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/writeback.h>
21 #include <linux/mpage.h>
22 #include <linux/mount.h>
23 #include <linux/uio.h>
24 #include <linux/namei.h>
25 #include <linux/log2.h>
26 #include <asm/uaccess.h>
30 struct block_device bdev;
31 struct inode vfs_inode;
34 static const struct address_space_operations def_blk_aops;
36 static inline struct bdev_inode *BDEV_I(struct inode *inode)
38 return container_of(inode, struct bdev_inode, vfs_inode);
41 inline struct block_device *I_BDEV(struct inode *inode)
43 return &BDEV_I(inode)->bdev;
46 EXPORT_SYMBOL(I_BDEV);
48 static sector_t max_block(struct block_device *bdev)
50 sector_t retval = ~((sector_t)0);
51 loff_t sz = i_size_read(bdev->bd_inode);
54 unsigned int size = block_size(bdev);
55 unsigned int sizebits = blksize_bits(size);
56 retval = (sz >> sizebits);
61 /* Kill _all_ buffers and pagecache , dirty or not.. */
62 static void kill_bdev(struct block_device *bdev)
64 if (bdev->bd_inode->i_mapping->nrpages == 0)
67 truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
70 int set_blocksize(struct block_device *bdev, int size)
72 /* Size must be a power of two, and between 512 and PAGE_SIZE */
73 if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
76 /* Size cannot be smaller than the size supported by the device */
77 if (size < bdev_hardsect_size(bdev))
80 /* Don't change the size if it is same as current */
81 if (bdev->bd_block_size != size) {
83 bdev->bd_block_size = size;
84 bdev->bd_inode->i_blkbits = blksize_bits(size);
90 EXPORT_SYMBOL(set_blocksize);
92 int sb_set_blocksize(struct super_block *sb, int size)
94 if (set_blocksize(sb->s_bdev, size))
96 /* If we get here, we know size is power of two
97 * and it's value is between 512 and PAGE_SIZE */
98 sb->s_blocksize = size;
99 sb->s_blocksize_bits = blksize_bits(size);
100 return sb->s_blocksize;
103 EXPORT_SYMBOL(sb_set_blocksize);
105 int sb_min_blocksize(struct super_block *sb, int size)
107 int minsize = bdev_hardsect_size(sb->s_bdev);
110 return sb_set_blocksize(sb, size);
113 EXPORT_SYMBOL(sb_min_blocksize);
116 blkdev_get_block(struct inode *inode, sector_t iblock,
117 struct buffer_head *bh, int create)
119 if (iblock >= max_block(I_BDEV(inode))) {
124 * for reads, we're just trying to fill a partial page.
125 * return a hole, they will have to call get_block again
126 * before they can fill it, and they will get -EIO at that
131 bh->b_bdev = I_BDEV(inode);
132 bh->b_blocknr = iblock;
133 set_buffer_mapped(bh);
138 blkdev_get_blocks(struct inode *inode, sector_t iblock,
139 struct buffer_head *bh, int create)
141 sector_t end_block = max_block(I_BDEV(inode));
142 unsigned long max_blocks = bh->b_size >> inode->i_blkbits;
144 if ((iblock + max_blocks) > end_block) {
145 max_blocks = end_block - iblock;
146 if ((long)max_blocks <= 0) {
148 return -EIO; /* write fully beyond EOF */
150 * It is a read which is fully beyond EOF. We return
151 * a !buffer_mapped buffer
157 bh->b_bdev = I_BDEV(inode);
158 bh->b_blocknr = iblock;
159 bh->b_size = max_blocks << inode->i_blkbits;
161 set_buffer_mapped(bh);
166 blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
167 loff_t offset, unsigned long nr_segs)
169 struct file *file = iocb->ki_filp;
170 struct inode *inode = file->f_mapping->host;
172 return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode),
173 iov, offset, nr_segs, blkdev_get_blocks, NULL);
177 static void blk_end_aio(struct bio *bio, int error)
179 struct kiocb *iocb = bio->bi_private;
180 atomic_t *bio_count = &iocb->ki_bio_count;
182 if (bio_data_dir(bio) == READ)
183 bio_check_pages_dirty(bio);
185 bio_release_pages(bio);
189 /* iocb->ki_nbytes stores error code from LLDD */
191 iocb->ki_nbytes = -EIO;
193 if (atomic_dec_and_test(bio_count)) {
194 if ((long)iocb->ki_nbytes < 0)
195 aio_complete(iocb, iocb->ki_nbytes, 0);
197 aio_complete(iocb, iocb->ki_left, 0);
207 struct page *page[VEC_SIZE];
210 #define PAGES_SPANNED(addr, len) \
211 (DIV_ROUND_UP((addr) + (len), PAGE_SIZE) - (addr) / PAGE_SIZE);
214 * get page pointer for user addr, we internally cache struct page array for
215 * (addr, count) range in pvec to avoid frequent call to get_user_pages. If
216 * internal page list is exhausted, a batch count of up to VEC_SIZE is used
217 * to get next set of page struct.
219 static struct page *blk_get_page(unsigned long addr, size_t count, int rw,
223 if (pvec->idx == pvec->nr) {
224 nr_pages = PAGES_SPANNED(addr, count);
225 nr_pages = min(nr_pages, VEC_SIZE);
226 down_read(¤t->mm->mmap_sem);
227 ret = get_user_pages(current, current->mm, addr, nr_pages,
228 rw == READ, 0, pvec->page, NULL);
229 up_read(¤t->mm->mmap_sem);
235 return pvec->page[pvec->idx++];
238 /* return a page back to pvec array */
239 static void blk_unget_page(struct page *page, struct pvec *pvec)
241 pvec->page[--pvec->idx] = page;
245 blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
246 loff_t pos, unsigned long nr_segs)
248 struct inode *inode = iocb->ki_filp->f_mapping->host;
249 unsigned blkbits = blksize_bits(bdev_hardsect_size(I_BDEV(inode)));
250 unsigned blocksize_mask = (1 << blkbits) - 1;
251 unsigned long seg = 0; /* iov segment iterator */
252 unsigned long nvec; /* number of bio vec needed */
253 unsigned long cur_off; /* offset into current page */
254 unsigned long cur_len; /* I/O len of current page, up to PAGE_SIZE */
256 unsigned long addr; /* user iovec address */
257 size_t count; /* user iovec len */
258 size_t nbytes = iocb->ki_nbytes = iocb->ki_left; /* total xfer size */
259 loff_t size; /* size of block device */
261 atomic_t *bio_count = &iocb->ki_bio_count;
268 if (pos & blocksize_mask)
271 size = i_size_read(inode);
272 if (pos + nbytes > size) {
274 iocb->ki_left = nbytes;
278 * check first non-zero iov alignment, the remaining
279 * iov alignment is checked inside bio loop below.
282 addr = (unsigned long) iov[seg].iov_base;
283 count = min(iov[seg].iov_len, nbytes);
284 if (addr & blocksize_mask || count & blocksize_mask)
286 } while (!count && ++seg < nr_segs);
287 atomic_set(bio_count, 1);
290 /* roughly estimate number of bio vec needed */
291 nvec = (nbytes + PAGE_SIZE - 1) / PAGE_SIZE;
292 nvec = max(nvec, nr_segs - seg);
293 nvec = min(nvec, (unsigned long) BIO_MAX_PAGES);
295 /* bio_alloc should not fail with GFP_KERNEL flag */
296 bio = bio_alloc(GFP_KERNEL, nvec);
297 bio->bi_bdev = I_BDEV(inode);
298 bio->bi_end_io = blk_end_aio;
299 bio->bi_private = iocb;
300 bio->bi_sector = pos >> blkbits;
302 cur_off = addr & ~PAGE_MASK;
303 cur_len = PAGE_SIZE - cur_off;
307 page = blk_get_page(addr, count, rw, &pvec);
308 if (unlikely(IS_ERR(page)))
311 if (bio_add_page(bio, page, cur_len, cur_off)) {
319 while (++seg < nr_segs) {
320 addr = (unsigned long) iov[seg].iov_base;
321 count = iov[seg].iov_len;
324 if (unlikely(addr & blocksize_mask ||
325 count & blocksize_mask)) {
326 page = ERR_PTR(-EINVAL);
329 count = min(count, nbytes);
333 blk_unget_page(page, &pvec);
336 /* bio is ready, submit it */
338 bio_set_pages_dirty(bio);
339 atomic_inc(bio_count);
344 iocb->ki_left -= nbytes;
345 nbytes = iocb->ki_left;
346 iocb->ki_pos += nbytes;
348 blk_run_address_space(inode->i_mapping);
349 if (atomic_dec_and_test(bio_count))
350 aio_complete(iocb, nbytes, 0);
356 * back out nbytes count constructed so far for this bio,
357 * we will throw away current bio.
359 nbytes += bio->bi_size;
360 bio_release_pages(bio);
364 * if no bio was submmitted, return the error code.
365 * otherwise, proceed with pending I/O completion.
367 if (atomic_read(bio_count) == 1)
368 return PTR_ERR(page);
373 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
375 return block_write_full_page(page, blkdev_get_block, wbc);
378 static int blkdev_readpage(struct file * file, struct page * page)
380 return block_read_full_page(page, blkdev_get_block);
383 static int blkdev_write_begin(struct file *file, struct address_space *mapping,
384 loff_t pos, unsigned len, unsigned flags,
385 struct page **pagep, void **fsdata)
388 return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
392 static int blkdev_write_end(struct file *file, struct address_space *mapping,
393 loff_t pos, unsigned len, unsigned copied,
394 struct page *page, void *fsdata)
397 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
400 page_cache_release(page);
407 * for a block special file file->f_path.dentry->d_inode->i_size is zero
408 * so we compute the size by hand (just as in block_read/write above)
410 static loff_t block_llseek(struct file *file, loff_t offset, int origin)
412 struct inode *bd_inode = file->f_mapping->host;
416 mutex_lock(&bd_inode->i_mutex);
417 size = i_size_read(bd_inode);
424 offset += file->f_pos;
427 if (offset >= 0 && offset <= size) {
428 if (offset != file->f_pos) {
429 file->f_pos = offset;
433 mutex_unlock(&bd_inode->i_mutex);
438 * Filp is never NULL; the only case when ->fsync() is called with
439 * NULL first argument is nfsd_sync_dir() and that's not a directory.
442 static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
444 return sync_blockdev(I_BDEV(filp->f_mapping->host));
451 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
452 static struct kmem_cache * bdev_cachep __read_mostly;
454 static struct inode *bdev_alloc_inode(struct super_block *sb)
456 struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
459 return &ei->vfs_inode;
462 static void bdev_destroy_inode(struct inode *inode)
464 struct bdev_inode *bdi = BDEV_I(inode);
466 bdi->bdev.bd_inode_backing_dev_info = NULL;
467 kmem_cache_free(bdev_cachep, bdi);
470 static void init_once(struct kmem_cache * cachep, void *foo)
472 struct bdev_inode *ei = (struct bdev_inode *) foo;
473 struct block_device *bdev = &ei->bdev;
475 memset(bdev, 0, sizeof(*bdev));
476 mutex_init(&bdev->bd_mutex);
477 sema_init(&bdev->bd_mount_sem, 1);
478 INIT_LIST_HEAD(&bdev->bd_inodes);
479 INIT_LIST_HEAD(&bdev->bd_list);
481 INIT_LIST_HEAD(&bdev->bd_holder_list);
483 inode_init_once(&ei->vfs_inode);
486 static inline void __bd_forget(struct inode *inode)
488 list_del_init(&inode->i_devices);
489 inode->i_bdev = NULL;
490 inode->i_mapping = &inode->i_data;
493 static void bdev_clear_inode(struct inode *inode)
495 struct block_device *bdev = &BDEV_I(inode)->bdev;
497 spin_lock(&bdev_lock);
498 while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
499 __bd_forget(list_entry(p, struct inode, i_devices));
501 list_del_init(&bdev->bd_list);
502 spin_unlock(&bdev_lock);
505 static const struct super_operations bdev_sops = {
506 .statfs = simple_statfs,
507 .alloc_inode = bdev_alloc_inode,
508 .destroy_inode = bdev_destroy_inode,
509 .drop_inode = generic_delete_inode,
510 .clear_inode = bdev_clear_inode,
513 static int bd_get_sb(struct file_system_type *fs_type,
514 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
516 return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
519 static struct file_system_type bd_type = {
522 .kill_sb = kill_anon_super,
525 static struct vfsmount *bd_mnt __read_mostly;
526 struct super_block *blockdev_superblock;
528 void __init bdev_cache_init(void)
531 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
532 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
533 SLAB_MEM_SPREAD|SLAB_PANIC),
535 err = register_filesystem(&bd_type);
537 panic("Cannot register bdev pseudo-fs");
538 bd_mnt = kern_mount(&bd_type);
540 panic("Cannot create bdev pseudo-fs");
541 blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
545 * Most likely _very_ bad one - but then it's hardly critical for small
546 * /dev and can be fixed when somebody will need really large one.
547 * Keep in mind that it will be fed through icache hash function too.
549 static inline unsigned long hash(dev_t dev)
551 return MAJOR(dev)+MINOR(dev);
554 static int bdev_test(struct inode *inode, void *data)
556 return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
559 static int bdev_set(struct inode *inode, void *data)
561 BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
565 static LIST_HEAD(all_bdevs);
567 struct block_device *bdget(dev_t dev)
569 struct block_device *bdev;
572 inode = iget5_locked(bd_mnt->mnt_sb, hash(dev),
573 bdev_test, bdev_set, &dev);
578 bdev = &BDEV_I(inode)->bdev;
580 if (inode->i_state & I_NEW) {
581 bdev->bd_contains = NULL;
582 bdev->bd_inode = inode;
583 bdev->bd_block_size = (1 << inode->i_blkbits);
584 bdev->bd_part_count = 0;
585 bdev->bd_invalidated = 0;
586 inode->i_mode = S_IFBLK;
588 inode->i_bdev = bdev;
589 inode->i_data.a_ops = &def_blk_aops;
590 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
591 inode->i_data.backing_dev_info = &default_backing_dev_info;
592 spin_lock(&bdev_lock);
593 list_add(&bdev->bd_list, &all_bdevs);
594 spin_unlock(&bdev_lock);
595 unlock_new_inode(inode);
600 EXPORT_SYMBOL(bdget);
602 long nr_blockdev_pages(void)
604 struct block_device *bdev;
606 spin_lock(&bdev_lock);
607 list_for_each_entry(bdev, &all_bdevs, bd_list) {
608 ret += bdev->bd_inode->i_mapping->nrpages;
610 spin_unlock(&bdev_lock);
614 void bdput(struct block_device *bdev)
616 iput(bdev->bd_inode);
619 EXPORT_SYMBOL(bdput);
621 static struct block_device *bd_acquire(struct inode *inode)
623 struct block_device *bdev;
625 spin_lock(&bdev_lock);
626 bdev = inode->i_bdev;
628 atomic_inc(&bdev->bd_inode->i_count);
629 spin_unlock(&bdev_lock);
632 spin_unlock(&bdev_lock);
634 bdev = bdget(inode->i_rdev);
636 spin_lock(&bdev_lock);
637 if (!inode->i_bdev) {
639 * We take an additional bd_inode->i_count for inode,
640 * and it's released in clear_inode() of inode.
641 * So, we can access it via ->i_mapping always
644 atomic_inc(&bdev->bd_inode->i_count);
645 inode->i_bdev = bdev;
646 inode->i_mapping = bdev->bd_inode->i_mapping;
647 list_add(&inode->i_devices, &bdev->bd_inodes);
649 spin_unlock(&bdev_lock);
654 /* Call when you free inode */
656 void bd_forget(struct inode *inode)
658 struct block_device *bdev = NULL;
660 spin_lock(&bdev_lock);
662 if (inode->i_sb != blockdev_superblock)
663 bdev = inode->i_bdev;
666 spin_unlock(&bdev_lock);
669 iput(bdev->bd_inode);
672 int bd_claim(struct block_device *bdev, void *holder)
675 spin_lock(&bdev_lock);
677 /* first decide result */
678 if (bdev->bd_holder == holder)
679 res = 0; /* already a holder */
680 else if (bdev->bd_holder != NULL)
681 res = -EBUSY; /* held by someone else */
682 else if (bdev->bd_contains == bdev)
683 res = 0; /* is a whole device which isn't held */
685 else if (bdev->bd_contains->bd_holder == bd_claim)
686 res = 0; /* is a partition of a device that is being partitioned */
687 else if (bdev->bd_contains->bd_holder != NULL)
688 res = -EBUSY; /* is a partition of a held device */
690 res = 0; /* is a partition of an un-held device */
692 /* now impose change */
694 /* note that for a whole device bd_holders
695 * will be incremented twice, and bd_holder will
696 * be set to bd_claim before being set to holder
698 bdev->bd_contains->bd_holders ++;
699 bdev->bd_contains->bd_holder = bd_claim;
701 bdev->bd_holder = holder;
703 spin_unlock(&bdev_lock);
707 EXPORT_SYMBOL(bd_claim);
709 void bd_release(struct block_device *bdev)
711 spin_lock(&bdev_lock);
712 if (!--bdev->bd_contains->bd_holders)
713 bdev->bd_contains->bd_holder = NULL;
714 if (!--bdev->bd_holders)
715 bdev->bd_holder = NULL;
716 spin_unlock(&bdev_lock);
719 EXPORT_SYMBOL(bd_release);
723 * Functions for bd_claim_by_kobject / bd_release_from_kobject
725 * If a kobject is passed to bd_claim_by_kobject()
726 * and the kobject has a parent directory,
727 * following symlinks are created:
728 * o from the kobject to the claimed bdev
729 * o from "holders" directory of the bdev to the parent of the kobject
730 * bd_release_from_kobject() removes these symlinks.
733 * If /dev/dm-0 maps to /dev/sda, kobject corresponding to
734 * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
735 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
736 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
739 static struct kobject *bdev_get_kobj(struct block_device *bdev)
741 if (bdev->bd_contains != bdev)
742 return kobject_get(&bdev->bd_part->dev.kobj);
744 return kobject_get(&bdev->bd_disk->dev.kobj);
747 static struct kobject *bdev_get_holder(struct block_device *bdev)
749 if (bdev->bd_contains != bdev)
750 return kobject_get(bdev->bd_part->holder_dir);
752 return kobject_get(bdev->bd_disk->holder_dir);
755 static int add_symlink(struct kobject *from, struct kobject *to)
759 return sysfs_create_link(from, to, kobject_name(to));
762 static void del_symlink(struct kobject *from, struct kobject *to)
766 sysfs_remove_link(from, kobject_name(to));
770 * 'struct bd_holder' contains pointers to kobjects symlinked by
771 * bd_claim_by_kobject.
772 * It's connected to bd_holder_list which is protected by bdev->bd_sem.
775 struct list_head list; /* chain of holders of the bdev */
776 int count; /* references from the holder */
777 struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */
778 struct kobject *hdev; /* e.g. "/block/dm-0" */
779 struct kobject *hdir; /* e.g. "/block/sda/holders" */
780 struct kobject *sdev; /* e.g. "/block/sda" */
784 * Get references of related kobjects at once.
785 * Returns 1 on success. 0 on failure.
787 * Should call bd_holder_release_dirs() after successful use.
789 static int bd_holder_grab_dirs(struct block_device *bdev,
790 struct bd_holder *bo)
795 bo->sdir = kobject_get(bo->sdir);
799 bo->hdev = kobject_get(bo->sdir->parent);
803 bo->sdev = bdev_get_kobj(bdev);
807 bo->hdir = bdev_get_holder(bdev);
814 kobject_put(bo->sdev);
816 kobject_put(bo->hdev);
818 kobject_put(bo->sdir);
823 /* Put references of related kobjects at once. */
824 static void bd_holder_release_dirs(struct bd_holder *bo)
826 kobject_put(bo->hdir);
827 kobject_put(bo->sdev);
828 kobject_put(bo->hdev);
829 kobject_put(bo->sdir);
832 static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
834 struct bd_holder *bo;
836 bo = kzalloc(sizeof(*bo), GFP_KERNEL);
846 static void free_bd_holder(struct bd_holder *bo)
852 * find_bd_holder - find matching struct bd_holder from the block device
854 * @bdev: struct block device to be searched
855 * @bo: target struct bd_holder
857 * Returns matching entry with @bo in @bdev->bd_holder_list.
858 * If found, increment the reference count and return the pointer.
859 * If not found, returns NULL.
861 static struct bd_holder *find_bd_holder(struct block_device *bdev,
862 struct bd_holder *bo)
864 struct bd_holder *tmp;
866 list_for_each_entry(tmp, &bdev->bd_holder_list, list)
867 if (tmp->sdir == bo->sdir) {
876 * add_bd_holder - create sysfs symlinks for bd_claim() relationship
878 * @bdev: block device to be bd_claimed
879 * @bo: preallocated and initialized by alloc_bd_holder()
881 * Add @bo to @bdev->bd_holder_list, create symlinks.
883 * Returns 0 if symlinks are created.
884 * Returns -ve if something fails.
886 static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
893 if (!bd_holder_grab_dirs(bdev, bo))
896 err = add_symlink(bo->sdir, bo->sdev);
900 err = add_symlink(bo->hdir, bo->hdev);
902 del_symlink(bo->sdir, bo->sdev);
906 list_add_tail(&bo->list, &bdev->bd_holder_list);
911 * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
913 * @bdev: block device to be bd_claimed
914 * @kobj: holder's kobject
916 * If there is matching entry with @kobj in @bdev->bd_holder_list
917 * and no other bd_claim() from the same kobject,
918 * remove the struct bd_holder from the list, delete symlinks for it.
920 * Returns a pointer to the struct bd_holder when it's removed from the list
921 * and ready to be freed.
922 * Returns NULL if matching claim isn't found or there is other bd_claim()
923 * by the same kobject.
925 static struct bd_holder *del_bd_holder(struct block_device *bdev,
926 struct kobject *kobj)
928 struct bd_holder *bo;
930 list_for_each_entry(bo, &bdev->bd_holder_list, list) {
931 if (bo->sdir == kobj) {
933 BUG_ON(bo->count < 0);
936 del_symlink(bo->sdir, bo->sdev);
937 del_symlink(bo->hdir, bo->hdev);
938 bd_holder_release_dirs(bo);
949 * bd_claim_by_kobject - bd_claim() with additional kobject signature
951 * @bdev: block device to be claimed
952 * @holder: holder's signature
953 * @kobj: holder's kobject
955 * Do bd_claim() and if it succeeds, create sysfs symlinks between
956 * the bdev and the holder's kobject.
957 * Use bd_release_from_kobject() when relesing the claimed bdev.
959 * Returns 0 on success. (same as bd_claim())
960 * Returns errno on failure.
962 static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
963 struct kobject *kobj)
966 struct bd_holder *bo, *found;
971 bo = alloc_bd_holder(kobj);
975 mutex_lock(&bdev->bd_mutex);
977 err = bd_claim(bdev, holder);
981 found = find_bd_holder(bdev, bo);
985 err = add_bd_holder(bdev, bo);
991 mutex_unlock(&bdev->bd_mutex);
997 * bd_release_from_kobject - bd_release() with additional kobject signature
999 * @bdev: block device to be released
1000 * @kobj: holder's kobject
1002 * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
1004 static void bd_release_from_kobject(struct block_device *bdev,
1005 struct kobject *kobj)
1010 mutex_lock(&bdev->bd_mutex);
1012 free_bd_holder(del_bd_holder(bdev, kobj));
1013 mutex_unlock(&bdev->bd_mutex);
1017 * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
1019 * @bdev: block device to be claimed
1020 * @holder: holder's signature
1021 * @disk: holder's gendisk
1023 * Call bd_claim_by_kobject() with getting @disk->slave_dir.
1025 int bd_claim_by_disk(struct block_device *bdev, void *holder,
1026 struct gendisk *disk)
1028 return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
1030 EXPORT_SYMBOL_GPL(bd_claim_by_disk);
1033 * bd_release_from_disk - wrapper function for bd_release_from_kobject()
1035 * @bdev: block device to be claimed
1036 * @disk: holder's gendisk
1038 * Call bd_release_from_kobject() and put @disk->slave_dir.
1040 void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
1042 bd_release_from_kobject(bdev, disk->slave_dir);
1043 kobject_put(disk->slave_dir);
1045 EXPORT_SYMBOL_GPL(bd_release_from_disk);
1049 * Tries to open block device by device number. Use it ONLY if you
1050 * really do not have anything better - i.e. when you are behind a
1051 * truly sucky interface and all you are given is a device number. _Never_
1052 * to be used for internal purposes. If you ever need it - reconsider
1055 struct block_device *open_by_devnum(dev_t dev, unsigned mode)
1057 struct block_device *bdev = bdget(dev);
1059 int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY;
1061 err = blkdev_get(bdev, mode, flags);
1062 return err ? ERR_PTR(err) : bdev;
1065 EXPORT_SYMBOL(open_by_devnum);
1068 * This routine checks whether a removable media has been changed,
1069 * and invalidates all buffer-cache-entries in that case. This
1070 * is a relatively slow routine, so we have to try to minimize using
1071 * it. Thus it is called only upon a 'mount' or 'open'. This
1072 * is the best way of combining speed and utility, I think.
1073 * People changing diskettes in the middle of an operation deserve
1076 int check_disk_change(struct block_device *bdev)
1078 struct gendisk *disk = bdev->bd_disk;
1079 struct block_device_operations * bdops = disk->fops;
1081 if (!bdops->media_changed)
1083 if (!bdops->media_changed(bdev->bd_disk))
1086 if (__invalidate_device(bdev))
1087 printk("VFS: busy inodes on changed media.\n");
1089 if (bdops->revalidate_disk)
1090 bdops->revalidate_disk(bdev->bd_disk);
1091 if (bdev->bd_disk->minors > 1)
1092 bdev->bd_invalidated = 1;
1096 EXPORT_SYMBOL(check_disk_change);
1098 void bd_set_size(struct block_device *bdev, loff_t size)
1100 unsigned bsize = bdev_hardsect_size(bdev);
1102 bdev->bd_inode->i_size = size;
1103 while (bsize < PAGE_CACHE_SIZE) {
1108 bdev->bd_block_size = bsize;
1109 bdev->bd_inode->i_blkbits = blksize_bits(bsize);
1111 EXPORT_SYMBOL(bd_set_size);
1113 static int __blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags,
1115 static int __blkdev_put(struct block_device *bdev, int for_part);
1120 * mutex_lock(part->bd_mutex)
1121 * mutex_lock_nested(whole->bd_mutex, 1)
1124 static int do_open(struct block_device *bdev, struct file *file, int for_part)
1126 struct module *owner = NULL;
1127 struct gendisk *disk;
1131 file->f_mapping = bdev->bd_inode->i_mapping;
1133 disk = get_gendisk(bdev->bd_dev, &part);
1139 owner = disk->fops->owner;
1141 mutex_lock_nested(&bdev->bd_mutex, for_part);
1142 if (!bdev->bd_openers) {
1143 bdev->bd_disk = disk;
1144 bdev->bd_contains = bdev;
1146 struct backing_dev_info *bdi;
1147 if (disk->fops->open) {
1148 ret = disk->fops->open(bdev->bd_inode, file);
1152 if (!bdev->bd_openers) {
1153 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
1154 bdi = blk_get_backing_dev_info(bdev);
1156 bdi = &default_backing_dev_info;
1157 bdev->bd_inode->i_data.backing_dev_info = bdi;
1159 if (bdev->bd_invalidated)
1160 rescan_partitions(disk, bdev);
1162 struct hd_struct *p;
1163 struct block_device *whole;
1164 whole = bdget_disk(disk, 0);
1169 ret = __blkdev_get(whole, file->f_mode, file->f_flags, 1);
1172 bdev->bd_contains = whole;
1173 p = disk->part[part - 1];
1174 bdev->bd_inode->i_data.backing_dev_info =
1175 whole->bd_inode->i_data.backing_dev_info;
1176 if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) {
1180 kobject_get(&p->dev.kobj);
1182 bd_set_size(bdev, (loff_t) p->nr_sects << 9);
1187 if (bdev->bd_contains == bdev) {
1188 if (bdev->bd_disk->fops->open) {
1189 ret = bdev->bd_disk->fops->open(bdev->bd_inode, file);
1193 if (bdev->bd_invalidated)
1194 rescan_partitions(bdev->bd_disk, bdev);
1199 bdev->bd_part_count++;
1200 mutex_unlock(&bdev->bd_mutex);
1205 bdev->bd_disk = NULL;
1206 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1207 if (bdev != bdev->bd_contains)
1208 __blkdev_put(bdev->bd_contains, 1);
1209 bdev->bd_contains = NULL;
1213 mutex_unlock(&bdev->bd_mutex);
1220 static int __blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags,
1224 * This crockload is due to bad choice of ->open() type.
1226 * For now, block device ->open() routine must _not_
1227 * examine anything in 'inode' argument except ->i_rdev.
1229 struct file fake_file = {};
1230 struct dentry fake_dentry = {};
1231 fake_file.f_mode = mode;
1232 fake_file.f_flags = flags;
1233 fake_file.f_path.dentry = &fake_dentry;
1234 fake_dentry.d_inode = bdev->bd_inode;
1236 return do_open(bdev, &fake_file, for_part);
1239 int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
1241 return __blkdev_get(bdev, mode, flags, 0);
1243 EXPORT_SYMBOL(blkdev_get);
1245 static int blkdev_open(struct inode * inode, struct file * filp)
1247 struct block_device *bdev;
1251 * Preserve backwards compatibility and allow large file access
1252 * even if userspace doesn't ask for it explicitly. Some mkfs
1253 * binary needs it. We might want to drop this workaround
1254 * during an unstable branch.
1256 filp->f_flags |= O_LARGEFILE;
1258 bdev = bd_acquire(inode);
1262 res = do_open(bdev, filp, 0);
1266 if (!(filp->f_flags & O_EXCL) )
1269 if (!(res = bd_claim(bdev, filp)))
1276 static int __blkdev_put(struct block_device *bdev, int for_part)
1279 struct inode *bd_inode = bdev->bd_inode;
1280 struct gendisk *disk = bdev->bd_disk;
1281 struct block_device *victim = NULL;
1283 mutex_lock_nested(&bdev->bd_mutex, for_part);
1286 bdev->bd_part_count--;
1288 if (!--bdev->bd_openers) {
1289 sync_blockdev(bdev);
1292 if (bdev->bd_contains == bdev) {
1293 if (disk->fops->release)
1294 ret = disk->fops->release(bd_inode, NULL);
1296 if (!bdev->bd_openers) {
1297 struct module *owner = disk->fops->owner;
1302 if (bdev->bd_contains != bdev) {
1303 kobject_put(&bdev->bd_part->dev.kobj);
1304 bdev->bd_part = NULL;
1306 bdev->bd_disk = NULL;
1307 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1308 if (bdev != bdev->bd_contains)
1309 victim = bdev->bd_contains;
1310 bdev->bd_contains = NULL;
1313 mutex_unlock(&bdev->bd_mutex);
1316 __blkdev_put(victim, 1);
1320 int blkdev_put(struct block_device *bdev)
1322 return __blkdev_put(bdev, 0);
1324 EXPORT_SYMBOL(blkdev_put);
1326 static int blkdev_close(struct inode * inode, struct file * filp)
1328 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
1329 if (bdev->bd_holder == filp)
1331 return blkdev_put(bdev);
1334 static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
1336 return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
1339 static const struct address_space_operations def_blk_aops = {
1340 .readpage = blkdev_readpage,
1341 .writepage = blkdev_writepage,
1342 .sync_page = block_sync_page,
1343 .write_begin = blkdev_write_begin,
1344 .write_end = blkdev_write_end,
1345 .writepages = generic_writepages,
1346 .direct_IO = blkdev_direct_IO,
1349 const struct file_operations def_blk_fops = {
1350 .open = blkdev_open,
1351 .release = blkdev_close,
1352 .llseek = block_llseek,
1353 .read = do_sync_read,
1354 .write = do_sync_write,
1355 .aio_read = generic_file_aio_read,
1356 .aio_write = generic_file_aio_write_nolock,
1357 .mmap = generic_file_mmap,
1358 .fsync = block_fsync,
1359 .unlocked_ioctl = block_ioctl,
1360 #ifdef CONFIG_COMPAT
1361 .compat_ioctl = compat_blkdev_ioctl,
1363 .splice_read = generic_file_splice_read,
1364 .splice_write = generic_file_splice_write,
1367 int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
1370 mm_segment_t old_fs = get_fs();
1372 res = blkdev_ioctl(bdev->bd_inode, NULL, cmd, arg);
1377 EXPORT_SYMBOL(ioctl_by_bdev);
1380 * lookup_bdev - lookup a struct block_device by name
1382 * @path: special file representing the block device
1384 * Get a reference to the blockdevice at @path in the current
1385 * namespace if possible and return it. Return ERR_PTR(error)
1388 struct block_device *lookup_bdev(const char *path)
1390 struct block_device *bdev;
1391 struct inode *inode;
1392 struct nameidata nd;
1395 if (!path || !*path)
1396 return ERR_PTR(-EINVAL);
1398 error = path_lookup(path, LOOKUP_FOLLOW, &nd);
1400 return ERR_PTR(error);
1402 inode = nd.path.dentry->d_inode;
1404 if (!S_ISBLK(inode->i_mode))
1407 if (nd.path.mnt->mnt_flags & MNT_NODEV)
1410 bdev = bd_acquire(inode);
1417 bdev = ERR_PTR(error);
1422 * open_bdev_excl - open a block device by name and set it up for use
1424 * @path: special file representing the block device
1425 * @flags: %MS_RDONLY for opening read-only
1426 * @holder: owner for exclusion
1428 * Open the blockdevice described by the special file at @path, claim it
1431 struct block_device *open_bdev_excl(const char *path, int flags, void *holder)
1433 struct block_device *bdev;
1434 mode_t mode = FMODE_READ;
1437 bdev = lookup_bdev(path);
1441 if (!(flags & MS_RDONLY))
1442 mode |= FMODE_WRITE;
1443 error = blkdev_get(bdev, mode, 0);
1445 return ERR_PTR(error);
1447 if (!(flags & MS_RDONLY) && bdev_read_only(bdev))
1449 error = bd_claim(bdev, holder);
1457 return ERR_PTR(error);
1460 EXPORT_SYMBOL(open_bdev_excl);
1463 * close_bdev_excl - release a blockdevice openen by open_bdev_excl()
1465 * @bdev: blockdevice to close
1467 * This is the counterpart to open_bdev_excl().
1469 void close_bdev_excl(struct block_device *bdev)
1475 EXPORT_SYMBOL(close_bdev_excl);
1477 int __invalidate_device(struct block_device *bdev)
1479 struct super_block *sb = get_super(bdev);
1484 * no need to lock the super, get_super holds the
1485 * read mutex so the filesystem cannot go away
1486 * under us (->put_super runs with the write lock
1489 shrink_dcache_sb(sb);
1490 res = invalidate_inodes(sb);
1493 invalidate_bdev(bdev);
1496 EXPORT_SYMBOL(__invalidate_device);