From: Kevin Wolf <kwolf@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
qemu-block@nongnu.org, qemu-devel@nongnu.org,
Stefan Hajnoczi <stefanha@redhat.com>,
Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH v2 0/3] block: Warn about usage of growing formats over non-growable protocols
Date: Thu, 7 May 2015 15:20:56 +0200 [thread overview]
Message-ID: <20150507132056.GC4571@noname.redhat.com> (raw)
In-Reply-To: <554B5ED3.4030405@redhat.com>
Am 07.05.2015 um 14:47 hat Paolo Bonzini geschrieben:
>
>
> On 07/05/2015 14:29, Kevin Wolf wrote:
> > > No, it shouldn't indeed.
> > >
> > > Could alloc_clusters_noref do bdrv_truncate and return ENOSPC if it
> > > fails? That's how for example qcow and vhdx work. vdi has the same
> > > problem.
> >
> > If you want NBD to return -ENOSPC for writes after EOF, change the
> > nbd block driver to do just that. There's no reason to add additional
> > overhead to qcow2 (even over raw-posix) for that.
>
> Does ENOSPC over LVM (dm-linear) work at all, and who generates the
> ENOSPC there?
The LVM use case is what oVirt uses, so I'm pretty sure that it works.
I'm now sure who generates the ENOSPC, but it's not qemu anyway. If I
had to guess, I'd say that the kernel block layer might just forbid
writing after EOF for any block device.
Kevin
next prev parent reply other threads:[~2015-05-07 13:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-19 19:03 [Qemu-devel] [PATCH v2 0/3] block: Warn about usage of growing formats over non-growable protocols Max Reitz
2015-03-19 19:03 ` [Qemu-devel] [PATCH v2 1/3] iotests: Make nested read in 072 and 089 read-only Max Reitz
2015-03-19 19:23 ` Eric Blake
2015-03-19 19:03 ` [Qemu-devel] [PATCH v2 2/3] block: Introduce BDS.growing Max Reitz
2015-03-19 20:11 ` Eric Blake
2015-03-19 19:03 ` [Qemu-devel] [PATCH v2 3/3] block: Introduce BlockDriver.requires_growing_file Max Reitz
2015-03-19 20:18 ` Eric Blake
2015-05-05 9:46 ` [Qemu-devel] [PATCH v2 0/3] block: Warn about usage of growing formats over non-growable protocols Stefan Hajnoczi
2015-05-06 13:04 ` Max Reitz
2015-05-06 15:30 ` Paolo Bonzini
2015-05-06 16:12 ` [Qemu-devel] [Qemu-block] " Max Reitz
2015-05-06 16:20 ` Paolo Bonzini
2015-05-06 16:37 ` Max Reitz
2015-05-06 16:47 ` Paolo Bonzini
2015-05-06 17:23 ` Max Reitz
2015-05-07 12:20 ` Paolo Bonzini
2015-05-07 12:29 ` Kevin Wolf
2015-05-07 12:47 ` Paolo Bonzini
2015-05-07 13:20 ` Kevin Wolf [this message]
2015-05-07 13:55 ` Paolo Bonzini
2015-05-07 14:07 ` Kevin Wolf
2015-05-07 14:16 ` Paolo Bonzini
2015-05-07 14:34 ` Kevin Wolf
2015-05-07 14:50 ` Paolo Bonzini
2015-05-08 10:08 ` Kevin Wolf
2015-05-08 10:16 ` Paolo Bonzini
2015-05-08 10:34 ` Kevin Wolf
2015-05-08 11:00 ` Paolo Bonzini
2015-05-08 12:58 ` Max Reitz
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