From: Miklos Szeredi <mszeredi@suse.cz>
Date: Mon, 4 Feb 2013 14:57:42 +0000 (+0100)
Subject: fuse: don't WARN when nlink is zero
X-Git-Tag: v3.4.35~16
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=146207bbadeb4578334d6e26b9b690df8aeb1a3d;p=karo-tx-linux.git

fuse: don't WARN when nlink is zero

commit dfca7cebc2679f3d129f8e680a8f199a7ad16e38 upstream.

drop_nlink() warns if nlink is already zero.  This is triggerable by a buggy
userspace filesystem.  The cure, I think, is worse than the disease so disable
the warning.

Reported-by: Tero Roponen <tero.roponen@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index bc438320cac5..d48478a864b0 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -645,7 +645,14 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
 
 		spin_lock(&fc->lock);
 		fi->attr_version = ++fc->attr_version;
-		drop_nlink(inode);
+		/*
+		 * If i_nlink == 0 then unlink doesn't make sense, yet this can
+		 * happen if userspace filesystem is careless.  It would be
+		 * difficult to enforce correct nlink usage so just ignore this
+		 * condition here
+		 */
+		if (inode->i_nlink > 0)
+			drop_nlink(inode);
 		spin_unlock(&fc->lock);
 		fuse_invalidate_attr(inode);
 		fuse_invalidate_attr(dir);