The reiser4 file system patches currently available for Linux kernel 5.10 (as of February 20, 2021) have not been updated to address the 'historic ditching [of] defunct addressing artefact... called set_fs()'. Although the patch series introducing that change in the then still upcoming Linux kernel 5.10 date back from circa August 2020: remove the last set_fs() in common code, and remove it for x86 and powerpc, I can only speculate the reiser4 developer did not anticipate the disruptive effect it was going to have on his work -- as he released reiser4 patches for both stable Software Framework Release Number (SFRN) 4.0.2 and unstable SFRN 5.1.3, aka 'reiser5', for the kernel 5.10. Notwithstanding, I find it odd that I had not read of any bug reports as to the suitability of reiser4 to the Linux 5.10 kernel. But then I created a set of reiser4 -patched Linux 5.10.1 RC kernels for Metztli Reiser4 / Reiser5 d-i installers: None of them worked! This post represents, thus, an overview of the regression procedure to have reiser4 file system re-enabled in the Linux 5.10 kernel series... Continue reading Reiser4 and Linux version Macuilli.Matlactli, i.e., 5.10 at Metztli IT Tonalamatl