nfs_lock.c revision 304843
1/*- 2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Berkeley Software Design Inc's name may not be used to endorse or 13 * promote products derived from this software without specific prior 14 * written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * from BSDI nfs_lock.c,v 2.4 1998/12/14 23:49:56 jch Exp 29 */ 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD: stable/11/sys/nfs/nfs_lock.c 304843 2016-08-26 10:04:10Z kib $"); 33 34#include <sys/param.h> 35#include <sys/systm.h> 36#include <sys/conf.h> 37#include <sys/fcntl.h> 38#include <sys/kernel.h> /* for hz */ 39#include <sys/limits.h> 40#include <sys/lock.h> 41#include <sys/malloc.h> 42#include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */ 43#include <sys/mbuf.h> 44#include <sys/mount.h> 45#include <sys/namei.h> 46#include <sys/priv.h> 47#include <sys/proc.h> 48#include <sys/resourcevar.h> 49#include <sys/socket.h> 50#include <sys/socket.h> 51#include <sys/unistd.h> 52#include <sys/vnode.h> 53 54#include <net/if.h> 55 56#include <nfs/nfsproto.h> 57#include <nfs/nfs_lock.h> 58#include <nfsclient/nfs.h> 59#include <nfsclient/nfsmount.h> 60#include <nfsclient/nfsnode.h> 61#include <nfsclient/nlminfo.h> 62 63extern void (*nlminfo_release_p)(struct proc *p); 64 65vop_advlock_t *nfs_advlock_p = nfs_dolock; 66vop_reclaim_t *nfs_reclaim_p = NULL; 67 68static MALLOC_DEFINE(M_NFSLOCK, "nfsclient_lock", "NFS lock request"); 69static MALLOC_DEFINE(M_NLMINFO, "nfsclient_nlminfo", 70 "NFS lock process structure"); 71 72static int nfslockdans(struct thread *td, struct lockd_ans *ansp); 73static void nlminfo_release(struct proc *p); 74/* 75 * -------------------------------------------------------------------- 76 * A miniature device driver which the userland uses to talk to us. 77 * 78 */ 79 80static struct cdev *nfslock_dev; 81static struct mtx nfslock_mtx; 82static int nfslock_isopen; 83static TAILQ_HEAD(,__lock_msg) nfslock_list; 84 85static int 86nfslock_open(struct cdev *dev, int oflags, int devtype, struct thread *td) 87{ 88 int error; 89 90 error = priv_check(td, PRIV_NFS_LOCKD); 91 if (error) 92 return (error); 93 94 mtx_lock(&nfslock_mtx); 95 if (!nfslock_isopen) { 96 error = 0; 97 nfslock_isopen = 1; 98 } else { 99 error = EOPNOTSUPP; 100 } 101 mtx_unlock(&nfslock_mtx); 102 103 return (error); 104} 105 106static int 107nfslock_close(struct cdev *dev, int fflag, int devtype, struct thread *td) 108{ 109 struct __lock_msg *lm; 110 111 mtx_lock(&nfslock_mtx); 112 nfslock_isopen = 0; 113 while (!TAILQ_EMPTY(&nfslock_list)) { 114 lm = TAILQ_FIRST(&nfslock_list); 115 /* XXX: answer request */ 116 TAILQ_REMOVE(&nfslock_list, lm, lm_link); 117 free(lm, M_NFSLOCK); 118 } 119 mtx_unlock(&nfslock_mtx); 120 return (0); 121} 122 123static int 124nfslock_read(struct cdev *dev, struct uio *uio, int ioflag) 125{ 126 int error; 127 struct __lock_msg *lm; 128 129 if (uio->uio_resid != sizeof *lm) 130 return (EOPNOTSUPP); 131 lm = NULL; 132 error = 0; 133 mtx_lock(&nfslock_mtx); 134 while (TAILQ_EMPTY(&nfslock_list)) { 135 error = msleep(&nfslock_list, &nfslock_mtx, PSOCK | PCATCH, 136 "nfslockd", 0); 137 if (error) 138 break; 139 } 140 if (!error) { 141 lm = TAILQ_FIRST(&nfslock_list); 142 TAILQ_REMOVE(&nfslock_list, lm, lm_link); 143 } 144 mtx_unlock(&nfslock_mtx); 145 if (!error) { 146 error = uiomove(lm, sizeof *lm, uio); 147 free(lm, M_NFSLOCK); 148 } 149 return (error); 150} 151 152static int 153nfslock_write(struct cdev *dev, struct uio *uio, int ioflag) 154{ 155 struct lockd_ans la; 156 int error; 157 158 if (uio->uio_resid != sizeof la) 159 return (EOPNOTSUPP); 160 error = uiomove(&la, sizeof la, uio); 161 if (!error) 162 error = nfslockdans(curthread, &la); 163 return (error); 164} 165 166static int 167nfslock_send(struct __lock_msg *lm) 168{ 169 struct __lock_msg *lm2; 170 int error; 171 172 error = 0; 173 lm2 = malloc(sizeof *lm2, M_NFSLOCK, M_WAITOK); 174 mtx_lock(&nfslock_mtx); 175 if (nfslock_isopen) { 176 memcpy(lm2, lm, sizeof *lm2); 177 TAILQ_INSERT_TAIL(&nfslock_list, lm2, lm_link); 178 wakeup(&nfslock_list); 179 } else { 180 error = EOPNOTSUPP; 181 } 182 mtx_unlock(&nfslock_mtx); 183 if (error) 184 free(lm2, M_NFSLOCK); 185 return (error); 186} 187 188static struct cdevsw nfslock_cdevsw = { 189 .d_version = D_VERSION, 190 .d_open = nfslock_open, 191 .d_close = nfslock_close, 192 .d_read = nfslock_read, 193 .d_write = nfslock_write, 194 .d_name = "nfslock" 195}; 196 197static int 198nfslock_modevent(module_t mod __unused, int type, void *data __unused) 199{ 200 201 switch (type) { 202 case MOD_LOAD: 203 if (bootverbose) 204 printf("nfslock: pseudo-device\n"); 205 mtx_init(&nfslock_mtx, "nfslock", NULL, MTX_DEF); 206 TAILQ_INIT(&nfslock_list); 207 nlminfo_release_p = nlminfo_release; 208 nfslock_dev = make_dev(&nfslock_cdevsw, 0, 209 UID_ROOT, GID_KMEM, 0600, _PATH_NFSLCKDEV); 210 return (0); 211 default: 212 return (EOPNOTSUPP); 213 } 214} 215 216DEV_MODULE(nfslock, nfslock_modevent, NULL); 217MODULE_VERSION(nfslock, 1); 218 219 220/* 221 * XXX 222 * We have to let the process know if the call succeeded. I'm using an extra 223 * field in the p_nlminfo field in the proc structure, as it is already for 224 * lockd stuff. 225 */ 226 227/* 228 * nfs_advlock -- 229 * NFS advisory byte-level locks. 230 * 231 * The vnode shall be (shared) locked on the entry, it is 232 * unconditionally unlocked after. 233 */ 234int 235nfs_dolock(struct vop_advlock_args *ap) 236{ 237 LOCKD_MSG msg; 238 struct thread *td; 239 struct vnode *vp; 240 int error; 241 struct flock *fl; 242 struct proc *p; 243 struct nfsmount *nmp; 244 struct timeval boottime; 245 246 td = curthread; 247 p = td->td_proc; 248 249 vp = ap->a_vp; 250 fl = ap->a_fl; 251 nmp = VFSTONFS(vp->v_mount); 252 253 ASSERT_VOP_LOCKED(vp, "nfs_dolock"); 254 255 nmp->nm_getinfo(vp, msg.lm_fh, &msg.lm_fh_len, &msg.lm_addr, 256 &msg.lm_nfsv3, NULL, NULL); 257 VOP_UNLOCK(vp, 0); 258 259 /* 260 * the NLM protocol doesn't allow the server to return an error 261 * on ranges, so we do it. 262 */ 263 if (fl->l_whence != SEEK_END) { 264 if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) || 265 fl->l_start < 0 || 266 (fl->l_len < 0 && 267 (fl->l_start == 0 || fl->l_start + fl->l_len < 0))) 268 return (EINVAL); 269 if (fl->l_len > 0 && 270 (fl->l_len - 1 > OFF_MAX - fl->l_start)) 271 return (EOVERFLOW); 272 } 273 274 /* 275 * Fill in the information structure. 276 */ 277 msg.lm_version = LOCKD_MSG_VERSION; 278 msg.lm_msg_ident.pid = p->p_pid; 279 280 mtx_lock(&Giant); 281 /* 282 * if there is no nfsowner table yet, allocate one. 283 */ 284 if (p->p_nlminfo == NULL) { 285 p->p_nlminfo = malloc(sizeof(struct nlminfo), 286 M_NLMINFO, M_WAITOK | M_ZERO); 287 p->p_nlminfo->pid_start = p->p_stats->p_start; 288 getboottime(&boottime); 289 timevaladd(&p->p_nlminfo->pid_start, &boottime); 290 } 291 msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start; 292 msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq); 293 294 msg.lm_fl = *fl; 295 msg.lm_wait = ap->a_flags & F_WAIT; 296 msg.lm_getlk = ap->a_op == F_GETLK; 297 cru2x(td->td_ucred, &msg.lm_cred); 298 299 for (;;) { 300 error = nfslock_send(&msg); 301 if (error) 302 goto out; 303 304 /* Unlocks succeed immediately. */ 305 if (fl->l_type == F_UNLCK) 306 goto out; 307 308 /* 309 * Retry after 20 seconds if we haven't gotten a response yet. 310 * This number was picked out of thin air... but is longer 311 * then even a reasonably loaded system should take (at least 312 * on a local network). XXX Probably should use a back-off 313 * scheme. 314 * 315 * XXX: No PCATCH here since we currently have no useful 316 * way to signal to the userland rpc.lockd that the request 317 * has been aborted. Once the rpc.lockd implementation 318 * can handle aborts, and we report them properly, 319 * PCATCH can be put back. In the mean time, if we did 320 * permit aborting, the lock attempt would "get lost" 321 * and the lock would get stuck in the locked state. 322 */ 323 error = tsleep(p->p_nlminfo, PUSER, "lockd", 20*hz); 324 if (error != 0) { 325 if (error == EWOULDBLOCK) { 326 /* 327 * We timed out, so we rewrite the request 328 * to the fifo. 329 */ 330 continue; 331 } 332 333 break; 334 } 335 336 if (msg.lm_getlk && p->p_nlminfo->retcode == 0) { 337 if (p->p_nlminfo->set_getlk_pid) { 338 fl->l_sysid = 0; /* XXX */ 339 fl->l_pid = p->p_nlminfo->getlk_pid; 340 } else { 341 fl->l_type = F_UNLCK; 342 } 343 } 344 error = p->p_nlminfo->retcode; 345 break; 346 } 347 out: 348 mtx_unlock(&Giant); 349 return (error); 350} 351 352/* 353 * nfslockdans -- 354 * NFS advisory byte-level locks answer from the lock daemon. 355 */ 356static int 357nfslockdans(struct thread *td, struct lockd_ans *ansp) 358{ 359 struct proc *targetp; 360 361 /* the version should match, or we're out of sync */ 362 if (ansp->la_vers != LOCKD_ANS_VERSION) 363 return (EINVAL); 364 365 /* Find the process, set its return errno and wake it up. */ 366 if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL) 367 return (ESRCH); 368 369 /* verify the pid hasn't been reused (if we can), and it isn't waiting 370 * for an answer from a more recent request. We return an EPIPE if 371 * the match fails, because we've already used ESRCH above, and this 372 * is sort of like writing on a pipe after the reader has closed it. 373 */ 374 if (targetp->p_nlminfo == NULL || 375 ((ansp->la_msg_ident.msg_seq != -1) && 376 (timevalcmp(&targetp->p_nlminfo->pid_start, 377 &ansp->la_msg_ident.pid_start, !=) || 378 targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) { 379 PROC_UNLOCK(targetp); 380 return (EPIPE); 381 } 382 383 targetp->p_nlminfo->retcode = ansp->la_errno; 384 targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid; 385 targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid; 386 387 wakeup(targetp->p_nlminfo); 388 389 PROC_UNLOCK(targetp); 390 return (0); 391} 392 393/* 394 * Free nlminfo attached to process. 395 */ 396void 397nlminfo_release(struct proc *p) 398{ 399 free(p->p_nlminfo, M_NLMINFO); 400 p->p_nlminfo = NULL; 401} 402