lockd.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * This file contains all the stubs needed when communicating with lockd.
  4 * This level of indirection is necessary so we can run nfsd+lockd without
  5 * requiring the nfs client to be compiled in/loaded, and vice versa.
  6 *
  7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  8 */
  9
 10#include <linux/file.h>
 11#include <linux/lockd/bind.h>
 12#include "nfsd.h"
 13#include "vfs.h"
 14
 15#define NFSDDBG_FACILITY		NFSDDBG_LOCKD
 16
 17#ifdef CONFIG_LOCKD_V4
 18#define nlm_stale_fh	nlm4_stale_fh
 19#define nlm_failed	nlm4_failed
 20#else
 21#define nlm_stale_fh	nlm_lck_denied_nolocks
 22#define nlm_failed	nlm_lck_denied_nolocks
 23#endif
 24/*
 25 * Note: we hold the dentry use count while the file is open.
 26 */
 27static __be32
 28nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, struct file **filp,
 29		int mode)
 30{
 31	__be32		nfserr;
 32	int		access;
 33	struct svc_fh	fh;
 34
 35	/* must initialize before using! but maxsize doesn't matter */
 36	fh_init(&fh,0);
 37	fh.fh_handle.fh_size = f->size;
 38	memcpy(&fh.fh_handle.fh_raw, f->data, f->size);
 39	fh.fh_export = NULL;
 40
 41	/*
 42	 * Allow BYPASS_GSS as some client implementations use AUTH_SYS
 43	 * for NLM even when GSS is used for NFS.
 44	 * Allow OWNER_OVERRIDE as permission might have been changed
 45	 * after the file was opened.
 46	 * Pass MAY_NLM so that authentication can be completely bypassed
 47	 * if NFSEXP_NOAUTHNLM is set.  Some older clients use AUTH_NULL
 48	 * for NLM requests.
 49	 */
 50	access = (mode == O_WRONLY) ? NFSD_MAY_WRITE : NFSD_MAY_READ;
 51	access |= NFSD_MAY_NLM | NFSD_MAY_OWNER_OVERRIDE | NFSD_MAY_BYPASS_GSS;
 52	nfserr = nfsd_open(rqstp, &fh, S_IFREG, access, filp);
 53	fh_put(&fh);
 54	/* We return nlm error codes as nlm doesn't know
 55	 * about nfsd, but nfsd does know about nlm..
 56	 */
 57	switch (nfserr) {
 58	case nfs_ok:
 59		return 0;
 60	case nfserr_jukebox:
 61		/* this error can indicate a presence of a conflicting
 62		 * delegation to an NLM lock request. Options are:
 63		 * (1) For now, drop this request and make the client
 64		 * retry. When delegation is returned, client's lock retry
 65		 * will complete.
 66		 * (2) NLM4_DENIED as per "spec" signals to the client
 67		 * that the lock is unavailable now but client can retry.
 68		 * Linux client implementation does not. It treats
 69		 * NLM4_DENIED same as NLM4_FAILED and errors the request.
 70		 * (3) For the future, treat this as blocked lock and try
 71		 * to callback when the delegation is returned but might
 72		 * not have a proper lock request to block on.
 73		 */
 74		return nlm_drop_reply;
 75	case nfserr_stale:
 76		return nlm_stale_fh;
 77	default:
 78		return nlm_failed;
 79	}
 80}
 81
 82static void
 83nlm_fclose(struct file *filp)
 84{
 85	fput(filp);
 86}
 87
 88static const struct nlmsvc_binding nfsd_nlm_ops = {
 89	.fopen		= nlm_fopen,		/* open file for locking */
 90	.fclose		= nlm_fclose,		/* close file */
 91};
 92
 93void
 94nfsd_lockd_init(void)
 95{
 96	dprintk("nfsd: initializing lockd\n");
 97	nlmsvc_ops = &nfsd_nlm_ops;
 98}
 99
100void
101nfsd_lockd_shutdown(void)
102{
103	nlmsvc_ops = NULL;
104}