diff options
| -rw-r--r-- | drivers/block/loop.c | 16 | ||||
| -rw-r--r-- | fs/block_dev.c | 83 | ||||
| -rw-r--r-- | include/linux/fs.h | 6 |
3 files changed, 73 insertions, 32 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 44c9985f352a..3036883fc9f8 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -924,6 +924,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, struct file *file; struct inode *inode; struct address_space *mapping; + struct block_device *claimed_bdev = NULL; int lo_flags = 0; int error; loff_t size; @@ -942,10 +943,11 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, * here to avoid changing device under exclusive owner. */ if (!(mode & FMODE_EXCL)) { - bdgrab(bdev); - error = blkdev_get(bdev, mode | FMODE_EXCL, loop_set_fd); - if (error) + claimed_bdev = bd_start_claiming(bdev, loop_set_fd); + if (IS_ERR(claimed_bdev)) { + error = PTR_ERR(claimed_bdev); goto out_putf; + } } error = mutex_lock_killable(&loop_ctl_mutex); @@ -1015,15 +1017,15 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, mutex_unlock(&loop_ctl_mutex); if (partscan) loop_reread_partitions(lo, bdev); - if (!(mode & FMODE_EXCL)) - blkdev_put(bdev, mode | FMODE_EXCL); + if (claimed_bdev) + bd_abort_claiming(bdev, claimed_bdev, loop_set_fd); return 0; out_unlock: mutex_unlock(&loop_ctl_mutex); out_bdev: - if (!(mode & FMODE_EXCL)) - blkdev_put(bdev, mode | FMODE_EXCL); + if (claimed_bdev) + bd_abort_claiming(bdev, claimed_bdev, loop_set_fd); out_putf: fput(file); out: diff --git a/fs/block_dev.c b/fs/block_dev.c index c2a85b587922..22591bad9353 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1181,8 +1181,7 @@ static struct gendisk *bdev_get_gendisk(struct block_device *bdev, int *partno) * Pointer to the block device containing @bdev on success, ERR_PTR() * value on failure. */ -static struct block_device *bd_start_claiming(struct block_device *bdev, - void *holder) +struct block_device *bd_start_claiming(struct block_device *bdev, void *holder) { struct gendisk *disk; struct block_device *whole; @@ -1229,6 +1228,62 @@ static struct block_device *bd_start_claiming(struct block_device *bdev, return ERR_PTR(err); } } +EXPORT_SYMBOL(bd_start_claiming); + +static void bd_clear_claiming(struct block_device *whole, void *holder) +{ + lockdep_assert_held(&bdev_lock); + /* tell others that we're done */ + BUG_ON(whole->bd_claiming != holder); + whole->bd_claiming = NULL; + wake_up_bit(&whole->bd_claiming, 0); +} + +/** + * bd_finish_claiming - finish claiming of a block device + * @bdev: block device of interest + * @whole: whole block device (returned from bd_start_claiming()) + * @holder: holder that has claimed @bdev + * + * Finish exclusive open of a block device. Mark the device as exlusively + * open by the holder and wake up all waiters for exclusive open to finish. + */ +void bd_finish_claiming(struct block_device *bdev, struct block_device *whole, + void *holder) +{ + spin_lock(&bdev_lock); + BUG_ON(!bd_may_claim(bdev, whole, holder)); + /* + * Note that for a whole device bd_holders will be incremented twice, + * and bd_holder will be set to bd_may_claim before being set to holder + */ + whole->bd_holders++; + whole->bd_holder = bd_may_claim; + bdev->bd_holders++; + bdev->bd_holder = holder; + bd_clear_claiming(whole, holder); + spin_unlock(&bdev_lock); +} +EXPORT_SYMBOL(bd_finish_claiming); + +/** + * bd_abort_claiming - abort claiming of a block device + * @bdev: block device of interest + * @whole: whole block device (returned from bd_start_claiming()) + * @holder: holder that has claimed @bdev + * + * Abort claiming of a block device when the exclusive open failed. This can be + * also used when exclusive open is not actually desired and we just needed + * to block other exclusive openers for a while. + */ +void bd_abort_claiming(struct block_device *bdev, struct block_device *whole, + void *holder) +{ + spin_lock(&bdev_lock); + bd_clear_claiming(whole, holder); + spin_unlock(&bdev_lock); +} +EXPORT_SYMBOL(bd_abort_claiming); #ifdef CONFIG_SYSFS struct bd_holder_disk { @@ -1698,29 +1753,7 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) /* finish claiming */ mutex_lock(&bdev->bd_mutex); - spin_lock(&bdev_lock); - - if (!res) { - BUG_ON(!bd_may_claim(bdev, whole, holder)); - /* - * Note that for a whole device bd_holders - * will be incremented twice, and bd_holder - * will be set to bd_may_claim before being - * set to holder - */ - whole->bd_holders++; - whole->bd_holder = bd_may_claim; - bdev->bd_holders++; - bdev->bd_holder = holder; - } - - /* tell others that we're done */ - BUG_ON(whole->bd_claiming != holder); - whole->bd_claiming = NULL; - wake_up_bit(&whole->bd_claiming, 0); - - spin_unlock(&bdev_lock); - + bd_finish_claiming(bdev, whole, holder); /* * Block event polling for write claims if requested. Any * write holder makes the write_holder state stick until diff --git a/include/linux/fs.h b/include/linux/fs.h index 56b8e358af5c..997a530ff4e9 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2598,6 +2598,12 @@ extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, void *holder); extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder); +extern struct block_device *bd_start_claiming(struct block_device *bdev, + void *holder); +extern void bd_finish_claiming(struct block_device *bdev, + struct block_device *whole, void *holder); +extern void bd_abort_claiming(struct block_device *bdev, + struct block_device *whole, void *holder); extern void blkdev_put(struct block_device *bdev, fmode_t mode); extern int __blkdev_reread_part(struct block_device *bdev); extern int blkdev_reread_part(struct block_device *bdev); |