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

[Coly Li]

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.

Thanks.

Coly Li