[PATCH 1/2] cifs: Do not attempt to call CIFSSMBRenameOpenFile() without CAP_INFOLEVEL_PASSTHRU

["Pali Rohár" <pali@kernel.org>]

CIFSSMBRenameOpenFile() uses SMB_SET_FILE_RENAME_INFORMATION (0x3f2) level
which is SMB PASSTHROUGH level (>= 0x03e8). SMB PASSTHROUGH levels are
supported only when server announce CAP_INFOLEVEL_PASSTHRU.

All usage of CIFSSMBRenameOpenFile() execept the one is already guarded by
checks which prevents calling it against servers without support for
CAP_INFOLEVEL_PASSTHRU.

The remaning usage without guard is in cifs_do_rename() function, so add
missing guard here.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 fs/smb/client/inode.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index ac408e3e0478..9393a9c18010 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -2408,6 +2408,13 @@ cifs_do_rename(const unsigned int xid, struct dentry *from_dentry,
 	if (to_dentry->d_parent != from_dentry->d_parent)
 		goto do_rename_exit;
 
+	/*
+	 * CIFSSMBRenameOpenFile() uses SMB_SET_FILE_RENAME_INFORMATION
+	 * which is SMB PASSTHROUGH level.
+	 */
+	if (!(tcon->ses->capabilities & CAP_INFOLEVEL_PASSTHRU))
+		goto do_rename_exit;
+
 	oparms = (struct cifs_open_parms) {
 		.tcon = tcon,
 		.cifs_sb = cifs_sb,
-- 
2.20.1