From: Eric Sandeen <sandeen@redhat.com>
Subject: [PATCH RHEL5] return ENOENT from ext3_link when racing with unlink
Date: Wed, 24 Jan 2007 10:11:02 -0600
Bugzilla: 219650
Message-Id: <45B78516.80606@redhat.com>
Changelog: [ext3] return ENOENT from ext3_link when racing with unlink


RHEL5 version.

For Bugzilla Bug 219650: 
[RHEL5 BETA2] EXT3 s_orphan list not updated for freed inode when inode->i_nlink

This is in the -mm tree now.

Return -ENOENT from ext[34]_link if we've raced with unlink and i_nlink is 0.
Doing otherwise has the potential to corrupt the orphan inode list,
because we'd wind up with an inode with a non-zero link count on the list,
and it will never get properly cleaned up & removed from the orphan list
before it is freed.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

Index: linux-2.6.18-1.2910.el5/fs/ext3/namei.c
===================================================================
--- linux-2.6.18-1.2910.el5.orig/fs/ext3/namei.c
+++ linux-2.6.18-1.2910.el5/fs/ext3/namei.c
@@ -2190,6 +2190,12 @@ static int ext3_link (struct dentry * ol
 
 	if (inode->i_nlink >= EXT3_LINK_MAX)
 		return -EMLINK;
+	/*
+	 * Return -ENOENT if we've raced with unlink and i_nlink is 0.  Doing
+	 * otherwise has the potential to corrupt the orphan inode list.
+	 */
+	if (inode->i_nlink == 0)
+		return -ENOENT;
 
 retry:
 	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS(dir->i_sb) +