On 27/05/2020 11:07, Steven Whitehouse wrote:
By default, I can't see any reason why we'd want a block sizes less than
4k. We might want to allow someone to do that for special cases, but
generally the lower block sizes cause issue with larger file sizes, due
to the increased height of the metadata tree. As such we should try and
avoid them, and ignoring all hints of below 4k seems like a sensible plan.
If someone specifically requests a smaller block size on the command
line, then that is another thing, but we should try and protect people
from devices which advertise really small optimal I/O sizes. Really we
should be using that in combination with the alignment information when
laying out the larger structures on disk, and not using it for selecting
the block size - assuming again that these sizes have been set by the
device to something sensible in the first place,
OK, that makes sense to me. I'll redo the patch to only choose a block
size <4K if it's specified on the command line.
Andy
