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[TG3]: Set minimal hw interrupt mitigation.
[linux-2.6/verdex.git] / fs / block_dev.c
blobc0cbd1bc1a02106dbaea65cb22d20bf22543f84a
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);
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