[PATCH v13 04/15] exfat: Implement fileattr_get for case sensitivity

Chuck Lever
2026-05-02T14:21:35Z

Report exFAT's case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. exFAT compares names through the volume's upcase table; in
practice that table folds case, and case is preserved at rest.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/exfat/exfat_fs.h | 2 ++
fs/exfat/file.c | 18 ++++++++++++++++--
fs/exfat/namei.c | 1 +
3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 89ef5368277f..aff4dcd4e75a 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -496,6 +496,8 @@ int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, unsigned int request_mask,
unsigned int query_flags);
+struct file_kattr;
+int exfat_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync);
long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 354bdcfe4abc..91e5511945d1 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -14,6 +14,7 @@
#include <linux/writeback.h>
#include <linux/filelock.h>
#include <linux/falloc.h>
+#include <linux/fileattr.h>

#include "exfat_raw.h"
#include "exfat_fs.h"
@@ -323,6 +324,18 @@ int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
return 0;
}

+int exfat_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ /*
+ * exFAT compares filenames through an upcase table, so lookup
+ * is always case-insensitive. Long names are stored in UTF-16
+ * with case intact; CASENONPRESERVING stays clear.
+ */
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ fa->flags |= FS_CASEFOLD_FL;
+ return 0;
+}
+
int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr)
{
@@ -817,6 +830,7 @@ const struct file_operations exfat_file_operations = {
};

const struct inode_operations exfat_file_inode_operations = {
- .setattr = exfat_setattr,
- .getattr = exfat_getattr,
+ .setattr = exfat_setattr,
+ .getattr = exfat_getattr,
+ .fileattr_get = exfat_fileattr_get,
};
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index 2c5636634b4a..94002e43db08 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -1311,4 +1311,5 @@ const struct inode_operations exfat_dir_inode_operations = {
.rename = exfat_rename,
.setattr = exfat_setattr,
.getattr = exfat_getattr,
+ .fileattr_get = exfat_fileattr_get,
};

--
2.53.0