orangefs: add features op
This is a new userspace operation, which will be done if the client-core
version is greater than or equal to 2.9.6. This will provide a way to
implement optional features and to determine which features are
supported by the client-core. If the client-core version is older than
2.9.6, no optional features are supported and the op will not be done.
The intent is to allow protocol extensions without relying on the
client-core's current behavior of ignoring what it doesn't understand.
Signed-off-by: Martin Brandenburg <martin@omnibond.com>
diff --git a/fs/orangefs/orangefs-dev-proto.h b/fs/orangefs/orangefs-dev-proto.h
index 7190289..a3d84ff 100644
--- a/fs/orangefs/orangefs-dev-proto.h
+++ b/fs/orangefs/orangefs-dev-proto.h
@@ -41,6 +41,10 @@
#define ORANGEFS_VFS_OP_FSYNC 0xFF00EE01
#define ORANGEFS_VFS_OP_FSKEY 0xFF00EE02
#define ORANGEFS_VFS_OP_READDIRPLUS 0xFF00EE03
+#define ORANGEFS_VFS_OP_FEATURES 0xFF00EE05 /* 2.9.6 */
+
+/* features is a 64-bit unsigned bitmask */
+#define ORANGEFS_FEATURE_READAHEAD 1
/*
* Misc constants. Please retain them as multiples of 8!