From: David Howells <dhowells@redhat.com>
To: Andreas Dilger <adilger@dilger.ca>
Cc: dhowells@redhat.com, Christoph Hellwig <hch@lst.de>,
Qu Wenruo <quwenruo.btrfs@gmx.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
linux-ext4 <linux-ext4@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-btrfs <linux-btrfs@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Problems with determining data presence by examining extents?
Date: Wed, 15 Jan 2020 20:55:02 +0000 [thread overview]
Message-ID: <23762.1579121702@warthog.procyon.org.uk> (raw)
In-Reply-To: <C0F67EC5-7B5D-4179-9F28-95B84D9CC326@dilger.ca>
Andreas Dilger <adilger@dilger.ca> wrote:
> I think what is needed here is an fadvise/ioctl that tells the filesystem
> "don't allocate blocks unless actually written" for that file.
Yeah - and it would probably need to find its way onto disk so that its effect
is persistent and visible to out-of-kernel tools.
It would also have to say that blocks of zeros shouldn't be optimised away.
David
next prev parent reply other threads:[~2020-01-15 20:55 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 16:48 Problems with determining data presence by examining extents? David Howells
2020-01-14 22:49 ` Theodore Y. Ts'o
2020-01-15 3:54 ` Qu Wenruo
2020-01-15 12:46 ` Andreas Dilger
2020-01-15 13:10 ` Qu Wenruo
2020-01-15 13:31 ` Christoph Hellwig
2020-01-15 19:48 ` Andreas Dilger
2020-01-16 10:16 ` Christoph Hellwig
2020-01-15 20:55 ` David Howells [this message]
2020-01-15 22:11 ` Andreas Dilger
2020-01-15 23:09 ` David Howells
2020-01-26 18:19 ` Zygo Blaxell
2020-01-15 14:35 ` David Howells
2020-01-15 14:48 ` Christoph Hellwig
2020-01-15 14:59 ` David Howells
2020-01-16 10:13 ` Christoph Hellwig
2020-01-17 16:43 ` David Howells
2020-01-15 14:20 ` David Howells
2020-01-15 8:38 ` Christoph Hellwig
2020-01-15 13:50 ` David Howells
2020-01-15 14:05 ` David Howells
2020-01-15 14:24 ` Qu Wenruo
2020-01-15 14:50 ` David Howells
2020-01-15 14:15 ` David Howells
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