[PATCH v2 11/19] qemu: block: Implement helpers for dealing with bitmaps during block commit

[Eric Blake]

On 3/11/20 7:55 AM, Peter Krempa wrote:
> qemuBlockBitmapsHandleCommitStart prepares for disabling the bitmaps in
> the 'base' of the commit job so that the bitmaps are not dirtied by the
> commit job. This needs to be done prior to start of the commit job.
> 
> qemuBlockBitmapsHandleCommitFinish then calculates the necessary merges
> that agregate all the bitmaps between the commited images and write them
> into the base bitmap.
> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---
>   src/qemu/qemu_block.c | 219 ++++++++++++++++++++++++++++++++++++++++++
>   src/qemu/qemu_block.h |  14 +++
>   2 files changed, 233 insertions(+)
> 
> diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
> index edebbcd0ce..6853c021ca 100644
> --- a/src/qemu/qemu_block.c
> +++ b/src/qemu/qemu_block.c
> @@ -2962,6 +2962,225 @@ qemuBlockBitmapsHandleBlockcopy(virStorageSourcePtr src,
>   }
> 
> 
> +/**
> + * @topsrc: virStorageSource representing 'top' of the job
> + * @basesrc: virStorageSource representing 'base' of the job
> + * @blockNamedNodeData: hash table containing data about bitmaps
> + * @actions: filled with arguments for a 'transaction' command
> + * @disabledBitmapsBase: filled with a list of bitmap names which must be disabled
> + *
> + * Prepares data for correctly hanlding bitmaps during the start of a commit

handling

> + * job. The bitmaps in the 'base' image must be disabled, so that the writes
> + * done by the blockjob don't dirty the enabled bitmaps.
> + *
> + * @actions and @disabledBitmapsBase are untouched if no bitmaps need
> + * to be disabled.
> + */
> +int
> +qemuBlockBitmapsHandleCommitStart(virStorageSourcePtr topsrc,
> +                                  virStorageSourcePtr basesrc,
> +                                  virHashTablePtr blockNamedNodeData,
> +                                  virJSONValuePtr *actions,
> +                                  char ***disabledBitmapsBase)
> +{

> +static int
> +qemuBlockBitmapsHandleCommitFinishIterate(void *payload,
> +                                          const void *entryname,
> +                                          void *opaque)
> +{
> +    struct qemuBlockBitmapsHandleCommitData *data = payload;
> +    const char *bitmapname = entryname;
> +    virJSONValuePtr actions = opaque;
> +
> +    if (data->skip)
> +        return 0;
> +
> +    if (data->create) {
> +        if (qemuMonitorTransactionBitmapAdd(actions, data->basenode, bitmapname,
> +                                            data->persistent, !data-> enable,

Spurious space.

> +/**
> + * @topsrc: virStorageSource representing 'top' of the job
> + * @basesrc: virStorageSource representing 'base' of the job
> + * @blockNamedNodeData: hash table containing data about bitmaps
> + * @actions: filled with arguments for a 'transaction' command
> + * @disabledBitmapsBase: bitmap names which were disabled
> + *
> + * Calculates the necessary bitmap merges/additions/enablements to properly
> + * handle commit of images from 'top' into 'base'. The necessary operations
> + * in form of argumets of the 'transaction' command are filled into 'actions'

typo and grammar:
in the form of arguments to

> + * if there is anything to do. Otherwise NULL is returned.
> + */
> +int
> +qemuBlockBitmapsHandleCommitFinish(virStorageSourcePtr topsrc,
> +                                   virStorageSourcePtr basesrc,
> +                                   virHashTablePtr blockNamedNodeData,
> +                                   virJSONValuePtr *actions,
> +                                   char **disabledBitmapsBase)
> +{


> +++ b/src/qemu/qemu_block.h
> @@ -229,6 +229,20 @@ qemuBlockBitmapsHandleBlockcopy(virStorageSourcePtr src,
>                                   bool shallow,
>                                   virJSONValuePtr *actions);
> 
> +int
> +qemuBlockBitmapsHandleCommitStart(virStorageSourcePtr topsrc,
> +                                  virStorageSourcePtr basesrc,
> +                                  virHashTablePtr blockNamedNodeData,
> +                                  virJSONValuePtr *actions,
> +                                  char ***disabledBitmapsBase);
> +
> +int
> +qemuBlockBitmapsHandleCommitFinish(virStorageSourcePtr topsrc,
> +                                   virStorageSourcePtr basesrc,
> +                                   virHashTablePtr blockNamedNodeData,
> +                                   virJSONValuePtr *actions,
> +                                   char **disabledBitmapsBase);
> +
>   int
>   qemuBlockReopenReadWrite(virDomainObjPtr vm,
>                            virStorageSourcePtr src,
> 

Reviewed-by: Eric Blake <eblake at redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org