From: Jeff Mahoney <jeffm@suse.com>
Date: Mon, 23 Apr 2007 21:41:17 +0000 (-0700)
Subject: reiserfs: fix xattr root locking/refcount bug
X-Git-Tag: v2.6.21~14
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9b7f375505f5611efb562065b57814b28a81abc3;p=pandora-kernel.git

reiserfs: fix xattr root locking/refcount bug

The listxattr() and getxattr() operations are only protected by a read
lock.  As a result, if either of these operations run in parallel, a race
condition exists where the xattr_root will end up being cached twice, which
results in the leaking of a reference and a BUG() on umount.

This patch refactors get_xa_root(), __get_xa_root(), and create_xa_root(),
into one get_xa_root() function that takes the appropriate locking around
the entire critical section.

Reported, diagnosed and tested by Andrea Righi <a.righi@cineca.it>

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Andrea Righi <a.righi@cineca.it>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Cc: Edward Shishkin <edward@namesys.com>
Cc: Alex Zarochentsev <zam@namesys.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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