Any possibility of getting SILI support working to support short reads?

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Any possibility of getting SILI support working to support short reads?

Tim Jones
When dealing with tapes from different sources, we quite often end up with tapes that have been written with varying block sizes.  As it stands, mhvtl returns a read failure rather a short read.  For example,

dd if=/dev/nst0 bs=4096 count=1

With no short read support, we get a generic read error.  However, with SILI support enabled:

mt -f /dev/nst0 stopt scsi2log sili

We get the requested 4K of data.

From Kai's documentation on mt-st:

              sili           Set  the   SILI  bit  when  reading  in  variable
                             block mode. This  may  speed  up  reading  blocks
                             shorter than the read byte count. Set this option
                             only if you know that the drive supports SILI and
                             the  HBA  reliably returns transfer residual byte
                             counts. Requires kernel version >= 2.6.26.

This works very well with live drives, but the failure with mhvtl makes testing variable block tapes difficult when emulating multiple tape sources.