* [Qemu-devel] [PATCH 1/2] block: change parent backing link when *tqe_prev == NULL
2016-01-30 5:17 [Qemu-devel] [PATCH 0/2] Active commit regression fix Jeff Cody
@ 2016-01-30 5:17 ` Jeff Cody
2016-02-01 21:43 ` [Qemu-devel] [Qemu-block] " Max Reitz
2016-01-30 5:17 ` [Qemu-devel] [PATCH 2/2] block: qemu-iotests - add test for snapshot, commit, snapshot bug Jeff Cody
2016-02-01 20:35 ` [Qemu-devel] [PATCH 0/2] Active commit regression fix Eric Blake
2 siblings, 1 reply; 6+ messages in thread
From: Jeff Cody @ 2016-01-30 5:17 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, qemu-stable, qemu-block
In change_parent_backing_link(), we only inserted the new
BlockDriverState entry into the device_list if the tqe_prev pointer was
NULL. However, we must also allow insertion when the BDS pointed
to by the tqe_prev pointer is NULL as well.
This fixes a bug with external snapshots, and live active layer commits.
After a live snapshot occurs, the active layer and the base layer both
have a non-NULL tqe_prev field in the device_list, although the base
node's tqe_prev field points to a NULL entry.
Once the active commit is finished, bdrv_replace_in_backing_chain() is
called to set the base node as the new active node, and remove the
node that was the prior active layer from the device_list.
If we only check against the tqe_prev pointer field and not the entity
it is pointing to, then we fail to insert base image into the device
list. The previous active layer is still removed from the device_list,
leaving an empty device_list queue.
With an empty device_list queue, odd behavior occurs - such as not
allowing any more live snapshots.
This commit fixes this issue, by checking for a NULL tqe_prev entity
in the devices_list.
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
block.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 5709d3d..0b8526b 100644
--- a/block.c
+++ b/block.c
@@ -2272,7 +2272,7 @@ static void change_parent_backing_link(BlockDriverState *from,
}
if (from->blk) {
blk_set_bs(from->blk, to);
- if (!to->device_list.tqe_prev) {
+ if (!to->device_list.tqe_prev || !*to->device_list.tqe_prev) {
QTAILQ_INSERT_BEFORE(from, to, device_list);
}
QTAILQ_REMOVE(&bdrv_states, from, device_list);
--
1.9.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* [Qemu-devel] [PATCH 2/2] block: qemu-iotests - add test for snapshot, commit, snapshot bug
2016-01-30 5:17 [Qemu-devel] [PATCH 0/2] Active commit regression fix Jeff Cody
2016-01-30 5:17 ` [Qemu-devel] [PATCH 1/2] block: change parent backing link when *tqe_prev == NULL Jeff Cody
@ 2016-01-30 5:17 ` Jeff Cody
2016-02-01 20:35 ` [Qemu-devel] [PATCH 0/2] Active commit regression fix Eric Blake
2 siblings, 0 replies; 6+ messages in thread
From: Jeff Cody @ 2016-01-30 5:17 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, qemu-stable, qemu-block
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
tests/qemu-iotests/143 | 114 +++++++++++++++++++++++++++++++++++++++++++++
tests/qemu-iotests/143.out | 24 ++++++++++
tests/qemu-iotests/group | 1 +
3 files changed, 139 insertions(+)
create mode 100755 tests/qemu-iotests/143
create mode 100644 tests/qemu-iotests/143.out
diff --git a/tests/qemu-iotests/143 b/tests/qemu-iotests/143
new file mode 100755
index 0000000..6f3e0bb
--- /dev/null
+++ b/tests/qemu-iotests/143
@@ -0,0 +1,114 @@
+#!/bin/bash
+# Check live snapshot, followed by active commit, and another snapshot.
+#
+# This test is to catch the error case of BZ #1300209:
+# https://bugzilla.redhat.com/show_bug.cgi?id=1300209
+#
+# Copyright (C) 2016 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=jcody@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+status=1 # failure is the default!
+
+TMP_SNAP1=${TEST_DIR}/tmp.qcow2
+TMP_SNAP2=${TEST_DIR}/tmp2.qcow2
+
+_cleanup()
+{
+ _cleanup_qemu
+ rm -f "${TEST_IMG}" "${TMP_SNAP1}" "${TMP_SNAP2}"
+}
+
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.qemu
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+size=512M
+
+_make_test_img $size
+
+echo
+echo === Launching QEMU ===
+echo
+
+qemu_comm_method="qmp"
+_launch_qemu -drive file="${TEST_IMG}",if=virtio
+h=$QEMU_HANDLE
+
+
+echo
+echo === Performing Live Snapshot 1 ===
+echo
+
+_send_qemu_cmd $h "{ 'execute': 'qmp_capabilities' }" "return"
+
+
+# First live snapshot, new overlay as active layer
+_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot-sync',
+ 'arguments': {
+ 'device': 'virtio0',
+ 'snapshot-file':'${TMP_SNAP1}',
+ 'format': 'qcow2'
+ }
+ }" "return"
+
+echo
+echo === Performing block-commit on active layer ===
+echo
+
+# Block commit on active layer, push the new overlay into base
+_send_qemu_cmd $h "{ 'execute': 'block-commit',
+ 'arguments': {
+ 'device': 'virtio0'
+ }
+ }" "READY"
+
+_send_qemu_cmd $h "{ 'execute': 'block-job-complete',
+ 'arguments': {
+ 'device': 'virtio0'
+ }
+ }" "COMPLETED"
+
+echo
+echo === Performing Live Snapshot 2 ===
+echo
+
+# New live snapshot, new overlays as active layer
+_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot-sync',
+ 'arguments': {
+ 'device': 'virtio0',
+ 'snapshot-file':'${TMP_SNAP2}',
+ 'format': 'qcow2'
+ }
+ }" "return"
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/143.out b/tests/qemu-iotests/143.out
new file mode 100644
index 0000000..05cc9f4
--- /dev/null
+++ b/tests/qemu-iotests/143.out
@@ -0,0 +1,24 @@
+QA output created by 143
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=536870912
+
+=== Launching QEMU ===
+
+
+=== Performing Live Snapshot 1 ===
+
+{"return": {}}
+Formatting 'TEST_DIR/tmp.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/t.qcow2 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
+{"return": {}}
+
+=== Performing block-commit on active layer ===
+
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "virtio0", "len": 0, "offset": 0, "speed": 0, "type": "commit"}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "virtio0", "len": 0, "offset": 0, "speed": 0, "type": "commit"}}
+
+=== Performing Live Snapshot 2 ===
+
+Formatting 'TEST_DIR/tmp2.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/t.qcow2 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
+{"return": {}}
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index d6e9219..9203a4d 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -142,3 +142,4 @@
138 rw auto quick
139 rw auto quick
142 auto
+143 rw auto quick
--
1.9.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH 0/2] Active commit regression fix
2016-01-30 5:17 [Qemu-devel] [PATCH 0/2] Active commit regression fix Jeff Cody
2016-01-30 5:17 ` [Qemu-devel] [PATCH 1/2] block: change parent backing link when *tqe_prev == NULL Jeff Cody
2016-01-30 5:17 ` [Qemu-devel] [PATCH 2/2] block: qemu-iotests - add test for snapshot, commit, snapshot bug Jeff Cody
@ 2016-02-01 20:35 ` Eric Blake
2 siblings, 0 replies; 6+ messages in thread
From: Eric Blake @ 2016-02-01 20:35 UTC (permalink / raw)
To: Jeff Cody, qemu-devel; +Cc: kwolf, qemu-stable, qemu-block
[-- Attachment #1: Type: text/plain, Size: 1030 bytes --]
On 01/29/2016 10:17 PM, Jeff Cody wrote:
> Bug #1300209 is a regression in 2.5, introduced during the
> change away from bdrv_swap().
>
> When we change the parent backing link (change_parent_backing_link),
> we must also accomodate non-NULL tqe_prev pointers that point to a
> NULL entry. Please see patch #1 for more details.
>
> Jeff Cody (2):
> block: change parent backing link when *tqe_prev == NULL
> block: qemu-iotests - add test for snapshot, commit, snapshot bug
Series:
Reviewed-by: Eric Blake <eblake@redhat.com>
>
> block.c | 2 +-
> tests/qemu-iotests/143 | 114 +++++++++++++++++++++++++++++++++++++++++++++
> tests/qemu-iotests/143.out | 24 ++++++++++
> tests/qemu-iotests/group | 1 +
> 4 files changed, 140 insertions(+), 1 deletion(-)
> create mode 100755 tests/qemu-iotests/143
> create mode 100644 tests/qemu-iotests/143.out
>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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^ permalink raw reply [flat|nested] 6+ messages in thread