glusterfs/SOURCES/0178-Cluster-afr-Don-t-treat-all-bricks-having-metadata-p.patch

From 307074330db6e9f14941dfbabbe6f299cf841533 Mon Sep 17 00:00:00 2001
From: karthik-us <ksubrahm@redhat.com>
Date: Mon, 10 Jun 2019 23:58:16 +0530
Subject: [PATCH 178/178] Cluster/afr: Don't treat all bricks having metadata
 pending as split-brain

Backport of: https://review.gluster.org/#/c/glusterfs/+/22831/

Problem:
We currently don't have a roll-back/undoing of post-ops if quorum is not met.
Though the FOP is still unwound with failure, the xattrs remain on the disk.
Due to these partial post-ops and partial heals (healing only when 2 bricks
are up), we can end up in metadata split-brain purely from the afr xattrs
point of view i.e each brick is blamed by atleast one of the others for
metadata. These scenarios are hit when there is frequent connect/disconnect
of the client/shd to the bricks.

Fix:
Pick a source based on the xattr values. If 2 bricks blame one, the blamed
one must be treated as sink. If there is no majority, all are sources. Once
we pick a source, self-heal will then do the heal instead of erroring out
due to split-brain.
This patch also adds restriction of all the bricks to be up to perform
metadata heal to avoid any metadata loss.

Removed the test case tests/bugs/replicate/bug-1468279-source-not-blaming-sinks.t
as it was doing metadata heal even when only 2 of 3 bricks were up.

Change-Id: I02064ecb7d68d498f75a353af64f75249a633508
fixes: bz#1715438
Signed-off-by: karthik-us <ksubrahm@redhat.com>
Reviewed-on: https://code.engineering.redhat.com/gerrit/172935
Tested-by: RHGS Build Bot <nigelb@redhat.com>
Reviewed-by: Sunil Kumar Heggodu Gopala Acharya <sheggodu@redhat.com>
---
 .../bug-1468279-source-not-blaming-sinks.t         |  64 ----------
 .../bug-1717819-metadata-split-brain-detection.t   | 130 +++++++++++++++++++++
 xlators/cluster/afr/src/afr-self-heal-common.c     |   4 +-
 xlators/cluster/afr/src/afr-self-heal-metadata.c   |   2 +-
 4 files changed, 133 insertions(+), 67 deletions(-)
 delete mode 100644 tests/bugs/replicate/bug-1468279-source-not-blaming-sinks.t
 create mode 100644 tests/bugs/replicate/bug-1717819-metadata-split-brain-detection.t

diff --git a/tests/bugs/replicate/bug-1468279-source-not-blaming-sinks.t b/tests/bugs/replicate/bug-1468279-source-not-blaming-sinks.t
deleted file mode 100644
index 054a4ad..0000000
--- a/tests/bugs/replicate/bug-1468279-source-not-blaming-sinks.t
+++ /dev/null
@@ -1,64 +0,0 @@
-#!/bin/bash
-. $(dirname $0)/../../include.rc
-. $(dirname $0)/../../volume.rc
-cleanup;
-
-TEST glusterd
-TEST pidof glusterd
-TEST $CLI volume create $V0 replica 3 $H0:$B0/${V0}{0,1,2}
-TEST $CLI volume start $V0
-TEST $CLI volume set $V0 cluster.self-heal-daemon off
-TEST $CLI volume set $V0 cluster.metadata-self-heal off
-TEST $GFS --volfile-id=$V0 --volfile-server=$H0 --attribute-timeout=0 --entry-timeout=0 $M0;
-TEST touch $M0/file
-
-# Kill B1, create a pending metadata heal.
-TEST kill_brick $V0 $H0 $B0/${V0}0
-TEST setfattr -n user.xattr -v value1 $M0/file
-EXPECT "0000000000000010000000" get_hex_xattr trusted.afr.$V0-client-0 $B0/${V0}1/file
-EXPECT "0000000000000010000000" get_hex_xattr trusted.afr.$V0-client-0 $B0/${V0}2/file
-
-# Kill B2, heal from B3 to B1.
-TEST $CLI volume start $V0 force
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status $V0 0
-TEST kill_brick $V0 $H0 $B0/${V0}1
-TEST $CLI volume set $V0 cluster.self-heal-daemon on
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 2
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 0
-$CLI volume heal $V0
-EXPECT_WITHIN $HEAL_TIMEOUT  "00000000" afr_get_specific_changelog_xattr $B0/${V0}2/file trusted.afr.$V0-client-0 "metadata"
-TEST $CLI volume set $V0 cluster.self-heal-daemon off
-
-# Create another pending metadata heal.
-TEST setfattr -n user.xattr -v value2 $M0/file
-EXPECT "0000000000000010000000" get_hex_xattr trusted.afr.$V0-client-1 $B0/${V0}0/file
-EXPECT "0000000000000010000000" get_hex_xattr trusted.afr.$V0-client-1 $B0/${V0}2/file
-
-# Kill B1, heal from B3 to B2
-TEST $CLI volume start $V0 force
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status $V0 1
-TEST kill_brick $V0 $H0 $B0/${V0}0
-TEST $CLI volume set $V0 cluster.self-heal-daemon on
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 2
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 1
-$CLI volume heal $V0
-EXPECT_WITHIN $HEAL_TIMEOUT  "00000000" afr_get_specific_changelog_xattr $B0/${V0}2/file trusted.afr.$V0-client-1 "metadata"
-TEST $CLI volume set $V0 cluster.self-heal-daemon off
-
-# ALL bricks up again.
-TEST $CLI volume start $V0 force
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status $V0 1
-EXPECT_WITHIN $PROCESS_UP_TIMEOUT "1" afr_child_up_status $V0 1
-# B1 and B2 blame each other, B3 doesn't blame anyone.
-EXPECT "0000000000000010000000" get_hex_xattr trusted.afr.$V0-client-1 $B0/${V0}0/file
-EXPECT "0000000000000010000000" get_hex_xattr trusted.afr.$V0-client-0 $B0/${V0}1/file
-EXPECT "0000000000000000000000" get_hex_xattr trusted.afr.$V0-client-0 $B0/${V0}2/file
-EXPECT "0000000000000000000000" get_hex_xattr trusted.afr.$V0-client-1 $B0/${V0}2/file
-TEST $CLI volume set $V0 cluster.self-heal-daemon on
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 0
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 1
-EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 2
-TEST $CLI volume heal $V0
-EXPECT_WITHIN $HEAL_TIMEOUT "^0$" get_pending_heal_count $V0
-
-cleanup;
diff --git a/tests/bugs/replicate/bug-1717819-metadata-split-brain-detection.t b/tests/bugs/replicate/bug-1717819-metadata-split-brain-detection.t
new file mode 100644
index 0000000..94b8bf3
--- /dev/null
+++ b/tests/bugs/replicate/bug-1717819-metadata-split-brain-detection.t
@@ -0,0 +1,130 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+. $(dirname $0)/../../afr.rc
+
+cleanup;
+
+## Start and create a volume
+TEST glusterd;
+TEST pidof glusterd;
+TEST $CLI volume info;
+
+TEST $CLI volume create $V0 replica 3 $H0:$B0/${V0}{0,1,2};
+TEST $CLI volume start $V0;
+EXPECT 'Started' volinfo_field $V0 'Status';
+TEST $CLI volume heal $V0 disable
+TEST $GFS --volfile-id=/$V0 --volfile-server=$H0 $M0
+
+###############################################################################
+# Case of 2 bricks blaming the third and the third blaming the other two.
+
+TEST mkdir $M0/dir
+
+# B0 and B2 must blame B1
+TEST kill_brick $V0 $H0 $B0/$V0"1"
+TEST setfattr -n user.metadata -v 1 $M0/dir
+EXPECT "00000001" afr_get_specific_changelog_xattr $B0/${V0}0/dir trusted.afr.$V0-client-1 metadata
+EXPECT "00000001" afr_get_specific_changelog_xattr $B0/${V0}2/dir trusted.afr.$V0-client-1 metadata
+CLIENT_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $M0/dir)
+
+# B1 must blame B0 and B2
+setfattr -n trusted.afr.$V0-client-0 -v 0x000000000000000100000000 $B0/$V0"1"/dir
+setfattr -n trusted.afr.$V0-client-2 -v 0x000000000000000100000000 $B0/$V0"1"/dir
+
+# Launch heal
+TEST $CLI volume start $V0 force
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT "^1$" brick_up_status $V0 $H0 $B0/${V0}1
+TEST $CLI volume heal $V0 enable
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT "^Y$" glustershd_up_status
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "^1$" afr_child_up_status_in_shd $V0 0
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "^1$" afr_child_up_status_in_shd $V0 1
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "^1$" afr_child_up_status_in_shd $V0 2
+TEST $CLI volume heal $V0
+EXPECT_WITHIN $HEAL_TIMEOUT "^0$" get_pending_heal_count $V0
+
+B0_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}0/dir)
+B1_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}1/dir)
+B2_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}2/dir)
+
+TEST [ "$CLIENT_XATTR" == "$B0_XATTR" ]
+TEST [ "$CLIENT_XATTR" == "$B1_XATTR" ]
+TEST [ "$CLIENT_XATTR" == "$B2_XATTR" ]
+TEST setfattr -x user.metadata $M0/dir
+
+###############################################################################
+# Case of each brick blaming the next one in a cyclic manner
+
+TEST $CLI volume heal $V0 disable
+TEST `echo "hello" >> $M0/dir/file`
+# Mark cyclic xattrs and modify metadata directly on the bricks.
+setfattr -n trusted.afr.$V0-client-1 -v 0x000000000000000100000000 $B0/$V0"0"/dir/file
+setfattr -n trusted.afr.$V0-client-2 -v 0x000000000000000100000000 $B0/$V0"1"/dir/file
+setfattr -n trusted.afr.$V0-client-0 -v 0x000000000000000100000000 $B0/$V0"2"/dir/file
+
+setfattr -n user.metadata -v 1 $B0/$V0"0"/dir/file
+setfattr -n user.metadata -v 2 $B0/$V0"1"/dir/file
+setfattr -n user.metadata -v 3 $B0/$V0"2"/dir/file
+
+# Add entry to xattrop dir to trigger index heal.
+xattrop_dir0=$(afr_get_index_path $B0/$V0"0")
+base_entry_b0=`ls $xattrop_dir0`
+gfid_str=$(gf_gfid_xattr_to_str $(gf_get_gfid_xattr $B0/$V0"0"/dir/file))
+ln $xattrop_dir0/$base_entry_b0 $xattrop_dir0/$gfid_str
+EXPECT_WITHIN $HEAL_TIMEOUT "^1$" get_pending_heal_count $V0
+
+# Launch heal
+TEST $CLI volume heal $V0 enable
+TEST $CLI volume heal $V0
+EXPECT_WITHIN $HEAL_TIMEOUT "^0$" get_pending_heal_count $V0
+
+B0_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}0/dir/file)
+B1_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}1/dir/file)
+B2_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}2/dir/file)
+
+TEST [ "$B0_XATTR" == "$B1_XATTR" ]
+TEST [ "$B0_XATTR" == "$B2_XATTR" ]
+TEST rm -f $M0/dir/file
+
+###############################################################################
+# Case of 2 bricks having quorum blaming and the other having only one blaming.
+
+TEST $CLI volume heal $V0 disable
+TEST `echo "hello" >> $M0/dir/file`
+# B0 and B2 must blame B1
+TEST kill_brick $V0 $H0 $B0/$V0"1"
+TEST setfattr -n user.metadata -v 1 $M0/dir/file
+EXPECT "00000001" afr_get_specific_changelog_xattr $B0/${V0}0/dir/file trusted.afr.$V0-client-1 metadata
+EXPECT "00000001" afr_get_specific_changelog_xattr $B0/${V0}2/dir/file trusted.afr.$V0-client-1 metadata
+
+# B1 must blame B0 and B2
+setfattr -n trusted.afr.$V0-client-0 -v 0x000000000000000100000000 $B0/$V0"1"/dir/file
+setfattr -n trusted.afr.$V0-client-2 -v 0x000000000000000100000000 $B0/$V0"1"/dir/file
+
+# B0 must blame B2
+setfattr -n trusted.afr.$V0-client-2 -v 0x000000000000000100000000 $B0/$V0"0"/dir/file
+
+# Modify the metadata directly on the bricks B1 & B2.
+setfattr -n user.metadata -v 2 $B0/$V0"1"/dir/file
+setfattr -n user.metadata -v 3 $B0/$V0"2"/dir/file
+
+# Launch heal
+TEST $CLI volume start $V0 force
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT "^1$" brick_up_status $V0 $H0 $B0/${V0}1
+TEST $CLI volume heal $V0 enable
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT "^Y$" glustershd_up_status
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "^1$" afr_child_up_status_in_shd $V0 0
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "^1$" afr_child_up_status_in_shd $V0 1
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "^1$" afr_child_up_status_in_shd $V0 2
+
+B0_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}0/dir/file)
+B1_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}1/dir/file)
+B2_XATTR=$(getfattr -n 'user.metadata' --absolute-names --only-values $B0/${V0}2/dir/file)
+
+TEST [ "$B0_XATTR" == "$B1_XATTR" ]
+TEST [ "$B0_XATTR" == "$B2_XATTR" ]
+
+###############################################################################
+
+cleanup
diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c
index 595bed4..5157e7d 100644
--- a/xlators/cluster/afr/src/afr-self-heal-common.c
+++ b/xlators/cluster/afr/src/afr-self-heal-common.c
@@ -1590,7 +1590,7 @@ afr_selfheal_find_direction(call_frame_t *frame, xlator_t *this,
         }
     }
 
-    if (type == AFR_DATA_TRANSACTION) {
+    if (type == AFR_DATA_TRANSACTION || type == AFR_METADATA_TRANSACTION) {
         min_participants = priv->child_count;
     } else {
         min_participants = AFR_SH_MIN_PARTICIPANTS;
@@ -1656,7 +1656,7 @@ afr_selfheal_find_direction(call_frame_t *frame, xlator_t *this,
         }
     }
 
-    if (type == AFR_DATA_TRANSACTION)
+    if (type == AFR_DATA_TRANSACTION || type == AFR_METADATA_TRANSACTION)
         afr_selfheal_post_op_failure_accounting(priv, accused, sources,
                                                 locked_on);
 
diff --git a/xlators/cluster/afr/src/afr-self-heal-metadata.c b/xlators/cluster/afr/src/afr-self-heal-metadata.c
index ba43341..ecfa791 100644
--- a/xlators/cluster/afr/src/afr-self-heal-metadata.c
+++ b/xlators/cluster/afr/src/afr-self-heal-metadata.c
@@ -398,7 +398,7 @@ afr_selfheal_metadata(call_frame_t *frame, xlator_t *this, inode_t *inode)
     ret = afr_selfheal_inodelk(frame, this, inode, this->name, LLONG_MAX - 1, 0,
                                data_lock);
     {
-        if (ret < AFR_SH_MIN_PARTICIPANTS) {
+        if (ret < priv->child_count) {
             ret = -ENOTCONN;
             goto unlock;
         }
-- 
1.8.3.1