On 6/7/22 19:09, Christoph Hellwig wrote:
On Tue, Jun 07, 2022 at 03:53:35PM +0900, Damien Le Moal wrote:
+ else if (offset < isize)
length = min(length, isize - offset);
So you still report an IOMAP_UNWRITTEN extent for the whole size of
the requst past EOF? Looking at XFS we do return the whole requested
length, but do return it as HOLE. Maybe we need to clarify the behavior
here and document it.
Yes, I checked xfs and saw that. But in zonefs case, since the file blocks are
always preallocated, blocks after the write pointer are indeed UNWRITTEN. I did
check that iomap read processing treats UNWRITTEN and HOLE similarly, that is,
ignore the value of length and stop issuing IOs when either type is seen. But I
may have missed something.
Note that initially I wrote the patch below to fix the problem. But it is very
large and should probably be a cleanup for the next cycle. It separates the
begin op for read and write, which makes things easier to understand.
I much prefer this more extensive fix.
OK. Will resend with this change. It does make the code a lot cleaner.
--
Damien Le Moal
Western Digital Research
