[PATCH v9 12/17] f2fs: Add case sensitivity reporting to fileattr_get

Chuck Lever
2026-04-22T23:30:46Z

NFS and other remote filesystem protocols need to determine
whether a local filesystem performs case-insensitive lookups
so they can provide correct semantics to clients. Without
this information, f2fs exports cannot properly advertise
their filename case behavior.

Report f2fs case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. Like ext4, f2fs supports per-directory case folding via
the casefold flag (IS_CASEFOLDED). f2fs always preserves case
at rest.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/f2fs/file.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index fb12c5c9affd..347568ff0d58 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3463,6 +3463,14 @@ int f2fs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
if (f2fs_sb_has_project_quota(F2FS_I_SB(inode)))
fa->fsx_projid = from_kprojid(&init_user_ns, fi->i_projid);

+ /*
+ * Casefold is a per-directory attribute in f2fs; the on-disk
+ * name is preserved regardless. Report FS_XFLAG_CASEFOLD for
+ * casefolded directories so callers (e.g. NFS export) can
+ * advertise case-insensitive lookup semantics for that tree.
+ */
+ if (IS_CASEFOLDED(inode))
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
return 0;
}

--
2.53.0