From: Miklos Szeredi <mszeredi@redhat.com>
Date: Tue, 12 Nov 2019 11:49:04 +0100
Subject: fuse: verify nlink
Git-commit: c634da718db9b2fac201df2ae1b1b095344ce5eb
Patch-mainline: 5.5-rc1
References: bnc#1151927 5.3.16

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: Jiri Slaby <jslaby@suse.cz>
---
 fs/fuse/dir.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -822,7 +822,8 @@ static int fuse_link(struct dentry *entr
 
 		spin_lock(&fi->lock);
 		fi->attr_version = atomic64_inc_return(&fc->attr_version);
-		inc_nlink(inode);
+		if (likely(inode->i_nlink < UINT_MAX))
+			inc_nlink(inode);
 		spin_unlock(&fi->lock);
 		fuse_invalidate_attr(inode);
 		fuse_update_ctime(inode);