Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/fs/block_dev.c
Parent Directory | Revision Log
Revision 630 -
(show annotations)
(download)
Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 22208 byte(s)
Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 22208 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | |
205 | down(&bd_inode->i_sem); |
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 | } |
222 | up(&bd_inode->i_sem); |
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)); |
268 | sema_init(&bdev->bd_sem, 1); |
269 | sema_init(&bdev->bd_mount_sem, 1); |
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), |
322 | 0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_PANIC, |
323 | init_once, NULL); |
324 | err = register_filesystem(&bd_type); |
325 | if (err) |
326 | panic("Cannot register bdev pseudo-fs"); |
327 | bd_mnt = kern_mount(&bd_type); |
328 | err = PTR_ERR(bd_mnt); |
329 | if (IS_ERR(bd_mnt)) |
330 | panic("Cannot create bdev pseudo-fs"); |
331 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
332 | } |
333 | |
334 | /* |
335 | * Most likely _very_ bad one - but then it's hardly critical for small |
336 | * /dev and can be fixed when somebody will need really large one. |
337 | * Keep in mind that it will be fed through icache hash function too. |
338 | */ |
339 | static inline unsigned long hash(dev_t dev) |
340 | { |
341 | return MAJOR(dev)+MINOR(dev); |
342 | } |
343 | |
344 | static int bdev_test(struct inode *inode, void *data) |
345 | { |
346 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; |
347 | } |
348 | |
349 | static int bdev_set(struct inode *inode, void *data) |
350 | { |
351 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; |
352 | return 0; |
353 | } |
354 | |
355 | static LIST_HEAD(all_bdevs); |
356 | |
357 | struct block_device *bdget(dev_t dev) |
358 | { |
359 | struct block_device *bdev; |
360 | struct inode *inode; |
361 | |
362 | inode = iget5_locked(bd_mnt->mnt_sb, hash(dev), |
363 | bdev_test, bdev_set, &dev); |
364 | |
365 | if (!inode) |
366 | return NULL; |
367 | |
368 | bdev = &BDEV_I(inode)->bdev; |
369 | |
370 | if (inode->i_state & I_NEW) { |
371 | bdev->bd_contains = NULL; |
372 | bdev->bd_inode = inode; |
373 | bdev->bd_block_size = (1 << inode->i_blkbits); |
374 | bdev->bd_part_count = 0; |
375 | bdev->bd_invalidated = 0; |
376 | inode->i_mode = S_IFBLK; |
377 | inode->i_rdev = dev; |
378 | inode->i_bdev = bdev; |
379 | inode->i_data.a_ops = &def_blk_aops; |
380 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); |
381 | inode->i_data.backing_dev_info = &default_backing_dev_info; |
382 | spin_lock(&bdev_lock); |
383 | list_add(&bdev->bd_list, &all_bdevs); |
384 | spin_unlock(&bdev_lock); |
385 | unlock_new_inode(inode); |
386 | } |
387 | return bdev; |
388 | } |
389 | |
390 | EXPORT_SYMBOL(bdget); |
391 | |
392 | long nr_blockdev_pages(void) |
393 | { |
394 | struct list_head *p; |
395 | long ret = 0; |
396 | spin_lock(&bdev_lock); |
397 | list_for_each(p, &all_bdevs) { |
398 | struct block_device *bdev; |
399 | bdev = list_entry(p, struct block_device, bd_list); |
400 | ret += bdev->bd_inode->i_mapping->nrpages; |
401 | } |
402 | spin_unlock(&bdev_lock); |
403 | return ret; |
404 | } |
405 | |
406 | void bdput(struct block_device *bdev) |
407 | { |
408 | iput(bdev->bd_inode); |
409 | } |
410 | |
411 | EXPORT_SYMBOL(bdput); |
412 | |
413 | static struct block_device *bd_acquire(struct inode *inode) |
414 | { |
415 | struct block_device *bdev; |
416 | spin_lock(&bdev_lock); |
417 | bdev = inode->i_bdev; |
418 | if (bdev && igrab(bdev->bd_inode)) { |
419 | spin_unlock(&bdev_lock); |
420 | return bdev; |
421 | } |
422 | spin_unlock(&bdev_lock); |
423 | bdev = bdget(inode->i_rdev); |
424 | if (bdev) { |
425 | spin_lock(&bdev_lock); |
426 | if (inode->i_bdev) |
427 | __bd_forget(inode); |
428 | inode->i_bdev = bdev; |
429 | inode->i_mapping = bdev->bd_inode->i_mapping; |
430 | list_add(&inode->i_devices, &bdev->bd_inodes); |
431 | spin_unlock(&bdev_lock); |
432 | } |
433 | return bdev; |
434 | } |
435 | |
436 | /* Call when you free inode */ |
437 | |
438 | void bd_forget(struct inode *inode) |
439 | { |
440 | spin_lock(&bdev_lock); |
441 | if (inode->i_bdev) |
442 | __bd_forget(inode); |
443 | spin_unlock(&bdev_lock); |
444 | } |
445 | |
446 | int bd_claim(struct block_device *bdev, void *holder) |
447 | { |
448 | int res; |
449 | spin_lock(&bdev_lock); |
450 | |
451 | /* first decide result */ |
452 | if (bdev->bd_holder == holder) |
453 | res = 0; /* already a holder */ |
454 | else if (bdev->bd_holder != NULL) |
455 | res = -EBUSY; /* held by someone else */ |
456 | else if (bdev->bd_contains == bdev) |
457 | res = 0; /* is a whole device which isn't held */ |
458 | |
459 | else if (bdev->bd_contains->bd_holder == bd_claim) |
460 | res = 0; /* is a partition of a device that is being partitioned */ |
461 | else if (bdev->bd_contains->bd_holder != NULL) |
462 | res = -EBUSY; /* is a partition of a held device */ |
463 | else |
464 | res = 0; /* is a partition of an un-held device */ |
465 | |
466 | /* now impose change */ |
467 | if (res==0) { |
468 | /* note that for a whole device bd_holders |
469 | * will be incremented twice, and bd_holder will |
470 | * be set to bd_claim before being set to holder |
471 | */ |
472 | bdev->bd_contains->bd_holders ++; |
473 | bdev->bd_contains->bd_holder = bd_claim; |
474 | bdev->bd_holders++; |
475 | bdev->bd_holder = holder; |
476 | } |
477 | spin_unlock(&bdev_lock); |
478 | return res; |
479 | } |
480 | |
481 | EXPORT_SYMBOL(bd_claim); |
482 | |
483 | void bd_release(struct block_device *bdev) |
484 | { |
485 | spin_lock(&bdev_lock); |
486 | if (!--bdev->bd_contains->bd_holders) |
487 | bdev->bd_contains->bd_holder = NULL; |
488 | if (!--bdev->bd_holders) |
489 | bdev->bd_holder = NULL; |
490 | spin_unlock(&bdev_lock); |
491 | } |
492 | |
493 | EXPORT_SYMBOL(bd_release); |
494 | |
495 | /* |
496 | * Tries to open block device by device number. Use it ONLY if you |
497 | * really do not have anything better - i.e. when you are behind a |
498 | * truly sucky interface and all you are given is a device number. _Never_ |
499 | * to be used for internal purposes. If you ever need it - reconsider |
500 | * your API. |
501 | */ |
502 | struct block_device *open_by_devnum(dev_t dev, unsigned mode) |
503 | { |
504 | struct block_device *bdev = bdget(dev); |
505 | int err = -ENOMEM; |
506 | int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY; |
507 | if (bdev) |
508 | err = blkdev_get(bdev, mode, flags); |
509 | return err ? ERR_PTR(err) : bdev; |
510 | } |
511 | |
512 | EXPORT_SYMBOL(open_by_devnum); |
513 | |
514 | /* |
515 | * This routine checks whether a removable media has been changed, |
516 | * and invalidates all buffer-cache-entries in that case. This |
517 | * is a relatively slow routine, so we have to try to minimize using |
518 | * it. Thus it is called only upon a 'mount' or 'open'. This |
519 | * is the best way of combining speed and utility, I think. |
520 | * People changing diskettes in the middle of an operation deserve |
521 | * to lose :-) |
522 | */ |
523 | int check_disk_change(struct block_device *bdev) |
524 | { |
525 | struct gendisk *disk = bdev->bd_disk; |
526 | struct block_device_operations * bdops = disk->fops; |
527 | |
528 | if (!bdops->media_changed) |
529 | return 0; |
530 | if (!bdops->media_changed(bdev->bd_disk)) |
531 | return 0; |
532 | |
533 | if (__invalidate_device(bdev)) |
534 | printk("VFS: busy inodes on changed media.\n"); |
535 | |
536 | if (bdops->revalidate_disk) |
537 | bdops->revalidate_disk(bdev->bd_disk); |
538 | if (bdev->bd_disk->minors > 1) |
539 | bdev->bd_invalidated = 1; |
540 | return 1; |
541 | } |
542 | |
543 | EXPORT_SYMBOL(check_disk_change); |
544 | |
545 | void bd_set_size(struct block_device *bdev, loff_t size) |
546 | { |
547 | unsigned bsize = bdev_hardsect_size(bdev); |
548 | |
549 | bdev->bd_inode->i_size = size; |
550 | while (bsize < PAGE_CACHE_SIZE) { |
551 | if (size & bsize) |
552 | break; |
553 | bsize <<= 1; |
554 | } |
555 | bdev->bd_block_size = bsize; |
556 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); |
557 | } |
558 | EXPORT_SYMBOL(bd_set_size); |
559 | |
560 | static int do_open(struct block_device *bdev, struct file *file) |
561 | { |
562 | struct module *owner = NULL; |
563 | struct gendisk *disk; |
564 | int ret = -ENXIO; |
565 | int part; |
566 | |
567 | file->f_mapping = bdev->bd_inode->i_mapping; |
568 | lock_kernel(); |
569 | disk = get_gendisk(bdev->bd_dev, &part); |
570 | if (!disk) { |
571 | unlock_kernel(); |
572 | bdput(bdev); |
573 | return ret; |
574 | } |
575 | owner = disk->fops->owner; |
576 | |
577 | down(&bdev->bd_sem); |
578 | if (!bdev->bd_openers) { |
579 | bdev->bd_disk = disk; |
580 | bdev->bd_contains = bdev; |
581 | if (!part) { |
582 | struct backing_dev_info *bdi; |
583 | if (disk->fops->open) { |
584 | ret = disk->fops->open(bdev->bd_inode, file); |
585 | if (ret) |
586 | goto out_first; |
587 | } |
588 | if (!bdev->bd_openers) { |
589 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
590 | bdi = blk_get_backing_dev_info(bdev); |
591 | if (bdi == NULL) |
592 | bdi = &default_backing_dev_info; |
593 | bdev->bd_inode->i_data.backing_dev_info = bdi; |
594 | } |
595 | if (bdev->bd_invalidated) |
596 | rescan_partitions(disk, bdev); |
597 | } else { |
598 | struct hd_struct *p; |
599 | struct block_device *whole; |
600 | whole = bdget_disk(disk, 0); |
601 | ret = -ENOMEM; |
602 | if (!whole) |
603 | goto out_first; |
604 | ret = blkdev_get(whole, file->f_mode, file->f_flags); |
605 | if (ret) |
606 | goto out_first; |
607 | bdev->bd_contains = whole; |
608 | down(&whole->bd_sem); |
609 | whole->bd_part_count++; |
610 | p = disk->part[part - 1]; |
611 | bdev->bd_inode->i_data.backing_dev_info = |
612 | whole->bd_inode->i_data.backing_dev_info; |
613 | if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) { |
614 | whole->bd_part_count--; |
615 | up(&whole->bd_sem); |
616 | ret = -ENXIO; |
617 | goto out_first; |
618 | } |
619 | kobject_get(&p->kobj); |
620 | bdev->bd_part = p; |
621 | bd_set_size(bdev, (loff_t) p->nr_sects << 9); |
622 | up(&whole->bd_sem); |
623 | } |
624 | } else { |
625 | put_disk(disk); |
626 | module_put(owner); |
627 | if (bdev->bd_contains == bdev) { |
628 | if (bdev->bd_disk->fops->open) { |
629 | ret = bdev->bd_disk->fops->open(bdev->bd_inode, file); |
630 | if (ret) |
631 | goto out; |
632 | } |
633 | if (bdev->bd_invalidated) |
634 | rescan_partitions(bdev->bd_disk, bdev); |
635 | } else { |
636 | down(&bdev->bd_contains->bd_sem); |
637 | bdev->bd_contains->bd_part_count++; |
638 | up(&bdev->bd_contains->bd_sem); |
639 | } |
640 | } |
641 | bdev->bd_openers++; |
642 | up(&bdev->bd_sem); |
643 | unlock_kernel(); |
644 | return 0; |
645 | |
646 | out_first: |
647 | bdev->bd_disk = NULL; |
648 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; |
649 | if (bdev != bdev->bd_contains) |
650 | blkdev_put(bdev->bd_contains); |
651 | bdev->bd_contains = NULL; |
652 | put_disk(disk); |
653 | module_put(owner); |
654 | out: |
655 | up(&bdev->bd_sem); |
656 | unlock_kernel(); |
657 | if (ret) |
658 | bdput(bdev); |
659 | return ret; |
660 | } |
661 | |
662 | int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags) |
663 | { |
664 | /* |
665 | * This crockload is due to bad choice of ->open() type. |
666 | * It will go away. |
667 | * For now, block device ->open() routine must _not_ |
668 | * examine anything in 'inode' argument except ->i_rdev. |
669 | */ |
670 | struct file fake_file = {}; |
671 | struct dentry fake_dentry = {}; |
672 | fake_file.f_mode = mode; |
673 | fake_file.f_flags = flags; |
674 | fake_file.f_dentry = &fake_dentry; |
675 | fake_dentry.d_inode = bdev->bd_inode; |
676 | |
677 | return do_open(bdev, &fake_file); |
678 | } |
679 | |
680 | EXPORT_SYMBOL(blkdev_get); |
681 | |
682 | static int blkdev_open(struct inode * inode, struct file * filp) |
683 | { |
684 | struct block_device *bdev; |
685 | int res; |
686 | |
687 | /* |
688 | * Preserve backwards compatibility and allow large file access |
689 | * even if userspace doesn't ask for it explicitly. Some mkfs |
690 | * binary needs it. We might want to drop this workaround |
691 | * during an unstable branch. |
692 | */ |
693 | filp->f_flags |= O_LARGEFILE; |
694 | |
695 | bdev = bd_acquire(inode); |
696 | |
697 | res = do_open(bdev, filp); |
698 | if (res) |
699 | return res; |
700 | |
701 | if (!(filp->f_flags & O_EXCL) ) |
702 | return 0; |
703 | |
704 | if (!(res = bd_claim(bdev, filp))) |
705 | return 0; |
706 | |
707 | blkdev_put(bdev); |
708 | return res; |
709 | } |
710 | |
711 | int blkdev_put(struct block_device *bdev) |
712 | { |
713 | int ret = 0; |
714 | struct inode *bd_inode = bdev->bd_inode; |
715 | struct gendisk *disk = bdev->bd_disk; |
716 | |
717 | down(&bdev->bd_sem); |
718 | lock_kernel(); |
719 | if (!--bdev->bd_openers) { |
720 | sync_blockdev(bdev); |
721 | kill_bdev(bdev); |
722 | } |
723 | if (bdev->bd_contains == bdev) { |
724 | if (disk->fops->release) |
725 | ret = disk->fops->release(bd_inode, NULL); |
726 | } else { |
727 | down(&bdev->bd_contains->bd_sem); |
728 | bdev->bd_contains->bd_part_count--; |
729 | up(&bdev->bd_contains->bd_sem); |
730 | } |
731 | if (!bdev->bd_openers) { |
732 | struct module *owner = disk->fops->owner; |
733 | |
734 | put_disk(disk); |
735 | module_put(owner); |
736 | |
737 | if (bdev->bd_contains != bdev) { |
738 | kobject_put(&bdev->bd_part->kobj); |
739 | bdev->bd_part = NULL; |
740 | } |
741 | bdev->bd_disk = NULL; |
742 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; |
743 | if (bdev != bdev->bd_contains) { |
744 | blkdev_put(bdev->bd_contains); |
745 | } |
746 | bdev->bd_contains = NULL; |
747 | } |
748 | unlock_kernel(); |
749 | up(&bdev->bd_sem); |
750 | bdput(bdev); |
751 | return ret; |
752 | } |
753 | |
754 | EXPORT_SYMBOL(blkdev_put); |
755 | |
756 | static int blkdev_close(struct inode * inode, struct file * filp) |
757 | { |
758 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); |
759 | if (bdev->bd_holder == filp) |
760 | bd_release(bdev); |
761 | return blkdev_put(bdev); |
762 | } |
763 | |
764 | static ssize_t blkdev_file_write(struct file *file, const char __user *buf, |
765 | size_t count, loff_t *ppos) |
766 | { |
767 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; |
768 | |
769 | return generic_file_write_nolock(file, &local_iov, 1, ppos); |
770 | } |
771 | |
772 | static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf, |
773 | size_t count, loff_t pos) |
774 | { |
775 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; |
776 | |
777 | return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos); |
778 | } |
779 | |
780 | static int block_ioctl(struct inode *inode, struct file *file, unsigned cmd, |
781 | unsigned long arg) |
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, |
806 | .ioctl = block_ioctl, |
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); |