fuse: add request extension

Will need to add supplementary groups to create messages, so add the
general concept of a request extension.  A request extension is appended to
the end of the main request.  It has a header indicating the size and type
of the extension.

The create security context (fuse_secctx_*) is similar to the generic
request extension, so include that as well in a backward compatible manner.

Add the total extension length to the request header.  The offset of the
extension block within the request can be calculated by:

  inh->len - inh->total_extlen * 8

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index c673faefdcb9..ac300f14aa2d 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -249,8 +249,9 @@ struct fuse_page_desc {
 struct fuse_args {
 	uint64_t nodeid;
 	uint32_t opcode;
-	unsigned short in_numargs;
-	unsigned short out_numargs;
+	uint8_t in_numargs;
+	uint8_t out_numargs;
+	uint8_t ext_idx;
 	bool force:1;
 	bool noreply:1;
 	bool nocreds:1;
@@ -261,6 +262,7 @@ struct fuse_args {
 	bool page_zeroing:1;
 	bool page_replace:1;
 	bool may_block:1;
+	bool is_ext:1;
 	struct fuse_in_arg in_args[3];
 	struct fuse_arg out_args[2];
 	void (*end)(struct fuse_mount *fm, struct fuse_args *args, int error);