[Bug 2025339] Re: FDE image fails to run e2fsck

[Paul Mars]

** Description changed:

  After installation of the FDE image, the system fails to boot due to
  e2fsck failing with:
  
  Jun 21 12:48:19 ubuntu systemd-fsck[268]: /dev/vda2 has unsupported
  feature(s): FEATURE_C12
  
  ----
  
  this means that Jammy fsck fails against mantic created ext4 which is
  not great
  
  Seems this is orphan_file feature / orphan_present
  
  Also need to check if grub2 supports this as it is RO_INCOMPAT feature.
  
  [Fix]
  
  This SRU is disabling 2 features (orphan_file and metadata_csum_seed)
  from ext4 to generate filesystems compatible with older series. Fixes
  come from debian (fixing #1031622, #1030939). This is only disabling the
  feature by default. One can still generate a filesystem with this
- feature by explicitly listing them when invoking mkfs.ext4.
+ feature by explicitly listing them when invoking mkfs.ext4. The decision
+ to disable this feature by default has already been taken for mantic and
+ is not planned to be revised soon as far as I know. So this fix is also
+ useful to implement a common behavior between the 2 series (and
+ following ones).
  
+ This fix is also motivated by the fact that snapd is using mkfs.ext4
+ without any options. The possibility to give options for mkfs.ext4 was
+ removed in snapd at some point for good reasons and it would be more
+ complex to handle a special case only for lunar in snapd than disabling
+ this feature by default in e2fsprogs I think.
  
  [Impact]
  
  See LP: #2028564. Generating a filesystem on lunar with e2fsprogs will
  use the orphan_file feature. This will prevent a jammy (or older) based
  OS from modifying this filesystem (in particular resize it at first
  boot).
  
  [ Test Plan ]
  
  On lunar, generate a filesystem and check the orphan_file feature is
  enabled:
  
  $ dd if=/dev/zero of=test.img bs=100M count=1
  $ mkfs.ext4 test.img
  $ # Then check the orphan_file feature is enabled
  $ dumpe2fs test.img | grep orphan
  
  Move this .img file to a jammy based machine, and try using resize2fs on
  it:
  
  $ resize2fs -d -f -M test.img
  
  resize2fs 1.46.5 (30-Dec-2021)
  resize2fs: Filesystem has unsupported feature(s) (test.img)
  
  [Where problems could occur]
  
  Some users on Lunar may currently rely on this feature to be enabled by
  default. This can still be enabled explicitly when calling mkfs.ext4 but
  the default behavior will be changed.
  
  The orphan_file feature aims at improving performances when dealing with
  deleted files or directories. So if we disable this by default, I think
  it should only impact performances of generated filesystems and probably
  not break anything else.
+ 
+ It should be noted that before lunar, users did not have access to this
+ feature and since mantic it is disabled by default, so I suspect the
+ population expecting this feature to be enabled by default is rather
+ small.

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https://bugs.launchpad.net/bugs/2025339

Title:
  FDE image fails to run e2fsck

Status in e2fsprogs package in Ubuntu:
  Fix Released
Status in e2fsprogs source package in Lunar:
  In Progress
Status in e2fsprogs package in Debian:
  Fix Released

Bug description:
  After installation of the FDE image, the system fails to boot due to
  e2fsck failing with:

  Jun 21 12:48:19 ubuntu systemd-fsck[268]: /dev/vda2 has unsupported
  feature(s): FEATURE_C12

  ----

  this means that Jammy fsck fails against mantic created ext4 which is
  not great

  Seems this is orphan_file feature / orphan_present

  Also need to check if grub2 supports this as it is RO_INCOMPAT
  feature.

  [Fix]

  This SRU is disabling 2 features (orphan_file and metadata_csum_seed)
  from ext4 to generate filesystems compatible with older series. Fixes
  come from debian (fixing #1031622, #1030939). This is only disabling
  the feature by default. One can still generate a filesystem with this
  feature by explicitly listing them when invoking mkfs.ext4. The
  decision to disable this feature by default has already been taken for
  mantic and is not planned to be revised soon as far as I know. So this
  fix is also useful to implement a common behavior between the 2 series
  (and following ones).

  This fix is also motivated by the fact that snapd is using mkfs.ext4
  without any options. The possibility to give options for mkfs.ext4 was
  removed in snapd at some point for good reasons and it would be more
  complex to handle a special case only for lunar in snapd than
  disabling this feature by default in e2fsprogs I think.

  [Impact]

  See LP: #2028564. Generating a filesystem on lunar with e2fsprogs will
  use the orphan_file feature. This will prevent a jammy (or older)
  based OS from modifying this filesystem (in particular resize it at
  first boot).

  [ Test Plan ]

  On lunar, generate a filesystem and check the orphan_file feature is
  enabled:

  $ dd if=/dev/zero of=test.img bs=100M count=1
  $ mkfs.ext4 test.img
  $ # Then check the orphan_file feature is enabled
  $ dumpe2fs test.img | grep orphan

  Move this .img file to a jammy based machine, and try using resize2fs
  on it:

  $ resize2fs -d -f -M test.img

  resize2fs 1.46.5 (30-Dec-2021)
  resize2fs: Filesystem has unsupported feature(s) (test.img)

  [Where problems could occur]

  Some users on Lunar may currently rely on this feature to be enabled
  by default. This can still be enabled explicitly when calling
  mkfs.ext4 but the default behavior will be changed.

  The orphan_file feature aims at improving performances when dealing
  with deleted files or directories. So if we disable this by default, I
  think it should only impact performances of generated filesystems and
  probably not break anything else.

  It should be noted that before lunar, users did not have access to
  this feature and since mantic it is disabled by default, so I suspect
  the population expecting this feature to be enabled by default is
  rather small.

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