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. All advertising materials mentioning features or use of this software 51 * must display the following acknowledgement: 52 * This product includes software developed by the University of 53 * California, Berkeley and its contributors. 54 * 4. Neither the name of the University nor the names of its contributors 55 * may be used to endorse or promote products derived from this software 56 * without specific prior written permission. 57 * 58 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 59 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 60 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 61 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 62 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 63 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 64 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 65 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 66 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 67 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 68 * SUCH DAMAGE. 69 * 70 * $DragonFly: src/sys/kern/vfs_mount.c,v 1.2 2004/10/19 05:55:34 dillon Exp $ 71 */ 72 73 /* 74 * External virtual filesystem routines 75 */ 76 #include "opt_ddb.h" 77 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/kernel.h> 81 #include <sys/malloc.h> 82 #include <sys/mount.h> 83 #include <sys/proc.h> 84 #include <sys/vnode.h> 85 #include <sys/buf.h> 86 #include <sys/eventhandler.h> 87 #include <sys/kthread.h> 88 #include <sys/sysctl.h> 89 90 #include <machine/limits.h> 91 92 #include <sys/buf2.h> 93 #include <sys/thread2.h> 94 95 #include <vm/vm.h> 96 #include <vm/vm_object.h> 97 98 static int vnlru_nowhere = 0; 99 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW, 100 &vnlru_nowhere, 0, 101 "Number of times the vnlru process ran without success"); 102 103 104 static struct lwkt_token mntid_token; 105 106 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist); /* mounted fs */ 107 struct lwkt_token mountlist_token; 108 struct lwkt_token mntvnode_token; 109 110 111 /* 112 * Called from vfsinit() 113 */ 114 void 115 vfs_mount_init(void) 116 { 117 lwkt_token_init(&mountlist_token); 118 lwkt_token_init(&mntvnode_token); 119 lwkt_token_init(&mntid_token); 120 } 121 122 /* 123 * Allocate a new vnode and associate it with a tag, mount point, and 124 * operations vector. 125 * 126 * A VX locked and refd vnode is returned. The caller should setup the 127 * remaining fields and vx_put() or, if he wishes to leave a vref, 128 * vx_unlock() the vnode. 129 */ 130 int 131 getnewvnode(enum vtagtype tag, struct mount *mp, struct vop_ops *ops, 132 struct vnode **vpp, int lktimeout, int lkflags) 133 { 134 struct vnode *vp; 135 136 vp = allocvnode(lktimeout, lkflags); 137 vp->v_tag = tag; 138 vp->v_ops = ops; 139 vp->v_data = NULL; 140 141 /* 142 * Placing the vnode on the mount point's queue makes it visible. 143 * VNON prevents it from being messed with, however. 144 */ 145 insmntque(vp, mp); 146 vfs_object_create(vp, curthread); 147 148 /* 149 * A VX locked & refd vnode is returned. 150 */ 151 *vpp = vp; 152 return (0); 153 } 154 155 /* 156 * Mark a mount point as busy. Used to synchronize access and to delay 157 * unmounting. Interlock is not released on failure. 158 */ 159 int 160 vfs_busy(struct mount *mp, int flags, 161 lwkt_tokref_t interlkp, struct thread *td) 162 { 163 int lkflags; 164 165 if (mp->mnt_kern_flag & MNTK_UNMOUNT) { 166 if (flags & LK_NOWAIT) 167 return (ENOENT); 168 mp->mnt_kern_flag |= MNTK_MWAIT; 169 /* 170 * Since all busy locks are shared except the exclusive 171 * lock granted when unmounting, the only place that a 172 * wakeup needs to be done is at the release of the 173 * exclusive lock at the end of dounmount. 174 * 175 * note: interlkp is a serializer and thus can be safely 176 * held through any sleep 177 */ 178 tsleep((caddr_t)mp, 0, "vfs_busy", 0); 179 return (ENOENT); 180 } 181 lkflags = LK_SHARED | LK_NOPAUSE; 182 if (interlkp) 183 lkflags |= LK_INTERLOCK; 184 if (lockmgr(&mp->mnt_lock, lkflags, interlkp, td)) 185 panic("vfs_busy: unexpected lock failure"); 186 return (0); 187 } 188 189 /* 190 * Free a busy filesystem. 191 */ 192 void 193 vfs_unbusy(struct mount *mp, struct thread *td) 194 { 195 lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td); 196 } 197 198 /* 199 * Lookup a filesystem type, and if found allocate and initialize 200 * a mount structure for it. 201 * 202 * Devname is usually updated by mount(8) after booting. 203 */ 204 int 205 vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp) 206 { 207 struct thread *td = curthread; /* XXX */ 208 struct vfsconf *vfsp; 209 struct mount *mp; 210 211 if (fstypename == NULL) 212 return (ENODEV); 213 for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) { 214 if (!strcmp(vfsp->vfc_name, fstypename)) 215 break; 216 } 217 if (vfsp == NULL) 218 return (ENODEV); 219 mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK); 220 bzero((char *)mp, (u_long)sizeof(struct mount)); 221 lockinit(&mp->mnt_lock, 0, "vfslock", VLKTIMEOUT, LK_NOPAUSE); 222 vfs_busy(mp, LK_NOWAIT, NULL, td); 223 TAILQ_INIT(&mp->mnt_nvnodelist); 224 TAILQ_INIT(&mp->mnt_reservedvnlist); 225 mp->mnt_nvnodelistsize = 0; 226 mp->mnt_vfc = vfsp; 227 mp->mnt_op = vfsp->vfc_vfsops; 228 mp->mnt_flag = MNT_RDONLY; 229 mp->mnt_vnodecovered = NULLVP; 230 vfsp->vfc_refcount++; 231 mp->mnt_iosize_max = DFLTPHYS; 232 mp->mnt_stat.f_type = vfsp->vfc_typenum; 233 mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK; 234 strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN); 235 mp->mnt_stat.f_mntonname[0] = '/'; 236 mp->mnt_stat.f_mntonname[1] = 0; 237 (void) copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0); 238 *mpp = mp; 239 return (0); 240 } 241 242 /* 243 * Lookup a mount point by filesystem identifier. 244 */ 245 struct mount * 246 vfs_getvfs(fsid_t *fsid) 247 { 248 struct mount *mp; 249 lwkt_tokref ilock; 250 251 lwkt_gettoken(&ilock, &mountlist_token); 252 TAILQ_FOREACH(mp, &mountlist, mnt_list) { 253 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] && 254 mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) { 255 break; 256 } 257 } 258 lwkt_reltoken(&ilock); 259 return (mp); 260 } 261 262 /* 263 * Get a new unique fsid. Try to make its val[0] unique, since this value 264 * will be used to create fake device numbers for stat(). Also try (but 265 * not so hard) make its val[0] unique mod 2^16, since some emulators only 266 * support 16-bit device numbers. We end up with unique val[0]'s for the 267 * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls. 268 * 269 * Keep in mind that several mounts may be running in parallel. Starting 270 * the search one past where the previous search terminated is both a 271 * micro-optimization and a defense against returning the same fsid to 272 * different mounts. 273 */ 274 void 275 vfs_getnewfsid(struct mount *mp) 276 { 277 static u_int16_t mntid_base; 278 lwkt_tokref ilock; 279 fsid_t tfsid; 280 int mtype; 281 282 lwkt_gettoken(&ilock, &mntid_token); 283 mtype = mp->mnt_vfc->vfc_typenum; 284 tfsid.val[1] = mtype; 285 mtype = (mtype & 0xFF) << 24; 286 for (;;) { 287 tfsid.val[0] = makeudev(255, 288 mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF)); 289 mntid_base++; 290 if (vfs_getvfs(&tfsid) == NULL) 291 break; 292 } 293 mp->mnt_stat.f_fsid.val[0] = tfsid.val[0]; 294 mp->mnt_stat.f_fsid.val[1] = tfsid.val[1]; 295 lwkt_reltoken(&ilock); 296 } 297 298 /* 299 * This routine is called when we have too many vnodes. It attempts 300 * to free <count> vnodes and will potentially free vnodes that still 301 * have VM backing store (VM backing store is typically the cause 302 * of a vnode blowout so we want to do this). Therefore, this operation 303 * is not considered cheap. 304 * 305 * A number of conditions may prevent a vnode from being reclaimed. 306 * the buffer cache may have references on the vnode, a directory 307 * vnode may still have references due to the namei cache representing 308 * underlying files, or the vnode may be in active use. It is not 309 * desireable to reuse such vnodes. These conditions may cause the 310 * number of vnodes to reach some minimum value regardless of what 311 * you set kern.maxvnodes to. Do not set kern.maxvnodes too low. 312 */ 313 314 /* 315 * Return 0 if the vnode is not already on the free list, return 1 if the 316 * vnode, with some additional work could possibly be placed on the free list. 317 */ 318 static __inline int 319 vmightfree(struct vnode *vp, int use_count, int page_count) 320 { 321 if (vp->v_flag & VFREE) 322 return (0); 323 if (vp->v_usecount != use_count || vp->v_holdcnt) 324 return (0); 325 if (vp->v_object && vp->v_object->resident_page_count >= page_count) 326 return (0); 327 return (1); 328 } 329 330 331 static int 332 vlrureclaim(struct mount *mp) 333 { 334 struct vnode *vp; 335 lwkt_tokref ilock; 336 int done; 337 int trigger; 338 int usevnodes; 339 int count; 340 341 /* 342 * Calculate the trigger point, don't allow user 343 * screwups to blow us up. This prevents us from 344 * recycling vnodes with lots of resident pages. We 345 * aren't trying to free memory, we are trying to 346 * free vnodes. 347 */ 348 usevnodes = desiredvnodes; 349 if (usevnodes <= 0) 350 usevnodes = 1; 351 trigger = vmstats.v_page_count * 2 / usevnodes; 352 353 done = 0; 354 lwkt_gettoken(&ilock, &mntvnode_token); 355 count = mp->mnt_nvnodelistsize / 10 + 1; 356 while (count && (vp = TAILQ_FIRST(&mp->mnt_nvnodelist)) != NULL) { 357 /* 358 * __VNODESCAN__ 359 * 360 * The VP will stick around while we hold mntvnode_token, 361 * at least until we block, so we can safely do an initial 362 * check, and then must check again after we lock the vnode. 363 */ 364 if (vp->v_type == VNON || /* XXX */ 365 vp->v_type == VBAD || /* XXX */ 366 !vmightfree(vp, 0, trigger) /* critical path opt */ 367 ) { 368 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes); 369 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist,vp, v_nmntvnodes); 370 --count; 371 continue; 372 } 373 374 /* 375 * VX get the candidate vnode. If the VX get fails the 376 * vnode might still be on the mountlist. Our loop depends 377 * on us at least cycling the vnode to the end of the 378 * mountlist. 379 */ 380 if (vx_get_nonblock(vp) != 0) { 381 if (vp->v_mount == mp) { 382 TAILQ_REMOVE(&mp->mnt_nvnodelist, 383 vp, v_nmntvnodes); 384 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, 385 vp, v_nmntvnodes); 386 } 387 --count; 388 continue; 389 } 390 391 /* 392 * Since we blocked locking the vp, make sure it is still 393 * a candidate for reclamation. That is, it has not already 394 * been reclaimed and only has our VX reference associated 395 * with it. 396 */ 397 if (vp->v_type == VNON || /* XXX */ 398 vp->v_type == VBAD || /* XXX */ 399 (vp->v_flag & VRECLAIMED) || 400 vp->v_mount != mp || 401 !vmightfree(vp, 1, trigger) /* critical path opt */ 402 ) { 403 if (vp->v_mount == mp) { 404 TAILQ_REMOVE(&mp->mnt_nvnodelist, 405 vp, v_nmntvnodes); 406 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, 407 vp, v_nmntvnodes); 408 } 409 --count; 410 vx_put(vp); 411 continue; 412 } 413 414 /* 415 * All right, we are good, move the vp to the end of the 416 * mountlist and clean it out. The vget will have returned 417 * an error if the vnode was destroyed (VRECLAIMED set), so we 418 * do not have to check again. The vput() will move the 419 * vnode to the free list if the vgone() was successful. 420 */ 421 KKASSERT(vp->v_mount == mp); 422 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes); 423 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist,vp, v_nmntvnodes); 424 vgone(vp); 425 vx_put(vp); 426 ++done; 427 --count; 428 } 429 lwkt_reltoken(&ilock); 430 return (done); 431 } 432 433 /* 434 * Attempt to recycle vnodes in a context that is always safe to block. 435 * Calling vlrurecycle() from the bowels of file system code has some 436 * interesting deadlock problems. 437 */ 438 static struct thread *vnlruthread; 439 static int vnlruproc_sig; 440 441 void 442 vnlru_proc_wait(void) 443 { 444 if (vnlruproc_sig == 0) { 445 vnlruproc_sig = 1; /* avoid unnecessary wakeups */ 446 wakeup(vnlruthread); 447 } 448 tsleep(&vnlruproc_sig, 0, "vlruwk", hz); 449 } 450 451 static void 452 vnlru_proc(void) 453 { 454 struct mount *mp, *nmp; 455 lwkt_tokref ilock; 456 int s; 457 int done; 458 struct thread *td = curthread; 459 460 EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc, td, 461 SHUTDOWN_PRI_FIRST); 462 463 s = splbio(); 464 for (;;) { 465 kproc_suspend_loop(); 466 if (numvnodes - freevnodes <= desiredvnodes * 9 / 10) { 467 vnlruproc_sig = 0; 468 wakeup(&vnlruproc_sig); 469 tsleep(td, 0, "vlruwt", hz); 470 continue; 471 } 472 done = 0; 473 cache_cleanneg(0); 474 lwkt_gettoken(&ilock, &mountlist_token); 475 for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) { 476 if (vfs_busy(mp, LK_NOWAIT, &ilock, td)) { 477 nmp = TAILQ_NEXT(mp, mnt_list); 478 continue; 479 } 480 done += vlrureclaim(mp); 481 lwkt_gettokref(&ilock); 482 nmp = TAILQ_NEXT(mp, mnt_list); 483 vfs_unbusy(mp, td); 484 } 485 lwkt_reltoken(&ilock); 486 if (done == 0) { 487 ++vnlru_nowhere; 488 tsleep(td, 0, "vlrup", hz * 3); 489 if (vnlru_nowhere % 10 == 0) 490 printf("vnlru_proc: vnode recycler stopped working!\n"); 491 } else { 492 vnlru_nowhere = 0; 493 } 494 } 495 splx(s); 496 } 497 498 static struct kproc_desc vnlru_kp = { 499 "vnlru", 500 vnlru_proc, 501 &vnlruthread 502 }; 503 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp) 504 505 /* 506 * Move a vnode from one mount queue to another. 507 */ 508 void 509 insmntque(struct vnode *vp, struct mount *mp) 510 { 511 lwkt_tokref ilock; 512 513 lwkt_gettoken(&ilock, &mntvnode_token); 514 /* 515 * Delete from old mount point vnode list, if on one. 516 */ 517 if (vp->v_mount != NULL) { 518 KASSERT(vp->v_mount->mnt_nvnodelistsize > 0, 519 ("bad mount point vnode list size")); 520 TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes); 521 vp->v_mount->mnt_nvnodelistsize--; 522 } 523 /* 524 * Insert into list of vnodes for the new mount point, if available. 525 */ 526 if ((vp->v_mount = mp) == NULL) { 527 lwkt_reltoken(&ilock); 528 return; 529 } 530 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes); 531 mp->mnt_nvnodelistsize++; 532 lwkt_reltoken(&ilock); 533 } 534 535 536 /* 537 * Scan the vnodes under a mount point. The first function is called 538 * with just the mountlist token held (no vnode lock). The second 539 * function is called with the vnode VX locked. 540 */ 541 int 542 vmntvnodescan( 543 struct mount *mp, 544 int flags, 545 int (*fastfunc)(struct mount *mp, struct vnode *vp, void *data), 546 int (*slowfunc)(struct mount *mp, struct vnode *vp, void *data), 547 void *data 548 ) { 549 lwkt_tokref ilock; 550 struct vnode *pvp; 551 struct vnode *vp; 552 int r = 0; 553 554 /* 555 * Scan the vnodes on the mount's vnode list. Use a placemarker 556 */ 557 pvp = allocvnode_placemarker(); 558 559 lwkt_gettoken(&ilock, &mntvnode_token); 560 TAILQ_INSERT_HEAD(&mp->mnt_nvnodelist, pvp, v_nmntvnodes); 561 562 while ((vp = TAILQ_NEXT(pvp, v_nmntvnodes)) != NULL) { 563 /* 564 * Move the placemarker and skip other placemarkers we 565 * encounter. The nothing can get in our way so the 566 * mount point on the vp must be valid. 567 */ 568 TAILQ_REMOVE(&mp->mnt_nvnodelist, pvp, v_nmntvnodes); 569 TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, pvp, v_nmntvnodes); 570 if (vp->v_flag & VPLACEMARKER) /* another procs placemarker */ 571 continue; 572 if (vp->v_type == VNON) /* visible but not ready */ 573 continue; 574 KKASSERT(vp->v_mount == mp); 575 576 /* 577 * Quick test. A negative return continues the loop without 578 * calling the slow test. 0 continues onto the slow test. 579 * A positive number aborts the loop. 580 */ 581 if (fastfunc) { 582 if ((r = fastfunc(mp, vp, data)) < 0) 583 continue; 584 if (r) 585 break; 586 } 587 588 /* 589 * Get a vxlock on the vnode, retry if it has moved or isn't 590 * in the mountlist where we expect it. 591 */ 592 if (slowfunc) { 593 int error; 594 595 switch(flags) { 596 case VMSC_GETVP: 597 error = vget(vp, LK_EXCLUSIVE, curthread); 598 break; 599 case VMSC_GETVP|VMSC_NOWAIT: 600 error = vget(vp, LK_EXCLUSIVE|LK_NOWAIT, 601 curthread); 602 break; 603 case VMSC_GETVX: 604 error = vx_get(vp); 605 break; 606 case VMSC_REFVP: 607 vref(vp); 608 /* fall through */ 609 default: 610 error = 0; 611 break; 612 } 613 if (error) 614 continue; 615 if (TAILQ_PREV(pvp, vnodelst, v_nmntvnodes) != vp) 616 goto skip; 617 if (vp->v_type == VNON) 618 goto skip; 619 r = slowfunc(mp, vp, data); 620 skip: 621 switch(flags) { 622 case VMSC_GETVP: 623 case VMSC_GETVP|VMSC_NOWAIT: 624 vput(vp); 625 break; 626 case VMSC_GETVX: 627 vx_put(vp); 628 break; 629 case VMSC_REFVP: 630 vrele(vp); 631 /* fall through */ 632 default: 633 break; 634 } 635 if (r != 0) 636 break; 637 } 638 } 639 TAILQ_REMOVE(&mp->mnt_nvnodelist, pvp, v_nmntvnodes); 640 freevnode_placemarker(pvp); 641 lwkt_reltoken(&ilock); 642 return(r); 643 } 644 645 /* 646 * Remove any vnodes in the vnode table belonging to mount point mp. 647 * 648 * If FORCECLOSE is not specified, there should not be any active ones, 649 * return error if any are found (nb: this is a user error, not a 650 * system error). If FORCECLOSE is specified, detach any active vnodes 651 * that are found. 652 * 653 * If WRITECLOSE is set, only flush out regular file vnodes open for 654 * writing. 655 * 656 * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped. 657 * 658 * `rootrefs' specifies the base reference count for the root vnode 659 * of this filesystem. The root vnode is considered busy if its 660 * v_usecount exceeds this value. On a successful return, vflush() 661 * will call vrele() on the root vnode exactly rootrefs times. 662 * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must 663 * be zero. 664 */ 665 #ifdef DIAGNOSTIC 666 static int busyprt = 0; /* print out busy vnodes */ 667 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, ""); 668 #endif 669 670 static int vflush_scan(struct mount *mp, struct vnode *vp, void *data); 671 672 struct vflush_info { 673 int flags; 674 int busy; 675 thread_t td; 676 }; 677 678 int 679 vflush(struct mount *mp, int rootrefs, int flags) 680 { 681 struct thread *td = curthread; /* XXX */ 682 struct vnode *rootvp = NULL; 683 int error; 684 struct vflush_info vflush_info; 685 686 if (rootrefs > 0) { 687 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0, 688 ("vflush: bad args")); 689 /* 690 * Get the filesystem root vnode. We can vput() it 691 * immediately, since with rootrefs > 0, it won't go away. 692 */ 693 if ((error = VFS_ROOT(mp, &rootvp)) != 0) 694 return (error); 695 vput(rootvp); 696 } 697 698 vflush_info.busy = 0; 699 vflush_info.flags = flags; 700 vflush_info.td = td; 701 vmntvnodescan(mp, VMSC_GETVX, NULL, vflush_scan, &vflush_info); 702 703 if (rootrefs > 0 && (flags & FORCECLOSE) == 0) { 704 /* 705 * If just the root vnode is busy, and if its refcount 706 * is equal to `rootrefs', then go ahead and kill it. 707 */ 708 KASSERT(vflush_info.busy > 0, ("vflush: not busy")); 709 KASSERT(rootvp->v_usecount >= rootrefs, ("vflush: rootrefs")); 710 if (vflush_info.busy == 1 && rootvp->v_usecount == rootrefs) { 711 if (vx_lock(rootvp) == 0) { 712 vgone(rootvp); 713 vx_unlock(rootvp); 714 vflush_info.busy = 0; 715 } 716 } 717 } 718 if (vflush_info.busy) 719 return (EBUSY); 720 for (; rootrefs > 0; rootrefs--) 721 vrele(rootvp); 722 return (0); 723 } 724 725 /* 726 * The scan callback is made with an VX locked vnode. 727 */ 728 static int 729 vflush_scan(struct mount *mp, struct vnode *vp, void *data) 730 { 731 struct vflush_info *info = data; 732 struct vattr vattr; 733 734 /* 735 * Skip over a vnodes marked VSYSTEM. 736 */ 737 if ((info->flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) { 738 return(0); 739 } 740 741 /* 742 * If WRITECLOSE is set, flush out unlinked but still open 743 * files (even if open only for reading) and regular file 744 * vnodes open for writing. 745 */ 746 if ((info->flags & WRITECLOSE) && 747 (vp->v_type == VNON || 748 (VOP_GETATTR(vp, &vattr, info->td) == 0 && 749 vattr.va_nlink > 0)) && 750 (vp->v_writecount == 0 || vp->v_type != VREG)) { 751 return(0); 752 } 753 754 /* 755 * With v_usecount == 0, all we need to do is clear out the 756 * vnode data structures and we are done. 757 */ 758 if (vp->v_usecount == 1) { 759 vgone(vp); 760 return(0); 761 } 762 763 /* 764 * If FORCECLOSE is set, forcibly close the vnode. For block 765 * or character devices, revert to an anonymous device. For 766 * all other files, just kill them. 767 */ 768 if (info->flags & FORCECLOSE) { 769 if (vp->v_type != VBLK && vp->v_type != VCHR) { 770 vgone(vp); 771 } else { 772 vclean(vp, 0, info->td); 773 vp->v_ops = spec_vnode_vops; 774 insmntque(vp, NULL); 775 } 776 return(0); 777 } 778 #ifdef DIAGNOSTIC 779 if (busyprt) 780 vprint("vflush: busy vnode", vp); 781 #endif 782 ++info->busy; 783 return(0); 784 } 785 786