fuse: handle killpriv in userspace fs

Only userspace filesystem can do the killing of suid/sgid without races.
So introduce an INIT flag and negotiate support for this.

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

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1e535f31fed0..b965934939cb 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -910,6 +910,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
                                 fc->writeback_cache = 1;
                         if (arg->flags & FUSE_PARALLEL_DIROPS)
                                 fc->parallel_dirops = 1;
+                        if (arg->flags & FUSE_HANDLE_KILLPRIV)
+                                fc->handle_killpriv = 1;
                         if (arg->time_gran && arg->time_gran <= 1000000000)
                                 fc->sb->s_time_gran = arg->time_gran;
                 } else {
@@ -941,7 +943,7 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
-                FUSE_PARALLEL_DIROPS;
+                FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV;
         req->in.h.opcode = FUSE_INIT;
         req->in.numargs = 1;
         req->in.args[0].size = sizeof(*arg);