On Mon, Mar 8, 2021 at 11:31 PM Christoph Hellwig <hch@xxxxxx> wrote: > > On Mon, Mar 08, 2021 at 10:54:22PM -0800, Dan Williams wrote: > > Previous kernels allowed the BLKROSET to override the disk's read-only > > status. With that situation fixed the pmem driver needs to rely on > > revalidate_disk() to clear the disk read-only status after the host > > region has been marked read-write. > > > > Recall that when libnvdimm determines that the persistent memory has > > lost persistence (for example lack of energy to flush from DRAM to FLASH > > on an NVDIMM-N device) it marks the region read-only, but that state can > > be overridden by the user via: > > > > echo 0 > /sys/bus/nd/devices/regionX/read_only > > > > ...to date there is no notification that the region has restored > > persistence, so the user override is the only recovery. > > I've just resent my series to kill of ->revalidate_disk for good, so this > obvious makes me a little unhappy. Given that ->revalidate_disk > only ends up beeing called from the same path that ->open is called, > why can't you just hook this up from the open method? > > Also any reason the sysfs attribute can't just directly propagate the > information to the disk? I should have assumed that revalidate_disk() was on the chopping block. Let me take a look at just propagating from the region update down to all affected disks. There's already a notification path for regions to communicate badblocks, should be straightforward to reuse for read-only updates.
