4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
8 #include <linux/init.h>
10 #include <linux/fcntl.h>
11 #include <linux/slab.h>
12 #include <linux/kmod.h>
13 #include <linux/major.h>
14 #include <linux/smp_lock.h>
15 #include <linux/highmem.h>
16 #include <linux/blkdev.h>
17 #include <linux/module.h>
18 #include <linux/blkpg.h>
19 #include <linux/buffer_head.h>
20 #include <linux/mpage.h>
21 #include <linux/mount.h>
22 #include <linux/uio.h>
23 #include <linux/namei.h>
24 #include <asm/uaccess.h>
27 struct block_device bdev;
28 struct inode vfs_inode;
31 static inline struct bdev_inode *BDEV_I(struct inode *inode)
33 return container_of(inode, struct bdev_inode, vfs_inode);
36 inline struct block_device *I_BDEV(struct inode *inode)
38 return &BDEV_I(inode)->bdev;
41 EXPORT_SYMBOL(I_BDEV);
43 static sector_t max_block(struct block_device *bdev)
45 sector_t retval = ~((sector_t)0);
46 loff_t sz = i_size_read(bdev->bd_inode);
49 unsigned int size = block_size(bdev);
50 unsigned int sizebits = blksize_bits(size);
51 retval = (sz >> sizebits);
56 /* Kill _all_ buffers, dirty or not.. */
57 static void kill_bdev(struct block_device *bdev)
59 invalidate_bdev(bdev, 1);
60 truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
63 int set_blocksize(struct block_device *bdev, int size)
65 /* Size must be a power of two, and between 512 and PAGE_SIZE */
66 if (size > PAGE_SIZE || size < 512 || (size & (size-1)))
69 /* Size cannot be smaller than the size supported by the device */
70 if (size < bdev_hardsect_size(bdev))
73 /* Don't change the size if it is same as current */
74 if (bdev->bd_block_size != size) {
76 bdev->bd_block_size = size;
77 bdev->bd_inode->i_blkbits = blksize_bits(size);
83 EXPORT_SYMBOL(set_blocksize);
85 int sb_set_blocksize(struct super_block *sb, int size)
87 if (set_blocksize(sb->s_bdev, size))
89 /* If we get here, we know size is power of two
90 * and it's value is between 512 and PAGE_SIZE */
91 sb->s_blocksize = size;
92 sb->s_blocksize_bits = blksize_bits(size);
93 return sb->s_blocksize;
96 EXPORT_SYMBOL(sb_set_blocksize);
98 int sb_min_blocksize(struct super_block *sb, int size)
100 int minsize = bdev_hardsect_size(sb->s_bdev);
103 return sb_set_blocksize(sb, size);
106 EXPORT_SYMBOL(sb_min_blocksize);
109 blkdev_get_block(struct inode *inode, sector_t iblock,
110 struct buffer_head *bh, int create)
112 if (iblock >= max_block(I_BDEV(inode))) {
117 * for reads, we're just trying to fill a partial page.
118 * return a hole, they will have to call get_block again
119 * before they can fill it, and they will get -EIO at that
124 bh->b_bdev = I_BDEV(inode);
125 bh->b_blocknr = iblock;
126 set_buffer_mapped(bh);
131 blkdev_get_blocks(struct inode *inode, sector_t iblock,
132 struct buffer_head *bh, int create)
134 sector_t end_block = max_block(I_BDEV(inode));
135 unsigned long max_blocks = bh->b_size >> inode->i_blkbits;
137 if ((iblock + max_blocks) > end_block) {
138 max_blocks = end_block - iblock;
139 if ((long)max_blocks <= 0) {
141 return -EIO; /* write fully beyond EOF */
143 * It is a read which is fully beyond EOF. We return
144 * a !buffer_mapped buffer
150 bh->b_bdev = I_BDEV(inode);
151 bh->b_blocknr = iblock;
152 bh->b_size = max_blocks << inode->i_blkbits;
154 set_buffer_mapped(bh);
159 blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
160 loff_t offset, unsigned long nr_segs)
162 struct file *file = iocb->ki_filp;
163 struct inode *inode = file->f_mapping->host;
165 return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode),
166 iov, offset, nr_segs, blkdev_get_blocks, NULL);
169 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
171 return block_write_full_page(page, blkdev_get_block, wbc);
174 static int blkdev_readpage(struct file * file, struct page * page)
176 return block_read_full_page(page, blkdev_get_block);
179 static int blkdev_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
181 return block_prepare_write(page, from, to, blkdev_get_block);
184 static int blkdev_commit_write(struct file *file, struct page *page, unsigned from, unsigned to)
186 return block_commit_write(page, from, to);
191 * for a block special file file->f_dentry->d_inode->i_size is zero
192 * so we compute the size by hand (just as in block_read/write above)
194 static loff_t block_llseek(struct file *file, loff_t offset, int origin)
196 struct inode *bd_inode = file->f_mapping->host;
200 mutex_lock(&bd_inode->i_mutex);
201 size = i_size_read(bd_inode);
208 offset += file->f_pos;
211 if (offset >= 0 && offset <= size) {
212 if (offset != file->f_pos) {
213 file->f_pos = offset;
217 mutex_unlock(&bd_inode->i_mutex);
222 * Filp is never NULL; the only case when ->fsync() is called with
223 * NULL first argument is nfsd_sync_dir() and that's not a directory.
226 static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
228 return sync_blockdev(I_BDEV(filp->f_mapping->host));
235 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
236 static kmem_cache_t * bdev_cachep __read_mostly;
238 static struct inode *bdev_alloc_inode(struct super_block *sb)
240 struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL);
243 return &ei->vfs_inode;
246 static void bdev_destroy_inode(struct inode *inode)
248 struct bdev_inode *bdi = BDEV_I(inode);
250 bdi->bdev.bd_inode_backing_dev_info = NULL;
251 kmem_cache_free(bdev_cachep, bdi);
254 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
256 struct bdev_inode *ei = (struct bdev_inode *) foo;
257 struct block_device *bdev = &ei->bdev;
259 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
260 SLAB_CTOR_CONSTRUCTOR)
262 memset(bdev, 0, sizeof(*bdev));
263 mutex_init(&bdev->bd_mount_mutex);
264 INIT_LIST_HEAD(&bdev->bd_inodes);
265 INIT_LIST_HEAD(&bdev->bd_list);
267 INIT_LIST_HEAD(&bdev->bd_holder_list);
269 inode_init_once(&ei->vfs_inode);
273 static inline void __bd_forget(struct inode *inode)
275 list_del_init(&inode->i_devices);
276 inode->i_bdev = NULL;
277 inode->i_mapping = &inode->i_data;
280 static void bdev_clear_inode(struct inode *inode)
282 struct block_device *bdev = &BDEV_I(inode)->bdev;
284 spin_lock(&bdev_lock);
285 while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
286 __bd_forget(list_entry(p, struct inode, i_devices));
288 list_del_init(&bdev->bd_list);
289 spin_unlock(&bdev_lock);
292 static struct super_operations bdev_sops = {
293 .statfs = simple_statfs,
294 .alloc_inode = bdev_alloc_inode,
295 .destroy_inode = bdev_destroy_inode,
296 .drop_inode = generic_delete_inode,
297 .clear_inode = bdev_clear_inode,
300 static int bd_get_sb(struct file_system_type *fs_type,
301 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
303 return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
306 static struct file_system_type bd_type = {
309 .kill_sb = kill_anon_super,
312 static struct vfsmount *bd_mnt __read_mostly;
313 struct super_block *blockdev_superblock;
315 void __init bdev_cache_init(void)
318 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
319 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
320 SLAB_MEM_SPREAD|SLAB_PANIC),
322 err = register_filesystem(&bd_type);
324 panic("Cannot register bdev pseudo-fs");
325 bd_mnt = kern_mount(&bd_type);
326 err = PTR_ERR(bd_mnt);
328 panic("Cannot create bdev pseudo-fs");
329 blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
333 * Most likely _very_ bad one - but then it's hardly critical for small
334 * /dev and can be fixed when somebody will need really large one.
335 * Keep in mind that it will be fed through icache hash function too.
337 static inline unsigned long hash(dev_t dev)
339 return MAJOR(dev)+MINOR(dev);
342 static int bdev_test(struct inode *inode, void *data)
344 return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
347 static int bdev_set(struct inode *inode, void *data)
349 BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
353 static LIST_HEAD(all_bdevs);
355 static struct lock_class_key bdev_part_lock_key;
357 struct block_device *bdget(dev_t dev)
359 struct block_device *bdev;
361 struct gendisk *disk;
364 inode = iget5_locked(bd_mnt->mnt_sb, hash(dev),
365 bdev_test, bdev_set, &dev);
370 bdev = &BDEV_I(inode)->bdev;
372 if (inode->i_state & I_NEW) {
373 bdev->bd_contains = NULL;
374 bdev->bd_inode = inode;
375 bdev->bd_block_size = (1 << inode->i_blkbits);
376 bdev->bd_part_count = 0;
377 bdev->bd_invalidated = 0;
378 inode->i_mode = S_IFBLK;
380 inode->i_bdev = bdev;
381 inode->i_data.a_ops = &def_blk_aops;
382 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
383 inode->i_data.backing_dev_info = &default_backing_dev_info;
384 spin_lock(&bdev_lock);
385 list_add(&bdev->bd_list, &all_bdevs);
386 spin_unlock(&bdev_lock);
387 unlock_new_inode(inode);
388 mutex_init(&bdev->bd_mutex);
389 disk = get_gendisk(dev, &part);
391 lockdep_set_class(&bdev->bd_mutex, &bdev_part_lock_key);
397 EXPORT_SYMBOL(bdget);
399 long nr_blockdev_pages(void)
403 spin_lock(&bdev_lock);
404 list_for_each(p, &all_bdevs) {
405 struct block_device *bdev;
406 bdev = list_entry(p, struct block_device, bd_list);
407 ret += bdev->bd_inode->i_mapping->nrpages;
409 spin_unlock(&bdev_lock);
413 void bdput(struct block_device *bdev)
415 iput(bdev->bd_inode);
418 EXPORT_SYMBOL(bdput);
420 static struct block_device *bd_acquire(struct inode *inode)
422 struct block_device *bdev;
424 spin_lock(&bdev_lock);
425 bdev = inode->i_bdev;
427 atomic_inc(&bdev->bd_inode->i_count);
428 spin_unlock(&bdev_lock);
431 spin_unlock(&bdev_lock);
433 bdev = bdget(inode->i_rdev);
435 spin_lock(&bdev_lock);
436 if (!inode->i_bdev) {
438 * We take an additional bd_inode->i_count for inode,
439 * and it's released in clear_inode() of inode.
440 * So, we can access it via ->i_mapping always
443 atomic_inc(&bdev->bd_inode->i_count);
444 inode->i_bdev = bdev;
445 inode->i_mapping = bdev->bd_inode->i_mapping;
446 list_add(&inode->i_devices, &bdev->bd_inodes);
448 spin_unlock(&bdev_lock);
453 /* Call when you free inode */
455 void bd_forget(struct inode *inode)
457 struct block_device *bdev = NULL;
459 spin_lock(&bdev_lock);
461 if (inode->i_sb != blockdev_superblock)
462 bdev = inode->i_bdev;
465 spin_unlock(&bdev_lock);
468 iput(bdev->bd_inode);
471 int bd_claim(struct block_device *bdev, void *holder)
474 spin_lock(&bdev_lock);
476 /* first decide result */
477 if (bdev->bd_holder == holder)
478 res = 0; /* already a holder */
479 else if (bdev->bd_holder != NULL)
480 res = -EBUSY; /* held by someone else */
481 else if (bdev->bd_contains == bdev)
482 res = 0; /* is a whole device which isn't held */
484 else if (bdev->bd_contains->bd_holder == bd_claim)
485 res = 0; /* is a partition of a device that is being partitioned */
486 else if (bdev->bd_contains->bd_holder != NULL)
487 res = -EBUSY; /* is a partition of a held device */
489 res = 0; /* is a partition of an un-held device */
491 /* now impose change */
493 /* note that for a whole device bd_holders
494 * will be incremented twice, and bd_holder will
495 * be set to bd_claim before being set to holder
497 bdev->bd_contains->bd_holders ++;
498 bdev->bd_contains->bd_holder = bd_claim;
500 bdev->bd_holder = holder;
502 spin_unlock(&bdev_lock);
506 EXPORT_SYMBOL(bd_claim);
508 void bd_release(struct block_device *bdev)
510 spin_lock(&bdev_lock);
511 if (!--bdev->bd_contains->bd_holders)
512 bdev->bd_contains->bd_holder = NULL;
513 if (!--bdev->bd_holders)
514 bdev->bd_holder = NULL;
515 spin_unlock(&bdev_lock);
518 EXPORT_SYMBOL(bd_release);
522 * Functions for bd_claim_by_kobject / bd_release_from_kobject
524 * If a kobject is passed to bd_claim_by_kobject()
525 * and the kobject has a parent directory,
526 * following symlinks are created:
527 * o from the kobject to the claimed bdev
528 * o from "holders" directory of the bdev to the parent of the kobject
529 * bd_release_from_kobject() removes these symlinks.
532 * If /dev/dm-0 maps to /dev/sda, kobject corresponding to
533 * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
534 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
535 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
538 static struct kobject *bdev_get_kobj(struct block_device *bdev)
540 if (bdev->bd_contains != bdev)
541 return kobject_get(&bdev->bd_part->kobj);
543 return kobject_get(&bdev->bd_disk->kobj);
546 static struct kobject *bdev_get_holder(struct block_device *bdev)
548 if (bdev->bd_contains != bdev)
549 return kobject_get(bdev->bd_part->holder_dir);
551 return kobject_get(bdev->bd_disk->holder_dir);
554 static void add_symlink(struct kobject *from, struct kobject *to)
558 sysfs_create_link(from, to, kobject_name(to));
561 static void del_symlink(struct kobject *from, struct kobject *to)
565 sysfs_remove_link(from, kobject_name(to));
569 * 'struct bd_holder' contains pointers to kobjects symlinked by
570 * bd_claim_by_kobject.
571 * It's connected to bd_holder_list which is protected by bdev->bd_sem.
574 struct list_head list; /* chain of holders of the bdev */
575 int count; /* references from the holder */
576 struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */
577 struct kobject *hdev; /* e.g. "/block/dm-0" */
578 struct kobject *hdir; /* e.g. "/block/sda/holders" */
579 struct kobject *sdev; /* e.g. "/block/sda" */
583 * Get references of related kobjects at once.
584 * Returns 1 on success. 0 on failure.
586 * Should call bd_holder_release_dirs() after successful use.
588 static int bd_holder_grab_dirs(struct block_device *bdev,
589 struct bd_holder *bo)
594 bo->sdir = kobject_get(bo->sdir);
598 bo->hdev = kobject_get(bo->sdir->parent);
602 bo->sdev = bdev_get_kobj(bdev);
606 bo->hdir = bdev_get_holder(bdev);
613 kobject_put(bo->sdev);
615 kobject_put(bo->hdev);
617 kobject_put(bo->sdir);
622 /* Put references of related kobjects at once. */
623 static void bd_holder_release_dirs(struct bd_holder *bo)
625 kobject_put(bo->hdir);
626 kobject_put(bo->sdev);
627 kobject_put(bo->hdev);
628 kobject_put(bo->sdir);
631 static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
633 struct bd_holder *bo;
635 bo = kzalloc(sizeof(*bo), GFP_KERNEL);
645 static void free_bd_holder(struct bd_holder *bo)
651 * add_bd_holder - create sysfs symlinks for bd_claim() relationship
653 * @bdev: block device to be bd_claimed
654 * @bo: preallocated and initialized by alloc_bd_holder()
656 * If there is no matching entry with @bo in @bdev->bd_holder_list,
657 * add @bo to the list, create symlinks.
659 * Returns 1 if @bo was added to the list.
660 * Returns 0 if @bo wasn't used by any reason and should be freed.
662 static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
664 struct bd_holder *tmp;
669 list_for_each_entry(tmp, &bdev->bd_holder_list, list) {
670 if (tmp->sdir == bo->sdir) {
676 if (!bd_holder_grab_dirs(bdev, bo))
679 add_symlink(bo->sdir, bo->sdev);
680 add_symlink(bo->hdir, bo->hdev);
681 list_add_tail(&bo->list, &bdev->bd_holder_list);
686 * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
688 * @bdev: block device to be bd_claimed
689 * @kobj: holder's kobject
691 * If there is matching entry with @kobj in @bdev->bd_holder_list
692 * and no other bd_claim() from the same kobject,
693 * remove the struct bd_holder from the list, delete symlinks for it.
695 * Returns a pointer to the struct bd_holder when it's removed from the list
696 * and ready to be freed.
697 * Returns NULL if matching claim isn't found or there is other bd_claim()
698 * by the same kobject.
700 static struct bd_holder *del_bd_holder(struct block_device *bdev,
701 struct kobject *kobj)
703 struct bd_holder *bo;
705 list_for_each_entry(bo, &bdev->bd_holder_list, list) {
706 if (bo->sdir == kobj) {
708 BUG_ON(bo->count < 0);
711 del_symlink(bo->sdir, bo->sdev);
712 del_symlink(bo->hdir, bo->hdev);
713 bd_holder_release_dirs(bo);
724 * bd_claim_by_kobject - bd_claim() with additional kobject signature
726 * @bdev: block device to be claimed
727 * @holder: holder's signature
728 * @kobj: holder's kobject
730 * Do bd_claim() and if it succeeds, create sysfs symlinks between
731 * the bdev and the holder's kobject.
732 * Use bd_release_from_kobject() when relesing the claimed bdev.
734 * Returns 0 on success. (same as bd_claim())
735 * Returns errno on failure.
737 static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
738 struct kobject *kobj)
741 struct bd_holder *bo;
746 bo = alloc_bd_holder(kobj);
750 mutex_lock(&bdev->bd_mutex);
751 res = bd_claim(bdev, holder);
752 if (res || !add_bd_holder(bdev, bo))
754 mutex_unlock(&bdev->bd_mutex);
760 * bd_release_from_kobject - bd_release() with additional kobject signature
762 * @bdev: block device to be released
763 * @kobj: holder's kobject
765 * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
767 static void bd_release_from_kobject(struct block_device *bdev,
768 struct kobject *kobj)
770 struct bd_holder *bo;
775 mutex_lock(&bdev->bd_mutex);
777 if ((bo = del_bd_holder(bdev, kobj)))
779 mutex_unlock(&bdev->bd_mutex);
783 * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
785 * @bdev: block device to be claimed
786 * @holder: holder's signature
787 * @disk: holder's gendisk
789 * Call bd_claim_by_kobject() with getting @disk->slave_dir.
791 int bd_claim_by_disk(struct block_device *bdev, void *holder,
792 struct gendisk *disk)
794 return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
796 EXPORT_SYMBOL_GPL(bd_claim_by_disk);
799 * bd_release_from_disk - wrapper function for bd_release_from_kobject()
801 * @bdev: block device to be claimed
802 * @disk: holder's gendisk
804 * Call bd_release_from_kobject() and put @disk->slave_dir.
806 void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
808 bd_release_from_kobject(bdev, disk->slave_dir);
809 kobject_put(disk->slave_dir);
811 EXPORT_SYMBOL_GPL(bd_release_from_disk);
815 * Tries to open block device by device number. Use it ONLY if you
816 * really do not have anything better - i.e. when you are behind a
817 * truly sucky interface and all you are given is a device number. _Never_
818 * to be used for internal purposes. If you ever need it - reconsider
821 struct block_device *open_by_devnum(dev_t dev, unsigned mode)
823 struct block_device *bdev = bdget(dev);
825 int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY;
827 err = blkdev_get(bdev, mode, flags);
828 return err ? ERR_PTR(err) : bdev;
831 EXPORT_SYMBOL(open_by_devnum);
834 * This routine checks whether a removable media has been changed,
835 * and invalidates all buffer-cache-entries in that case. This
836 * is a relatively slow routine, so we have to try to minimize using
837 * it. Thus it is called only upon a 'mount' or 'open'. This
838 * is the best way of combining speed and utility, I think.
839 * People changing diskettes in the middle of an operation deserve
842 int check_disk_change(struct block_device *bdev)
844 struct gendisk *disk = bdev->bd_disk;
845 struct block_device_operations * bdops = disk->fops;
847 if (!bdops->media_changed)
849 if (!bdops->media_changed(bdev->bd_disk))
852 if (__invalidate_device(bdev))
853 printk("VFS: busy inodes on changed media.\n");
855 if (bdops->revalidate_disk)
856 bdops->revalidate_disk(bdev->bd_disk);
857 if (bdev->bd_disk->minors > 1)
858 bdev->bd_invalidated = 1;
862 EXPORT_SYMBOL(check_disk_change);
864 void bd_set_size(struct block_device *bdev, loff_t size)
866 unsigned bsize = bdev_hardsect_size(bdev);
868 bdev->bd_inode->i_size = size;
869 while (bsize < PAGE_CACHE_SIZE) {
874 bdev->bd_block_size = bsize;
875 bdev->bd_inode->i_blkbits = blksize_bits(bsize);
877 EXPORT_SYMBOL(bd_set_size);
879 static int do_open(struct block_device *bdev, struct file *file)
881 struct module *owner = NULL;
882 struct gendisk *disk;
886 file->f_mapping = bdev->bd_inode->i_mapping;
888 disk = get_gendisk(bdev->bd_dev, &part);
894 owner = disk->fops->owner;
896 mutex_lock(&bdev->bd_mutex);
897 if (!bdev->bd_openers) {
898 bdev->bd_disk = disk;
899 bdev->bd_contains = bdev;
901 struct backing_dev_info *bdi;
902 if (disk->fops->open) {
903 ret = disk->fops->open(bdev->bd_inode, file);
907 if (!bdev->bd_openers) {
908 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
909 bdi = blk_get_backing_dev_info(bdev);
911 bdi = &default_backing_dev_info;
912 bdev->bd_inode->i_data.backing_dev_info = bdi;
914 if (bdev->bd_invalidated)
915 rescan_partitions(disk, bdev);
918 struct block_device *whole;
919 whole = bdget_disk(disk, 0);
923 ret = blkdev_get(whole, file->f_mode, file->f_flags);
926 bdev->bd_contains = whole;
927 mutex_lock(&whole->bd_mutex);
928 whole->bd_part_count++;
929 p = disk->part[part - 1];
930 bdev->bd_inode->i_data.backing_dev_info =
931 whole->bd_inode->i_data.backing_dev_info;
932 if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) {
933 whole->bd_part_count--;
934 mutex_unlock(&whole->bd_mutex);
938 kobject_get(&p->kobj);
940 bd_set_size(bdev, (loff_t) p->nr_sects << 9);
941 mutex_unlock(&whole->bd_mutex);
946 if (bdev->bd_contains == bdev) {
947 if (bdev->bd_disk->fops->open) {
948 ret = bdev->bd_disk->fops->open(bdev->bd_inode, file);
952 if (bdev->bd_invalidated)
953 rescan_partitions(bdev->bd_disk, bdev);
955 mutex_lock(&bdev->bd_contains->bd_mutex);
956 bdev->bd_contains->bd_part_count++;
957 mutex_unlock(&bdev->bd_contains->bd_mutex);
961 mutex_unlock(&bdev->bd_mutex);
966 bdev->bd_disk = NULL;
967 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
968 if (bdev != bdev->bd_contains)
969 blkdev_put(bdev->bd_contains);
970 bdev->bd_contains = NULL;
974 mutex_unlock(&bdev->bd_mutex);
981 int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
984 * This crockload is due to bad choice of ->open() type.
986 * For now, block device ->open() routine must _not_
987 * examine anything in 'inode' argument except ->i_rdev.
989 struct file fake_file = {};
990 struct dentry fake_dentry = {};
991 fake_file.f_mode = mode;
992 fake_file.f_flags = flags;
993 fake_file.f_dentry = &fake_dentry;
994 fake_dentry.d_inode = bdev->bd_inode;
996 return do_open(bdev, &fake_file);
999 EXPORT_SYMBOL(blkdev_get);
1001 static int blkdev_open(struct inode * inode, struct file * filp)
1003 struct block_device *bdev;
1007 * Preserve backwards compatibility and allow large file access
1008 * even if userspace doesn't ask for it explicitly. Some mkfs
1009 * binary needs it. We might want to drop this workaround
1010 * during an unstable branch.
1012 filp->f_flags |= O_LARGEFILE;
1014 bdev = bd_acquire(inode);
1016 res = do_open(bdev, filp);
1020 if (!(filp->f_flags & O_EXCL) )
1023 if (!(res = bd_claim(bdev, filp)))
1030 int blkdev_put(struct block_device *bdev)
1033 struct inode *bd_inode = bdev->bd_inode;
1034 struct gendisk *disk = bdev->bd_disk;
1036 mutex_lock(&bdev->bd_mutex);
1038 if (!--bdev->bd_openers) {
1039 sync_blockdev(bdev);
1042 if (bdev->bd_contains == bdev) {
1043 if (disk->fops->release)
1044 ret = disk->fops->release(bd_inode, NULL);
1046 mutex_lock(&bdev->bd_contains->bd_mutex);
1047 bdev->bd_contains->bd_part_count--;
1048 mutex_unlock(&bdev->bd_contains->bd_mutex);
1050 if (!bdev->bd_openers) {
1051 struct module *owner = disk->fops->owner;
1056 if (bdev->bd_contains != bdev) {
1057 kobject_put(&bdev->bd_part->kobj);
1058 bdev->bd_part = NULL;
1060 bdev->bd_disk = NULL;
1061 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1062 if (bdev != bdev->bd_contains) {
1063 blkdev_put(bdev->bd_contains);
1065 bdev->bd_contains = NULL;
1068 mutex_unlock(&bdev->bd_mutex);
1073 EXPORT_SYMBOL(blkdev_put);
1075 static int blkdev_close(struct inode * inode, struct file * filp)
1077 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
1078 if (bdev->bd_holder == filp)
1080 return blkdev_put(bdev);
1083 static ssize_t blkdev_file_write(struct file *file, const char __user *buf,
1084 size_t count, loff_t *ppos)
1086 struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count };
1088 return generic_file_write_nolock(file, &local_iov, 1, ppos);
1091 static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf,
1092 size_t count, loff_t pos)
1094 struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count };
1096 return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
1099 static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
1101 return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
1104 const struct address_space_operations def_blk_aops = {
1105 .readpage = blkdev_readpage,
1106 .writepage = blkdev_writepage,
1107 .sync_page = block_sync_page,
1108 .prepare_write = blkdev_prepare_write,
1109 .commit_write = blkdev_commit_write,
1110 .writepages = generic_writepages,
1111 .direct_IO = blkdev_direct_IO,
1114 const struct file_operations def_blk_fops = {
1115 .open = blkdev_open,
1116 .release = blkdev_close,
1117 .llseek = block_llseek,
1118 .read = generic_file_read,
1119 .write = blkdev_file_write,
1120 .aio_read = generic_file_aio_read,
1121 .aio_write = blkdev_file_aio_write,
1122 .mmap = generic_file_mmap,
1123 .fsync = block_fsync,
1124 .unlocked_ioctl = block_ioctl,
1125 #ifdef CONFIG_COMPAT
1126 .compat_ioctl = compat_blkdev_ioctl,
1128 .readv = generic_file_readv,
1129 .writev = generic_file_write_nolock,
1130 .sendfile = generic_file_sendfile,
1131 .splice_read = generic_file_splice_read,
1132 .splice_write = generic_file_splice_write,
1135 int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
1138 mm_segment_t old_fs = get_fs();
1140 res = blkdev_ioctl(bdev->bd_inode, NULL, cmd, arg);
1145 EXPORT_SYMBOL(ioctl_by_bdev);
1148 * lookup_bdev - lookup a struct block_device by name
1150 * @path: special file representing the block device
1152 * Get a reference to the blockdevice at @path in the current
1153 * namespace if possible and return it. Return ERR_PTR(error)
1156 struct block_device *lookup_bdev(const char *path)
1158 struct block_device *bdev;
1159 struct inode *inode;
1160 struct nameidata nd;
1163 if (!path || !*path)
1164 return ERR_PTR(-EINVAL);
1166 error = path_lookup(path, LOOKUP_FOLLOW, &nd);
1168 return ERR_PTR(error);
1170 inode = nd.dentry->d_inode;
1172 if (!S_ISBLK(inode->i_mode))
1175 if (nd.mnt->mnt_flags & MNT_NODEV)
1178 bdev = bd_acquire(inode);
1185 bdev = ERR_PTR(error);
1190 * open_bdev_excl - open a block device by name and set it up for use
1192 * @path: special file representing the block device
1193 * @flags: %MS_RDONLY for opening read-only
1194 * @holder: owner for exclusion
1196 * Open the blockdevice described by the special file at @path, claim it
1199 struct block_device *open_bdev_excl(const char *path, int flags, void *holder)
1201 struct block_device *bdev;
1202 mode_t mode = FMODE_READ;
1205 bdev = lookup_bdev(path);
1209 if (!(flags & MS_RDONLY))
1210 mode |= FMODE_WRITE;
1211 error = blkdev_get(bdev, mode, 0);
1213 return ERR_PTR(error);
1215 if (!(flags & MS_RDONLY) && bdev_read_only(bdev))
1217 error = bd_claim(bdev, holder);
1225 return ERR_PTR(error);
1228 EXPORT_SYMBOL(open_bdev_excl);
1231 * close_bdev_excl - release a blockdevice openen by open_bdev_excl()
1233 * @bdev: blockdevice to close
1235 * This is the counterpart to open_bdev_excl().
1237 void close_bdev_excl(struct block_device *bdev)
1243 EXPORT_SYMBOL(close_bdev_excl);