On Thu, Jan 22, 2026, at 7:29 PM, Darrick J. Wong wrote:

On Thu, Jan 22, 2026 at 11:03:02AM -0500, Chuck Lever wrote:

quoted

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

Report ext4's case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. ext4 always preserves case at rest.

Case sensitivity is a per-directory setting in ext4. If the queried
inode is a casefolded directory, report case-insensitive; otherwise
report case-sensitive (standard POSIX behavior).

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/ext4/ioctl.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 7ce0fc40aec2..462da7aadc80 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c

@@ -996,6 +996,13 @@ int ext4_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
 	if (ext4_has_feature_project(inode->i_sb))
 		fa->fsx_projid = from_kprojid(&init_user_ns, ei->i_projid);
 
+	/*
+	 * Case folding is a directory attribute in ext4. Set FS_XFLAG_CASEFOLD
+	 * for directories with the casefold attribute; all other inodes use
+	 * standard case-sensitive semantics.
+	 */
+	if (IS_CASEFOLDED(inode))
+		fa->fsx_xflags |= FS_XFLAG_CASEFOLD;

Curious.  Shouldn't the VFS set FS_XFLAG_CASEFOLD if the VFS casefolding
flag is set?

OTOH, there are more filesystems that apparently support casefolding
(given the size of this patchset) than actually set S_CASEFOLD.  I think
I'm ignorant of something here...

I'm not clear if there's a review action needed. Help?


-- 
Chuck Lever