diff options
Diffstat (limited to 'fs/block_dev.c')
| -rw-r--r-- | fs/block_dev.c | 86 |
1 files changed, 61 insertions, 25 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 4707dfff991b..677cb364d33f 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1139,8 +1139,7 @@ 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; @@ -1187,6 +1186,62 @@ 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 { @@ -1656,29 +1711,10 @@ 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); - + if (!res) + bd_finish_claiming(bdev, whole, holder); + else + bd_abort_claiming(bdev, whole, holder); /* * Block event polling for write claims if requested. Any * write holder makes the write_holder state stick until |