On Sat, Aug 26, 2023 at 06:25:58PM -0700, Joshua Hudson wrote: > I am presuming you mean "Are you sure this not a hardware issue?" > > I am sure it is not, for two reasons. > > 1) If it were a hardware issue I would still expect the two device > nodes (whole disk and partition) to report the *same* data. > > 2) I have since developed a workaround involving BLKFLSDEV. The > workaround is really ugly. Whole disk and all partitions have page caches of their own. There is no coherency between those; write through one, then read through another and you are not guaranteed that read won't see the stale cached data. Doctor, it hurts when I do it... Incidentally, read from device/write to the place you've read via file/read from device again also has no coherency warranties, for exact same reason. IOW, not a bug.
