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Re: [PATCH v11 04/14] block/backup: introduce BlockCopyState
From: |
Max Reitz |
Subject: |
Re: [PATCH v11 04/14] block/backup: introduce BlockCopyState |
Date: |
Fri, 20 Sep 2019 14:46:38 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 |
On 13.09.19 20:25, Vladimir Sementsov-Ogievskiy wrote:
> 10.09.2019 13:23, Vladimir Sementsov-Ogievskiy wrote:
>> Split copying code part from backup to "block-copy", including separate
>> state structure and function renaming. This is needed to share it with
>> backup-top filter driver in further commits.
>>
>> Notes:
>>
>> 1. As BlockCopyState keeps own BlockBackend objects, remaining
>> job->common.blk users only use it to get bs by blk_bs() call, so clear
>> job->commen.blk permissions set in block_job_create and add
>> job->source_bs to be used instead of blk_bs(job->common.blk), to keep
>> it more clear which bs we use when introduce backup-top filter in
>> further commit.
>>
>> 2. Rename s/initializing_bitmap/skip_unallocated/ to sound a bit better
>> as interface to BlockCopyState
>>
>> 3. Split is not very clean: there left some duplicated fields, backup
>> code uses some BlockCopyState fields directly, let's postpone it for
>> further improvements and keep this comment simpler for review.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>> ---
>
>
> [..]
>
>> +
>> +static BlockCopyState *block_copy_state_new(
>> + BlockDriverState *source, BlockDriverState *target,
>> + int64_t cluster_size, BdrvRequestFlags write_flags,
>> + ProgressBytesCallbackFunc progress_bytes_callback,
>> + ProgressResetCallbackFunc progress_reset_callback,
>> + void *progress_opaque, Error **errp)
>> +{
>> + BlockCopyState *s;
>> + int ret;
>> + uint64_t no_resize = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE |
>> + BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD;
>> + BdrvDirtyBitmap *copy_bitmap;
>> +
>> + copy_bitmap = bdrv_create_dirty_bitmap(source, cluster_size, NULL,
>> errp);
>> + if (!copy_bitmap) {
>> + return NULL;
>> + }
>> + bdrv_disable_dirty_bitmap(copy_bitmap);
>> +
>> + s = g_new(BlockCopyState, 1);
>> + *s = (BlockCopyState) {
>> + .source = blk_new(bdrv_get_aio_context(source),
>> + BLK_PERM_CONSISTENT_READ, no_resize),
>> + .target = blk_new(bdrv_get_aio_context(target),
>> + BLK_PERM_WRITE, no_resize),
>> + .copy_bitmap = copy_bitmap,
>> + .cluster_size = cluster_size,
>> + .len = bdrv_dirty_bitmap_size(copy_bitmap),
>> + .write_flags = write_flags,
>> + .use_copy_range = !(write_flags & BDRV_REQ_WRITE_COMPRESSED),
>> + .progress_bytes_callback = progress_bytes_callback,
>> + .progress_reset_callback = progress_reset_callback,
>> + .progress_opaque = progress_opaque,
>> + };
>> +
>> + s->copy_range_size = QEMU_ALIGN_UP(MIN(blk_get_max_transfer(s->source),
>> + blk_get_max_transfer(s->target)),
>> + s->cluster_size);
>
> preexistent, but it obviously should be QEMU_ALIGN_DOWN. I can resend with a
> separate
> fix, it may be fixed while queuing (if resend is not needed for other
> reasons) or
> I'll send a follow-up fix later, whichever you prefer.
Hm, true. But then we’ll also need to handle the (unlikely, admittedly)
case where max_transfer < cluster_size so this would then return 0 (by
setting use_copy_range = false). So how about this:
> diff --git a/block/backup.c b/block/backup.c
> index e5bcfe7177..ba4a37dbb5 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -182,9 +182,13 @@ static BlockCopyState *block_copy_state_new(
> .progress_opaque = progress_opaque,
> };
>
> - s->copy_range_size = QEMU_ALIGN_UP(MIN(blk_get_max_transfer(s->source),
> - blk_get_max_transfer(s->target)),
> - s->cluster_size);
> + s->copy_range_size = QEMU_ALIGN_DOWN(MIN(blk_get_max_transfer(s->source),
> +
> blk_get_max_transfer(s->target)),
> + s->cluster_size);
> + if (s->copy_range_size == 0) {
> + /* max_transfer < cluster_size */
> + s->use_copy_range = false;
> + }
>
> /*
> * We just allow aio context change on our block backends. block_copy()
> user
Max
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- [Qemu-block] [PATCH v11 02/14] block/backup: split shareable copying part from backup_do_cow, (continued)
- [Qemu-block] [PATCH v11 02/14] block/backup: split shareable copying part from backup_do_cow, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 06/14] block: move block_copy from block/backup.c to separate file, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 07/14] block: teach bdrv_debug_breakpoint skip filters with backing, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 12/14] block: add lock/unlock range functions, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 01/14] block/backup: fix backup_cow_with_offload for last cluster, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 05/14] block/backup: fix block-comment style, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 08/14] iotests: prepare 124 and 257 bitmap querying for backup-top filter, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 13/14] block: introduce backup-top filter driver, Vladimir Sementsov-Ogievskiy, 2019/09/10
- [Qemu-block] [PATCH v11 04/14] block/backup: introduce BlockCopyState, Vladimir Sementsov-Ogievskiy, 2019/09/10
[Qemu-block] [PATCH v11 10/14] iotests: 257: drop device_add, Vladimir Sementsov-Ogievskiy, 2019/09/10
[Qemu-block] [PATCH v11 14/14] block/backup: use backup-top instead of write notifiers, Vladimir Sementsov-Ogievskiy, 2019/09/10
Re: [Qemu-block] [PATCH v11 00/14] backup-top filter driver for backup, Vladimir Sementsov-Ogievskiy, 2019/09/13