Robie, I've just updated the description with more information on the user impact (and why we should have this patch), and also the regression potential.
I wasn't completely right in my last comment, sorry - for RAID0/Linear arrays, the output of the array state in "mdadm --detail" may change after the patch _even for healthy arrays_. One example is the "readonly" state: we can write this state to the sysfs "array_state" file for a raid0/linear array, and currently the "mdadm --detail" will keep showing state "clean" (arguably an odd behavior, but it is how the state output works right now). With this patch, the state will show as "readonly".
I think we have two options here:
(a) We can backport the patch as is, hence risking some users running monitoring tools or any kind of scripts parsing "mdadm -detail" output breaking for raid0/linear arrays.
(b) We can introduce a conditional check for Bionic/Disco/Eoan in the "mdadm --detail" output to keep "clean" as the array state unless it's "active" or "broken" (the new state for failed arrays). Then, Focal will get a merge from a more recent version of mdadm with the original patch and diverge from this behavior, being aligned with upstream/other distros.
Basically, the discussion is to "when" introduce the user-visible change, if during the current releases or between releases (Focal being the first to change). There's an hypothetical 3rd alternative that I personally dislike and would avoid, that is introduce such conditional check for all Ubuntu releases from now on and diverge forever from upstream/other distros - I don't see a point in doing this.
Let me know your considerations Robie, and thanks for pointing out valid concerns!
Cheers,
Robie, I've just updated the description with more information on the user impact (and why we should have this patch), and also the regression potential.
I wasn't completely right in my last comment, sorry - for RAID0/Linear arrays, the output of the array state in "mdadm --detail" may change after the patch _even for healthy arrays_. One example is the "readonly" state: we can write this state to the sysfs "array_state" file for a raid0/linear array, and currently the "mdadm --detail" will keep showing state "clean" (arguably an odd behavior, but it is how the state output works right now). With this patch, the state will show as "readonly".
I think we have two options here:
(a) We can backport the patch as is, hence risking some users running monitoring tools or any kind of scripts parsing "mdadm -detail" output breaking for raid0/linear arrays.
(b) We can introduce a conditional check for Bionic/Disco/Eoan in the "mdadm --detail" output to keep "clean" as the array state unless it's "active" or "broken" (the new state for failed arrays). Then, Focal will get a merge from a more recent version of mdadm with the original patch and diverge from this behavior, being aligned with upstream/other distros.
Basically, the discussion is to "when" introduce the user-visible change, if during the current releases or between releases (Focal being the first to change). There's an hypothetical 3rd alternative that I personally dislike and would avoid, that is introduce such conditional check for all Ubuntu releases from now on and diverge forever from upstream/other distros - I don't see a point in doing this.
Let me know your considerations Robie, and thanks for pointing out valid concerns!
Cheers,
Guilherme