rbd: ignore unmapped snapshots that no longer exist

This prevents erroring out while adding a device when a snapshot
unrelated to the current mapping is deleted between reading the
snapshot context and reading the snapshot names. If the mapped
snapshot name is not found an error still occurs as usual.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 47c6f9cf9dba9952dd7340efe5bd27e0af102915..626a7136fb2f4d5c94c096a93c2f78c0c37c9c8e 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4078,8 +4078,13 @@ static u64 rbd_v2_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
 
                snap_id = snapc->snaps[which];
                snap_name = rbd_dev_v2_snap_name(rbd_dev, snap_id);
-               if (IS_ERR(snap_name))
-                       break;
+               if (IS_ERR(snap_name)) {
+                       /* ignore no-longer existing snapshots */
+                       if (PTR_ERR(snap_name) == -ENOENT)
+                               continue;
+                       else
+                               break;
+               }
                found = !strcmp(name, snap_name);
                kfree(snap_name);
        }