Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/block_dev.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE | |
6 | */ | |
7 | ||
8 | #include <linux/config.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/mm.h> | |
11 | #include <linux/fcntl.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/kmod.h> | |
14 | #include <linux/major.h> | |
15 | #include <linux/devfs_fs_kernel.h> | |
16 | #include <linux/smp_lock.h> | |
17 | #include <linux/highmem.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/blkpg.h> | |
21 | #include <linux/buffer_head.h> | |
22 | #include <linux/mpage.h> | |
23 | #include <linux/mount.h> | |
24 | #include <linux/uio.h> | |
25 | #include <linux/namei.h> | |
26 | #include <asm/uaccess.h> | |
27 | ||
28 | struct bdev_inode { | |
29 | struct block_device bdev; | |
30 | struct inode vfs_inode; | |
31 | }; | |
32 | ||
33 | static inline struct bdev_inode *BDEV_I(struct inode *inode) | |
34 | { | |
35 | return container_of(inode, struct bdev_inode, vfs_inode); | |
36 | } | |
37 | ||
38 | inline struct block_device *I_BDEV(struct inode *inode) | |
39 | { | |
40 | return &BDEV_I(inode)->bdev; | |
41 | } | |
42 | ||
43 | EXPORT_SYMBOL(I_BDEV); | |
44 | ||
45 | static sector_t max_block(struct block_device *bdev) | |
46 | { | |
47 | sector_t retval = ~((sector_t)0); | |
48 | loff_t sz = i_size_read(bdev->bd_inode); | |
49 | ||
50 | if (sz) { | |
51 | unsigned int size = block_size(bdev); | |
52 | unsigned int sizebits = blksize_bits(size); | |
53 | retval = (sz >> sizebits); | |
54 | } | |
55 | return retval; | |
56 | } | |
57 | ||
58 | /* Kill _all_ buffers, dirty or not.. */ | |
59 | static void kill_bdev(struct block_device *bdev) | |
60 | { | |
61 | invalidate_bdev(bdev, 1); | |
62 | truncate_inode_pages(bdev->bd_inode->i_mapping, 0); | |
63 | } | |
64 | ||
65 | int set_blocksize(struct block_device *bdev, int size) | |
66 | { | |
67 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
68 | if (size > PAGE_SIZE || size < 512 || (size & (size-1))) | |
69 | return -EINVAL; | |
70 | ||
71 | /* Size cannot be smaller than the size supported by the device */ | |
72 | if (size < bdev_hardsect_size(bdev)) | |
73 | return -EINVAL; | |
74 | ||
75 | /* Don't change the size if it is same as current */ | |
76 | if (bdev->bd_block_size != size) { | |
77 | sync_blockdev(bdev); | |
78 | bdev->bd_block_size = size; | |
79 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
80 | kill_bdev(bdev); | |
81 | } | |
82 | return 0; | |
83 | } | |
84 | ||
85 | EXPORT_SYMBOL(set_blocksize); | |
86 | ||
87 | int sb_set_blocksize(struct super_block *sb, int size) | |
88 | { | |
89 | int bits = 9; /* 2^9 = 512 */ | |
90 | ||
91 | if (set_blocksize(sb->s_bdev, size)) | |
92 | return 0; | |
93 | /* If we get here, we know size is power of two | |
94 | * and it's value is between 512 and PAGE_SIZE */ | |
95 | sb->s_blocksize = size; | |
96 | for (size >>= 10; size; size >>= 1) | |
97 | ++bits; | |
98 | sb->s_blocksize_bits = bits; | |
99 | return sb->s_blocksize; | |
100 | } | |
101 | ||
102 | EXPORT_SYMBOL(sb_set_blocksize); | |
103 | ||
104 | int sb_min_blocksize(struct super_block *sb, int size) | |
105 | { | |
106 | int minsize = bdev_hardsect_size(sb->s_bdev); | |
107 | if (size < minsize) | |
108 | size = minsize; | |
109 | return sb_set_blocksize(sb, size); | |
110 | } | |
111 | ||
112 | EXPORT_SYMBOL(sb_min_blocksize); | |
113 | ||
114 | static int | |
115 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
116 | struct buffer_head *bh, int create) | |
117 | { | |
118 | if (iblock >= max_block(I_BDEV(inode))) { | |
119 | if (create) | |
120 | return -EIO; | |
121 | ||
122 | /* | |
123 | * for reads, we're just trying to fill a partial page. | |
124 | * return a hole, they will have to call get_block again | |
125 | * before they can fill it, and they will get -EIO at that | |
126 | * time | |
127 | */ | |
128 | return 0; | |
129 | } | |
130 | bh->b_bdev = I_BDEV(inode); | |
131 | bh->b_blocknr = iblock; | |
132 | set_buffer_mapped(bh); | |
133 | return 0; | |
134 | } | |
135 | ||
136 | static int | |
137 | blkdev_get_blocks(struct inode *inode, sector_t iblock, | |
138 | unsigned long max_blocks, struct buffer_head *bh, int create) | |
139 | { | |
140 | sector_t end_block = max_block(I_BDEV(inode)); | |
141 | ||
142 | if ((iblock + max_blocks) > end_block) { | |
143 | max_blocks = end_block - iblock; | |
144 | if ((long)max_blocks <= 0) { | |
145 | if (create) | |
146 | return -EIO; /* write fully beyond EOF */ | |
147 | /* | |
148 | * It is a read which is fully beyond EOF. We return | |
149 | * a !buffer_mapped buffer | |
150 | */ | |
151 | max_blocks = 0; | |
152 | } | |
153 | } | |
154 | ||
155 | bh->b_bdev = I_BDEV(inode); | |
156 | bh->b_blocknr = iblock; | |
157 | bh->b_size = max_blocks << inode->i_blkbits; | |
158 | if (max_blocks) | |
159 | set_buffer_mapped(bh); | |
160 | return 0; | |
161 | } | |
162 | ||
163 | static ssize_t | |
164 | blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, | |
165 | loff_t offset, unsigned long nr_segs) | |
166 | { | |
167 | struct file *file = iocb->ki_filp; | |
168 | struct inode *inode = file->f_mapping->host; | |
169 | ||
170 | return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode), | |
171 | iov, offset, nr_segs, blkdev_get_blocks, NULL); | |
172 | } | |
173 | ||
174 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) | |
175 | { | |
176 | return block_write_full_page(page, blkdev_get_block, wbc); | |
177 | } | |
178 | ||
179 | static int blkdev_readpage(struct file * file, struct page * page) | |
180 | { | |
181 | return block_read_full_page(page, blkdev_get_block); | |
182 | } | |
183 | ||
184 | static int blkdev_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) | |
185 | { | |
186 | return block_prepare_write(page, from, to, blkdev_get_block); | |
187 | } | |
188 | ||
189 | static int blkdev_commit_write(struct file *file, struct page *page, unsigned from, unsigned to) | |
190 | { | |
191 | return block_commit_write(page, from, to); | |
192 | } | |
193 | ||
194 | /* | |
195 | * private llseek: | |
196 | * for a block special file file->f_dentry->d_inode->i_size is zero | |
197 | * so we compute the size by hand (just as in block_read/write above) | |
198 | */ | |
199 | static loff_t block_llseek(struct file *file, loff_t offset, int origin) | |
200 | { | |
201 | struct inode *bd_inode = file->f_mapping->host; | |
202 | loff_t size; | |
203 | loff_t retval; | |
204 | ||
1b1dcc1b | 205 | mutex_lock(&bd_inode->i_mutex); |
1da177e4 LT |
206 | size = i_size_read(bd_inode); |
207 | ||
208 | switch (origin) { | |
209 | case 2: | |
210 | offset += size; | |
211 | break; | |
212 | case 1: | |
213 | offset += file->f_pos; | |
214 | } | |
215 | retval = -EINVAL; | |
216 | if (offset >= 0 && offset <= size) { | |
217 | if (offset != file->f_pos) { | |
218 | file->f_pos = offset; | |
219 | } | |
220 | retval = offset; | |
221 | } | |
1b1dcc1b | 222 | mutex_unlock(&bd_inode->i_mutex); |
1da177e4 LT |
223 | return retval; |
224 | } | |
225 | ||
226 | /* | |
227 | * Filp is never NULL; the only case when ->fsync() is called with | |
228 | * NULL first argument is nfsd_sync_dir() and that's not a directory. | |
229 | */ | |
230 | ||
231 | static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) | |
232 | { | |
233 | return sync_blockdev(I_BDEV(filp->f_mapping->host)); | |
234 | } | |
235 | ||
236 | /* | |
237 | * pseudo-fs | |
238 | */ | |
239 | ||
240 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
241 | static kmem_cache_t * bdev_cachep; | |
242 | ||
243 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
244 | { | |
245 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL); | |
246 | if (!ei) | |
247 | return NULL; | |
248 | return &ei->vfs_inode; | |
249 | } | |
250 | ||
251 | static void bdev_destroy_inode(struct inode *inode) | |
252 | { | |
253 | struct bdev_inode *bdi = BDEV_I(inode); | |
254 | ||
255 | bdi->bdev.bd_inode_backing_dev_info = NULL; | |
256 | kmem_cache_free(bdev_cachep, bdi); | |
257 | } | |
258 | ||
259 | static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) | |
260 | { | |
261 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
262 | struct block_device *bdev = &ei->bdev; | |
263 | ||
264 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == | |
265 | SLAB_CTOR_CONSTRUCTOR) | |
266 | { | |
267 | memset(bdev, 0, sizeof(*bdev)); | |
c039e313 AV |
268 | mutex_init(&bdev->bd_mutex); |
269 | mutex_init(&bdev->bd_mount_mutex); | |
1da177e4 LT |
270 | INIT_LIST_HEAD(&bdev->bd_inodes); |
271 | INIT_LIST_HEAD(&bdev->bd_list); | |
272 | inode_init_once(&ei->vfs_inode); | |
273 | } | |
274 | } | |
275 | ||
276 | static inline void __bd_forget(struct inode *inode) | |
277 | { | |
278 | list_del_init(&inode->i_devices); | |
279 | inode->i_bdev = NULL; | |
280 | inode->i_mapping = &inode->i_data; | |
281 | } | |
282 | ||
283 | static void bdev_clear_inode(struct inode *inode) | |
284 | { | |
285 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
286 | struct list_head *p; | |
287 | spin_lock(&bdev_lock); | |
288 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { | |
289 | __bd_forget(list_entry(p, struct inode, i_devices)); | |
290 | } | |
291 | list_del_init(&bdev->bd_list); | |
292 | spin_unlock(&bdev_lock); | |
293 | } | |
294 | ||
295 | static struct super_operations bdev_sops = { | |
296 | .statfs = simple_statfs, | |
297 | .alloc_inode = bdev_alloc_inode, | |
298 | .destroy_inode = bdev_destroy_inode, | |
299 | .drop_inode = generic_delete_inode, | |
300 | .clear_inode = bdev_clear_inode, | |
301 | }; | |
302 | ||
303 | static struct super_block *bd_get_sb(struct file_system_type *fs_type, | |
304 | int flags, const char *dev_name, void *data) | |
305 | { | |
306 | return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576); | |
307 | } | |
308 | ||
309 | static struct file_system_type bd_type = { | |
310 | .name = "bdev", | |
311 | .get_sb = bd_get_sb, | |
312 | .kill_sb = kill_anon_super, | |
313 | }; | |
314 | ||
315 | static struct vfsmount *bd_mnt; | |
316 | struct super_block *blockdev_superblock; | |
317 | ||
318 | void __init bdev_cache_init(void) | |
319 | { | |
320 | int err; | |
321 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), | |
fffb60f9 PJ |
322 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
323 | SLAB_MEM_SPREAD|SLAB_PANIC), | |
1da177e4 LT |
324 | init_once, NULL); |
325 | err = register_filesystem(&bd_type); | |
326 | if (err) | |
327 | panic("Cannot register bdev pseudo-fs"); | |
328 | bd_mnt = kern_mount(&bd_type); | |
329 | err = PTR_ERR(bd_mnt); | |
330 | if (IS_ERR(bd_mnt)) | |
331 | panic("Cannot create bdev pseudo-fs"); | |
332 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ | |
333 | } | |
334 | ||
335 | /* | |
336 | * Most likely _very_ bad one - but then it's hardly critical for small | |
337 | * /dev and can be fixed when somebody will need really large one. | |
338 | * Keep in mind that it will be fed through icache hash function too. | |
339 | */ | |
340 | static inline unsigned long hash(dev_t dev) | |
341 | { | |
342 | return MAJOR(dev)+MINOR(dev); | |
343 | } | |
344 | ||
345 | static int bdev_test(struct inode *inode, void *data) | |
346 | { | |
347 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
348 | } | |
349 | ||
350 | static int bdev_set(struct inode *inode, void *data) | |
351 | { | |
352 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
353 | return 0; | |
354 | } | |
355 | ||
356 | static LIST_HEAD(all_bdevs); | |
357 | ||
358 | struct block_device *bdget(dev_t dev) | |
359 | { | |
360 | struct block_device *bdev; | |
361 | struct inode *inode; | |
362 | ||
363 | inode = iget5_locked(bd_mnt->mnt_sb, hash(dev), | |
364 | bdev_test, bdev_set, &dev); | |
365 | ||
366 | if (!inode) | |
367 | return NULL; | |
368 | ||
369 | bdev = &BDEV_I(inode)->bdev; | |
370 | ||
371 | if (inode->i_state & I_NEW) { | |
372 | bdev->bd_contains = NULL; | |
373 | bdev->bd_inode = inode; | |
374 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
375 | bdev->bd_part_count = 0; | |
376 | bdev->bd_invalidated = 0; | |
377 | inode->i_mode = S_IFBLK; | |
378 | inode->i_rdev = dev; | |
379 | inode->i_bdev = bdev; | |
380 | inode->i_data.a_ops = &def_blk_aops; | |
381 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
382 | inode->i_data.backing_dev_info = &default_backing_dev_info; | |
383 | spin_lock(&bdev_lock); | |
384 | list_add(&bdev->bd_list, &all_bdevs); | |
385 | spin_unlock(&bdev_lock); | |
386 | unlock_new_inode(inode); | |
387 | } | |
388 | return bdev; | |
389 | } | |
390 | ||
391 | EXPORT_SYMBOL(bdget); | |
392 | ||
393 | long nr_blockdev_pages(void) | |
394 | { | |
395 | struct list_head *p; | |
396 | long ret = 0; | |
397 | spin_lock(&bdev_lock); | |
398 | list_for_each(p, &all_bdevs) { | |
399 | struct block_device *bdev; | |
400 | bdev = list_entry(p, struct block_device, bd_list); | |
401 | ret += bdev->bd_inode->i_mapping->nrpages; | |
402 | } | |
403 | spin_unlock(&bdev_lock); | |
404 | return ret; | |
405 | } | |
406 | ||
407 | void bdput(struct block_device *bdev) | |
408 | { | |
409 | iput(bdev->bd_inode); | |
410 | } | |
411 | ||
412 | EXPORT_SYMBOL(bdput); | |
413 | ||
414 | static struct block_device *bd_acquire(struct inode *inode) | |
415 | { | |
416 | struct block_device *bdev; | |
417 | spin_lock(&bdev_lock); | |
418 | bdev = inode->i_bdev; | |
419 | if (bdev && igrab(bdev->bd_inode)) { | |
420 | spin_unlock(&bdev_lock); | |
421 | return bdev; | |
422 | } | |
423 | spin_unlock(&bdev_lock); | |
424 | bdev = bdget(inode->i_rdev); | |
425 | if (bdev) { | |
426 | spin_lock(&bdev_lock); | |
427 | if (inode->i_bdev) | |
428 | __bd_forget(inode); | |
429 | inode->i_bdev = bdev; | |
430 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
431 | list_add(&inode->i_devices, &bdev->bd_inodes); | |
432 | spin_unlock(&bdev_lock); | |
433 | } | |
434 | return bdev; | |
435 | } | |
436 | ||
437 | /* Call when you free inode */ | |
438 | ||
439 | void bd_forget(struct inode *inode) | |
440 | { | |
441 | spin_lock(&bdev_lock); | |
442 | if (inode->i_bdev) | |
443 | __bd_forget(inode); | |
444 | spin_unlock(&bdev_lock); | |
445 | } | |
446 | ||
447 | int bd_claim(struct block_device *bdev, void *holder) | |
448 | { | |
449 | int res; | |
450 | spin_lock(&bdev_lock); | |
451 | ||
452 | /* first decide result */ | |
453 | if (bdev->bd_holder == holder) | |
454 | res = 0; /* already a holder */ | |
455 | else if (bdev->bd_holder != NULL) | |
456 | res = -EBUSY; /* held by someone else */ | |
457 | else if (bdev->bd_contains == bdev) | |
458 | res = 0; /* is a whole device which isn't held */ | |
459 | ||
460 | else if (bdev->bd_contains->bd_holder == bd_claim) | |
461 | res = 0; /* is a partition of a device that is being partitioned */ | |
462 | else if (bdev->bd_contains->bd_holder != NULL) | |
463 | res = -EBUSY; /* is a partition of a held device */ | |
464 | else | |
465 | res = 0; /* is a partition of an un-held device */ | |
466 | ||
467 | /* now impose change */ | |
468 | if (res==0) { | |
469 | /* note that for a whole device bd_holders | |
470 | * will be incremented twice, and bd_holder will | |
471 | * be set to bd_claim before being set to holder | |
472 | */ | |
473 | bdev->bd_contains->bd_holders ++; | |
474 | bdev->bd_contains->bd_holder = bd_claim; | |
475 | bdev->bd_holders++; | |
476 | bdev->bd_holder = holder; | |
477 | } | |
478 | spin_unlock(&bdev_lock); | |
479 | return res; | |
480 | } | |
481 | ||
482 | EXPORT_SYMBOL(bd_claim); | |
483 | ||
484 | void bd_release(struct block_device *bdev) | |
485 | { | |
486 | spin_lock(&bdev_lock); | |
487 | if (!--bdev->bd_contains->bd_holders) | |
488 | bdev->bd_contains->bd_holder = NULL; | |
489 | if (!--bdev->bd_holders) | |
490 | bdev->bd_holder = NULL; | |
491 | spin_unlock(&bdev_lock); | |
492 | } | |
493 | ||
494 | EXPORT_SYMBOL(bd_release); | |
495 | ||
496 | /* | |
497 | * Tries to open block device by device number. Use it ONLY if you | |
498 | * really do not have anything better - i.e. when you are behind a | |
499 | * truly sucky interface and all you are given is a device number. _Never_ | |
500 | * to be used for internal purposes. If you ever need it - reconsider | |
501 | * your API. | |
502 | */ | |
503 | struct block_device *open_by_devnum(dev_t dev, unsigned mode) | |
504 | { | |
505 | struct block_device *bdev = bdget(dev); | |
506 | int err = -ENOMEM; | |
507 | int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY; | |
508 | if (bdev) | |
509 | err = blkdev_get(bdev, mode, flags); | |
510 | return err ? ERR_PTR(err) : bdev; | |
511 | } | |
512 | ||
513 | EXPORT_SYMBOL(open_by_devnum); | |
514 | ||
515 | /* | |
516 | * This routine checks whether a removable media has been changed, | |
517 | * and invalidates all buffer-cache-entries in that case. This | |
518 | * is a relatively slow routine, so we have to try to minimize using | |
519 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
520 | * is the best way of combining speed and utility, I think. | |
521 | * People changing diskettes in the middle of an operation deserve | |
522 | * to lose :-) | |
523 | */ | |
524 | int check_disk_change(struct block_device *bdev) | |
525 | { | |
526 | struct gendisk *disk = bdev->bd_disk; | |
527 | struct block_device_operations * bdops = disk->fops; | |
528 | ||
529 | if (!bdops->media_changed) | |
530 | return 0; | |
531 | if (!bdops->media_changed(bdev->bd_disk)) | |
532 | return 0; | |
533 | ||
2ef41634 | 534 | if (__invalidate_device(bdev)) |
1da177e4 LT |
535 | printk("VFS: busy inodes on changed media.\n"); |
536 | ||
537 | if (bdops->revalidate_disk) | |
538 | bdops->revalidate_disk(bdev->bd_disk); | |
539 | if (bdev->bd_disk->minors > 1) | |
540 | bdev->bd_invalidated = 1; | |
541 | return 1; | |
542 | } | |
543 | ||
544 | EXPORT_SYMBOL(check_disk_change); | |
545 | ||
546 | void bd_set_size(struct block_device *bdev, loff_t size) | |
547 | { | |
548 | unsigned bsize = bdev_hardsect_size(bdev); | |
549 | ||
550 | bdev->bd_inode->i_size = size; | |
551 | while (bsize < PAGE_CACHE_SIZE) { | |
552 | if (size & bsize) | |
553 | break; | |
554 | bsize <<= 1; | |
555 | } | |
556 | bdev->bd_block_size = bsize; | |
557 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
558 | } | |
559 | EXPORT_SYMBOL(bd_set_size); | |
560 | ||
561 | static int do_open(struct block_device *bdev, struct file *file) | |
562 | { | |
563 | struct module *owner = NULL; | |
564 | struct gendisk *disk; | |
565 | int ret = -ENXIO; | |
566 | int part; | |
567 | ||
568 | file->f_mapping = bdev->bd_inode->i_mapping; | |
569 | lock_kernel(); | |
570 | disk = get_gendisk(bdev->bd_dev, &part); | |
571 | if (!disk) { | |
572 | unlock_kernel(); | |
573 | bdput(bdev); | |
574 | return ret; | |
575 | } | |
576 | owner = disk->fops->owner; | |
577 | ||
c039e313 | 578 | mutex_lock(&bdev->bd_mutex); |
1da177e4 LT |
579 | if (!bdev->bd_openers) { |
580 | bdev->bd_disk = disk; | |
581 | bdev->bd_contains = bdev; | |
582 | if (!part) { | |
583 | struct backing_dev_info *bdi; | |
584 | if (disk->fops->open) { | |
585 | ret = disk->fops->open(bdev->bd_inode, file); | |
586 | if (ret) | |
587 | goto out_first; | |
588 | } | |
589 | if (!bdev->bd_openers) { | |
590 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); | |
591 | bdi = blk_get_backing_dev_info(bdev); | |
592 | if (bdi == NULL) | |
593 | bdi = &default_backing_dev_info; | |
594 | bdev->bd_inode->i_data.backing_dev_info = bdi; | |
595 | } | |
596 | if (bdev->bd_invalidated) | |
597 | rescan_partitions(disk, bdev); | |
598 | } else { | |
599 | struct hd_struct *p; | |
600 | struct block_device *whole; | |
601 | whole = bdget_disk(disk, 0); | |
602 | ret = -ENOMEM; | |
603 | if (!whole) | |
604 | goto out_first; | |
605 | ret = blkdev_get(whole, file->f_mode, file->f_flags); | |
606 | if (ret) | |
607 | goto out_first; | |
608 | bdev->bd_contains = whole; | |
c039e313 | 609 | mutex_lock(&whole->bd_mutex); |
1da177e4 LT |
610 | whole->bd_part_count++; |
611 | p = disk->part[part - 1]; | |
612 | bdev->bd_inode->i_data.backing_dev_info = | |
613 | whole->bd_inode->i_data.backing_dev_info; | |
614 | if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) { | |
615 | whole->bd_part_count--; | |
c039e313 | 616 | mutex_unlock(&whole->bd_mutex); |
1da177e4 LT |
617 | ret = -ENXIO; |
618 | goto out_first; | |
619 | } | |
620 | kobject_get(&p->kobj); | |
621 | bdev->bd_part = p; | |
622 | bd_set_size(bdev, (loff_t) p->nr_sects << 9); | |
c039e313 | 623 | mutex_unlock(&whole->bd_mutex); |
1da177e4 LT |
624 | } |
625 | } else { | |
626 | put_disk(disk); | |
627 | module_put(owner); | |
628 | if (bdev->bd_contains == bdev) { | |
629 | if (bdev->bd_disk->fops->open) { | |
630 | ret = bdev->bd_disk->fops->open(bdev->bd_inode, file); | |
631 | if (ret) | |
632 | goto out; | |
633 | } | |
634 | if (bdev->bd_invalidated) | |
635 | rescan_partitions(bdev->bd_disk, bdev); | |
636 | } else { | |
c039e313 | 637 | mutex_lock(&bdev->bd_contains->bd_mutex); |
1da177e4 | 638 | bdev->bd_contains->bd_part_count++; |
c039e313 | 639 | mutex_unlock(&bdev->bd_contains->bd_mutex); |
1da177e4 LT |
640 | } |
641 | } | |
642 | bdev->bd_openers++; | |
c039e313 | 643 | mutex_unlock(&bdev->bd_mutex); |
1da177e4 LT |
644 | unlock_kernel(); |
645 | return 0; | |
646 | ||
647 | out_first: | |
648 | bdev->bd_disk = NULL; | |
649 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; | |
650 | if (bdev != bdev->bd_contains) | |
651 | blkdev_put(bdev->bd_contains); | |
652 | bdev->bd_contains = NULL; | |
653 | put_disk(disk); | |
654 | module_put(owner); | |
655 | out: | |
c039e313 | 656 | mutex_unlock(&bdev->bd_mutex); |
1da177e4 LT |
657 | unlock_kernel(); |
658 | if (ret) | |
659 | bdput(bdev); | |
660 | return ret; | |
661 | } | |
662 | ||
663 | int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags) | |
664 | { | |
665 | /* | |
666 | * This crockload is due to bad choice of ->open() type. | |
667 | * It will go away. | |
668 | * For now, block device ->open() routine must _not_ | |
669 | * examine anything in 'inode' argument except ->i_rdev. | |
670 | */ | |
671 | struct file fake_file = {}; | |
672 | struct dentry fake_dentry = {}; | |
673 | fake_file.f_mode = mode; | |
674 | fake_file.f_flags = flags; | |
675 | fake_file.f_dentry = &fake_dentry; | |
676 | fake_dentry.d_inode = bdev->bd_inode; | |
677 | ||
678 | return do_open(bdev, &fake_file); | |
679 | } | |
680 | ||
681 | EXPORT_SYMBOL(blkdev_get); | |
682 | ||
683 | static int blkdev_open(struct inode * inode, struct file * filp) | |
684 | { | |
685 | struct block_device *bdev; | |
686 | int res; | |
687 | ||
688 | /* | |
689 | * Preserve backwards compatibility and allow large file access | |
690 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
691 | * binary needs it. We might want to drop this workaround | |
692 | * during an unstable branch. | |
693 | */ | |
694 | filp->f_flags |= O_LARGEFILE; | |
695 | ||
696 | bdev = bd_acquire(inode); | |
697 | ||
698 | res = do_open(bdev, filp); | |
699 | if (res) | |
700 | return res; | |
701 | ||
702 | if (!(filp->f_flags & O_EXCL) ) | |
703 | return 0; | |
704 | ||
705 | if (!(res = bd_claim(bdev, filp))) | |
706 | return 0; | |
707 | ||
708 | blkdev_put(bdev); | |
709 | return res; | |
710 | } | |
711 | ||
712 | int blkdev_put(struct block_device *bdev) | |
713 | { | |
714 | int ret = 0; | |
715 | struct inode *bd_inode = bdev->bd_inode; | |
716 | struct gendisk *disk = bdev->bd_disk; | |
717 | ||
c039e313 | 718 | mutex_lock(&bdev->bd_mutex); |
1da177e4 LT |
719 | lock_kernel(); |
720 | if (!--bdev->bd_openers) { | |
721 | sync_blockdev(bdev); | |
722 | kill_bdev(bdev); | |
723 | } | |
724 | if (bdev->bd_contains == bdev) { | |
725 | if (disk->fops->release) | |
726 | ret = disk->fops->release(bd_inode, NULL); | |
727 | } else { | |
c039e313 | 728 | mutex_lock(&bdev->bd_contains->bd_mutex); |
1da177e4 | 729 | bdev->bd_contains->bd_part_count--; |
c039e313 | 730 | mutex_unlock(&bdev->bd_contains->bd_mutex); |
1da177e4 LT |
731 | } |
732 | if (!bdev->bd_openers) { | |
733 | struct module *owner = disk->fops->owner; | |
734 | ||
735 | put_disk(disk); | |
736 | module_put(owner); | |
737 | ||
738 | if (bdev->bd_contains != bdev) { | |
739 | kobject_put(&bdev->bd_part->kobj); | |
740 | bdev->bd_part = NULL; | |
741 | } | |
742 | bdev->bd_disk = NULL; | |
743 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; | |
744 | if (bdev != bdev->bd_contains) { | |
745 | blkdev_put(bdev->bd_contains); | |
746 | } | |
747 | bdev->bd_contains = NULL; | |
748 | } | |
749 | unlock_kernel(); | |
c039e313 | 750 | mutex_unlock(&bdev->bd_mutex); |
1da177e4 LT |
751 | bdput(bdev); |
752 | return ret; | |
753 | } | |
754 | ||
755 | EXPORT_SYMBOL(blkdev_put); | |
756 | ||
757 | static int blkdev_close(struct inode * inode, struct file * filp) | |
758 | { | |
759 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); | |
760 | if (bdev->bd_holder == filp) | |
761 | bd_release(bdev); | |
762 | return blkdev_put(bdev); | |
763 | } | |
764 | ||
765 | static ssize_t blkdev_file_write(struct file *file, const char __user *buf, | |
766 | size_t count, loff_t *ppos) | |
767 | { | |
768 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
769 | ||
770 | return generic_file_write_nolock(file, &local_iov, 1, ppos); | |
771 | } | |
772 | ||
773 | static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf, | |
774 | size_t count, loff_t pos) | |
775 | { | |
776 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
777 | ||
778 | return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos); | |
779 | } | |
780 | ||
bb93e3a5 | 781 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
1da177e4 LT |
782 | { |
783 | return blkdev_ioctl(file->f_mapping->host, file, cmd, arg); | |
784 | } | |
785 | ||
786 | struct address_space_operations def_blk_aops = { | |
787 | .readpage = blkdev_readpage, | |
788 | .writepage = blkdev_writepage, | |
789 | .sync_page = block_sync_page, | |
790 | .prepare_write = blkdev_prepare_write, | |
791 | .commit_write = blkdev_commit_write, | |
792 | .writepages = generic_writepages, | |
793 | .direct_IO = blkdev_direct_IO, | |
794 | }; | |
795 | ||
796 | struct file_operations def_blk_fops = { | |
797 | .open = blkdev_open, | |
798 | .release = blkdev_close, | |
799 | .llseek = block_llseek, | |
800 | .read = generic_file_read, | |
801 | .write = blkdev_file_write, | |
802 | .aio_read = generic_file_aio_read, | |
803 | .aio_write = blkdev_file_aio_write, | |
804 | .mmap = generic_file_mmap, | |
805 | .fsync = block_fsync, | |
bb93e3a5 | 806 | .unlocked_ioctl = block_ioctl, |
1da177e4 LT |
807 | #ifdef CONFIG_COMPAT |
808 | .compat_ioctl = compat_blkdev_ioctl, | |
809 | #endif | |
810 | .readv = generic_file_readv, | |
811 | .writev = generic_file_write_nolock, | |
812 | .sendfile = generic_file_sendfile, | |
813 | }; | |
814 | ||
815 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
816 | { | |
817 | int res; | |
818 | mm_segment_t old_fs = get_fs(); | |
819 | set_fs(KERNEL_DS); | |
820 | res = blkdev_ioctl(bdev->bd_inode, NULL, cmd, arg); | |
821 | set_fs(old_fs); | |
822 | return res; | |
823 | } | |
824 | ||
825 | EXPORT_SYMBOL(ioctl_by_bdev); | |
826 | ||
827 | /** | |
828 | * lookup_bdev - lookup a struct block_device by name | |
829 | * | |
830 | * @path: special file representing the block device | |
831 | * | |
832 | * Get a reference to the blockdevice at @path in the current | |
833 | * namespace if possible and return it. Return ERR_PTR(error) | |
834 | * otherwise. | |
835 | */ | |
836 | struct block_device *lookup_bdev(const char *path) | |
837 | { | |
838 | struct block_device *bdev; | |
839 | struct inode *inode; | |
840 | struct nameidata nd; | |
841 | int error; | |
842 | ||
843 | if (!path || !*path) | |
844 | return ERR_PTR(-EINVAL); | |
845 | ||
846 | error = path_lookup(path, LOOKUP_FOLLOW, &nd); | |
847 | if (error) | |
848 | return ERR_PTR(error); | |
849 | ||
850 | inode = nd.dentry->d_inode; | |
851 | error = -ENOTBLK; | |
852 | if (!S_ISBLK(inode->i_mode)) | |
853 | goto fail; | |
854 | error = -EACCES; | |
855 | if (nd.mnt->mnt_flags & MNT_NODEV) | |
856 | goto fail; | |
857 | error = -ENOMEM; | |
858 | bdev = bd_acquire(inode); | |
859 | if (!bdev) | |
860 | goto fail; | |
861 | out: | |
862 | path_release(&nd); | |
863 | return bdev; | |
864 | fail: | |
865 | bdev = ERR_PTR(error); | |
866 | goto out; | |
867 | } | |
868 | ||
869 | /** | |
870 | * open_bdev_excl - open a block device by name and set it up for use | |
871 | * | |
872 | * @path: special file representing the block device | |
873 | * @flags: %MS_RDONLY for opening read-only | |
874 | * @holder: owner for exclusion | |
875 | * | |
876 | * Open the blockdevice described by the special file at @path, claim it | |
877 | * for the @holder. | |
878 | */ | |
879 | struct block_device *open_bdev_excl(const char *path, int flags, void *holder) | |
880 | { | |
881 | struct block_device *bdev; | |
882 | mode_t mode = FMODE_READ; | |
883 | int error = 0; | |
884 | ||
885 | bdev = lookup_bdev(path); | |
886 | if (IS_ERR(bdev)) | |
887 | return bdev; | |
888 | ||
889 | if (!(flags & MS_RDONLY)) | |
890 | mode |= FMODE_WRITE; | |
891 | error = blkdev_get(bdev, mode, 0); | |
892 | if (error) | |
893 | return ERR_PTR(error); | |
894 | error = -EACCES; | |
895 | if (!(flags & MS_RDONLY) && bdev_read_only(bdev)) | |
896 | goto blkdev_put; | |
897 | error = bd_claim(bdev, holder); | |
898 | if (error) | |
899 | goto blkdev_put; | |
900 | ||
901 | return bdev; | |
902 | ||
903 | blkdev_put: | |
904 | blkdev_put(bdev); | |
905 | return ERR_PTR(error); | |
906 | } | |
907 | ||
908 | EXPORT_SYMBOL(open_bdev_excl); | |
909 | ||
910 | /** | |
911 | * close_bdev_excl - release a blockdevice openen by open_bdev_excl() | |
912 | * | |
913 | * @bdev: blockdevice to close | |
914 | * | |
915 | * This is the counterpart to open_bdev_excl(). | |
916 | */ | |
917 | void close_bdev_excl(struct block_device *bdev) | |
918 | { | |
919 | bd_release(bdev); | |
920 | blkdev_put(bdev); | |
921 | } | |
922 | ||
923 | EXPORT_SYMBOL(close_bdev_excl); |