fuse: support BSD locking semantics

It is trivial to add support for flock(2) semantics to the existing protocol,
by setting the lock owner field to the file pointer, and passing a new
FUSE_LK_FLOCK flag with the locking request.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/fuse.h b/include/linux/fuse.h
index 436047093bc4..015a8b15a388 100644
--- a/include/linux/fuse.h
+++ b/include/linux/fuse.h
@@ -13,6 +13,7 @@
  *
  * 7.9:
  *  - new fuse_getattr_in input argument of GETATTR
+ *  - add lk_flags in fuse_lk_in
  */
 
 #include <asm/types.h>
@@ -113,6 +114,11 @@ struct fuse_file_lock {
  */
 #define FUSE_GETATTR_FH         (1 << 0)
 
+/**
+ * Lock flags
+ */
+#define FUSE_LK_FLOCK           (1 << 0)
+
 enum fuse_opcode {
         FUSE_LOOKUP        = 1,
         FUSE_FORGET        = 2,  /* no reply */
@@ -295,6 +301,8 @@ struct fuse_lk_in {
         __u64   fh;
         __u64   owner;
         struct fuse_file_lock lk;
+        __u32   lk_flags;
+        __u32   padding;
 };
 
 struct fuse_lk_out {