[libvirt] [PATCH] qemu: blockjob: Reset disk source index after pivot

Since we are re-detecting the backing chain after pivoting to the active block commit target (or block copy target) the disk index needs to be reset to 0. This is necessary since we move a member of the backing chain to disk->src but clear indexes only starting from disk->src->backingStore. The freshly detected images have indexes starting from 1, but since we've pivoted into an image which was previously a backing store it would have a non-0 index. The lookup function would then return the top of the chain for queries like 'vda[1]' instead of the first backing store. This problem will not be present once we keep the disk indexes stable. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1519745 --- src/qemu/qemu_blockjob.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/qemu/qemu_blockjob.c b/src/qemu/qemu_blockjob.c index 0b1616a214..617e4ee564 100644 --- a/src/qemu/qemu_blockjob.c +++ b/src/qemu/qemu_blockjob.c @@ -175,6 +175,7 @@ qemuBlockJobEventProcess(virQEMUDriverPtr driver, disk->mirror = NULL; disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_NONE; disk->mirrorJob = VIR_DOMAIN_BLOCK_JOB_TYPE_UNKNOWN; + disk->src->id = 0; ignore_value(qemuDomainDetermineDiskChain(driver, vm, disk, true, true)); ignore_value(qemuBlockNodeNamesDetect(driver, vm, asyncJob)); -- 2.15.0

On 12/07/2017 09:27 AM, Peter Krempa wrote:
Since we are re-detecting the backing chain after pivoting to the active block commit target (or block copy target) the disk index needs to be reset to 0. This is necessary since we move a member of the backing chain to disk->src but clear indexes only starting from disk->src->backingStore. The freshly detected images have indexes starting from 1, but since we've pivoted into an image which was previously a backing store it would have a non-0 index. The lookup function would then return the top of the chain for queries like 'vda[1]' instead of the first backing store.
This problem will not be present once we keep the disk indexes stable.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1519745 --- src/qemu/qemu_blockjob.c | 1 + 1 file changed, 1 insertion(+)
Reviewed-by: Eric Blake <eblake@redhat.com> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
participants (2)
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Eric Blake
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Peter Krempa