fuse: fix flock breakage

Commit 37fb3a30b4 ("fuse: fix flock") added in 3.1-rc4 caused flock() to
fail with ENOSYS with the kernel ABI version 7.16 or earlier.

Fix by falling back to testing FUSE_POSIX_LOCKS for ABI versions 7.16
and earlier.

Reported-by: Martin Ziegler <ziegler@email.mathematik.uni-freiburg.de>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Martin Ziegler <ziegler@email.mathematik.uni-freiburg.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 12b502929da9..add96f6ffda5 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -812,6 +812,9 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
                         if (arg->minor >= 17) {
                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
                                         fc->no_flock = 1;
+                        } else {
+                                if (!(arg->flags & FUSE_POSIX_LOCKS))
+                                        fc->no_flock = 1;
                         }
                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
                                 fc->atomic_o_trunc = 1;