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

[Johann Lombardi]

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 1.8.1.1. Releases 1.8.0.1 and prior (including 1.8.0) are unaffected.
A patch is available in bug 21506.

Best regards,
Johann