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From: Alasdair G Kergon <agk@redhat.com>
To: Paul Lawrence <paullawrence@google.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
	Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@redhat.com>,
	linux-doc@vger.kernel.org, kernel-team@android.com,
	Jonathan Corbet <corbet@lwn.net>,
	linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
	dm-devel@redhat.com, Shaohua Li <shli@kernel.org>
Subject: Re: [dm-devel] [RFC] dm-bow working prototype
Date: Thu, 25 Oct 2018 01:01:23 +0100	[thread overview]
Message-ID: <20181025000123.GB22722@agk-dp.fab.redhat.com> (raw)
In-Reply-To: <alpine.LRH.2.02.1810241514310.4080@file01.intranet.prod.int.rdu2.redhat.com>

On Wed, Oct 24, 2018 at 03:24:29PM -0400, Mikulas Patocka wrote:
> What about allocating a big file, using the FIEMAP ioctl to find the 

For reference, dmfilemapd in the lvm2 tree (in daemons/) uses FIEMAP
(in libdm/libdm-stats.c) for monitoring I/O by file.

> If you decide that rollback is no longer needed, you just unload the 
> snapshot target and delete the big file. If you decide that you want to 
> rollback, you can use the snapshot merge functionality (or you can write a 
> userspace utility that does offline merge).
 
There's some old code from Mark McLoughlin for userspace snapshot merging here:
  https://people.gnome.org/~markmc/code/merge-dm-snapshot.c

Alasdair


  reply	other threads:[~2018-10-25  0:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-23 21:23 Paul Lawrence
2018-10-23 22:18 ` Alasdair G Kergon
2018-10-24 18:42   ` Paul Lawrence
2018-10-24 19:24     ` [dm-devel] " Mikulas Patocka
2018-10-25  0:01       ` Alasdair G Kergon [this message]
2018-10-25 10:20       ` Bryn M. Reeves
2018-10-25 17:23       ` Paul Lawrence
2018-10-26 20:03         ` Mikulas Patocka
2018-10-29 16:51           ` Paul Lawrence
2018-11-15 23:15             ` Mikulas Patocka
2018-12-02 10:07               ` Sandeep Patil
2018-10-25 16:30 ` MegaBrutal
2018-10-25 18:13   ` Paul Lawrence
2018-10-25 21:15     ` Wols Lists
2018-10-25 21:43 ` [dm-devel] " Darrick J. Wong

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