On Fri, Nov 07, 2014 at 12:08:14AM -0500, Martin K. Petersen wrote: > blkdev_issue_discard() will zero a given block range on disk. This is > done by way of either WRITE SAME or regular WRITE. I.e. the blocks on > disk will be written and thus provisioned. > > There are use cases where the desired behavior is to zero the blocks but > unprovision them if possible. The blocks must deterministically contain > zeroes when they are subsequently read back. > > This patch introduces a blkdev_issue_zeroout_discard() call that > provides this functionality. If a block device guarantees > discard_zeroes_data the new function will use discard to clear the block > range. If the device does not support discard_zeroes_data or if the > discard request fails we will fall back to blkdev_issue_zeroout() to > ensure predictable results. I'm not a fan of adding another function here and would prefer a flag, but it looks correct, so: Reviewed-by: Christoph Hellwig <hch@xxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
