[PATCH v2 0/3] ext4: Add support for mounted updates to the superblock via an ioctl

[Theodore Ts'o via B4 Relay <devnull+tytso.mit.edu@kernel.org>]

This patch series enables a future version of tune2fs to be able to
modify certain parts of the ext4 superblock without to write to the
block device.

The first patch fixes a potential buffer overrun caused by a
maliciously moified superblock.  The second patch adds support for
32-bit uid and gid's which can have access to the reserved blocks pool.
The last patch adds the ioctl's which will be used by tune2fs.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
Changes in v2:
- fix bugs that were detected using sparse
- remove tune (unsafe) ability to clear certain compat faatures
- add the ability to set the encoding and encoding flags for case folding
- Link to v1: https://lore.kernel.org/r/20250908-tune2fs-v1-0-e3a6929f3355@mit.edu

---
Theodore Ts'o (3):
      ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()
      ext4: add support for 32-bit default reserved uid and gid values
      ext4: implemet new ioctls to set and get superblock parameters

 fs/ext4/ext4.h            |  16 +++-
 fs/ext4/ioctl.c           | 312 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/ext4/super.c           |  25 +++----
 include/uapi/linux/ext4.h |  53 +++++++++++++
 4 files changed, 382 insertions(+), 24 deletions(-)
---
base-commit: b320789d6883cc00ac78ce83bccbfe7ed58afcf0
change-id: 20250830-tune2fs-3376beb72403

Best regards,
-- 
Theodore Ts'o <tytso@mit.edu>