fuse: add support for mandatory locking

For mandatory locking the userspace filesystem needs to know the lock
ownership for read, write and truncate operations.

This patch adds the necessary fields to the protocol.

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, 5 insertions, 0 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 052327bd6c9d..6c83ed052026 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1108,6 +1108,11 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
                 inarg.valid |= FATTR_FH;
                 inarg.fh = ff->fh;
         }
+        if (attr->ia_valid & ATTR_SIZE) {
+                /* For mandatory locking in truncate */
+                inarg.valid |= FATTR_LOCKOWNER;
+                inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
+        }
         req->in.h.opcode = FUSE_SETATTR;
         req->in.h.nodeid = get_node_id(inode);
         req->in.numargs = 1;