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authorAlex Elder <elder@inktank.com>2012-11-16 09:29:16 -0600
committerAlex Elder <elder@inktank.com>2012-12-17 08:36:59 -0600
commit42382b709bd1d143b9f0fa93e0a3a1f2f4210707 (patch)
tree2d6a8c6910ab15bffed7ab91d74005e05984f891 /drivers/block
parent8884d53dd63b1d9315b343564fcbe1ede004a99e (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>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/rbd.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 842caf4aab47..c7bf9613ad40 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -235,6 +235,7 @@ struct rbd_device {
/* sysfs related */
struct device dev;
+ unsigned long open_count;
};
static DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */
@@ -309,8 +310,11 @@ static int rbd_open(struct block_device *bdev, fmode_t mode)
if ((mode & FMODE_WRITE) && rbd_dev->mapping.read_only)
return -EROFS;
+ mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
rbd_get_dev(rbd_dev);
set_device_ro(bdev, rbd_dev->mapping.read_only);
+ rbd_dev->open_count++;
+ mutex_unlock(&ctl_mutex);
return 0;
}
@@ -319,7 +323,11 @@ 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);
+ rbd_assert(rbd_dev->open_count > 0);
+ rbd_dev->open_count--;
rbd_put_dev(rbd_dev);
+ mutex_unlock(&ctl_mutex);
return 0;
}
@@ -3745,6 +3753,11 @@ 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);