Re: [Qemu-devel] [PATCH v5 03/11] block: add basic backup support to block driver

[Kevin Wolf <kwolf@redhat.com>]

Am 30.05.2013 um 14:34 hat Stefan Hajnoczi geschrieben:
> From: Dietmar Maurer <dietmar@proxmox.com>
> 
> backup_start() creates a block job that copies a point-in-time snapshot
> of a block device to a target block device.
> 
> We call backup_do_cow() for each write during backup. That function
> reads the original data from the block device before it gets
> overwritten.  The data is then written to the target device.
> 
> Currently backup cluster size is hardcoded to 65536 bytes.
> 
> [I made a number of changes to Dietmar's original patch and folded them
> in to make code review easy.  Here is the full list:
> 
>  * Drop BackupDumpFunc interface in favor of a target block device
>  * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes()
>  * Use 0 delay instead of 1us, like other block jobs
>  * Unify creation/start functions into backup_start()
>  * Simplify cleanup, free bitmap in backup_run() instead of cb
>  * function
>  * Use HBitmap to avoid duplicating bitmap code
>  * Use bdrv_getlength() instead of accessing ->total_sectors
>  * directly
>  * Delete the backup.h header file, it is no longer necessary
>  * Move ./backup.c to block/backup.c
>  * Remove #ifdefed out code
>  * Coding style and whitespace cleanups
>  * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks
>  * Keep our own in-flight CowRequest list instead of using block.c
>    tracked requests.  This means a little code duplication but is much
>    simpler than trying to share the tracked requests list and use the
>    backup block size.
>  * Add on_source_error and on_target_error error handling.
> 
> -- stefanha]
> 
> Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> 
> backup size fixes
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

You probably didn't want to have the second part in the final commit
message?

Kevin