| 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 1.24 2006/12/23 00:35:04 swildner 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 | struct mountscan_info { |
| 99 | TAILQ_ENTRY(mountscan_info) msi_entry; |
| 100 | int msi_how; |
| 101 | struct mount *msi_node; |
| 102 | }; |
| 103 | |
| 104 | struct vmntvnodescan_info { |
| 105 | TAILQ_ENTRY(vmntvnodescan_info) entry; |
| 106 | struct vnode *vp; |
| 107 | }; |
| 108 | |
| 109 | static int vnlru_nowhere = 0; |
| 110 | SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RD, |
| 111 | &vnlru_nowhere, 0, |
| 112 | "Number of times the vnlru process ran without success"); |
| 113 | |
| 114 | |
| 115 | static struct lwkt_token mntid_token; |
| 116 | |
| 117 | static struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist); |
| 118 | static TAILQ_HEAD(,mountscan_info) mountscan_list; |
| 119 | static struct lwkt_token mountlist_token; |
| 120 | static TAILQ_HEAD(,vmntvnodescan_info) mntvnodescan_list; |
| 121 | struct lwkt_token mntvnode_token; |
| 122 | |
| 123 | /* |
| 124 | * Called from vfsinit() |
| 125 | */ |
| 126 | void |
| 127 | vfs_mount_init(void) |
| 128 | { |
| 129 | lwkt_token_init(&mountlist_token); |
| 130 | lwkt_token_init(&mntvnode_token); |
| 131 | lwkt_token_init(&mntid_token); |
| 132 | TAILQ_INIT(&mountscan_list); |
| 133 | TAILQ_INIT(&mntvnodescan_list); |
| 134 | } |
| 135 | |
| 136 | /* |
| 137 | * Support function called with mntvnode_token held to remove a vnode |
| 138 | * from the mountlist. We must update any list scans which are in progress. |
| 139 | */ |
| 140 | static void |
| 141 | vremovevnodemnt(struct vnode *vp) |
| 142 | { |
| 143 | struct vmntvnodescan_info *info; |
| 144 | |
| 145 | TAILQ_FOREACH(info, &mntvnodescan_list, entry) { |
| 146 | if (info->vp == vp) |
| 147 | info->vp = TAILQ_NEXT(vp, v_nmntvnodes); |
| 148 | } |
| 149 | TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes); |
| 150 | } |
| 151 | |
| 152 | /* |
| 153 | * Support function called with mntvnode_token held to move a vnode to |
| 154 | * the end of the list. |
| 155 | */ |
| 156 | static void |
| 157 | vmovevnodetoend(struct mount *mp, struct vnode *vp) |
| 158 | { |
| 159 | vremovevnodemnt(vp); |
| 160 | TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes); |
| 161 | } |
| 162 | |
| 163 | |
| 164 | /* |
| 165 | * Allocate a new vnode and associate it with a tag, mount point, and |
| 166 | * operations vector. |
| 167 | * |
| 168 | * A VX locked and refd vnode is returned. The caller should setup the |
| 169 | * remaining fields and vx_put() or, if he wishes to leave a vref, |
| 170 | * vx_unlock() the vnode. |
| 171 | */ |
| 172 | int |
| 173 | getnewvnode(enum vtagtype tag, struct mount *mp, |
| 174 | struct vnode **vpp, int lktimeout, int lkflags) |
| 175 | { |
| 176 | struct vnode *vp; |
| 177 | |
| 178 | KKASSERT(mp != NULL); |
| 179 | |
| 180 | vp = allocvnode(lktimeout, lkflags); |
| 181 | vp->v_tag = tag; |
| 182 | vp->v_data = NULL; |
| 183 | |
| 184 | /* |
| 185 | * By default the vnode is assigned the mount point's normal |
| 186 | * operations vector. |
| 187 | */ |
| 188 | vp->v_ops = &mp->mnt_vn_use_ops; |
| 189 | |
| 190 | /* |
| 191 | * Placing the vnode on the mount point's queue makes it visible. |
| 192 | * VNON prevents it from being messed with, however. |
| 193 | */ |
| 194 | insmntque(vp, mp); |
| 195 | |
| 196 | /* |
| 197 | * A VX locked & refd vnode is returned. |
| 198 | */ |
| 199 | *vpp = vp; |
| 200 | return (0); |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * This function creates vnodes with special operations vectors. The |
| 205 | * mount point is optional. |
| 206 | * |
| 207 | * This routine is being phased out. |
| 208 | */ |
| 209 | int |
| 210 | getspecialvnode(enum vtagtype tag, struct mount *mp, |
| 211 | struct vop_ops **ops, |
| 212 | struct vnode **vpp, int lktimeout, int lkflags) |
| 213 | { |
| 214 | struct vnode *vp; |
| 215 | |
| 216 | vp = allocvnode(lktimeout, lkflags); |
| 217 | vp->v_tag = tag; |
| 218 | vp->v_data = NULL; |
| 219 | vp->v_ops = ops; |
| 220 | |
| 221 | /* |
| 222 | * Placing the vnode on the mount point's queue makes it visible. |
| 223 | * VNON prevents it from being messed with, however. |
| 224 | */ |
| 225 | insmntque(vp, mp); |
| 226 | |
| 227 | /* |
| 228 | * A VX locked & refd vnode is returned. |
| 229 | */ |
| 230 | *vpp = vp; |
| 231 | return (0); |
| 232 | } |
| 233 | |
| 234 | /* |
| 235 | * Interlock against an unmount, return 0 on success, non-zero on failure. |
| 236 | * |
| 237 | * The passed flag may be 0 or LK_NOWAIT and is only used if an unmount |
| 238 | * is in-progress. |
| 239 | * |
| 240 | * If no unmount is in-progress LK_NOWAIT is ignored. No other flag bits |
| 241 | * are used. A shared locked will be obtained and the filesystem will not |
| 242 | * be unmountable until the lock is released. |
| 243 | */ |
| 244 | int |
| 245 | vfs_busy(struct mount *mp, int flags) |
| 246 | { |
| 247 | int lkflags; |
| 248 | |
| 249 | if (mp->mnt_kern_flag & MNTK_UNMOUNT) { |
| 250 | if (flags & LK_NOWAIT) |
| 251 | return (ENOENT); |
| 252 | /* XXX not MP safe */ |
| 253 | mp->mnt_kern_flag |= MNTK_MWAIT; |
| 254 | /* |
| 255 | * Since all busy locks are shared except the exclusive |
| 256 | * lock granted when unmounting, the only place that a |
| 257 | * wakeup needs to be done is at the release of the |
| 258 | * exclusive lock at the end of dounmount. |
| 259 | */ |
| 260 | tsleep((caddr_t)mp, 0, "vfs_busy", 0); |
| 261 | return (ENOENT); |
| 262 | } |
| 263 | lkflags = LK_SHARED; |
| 264 | if (lockmgr(&mp->mnt_lock, lkflags)) |
| 265 | panic("vfs_busy: unexpected lock failure"); |
| 266 | return (0); |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | * Free a busy filesystem. |
| 271 | */ |
| 272 | void |
| 273 | vfs_unbusy(struct mount *mp) |
| 274 | { |
| 275 | lockmgr(&mp->mnt_lock, LK_RELEASE); |
| 276 | } |
| 277 | |
| 278 | /* |
| 279 | * Lookup a filesystem type, and if found allocate and initialize |
| 280 | * a mount structure for it. |
| 281 | * |
| 282 | * Devname is usually updated by mount(8) after booting. |
| 283 | */ |
| 284 | int |
| 285 | vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp) |
| 286 | { |
| 287 | struct vfsconf *vfsp; |
| 288 | struct mount *mp; |
| 289 | |
| 290 | if (fstypename == NULL) |
| 291 | return (ENODEV); |
| 292 | for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) { |
| 293 | if (!strcmp(vfsp->vfc_name, fstypename)) |
| 294 | break; |
| 295 | } |
| 296 | if (vfsp == NULL) |
| 297 | return (ENODEV); |
| 298 | mp = kmalloc(sizeof(struct mount), M_MOUNT, M_WAITOK); |
| 299 | bzero((char *)mp, (u_long)sizeof(struct mount)); |
| 300 | lockinit(&mp->mnt_lock, "vfslock", VLKTIMEOUT, 0); |
| 301 | vfs_busy(mp, LK_NOWAIT); |
| 302 | TAILQ_INIT(&mp->mnt_nvnodelist); |
| 303 | TAILQ_INIT(&mp->mnt_reservedvnlist); |
| 304 | TAILQ_INIT(&mp->mnt_jlist); |
| 305 | mp->mnt_nvnodelistsize = 0; |
| 306 | mp->mnt_vfc = vfsp; |
| 307 | mp->mnt_op = vfsp->vfc_vfsops; |
| 308 | mp->mnt_flag = MNT_RDONLY; |
| 309 | vfsp->vfc_refcount++; |
| 310 | mp->mnt_iosize_max = DFLTPHYS; |
| 311 | mp->mnt_stat.f_type = vfsp->vfc_typenum; |
| 312 | mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK; |
| 313 | strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN); |
| 314 | copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0); |
| 315 | *mpp = mp; |
| 316 | return (0); |
| 317 | } |
| 318 | |
| 319 | /* |
| 320 | * Lookup a mount point by filesystem identifier. |
| 321 | */ |
| 322 | struct mount * |
| 323 | vfs_getvfs(fsid_t *fsid) |
| 324 | { |
| 325 | struct mount *mp; |
| 326 | lwkt_tokref ilock; |
| 327 | |
| 328 | lwkt_gettoken(&ilock, &mountlist_token); |
| 329 | TAILQ_FOREACH(mp, &mountlist, mnt_list) { |
| 330 | if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] && |
| 331 | mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) { |
| 332 | break; |
| 333 | } |
| 334 | } |
| 335 | lwkt_reltoken(&ilock); |
| 336 | return (mp); |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | * Get a new unique fsid. Try to make its val[0] unique, since this value |
| 341 | * will be used to create fake device numbers for stat(). Also try (but |
| 342 | * not so hard) make its val[0] unique mod 2^16, since some emulators only |
| 343 | * support 16-bit device numbers. We end up with unique val[0]'s for the |
| 344 | * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls. |
| 345 | * |
| 346 | * Keep in mind that several mounts may be running in parallel. Starting |
| 347 | * the search one past where the previous search terminated is both a |
| 348 | * micro-optimization and a defense against returning the same fsid to |
| 349 | * different mounts. |
| 350 | */ |
| 351 | void |
| 352 | vfs_getnewfsid(struct mount *mp) |
| 353 | { |
| 354 | static u_int16_t mntid_base; |
| 355 | lwkt_tokref ilock; |
| 356 | fsid_t tfsid; |
| 357 | int mtype; |
| 358 | |
| 359 | lwkt_gettoken(&ilock, &mntid_token); |
| 360 | mtype = mp->mnt_vfc->vfc_typenum; |
| 361 | tfsid.val[1] = mtype; |
| 362 | mtype = (mtype & 0xFF) << 24; |
| 363 | for (;;) { |
| 364 | tfsid.val[0] = makeudev(255, |
| 365 | mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF)); |
| 366 | mntid_base++; |
| 367 | if (vfs_getvfs(&tfsid) == NULL) |
| 368 | break; |
| 369 | } |
| 370 | mp->mnt_stat.f_fsid.val[0] = tfsid.val[0]; |
| 371 | mp->mnt_stat.f_fsid.val[1] = tfsid.val[1]; |
| 372 | lwkt_reltoken(&ilock); |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * This routine is called when we have too many vnodes. It attempts |
| 377 | * to free <count> vnodes and will potentially free vnodes that still |
| 378 | * have VM backing store (VM backing store is typically the cause |
| 379 | * of a vnode blowout so we want to do this). Therefore, this operation |
| 380 | * is not considered cheap. |
| 381 | * |
| 382 | * A number of conditions may prevent a vnode from being reclaimed. |
| 383 | * the buffer cache may have references on the vnode, a directory |
| 384 | * vnode may still have references due to the namei cache representing |
| 385 | * underlying files, or the vnode may be in active use. It is not |
| 386 | * desireable to reuse such vnodes. These conditions may cause the |
| 387 | * number of vnodes to reach some minimum value regardless of what |
| 388 | * you set kern.maxvnodes to. Do not set kern.maxvnodes too low. |
| 389 | */ |
| 390 | |
| 391 | /* |
| 392 | * This is a quick non-blocking check to determine if the vnode is a good |
| 393 | * candidate for being (eventually) vgone()'d. Returns 0 if the vnode is |
| 394 | * not a good candidate, 1 if it is. |
| 395 | * |
| 396 | * Note that a vnode can be marked VFREE without really being free, so |
| 397 | * we don't use the flag for any tests. |
| 398 | */ |
| 399 | static __inline int |
| 400 | vmightfree(struct vnode *vp, int page_count) |
| 401 | { |
| 402 | if (vp->v_flag & VRECLAIMED) |
| 403 | return (0); |
| 404 | #if 0 |
| 405 | if ((vp->v_flag & VFREE) && TAILQ_EMPTY(&vp->v_namecache)) |
| 406 | return (0); |
| 407 | #endif |
| 408 | if (vp->v_usecount != 0) |
| 409 | return (0); |
| 410 | if (vp->v_object && vp->v_object->resident_page_count >= page_count) |
| 411 | return (0); |
| 412 | return (1); |
| 413 | } |
| 414 | |
| 415 | /* |
| 416 | * The vnode was found to be possibly vgone()able and the caller has locked it |
| 417 | * (thus the usecount should be 1 now). Determine if the vnode is actually |
| 418 | * vgone()able, doing some cleanups in the process. Returns 1 if the vnode |
| 419 | * can be vgone()'d, 0 otherwise. |
| 420 | * |
| 421 | * Note that v_holdcnt may be non-zero because (A) this vnode is not a leaf |
| 422 | * in the namecache topology and (B) this vnode has buffer cache bufs. |
| 423 | * We cannot remove vnodes with non-leaf namecache associations. We do a |
| 424 | * tentitive leaf check prior to attempting to flush out any buffers but the |
| 425 | * 'real' test when all is said in done is that v_holdcnt must become 0 for |
| 426 | * the vnode to be freeable. |
| 427 | * |
| 428 | * We could theoretically just unconditionally flush when v_holdcnt != 0, |
| 429 | * but flushing data associated with non-leaf nodes (which are always |
| 430 | * directories), just throws it away for no benefit. It is the buffer |
| 431 | * cache's responsibility to choose buffers to recycle from the cached |
| 432 | * data point of view. |
| 433 | */ |
| 434 | static int |
| 435 | visleaf(struct vnode *vp) |
| 436 | { |
| 437 | struct namecache *ncp; |
| 438 | |
| 439 | TAILQ_FOREACH(ncp, &vp->v_namecache, nc_vnode) { |
| 440 | if (!TAILQ_EMPTY(&ncp->nc_list)) |
| 441 | return(0); |
| 442 | } |
| 443 | return(1); |
| 444 | } |
| 445 | |
| 446 | /* |
| 447 | * Try to clean up the vnode to the point where it can be vgone()'d, returning |
| 448 | * 0 if it cannot be vgone()'d (or already has been), 1 if it can. Unlike |
| 449 | * vmightfree() this routine may flush the vnode and block. Vnodes marked |
| 450 | * VFREE are still candidates for vgone()ing because they may hold namecache |
| 451 | * resources and could be blocking the namecache directory hierarchy (and |
| 452 | * related vnodes) from being freed. |
| 453 | */ |
| 454 | static int |
| 455 | vtrytomakegoneable(struct vnode *vp, int page_count) |
| 456 | { |
| 457 | if (vp->v_flag & VRECLAIMED) |
| 458 | return (0); |
| 459 | if (vp->v_usecount != 1) |
| 460 | return (0); |
| 461 | if (vp->v_object && vp->v_object->resident_page_count >= page_count) |
| 462 | return (0); |
| 463 | if (vp->v_holdcnt && visleaf(vp)) { |
| 464 | vinvalbuf(vp, V_SAVE, 0, 0); |
| 465 | #if 0 /* DEBUG */ |
| 466 | kprintf((vp->v_holdcnt ? "vrecycle: vp %p failed: %s\n" : |
| 467 | "vrecycle: vp %p succeeded: %s\n"), vp, |
| 468 | (TAILQ_FIRST(&vp->v_namecache) ? |
| 469 | TAILQ_FIRST(&vp->v_namecache)->nc_name : "?")); |
| 470 | #endif |
| 471 | } |
| 472 | return(vp->v_usecount == 1 && vp->v_holdcnt == 0); |
| 473 | } |
| 474 | |
| 475 | /* |
| 476 | * Reclaim up to 1/10 of the vnodes associated with a mount point. Try |
| 477 | * to avoid vnodes which have lots of resident pages (we are trying to free |
| 478 | * vnodes, not memory). |
| 479 | * |
| 480 | * This routine is a callback from the mountlist scan. The mount point |
| 481 | * in question will be busied. |
| 482 | */ |
| 483 | static int |
| 484 | vlrureclaim(struct mount *mp, void *data) |
| 485 | { |
| 486 | struct vnode *vp; |
| 487 | lwkt_tokref ilock; |
| 488 | int done; |
| 489 | int trigger; |
| 490 | int usevnodes; |
| 491 | int count; |
| 492 | int trigger_mult = vnlru_nowhere; |
| 493 | |
| 494 | /* |
| 495 | * Calculate the trigger point for the resident pages check. The |
| 496 | * minimum trigger value is approximately the number of pages in |
| 497 | * the system divded by the number of vnodes. However, due to |
| 498 | * various other system memory overheads unrelated to data caching |
| 499 | * it is a good idea to double the trigger (at least). |
| 500 | * |
| 501 | * trigger_mult starts at 0. If the recycler is having problems |
| 502 | * finding enough freeable vnodes it will increase trigger_mult. |
| 503 | * This should not happen in normal operation, even on machines with |
| 504 | * low amounts of memory, but extraordinary memory use by the system |
| 505 | * verses the amount of cached data can trigger it. |
| 506 | */ |
| 507 | usevnodes = desiredvnodes; |
| 508 | if (usevnodes <= 0) |
| 509 | usevnodes = 1; |
| 510 | trigger = vmstats.v_page_count * (trigger_mult + 2) / usevnodes; |
| 511 | |
| 512 | done = 0; |
| 513 | lwkt_gettoken(&ilock, &mntvnode_token); |
| 514 | count = mp->mnt_nvnodelistsize / 10 + 1; |
| 515 | while (count && (vp = TAILQ_FIRST(&mp->mnt_nvnodelist)) != NULL) { |
| 516 | /* |
| 517 | * __VNODESCAN__ |
| 518 | * |
| 519 | * The VP will stick around while we hold mntvnode_token, |
| 520 | * at least until we block, so we can safely do an initial |
| 521 | * check, and then must check again after we lock the vnode. |
| 522 | */ |
| 523 | if (vp->v_type == VNON || /* XXX */ |
| 524 | vp->v_type == VBAD || /* XXX */ |
| 525 | !vmightfree(vp, trigger) /* critical path opt */ |
| 526 | ) { |
| 527 | vmovevnodetoend(mp, vp); |
| 528 | --count; |
| 529 | continue; |
| 530 | } |
| 531 | |
| 532 | /* |
| 533 | * VX get the candidate vnode. If the VX get fails the |
| 534 | * vnode might still be on the mountlist. Our loop depends |
| 535 | * on us at least cycling the vnode to the end of the |
| 536 | * mountlist. |
| 537 | */ |
| 538 | if (vx_get_nonblock(vp) != 0) { |
| 539 | if (vp->v_mount == mp) |
| 540 | vmovevnodetoend(mp, vp); |
| 541 | --count; |
| 542 | continue; |
| 543 | } |
| 544 | |
| 545 | /* |
| 546 | * Since we blocked locking the vp, make sure it is still |
| 547 | * a candidate for reclamation. That is, it has not already |
| 548 | * been reclaimed and only has our VX reference associated |
| 549 | * with it. |
| 550 | */ |
| 551 | if (vp->v_type == VNON || /* XXX */ |
| 552 | vp->v_type == VBAD || /* XXX */ |
| 553 | (vp->v_flag & VRECLAIMED) || |
| 554 | vp->v_mount != mp || |
| 555 | !vtrytomakegoneable(vp, trigger) /* critical path opt */ |
| 556 | ) { |
| 557 | if (vp->v_mount == mp) |
| 558 | vmovevnodetoend(mp, vp); |
| 559 | --count; |
| 560 | vx_put(vp); |
| 561 | continue; |
| 562 | } |
| 563 | |
| 564 | /* |
| 565 | * All right, we are good, move the vp to the end of the |
| 566 | * mountlist and clean it out. The vget will have returned |
| 567 | * an error if the vnode was destroyed (VRECLAIMED set), so we |
| 568 | * do not have to check again. The vput() will move the |
| 569 | * vnode to the free list if the vgone() was successful. |
| 570 | */ |
| 571 | KKASSERT(vp->v_mount == mp); |
| 572 | vmovevnodetoend(mp, vp); |
| 573 | vgone(vp); |
| 574 | vx_put(vp); |
| 575 | ++done; |
| 576 | --count; |
| 577 | } |
| 578 | lwkt_reltoken(&ilock); |
| 579 | return (done); |
| 580 | } |
| 581 | |
| 582 | /* |
| 583 | * Attempt to recycle vnodes in a context that is always safe to block. |
| 584 | * Calling vlrurecycle() from the bowels of file system code has some |
| 585 | * interesting deadlock problems. |
| 586 | */ |
| 587 | static struct thread *vnlruthread; |
| 588 | static int vnlruproc_sig; |
| 589 | |
| 590 | void |
| 591 | vnlru_proc_wait(void) |
| 592 | { |
| 593 | if (vnlruproc_sig == 0) { |
| 594 | vnlruproc_sig = 1; /* avoid unnecessary wakeups */ |
| 595 | wakeup(vnlruthread); |
| 596 | } |
| 597 | tsleep(&vnlruproc_sig, 0, "vlruwk", hz); |
| 598 | } |
| 599 | |
| 600 | static void |
| 601 | vnlru_proc(void) |
| 602 | { |
| 603 | struct thread *td = curthread; |
| 604 | int done; |
| 605 | |
| 606 | EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc, td, |
| 607 | SHUTDOWN_PRI_FIRST); |
| 608 | |
| 609 | crit_enter(); |
| 610 | for (;;) { |
| 611 | kproc_suspend_loop(); |
| 612 | if (numvnodes - freevnodes <= desiredvnodes * 9 / 10) { |
| 613 | vnlruproc_sig = 0; |
| 614 | wakeup(&vnlruproc_sig); |
| 615 | tsleep(td, 0, "vlruwt", hz); |
| 616 | continue; |
| 617 | } |
| 618 | cache_cleanneg(0); |
| 619 | done = mountlist_scan(vlrureclaim, NULL, MNTSCAN_FORWARD); |
| 620 | |
| 621 | /* |
| 622 | * The vlrureclaim() call only processes 1/10 of the vnodes |
| 623 | * on each mount. If we couldn't find any repeat the loop |
| 624 | * at least enough times to cover all available vnodes before |
| 625 | * we start sleeping. Complain if the failure extends past |
| 626 | * 30 second, every 30 seconds. |
| 627 | */ |
| 628 | if (done == 0) { |
| 629 | ++vnlru_nowhere; |
| 630 | if (vnlru_nowhere % 10 == 0) |
| 631 | tsleep(td, 0, "vlrup", hz * 3); |
| 632 | if (vnlru_nowhere % 100 == 0) |
| 633 | kprintf("vnlru_proc: vnode recycler stopped working!\n"); |
| 634 | if (vnlru_nowhere == 1000) |
| 635 | vnlru_nowhere = 900; |
| 636 | } else { |
| 637 | vnlru_nowhere = 0; |
| 638 | } |
| 639 | } |
| 640 | crit_exit(); |
| 641 | } |
| 642 | |
| 643 | /* |
| 644 | * MOUNTLIST FUNCTIONS |
| 645 | */ |
| 646 | |
| 647 | /* |
| 648 | * mountlist_insert (MP SAFE) |
| 649 | * |
| 650 | * Add a new mount point to the mount list. |
| 651 | */ |
| 652 | void |
| 653 | mountlist_insert(struct mount *mp, int how) |
| 654 | { |
| 655 | lwkt_tokref ilock; |
| 656 | |
| 657 | lwkt_gettoken(&ilock, &mountlist_token); |
| 658 | if (how == MNTINS_FIRST) |
| 659 | TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list); |
| 660 | else |
| 661 | TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); |
| 662 | lwkt_reltoken(&ilock); |
| 663 | } |
| 664 | |
| 665 | /* |
| 666 | * mountlist_interlock (MP SAFE) |
| 667 | * |
| 668 | * Execute the specified interlock function with the mountlist token |
| 669 | * held. The function will be called in a serialized fashion verses |
| 670 | * other functions called through this mechanism. |
| 671 | */ |
| 672 | int |
| 673 | mountlist_interlock(int (*callback)(struct mount *), struct mount *mp) |
| 674 | { |
| 675 | lwkt_tokref ilock; |
| 676 | int error; |
| 677 | |
| 678 | lwkt_gettoken(&ilock, &mountlist_token); |
| 679 | error = callback(mp); |
| 680 | lwkt_reltoken(&ilock); |
| 681 | return (error); |
| 682 | } |
| 683 | |
| 684 | /* |
| 685 | * mountlist_boot_getfirst (DURING BOOT ONLY) |
| 686 | * |
| 687 | * This function returns the first mount on the mountlist, which is |
| 688 | * expected to be the root mount. Since no interlocks are obtained |
| 689 | * this function is only safe to use during booting. |
| 690 | */ |
| 691 | |
| 692 | struct mount * |
| 693 | mountlist_boot_getfirst(void) |
| 694 | { |
| 695 | return(TAILQ_FIRST(&mountlist)); |
| 696 | } |
| 697 | |
| 698 | /* |
| 699 | * mountlist_remove (MP SAFE) |
| 700 | * |
| 701 | * Remove a node from the mountlist. If this node is the next scan node |
| 702 | * for any active mountlist scans, the active mountlist scan will be |
| 703 | * adjusted to skip the node, thus allowing removals during mountlist |
| 704 | * scans. |
| 705 | */ |
| 706 | void |
| 707 | mountlist_remove(struct mount *mp) |
| 708 | { |
| 709 | struct mountscan_info *msi; |
| 710 | lwkt_tokref ilock; |
| 711 | |
| 712 | lwkt_gettoken(&ilock, &mountlist_token); |
| 713 | TAILQ_FOREACH(msi, &mountscan_list, msi_entry) { |
| 714 | if (msi->msi_node == mp) { |
| 715 | if (msi->msi_how & MNTSCAN_FORWARD) |
| 716 | msi->msi_node = TAILQ_NEXT(mp, mnt_list); |
| 717 | else |
| 718 | msi->msi_node = TAILQ_PREV(mp, mntlist, mnt_list); |
| 719 | } |
| 720 | } |
| 721 | TAILQ_REMOVE(&mountlist, mp, mnt_list); |
| 722 | lwkt_reltoken(&ilock); |
| 723 | } |
| 724 | |
| 725 | /* |
| 726 | * mountlist_scan (MP SAFE) |
| 727 | * |
| 728 | * Safely scan the mount points on the mount list. Unless otherwise |
| 729 | * specified each mount point will be busied prior to the callback and |
| 730 | * unbusied afterwords. The callback may safely remove any mount point |
| 731 | * without interfering with the scan. If the current callback |
| 732 | * mount is removed the scanner will not attempt to unbusy it. |
| 733 | * |
| 734 | * If a mount node cannot be busied it is silently skipped. |
| 735 | * |
| 736 | * The callback return value is aggregated and a total is returned. A return |
| 737 | * value of < 0 is not aggregated and will terminate the scan. |
| 738 | * |
| 739 | * MNTSCAN_FORWARD - the mountlist is scanned in the forward direction |
| 740 | * MNTSCAN_REVERSE - the mountlist is scanned in reverse |
| 741 | * MNTSCAN_NOBUSY - the scanner will make the callback without busying |
| 742 | * the mount node. |
| 743 | */ |
| 744 | int |
| 745 | mountlist_scan(int (*callback)(struct mount *, void *), void *data, int how) |
| 746 | { |
| 747 | struct mountscan_info info; |
| 748 | lwkt_tokref ilock; |
| 749 | struct mount *mp; |
| 750 | thread_t td; |
| 751 | int count; |
| 752 | int res; |
| 753 | |
| 754 | lwkt_gettoken(&ilock, &mountlist_token); |
| 755 | |
| 756 | info.msi_how = how; |
| 757 | info.msi_node = NULL; /* paranoia */ |
| 758 | TAILQ_INSERT_TAIL(&mountscan_list, &info, msi_entry); |
| 759 | |
| 760 | res = 0; |
| 761 | td = curthread; |
| 762 | |
| 763 | if (how & MNTSCAN_FORWARD) { |
| 764 | info.msi_node = TAILQ_FIRST(&mountlist); |
| 765 | while ((mp = info.msi_node) != NULL) { |
| 766 | if (how & MNTSCAN_NOBUSY) { |
| 767 | count = callback(mp, data); |
| 768 | } else if (vfs_busy(mp, LK_NOWAIT) == 0) { |
| 769 | count = callback(mp, data); |
| 770 | if (mp == info.msi_node) |
| 771 | vfs_unbusy(mp); |
| 772 | } else { |
| 773 | count = 0; |
| 774 | } |
| 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 | if (how & MNTSCAN_NOBUSY) { |
| 785 | count = callback(mp, data); |
| 786 | } else if (vfs_busy(mp, LK_NOWAIT) == 0) { |
| 787 | count = callback(mp, data); |
| 788 | if (mp == info.msi_node) |
| 789 | vfs_unbusy(mp); |
| 790 | } else { |
| 791 | count = 0; |
| 792 | } |
| 793 | if (count < 0) |
| 794 | break; |
| 795 | res += count; |
| 796 | if (mp == info.msi_node) |
| 797 | info.msi_node = TAILQ_PREV(mp, mntlist, mnt_list); |
| 798 | } |
| 799 | } |
| 800 | TAILQ_REMOVE(&mountscan_list, &info, msi_entry); |
| 801 | lwkt_reltoken(&ilock); |
| 802 | return(res); |
| 803 | } |
| 804 | |
| 805 | /* |
| 806 | * MOUNT RELATED VNODE FUNCTIONS |
| 807 | */ |
| 808 | |
| 809 | static struct kproc_desc vnlru_kp = { |
| 810 | "vnlru", |
| 811 | vnlru_proc, |
| 812 | &vnlruthread |
| 813 | }; |
| 814 | SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp) |
| 815 | |
| 816 | /* |
| 817 | * Move a vnode from one mount queue to another. |
| 818 | */ |
| 819 | void |
| 820 | insmntque(struct vnode *vp, struct mount *mp) |
| 821 | { |
| 822 | lwkt_tokref ilock; |
| 823 | |
| 824 | lwkt_gettoken(&ilock, &mntvnode_token); |
| 825 | /* |
| 826 | * Delete from old mount point vnode list, if on one. |
| 827 | */ |
| 828 | if (vp->v_mount != NULL) { |
| 829 | KASSERT(vp->v_mount->mnt_nvnodelistsize > 0, |
| 830 | ("bad mount point vnode list size")); |
| 831 | vremovevnodemnt(vp); |
| 832 | vp->v_mount->mnt_nvnodelistsize--; |
| 833 | } |
| 834 | /* |
| 835 | * Insert into list of vnodes for the new mount point, if available. |
| 836 | */ |
| 837 | if ((vp->v_mount = mp) == NULL) { |
| 838 | lwkt_reltoken(&ilock); |
| 839 | return; |
| 840 | } |
| 841 | TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes); |
| 842 | mp->mnt_nvnodelistsize++; |
| 843 | lwkt_reltoken(&ilock); |
| 844 | } |
| 845 | |
| 846 | |
| 847 | /* |
| 848 | * Scan the vnodes under a mount point and issue appropriate callbacks. |
| 849 | * |
| 850 | * The fastfunc() callback is called with just the mountlist token held |
| 851 | * (no vnode lock). It may not block and the vnode may be undergoing |
| 852 | * modifications while the caller is processing it. The vnode will |
| 853 | * not be entirely destroyed, however, due to the fact that the mountlist |
| 854 | * token is held. A return value < 0 skips to the next vnode without calling |
| 855 | * the slowfunc(), a return value > 0 terminates the loop. |
| 856 | * |
| 857 | * The slowfunc() callback is called after the vnode has been successfully |
| 858 | * locked based on passed flags. The vnode is skipped if it gets rearranged |
| 859 | * or destroyed while blocking on the lock. A non-zero return value from |
| 860 | * the slow function terminates the loop. The slow function is allowed to |
| 861 | * arbitrarily block. The scanning code guarentees consistency of operation |
| 862 | * even if the slow function deletes or moves the node, or blocks and some |
| 863 | * other thread deletes or moves the node. |
| 864 | */ |
| 865 | int |
| 866 | vmntvnodescan( |
| 867 | struct mount *mp, |
| 868 | int flags, |
| 869 | int (*fastfunc)(struct mount *mp, struct vnode *vp, void *data), |
| 870 | int (*slowfunc)(struct mount *mp, struct vnode *vp, void *data), |
| 871 | void *data |
| 872 | ) { |
| 873 | struct vmntvnodescan_info info; |
| 874 | lwkt_tokref ilock; |
| 875 | struct vnode *vp; |
| 876 | int r = 0; |
| 877 | int maxcount = 1000000; |
| 878 | |
| 879 | lwkt_gettoken(&ilock, &mntvnode_token); |
| 880 | |
| 881 | info.vp = TAILQ_FIRST(&mp->mnt_nvnodelist); |
| 882 | TAILQ_INSERT_TAIL(&mntvnodescan_list, &info, entry); |
| 883 | while ((vp = info.vp) != NULL) { |
| 884 | if (--maxcount == 0) |
| 885 | panic("maxcount reached during vmntvnodescan"); |
| 886 | |
| 887 | if (vp->v_type == VNON) /* visible but not ready */ |
| 888 | goto next; |
| 889 | KKASSERT(vp->v_mount == mp); |
| 890 | |
| 891 | /* |
| 892 | * Quick test. A negative return continues the loop without |
| 893 | * calling the slow test. 0 continues onto the slow test. |
| 894 | * A positive number aborts the loop. |
| 895 | */ |
| 896 | if (fastfunc) { |
| 897 | if ((r = fastfunc(mp, vp, data)) < 0) |
| 898 | goto next; |
| 899 | if (r) |
| 900 | break; |
| 901 | } |
| 902 | |
| 903 | /* |
| 904 | * Get a vxlock on the vnode, retry if it has moved or isn't |
| 905 | * in the mountlist where we expect it. |
| 906 | */ |
| 907 | if (slowfunc) { |
| 908 | int error; |
| 909 | |
| 910 | switch(flags) { |
| 911 | case VMSC_GETVP: |
| 912 | error = vget(vp, LK_EXCLUSIVE); |
| 913 | break; |
| 914 | case VMSC_GETVP|VMSC_NOWAIT: |
| 915 | error = vget(vp, LK_EXCLUSIVE|LK_NOWAIT); |
| 916 | break; |
| 917 | case VMSC_GETVX: |
| 918 | vx_get(vp); |
| 919 | error = 0; |
| 920 | break; |
| 921 | default: |
| 922 | error = 0; |
| 923 | break; |
| 924 | } |
| 925 | if (error) |
| 926 | goto next; |
| 927 | /* |
| 928 | * Do not call the slow function if the vnode is |
| 929 | * invalid or if it was ripped out from under us |
| 930 | * while we (potentially) blocked. |
| 931 | */ |
| 932 | if (info.vp == vp && vp->v_type != VNON) |
| 933 | r = slowfunc(mp, vp, data); |
| 934 | |
| 935 | /* |
| 936 | * Cleanup |
| 937 | */ |
| 938 | switch(flags) { |
| 939 | case VMSC_GETVP: |
| 940 | case VMSC_GETVP|VMSC_NOWAIT: |
| 941 | vput(vp); |
| 942 | break; |
| 943 | case VMSC_GETVX: |
| 944 | vx_put(vp); |
| 945 | break; |
| 946 | default: |
| 947 | break; |
| 948 | } |
| 949 | if (r != 0) |
| 950 | break; |
| 951 | } |
| 952 | |
| 953 | /* |
| 954 | * Iterate. If the vnode was ripped out from under us |
| 955 | * info.vp will already point to the next vnode, otherwise |
| 956 | * we have to obtain the next valid vnode ourselves. |
| 957 | */ |
| 958 | next: |
| 959 | if (info.vp == vp) |
| 960 | info.vp = TAILQ_NEXT(vp, v_nmntvnodes); |
| 961 | } |
| 962 | TAILQ_REMOVE(&mntvnodescan_list, &info, entry); |
| 963 | lwkt_reltoken(&ilock); |
| 964 | return(r); |
| 965 | } |
| 966 | |
| 967 | /* |
| 968 | * Remove any vnodes in the vnode table belonging to mount point mp. |
| 969 | * |
| 970 | * If FORCECLOSE is not specified, there should not be any active ones, |
| 971 | * return error if any are found (nb: this is a user error, not a |
| 972 | * system error). If FORCECLOSE is specified, detach any active vnodes |
| 973 | * that are found. |
| 974 | * |
| 975 | * If WRITECLOSE is set, only flush out regular file vnodes open for |
| 976 | * writing. |
| 977 | * |
| 978 | * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped. |
| 979 | * |
| 980 | * `rootrefs' specifies the base reference count for the root vnode |
| 981 | * of this filesystem. The root vnode is considered busy if its |
| 982 | * v_usecount exceeds this value. On a successful return, vflush() |
| 983 | * will call vrele() on the root vnode exactly rootrefs times. |
| 984 | * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must |
| 985 | * be zero. |
| 986 | */ |
| 987 | #ifdef DIAGNOSTIC |
| 988 | static int busyprt = 0; /* print out busy vnodes */ |
| 989 | SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, ""); |
| 990 | #endif |
| 991 | |
| 992 | static int vflush_scan(struct mount *mp, struct vnode *vp, void *data); |
| 993 | |
| 994 | struct vflush_info { |
| 995 | int flags; |
| 996 | int busy; |
| 997 | thread_t td; |
| 998 | }; |
| 999 | |
| 1000 | int |
| 1001 | vflush(struct mount *mp, int rootrefs, int flags) |
| 1002 | { |
| 1003 | struct thread *td = curthread; /* XXX */ |
| 1004 | struct vnode *rootvp = NULL; |
| 1005 | int error; |
| 1006 | struct vflush_info vflush_info; |
| 1007 | |
| 1008 | if (rootrefs > 0) { |
| 1009 | KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0, |
| 1010 | ("vflush: bad args")); |
| 1011 | /* |
| 1012 | * Get the filesystem root vnode. We can vput() it |
| 1013 | * immediately, since with rootrefs > 0, it won't go away. |
| 1014 | */ |
| 1015 | if ((error = VFS_ROOT(mp, &rootvp)) != 0) |
| 1016 | return (error); |
| 1017 | vput(rootvp); |
| 1018 | } |
| 1019 | |
| 1020 | vflush_info.busy = 0; |
| 1021 | vflush_info.flags = flags; |
| 1022 | vflush_info.td = td; |
| 1023 | vmntvnodescan(mp, VMSC_GETVX, NULL, vflush_scan, &vflush_info); |
| 1024 | |
| 1025 | if (rootrefs > 0 && (flags & FORCECLOSE) == 0) { |
| 1026 | /* |
| 1027 | * If just the root vnode is busy, and if its refcount |
| 1028 | * is equal to `rootrefs', then go ahead and kill it. |
| 1029 | */ |
| 1030 | KASSERT(vflush_info.busy > 0, ("vflush: not busy")); |
| 1031 | KASSERT(rootvp->v_usecount >= rootrefs, ("vflush: rootrefs")); |
| 1032 | if (vflush_info.busy == 1 && rootvp->v_usecount == rootrefs) { |
| 1033 | vx_lock(rootvp); |
| 1034 | vgone(rootvp); |
| 1035 | vx_unlock(rootvp); |
| 1036 | vflush_info.busy = 0; |
| 1037 | } |
| 1038 | } |
| 1039 | if (vflush_info.busy) |
| 1040 | return (EBUSY); |
| 1041 | for (; rootrefs > 0; rootrefs--) |
| 1042 | vrele(rootvp); |
| 1043 | return (0); |
| 1044 | } |
| 1045 | |
| 1046 | /* |
| 1047 | * The scan callback is made with an VX locked vnode. |
| 1048 | */ |
| 1049 | static int |
| 1050 | vflush_scan(struct mount *mp, struct vnode *vp, void *data) |
| 1051 | { |
| 1052 | struct vflush_info *info = data; |
| 1053 | struct vattr vattr; |
| 1054 | |
| 1055 | /* |
| 1056 | * Skip over a vnodes marked VSYSTEM. |
| 1057 | */ |
| 1058 | if ((info->flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) { |
| 1059 | return(0); |
| 1060 | } |
| 1061 | |
| 1062 | /* |
| 1063 | * If WRITECLOSE is set, flush out unlinked but still open |
| 1064 | * files (even if open only for reading) and regular file |
| 1065 | * vnodes open for writing. |
| 1066 | */ |
| 1067 | if ((info->flags & WRITECLOSE) && |
| 1068 | (vp->v_type == VNON || |
| 1069 | (VOP_GETATTR(vp, &vattr) == 0 && |
| 1070 | vattr.va_nlink > 0)) && |
| 1071 | (vp->v_writecount == 0 || vp->v_type != VREG)) { |
| 1072 | return(0); |
| 1073 | } |
| 1074 | |
| 1075 | /* |
| 1076 | * With v_usecount == 0, all we need to do is clear out the |
| 1077 | * vnode data structures and we are done. |
| 1078 | */ |
| 1079 | if (vp->v_usecount == 1) { |
| 1080 | vgone(vp); |
| 1081 | return(0); |
| 1082 | } |
| 1083 | |
| 1084 | /* |
| 1085 | * If FORCECLOSE is set, forcibly close the vnode. For block |
| 1086 | * or character devices, revert to an anonymous device. For |
| 1087 | * all other files, just kill them. |
| 1088 | */ |
| 1089 | if (info->flags & FORCECLOSE) { |
| 1090 | if (vp->v_type != VBLK && vp->v_type != VCHR) { |
| 1091 | vgone(vp); |
| 1092 | } else { |
| 1093 | spin_lock_wr(&vp->v_spinlock); |
| 1094 | vclean_interlocked(vp, 0); |
| 1095 | /* spinlock unlocked */ |
| 1096 | vp->v_ops = &spec_vnode_vops_p; |
| 1097 | insmntque(vp, NULL); |
| 1098 | } |
| 1099 | return(0); |
| 1100 | } |
| 1101 | #ifdef DIAGNOSTIC |
| 1102 | if (busyprt) |
| 1103 | vprint("vflush: busy vnode", vp); |
| 1104 | #endif |
| 1105 | ++info->busy; |
| 1106 | return(0); |
| 1107 | } |
| 1108 | |