fuse: verify nlink

commit c634da718db9b2fac201df2ae1b1b095344ce5eb upstream.

When adding a new hard link, make sure that i_nlink doesn't overflow.

Fixes: ac45d61357e8 ("fuse: fix nlink after unlink")
Cc: <stable@vger.kernel.org> # v3.4
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 1d9fec9c714b23fca1f65b0398c4a54f21def91d..15b755971fae3b34a828411274caf7425fd7531d 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -830,7 +830,8 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
 
                spin_lock(&fc->lock);
                fi->attr_version = ++fc->attr_version;
-               inc_nlink(inode);
+               if (likely(inode->i_nlink < UINT_MAX))
+                       inc_nlink(inode);
                spin_unlock(&fc->lock);
                fuse_invalidate_attr(inode);
                fuse_update_ctime(inode);