Comment 0 for bug 1846486

== SRU Justifucation Eoan ==

Now that 5.4 contains a fix to the bootup regression due to the lack of entropy at bootable we should apply this fix and also revert the revert of commit "Revert "ext4: make __ext4_get_inode_loc plug"".

== Fix ==

So, to clarify, apply the two upstream 5.4-rc commits:

commit 50ee7529ec4500c88f8664560770a7a1b65db72b
Author: Linus Torvalds <email address hidden>
Date: Sat Sep 28 16:53:52 2019 -0700

    random: try to actively add entropy rather than passively wait for it

commit 02f03c4206c1b2a7451d3b3546f86c9c783eac13
Author: Linus Torvalds <email address hidden>
Date: Sun Sep 29 17:59:23 2019 -0700

    Revert "Revert "ext4: make __ext4_get_inode_loc plug""

I've benchmarked the Eoan kernel with these two patches and found the following speed improvements:

git grep of the kernel: 0.14%
building fwts: 0.40%
build stress-ng 0.45%
tar up kernel source: 7.6%
boot time of eoan cloud image: 10.5%

So I think this justifies the speed improvements.

== Regression potential ==

minor change to ext4, which has been regression tested, so risk here is small. The entropy change will alter the random number generation, but I believe this does not change the cryptographical security of the random numbers being generated, so think this change is not security risk.

originally the ext4 change caused boot time user space regressions because of the entropy change of this fix, but the random fix addresses this, so I believe this risk is now zero.