From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:43167 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752533AbcI3DLD (ORCPT ); Thu, 29 Sep 2016 23:11:03 -0400 Subject: [PATCH 49/63] xfs: don't allow reflink when the AG is low on space From: "Darrick J. Wong" To: david@fromorbit.com, darrick.wong@oracle.com Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Date: Thu, 29 Sep 2016 20:10:58 -0700 Message-ID: <147520505883.29434.18153308905938659361.stgit@birch.djwong.org> In-Reply-To: <147520472904.29434.15518629624221621056.stgit@birch.djwong.org> References: <147520472904.29434.15518629624221621056.stgit@birch.djwong.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: If the AG free space is down to the reserves, refuse to reflink our way out of space. Hopefully userspace will make a real copy and/or go elsewhere. Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_reflink.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 75d49df..a0c5ada 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -54,6 +54,8 @@ #include "xfs_reflink.h" #include "xfs_iomap.h" #include "xfs_rmap_btree.h" +#include "xfs_sb.h" +#include "xfs_ag_resv.h" /* * Copy on Write of Shared Blocks @@ -1108,6 +1110,31 @@ xfs_reflink_update_dest( } /* + * Do we have enough reserve in this AG to handle a reflink? The refcount + * btree already reserved all the space it needs, but the rmap btree can grow + * infinitely, so we won't allow more reflinks when the AG is down to the + * btree reserves. + */ +static int +xfs_reflink_ag_has_free_space( + struct xfs_mount *mp, + xfs_agnumber_t agno) +{ + struct xfs_perag *pag; + int error = 0; + + if (!xfs_sb_version_hasrmapbt(&mp->m_sb)) + return 0; + + pag = xfs_perag_get(mp, agno); + if (xfs_ag_resv_critical(pag, XFS_AG_RESV_AGFL) || + xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA)) + error = -ENOSPC; + xfs_perag_put(pag); + return error; +} + +/* * Unmap a range of blocks from a file, then map other blocks into the hole. * The range to unmap is (destoff : destoff + srcioff + irec->br_blockcount). * The extent irec is mapped into dest at irec->br_startoff. @@ -1139,6 +1166,14 @@ xfs_reflink_remap_extent( irec->br_startblock != DELAYSTARTBLOCK && !ISUNWRITTEN(irec)); + /* No reflinking if we're low on space */ + if (real_extent) { + error = xfs_reflink_ag_has_free_space(mp, + XFS_FSB_TO_AGNO(mp, irec->br_startblock)); + if (error) + goto out; + } + /* Start a rolling transaction to switch the mappings */ resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK); error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);