rbd: ignore unmapped snapshots that no longer exist

commit efadc98aab674153709cc357ba565f04e3164fcd upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 58a4e03b7311..e917d4f7b76e 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4055,8 +4055,13 @@ 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);
         }