On Thu, Jan 22, 2026, at 7:26 PM, Darrick J. Wong wrote:

On Thu, Jan 22, 2026 at 11:02:56AM -0500, Chuck Lever wrote:

quoted

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

Enable upper layers such as NFSD to retrieve case sensitivity
information from file systems by adding FS_XFLAG_CASEFOLD and
FS_XFLAG_CASENONPRESERVING flags.

Filesystems report case-insensitive or case-nonpreserving behavior
by setting these flags directly in fa->fsx_xflags. The default
(flags unset) indicates POSIX semantics: case-sensitive and
case-preserving. These flags are read-only; userspace cannot set
them via ioctl.

Remove struct file_kattr initialization from fileattr_fill_xflags()
and fileattr_fill_flags(). Callers at ioctl/syscall entry points
zero-initialize the struct themselves, which allows them to pass
hints (flags_valid, fsx_valid) to the filesystem's ->fileattr_get()
callback via the fa argument. Filesystem handlers that invoke these
fill functions can now set flags directly in fa->fsx_xflags before
calling them, without the fill functions zeroing those values.

In hindsight I regret not asking for the file_kattr initialization
change to be in a separate patch.

If I’m asked to post another revision of this series, I’ll look at splitting
1/16 into two patches.

quoted

Case sensitivity information is exported to userspace via the
fa_xflags field in the FS_IOC_FSGETXATTR ioctl and file_getattr()
system call.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The UAPI changes still look ok to me.  AFAICT the file_kattr
initialization now seem like they don't zap fields to confuse
vfs_fileattr_get.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

-- 
Chuck Lever