[BUG] 2.4.21: NFS copy produces I/O errors

[Ole Marggraf]

Hello all.

As it seems (to me), there is some serious problem in the NFS code of
2.4.21 (and also of 2.4.20), causing I/O errors quite immediately.

Symptoms are as follows:

    Setup:

    Machine A, running 2.4.21 with NFSv3 client/server
    Machine B, running 2.4.19 with NFSv3 client/server
    (CONFIG_NFS_FS=y
     CONFIG_NFS_V3=y
     CONFIG_NFSD=y
     CONFIG_NFSD_V3=y
    )

    Both machines run the Kernel Automounter v4 (CONFIG_AUTOFS4_FS=y)

    (this should not matter: both machines are running debian testing,
     both have 3c905B ethernet cards)

We copy a file of ca. 100 MB size.

- logged in on machine A:
    cp /A_dir/file /B_dir: I/O error (after 1056768 bytes are written)

- logged in on machine B:
    cp /A_dir/file /B_dir: ok

No error messages are written to the logfiles (client and server), and the
same problem also occurs if we run 2.4.20 instead of 2.4.21.

If _both_ machines run 2.4.21, we get the same problem, i.e. pulling a
file via NFS to a local disk works, pushing to a remote disk fails.

Since we do not get any error messages in the logs, only the plain
"Input/output error" from cp, tracking down the problem is, from our side,
a bit difficult. The size of the file written until the error occurs could
help, it seems to be constant also for different files.

I am curious that this problem never had been observed before, since it
also seems to exist in 2.4.20. At least I did not find any previous
description in the archives.

If I can be of any further help, providing more information or do some
testing, just contact me. If you have any solution, please also give me a
hint ;-) This problem is a bit annoying...

Best regards,

Ole

-- 
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 Ole Marggraf                     email: [e-mail]
 Sternwarte, Universitaet Bonn           [e-mail]
 Auf dem Huegel 71
 D-53121 Bonn, Germany            WWW:   http://www.astro.uni-bonn.de/~marggraf
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