blob: 2d096057ab53084bac4180f089830d9195cba919 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
28struct bdev_inode {
29 struct block_device bdev;
30 struct inode vfs_inode;
31};
32
33static inline struct bdev_inode *BDEV_I(struct inode *inode)
34{
35 return container_of(inode, struct bdev_inode, vfs_inode);
36}
37
38inline struct block_device *I_BDEV(struct inode *inode)
39{
40 return &BDEV_I(inode)->bdev;
41}
42
43EXPORT_SYMBOL(I_BDEV);
44
45static 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.. */
59static 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
65int 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
85EXPORT_SYMBOL(set_blocksize);
86
87int 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
102EXPORT_SYMBOL(sb_set_blocksize);
103
104int 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
112EXPORT_SYMBOL(sb_min_blocksize);
113
114static int
115blkdev_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
136static int
137blkdev_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
163static ssize_t
164blkdev_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
174static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
175{
176 return block_write_full_page(page, blkdev_get_block, wbc);
177}
178
179static int blkdev_readpage(struct file * file, struct page * page)
180{
181 return block_read_full_page(page, blkdev_get_block);
182}
183
184static 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
189static 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 */
199static 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
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800205 mutex_lock(&bd_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 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 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800222 mutex_unlock(&bd_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 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
231static 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
240static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
241static kmem_cache_t * bdev_cachep;
242
243static 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
251static 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
259static 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));
Arjan van de Venc039e312006-03-23 03:00:28 -0800268 mutex_init(&bdev->bd_mutex);
269 mutex_init(&bdev->bd_mount_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 INIT_LIST_HEAD(&bdev->bd_inodes);
271 INIT_LIST_HEAD(&bdev->bd_list);
272 inode_init_once(&ei->vfs_inode);
273 }
274}
275
276static 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
283static 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
295static 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
303static 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
309static struct file_system_type bd_type = {
310 .name = "bdev",
311 .get_sb = bd_get_sb,
312 .kill_sb = kill_anon_super,
313};
314
315static struct vfsmount *bd_mnt;
316struct super_block *blockdev_superblock;
317
318void __init bdev_cache_init(void)
319{
320 int err;
321 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
Paul Jacksonfffb60f2006-03-24 03:16:06 -0800322 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
323 SLAB_MEM_SPREAD|SLAB_PANIC),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 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 */
340static inline unsigned long hash(dev_t dev)
341{
342 return MAJOR(dev)+MINOR(dev);
343}
344
345static int bdev_test(struct inode *inode, void *data)
346{
347 return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
348}
349
350static int bdev_set(struct inode *inode, void *data)
351{
352 BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
353 return 0;
354}
355
356static LIST_HEAD(all_bdevs);
357
358struct 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
391EXPORT_SYMBOL(bdget);
392
393long 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
407void bdput(struct block_device *bdev)
408{
409 iput(bdev->bd_inode);
410}
411
412EXPORT_SYMBOL(bdput);
413
414static 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
439void 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
447int 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
482EXPORT_SYMBOL(bd_claim);
483
484void 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
494EXPORT_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 */
503struct 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
513EXPORT_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 */
524int 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
Christoph Hellwig2ef41632005-05-05 16:15:59 -0700534 if (__invalidate_device(bdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 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
544EXPORT_SYMBOL(check_disk_change);
545
546void 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}
559EXPORT_SYMBOL(bd_set_size);
560
561static 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
Arjan van de Venc039e312006-03-23 03:00:28 -0800578 mutex_lock(&bdev->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 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;
Arjan van de Venc039e312006-03-23 03:00:28 -0800609 mutex_lock(&whole->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 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--;
Arjan van de Venc039e312006-03-23 03:00:28 -0800616 mutex_unlock(&whole->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 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);
Arjan van de Venc039e312006-03-23 03:00:28 -0800623 mutex_unlock(&whole->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 }
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 {
Arjan van de Venc039e312006-03-23 03:00:28 -0800637 mutex_lock(&bdev->bd_contains->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 bdev->bd_contains->bd_part_count++;
Arjan van de Venc039e312006-03-23 03:00:28 -0800639 mutex_unlock(&bdev->bd_contains->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 }
641 }
642 bdev->bd_openers++;
Arjan van de Venc039e312006-03-23 03:00:28 -0800643 mutex_unlock(&bdev->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 unlock_kernel();
645 return 0;
646
647out_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);
655out:
Arjan van de Venc039e312006-03-23 03:00:28 -0800656 mutex_unlock(&bdev->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 unlock_kernel();
658 if (ret)
659 bdput(bdev);
660 return ret;
661}
662
663int 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
681EXPORT_SYMBOL(blkdev_get);
682
683static 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
712int 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
Arjan van de Venc039e312006-03-23 03:00:28 -0800718 mutex_lock(&bdev->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 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 {
Arjan van de Venc039e312006-03-23 03:00:28 -0800728 mutex_lock(&bdev->bd_contains->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 bdev->bd_contains->bd_part_count--;
Arjan van de Venc039e312006-03-23 03:00:28 -0800730 mutex_unlock(&bdev->bd_contains->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 }
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();
Arjan van de Venc039e312006-03-23 03:00:28 -0800750 mutex_unlock(&bdev->bd_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 bdput(bdev);
752 return ret;
753}
754
755EXPORT_SYMBOL(blkdev_put);
756
757static 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
765static 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
773static 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
Arnd Bergmannbb93e3a2005-06-23 00:10:15 -0700781static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782{
783 return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
784}
785
786struct 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
796struct 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,
Arnd Bergmannbb93e3a2005-06-23 00:10:15 -0700806 .unlocked_ioctl = block_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807#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
815int 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
825EXPORT_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 */
836struct 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;
861out:
862 path_release(&nd);
863 return bdev;
864fail:
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 */
879struct 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
903blkdev_put:
904 blkdev_put(bdev);
905 return ERR_PTR(error);
906}
907
908EXPORT_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 */
917void close_bdev_excl(struct block_device *bdev)
918{
919 bd_release(bdev);
920 blkdev_put(bdev);
921}
922
923EXPORT_SYMBOL(close_bdev_excl);