diff options
| author | Alex Elder <elder@inktank.com> | 2012-11-16 09:29:16 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-17 08:51:21 -0800 |
| commit | 3317122449a2ce5c0bba77e1f05b1df2ff716447 (patch) | |
| tree | 56de6b861daee00e1f6399e46c94f0fde7ddfdc1 | |
| parent | 1e411c66732294f5fb983323dafa7559796481f5 (diff) | |
rbd: do not allow remove of mounted-on image
There is no check in rbd_remove() to see if anybody holds open the
image being removed. That's not cool.
Add a simple open count that goes up and down with opens and closes
(releases) of the device, and don't allow an rbd image to be removed
if the count is non-zero.
Protect the updates of the open count value with ctl_mutex to ensure
the underlying rbd device doesn't get removed while concurrently
being opened.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(based on commit 42382b709bd1d143b9f0fa93e0a3a1f2f4210707)
| -rw-r--r-- | drivers/block/rbd.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index d9ebe6844da6..cba3d0278b86 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -189,6 +189,7 @@ struct rbd_device { /* sysfs related */ struct device dev; + unsigned long open_count; }; static DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */ @@ -249,8 +250,11 @@ static int rbd_open(struct block_device *bdev, fmode_t mode) if ((mode & FMODE_WRITE) && rbd_dev->read_only) return -EROFS; + mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); rbd_get_dev(rbd_dev); set_device_ro(bdev, rbd_dev->read_only); + rbd_dev->open_count++; + mutex_unlock(&ctl_mutex); return 0; } @@ -259,7 +263,11 @@ static int rbd_release(struct gendisk *disk, fmode_t mode) { struct rbd_device *rbd_dev = disk->private_data; + mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); + BUG_ON(!rbd_dev->open_count); + rbd_dev->open_count--; rbd_put_dev(rbd_dev); + mutex_unlock(&ctl_mutex); return 0; } @@ -2448,6 +2456,11 @@ static ssize_t rbd_remove(struct bus_type *bus, goto done; } + if (rbd_dev->open_count) { + ret = -EBUSY; + goto done; + } + __rbd_remove_all_snaps(rbd_dev); rbd_bus_del_dev(rbd_dev); |