NFSv4: nfs4_proc_set_acl needs to restore NFS_CAP_UIDGID_NOMAP on error.

Currently if __nfs4_proc_set_acl fails with NFS4ERR_BADOWNER it
re-enables the idmapper by clearing NFS_CAP_UIDGID_NOMAP before
retrying again. The NFS_CAP_UIDGID_NOMAP remains cleared even if
the retry fails. This causes problem for subsequent setattr
requests for v4 server that does not have idmapping configured.

This patch modifies nfs4_proc_set_acl to detect NFS4ERR_BADOWNER
and NFS4ERR_BADNAME and skips the retry, since the kernel isn't
involved in encoding the ACEs, and return -EINVAL.

Steps to reproduce the problem:

 # mount -o vers=4.1,sec=sys server:/export/test /tmp/mnt
 # touch /tmp/mnt/file1
 # chown 99 /tmp/mnt/file1
 # nfs4_setfacl -a A::unknown.user@xyz.com:wrtncy /tmp/mnt/file1
 Failed setxattr operation: Invalid argument
 # chown 99 /tmp/mnt/file1
 chown: changing ownership of ‘/tmp/mnt/file1’: Invalid argument
 # umount /tmp/mnt
 # mount -o vers=4.1,sec=sys server:/export/test /tmp/mnt
 # chown 99 /tmp/mnt/file1
 #

v2: detect NFS4ERR_BADOWNER and NFS4ERR_BADNAME and skip retry
       in nfs4_proc_set_acl.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Author: daimngo

fs/nfs/nfs4proc.c

@@ -5968,6 +5968,14 @@ static int nfs4_proc_set_acl(struct inode *inode, const void *buf, size_t buflen
 	do {
 		err = __nfs4_proc_set_acl(inode, buf, buflen);
 		trace_nfs4_set_acl(inode, err);
+		if (err == -NFS4ERR_BADOWNER || err == -NFS4ERR_BADNAME) {
+			/*
+			 * no need to retry since the kernel
+			 * isn't involved in encoding the ACEs.
+			 */
+			err = -EINVAL;
+			break;
+		}
 		err = nfs4_handle_exception(NFS_SERVER(inode), err,
 				&exception);
 	} while (exception.retry);