[Lustre-discuss] WARNING: short read while accessing file >4GB on 32-bit client

Johann Lombardi johann at sun.com
Wed Dec 9 04:46:47 PST 2009

Hi all,

A bug impacting 32-bit lustre clients has been identified in the most recent
1.8 releases. This issue manifests itself as a short read from files larger
than 4GB.

The problem is that, on the read path, the lustre client stores the file size
temporarily in a 32-bit variable (this happens only when a glimpse is
necessary). When an application then tries to read beyond the 4GB offset,
variable overflow occurs, resulting in a truncated read returned to the
application. To be clear, this is a client side issue and the file is not at
all corrupted on disk. 64-bit clients are not impacted by this problem.

This regression was introduced in 1.8.1 and will be resolved in 1.8.2 so also
affects Releases and prior (including 1.8.0) are unaffected.
A patch is available in bug 21506.

Best regards,

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