rbd: report unsupported features to syslog

... instead of just returning an error.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 25d22da..0ede6d7 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4183,7 +4183,7 @@ static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
                __le64 features;
                __le64 incompat;
        } __attribute__ ((packed)) features_buf = { 0 };
-       u64 incompat;
+       u64 unsup;
        int ret;
 
        ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_name,
@@ -4196,9 +4196,12 @@ static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
        if (ret < sizeof (features_buf))
                return -ERANGE;
 
-       incompat = le64_to_cpu(features_buf.incompat);
-       if (incompat & ~RBD_FEATURES_SUPPORTED)
+       unsup = le64_to_cpu(features_buf.incompat) & ~RBD_FEATURES_SUPPORTED;
+       if (unsup) {
+               rbd_warn(rbd_dev, "image uses unsupported features: 0x%llx",
+                        unsup);
                return -ENXIO;
+       }
 
        *snap_features = le64_to_cpu(features_buf.features);