From: Chuck Lever <chuck.lever@oracle.com>

Following on from

https://lore.kernel.org/linux-nfs/20251021-zypressen-bazillus-545a44af57fd@brauner/T/#m0ba197d75b7921d994cf284f3cef3a62abb11aaa

I'm attempting to implement enough support in the Linux VFS to
enable file services like NFSD and ksmbd (and user space
equivalents) to provide the actual status of case folding support
in local file systems. The default behavior for local file systems
not explicitly supported in this series is to reflect the usual
POSIX behaviors:

  case-insensitive = false
  case-preserving = true

Changes since RFC:
- Use file_getattr instead of statx
- Postpone exposing Unicode version until later
- Support NTFS and ext4 in addition to FAT
- Support NFSv4 fattr4 in addition to NFSv3 PATHCONF

Chuck Lever (6):
  fs: Add case sensitivity info to file_kattr
  fat: Implement fileattr_get for case sensitivity
  ntfs3: Implement fileattr_get for case sensitivity
  ext4: Report case sensitivity in fileattr_get
  nfsd: Report export case-folding via NFSv3 PATHCONF
  nfsd: Implement NFSv4 FATTR4_CASE_INSENSITIVE and
    FATTR4_CASE_PRESERVING

 fs/ext4/ioctl.c          | 12 ++++++++++++
 fs/fat/fat.h             |  3 +++
 fs/fat/file.c            | 18 ++++++++++++++++++
 fs/fat/namei_msdos.c     |  1 +
 fs/fat/namei_vfat.c      |  1 +
 fs/file_attr.c           | 31 +++++++++++++++++++++++++++++++
 fs/nfsd/nfs3proc.c       | 18 ++++++++++--------
 fs/nfsd/nfs4xdr.c        | 30 ++++++++++++++++++++++++++----
 fs/nfsd/vfs.c            | 25 +++++++++++++++++++++++++
 fs/nfsd/vfs.h            |  2 ++
 fs/ntfs3/file.c          | 27 +++++++++++++++++++++++++++
 fs/ntfs3/inode.c         |  1 +
 fs/ntfs3/namei.c         |  2 ++
 fs/ntfs3/ntfs_fs.h       |  1 +
 include/linux/fileattr.h | 23 +++++++++++++++++++++++
 15 files changed, 183 insertions(+), 12 deletions(-)

-- 
2.52.0

On Thu, Dec 11, 2025 at 10:21:10AM -0500, Chuck Lever wrote:
> - Support NTFS and ext4 in addition to FAT

Still missing at least xfs, hfs, hfsplus and exfat, nfs and cifs.