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

Report NTFS case sensitivity behavior via the new file_kattr
case_info field. NTFS always preserves case at rest.

Case sensitivity depends on mount options: with "nocase", NTFS
performs Unicode case-insensitive matching; otherwise it is
case-sensitive.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/ntfs3/file.c    | 27 +++++++++++++++++++++++++++
 fs/ntfs3/inode.c   |  1 +
 fs/ntfs3/namei.c   |  2 ++
 fs/ntfs3/ntfs_fs.h |  1 +
 4 files changed, 31 insertions(+)

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 4c90ec2fa2ea..35892988b788 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -104,6 +104,32 @@ long ntfs_compat_ioctl(struct file *filp, u32 cmd, unsigned long arg)
 }
 #endif
 
+/*
+ * ntfs_fileattr_get - inode_operations::fileattr_get
+ */
+int ntfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ntfs_sb_info *sbi = inode->i_sb->s_fs_info;
+
+	/* Avoid any operation if inode is bad. */
+	if (unlikely(is_bad_ni(ntfs_i(inode))))
+		return -EINVAL;
+
+	/*
+	 * NTFS preserves case. Case sensitivity depends on mount options:
+	 * with "nocase" mount option, NTFS is case-insensitive using
+	 * Unicode case folding; otherwise it is case-sensitive.
+	 */
+	if (sbi->options && sbi->options->nocase)
+		fa->case_info = FILEATTR_CASEFOLD_UNICODE |
+				FILEATTR_CASE_PRESERVING;
+	else
+		fa->case_info = FILEATTR_CASEFOLD_NONE |
+				FILEATTR_CASE_PRESERVING;
+	return 0;
+}
+
 /*
  * ntfs_getattr - inode_operations::getattr
  */
@@ -1383,6 +1409,7 @@ const struct inode_operations ntfs_file_inode_operations = {
 	.get_acl	= ntfs_get_acl,
 	.set_acl	= ntfs_set_acl,
 	.fiemap		= ntfs_fiemap,
+	.fileattr_get	= ntfs_fileattr_get,
 };
 
 const struct file_operations ntfs_file_operations = {
diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 3959f23c487a..ecdea6d83980 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -2085,6 +2085,7 @@ const struct inode_operations ntfs_link_inode_operations = {
 	.get_link	= ntfs_get_link,
 	.setattr	= ntfs_setattr,
 	.listxattr	= ntfs_listxattr,
+	.fileattr_get	= ntfs_fileattr_get,
 };
 
 const struct address_space_operations ntfs_aops = {
diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index 82c8ae56beee..2094e5409e43 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -519,6 +519,7 @@ const struct inode_operations ntfs_dir_inode_operations = {
 	.getattr	= ntfs_getattr,
 	.listxattr	= ntfs_listxattr,
 	.fiemap		= ntfs_fiemap,
+	.fileattr_get	= ntfs_fileattr_get,
 };
 
 const struct inode_operations ntfs_special_inode_operations = {
@@ -527,6 +528,7 @@ const struct inode_operations ntfs_special_inode_operations = {
 	.listxattr	= ntfs_listxattr,
 	.get_acl	= ntfs_get_acl,
 	.set_acl	= ntfs_set_acl,
+	.fileattr_get	= ntfs_fileattr_get,
 };
 
 const struct dentry_operations ntfs_dentry_ops = {
diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
index 630128716ea7..a178ca66e2e0 100644
--- a/fs/ntfs3/ntfs_fs.h
+++ b/fs/ntfs3/ntfs_fs.h
@@ -503,6 +503,7 @@ extern const struct file_operations ntfs_dir_operations;
 extern const struct file_operations ntfs_legacy_dir_operations;
 
 /* Globals from file.c */
+int ntfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
 int ntfs_getattr(struct mnt_idmap *idmap, const struct path *path,
 		 struct kstat *stat, u32 request_mask, u32 flags);
 int ntfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
-- 
2.52.0