Re: [PATCH v4] Add test 249: Check filesystem FITRIM implementation

From: Alex Elder <aelder@sgi.com>
To: Lukas Czerner <lczerner@redhat.com>
Cc: hch@infradead.org, esandeen@redhat.com, xfs@oss.sgi.com
Subject: Re: [PATCH v4] Add test 249: Check filesystem FITRIM implementation
Date: Mon, 21 Feb 2011 09:42:08 -0600	[thread overview]
Message-ID: <1298302928.7713.4.camel@doink> (raw)
In-Reply-To: <alpine.LFD.2.00.1102211352330.8461@dhcp-27-109.brq.redhat.com>

On Mon, 2011-02-21 at 14:37 +0100, Lukas Czerner wrote:
> On Wed, 9 Feb 2011, Lukas Czerner wrote:
> 
> > FITRIM ioctl  is used on a mounted filesystem to discard (or "trim")
> > blocks which are not in use by the filesystem.  This is useful for
> > solid-state drives (SSDs) and thinly-provi-sioned storage. This test
> > helps to verify filesystem FITRIM implementation to assure that it
> > does not corrupts data.
> > 
> > This test creates checksums of all files in xfstests directory and
> > run several processes which clear its working directory on SCRATCH_MNT,
> > then copy everything from xfstests into its working directory, create
> > list of files in working directory and its checksums and compare it with the
> > original list of checksums. Every process works in the loop so it repeat
> > remove->copy->check, while fstrim tool is running simultaneously.
> > 
> > Fstrim is just a helper tool which uses FITRIM ioctl to actually do the
> > filesystem discard.
> > 
> > I found this very useful because when the FITRIM is really buggy (thus
> > data-destroying) the 249 test will notice, because checksums will most
> > likely change.
> 
> Hello,
> 
> I know that there has been some problems with this in the past, but I
> would be REALLY pleased if it should just go in already. The test number
> probably needs to be updated, though.

Lukas, I will commit this for you.  Either later today or
tomorrow.  It was ready to go last week but I was preoccupied
with getting my metadump patch series wrapped up.  I'm done with
that now (waiting for a review).

I will update the test number to suit the latest code before I
commit it.  Thank you for your work on it, and for your patience.
I'm sorry you've had to wait so long for this.

					-Alex

> The thing is, that more and more batched discard implementations are
> popping up and I do not even know if, or how, they are testing it. And
> I just can not keep pointing them to the patch in the mailing list.
> 
> I know that that is probably mainly my fault, because of the
> imperfections of the test, but *I hope* it should be all sorted out now
> (except of test number obviously!). Could you please consider merging it
> in ?
> 
> Thanks!
> -Lukas

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