Thread (11 messages) 11 messages, 5 authors, 2003-08-26

Re: [BUG] 2.6.0-test4-mm1: NFS+XFS=data corruption

From: Steve Lord <hidden>
Date: 2003-08-25 22:58:35
Also in: lkml

On Mon, 2003-08-25 at 14:45, Andrew Morton wrote:
"Barry K. Nathan" [off-list ref] wrote:
quoted
I'm really short on time right now, so this bug report might be vague,
but it's important enough for me to try:

I have an NFS fileserver (running 2.6.0-test4-mm1) exporting stuff from
three filesystems: ReiserFS, ext3, and XFS. I'm seeing no problems with
my ReiserFS and ext3 filesystems. XFS is a different story.

My client machine is running 2.4.21bkn1 (my own kernel, not released to
the public; the differences from vanilla 2.4.21 are XFS and Win4Lin). 

If I use my client machine to sign RPM packages (rpm --addsign ...),
using rpm-4.2-16mdk, and the packages are on the XFS partition on the
NFS server, about half of the packages are truncated by a couple hundred
bytes afterwards (and GPG sig verification fails on those packages).

It's always the same packages that get truncated by the same amounts of
data. This is 100% reproducible. It doesn't matter whether I compile the
kernel with gcc 2.95.3 or 3.1.1. If I perform the operation on my non-XFS
filesystem the problem doesn't happen. If I run 2.6.0-test4-bk2 instead of
test4-mm1 on the NFS server, the problem goes away. (I have never run
any previous -mm kernels on this server.)

Hmmm... If I sign the packages on the NFS server itself, even with
test4-mm1 on the XFS partition, I can't reproduce the problem.
*However*, that's a different version of RPM (4.0.4).

Is this enough information to help find the cause of the bug? If not,
it might be several days (if I'm unlucky, maybe even a week or two)
before I have time to do anything more...
-mm kernels have O_DIRECT-for-NFS patches in them.  And some versions of
RPM use O_DIRECT.  Whether O_DIRECT makes any difference at the server end
I do not know, but it would be useful if you could repeat the test on stock
2.6.0-test4.

Alternatively, run

	export LD_ASSUME_KERNEL=2.2.5

before running RPM.  I think that should tell RPM to not try O_DIRECT.
I doubt the NFS client is O_DIRECT capable here, I have run some rpm
builds over nfs to 2.6.0-test4 and an xfs filesystem, everything is
behaving so far. I will try mm1 tomorrow.

Do we know if this NFS V3 or V2 by the way?

Steve

-- 

Steve Lord                                      voice: +1-651-683-3511
Principal Engineer, Filesystem Software         email: lord@sgi.com
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