qemu-kvm/kvm-migration-block-Fix-possible-race-with-block_inactiv.patch
Miroslav Rezanina a583c50c4e * Mon Feb 17 2025 Miroslav Rezanina <mrezanin@redhat.com> - 9.1.0-15
- kvm-migration-Add-helper-to-get-target-runstate.patch [RHEL-54670]
- kvm-qmp-cont-Only-activate-disks-if-migration-completed.patch [RHEL-54670]
- kvm-migration-block-Make-late-block-active-the-default.patch [RHEL-54670]
- kvm-migration-block-Apply-late-block-active-behavior-to-.patch [RHEL-54670]
- kvm-migration-block-Fix-possible-race-with-block_inactiv.patch [RHEL-54670]
- kvm-migration-block-Rewrite-disk-activation.patch [RHEL-54670]
- kvm-block-Add-active-field-to-BlockDeviceInfo.patch [RHEL-54670]
- kvm-block-Allow-inactivating-already-inactive-nodes.patch [RHEL-54670]
- kvm-block-Inactivate-external-snapshot-overlays-when-nec.patch [RHEL-54670]
- kvm-migration-block-active-Remove-global-active-flag.patch [RHEL-54670]
- kvm-block-Don-t-attach-inactive-child-to-active-node.patch [RHEL-54670]
- kvm-block-Fix-crash-on-block_resize-on-inactive-node.patch [RHEL-54670]
- kvm-block-Add-option-to-create-inactive-nodes.patch [RHEL-54670]
- kvm-block-Add-blockdev-set-active-QMP-command.patch [RHEL-54670]
- kvm-block-Support-inactive-nodes-in-blk_insert_bs.patch [RHEL-54670]
- kvm-block-export-Don-t-ignore-image-activation-error-in-.patch [RHEL-54670]
- kvm-block-Drain-nodes-before-inactivating-them.patch [RHEL-54670]
- kvm-block-export-Add-option-to-allow-export-of-inactive-.patch [RHEL-54670]
- kvm-nbd-server-Support-inactive-nodes.patch [RHEL-54670]
- kvm-iotests-Add-filter_qtest.patch [RHEL-54670]
- kvm-iotests-Add-qsd-migrate-case.patch [RHEL-54670]
- kvm-iotests-Add-NBD-based-tests-for-inactive-nodes.patch [RHEL-54670]
- Resolves: RHEL-54670
  (Provide QMP command for block device reactivation after migration [rhel-10.0])
2025-02-17 03:54:53 -05:00

79 lines
3.0 KiB
Diff

From 3c6e09fe92972513d38c15c03db29a6843e44d3d Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Fri, 6 Dec 2024 18:08:37 -0500
Subject: [PATCH 05/22] migration/block: Fix possible race with block_inactive
RH-Author: Kevin Wolf <kwolf@redhat.com>
RH-MergeRequest: 340: QMP command for block device reactivation after migration
RH-Jira: RHEL-54670
RH-Acked-by: Eric Blake <eblake@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [5/22] a88a20817cb28674367cc57dfe16e6c60c7122b1 (kmwolf/centos-qemu-kvm)
Src QEMU sets block_inactive=true very early before the invalidation takes
place. It means if something wrong happened during setting the flag but
before reaching qemu_savevm_state_complete_precopy_non_iterable() where it
did the invalidation work, it'll make block_inactive flag inconsistent.
For example, think about when qemu_savevm_state_complete_precopy_iterable()
can fail: it will have block_inactive set to true even if all block drives
are active.
Fix that by only update the flag after the invalidation is done.
No Fixes for any commit, because it's not an issue if bdrv_activate_all()
is re-entrant upon all-active disks - false positive block_inactive can
bring nothing more than "trying to active the blocks but they're already
active". However let's still do it right to avoid the inconsistent flag
v.s. reality.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Message-Id: <20241206230838.1111496-6-peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
(cherry picked from commit 8c97c5a476d146b35b2873ef73df601216a494d9)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
migration/migration.c | 9 +++------
migration/savevm.c | 2 ++
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index 8a262e01ff..784b7e9b90 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2779,14 +2779,11 @@ static int migration_completion_precopy(MigrationState *s,
goto out_unlock;
}
- /*
- * Inactivate disks except in COLO, and track that we have done so in order
- * to remember to reactivate them if migration fails or is cancelled.
- */
- s->block_inactive = !migrate_colo();
migration_rate_set(RATE_LIMIT_DISABLED);
+
+ /* Inactivate disks except in COLO */
ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false,
- s->block_inactive);
+ !migrate_colo());
out_unlock:
bql_unlock();
return ret;
diff --git a/migration/savevm.c b/migration/savevm.c
index a0c4befdc1..b88dadd904 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1577,6 +1577,8 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
qemu_file_set_error(f, ret);
return ret;
}
+ /* Remember that we did this */
+ s->block_inactive = true;
}
if (!in_postcopy) {
/* Postcopy stream will still be going */
--
2.39.3