From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:2871 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030942Ab3HIUh1 (ORCPT ); Fri, 9 Aug 2013 16:37:27 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r79KbRu0004131 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 9 Aug 2013 16:37:27 -0400 Received: from lenny.home.zabbo.net (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r79KbNvk001231 for ; Fri, 9 Aug 2013 16:37:27 -0400 From: Zach Brown To: linux-btrfs@vger.kernel.org Subject: [PATCH 2/2] btrfs: don't double brelse on device rm Date: Fri, 9 Aug 2013 13:37:14 -0700 Message-Id: <1376080634-1714-2-git-send-email-zab@redhat.com> In-Reply-To: <1376080634-1714-1-git-send-email-zab@redhat.com> References: <1376080634-1714-1-git-send-email-zab@redhat.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: Device removal currently causes bdev removal to try to double free a bh in the bdev: [ 55.714833] WARNING: at fs/buffer.c:1160 __brelse+0x36/0x40() [ 55.714833] VFS: brelse: Trying to free free buffer Commit 7e3d9ebb1 added a double release of the bh for a device being removed when all the supers don't fit in the device. In that case it releases the bh assuming that it's going to read a new one, finds that it won't read, and goes to a label that releases the bh again. All it needed to do was only brelse() right before overwriting the current bh with __bread(). Signed-off-by: Zach Brown --- fs/btrfs/volumes.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 090f57c..adb0bca 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1656,11 +1656,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path) * the below would take of the rest */ for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) { - brelse(bh); bytenr = btrfs_sb_offset(i); if (bytenr + BTRFS_SUPER_INFO_SIZE >= i_size_read(bdev->bd_inode)) break; + + brelse(bh); bh = __bread(bdev, bytenr / 4096, BTRFS_SUPER_INFO_SIZE); if (!bh) -- 1.7.11.7