Re: [Qemu-devel] [PATCH] Add a disk format named iROW, supporting high-efficiency VM snapshot

[Kevin Wolf]

[ Fixed CC email addresses ]

Am 26.01.2013 08:29, schrieb address@hidden:
> From: Jingsheng Zheng <address@hidden>
> 
> iRow (imporved Redirect-on-Write) is a disk format supporting high-efficiency 
> VM disk snapshot.
> iROW uses bitmap to reduce the amount of metadata, so that both the VM disk 
> snapshot key operations
> performance and the VM disk I/O performance would be enhanced at the same 
> time.
> 
> Signed-off-by : JingshengZheng <address@hidden>
> 
> ---
>  block/Makefile.objs |    1 +
>  block/irow.c        | 2257 
> +++++++++++++++++++++++++++++++++++++++++++++++++++
>  block/irow.h        |  135 +++

Is this meant as an implementation for an existing image format that is
used by other products, or is meant to be new native qemu file format?

If the former, the commit message is lacking pointers to these other
products, as well as a link to the specification.

If the latter, doc/specs/irow.txt is the file that is missing and would
have to be reviewed before we look at any of the code. Additionally, you
would need to have a very strong justification for introducing a new
format because it introduces a maintenance burden for qemu. That
includes data on why (and if you're going for performance, how much)
it's better than existing formats, how much of this is really related to
the format rather than the driver, and why existing drivers can't be
extended to achieve the same.


Codewise, this isn't nearly compliant to the qemu coding style, please
use scripts/checkpatch.pl:

total: 2022 errors, 343 warnings, 2398 lines checked


Please provide at least a spec before we can review this.

Kevin