From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2120.oracle.com ([156.151.31.85]:57264 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727546AbeKHC00 (ORCPT ); Wed, 7 Nov 2018 21:26:26 -0500 Date: Wed, 7 Nov 2018 08:55:08 -0800 From: "Darrick J. Wong" Subject: Re: [PATCH 03/16] xfs: finobt AG reserves don't consider last AG can be a runt Message-ID: <20181107165508.GA4135@magnolia> References: <20181107063127.3902-1-david@fromorbit.com> <20181107063127.3902-4-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181107063127.3902-4-david@fromorbit.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org On Wed, Nov 07, 2018 at 05:31:14PM +1100, Dave Chinner wrote: > From: Dave Chinner > > The last AG may be very small comapred to all other AGs, and hence > AG reservations based on the superblock AG size may actually consume > more space than the AG actually has. This results on assert failures > like: > > XFS: Assertion failed: xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved + xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <= pag->pagf_freeblks + pag->pagf_flcount, file: fs/xfs/libxfs/xfs_ag_resv.c, line: 319 > [ 48.932891] xfs_ag_resv_init+0x1bd/0x1d0 > [ 48.933853] xfs_fs_reserve_ag_blocks+0x37/0xb0 > [ 48.934939] xfs_mountfs+0x5b3/0x920 > [ 48.935804] xfs_fs_fill_super+0x462/0x640 > [ 48.936784] ? xfs_test_remount_options+0x60/0x60 > [ 48.937908] mount_bdev+0x178/0x1b0 > [ 48.938751] mount_fs+0x36/0x170 > [ 48.939533] vfs_kern_mount.part.43+0x54/0x130 > [ 48.940596] do_mount+0x20e/0xcb0 > [ 48.941396] ? memdup_user+0x3e/0x70 > [ 48.942249] ksys_mount+0xba/0xd0 > [ 48.943046] __x64_sys_mount+0x21/0x30 > [ 48.943953] do_syscall_64+0x54/0x170 > [ 48.944835] entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Hence we need to ensure the finobt per-ag space reservations take > into account the size of the last AG rather than treat it like all > the other full size AGs. > > Note that both refcountbt and rmapbt already take the size of the AG > into account via reading the AGF length directly. > > Signed-off-by: Dave Chinner > --- > fs/xfs/libxfs/xfs_ialloc_btree.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c > index 86c50208a143..62014780d5e4 100644 > --- a/fs/xfs/libxfs/xfs_ialloc_btree.c > +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c > @@ -538,15 +538,24 @@ xfs_inobt_rec_check_count( > > static xfs_extlen_t > xfs_inobt_max_size( > - struct xfs_mount *mp) > + struct xfs_mount *mp, > + xfs_agnumber_t agno) > { > + uint32_t agblocks = mp->m_sb.sb_agblocks; > + > /* Bail out if we're uninitialized, which can happen in mkfs. */ > if (mp->m_inobt_mxr[0] == 0) > return 0; > > + /* last AG can be a runt */ > + if (agno == mp->m_sb.sb_agcount - 1) { > + div_u64_rem(mp->m_sb.sb_dblocks, mp->m_sb.sb_agblocks, > + &agblocks); > + } Why not: agblocks = xfs_ag_block_count(mp, agno); ? --D > + > return xfs_btree_calc_size(mp->m_inobt_mnr, > - (uint64_t)mp->m_sb.sb_agblocks * mp->m_sb.sb_inopblock / > - XFS_INODES_PER_CHUNK); > + (uint64_t)agblocks * mp->m_sb.sb_inopblock / > + XFS_INODES_PER_CHUNK); > } > > static int > @@ -594,7 +603,7 @@ xfs_finobt_calc_reserves( > if (error) > return error; > > - *ask += xfs_inobt_max_size(mp); > + *ask += xfs_inobt_max_size(mp, agno); > *used += tree_len; > return 0; > } > -- > 2.19.1 >