From: Paolo Bonzini <pbonzini@redhat.com>
To: "Richard W.M. Jones" <rjones@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] fstrim & upstream kernel not working
Date: Fri, 14 Mar 2014 13:47:59 +0100 [thread overview]
Message-ID: <5322FA7F.3030802@redhat.com> (raw)
In-Reply-To: <20140314124216.GQ1346@redhat.com>
Il 14/03/2014 13:42, Richard W.M. Jones ha scritto:
> I worked around this in any case by rearranging the test [2]:
>
> Doing:
>
> rm /a_big_file
> fstrim /
> sync
> umount /
> [shut down qemu]
>
> would only trim 64 KB on the host.
>
> Doing:
>
> rm /a_big_file
> umount / # added
> mount -o nodiscard /dev/sda / # added
> fstrim /
> sync
> umount /
> [shut down qemu]
>
> would trim the expected amount (around 10 MB).
>
> I've no idea why this is (looks like an ext4/kernel bug to me), but in
> any case the tests now use the second method[2].
Could be a race condition (something going on in the background between
rm and fstrim). Try syncing before fstrim, not after. In fact the sync
before umount should not be necessary.
Paolo
next prev parent reply other threads:[~2014-03-14 12:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-13 21:49 [Qemu-devel] fstrim & upstream kernel not working Richard W.M. Jones
2014-03-14 12:30 ` Paolo Bonzini
2014-03-14 12:42 ` Richard W.M. Jones
2014-03-14 12:47 ` Paolo Bonzini [this message]
2014-03-14 13:24 ` Richard W.M. Jones
2014-03-14 13:28 ` Paolo Bonzini
2014-03-14 13:34 ` Richard W.M. Jones
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