fuse: fix READDIRPLUS skipping an entry

Marios Titas running a Haskell program noticed a problem with fuse's
readdirplus: when it is interrupted by a signal, it skips one directory
entry.

The reason is that fuse erronously updates ctx->pos after a failed
dir_emit().

The issue originates from the patch adding readdirplus support.

Reported-by: Jakob Unterwurzacher <jakobunt@gmail.com>
Tested-by: Marios Titas <redneb@gmx.com> 
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 0b05b18381ee ("fuse: implement NFS-like readdirplus support")
Cc: <stable@vger.kernel.org> # v3.9

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 622081b97426..24967382a7b1 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1308,7 +1308,8 @@ static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
                         */
                         over = !dir_emit(ctx, dirent->name, dirent->namelen,
                                        dirent->ino, dirent->type);
-                        ctx->pos = dirent->off;
+                        if (!over)
+                                ctx->pos = dirent->off;
                 }
 
                 buf += reclen;