linux-ext4 - Re: Fast symlinks stored slow

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Message-ID: <20170713171335.GT31999@redhat.com>
Date:   Thu, 13 Jul 2017 18:13:35 +0100
From:   "Richard W.M. Jones" <rjones@...hat.com>
To:     Theodore Ts'o <tytso@....edu>
Cc:     linux-ext4@...r.kernel.org, Tahsin Erdogan <tahsin@...gle.com>
Subject: Re: Fast symlinks stored slow

On Thu, Jul 13, 2017 at 12:49:59PM -0400, Theodore Ts'o wrote:
> On Thu, Jul 13, 2017 at 09:02:13AM +0100, Richard W.M. Jones wrote:
> > 
> > From my point of view it's not too much trouble to recreate these
> > filesystems, and we've already proposed a fix for supermin so it
> > creates symlinks properly[1].
> 
> My concern is that people using libguestfs, et.al., on Fedura XX and
> then try to decide to upgrade to the 4.13 kernel.  So it sounds like
> the exposure could be pretty large.  Am I wrong?

In this case we're using libext2fs to build an appliance filesystem,
used to boot a small Linux system which is then run under qemu by
libguestfs.  This appliance is completely rebuilt automatically under
many circumstances, for example a host package upgrade (eg. upgrading
the kernel), so it's not a long-lived filesystem that would cause a
problem.  Rebuilding only takes a few seconds.

The process is described in more detail here:
http://libguestfs.org/supermin.1.html#SUPERMIN-APPLIANCES

>From our point of view the only issue are some prebuilt appliances
which we have provided to other distributions that cannot / don't want
to use supermin (http://download.libguestfs.org/binaries/appliance/)
and at some point I'm going to have to rebuild these using the fixed
supermin.

Rich.

-- 
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