From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:53631 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932226AbcEKMsO (ORCPT ); Wed, 11 May 2016 08:48:14 -0400 Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 85D59AC8A for ; Wed, 11 May 2016 12:48:12 +0000 (UTC) From: David Sterba To: stable@vger.kernel.org Subject: [PATCH 14/17] btrfs: handle non-fatal errors in btrfs_qgroup_inherit() Date: Wed, 11 May 2016 14:47:51 +0200 Message-Id: <1462970871-17281-1-git-send-email-dsterba@suse.com> In-Reply-To: <20160511124536.GB29353@suse.cz> References: <20160511124536.GB29353@suse.cz> Sender: stable-owner@vger.kernel.org List-ID: From: Mark Fasheh commit 918c2ee103cf9956f1c61d3f848dbb49fd2d104a upstream. create_pending_snapshot() will go readonly on _any_ error return from btrfs_qgroup_inherit(). If qgroups are enabled, a user can crash their fs by just making a snapshot and asking it to inherit from an invalid qgroup. For example: $ btrfs sub snap -i 1/10 /btrfs/ /btrfs/foo Will cause a transaction abort. Fix this by only throwing errors in btrfs_qgroup_inherit() when we know going readonly is acceptable. The following xfstests test case reproduces this bug: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" here=`pwd` tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { cd / rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # remove previous $seqres.full before test rm -f $seqres.full # real QA test starts here _supported_fs btrfs _supported_os Linux _require_scratch rm -f $seqres.full _scratch_mkfs _scratch_mount _run_btrfs_util_prog quota enable $SCRATCH_MNT # The qgroup '1/10' does not exist and should be silently ignored _run_btrfs_util_prog subvolume snapshot -i 1/10 $SCRATCH_MNT $SCRATCH_MNT/snap1 _scratch_unmount echo "Silence is golden" status=0 exit Signed-off-by: Mark Fasheh Reviewed-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/qgroup.c | 54 ++++++++++++++++++++++++++++++++---------------------- 1 file changed, 32 insertions(+), 22 deletions(-) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 5279fdae7142..7173360eea7a 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1842,8 +1842,10 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans, } /* - * copy the acounting information between qgroups. This is necessary when a - * snapshot or a subvolume is created + * Copy the acounting information between qgroups. This is necessary + * when a snapshot or a subvolume is created. Throwing an error will + * cause a transaction abort so we take extra care here to only error + * when a readonly fs is a reasonable outcome. */ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, u64 srcid, u64 objectid, @@ -1873,15 +1875,15 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, 2 * inherit->num_excl_copies; for (i = 0; i < nums; ++i) { srcgroup = find_qgroup_rb(fs_info, *i_qgroups); - if (!srcgroup) { - ret = -EINVAL; - goto out; - } - if ((srcgroup->qgroupid >> 48) <= (objectid >> 48)) { - ret = -EINVAL; - goto out; - } + /* + * Zero out invalid groups so we can ignore + * them later. + */ + if (!srcgroup || + ((srcgroup->qgroupid >> 48) <= (objectid >> 48))) + *i_qgroups = 0ULL; + ++i_qgroups; } } @@ -1916,17 +1918,19 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, */ if (inherit) { i_qgroups = (u64 *)(inherit + 1); - for (i = 0; i < inherit->num_qgroups; ++i) { + for (i = 0; i < inherit->num_qgroups; ++i, ++i_qgroups) { + if (*i_qgroups == 0) + continue; ret = add_qgroup_relation_item(trans, quota_root, objectid, *i_qgroups); - if (ret) + if (ret && ret != -EEXIST) goto out; ret = add_qgroup_relation_item(trans, quota_root, *i_qgroups, objectid); - if (ret) + if (ret && ret != -EEXIST) goto out; - ++i_qgroups; } + ret = 0; } @@ -1987,17 +1991,22 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, i_qgroups = (u64 *)(inherit + 1); for (i = 0; i < inherit->num_qgroups; ++i) { - ret = add_relation_rb(quota_root->fs_info, objectid, - *i_qgroups); - if (ret) - goto unlock; + if (*i_qgroups) { + ret = add_relation_rb(quota_root->fs_info, objectid, + *i_qgroups); + if (ret) + goto unlock; + } ++i_qgroups; } - for (i = 0; i < inherit->num_ref_copies; ++i) { + for (i = 0; i < inherit->num_ref_copies; ++i, i_qgroups += 2) { struct btrfs_qgroup *src; struct btrfs_qgroup *dst; + if (!i_qgroups[0] || !i_qgroups[1]) + continue; + src = find_qgroup_rb(fs_info, i_qgroups[0]); dst = find_qgroup_rb(fs_info, i_qgroups[1]); @@ -2008,12 +2017,14 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, dst->rfer = src->rfer - level_size; dst->rfer_cmpr = src->rfer_cmpr - level_size; - i_qgroups += 2; } - for (i = 0; i < inherit->num_excl_copies; ++i) { + for (i = 0; i < inherit->num_excl_copies; ++i, i_qgroups += 2) { struct btrfs_qgroup *src; struct btrfs_qgroup *dst; + if (!i_qgroups[0] || !i_qgroups[1]) + continue; + src = find_qgroup_rb(fs_info, i_qgroups[0]); dst = find_qgroup_rb(fs_info, i_qgroups[1]); @@ -2024,7 +2035,6 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, dst->excl = src->excl + level_size; dst->excl_cmpr = src->excl_cmpr + level_size; - i_qgroups += 2; } unlock: -- 2.7.1