1 /* 2 * Copyright (c) 2004,2013-2022 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 * Do not allow this thread to become cpu-bound if something 572 * goes wrong. 573 */ 574 tsleep(vnlruthread, 0, "vlruwt", 1); 575 } 576 } 577 578 /* 579 * MOUNTLIST FUNCTIONS 580 */ 581 582 /* 583 * mountlist_insert (MP SAFE) 584 * 585 * Add a new mount point to the mount list. Filesystem should attempt to 586 * supply a unique fsid but if a duplicate occurs adjust the fsid to ensure 587 * uniqueness. 588 */ 589 void 590 mountlist_insert(struct mount *mp, int how) 591 { 592 int lim = 0x01000000; 593 594 lwkt_gettoken(&mountlist_token); 595 if (how == MNTINS_FIRST) 596 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list); 597 else 598 TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); 599 while (mount_rb_tree_RB_INSERT(&mounttree, mp)) { 600 int32_t val; 601 602 /* 603 * minor device mask: 0xFFFF00FF 604 */ 605 val = mp->mnt_stat.f_fsid.val[0]; 606 val = ((val & 0xFFFF0000) >> 8) | (val & 0x000000FF); 607 ++val; 608 val = ((val << 8) & 0xFFFF0000) | (val & 0x000000FF); 609 mp->mnt_stat.f_fsid.val[0] = val; 610 if (--lim == 0) { 611 lim = 0x01000000; 612 mp->mnt_stat.f_fsid.val[1] += 0x0100; 613 kprintf("mountlist_insert: fsid collision, " 614 "too many mounts\n"); 615 } 616 } 617 lwkt_reltoken(&mountlist_token); 618 } 619 620 /* 621 * mountlist_interlock (MP SAFE) 622 * 623 * Execute the specified interlock function with the mountlist token 624 * held. The function will be called in a serialized fashion verses 625 * other functions called through this mechanism. 626 * 627 * The function is expected to be very short-lived. 628 */ 629 int 630 mountlist_interlock(int (*callback)(struct mount *), struct mount *mp) 631 { 632 int error; 633 634 lwkt_gettoken(&mountlist_token); 635 error = callback(mp); 636 lwkt_reltoken(&mountlist_token); 637 return (error); 638 } 639 640 /* 641 * mountlist_boot_getfirst (DURING BOOT ONLY) 642 * 643 * This function returns the first mount on the mountlist, which is 644 * expected to be the root mount. Since no interlocks are obtained 645 * this function is only safe to use during booting. 646 */ 647 648 struct mount * 649 mountlist_boot_getfirst(void) 650 { 651 return(TAILQ_FIRST(&mountlist)); 652 } 653 654 /* 655 * mountlist_remove (MP SAFE) 656 * 657 * Remove a node from the mountlist. If this node is the next scan node 658 * for any active mountlist scans, the active mountlist scan will be 659 * adjusted to skip the node, thus allowing removals during mountlist 660 * scans. 661 */ 662 void 663 mountlist_remove(struct mount *mp) 664 { 665 struct mountscan_info *msi; 666 667 lwkt_gettoken(&mountlist_token); 668 TAILQ_FOREACH(msi, &mountscan_list, msi_entry) { 669 if (msi->msi_node == mp) { 670 if (msi->msi_how & MNTSCAN_FORWARD) 671 msi->msi_node = TAILQ_NEXT(mp, mnt_list); 672 else 673 msi->msi_node = TAILQ_PREV(mp, mntlist, 674 mnt_list); 675 } 676 } 677 TAILQ_REMOVE(&mountlist, mp, mnt_list); 678 mount_rb_tree_RB_REMOVE(&mounttree, mp); 679 lwkt_reltoken(&mountlist_token); 680 } 681 682 /* 683 * mountlist_exists (MP SAFE) 684 * 685 * Checks if a node exists in the mountlist. 686 * This function is mainly used by VFS quota code to check if a 687 * cached nullfs struct mount pointer is still valid at use time 688 * 689 * FIXME: there is no warranty the mp passed to that function 690 * will be the same one used by VFS_ACCOUNT() later 691 */ 692 int 693 mountlist_exists(struct mount *mp) 694 { 695 int node_exists = 0; 696 struct mount* lmp; 697 698 lwkt_gettoken_shared(&mountlist_token); 699 TAILQ_FOREACH(lmp, &mountlist, mnt_list) { 700 if (lmp == mp) { 701 node_exists = 1; 702 break; 703 } 704 } 705 lwkt_reltoken(&mountlist_token); 706 707 return(node_exists); 708 } 709 710 /* 711 * mountlist_scan 712 * 713 * Safely scan the mount points on the mount list. Each mountpoint 714 * is held across the callback. The callback is responsible for 715 * acquiring any further tokens or locks. 716 * 717 * Unless otherwise specified each mount point will be busied prior to the 718 * callback and unbusied afterwords. The callback may safely remove any 719 * mount point without interfering with the scan. If the current callback 720 * mount is removed the scanner will not attempt to unbusy it. 721 * 722 * If a mount node cannot be busied it is silently skipped. 723 * 724 * The callback return value is aggregated and a total is returned. A return 725 * value of < 0 is not aggregated and will terminate the scan. 726 * 727 * MNTSCAN_FORWARD - the mountlist is scanned in the forward direction 728 * MNTSCAN_REVERSE - the mountlist is scanned in reverse 729 * MNTSCAN_NOBUSY - the scanner will make the callback without busying 730 * the mount node. 731 * MNTSCAN_NOUNLOCK - Do not unlock mountlist_token across callback 732 * 733 * NOTE: mountlist_token is not held across the callback. 734 */ 735 int 736 mountlist_scan(int (*callback)(struct mount *, void *), void *data, int how) 737 { 738 struct mountscan_info info; 739 struct mount *mp; 740 int count; 741 int res; 742 int dounlock = ((how & MNTSCAN_NOUNLOCK) == 0); 743 744 lwkt_gettoken(&mountlist_token); 745 info.msi_how = how; 746 info.msi_node = NULL; /* paranoia */ 747 TAILQ_INSERT_TAIL(&mountscan_list, &info, msi_entry); 748 lwkt_reltoken(&mountlist_token); 749 750 res = 0; 751 lwkt_gettoken_shared(&mountlist_token); 752 753 if (how & MNTSCAN_FORWARD) { 754 info.msi_node = TAILQ_FIRST(&mountlist); 755 while ((mp = info.msi_node) != NULL) { 756 mount_hold(mp); 757 if (how & MNTSCAN_NOBUSY) { 758 if (dounlock) 759 lwkt_reltoken(&mountlist_token); 760 count = callback(mp, data); 761 if (dounlock) 762 lwkt_gettoken_shared(&mountlist_token); 763 } else if (vfs_busy(mp, LK_NOWAIT) == 0) { 764 if (dounlock) 765 lwkt_reltoken(&mountlist_token); 766 count = callback(mp, data); 767 if (dounlock) 768 lwkt_gettoken_shared(&mountlist_token); 769 if (mp == info.msi_node) 770 vfs_unbusy(mp); 771 } else { 772 count = 0; 773 } 774 mount_drop(mp); 775 if (count < 0) 776 break; 777 res += count; 778 if (mp == info.msi_node) 779 info.msi_node = TAILQ_NEXT(mp, mnt_list); 780 } 781 } else if (how & MNTSCAN_REVERSE) { 782 info.msi_node = TAILQ_LAST(&mountlist, mntlist); 783 while ((mp = info.msi_node) != NULL) { 784 mount_hold(mp); 785 if (how & MNTSCAN_NOBUSY) { 786 if (dounlock) 787 lwkt_reltoken(&mountlist_token); 788 count = callback(mp, data); 789 if (dounlock) 790 lwkt_gettoken_shared(&mountlist_token); 791 } else if (vfs_busy(mp, LK_NOWAIT) == 0) { 792 if (dounlock) 793 lwkt_reltoken(&mountlist_token); 794 count = callback(mp, data); 795 if (dounlock) 796 lwkt_gettoken_shared(&mountlist_token); 797 if (mp == info.msi_node) 798 vfs_unbusy(mp); 799 } else { 800 count = 0; 801 } 802 mount_drop(mp); 803 if (count < 0) 804 break; 805 res += count; 806 if (mp == info.msi_node) 807 info.msi_node = TAILQ_PREV(mp, mntlist, 808 mnt_list); 809 } 810 } 811 lwkt_reltoken(&mountlist_token); 812 813 lwkt_gettoken(&mountlist_token); 814 TAILQ_REMOVE(&mountscan_list, &info, msi_entry); 815 lwkt_reltoken(&mountlist_token); 816 817 return(res); 818 } 819 820 /* 821 * MOUNT RELATED VNODE FUNCTIONS 822 */ 823 824 static struct kproc_desc vnlru_kp = { 825 "vnlru", 826 vnlru_proc, 827 &vnlruthread 828 }; 829 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp); 830 831 /* 832 * Move a vnode from one mount queue to another. 833 */ 834 void 835 insmntque(struct vnode *vp, struct mount *mp) 836 { 837 struct mount *omp; 838 839 /* 840 * Delete from old mount point vnode list, if on one. 841 */ 842 if ((omp = vp->v_mount) != NULL) { 843 lwkt_gettoken(&omp->mnt_token); 844 KKASSERT(omp == vp->v_mount); 845 KASSERT(omp->mnt_nvnodelistsize > 0, 846 ("bad mount point vnode list size")); 847 vremovevnodemnt(vp); 848 omp->mnt_nvnodelistsize--; 849 lwkt_reltoken(&omp->mnt_token); 850 } 851 852 /* 853 * Insert into list of vnodes for the new mount point, if available. 854 * The 'end' of the LRU list is the vnode prior to mp->mnt_syncer. 855 */ 856 if (mp == NULL) { 857 vp->v_mount = NULL; 858 return; 859 } 860 lwkt_gettoken(&mp->mnt_token); 861 vp->v_mount = mp; 862 if (mp->mnt_syncer) { 863 TAILQ_INSERT_BEFORE(mp->mnt_syncer, vp, v_nmntvnodes); 864 } else { 865 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes); 866 } 867 mp->mnt_nvnodelistsize++; 868 lwkt_reltoken(&mp->mnt_token); 869 } 870 871 872 /* 873 * Scan the vnodes under a mount point and issue appropriate callbacks. 874 * 875 * The fastfunc() callback is called with just the mountlist token held 876 * (no vnode lock). It may not block and the vnode may be undergoing 877 * modifications while the caller is processing it. The vnode will 878 * not be entirely destroyed, however, due to the fact that the mountlist 879 * token is held. A return value < 0 skips to the next vnode without calling 880 * the slowfunc(), a return value > 0 terminates the loop. 881 * 882 * WARNING! The fastfunc() should not indirect through vp->v_object, the vp 883 * data structure is unstable when called from fastfunc(). 884 * 885 * The slowfunc() callback is called after the vnode has been successfully 886 * locked based on passed flags. The vnode is skipped if it gets rearranged 887 * or destroyed while blocking on the lock. A non-zero return value from 888 * the slow function terminates the loop. The slow function is allowed to 889 * arbitrarily block. The scanning code guarentees consistency of operation 890 * even if the slow function deletes or moves the node, or blocks and some 891 * other thread deletes or moves the node. 892 */ 893 int 894 vmntvnodescan( 895 struct mount *mp, 896 int flags, 897 int (*fastfunc)(struct mount *mp, struct vnode *vp, void *data), 898 int (*slowfunc)(struct mount *mp, struct vnode *vp, void *data), 899 void *data 900 ) { 901 struct vmntvnodescan_info info; 902 struct vnode *vp; 903 int r = 0; 904 int maxcount = mp->mnt_nvnodelistsize * 2; 905 int stopcount = 0; 906 int count = 0; 907 908 lwkt_gettoken(&mp->mnt_token); 909 910 /* 911 * If asked to do one pass stop after iterating available vnodes. 912 * Under heavy loads new vnodes can be added while we are scanning, 913 * so this isn't perfect. Create a slop factor of 2x. 914 */ 915 if (flags & VMSC_ONEPASS) 916 stopcount = mp->mnt_nvnodelistsize; 917 918 info.vp = TAILQ_FIRST(&mp->mnt_nvnodelist); 919 TAILQ_INSERT_TAIL(&mp->mnt_vnodescan_list, &info, entry); 920 921 while ((vp = info.vp) != NULL) { 922 if (--maxcount == 0) { 923 kprintf("Warning: excessive fssync iteration\n"); 924 maxcount = mp->mnt_nvnodelistsize * 2; 925 } 926 927 /* 928 * Skip if visible but not ready, or special (e.g. 929 * mp->mnt_syncer) 930 */ 931 if (vp->v_type == VNON) 932 goto next; 933 KKASSERT(vp->v_mount == mp); 934 935 /* 936 * Quick test. A negative return continues the loop without 937 * calling the slow test. 0 continues onto the slow test. 938 * A positive number aborts the loop. 939 */ 940 if (fastfunc) { 941 if ((r = fastfunc(mp, vp, data)) < 0) { 942 r = 0; 943 goto next; 944 } 945 if (r) 946 break; 947 } 948 949 /* 950 * Get a vxlock on the vnode, retry if it has moved or isn't 951 * in the mountlist where we expect it. 952 */ 953 if (slowfunc) { 954 int error; 955 956 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) { 957 case VMSC_GETVP: 958 error = vget(vp, LK_EXCLUSIVE); 959 break; 960 case VMSC_GETVP|VMSC_NOWAIT: 961 error = vget(vp, LK_EXCLUSIVE|LK_NOWAIT); 962 break; 963 case VMSC_GETVX: 964 vx_get(vp); 965 error = 0; 966 break; 967 default: 968 error = 0; 969 break; 970 } 971 if (error) 972 goto next; 973 /* 974 * Do not call the slow function if the vnode is 975 * invalid or if it was ripped out from under us 976 * while we (potentially) blocked. 977 */ 978 if (info.vp == vp && vp->v_type != VNON) 979 r = slowfunc(mp, vp, data); 980 981 /* 982 * Cleanup 983 */ 984 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) { 985 case VMSC_GETVP: 986 case VMSC_GETVP|VMSC_NOWAIT: 987 vput(vp); 988 break; 989 case VMSC_GETVX: 990 vx_put(vp); 991 break; 992 default: 993 break; 994 } 995 if (r != 0) 996 break; 997 } 998 999 next: 1000 /* 1001 * Yield after some processing. Depending on the number 1002 * of vnodes, we might wind up running for a long time. 1003 * Because threads are not preemptable, time critical 1004 * userland processes might starve. Give them a chance 1005 * now and then. 1006 */ 1007 if (++count == 10000) { 1008 /* 1009 * We really want to yield a bit, so we simply 1010 * sleep a tick 1011 */ 1012 tsleep(mp, 0, "vnodescn", 1); 1013 count = 0; 1014 } 1015 1016 /* 1017 * If doing one pass this decrements to zero. If it starts 1018 * at zero it is effectively unlimited for the purposes of 1019 * this loop. 1020 */ 1021 if (--stopcount == 0) 1022 break; 1023 1024 /* 1025 * Iterate. If the vnode was ripped out from under us 1026 * info.vp will already point to the next vnode, otherwise 1027 * we have to obtain the next valid vnode ourselves. 1028 */ 1029 if (info.vp == vp) 1030 info.vp = TAILQ_NEXT(vp, v_nmntvnodes); 1031 } 1032 1033 TAILQ_REMOVE(&mp->mnt_vnodescan_list, &info, entry); 1034 lwkt_reltoken(&mp->mnt_token); 1035 return(r); 1036 } 1037 1038 /* 1039 * Remove any vnodes in the vnode table belonging to mount point mp. 1040 * 1041 * If FORCECLOSE is not specified, there should not be any active ones, 1042 * return error if any are found (nb: this is a user error, not a 1043 * system error). If FORCECLOSE is specified, detach any active vnodes 1044 * that are found. 1045 * 1046 * If WRITECLOSE is set, only flush out regular file vnodes open for 1047 * writing. 1048 * 1049 * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped. 1050 * 1051 * `rootrefs' specifies the base reference count for the root vnode 1052 * of this filesystem. The root vnode is considered busy if its 1053 * v_refcnt exceeds this value. On a successful return, vflush() 1054 * will call vrele() on the root vnode exactly rootrefs times. 1055 * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must 1056 * be zero. 1057 */ 1058 static int debug_busyprt = 0; /* print out busy vnodes */ 1059 SYSCTL_INT(_vfs, OID_AUTO, debug_busyprt, CTLFLAG_RW, &debug_busyprt, 0, ""); 1060 1061 static int vflush_scan(struct mount *mp, struct vnode *vp, void *data); 1062 1063 struct vflush_info { 1064 int flags; 1065 int busy; 1066 thread_t td; 1067 }; 1068 1069 int 1070 vflush(struct mount *mp, int rootrefs, int flags) 1071 { 1072 struct thread *td = curthread; /* XXX */ 1073 struct vnode *rootvp = NULL; 1074 int error; 1075 struct vflush_info vflush_info; 1076 1077 if (rootrefs > 0) { 1078 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0, 1079 ("vflush: bad args")); 1080 /* 1081 * Get the filesystem root vnode. We can vput() it 1082 * immediately, since with rootrefs > 0, it won't go away. 1083 */ 1084 if ((error = VFS_ROOT(mp, &rootvp)) != 0) { 1085 if ((flags & FORCECLOSE) == 0) 1086 return (error); 1087 rootrefs = 0; 1088 /* continue anyway */ 1089 } 1090 if (rootrefs) 1091 vput(rootvp); 1092 } 1093 1094 vflush_info.busy = 0; 1095 vflush_info.flags = flags; 1096 vflush_info.td = td; 1097 vmntvnodescan(mp, VMSC_GETVX, NULL, vflush_scan, &vflush_info); 1098 1099 if (rootrefs > 0 && (flags & FORCECLOSE) == 0) { 1100 /* 1101 * If just the root vnode is busy, and if its refcount 1102 * is equal to `rootrefs', then go ahead and kill it. 1103 */ 1104 KASSERT(vflush_info.busy > 0, ("vflush: not busy")); 1105 KASSERT(VREFCNT(rootvp) >= rootrefs, ("vflush: rootrefs")); 1106 if (vflush_info.busy == 1 && VREFCNT(rootvp) == rootrefs) { 1107 vx_lock(rootvp); 1108 vgone_vxlocked(rootvp); 1109 vx_unlock(rootvp); 1110 vflush_info.busy = 0; 1111 } 1112 } 1113 if (vflush_info.busy) 1114 return (EBUSY); 1115 for (; rootrefs > 0; rootrefs--) 1116 vrele(rootvp); 1117 return (0); 1118 } 1119 1120 /* 1121 * The scan callback is made with an VX locked vnode. 1122 */ 1123 static int 1124 vflush_scan(struct mount *mp, struct vnode *vp, void *data) 1125 { 1126 struct vflush_info *info = data; 1127 struct vattr vattr; 1128 int flags = info->flags; 1129 1130 /* 1131 * Generally speaking try to deactivate on 0 refs (catch-all) 1132 */ 1133 atomic_set_int(&vp->v_refcnt, VREF_FINALIZE); 1134 1135 /* 1136 * Skip over a vnodes marked VSYSTEM. 1137 */ 1138 if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) { 1139 return(0); 1140 } 1141 1142 /* 1143 * Do not force-close VCHR or VBLK vnodes 1144 */ 1145 if (vp->v_type == VCHR || vp->v_type == VBLK) 1146 flags &= ~(WRITECLOSE|FORCECLOSE); 1147 1148 /* 1149 * If WRITECLOSE is set, flush out unlinked but still open 1150 * files (even if open only for reading) and regular file 1151 * vnodes open for writing. 1152 */ 1153 if ((flags & WRITECLOSE) && 1154 (vp->v_type == VNON || 1155 (VOP_GETATTR(vp, &vattr) == 0 && 1156 vattr.va_nlink > 0)) && 1157 (vp->v_writecount == 0 || vp->v_type != VREG)) { 1158 return(0); 1159 } 1160 1161 /* 1162 * If we are the only holder (refcnt of 1) or the vnode is in 1163 * termination (refcnt < 0), we can vgone the vnode. 1164 */ 1165 if (VREFCNT(vp) <= 1) { 1166 vgone_vxlocked(vp); 1167 return(0); 1168 } 1169 1170 /* 1171 * If FORCECLOSE is set, forcibly destroy the vnode and then move 1172 * it to a dummymount structure so vop_*() functions don't deref 1173 * a NULL pointer. 1174 */ 1175 if (flags & FORCECLOSE) { 1176 vhold(vp); 1177 vgone_vxlocked(vp); 1178 if (vp->v_mount == NULL) 1179 insmntque(vp, &dummymount); 1180 vdrop(vp); 1181 return(0); 1182 } 1183 if (vp->v_type == VCHR || vp->v_type == VBLK) 1184 kprintf("vflush: Warning, cannot destroy busy device vnode\n"); 1185 if (debug_busyprt) { 1186 const char *filename; 1187 1188 spin_lock(&vp->v_spin); 1189 filename = TAILQ_FIRST(&vp->v_namecache) ? 1190 TAILQ_FIRST(&vp->v_namecache)->nc_name : "?"; 1191 spin_unlock(&vp->v_spin); 1192 kprintf("vflush: busy vnode (%p) %s\n", vp, filename); 1193 } 1194 ++info->busy; 1195 return(0); 1196 } 1197 1198 void 1199 add_bio_ops(struct bio_ops *ops) 1200 { 1201 TAILQ_INSERT_TAIL(&bio_ops_list, ops, entry); 1202 } 1203 1204 void 1205 rem_bio_ops(struct bio_ops *ops) 1206 { 1207 TAILQ_REMOVE(&bio_ops_list, ops, entry); 1208 } 1209 1210 /* 1211 * This calls the bio_ops io_sync function either for a mount point 1212 * or generally. 1213 * 1214 * WARNING: softdeps is weirdly coded and just isn't happy unless 1215 * io_sync is called with a NULL mount from the general syncing code. 1216 */ 1217 void 1218 bio_ops_sync(struct mount *mp) 1219 { 1220 struct bio_ops *ops; 1221 1222 if (mp) { 1223 if ((ops = mp->mnt_bioops) != NULL) 1224 ops->io_sync(mp); 1225 } else { 1226 TAILQ_FOREACH(ops, &bio_ops_list, entry) { 1227 ops->io_sync(NULL); 1228 } 1229 } 1230 } 1231 1232 /* 1233 * Lookup a mount point by nch 1234 */ 1235 struct mount * 1236 mount_get_by_nc(struct namecache *ncp) 1237 { 1238 struct mount *mp = NULL; 1239 1240 lwkt_gettoken_shared(&mountlist_token); 1241 TAILQ_FOREACH(mp, &mountlist, mnt_list) { 1242 if (ncp == mp->mnt_ncmountpt.ncp) 1243 break; 1244 } 1245 lwkt_reltoken(&mountlist_token); 1246 1247 return (mp); 1248 } 1249 1250