From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9CF6C433E0 for ; Mon, 29 Jun 2020 19:53:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 884D620674 for ; Mon, 29 Jun 2020 19:53:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593460420; bh=PWwSGPaAWlshTJtLfUNbhAsYEOo+eXVM/5Nwvf7UQOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ADMhIdZx/6OWCIbzIxBIa/mixIwrl6LHqkJItn+ZIQwRTHfE30dNbMFZyOe6hNkhV ADAXiN6/+Smn9+ILMcAhxZfWcFNN3KP6h8dnrhFDwy14yVx3uKcOSUkFLkbHKQomFF R9TXdX7pBUm6GoKq994ROlZWHvSIeFV4sHSyKYdQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726047AbgF2Txi (ORCPT ); Mon, 29 Jun 2020 15:53:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:47696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387679AbgF2Tk0 (ORCPT ); Mon, 29 Jun 2020 15:40:26 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6140824842; Mon, 29 Jun 2020 15:25:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593444354; bh=PWwSGPaAWlshTJtLfUNbhAsYEOo+eXVM/5Nwvf7UQOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vaWbaQ5TZSnTJh9OvBfNnXNtvczOJ1hThP9e2wrqHNsQrScGW6WB/rUrTQaagQqef VnTG7g/qD0L05S011CIkchocTY4A5s5Q0KypoSQZJM8uA/MGwTFAsRvHWy53nbIuce yaf1lBxT6VPbGFwA23fcJDKN1IcCTmRguhAjN46w= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sasha Levin , Nikolay Borisov , Anand Jain , Filipe Manana , David Sterba Subject: [PATCH 5.4 029/178] btrfs: fix a block group ref counter leak after failure to remove block group Date: Mon, 29 Jun 2020 11:22:54 -0400 Message-Id: <20200629152523.2494198-30-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629152523.2494198-1-sashal@kernel.org> References: <20200629152523.2494198-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.4.50-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.4.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.4.50-rc1 X-KernelTest-Deadline: 2020-07-01T15:25+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 9fecd13202f520f3f25d5b1c313adb740fe19773 ] When removing a block group, if we fail to delete the block group's item from the extent tree, we jump to the 'out' label and end up decrementing the block group's reference count once only (by 1), resulting in a counter leak because the block group at that point was already removed from the block group cache rbtree - so we have to decrement the reference count twice, once for the rbtree and once for our lookup at the start of the function. There is a second bug where if removing the free space tree entries (the call to remove_block_group_free_space()) fails we end up jumping to the 'out_put_group' label but end up decrementing the reference count only once, when we should have done it twice, since we have already removed the block group from the block group cache rbtree. This happens because the reference count decrement for the rbtree reference happens after attempting to remove the free space tree entries, which is far away from the place where we remove the block group from the rbtree. To make things less error prone, decrement the reference count for the rbtree immediately after removing the block group from it. This also eleminates the need for two different exit labels on error, renaming 'out_put_label' to just 'out' and removing the old 'out'. Fixes: f6033c5e333238 ("btrfs: fix block group leak when removing fails") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Nikolay Borisov Reviewed-by: Anand Jain Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/block-group.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index c2dd94e1b274c..42d69e77f89d9 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -910,7 +910,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; - goto out_put_group; + goto out; } /* @@ -948,7 +948,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, ret = btrfs_orphan_add(trans, BTRFS_I(inode)); if (ret) { btrfs_add_delayed_iput(inode); - goto out_put_group; + goto out; } clear_nlink(inode); /* One for the block groups ref */ @@ -971,13 +971,13 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); if (ret < 0) - goto out_put_group; + goto out; if (ret > 0) btrfs_release_path(path); if (ret == 0) { ret = btrfs_del_item(trans, tree_root, path); if (ret) - goto out_put_group; + goto out; btrfs_release_path(path); } @@ -986,6 +986,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, &fs_info->block_group_cache_tree); RB_CLEAR_NODE(&block_group->cache_node); + /* Once for the block groups rbtree */ + btrfs_put_block_group(block_group); + if (fs_info->first_logical_byte == block_group->key.objectid) fs_info->first_logical_byte = (u64)-1; spin_unlock(&fs_info->block_group_cache_lock); @@ -1094,10 +1097,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, ret = remove_block_group_free_space(trans, block_group); if (ret) - goto out_put_group; - - /* Once for the block groups rbtree */ - btrfs_put_block_group(block_group); + goto out; ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret > 0) @@ -1120,10 +1120,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, free_extent_map(em); } -out_put_group: +out: /* Once for the lookup reference */ btrfs_put_block_group(block_group); -out: if (remove_rsv) btrfs_delayed_refs_rsv_release(fs_info, 1); btrfs_free_path(path); -- 2.25.1