[v3.7 Regression] [SCSI] sd: Implement support for WRITE SAME

Mike Snitzer snitzer at redhat.com
Wed Dec 19 19:58:01 UTC 2012

On Wed, Dec 19 2012 at 11:58am -0500,
Martin K. Petersen <martin.petersen at oracle.com> wrote:

> >>>>> "Joseph" == Joseph Salisbury <joseph.salisbury at canonical.com> writes:
> Joseph> I captured the netconsole output from boot until I reproduced
> Joseph> the bug. The RIP points to kcryptd_crypt_write_io_submit() in
> Joseph> ~/drivers/md/dm-crypt.c.  The output can be seen at:
> I'm thinking that dm-crypt should probably set max_write_same_sectors to
> 0. It doesn't really make much sense for a crypto driver to pass that
> command through.
> Mike, do you want to look into this?

Milan (cc'd) is more well-versed with dm-crypt.  Though we likely need
to audit DM relative to WRITE SAME too (will do once I understand what
added safety/constraints are needed).

But do we know mount to somwhow be issuing WRITE SAME requests?  Martin,
why is it you weren't able to reproduce (I haven't attempted yet)?

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