole(bdev);
510 :
511 0 : if (WARN_ON_ONCE(!holder))
512 : return -EINVAL;
513 : retry:
514 0 : spin_lock(&bdev_lock);
515 : /* if someone else claimed, fail */
516 0 : if (!bd_may_claim(bdev, whole, holder)) {
517 0 : spin_unlock(&bdev_lock);
518 0 : return -EBUSY;
519 : }
520 :
521 : /* if claiming is already in progress, wait for it to finish */
522 0 : if (whole->bd_claiming) {
523 0 : wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
524 0 : DEFINE_WAIT(wait);
525 :
526 0 : prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
527 0 : spin_unlock(&bdev_lock);
528 0 : schedule();
529 0 : finish_wait(wq, &wait);
530 : goto retry;
531 : }
532 :
533 : /* yay, all mine */
534 0 : whole->bd_claiming = holder;
535 0 : spin_unlock(&bdev_lock);
536 0 : return 0;
537 : }
538 : EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
539 :
540 0 : static 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 0 : BUG_ON(whole->bd_claiming != holder);
545 0 : whole->bd_claiming = NULL;
546 0 : wake_up_bit(&whole->bd_claiming, 0);
547 0 : }
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 : */
557 0 : static void bd_finish_claiming(struct block_device *bdev, void *holder)
558 : {
559 0 : struct block_device *whole = bdev_whole(bdev);
560 :
561 0 : spin_lock(&bdev_lock);
562 0 : 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 0 : whole->bd_holders++;
568 0 : whole->bd_holder = bd_may_claim;
569 0 : bdev->bd_holders++;
570 0 : bdev->bd_holder = holder;
571 0 : bd_clear_claiming(whole, holder);
572 0 : spin_unlock(&bdev_lock);
573 0 : }
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 : */
584 0 : void bd_abort_claiming(struct block_device *bdev, void *holder)
585 : {
586 0 : spin_lock(&bdev_lock);
587 0 : bd_clear_claiming(bdev_whole(bdev), holder);
588 0 : spin_unlock(&bdev_lock);
589 0 : }
590 : EXPORT_SYMBOL(bd_abort_claiming);
591 :
592 0 : static void blkdev_flush_mapping(struct block_device *bdev)
593 : {
594 0 : WARN_ON_ONCE(bdev->bd_holders);
595 0 : sync_blockdev(bdev);
596 0 : kill_bdev(bdev);
597 0 : bdev_write_inode(bdev);
598 0 : }
599 :
600 0 : static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
601 : {
602 0 : struct gendisk *disk = bdev->bd_disk;
603 : int ret;
604 :
605 0 : if (disk->fops->open) {
606 0 : ret = disk->fops->open(bdev, mode);
607 0 : if (ret) {
608 : /* avoid ghost partitions on a removed medium */
609 0 : if (ret == -ENOMEDIUM &&
610 0 : test_bit(GD_NEED_PART_SCAN, &disk->state))
611 0 : bdev_disk_changed(disk, true);
612 : return ret;
613 : }
614 : }
615 :
616 0 : if (!atomic_read(&bdev->bd_openers))
617 0 : set_init_blocksize(bdev);
618 0 : if (test_bit(GD_NEED_PART_SCAN, &disk->state))
619 0 : bdev_disk_changed(disk, false);
620 0 : atomic_inc(&bdev->bd_openers);
621 0 : return 0;
622 : }
623 :
624 0 : static void blkdev_put_whole(struct block_device *bdev, fmode_t mode)
625 : {
626 0 : if (atomic_dec_and_test(&bdev->bd_openers))
627 0 : blkdev_flush_mapping(bdev);
628 0 : if (bdev->bd_disk->fops->release)
629 0 : bdev->bd_disk->fops->release(bdev->bd_disk, mode);
630 0 : }
631 :
632 0 : static int blkdev_get_part(struct block_device *part, fmode_t mode)
633 : {
634 0 : struct gendisk *disk = part->bd_disk;
635 : int ret;
636 :
637 0 : if (atomic_read(&part->bd_openers))
638 : goto done;
639 :
640 0 : ret = blkdev_get_whole(bdev_whole(part), mode);
641 0 : if (ret)
642 : return ret;
643 :
644 0 : ret = -ENXIO;
645 0 : if (!bdev_nr_sectors(part))
646 : goto out_blkdev_put;
647 :
648 0 : disk->open_partitions++;
649 0 : set_init_blocksize(part);
650 : done:
651 0 : atomic_inc(&part->bd_openers);
652 0 : return 0;
653 :
654 : out_blkdev_put:
655 0 : blkdev_put_whole(bdev_whole(part), mode);
656 0 : return ret;
657 : }
658 :
659 0 : static void blkdev_put_part(struct block_device *part, fmode_t mode)
660 : {
661 0 : struct block_device *whole = bdev_whole(part);
662 :
663 0 : if (!atomic_dec_and_test(&part->bd_openers))
664 : return;
665 0 : blkdev_flush_mapping(part);
666 0 : whole->bd_disk->open_partitions--;
667 0 : blkdev_put_whole(whole, mode);
668 : }
669 :
670 0 : struct block_device *blkdev_get_no_open(dev_t dev)
671 : {
672 : struct block_device *bdev;
673 : struct inode *inode;
674 :
675 0 : inode = ilookup(blockdev_superblock, dev);
676 0 : if (!inode && IS_ENABLED(CONFIG_BLOCK_LEGACY_AUTOLOAD)) {
677 0 : blk_request_module(dev);
678 0 : inode = ilookup(blockdev_superblock, dev);
679 0 : if (inode)
680 0 : pr_warn_ratelimited(
681 : "block device autoloading is deprecated and will be removed.\n");
682 : }
683 0 : if (!inode)
684 : return NULL;
685 :
686 : /* switch from the inode reference to a device mode one: */
687 0 : bdev = &BDEV_I(inode)->bdev;
688 0 : if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
689 0 : bdev = NULL;
690 0 : iput(inode);
691 0 : return bdev;
692 : }
693 :
694 0 : void blkdev_put_no_open(struct block_device *bdev)
695 : {
696 0 : put_device(&bdev->bd_device);
697 0 : }
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 : */
720 0 : struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
721 : {
722 0 : bool unblock_events = true;
723 : struct block_device *bdev;
724 : struct gendisk *disk;
725 : int ret;
726 :
727 0 : ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
728 0 : MAJOR(dev), MINOR(dev),
729 0 : ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
730 0 : ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
731 : if (ret)
732 : return ERR_PTR(ret);
733 :
734 0 : bdev = blkdev_get_no_open(dev);
735 0 : if (!bdev)
736 : return ERR_PTR(-ENXIO);
737 0 : disk = bdev->bd_disk;
738 :
739 0 : if (mode & FMODE_EXCL) {
740 0 : ret = bd_prepare_to_claim(bdev, holder);
741 0 : if (ret)
742 : goto put_blkdev;
743 : }
744 :
745 0 : disk_block_events(disk);
746 :
747 0 : mutex_lock(&disk->open_mutex);
748 0 : ret = -ENXIO;
749 0 : if (!disk_live(disk))
750 : goto abort_claiming;
751 0 : if (!try_module_get(disk->fops->owner))
752 : goto abort_claiming;
753 0 : if (bdev_is_partition(bdev))
754 0 : ret = blkdev_get_part(bdev, mode);
755 : else
756 0 : ret = blkdev_get_whole(bdev, mode);
757 0 : if (ret)
758 : goto put_module;
759 0 : if (mode & FMODE_EXCL) {
760 0 : 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 0 : if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
770 0 : (disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) {
771 0 : bdev->bd_write_holder = true;
772 0 : unblock_events = false;
773 : }
774 : }
775 0 : mutex_unlock(&disk->open_mutex);
776 :
777 0 : if (unblock_events)
778 0 : disk_unblock_events(disk);
779 : return bdev;
780 : put_module:
781 : module_put(disk->fops->owner);
782 : abort_claiming:
783 0 : if (mode & FMODE_EXCL)
784 : bd_abort_claiming(bdev, holder);
785 0 : mutex_unlock(&disk->open_mutex);
786 0 : disk_unblock_events(disk);
787 : put_blkdev:
788 0 : blkdev_put_no_open(bdev);
789 0 : return ERR_PTR(ret);
790 : }
791 : EXPORT_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 : */
810 0 : struct 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 0 : error = lookup_bdev(path, &dev);
818 0 : if (error)
819 0 : return ERR_PTR(error);
820 :
821 0 : bdev = blkdev_get_by_dev(dev, mode, holder);
822 0 : if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
823 0 : blkdev_put(bdev, mode);
824 0 : return ERR_PTR(-EACCES);
825 : }
826 :
827 : return bdev;
828 : }
829 : EXPORT_SYMBOL(blkdev_get_by_path);
830 :
831 0 : void blkdev_put(struct block_device *bdev, fmode_t mode)
832 : {
833 0 : 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 0 : if (atomic_read(&bdev->bd_openers) == 1)
843 : sync_blockdev(bdev);
844 :
845 0 : mutex_lock(&disk->open_mutex);
846 0 : if (mode & FMODE_EXCL) {
847 0 : 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 0 : spin_lock(&bdev_lock);
856 :
857 0 : WARN_ON_ONCE(--bdev->bd_holders < 0);
858 0 : WARN_ON_ONCE(--whole->bd_holders < 0);
859 :
860 0 : if ((bdev_free = !bdev->bd_holders))
861 0 : bdev->bd_holder = NULL;
862 0 : if (!whole->bd_holders)
863 0 : whole->bd_holder = NULL;
864 :
865 0 : 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 0 : if (bdev_free && bdev->bd_write_holder) {
872 0 : disk_unblock_events(disk);
873 0 : 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 0 : disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
883 :
884 0 : if (bdev_is_partition(bdev))
885 0 : blkdev_put_part(bdev, mode);
886 : else
887 0 : blkdev_put_whole(bdev, mode);
888 0 : mutex_unlock(&disk->open_mutex);
889 :
890 0 : module_put(disk->fops->owner);
891 0 : blkdev_put_no_open(bdev);
892 0 : }
893 : EXPORT_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 : */
906 0 : int lookup_bdev(const char *pathname, dev_t *dev)
907 : {
908 : struct inode *inode;
909 : struct path path;
910 : int error;
911 :
912 0 : if (!pathname || !*pathname)
913 : return -EINVAL;
914 :
915 0 : error = kern_path(pathname, LOOKUP_FOLLOW, &path);
916 0 : if (error)
917 : return error;
918 :
919 0 : inode = d_backing_inode(path.dentry);
920 0 : error = -ENOTBLK;
921 0 : if (!S_ISBLK(inode->i_mode))
922 : goto out_path_put;
923 0 : error = -EACCES;
924 0 : if (!may_open_dev(&path))
925 : goto out_path_put;
926 :
927 0 : *dev = inode->i_rdev;
928 0 : error = 0;
929 : out_path_put:
930 0 : path_put(&path);
931 0 : return error;
932 : }
933 : EXPORT_SYMBOL(lookup_bdev);
934 :
935 0 : int __invalidate_device(struct block_device *bdev, bool kill_dirty)
936 : {
937 0 : struct super_block *sb = get_super(bdev);
938 0 : int res = 0;
939 :
940 0 : 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 0 : shrink_dcache_sb(sb);
948 0 : res = invalidate_inodes(sb, kill_dirty);
949 0 : drop_super(sb);
950 : }
951 0 : invalidate_bdev(bdev);
952 0 : return res;
953 : }
954 : EXPORT_SYMBOL(__invalidate_device);
955 :
956 0 : void sync_bdevs(bool wait)
957 : {
958 0 : struct inode *inode, *old_inode = NULL;
959 :
960 0 : spin_lock(&blockdev_superblock->s_inode_list_lock);
961 0 : list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
962 0 : struct address_space *mapping = inode->i_mapping;
963 : struct block_device *bdev;
964 :
965 0 : spin_lock(&inode->i_lock);
966 0 : if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
967 0 : mapping->nrpages == 0) {
968 0 : spin_unlock(&inode->i_lock);
969 0 : continue;
970 : }
971 0 : __iget(inode);
972 0 : spin_unlock(&inode->i_lock);
973 0 : 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 0 : iput(old_inode);
983 0 : old_inode = inode;
984 0 : bdev = I_BDEV(inode);
985 :
986 0 : mutex_lock(&bdev->bd_disk->open_mutex);
987 0 : if (!atomic_read(&bdev->bd_openers)) {
988 : ; /* skip */
989 0 : } 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 0 : filemap_fdatawait_keep_errors(inode->i_mapping);
997 : } else {
998 0 : filemap_fdatawrite(inode->i_mapping);
999 : }
1000 0 : mutex_unlock(&bdev->bd_disk->open_mutex);
1001 :
1002 0 : spin_lock(&blockdev_superblock->s_inode_list_lock);
1003 : }
1004 0 : spin_unlock(&blockdev_superblock->s_inode_list_lock);
1005 0 : iput(old_inode);
1006 0 : }
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 : */
1015 0 : void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
1016 : {
1017 : struct block_device *bdev;
1018 :
1019 0 : bdev = blkdev_get_no_open(inode->i_rdev);
1020 0 : if (!bdev)
1021 : return;
1022 :
1023 0 : stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
1024 0 : stat->dio_offset_align = bdev_logical_block_size(bdev);
1025 0 : stat->result_mask |= STATX_DIOALIGN;
1026 :
1027 : blkdev_put_no_open(bdev);
1028 : }
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