Re: [PATCH] SCSI st: expand ability to write immediate filemarks

[Kai Makisara]

On Thu, 1 Mar 2012, Lee Duncan wrote:

> The st tape driver recently added the MTWEOFI ioctl, which writes
> a tape filemark (EOF), like the MTWEOF ioctl, except that MTWEOFI
> returns immediately. This makes certain applications, like backup
> software, run much more quickly on buffered tape drives.
> 
> Since legacy applications do not know about this new MTWEOFI ioctl,
> this patch adds a new ioctl option that tells the st driver to return
> immediately when writing an EOF (i.e. a filemark). This new flag
> is much like the existing flag that tells the st driver to perform
> writes (and certain other IOs) immediately, but this new flag only
> applies to writing EOFs.
> 
> This new feature is controlled via the MTSETDRVBUFFER ioctl, using
> the newly-defined MT_ST_NOWAIT_EOF flag.
> 
> Use of this new feature is displayed via the sysfs tape "options"
> attribute.
> 
> The st documentation was updated to mention this new flag, as well
> as the problems that can occur from using it.
> 
> Signed-off-by: Lee Duncan <lduncan@xxxxxxxx>
Acked-by: Kai Makisara <kai.makisara@xxxxxxxxxxx>

> ---
>  Documentation/scsi/st.txt |    4 ++++
>  drivers/scsi/st.c         |   21 ++++++++++++++++++---
>  drivers/scsi/st.h         |    1 +
>  include/linux/mtio.h      |    1 +
>  4 files changed, 24 insertions(+), 3 deletions(-)

Thanks,
Kai

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