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qemu: fix race between disk mirror fail and cancel

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If a VM migration is aborted, a disk mirror may be failed by QEMU before
libvirt has a chance to cancel it. The disk->mirrorState remains at
_ABORT in this case, and this breaks subsequent mirrorings of that disk.

We should instead check the mirrorState directly and transition to _NONE
if it is already aborted. Do the check *after* aborting the block job in
QEMU to avoid a race.

Signed-off-by: Michael Chapman <mike@very.puzzling.org>
(cherry picked from commit e5d729ba42d86eb3afa9799bca2944700fde41bb)
This commit is contained in:
Michael Chapman 2015-03-30 13:41:00 +11:00 committed by Cole Robinson
parent 188e536739
commit 9a0e0d3f17
1 changed files with 8 additions and 0 deletions
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8
src/qemu/qemu_migration.c
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@ -1852,6 +1852,10 @@ qemuMigrationDriveMirror(virQEMUDriverPtr driver,
} else {
VIR_WARN("Unable to enter monitor. No block job cancelled");
}
/* If disk mirror is already aborted, clear the mirror state now */
if (disk->mirrorState == VIR_DOMAIN_DISK_MIRROR_STATE_ABORT)
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_NONE;
}
if (err)
virSetError(err);
@ -1920,6 +1924,10 @@ qemuMigrationCancelDriveMirror(qemuMigrationCookiePtr mig,
ret = -1;
goto cleanup;
}
/* If disk mirror is already aborted, clear the mirror state now */
if (disk->mirrorState == VIR_DOMAIN_DISK_MIRROR_STATE_ABORT)
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_NONE;
}
cleanup: