rbd: only update values on snap_info success

Change rbd_dev_v2_snap_info() so it only ever sets values of the
size and features parameters if looking up the snapshot name was
successful.

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

1 files changed, 19 insertions, 5 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 1e01f0d8312a..e7d10d384f07 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3908,6 +3908,7 @@ static char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev, u32 which)
         if (!reply_buf)
                 return ERR_PTR(-ENOMEM);
 
+        rbd_assert(which < rbd_dev->header.snapc->num_snaps);
         snap_id = cpu_to_le64(rbd_dev->header.snapc->snaps[which]);
         ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_name,
                                 "rbd", "get_snapshot_name",
@@ -3940,17 +3941,30 @@ static char *rbd_dev_v2_snap_info(struct rbd_device *rbd_dev, u32 which,
                 u64 *snap_size, u64 *snap_features)
 {
         u64 snap_id;
+        u64 size;
+        u64 features;
+        char *snap_name;
         int ret;
 
+        rbd_assert(which < rbd_dev->header.snapc->num_snaps);
         snap_id = rbd_dev->header.snapc->snaps[which];
-        ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, NULL, snap_size);
+        ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, NULL, &size);
         if (ret)
-                return ERR_PTR(ret);
-        ret = _rbd_dev_v2_snap_features(rbd_dev, snap_id, snap_features);
+                goto out_err;
+
+        ret = _rbd_dev_v2_snap_features(rbd_dev, snap_id, &features);
         if (ret)
-                return ERR_PTR(ret);
+                goto out_err;
+
+        snap_name = rbd_dev_v2_snap_name(rbd_dev, which);
+        if (!IS_ERR(snap_name)) {
+                *snap_size = size;
+                *snap_features = features;
+        }
 
-        return rbd_dev_v2_snap_name(rbd_dev, which);
+        return snap_name;
+out_err:
+        return ERR_PTR(ret);
 }
 
 static char *rbd_dev_snap_info(struct rbd_device *rbd_dev, u32 which,