The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_subr.c

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    1 /*
    2  * Copyright (c) 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 3. All advertising materials mentioning features or use of this software
   19  *    must display the following acknowledgement:
   20  *      This product includes software developed by the University of
   21  *      California, Berkeley and its contributors.
   22  * 4. Neither the name of the University nor the names of its contributors
   23  *    may be used to endorse or promote products derived from this software
   24  *    without specific prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   36  * SUCH DAMAGE.
   37  *
   38  *      @(#)vfs_subr.c  8.31 (Berkeley) 5/26/95
   39  * $FreeBSD: releng/5.0/sys/kern/vfs_subr.c 108561 2003-01-02 19:56:45Z phk $
   40  */
   41 
   42 /*
   43  * External virtual filesystem routines
   44  */
   45 #include "opt_ddb.h"
   46 #include "opt_mac.h"
   47 
   48 #include <sys/param.h>
   49 #include <sys/systm.h>
   50 #include <sys/bio.h>
   51 #include <sys/buf.h>
   52 #include <sys/conf.h>
   53 #include <sys/eventhandler.h>
   54 #include <sys/extattr.h>
   55 #include <sys/fcntl.h>
   56 #include <sys/kernel.h>
   57 #include <sys/kthread.h>
   58 #include <sys/mac.h>
   59 #include <sys/malloc.h>
   60 #include <sys/mount.h>
   61 #include <sys/namei.h>
   62 #include <sys/stat.h>
   63 #include <sys/sysctl.h>
   64 #include <sys/syslog.h>
   65 #include <sys/vmmeter.h>
   66 #include <sys/vnode.h>
   67 
   68 #include <vm/vm.h>
   69 #include <vm/vm_object.h>
   70 #include <vm/vm_extern.h>
   71 #include <vm/pmap.h>
   72 #include <vm/vm_map.h>
   73 #include <vm/vm_page.h>
   74 #include <vm/uma.h>
   75 
   76 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
   77 
   78 static void     addalias(struct vnode *vp, dev_t nvp_rdev);
   79 static void     insmntque(struct vnode *vp, struct mount *mp);
   80 static void     vclean(struct vnode *vp, int flags, struct thread *td);
   81 static void     vlruvp(struct vnode *vp);
   82 static int      flushbuflist(struct buf *blist, int flags, struct vnode *vp,
   83                     int slpflag, int slptimeo, int *errorp);
   84 static int      vcanrecycle(struct vnode *vp, struct mount **vnmpp);
   85 
   86 
   87 /*
   88  * Number of vnodes in existence.  Increased whenever getnewvnode()
   89  * allocates a new vnode, never decreased.
   90  */
   91 static unsigned long    numvnodes;
   92 
   93 SYSCTL_LONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
   94 
   95 /*
   96  * Conversion tables for conversion from vnode types to inode formats
   97  * and back.
   98  */
   99 enum vtype iftovt_tab[16] = {
  100         VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
  101         VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
  102 };
  103 int vttoif_tab[9] = {
  104         0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
  105         S_IFSOCK, S_IFIFO, S_IFMT,
  106 };
  107 
  108 /*
  109  * List of vnodes that are ready for recycling.
  110  */
  111 static TAILQ_HEAD(freelst, vnode) vnode_free_list;
  112 
  113 /*
  114  * Minimum number of free vnodes.  If there are fewer than this free vnodes,
  115  * getnewvnode() will return a newly allocated vnode.
  116  */
  117 static u_long wantfreevnodes = 25;
  118 SYSCTL_LONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
  119 /* Number of vnodes in the free list. */
  120 static u_long freevnodes;
  121 SYSCTL_LONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "");
  122 
  123 /*
  124  * Various variables used for debugging the new implementation of
  125  * reassignbuf().
  126  * XXX these are probably of (very) limited utility now.
  127  */
  128 static int reassignbufcalls;
  129 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0, "");
  130 static int nameileafonly;
  131 SYSCTL_INT(_vfs, OID_AUTO, nameileafonly, CTLFLAG_RW, &nameileafonly, 0, "");
  132 
  133 #ifdef ENABLE_VFS_IOOPT
  134 /* See NOTES for a description of this setting. */
  135 int vfs_ioopt;
  136 SYSCTL_INT(_vfs, OID_AUTO, ioopt, CTLFLAG_RW, &vfs_ioopt, 0, "");
  137 #endif
  138 
  139 /*
  140  * Cache for the mount type id assigned to NFS.  This is used for
  141  * special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
  142  */
  143 int     nfs_mount_type = -1;
  144 
  145 /* To keep more than one thread at a time from running vfs_getnewfsid */
  146 static struct mtx mntid_mtx;
  147 
  148 /*
  149  * Lock for any access to the following:
  150  *      vnode_free_list
  151  *      numvnodes
  152  *      freevnodes
  153  */
  154 static struct mtx vnode_free_list_mtx;
  155 
  156 /*
  157  * For any iteration/modification of dev->si_hlist (linked through
  158  * v_specnext)
  159  */
  160 static struct mtx spechash_mtx;
  161 
  162 /* Publicly exported FS */
  163 struct nfs_public nfs_pub;
  164 
  165 /* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
  166 static uma_zone_t vnode_zone;
  167 static uma_zone_t vnodepoll_zone;
  168 
  169 /* Set to 1 to print out reclaim of active vnodes */
  170 int     prtactive;
  171 
  172 /*
  173  * The workitem queue.
  174  *
  175  * It is useful to delay writes of file data and filesystem metadata
  176  * for tens of seconds so that quickly created and deleted files need
  177  * not waste disk bandwidth being created and removed. To realize this,
  178  * we append vnodes to a "workitem" queue. When running with a soft
  179  * updates implementation, most pending metadata dependencies should
  180  * not wait for more than a few seconds. Thus, mounted on block devices
  181  * are delayed only about a half the time that file data is delayed.
  182  * Similarly, directory updates are more critical, so are only delayed
  183  * about a third the time that file data is delayed. Thus, there are
  184  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
  185  * one each second (driven off the filesystem syncer process). The
  186  * syncer_delayno variable indicates the next queue that is to be processed.
  187  * Items that need to be processed soon are placed in this queue:
  188  *
  189  *      syncer_workitem_pending[syncer_delayno]
  190  *
  191  * A delay of fifteen seconds is done by placing the request fifteen
  192  * entries later in the queue:
  193  *
  194  *      syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
  195  *
  196  */
  197 static int syncer_delayno;
  198 static long syncer_mask;
  199 LIST_HEAD(synclist, vnode);
  200 static struct synclist *syncer_workitem_pending;
  201 /*
  202  * The sync_mtx protects:
  203  *      vp->v_synclist
  204  *      syncer_delayno
  205  *      syncer_workitem_pending
  206  *      rushjob
  207  */
  208 static struct mtx sync_mtx;
  209 
  210 #define SYNCER_MAXDELAY         32
  211 static int syncer_maxdelay = SYNCER_MAXDELAY;   /* maximum delay time */
  212 static int syncdelay = 30;              /* max time to delay syncing data */
  213 static int filedelay = 30;              /* time to delay syncing files */
  214 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "");
  215 static int dirdelay = 29;               /* time to delay syncing directories */
  216 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "");
  217 static int metadelay = 28;              /* time to delay syncing metadata */
  218 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "");
  219 static int rushjob;             /* number of slots to run ASAP */
  220 static int stat_rush_requests;  /* number of times I/O speeded up */
  221 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0, "");
  222 
  223 /*
  224  * Number of vnodes we want to exist at any one time.  This is mostly used
  225  * to size hash tables in vnode-related code.  It is normally not used in
  226  * getnewvnode(), as wantfreevnodes is normally nonzero.)
  227  *
  228  * XXX desiredvnodes is historical cruft and should not exist.
  229  */
  230 int desiredvnodes;
  231 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
  232     &desiredvnodes, 0, "Maximum number of vnodes");
  233 static int minvnodes;
  234 SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
  235     &minvnodes, 0, "Minimum number of vnodes");
  236 static int vnlru_nowhere;
  237 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW, &vnlru_nowhere, 0,
  238     "Number of times the vnlru process ran without success");
  239 
  240 /* Hook for calling soft updates */
  241 int (*softdep_process_worklist_hook)(struct mount *);
  242 
  243 /*
  244  * This only exists to supress warnings from unlocked specfs accesses.  It is
  245  * no longer ok to have an unlocked VFS.
  246  */
  247 #define IGNORE_LOCK(vp) ((vp)->v_type == VCHR || (vp)->v_type == VBAD)
  248 
  249 /* Print lock violations */
  250 int vfs_badlock_print = 1;
  251 
  252 /* Panic on violation */
  253 int vfs_badlock_panic = 1;
  254 
  255 /* Check for interlock across VOPs */
  256 int vfs_badlock_mutex = 1;
  257 
  258 static void
  259 vfs_badlock(char *msg, char *str, struct vnode *vp)
  260 {
  261         if (vfs_badlock_print)
  262                 printf("%s: %p %s\n", str, vp, msg);
  263         if (vfs_badlock_panic)
  264                 Debugger("Lock violation.\n");
  265 }
  266 
  267 void
  268 assert_vi_unlocked(struct vnode *vp, char *str)
  269 { 
  270         if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
  271                 vfs_badlock("interlock is locked but should not be", str, vp);
  272 }
  273 
  274 void
  275 assert_vi_locked(struct vnode *vp, char *str)
  276 {
  277         if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
  278                 vfs_badlock("interlock is not locked but should be", str, vp);
  279 }
  280 
  281 void
  282 assert_vop_locked(struct vnode *vp, char *str)
  283 {
  284         if (vp && !IGNORE_LOCK(vp) && !VOP_ISLOCKED(vp, NULL))
  285                 vfs_badlock("is not locked but should be", str, vp);
  286 }
  287 
  288 void
  289 assert_vop_unlocked(struct vnode *vp, char *str)
  290 {
  291         if (vp && !IGNORE_LOCK(vp) &&
  292             VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE)
  293                 vfs_badlock("is locked but should not be", str, vp);
  294 }
  295 
  296 void
  297 assert_vop_elocked(struct vnode *vp, char *str)
  298 {
  299         if (vp && !IGNORE_LOCK(vp) &&
  300             VOP_ISLOCKED(vp, curthread) != LK_EXCLUSIVE)
  301                 vfs_badlock("is not exclusive locked but should be", str, vp);
  302 }
  303 
  304 void
  305 assert_vop_elocked_other(struct vnode *vp, char *str)
  306 {
  307         if (vp && !IGNORE_LOCK(vp) &&
  308             VOP_ISLOCKED(vp, curthread) != LK_EXCLOTHER)
  309                 vfs_badlock("is not exclusive locked by another thread",
  310                     str, vp);
  311 }
  312 
  313 void
  314 assert_vop_slocked(struct vnode *vp, char *str)
  315 {
  316         if (vp && !IGNORE_LOCK(vp) &&
  317             VOP_ISLOCKED(vp, curthread) != LK_SHARED)
  318                 vfs_badlock("is not locked shared but should be", str, vp);
  319 }
  320 
  321 void
  322 vop_rename_pre(void *ap)
  323 {
  324         struct vop_rename_args *a = ap;
  325 
  326         if (a->a_tvp)
  327                 ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
  328         ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
  329         ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
  330         ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
  331 
  332         /* Check the source (from) */
  333         if (a->a_tdvp != a->a_fdvp)
  334                 ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked.\n");
  335         if (a->a_tvp != a->a_fvp)
  336                 ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: tvp locked.\n");
  337 
  338         /* Check the target */
  339         if (a->a_tvp)
  340                 ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked.\n");
  341 
  342         ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked.\n");
  343 }
  344 
  345 void
  346 vop_strategy_pre(void *ap)
  347 {
  348         struct vop_strategy_args *a = ap;
  349         struct buf *bp;
  350 
  351         bp = a->a_bp;
  352 
  353         /*
  354          * Cluster ops lock their component buffers but not the IO container.
  355          */
  356         if ((bp->b_flags & B_CLUSTER) != 0)
  357                 return;
  358 
  359         if (BUF_REFCNT(bp) < 1) {
  360                 if (vfs_badlock_print)
  361                         printf("VOP_STRATEGY: bp is not locked but should be.\n");
  362                 if (vfs_badlock_panic)
  363                         Debugger("Lock violation.\n");
  364         }
  365 }
  366 
  367 void
  368 vop_lookup_pre(void *ap)
  369 {
  370         struct vop_lookup_args *a = ap;
  371         struct vnode *dvp;
  372 
  373         dvp = a->a_dvp;
  374 
  375         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
  376         ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
  377 }
  378 
  379 void
  380 vop_lookup_post(void *ap, int rc)
  381 {
  382         struct vop_lookup_args *a = ap;
  383         struct componentname *cnp;
  384         struct vnode *dvp;
  385         struct vnode *vp;
  386         int flags;
  387 
  388         dvp = a->a_dvp;
  389         cnp = a->a_cnp;
  390         vp = *(a->a_vpp);
  391         flags = cnp->cn_flags;
  392 
  393 
  394         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
  395         /*
  396          * If this is the last path component for this lookup and LOCPARENT
  397          * is set, OR if there is an error the directory has to be locked.
  398          */
  399         if ((flags & LOCKPARENT) && (flags & ISLASTCN))
  400                 ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP (LOCKPARENT)");
  401         else if (rc != 0)
  402                 ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP (error)");
  403         else if (dvp != vp)
  404                 ASSERT_VOP_UNLOCKED(dvp, "VOP_LOOKUP (dvp)");
  405 
  406         if (flags & PDIRUNLOCK)
  407                 ASSERT_VOP_UNLOCKED(dvp, "VOP_LOOKUP (PDIRUNLOCK)");
  408 }
  409 
  410 void
  411 vop_unlock_pre(void *ap)
  412 {
  413         struct vop_unlock_args *a = ap;
  414 
  415         if (a->a_flags & LK_INTERLOCK)
  416                 ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
  417 
  418         ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
  419 }
  420 
  421 void
  422 vop_unlock_post(void *ap, int rc)
  423 {
  424         struct vop_unlock_args *a = ap;
  425 
  426         if (a->a_flags & LK_INTERLOCK)
  427                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
  428 }
  429 
  430 void
  431 vop_lock_pre(void *ap)
  432 {
  433         struct vop_lock_args *a = ap;
  434 
  435         if ((a->a_flags & LK_INTERLOCK) == 0)
  436                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
  437         else
  438                 ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
  439 }
  440 
  441 void
  442 vop_lock_post(void *ap, int rc)
  443 {
  444         struct vop_lock_args *a;
  445 
  446         a = ap;
  447 
  448         ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
  449         ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
  450 }
  451 
  452 void
  453 v_addpollinfo(struct vnode *vp)
  454 {
  455         vp->v_pollinfo = uma_zalloc(vnodepoll_zone, M_WAITOK);
  456         mtx_init(&vp->v_pollinfo->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
  457 }
  458 
  459 /*
  460  * Initialize the vnode management data structures.
  461  */
  462 static void
  463 vntblinit(void *dummy __unused)
  464 {
  465 
  466         desiredvnodes = maxproc + cnt.v_page_count / 4;
  467         minvnodes = desiredvnodes / 4;
  468         mtx_init(&mountlist_mtx, "mountlist", NULL, MTX_DEF);
  469         mtx_init(&mntvnode_mtx, "mntvnode", NULL, MTX_DEF);
  470         mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
  471         mtx_init(&spechash_mtx, "spechash", NULL, MTX_DEF);
  472         TAILQ_INIT(&vnode_free_list);
  473         mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
  474         vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
  475             NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  476         vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
  477               NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  478         /*
  479          * Initialize the filesystem syncer.
  480          */
  481         syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE,
  482                 &syncer_mask);
  483         syncer_maxdelay = syncer_mask + 1;
  484         mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
  485 }
  486 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL)
  487 
  488 
  489 /*
  490  * Mark a mount point as busy. Used to synchronize access and to delay
  491  * unmounting. Interlock is not released on failure.
  492  */
  493 int
  494 vfs_busy(mp, flags, interlkp, td)
  495         struct mount *mp;
  496         int flags;
  497         struct mtx *interlkp;
  498         struct thread *td;
  499 {
  500         int lkflags;
  501 
  502         if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
  503                 if (flags & LK_NOWAIT)
  504                         return (ENOENT);
  505                 mp->mnt_kern_flag |= MNTK_MWAIT;
  506                 /*
  507                  * Since all busy locks are shared except the exclusive
  508                  * lock granted when unmounting, the only place that a
  509                  * wakeup needs to be done is at the release of the
  510                  * exclusive lock at the end of dounmount.
  511                  */
  512                 msleep(mp, interlkp, PVFS, "vfs_busy", 0);
  513                 return (ENOENT);
  514         }
  515         lkflags = LK_SHARED | LK_NOPAUSE;
  516         if (interlkp)
  517                 lkflags |= LK_INTERLOCK;
  518         if (lockmgr(&mp->mnt_lock, lkflags, interlkp, td))
  519                 panic("vfs_busy: unexpected lock failure");
  520         return (0);
  521 }
  522 
  523 /*
  524  * Free a busy filesystem.
  525  */
  526 void
  527 vfs_unbusy(mp, td)
  528         struct mount *mp;
  529         struct thread *td;
  530 {
  531 
  532         lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
  533 }
  534 
  535 /*
  536  * Lookup a mount point by filesystem identifier.
  537  */
  538 struct mount *
  539 vfs_getvfs(fsid)
  540         fsid_t *fsid;
  541 {
  542         register struct mount *mp;
  543 
  544         mtx_lock(&mountlist_mtx);
  545         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  546                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  547                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  548                         mtx_unlock(&mountlist_mtx);
  549                         return (mp);
  550                 }
  551         }
  552         mtx_unlock(&mountlist_mtx);
  553         return ((struct mount *) 0);
  554 }
  555 
  556 /*
  557  * Get a new unique fsid.  Try to make its val[0] unique, since this value
  558  * will be used to create fake device numbers for stat().  Also try (but
  559  * not so hard) make its val[0] unique mod 2^16, since some emulators only
  560  * support 16-bit device numbers.  We end up with unique val[0]'s for the
  561  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
  562  *
  563  * Keep in mind that several mounts may be running in parallel.  Starting
  564  * the search one past where the previous search terminated is both a
  565  * micro-optimization and a defense against returning the same fsid to
  566  * different mounts.
  567  */
  568 void
  569 vfs_getnewfsid(mp)
  570         struct mount *mp;
  571 {
  572         static u_int16_t mntid_base;
  573         fsid_t tfsid;
  574         int mtype;
  575 
  576         mtx_lock(&mntid_mtx);
  577         mtype = mp->mnt_vfc->vfc_typenum;
  578         tfsid.val[1] = mtype;
  579         mtype = (mtype & 0xFF) << 24;
  580         for (;;) {
  581                 tfsid.val[0] = makeudev(255,
  582                     mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
  583                 mntid_base++;
  584                 if (vfs_getvfs(&tfsid) == NULL)
  585                         break;
  586         }
  587         mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
  588         mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
  589         mtx_unlock(&mntid_mtx);
  590 }
  591 
  592 /*
  593  * Knob to control the precision of file timestamps:
  594  *
  595  *   0 = seconds only; nanoseconds zeroed.
  596  *   1 = seconds and nanoseconds, accurate within 1/HZ.
  597  *   2 = seconds and nanoseconds, truncated to microseconds.
  598  * >=3 = seconds and nanoseconds, maximum precision.
  599  */
  600 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
  601 
  602 static int timestamp_precision = TSP_SEC;
  603 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
  604     &timestamp_precision, 0, "");
  605 
  606 /*
  607  * Get a current timestamp.
  608  */
  609 void
  610 vfs_timestamp(tsp)
  611         struct timespec *tsp;
  612 {
  613         struct timeval tv;
  614 
  615         switch (timestamp_precision) {
  616         case TSP_SEC:
  617                 tsp->tv_sec = time_second;
  618                 tsp->tv_nsec = 0;
  619                 break;
  620         case TSP_HZ:
  621                 getnanotime(tsp);
  622                 break;
  623         case TSP_USEC:
  624                 microtime(&tv);
  625                 TIMEVAL_TO_TIMESPEC(&tv, tsp);
  626                 break;
  627         case TSP_NSEC:
  628         default:
  629                 nanotime(tsp);
  630                 break;
  631         }
  632 }
  633 
  634 /*
  635  * Set vnode attributes to VNOVAL
  636  */
  637 void
  638 vattr_null(vap)
  639         register struct vattr *vap;
  640 {
  641 
  642         vap->va_type = VNON;
  643         vap->va_size = VNOVAL;
  644         vap->va_bytes = VNOVAL;
  645         vap->va_mode = VNOVAL;
  646         vap->va_nlink = VNOVAL;
  647         vap->va_uid = VNOVAL;
  648         vap->va_gid = VNOVAL;
  649         vap->va_fsid = VNOVAL;
  650         vap->va_fileid = VNOVAL;
  651         vap->va_blocksize = VNOVAL;
  652         vap->va_rdev = VNOVAL;
  653         vap->va_atime.tv_sec = VNOVAL;
  654         vap->va_atime.tv_nsec = VNOVAL;
  655         vap->va_mtime.tv_sec = VNOVAL;
  656         vap->va_mtime.tv_nsec = VNOVAL;
  657         vap->va_ctime.tv_sec = VNOVAL;
  658         vap->va_ctime.tv_nsec = VNOVAL;
  659         vap->va_birthtime.tv_sec = VNOVAL;
  660         vap->va_birthtime.tv_nsec = VNOVAL;
  661         vap->va_flags = VNOVAL;
  662         vap->va_gen = VNOVAL;
  663         vap->va_vaflags = 0;
  664 }
  665 
  666 /*
  667  * This routine is called when we have too many vnodes.  It attempts
  668  * to free <count> vnodes and will potentially free vnodes that still
  669  * have VM backing store (VM backing store is typically the cause
  670  * of a vnode blowout so we want to do this).  Therefore, this operation
  671  * is not considered cheap.
  672  *
  673  * A number of conditions may prevent a vnode from being reclaimed.
  674  * the buffer cache may have references on the vnode, a directory
  675  * vnode may still have references due to the namei cache representing
  676  * underlying files, or the vnode may be in active use.   It is not
  677  * desireable to reuse such vnodes.  These conditions may cause the
  678  * number of vnodes to reach some minimum value regardless of what
  679  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
  680  */
  681 static int
  682 vlrureclaim(struct mount *mp, int count)
  683 {
  684         struct vnode *vp;
  685         int done;
  686         int trigger;
  687         int usevnodes;
  688 
  689         /*
  690          * Calculate the trigger point, don't allow user
  691          * screwups to blow us up.   This prevents us from
  692          * recycling vnodes with lots of resident pages.  We
  693          * aren't trying to free memory, we are trying to
  694          * free vnodes.
  695          */
  696         usevnodes = desiredvnodes;
  697         if (usevnodes <= 0)
  698                 usevnodes = 1;
  699         trigger = cnt.v_page_count * 2 / usevnodes;
  700 
  701         done = 0;
  702         mtx_lock(&mntvnode_mtx);
  703         while (count && (vp = TAILQ_FIRST(&mp->mnt_nvnodelist)) != NULL) {
  704                 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  705                 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  706 
  707                 if (vp->v_type != VNON &&
  708                     vp->v_type != VBAD &&
  709                     VI_TRYLOCK(vp)) {
  710                         if (VMIGHTFREE(vp) &&           /* critical path opt */
  711                             (vp->v_object == NULL ||
  712                             vp->v_object->resident_page_count < trigger)) {
  713                                 mtx_unlock(&mntvnode_mtx);
  714                                 vgonel(vp, curthread);
  715                                 done++;
  716                                 mtx_lock(&mntvnode_mtx);
  717                         } else
  718                                 VI_UNLOCK(vp);
  719                 }
  720                 --count;
  721         }
  722         mtx_unlock(&mntvnode_mtx);
  723         return done;
  724 }
  725 
  726 /*
  727  * Attempt to recycle vnodes in a context that is always safe to block.
  728  * Calling vlrurecycle() from the bowels of filesystem code has some
  729  * interesting deadlock problems.
  730  */
  731 static struct proc *vnlruproc;
  732 static int vnlruproc_sig;
  733 
  734 static void
  735 vnlru_proc(void)
  736 {
  737         struct mount *mp, *nmp;
  738         int s;
  739         int done, take;
  740         struct proc *p = vnlruproc;
  741         struct thread *td = FIRST_THREAD_IN_PROC(p);    /* XXXKSE */
  742 
  743         mtx_lock(&Giant);
  744 
  745         EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
  746             SHUTDOWN_PRI_FIRST);
  747 
  748         s = splbio();
  749         for (;;) {
  750                 kthread_suspend_check(p);
  751                 mtx_lock(&vnode_free_list_mtx);
  752                 if (numvnodes - freevnodes <= desiredvnodes * 9 / 10) {
  753                         mtx_unlock(&vnode_free_list_mtx);
  754                         vnlruproc_sig = 0;
  755                         wakeup(&vnlruproc_sig);
  756                         tsleep(vnlruproc, PVFS, "vlruwt", hz);
  757                         continue;
  758                 }
  759                 mtx_unlock(&vnode_free_list_mtx);
  760                 done = 0;
  761                 mtx_lock(&mountlist_mtx);
  762                 take = 0;
  763                 TAILQ_FOREACH(mp, &mountlist, mnt_list)
  764                         take++;
  765                 take = desiredvnodes / (take * 10);
  766                 for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
  767                         if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
  768                                 nmp = TAILQ_NEXT(mp, mnt_list);
  769                                 continue;
  770                         }
  771                         done += vlrureclaim(mp, take);
  772                         mtx_lock(&mountlist_mtx);
  773                         nmp = TAILQ_NEXT(mp, mnt_list);
  774                         vfs_unbusy(mp, td);
  775                 }
  776                 mtx_unlock(&mountlist_mtx);
  777                 if (done == 0) {
  778 #if 0
  779                         /* These messages are temporary debugging aids */
  780                         if (vnlru_nowhere < 5)
  781                                 printf("vnlru process getting nowhere..\n");
  782                         else if (vnlru_nowhere == 5)
  783                                 printf("vnlru process messages stopped.\n");
  784 #endif
  785                         vnlru_nowhere++;
  786                         tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
  787                 }
  788         }
  789         splx(s);
  790 }
  791 
  792 static struct kproc_desc vnlru_kp = {
  793         "vnlru",
  794         vnlru_proc,
  795         &vnlruproc
  796 };
  797 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp)
  798 
  799 
  800 /*
  801  * Routines having to do with the management of the vnode table.
  802  */
  803 
  804 /*
  805  * Check to see if a free vnode can be recycled. If it can,
  806  * return it locked with the vn lock, but not interlock. Also
  807  * get the vn_start_write lock. Otherwise indicate the error.
  808  */
  809 static int
  810 vcanrecycle(struct vnode *vp, struct mount **vnmpp)
  811 {
  812         struct thread *td = curthread;
  813         vm_object_t object;
  814         int error;
  815 
  816         /* Don't recycle if we can't get the interlock */
  817         if (!VI_TRYLOCK(vp))
  818                 return (EWOULDBLOCK);
  819 
  820         /* We should be able to immediately acquire this */
  821         /* XXX This looks like it should panic if it fails */
  822         if (vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE, td) != 0) {
  823                 if (VOP_ISLOCKED(vp, td))
  824                         panic("vcanrecycle: locked vnode");
  825                 return (EWOULDBLOCK);
  826         }
  827 
  828         /*
  829          * Don't recycle if its filesystem is being suspended.
  830          */
  831         if (vn_start_write(vp, vnmpp, V_NOWAIT) != 0) {
  832                 error = EBUSY;
  833                 goto done;
  834         }
  835 
  836         /*
  837          * Don't recycle if we still have cached pages.
  838          */
  839         if (VOP_GETVOBJECT(vp, &object) == 0 &&
  840              (object->resident_page_count ||
  841               object->ref_count)) {
  842                 error = EBUSY;
  843                 goto done;
  844         }
  845         if (LIST_FIRST(&vp->v_cache_src)) {
  846                 /*
  847                  * note: nameileafonly sysctl is temporary,
  848                  * for debugging only, and will eventually be
  849                  * removed.
  850                  */
  851                 if (nameileafonly > 0) {
  852                         /*
  853                          * Do not reuse namei-cached directory
  854                          * vnodes that have cached
  855                          * subdirectories.
  856                          */
  857                         if (cache_leaf_test(vp) < 0) {
  858                                 error = EISDIR;
  859                                 goto done;
  860                         }
  861                 } else if (nameileafonly < 0 ||
  862                             vmiodirenable == 0) {
  863                         /*
  864                          * Do not reuse namei-cached directory
  865                          * vnodes if nameileafonly is -1 or
  866                          * if VMIO backing for directories is
  867                          * turned off (otherwise we reuse them
  868                          * too quickly).
  869                          */
  870                         error = EBUSY;
  871                         goto done;
  872                 }
  873         }
  874         return (0);
  875 done:
  876         VOP_UNLOCK(vp, 0, td);
  877         return (error);
  878 }
  879 
  880 /*
  881  * Return the next vnode from the free list.
  882  */
  883 int
  884 getnewvnode(tag, mp, vops, vpp)
  885         const char *tag;
  886         struct mount *mp;
  887         vop_t **vops;
  888         struct vnode **vpp;
  889 {
  890         int s;
  891         struct thread *td = curthread;  /* XXX */
  892         struct vnode *vp = NULL;
  893         struct vpollinfo *pollinfo = NULL;
  894         struct mount *vnmp;
  895 
  896         s = splbio();
  897         mtx_lock(&vnode_free_list_mtx);
  898 
  899         /*
  900          * Try to reuse vnodes if we hit the max.  This situation only
  901          * occurs in certain large-memory (2G+) situations.  We cannot
  902          * attempt to directly reclaim vnodes due to nasty recursion
  903          * problems.
  904          */
  905         while (numvnodes - freevnodes > desiredvnodes) {
  906                 if (vnlruproc_sig == 0) {
  907                         vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
  908                         wakeup(vnlruproc);
  909                 }
  910                 mtx_unlock(&vnode_free_list_mtx);
  911                 tsleep(&vnlruproc_sig, PVFS, "vlruwk", hz);
  912                 mtx_lock(&vnode_free_list_mtx);
  913         }
  914 
  915         /*
  916          * Attempt to reuse a vnode already on the free list, allocating
  917          * a new vnode if we can't find one or if we have not reached a
  918          * good minimum for good LRU performance.
  919          */
  920 
  921         if (freevnodes >= wantfreevnodes && numvnodes >= minvnodes) {
  922                 int error;
  923                 int count;
  924 
  925                 for (count = 0; count < freevnodes; count++) {
  926                         vp = TAILQ_FIRST(&vnode_free_list);
  927 
  928                         KASSERT(vp->v_usecount == 0, 
  929                             ("getnewvnode: free vnode isn't"));
  930 
  931                         TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
  932                         /*
  933                          * We have to drop the free list mtx to avoid lock
  934                          * order reversals with interlock.
  935                          */
  936                         mtx_unlock(&vnode_free_list_mtx);
  937                         error = vcanrecycle(vp, &vnmp);
  938                         mtx_lock(&vnode_free_list_mtx);
  939                         if (error == 0)
  940                                 break;
  941                         TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
  942                         vp = NULL;
  943                 }
  944         }
  945         if (vp) {
  946                 freevnodes--;
  947                 mtx_unlock(&vnode_free_list_mtx);
  948 
  949                 cache_purge(vp);
  950                 VI_LOCK(vp);
  951                 vp->v_iflag |= VI_DOOMED;
  952                 vp->v_iflag &= ~VI_FREE;
  953                 if (vp->v_type != VBAD) {
  954                         VOP_UNLOCK(vp, 0, td);
  955                         vgonel(vp, td);
  956                         VI_LOCK(vp);
  957                 } else {
  958                         VOP_UNLOCK(vp, 0, td);
  959                 }
  960                 vn_finished_write(vnmp);
  961 
  962 #ifdef INVARIANTS
  963                 {
  964                         if (vp->v_data)
  965                                 panic("cleaned vnode isn't");
  966                         if (vp->v_numoutput)
  967                                 panic("Clean vnode has pending I/O's");
  968                         if (vp->v_writecount != 0)
  969                                 panic("Non-zero write count");
  970                 }
  971 #endif
  972                 if ((pollinfo = vp->v_pollinfo) != NULL) {
  973                         /*
  974                          * To avoid lock order reversals, the call to
  975                          * uma_zfree() must be delayed until the vnode
  976                          * interlock is released.   
  977                          */
  978                         vp->v_pollinfo = NULL;
  979                 }
  980 #ifdef MAC
  981                 mac_destroy_vnode(vp);
  982 #endif
  983                 vp->v_iflag = 0;
  984                 vp->v_vflag = 0;
  985                 vp->v_lastw = 0;
  986                 vp->v_lasta = 0;
  987                 vp->v_cstart = 0;
  988                 vp->v_clen = 0;
  989                 vp->v_socket = 0;
  990                 lockdestroy(vp->v_vnlock);
  991                 lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOPAUSE);
  992                 KASSERT(vp->v_cleanblkroot == NULL, ("cleanblkroot not NULL"));
  993                 KASSERT(vp->v_dirtyblkroot == NULL, ("dirtyblkroot not NULL"));
  994         } else {
  995                 numvnodes++;
  996                 mtx_unlock(&vnode_free_list_mtx);
  997 
  998                 vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
  999                 mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
 1000                 VI_LOCK(vp);
 1001                 vp->v_dd = vp;
 1002                 vp->v_vnlock = &vp->v_lock;
 1003                 lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOPAUSE);
 1004                 cache_purge(vp);
 1005                 LIST_INIT(&vp->v_cache_src);
 1006                 TAILQ_INIT(&vp->v_cache_dst);
 1007         }
 1008 
 1009         TAILQ_INIT(&vp->v_cleanblkhd);
 1010         TAILQ_INIT(&vp->v_dirtyblkhd);
 1011         vp->v_type = VNON;
 1012         vp->v_tag = tag;
 1013         vp->v_op = vops;
 1014         *vpp = vp;
 1015         vp->v_usecount = 1;
 1016         vp->v_data = 0;
 1017         vp->v_cachedid = -1;
 1018         VI_UNLOCK(vp);
 1019         if (pollinfo != NULL) {
 1020                 mtx_destroy(&pollinfo->vpi_lock);
 1021                 uma_zfree(vnodepoll_zone, pollinfo);
 1022         }
 1023 #ifdef MAC
 1024         mac_init_vnode(vp);
 1025         if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
 1026                 mac_associate_vnode_singlelabel(mp, vp);
 1027 #endif
 1028         insmntque(vp, mp);
 1029 
 1030         return (0);
 1031 }
 1032 
 1033 /*
 1034  * Move a vnode from one mount queue to another.
 1035  */
 1036 static void
 1037 insmntque(vp, mp)
 1038         register struct vnode *vp;
 1039         register struct mount *mp;
 1040 {
 1041 
 1042         mtx_lock(&mntvnode_mtx);
 1043         /*
 1044          * Delete from old mount point vnode list, if on one.
 1045          */
 1046         if (vp->v_mount != NULL)
 1047                 TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
 1048         /*
 1049          * Insert into list of vnodes for the new mount point, if available.
 1050          */
 1051         if ((vp->v_mount = mp) == NULL) {
 1052                 mtx_unlock(&mntvnode_mtx);
 1053                 return;
 1054         }
 1055         TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1056         mtx_unlock(&mntvnode_mtx);
 1057 }
 1058 
 1059 /*
 1060  * Update outstanding I/O count and do wakeup if requested.
 1061  */
 1062 void
 1063 vwakeup(bp)
 1064         register struct buf *bp;
 1065 {
 1066         register struct vnode *vp;
 1067 
 1068         bp->b_flags &= ~B_WRITEINPROG;
 1069         if ((vp = bp->b_vp)) {
 1070                 VI_LOCK(vp);
 1071                 vp->v_numoutput--;
 1072                 if (vp->v_numoutput < 0)
 1073                         panic("vwakeup: neg numoutput");
 1074                 if ((vp->v_numoutput == 0) && (vp->v_iflag & VI_BWAIT)) {
 1075                         vp->v_iflag &= ~VI_BWAIT;
 1076                         wakeup(&vp->v_numoutput);
 1077                 }
 1078                 VI_UNLOCK(vp);
 1079         }
 1080 }
 1081 
 1082 /*
 1083  * Flush out and invalidate all buffers associated with a vnode.
 1084  * Called with the underlying object locked.
 1085  */
 1086 int
 1087 vinvalbuf(vp, flags, cred, td, slpflag, slptimeo)
 1088         struct vnode *vp;
 1089         int flags;
 1090         struct ucred *cred;
 1091         struct thread *td;
 1092         int slpflag, slptimeo;
 1093 {
 1094         struct buf *blist;
 1095         int s, error;
 1096         vm_object_t object;
 1097 
 1098         GIANT_REQUIRED;
 1099 
 1100         ASSERT_VOP_LOCKED(vp, "vinvalbuf");
 1101 
 1102         VI_LOCK(vp);
 1103         if (flags & V_SAVE) {
 1104                 s = splbio();
 1105                 while (vp->v_numoutput) {
 1106                         vp->v_iflag |= VI_BWAIT;
 1107                         error = msleep(&vp->v_numoutput, VI_MTX(vp),
 1108                             slpflag | (PRIBIO + 1), "vinvlbuf", slptimeo);
 1109                         if (error) {
 1110                                 VI_UNLOCK(vp);
 1111                                 splx(s);
 1112                                 return (error);
 1113                         }
 1114                 }
 1115                 if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
 1116                         splx(s);
 1117                         VI_UNLOCK(vp);
 1118                         if ((error = VOP_FSYNC(vp, cred, MNT_WAIT, td)) != 0)
 1119                                 return (error);
 1120                         /*
 1121                          * XXX We could save a lock/unlock if this was only
 1122                          * enabled under INVARIANTS
 1123                          */
 1124                         VI_LOCK(vp);
 1125                         s = splbio();
 1126                         if (vp->v_numoutput > 0 ||
 1127                             !TAILQ_EMPTY(&vp->v_dirtyblkhd))
 1128                                 panic("vinvalbuf: dirty bufs");
 1129                 }
 1130                 splx(s);
 1131         }
 1132         s = splbio();
 1133         /*
 1134          * If you alter this loop please notice that interlock is dropped and
 1135          * reacquired in flushbuflist.  Special care is needed to ensure that
 1136          * no race conditions occur from this.
 1137          */
 1138         for (error = 0;;) {
 1139                 if ((blist = TAILQ_FIRST(&vp->v_cleanblkhd)) != 0 &&
 1140                     flushbuflist(blist, flags, vp, slpflag, slptimeo, &error)) {
 1141                         if (error)
 1142                                 break;
 1143                         continue;
 1144                 }
 1145                 if ((blist = TAILQ_FIRST(&vp->v_dirtyblkhd)) != 0 &&
 1146                     flushbuflist(blist, flags, vp, slpflag, slptimeo, &error)) {
 1147                         if (error)
 1148                                 break;
 1149                         continue;
 1150                 }
 1151                 break;
 1152         }
 1153         if (error) {
 1154                 splx(s);
 1155                 VI_UNLOCK(vp);
 1156                 return (error);
 1157         }
 1158 
 1159         /*
 1160          * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
 1161          * have write I/O in-progress but if there is a VM object then the
 1162          * VM object can also have read-I/O in-progress.
 1163          */
 1164         do {
 1165                 while (vp->v_numoutput > 0) {
 1166                         vp->v_iflag |= VI_BWAIT;
 1167                         msleep(&vp->v_numoutput, VI_MTX(vp), PVM, "vnvlbv", 0);
 1168                 }
 1169                 VI_UNLOCK(vp);
 1170                 if (VOP_GETVOBJECT(vp, &object) == 0) {
 1171                         while (object->paging_in_progress)
 1172                         vm_object_pip_sleep(object, "vnvlbx");
 1173                 }
 1174                 VI_LOCK(vp);
 1175         } while (vp->v_numoutput > 0);
 1176         VI_UNLOCK(vp);
 1177 
 1178         splx(s);
 1179 
 1180         /*
 1181          * Destroy the copy in the VM cache, too.
 1182          */
 1183         if (VOP_GETVOBJECT(vp, &object) == 0) {
 1184                 vm_object_page_remove(object, 0, 0,
 1185                         (flags & V_SAVE) ? TRUE : FALSE);
 1186         }
 1187 
 1188 #ifdef INVARIANTS
 1189         VI_LOCK(vp);
 1190         if ((flags & (V_ALT | V_NORMAL)) == 0 &&
 1191             (!TAILQ_EMPTY(&vp->v_dirtyblkhd) ||
 1192              !TAILQ_EMPTY(&vp->v_cleanblkhd)))
 1193                 panic("vinvalbuf: flush failed");
 1194         VI_UNLOCK(vp);
 1195 #endif
 1196         return (0);
 1197 }
 1198 
 1199 /*
 1200  * Flush out buffers on the specified list.
 1201  *
 1202  */
 1203 static int
 1204 flushbuflist(blist, flags, vp, slpflag, slptimeo, errorp)
 1205         struct buf *blist;
 1206         int flags;
 1207         struct vnode *vp;
 1208         int slpflag, slptimeo;
 1209         int *errorp;
 1210 {
 1211         struct buf *bp, *nbp;
 1212         int found, error;
 1213 
 1214         ASSERT_VI_LOCKED(vp, "flushbuflist");
 1215 
 1216         for (found = 0, bp = blist; bp; bp = nbp) {
 1217                 nbp = TAILQ_NEXT(bp, b_vnbufs);
 1218                 VI_UNLOCK(vp);
 1219                 if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
 1220                     ((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
 1221                         VI_LOCK(vp);
 1222                         continue;
 1223                 }
 1224                 found += 1;
 1225                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
 1226                         error = BUF_TIMELOCK(bp,
 1227                             LK_EXCLUSIVE | LK_SLEEPFAIL,
 1228                             "flushbuf", slpflag, slptimeo);
 1229                         if (error != ENOLCK)
 1230                                 *errorp = error;
 1231                         goto done;
 1232                 }
 1233                 /*
 1234                  * XXX Since there are no node locks for NFS, I
 1235                  * believe there is a slight chance that a delayed
 1236                  * write will occur while sleeping just above, so
 1237                  * check for it.  Note that vfs_bio_awrite expects
 1238                  * buffers to reside on a queue, while BUF_WRITE and
 1239                  * brelse do not.
 1240                  */
 1241                 if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
 1242                         (flags & V_SAVE)) {
 1243 
 1244                         if (bp->b_vp == vp) {
 1245                                 if (bp->b_flags & B_CLUSTEROK) {
 1246                                         BUF_UNLOCK(bp);
 1247                                         vfs_bio_awrite(bp);
 1248                                 } else {
 1249                                         bremfree(bp);
 1250                                         bp->b_flags |= B_ASYNC;
 1251                                         BUF_WRITE(bp);
 1252                                 }
 1253                         } else {
 1254                                 bremfree(bp);
 1255                                 (void) BUF_WRITE(bp);
 1256                         }
 1257                         goto done;
 1258                 }
 1259                 bremfree(bp);
 1260                 bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
 1261                 bp->b_flags &= ~B_ASYNC;
 1262                 brelse(bp);
 1263                 VI_LOCK(vp);
 1264         }
 1265         return (found);
 1266 done:
 1267         VI_LOCK(vp);
 1268         return (found);
 1269 }
 1270 
 1271 /*
 1272  * Truncate a file's buffer and pages to a specified length.  This
 1273  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
 1274  * sync activity.
 1275  */
 1276 int
 1277 vtruncbuf(vp, cred, td, length, blksize)
 1278         register struct vnode *vp;
 1279         struct ucred *cred;
 1280         struct thread *td;
 1281         off_t length;
 1282         int blksize;
 1283 {
 1284         register struct buf *bp;
 1285         struct buf *nbp;
 1286         int s, anyfreed;
 1287         int trunclbn;
 1288 
 1289         /*
 1290          * Round up to the *next* lbn.
 1291          */
 1292         trunclbn = (length + blksize - 1) / blksize;
 1293 
 1294         s = splbio();
 1295         ASSERT_VOP_LOCKED(vp, "vtruncbuf");
 1296 restart:
 1297         VI_LOCK(vp);
 1298         anyfreed = 1;
 1299         for (;anyfreed;) {
 1300                 anyfreed = 0;
 1301                 for (bp = TAILQ_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
 1302                         nbp = TAILQ_NEXT(bp, b_vnbufs);
 1303                         VI_UNLOCK(vp);
 1304                         if (bp->b_lblkno >= trunclbn) {
 1305                                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
 1306                                         BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
 1307                                         goto restart;
 1308                                 } else {
 1309                                         bremfree(bp);
 1310                                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1311                                         bp->b_flags &= ~B_ASYNC;
 1312                                         brelse(bp);
 1313                                         anyfreed = 1;
 1314                                 }
 1315                                 if (nbp &&
 1316                                     (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
 1317                                     (nbp->b_vp != vp) ||
 1318                                     (nbp->b_flags & B_DELWRI))) {
 1319                                         goto restart;
 1320                                 }
 1321                         }
 1322                         VI_LOCK(vp);
 1323                 }
 1324 
 1325                 for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
 1326                         nbp = TAILQ_NEXT(bp, b_vnbufs);
 1327                         VI_UNLOCK(vp);
 1328                         if (bp->b_lblkno >= trunclbn) {
 1329                                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
 1330                                         BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
 1331                                         goto restart;
 1332                                 } else {
 1333                                         bremfree(bp);
 1334                                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1335                                         bp->b_flags &= ~B_ASYNC;
 1336                                         brelse(bp);
 1337                                         anyfreed = 1;
 1338                                 }
 1339                                 if (nbp &&
 1340                                     (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
 1341                                     (nbp->b_vp != vp) ||
 1342                                     (nbp->b_flags & B_DELWRI) == 0)) {
 1343                                         goto restart;
 1344                                 }
 1345                         }
 1346                         VI_LOCK(vp);
 1347                 }
 1348         }
 1349 
 1350         if (length > 0) {
 1351 restartsync:
 1352                 for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
 1353                         nbp = TAILQ_NEXT(bp, b_vnbufs);
 1354                         VI_UNLOCK(vp);
 1355                         if ((bp->b_flags & B_DELWRI) && (bp->b_lblkno < 0)) {
 1356                                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
 1357                                         BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
 1358                                         goto restart;
 1359                                 } else {
 1360                                         bremfree(bp);
 1361                                         if (bp->b_vp == vp) {
 1362                                                 bp->b_flags |= B_ASYNC;
 1363                                         } else {
 1364                                                 bp->b_flags &= ~B_ASYNC;
 1365                                         }
 1366                                         BUF_WRITE(bp);
 1367                                 }
 1368                                 VI_LOCK(vp);
 1369                                 goto restartsync;
 1370                         }
 1371                         VI_LOCK(vp);
 1372                 }
 1373         }
 1374         
 1375         while (vp->v_numoutput > 0) {
 1376                 vp->v_iflag |= VI_BWAIT;
 1377                 msleep(&vp->v_numoutput, VI_MTX(vp), PVM, "vbtrunc", 0);
 1378         }
 1379         VI_UNLOCK(vp);
 1380         splx(s);
 1381 
 1382         vnode_pager_setsize(vp, length);
 1383 
 1384         return (0);
 1385 }
 1386 
 1387 /*
 1388  * buf_splay() - splay tree core for the clean/dirty list of buffers in
 1389  *               a vnode.
 1390  *
 1391  *      NOTE: We have to deal with the special case of a background bitmap
 1392  *      buffer, a situation where two buffers will have the same logical
 1393  *      block offset.  We want (1) only the foreground buffer to be accessed
 1394  *      in a lookup and (2) must differentiate between the foreground and
 1395  *      background buffer in the splay tree algorithm because the splay
 1396  *      tree cannot normally handle multiple entities with the same 'index'.
 1397  *      We accomplish this by adding differentiating flags to the splay tree's
 1398  *      numerical domain.
 1399  */
 1400 static
 1401 struct buf *
 1402 buf_splay(daddr_t lblkno, b_xflags_t xflags, struct buf *root)
 1403 {
 1404         struct buf dummy;
 1405         struct buf *lefttreemax, *righttreemin, *y;
 1406 
 1407         if (root == NULL)
 1408                 return (NULL);
 1409         lefttreemax = righttreemin = &dummy;
 1410         for (;;) {
 1411                 if (lblkno < root->b_lblkno ||
 1412                     (lblkno == root->b_lblkno &&
 1413                     (xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1414                         if ((y = root->b_left) == NULL)
 1415                                 break;
 1416                         if (lblkno < y->b_lblkno) {
 1417                                 /* Rotate right. */
 1418                                 root->b_left = y->b_right;
 1419                                 y->b_right = root;
 1420                                 root = y;
 1421                                 if ((y = root->b_left) == NULL)
 1422                                         break;
 1423                         }
 1424                         /* Link into the new root's right tree. */
 1425                         righttreemin->b_left = root;
 1426                         righttreemin = root;
 1427                 } else if (lblkno > root->b_lblkno ||
 1428                     (lblkno == root->b_lblkno &&
 1429                     (xflags & BX_BKGRDMARKER) > (root->b_xflags & BX_BKGRDMARKER))) {
 1430                         if ((y = root->b_right) == NULL)
 1431                                 break;
 1432                         if (lblkno > y->b_lblkno) {
 1433                                 /* Rotate left. */
 1434                                 root->b_right = y->b_left;
 1435                                 y->b_left = root;
 1436                                 root = y;
 1437                                 if ((y = root->b_right) == NULL)
 1438                                         break;
 1439                         }
 1440                         /* Link into the new root's left tree. */
 1441                         lefttreemax->b_right = root;
 1442                         lefttreemax = root;
 1443                 } else {
 1444                         break;
 1445                 }
 1446                 root = y;
 1447         }
 1448         /* Assemble the new root. */
 1449         lefttreemax->b_right = root->b_left;
 1450         righttreemin->b_left = root->b_right;
 1451         root->b_left = dummy.b_right;
 1452         root->b_right = dummy.b_left;
 1453         return (root);
 1454 }
 1455 
 1456 static
 1457 void
 1458 buf_vlist_remove(struct buf *bp)
 1459 {
 1460         struct vnode *vp = bp->b_vp;
 1461         struct buf *root;
 1462 
 1463         ASSERT_VI_LOCKED(vp, "buf_vlist_remove");
 1464         if (bp->b_xflags & BX_VNDIRTY) {
 1465                 if (bp != vp->v_dirtyblkroot) {
 1466                         root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_dirtyblkroot);
 1467                         KASSERT(root == bp, ("splay lookup failed during dirty remove"));
 1468                 }
 1469                 if (bp->b_left == NULL) {
 1470                         root = bp->b_right;
 1471                 } else {
 1472                         root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
 1473                         root->b_right = bp->b_right;
 1474                 }
 1475                 vp->v_dirtyblkroot = root;
 1476                 TAILQ_REMOVE(&vp->v_dirtyblkhd, bp, b_vnbufs);
 1477         } else {
 1478                 /* KASSERT(bp->b_xflags & BX_VNCLEAN, ("bp wasn't clean")); */
 1479                 if (bp != vp->v_cleanblkroot) {
 1480                         root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_cleanblkroot);
 1481                         KASSERT(root == bp, ("splay lookup failed during clean remove"));
 1482                 }
 1483                 if (bp->b_left == NULL) {
 1484                         root = bp->b_right;
 1485                 } else {
 1486                         root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
 1487                         root->b_right = bp->b_right;
 1488                 }
 1489                 vp->v_cleanblkroot = root;
 1490                 TAILQ_REMOVE(&vp->v_cleanblkhd, bp, b_vnbufs);
 1491         }
 1492         bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
 1493 }
 1494 
 1495 /*
 1496  * Add the buffer to the sorted clean or dirty block list using a
 1497  * splay tree algorithm.
 1498  *
 1499  * NOTE: xflags is passed as a constant, optimizing this inline function!
 1500  */
 1501 static 
 1502 void
 1503 buf_vlist_add(struct buf *bp, struct vnode *vp, b_xflags_t xflags)
 1504 {
 1505         struct buf *root;
 1506 
 1507         ASSERT_VI_LOCKED(vp, "buf_vlist_add");
 1508         bp->b_xflags |= xflags;
 1509         if (xflags & BX_VNDIRTY) {
 1510                 root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_dirtyblkroot);
 1511                 if (root == NULL) {
 1512                         bp->b_left = NULL;
 1513                         bp->b_right = NULL;
 1514                         TAILQ_INSERT_TAIL(&vp->v_dirtyblkhd, bp, b_vnbufs);
 1515                 } else if (bp->b_lblkno < root->b_lblkno ||
 1516                     (bp->b_lblkno == root->b_lblkno &&
 1517                     (bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1518                         bp->b_left = root->b_left;
 1519                         bp->b_right = root;
 1520                         root->b_left = NULL;
 1521                         TAILQ_INSERT_BEFORE(root, bp, b_vnbufs);
 1522                 } else {
 1523                         bp->b_right = root->b_right;
 1524                         bp->b_left = root;
 1525                         root->b_right = NULL;
 1526                         TAILQ_INSERT_AFTER(&vp->v_dirtyblkhd, 
 1527                             root, bp, b_vnbufs);
 1528                 }
 1529                 vp->v_dirtyblkroot = bp;
 1530         } else {
 1531                 /* KASSERT(xflags & BX_VNCLEAN, ("xflags not clean")); */
 1532                 root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_cleanblkroot);
 1533                 if (root == NULL) {
 1534                         bp->b_left = NULL;
 1535                         bp->b_right = NULL;
 1536                         TAILQ_INSERT_TAIL(&vp->v_cleanblkhd, bp, b_vnbufs);
 1537                 } else if (bp->b_lblkno < root->b_lblkno ||
 1538                     (bp->b_lblkno == root->b_lblkno &&
 1539                     (bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1540                         bp->b_left = root->b_left;
 1541                         bp->b_right = root;
 1542                         root->b_left = NULL;
 1543                         TAILQ_INSERT_BEFORE(root, bp, b_vnbufs);
 1544                 } else {
 1545                         bp->b_right = root->b_right;
 1546                         bp->b_left = root;
 1547                         root->b_right = NULL;
 1548                         TAILQ_INSERT_AFTER(&vp->v_cleanblkhd, 
 1549                             root, bp, b_vnbufs);
 1550                 }
 1551                 vp->v_cleanblkroot = bp;
 1552         }
 1553 }
 1554 
 1555 #ifndef USE_BUFHASH
 1556 
 1557 /*
 1558  * Lookup a buffer using the splay tree.  Note that we specifically avoid
 1559  * shadow buffers used in background bitmap writes.
 1560  *
 1561  * This code isn't quite efficient as it could be because we are maintaining
 1562  * two sorted lists and do not know which list the block resides in.
 1563  */
 1564 struct buf *
 1565 gbincore(struct vnode *vp, daddr_t lblkno)
 1566 {
 1567         struct buf *bp;
 1568 
 1569         GIANT_REQUIRED;
 1570 
 1571         ASSERT_VI_LOCKED(vp, "gbincore");
 1572         bp = vp->v_cleanblkroot = buf_splay(lblkno, 0, vp->v_cleanblkroot);
 1573         if (bp && bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1574                 return(bp);
 1575         bp = vp->v_dirtyblkroot = buf_splay(lblkno, 0, vp->v_dirtyblkroot);
 1576         if (bp && bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1577                 return(bp);
 1578         return(NULL);
 1579 }
 1580 
 1581 #endif
 1582 
 1583 /*
 1584  * Associate a buffer with a vnode.
 1585  */
 1586 void
 1587 bgetvp(vp, bp)
 1588         register struct vnode *vp;
 1589         register struct buf *bp;
 1590 {
 1591         int s;
 1592 
 1593         KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
 1594 
 1595         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
 1596             ("bgetvp: bp already attached! %p", bp));
 1597 
 1598         VI_LOCK(vp);
 1599         vholdl(vp);
 1600         bp->b_vp = vp;
 1601         bp->b_dev = vn_todev(vp);
 1602         /*
 1603          * Insert onto list for new vnode.
 1604          */
 1605         s = splbio();
 1606         buf_vlist_add(bp, vp, BX_VNCLEAN);
 1607         splx(s);
 1608         VI_UNLOCK(vp);
 1609 }
 1610 
 1611 /*
 1612  * Disassociate a buffer from a vnode.
 1613  */
 1614 void
 1615 brelvp(bp)
 1616         register struct buf *bp;
 1617 {
 1618         struct vnode *vp;
 1619         int s;
 1620 
 1621         KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
 1622 
 1623         /*
 1624          * Delete from old vnode list, if on one.
 1625          */
 1626         vp = bp->b_vp;
 1627         s = splbio();
 1628         VI_LOCK(vp);
 1629         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1630                 buf_vlist_remove(bp);
 1631         if ((vp->v_iflag & VI_ONWORKLST) && TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
 1632                 vp->v_iflag &= ~VI_ONWORKLST;
 1633                 mtx_lock(&sync_mtx);
 1634                 LIST_REMOVE(vp, v_synclist);
 1635                 mtx_unlock(&sync_mtx);
 1636         }
 1637         vdropl(vp);
 1638         VI_UNLOCK(vp);
 1639         bp->b_vp = (struct vnode *) 0;
 1640         if (bp->b_object)
 1641                 bp->b_object = NULL;
 1642         splx(s);
 1643 }
 1644 
 1645 /*
 1646  * Add an item to the syncer work queue.
 1647  */
 1648 static void
 1649 vn_syncer_add_to_worklist(struct vnode *vp, int delay)
 1650 {
 1651         int s, slot;
 1652 
 1653         s = splbio();
 1654         ASSERT_VI_LOCKED(vp, "vn_syncer_add_to_worklist");
 1655 
 1656         mtx_lock(&sync_mtx);
 1657         if (vp->v_iflag & VI_ONWORKLST)
 1658                 LIST_REMOVE(vp, v_synclist);
 1659         else
 1660                 vp->v_iflag |= VI_ONWORKLST;
 1661 
 1662         if (delay > syncer_maxdelay - 2)
 1663                 delay = syncer_maxdelay - 2;
 1664         slot = (syncer_delayno + delay) & syncer_mask;
 1665 
 1666         LIST_INSERT_HEAD(&syncer_workitem_pending[slot], vp, v_synclist);
 1667         mtx_unlock(&sync_mtx);
 1668 
 1669         splx(s);
 1670 }
 1671 
 1672 struct  proc *updateproc;
 1673 static void sched_sync(void);
 1674 static struct kproc_desc up_kp = {
 1675         "syncer",
 1676         sched_sync,
 1677         &updateproc
 1678 };
 1679 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp)
 1680 
 1681 /*
 1682  * System filesystem synchronizer daemon.
 1683  */
 1684 static void
 1685 sched_sync(void)
 1686 {
 1687         struct synclist *slp;
 1688         struct vnode *vp;
 1689         struct mount *mp;
 1690         long starttime;
 1691         int s;
 1692         struct thread *td = FIRST_THREAD_IN_PROC(updateproc);  /* XXXKSE */
 1693 
 1694         mtx_lock(&Giant);
 1695 
 1696         EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, td->td_proc,
 1697             SHUTDOWN_PRI_LAST);
 1698 
 1699         for (;;) {
 1700                 kthread_suspend_check(td->td_proc);
 1701 
 1702                 starttime = time_second;
 1703 
 1704                 /*
 1705                  * Push files whose dirty time has expired.  Be careful
 1706                  * of interrupt race on slp queue.
 1707                  */
 1708                 s = splbio();
 1709                 mtx_lock(&sync_mtx);
 1710                 slp = &syncer_workitem_pending[syncer_delayno];
 1711                 syncer_delayno += 1;
 1712                 if (syncer_delayno == syncer_maxdelay)
 1713                         syncer_delayno = 0;
 1714                 splx(s);
 1715 
 1716                 while ((vp = LIST_FIRST(slp)) != NULL) {
 1717                         mtx_unlock(&sync_mtx);
 1718                         if (VOP_ISLOCKED(vp, NULL) == 0 &&
 1719                             vn_start_write(vp, &mp, V_NOWAIT) == 0) {
 1720                                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
 1721                                 (void) VOP_FSYNC(vp, td->td_ucred, MNT_LAZY, td);
 1722                                 VOP_UNLOCK(vp, 0, td);
 1723                                 vn_finished_write(mp);
 1724                         }
 1725                         s = splbio();
 1726                         mtx_lock(&sync_mtx);
 1727                         if (LIST_FIRST(slp) == vp) {
 1728                                 mtx_unlock(&sync_mtx);
 1729                                 /*
 1730                                  * Note: VFS vnodes can remain on the
 1731                                  * worklist too with no dirty blocks, but
 1732                                  * since sync_fsync() moves it to a different
 1733                                  * slot we are safe.
 1734                                  */
 1735                                 VI_LOCK(vp);
 1736                                 if (TAILQ_EMPTY(&vp->v_dirtyblkhd) &&
 1737                                     !vn_isdisk(vp, NULL)) {
 1738                                         panic("sched_sync: fsync failed "
 1739                                               "vp %p tag %s", vp, vp->v_tag);
 1740                                 }
 1741                                 /*
 1742                                  * Put us back on the worklist.  The worklist
 1743                                  * routine will remove us from our current
 1744                                  * position and then add us back in at a later
 1745                                  * position.
 1746                                  */
 1747                                 vn_syncer_add_to_worklist(vp, syncdelay);
 1748                                 VI_UNLOCK(vp);
 1749                                 mtx_lock(&sync_mtx);
 1750                         }
 1751                         splx(s);
 1752                 }
 1753                 mtx_unlock(&sync_mtx);
 1754 
 1755                 /*
 1756                  * Do soft update processing.
 1757                  */
 1758                 if (softdep_process_worklist_hook != NULL)
 1759                         (*softdep_process_worklist_hook)(NULL);
 1760 
 1761                 /*
 1762                  * The variable rushjob allows the kernel to speed up the
 1763                  * processing of the filesystem syncer process. A rushjob
 1764                  * value of N tells the filesystem syncer to process the next
 1765                  * N seconds worth of work on its queue ASAP. Currently rushjob
 1766                  * is used by the soft update code to speed up the filesystem
 1767                  * syncer process when the incore state is getting so far
 1768                  * ahead of the disk that the kernel memory pool is being
 1769                  * threatened with exhaustion.
 1770                  */
 1771                 mtx_lock(&sync_mtx);
 1772                 if (rushjob > 0) {
 1773                         rushjob -= 1;
 1774                         mtx_unlock(&sync_mtx);
 1775                         continue;
 1776                 }
 1777                 mtx_unlock(&sync_mtx);
 1778                 /*
 1779                  * If it has taken us less than a second to process the
 1780                  * current work, then wait. Otherwise start right over
 1781                  * again. We can still lose time if any single round
 1782                  * takes more than two seconds, but it does not really
 1783                  * matter as we are just trying to generally pace the
 1784                  * filesystem activity.
 1785                  */
 1786                 if (time_second == starttime)
 1787                         tsleep(&lbolt, PPAUSE, "syncer", 0);
 1788         }
 1789 }
 1790 
 1791 /*
 1792  * Request the syncer daemon to speed up its work.
 1793  * We never push it to speed up more than half of its
 1794  * normal turn time, otherwise it could take over the cpu.
 1795  * XXXKSE  only one update?
 1796  */
 1797 int
 1798 speedup_syncer()
 1799 {
 1800         struct thread *td;
 1801         int ret = 0;
 1802 
 1803         td = FIRST_THREAD_IN_PROC(updateproc);
 1804         mtx_lock_spin(&sched_lock);
 1805         if (td->td_wchan == &lbolt) {
 1806                 unsleep(td);
 1807                 TD_CLR_SLEEPING(td);
 1808                 setrunnable(td);
 1809         }
 1810         mtx_unlock_spin(&sched_lock);
 1811         mtx_lock(&sync_mtx);
 1812         if (rushjob < syncdelay / 2) {
 1813                 rushjob += 1;
 1814                 stat_rush_requests += 1;
 1815                 ret = 1;
 1816         }
 1817         mtx_unlock(&sync_mtx);
 1818         return (ret);
 1819 }
 1820 
 1821 /*
 1822  * Associate a p-buffer with a vnode.
 1823  *
 1824  * Also sets B_PAGING flag to indicate that vnode is not fully associated
 1825  * with the buffer.  i.e. the bp has not been linked into the vnode or
 1826  * ref-counted.
 1827  */
 1828 void
 1829 pbgetvp(vp, bp)
 1830         register struct vnode *vp;
 1831         register struct buf *bp;
 1832 {
 1833 
 1834         KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
 1835 
 1836         bp->b_vp = vp;
 1837         bp->b_flags |= B_PAGING;
 1838         bp->b_dev = vn_todev(vp);
 1839 }
 1840 
 1841 /*
 1842  * Disassociate a p-buffer from a vnode.
 1843  */
 1844 void
 1845 pbrelvp(bp)
 1846         register struct buf *bp;
 1847 {
 1848 
 1849         KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
 1850 
 1851         /* XXX REMOVE ME */
 1852         VI_LOCK(bp->b_vp);
 1853         if (TAILQ_NEXT(bp, b_vnbufs) != NULL) {
 1854                 panic(
 1855                     "relpbuf(): b_vp was probably reassignbuf()d %p %x",
 1856                     bp,
 1857                     (int)bp->b_flags
 1858                 );
 1859         }
 1860         VI_UNLOCK(bp->b_vp);
 1861         bp->b_vp = (struct vnode *) 0;
 1862         bp->b_flags &= ~B_PAGING;
 1863 }
 1864 
 1865 /*
 1866  * Reassign a buffer from one vnode to another.
 1867  * Used to assign file specific control information
 1868  * (indirect blocks) to the vnode to which they belong.
 1869  */
 1870 void
 1871 reassignbuf(bp, newvp)
 1872         register struct buf *bp;
 1873         register struct vnode *newvp;
 1874 {
 1875         int delay;
 1876         int s;
 1877 
 1878         if (newvp == NULL) {
 1879                 printf("reassignbuf: NULL");
 1880                 return;
 1881         }
 1882         ++reassignbufcalls;
 1883 
 1884         /*
 1885          * B_PAGING flagged buffers cannot be reassigned because their vp
 1886          * is not fully linked in.
 1887          */
 1888         if (bp->b_flags & B_PAGING)
 1889                 panic("cannot reassign paging buffer");
 1890 
 1891         s = splbio();
 1892         /*
 1893          * Delete from old vnode list, if on one.
 1894          */
 1895         VI_LOCK(bp->b_vp);
 1896         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
 1897                 buf_vlist_remove(bp);
 1898                 if (bp->b_vp != newvp) {
 1899                         vdropl(bp->b_vp);
 1900                         bp->b_vp = NULL;        /* for clarification */
 1901                 }
 1902         }
 1903         VI_UNLOCK(bp->b_vp);
 1904         /*
 1905          * If dirty, put on list of dirty buffers; otherwise insert onto list
 1906          * of clean buffers.
 1907          */
 1908         VI_LOCK(newvp);
 1909         if (bp->b_flags & B_DELWRI) {
 1910                 if ((newvp->v_iflag & VI_ONWORKLST) == 0) {
 1911                         switch (newvp->v_type) {
 1912                         case VDIR:
 1913                                 delay = dirdelay;
 1914                                 break;
 1915                         case VCHR:
 1916                                 if (newvp->v_rdev->si_mountpoint != NULL) {
 1917                                         delay = metadelay;
 1918                                         break;
 1919                                 }
 1920                                 /* FALLTHROUGH */
 1921                         default:
 1922                                 delay = filedelay;
 1923                         }
 1924                         vn_syncer_add_to_worklist(newvp, delay);
 1925                 }
 1926                 buf_vlist_add(bp, newvp, BX_VNDIRTY);
 1927         } else {
 1928                 buf_vlist_add(bp, newvp, BX_VNCLEAN);
 1929 
 1930                 if ((newvp->v_iflag & VI_ONWORKLST) &&
 1931                     TAILQ_EMPTY(&newvp->v_dirtyblkhd)) {
 1932                         mtx_lock(&sync_mtx);
 1933                         LIST_REMOVE(newvp, v_synclist);
 1934                         mtx_unlock(&sync_mtx);
 1935                         newvp->v_iflag &= ~VI_ONWORKLST;
 1936                 }
 1937         }
 1938         if (bp->b_vp != newvp) {
 1939                 bp->b_vp = newvp;
 1940                 vholdl(bp->b_vp);
 1941         }
 1942         VI_UNLOCK(newvp);
 1943         splx(s);
 1944 }
 1945 
 1946 /*
 1947  * Create a vnode for a device.
 1948  * Used for mounting the root filesystem.
 1949  */
 1950 int
 1951 bdevvp(dev, vpp)
 1952         dev_t dev;
 1953         struct vnode **vpp;
 1954 {
 1955         register struct vnode *vp;
 1956         struct vnode *nvp;
 1957         int error;
 1958 
 1959         if (dev == NODEV) {
 1960                 *vpp = NULLVP;
 1961                 return (ENXIO);
 1962         }
 1963         if (vfinddev(dev, VCHR, vpp))
 1964                 return (0);
 1965         error = getnewvnode("none", (struct mount *)0, spec_vnodeop_p, &nvp);
 1966         if (error) {
 1967                 *vpp = NULLVP;
 1968                 return (error);
 1969         }
 1970         vp = nvp;
 1971         vp->v_type = VCHR;
 1972         addalias(vp, dev);
 1973         *vpp = vp;
 1974         return (0);
 1975 }
 1976 
 1977 static void
 1978 v_incr_usecount(struct vnode *vp, int delta)
 1979 {
 1980         vp->v_usecount += delta;
 1981         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 1982                 mtx_lock(&spechash_mtx);
 1983                 vp->v_rdev->si_usecount += delta;
 1984                 mtx_unlock(&spechash_mtx);
 1985         }
 1986 }
 1987 
 1988 /*
 1989  * Add vnode to the alias list hung off the dev_t.
 1990  *
 1991  * The reason for this gunk is that multiple vnodes can reference
 1992  * the same physical device, so checking vp->v_usecount to see
 1993  * how many users there are is inadequate; the v_usecount for
 1994  * the vnodes need to be accumulated.  vcount() does that.
 1995  */
 1996 struct vnode *
 1997 addaliasu(nvp, nvp_rdev)
 1998         struct vnode *nvp;
 1999         udev_t nvp_rdev;
 2000 {
 2001         struct vnode *ovp;
 2002         vop_t **ops;
 2003         dev_t dev;
 2004 
 2005         if (nvp->v_type == VBLK)
 2006                 return (nvp);
 2007         if (nvp->v_type != VCHR)
 2008                 panic("addaliasu on non-special vnode");
 2009         dev = udev2dev(nvp_rdev, 0);
 2010         /*
 2011          * Check to see if we have a bdevvp vnode with no associated
 2012          * filesystem. If so, we want to associate the filesystem of
 2013          * the new newly instigated vnode with the bdevvp vnode and
 2014          * discard the newly created vnode rather than leaving the
 2015          * bdevvp vnode lying around with no associated filesystem.
 2016          */
 2017         if (vfinddev(dev, nvp->v_type, &ovp) == 0 || ovp->v_data != NULL) {
 2018                 addalias(nvp, dev);
 2019                 return (nvp);
 2020         }
 2021         /*
 2022          * Discard unneeded vnode, but save its node specific data.
 2023          * Note that if there is a lock, it is carried over in the
 2024          * node specific data to the replacement vnode.
 2025          */
 2026         vref(ovp);
 2027         ovp->v_data = nvp->v_data;
 2028         ovp->v_tag = nvp->v_tag;
 2029         nvp->v_data = NULL;
 2030         lockdestroy(ovp->v_vnlock);
 2031         lockinit(ovp->v_vnlock, PVFS, nvp->v_vnlock->lk_wmesg,
 2032             nvp->v_vnlock->lk_timo, nvp->v_vnlock->lk_flags & LK_EXTFLG_MASK);
 2033         ops = ovp->v_op;
 2034         ovp->v_op = nvp->v_op;
 2035         if (VOP_ISLOCKED(nvp, curthread)) {
 2036                 VOP_UNLOCK(nvp, 0, curthread);
 2037                 vn_lock(ovp, LK_EXCLUSIVE | LK_RETRY, curthread);
 2038         }
 2039         nvp->v_op = ops;
 2040         insmntque(ovp, nvp->v_mount);
 2041         vrele(nvp);
 2042         vgone(nvp);
 2043         return (ovp);
 2044 }
 2045 
 2046 /* This is a local helper function that do the same as addaliasu, but for a
 2047  * dev_t instead of an udev_t. */
 2048 static void
 2049 addalias(nvp, dev)
 2050         struct vnode *nvp;
 2051         dev_t dev;
 2052 {
 2053 
 2054         KASSERT(nvp->v_type == VCHR, ("addalias on non-special vnode"));
 2055         nvp->v_rdev = dev;
 2056         VI_LOCK(nvp);
 2057         mtx_lock(&spechash_mtx);
 2058         SLIST_INSERT_HEAD(&dev->si_hlist, nvp, v_specnext);
 2059         dev->si_usecount += nvp->v_usecount;
 2060         mtx_unlock(&spechash_mtx);
 2061         VI_UNLOCK(nvp);
 2062 }
 2063 
 2064 /*
 2065  * Grab a particular vnode from the free list, increment its
 2066  * reference count and lock it. The vnode lock bit is set if the
 2067  * vnode is being eliminated in vgone. The process is awakened
 2068  * when the transition is completed, and an error returned to
 2069  * indicate that the vnode is no longer usable (possibly having
 2070  * been changed to a new filesystem type).
 2071  */
 2072 int
 2073 vget(vp, flags, td)
 2074         register struct vnode *vp;
 2075         int flags;
 2076         struct thread *td;
 2077 {
 2078         int error;
 2079 
 2080         /*
 2081          * If the vnode is in the process of being cleaned out for
 2082          * another use, we wait for the cleaning to finish and then
 2083          * return failure. Cleaning is determined by checking that
 2084          * the VI_XLOCK flag is set.
 2085          */
 2086         if ((flags & LK_INTERLOCK) == 0)
 2087                 VI_LOCK(vp);
 2088         if (vp->v_iflag & VI_XLOCK && vp->v_vxproc != curthread) {
 2089                 vp->v_iflag |= VI_XWANT;
 2090                 msleep(vp, VI_MTX(vp), PINOD | PDROP, "vget", 0);
 2091                 return (ENOENT);
 2092         }
 2093 
 2094         v_incr_usecount(vp, 1);
 2095 
 2096         if (VSHOULDBUSY(vp))
 2097                 vbusy(vp);
 2098         if (flags & LK_TYPE_MASK) {
 2099                 if ((error = vn_lock(vp, flags | LK_INTERLOCK, td)) != 0) {
 2100                         /*
 2101                          * must expand vrele here because we do not want
 2102                          * to call VOP_INACTIVE if the reference count
 2103                          * drops back to zero since it was never really
 2104                          * active. We must remove it from the free list
 2105                          * before sleeping so that multiple processes do
 2106                          * not try to recycle it.
 2107                          */
 2108                         VI_LOCK(vp);
 2109                         v_incr_usecount(vp, -1);
 2110                         if (VSHOULDFREE(vp))
 2111                                 vfree(vp);
 2112                         else
 2113                                 vlruvp(vp);
 2114                         VI_UNLOCK(vp);
 2115                 }
 2116                 return (error);
 2117         }
 2118         VI_UNLOCK(vp);
 2119         return (0);
 2120 }
 2121 
 2122 /*
 2123  * Increase the reference count of a vnode.
 2124  */
 2125 void
 2126 vref(struct vnode *vp)
 2127 {
 2128         VI_LOCK(vp);
 2129         v_incr_usecount(vp, 1);
 2130         VI_UNLOCK(vp);
 2131 }
 2132 
 2133 /*
 2134  * Return reference count of a vnode.
 2135  *
 2136  * The results of this call are only guaranteed when some mechanism other
 2137  * than the VI lock is used to stop other processes from gaining references
 2138  * to the vnode.  This may be the case if the caller holds the only reference.
 2139  * This is also useful when stale data is acceptable as race conditions may
 2140  * be accounted for by some other means.
 2141  */
 2142 int
 2143 vrefcnt(struct vnode *vp)
 2144 {
 2145         int usecnt;
 2146 
 2147         VI_LOCK(vp);
 2148         usecnt = vp->v_usecount;
 2149         VI_UNLOCK(vp);
 2150 
 2151         return (usecnt);
 2152 }
 2153 
 2154 
 2155 /*
 2156  * Vnode put/release.
 2157  * If count drops to zero, call inactive routine and return to freelist.
 2158  */
 2159 void
 2160 vrele(vp)
 2161         struct vnode *vp;
 2162 {
 2163         struct thread *td = curthread;  /* XXX */
 2164 
 2165         KASSERT(vp != NULL, ("vrele: null vp"));
 2166 
 2167         VI_LOCK(vp);
 2168 
 2169         /* Skip this v_writecount check if we're going to panic below. */
 2170         KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
 2171             ("vrele: missed vn_close"));
 2172 
 2173         if (vp->v_usecount > 1) {
 2174 
 2175                 v_incr_usecount(vp, -1);
 2176                 VI_UNLOCK(vp);
 2177 
 2178                 return;
 2179         }
 2180 
 2181         if (vp->v_usecount == 1) {
 2182                 v_incr_usecount(vp, -1);
 2183                 /*
 2184                  * We must call VOP_INACTIVE with the node locked.
 2185                  * If we are doing a vput, the node is already locked,
 2186                  * but, in the case of vrele, we must explicitly lock
 2187                  * the vnode before calling VOP_INACTIVE.
 2188                  */
 2189                 if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK, td) == 0)
 2190                         VOP_INACTIVE(vp, td);
 2191                 VI_LOCK(vp);
 2192                 if (VSHOULDFREE(vp))
 2193                         vfree(vp);
 2194                 else
 2195                         vlruvp(vp);
 2196                 VI_UNLOCK(vp);
 2197 
 2198         } else {
 2199 #ifdef DIAGNOSTIC
 2200                 vprint("vrele: negative ref count", vp);
 2201 #endif
 2202                 VI_UNLOCK(vp);
 2203                 panic("vrele: negative ref cnt");
 2204         }
 2205 }
 2206 
 2207 /*
 2208  * Release an already locked vnode.  This give the same effects as
 2209  * unlock+vrele(), but takes less time and avoids releasing and
 2210  * re-aquiring the lock (as vrele() aquires the lock internally.)
 2211  */
 2212 void
 2213 vput(vp)
 2214         struct vnode *vp;
 2215 {
 2216         struct thread *td = curthread;  /* XXX */
 2217 
 2218         GIANT_REQUIRED;
 2219 
 2220         KASSERT(vp != NULL, ("vput: null vp"));
 2221         VI_LOCK(vp);
 2222         /* Skip this v_writecount check if we're going to panic below. */
 2223         KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
 2224             ("vput: missed vn_close"));
 2225 
 2226         if (vp->v_usecount > 1) {
 2227                 v_incr_usecount(vp, -1);
 2228                 VOP_UNLOCK(vp, LK_INTERLOCK, td);
 2229                 return;
 2230         }
 2231 
 2232         if (vp->v_usecount == 1) {
 2233                 v_incr_usecount(vp, -1);
 2234                 /*
 2235                  * We must call VOP_INACTIVE with the node locked.
 2236                  * If we are doing a vput, the node is already locked,
 2237                  * so we just need to release the vnode mutex.
 2238                  */
 2239                 VI_UNLOCK(vp);
 2240                 VOP_INACTIVE(vp, td);
 2241                 VI_LOCK(vp);
 2242                 if (VSHOULDFREE(vp))
 2243                         vfree(vp);
 2244                 else
 2245                         vlruvp(vp);
 2246                 VI_UNLOCK(vp);
 2247 
 2248         } else {
 2249 #ifdef DIAGNOSTIC
 2250                 vprint("vput: negative ref count", vp);
 2251 #endif
 2252                 panic("vput: negative ref cnt");
 2253         }
 2254 }
 2255 
 2256 /*
 2257  * Somebody doesn't want the vnode recycled.
 2258  */
 2259 void
 2260 vhold(struct vnode *vp)
 2261 {
 2262         VI_LOCK(vp);
 2263         vholdl(vp);
 2264         VI_UNLOCK(vp);
 2265 }
 2266 
 2267 void
 2268 vholdl(vp)
 2269         register struct vnode *vp;
 2270 {
 2271         int s;
 2272 
 2273         s = splbio();
 2274         vp->v_holdcnt++;
 2275         if (VSHOULDBUSY(vp))
 2276                 vbusy(vp);
 2277         splx(s);
 2278 }
 2279 
 2280 /*
 2281  * Note that there is one less who cares about this vnode.  vdrop() is the
 2282  * opposite of vhold().
 2283  */
 2284 void
 2285 vdrop(struct vnode *vp)
 2286 {
 2287         VI_LOCK(vp);
 2288         vdropl(vp);
 2289         VI_UNLOCK(vp);
 2290 }
 2291         
 2292 void
 2293 vdropl(vp)
 2294         register struct vnode *vp;
 2295 {
 2296         int s;
 2297 
 2298         s = splbio();
 2299         if (vp->v_holdcnt <= 0)
 2300                 panic("vdrop: holdcnt");
 2301         vp->v_holdcnt--;
 2302         if (VSHOULDFREE(vp))
 2303                 vfree(vp);
 2304         else
 2305                 vlruvp(vp);
 2306         splx(s);
 2307 }
 2308 
 2309 /*
 2310  * Remove any vnodes in the vnode table belonging to mount point mp.
 2311  *
 2312  * If FORCECLOSE is not specified, there should not be any active ones,
 2313  * return error if any are found (nb: this is a user error, not a
 2314  * system error). If FORCECLOSE is specified, detach any active vnodes
 2315  * that are found.
 2316  *
 2317  * If WRITECLOSE is set, only flush out regular file vnodes open for
 2318  * writing.
 2319  *
 2320  * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
 2321  *
 2322  * `rootrefs' specifies the base reference count for the root vnode
 2323  * of this filesystem. The root vnode is considered busy if its
 2324  * v_usecount exceeds this value. On a successful return, vflush()
 2325  * will call vrele() on the root vnode exactly rootrefs times.
 2326  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
 2327  * be zero.
 2328  */
 2329 #ifdef DIAGNOSTIC
 2330 static int busyprt = 0;         /* print out busy vnodes */
 2331 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "");
 2332 #endif
 2333 
 2334 int
 2335 vflush(mp, rootrefs, flags)
 2336         struct mount *mp;
 2337         int rootrefs;
 2338         int flags;
 2339 {
 2340         struct thread *td = curthread;  /* XXX */
 2341         struct vnode *vp, *nvp, *rootvp = NULL;
 2342         struct vattr vattr;
 2343         int busy = 0, error;
 2344 
 2345         if (rootrefs > 0) {
 2346                 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
 2347                     ("vflush: bad args"));
 2348                 /*
 2349                  * Get the filesystem root vnode. We can vput() it
 2350                  * immediately, since with rootrefs > 0, it won't go away.
 2351                  */
 2352                 if ((error = VFS_ROOT(mp, &rootvp)) != 0)
 2353                         return (error);
 2354                 vput(rootvp);
 2355 
 2356         }
 2357         mtx_lock(&mntvnode_mtx);
 2358 loop:
 2359         for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp; vp = nvp) {
 2360                 /*
 2361                  * Make sure this vnode wasn't reclaimed in getnewvnode().
 2362                  * Start over if it has (it won't be on the list anymore).
 2363                  */
 2364                 if (vp->v_mount != mp)
 2365                         goto loop;
 2366                 nvp = TAILQ_NEXT(vp, v_nmntvnodes);
 2367 
 2368                 VI_LOCK(vp);
 2369                 mtx_unlock(&mntvnode_mtx);
 2370                 vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, td);
 2371                 /*
 2372                  * Skip over a vnodes marked VV_SYSTEM.
 2373                  */
 2374                 if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
 2375                         VOP_UNLOCK(vp, 0, td);
 2376                         mtx_lock(&mntvnode_mtx);
 2377                         continue;
 2378                 }
 2379                 /*
 2380                  * If WRITECLOSE is set, flush out unlinked but still open
 2381                  * files (even if open only for reading) and regular file
 2382                  * vnodes open for writing.
 2383                  */
 2384                 if (flags & WRITECLOSE) {
 2385                         error = VOP_GETATTR(vp, &vattr, td->td_ucred, td);
 2386                         VI_LOCK(vp);
 2387 
 2388                         if ((vp->v_type == VNON ||
 2389                             (error == 0 && vattr.va_nlink > 0)) &&
 2390                             (vp->v_writecount == 0 || vp->v_type != VREG)) {
 2391                                 VOP_UNLOCK(vp, LK_INTERLOCK, td);
 2392                                 mtx_lock(&mntvnode_mtx);
 2393                                 continue;
 2394                         }
 2395                 } else
 2396                         VI_LOCK(vp);
 2397 
 2398                 VOP_UNLOCK(vp, 0, td);
 2399 
 2400                 /*
 2401                  * With v_usecount == 0, all we need to do is clear out the
 2402                  * vnode data structures and we are done.
 2403                  */
 2404                 if (vp->v_usecount == 0) {
 2405                         vgonel(vp, td);
 2406                         mtx_lock(&mntvnode_mtx);
 2407                         continue;
 2408                 }
 2409 
 2410                 /*
 2411                  * If FORCECLOSE is set, forcibly close the vnode. For block
 2412                  * or character devices, revert to an anonymous device. For
 2413                  * all other files, just kill them.
 2414                  */
 2415                 if (flags & FORCECLOSE) {
 2416                         if (vp->v_type != VCHR) {
 2417                                 vgonel(vp, td);
 2418                         } else {
 2419                                 vclean(vp, 0, td);
 2420                                 VI_UNLOCK(vp);
 2421                                 vp->v_op = spec_vnodeop_p;
 2422                                 insmntque(vp, (struct mount *) 0);
 2423                         }
 2424                         mtx_lock(&mntvnode_mtx);
 2425                         continue;
 2426                 }
 2427 #ifdef DIAGNOSTIC
 2428                 if (busyprt)
 2429                         vprint("vflush: busy vnode", vp);
 2430 #endif
 2431                 VI_UNLOCK(vp);
 2432                 mtx_lock(&mntvnode_mtx);
 2433                 busy++;
 2434         }
 2435         mtx_unlock(&mntvnode_mtx);
 2436         if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
 2437                 /*
 2438                  * If just the root vnode is busy, and if its refcount
 2439                  * is equal to `rootrefs', then go ahead and kill it.
 2440                  */
 2441                 VI_LOCK(rootvp);
 2442                 KASSERT(busy > 0, ("vflush: not busy"));
 2443                 KASSERT(rootvp->v_usecount >= rootrefs, ("vflush: rootrefs"));
 2444                 if (busy == 1 && rootvp->v_usecount == rootrefs) {
 2445                         vgonel(rootvp, td);
 2446                         busy = 0;
 2447                 } else
 2448                         VI_UNLOCK(rootvp);
 2449         }
 2450         if (busy)
 2451                 return (EBUSY);
 2452         for (; rootrefs > 0; rootrefs--)
 2453                 vrele(rootvp);
 2454         return (0);
 2455 }
 2456 
 2457 /*
 2458  * This moves a now (likely recyclable) vnode to the end of the
 2459  * mountlist.  XXX However, it is temporarily disabled until we
 2460  * can clean up ffs_sync() and friends, which have loop restart
 2461  * conditions which this code causes to operate O(N^2).
 2462  */
 2463 static void
 2464 vlruvp(struct vnode *vp)
 2465 {
 2466 #if 0
 2467         struct mount *mp;
 2468 
 2469         if ((mp = vp->v_mount) != NULL) {
 2470                 mtx_lock(&mntvnode_mtx);
 2471                 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 2472                 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 2473                 mtx_unlock(&mntvnode_mtx);
 2474         }
 2475 #endif
 2476 }
 2477 
 2478 /*
 2479  * Disassociate the underlying filesystem from a vnode.
 2480  */
 2481 static void
 2482 vclean(vp, flags, td)
 2483         struct vnode *vp;
 2484         int flags;
 2485         struct thread *td;
 2486 {
 2487         int active;
 2488 
 2489         ASSERT_VI_LOCKED(vp, "vclean");
 2490         /*
 2491          * Check to see if the vnode is in use. If so we have to reference it
 2492          * before we clean it out so that its count cannot fall to zero and
 2493          * generate a race against ourselves to recycle it.
 2494          */
 2495         if ((active = vp->v_usecount))
 2496                 v_incr_usecount(vp, 1);
 2497 
 2498         /*
 2499          * Prevent the vnode from being recycled or brought into use while we
 2500          * clean it out.
 2501          */
 2502         if (vp->v_iflag & VI_XLOCK)
 2503                 panic("vclean: deadlock");
 2504         vp->v_iflag |= VI_XLOCK;
 2505         vp->v_vxproc = curthread;
 2506         /*
 2507          * Even if the count is zero, the VOP_INACTIVE routine may still
 2508          * have the object locked while it cleans it out. The VOP_LOCK
 2509          * ensures that the VOP_INACTIVE routine is done with its work.
 2510          * For active vnodes, it ensures that no other activity can
 2511          * occur while the underlying object is being cleaned out.
 2512          */
 2513         VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK, td);
 2514 
 2515         /*
 2516          * Clean out any buffers associated with the vnode.
 2517          * If the flush fails, just toss the buffers.
 2518          */
 2519         if (flags & DOCLOSE) {
 2520                 struct buf *bp;
 2521                 VI_LOCK(vp);
 2522                 bp = TAILQ_FIRST(&vp->v_dirtyblkhd);
 2523                 VI_UNLOCK(vp);
 2524                 if (bp != NULL)
 2525                         (void) vn_write_suspend_wait(vp, NULL, V_WAIT);
 2526                 if (vinvalbuf(vp, V_SAVE, NOCRED, td, 0, 0) != 0)
 2527                         vinvalbuf(vp, 0, NOCRED, td, 0, 0);
 2528         }
 2529 
 2530         VOP_DESTROYVOBJECT(vp);
 2531 
 2532         /*
 2533          * Any other processes trying to obtain this lock must first
 2534          * wait for VXLOCK to clear, then call the new lock operation.
 2535          */
 2536         VOP_UNLOCK(vp, 0, td);
 2537 
 2538         /*
 2539          * If purging an active vnode, it must be closed and
 2540          * deactivated before being reclaimed. Note that the
 2541          * VOP_INACTIVE will unlock the vnode.
 2542          */
 2543         if (active) {
 2544                 if (flags & DOCLOSE)
 2545                         VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
 2546                 if (vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT, td) != 0)
 2547                         panic("vclean: cannot relock.");
 2548                 VOP_INACTIVE(vp, td);
 2549         }
 2550 
 2551         /*
 2552          * Reclaim the vnode.
 2553          */
 2554         if (VOP_RECLAIM(vp, td))
 2555                 panic("vclean: cannot reclaim");
 2556 
 2557         if (active) {
 2558                 /*
 2559                  * Inline copy of vrele() since VOP_INACTIVE
 2560                  * has already been called.
 2561                  */
 2562                 VI_LOCK(vp);
 2563                 v_incr_usecount(vp, -1);
 2564                 if (vp->v_usecount <= 0) {
 2565 #ifdef DIAGNOSTIC
 2566                         if (vp->v_usecount < 0 || vp->v_writecount != 0) {
 2567                                 vprint("vclean: bad ref count", vp);
 2568                                 panic("vclean: ref cnt");
 2569                         }
 2570 #endif
 2571                         vfree(vp);
 2572                 }
 2573                 VI_UNLOCK(vp);
 2574         }
 2575 
 2576         cache_purge(vp);
 2577         VI_LOCK(vp);
 2578         if (VSHOULDFREE(vp))
 2579                 vfree(vp);
 2580 
 2581         /*
 2582          * Done with purge, reset to the standard lock and
 2583          * notify sleepers of the grim news.
 2584          */
 2585         vp->v_vnlock = &vp->v_lock;
 2586         vp->v_op = dead_vnodeop_p;
 2587         if (vp->v_pollinfo != NULL)
 2588                 vn_pollgone(vp);
 2589         vp->v_tag = "none";
 2590         vp->v_iflag &= ~VI_XLOCK;
 2591         vp->v_vxproc = NULL;
 2592         if (vp->v_iflag & VI_XWANT) {
 2593                 vp->v_iflag &= ~VI_XWANT;
 2594                 wakeup(vp);
 2595         }
 2596 }
 2597 
 2598 /*
 2599  * Eliminate all activity associated with the requested vnode
 2600  * and with all vnodes aliased to the requested vnode.
 2601  */
 2602 int
 2603 vop_revoke(ap)
 2604         struct vop_revoke_args /* {
 2605                 struct vnode *a_vp;
 2606                 int a_flags;
 2607         } */ *ap;
 2608 {
 2609         struct vnode *vp, *vq;
 2610         dev_t dev;
 2611 
 2612         KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
 2613 
 2614         vp = ap->a_vp;
 2615         VI_LOCK(vp);
 2616         /*
 2617          * If a vgone (or vclean) is already in progress,
 2618          * wait until it is done and return.
 2619          */
 2620         if (vp->v_iflag & VI_XLOCK) {
 2621                 vp->v_iflag |= VI_XWANT;
 2622                 msleep(vp, VI_MTX(vp), PINOD | PDROP,
 2623                     "vop_revokeall", 0);
 2624                 return (0);
 2625         }
 2626         VI_UNLOCK(vp);
 2627         dev = vp->v_rdev;
 2628         for (;;) {
 2629                 mtx_lock(&spechash_mtx);
 2630                 vq = SLIST_FIRST(&dev->si_hlist);
 2631                 mtx_unlock(&spechash_mtx);
 2632                 if (!vq)
 2633                         break;
 2634                 vgone(vq);
 2635         }
 2636         return (0);
 2637 }
 2638 
 2639 /*
 2640  * Recycle an unused vnode to the front of the free list.
 2641  * Release the passed interlock if the vnode will be recycled.
 2642  */
 2643 int
 2644 vrecycle(vp, inter_lkp, td)
 2645         struct vnode *vp;
 2646         struct mtx *inter_lkp;
 2647         struct thread *td;
 2648 {
 2649 
 2650         VI_LOCK(vp);
 2651         if (vp->v_usecount == 0) {
 2652                 if (inter_lkp) {
 2653                         mtx_unlock(inter_lkp);
 2654                 }
 2655                 vgonel(vp, td);
 2656                 return (1);
 2657         }
 2658         VI_UNLOCK(vp);
 2659         return (0);
 2660 }
 2661 
 2662 /*
 2663  * Eliminate all activity associated with a vnode
 2664  * in preparation for reuse.
 2665  */
 2666 void
 2667 vgone(vp)
 2668         register struct vnode *vp;
 2669 {
 2670         struct thread *td = curthread;  /* XXX */
 2671 
 2672         VI_LOCK(vp);
 2673         vgonel(vp, td);
 2674 }
 2675 
 2676 /*
 2677  * vgone, with the vp interlock held.
 2678  */
 2679 void
 2680 vgonel(vp, td)
 2681         struct vnode *vp;
 2682         struct thread *td;
 2683 {
 2684         int s;
 2685 
 2686         /*
 2687          * If a vgone (or vclean) is already in progress,
 2688          * wait until it is done and return.
 2689          */
 2690         ASSERT_VI_LOCKED(vp, "vgonel");
 2691         if (vp->v_iflag & VI_XLOCK) {
 2692                 vp->v_iflag |= VI_XWANT;
 2693                 msleep(vp, VI_MTX(vp), PINOD | PDROP, "vgone", 0);
 2694                 return;
 2695         }
 2696 
 2697         /*
 2698          * Clean out the filesystem specific data.
 2699          */
 2700         vclean(vp, DOCLOSE, td);
 2701         VI_UNLOCK(vp);
 2702 
 2703         /*
 2704          * Delete from old mount point vnode list, if on one.
 2705          */
 2706         if (vp->v_mount != NULL)
 2707                 insmntque(vp, (struct mount *)0);
 2708         /*
 2709          * If special device, remove it from special device alias list
 2710          * if it is on one.
 2711          */
 2712         if (vp->v_type == VCHR && vp->v_rdev != NULL && vp->v_rdev != NODEV) {
 2713                 VI_LOCK(vp);
 2714                 mtx_lock(&spechash_mtx);
 2715                 SLIST_REMOVE(&vp->v_rdev->si_hlist, vp, vnode, v_specnext);
 2716                 vp->v_rdev->si_usecount -= vp->v_usecount;
 2717                 mtx_unlock(&spechash_mtx);
 2718                 VI_UNLOCK(vp);
 2719                 vp->v_rdev = NULL;
 2720         }
 2721 
 2722         /*
 2723          * If it is on the freelist and not already at the head,
 2724          * move it to the head of the list. The test of the
 2725          * VDOOMED flag and the reference count of zero is because
 2726          * it will be removed from the free list by getnewvnode,
 2727          * but will not have its reference count incremented until
 2728          * after calling vgone. If the reference count were
 2729          * incremented first, vgone would (incorrectly) try to
 2730          * close the previous instance of the underlying object.
 2731          */
 2732         VI_LOCK(vp);
 2733         if (vp->v_usecount == 0 && !(vp->v_iflag & VI_DOOMED)) {
 2734                 s = splbio();
 2735                 mtx_lock(&vnode_free_list_mtx);
 2736                 if (vp->v_iflag & VI_FREE) {
 2737                         TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
 2738                 } else {
 2739                         vp->v_iflag |= VI_FREE;
 2740                         freevnodes++;
 2741                 }
 2742                 TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
 2743                 mtx_unlock(&vnode_free_list_mtx);
 2744                 splx(s);
 2745         }
 2746 
 2747         vp->v_type = VBAD;
 2748         VI_UNLOCK(vp);
 2749 }
 2750 
 2751 /*
 2752  * Lookup a vnode by device number.
 2753  */
 2754 int
 2755 vfinddev(dev, type, vpp)
 2756         dev_t dev;
 2757         enum vtype type;
 2758         struct vnode **vpp;
 2759 {
 2760         struct vnode *vp;
 2761 
 2762         mtx_lock(&spechash_mtx);
 2763         SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
 2764                 if (type == vp->v_type) {
 2765                         *vpp = vp;
 2766                         mtx_unlock(&spechash_mtx);
 2767                         return (1);
 2768                 }
 2769         }
 2770         mtx_unlock(&spechash_mtx);
 2771         return (0);
 2772 }
 2773 
 2774 /*
 2775  * Calculate the total number of references to a special device.
 2776  */
 2777 int
 2778 vcount(vp)
 2779         struct vnode *vp;
 2780 {
 2781         int count;
 2782 
 2783         mtx_lock(&spechash_mtx);
 2784         count = vp->v_rdev->si_usecount;
 2785         mtx_unlock(&spechash_mtx);
 2786         return (count);
 2787 }
 2788 
 2789 /*
 2790  * Same as above, but using the dev_t as argument
 2791  */
 2792 int
 2793 count_dev(dev)
 2794         dev_t dev;
 2795 {
 2796         struct vnode *vp;
 2797 
 2798         vp = SLIST_FIRST(&dev->si_hlist);
 2799         if (vp == NULL)
 2800                 return (0);
 2801         return(vcount(vp));
 2802 }
 2803 
 2804 /*
 2805  * Print out a description of a vnode.
 2806  */
 2807 static char *typename[] =
 2808 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
 2809 
 2810 void
 2811 vprint(label, vp)
 2812         char *label;
 2813         struct vnode *vp;
 2814 {
 2815         char buf[96];
 2816 
 2817         if (label != NULL)
 2818                 printf("%s: %p: ", label, (void *)vp);
 2819         else
 2820                 printf("%p: ", (void *)vp);
 2821         printf("tag %s, type %s, usecount %d, writecount %d, refcount %d,",
 2822             vp->v_tag, typename[vp->v_type], vp->v_usecount,
 2823             vp->v_writecount, vp->v_holdcnt);
 2824         buf[0] = '\0';
 2825         if (vp->v_vflag & VV_ROOT)
 2826                 strcat(buf, "|VV_ROOT");
 2827         if (vp->v_vflag & VV_TEXT)
 2828                 strcat(buf, "|VV_TEXT");
 2829         if (vp->v_vflag & VV_SYSTEM)
 2830                 strcat(buf, "|VV_SYSTEM");
 2831         if (vp->v_iflag & VI_XLOCK)
 2832                 strcat(buf, "|VI_XLOCK");
 2833         if (vp->v_iflag & VI_XWANT)
 2834                 strcat(buf, "|VI_XWANT");
 2835         if (vp->v_iflag & VI_BWAIT)
 2836                 strcat(buf, "|VI_BWAIT");
 2837         if (vp->v_iflag & VI_DOOMED)
 2838                 strcat(buf, "|VI_DOOMED");
 2839         if (vp->v_iflag & VI_FREE)
 2840                 strcat(buf, "|VI_FREE");
 2841         if (vp->v_vflag & VV_OBJBUF)
 2842                 strcat(buf, "|VV_OBJBUF");
 2843         if (buf[0] != '\0')
 2844                 printf(" flags (%s),", &buf[1]);
 2845         lockmgr_printinfo(vp->v_vnlock);
 2846         printf("\n");
 2847         if (vp->v_data != NULL) {
 2848                 printf("\t");
 2849                 VOP_PRINT(vp);
 2850         }
 2851 }
 2852 
 2853 #ifdef DDB
 2854 #include <ddb/ddb.h>
 2855 /*
 2856  * List all of the locked vnodes in the system.
 2857  * Called when debugging the kernel.
 2858  */
 2859 DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
 2860 {
 2861         struct thread *td = curthread;  /* XXX */
 2862         struct mount *mp, *nmp;
 2863         struct vnode *vp;
 2864 
 2865         printf("Locked vnodes\n");
 2866         mtx_lock(&mountlist_mtx);
 2867         for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
 2868                 if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
 2869                         nmp = TAILQ_NEXT(mp, mnt_list);
 2870                         continue;
 2871                 }
 2872                 mtx_lock(&mntvnode_mtx);
 2873                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2874                         if (VOP_ISLOCKED(vp, NULL))
 2875                                 vprint((char *)0, vp);
 2876                 }
 2877                 mtx_unlock(&mntvnode_mtx);
 2878                 mtx_lock(&mountlist_mtx);
 2879                 nmp = TAILQ_NEXT(mp, mnt_list);
 2880                 vfs_unbusy(mp, td);
 2881         }
 2882         mtx_unlock(&mountlist_mtx);
 2883 }
 2884 #endif
 2885 
 2886 /*
 2887  * Fill in a struct xvfsconf based on a struct vfsconf.
 2888  */
 2889 static void
 2890 vfsconf2x(struct vfsconf *vfsp, struct xvfsconf *xvfsp)
 2891 {
 2892 
 2893         strcpy(xvfsp->vfc_name, vfsp->vfc_name);
 2894         xvfsp->vfc_typenum = vfsp->vfc_typenum;
 2895         xvfsp->vfc_refcount = vfsp->vfc_refcount;
 2896         xvfsp->vfc_flags = vfsp->vfc_flags;
 2897         /*
 2898          * These are unused in userland, we keep them
 2899          * to not break binary compatibility.
 2900          */
 2901         xvfsp->vfc_vfsops = NULL;
 2902         xvfsp->vfc_next = NULL;
 2903 }
 2904 
 2905 static int
 2906 sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
 2907 {
 2908         struct vfsconf *vfsp;
 2909         struct xvfsconf *xvfsp;
 2910         int cnt, error, i;
 2911 
 2912         cnt = 0;
 2913         for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next)
 2914                 cnt++;
 2915         xvfsp = malloc(sizeof(struct xvfsconf) * cnt, M_TEMP, M_WAITOK);
 2916         /*
 2917          * Handle the race that we will have here when struct vfsconf
 2918          * will be locked down by using both cnt and checking vfc_next
 2919          * against NULL to determine the end of the loop.  The race will
 2920          * happen because we will have to unlock before calling malloc().
 2921          * We are protected by Giant for now.
 2922          */
 2923         i = 0;
 2924         for (vfsp = vfsconf; vfsp != NULL && i < cnt; vfsp = vfsp->vfc_next) {
 2925                 vfsconf2x(vfsp, xvfsp + i);
 2926                 i++;
 2927         }
 2928         error = SYSCTL_OUT(req, xvfsp, sizeof(struct xvfsconf) * i);
 2929         free(xvfsp, M_TEMP);
 2930         return (error);
 2931 }
 2932 
 2933 SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
 2934     "S,xvfsconf", "List of all configured filesystems");
 2935 
 2936 /*
 2937  * Top level filesystem related information gathering.
 2938  */
 2939 static int      sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
 2940 
 2941 static int
 2942 vfs_sysctl(SYSCTL_HANDLER_ARGS)
 2943 {
 2944         int *name = (int *)arg1 - 1;    /* XXX */
 2945         u_int namelen = arg2 + 1;       /* XXX */
 2946         struct vfsconf *vfsp;
 2947         struct xvfsconf xvfsp;
 2948 
 2949         printf("WARNING: userland calling deprecated sysctl, "
 2950             "please rebuild world\n");
 2951 
 2952 #if 1 || defined(COMPAT_PRELITE2)
 2953         /* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
 2954         if (namelen == 1)
 2955                 return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
 2956 #endif
 2957 
 2958         switch (name[1]) {
 2959         case VFS_MAXTYPENUM:
 2960                 if (namelen != 2)
 2961                         return (ENOTDIR);
 2962                 return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
 2963         case VFS_CONF:
 2964                 if (namelen != 3)
 2965                         return (ENOTDIR);       /* overloaded */
 2966                 for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
 2967                         if (vfsp->vfc_typenum == name[2])
 2968                                 break;
 2969                 if (vfsp == NULL)
 2970                         return (EOPNOTSUPP);
 2971                 vfsconf2x(vfsp, &xvfsp);
 2972                 return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 2973         }
 2974         return (EOPNOTSUPP);
 2975 }
 2976 
 2977 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP, vfs_sysctl,
 2978         "Generic filesystem");
 2979 
 2980 #if 1 || defined(COMPAT_PRELITE2)
 2981 
 2982 static int
 2983 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
 2984 {
 2985         int error;
 2986         struct vfsconf *vfsp;
 2987         struct ovfsconf ovfs;
 2988 
 2989         for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
 2990                 ovfs.vfc_vfsops = vfsp->vfc_vfsops;     /* XXX used as flag */
 2991                 strcpy(ovfs.vfc_name, vfsp->vfc_name);
 2992                 ovfs.vfc_index = vfsp->vfc_typenum;
 2993                 ovfs.vfc_refcount = vfsp->vfc_refcount;
 2994                 ovfs.vfc_flags = vfsp->vfc_flags;
 2995                 error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
 2996                 if (error)
 2997                         return error;
 2998         }
 2999         return 0;
 3000 }
 3001 
 3002 #endif /* 1 || COMPAT_PRELITE2 */
 3003 
 3004 #define KINFO_VNODESLOP         10
 3005 /*
 3006  * Dump vnode list (via sysctl).
 3007  */
 3008 /* ARGSUSED */
 3009 static int
 3010 sysctl_vnode(SYSCTL_HANDLER_ARGS)
 3011 {
 3012         struct xvnode *xvn;
 3013         struct thread *td = req->td;
 3014         struct mount *mp;
 3015         struct vnode *vp;
 3016         int error, len, n;
 3017 
 3018         /*
 3019          * Stale numvnodes access is not fatal here.
 3020          */
 3021         req->lock = 0;
 3022         len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
 3023         if (!req->oldptr)
 3024                 /* Make an estimate */
 3025                 return (SYSCTL_OUT(req, 0, len));
 3026 
 3027         sysctl_wire_old_buffer(req, 0);
 3028         xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
 3029         n = 0;
 3030         mtx_lock(&mountlist_mtx);
 3031         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 3032                 if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td))
 3033                         continue;
 3034                 mtx_lock(&mntvnode_mtx);
 3035                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3036                         if (n == len)
 3037                                 break;
 3038                         vref(vp);
 3039                         xvn[n].xv_size = sizeof *xvn;
 3040                         xvn[n].xv_vnode = vp;
 3041 #define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
 3042                         XV_COPY(usecount);
 3043                         XV_COPY(writecount);
 3044                         XV_COPY(holdcnt);
 3045                         XV_COPY(id);
 3046                         XV_COPY(mount);
 3047                         XV_COPY(numoutput);
 3048                         XV_COPY(type);
 3049 #undef XV_COPY
 3050                         xvn[n].xv_flag = vp->v_vflag;
 3051 
 3052                         switch (vp->v_type) {
 3053                         case VREG:
 3054                         case VDIR:
 3055                         case VLNK:
 3056                                 xvn[n].xv_dev = vp->v_cachedfs;
 3057                                 xvn[n].xv_ino = vp->v_cachedid;
 3058                                 break;
 3059                         case VBLK:
 3060                         case VCHR:
 3061                                 if (vp->v_rdev == NULL) {
 3062                                         vrele(vp);
 3063                                         continue;
 3064                                 }
 3065                                 xvn[n].xv_dev = dev2udev(vp->v_rdev);
 3066                                 break;
 3067                         case VSOCK:
 3068                                 xvn[n].xv_socket = vp->v_socket;
 3069                                 break;
 3070                         case VFIFO:
 3071                                 xvn[n].xv_fifo = vp->v_fifoinfo;
 3072                                 break;
 3073                         case VNON:
 3074                         case VBAD:
 3075                         default:
 3076                                 /* shouldn't happen? */
 3077                                 vrele(vp);
 3078                                 continue;
 3079                         }
 3080                         vrele(vp);
 3081                         ++n;
 3082                 }
 3083                 mtx_unlock(&mntvnode_mtx);
 3084                 mtx_lock(&mountlist_mtx);
 3085                 vfs_unbusy(mp, td);
 3086                 if (n == len)
 3087                         break;
 3088         }
 3089         mtx_unlock(&mountlist_mtx);
 3090 
 3091         error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
 3092         free(xvn, M_TEMP);
 3093         return (error);
 3094 }
 3095 
 3096 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
 3097         0, 0, sysctl_vnode, "S,xvnode", "");
 3098 
 3099 /*
 3100  * Check to see if a filesystem is mounted on a block device.
 3101  */
 3102 int
 3103 vfs_mountedon(vp)
 3104         struct vnode *vp;
 3105 {
 3106 
 3107         if (vp->v_rdev->si_mountpoint != NULL)
 3108                 return (EBUSY);
 3109         return (0);
 3110 }
 3111 
 3112 /*
 3113  * Unmount all filesystems. The list is traversed in reverse order
 3114  * of mounting to avoid dependencies.
 3115  */
 3116 void
 3117 vfs_unmountall()
 3118 {
 3119         struct mount *mp;
 3120         struct thread *td;
 3121         int error;
 3122 
 3123         if (curthread != NULL)
 3124                 td = curthread;
 3125         else
 3126                 td = FIRST_THREAD_IN_PROC(initproc); /* XXX XXX proc0? */
 3127         /*
 3128          * Since this only runs when rebooting, it is not interlocked.
 3129          */
 3130         while(!TAILQ_EMPTY(&mountlist)) {
 3131                 mp = TAILQ_LAST(&mountlist, mntlist);
 3132                 error = dounmount(mp, MNT_FORCE, td);
 3133                 if (error) {
 3134                         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 3135                         printf("unmount of %s failed (",
 3136                             mp->mnt_stat.f_mntonname);
 3137                         if (error == EBUSY)
 3138                                 printf("BUSY)\n");
 3139                         else
 3140                                 printf("%d)\n", error);
 3141                 } else {
 3142                         /* The unmount has removed mp from the mountlist */
 3143                 }
 3144         }
 3145 }
 3146 
 3147 /*
 3148  * perform msync on all vnodes under a mount point
 3149  * the mount point must be locked.
 3150  */
 3151 void
 3152 vfs_msync(struct mount *mp, int flags)
 3153 {
 3154         struct vnode *vp, *nvp;
 3155         struct vm_object *obj;
 3156         int tries;
 3157 
 3158         GIANT_REQUIRED;
 3159 
 3160         tries = 5;
 3161         mtx_lock(&mntvnode_mtx);
 3162 loop:
 3163         for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp != NULL; vp = nvp) {
 3164                 if (vp->v_mount != mp) {
 3165                         if (--tries > 0)
 3166                                 goto loop;
 3167                         break;
 3168                 }
 3169                 nvp = TAILQ_NEXT(vp, v_nmntvnodes);
 3170 
 3171                 VI_LOCK(vp);
 3172                 if (vp->v_iflag & VI_XLOCK) {   /* XXX: what if MNT_WAIT? */
 3173                         VI_UNLOCK(vp);
 3174                         continue;
 3175                 }
 3176 
 3177                 if ((vp->v_iflag & VI_OBJDIRTY) &&
 3178                     (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
 3179                         mtx_unlock(&mntvnode_mtx);
 3180                         if (!vget(vp,
 3181                             LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
 3182                             curthread)) {
 3183                                 if (vp->v_vflag & VV_NOSYNC) {  /* unlinked */
 3184                                         vput(vp);
 3185                                         mtx_lock(&mntvnode_mtx);
 3186                                         continue;
 3187                                 }
 3188 
 3189                                 if (VOP_GETVOBJECT(vp, &obj) == 0) {
 3190                                         vm_object_page_clean(obj, 0, 0,
 3191                                             flags == MNT_WAIT ?
 3192                                             OBJPC_SYNC : OBJPC_NOSYNC);
 3193                                 }
 3194                                 vput(vp);
 3195                         }
 3196                         mtx_lock(&mntvnode_mtx);
 3197                         if (TAILQ_NEXT(vp, v_nmntvnodes) != nvp) {
 3198                                 if (--tries > 0)
 3199                                         goto loop;
 3200                                 break;
 3201                         }
 3202                 } else
 3203                         VI_UNLOCK(vp);
 3204         }
 3205         mtx_unlock(&mntvnode_mtx);
 3206 }
 3207 
 3208 /*
 3209  * Create the VM object needed for VMIO and mmap support.  This
 3210  * is done for all VREG files in the system.  Some filesystems might
 3211  * afford the additional metadata buffering capability of the
 3212  * VMIO code by making the device node be VMIO mode also.
 3213  *
 3214  * vp must be locked when vfs_object_create is called.
 3215  */
 3216 int
 3217 vfs_object_create(vp, td, cred)
 3218         struct vnode *vp;
 3219         struct thread *td;
 3220         struct ucred *cred;
 3221 {
 3222         GIANT_REQUIRED;
 3223         return (VOP_CREATEVOBJECT(vp, cred, td));
 3224 }
 3225 
 3226 /*
 3227  * Mark a vnode as free, putting it up for recycling.
 3228  */
 3229 void
 3230 vfree(vp)
 3231         struct vnode *vp;
 3232 {
 3233         int s;
 3234 
 3235         ASSERT_VI_LOCKED(vp, "vfree");
 3236         s = splbio();
 3237         mtx_lock(&vnode_free_list_mtx);
 3238         KASSERT((vp->v_iflag & VI_FREE) == 0, ("vnode already free"));
 3239         if (vp->v_iflag & VI_AGE) {
 3240                 TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
 3241         } else {
 3242                 TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 3243         }
 3244         freevnodes++;
 3245         mtx_unlock(&vnode_free_list_mtx);
 3246         vp->v_iflag &= ~VI_AGE;
 3247         vp->v_iflag |= VI_FREE;
 3248         splx(s);
 3249 }
 3250 
 3251 /*
 3252  * Opposite of vfree() - mark a vnode as in use.
 3253  */
 3254 void
 3255 vbusy(vp)
 3256         struct vnode *vp;
 3257 {
 3258         int s;
 3259 
 3260         s = splbio();
 3261         ASSERT_VI_LOCKED(vp, "vbusy");
 3262         KASSERT((vp->v_iflag & VI_FREE) != 0, ("vnode not free"));
 3263 
 3264         mtx_lock(&vnode_free_list_mtx);
 3265         TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
 3266         freevnodes--;
 3267         mtx_unlock(&vnode_free_list_mtx);
 3268 
 3269         vp->v_iflag &= ~(VI_FREE|VI_AGE);
 3270         splx(s);
 3271 }
 3272 
 3273 /*
 3274  * Record a process's interest in events which might happen to
 3275  * a vnode.  Because poll uses the historic select-style interface
 3276  * internally, this routine serves as both the ``check for any
 3277  * pending events'' and the ``record my interest in future events''
 3278  * functions.  (These are done together, while the lock is held,
 3279  * to avoid race conditions.)
 3280  */
 3281 int
 3282 vn_pollrecord(vp, td, events)
 3283         struct vnode *vp;
 3284         struct thread *td;
 3285         short events;
 3286 {
 3287 
 3288         if (vp->v_pollinfo == NULL)
 3289                 v_addpollinfo(vp);
 3290         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3291         if (vp->v_pollinfo->vpi_revents & events) {
 3292                 /*
 3293                  * This leaves events we are not interested
 3294                  * in available for the other process which
 3295                  * which presumably had requested them
 3296                  * (otherwise they would never have been
 3297                  * recorded).
 3298                  */
 3299                 events &= vp->v_pollinfo->vpi_revents;
 3300                 vp->v_pollinfo->vpi_revents &= ~events;
 3301 
 3302                 mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3303                 return events;
 3304         }
 3305         vp->v_pollinfo->vpi_events |= events;
 3306         selrecord(td, &vp->v_pollinfo->vpi_selinfo);
 3307         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3308         return 0;
 3309 }
 3310 
 3311 /*
 3312  * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
 3313  * it is possible for us to miss an event due to race conditions, but
 3314  * that condition is expected to be rare, so for the moment it is the
 3315  * preferred interface.
 3316  */
 3317 void
 3318 vn_pollevent(vp, events)
 3319         struct vnode *vp;
 3320         short events;
 3321 {
 3322 
 3323         if (vp->v_pollinfo == NULL)
 3324                 v_addpollinfo(vp);
 3325         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3326         if (vp->v_pollinfo->vpi_events & events) {
 3327                 /*
 3328                  * We clear vpi_events so that we don't
 3329                  * call selwakeup() twice if two events are
 3330                  * posted before the polling process(es) is
 3331                  * awakened.  This also ensures that we take at
 3332                  * most one selwakeup() if the polling process
 3333                  * is no longer interested.  However, it does
 3334                  * mean that only one event can be noticed at
 3335                  * a time.  (Perhaps we should only clear those
 3336                  * event bits which we note?) XXX
 3337                  */
 3338                 vp->v_pollinfo->vpi_events = 0; /* &= ~events ??? */
 3339                 vp->v_pollinfo->vpi_revents |= events;
 3340                 selwakeup(&vp->v_pollinfo->vpi_selinfo);
 3341         }
 3342         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3343 }
 3344 
 3345 /*
 3346  * Wake up anyone polling on vp because it is being revoked.
 3347  * This depends on dead_poll() returning POLLHUP for correct
 3348  * behavior.
 3349  */
 3350 void
 3351 vn_pollgone(vp)
 3352         struct vnode *vp;
 3353 {
 3354 
 3355         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3356         VN_KNOTE(vp, NOTE_REVOKE);
 3357         if (vp->v_pollinfo->vpi_events) {
 3358                 vp->v_pollinfo->vpi_events = 0;
 3359                 selwakeup(&vp->v_pollinfo->vpi_selinfo);
 3360         }
 3361         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3362 }
 3363 
 3364 
 3365 
 3366 /*
 3367  * Routine to create and manage a filesystem syncer vnode.
 3368  */
 3369 #define sync_close ((int (*)(struct  vop_close_args *))nullop)
 3370 static int      sync_fsync(struct  vop_fsync_args *);
 3371 static int      sync_inactive(struct  vop_inactive_args *);
 3372 static int      sync_reclaim(struct  vop_reclaim_args *);
 3373 static int      sync_print(struct vop_print_args *);
 3374 
 3375 static vop_t **sync_vnodeop_p;
 3376 static struct vnodeopv_entry_desc sync_vnodeop_entries[] = {
 3377         { &vop_default_desc,    (vop_t *) vop_eopnotsupp },
 3378         { &vop_close_desc,      (vop_t *) sync_close },         /* close */
 3379         { &vop_fsync_desc,      (vop_t *) sync_fsync },         /* fsync */
 3380         { &vop_inactive_desc,   (vop_t *) sync_inactive },      /* inactive */
 3381         { &vop_reclaim_desc,    (vop_t *) sync_reclaim },       /* reclaim */
 3382         { &vop_lock_desc,       (vop_t *) vop_stdlock },        /* lock */
 3383         { &vop_unlock_desc,     (vop_t *) vop_stdunlock },      /* unlock */
 3384         { &vop_print_desc,      (vop_t *) sync_print },         /* print */
 3385         { &vop_islocked_desc,   (vop_t *) vop_stdislocked },    /* islocked */
 3386         { NULL, NULL }
 3387 };
 3388 static struct vnodeopv_desc sync_vnodeop_opv_desc =
 3389         { &sync_vnodeop_p, sync_vnodeop_entries };
 3390 
 3391 VNODEOP_SET(sync_vnodeop_opv_desc);
 3392 
 3393 /*
 3394  * Create a new filesystem syncer vnode for the specified mount point.
 3395  */
 3396 int
 3397 vfs_allocate_syncvnode(mp)
 3398         struct mount *mp;
 3399 {
 3400         struct vnode *vp;
 3401         static long start, incr, next;
 3402         int error;
 3403 
 3404         /* Allocate a new vnode */
 3405         if ((error = getnewvnode("vfs", mp, sync_vnodeop_p, &vp)) != 0) {
 3406                 mp->mnt_syncer = NULL;
 3407                 return (error);
 3408         }
 3409         vp->v_type = VNON;
 3410         /*
 3411          * Place the vnode onto the syncer worklist. We attempt to
 3412          * scatter them about on the list so that they will go off
 3413          * at evenly distributed times even if all the filesystems
 3414          * are mounted at once.
 3415          */
 3416         next += incr;
 3417         if (next == 0 || next > syncer_maxdelay) {
 3418                 start /= 2;
 3419                 incr /= 2;
 3420                 if (start == 0) {
 3421                         start = syncer_maxdelay / 2;
 3422                         incr = syncer_maxdelay;
 3423                 }
 3424                 next = start;
 3425         }
 3426         VI_LOCK(vp);
 3427         vn_syncer_add_to_worklist(vp, syncdelay > 0 ? next % syncdelay : 0);
 3428         VI_UNLOCK(vp);
 3429         mp->mnt_syncer = vp;
 3430         return (0);
 3431 }
 3432 
 3433 /*
 3434  * Do a lazy sync of the filesystem.
 3435  */
 3436 static int
 3437 sync_fsync(ap)
 3438         struct vop_fsync_args /* {
 3439                 struct vnode *a_vp;
 3440                 struct ucred *a_cred;
 3441                 int a_waitfor;
 3442                 struct thread *a_td;
 3443         } */ *ap;
 3444 {
 3445         struct vnode *syncvp = ap->a_vp;
 3446         struct mount *mp = syncvp->v_mount;
 3447         struct thread *td = ap->a_td;
 3448         int error, asyncflag;
 3449 
 3450         /*
 3451          * We only need to do something if this is a lazy evaluation.
 3452          */
 3453         if (ap->a_waitfor != MNT_LAZY)
 3454                 return (0);
 3455 
 3456         /*
 3457          * Move ourselves to the back of the sync list.
 3458          */
 3459         VI_LOCK(syncvp);
 3460         vn_syncer_add_to_worklist(syncvp, syncdelay);
 3461         VI_UNLOCK(syncvp);
 3462 
 3463         /*
 3464          * Walk the list of vnodes pushing all that are dirty and
 3465          * not already on the sync list.
 3466          */
 3467         mtx_lock(&mountlist_mtx);
 3468         if (vfs_busy(mp, LK_EXCLUSIVE | LK_NOWAIT, &mountlist_mtx, td) != 0) {
 3469                 mtx_unlock(&mountlist_mtx);
 3470                 return (0);
 3471         }
 3472         if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
 3473                 vfs_unbusy(mp, td);
 3474                 return (0);
 3475         }
 3476         asyncflag = mp->mnt_flag & MNT_ASYNC;
 3477         mp->mnt_flag &= ~MNT_ASYNC;
 3478         vfs_msync(mp, MNT_NOWAIT);
 3479         error = VFS_SYNC(mp, MNT_LAZY, ap->a_cred, td);
 3480         if (asyncflag)
 3481                 mp->mnt_flag |= MNT_ASYNC;
 3482         vn_finished_write(mp);
 3483         vfs_unbusy(mp, td);
 3484         return (error);
 3485 }
 3486 
 3487 /*
 3488  * The syncer vnode is no referenced.
 3489  */
 3490 static int
 3491 sync_inactive(ap)
 3492         struct vop_inactive_args /* {
 3493                 struct vnode *a_vp;
 3494                 struct thread *a_td;
 3495         } */ *ap;
 3496 {
 3497 
 3498         VOP_UNLOCK(ap->a_vp, 0, ap->a_td);
 3499         vgone(ap->a_vp);
 3500         return (0);
 3501 }
 3502 
 3503 /*
 3504  * The syncer vnode is no longer needed and is being decommissioned.
 3505  *
 3506  * Modifications to the worklist must be protected at splbio().
 3507  */
 3508 static int
 3509 sync_reclaim(ap)
 3510         struct vop_reclaim_args /* {
 3511                 struct vnode *a_vp;
 3512         } */ *ap;
 3513 {
 3514         struct vnode *vp = ap->a_vp;
 3515         int s;
 3516 
 3517         s = splbio();
 3518         vp->v_mount->mnt_syncer = NULL;
 3519         VI_LOCK(vp);
 3520         if (vp->v_iflag & VI_ONWORKLST) {
 3521                 mtx_lock(&sync_mtx);
 3522                 LIST_REMOVE(vp, v_synclist);
 3523                 mtx_unlock(&sync_mtx);
 3524                 vp->v_iflag &= ~VI_ONWORKLST;
 3525         }
 3526         VI_UNLOCK(vp);
 3527         splx(s);
 3528 
 3529         return (0);
 3530 }
 3531 
 3532 /*
 3533  * Print out a syncer vnode.
 3534  */
 3535 static int
 3536 sync_print(ap)
 3537         struct vop_print_args /* {
 3538                 struct vnode *a_vp;
 3539         } */ *ap;
 3540 {
 3541         struct vnode *vp = ap->a_vp;
 3542 
 3543         printf("syncer vnode");
 3544         if (vp->v_vnlock != NULL)
 3545                 lockmgr_printinfo(vp->v_vnlock);
 3546         printf("\n");
 3547         return (0);
 3548 }
 3549 
 3550 /*
 3551  * extract the dev_t from a VCHR
 3552  */
 3553 dev_t
 3554 vn_todev(vp)
 3555         struct vnode *vp;
 3556 {
 3557         if (vp->v_type != VCHR)
 3558                 return (NODEV);
 3559         return (vp->v_rdev);
 3560 }
 3561 
 3562 /*
 3563  * Check if vnode represents a disk device
 3564  */
 3565 int
 3566 vn_isdisk(vp, errp)
 3567         struct vnode *vp;
 3568         int *errp;
 3569 {
 3570         struct cdevsw *cdevsw;
 3571 
 3572         if (vp->v_type != VCHR) {
 3573                 if (errp != NULL)
 3574                         *errp = ENOTBLK;
 3575                 return (0);
 3576         }
 3577         if (vp->v_rdev == NULL) {
 3578                 if (errp != NULL)
 3579                         *errp = ENXIO;
 3580                 return (0);
 3581         }
 3582         cdevsw = devsw(vp->v_rdev);
 3583         if (cdevsw == NULL) {
 3584                 if (errp != NULL)
 3585                         *errp = ENXIO;
 3586                 return (0);
 3587         }
 3588         if (!(cdevsw->d_flags & D_DISK)) {
 3589                 if (errp != NULL)
 3590                         *errp = ENOTBLK;
 3591                 return (0);
 3592         }
 3593         if (errp != NULL)
 3594                 *errp = 0;
 3595         return (1);
 3596 }
 3597 
 3598 /*
 3599  * Free data allocated by namei(); see namei(9) for details.
 3600  */
 3601 void
 3602 NDFREE(ndp, flags)
 3603      struct nameidata *ndp;
 3604      const uint flags;
 3605 {
 3606         if (!(flags & NDF_NO_FREE_PNBUF) &&
 3607             (ndp->ni_cnd.cn_flags & HASBUF)) {
 3608                 uma_zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
 3609                 ndp->ni_cnd.cn_flags &= ~HASBUF;
 3610         }
 3611         if (!(flags & NDF_NO_DVP_UNLOCK) &&
 3612             (ndp->ni_cnd.cn_flags & LOCKPARENT) &&
 3613             ndp->ni_dvp != ndp->ni_vp)
 3614                 VOP_UNLOCK(ndp->ni_dvp, 0, ndp->ni_cnd.cn_thread);
 3615         if (!(flags & NDF_NO_DVP_RELE) &&
 3616             (ndp->ni_cnd.cn_flags & (LOCKPARENT|WANTPARENT))) {
 3617                 vrele(ndp->ni_dvp);
 3618                 ndp->ni_dvp = NULL;
 3619         }
 3620         if (!(flags & NDF_NO_VP_UNLOCK) &&
 3621             (ndp->ni_cnd.cn_flags & LOCKLEAF) && ndp->ni_vp)
 3622                 VOP_UNLOCK(ndp->ni_vp, 0, ndp->ni_cnd.cn_thread);
 3623         if (!(flags & NDF_NO_VP_RELE) &&
 3624             ndp->ni_vp) {
 3625                 vrele(ndp->ni_vp);
 3626                 ndp->ni_vp = NULL;
 3627         }
 3628         if (!(flags & NDF_NO_STARTDIR_RELE) &&
 3629             (ndp->ni_cnd.cn_flags & SAVESTART)) {
 3630                 vrele(ndp->ni_startdir);
 3631                 ndp->ni_startdir = NULL;
 3632         }
 3633 }
 3634 
 3635 /*
 3636  * Common filesystem object access control check routine.  Accepts a
 3637  * vnode's type, "mode", uid and gid, requested access mode, credentials,
 3638  * and optional call-by-reference privused argument allowing vaccess()
 3639  * to indicate to the caller whether privilege was used to satisfy the
 3640  * request (obsoleted).  Returns 0 on success, or an errno on failure.
 3641  */
 3642 int
 3643 vaccess(type, file_mode, file_uid, file_gid, acc_mode, cred, privused)
 3644         enum vtype type;
 3645         mode_t file_mode;
 3646         uid_t file_uid;
 3647         gid_t file_gid;
 3648         mode_t acc_mode;
 3649         struct ucred *cred;
 3650         int *privused;
 3651 {
 3652         mode_t dac_granted;
 3653 #ifdef CAPABILITIES
 3654         mode_t cap_granted;
 3655 #endif
 3656 
 3657         /*
 3658          * Look for a normal, non-privileged way to access the file/directory
 3659          * as requested.  If it exists, go with that.
 3660          */
 3661 
 3662         if (privused != NULL)
 3663                 *privused = 0;
 3664 
 3665         dac_granted = 0;
 3666 
 3667         /* Check the owner. */
 3668         if (cred->cr_uid == file_uid) {
 3669                 dac_granted |= VADMIN;
 3670                 if (file_mode & S_IXUSR)
 3671                         dac_granted |= VEXEC;
 3672                 if (file_mode & S_IRUSR)
 3673                         dac_granted |= VREAD;
 3674                 if (file_mode & S_IWUSR)
 3675                         dac_granted |= (VWRITE | VAPPEND);
 3676 
 3677                 if ((acc_mode & dac_granted) == acc_mode)
 3678                         return (0);
 3679 
 3680                 goto privcheck;
 3681         }
 3682 
 3683         /* Otherwise, check the groups (first match) */
 3684         if (groupmember(file_gid, cred)) {
 3685                 if (file_mode & S_IXGRP)
 3686                         dac_granted |= VEXEC;
 3687                 if (file_mode & S_IRGRP)
 3688                         dac_granted |= VREAD;
 3689                 if (file_mode & S_IWGRP)
 3690                         dac_granted |= (VWRITE | VAPPEND);
 3691 
 3692                 if ((acc_mode & dac_granted) == acc_mode)
 3693                         return (0);
 3694 
 3695                 goto privcheck;
 3696         }
 3697 
 3698         /* Otherwise, check everyone else. */
 3699         if (file_mode & S_IXOTH)
 3700                 dac_granted |= VEXEC;
 3701         if (file_mode & S_IROTH)
 3702                 dac_granted |= VREAD;
 3703         if (file_mode & S_IWOTH)
 3704                 dac_granted |= (VWRITE | VAPPEND);
 3705         if ((acc_mode & dac_granted) == acc_mode)
 3706                 return (0);
 3707 
 3708 privcheck:
 3709         if (!suser_cred(cred, PRISON_ROOT)) {
 3710                 /* XXX audit: privilege used */
 3711                 if (privused != NULL)
 3712                         *privused = 1;
 3713                 return (0);
 3714         }
 3715 
 3716 #ifdef CAPABILITIES
 3717         /*
 3718          * Build a capability mask to determine if the set of capabilities
 3719          * satisfies the requirements when combined with the granted mask
 3720          * from above.
 3721          * For each capability, if the capability is required, bitwise
 3722          * or the request type onto the cap_granted mask.
 3723          */
 3724         cap_granted = 0;
 3725 
 3726         if (type == VDIR) {
 3727                 /*
 3728                  * For directories, use CAP_DAC_READ_SEARCH to satisfy
 3729                  * VEXEC requests, instead of CAP_DAC_EXECUTE.
 3730                  */
 3731                 if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3732                     !cap_check(cred, NULL, CAP_DAC_READ_SEARCH, PRISON_ROOT))
 3733                         cap_granted |= VEXEC;
 3734         } else {
 3735                 if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3736                     !cap_check(cred, NULL, CAP_DAC_EXECUTE, PRISON_ROOT))
 3737                         cap_granted |= VEXEC;
 3738         }
 3739 
 3740         if ((acc_mode & VREAD) && ((dac_granted & VREAD) == 0) &&
 3741             !cap_check(cred, NULL, CAP_DAC_READ_SEARCH, PRISON_ROOT))
 3742                 cap_granted |= VREAD;
 3743 
 3744         if ((acc_mode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
 3745             !cap_check(cred, NULL, CAP_DAC_WRITE, PRISON_ROOT))
 3746                 cap_granted |= (VWRITE | VAPPEND);
 3747 
 3748         if ((acc_mode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
 3749             !cap_check(cred, NULL, CAP_FOWNER, PRISON_ROOT))
 3750                 cap_granted |= VADMIN;
 3751 
 3752         if ((acc_mode & (cap_granted | dac_granted)) == acc_mode) {
 3753                 /* XXX audit: privilege used */
 3754                 if (privused != NULL)
 3755                         *privused = 1;
 3756                 return (0);
 3757         }
 3758 #endif
 3759 
 3760         return ((acc_mode & VADMIN) ? EPERM : EACCES);
 3761 }
 3762 
 3763 /*
 3764  * Credential check based on process requesting service, and per-attribute
 3765  * permissions.
 3766  */
 3767 int
 3768 extattr_check_cred(struct vnode *vp, int attrnamespace,
 3769     struct ucred *cred, struct thread *td, int access)
 3770 {
 3771 
 3772         /*
 3773          * Kernel-invoked always succeeds.
 3774          */
 3775         if (cred == NOCRED)
 3776                 return (0);
 3777 
 3778         /*
 3779          * Do not allow privileged processes in jail to directly
 3780          * manipulate system attributes.
 3781          *
 3782          * XXX What capability should apply here?
 3783          * Probably CAP_SYS_SETFFLAG.
 3784          */
 3785         switch (attrnamespace) {
 3786         case EXTATTR_NAMESPACE_SYSTEM:
 3787                 /* Potentially should be: return (EPERM); */
 3788                 return (suser_cred(cred, 0));
 3789         case EXTATTR_NAMESPACE_USER:
 3790                 return (VOP_ACCESS(vp, access, cred, td));
 3791         default:
 3792                 return (EPERM);
 3793         }
 3794 }

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