Tejun Heo <tj <at> kernel.org> writes: > > On Fri, Nov 04, 2011 at 07:46:52AM +1100, NeilBrown wrote: > > What exactly do you mean by "expose both sizes" ?? > > A new ioctl - BLKGETHPASIZE64 ?? > > > > That might work, but I think it would be good if there were also an ioctl > > BLKHBALOCK which changed BLKGETSIZE64 to match BLKGETHPASIZE64. > > Then some user-space tools could examine the device with a full understanding > > of md, dm, dmraid, partitions, filesystems etc etc and make a reasonably > > informed decision. And then put that decision into effect. > > In kernel, just another size field. Out of kernel, I was thinking > more along the line of a new /sysfs field, but yeah maybe another > ioctl. At this point, I don't really think making unlocking > selectable is a good idea. That has to go through device detach / > attach cycle and what if someone else is already using first half of > the disk? We can try to be sneaky and slip in device size change > underneath it but that just sounds too crazy to me. IMHO, we should > unlock by default and just let everyone know what the size before > unlocking was in case that could be useful. > > Thank you. > Just wanted to pop in and say that thanks to your "intelligent HPA unlock" code you submitted to the kernel, I am completely unable to mount and use an NTFS RAID0. The way it ignores the ignore_hpa=0 parameter causes the fakeraid to fail; since the first disk in the array reports a partition size that goes beyond EOD, the code you submitted goes ahead and unlocks it to native -- not HPA limited -- capacity, with the expected result that it completely trashes the array as far as Linux is concerned. What was the point of the huge debate over locking/unlocking by default and the associated parameters if the kernel is going to simply ignore all that -- and my explicit parameter to NOT unlock past HPA size -- and unlock it anyway (which was determined to be a very very bad idea way back in 2009)? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
