Comment 5 for bug 1896578

Performing verification for Focal.

I enabled -proposed and installed 5.4.0-55-generic to a i3.8xlarge AWS instance.

From there, I followed the testcase steps:

$ uname -rv
5.4.0-55-generic #61-Ubuntu SMP Mon Nov 9 20:49:56 UTC 2020
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 8G 0 disk
└─xvda1 202:1 0 8G 0 part /
nvme0n1 259:0 0 1.7T 0 disk
nvme1n1 259:1 0 1.7T 0 disk
nvme3n1 259:2 0 1.7T 0 disk
nvme2n1 259:3 0 1.7T 0 disk
$ sudo mdadm --create --verbose /dev/md0 --level=10 --raid-devices=4 /dev/nvme0n1 /dev/nvme1n1 /dev/nvme2n1 /dev/nvme3n1
mdadm: layout defaults to n2
mdadm: layout defaults to n2
mdadm: chunk size defaults to 512K
mdadm: size set to 1855336448K
mdadm: automatically enabling write-intent bitmap on large array
mdadm: Fail create md0 when using /sys/module/md_mod/parameters/new_array
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
$ time sudo mkfs.xfs /dev/md0
log stripe unit (524288 bytes) is too large (maximum is 256KiB)
log stripe unit adjusted to 32KiB
meta-data=/dev/md0 isize=512 agcount=32, agsize=28989568 blks
         = sectsz=512 attr=2, projid32bit=1
         = crc=1 finobt=1, sparse=1, rmapbt=0
         = reflink=1
data = bsize=4096 blocks=927666176, imaxpct=5
         = sunit=128 swidth=256 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=452968, version=2
         = sectsz=512 sunit=8 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0

real 0m5.350s
user 0m0.022s
sys 0m0.179s
$ sudo mkdir /mnt/disk
$ sudo mount /dev/md0 /mnt/disk
$ time sudo fstrim /mnt/disk

real 0m2.944s
user 0m0.006s
sys 0m0.013s

We can see that mkfs.xfs took 5.3 seconds, and fstrim only 3 seconds. This is a significant improvement over the current 11 minutes.

I started up a c5.large instance, and attached 4x EBS drives, which do not support block discard, and went through the testcase steps. Everything worked fine, and the changes have not caused any regressions to disks which do not support block discard.

I also started another i3.8xlarge instance and tested raid0, to check for regressions around the refactoring. raid0 deployed fine, and was as performant as usual.

The 5.4.0-55-generic kernel in -proposed fixes the issue, and I am happy to mark as verified.