rbd: drop dev reference on error in rbd_open()

If a read-only rbd device is opened for writing in rbd_open(), it
returns without dropping the just-acquired device reference.

Fix this by moving the read-only check before getting the reference.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 9917943a3572ef577ac7a511ef375d11dae08350..54a55f03115df1df8dddb45e354eb8246336e56b 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -246,13 +246,12 @@ static int rbd_open(struct block_device *bdev, fmode_t mode)
 {
        struct rbd_device *rbd_dev = bdev->bd_disk->private_data;
 
-       rbd_get_dev(rbd_dev);
-
-       set_device_ro(bdev, rbd_dev->read_only);
-
        if ((mode & FMODE_WRITE) && rbd_dev->read_only)
                return -EROFS;
 
+       rbd_get_dev(rbd_dev);
+       set_device_ro(bdev, rbd_dev->read_only);
+
        return 0;
 }