On Tue, Dec 15 2015 at 9:38pm -0500, Martin K. Petersen <martin.petersen@xxxxxxxxxx> wrote: > >>>>> "Bart" == Bart Van Assche <bart.vanassche@xxxxxxxxxxx> writes: > > Bart> Should the caller of blkdev_issue_discard() implement this or > Bart> should this functionality be added in blkdev_issue_discard() > Bart> itself ? > > I'm very much against dropping information in the ioctl/filesystem > submission path. But I am not against having a helper function of some > sort that DM and target could use to handle heads and tails. > > Right now DM does not handle this and I think it would be worthwhile to > have. Mike, what are your requirements? If the discard doesn't conform to the device's stacked discard limits then yes the head and/or tail will get dropped on the floor. Not sure why DM is being made the focal point on this. Are you thinking specifically about DM-thinp and its discard_granularity? DM thinp doesn't support partial thinp block discards -- so misaligned/partial discards are dropped by DM thinp. There isn't a compelling case for fixing this (by adding a bitset for each thinp block to support finer grained discards) -- at least not that I'm aware of. But I'm missing exactly what it is your helper function would do... and yet you're asking me what my requirements are.. sorry ;) -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
