From patchwork Thu Jul 14 03:16:18 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Li Zefan X-Patchwork-Id: 974022 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p6E3GgJJ010079 for ; Thu, 14 Jul 2011 03:16:42 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753413Ab1GNDQj (ORCPT ); Wed, 13 Jul 2011 23:16:39 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:51456 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753295Ab1GNDQj (ORCPT ); Wed, 13 Jul 2011 23:16:39 -0400 Received: from tang.cn.fujitsu.com (tang.cn.fujitsu.com [10.167.250.3]) by song.cn.fujitsu.com (Postfix) with ESMTP id C7098170117; Thu, 14 Jul 2011 11:16:36 +0800 (CST) Received: from mailserver.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id p6E3GZUv030841; Thu, 14 Jul 2011 11:16:35 +0800 Received: from [10.167.225.230] ([10.167.225.230]) by mailserver.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.1FP4) with ESMTP id 2011071411155116-828567 ; Thu, 14 Jul 2011 11:15:51 +0800 Message-ID: <4E1E5F82.9040506@cn.fujitsu.com> Date: Thu, 14 Jul 2011 11:16:18 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: Chris Mason CC: "linux-btrfs@vger.kernel.org" Subject: [PATCH 02/16] Btrfs: fix space leak when skipping small extents during trimming References: <4E1E5F59.5030208@cn.fujitsu.com> In-Reply-To: <4E1E5F59.5030208@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-07-14 11:15:51, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-07-14 11:15:52, Serialize complete at 2011-07-14 11:15:52 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Thu, 14 Jul 2011 03:16:42 +0000 (UTC) We're taking a free space extent out of the free space cache, trimming it and then putting it back into the cache. However for an extent that is smaller than the specified minimum length, it's taken out but won't be put back, which causes space leak. Signed-off-by: Li Zefan --- fs/btrfs/free-space-cache.c | 34 +++++++++++++++++----------------- 1 files changed, 17 insertions(+), 17 deletions(-) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index bf0d615..901585d 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -2463,6 +2463,7 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group, u64 bytes = 0; u64 actually_trimmed; int ret = 0; + int update_ret; *trimmed = 0; @@ -2486,6 +2487,7 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group, } if (entry->bitmap) { + bytes = 0; ret = search_bitmap(ctl, entry, &start, &bytes); if (!ret) { if (start >= end) { @@ -2493,6 +2495,8 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group, break; } bytes = min(bytes, end - start); + if (bytes < minlen) + goto next; bitmap_clear_bits(ctl, entry, start, bytes); if (entry->bytes == 0) free_bitmap(ctl, entry); @@ -2506,33 +2510,29 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group, } else { start = entry->offset; bytes = min(entry->bytes, end - start); + if (bytes < minlen) + goto next; unlink_free_space(ctl, entry); kmem_cache_free(btrfs_free_space_cachep, entry); } spin_unlock(&ctl->tree_lock); - if (bytes >= minlen) { - int update_ret; - update_ret = btrfs_update_reserved_bytes(block_group, - bytes, 1, 1); + update_ret = btrfs_update_reserved_bytes(block_group, + bytes, 1, 1); - ret = btrfs_error_discard_extent(fs_info->extent_root, - start, - bytes, - &actually_trimmed); + ret = btrfs_error_discard_extent(fs_info->extent_root, start, + bytes, &actually_trimmed); - btrfs_add_free_space(block_group, start, bytes); - if (!update_ret) - btrfs_update_reserved_bytes(block_group, - bytes, 0, 1); + btrfs_add_free_space(block_group, start, bytes); + if (!update_ret) + btrfs_update_reserved_bytes(block_group, bytes, 0, 1); - if (ret) - break; - *trimmed += actually_trimmed; - } + if (ret) + break; + *trimmed += actually_trimmed; +next: start += bytes; - bytes = 0; if (fatal_signal_pending(current)) { ret = -ERESTARTSYS;