From: Paolo Bonzini <pbonzini@redhat.com>
To: Eric Blake <eblake@redhat.com>
Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org,
vsementsov@virtuozzo.com, kwolf@redhat.com
Subject: Re: [Qemu-devel] [PATCH] nbd/server: Honor FUA request on NBD_CMD_TRIM
Date: Thu, 8 Mar 2018 01:50:52 -0500 (EST) [thread overview]
Message-ID: <1651749911.5944222.1520491852256.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <20180307225732.155835-1-eblake@redhat.com>
> The NBD spec states that since trim requests can affect disk contents,
> then they should allow for FUA semantics just like writes for ensuring
> the disk has settled before returning. As bdrv_[co_]pdiscard() does
> not (yet?) support a flags argument, we can't pass FUA down the block
> layer stack, and must therefore emulate it with a flush at the NBD
> layer.
TRIM requests should not need FUA since they're just advisory. On
the other hand, WRITE ZEROES requests need to support FUA.
Paolo
next prev parent reply other threads:[~2018-03-08 6:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-07 22:57 [Qemu-devel] [PATCH] nbd/server: Honor FUA request on NBD_CMD_TRIM Eric Blake
2018-03-08 6:50 ` Paolo Bonzini [this message]
2018-03-08 14:45 ` Eric Blake
2018-03-08 15:22 ` Paolo Bonzini
2018-03-08 16:05 ` Eric Blake
2018-03-12 22:30 ` Eric Blake
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