On Thu, Oct 21, 2021 at 06:58:17PM -0700, Darrick J. Wong wrote:

On Fri, Oct 22, 2021 at 01:37:28AM +0000, Jane Chu wrote:

quoted

On 10/21/2021 4:31 AM, Christoph Hellwig wrote:

quoted

Looking over the series I have serious doubts that overloading the
slow path clear poison operation over the fast path read/write
path is such a great idea.

Why would data recovery after a media error ever be considered a
fast/hot path?

Not sure what you're replying to (the text is from me, the mail you are
repling to is fom Jane), but my point is that the read/write
got path should not be overloaded with data recovery.

A normal read/write to a fsdax file would not pass the
flag, which skips the poison checking with whatever MCE consequences
that has, right?

Exactly!

pwritev2(..., RWF_RECOVER_DATA) should be infrequent enough that
carefully stepping around dax_direct_access only has to be faster than
restoring from backup, I hope?

Yes.  And thus be kept as separate as possible.