[dm-devel] flood of "dm-X: error: dax access failed" due to 5.9 commit 231609785cbfb

[Mike Snitzer]

On Wed, Sep 02 2020 at 12:46pm -0400,
Coly Li <colyli at suse.de> wrote:

> On 2020/9/3 00:44, Mike Snitzer wrote:
> > On Wed, Sep 02 2020 at 12:40pm -0400,
> > Coly Li <colyli at suse.de> wrote:
> > 
> >> On 2020/9/3 00:04, Mike Snitzer wrote:
> >>> 5.9 commit 231609785cbfb ("dax: print error message by pr_info() in
> >>> __generic_fsdax_supported()") switched from pr_debug() to pr_info().
> >>>
> >>> The justification in the commit header is really inadequate.  If there
> >>> is a problem that you need to drill in on, repeat the testing after
> >>> enabling the dynamic debugging.
> >>>
> >>> Otherwise, now all DM devices that aren't layered on DAX capable devices
> >>> spew really confusing noise to users when they simply activate their
> >>> non-DAX DM devices:
> >>>
> >>> [66567.129798] dm-6: error: dax access failed (-5)
> >>> [66567.134400] dm-6: error: dax access failed (-5)
> >>> [66567.139152] dm-6: error: dax access failed (-5)
> >>> [66567.314546] dm-2: error: dax access failed (-95)
> >>> [66567.319380] dm-2: error: dax access failed (-95)
> >>> [66567.324254] dm-2: error: dax access failed (-95)
> >>> [66567.479025] dm-2: error: dax access failed (-95)
> >>> [66567.483713] dm-2: error: dax access failed (-95)
> >>> [66567.488722] dm-2: error: dax access failed (-95)
> >>> [66567.494061] dm-2: error: dax access failed (-95)
> >>> [66567.498823] dm-2: error: dax access failed (-95)
> >>> [66567.503693] dm-2: error: dax access failed (-95)
> >>>
> >>> commit 231609785cbfb must be reverted.
> >>>
> >>> Please advise, thanks.
> >>
> >> Adrian Huang from Lenovo posted a patch, which titled: dax: do not print
> >> error message for non-persistent memory block device
> >>
> >> It fixes the issue, but no response for now. Maybe we should take this fix.
> > 
> > OK, yes sounds like it.  It was merged and is commit c2affe920b0e066
> > ("dax: do not print error message for non-persistent memory block
> > device")
> 
> Thanks for informing me this patch is merged, I am going to update my
> local one :-)

So the thing is I'm running v5.9-rc3 (which includes this commit) but
I'm still seeing all these warnings when I run the lvm2 testsuite.  The
reason _seems_ to be because the lvm2 testsuite uses brd devices for
test devices.  So there is something about the brd device that shows
commit c2affe920b0e066 isn't enough :(

Mike