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>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 1e01f0d8312a0041949c4ecd7afbeb015b4fe182..e7d10d384f075050d3d84d8e8127e29d9f9a8121 100644 (file)
--- 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,