Re: [Qemu-devel] [PATCH v9 02/13] block/backup: split shareable copying part from backup_do_cow

[Max Reitz <mreitz@redhat.com>]

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On 26.08.19 18:13, Vladimir Sementsov-Ogievskiy wrote:
> Split copying logic which will be shared with backup-top filter.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/backup.c | 47 ++++++++++++++++++++++++++++++++---------------
>  1 file changed, 32 insertions(+), 15 deletions(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index 33b144305f..13a1d80157 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -248,26 +248,18 @@ static int64_t backup_bitmap_reset_unallocated(BackupBlockJob *s,
>      return ret;
>  }
>  
> -static int coroutine_fn backup_do_cow(BackupBlockJob *job,
> -                                      int64_t offset, uint64_t bytes,
> -                                      bool *error_is_read,
> -                                      bool is_write_notifier)
> +static int coroutine_fn backup_do_copy(BackupBlockJob *job,
> +                                       int64_t offset, uint64_t bytes,
> +                                       bool *error_is_read,
> +                                       bool is_write_notifier)
>  {
> -    CowRequest cow_request;
>      int ret = 0;
> -    int64_t start, end; /* bytes */
> +    int64_t start = offset, end = bytes + offset; /* bytes */

Maybe just rename the “offset” parameter to “start”, replace the “bytes”
parameter by an “end” parameter, and drop this line?

Max

>      void *bounce_buffer = NULL;
>      int64_t status_bytes;
>  
> -    qemu_co_rwlock_rdlock(&job->flush_rwlock);
> -
> -    start = QEMU_ALIGN_DOWN(offset, job->cluster_size);
> -    end = QEMU_ALIGN_UP(bytes + offset, job->cluster_size);
> -
> -    trace_backup_do_cow_enter(job, start, offset, bytes);
> -
> -    wait_for_overlapping_requests(job, start, end);
> -    cow_request_begin(&cow_request, job, start, end);
> +    assert(QEMU_IS_ALIGNED(start, job->cluster_size));
> +    assert(QEMU_IS_ALIGNED(end, job->cluster_size));
>  
>      while (start < end) {
>          int64_t dirty_end;


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