fuse: fix retrieve length

commit c9e67d483776d8d2a5f3f70491161b205930ffe1 upstream.

In some cases fuse_retrieve() would return a short byte count if offset was
non-zero.  The data returned was correct, though.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ceb3b29..1f81f70 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1580,6 +1580,7 @@
 		req->pages[req->num_pages] = page;
 		req->num_pages++;
 
+		offset = 0;
 		num -= this_num;
 		total_len += this_num;
 		index++;