Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 | 2 | /* |
1da177e4 LT |
3 | * Copyright (C) 1991, 1992 Linus Torvalds |
4 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE | |
7b51e703 | 5 | * Copyright (C) 2016 - 2020 Christoph Hellwig |
1da177e4 LT |
6 | */ |
7 | ||
1da177e4 LT |
8 | #include <linux/init.h> |
9 | #include <linux/mm.h> | |
1da177e4 LT |
10 | #include <linux/slab.h> |
11 | #include <linux/kmod.h> | |
12 | #include <linux/major.h> | |
7db9cfd3 | 13 | #include <linux/device_cgroup.h> |
1da177e4 | 14 | #include <linux/blkdev.h> |
fe45e630 | 15 | #include <linux/blk-integrity.h> |
66114cad | 16 | #include <linux/backing-dev.h> |
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/blkpg.h> | |
b502bd11 | 19 | #include <linux/magic.h> |
1da177e4 | 20 | #include <linux/buffer_head.h> |
ff01bb48 | 21 | #include <linux/swap.h> |
811d736f | 22 | #include <linux/writeback.h> |
1da177e4 | 23 | #include <linux/mount.h> |
9030d16e | 24 | #include <linux/pseudo_fs.h> |
1da177e4 LT |
25 | #include <linux/uio.h> |
26 | #include <linux/namei.h> | |
15e3d2c5 | 27 | #include <linux/part_stat.h> |
7c0f6ba6 | 28 | #include <linux/uaccess.h> |
2d985f8c | 29 | #include <linux/stat.h> |
0dca4462 CH |
30 | #include "../fs/internal.h" |
31 | #include "blk.h" | |
1da177e4 | 32 | |
ed5cc702 JK |
33 | /* Should we allow writing to mounted block devices? */ |
34 | static bool bdev_allow_write_mounted = IS_ENABLED(CONFIG_BLK_DEV_WRITE_MOUNTED); | |
35 | ||
1da177e4 LT |
36 | struct bdev_inode { |
37 | struct block_device bdev; | |
38 | struct inode vfs_inode; | |
39 | }; | |
40 | ||
41 | static inline struct bdev_inode *BDEV_I(struct inode *inode) | |
42 | { | |
43 | return container_of(inode, struct bdev_inode, vfs_inode); | |
44 | } | |
45 | ||
ff5053f6 | 46 | struct block_device *I_BDEV(struct inode *inode) |
1da177e4 LT |
47 | { |
48 | return &BDEV_I(inode)->bdev; | |
49 | } | |
1da177e4 LT |
50 | EXPORT_SYMBOL(I_BDEV); |
51 | ||
f3a60882 CB |
52 | struct block_device *file_bdev(struct file *bdev_file) |
53 | { | |
54 | struct bdev_handle *handle = bdev_file->private_data; | |
55 | return handle->bdev; | |
56 | } | |
57 | EXPORT_SYMBOL(file_bdev); | |
58 | ||
dbd3ca50 | 59 | static void bdev_write_inode(struct block_device *bdev) |
564f00f6 | 60 | { |
dbd3ca50 VG |
61 | struct inode *inode = bdev->bd_inode; |
62 | int ret; | |
63 | ||
564f00f6 CH |
64 | spin_lock(&inode->i_lock); |
65 | while (inode->i_state & I_DIRTY) { | |
66 | spin_unlock(&inode->i_lock); | |
dbd3ca50 | 67 | ret = write_inode_now(inode, true); |
5bf83e9a CH |
68 | if (ret) |
69 | pr_warn_ratelimited( | |
70 | "VFS: Dirty inode writeback failed for block device %pg (err=%d).\n", | |
71 | bdev, ret); | |
564f00f6 CH |
72 | spin_lock(&inode->i_lock); |
73 | } | |
74 | spin_unlock(&inode->i_lock); | |
75 | } | |
76 | ||
f9a14399 | 77 | /* Kill _all_ buffers and pagecache , dirty or not.. */ |
3373a346 | 78 | static void kill_bdev(struct block_device *bdev) |
1da177e4 | 79 | { |
ff01bb48 AV |
80 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
81 | ||
7716506a | 82 | if (mapping_empty(mapping)) |
f9a14399 | 83 | return; |
ff01bb48 | 84 | |
f9a14399 | 85 | invalidate_bh_lrus(); |
ff01bb48 | 86 | truncate_inode_pages(mapping, 0); |
3373a346 | 87 | } |
ff01bb48 AV |
88 | |
89 | /* Invalidate clean unused buffers and pagecache. */ | |
90 | void invalidate_bdev(struct block_device *bdev) | |
91 | { | |
92 | struct address_space *mapping = bdev->bd_inode->i_mapping; | |
93 | ||
a5f6a6a9 AR |
94 | if (mapping->nrpages) { |
95 | invalidate_bh_lrus(); | |
96 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ | |
97 | invalidate_mapping_pages(mapping, 0, -1); | |
98 | } | |
ff01bb48 AV |
99 | } |
100 | EXPORT_SYMBOL(invalidate_bdev); | |
1da177e4 | 101 | |
384d87ef JK |
102 | /* |
103 | * Drop all buffers & page cache for given bdev range. This function bails | |
104 | * with error if bdev has other exclusive owner (such as filesystem). | |
105 | */ | |
05bdb996 | 106 | int truncate_bdev_range(struct block_device *bdev, blk_mode_t mode, |
384d87ef JK |
107 | loff_t lstart, loff_t lend) |
108 | { | |
384d87ef JK |
109 | /* |
110 | * If we don't hold exclusive handle for the device, upgrade to it | |
111 | * while we discard the buffer cache to avoid discarding buffers | |
112 | * under live filesystem. | |
113 | */ | |
05bdb996 | 114 | if (!(mode & BLK_OPEN_EXCL)) { |
0718afd4 | 115 | int err = bd_prepare_to_claim(bdev, truncate_bdev_range, NULL); |
384d87ef | 116 | if (err) |
56887cff | 117 | goto invalidate; |
384d87ef | 118 | } |
37c3fc9a | 119 | |
384d87ef | 120 | truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); |
05bdb996 | 121 | if (!(mode & BLK_OPEN_EXCL)) |
37c3fc9a | 122 | bd_abort_claiming(bdev, truncate_bdev_range); |
384d87ef | 123 | return 0; |
56887cff JK |
124 | |
125 | invalidate: | |
126 | /* | |
127 | * Someone else has handle exclusively open. Try invalidating instead. | |
128 | * The 'end' argument is inclusive so the rounding is safe. | |
129 | */ | |
130 | return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, | |
131 | lstart >> PAGE_SHIFT, | |
132 | lend >> PAGE_SHIFT); | |
384d87ef | 133 | } |
384d87ef | 134 | |
04906b2f JK |
135 | static void set_init_blocksize(struct block_device *bdev) |
136 | { | |
8dc932d3 MM |
137 | unsigned int bsize = bdev_logical_block_size(bdev); |
138 | loff_t size = i_size_read(bdev->bd_inode); | |
139 | ||
140 | while (bsize < PAGE_SIZE) { | |
141 | if (size & bsize) | |
142 | break; | |
143 | bsize <<= 1; | |
144 | } | |
145 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
04906b2f JK |
146 | } |
147 | ||
1da177e4 LT |
148 | int set_blocksize(struct block_device *bdev, int size) |
149 | { | |
150 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
1368c4f2 | 151 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) |
1da177e4 LT |
152 | return -EINVAL; |
153 | ||
154 | /* Size cannot be smaller than the size supported by the device */ | |
e1defc4f | 155 | if (size < bdev_logical_block_size(bdev)) |
1da177e4 LT |
156 | return -EINVAL; |
157 | ||
158 | /* Don't change the size if it is same as current */ | |
6b7b181b | 159 | if (bdev->bd_inode->i_blkbits != blksize_bits(size)) { |
1da177e4 | 160 | sync_blockdev(bdev); |
1da177e4 LT |
161 | bdev->bd_inode->i_blkbits = blksize_bits(size); |
162 | kill_bdev(bdev); | |
163 | } | |
164 | return 0; | |
165 | } | |
166 | ||
167 | EXPORT_SYMBOL(set_blocksize); | |
168 | ||
169 | int sb_set_blocksize(struct super_block *sb, int size) | |
170 | { | |
1da177e4 LT |
171 | if (set_blocksize(sb->s_bdev, size)) |
172 | return 0; | |
173 | /* If we get here, we know size is power of two | |
174 | * and it's value is between 512 and PAGE_SIZE */ | |
175 | sb->s_blocksize = size; | |
38885bd4 | 176 | sb->s_blocksize_bits = blksize_bits(size); |
1da177e4 LT |
177 | return sb->s_blocksize; |
178 | } | |
179 | ||
180 | EXPORT_SYMBOL(sb_set_blocksize); | |
181 | ||
182 | int sb_min_blocksize(struct super_block *sb, int size) | |
183 | { | |
e1defc4f | 184 | int minsize = bdev_logical_block_size(sb->s_bdev); |
1da177e4 LT |
185 | if (size < minsize) |
186 | size = minsize; | |
187 | return sb_set_blocksize(sb, size); | |
188 | } | |
189 | ||
190 | EXPORT_SYMBOL(sb_min_blocksize); | |
191 | ||
70164eb6 | 192 | int sync_blockdev_nowait(struct block_device *bdev) |
5cee5815 JK |
193 | { |
194 | if (!bdev) | |
195 | return 0; | |
70164eb6 | 196 | return filemap_flush(bdev->bd_inode->i_mapping); |
5cee5815 | 197 | } |
70164eb6 | 198 | EXPORT_SYMBOL_GPL(sync_blockdev_nowait); |
5cee5815 | 199 | |
585d3bc0 NP |
200 | /* |
201 | * Write out and wait upon all the dirty data associated with a block | |
202 | * device via its mapping. Does not take the superblock lock. | |
203 | */ | |
204 | int sync_blockdev(struct block_device *bdev) | |
205 | { | |
70164eb6 CH |
206 | if (!bdev) |
207 | return 0; | |
208 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); | |
585d3bc0 NP |
209 | } |
210 | EXPORT_SYMBOL(sync_blockdev); | |
211 | ||
97d6fb1b YM |
212 | int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend) |
213 | { | |
214 | return filemap_write_and_wait_range(bdev->bd_inode->i_mapping, | |
215 | lstart, lend); | |
216 | } | |
217 | EXPORT_SYMBOL(sync_blockdev_range); | |
218 | ||
585d3bc0 | 219 | /** |
982c3b30 | 220 | * bdev_freeze - lock a filesystem and force it into a consistent state |
585d3bc0 NP |
221 | * @bdev: blockdevice to lock |
222 | * | |
585d3bc0 NP |
223 | * If a superblock is found on this device, we take the s_umount semaphore |
224 | * on it to make sure nobody unmounts until the snapshot creation is done. | |
225 | * The reference counter (bd_fsfreeze_count) guarantees that only the last | |
226 | * unfreeze process can unfreeze the frozen filesystem actually when multiple | |
982c3b30 CB |
227 | * freeze requests arrive simultaneously. It counts up in bdev_freeze() and |
228 | * count down in bdev_thaw(). When it becomes 0, thaw_bdev() will unfreeze | |
585d3bc0 | 229 | * actually. |
982c3b30 CB |
230 | * |
231 | * Return: On success zero is returned, negative error code on failure. | |
585d3bc0 | 232 | */ |
982c3b30 | 233 | int bdev_freeze(struct block_device *bdev) |
585d3bc0 | 234 | { |
585d3bc0 NP |
235 | int error = 0; |
236 | ||
237 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
040f04bd | 238 | |
49ef8832 CB |
239 | if (atomic_inc_return(&bdev->bd_fsfreeze_count) > 1) { |
240 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
241 | return 0; | |
585d3bc0 | 242 | } |
040f04bd | 243 | |
49ef8832 CB |
244 | mutex_lock(&bdev->bd_holder_lock); |
245 | if (bdev->bd_holder_ops && bdev->bd_holder_ops->freeze) { | |
246 | error = bdev->bd_holder_ops->freeze(bdev); | |
247 | lockdep_assert_not_held(&bdev->bd_holder_lock); | |
248 | } else { | |
249 | mutex_unlock(&bdev->bd_holder_lock); | |
250 | error = sync_blockdev(bdev); | |
585d3bc0 | 251 | } |
040f04bd | 252 | |
49ef8832 CB |
253 | if (error) |
254 | atomic_dec(&bdev->bd_fsfreeze_count); | |
255 | ||
585d3bc0 | 256 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
040f04bd | 257 | return error; |
585d3bc0 | 258 | } |
982c3b30 | 259 | EXPORT_SYMBOL(bdev_freeze); |
585d3bc0 NP |
260 | |
261 | /** | |
982c3b30 | 262 | * bdev_thaw - unlock filesystem |
585d3bc0 | 263 | * @bdev: blockdevice to unlock |
585d3bc0 | 264 | * |
982c3b30 CB |
265 | * Unlocks the filesystem and marks it writeable again after bdev_freeze(). |
266 | * | |
267 | * Return: On success zero is returned, negative error code on failure. | |
585d3bc0 | 268 | */ |
982c3b30 | 269 | int bdev_thaw(struct block_device *bdev) |
585d3bc0 | 270 | { |
49ef8832 | 271 | int error = -EINVAL, nr_freeze; |
585d3bc0 NP |
272 | |
273 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
49ef8832 CB |
274 | |
275 | /* | |
276 | * If this returns < 0 it means that @bd_fsfreeze_count was | |
277 | * already 0 and no decrement was performed. | |
278 | */ | |
279 | nr_freeze = atomic_dec_if_positive(&bdev->bd_fsfreeze_count); | |
280 | if (nr_freeze < 0) | |
18e9e510 | 281 | goto out; |
4504230a CH |
282 | |
283 | error = 0; | |
49ef8832 | 284 | if (nr_freeze > 0) |
18e9e510 | 285 | goto out; |
4504230a | 286 | |
49ef8832 CB |
287 | mutex_lock(&bdev->bd_holder_lock); |
288 | if (bdev->bd_holder_ops && bdev->bd_holder_ops->thaw) { | |
289 | error = bdev->bd_holder_ops->thaw(bdev); | |
290 | lockdep_assert_not_held(&bdev->bd_holder_lock); | |
291 | } else { | |
292 | mutex_unlock(&bdev->bd_holder_lock); | |
293 | } | |
4504230a | 294 | |
997198ba | 295 | if (error) |
49ef8832 | 296 | atomic_inc(&bdev->bd_fsfreeze_count); |
18e9e510 | 297 | out: |
585d3bc0 | 298 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
997198ba | 299 | return error; |
585d3bc0 | 300 | } |
982c3b30 | 301 | EXPORT_SYMBOL(bdev_thaw); |
585d3bc0 | 302 | |
1da177e4 LT |
303 | /* |
304 | * pseudo-fs | |
305 | */ | |
306 | ||
74e6464a | 307 | static __cacheline_aligned_in_smp DEFINE_MUTEX(bdev_lock); |
68279f9c | 308 | static struct kmem_cache *bdev_cachep __ro_after_init; |
1da177e4 LT |
309 | |
310 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
311 | { | |
fd60b288 | 312 | struct bdev_inode *ei = alloc_inode_sb(sb, bdev_cachep, GFP_KERNEL); |
2d2f6f1b | 313 | |
1da177e4 LT |
314 | if (!ei) |
315 | return NULL; | |
2d2f6f1b | 316 | memset(&ei->bdev, 0, sizeof(ei->bdev)); |
1da177e4 LT |
317 | return &ei->vfs_inode; |
318 | } | |
319 | ||
41149cb0 | 320 | static void bdev_free_inode(struct inode *inode) |
1da177e4 | 321 | { |
15e3d2c5 CH |
322 | struct block_device *bdev = I_BDEV(inode); |
323 | ||
324 | free_percpu(bdev->bd_stats); | |
231926db | 325 | kfree(bdev->bd_meta_info); |
15e3d2c5 | 326 | |
889c05cc CH |
327 | if (!bdev_is_partition(bdev)) { |
328 | if (bdev->bd_disk && bdev->bd_disk->bdi) | |
329 | bdi_put(bdev->bd_disk->bdi); | |
340e8457 | 330 | kfree(bdev->bd_disk); |
889c05cc | 331 | } |
9451aa0a CH |
332 | |
333 | if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR) | |
334 | blk_free_ext_minor(MINOR(bdev->bd_dev)); | |
335 | ||
41149cb0 | 336 | kmem_cache_free(bdev_cachep, BDEV_I(inode)); |
fa0d7e3d NP |
337 | } |
338 | ||
e6cb5382 | 339 | static void init_once(void *data) |
1da177e4 | 340 | { |
e6cb5382 | 341 | struct bdev_inode *ei = data; |
1da177e4 | 342 | |
a35afb83 | 343 | inode_init_once(&ei->vfs_inode); |
1da177e4 LT |
344 | } |
345 | ||
b57922d9 | 346 | static void bdev_evict_inode(struct inode *inode) |
1da177e4 | 347 | { |
91b0abe3 | 348 | truncate_inode_pages_final(&inode->i_data); |
b57922d9 | 349 | invalidate_inode_buffers(inode); /* is it needed here? */ |
dbd5768f | 350 | clear_inode(inode); |
1da177e4 LT |
351 | } |
352 | ||
ee9b6d61 | 353 | static const struct super_operations bdev_sops = { |
1da177e4 LT |
354 | .statfs = simple_statfs, |
355 | .alloc_inode = bdev_alloc_inode, | |
41149cb0 | 356 | .free_inode = bdev_free_inode, |
1da177e4 | 357 | .drop_inode = generic_delete_inode, |
b57922d9 | 358 | .evict_inode = bdev_evict_inode, |
1da177e4 LT |
359 | }; |
360 | ||
9030d16e | 361 | static int bd_init_fs_context(struct fs_context *fc) |
1da177e4 | 362 | { |
9030d16e DH |
363 | struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC); |
364 | if (!ctx) | |
365 | return -ENOMEM; | |
366 | fc->s_iflags |= SB_I_CGROUPWB; | |
367 | ctx->ops = &bdev_sops; | |
368 | return 0; | |
1da177e4 LT |
369 | } |
370 | ||
371 | static struct file_system_type bd_type = { | |
372 | .name = "bdev", | |
9030d16e | 373 | .init_fs_context = bd_init_fs_context, |
1da177e4 LT |
374 | .kill_sb = kill_anon_super, |
375 | }; | |
376 | ||
68279f9c | 377 | struct super_block *blockdev_superblock __ro_after_init; |
f3a60882 | 378 | struct vfsmount *blockdev_mnt __ro_after_init; |
a212b105 | 379 | EXPORT_SYMBOL_GPL(blockdev_superblock); |
1da177e4 LT |
380 | |
381 | void __init bdev_cache_init(void) | |
382 | { | |
383 | int err; | |
c2acf7b9 | 384 | |
1da177e4 | 385 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
fffb60f9 | 386 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
5d097056 | 387 | SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), |
20c2df83 | 388 | init_once); |
1da177e4 LT |
389 | err = register_filesystem(&bd_type); |
390 | if (err) | |
391 | panic("Cannot register bdev pseudo-fs"); | |
f3a60882 CB |
392 | blockdev_mnt = kern_mount(&bd_type); |
393 | if (IS_ERR(blockdev_mnt)) | |
1da177e4 | 394 | panic("Cannot create bdev pseudo-fs"); |
f3a60882 | 395 | blockdev_superblock = blockdev_mnt->mnt_sb; /* For writeback */ |
1da177e4 LT |
396 | } |
397 | ||
22ae8ce8 | 398 | struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) |
1da177e4 LT |
399 | { |
400 | struct block_device *bdev; | |
401 | struct inode *inode; | |
402 | ||
22ae8ce8 | 403 | inode = new_inode(blockdev_superblock); |
1da177e4 LT |
404 | if (!inode) |
405 | return NULL; | |
22ae8ce8 CH |
406 | inode->i_mode = S_IFBLK; |
407 | inode->i_rdev = 0; | |
408 | inode->i_data.a_ops = &def_blk_aops; | |
409 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
410 | ||
411 | bdev = I_BDEV(inode); | |
e6cb5382 | 412 | mutex_init(&bdev->bd_fsfreeze_mutex); |
22ae8ce8 | 413 | spin_lock_init(&bdev->bd_size_lock); |
0718afd4 | 414 | mutex_init(&bdev->bd_holder_lock); |
22ae8ce8 | 415 | bdev->bd_partno = partno; |
22ae8ce8 | 416 | bdev->bd_inode = inode; |
17220ca5 | 417 | bdev->bd_queue = disk->queue; |
38c8e3df ML |
418 | if (partno) |
419 | bdev->bd_has_submit_bio = disk->part0->bd_has_submit_bio; | |
420 | else | |
421 | bdev->bd_has_submit_bio = false; | |
15e3d2c5 CH |
422 | bdev->bd_stats = alloc_percpu(struct disk_stats); |
423 | if (!bdev->bd_stats) { | |
424 | iput(inode); | |
425 | return NULL; | |
426 | } | |
06cc978d | 427 | bdev->bd_disk = disk; |
22ae8ce8 CH |
428 | return bdev; |
429 | } | |
1da177e4 | 430 | |
83794367 DLM |
431 | void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors) |
432 | { | |
433 | spin_lock(&bdev->bd_size_lock); | |
434 | i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT); | |
435 | bdev->bd_nr_sectors = sectors; | |
436 | spin_unlock(&bdev->bd_size_lock); | |
437 | } | |
438 | ||
22ae8ce8 CH |
439 | void bdev_add(struct block_device *bdev, dev_t dev) |
440 | { | |
1898efcd CH |
441 | if (bdev_stable_writes(bdev)) |
442 | mapping_set_stable_writes(bdev->bd_inode->i_mapping); | |
22ae8ce8 CH |
443 | bdev->bd_dev = dev; |
444 | bdev->bd_inode->i_rdev = dev; | |
445 | bdev->bd_inode->i_ino = dev; | |
446 | insert_inode_hash(bdev->bd_inode); | |
447 | } | |
1da177e4 | 448 | |
1da177e4 LT |
449 | long nr_blockdev_pages(void) |
450 | { | |
1008fe6d | 451 | struct inode *inode; |
1da177e4 | 452 | long ret = 0; |
1008fe6d CH |
453 | |
454 | spin_lock(&blockdev_superblock->s_inode_list_lock); | |
455 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) | |
456 | ret += inode->i_mapping->nrpages; | |
457 | spin_unlock(&blockdev_superblock->s_inode_list_lock); | |
458 | ||
1da177e4 LT |
459 | return ret; |
460 | } | |
461 | ||
1a3cbbc5 TH |
462 | /** |
463 | * bd_may_claim - test whether a block device can be claimed | |
464 | * @bdev: block device of interest | |
1a3cbbc5 | 465 | * @holder: holder trying to claim @bdev |
0718afd4 | 466 | * @hops: holder ops |
1a3cbbc5 | 467 | * |
25985edc | 468 | * Test whether @bdev can be claimed by @holder. |
1a3cbbc5 | 469 | * |
1a3cbbc5 TH |
470 | * RETURNS: |
471 | * %true if @bdev can be claimed, %false otherwise. | |
472 | */ | |
0718afd4 CH |
473 | static bool bd_may_claim(struct block_device *bdev, void *holder, |
474 | const struct blk_holder_ops *hops) | |
ae5f855e CH |
475 | { |
476 | struct block_device *whole = bdev_whole(bdev); | |
477 | ||
74e6464a CH |
478 | lockdep_assert_held(&bdev_lock); |
479 | ||
ae5f855e CH |
480 | if (bdev->bd_holder) { |
481 | /* | |
482 | * The same holder can always re-claim. | |
483 | */ | |
0718afd4 CH |
484 | if (bdev->bd_holder == holder) { |
485 | if (WARN_ON_ONCE(bdev->bd_holder_ops != hops)) | |
486 | return false; | |
ae5f855e | 487 | return true; |
0718afd4 | 488 | } |
ae5f855e CH |
489 | return false; |
490 | } | |
491 | ||
492 | /* | |
493 | * If the whole devices holder is set to bd_may_claim, a partition on | |
494 | * the device is claimed, but not the whole device. | |
495 | */ | |
496 | if (whole != bdev && | |
497 | whole->bd_holder && whole->bd_holder != bd_may_claim) | |
498 | return false; | |
499 | return true; | |
1a3cbbc5 TH |
500 | } |
501 | ||
6b4517a7 | 502 | /** |
58e46ed9 | 503 | * bd_prepare_to_claim - claim a block device |
6b4517a7 | 504 | * @bdev: block device of interest |
6b4517a7 | 505 | * @holder: holder trying to claim @bdev |
0718afd4 | 506 | * @hops: holder ops. |
6b4517a7 | 507 | * |
58e46ed9 CH |
508 | * Claim @bdev. This function fails if @bdev is already claimed by another |
509 | * holder and waits if another claiming is in progress. return, the caller | |
510 | * has ownership of bd_claiming and bd_holder[s]. | |
6b4517a7 TH |
511 | * |
512 | * RETURNS: | |
513 | * 0 if @bdev can be claimed, -EBUSY otherwise. | |
514 | */ | |
0718afd4 CH |
515 | int bd_prepare_to_claim(struct block_device *bdev, void *holder, |
516 | const struct blk_holder_ops *hops) | |
6b4517a7 | 517 | { |
37c3fc9a CH |
518 | struct block_device *whole = bdev_whole(bdev); |
519 | ||
520 | if (WARN_ON_ONCE(!holder)) | |
521 | return -EINVAL; | |
6b4517a7 | 522 | retry: |
74e6464a | 523 | mutex_lock(&bdev_lock); |
6b4517a7 | 524 | /* if someone else claimed, fail */ |
0718afd4 | 525 | if (!bd_may_claim(bdev, holder, hops)) { |
74e6464a | 526 | mutex_unlock(&bdev_lock); |
6b4517a7 | 527 | return -EBUSY; |
58e46ed9 | 528 | } |
6b4517a7 | 529 | |
e75aa858 TH |
530 | /* if claiming is already in progress, wait for it to finish */ |
531 | if (whole->bd_claiming) { | |
6b4517a7 TH |
532 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); |
533 | DEFINE_WAIT(wait); | |
534 | ||
535 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
74e6464a | 536 | mutex_unlock(&bdev_lock); |
6b4517a7 TH |
537 | schedule(); |
538 | finish_wait(wq, &wait); | |
6b4517a7 TH |
539 | goto retry; |
540 | } | |
541 | ||
542 | /* yay, all mine */ | |
58e46ed9 | 543 | whole->bd_claiming = holder; |
74e6464a | 544 | mutex_unlock(&bdev_lock); |
6b4517a7 TH |
545 | return 0; |
546 | } | |
ecbe6bc0 | 547 | EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */ |
6b4517a7 | 548 | |
89e524c0 JK |
549 | static void bd_clear_claiming(struct block_device *whole, void *holder) |
550 | { | |
551 | lockdep_assert_held(&bdev_lock); | |
552 | /* tell others that we're done */ | |
553 | BUG_ON(whole->bd_claiming != holder); | |
554 | whole->bd_claiming = NULL; | |
555 | wake_up_bit(&whole->bd_claiming, 0); | |
556 | } | |
557 | ||
558 | /** | |
559 | * bd_finish_claiming - finish claiming of a block device | |
560 | * @bdev: block device of interest | |
89e524c0 | 561 | * @holder: holder that has claimed @bdev |
017fb83e | 562 | * @hops: block device holder operations |
89e524c0 JK |
563 | * |
564 | * Finish exclusive open of a block device. Mark the device as exlusively | |
565 | * open by the holder and wake up all waiters for exclusive open to finish. | |
566 | */ | |
0718afd4 CH |
567 | static void bd_finish_claiming(struct block_device *bdev, void *holder, |
568 | const struct blk_holder_ops *hops) | |
89e524c0 | 569 | { |
37c3fc9a CH |
570 | struct block_device *whole = bdev_whole(bdev); |
571 | ||
74e6464a | 572 | mutex_lock(&bdev_lock); |
0718afd4 | 573 | BUG_ON(!bd_may_claim(bdev, holder, hops)); |
89e524c0 JK |
574 | /* |
575 | * Note that for a whole device bd_holders will be incremented twice, | |
576 | * and bd_holder will be set to bd_may_claim before being set to holder | |
577 | */ | |
578 | whole->bd_holders++; | |
579 | whole->bd_holder = bd_may_claim; | |
580 | bdev->bd_holders++; | |
0718afd4 | 581 | mutex_lock(&bdev->bd_holder_lock); |
89e524c0 | 582 | bdev->bd_holder = holder; |
0718afd4 CH |
583 | bdev->bd_holder_ops = hops; |
584 | mutex_unlock(&bdev->bd_holder_lock); | |
89e524c0 | 585 | bd_clear_claiming(whole, holder); |
74e6464a | 586 | mutex_unlock(&bdev_lock); |
89e524c0 | 587 | } |
89e524c0 JK |
588 | |
589 | /** | |
590 | * bd_abort_claiming - abort claiming of a block device | |
591 | * @bdev: block device of interest | |
89e524c0 JK |
592 | * @holder: holder that has claimed @bdev |
593 | * | |
594 | * Abort claiming of a block device when the exclusive open failed. This can be | |
595 | * also used when exclusive open is not actually desired and we just needed | |
596 | * to block other exclusive openers for a while. | |
597 | */ | |
37c3fc9a | 598 | void bd_abort_claiming(struct block_device *bdev, void *holder) |
89e524c0 | 599 | { |
74e6464a | 600 | mutex_lock(&bdev_lock); |
37c3fc9a | 601 | bd_clear_claiming(bdev_whole(bdev), holder); |
74e6464a | 602 | mutex_unlock(&bdev_lock); |
89e524c0 JK |
603 | } |
604 | EXPORT_SYMBOL(bd_abort_claiming); | |
6b4517a7 | 605 | |
2736e8ee | 606 | static void bd_end_claim(struct block_device *bdev, void *holder) |
0783b1a7 CH |
607 | { |
608 | struct block_device *whole = bdev_whole(bdev); | |
609 | bool unblock = false; | |
610 | ||
611 | /* | |
612 | * Release a claim on the device. The holder fields are protected with | |
613 | * bdev_lock. open_mutex is used to synchronize disk_holder unlinking. | |
614 | */ | |
74e6464a | 615 | mutex_lock(&bdev_lock); |
2736e8ee | 616 | WARN_ON_ONCE(bdev->bd_holder != holder); |
0783b1a7 CH |
617 | WARN_ON_ONCE(--bdev->bd_holders < 0); |
618 | WARN_ON_ONCE(--whole->bd_holders < 0); | |
619 | if (!bdev->bd_holders) { | |
0718afd4 | 620 | mutex_lock(&bdev->bd_holder_lock); |
0783b1a7 | 621 | bdev->bd_holder = NULL; |
0718afd4 CH |
622 | bdev->bd_holder_ops = NULL; |
623 | mutex_unlock(&bdev->bd_holder_lock); | |
0783b1a7 CH |
624 | if (bdev->bd_write_holder) |
625 | unblock = true; | |
626 | } | |
627 | if (!whole->bd_holders) | |
628 | whole->bd_holder = NULL; | |
74e6464a | 629 | mutex_unlock(&bdev_lock); |
0783b1a7 CH |
630 | |
631 | /* | |
632 | * If this was the last claim, remove holder link and unblock evpoll if | |
633 | * it was a write holder. | |
634 | */ | |
635 | if (unblock) { | |
636 | disk_unblock_events(bdev->bd_disk); | |
637 | bdev->bd_write_holder = false; | |
638 | } | |
639 | } | |
640 | ||
c8276b95 CH |
641 | static void blkdev_flush_mapping(struct block_device *bdev) |
642 | { | |
643 | WARN_ON_ONCE(bdev->bd_holders); | |
644 | sync_blockdev(bdev); | |
645 | kill_bdev(bdev); | |
646 | bdev_write_inode(bdev); | |
647 | } | |
37be4124 | 648 | |
05bdb996 | 649 | static int blkdev_get_whole(struct block_device *bdev, blk_mode_t mode) |
a1548b67 | 650 | { |
142fe8f4 | 651 | struct gendisk *disk = bdev->bd_disk; |
af22fef3 | 652 | int ret; |
a1548b67 | 653 | |
362529d9 | 654 | if (disk->fops->open) { |
d32e2bf8 | 655 | ret = disk->fops->open(disk, mode); |
362529d9 CH |
656 | if (ret) { |
657 | /* avoid ghost partitions on a removed medium */ | |
658 | if (ret == -ENOMEDIUM && | |
659 | test_bit(GD_NEED_PART_SCAN, &disk->state)) | |
0384264e | 660 | bdev_disk_changed(disk, true); |
362529d9 CH |
661 | return ret; |
662 | } | |
d981cb5b | 663 | } |
a1548b67 | 664 | |
9acf381f | 665 | if (!atomic_read(&bdev->bd_openers)) |
362529d9 | 666 | set_init_blocksize(bdev); |
362529d9 | 667 | if (test_bit(GD_NEED_PART_SCAN, &disk->state)) |
0384264e | 668 | bdev_disk_changed(disk, false); |
9acf381f | 669 | atomic_inc(&bdev->bd_openers); |
483546c1 | 670 | return 0; |
362529d9 | 671 | } |
a1548b67 | 672 | |
ae220766 | 673 | static void blkdev_put_whole(struct block_device *bdev) |
c8276b95 | 674 | { |
9acf381f | 675 | if (atomic_dec_and_test(&bdev->bd_openers)) |
c8276b95 CH |
676 | blkdev_flush_mapping(bdev); |
677 | if (bdev->bd_disk->fops->release) | |
ae220766 | 678 | bdev->bd_disk->fops->release(bdev->bd_disk); |
a1548b67 CH |
679 | } |
680 | ||
05bdb996 | 681 | static int blkdev_get_part(struct block_device *part, blk_mode_t mode) |
1da177e4 | 682 | { |
362529d9 | 683 | struct gendisk *disk = part->bd_disk; |
362529d9 | 684 | int ret; |
5b642d8b | 685 | |
9d3b8813 | 686 | ret = blkdev_get_whole(bdev_whole(part), mode); |
a8698707 | 687 | if (ret) |
9d3b8813 | 688 | return ret; |
7e69723f | 689 | |
362529d9 CH |
690 | ret = -ENXIO; |
691 | if (!bdev_nr_sectors(part)) | |
692 | goto out_blkdev_put; | |
7e69723f | 693 | |
9d1c9287 CH |
694 | if (!atomic_read(&part->bd_openers)) { |
695 | disk->open_partitions++; | |
696 | set_init_blocksize(part); | |
697 | } | |
9acf381f | 698 | atomic_inc(&part->bd_openers); |
1da177e4 | 699 | return 0; |
5a023cdb | 700 | |
362529d9 | 701 | out_blkdev_put: |
ae220766 | 702 | blkdev_put_whole(bdev_whole(part)); |
362529d9 | 703 | return ret; |
1da177e4 | 704 | } |
5b56b6ed | 705 | |
ae220766 | 706 | static void blkdev_put_part(struct block_device *part) |
c8276b95 CH |
707 | { |
708 | struct block_device *whole = bdev_whole(part); | |
03e26279 | 709 | |
9d1c9287 CH |
710 | if (atomic_dec_and_test(&part->bd_openers)) { |
711 | blkdev_flush_mapping(part); | |
712 | whole->bd_disk->open_partitions--; | |
713 | } | |
ae220766 | 714 | blkdev_put_whole(whole); |
1da177e4 LT |
715 | } |
716 | ||
22ae8ce8 CH |
717 | struct block_device *blkdev_get_no_open(dev_t dev) |
718 | { | |
719 | struct block_device *bdev; | |
9d3b8813 | 720 | struct inode *inode; |
22ae8ce8 | 721 | |
9d3b8813 | 722 | inode = ilookup(blockdev_superblock, dev); |
fbdee71b | 723 | if (!inode && IS_ENABLED(CONFIG_BLOCK_LEGACY_AUTOLOAD)) { |
22ae8ce8 | 724 | blk_request_module(dev); |
9d3b8813 | 725 | inode = ilookup(blockdev_superblock, dev); |
fbdee71b CH |
726 | if (inode) |
727 | pr_warn_ratelimited( | |
451f0b6f | 728 | "block device autoloading is deprecated and will be removed.\n"); |
22ae8ce8 | 729 | } |
fbdee71b CH |
730 | if (!inode) |
731 | return NULL; | |
22ae8ce8 | 732 | |
9d3b8813 CH |
733 | /* switch from the inode reference to a device mode one: */ |
734 | bdev = &BDEV_I(inode)->bdev; | |
735 | if (!kobject_get_unless_zero(&bdev->bd_device.kobj)) | |
736 | bdev = NULL; | |
737 | iput(inode); | |
22ae8ce8 | 738 | return bdev; |
22ae8ce8 CH |
739 | } |
740 | ||
741 | void blkdev_put_no_open(struct block_device *bdev) | |
742 | { | |
9d3b8813 | 743 | put_device(&bdev->bd_device); |
22ae8ce8 | 744 | } |
ed5cc702 JK |
745 | |
746 | static bool bdev_writes_blocked(struct block_device *bdev) | |
747 | { | |
748 | return bdev->bd_writers == -1; | |
749 | } | |
750 | ||
751 | static void bdev_block_writes(struct block_device *bdev) | |
752 | { | |
753 | bdev->bd_writers = -1; | |
754 | } | |
755 | ||
756 | static void bdev_unblock_writes(struct block_device *bdev) | |
757 | { | |
758 | bdev->bd_writers = 0; | |
759 | } | |
760 | ||
761 | static bool bdev_may_open(struct block_device *bdev, blk_mode_t mode) | |
762 | { | |
763 | if (bdev_allow_write_mounted) | |
764 | return true; | |
765 | /* Writes blocked? */ | |
766 | if (mode & BLK_OPEN_WRITE && bdev_writes_blocked(bdev)) | |
767 | return false; | |
768 | if (mode & BLK_OPEN_RESTRICT_WRITES && bdev->bd_writers > 0) | |
769 | return false; | |
770 | return true; | |
771 | } | |
772 | ||
773 | static void bdev_claim_write_access(struct block_device *bdev, blk_mode_t mode) | |
774 | { | |
775 | if (bdev_allow_write_mounted) | |
776 | return; | |
777 | ||
778 | /* Claim exclusive or shared write access. */ | |
779 | if (mode & BLK_OPEN_RESTRICT_WRITES) | |
780 | bdev_block_writes(bdev); | |
781 | else if (mode & BLK_OPEN_WRITE) | |
782 | bdev->bd_writers++; | |
783 | } | |
784 | ||
785 | static void bdev_yield_write_access(struct block_device *bdev, blk_mode_t mode) | |
786 | { | |
787 | if (bdev_allow_write_mounted) | |
788 | return; | |
789 | ||
790 | /* Yield exclusive or shared write access. */ | |
791 | if (mode & BLK_OPEN_RESTRICT_WRITES) | |
792 | bdev_unblock_writes(bdev); | |
793 | else if (mode & BLK_OPEN_WRITE) | |
794 | bdev->bd_writers--; | |
795 | } | |
796 | ||
d4d77629 | 797 | /** |
cd34758c | 798 | * bdev_open_by_dev - open a block device by device number |
4e7b5671 | 799 | * @dev: device number of block device to open |
05bdb996 | 800 | * @mode: open mode (BLK_OPEN_*) |
d4d77629 | 801 | * @holder: exclusive holder identifier |
0718afd4 | 802 | * @hops: holder operations |
d4d77629 | 803 | * |
2736e8ee CH |
804 | * Open the block device described by device number @dev. If @holder is not |
805 | * %NULL, the block device is opened with exclusive access. Exclusive opens may | |
806 | * nest for the same @holder. | |
d4d77629 | 807 | * |
4e7b5671 CH |
808 | * Use this interface ONLY if you really do not have anything better - i.e. when |
809 | * you are behind a truly sucky interface and all you are given is a device | |
cd34758c | 810 | * number. Everything else should use bdev_open_by_path(). |
d4d77629 TH |
811 | * |
812 | * CONTEXT: | |
813 | * Might sleep. | |
814 | * | |
815 | * RETURNS: | |
cd34758c JK |
816 | * Handle with a reference to the block_device on success, ERR_PTR(-errno) on |
817 | * failure. | |
d4d77629 | 818 | */ |
cd34758c JK |
819 | struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder, |
820 | const struct blk_holder_ops *hops) | |
1da177e4 | 821 | { |
cd34758c JK |
822 | struct bdev_handle *handle = kmalloc(sizeof(struct bdev_handle), |
823 | GFP_KERNEL); | |
4e7b5671 | 824 | struct block_device *bdev; |
cd34758c | 825 | bool unblock_events = true; |
5b56b6ed | 826 | struct gendisk *disk; |
5b56b6ed | 827 | int ret; |
e525fd89 | 828 | |
cd34758c JK |
829 | if (!handle) |
830 | return ERR_PTR(-ENOMEM); | |
831 | ||
7918f0f6 | 832 | ret = devcgroup_check_permission(DEVCG_DEV_BLOCK, |
4e7b5671 | 833 | MAJOR(dev), MINOR(dev), |
05bdb996 CH |
834 | ((mode & BLK_OPEN_READ) ? DEVCG_ACC_READ : 0) | |
835 | ((mode & BLK_OPEN_WRITE) ? DEVCG_ACC_WRITE : 0)); | |
e5c7fb40 | 836 | if (ret) |
cd34758c | 837 | goto free_handle; |
4e7b5671 | 838 | |
ed5cc702 | 839 | /* Blocking writes requires exclusive opener */ |
8ff363ad CJ |
840 | if (mode & BLK_OPEN_RESTRICT_WRITES && !holder) { |
841 | ret = -EINVAL; | |
842 | goto free_handle; | |
843 | } | |
4e7b5671 | 844 | |
22ae8ce8 | 845 | bdev = blkdev_get_no_open(dev); |
cd34758c JK |
846 | if (!bdev) { |
847 | ret = -ENXIO; | |
848 | goto free_handle; | |
849 | } | |
22ae8ce8 | 850 | disk = bdev->bd_disk; |
e5c7fb40 | 851 | |
2736e8ee | 852 | if (holder) { |
05bdb996 | 853 | mode |= BLK_OPEN_EXCL; |
0718afd4 | 854 | ret = bd_prepare_to_claim(bdev, holder, hops); |
5b56b6ed | 855 | if (ret) |
37c3fc9a | 856 | goto put_blkdev; |
2736e8ee | 857 | } else { |
05bdb996 | 858 | if (WARN_ON_ONCE(mode & BLK_OPEN_EXCL)) { |
2736e8ee CH |
859 | ret = -EIO; |
860 | goto put_blkdev; | |
861 | } | |
5b56b6ed CH |
862 | } |
863 | ||
864 | disk_block_events(disk); | |
865 | ||
a8698707 | 866 | mutex_lock(&disk->open_mutex); |
362529d9 | 867 | ret = -ENXIO; |
50b4aecf | 868 | if (!disk_live(disk)) |
362529d9 | 869 | goto abort_claiming; |
efcf5932 ML |
870 | if (!try_module_get(disk->fops->owner)) |
871 | goto abort_claiming; | |
ed5cc702 JK |
872 | ret = -EBUSY; |
873 | if (!bdev_may_open(bdev, mode)) | |
874 | goto abort_claiming; | |
362529d9 CH |
875 | if (bdev_is_partition(bdev)) |
876 | ret = blkdev_get_part(bdev, mode); | |
877 | else | |
878 | ret = blkdev_get_whole(bdev, mode); | |
22ae8ce8 | 879 | if (ret) |
efcf5932 | 880 | goto put_module; |
ed5cc702 | 881 | bdev_claim_write_access(bdev, mode); |
2736e8ee | 882 | if (holder) { |
0718afd4 | 883 | bd_finish_claiming(bdev, holder, hops); |
5b56b6ed CH |
884 | |
885 | /* | |
886 | * Block event polling for write claims if requested. Any write | |
887 | * holder makes the write_holder state stick until all are | |
888 | * released. This is good enough and tracking individual | |
889 | * writeable reference is too fragile given the way @mode is | |
890 | * used in blkdev_get/put(). | |
891 | */ | |
05bdb996 | 892 | if ((mode & BLK_OPEN_WRITE) && !bdev->bd_write_holder && |
1545e0b4 | 893 | (disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) { |
5b56b6ed CH |
894 | bdev->bd_write_holder = true; |
895 | unblock_events = false; | |
896 | } | |
897 | } | |
a8698707 | 898 | mutex_unlock(&disk->open_mutex); |
5b56b6ed CH |
899 | |
900 | if (unblock_events) | |
901 | disk_unblock_events(disk); | |
cd34758c JK |
902 | handle->bdev = bdev; |
903 | handle->holder = holder; | |
904 | handle->mode = mode; | |
905 | return handle; | |
efcf5932 ML |
906 | put_module: |
907 | module_put(disk->fops->owner); | |
22ae8ce8 | 908 | abort_claiming: |
2736e8ee | 909 | if (holder) |
37c3fc9a | 910 | bd_abort_claiming(bdev, holder); |
a8698707 | 911 | mutex_unlock(&disk->open_mutex); |
22ae8ce8 | 912 | disk_unblock_events(disk); |
22ae8ce8 CH |
913 | put_blkdev: |
914 | blkdev_put_no_open(bdev); | |
cd34758c JK |
915 | free_handle: |
916 | kfree(handle); | |
22ae8ce8 | 917 | return ERR_PTR(ret); |
37be4124 | 918 | } |
e719b4d1 | 919 | |
f3a60882 CB |
920 | /* |
921 | * If BLK_OPEN_WRITE_IOCTL is set then this is a historical quirk | |
922 | * associated with the floppy driver where it has allowed ioctls if the | |
923 | * file was opened for writing, but does not allow reads or writes. | |
924 | * Make sure that this quirk is reflected in @f_flags. | |
925 | * | |
926 | * It can also happen if a block device is opened as O_RDWR | O_WRONLY. | |
927 | */ | |
928 | static unsigned blk_to_file_flags(blk_mode_t mode) | |
929 | { | |
930 | unsigned int flags = 0; | |
931 | ||
932 | if ((mode & (BLK_OPEN_READ | BLK_OPEN_WRITE)) == | |
933 | (BLK_OPEN_READ | BLK_OPEN_WRITE)) | |
934 | flags |= O_RDWR; | |
935 | else if (mode & BLK_OPEN_WRITE_IOCTL) | |
936 | flags |= O_RDWR | O_WRONLY; | |
937 | else if (mode & BLK_OPEN_WRITE) | |
938 | flags |= O_WRONLY; | |
939 | else if (mode & BLK_OPEN_READ) | |
940 | flags |= O_RDONLY; /* homeopathic, because O_RDONLY is 0 */ | |
941 | else | |
942 | WARN_ON_ONCE(true); | |
943 | ||
944 | if (mode & BLK_OPEN_NDELAY) | |
945 | flags |= O_NDELAY; | |
946 | ||
947 | return flags; | |
948 | } | |
949 | ||
950 | struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder, | |
951 | const struct blk_holder_ops *hops) | |
952 | { | |
953 | struct file *bdev_file; | |
954 | struct bdev_handle *handle; | |
955 | unsigned int flags; | |
956 | ||
957 | handle = bdev_open_by_dev(dev, mode, holder, hops); | |
958 | if (IS_ERR(handle)) | |
959 | return ERR_CAST(handle); | |
960 | ||
961 | flags = blk_to_file_flags(mode); | |
962 | bdev_file = alloc_file_pseudo_noaccount(handle->bdev->bd_inode, | |
963 | blockdev_mnt, "", flags | O_LARGEFILE, &def_blk_fops); | |
964 | if (IS_ERR(bdev_file)) { | |
965 | bdev_release(handle); | |
966 | return bdev_file; | |
967 | } | |
968 | ihold(handle->bdev->bd_inode); | |
969 | ||
970 | bdev_file->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT; | |
971 | if (bdev_nowait(handle->bdev)) | |
972 | bdev_file->f_mode |= FMODE_NOWAIT; | |
973 | ||
974 | bdev_file->f_mapping = handle->bdev->bd_inode->i_mapping; | |
975 | bdev_file->f_wb_err = filemap_sample_wb_err(bdev_file->f_mapping); | |
976 | bdev_file->private_data = handle; | |
977 | return bdev_file; | |
978 | } | |
979 | EXPORT_SYMBOL(bdev_file_open_by_dev); | |
980 | ||
981 | struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode, | |
982 | void *holder, | |
983 | const struct blk_holder_ops *hops) | |
984 | { | |
985 | struct file *bdev_file; | |
986 | dev_t dev; | |
987 | int error; | |
988 | ||
989 | error = lookup_bdev(path, &dev); | |
990 | if (error) | |
991 | return ERR_PTR(error); | |
992 | ||
993 | bdev_file = bdev_file_open_by_dev(dev, mode, holder, hops); | |
994 | if (!IS_ERR(bdev_file) && (mode & BLK_OPEN_WRITE)) { | |
995 | struct bdev_handle *handle = bdev_file->private_data; | |
996 | if (bdev_read_only(handle->bdev)) { | |
997 | fput(bdev_file); | |
998 | bdev_file = ERR_PTR(-EACCES); | |
999 | } | |
1000 | } | |
1001 | ||
1002 | return bdev_file; | |
1003 | } | |
1004 | EXPORT_SYMBOL(bdev_file_open_by_path); | |
1005 | ||
cd34758c | 1006 | void bdev_release(struct bdev_handle *handle) |
2e7b651d | 1007 | { |
cd34758c | 1008 | struct block_device *bdev = handle->bdev; |
2e7b651d PZ |
1009 | struct gendisk *disk = bdev->bd_disk; |
1010 | ||
b849dd84 DA |
1011 | /* |
1012 | * Sync early if it looks like we're the last one. If someone else | |
1013 | * opens the block device between now and the decrement of bd_openers | |
1014 | * then we did a sync that we didn't need to, but that's not the end | |
1015 | * of the world and we want to avoid long (could be several minute) | |
1016 | * syncs while holding the mutex. | |
1017 | */ | |
9acf381f | 1018 | if (atomic_read(&bdev->bd_openers) == 1) |
b849dd84 DA |
1019 | sync_blockdev(bdev); |
1020 | ||
a8698707 | 1021 | mutex_lock(&disk->open_mutex); |
ed5cc702 JK |
1022 | bdev_yield_write_access(bdev, handle->mode); |
1023 | ||
cd34758c JK |
1024 | if (handle->holder) |
1025 | bd_end_claim(bdev, handle->holder); | |
77ea887e | 1026 | |
85ef06d1 TH |
1027 | /* |
1028 | * Trigger event checking and tell drivers to flush MEDIA_CHANGE | |
1029 | * event. This is to ensure detection of media removal commanded | |
1030 | * from userland - e.g. eject(1). | |
1031 | */ | |
5b56b6ed | 1032 | disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); |
85ef06d1 | 1033 | |
c8276b95 | 1034 | if (bdev_is_partition(bdev)) |
ae220766 | 1035 | blkdev_put_part(bdev); |
c8276b95 | 1036 | else |
ae220766 | 1037 | blkdev_put_whole(bdev); |
a8698707 CH |
1038 | mutex_unlock(&disk->open_mutex); |
1039 | ||
efcf5932 | 1040 | module_put(disk->fops->owner); |
22ae8ce8 | 1041 | blkdev_put_no_open(bdev); |
e719b4d1 JK |
1042 | kfree(handle); |
1043 | } | |
e719b4d1 | 1044 | |
1da177e4 | 1045 | /** |
0ba4566c MWO |
1046 | * lookup_bdev() - Look up a struct block_device by name. |
1047 | * @pathname: Name of the block device in the filesystem. | |
1048 | * @dev: Pointer to the block device's dev_t, if found. | |
1da177e4 | 1049 | * |
057178cf | 1050 | * Lookup the block device's dev_t at @pathname in the current |
0ba4566c | 1051 | * namespace if possible and return it in @dev. |
057178cf | 1052 | * |
0ba4566c MWO |
1053 | * Context: May sleep. |
1054 | * Return: 0 if succeeded, negative errno otherwise. | |
1da177e4 | 1055 | */ |
4e7b5671 | 1056 | int lookup_bdev(const char *pathname, dev_t *dev) |
1da177e4 | 1057 | { |
1da177e4 | 1058 | struct inode *inode; |
421748ec | 1059 | struct path path; |
1da177e4 LT |
1060 | int error; |
1061 | ||
421748ec | 1062 | if (!pathname || !*pathname) |
4e7b5671 | 1063 | return -EINVAL; |
1da177e4 | 1064 | |
421748ec | 1065 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
1da177e4 | 1066 | if (error) |
4e7b5671 | 1067 | return error; |
1da177e4 | 1068 | |
bb668734 | 1069 | inode = d_backing_inode(path.dentry); |
1da177e4 LT |
1070 | error = -ENOTBLK; |
1071 | if (!S_ISBLK(inode->i_mode)) | |
4e7b5671 | 1072 | goto out_path_put; |
1da177e4 | 1073 | error = -EACCES; |
a2982cc9 | 1074 | if (!may_open_dev(&path)) |
4e7b5671 CH |
1075 | goto out_path_put; |
1076 | ||
1077 | *dev = inode->i_rdev; | |
1078 | error = 0; | |
1079 | out_path_put: | |
421748ec | 1080 | path_put(&path); |
4e7b5671 | 1081 | return error; |
1da177e4 | 1082 | } |
d5686b44 | 1083 | EXPORT_SYMBOL(lookup_bdev); |
1da177e4 | 1084 | |
560e20e4 CH |
1085 | /** |
1086 | * bdev_mark_dead - mark a block device as dead | |
1087 | * @bdev: block device to operate on | |
1088 | * @surprise: indicate a surprise removal | |
1089 | * | |
1090 | * Tell the file system that this devices or media is dead. If @surprise is set | |
1091 | * to %true the device or media is already gone, if not we are preparing for an | |
1092 | * orderly removal. | |
1093 | * | |
d8530de5 CH |
1094 | * This calls into the file system, which then typicall syncs out all dirty data |
1095 | * and writes back inodes and then invalidates any cached data in the inodes on | |
1096 | * the file system. In addition we also invalidate the block device mapping. | |
560e20e4 CH |
1097 | */ |
1098 | void bdev_mark_dead(struct block_device *bdev, bool surprise) | |
b71e8a4c | 1099 | { |
d8530de5 CH |
1100 | mutex_lock(&bdev->bd_holder_lock); |
1101 | if (bdev->bd_holder_ops && bdev->bd_holder_ops->mark_dead) | |
1102 | bdev->bd_holder_ops->mark_dead(bdev, surprise); | |
fd146410 JK |
1103 | else { |
1104 | mutex_unlock(&bdev->bd_holder_lock); | |
d8530de5 | 1105 | sync_blockdev(bdev); |
fd146410 | 1106 | } |
b71e8a4c | 1107 | |
f98393a6 | 1108 | invalidate_bdev(bdev); |
b71e8a4c | 1109 | } |
560e20e4 | 1110 | /* |
6e57236e CH |
1111 | * New drivers should not use this directly. There are some drivers however |
1112 | * that needs this for historical reasons. For example, the DASD driver has | |
1113 | * historically had a shutdown to offline mode that doesn't actually remove the | |
1114 | * gendisk that otherwise looks a lot like a safe device removal. | |
560e20e4 CH |
1115 | */ |
1116 | EXPORT_SYMBOL_GPL(bdev_mark_dead); | |
5c0d6b60 | 1117 | |
1e03a36b | 1118 | void sync_bdevs(bool wait) |
5c0d6b60 JK |
1119 | { |
1120 | struct inode *inode, *old_inode = NULL; | |
1121 | ||
74278da9 | 1122 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1123 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { |
1124 | struct address_space *mapping = inode->i_mapping; | |
af309226 | 1125 | struct block_device *bdev; |
5c0d6b60 JK |
1126 | |
1127 | spin_lock(&inode->i_lock); | |
1128 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || | |
1129 | mapping->nrpages == 0) { | |
1130 | spin_unlock(&inode->i_lock); | |
1131 | continue; | |
1132 | } | |
1133 | __iget(inode); | |
1134 | spin_unlock(&inode->i_lock); | |
74278da9 | 1135 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1136 | /* |
1137 | * We hold a reference to 'inode' so it couldn't have been | |
1138 | * removed from s_inodes list while we dropped the | |
74278da9 | 1139 | * s_inode_list_lock We cannot iput the inode now as we can |
5c0d6b60 | 1140 | * be holding the last reference and we cannot iput it under |
74278da9 | 1141 | * s_inode_list_lock. So we keep the reference and iput it |
5c0d6b60 JK |
1142 | * later. |
1143 | */ | |
1144 | iput(old_inode); | |
1145 | old_inode = inode; | |
af309226 | 1146 | bdev = I_BDEV(inode); |
5c0d6b60 | 1147 | |
a8698707 | 1148 | mutex_lock(&bdev->bd_disk->open_mutex); |
9acf381f | 1149 | if (!atomic_read(&bdev->bd_openers)) { |
1e03a36b CH |
1150 | ; /* skip */ |
1151 | } else if (wait) { | |
1152 | /* | |
1153 | * We keep the error status of individual mapping so | |
1154 | * that applications can catch the writeback error using | |
1155 | * fsync(2). See filemap_fdatawait_keep_errors() for | |
1156 | * details. | |
1157 | */ | |
1158 | filemap_fdatawait_keep_errors(inode->i_mapping); | |
1159 | } else { | |
1160 | filemap_fdatawrite(inode->i_mapping); | |
1161 | } | |
a8698707 | 1162 | mutex_unlock(&bdev->bd_disk->open_mutex); |
5c0d6b60 | 1163 | |
74278da9 | 1164 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 | 1165 | } |
74278da9 | 1166 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1167 | iput(old_inode); |
1168 | } | |
2d985f8c EB |
1169 | |
1170 | /* | |
1171 | * Handle STATX_DIOALIGN for block devices. | |
1172 | * | |
1173 | * Note that the inode passed to this is the inode of a block device node file, | |
1174 | * not the block device's internal inode. Therefore it is *not* valid to use | |
1175 | * I_BDEV() here; the block device has to be looked up by i_rdev instead. | |
1176 | */ | |
1177 | void bdev_statx_dioalign(struct inode *inode, struct kstat *stat) | |
1178 | { | |
1179 | struct block_device *bdev; | |
1180 | ||
1181 | bdev = blkdev_get_no_open(inode->i_rdev); | |
1182 | if (!bdev) | |
1183 | return; | |
1184 | ||
1185 | stat->dio_mem_align = bdev_dma_alignment(bdev) + 1; | |
1186 | stat->dio_offset_align = bdev_logical_block_size(bdev); | |
1187 | stat->result_mask |= STATX_DIOALIGN; | |
1188 | ||
1189 | blkdev_put_no_open(bdev); | |
1190 | } | |
ed5cc702 JK |
1191 | |
1192 | static int __init setup_bdev_allow_write_mounted(char *str) | |
1193 | { | |
1194 | if (kstrtobool(str, &bdev_allow_write_mounted)) | |
1195 | pr_warn("Invalid option string for bdev_allow_write_mounted:" | |
1196 | " '%s'\n", str); | |
1197 | return 1; | |
1198 | } | |
1199 | __setup("bdev_allow_write_mounted=", setup_bdev_allow_write_mounted); |