1 /* 2 * Copyright (c) 2004 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * Copyright (c) 1989, 1993 35 * The Regents of the University of California. All rights reserved. 36 * (c) UNIX System Laboratories, Inc. 37 * All or some portions of this file are derived from material licensed 38 * to the University of California by American Telephone and Telegraph 39 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 40 * the permission of UNIX System Laboratories, Inc. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 */ 66 67 /* 68 * External virtual filesystem routines 69 */ 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/kernel.h> 74 #include <sys/malloc.h> 75 #include <sys/mount.h> 76 #include <sys/proc.h> 77 #include <sys/vnode.h> 78 #include <sys/buf.h> 79 #include <sys/eventhandler.h> 80 #include <sys/kthread.h> 81 #include <sys/sysctl.h> 82 83 #include <machine/limits.h> 84 85 #include <sys/buf2.h> 86 #include <sys/thread2.h> 87 #include <sys/sysref2.h> 88 89 #include <vm/vm.h> 90 #include <vm/vm_object.h> 91 92 struct mountscan_info { 93 TAILQ_ENTRY(mountscan_info) msi_entry; 94 int msi_how; 95 struct mount *msi_node; 96 }; 97 98 struct vmntvnodescan_info { 99 TAILQ_ENTRY(vmntvnodescan_info) entry; 100 struct vnode *vp; 101 }; 102 103 struct vnlru_info { 104 int pass; 105 }; 106 107 static int vnlru_nowhere = 0; 108 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RD, 109 &vnlru_nowhere, 0, 110 "Number of times the vnlru process ran without success"); 111 112 113 static struct lwkt_token mntid_token; 114 static struct mount dummymount; 115 116 /* note: mountlist exported to pstat */ 117 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist); 118 static TAILQ_HEAD(,mountscan_info) mountscan_list; 119 static struct lwkt_token mountlist_token; 120 121 static TAILQ_HEAD(,bio_ops) bio_ops_list = TAILQ_HEAD_INITIALIZER(bio_ops_list); 122 123 /* 124 * Called from vfsinit() 125 */ 126 void 127 vfs_mount_init(void) 128 { 129 lwkt_token_init(&mountlist_token, "mntlist"); 130 lwkt_token_init(&mntid_token, "mntid"); 131 TAILQ_INIT(&mountscan_list); 132 mount_init(&dummymount); 133 dummymount.mnt_flag |= MNT_RDONLY; 134 dummymount.mnt_kern_flag |= MNTK_ALL_MPSAFE; 135 } 136 137 /* 138 * Support function called to remove a vnode from the mountlist and 139 * deal with side effects for scans in progress. 140 * 141 * Target mnt_token is held on call. 142 */ 143 static void 144 vremovevnodemnt(struct vnode *vp) 145 { 146 struct vmntvnodescan_info *info; 147 struct mount *mp = vp->v_mount; 148 149 TAILQ_FOREACH(info, &mp->mnt_vnodescan_list, entry) { 150 if (info->vp == vp) 151 info->vp = TAILQ_NEXT(vp, v_nmntvnodes); 152 } 153 TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes); 154 } 155 156 /* 157 * Allocate a new vnode and associate it with a tag, mount point, and 158 * operations vector. 159 * 160 * A VX locked and refd vnode is returned. The caller should setup the 161 * remaining fields and vx_put() or, if he wishes to leave a vref, 162 * vx_unlock() the vnode. 163 */ 164 int 165 getnewvnode(enum vtagtype tag, struct mount *mp, 166 struct vnode **vpp, int lktimeout, int lkflags) 167 { 168 struct vnode *vp; 169 170 KKASSERT(mp != NULL); 171 172 vp = allocvnode(lktimeout, lkflags); 173 vp->v_tag = tag; 174 vp->v_data = NULL; 175 176 /* 177 * By default the vnode is assigned the mount point's normal 178 * operations vector. 179 */ 180 vp->v_ops = &mp->mnt_vn_use_ops; 181 182 /* 183 * Placing the vnode on the mount point's queue makes it visible. 184 * VNON prevents it from being messed with, however. 185 */ 186 insmntque(vp, mp); 187 188 /* 189 * A VX locked & refd vnode is returned. 190 */ 191 *vpp = vp; 192 return (0); 193 } 194 195 /* 196 * This function creates vnodes with special operations vectors. The 197 * mount point is optional. 198 * 199 * This routine is being phased out but is still used by vfs_conf to 200 * create vnodes for devices prior to the root mount (with mp == NULL). 201 */ 202 int 203 getspecialvnode(enum vtagtype tag, struct mount *mp, 204 struct vop_ops **ops, 205 struct vnode **vpp, int lktimeout, int lkflags) 206 { 207 struct vnode *vp; 208 209 vp = allocvnode(lktimeout, lkflags); 210 vp->v_tag = tag; 211 vp->v_data = NULL; 212 vp->v_ops = ops; 213 214 if (mp == NULL) 215 mp = &dummymount; 216 217 /* 218 * Placing the vnode on the mount point's queue makes it visible. 219 * VNON prevents it from being messed with, however. 220 */ 221 insmntque(vp, mp); 222 223 /* 224 * A VX locked & refd vnode is returned. 225 */ 226 *vpp = vp; 227 return (0); 228 } 229 230 /* 231 * Interlock against an unmount, return 0 on success, non-zero on failure. 232 * 233 * The passed flag may be 0 or LK_NOWAIT and is only used if an unmount 234 * is in-progress. 235 * 236 * If no unmount is in-progress LK_NOWAIT is ignored. No other flag bits 237 * are used. A shared locked will be obtained and the filesystem will not 238 * be unmountable until the lock is released. 239 */ 240 int 241 vfs_busy(struct mount *mp, int flags) 242 { 243 int lkflags; 244 245 atomic_add_int(&mp->mnt_refs, 1); 246 lwkt_gettoken(&mp->mnt_token); 247 if (mp->mnt_kern_flag & MNTK_UNMOUNT) { 248 if (flags & LK_NOWAIT) { 249 lwkt_reltoken(&mp->mnt_token); 250 atomic_add_int(&mp->mnt_refs, -1); 251 return (ENOENT); 252 } 253 /* XXX not MP safe */ 254 mp->mnt_kern_flag |= MNTK_MWAIT; 255 /* 256 * Since all busy locks are shared except the exclusive 257 * lock granted when unmounting, the only place that a 258 * wakeup needs to be done is at the release of the 259 * exclusive lock at the end of dounmount. 260 */ 261 tsleep((caddr_t)mp, 0, "vfs_busy", 0); 262 lwkt_reltoken(&mp->mnt_token); 263 atomic_add_int(&mp->mnt_refs, -1); 264 return (ENOENT); 265 } 266 lkflags = LK_SHARED; 267 if (lockmgr(&mp->mnt_lock, lkflags)) 268 panic("vfs_busy: unexpected lock failure"); 269 lwkt_reltoken(&mp->mnt_token); 270 return (0); 271 } 272 273 /* 274 * Free a busy filesystem. 275 * 276 * Decrement refs before releasing the lock so e.g. a pending umount 277 * doesn't give us an unexpected busy error. 278 */ 279 void 280 vfs_unbusy(struct mount *mp) 281 { 282 atomic_add_int(&mp->mnt_refs, -1); 283 lockmgr(&mp->mnt_lock, LK_RELEASE); 284 } 285 286 /* 287 * Lookup a filesystem type, and if found allocate and initialize 288 * a mount structure for it. 289 * 290 * Devname is usually updated by mount(8) after booting. 291 */ 292 int 293 vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp) 294 { 295 struct vfsconf *vfsp; 296 struct mount *mp; 297 298 if (fstypename == NULL) 299 return (ENODEV); 300 301 vfsp = vfsconf_find_by_name(fstypename); 302 if (vfsp == NULL) 303 return (ENODEV); 304 mp = kmalloc(sizeof(struct mount), M_MOUNT, M_WAITOK | M_ZERO); 305 mount_init(mp); 306 lockinit(&mp->mnt_lock, "vfslock", VLKTIMEOUT, 0); 307 308 vfs_busy(mp, 0); 309 mp->mnt_vfc = vfsp; 310 mp->mnt_op = vfsp->vfc_vfsops; 311 vfsp->vfc_refcount++; 312 mp->mnt_stat.f_type = vfsp->vfc_typenum; 313 mp->mnt_flag |= MNT_RDONLY; 314 mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK; 315 strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN); 316 copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0); 317 *mpp = mp; 318 return (0); 319 } 320 321 /* 322 * Basic mount structure initialization 323 */ 324 void 325 mount_init(struct mount *mp) 326 { 327 lockinit(&mp->mnt_lock, "vfslock", hz*5, 0); 328 lwkt_token_init(&mp->mnt_token, "permnt"); 329 330 TAILQ_INIT(&mp->mnt_vnodescan_list); 331 TAILQ_INIT(&mp->mnt_nvnodelist); 332 TAILQ_INIT(&mp->mnt_reservedvnlist); 333 TAILQ_INIT(&mp->mnt_jlist); 334 mp->mnt_nvnodelistsize = 0; 335 mp->mnt_flag = 0; 336 mp->mnt_iosize_max = MAXPHYS; 337 } 338 339 /* 340 * Lookup a mount point by filesystem identifier. 341 */ 342 struct mount * 343 vfs_getvfs(fsid_t *fsid) 344 { 345 struct mount *mp; 346 347 lwkt_gettoken(&mountlist_token); 348 TAILQ_FOREACH(mp, &mountlist, mnt_list) { 349 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] && 350 mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) { 351 break; 352 } 353 } 354 lwkt_reltoken(&mountlist_token); 355 return (mp); 356 } 357 358 /* 359 * Get a new unique fsid. Try to make its val[0] unique, since this value 360 * will be used to create fake device numbers for stat(). Also try (but 361 * not so hard) make its val[0] unique mod 2^16, since some emulators only 362 * support 16-bit device numbers. We end up with unique val[0]'s for the 363 * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls. 364 * 365 * Keep in mind that several mounts may be running in parallel. Starting 366 * the search one past where the previous search terminated is both a 367 * micro-optimization and a defense against returning the same fsid to 368 * different mounts. 369 */ 370 void 371 vfs_getnewfsid(struct mount *mp) 372 { 373 static u_int16_t mntid_base; 374 fsid_t tfsid; 375 int mtype; 376 377 lwkt_gettoken(&mntid_token); 378 mtype = mp->mnt_vfc->vfc_typenum; 379 tfsid.val[1] = mtype; 380 mtype = (mtype & 0xFF) << 24; 381 for (;;) { 382 tfsid.val[0] = makeudev(255, 383 mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF)); 384 mntid_base++; 385 if (vfs_getvfs(&tfsid) == NULL) 386 break; 387 } 388 mp->mnt_stat.f_fsid.val[0] = tfsid.val[0]; 389 mp->mnt_stat.f_fsid.val[1] = tfsid.val[1]; 390 lwkt_reltoken(&mntid_token); 391 } 392 393 /* 394 * Set the FSID for a new mount point to the template. Adjust 395 * the FSID to avoid collisions. 396 */ 397 int 398 vfs_setfsid(struct mount *mp, fsid_t *template) 399 { 400 int didmunge = 0; 401 402 bzero(&mp->mnt_stat.f_fsid, sizeof(mp->mnt_stat.f_fsid)); 403 for (;;) { 404 if (vfs_getvfs(template) == NULL) 405 break; 406 didmunge = 1; 407 ++template->val[1]; 408 } 409 mp->mnt_stat.f_fsid = *template; 410 return(didmunge); 411 } 412 413 /* 414 * This routine is called when we have too many vnodes. It attempts 415 * to free <count> vnodes and will potentially free vnodes that still 416 * have VM backing store (VM backing store is typically the cause 417 * of a vnode blowout so we want to do this). Therefore, this operation 418 * is not considered cheap. 419 * 420 * A number of conditions may prevent a vnode from being reclaimed. 421 * the buffer cache may have references on the vnode, a directory 422 * vnode may still have references due to the namei cache representing 423 * underlying files, or the vnode may be in active use. It is not 424 * desireable to reuse such vnodes. These conditions may cause the 425 * number of vnodes to reach some minimum value regardless of what 426 * you set kern.maxvnodes to. Do not set kern.maxvnodes too low. 427 */ 428 429 /* 430 * This is a quick non-blocking check to determine if the vnode is a good 431 * candidate for being (eventually) vgone()'d. Returns 0 if the vnode is 432 * not a good candidate, 1 if it is. 433 */ 434 static __inline int 435 vmightfree(struct vnode *vp, int page_count, int pass) 436 { 437 if (vp->v_flag & VRECLAIMED) 438 return (0); 439 #if 0 440 if ((vp->v_flag & VFREE) && TAILQ_EMPTY(&vp->v_namecache)) 441 return (0); 442 #endif 443 if (sysref_isactive(&vp->v_sysref)) 444 return (0); 445 if (vp->v_object && vp->v_object->resident_page_count >= page_count) 446 return (0); 447 448 /* 449 * XXX horrible hack. Up to four passes will be taken. Each pass 450 * makes a larger set of vnodes eligible. For now what this really 451 * means is that we try to recycle files opened only once before 452 * recycling files opened multiple times. 453 */ 454 switch(vp->v_flag & (VAGE0 | VAGE1)) { 455 case 0: 456 if (pass < 3) 457 return(0); 458 break; 459 case VAGE0: 460 if (pass < 2) 461 return(0); 462 break; 463 case VAGE1: 464 if (pass < 1) 465 return(0); 466 break; 467 case VAGE0 | VAGE1: 468 break; 469 } 470 return (1); 471 } 472 473 /* 474 * The vnode was found to be possibly vgone()able and the caller has locked it 475 * (thus the usecount should be 1 now). Determine if the vnode is actually 476 * vgone()able, doing some cleanups in the process. Returns 1 if the vnode 477 * can be vgone()'d, 0 otherwise. 478 * 479 * Note that v_auxrefs may be non-zero because (A) this vnode is not a leaf 480 * in the namecache topology and (B) this vnode has buffer cache bufs. 481 * We cannot remove vnodes with non-leaf namecache associations. We do a 482 * tentitive leaf check prior to attempting to flush out any buffers but the 483 * 'real' test when all is said in done is that v_auxrefs must become 0 for 484 * the vnode to be freeable. 485 * 486 * We could theoretically just unconditionally flush when v_auxrefs != 0, 487 * but flushing data associated with non-leaf nodes (which are always 488 * directories), just throws it away for no benefit. It is the buffer 489 * cache's responsibility to choose buffers to recycle from the cached 490 * data point of view. 491 */ 492 static int 493 visleaf(struct vnode *vp) 494 { 495 struct namecache *ncp; 496 497 spin_lock(&vp->v_spin); 498 TAILQ_FOREACH(ncp, &vp->v_namecache, nc_vnode) { 499 if (!TAILQ_EMPTY(&ncp->nc_list)) { 500 spin_unlock(&vp->v_spin); 501 return(0); 502 } 503 } 504 spin_unlock(&vp->v_spin); 505 return(1); 506 } 507 508 /* 509 * Try to clean up the vnode to the point where it can be vgone()'d, returning 510 * 0 if it cannot be vgone()'d (or already has been), 1 if it can. Unlike 511 * vmightfree() this routine may flush the vnode and block. Vnodes marked 512 * VFREE are still candidates for vgone()ing because they may hold namecache 513 * resources and could be blocking the namecache directory hierarchy (and 514 * related vnodes) from being freed. 515 */ 516 static int 517 vtrytomakegoneable(struct vnode *vp, int page_count) 518 { 519 if (vp->v_flag & VRECLAIMED) 520 return (0); 521 if (vp->v_sysref.refcnt > 1) 522 return (0); 523 if (vp->v_object && vp->v_object->resident_page_count >= page_count) 524 return (0); 525 if (vp->v_auxrefs && visleaf(vp)) { 526 vinvalbuf(vp, V_SAVE, 0, 0); 527 #if 0 /* DEBUG */ 528 kprintf((vp->v_auxrefs ? "vrecycle: vp %p failed: %s\n" : 529 "vrecycle: vp %p succeeded: %s\n"), vp, 530 (TAILQ_FIRST(&vp->v_namecache) ? 531 TAILQ_FIRST(&vp->v_namecache)->nc_name : "?")); 532 #endif 533 } 534 535 /* 536 * This sequence may seem a little strange, but we need to optimize 537 * the critical path a bit. We can't recycle vnodes with other 538 * references and because we are trying to recycle an otherwise 539 * perfectly fine vnode we have to invalidate the namecache in a 540 * way that avoids possible deadlocks (since the vnode lock is being 541 * held here). Finally, we have to check for other references one 542 * last time in case something snuck in during the inval. 543 */ 544 if (vp->v_sysref.refcnt > 1 || vp->v_auxrefs != 0) 545 return (0); 546 if (cache_inval_vp_nonblock(vp)) 547 return (0); 548 return (vp->v_sysref.refcnt <= 1 && vp->v_auxrefs == 0); 549 } 550 551 /* 552 * Reclaim up to 1/10 of the vnodes associated with a mount point. Try 553 * to avoid vnodes which have lots of resident pages (we are trying to free 554 * vnodes, not memory). 555 * 556 * This routine is a callback from the mountlist scan. The mount point 557 * in question will be busied. 558 * 559 * NOTE: The 1/10 reclamation also ensures that the inactive data set 560 * (the vnodes being recycled by the one-time use) does not degenerate 561 * into too-small a set. This is important because once a vnode is 562 * marked as not being one-time-use (VAGE0/VAGE1 both 0) that vnode 563 * will not be destroyed EXCEPT by this mechanism. VM pages can still 564 * be cleaned/freed by the pageout daemon. 565 */ 566 static int 567 vlrureclaim(struct mount *mp, void *data) 568 { 569 struct vnlru_info *info = data; 570 struct vnode *vp; 571 int done; 572 int trigger; 573 int usevnodes; 574 int count; 575 int trigger_mult = vnlru_nowhere; 576 577 /* 578 * Calculate the trigger point for the resident pages check. The 579 * minimum trigger value is approximately the number of pages in 580 * the system divded by the number of vnodes. However, due to 581 * various other system memory overheads unrelated to data caching 582 * it is a good idea to double the trigger (at least). 583 * 584 * trigger_mult starts at 0. If the recycler is having problems 585 * finding enough freeable vnodes it will increase trigger_mult. 586 * This should not happen in normal operation, even on machines with 587 * low amounts of memory, but extraordinary memory use by the system 588 * verses the amount of cached data can trigger it. 589 * 590 * (long) -> deal with 64 bit machines, intermediate overflow 591 */ 592 usevnodes = desiredvnodes; 593 if (usevnodes <= 0) 594 usevnodes = 1; 595 trigger = (long)vmstats.v_page_count * (trigger_mult + 2) / usevnodes; 596 597 done = 0; 598 lwkt_gettoken(&mp->mnt_token); 599 count = mp->mnt_nvnodelistsize / 10 + 1; 600 601 while (count && mp->mnt_syncer) { 602 /* 603 * Next vnode. Use the special syncer vnode to placemark 604 * the LRU. This way the LRU code does not interfere with 605 * vmntvnodescan(). 606 */ 607 vp = TAILQ_NEXT(mp->mnt_syncer, v_nmntvnodes); 608 TAILQ_REMOVE(&mp->mnt_nvnodelist, mp->mnt_syncer, v_nmntvnodes); 609 if (vp) { 610 TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, 611 mp->mnt_syncer, v_nmntvnodes); 612 } else { 613 TAILQ_INSERT_HEAD(&mp->mnt_nvnodelist, mp->mnt_syncer, 614 v_nmntvnodes); 615 vp = TAILQ_NEXT(mp->mnt_syncer, v_nmntvnodes); 616 if (vp == NULL) 617 break; 618 } 619 620 /* 621 * __VNODESCAN__ 622 * 623 * The VP will stick around while we hold mnt_token, 624 * at least until we block, so we can safely do an initial 625 * check, and then must check again after we lock the vnode. 626 */ 627 if (vp->v_type == VNON || /* syncer or indeterminant */ 628 !vmightfree(vp, trigger, info->pass) /* critical path opt */ 629 ) { 630 --count; 631 continue; 632 } 633 634 /* 635 * VX get the candidate vnode. If the VX get fails the 636 * vnode might still be on the mountlist. Our loop depends 637 * on us at least cycling the vnode to the end of the 638 * mountlist. 639 */ 640 if (vx_get_nonblock(vp) != 0) { 641 --count; 642 continue; 643 } 644 645 /* 646 * Since we blocked locking the vp, make sure it is still 647 * a candidate for reclamation. That is, it has not already 648 * been reclaimed and only has our VX reference associated 649 * with it. 650 */ 651 if (vp->v_type == VNON || /* syncer or indeterminant */ 652 (vp->v_flag & VRECLAIMED) || 653 vp->v_mount != mp || 654 !vtrytomakegoneable(vp, trigger) /* critical path opt */ 655 ) { 656 --count; 657 vx_put(vp); 658 continue; 659 } 660 661 /* 662 * All right, we are good, move the vp to the end of the 663 * mountlist and clean it out. The vget will have returned 664 * an error if the vnode was destroyed (VRECLAIMED set), so we 665 * do not have to check again. The vput() will move the 666 * vnode to the free list if the vgone() was successful. 667 */ 668 KKASSERT(vp->v_mount == mp); 669 vgone_vxlocked(vp); 670 vx_put(vp); 671 ++done; 672 --count; 673 } 674 lwkt_reltoken(&mp->mnt_token); 675 return (done); 676 } 677 678 /* 679 * Attempt to recycle vnodes in a context that is always safe to block. 680 * Calling vlrurecycle() from the bowels of file system code has some 681 * interesting deadlock problems. 682 */ 683 static struct thread *vnlruthread; 684 685 static void 686 vnlru_proc(void) 687 { 688 struct thread *td = curthread; 689 struct vnlru_info info; 690 int done; 691 692 EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc, td, 693 SHUTDOWN_PRI_FIRST); 694 695 for (;;) { 696 kproc_suspend_loop(); 697 698 /* 699 * Do some opportunistic roving. 700 */ 701 if (numvnodes > 100000) 702 vnode_free_rover_scan(50); 703 else if (numvnodes > 10000) 704 vnode_free_rover_scan(20); 705 else 706 vnode_free_rover_scan(5); 707 708 /* 709 * Try to free some vnodes if we have too many 710 * 711 * (long) -> deal with 64 bit machines, intermediate overflow 712 */ 713 if (numvnodes > desiredvnodes && 714 freevnodes > desiredvnodes * 2 / 10) { 715 int count = numvnodes - desiredvnodes; 716 717 if (count > freevnodes / 100) 718 count = freevnodes / 100; 719 if (count < 5) 720 count = 5; 721 freesomevnodes(count); 722 } 723 724 /* 725 * Do non-critical-path (more robust) cache cleaning, 726 * even if vnode counts are nominal, to try to avoid 727 * having to do it in the critical path. 728 */ 729 cache_hysteresis(0); 730 731 /* 732 * Nothing to do if most of our vnodes are already on 733 * the free list. 734 */ 735 if (numvnodes - freevnodes <= (long)desiredvnodes * 9 / 10) { 736 tsleep(vnlruthread, 0, "vlruwt", hz); 737 continue; 738 } 739 740 /* 741 * The pass iterates through the four combinations of 742 * VAGE0/VAGE1. We want to get rid of aged small files 743 * first. 744 */ 745 info.pass = 0; 746 done = 0; 747 while (done == 0 && info.pass < 4) { 748 done = mountlist_scan(vlrureclaim, &info, 749 MNTSCAN_FORWARD); 750 ++info.pass; 751 } 752 753 /* 754 * The vlrureclaim() call only processes 1/10 of the vnodes 755 * on each mount. If we couldn't find any repeat the loop 756 * at least enough times to cover all available vnodes before 757 * we start sleeping. Complain if the failure extends past 758 * 30 second, every 30 seconds. 759 */ 760 if (done == 0) { 761 ++vnlru_nowhere; 762 if (vnlru_nowhere % 10 == 0) 763 tsleep(vnlruthread, 0, "vlrup", hz * 3); 764 if (vnlru_nowhere % 100 == 0) 765 kprintf("vnlru_proc: vnode recycler stopped working!\n"); 766 if (vnlru_nowhere == 1000) 767 vnlru_nowhere = 900; 768 } else { 769 vnlru_nowhere = 0; 770 } 771 } 772 } 773 774 /* 775 * MOUNTLIST FUNCTIONS 776 */ 777 778 /* 779 * mountlist_insert (MP SAFE) 780 * 781 * Add a new mount point to the mount list. 782 */ 783 void 784 mountlist_insert(struct mount *mp, int how) 785 { 786 lwkt_gettoken(&mountlist_token); 787 if (how == MNTINS_FIRST) 788 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list); 789 else 790 TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); 791 lwkt_reltoken(&mountlist_token); 792 } 793 794 /* 795 * mountlist_interlock (MP SAFE) 796 * 797 * Execute the specified interlock function with the mountlist token 798 * held. The function will be called in a serialized fashion verses 799 * other functions called through this mechanism. 800 */ 801 int 802 mountlist_interlock(int (*callback)(struct mount *), struct mount *mp) 803 { 804 int error; 805 806 lwkt_gettoken(&mountlist_token); 807 error = callback(mp); 808 lwkt_reltoken(&mountlist_token); 809 return (error); 810 } 811 812 /* 813 * mountlist_boot_getfirst (DURING BOOT ONLY) 814 * 815 * This function returns the first mount on the mountlist, which is 816 * expected to be the root mount. Since no interlocks are obtained 817 * this function is only safe to use during booting. 818 */ 819 820 struct mount * 821 mountlist_boot_getfirst(void) 822 { 823 return(TAILQ_FIRST(&mountlist)); 824 } 825 826 /* 827 * mountlist_remove (MP SAFE) 828 * 829 * Remove a node from the mountlist. If this node is the next scan node 830 * for any active mountlist scans, the active mountlist scan will be 831 * adjusted to skip the node, thus allowing removals during mountlist 832 * scans. 833 */ 834 void 835 mountlist_remove(struct mount *mp) 836 { 837 struct mountscan_info *msi; 838 839 lwkt_gettoken(&mountlist_token); 840 TAILQ_FOREACH(msi, &mountscan_list, msi_entry) { 841 if (msi->msi_node == mp) { 842 if (msi->msi_how & MNTSCAN_FORWARD) 843 msi->msi_node = TAILQ_NEXT(mp, mnt_list); 844 else 845 msi->msi_node = TAILQ_PREV(mp, mntlist, mnt_list); 846 } 847 } 848 TAILQ_REMOVE(&mountlist, mp, mnt_list); 849 lwkt_reltoken(&mountlist_token); 850 } 851 852 /* 853 * mountlist_exists (MP SAFE) 854 * 855 * Checks if a node exists in the mountlist. 856 * This function is mainly used by VFS quota code to check if a 857 * cached nullfs struct mount pointer is still valid at use time 858 * 859 * FIXME: there is no warranty the mp passed to that function 860 * will be the same one used by VFS_ACCOUNT() later 861 */ 862 int 863 mountlist_exists(struct mount *mp) 864 { 865 int node_exists = 0; 866 struct mount* lmp; 867 868 lwkt_gettoken(&mountlist_token); 869 TAILQ_FOREACH(lmp, &mountlist, mnt_list) { 870 if (lmp == mp) { 871 node_exists = 1; 872 break; 873 } 874 } 875 lwkt_reltoken(&mountlist_token); 876 return(node_exists); 877 } 878 879 /* 880 * mountlist_scan (MP SAFE) 881 * 882 * Safely scan the mount points on the mount list. Unless otherwise 883 * specified each mount point will be busied prior to the callback and 884 * unbusied afterwords. The callback may safely remove any mount point 885 * without interfering with the scan. If the current callback 886 * mount is removed the scanner will not attempt to unbusy it. 887 * 888 * If a mount node cannot be busied it is silently skipped. 889 * 890 * The callback return value is aggregated and a total is returned. A return 891 * value of < 0 is not aggregated and will terminate the scan. 892 * 893 * MNTSCAN_FORWARD - the mountlist is scanned in the forward direction 894 * MNTSCAN_REVERSE - the mountlist is scanned in reverse 895 * MNTSCAN_NOBUSY - the scanner will make the callback without busying 896 * the mount node. 897 */ 898 int 899 mountlist_scan(int (*callback)(struct mount *, void *), void *data, int how) 900 { 901 struct mountscan_info info; 902 struct mount *mp; 903 int count; 904 int res; 905 906 lwkt_gettoken(&mountlist_token); 907 908 info.msi_how = how; 909 info.msi_node = NULL; /* paranoia */ 910 TAILQ_INSERT_TAIL(&mountscan_list, &info, msi_entry); 911 912 res = 0; 913 914 if (how & MNTSCAN_FORWARD) { 915 info.msi_node = TAILQ_FIRST(&mountlist); 916 while ((mp = info.msi_node) != NULL) { 917 if (how & MNTSCAN_NOBUSY) { 918 count = callback(mp, data); 919 } else if (vfs_busy(mp, LK_NOWAIT) == 0) { 920 count = callback(mp, data); 921 if (mp == info.msi_node) 922 vfs_unbusy(mp); 923 } else { 924 count = 0; 925 } 926 if (count < 0) 927 break; 928 res += count; 929 if (mp == info.msi_node) 930 info.msi_node = TAILQ_NEXT(mp, mnt_list); 931 } 932 } else if (how & MNTSCAN_REVERSE) { 933 info.msi_node = TAILQ_LAST(&mountlist, mntlist); 934 while ((mp = info.msi_node) != NULL) { 935 if (how & MNTSCAN_NOBUSY) { 936 count = callback(mp, data); 937 } else if (vfs_busy(mp, LK_NOWAIT) == 0) { 938 count = callback(mp, data); 939 if (mp == info.msi_node) 940 vfs_unbusy(mp); 941 } else { 942 count = 0; 943 } 944 if (count < 0) 945 break; 946 res += count; 947 if (mp == info.msi_node) 948 info.msi_node = TAILQ_PREV(mp, mntlist, mnt_list); 949 } 950 } 951 TAILQ_REMOVE(&mountscan_list, &info, msi_entry); 952 lwkt_reltoken(&mountlist_token); 953 return(res); 954 } 955 956 /* 957 * MOUNT RELATED VNODE FUNCTIONS 958 */ 959 960 static struct kproc_desc vnlru_kp = { 961 "vnlru", 962 vnlru_proc, 963 &vnlruthread 964 }; 965 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp) 966 967 /* 968 * Move a vnode from one mount queue to another. 969 * 970 * MPSAFE 971 */ 972 void 973 insmntque(struct vnode *vp, struct mount *mp) 974 { 975 struct mount *omp; 976 977 /* 978 * Delete from old mount point vnode list, if on one. 979 */ 980 if ((omp = vp->v_mount) != NULL) { 981 lwkt_gettoken(&omp->mnt_token); 982 KKASSERT(omp == vp->v_mount); 983 KASSERT(omp->mnt_nvnodelistsize > 0, 984 ("bad mount point vnode list size")); 985 vremovevnodemnt(vp); 986 omp->mnt_nvnodelistsize--; 987 lwkt_reltoken(&omp->mnt_token); 988 } 989 990 /* 991 * Insert into list of vnodes for the new mount point, if available. 992 * The 'end' of the LRU list is the vnode prior to mp->mnt_syncer. 993 */ 994 if (mp == NULL) { 995 vp->v_mount = NULL; 996 return; 997 } 998 lwkt_gettoken(&mp->mnt_token); 999 vp->v_mount = mp; 1000 if (mp->mnt_syncer) { 1001 TAILQ_INSERT_BEFORE(mp->mnt_syncer, vp, v_nmntvnodes); 1002 } else { 1003 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes); 1004 } 1005 mp->mnt_nvnodelistsize++; 1006 lwkt_reltoken(&mp->mnt_token); 1007 } 1008 1009 1010 /* 1011 * Scan the vnodes under a mount point and issue appropriate callbacks. 1012 * 1013 * The fastfunc() callback is called with just the mountlist token held 1014 * (no vnode lock). It may not block and the vnode may be undergoing 1015 * modifications while the caller is processing it. The vnode will 1016 * not be entirely destroyed, however, due to the fact that the mountlist 1017 * token is held. A return value < 0 skips to the next vnode without calling 1018 * the slowfunc(), a return value > 0 terminates the loop. 1019 * 1020 * The slowfunc() callback is called after the vnode has been successfully 1021 * locked based on passed flags. The vnode is skipped if it gets rearranged 1022 * or destroyed while blocking on the lock. A non-zero return value from 1023 * the slow function terminates the loop. The slow function is allowed to 1024 * arbitrarily block. The scanning code guarentees consistency of operation 1025 * even if the slow function deletes or moves the node, or blocks and some 1026 * other thread deletes or moves the node. 1027 * 1028 * NOTE: We hold vmobj_token to prevent a VM object from being destroyed 1029 * out from under the fastfunc()'s vnode test. It will not prevent 1030 * v_object from getting NULL'd out but it will ensure that the 1031 * pointer (if we race) will remain stable. 1032 */ 1033 int 1034 vmntvnodescan( 1035 struct mount *mp, 1036 int flags, 1037 int (*fastfunc)(struct mount *mp, struct vnode *vp, void *data), 1038 int (*slowfunc)(struct mount *mp, struct vnode *vp, void *data), 1039 void *data 1040 ) { 1041 struct vmntvnodescan_info info; 1042 struct vnode *vp; 1043 int r = 0; 1044 int maxcount = mp->mnt_nvnodelistsize * 2; 1045 int stopcount = 0; 1046 int count = 0; 1047 1048 lwkt_gettoken(&mp->mnt_token); 1049 lwkt_gettoken(&vmobj_token); 1050 1051 /* 1052 * If asked to do one pass stop after iterating available vnodes. 1053 * Under heavy loads new vnodes can be added while we are scanning, 1054 * so this isn't perfect. Create a slop factor of 2x. 1055 */ 1056 if (flags & VMSC_ONEPASS) 1057 stopcount = mp->mnt_nvnodelistsize; 1058 1059 info.vp = TAILQ_FIRST(&mp->mnt_nvnodelist); 1060 TAILQ_INSERT_TAIL(&mp->mnt_vnodescan_list, &info, entry); 1061 1062 while ((vp = info.vp) != NULL) { 1063 if (--maxcount == 0) { 1064 kprintf("Warning: excessive fssync iteration\n"); 1065 maxcount = mp->mnt_nvnodelistsize * 2; 1066 } 1067 1068 /* 1069 * Skip if visible but not ready, or special (e.g. 1070 * mp->mnt_syncer) 1071 */ 1072 if (vp->v_type == VNON) 1073 goto next; 1074 KKASSERT(vp->v_mount == mp); 1075 1076 /* 1077 * Quick test. A negative return continues the loop without 1078 * calling the slow test. 0 continues onto the slow test. 1079 * A positive number aborts the loop. 1080 */ 1081 if (fastfunc) { 1082 if ((r = fastfunc(mp, vp, data)) < 0) { 1083 r = 0; 1084 goto next; 1085 } 1086 if (r) 1087 break; 1088 } 1089 1090 /* 1091 * Get a vxlock on the vnode, retry if it has moved or isn't 1092 * in the mountlist where we expect it. 1093 */ 1094 if (slowfunc) { 1095 int error; 1096 1097 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) { 1098 case VMSC_GETVP: 1099 error = vget(vp, LK_EXCLUSIVE); 1100 break; 1101 case VMSC_GETVP|VMSC_NOWAIT: 1102 error = vget(vp, LK_EXCLUSIVE|LK_NOWAIT); 1103 break; 1104 case VMSC_GETVX: 1105 vx_get(vp); 1106 error = 0; 1107 break; 1108 default: 1109 error = 0; 1110 break; 1111 } 1112 if (error) 1113 goto next; 1114 /* 1115 * Do not call the slow function if the vnode is 1116 * invalid or if it was ripped out from under us 1117 * while we (potentially) blocked. 1118 */ 1119 if (info.vp == vp && vp->v_type != VNON) 1120 r = slowfunc(mp, vp, data); 1121 1122 /* 1123 * Cleanup 1124 */ 1125 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) { 1126 case VMSC_GETVP: 1127 case VMSC_GETVP|VMSC_NOWAIT: 1128 vput(vp); 1129 break; 1130 case VMSC_GETVX: 1131 vx_put(vp); 1132 break; 1133 default: 1134 break; 1135 } 1136 if (r != 0) 1137 break; 1138 } 1139 1140 next: 1141 /* 1142 * Yield after some processing. Depending on the number 1143 * of vnodes, we might wind up running for a long time. 1144 * Because threads are not preemptable, time critical 1145 * userland processes might starve. Give them a chance 1146 * now and then. 1147 */ 1148 if (++count == 10000) { 1149 /* We really want to yield a bit, so we simply sleep a tick */ 1150 tsleep(mp, 0, "vnodescn", 1); 1151 count = 0; 1152 } 1153 1154 /* 1155 * If doing one pass this decrements to zero. If it starts 1156 * at zero it is effectively unlimited for the purposes of 1157 * this loop. 1158 */ 1159 if (--stopcount == 0) 1160 break; 1161 1162 /* 1163 * Iterate. If the vnode was ripped out from under us 1164 * info.vp will already point to the next vnode, otherwise 1165 * we have to obtain the next valid vnode ourselves. 1166 */ 1167 if (info.vp == vp) 1168 info.vp = TAILQ_NEXT(vp, v_nmntvnodes); 1169 } 1170 1171 TAILQ_REMOVE(&mp->mnt_vnodescan_list, &info, entry); 1172 lwkt_reltoken(&vmobj_token); 1173 lwkt_reltoken(&mp->mnt_token); 1174 return(r); 1175 } 1176 1177 /* 1178 * Remove any vnodes in the vnode table belonging to mount point mp. 1179 * 1180 * If FORCECLOSE is not specified, there should not be any active ones, 1181 * return error if any are found (nb: this is a user error, not a 1182 * system error). If FORCECLOSE is specified, detach any active vnodes 1183 * that are found. 1184 * 1185 * If WRITECLOSE is set, only flush out regular file vnodes open for 1186 * writing. 1187 * 1188 * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped. 1189 * 1190 * `rootrefs' specifies the base reference count for the root vnode 1191 * of this filesystem. The root vnode is considered busy if its 1192 * v_sysref.refcnt exceeds this value. On a successful return, vflush() 1193 * will call vrele() on the root vnode exactly rootrefs times. 1194 * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must 1195 * be zero. 1196 */ 1197 #ifdef DIAGNOSTIC 1198 static int busyprt = 0; /* print out busy vnodes */ 1199 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, ""); 1200 #endif 1201 1202 static int vflush_scan(struct mount *mp, struct vnode *vp, void *data); 1203 1204 struct vflush_info { 1205 int flags; 1206 int busy; 1207 thread_t td; 1208 }; 1209 1210 int 1211 vflush(struct mount *mp, int rootrefs, int flags) 1212 { 1213 struct thread *td = curthread; /* XXX */ 1214 struct vnode *rootvp = NULL; 1215 int error; 1216 struct vflush_info vflush_info; 1217 1218 if (rootrefs > 0) { 1219 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0, 1220 ("vflush: bad args")); 1221 /* 1222 * Get the filesystem root vnode. We can vput() it 1223 * immediately, since with rootrefs > 0, it won't go away. 1224 */ 1225 if ((error = VFS_ROOT(mp, &rootvp)) != 0) { 1226 if ((flags & FORCECLOSE) == 0) 1227 return (error); 1228 rootrefs = 0; 1229 /* continue anyway */ 1230 } 1231 if (rootrefs) 1232 vput(rootvp); 1233 } 1234 1235 vflush_info.busy = 0; 1236 vflush_info.flags = flags; 1237 vflush_info.td = td; 1238 vmntvnodescan(mp, VMSC_GETVX, NULL, vflush_scan, &vflush_info); 1239 1240 if (rootrefs > 0 && (flags & FORCECLOSE) == 0) { 1241 /* 1242 * If just the root vnode is busy, and if its refcount 1243 * is equal to `rootrefs', then go ahead and kill it. 1244 */ 1245 KASSERT(vflush_info.busy > 0, ("vflush: not busy")); 1246 KASSERT(rootvp->v_sysref.refcnt >= rootrefs, ("vflush: rootrefs")); 1247 if (vflush_info.busy == 1 && rootvp->v_sysref.refcnt == rootrefs) { 1248 vx_lock(rootvp); 1249 vgone_vxlocked(rootvp); 1250 vx_unlock(rootvp); 1251 vflush_info.busy = 0; 1252 } 1253 } 1254 if (vflush_info.busy) 1255 return (EBUSY); 1256 for (; rootrefs > 0; rootrefs--) 1257 vrele(rootvp); 1258 return (0); 1259 } 1260 1261 /* 1262 * The scan callback is made with an VX locked vnode. 1263 */ 1264 static int 1265 vflush_scan(struct mount *mp, struct vnode *vp, void *data) 1266 { 1267 struct vflush_info *info = data; 1268 struct vattr vattr; 1269 int flags = info->flags; 1270 1271 /* 1272 * Skip over a vnodes marked VSYSTEM. 1273 */ 1274 if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) { 1275 return(0); 1276 } 1277 1278 /* 1279 * Do not force-close VCHR or VBLK vnodes 1280 */ 1281 if (vp->v_type == VCHR || vp->v_type == VBLK) 1282 flags &= ~(WRITECLOSE|FORCECLOSE); 1283 1284 /* 1285 * If WRITECLOSE is set, flush out unlinked but still open 1286 * files (even if open only for reading) and regular file 1287 * vnodes open for writing. 1288 */ 1289 if ((flags & WRITECLOSE) && 1290 (vp->v_type == VNON || 1291 (VOP_GETATTR(vp, &vattr) == 0 && 1292 vattr.va_nlink > 0)) && 1293 (vp->v_writecount == 0 || vp->v_type != VREG)) { 1294 return(0); 1295 } 1296 1297 /* 1298 * If we are the only holder (refcnt of 1) or the vnode is in 1299 * termination (refcnt < 0), we can vgone the vnode. 1300 */ 1301 if (vp->v_sysref.refcnt <= 1) { 1302 vgone_vxlocked(vp); 1303 return(0); 1304 } 1305 1306 /* 1307 * If FORCECLOSE is set, forcibly destroy the vnode and then move 1308 * it to a dummymount structure so vop_*() functions don't deref 1309 * a NULL pointer. 1310 */ 1311 if (flags & FORCECLOSE) { 1312 vhold(vp); 1313 vgone_vxlocked(vp); 1314 if (vp->v_mount == NULL) 1315 insmntque(vp, &dummymount); 1316 vdrop(vp); 1317 return(0); 1318 } 1319 if (vp->v_type == VCHR || vp->v_type == VBLK) 1320 kprintf("vflush: Warning, cannot destroy busy device vnode\n"); 1321 #ifdef DIAGNOSTIC 1322 if (busyprt) 1323 vprint("vflush: busy vnode", vp); 1324 #endif 1325 ++info->busy; 1326 return(0); 1327 } 1328 1329 void 1330 add_bio_ops(struct bio_ops *ops) 1331 { 1332 TAILQ_INSERT_TAIL(&bio_ops_list, ops, entry); 1333 } 1334 1335 void 1336 rem_bio_ops(struct bio_ops *ops) 1337 { 1338 TAILQ_REMOVE(&bio_ops_list, ops, entry); 1339 } 1340 1341 /* 1342 * This calls the bio_ops io_sync function either for a mount point 1343 * or generally. 1344 * 1345 * WARNING: softdeps is weirdly coded and just isn't happy unless 1346 * io_sync is called with a NULL mount from the general syncing code. 1347 */ 1348 void 1349 bio_ops_sync(struct mount *mp) 1350 { 1351 struct bio_ops *ops; 1352 1353 if (mp) { 1354 if ((ops = mp->mnt_bioops) != NULL) 1355 ops->io_sync(mp); 1356 } else { 1357 TAILQ_FOREACH(ops, &bio_ops_list, entry) { 1358 ops->io_sync(NULL); 1359 } 1360 } 1361 } 1362 1363 /* 1364 * Lookup a mount point by nch 1365 */ 1366 struct mount * 1367 mount_get_by_nc(struct namecache *ncp) 1368 { 1369 struct mount *mp = NULL; 1370 1371 lwkt_gettoken(&mountlist_token); 1372 TAILQ_FOREACH(mp, &mountlist, mnt_list) { 1373 if (ncp == mp->mnt_ncmountpt.ncp) 1374 break; 1375 } 1376 lwkt_reltoken(&mountlist_token); 1377 return (mp); 1378 } 1379 1380