diff options
Diffstat (limited to 'fs/block_dev.c')
-rw-r--r-- | fs/block_dev.c | 177 |
1 files changed, 101 insertions, 76 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 6d6e4d50834c..b350ed3af83b 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -863,31 +863,46 @@ void __init bdev_cache_init(void) blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ } -static struct block_device *bdget(dev_t dev) +struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) { struct block_device *bdev; struct inode *inode; - inode = iget_locked(blockdev_superblock, dev); + inode = new_inode(blockdev_superblock); if (!inode) return NULL; + inode->i_mode = S_IFBLK; + inode->i_rdev = 0; + inode->i_data.a_ops = &def_blk_aops; + mapping_set_gfp_mask(&inode->i_data, GFP_USER); + + bdev = I_BDEV(inode); + spin_lock_init(&bdev->bd_size_lock); + bdev->bd_disk = disk; + bdev->bd_partno = partno; + bdev->bd_contains = NULL; + bdev->bd_super = NULL; + bdev->bd_inode = inode; + bdev->bd_part_count = 0; + return bdev; +} - bdev = &BDEV_I(inode)->bdev; +void bdev_add(struct block_device *bdev, dev_t dev) +{ + bdev->bd_dev = dev; + bdev->bd_inode->i_rdev = dev; + bdev->bd_inode->i_ino = dev; + insert_inode_hash(bdev->bd_inode); +} - if (inode->i_state & I_NEW) { - spin_lock_init(&bdev->bd_size_lock); - bdev->bd_contains = NULL; - bdev->bd_super = NULL; - bdev->bd_inode = inode; - bdev->bd_part_count = 0; - bdev->bd_dev = dev; - inode->i_mode = S_IFBLK; - inode->i_rdev = dev; - inode->i_data.a_ops = &def_blk_aops; - mapping_set_gfp_mask(&inode->i_data, GFP_USER); - unlock_new_inode(inode); - } - return bdev; +static struct block_device *bdget(dev_t dev) +{ + struct inode *inode; + + inode = ilookup(blockdev_superblock, dev); + if (!inode) + return NULL; + return &BDEV_I(inode)->bdev; } /** @@ -1004,27 +1019,6 @@ retry: } EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */ -static struct gendisk *bdev_get_gendisk(struct block_device *bdev, int *partno) -{ - struct gendisk *disk = get_gendisk(bdev->bd_dev, partno); - - if (!disk) - return NULL; - /* - * Now that we hold gendisk reference we make sure bdev we looked up is - * not stale. If it is, it means device got removed and created before - * we looked up gendisk and we fail open in such case. Associating - * unhashed bdev with newly created gendisk could lead to two bdevs - * (and thus two independent caches) being associated with one device - * which is bad. - */ - if (inode_unhashed(bdev->bd_inode)) { - put_disk_and_module(disk); - return NULL; - } - return disk; -} - static void bd_clear_claiming(struct block_device *whole, void *holder) { lockdep_assert_held(&bdev_lock); @@ -1347,19 +1341,17 @@ EXPORT_SYMBOL_GPL(bdev_disk_changed); * mutex_lock(part->bd_mutex) * mutex_lock_nested(whole->bd_mutex, 1) */ -static int __blkdev_get(struct block_device *bdev, struct gendisk *disk, - int partno, fmode_t mode) +static int __blkdev_get(struct block_device *bdev, fmode_t mode) { + struct gendisk *disk = bdev->bd_disk; int ret; if (!bdev->bd_openers) { - bdev->bd_disk = disk; bdev->bd_contains = bdev; - bdev->bd_partno = partno; - if (!partno) { + if (!bdev->bd_partno) { ret = -ENXIO; - bdev->bd_part = disk_get_part(disk, partno); + bdev->bd_part = disk_get_part(disk, 0); if (!bdev->bd_part) goto out_clear; @@ -1388,7 +1380,7 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk, struct block_device *whole = bdget_disk(disk, 0); mutex_lock_nested(&whole->bd_mutex, 1); - ret = __blkdev_get(whole, disk, 0, mode); + ret = __blkdev_get(whole, mode); if (ret) { mutex_unlock(&whole->bd_mutex); bdput(whole); @@ -1398,7 +1390,7 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk, mutex_unlock(&whole->bd_mutex); bdev->bd_contains = whole; - bdev->bd_part = disk_get_part(disk, partno); + bdev->bd_part = disk_get_part(disk, bdev->bd_partno); if (!(disk->flags & GENHD_FL_UP) || !bdev->bd_part || !bdev->bd_part->nr_sects) { __blkdev_put(whole, mode, 1); @@ -1430,12 +1422,53 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk, out_clear: disk_put_part(bdev->bd_part); - bdev->bd_disk = NULL; bdev->bd_part = NULL; bdev->bd_contains = NULL; return ret; } +struct block_device *blkdev_get_no_open(dev_t dev) +{ + struct block_device *bdev; + struct gendisk *disk; + + down_read(&bdev_lookup_sem); + bdev = bdget(dev); + if (!bdev) { + up_read(&bdev_lookup_sem); + blk_request_module(dev); + down_read(&bdev_lookup_sem); + + bdev = bdget(dev); + if (!bdev) + goto unlock; + } + + disk = bdev->bd_disk; + if (!kobject_get_unless_zero(&disk_to_dev(disk)->kobj)) + goto bdput; + if ((disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP) + goto put_disk; + if (!try_module_get(bdev->bd_disk->fops->owner)) + goto put_disk; + up_read(&bdev_lookup_sem); + return bdev; +put_disk: + put_disk(disk); +bdput: + bdput(bdev); +unlock: + up_read(&bdev_lookup_sem); + return NULL; +} + +void blkdev_put_no_open(struct block_device *bdev) +{ + module_put(bdev->bd_disk->fops->owner); + put_disk(bdev->bd_disk); + bdput(bdev); +} + /** * blkdev_get_by_dev - open a block device by device number * @dev: device number of block device to open @@ -1463,7 +1496,6 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) bool unblock_events = true; struct block_device *bdev; struct gendisk *disk; - int partno; int ret; ret = devcgroup_check_permission(DEVCG_DEV_BLOCK, @@ -1473,18 +1505,14 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) if (ret) return ERR_PTR(ret); - bdev = bdget(dev); - if (!bdev) - return ERR_PTR(-ENOMEM); - /* * If we lost a race with 'disk' being deleted, try again. See md.c. */ retry: - ret = -ENXIO; - disk = bdev_get_gendisk(bdev, &partno); - if (!disk) - goto bdput; + bdev = blkdev_get_no_open(dev); + if (!bdev) + return ERR_PTR(-ENXIO); + disk = bdev->bd_disk; if (mode & FMODE_EXCL) { WARN_ON_ONCE(!holder); @@ -1492,7 +1520,7 @@ retry: ret = -ENOMEM; claiming = bdget_disk(disk, 0); if (!claiming) - goto put_disk; + goto put_blkdev; ret = bd_prepare_to_claim(bdev, claiming, holder); if (ret) goto put_claiming; @@ -1501,12 +1529,10 @@ retry: disk_block_events(disk); mutex_lock(&bdev->bd_mutex); - ret =__blkdev_get(bdev, disk, partno, mode); - if (!(mode & FMODE_EXCL)) { - ; /* nothing to do here */ - } else if (ret) { - bd_abort_claiming(bdev, claiming, holder); - } else { + ret =__blkdev_get(bdev, mode); + if (ret) + goto abort_claiming; + if (mode & FMODE_EXCL) { bd_finish_claiming(bdev, claiming, holder); /* @@ -1526,21 +1552,23 @@ retry: if (unblock_events) disk_unblock_events(disk); + if (mode & FMODE_EXCL) + bdput(claiming); + return bdev; +abort_claiming: + if (mode & FMODE_EXCL) + bd_abort_claiming(bdev, claiming, holder); + mutex_unlock(&bdev->bd_mutex); + disk_unblock_events(disk); put_claiming: if (mode & FMODE_EXCL) bdput(claiming); -put_disk: - if (ret) - put_disk_and_module(disk); +put_blkdev: + blkdev_put_no_open(bdev); if (ret == -ERESTARTSYS) goto retry; -bdput: - if (ret) { - bdput(bdev); - return ERR_PTR(ret); - } - return bdev; + return ERR_PTR(ret); } EXPORT_SYMBOL(blkdev_get_by_dev); @@ -1641,7 +1669,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) disk_put_part(bdev->bd_part); bdev->bd_part = NULL; - bdev->bd_disk = NULL; if (bdev_is_partition(bdev)) victim = bdev->bd_contains; bdev->bd_contains = NULL; @@ -1699,12 +1726,10 @@ void blkdev_put(struct block_device *bdev, fmode_t mode) * from userland - e.g. eject(1). */ disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); - mutex_unlock(&bdev->bd_mutex); __blkdev_put(bdev, mode, 0); - bdput(bdev); - put_disk_and_module(disk); + blkdev_put_no_open(bdev); } EXPORT_SYMBOL(blkdev_put); |