smb: client: fix chmod(2) regression with ATTR_READONLY

When the user sets a file or directory as read-only (e.g. ~S_IWUGO),
the client will set the ATTR_READONLY attribute by sending an
SMB2_SET_INFO request to the server in cifs_setattr_{,nounix}(), but
cifsInodeInfo::cifsAttrs will be left unchanged as the client will
only update the new file attributes in the next call to
{smb311_posix,cifs}_get_inode_info() with the new metadata filled in
@DaTa parameter.

Commit a18280e ("smb: cilent: set reparse mount points as
automounts") mistakenly removed the @DaTa NULL check when calling
is_inode_cache_good(), which broke the above case as the new
ATTR_READONLY attribute would end up not being updated on files with a
read lease.

Fix this by updating the inode whenever we have cached metadata in
@DaTa parameter.

Reported-by: Horst Reiterer <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: a18280e ("smb: cilent: set reparse mount points as automounts")
Cc: [email protected]
Signed-off-by: Paulo Alcantara (Red Hat) <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: Paulo Alcantara

fs/smb/client/inode.c

@@ -1408,7 +1408,7 @@ int cifs_get_inode_info(struct inode **inode,
 	struct cifs_fattr fattr = {};
 	int rc;
 
-	if (is_inode_cache_good(*inode)) {
+	if (!data && is_inode_cache_good(*inode)) {
 		cifs_dbg(FYI, "No need to revalidate cached inode sizes\n");
 		return 0;
 	}
@@ -1507,7 +1507,7 @@ int smb311_posix_get_inode_info(struct inode **inode,
 	struct cifs_fattr fattr = {};
 	int rc;
 
-	if (is_inode_cache_good(*inode)) {
+	if (!data && is_inode_cache_good(*inode)) {
 		cifs_dbg(FYI, "No need to revalidate cached inode sizes\n");
 		return 0;
 	}