From d889140c4a1c5edb6a7bd90392b9d878bfaccfb6 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Tue, 9 Oct 2012 13:50:17 -0700 Subject: [PATCH] rbd: implement feature checks Version 2 images have two sets of feature bit fields. The first indicates features possibly used by the image. The second indicates features that the client *must* support in order to use the image. When an image (or snapshot) is first examined, we need to make sure that the local implementation supports the image's required features. If not, fail the probe for the image. Signed-off-by: Alex Elder Reviewed-by: Josh Durgin --- drivers/block/rbd.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index f11b839166ef..0f260a6e97c4 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -70,6 +70,14 @@ #define RBD_IMAGE_ID_LEN_MAX 64 #define RBD_OBJ_PREFIX_LEN_MAX 64 +/* Feature bits */ + +#define RBD_FEATURE_LAYERING 1 + +/* Features supported by this (client software) implementation. */ + +#define RBD_FEATURES_ALL (0) + /* * An RBD device name will be "rbd#", where the "rbd" comes from * RBD_DRV_NAME above, and # is a unique integer identifier. @@ -2226,6 +2234,7 @@ static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id, __le64 features; __le64 incompat; } features_buf = { 0 }; + u64 incompat; int ret; ret = rbd_req_sync_exec(rbd_dev, rbd_dev->header_name, @@ -2236,6 +2245,11 @@ static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id, dout("%s: rbd_req_sync_exec returned %d\n", __func__, ret); if (ret < 0) return ret; + + incompat = le64_to_cpu(features_buf.incompat); + if (incompat & ~RBD_FEATURES_ALL) + return -ENOTSUPP; + *snap_features = le64_to_cpu(features_buf.features); dout(" snap_id 0x%016llx features = 0x%016llx incompat = 0x%016llx\n", @@ -2977,7 +2991,7 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev) if (ret < 0) goto out_err; - /* Get the features for the image */ + /* Get the and check features for the image */ ret = rbd_dev_v2_features(rbd_dev); if (ret < 0)