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 /** 18 * nlm_fopen - Open an NFSD file 19 * @rqstp: NLM RPC procedure execution context 20 * @f: NFS file handle to be opened 21 * @filp: OUT: an opened struct file 22 * @flags: the POSIX open flags to use 23 * 24 * nlm_fopen() holds the dentry reference until nlm_fclose() releases it. 25 * 26 * Returns zero on success or a negative errno value if the file 27 * cannot be opened. 28 */ 29 static int nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, 30 struct file **filp, int flags) 31 { 32 __be32 nfserr; 33 int access; 34 struct svc_fh fh; 35 36 /* must initialize before using! but maxsize doesn't matter */ 37 fh_init(&fh,0); 38 fh.fh_handle.fh_size = f->size; 39 memcpy(&fh.fh_handle.fh_raw, f->data, f->size); 40 fh.fh_export = NULL; 41 42 /* 43 * Allow BYPASS_GSS as some client implementations use AUTH_SYS 44 * for NLM even when GSS is used for NFS. 45 * Allow OWNER_OVERRIDE as permission might have been changed 46 * after the file was opened. 47 * Pass MAY_NLM so that authentication can be completely bypassed 48 * if NFSEXP_NOAUTHNLM is set. Some older clients use AUTH_NULL 49 * for NLM requests. 50 */ 51 access = (flags == O_WRONLY) ? NFSD_MAY_WRITE : NFSD_MAY_READ; 52 access |= NFSD_MAY_NLM | NFSD_MAY_OWNER_OVERRIDE | NFSD_MAY_BYPASS_GSS; 53 nfserr = nfsd_open(rqstp, &fh, S_IFREG, access, filp); 54 fh_put(&fh); 55 56 switch (nfserr) { 57 case nfs_ok: 58 break; 59 case nfserr_jukebox: 60 /* 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 fails 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 -EWOULDBLOCK; 75 case nfserr_stale: 76 return -ESTALE; 77 default: 78 return -ENOLCK; 79 } 80 81 return 0; 82 } 83 84 /** 85 * nlm_fclose - Close an NFSD file 86 * @filp: a struct file that was opened by nlm_fopen() 87 */ 88 static void 89 nlm_fclose(struct file *filp) 90 { 91 fput(filp); 92 } 93 94 static const struct nlmsvc_binding nfsd_nlm_ops = { 95 .fopen = nlm_fopen, /* open file for locking */ 96 .fclose = nlm_fclose, /* close file */ 97 }; 98 99 void 100 nfsd_lockd_init(void) 101 { 102 dprintk("nfsd: initializing lockd\n"); 103 nlmsvc_ops = &nfsd_nlm_ops; 104 } 105 106 void 107 nfsd_lockd_shutdown(void) 108 { 109 nlmsvc_ops = NULL; 110 } 111