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Re: [Qemu-devel] [PATCH 14/20] nbd: Support BDRV_REQ_FUA
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH 14/20] nbd: Support BDRV_REQ_FUA |
Date: |
Sat, 26 Mar 2016 21:46:56 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 |
On 18.03.2016 19:21, Kevin Wolf wrote:
> The NBD server already used to send a FUA flag when the writethrough
> mode was set. This code was a remnant from the times where protocol
> drivers actually had to implement writethrough modes. Since nowadays the
> block layer sends flushes in writethrough mode and non-root nodes are
> always writeback, this was mostly dead code - only mostly because if NBD
> was configured to be used without a format, we sent _both_ FUA and an
> explicit flush afterwards, which makes the code not technically dead,
> but useless overhead.
>
> This patch changes the code so that the block layer's FUA flag is
> recognised and translated into a NBD FUA flag. The additional flush is
> avoided now.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> block/nbd-client.c | 13 +++++++------
> block/nbd-client.h | 2 +-
> block/nbd.c | 26 +++++++++++++++++++++-----
> 3 files changed, 29 insertions(+), 12 deletions(-)
Looks good, but I have the same issue as with patch 13.
Max
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- Re: [Qemu-devel] [PATCH 15/20] raw: Support BDRV_REQ_FUA, (continued)
- [Qemu-devel] [PATCH 12/20] block: Introduce bdrv_co_writev_flags(), Kevin Wolf, 2016/03/18
- [Qemu-devel] [PATCH 13/20] iscsi: Support BDRV_REQ_FUA, Kevin Wolf, 2016/03/18
- [Qemu-devel] [PATCH 11/20] block/qapi: Use blk_enable_write_cache(), Kevin Wolf, 2016/03/18
- [Qemu-devel] [PATCH 14/20] nbd: Support BDRV_REQ_FUA, Kevin Wolf, 2016/03/18
- Re: [Qemu-devel] [PATCH 14/20] nbd: Support BDRV_REQ_FUA,
Max Reitz <=
- [Qemu-devel] [PATCH 18/20] block: Remove bdrv_parse_cache_flags(), Kevin Wolf, 2016/03/18
- [Qemu-devel] [PATCH 17/20] qemu-io: Use bdrv_parse_cache_mode() in reopen_f(), Kevin Wolf, 2016/03/18
- [Qemu-devel] [PATCH 20/20] block: Remove bdrv_(set_)enable_write_cache(), Kevin Wolf, 2016/03/18
- [Qemu-devel] [PATCH 19/20] block: Remove BDRV_O_CACHE_WB, Kevin Wolf, 2016/03/18