Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752747Ab0HWBSw (ORCPT ); Sun, 22 Aug 2010 21:18:52 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:55219 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751688Ab0HWBSu (ORCPT ); Sun, 22 Aug 2010 21:18:50 -0400 Message-ID: <4C71CDA0.5010107@cn.fujitsu.com> Date: Mon, 23 Aug 2010 09:23:44 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Chris Mason CC: Josef Bacik , linux-btrfs@vger.kernel.org, LKML Subject: [PATCH 5/6] btrfs: add a helper try_merge_free_space() References: <4C71CD4B.10606@cn.fujitsu.com> In-Reply-To: <4C71CD4B.10606@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3687 Lines: 130 When adding a new extent, we'll firstly see if we can merge this extent to the left or/and right extent. Extract this as a helper try_merge_free_space(). As a side effect, we fix a small bug that if the new extent has non-bitmap left entry but is unmergeble, we'll directly link the extent without trying to drop it into bitmap. This also prepares for the next patch. Signed-off-by: Li Zefan --- fs/btrfs/free-space-cache.c | 75 ++++++++++++++++++++++++------------------ 1 files changed, 43 insertions(+), 32 deletions(-) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 20f3141..faeec8f 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -610,22 +610,14 @@ out: return ret; } -int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) +bool try_merge_free_space(struct btrfs_block_group_cache *block_group, + struct btrfs_free_space *info) { - struct btrfs_free_space *right_info = NULL; - struct btrfs_free_space *left_info = NULL; - struct btrfs_free_space *info = NULL; - int ret = 0; - - info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); - if (!info) - return -ENOMEM; - - info->offset = offset; - info->bytes = bytes; - - spin_lock(&block_group->tree_lock); + struct btrfs_free_space *left_info; + struct btrfs_free_space *right_info; + bool merged = false; + u64 offset = info->offset; + u64 bytes = info->bytes; /* * first we want to see if there is free space adjacent to the range we @@ -639,27 +631,11 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, else left_info = tree_search_offset(block_group, offset - 1, 0, 0); - /* - * If there was no extent directly to the left or right of this new - * extent then we know we're going to have to allocate a new extent, so - * before we do that see if we need to drop this into a bitmap - */ - if ((!left_info || left_info->bitmap) && - (!right_info || right_info->bitmap)) { - ret = insert_into_bitmap(block_group, info); - - if (ret < 0) { - goto out; - } else if (ret) { - ret = 0; - goto out; - } - } - if (right_info && !right_info->bitmap) { unlink_free_space(block_group, right_info); info->bytes += right_info->bytes; kfree(right_info); + merged = true; } if (left_info && !left_info->bitmap && @@ -668,8 +644,43 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, info->offset = left_info->offset; info->bytes += left_info->bytes; kfree(left_info); + merged = true; } + return merged; +} + +int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, + u64 offset, u64 bytes) +{ + struct btrfs_free_space *info; + int ret = 0; + + info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); + if (!info) + return -ENOMEM; + + info->offset = offset; + info->bytes = bytes; + + spin_lock(&block_group->tree_lock); + + if (try_merge_free_space(block_group, info)) + goto link; + + /* + * There was no extent directly to the left or right of this new + * extent then we know we're going to have to allocate a new extent, so + * before we do that see if we need to drop this into a bitmap + */ + ret = insert_into_bitmap(block_group, info); + if (ret < 0) { + goto out; + } else if (ret) { + ret = 0; + goto out; + } +link: ret = link_free_space(block_group, info); if (ret) kfree(info); -- 1.7.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/