The current version of the mkfs.xfs man page in RHEL9 (and upstream) contains this caveat: > Note: the filesystem DAX mount option ( -o dax ) is incompatible with reflink-enabled XFS filesystems. To use filesystem DAX with XFS, specify the -m reflink=0 option to mkfs.xfs to disable the reflink feature. This is no longer the case upstream, and with the updates in kernel bug #2192730 it is no longer the case for RHEL9. We need to send a patch upstream to address this, probably mentioning the kernel version which added dax+reflink support, and add a similar patch to RHEL9. Thanks, -Eric
The patch to fix this upstream has been sent to the xfs mailing list, and was reviewed by Darrick. Carlos, if you approve of the change as well, getting it to for-next would be a good next step so that we can backport it to RHEL9.3 fairly soon. Thanks, -Eric
Yes, please!
Back porting: 780e93c5 mkfs.xfs.8: correction on mkfs.xfs manpage since reflink and dax are compatible
Find this info in mkfs.xfs of xfsprogs-5.19.0-3.el9.x86_64. [root@dell-per750-43 xfstests-dev]# rpm -qa xfsprogs xfsprogs-5.19.0-3.el9.x86_64 [root@dell-per750-43 ~]# man mkfs.xfs |grep -A 2 -i dax Note: the filesystem DAX mount option ( -o dax ) is incompatible with reflink-enabled XFS filesystems. To use filesystem DAX with XFS, specify the -m reflink=0 option to mkfs.xfs to disable the reflink feature. -- daxinherit=value If value is set to 1, all inodes created by mkfs.xfs will be created with the DAX flag set. The default is 0. Directories will pass on this flag to newly created regular files and directories. By default, mkfs.xfs will not enable DAX mode. -f Force overwrite when an existing filesystem is detected on the device. By default, mkfs.xfs will not write to the device if it suspects Verify on xfsprogs-5.19.0-4.el9 [root@dell-per750-43 ~]# man mkfs.xfs |grep -A 2 -i dax daxinherit=value If value is set to 1, all inodes created by mkfs.xfs will be created with the DAX flag set. The default is 0. Directories will pass on this flag to newly created regular files and directories. By default, mkfs.xfs will not enable DAX mode. -f Force overwrite when an existing filesystem is detected on the device. By default, mkfs.xfs will not write to the device if it suspects [root@dell-per750-43 ~]# rpm -qa xfsprogs xfsprogs-5.19.0-4.el9.x86_64