From: Kevin Wolf <kwolf@redhat.com>
To: "Richard W.M. Jones" <rjones@redhat.com>
Cc: Hu Tao <hutao@cn.fujitsu.com>, Max Reitz <mreitz@redhat.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>,
Yasunori Goto <y-goto@jp.fujitsu.com>
Subject: Re: [Qemu-devel] [PATCH v12 0/6] qcow2, raw: add preallocation=full and preallocation=falloc
Date: Fri, 22 Aug 2014 15:13:31 +0200 [thread overview]
Message-ID: <20140822131331.GN32377@noname.redhat.com> (raw)
In-Reply-To: <20140822122556.GJ14001@redhat.com>
Am 22.08.2014 um 14:25 hat Richard W.M. Jones geschrieben:
>
> On Mon, Jul 28, 2014 at 04:48:46PM +0800, Hu Tao wrote:
> > ping...
> >
> > All the 6 patches have reviewed-by now.
> >
> > On Fri, Jul 11, 2014 at 02:09:57PM +0800, Hu Tao wrote:
> > > This series adds two preallocation mode to qcow2 and raw:
> > >
> > > Option preallocation=full preallocates disk space for image by writing
> > > zeros to disk, this ensures disk space in any cases.
> > >
> > > Option preallocation=falloc preallocates disk space by calling
> > > posix_fallocate(). This is faster than preallocation=full.
>
> Sorry if this was discussed before, but why would anyone use
> preallocation=full if preallocation=falloc was possible?
>
> Shouldn't preallocation=full simply use posix_fallocate if it's
> available, and fall back to writing zeroes if not?
posix_fallocate() is basically metadata preallocation on the file
system level. If any lower levels involve allocations as well, does
posix_fallocate() allocate them there?
Kevin
next prev parent reply other threads:[~2014-08-22 13:13 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-11 6:09 [Qemu-devel] [PATCH v12 0/6] qcow2, raw: add preallocation=full and preallocation=falloc Hu Tao
2014-07-11 6:09 ` [Qemu-devel] [PATCH v12 1/6] block: round up file size to nearest sector Hu Tao
2014-08-22 10:55 ` Kevin Wolf
2014-08-25 1:11 ` Hu Tao
2014-07-11 6:09 ` [Qemu-devel] [PATCH v12 2/6] raw, qcow2: don't convert file size to sector size Hu Tao
2014-07-11 6:10 ` [Qemu-devel] [PATCH v12 3/6] rename parse_enum_option to qapi_enum_parse and make it public Hu Tao
2014-07-11 6:10 ` [Qemu-devel] [PATCH v12 4/6] qapi: introduce PreallocMode and a new PreallocMode full Hu Tao
2014-08-22 10:57 ` Kevin Wolf
2014-08-25 1:12 ` Hu Tao
2014-07-11 6:10 ` [Qemu-devel] [PATCH v12 5/6] raw-posix: Add falloc and full preallocation option Hu Tao
2014-08-22 10:58 ` Kevin Wolf
2014-08-25 1:18 ` Hu Tao
2014-07-11 6:10 ` [Qemu-devel] [PATCH v12 6/6] qcow2: " Hu Tao
2014-07-11 21:07 ` Max Reitz
2014-08-22 11:00 ` Kevin Wolf
2014-08-25 1:36 ` Hu Tao
2014-07-28 8:48 ` [Qemu-devel] [PATCH v12 0/6] qcow2, raw: add preallocation=full and preallocation=falloc Hu Tao
2014-08-22 10:54 ` Kevin Wolf
2014-08-25 1:35 ` Hu Tao
2014-08-26 10:44 ` Stefan Hajnoczi
2014-08-28 5:04 ` Hu Tao
2014-08-22 12:25 ` Richard W.M. Jones
2014-08-22 12:36 ` Daniel P. Berrange
2014-08-22 13:13 ` Kevin Wolf [this message]
2014-08-22 13:26 ` Richard W.M. Jones
2014-08-22 14:20 ` Daniel P. Berrange
2014-08-22 15:22 ` Kevin Wolf
2014-08-22 15:34 ` Richard W.M. Jones
2014-08-22 15:39 ` Richard W.M. Jones
2014-08-22 15:53 ` Kevin Wolf
2014-08-22 16:00 ` Richard W.M. Jones
2014-08-25 5:18 ` Hu Tao
2014-08-25 10:31 ` Richard W.M. Jones
2014-08-25 13:44 ` Richard W.M. Jones
2014-08-26 5:27 ` Hu Tao
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