Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752966Ab0HWNPN (ORCPT ); Mon, 23 Aug 2010 09:15:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56492 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751993Ab0HWNPM (ORCPT ); Mon, 23 Aug 2010 09:15:12 -0400 Date: Mon, 23 Aug 2010 09:15:05 -0400 From: Josef Bacik To: Li Zefan Cc: Chris Mason , Josef Bacik , linux-btrfs@vger.kernel.org, LKML Subject: Re: [PATCH 6/6] btrfs: check mergeable free space when removing a cluster Message-ID: <20100823131504.GE2404@localhost.localdomain> References: <4C71CD4B.10606@cn.fujitsu.com> <4C71CDB7.6000602@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C71CDB7.6000602@cn.fujitsu.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3662 Lines: 100 On Mon, Aug 23, 2010 at 09:24:07AM +0800, Li Zefan wrote: > After returing extents from a cluster to the block group, some > extents in the block group may be mergeable. > > Signed-off-by: Li Zefan > --- > fs/btrfs/free-space-cache.c | 26 ++++++++++++++++++++------ > 1 files changed, 20 insertions(+), 6 deletions(-) > > diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c > index faeec8f..c11f4f7 100644 > --- a/fs/btrfs/free-space-cache.c > +++ b/fs/btrfs/free-space-cache.c > @@ -234,11 +234,18 @@ tree_search_offset(struct btrfs_block_group_cache *block_group, > return entry; > } > > -static void unlink_free_space(struct btrfs_block_group_cache *block_group, > - struct btrfs_free_space *info) > +static inline void > +__unlink_free_space(struct btrfs_block_group_cache *block_group, > + struct btrfs_free_space *info) > { > rb_erase(&info->offset_index, &block_group->free_space_offset); > block_group->free_extents--; > +} > + > +static void unlink_free_space(struct btrfs_block_group_cache *block_group, > + struct btrfs_free_space *info) > +{ > + __unlink_free_space(block_group, info); > block_group->free_space -= info->bytes; > } > > @@ -611,7 +618,7 @@ out: > } > > bool try_merge_free_space(struct btrfs_block_group_cache *block_group, > - struct btrfs_free_space *info) > + struct btrfs_free_space *info, bool update_stat) > { > struct btrfs_free_space *left_info; > struct btrfs_free_space *right_info; > @@ -632,7 +639,10 @@ bool try_merge_free_space(struct btrfs_block_group_cache *block_group, > left_info = tree_search_offset(block_group, offset - 1, 0, 0); > > if (right_info && !right_info->bitmap) { > - unlink_free_space(block_group, right_info); > + if (update_stat) > + unlink_free_space(block_group, right_info); > + else > + __unlink_free_space(block_group, right_info); > info->bytes += right_info->bytes; > kfree(right_info); > merged = true; > @@ -640,7 +650,10 @@ bool try_merge_free_space(struct btrfs_block_group_cache *block_group, > > if (left_info && !left_info->bitmap && > left_info->offset + left_info->bytes == offset) { > - unlink_free_space(block_group, left_info); > + if (update_stat) > + unlink_free_space(block_group, left_info); > + else > + __unlink_free_space(block_group, left_info); > info->offset = left_info->offset; > info->bytes += left_info->bytes; > kfree(left_info); > @@ -665,7 +678,7 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, > > spin_lock(&block_group->tree_lock); > > - if (try_merge_free_space(block_group, info)) > + if (try_merge_free_space(block_group, info, true)) > goto link; > > /* > @@ -883,6 +896,7 @@ __btrfs_return_cluster_to_free_space( > node = rb_next(&entry->offset_index); > rb_erase(&entry->offset_index, &cluster->root); > BUG_ON(entry->bitmap); > + try_merge_free_space(block_group, entry, false); > tree_insert_offset(&block_group->free_space_offset, > entry->offset, &entry->offset_index, 0); It's early in the morning here, so forgive me if I'm missing something obvious, but if try_merge_free_space() succeeds here, then won't tree_insert_offset() then add an entry that overlaps the same spot? Should we do something like merged = try_merge_free_space(); if (!merged) tree_insert_offset(); ? Thanks, Josef -- 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/