[PATCH v9 04/17] exfat: Implement fileattr_get for case sensitivity

[Chuck Lever <cel@kernel.org>]

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

Report exFAT's case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. exFAT is always case-insensitive (using an upcase table for
comparison) and always preserves case at rest.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/exfat/exfat_fs.h |  2 ++
 fs/exfat/file.c     | 17 +++++++++++++++--
 fs/exfat/namei.c    |  1 +
 3 files changed, 18 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..8af829ef54c4 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 +324,17 @@ 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;
+	return 0;
+}
+
 int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr)
 {
@@ -817,6 +829,7 @@ 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