From patchwork Tue Jul 16 22:53:59 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 259541 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3A1DF2C0102 for ; Wed, 17 Jul 2013 09:02:50 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UzEGZ-0001Wf-GX; Tue, 16 Jul 2013 23:02:43 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UzE89-0000Ns-Hl for kernel-team@lists.ubuntu.com; Tue, 16 Jul 2013 22:54:01 +0000 Received: from c-67-160-231-162.hsd1.ca.comcast.net ([67.160.231.162] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UzE89-00044R-BT; Tue, 16 Jul 2013 22:54:01 +0000 Received: from kamal by fourier with local (Exim 4.80) (envelope-from ) id 1UzE87-0007At-8Z; Tue, 16 Jul 2013 15:53:59 -0700 From: Kamal Mostafa To: Josef Bacik Subject: [ 3.8.y.z extended stable ] Patch "Btrfs: only do the tree_mod_log_free_eb if this is our last ref" has been added to staging queue Date: Tue, 16 Jul 2013 15:53:59 -0700 Message-Id: <1374015239-27549-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 X-Extended-Stable: 3.8 Cc: Kamal Mostafa , kernel-team@lists.ubuntu.com, Jan Schmidt X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled Btrfs: only do the tree_mod_log_free_eb if this is our last ref to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.5. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 5f9a03cddbea2363e3e591605501060aacdc9352 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Mon, 1 Jul 2013 16:10:16 -0400 Subject: Btrfs: only do the tree_mod_log_free_eb if this is our last ref commit 7fb7d76f96bfcbea25007d190ba828b18e13d29d upstream. There is another bug in the tree mod log stuff in that we're calling tree_mod_log_free_eb every single time a block is cow'ed. The problem with this is that if this block is shared by multiple snapshots we will call this multiple times per block, so if we go to rewind the mod log for this block we'll BUG_ON() in __tree_mod_log_rewind because we try to rewind a free twice. We only want to call tree_mod_log_free_eb if we are actually freeing the block. With this patch I no longer hit the panic in __tree_mod_log_rewind. Thanks, Reviewed-by: Jan Schmidt Signed-off-by: Josef Bacik Signed-off-by: Kamal Mostafa --- fs/btrfs/ctree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 1.8.1.2 diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 7a11fb7..d24e546 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1049,7 +1049,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, btrfs_set_node_ptr_generation(parent, parent_slot, trans->transid); btrfs_mark_buffer_dirty(parent); - tree_mod_log_free_eb(root->fs_info, buf); + if (last_ref) + tree_mod_log_free_eb(root->fs_info, buf); btrfs_free_tree_block(trans, root, buf, parent_start, last_ref); }