1 /* 2 * Copyright (c) 2004,2013-2019 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/spinlock2.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 <vm/vm.h> 86 #include <vm/vm_object.h> 87 88 struct mountscan_info { 89 TAILQ_ENTRY(mountscan_info) msi_entry; 90 int msi_how; 91 struct mount *msi_node; 92 }; 93 94 struct vmntvnodescan_info { 95 TAILQ_ENTRY(vmntvnodescan_info) entry; 96 struct vnode *vp; 97 }; 98 99 static int 100 mount_cmp(struct mount *mnt1, struct mount *mnt2) 101 { 102 if (mnt1->mnt_stat.f_fsid.val[0] < mnt2->mnt_stat.f_fsid.val[0]) 103 return -1; 104 if (mnt1->mnt_stat.f_fsid.val[0] > mnt2->mnt_stat.f_fsid.val[0]) 105 return 1; 106 if (mnt1->mnt_stat.f_fsid.val[1] < mnt2->mnt_stat.f_fsid.val[1]) 107 return -1; 108 if (mnt1->mnt_stat.f_fsid.val[1] > mnt2->mnt_stat.f_fsid.val[1]) 109 return 1; 110 return 0; 111 } 112 113 static int 114 mount_fsid_cmp(fsid_t *fsid, struct mount *mnt) 115 { 116 if (fsid->val[0] < mnt->mnt_stat.f_fsid.val[0]) 117 return -1; 118 if (fsid->val[0] > mnt->mnt_stat.f_fsid.val[0]) 119 return 1; 120 if (fsid->val[1] < mnt->mnt_stat.f_fsid.val[1]) 121 return -1; 122 if (fsid->val[1] > mnt->mnt_stat.f_fsid.val[1]) 123 return 1; 124 return 0; 125 } 126 127 RB_HEAD(mount_rb_tree, mount); 128 RB_PROTOTYPEX(mount_rb_tree, FSID, mount, mnt_node, mount_cmp, fsid_t *); 129 RB_GENERATE(mount_rb_tree, mount, mnt_node, mount_cmp); 130 RB_GENERATE_XLOOKUP(mount_rb_tree, FSID, mount, mnt_node, 131 mount_fsid_cmp, fsid_t *); 132 133 static int vnlru_nowhere = 0; 134 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RD, 135 &vnlru_nowhere, 0, 136 "Number of times the vnlru process ran without success"); 137 138 139 static struct lwkt_token mntid_token; 140 static struct mount dummymount; 141 142 /* note: mountlist exported to pstat */ 143 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist); 144 struct mount_rb_tree mounttree = RB_INITIALIZER(dev_tree_mounttree); 145 static TAILQ_HEAD(,mountscan_info) mountscan_list; 146 static struct lwkt_token mountlist_token; 147 148 static TAILQ_HEAD(,bio_ops) bio_ops_list = TAILQ_HEAD_INITIALIZER(bio_ops_list); 149 150 /* 151 * Called from vfsinit() 152 */ 153 void 154 vfs_mount_init(void) 155 { 156 lwkt_token_init(&mountlist_token, "mntlist"); 157 lwkt_token_init(&mntid_token, "mntid"); 158 TAILQ_INIT(&mountscan_list); 159 mount_init(&dummymount, NULL); 160 dummymount.mnt_flag |= MNT_RDONLY; 161 dummymount.mnt_kern_flag |= MNTK_ALL_MPSAFE; 162 } 163 164 /* 165 * Support function called to remove a vnode from the mountlist and 166 * deal with side effects for scans in progress. 167 * 168 * Target mnt_token is held on call. 169 */ 170 static void 171 vremovevnodemnt(struct vnode *vp) 172 { 173 struct vmntvnodescan_info *info; 174 struct mount *mp = vp->v_mount; 175 176 TAILQ_FOREACH(info, &mp->mnt_vnodescan_list, entry) { 177 if (info->vp == vp) 178 info->vp = TAILQ_NEXT(vp, v_nmntvnodes); 179 } 180 TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes); 181 } 182 183 /* 184 * Allocate a new vnode and associate it with a tag, mount point, and 185 * operations vector. 186 * 187 * A VX locked and refd vnode is returned. The caller should setup the 188 * remaining fields and vx_put() or, if he wishes to leave a vref, 189 * vx_unlock() the vnode. Or if he wishes to return a normal locked 190 * vnode, call vx_downgrade(vp); to downgrade the VX lock to a normal 191 * VN lock. 192 */ 193 int 194 getnewvnode(enum vtagtype tag, struct mount *mp, 195 struct vnode **vpp, int lktimeout, int lkflags) 196 { 197 struct vnode *vp; 198 199 KKASSERT(mp != NULL); 200 201 vp = allocvnode(lktimeout, lkflags); 202 vp->v_tag = tag; 203 vp->v_data = NULL; 204 205 /* 206 * By default the vnode is assigned the mount point's normal 207 * operations vector. 208 */ 209 vp->v_ops = &mp->mnt_vn_use_ops; 210 vp->v_pbuf_count = nswbuf_kva / NSWBUF_SPLIT; 211 212 /* 213 * Placing the vnode on the mount point's queue makes it visible. 214 * VNON prevents it from being messed with, however. 215 */ 216 insmntque(vp, mp); 217 218 /* 219 * A VX locked & refd vnode is returned. 220 */ 221 *vpp = vp; 222 return (0); 223 } 224 225 /* 226 * This function creates vnodes with special operations vectors. The 227 * mount point is optional. 228 * 229 * This routine is being phased out but is still used by vfs_conf to 230 * create vnodes for devices prior to the root mount (with mp == NULL). 231 */ 232 int 233 getspecialvnode(enum vtagtype tag, struct mount *mp, 234 struct vop_ops **ops, 235 struct vnode **vpp, int lktimeout, int lkflags) 236 { 237 struct vnode *vp; 238 239 vp = allocvnode(lktimeout, lkflags); 240 vp->v_tag = tag; 241 vp->v_data = NULL; 242 vp->v_ops = ops; 243 244 if (mp == NULL) 245 mp = &dummymount; 246 247 /* 248 * Placing the vnode on the mount point's queue makes it visible. 249 * VNON prevents it from being messed with, however. 250 */ 251 insmntque(vp, mp); 252 253 /* 254 * A VX locked & refd vnode is returned. 255 */ 256 *vpp = vp; 257 return (0); 258 } 259 260 /* 261 * Interlock against an unmount, return 0 on success, non-zero on failure. 262 * 263 * The passed flag may be 0 or LK_NOWAIT and is only used if an unmount 264 * is in-progress. 265 * 266 * If no unmount is in-progress LK_NOWAIT is ignored. No other flag bits 267 * are used. A shared locked will be obtained and the filesystem will not 268 * be unmountable until the lock is released. 269 */ 270 int 271 vfs_busy(struct mount *mp, int flags) 272 { 273 int lkflags; 274 275 atomic_add_int(&mp->mnt_refs, 1); 276 lwkt_gettoken(&mp->mnt_token); 277 if (mp->mnt_kern_flag & MNTK_UNMOUNT) { 278 if (flags & LK_NOWAIT) { 279 lwkt_reltoken(&mp->mnt_token); 280 atomic_add_int(&mp->mnt_refs, -1); 281 return (ENOENT); 282 } 283 /* XXX not MP safe */ 284 mp->mnt_kern_flag |= MNTK_MWAIT; 285 286 /* 287 * Since all busy locks are shared except the exclusive 288 * lock granted when unmounting, the only place that a 289 * wakeup needs to be done is at the release of the 290 * exclusive lock at the end of dounmount. 291 * 292 * WARNING! mp can potentially go away once we release 293 * our ref. 294 */ 295 tsleep((caddr_t)mp, 0, "vfs_busy", 0); 296 lwkt_reltoken(&mp->mnt_token); 297 atomic_add_int(&mp->mnt_refs, -1); 298 return (ENOENT); 299 } 300 lkflags = LK_SHARED; 301 if (lockmgr(&mp->mnt_lock, lkflags)) 302 panic("vfs_busy: unexpected lock failure"); 303 lwkt_reltoken(&mp->mnt_token); 304 return (0); 305 } 306 307 /* 308 * Free a busy filesystem. 309 * 310 * Once refs is decremented the mount point can potentially get ripped 311 * out from under us, but we want to clean up our refs before unlocking 312 * so do a hold/drop around the whole mess. 313 * 314 * This is not in the critical path (I hope). 315 */ 316 void 317 vfs_unbusy(struct mount *mp) 318 { 319 mount_hold(mp); 320 atomic_add_int(&mp->mnt_refs, -1); 321 lockmgr(&mp->mnt_lock, LK_RELEASE); 322 mount_drop(mp); 323 } 324 325 /* 326 * Lookup a filesystem type, and if found allocate and initialize 327 * a mount structure for it. 328 * 329 * Devname is usually updated by mount(8) after booting. 330 */ 331 int 332 vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp) 333 { 334 struct vfsconf *vfsp; 335 struct mount *mp; 336 337 if (fstypename == NULL) 338 return (ENODEV); 339 340 vfsp = vfsconf_find_by_name(fstypename); 341 if (vfsp == NULL) 342 return (ENODEV); 343 mp = kmalloc(sizeof(struct mount), M_MOUNT, M_WAITOK | M_ZERO); 344 mount_init(mp, vfsp->vfc_vfsops); 345 lockinit(&mp->mnt_lock, "vfslock", VLKTIMEOUT, 0); 346 lockinit(&mp->mnt_renlock, "renamlk", VLKTIMEOUT, 0); 347 348 vfs_busy(mp, 0); 349 mp->mnt_vfc = vfsp; 350 mp->mnt_pbuf_count = nswbuf_kva / NSWBUF_SPLIT; 351 vfsp->vfc_refcount++; 352 mp->mnt_stat.f_type = vfsp->vfc_typenum; 353 mp->mnt_flag |= MNT_RDONLY; 354 mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK; 355 strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN); 356 copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0); 357 358 /* 359 * Pre-set MPSAFE flags for VFS_MOUNT() call. 360 */ 361 if (vfsp->vfc_flags & VFCF_MPSAFE) 362 mp->mnt_kern_flag |= MNTK_ALL_MPSAFE; 363 364 *mpp = mp; 365 366 return (0); 367 } 368 369 /* 370 * Basic mount structure initialization 371 */ 372 void 373 mount_init(struct mount *mp, struct vfsops *ops) 374 { 375 lockinit(&mp->mnt_lock, "vfslock", hz*5, 0); 376 lockinit(&mp->mnt_renlock, "renamlk", hz*5, 0); 377 lwkt_token_init(&mp->mnt_token, "permnt"); 378 379 TAILQ_INIT(&mp->mnt_vnodescan_list); 380 TAILQ_INIT(&mp->mnt_nvnodelist); 381 TAILQ_INIT(&mp->mnt_reservedvnlist); 382 TAILQ_INIT(&mp->mnt_jlist); 383 mp->mnt_nvnodelistsize = 0; 384 mp->mnt_flag = 0; 385 mp->mnt_hold = 1; /* hold for umount last drop */ 386 mp->mnt_iosize_max = MAXPHYS; 387 mp->mnt_op = ops; 388 if (ops == NULL || (ops->vfs_flags & VFSOPSF_NOSYNCERTHR) == 0) 389 vn_syncer_thr_create(mp); 390 } 391 392 void 393 mount_hold(struct mount *mp) 394 { 395 atomic_add_int(&mp->mnt_hold, 1); 396 } 397 398 void 399 mount_drop(struct mount *mp) 400 { 401 if (atomic_fetchadd_int(&mp->mnt_hold, -1) == 1) { 402 KKASSERT(mp->mnt_refs == 0); 403 kfree(mp, M_MOUNT); 404 } 405 } 406 407 /* 408 * Lookup a mount point by filesystem identifier. 409 * 410 * If not NULL, the returned mp is held and the caller is expected to drop 411 * it via mount_drop(). 412 */ 413 struct mount * 414 vfs_getvfs(fsid_t *fsid) 415 { 416 struct mount *mp; 417 418 lwkt_gettoken_shared(&mountlist_token); 419 mp = mount_rb_tree_RB_LOOKUP_FSID(&mounttree, fsid); 420 if (mp) 421 mount_hold(mp); 422 lwkt_reltoken(&mountlist_token); 423 return (mp); 424 } 425 426 /* 427 * Generate a FSID based on the mountpt. The FSID will be adjusted to avoid 428 * collisions when the mount is added to mountlist. 429 * 430 * May only be called prior to the mount succeeding. 431 * 432 * OLD: 433 * 434 * Get a new unique fsid. Try to make its val[0] unique, since this value 435 * will be used to create fake device numbers for stat(). Also try (but 436 * not so hard) make its val[0] unique mod 2^16, since some emulators only 437 * support 16-bit device numbers. We end up with unique val[0]'s for the 438 * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls. 439 */ 440 void 441 vfs_getnewfsid(struct mount *mp) 442 { 443 fsid_t tfsid; 444 int mtype; 445 int error; 446 char *retbuf; 447 char *freebuf; 448 449 mtype = mp->mnt_vfc->vfc_typenum; 450 tfsid.val[1] = mtype; 451 error = cache_fullpath(NULL, &mp->mnt_ncmounton, NULL, 452 &retbuf, &freebuf, 0); 453 if (error) { 454 tfsid.val[0] = makeudev(255, 0); 455 } else { 456 tfsid.val[0] = makeudev(255, 457 iscsi_crc32(retbuf, strlen(retbuf)) & 458 ~makeudev(255, 0)); 459 /*kprintf("getnewfsid %08x %08x %s\n", tfsid.val[0], tfsid.val[1], retbuf);*/ 460 kfree(freebuf, M_TEMP); 461 } 462 mp->mnt_stat.f_fsid.val[0] = tfsid.val[0]; 463 mp->mnt_stat.f_fsid.val[1] = tfsid.val[1]; 464 } 465 466 /* 467 * Set the FSID for a new mount point to the template. 468 * 469 * The FSID will be adjusted to avoid collisions when the mount is 470 * added to mountlist. 471 * 472 * May only be called prior to the mount succeeding. 473 */ 474 void 475 vfs_setfsid(struct mount *mp, fsid_t *template) 476 { 477 bzero(&mp->mnt_stat.f_fsid, sizeof(mp->mnt_stat.f_fsid)); 478 479 #if 0 480 struct mount *mptmp; 481 482 lwkt_gettoken(&mntid_token); 483 for (;;) { 484 mptmp = vfs_getvfs(template); 485 if (mptmp == NULL) 486 break; 487 mount_drop(mptmp); 488 ++template->val[1]; 489 } 490 lwkt_reltoken(&mntid_token); 491 #endif 492 mp->mnt_stat.f_fsid = *template; 493 } 494 495 /* 496 * This routine is called when we have too many vnodes. It attempts 497 * to free <count> vnodes and will potentially free vnodes that still 498 * have VM backing store (VM backing store is typically the cause 499 * of a vnode blowout so we want to do this). Therefore, this operation 500 * is not considered cheap. 501 * 502 * A number of conditions may prevent a vnode from being reclaimed. 503 * the buffer cache may have references on the vnode, a directory 504 * vnode may still have references due to the namei cache representing 505 * underlying files, or the vnode may be in active use. It is not 506 * desireable to reuse such vnodes. These conditions may cause the 507 * number of vnodes to reach some minimum value regardless of what 508 * you set kern.maxvnodes to. Do not set kern.maxvnodes too low. 509 */ 510 511 /* 512 * Attempt to recycle vnodes in a context that is always safe to block. 513 * Calling vlrurecycle() from the bowels of file system code has some 514 * interesting deadlock problems. 515 */ 516 static struct thread *vnlruthread; 517 518 static void 519 vnlru_proc(void) 520 { 521 struct thread *td = curthread; 522 523 EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc, td, 524 SHUTDOWN_PRI_FIRST); 525 526 for (;;) { 527 int ncachedandinactive; 528 529 kproc_suspend_loop(); 530 531 /* 532 * Try to free some vnodes if we have too many. Trigger based 533 * on potentially freeable vnodes but calculate the count 534 * based on total vnodes. 535 * 536 * (long) -> deal with 64 bit machines, intermediate overflow 537 */ 538 synchronizevnodecount(); 539 ncachedandinactive = countcachedandinactivevnodes(); 540 if (numvnodes >= maxvnodes * 9 / 10 && 541 ncachedandinactive >= maxvnodes * 5 / 10) { 542 int count = numvnodes - maxvnodes * 9 / 10; 543 544 if (count > (ncachedandinactive) / 100) 545 count = (ncachedandinactive) / 100; 546 if (count < 5) 547 count = 5; 548 freesomevnodes(count); 549 } 550 551 /* 552 * Do non-critical-path (more robust) cache cleaning, 553 * even if vnode counts are nominal, to try to avoid 554 * having to do it in the critical path. 555 */ 556 cache_hysteresis(0); 557 558 /* 559 * Nothing to do if most of our vnodes are already on 560 * the free list. 561 */ 562 synchronizevnodecount(); 563 ncachedandinactive = countcachedandinactivevnodes(); 564 if (numvnodes <= maxvnodes * 9 / 10 || 565 ncachedandinactive <= maxvnodes * 5 / 10) { 566 tsleep(vnlruthread, 0, "vlruwt", hz); 567 continue; 568 } 569 } 570 } 571 572 /* 573 * MOUNTLIST FUNCTIONS 574 */ 575 576 /* 577 * mountlist_insert (MP SAFE) 578 * 579 * Add a new mount point to the mount list. Filesystem should attempt to 580 * supply a unique fsid but if a duplicate occurs adjust the fsid to ensure 581 * uniqueness. 582 */ 583 void 584 mountlist_insert(struct mount *mp, int how) 585 { 586 int lim = 0x01000000; 587 588 lwkt_gettoken(&mountlist_token); 589 if (how == MNTINS_FIRST) 590 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list); 591 else 592 TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); 593 while (mount_rb_tree_RB_INSERT(&mounttree, mp)) { 594 int32_t val; 595 596 /* 597 * minor device mask: 0xFFFF00FF 598 */ 599 val = mp->mnt_stat.f_fsid.val[0]; 600 val = ((val & 0xFFFF0000) >> 8) | (val & 0x000000FF); 601 ++val; 602 val = ((val << 8) & 0xFFFF0000) | (val & 0x000000FF); 603 mp->mnt_stat.f_fsid.val[0] = val; 604 if (--lim == 0) { 605 lim = 0x01000000; 606 mp->mnt_stat.f_fsid.val[1] += 0x0100; 607 kprintf("mountlist_insert: fsid collision, " 608 "too many mounts\n"); 609 } 610 } 611 lwkt_reltoken(&mountlist_token); 612 } 613 614 /* 615 * mountlist_interlock (MP SAFE) 616 * 617 * Execute the specified interlock function with the mountlist token 618 * held. The function will be called in a serialized fashion verses 619 * other functions called through this mechanism. 620 * 621 * The function is expected to be very short-lived. 622 */ 623 int 624 mountlist_interlock(int (*callback)(struct mount *), struct mount *mp) 625 { 626 int error; 627 628 lwkt_gettoken(&mountlist_token); 629 error = callback(mp); 630 lwkt_reltoken(&mountlist_token); 631 return (error); 632 } 633 634 /* 635 * mountlist_boot_getfirst (DURING BOOT ONLY) 636 * 637 * This function returns the first mount on the mountlist, which is 638 * expected to be the root mount. Since no interlocks are obtained 639 * this function is only safe to use during booting. 640 */ 641 642 struct mount * 643 mountlist_boot_getfirst(void) 644 { 645 return(TAILQ_FIRST(&mountlist)); 646 } 647 648 /* 649 * mountlist_remove (MP SAFE) 650 * 651 * Remove a node from the mountlist. If this node is the next scan node 652 * for any active mountlist scans, the active mountlist scan will be 653 * adjusted to skip the node, thus allowing removals during mountlist 654 * scans. 655 */ 656 void 657 mountlist_remove(struct mount *mp) 658 { 659 struct mountscan_info *msi; 660 661 lwkt_gettoken(&mountlist_token); 662 TAILQ_FOREACH(msi, &mountscan_list, msi_entry) { 663 if (msi->msi_node == mp) { 664 if (msi->msi_how & MNTSCAN_FORWARD) 665 msi->msi_node = TAILQ_NEXT(mp, mnt_list); 666 else 667 msi->msi_node = TAILQ_PREV(mp, mntlist, 668 mnt_list); 669 } 670 } 671 TAILQ_REMOVE(&mountlist, mp, mnt_list); 672 mount_rb_tree_RB_REMOVE(&mounttree, mp); 673 lwkt_reltoken(&mountlist_token); 674 } 675 676 /* 677 * mountlist_exists (MP SAFE) 678 * 679 * Checks if a node exists in the mountlist. 680 * This function is mainly used by VFS quota code to check if a 681 * cached nullfs struct mount pointer is still valid at use time 682 * 683 * FIXME: there is no warranty the mp passed to that function 684 * will be the same one used by VFS_ACCOUNT() later 685 */ 686 int 687 mountlist_exists(struct mount *mp) 688 { 689 int node_exists = 0; 690 struct mount* lmp; 691 692 lwkt_gettoken_shared(&mountlist_token); 693 TAILQ_FOREACH(lmp, &mountlist, mnt_list) { 694 if (lmp == mp) { 695 node_exists = 1; 696 break; 697 } 698 } 699 lwkt_reltoken(&mountlist_token); 700 701 return(node_exists); 702 } 703 704 /* 705 * mountlist_scan 706 * 707 * Safely scan the mount points on the mount list. Each mountpoint 708 * is held across the callback. The callback is responsible for 709 * acquiring any further tokens or locks. 710 * 711 * Unless otherwise specified each mount point will be busied prior to the 712 * callback and unbusied afterwords. The callback may safely remove any 713 * mount point without interfering with the scan. If the current callback 714 * mount is removed the scanner will not attempt to unbusy it. 715 * 716 * If a mount node cannot be busied it is silently skipped. 717 * 718 * The callback return value is aggregated and a total is returned. A return 719 * value of < 0 is not aggregated and will terminate the scan. 720 * 721 * MNTSCAN_FORWARD - the mountlist is scanned in the forward direction 722 * MNTSCAN_REVERSE - the mountlist is scanned in reverse 723 * MNTSCAN_NOBUSY - the scanner will make the callback without busying 724 * the mount node. 725 * MNTSCAN_NOUNLOCK - Do not unlock mountlist_token across callback 726 * 727 * NOTE: mountlist_token is not held across the callback. 728 */ 729 int 730 mountlist_scan(int (*callback)(struct mount *, void *), void *data, int how) 731 { 732 struct mountscan_info info; 733 struct mount *mp; 734 int count; 735 int res; 736 int dounlock = ((how & MNTSCAN_NOUNLOCK) == 0); 737 738 lwkt_gettoken(&mountlist_token); 739 info.msi_how = how; 740 info.msi_node = NULL; /* paranoia */ 741 TAILQ_INSERT_TAIL(&mountscan_list, &info, msi_entry); 742 lwkt_reltoken(&mountlist_token); 743 744 res = 0; 745 lwkt_gettoken_shared(&mountlist_token); 746 747 if (how & MNTSCAN_FORWARD) { 748 info.msi_node = TAILQ_FIRST(&mountlist); 749 while ((mp = info.msi_node) != NULL) { 750 mount_hold(mp); 751 if (how & MNTSCAN_NOBUSY) { 752 if (dounlock) 753 lwkt_reltoken(&mountlist_token); 754 count = callback(mp, data); 755 if (dounlock) 756 lwkt_gettoken_shared(&mountlist_token); 757 } else if (vfs_busy(mp, LK_NOWAIT) == 0) { 758 if (dounlock) 759 lwkt_reltoken(&mountlist_token); 760 count = callback(mp, data); 761 if (dounlock) 762 lwkt_gettoken_shared(&mountlist_token); 763 if (mp == info.msi_node) 764 vfs_unbusy(mp); 765 } else { 766 count = 0; 767 } 768 mount_drop(mp); 769 if (count < 0) 770 break; 771 res += count; 772 if (mp == info.msi_node) 773 info.msi_node = TAILQ_NEXT(mp, mnt_list); 774 } 775 } else if (how & MNTSCAN_REVERSE) { 776 info.msi_node = TAILQ_LAST(&mountlist, mntlist); 777 while ((mp = info.msi_node) != NULL) { 778 mount_hold(mp); 779 if (how & MNTSCAN_NOBUSY) { 780 if (dounlock) 781 lwkt_reltoken(&mountlist_token); 782 count = callback(mp, data); 783 if (dounlock) 784 lwkt_gettoken_shared(&mountlist_token); 785 } else if (vfs_busy(mp, LK_NOWAIT) == 0) { 786 if (dounlock) 787 lwkt_reltoken(&mountlist_token); 788 count = callback(mp, data); 789 if (dounlock) 790 lwkt_gettoken_shared(&mountlist_token); 791 if (mp == info.msi_node) 792 vfs_unbusy(mp); 793 } else { 794 count = 0; 795 } 796 mount_drop(mp); 797 if (count < 0) 798 break; 799 res += count; 800 if (mp == info.msi_node) 801 info.msi_node = TAILQ_PREV(mp, mntlist, 802 mnt_list); 803 } 804 } 805 lwkt_reltoken(&mountlist_token); 806 807 lwkt_gettoken(&mountlist_token); 808 TAILQ_REMOVE(&mountscan_list, &info, msi_entry); 809 lwkt_reltoken(&mountlist_token); 810 811 return(res); 812 } 813 814 /* 815 * MOUNT RELATED VNODE FUNCTIONS 816 */ 817 818 static struct kproc_desc vnlru_kp = { 819 "vnlru", 820 vnlru_proc, 821 &vnlruthread 822 }; 823 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp); 824 825 /* 826 * Move a vnode from one mount queue to another. 827 */ 828 void 829 insmntque(struct vnode *vp, struct mount *mp) 830 { 831 struct mount *omp; 832 833 /* 834 * Delete from old mount point vnode list, if on one. 835 */ 836 if ((omp = vp->v_mount) != NULL) { 837 lwkt_gettoken(&omp->mnt_token); 838 KKASSERT(omp == vp->v_mount); 839 KASSERT(omp->mnt_nvnodelistsize > 0, 840 ("bad mount point vnode list size")); 841 vremovevnodemnt(vp); 842 omp->mnt_nvnodelistsize--; 843 lwkt_reltoken(&omp->mnt_token); 844 } 845 846 /* 847 * Insert into list of vnodes for the new mount point, if available. 848 * The 'end' of the LRU list is the vnode prior to mp->mnt_syncer. 849 */ 850 if (mp == NULL) { 851 vp->v_mount = NULL; 852 return; 853 } 854 lwkt_gettoken(&mp->mnt_token); 855 vp->v_mount = mp; 856 if (mp->mnt_syncer) { 857 TAILQ_INSERT_BEFORE(mp->mnt_syncer, vp, v_nmntvnodes); 858 } else { 859 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes); 860 } 861 mp->mnt_nvnodelistsize++; 862 lwkt_reltoken(&mp->mnt_token); 863 } 864 865 866 /* 867 * Scan the vnodes under a mount point and issue appropriate callbacks. 868 * 869 * The fastfunc() callback is called with just the mountlist token held 870 * (no vnode lock). It may not block and the vnode may be undergoing 871 * modifications while the caller is processing it. The vnode will 872 * not be entirely destroyed, however, due to the fact that the mountlist 873 * token is held. A return value < 0 skips to the next vnode without calling 874 * the slowfunc(), a return value > 0 terminates the loop. 875 * 876 * WARNING! The fastfunc() should not indirect through vp->v_object, the vp 877 * data structure is unstable when called from fastfunc(). 878 * 879 * The slowfunc() callback is called after the vnode has been successfully 880 * locked based on passed flags. The vnode is skipped if it gets rearranged 881 * or destroyed while blocking on the lock. A non-zero return value from 882 * the slow function terminates the loop. The slow function is allowed to 883 * arbitrarily block. The scanning code guarentees consistency of operation 884 * even if the slow function deletes or moves the node, or blocks and some 885 * other thread deletes or moves the node. 886 */ 887 int 888 vmntvnodescan( 889 struct mount *mp, 890 int flags, 891 int (*fastfunc)(struct mount *mp, struct vnode *vp, void *data), 892 int (*slowfunc)(struct mount *mp, struct vnode *vp, void *data), 893 void *data 894 ) { 895 struct vmntvnodescan_info info; 896 struct vnode *vp; 897 int r = 0; 898 int maxcount = mp->mnt_nvnodelistsize * 2; 899 int stopcount = 0; 900 int count = 0; 901 902 lwkt_gettoken(&mp->mnt_token); 903 904 /* 905 * If asked to do one pass stop after iterating available vnodes. 906 * Under heavy loads new vnodes can be added while we are scanning, 907 * so this isn't perfect. Create a slop factor of 2x. 908 */ 909 if (flags & VMSC_ONEPASS) 910 stopcount = mp->mnt_nvnodelistsize; 911 912 info.vp = TAILQ_FIRST(&mp->mnt_nvnodelist); 913 TAILQ_INSERT_TAIL(&mp->mnt_vnodescan_list, &info, entry); 914 915 while ((vp = info.vp) != NULL) { 916 if (--maxcount == 0) { 917 kprintf("Warning: excessive fssync iteration\n"); 918 maxcount = mp->mnt_nvnodelistsize * 2; 919 } 920 921 /* 922 * Skip if visible but not ready, or special (e.g. 923 * mp->mnt_syncer) 924 */ 925 if (vp->v_type == VNON) 926 goto next; 927 KKASSERT(vp->v_mount == mp); 928 929 /* 930 * Quick test. A negative return continues the loop without 931 * calling the slow test. 0 continues onto the slow test. 932 * A positive number aborts the loop. 933 */ 934 if (fastfunc) { 935 if ((r = fastfunc(mp, vp, data)) < 0) { 936 r = 0; 937 goto next; 938 } 939 if (r) 940 break; 941 } 942 943 /* 944 * Get a vxlock on the vnode, retry if it has moved or isn't 945 * in the mountlist where we expect it. 946 */ 947 if (slowfunc) { 948 int error; 949 950 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) { 951 case VMSC_GETVP: 952 error = vget(vp, LK_EXCLUSIVE); 953 break; 954 case VMSC_GETVP|VMSC_NOWAIT: 955 error = vget(vp, LK_EXCLUSIVE|LK_NOWAIT); 956 break; 957 case VMSC_GETVX: 958 vx_get(vp); 959 error = 0; 960 break; 961 default: 962 error = 0; 963 break; 964 } 965 if (error) 966 goto next; 967 /* 968 * Do not call the slow function if the vnode is 969 * invalid or if it was ripped out from under us 970 * while we (potentially) blocked. 971 */ 972 if (info.vp == vp && vp->v_type != VNON) 973 r = slowfunc(mp, vp, data); 974 975 /* 976 * Cleanup 977 */ 978 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) { 979 case VMSC_GETVP: 980 case VMSC_GETVP|VMSC_NOWAIT: 981 vput(vp); 982 break; 983 case VMSC_GETVX: 984 vx_put(vp); 985 break; 986 default: 987 break; 988 } 989 if (r != 0) 990 break; 991 } 992 993 next: 994 /* 995 * Yield after some processing. Depending on the number 996 * of vnodes, we might wind up running for a long time. 997 * Because threads are not preemptable, time critical 998 * userland processes might starve. Give them a chance 999 * now and then. 1000 */ 1001 if (++count == 10000) { 1002 /* 1003 * We really want to yield a bit, so we simply 1004 * sleep a tick 1005 */ 1006 tsleep(mp, 0, "vnodescn", 1); 1007 count = 0; 1008 } 1009 1010 /* 1011 * If doing one pass this decrements to zero. If it starts 1012 * at zero it is effectively unlimited for the purposes of 1013 * this loop. 1014 */ 1015 if (--stopcount == 0) 1016 break; 1017 1018 /* 1019 * Iterate. If the vnode was ripped out from under us 1020 * info.vp will already point to the next vnode, otherwise 1021 * we have to obtain the next valid vnode ourselves. 1022 */ 1023 if (info.vp == vp) 1024 info.vp = TAILQ_NEXT(vp, v_nmntvnodes); 1025 } 1026 1027 TAILQ_REMOVE(&mp->mnt_vnodescan_list, &info, entry); 1028 lwkt_reltoken(&mp->mnt_token); 1029 return(r); 1030 } 1031 1032 /* 1033 * Remove any vnodes in the vnode table belonging to mount point mp. 1034 * 1035 * If FORCECLOSE is not specified, there should not be any active ones, 1036 * return error if any are found (nb: this is a user error, not a 1037 * system error). If FORCECLOSE is specified, detach any active vnodes 1038 * that are found. 1039 * 1040 * If WRITECLOSE is set, only flush out regular file vnodes open for 1041 * writing. 1042 * 1043 * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped. 1044 * 1045 * `rootrefs' specifies the base reference count for the root vnode 1046 * of this filesystem. The root vnode is considered busy if its 1047 * v_refcnt exceeds this value. On a successful return, vflush() 1048 * will call vrele() on the root vnode exactly rootrefs times. 1049 * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must 1050 * be zero. 1051 */ 1052 static int debug_busyprt = 0; /* print out busy vnodes */ 1053 SYSCTL_INT(_vfs, OID_AUTO, debug_busyprt, CTLFLAG_RW, &debug_busyprt, 0, ""); 1054 1055 static int vflush_scan(struct mount *mp, struct vnode *vp, void *data); 1056 1057 struct vflush_info { 1058 int flags; 1059 int busy; 1060 thread_t td; 1061 }; 1062 1063 int 1064 vflush(struct mount *mp, int rootrefs, int flags) 1065 { 1066 struct thread *td = curthread; /* XXX */ 1067 struct vnode *rootvp = NULL; 1068 int error; 1069 struct vflush_info vflush_info; 1070 1071 if (rootrefs > 0) { 1072 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0, 1073 ("vflush: bad args")); 1074 /* 1075 * Get the filesystem root vnode. We can vput() it 1076 * immediately, since with rootrefs > 0, it won't go away. 1077 */ 1078 if ((error = VFS_ROOT(mp, &rootvp)) != 0) { 1079 if ((flags & FORCECLOSE) == 0) 1080 return (error); 1081 rootrefs = 0; 1082 /* continue anyway */ 1083 } 1084 if (rootrefs) 1085 vput(rootvp); 1086 } 1087 1088 vflush_info.busy = 0; 1089 vflush_info.flags = flags; 1090 vflush_info.td = td; 1091 vmntvnodescan(mp, VMSC_GETVX, NULL, vflush_scan, &vflush_info); 1092 1093 if (rootrefs > 0 && (flags & FORCECLOSE) == 0) { 1094 /* 1095 * If just the root vnode is busy, and if its refcount 1096 * is equal to `rootrefs', then go ahead and kill it. 1097 */ 1098 KASSERT(vflush_info.busy > 0, ("vflush: not busy")); 1099 KASSERT(VREFCNT(rootvp) >= rootrefs, ("vflush: rootrefs")); 1100 if (vflush_info.busy == 1 && VREFCNT(rootvp) == rootrefs) { 1101 vx_lock(rootvp); 1102 vgone_vxlocked(rootvp); 1103 vx_unlock(rootvp); 1104 vflush_info.busy = 0; 1105 } 1106 } 1107 if (vflush_info.busy) 1108 return (EBUSY); 1109 for (; rootrefs > 0; rootrefs--) 1110 vrele(rootvp); 1111 return (0); 1112 } 1113 1114 /* 1115 * The scan callback is made with an VX locked vnode. 1116 */ 1117 static int 1118 vflush_scan(struct mount *mp, struct vnode *vp, void *data) 1119 { 1120 struct vflush_info *info = data; 1121 struct vattr vattr; 1122 int flags = info->flags; 1123 1124 /* 1125 * Generally speaking try to deactivate on 0 refs (catch-all) 1126 */ 1127 atomic_set_int(&vp->v_refcnt, VREF_FINALIZE); 1128 1129 /* 1130 * Skip over a vnodes marked VSYSTEM. 1131 */ 1132 if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) { 1133 return(0); 1134 } 1135 1136 /* 1137 * Do not force-close VCHR or VBLK vnodes 1138 */ 1139 if (vp->v_type == VCHR || vp->v_type == VBLK) 1140 flags &= ~(WRITECLOSE|FORCECLOSE); 1141 1142 /* 1143 * If WRITECLOSE is set, flush out unlinked but still open 1144 * files (even if open only for reading) and regular file 1145 * vnodes open for writing. 1146 */ 1147 if ((flags & WRITECLOSE) && 1148 (vp->v_type == VNON || 1149 (VOP_GETATTR(vp, &vattr) == 0 && 1150 vattr.va_nlink > 0)) && 1151 (vp->v_writecount == 0 || vp->v_type != VREG)) { 1152 return(0); 1153 } 1154 1155 /* 1156 * If we are the only holder (refcnt of 1) or the vnode is in 1157 * termination (refcnt < 0), we can vgone the vnode. 1158 */ 1159 if (VREFCNT(vp) <= 1) { 1160 vgone_vxlocked(vp); 1161 return(0); 1162 } 1163 1164 /* 1165 * If FORCECLOSE is set, forcibly destroy the vnode and then move 1166 * it to a dummymount structure so vop_*() functions don't deref 1167 * a NULL pointer. 1168 */ 1169 if (flags & FORCECLOSE) { 1170 vhold(vp); 1171 vgone_vxlocked(vp); 1172 if (vp->v_mount == NULL) 1173 insmntque(vp, &dummymount); 1174 vdrop(vp); 1175 return(0); 1176 } 1177 if (vp->v_type == VCHR || vp->v_type == VBLK) 1178 kprintf("vflush: Warning, cannot destroy busy device vnode\n"); 1179 if (debug_busyprt) { 1180 const char *filename; 1181 1182 spin_lock(&vp->v_spin); 1183 filename = TAILQ_FIRST(&vp->v_namecache) ? 1184 TAILQ_FIRST(&vp->v_namecache)->nc_name : "?"; 1185 spin_unlock(&vp->v_spin); 1186 kprintf("vflush: busy vnode (%p) %s\n", vp, filename); 1187 } 1188 ++info->busy; 1189 return(0); 1190 } 1191 1192 void 1193 add_bio_ops(struct bio_ops *ops) 1194 { 1195 TAILQ_INSERT_TAIL(&bio_ops_list, ops, entry); 1196 } 1197 1198 void 1199 rem_bio_ops(struct bio_ops *ops) 1200 { 1201 TAILQ_REMOVE(&bio_ops_list, ops, entry); 1202 } 1203 1204 /* 1205 * This calls the bio_ops io_sync function either for a mount point 1206 * or generally. 1207 * 1208 * WARNING: softdeps is weirdly coded and just isn't happy unless 1209 * io_sync is called with a NULL mount from the general syncing code. 1210 */ 1211 void 1212 bio_ops_sync(struct mount *mp) 1213 { 1214 struct bio_ops *ops; 1215 1216 if (mp) { 1217 if ((ops = mp->mnt_bioops) != NULL) 1218 ops->io_sync(mp); 1219 } else { 1220 TAILQ_FOREACH(ops, &bio_ops_list, entry) { 1221 ops->io_sync(NULL); 1222 } 1223 } 1224 } 1225 1226 /* 1227 * Lookup a mount point by nch 1228 */ 1229 struct mount * 1230 mount_get_by_nc(struct namecache *ncp) 1231 { 1232 struct mount *mp = NULL; 1233 1234 lwkt_gettoken_shared(&mountlist_token); 1235 TAILQ_FOREACH(mp, &mountlist, mnt_list) { 1236 if (ncp == mp->mnt_ncmountpt.ncp) 1237 break; 1238 } 1239 lwkt_reltoken(&mountlist_token); 1240 1241 return (mp); 1242 } 1243 1244