bcache-tools: check incompatible feature set

When bcache-tools is not updated with kernel driver (or on the versus),
we need to make sure the feature set conflict can be detected to avoid
unexpected data operation.

This patch checks whether there is unsupported {compatc, ro_compat,
incompat} features detected in detail_dev(). If there is, prints out
error message and return error to its caller.

Signed-off-by: Coly Li <colyli@suse.de>

1 files changed, 27 insertions, 0 deletions

diff --git a/lib.c b/lib.c
index 29172f5f..a529ad3e 100644
--- a/lib.c
+++ b/lib.c
@@ -442,6 +442,33 @@ int detail_dev(char *devname, struct bdev *bd, struct cdev *cd, int *type)
 		goto Fail;
 	}
 
+	/* Check for incompat feature set */
+	if (sb.version >= BCACHE_SB_VERSION_BDEV_WITH_FEATURES ||
+	    sb.version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
+		uint64_t features;
+
+		features = sb.feature_compat & ~BCH_FEATURE_COMPAT_SUPP;
+		if (features) {
+			fprintf(stderr,
+				"Unsupported compatible feature found\n");
+			goto Fail;
+		}
+
+		features = sb.feature_ro_compat & ~BCH_FEATURE_RO_COMPAT_SUPP;
+		if (features) {
+			fprintf(stderr,
+				"Unsupported read-only compatible feature found\n");
+			goto Fail;
+		}
+
+		features = sb.feature_incompat & ~BCH_FEATURE_INCOMPAT_SUPP;
+		if (features) {
+			fprintf(stderr,
+				"Unsupported incompatible feature found\n");
+			goto Fail;
+		}
+	}
+
 	*type = sb.version;
 	if (sb.version == BCACHE_SB_VERSION_BDEV ||
 	    sb.version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET ||