smb: client: move most of reparse point handling code to common file

In preparation to add support for creating special files also via WSL
reparse points in next commits.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/fs/smb/client/reparse.h b/fs/smb/client/reparse.h
new file mode 100644
index 000000000000..3ceb90da0df9
--- /dev/null
+++ b/fs/smb/client/reparse.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2024 Paulo Alcantara <pc@manguebit.com>
+ */
+
+#ifndef _CIFS_REPARSE_H
+#define _CIFS_REPARSE_H
+
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include "cifsglob.h"
+
+static inline dev_t reparse_nfs_mkdev(struct reparse_posix_data *buf)
+{
+	u64 v = le64_to_cpu(*(__le64 *)buf->DataBuffer);
+
+	return MKDEV(v >> 32, v & 0xffffffff);
+}
+
+static inline u64 reparse_mode_nfs_type(mode_t mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFBLK: return NFS_SPECFILE_BLK;
+	case S_IFCHR: return NFS_SPECFILE_CHR;
+	case S_IFIFO: return NFS_SPECFILE_FIFO;
+	case S_IFSOCK: return NFS_SPECFILE_SOCK;
+	}
+	return 0;
+}
+
+/*
+ * Match a reparse point inode if reparse tag and ctime haven't changed.
+ *
+ * Windows Server updates ctime of reparse points when their data have changed.
+ * The server doesn't allow changing reparse tags from existing reparse points,
+ * though it's worth checking.
+ */
+static inline bool reparse_inode_match(struct inode *inode,
+				       struct cifs_fattr *fattr)
+{
+	struct timespec64 ctime = inode_get_ctime(inode);
+
+	return (CIFS_I(inode)->cifsAttrs & ATTR_REPARSE) &&
+		CIFS_I(inode)->reparse_tag == fattr->cf_cifstag &&
+		timespec64_equal(&ctime, &fattr->cf_ctime);
+}
+
+static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
+{
+	struct smb2_file_all_info *fi = &data->fi;
+	u32 attrs = le32_to_cpu(fi->Attributes);
+	bool ret;
+
+	ret = data->reparse_point || (attrs & ATTR_REPARSE);
+	if (ret)
+		attrs |= ATTR_REPARSE;
+	fi->Attributes = cpu_to_le32(attrs);
+	return ret;
+}
+
+bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
+				 struct cifs_fattr *fattr,
+				 struct cifs_open_info_data *data);
+int smb2_create_reparse_symlink(const unsigned int xid, struct inode *inode,
+				struct dentry *dentry, struct cifs_tcon *tcon,
+				const char *full_path, const char *symname);
+int smb2_make_nfs_node(unsigned int xid, struct inode *inode,
+		       struct dentry *dentry, struct cifs_tcon *tcon,
+		       const char *full_path, umode_t mode, dev_t dev);
+int smb2_parse_reparse_point(struct cifs_sb_info *cifs_sb, struct kvec *rsp_iov,
+			     struct cifs_open_info_data *data);
+
+#endif /* _CIFS_REPARSE_H */