[Drbd-dev] [PATCH 22/25] block: stop using discards for zeroing

Martin K. Petersen martin.petersen at oracle.com
Wed Apr 5 13:55:39 CEST 2017

Christoph Hellwig <hch at lst.de> writes:

> Now that we have REQ_OP_WRITE_ZEROES implemented for all devices that
> support efficient zeroing of devices we can remove the call to

s/of devices/

> blkdev_issue_discard.  This means we only have two ways of zeroing
> left and can simply the code.


> + *  Note that this function may fail with -EOPNOTSUPP if the driver supports
> + *  efficient zeroing operation, but the device capabilities can only be
> + *  discovered by trial and error.  In this case the caller should call the
> + *  function again, and it will use the fallback path.


"Note that this function may fail with -EOPNOTSUPP if the driver signals
zeroing offload support but the device fails to process the command (for
some devices there is no non-destructive way to verify whether this
operation is actually supported). If -EOPNOTSUPP is returned, the caller
should retry the blkdev_issue_zeroout() and the fallback path will be

Otherwise OK.

Reviewed-by: Martin K. Petersen <martin.petersen at oracle.com>

Martin K. Petersen	Oracle Linux Engineering

More information about the drbd-dev mailing list