From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 23 Jun 2008 19:11:39 -0700 (PDT) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with SMTP id m5O2BWHY009095 for ; Mon, 23 Jun 2008 19:11:35 -0700 Message-ID: <486058F3.3030305@sgi.com> Date: Tue, 24 Jun 2008 12:16:19 +1000 From: Lachlan McIlroy Reply-To: lachlan@sgi.com MIME-Version: 1.0 Subject: [PATCH 2/2] Restore the lowspace extent allocator algorithm Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: xfs-dev , xfs-oss When free space is running low the extent allocator may choose to allocate an extent from an AG without leaving sufficient space for a btree split when inserting the new extent (see where xfs_bmap_btalloc() sets minleft to 0). In this case the allocator will enable the lowspace algorithm which is supposed to allow further allocations (such as btree splits and newroots) to allocate from sequential AGs. This algorithm has been broken for a long time and this patch restores its behaviour. Lachlan --- 2.6.x-agno2.orig/fs/xfs/xfs_bmap_btree.c +++ 2.6.x-agno2/fs/xfs/xfs_bmap_btree.c @@ -1504,7 +1504,9 @@ xfs_bmbt_split( * we may need space for two tree splits. */ args.minleft = xfs_trans_get_block_res(args.tp); - } else + } else if (cur->bc_private.b.flist->xbf_low) + args.type = XFS_ALLOCTYPE_START_BNO; + else args.type = XFS_ALLOCTYPE_NEAR_BNO; args.mod = args.alignment = args.total = args.isfl = args.userdata = args.minalignslop = 0; @@ -2232,7 +2234,9 @@ xfs_bmbt_newroot( #endif args.fsbno = be64_to_cpu(*pp); args.type = XFS_ALLOCTYPE_START_BNO; - } else + } else if (cur->bc_private.b.flist->xbf_low) + args.type = XFS_ALLOCTYPE_START_BNO; + else args.type = XFS_ALLOCTYPE_NEAR_BNO; if ((error = xfs_alloc_vextent(&args))) { XFS_BMBT_TRACE_CURSOR(cur, ERROR);