btrfs: check link counter overflow in link(2)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4822b3132784..04babaf31a33 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4837,6 +4837,9 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
         if (root->objectid != BTRFS_I(inode)->root->objectid)
                 return -EXDEV;
 
+        if (inode->i_nlink == ~0U)
+                return -EMLINK;
+
         btrfs_inc_nlink(inode);
         inode->i_ctime = CURRENT_TIME;