[PATCH v2 07/10] ntfs: add fileattr query support

[Baolin Liu <liubaolin12138@163.com>]

From: Baolin Liu <liubaolin@kylinos.cn>

Add fileattr_get operations for files and directories, as well as the
existing symlink and special inode operation tables. Report compression,
encryption, immutable and append-only from cached inode state, and
FS_CASEFOLD_FL from the mount-wide case sensitivity policy.

This introduces querying only. It neither reads a private flag EA nor
allows userspace to change the reported flags.

Signed-off-by: Baolin Liu <liubaolin@kylinos.cn>
---
 Documentation/filesystems/ntfs.rst |  8 ++++++++
 fs/ntfs/file.c                     | 33 ++++++++++++++++++++++++++++++
 fs/ntfs/namei.c                    |  1 +
 fs/ntfs/ntfs.h                     |  2 ++
 4 files changed, 44 insertions(+)

diff --git a/Documentation/filesystems/ntfs.rst b/Documentation/filesystems/ntfs.rst
index 4bfa392daec6..0a4c43d6c890 100644
--- a/Documentation/filesystems/ntfs.rst
+++ b/Documentation/filesystems/ntfs.rst
@@ -9,6 +9,7 @@ The Linux NTFS filesystem driver
 
    - Overview
    - Utilities support
+   - Linux file attributes
    - Supported mount options
 
 
@@ -34,6 +35,13 @@ The project is available at:
   https://github.com/ntfsprogs-plus/ntfsprogs-plus
 
 
+Linux file attributes
+=====================
+
+The driver supports querying compression, encryption, immutable, append-only
+and mount-wide case folding through lsattr(1). Case folding is reported
+according to the mount options.
+
 Supported mount options
 =======================
 
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 99a2c7a5cf81..e5846bf498b0 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -15,6 +15,7 @@
 #include <linux/posix_acl_xattr.h>
 #include <linux/compat.h>
 #include <linux/falloc.h>
+#include <linux/fileattr.h>
 
 #include "lcnalloc.h"
 #include "ntfs.h"
@@ -136,6 +137,35 @@ static int ntfs_file_release(struct inode *vi, struct file *filp)
 	return 0;
 }
 
+/*
+ * ntfs_fileattr_get - inode_operations::fileattr_get
+ * @dentry:	dentry to report the flags of
+ * @fa:		filled in with the flags of @dentry
+ */
+int ntfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+	struct inode *vi = d_inode(dentry);
+	struct ntfs_inode *ni = NTFS_I(vi);
+	u32 flags = 0;
+
+	if (NVolShutdown(ni->vol))
+		return -EIO;
+
+	if (NInoCompressed(ni) || NInoWofCompressed(ni))
+		flags |= FS_COMPR_FL;
+	if (NInoEncrypted(ni))
+		flags |= FS_ENCRYPT_FL;
+	if (vi->i_flags & S_IMMUTABLE)
+		flags |= FS_IMMUTABLE_FL;
+	if (vi->i_flags & S_APPEND)
+		flags |= FS_APPEND_FL;
+	if (!NVolCaseSensitive(ni->vol))
+		flags |= FS_CASEFOLD_FL;
+
+	fileattr_fill_flags(fa, flags);
+	return 0;
+}
+
 /*
  * ntfs_file_fsync - sync a file to disk
  * @filp:	file to be synced
@@ -1234,6 +1264,7 @@ const struct file_operations ntfs_file_ops = {
 };
 
 const struct inode_operations ntfs_file_inode_ops = {
+	.fileattr_get	= ntfs_fileattr_get,
 	.setattr	= ntfs_setattr,
 	.getattr	= ntfs_getattr,
 	.listxattr	= ntfs_listxattr,
@@ -1243,12 +1274,14 @@ const struct inode_operations ntfs_file_inode_ops = {
 };
 
 const struct inode_operations ntfs_symlink_inode_operations = {
+	.fileattr_get	= ntfs_fileattr_get,
 	.get_link	= ntfs_get_link,
 	.setattr	= ntfs_setattr,
 	.listxattr	= ntfs_listxattr,
 };
 
 const struct inode_operations ntfs_special_inode_operations = {
+	.fileattr_get	= ntfs_fileattr_get,
 	.setattr	= ntfs_setattr,
 	.getattr	= ntfs_getattr,
 	.listxattr	= ntfs_listxattr,
diff --git a/fs/ntfs/namei.c b/fs/ntfs/namei.c
index 3e0adb9a0ea4..ee451700b766 100644
--- a/fs/ntfs/namei.c
+++ b/fs/ntfs/namei.c
@@ -1548,6 +1548,7 @@ static int ntfs_link(struct dentry *old_dentry, struct inode *dir,
  * Inode operations for directories.
  */
 const struct inode_operations ntfs_dir_inode_ops = {
+	.fileattr_get	= ntfs_fileattr_get,
 	.lookup		= ntfs_lookup,	/* VFS: Lookup directory. */
 	.create		= ntfs_create,
 	.unlink		= ntfs_unlink,
diff --git a/fs/ntfs/ntfs.h b/fs/ntfs/ntfs.h
index dd56894762a9..a5c5c18671d2 100644
--- a/fs/ntfs/ntfs.h
+++ b/fs/ntfs/ntfs.h
@@ -183,6 +183,8 @@ extern const struct inode_operations ntfs_dir_inode_ops;
 extern const struct  file_operations ntfs_empty_file_ops;
 extern const struct inode_operations ntfs_empty_inode_ops;
 
+int ntfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
+
 extern const struct export_operations ntfs_export_ops;
 
 /*
-- 
2.51.0