From 4ca691a892e8ab4f79583de1394f17a7dcfa2b57 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@redhat.com>
Date: Thu, 22 May 2008 09:33:34 -0400
Subject: [PATCH] silently ignore ownership changes unless unix extensions are
 enabled or we're faking uid changes

CIFS currently allows you to change the ownership of a file, but unless
unix extensions are enabled this change is not passed off to the server.

Have CIFS silently ignore ownership changes that can't be persistently
stored on the server unless the "setuids" option is explicitly
specified.

We could return an error here (-EOPNOTSUPP or something), but this is
how most disk-based windows filesystems on behave on Linux (e.g.  VFAT,
NTFS, etc). With cifsacl support and proper Windows to Unix idmapping
support, we may be able to do this more properly in the future.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
---
 fs/cifs/inode.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index ae6b725b3665..fe752fdb26c3 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1546,13 +1546,26 @@ int cifs_setattr(struct dentry *direntry, struct iattr *attrs)
 		} else
 			goto cifs_setattr_exit;
 	}
-	if (attrs->ia_valid & ATTR_UID) {
-		cFYI(1, ("UID changed to %d", attrs->ia_uid));
-		uid = attrs->ia_uid;
-	}
-	if (attrs->ia_valid & ATTR_GID) {
-		cFYI(1, ("GID changed to %d", attrs->ia_gid));
-		gid = attrs->ia_gid;
+
+	/*
+	 * Without unix extensions we can't send ownership changes to the
+	 * server, so silently ignore them. This is consistent with how
+	 * local DOS/Windows filesystems behave (VFAT, NTFS, etc). With
+	 * CIFSACL support + proper Windows to Unix idmapping, we may be
+	 * able to support this in the future.
+	 */
+	if (!pTcon->unix_ext &&
+	    !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID)) {
+		attrs->ia_valid &= ~(ATTR_UID | ATTR_GID);
+	} else {
+		if (attrs->ia_valid & ATTR_UID) {
+			cFYI(1, ("UID changed to %d", attrs->ia_uid));
+			uid = attrs->ia_uid;
+		}
+		if (attrs->ia_valid & ATTR_GID) {
+			cFYI(1, ("GID changed to %d", attrs->ia_gid));
+			gid = attrs->ia_gid;
+		}
 	}
 
 	time_buf.Attributes = 0;
-- 
2.34.1