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  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)vfs_subr.c  8.31 (Berkeley) 5/26/95
   35  */
   36 
   37 /*
   38  * External virtual filesystem routines
   39  */
   40 
   41 #include <sys/cdefs.h>
   42 __FBSDID("$FreeBSD: releng/10.0/sys/kern/vfs_subr.c 256211 2013-10-09 18:43:29Z kib $");
   43 
   44 #include "opt_compat.h"
   45 #include "opt_ddb.h"
   46 #include "opt_watchdog.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/condvar.h>
   53 #include <sys/conf.h>
   54 #include <sys/dirent.h>
   55 #include <sys/event.h>
   56 #include <sys/eventhandler.h>
   57 #include <sys/extattr.h>
   58 #include <sys/file.h>
   59 #include <sys/fcntl.h>
   60 #include <sys/jail.h>
   61 #include <sys/kdb.h>
   62 #include <sys/kernel.h>
   63 #include <sys/kthread.h>
   64 #include <sys/lockf.h>
   65 #include <sys/malloc.h>
   66 #include <sys/mount.h>
   67 #include <sys/namei.h>
   68 #include <sys/pctrie.h>
   69 #include <sys/priv.h>
   70 #include <sys/reboot.h>
   71 #include <sys/rwlock.h>
   72 #include <sys/sched.h>
   73 #include <sys/sleepqueue.h>
   74 #include <sys/smp.h>
   75 #include <sys/stat.h>
   76 #include <sys/sysctl.h>
   77 #include <sys/syslog.h>
   78 #include <sys/vmmeter.h>
   79 #include <sys/vnode.h>
   80 #include <sys/watchdog.h>
   81 
   82 #include <machine/stdarg.h>
   83 
   84 #include <security/mac/mac_framework.h>
   85 
   86 #include <vm/vm.h>
   87 #include <vm/vm_object.h>
   88 #include <vm/vm_extern.h>
   89 #include <vm/pmap.h>
   90 #include <vm/vm_map.h>
   91 #include <vm/vm_page.h>
   92 #include <vm/vm_kern.h>
   93 #include <vm/uma.h>
   94 
   95 #ifdef DDB
   96 #include <ddb/ddb.h>
   97 #endif
   98 
   99 static void     delmntque(struct vnode *vp);
  100 static int      flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo,
  101                     int slpflag, int slptimeo);
  102 static void     syncer_shutdown(void *arg, int howto);
  103 static int      vtryrecycle(struct vnode *vp);
  104 static void     v_incr_usecount(struct vnode *);
  105 static void     v_decr_usecount(struct vnode *);
  106 static void     v_decr_useonly(struct vnode *);
  107 static void     v_upgrade_usecount(struct vnode *);
  108 static void     vnlru_free(int);
  109 static void     vgonel(struct vnode *);
  110 static void     vfs_knllock(void *arg);
  111 static void     vfs_knlunlock(void *arg);
  112 static void     vfs_knl_assert_locked(void *arg);
  113 static void     vfs_knl_assert_unlocked(void *arg);
  114 static void     destroy_vpollinfo(struct vpollinfo *vi);
  115 
  116 /*
  117  * Number of vnodes in existence.  Increased whenever getnewvnode()
  118  * allocates a new vnode, decreased in vdropl() for VI_DOOMED vnode.
  119  */
  120 static unsigned long    numvnodes;
  121 
  122 SYSCTL_ULONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
  123     "Number of vnodes in existence");
  124 
  125 /*
  126  * Conversion tables for conversion from vnode types to inode formats
  127  * and back.
  128  */
  129 enum vtype iftovt_tab[16] = {
  130         VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
  131         VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
  132 };
  133 int vttoif_tab[10] = {
  134         0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
  135         S_IFSOCK, S_IFIFO, S_IFMT, S_IFMT
  136 };
  137 
  138 /*
  139  * List of vnodes that are ready for recycling.
  140  */
  141 static TAILQ_HEAD(freelst, vnode) vnode_free_list;
  142 
  143 /*
  144  * Free vnode target.  Free vnodes may simply be files which have been stat'd
  145  * but not read.  This is somewhat common, and a small cache of such files
  146  * should be kept to avoid recreation costs.
  147  */
  148 static u_long wantfreevnodes;
  149 SYSCTL_ULONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
  150 /* Number of vnodes in the free list. */
  151 static u_long freevnodes;
  152 SYSCTL_ULONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0,
  153     "Number of vnodes in the free list");
  154 
  155 static int vlru_allow_cache_src;
  156 SYSCTL_INT(_vfs, OID_AUTO, vlru_allow_cache_src, CTLFLAG_RW,
  157     &vlru_allow_cache_src, 0, "Allow vlru to reclaim source vnode");
  158 
  159 /*
  160  * Various variables used for debugging the new implementation of
  161  * reassignbuf().
  162  * XXX these are probably of (very) limited utility now.
  163  */
  164 static int reassignbufcalls;
  165 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0,
  166     "Number of calls to reassignbuf");
  167 
  168 /*
  169  * Cache for the mount type id assigned to NFS.  This is used for
  170  * special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
  171  */
  172 int     nfs_mount_type = -1;
  173 
  174 /* To keep more than one thread at a time from running vfs_getnewfsid */
  175 static struct mtx mntid_mtx;
  176 
  177 /*
  178  * Lock for any access to the following:
  179  *      vnode_free_list
  180  *      numvnodes
  181  *      freevnodes
  182  */
  183 static struct mtx vnode_free_list_mtx;
  184 
  185 /* Publicly exported FS */
  186 struct nfs_public nfs_pub;
  187 
  188 static uma_zone_t buf_trie_zone;
  189 
  190 /* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
  191 static uma_zone_t vnode_zone;
  192 static uma_zone_t vnodepoll_zone;
  193 
  194 /*
  195  * The workitem queue.
  196  *
  197  * It is useful to delay writes of file data and filesystem metadata
  198  * for tens of seconds so that quickly created and deleted files need
  199  * not waste disk bandwidth being created and removed. To realize this,
  200  * we append vnodes to a "workitem" queue. When running with a soft
  201  * updates implementation, most pending metadata dependencies should
  202  * not wait for more than a few seconds. Thus, mounted on block devices
  203  * are delayed only about a half the time that file data is delayed.
  204  * Similarly, directory updates are more critical, so are only delayed
  205  * about a third the time that file data is delayed. Thus, there are
  206  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
  207  * one each second (driven off the filesystem syncer process). The
  208  * syncer_delayno variable indicates the next queue that is to be processed.
  209  * Items that need to be processed soon are placed in this queue:
  210  *
  211  *      syncer_workitem_pending[syncer_delayno]
  212  *
  213  * A delay of fifteen seconds is done by placing the request fifteen
  214  * entries later in the queue:
  215  *
  216  *      syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
  217  *
  218  */
  219 static int syncer_delayno;
  220 static long syncer_mask;
  221 LIST_HEAD(synclist, bufobj);
  222 static struct synclist *syncer_workitem_pending;
  223 /*
  224  * The sync_mtx protects:
  225  *      bo->bo_synclist
  226  *      sync_vnode_count
  227  *      syncer_delayno
  228  *      syncer_state
  229  *      syncer_workitem_pending
  230  *      syncer_worklist_len
  231  *      rushjob
  232  */
  233 static struct mtx sync_mtx;
  234 static struct cv sync_wakeup;
  235 
  236 #define SYNCER_MAXDELAY         32
  237 static int syncer_maxdelay = SYNCER_MAXDELAY;   /* maximum delay time */
  238 static int syncdelay = 30;              /* max time to delay syncing data */
  239 static int filedelay = 30;              /* time to delay syncing files */
  240 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0,
  241     "Time to delay syncing files (in seconds)");
  242 static int dirdelay = 29;               /* time to delay syncing directories */
  243 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0,
  244     "Time to delay syncing directories (in seconds)");
  245 static int metadelay = 28;              /* time to delay syncing metadata */
  246 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0,
  247     "Time to delay syncing metadata (in seconds)");
  248 static int rushjob;             /* number of slots to run ASAP */
  249 static int stat_rush_requests;  /* number of times I/O speeded up */
  250 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0,
  251     "Number of times I/O speeded up (rush requests)");
  252 
  253 /*
  254  * When shutting down the syncer, run it at four times normal speed.
  255  */
  256 #define SYNCER_SHUTDOWN_SPEEDUP         4
  257 static int sync_vnode_count;
  258 static int syncer_worklist_len;
  259 static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
  260     syncer_state;
  261 
  262 /*
  263  * Number of vnodes we want to exist at any one time.  This is mostly used
  264  * to size hash tables in vnode-related code.  It is normally not used in
  265  * getnewvnode(), as wantfreevnodes is normally nonzero.)
  266  *
  267  * XXX desiredvnodes is historical cruft and should not exist.
  268  */
  269 int desiredvnodes;
  270 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
  271     &desiredvnodes, 0, "Maximum number of vnodes");
  272 SYSCTL_ULONG(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
  273     &wantfreevnodes, 0, "Minimum number of vnodes (legacy)");
  274 static int vnlru_nowhere;
  275 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
  276     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
  277 
  278 /*
  279  * Macros to control when a vnode is freed and recycled.  All require
  280  * the vnode interlock.
  281  */
  282 #define VCANRECYCLE(vp) (((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  283 #define VSHOULDFREE(vp) (!((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  284 #define VSHOULDBUSY(vp) (((vp)->v_iflag & VI_FREE) && (vp)->v_holdcnt)
  285 
  286 /* Shift count for (uintptr_t)vp to initialize vp->v_hash. */
  287 static int vnsz2log;
  288 
  289 /*
  290  * Support for the bufobj clean & dirty pctrie.
  291  */
  292 static void *
  293 buf_trie_alloc(struct pctrie *ptree)
  294 {
  295 
  296         return uma_zalloc(buf_trie_zone, M_NOWAIT);
  297 }
  298 
  299 static void
  300 buf_trie_free(struct pctrie *ptree, void *node)
  301 {
  302 
  303         uma_zfree(buf_trie_zone, node);
  304 }
  305 PCTRIE_DEFINE(BUF, buf, b_lblkno, buf_trie_alloc, buf_trie_free);
  306 
  307 /*
  308  * Initialize the vnode management data structures.
  309  *
  310  * Reevaluate the following cap on the number of vnodes after the physical
  311  * memory size exceeds 512GB.  In the limit, as the physical memory size
  312  * grows, the ratio of physical pages to vnodes approaches sixteen to one.
  313  */
  314 #ifndef MAXVNODES_MAX
  315 #define MAXVNODES_MAX   (512 * (1024 * 1024 * 1024 / (int)PAGE_SIZE / 16))
  316 #endif
  317 static void
  318 vntblinit(void *dummy __unused)
  319 {
  320         u_int i;
  321         int physvnodes, virtvnodes;
  322 
  323         /*
  324          * Desiredvnodes is a function of the physical memory size and the
  325          * kernel's heap size.  Generally speaking, it scales with the
  326          * physical memory size.  The ratio of desiredvnodes to physical pages
  327          * is one to four until desiredvnodes exceeds 98,304.  Thereafter, the
  328          * marginal ratio of desiredvnodes to physical pages is one to
  329          * sixteen.  However, desiredvnodes is limited by the kernel's heap
  330          * size.  The memory required by desiredvnodes vnodes and vm objects
  331          * may not exceed one seventh of the kernel's heap size.
  332          */
  333         physvnodes = maxproc + cnt.v_page_count / 16 + 3 * min(98304 * 4,
  334             cnt.v_page_count) / 16;
  335         virtvnodes = vm_kmem_size / (7 * (sizeof(struct vm_object) +
  336             sizeof(struct vnode)));
  337         desiredvnodes = min(physvnodes, virtvnodes);
  338         if (desiredvnodes > MAXVNODES_MAX) {
  339                 if (bootverbose)
  340                         printf("Reducing kern.maxvnodes %d -> %d\n",
  341                             desiredvnodes, MAXVNODES_MAX);
  342                 desiredvnodes = MAXVNODES_MAX;
  343         }
  344         wantfreevnodes = desiredvnodes / 4;
  345         mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
  346         TAILQ_INIT(&vnode_free_list);
  347         mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
  348         vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
  349             NULL, NULL, UMA_ALIGN_PTR, 0);
  350         vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
  351             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  352         /*
  353          * Preallocate enough nodes to support one-per buf so that
  354          * we can not fail an insert.  reassignbuf() callers can not
  355          * tolerate the insertion failure.
  356          */
  357         buf_trie_zone = uma_zcreate("BUF TRIE", pctrie_node_size(),
  358             NULL, NULL, pctrie_zone_init, NULL, UMA_ALIGN_PTR, 
  359             UMA_ZONE_NOFREE | UMA_ZONE_VM);
  360         uma_prealloc(buf_trie_zone, nbuf);
  361         /*
  362          * Initialize the filesystem syncer.
  363          */
  364         syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE,
  365             &syncer_mask);
  366         syncer_maxdelay = syncer_mask + 1;
  367         mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
  368         cv_init(&sync_wakeup, "syncer");
  369         for (i = 1; i <= sizeof(struct vnode); i <<= 1)
  370                 vnsz2log++;
  371         vnsz2log--;
  372 }
  373 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL);
  374 
  375 
  376 /*
  377  * Mark a mount point as busy. Used to synchronize access and to delay
  378  * unmounting. Eventually, mountlist_mtx is not released on failure.
  379  *
  380  * vfs_busy() is a custom lock, it can block the caller.
  381  * vfs_busy() only sleeps if the unmount is active on the mount point.
  382  * For a mountpoint mp, vfs_busy-enforced lock is before lock of any
  383  * vnode belonging to mp.
  384  *
  385  * Lookup uses vfs_busy() to traverse mount points.
  386  * root fs                      var fs
  387  * / vnode lock         A       / vnode lock (/var)             D
  388  * /var vnode lock      B       /log vnode lock(/var/log)       E
  389  * vfs_busy lock        C       vfs_busy lock                   F
  390  *
  391  * Within each file system, the lock order is C->A->B and F->D->E.
  392  *
  393  * When traversing across mounts, the system follows that lock order:
  394  *
  395  *        C->A->B
  396  *              |
  397  *              +->F->D->E
  398  *
  399  * The lookup() process for namei("/var") illustrates the process:
  400  *  VOP_LOOKUP() obtains B while A is held
  401  *  vfs_busy() obtains a shared lock on F while A and B are held
  402  *  vput() releases lock on B
  403  *  vput() releases lock on A
  404  *  VFS_ROOT() obtains lock on D while shared lock on F is held
  405  *  vfs_unbusy() releases shared lock on F
  406  *  vn_lock() obtains lock on deadfs vnode vp_crossmp instead of A.
  407  *    Attempt to lock A (instead of vp_crossmp) while D is held would
  408  *    violate the global order, causing deadlocks.
  409  *
  410  * dounmount() locks B while F is drained.
  411  */
  412 int
  413 vfs_busy(struct mount *mp, int flags)
  414 {
  415 
  416         MPASS((flags & ~MBF_MASK) == 0);
  417         CTR3(KTR_VFS, "%s: mp %p with flags %d", __func__, mp, flags);
  418 
  419         MNT_ILOCK(mp);
  420         MNT_REF(mp);
  421         /*
  422          * If mount point is currenly being unmounted, sleep until the
  423          * mount point fate is decided.  If thread doing the unmounting fails,
  424          * it will clear MNTK_UNMOUNT flag before waking us up, indicating
  425          * that this mount point has survived the unmount attempt and vfs_busy
  426          * should retry.  Otherwise the unmounter thread will set MNTK_REFEXPIRE
  427          * flag in addition to MNTK_UNMOUNT, indicating that mount point is
  428          * about to be really destroyed.  vfs_busy needs to release its
  429          * reference on the mount point in this case and return with ENOENT,
  430          * telling the caller that mount mount it tried to busy is no longer
  431          * valid.
  432          */
  433         while (mp->mnt_kern_flag & MNTK_UNMOUNT) {
  434                 if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) {
  435                         MNT_REL(mp);
  436                         MNT_IUNLOCK(mp);
  437                         CTR1(KTR_VFS, "%s: failed busying before sleeping",
  438                             __func__);
  439                         return (ENOENT);
  440                 }
  441                 if (flags & MBF_MNTLSTLOCK)
  442                         mtx_unlock(&mountlist_mtx);
  443                 mp->mnt_kern_flag |= MNTK_MWAIT;
  444                 msleep(mp, MNT_MTX(mp), PVFS | PDROP, "vfs_busy", 0);
  445                 if (flags & MBF_MNTLSTLOCK)
  446                         mtx_lock(&mountlist_mtx);
  447                 MNT_ILOCK(mp);
  448         }
  449         if (flags & MBF_MNTLSTLOCK)
  450                 mtx_unlock(&mountlist_mtx);
  451         mp->mnt_lockref++;
  452         MNT_IUNLOCK(mp);
  453         return (0);
  454 }
  455 
  456 /*
  457  * Free a busy filesystem.
  458  */
  459 void
  460 vfs_unbusy(struct mount *mp)
  461 {
  462 
  463         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  464         MNT_ILOCK(mp);
  465         MNT_REL(mp);
  466         KASSERT(mp->mnt_lockref > 0, ("negative mnt_lockref"));
  467         mp->mnt_lockref--;
  468         if (mp->mnt_lockref == 0 && (mp->mnt_kern_flag & MNTK_DRAINING) != 0) {
  469                 MPASS(mp->mnt_kern_flag & MNTK_UNMOUNT);
  470                 CTR1(KTR_VFS, "%s: waking up waiters", __func__);
  471                 mp->mnt_kern_flag &= ~MNTK_DRAINING;
  472                 wakeup(&mp->mnt_lockref);
  473         }
  474         MNT_IUNLOCK(mp);
  475 }
  476 
  477 /*
  478  * Lookup a mount point by filesystem identifier.
  479  */
  480 struct mount *
  481 vfs_getvfs(fsid_t *fsid)
  482 {
  483         struct mount *mp;
  484 
  485         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  486         mtx_lock(&mountlist_mtx);
  487         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  488                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  489                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  490                         vfs_ref(mp);
  491                         mtx_unlock(&mountlist_mtx);
  492                         return (mp);
  493                 }
  494         }
  495         mtx_unlock(&mountlist_mtx);
  496         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  497         return ((struct mount *) 0);
  498 }
  499 
  500 /*
  501  * Lookup a mount point by filesystem identifier, busying it before
  502  * returning.
  503  */
  504 struct mount *
  505 vfs_busyfs(fsid_t *fsid)
  506 {
  507         struct mount *mp;
  508         int error;
  509 
  510         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  511         mtx_lock(&mountlist_mtx);
  512         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  513                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  514                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  515                         error = vfs_busy(mp, MBF_MNTLSTLOCK);
  516                         if (error) {
  517                                 mtx_unlock(&mountlist_mtx);
  518                                 return (NULL);
  519                         }
  520                         return (mp);
  521                 }
  522         }
  523         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  524         mtx_unlock(&mountlist_mtx);
  525         return ((struct mount *) 0);
  526 }
  527 
  528 /*
  529  * Check if a user can access privileged mount options.
  530  */
  531 int
  532 vfs_suser(struct mount *mp, struct thread *td)
  533 {
  534         int error;
  535 
  536         /*
  537          * If the thread is jailed, but this is not a jail-friendly file
  538          * system, deny immediately.
  539          */
  540         if (!(mp->mnt_vfc->vfc_flags & VFCF_JAIL) && jailed(td->td_ucred))
  541                 return (EPERM);
  542 
  543         /*
  544          * If the file system was mounted outside the jail of the calling
  545          * thread, deny immediately.
  546          */
  547         if (prison_check(td->td_ucred, mp->mnt_cred) != 0)
  548                 return (EPERM);
  549 
  550         /*
  551          * If file system supports delegated administration, we don't check
  552          * for the PRIV_VFS_MOUNT_OWNER privilege - it will be better verified
  553          * by the file system itself.
  554          * If this is not the user that did original mount, we check for
  555          * the PRIV_VFS_MOUNT_OWNER privilege.
  556          */
  557         if (!(mp->mnt_vfc->vfc_flags & VFCF_DELEGADMIN) &&
  558             mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
  559                 if ((error = priv_check(td, PRIV_VFS_MOUNT_OWNER)) != 0)
  560                         return (error);
  561         }
  562         return (0);
  563 }
  564 
  565 /*
  566  * Get a new unique fsid.  Try to make its val[0] unique, since this value
  567  * will be used to create fake device numbers for stat().  Also try (but
  568  * not so hard) make its val[0] unique mod 2^16, since some emulators only
  569  * support 16-bit device numbers.  We end up with unique val[0]'s for the
  570  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
  571  *
  572  * Keep in mind that several mounts may be running in parallel.  Starting
  573  * the search one past where the previous search terminated is both a
  574  * micro-optimization and a defense against returning the same fsid to
  575  * different mounts.
  576  */
  577 void
  578 vfs_getnewfsid(struct mount *mp)
  579 {
  580         static uint16_t mntid_base;
  581         struct mount *nmp;
  582         fsid_t tfsid;
  583         int mtype;
  584 
  585         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  586         mtx_lock(&mntid_mtx);
  587         mtype = mp->mnt_vfc->vfc_typenum;
  588         tfsid.val[1] = mtype;
  589         mtype = (mtype & 0xFF) << 24;
  590         for (;;) {
  591                 tfsid.val[0] = makedev(255,
  592                     mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
  593                 mntid_base++;
  594                 if ((nmp = vfs_getvfs(&tfsid)) == NULL)
  595                         break;
  596                 vfs_rel(nmp);
  597         }
  598         mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
  599         mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
  600         mtx_unlock(&mntid_mtx);
  601 }
  602 
  603 /*
  604  * Knob to control the precision of file timestamps:
  605  *
  606  *   0 = seconds only; nanoseconds zeroed.
  607  *   1 = seconds and nanoseconds, accurate within 1/HZ.
  608  *   2 = seconds and nanoseconds, truncated to microseconds.
  609  * >=3 = seconds and nanoseconds, maximum precision.
  610  */
  611 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
  612 
  613 static int timestamp_precision = TSP_SEC;
  614 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
  615     &timestamp_precision, 0, "File timestamp precision (0: seconds, "
  616     "1: sec + ns accurate to 1/HZ, 2: sec + ns truncated to ms, "
  617     "3+: sec + ns (max. precision))");
  618 
  619 /*
  620  * Get a current timestamp.
  621  */
  622 void
  623 vfs_timestamp(struct timespec *tsp)
  624 {
  625         struct timeval tv;
  626 
  627         switch (timestamp_precision) {
  628         case TSP_SEC:
  629                 tsp->tv_sec = time_second;
  630                 tsp->tv_nsec = 0;
  631                 break;
  632         case TSP_HZ:
  633                 getnanotime(tsp);
  634                 break;
  635         case TSP_USEC:
  636                 microtime(&tv);
  637                 TIMEVAL_TO_TIMESPEC(&tv, tsp);
  638                 break;
  639         case TSP_NSEC:
  640         default:
  641                 nanotime(tsp);
  642                 break;
  643         }
  644 }
  645 
  646 /*
  647  * Set vnode attributes to VNOVAL
  648  */
  649 void
  650 vattr_null(struct vattr *vap)
  651 {
  652 
  653         vap->va_type = VNON;
  654         vap->va_size = VNOVAL;
  655         vap->va_bytes = VNOVAL;
  656         vap->va_mode = VNOVAL;
  657         vap->va_nlink = VNOVAL;
  658         vap->va_uid = VNOVAL;
  659         vap->va_gid = VNOVAL;
  660         vap->va_fsid = VNOVAL;
  661         vap->va_fileid = VNOVAL;
  662         vap->va_blocksize = VNOVAL;
  663         vap->va_rdev = VNOVAL;
  664         vap->va_atime.tv_sec = VNOVAL;
  665         vap->va_atime.tv_nsec = VNOVAL;
  666         vap->va_mtime.tv_sec = VNOVAL;
  667         vap->va_mtime.tv_nsec = VNOVAL;
  668         vap->va_ctime.tv_sec = VNOVAL;
  669         vap->va_ctime.tv_nsec = VNOVAL;
  670         vap->va_birthtime.tv_sec = VNOVAL;
  671         vap->va_birthtime.tv_nsec = VNOVAL;
  672         vap->va_flags = VNOVAL;
  673         vap->va_gen = VNOVAL;
  674         vap->va_vaflags = 0;
  675 }
  676 
  677 /*
  678  * This routine is called when we have too many vnodes.  It attempts
  679  * to free <count> vnodes and will potentially free vnodes that still
  680  * have VM backing store (VM backing store is typically the cause
  681  * of a vnode blowout so we want to do this).  Therefore, this operation
  682  * is not considered cheap.
  683  *
  684  * A number of conditions may prevent a vnode from being reclaimed.
  685  * the buffer cache may have references on the vnode, a directory
  686  * vnode may still have references due to the namei cache representing
  687  * underlying files, or the vnode may be in active use.   It is not
  688  * desireable to reuse such vnodes.  These conditions may cause the
  689  * number of vnodes to reach some minimum value regardless of what
  690  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
  691  */
  692 static int
  693 vlrureclaim(struct mount *mp)
  694 {
  695         struct vnode *vp;
  696         int done;
  697         int trigger;
  698         int usevnodes;
  699         int count;
  700 
  701         /*
  702          * Calculate the trigger point, don't allow user
  703          * screwups to blow us up.   This prevents us from
  704          * recycling vnodes with lots of resident pages.  We
  705          * aren't trying to free memory, we are trying to
  706          * free vnodes.
  707          */
  708         usevnodes = desiredvnodes;
  709         if (usevnodes <= 0)
  710                 usevnodes = 1;
  711         trigger = cnt.v_page_count * 2 / usevnodes;
  712         done = 0;
  713         vn_start_write(NULL, &mp, V_WAIT);
  714         MNT_ILOCK(mp);
  715         count = mp->mnt_nvnodelistsize / 10 + 1;
  716         while (count != 0) {
  717                 vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
  718                 while (vp != NULL && vp->v_type == VMARKER)
  719                         vp = TAILQ_NEXT(vp, v_nmntvnodes);
  720                 if (vp == NULL)
  721                         break;
  722                 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  723                 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  724                 --count;
  725                 if (!VI_TRYLOCK(vp))
  726                         goto next_iter;
  727                 /*
  728                  * If it's been deconstructed already, it's still
  729                  * referenced, or it exceeds the trigger, skip it.
  730                  */
  731                 if (vp->v_usecount ||
  732                     (!vlru_allow_cache_src &&
  733                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  734                     (vp->v_iflag & VI_DOOMED) != 0 || (vp->v_object != NULL &&
  735                     vp->v_object->resident_page_count > trigger)) {
  736                         VI_UNLOCK(vp);
  737                         goto next_iter;
  738                 }
  739                 MNT_IUNLOCK(mp);
  740                 vholdl(vp);
  741                 if (VOP_LOCK(vp, LK_INTERLOCK|LK_EXCLUSIVE|LK_NOWAIT)) {
  742                         vdrop(vp);
  743                         goto next_iter_mntunlocked;
  744                 }
  745                 VI_LOCK(vp);
  746                 /*
  747                  * v_usecount may have been bumped after VOP_LOCK() dropped
  748                  * the vnode interlock and before it was locked again.
  749                  *
  750                  * It is not necessary to recheck VI_DOOMED because it can
  751                  * only be set by another thread that holds both the vnode
  752                  * lock and vnode interlock.  If another thread has the
  753                  * vnode lock before we get to VOP_LOCK() and obtains the
  754                  * vnode interlock after VOP_LOCK() drops the vnode
  755                  * interlock, the other thread will be unable to drop the
  756                  * vnode lock before our VOP_LOCK() call fails.
  757                  */
  758                 if (vp->v_usecount ||
  759                     (!vlru_allow_cache_src &&
  760                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  761                     (vp->v_object != NULL &&
  762                     vp->v_object->resident_page_count > trigger)) {
  763                         VOP_UNLOCK(vp, LK_INTERLOCK);
  764                         vdrop(vp);
  765                         goto next_iter_mntunlocked;
  766                 }
  767                 KASSERT((vp->v_iflag & VI_DOOMED) == 0,
  768                     ("VI_DOOMED unexpectedly detected in vlrureclaim()"));
  769                 vgonel(vp);
  770                 VOP_UNLOCK(vp, 0);
  771                 vdropl(vp);
  772                 done++;
  773 next_iter_mntunlocked:
  774                 if (!should_yield())
  775                         goto relock_mnt;
  776                 goto yield;
  777 next_iter:
  778                 if (!should_yield())
  779                         continue;
  780                 MNT_IUNLOCK(mp);
  781 yield:
  782                 kern_yield(PRI_USER);
  783 relock_mnt:
  784                 MNT_ILOCK(mp);
  785         }
  786         MNT_IUNLOCK(mp);
  787         vn_finished_write(mp);
  788         return done;
  789 }
  790 
  791 /*
  792  * Attempt to keep the free list at wantfreevnodes length.
  793  */
  794 static void
  795 vnlru_free(int count)
  796 {
  797         struct vnode *vp;
  798 
  799         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
  800         for (; count > 0; count--) {
  801                 vp = TAILQ_FIRST(&vnode_free_list);
  802                 /*
  803                  * The list can be modified while the free_list_mtx
  804                  * has been dropped and vp could be NULL here.
  805                  */
  806                 if (!vp)
  807                         break;
  808                 VNASSERT(vp->v_op != NULL, vp,
  809                     ("vnlru_free: vnode already reclaimed."));
  810                 KASSERT((vp->v_iflag & VI_FREE) != 0,
  811                     ("Removing vnode not on freelist"));
  812                 KASSERT((vp->v_iflag & VI_ACTIVE) == 0,
  813                     ("Mangling active vnode"));
  814                 TAILQ_REMOVE(&vnode_free_list, vp, v_actfreelist);
  815                 /*
  816                  * Don't recycle if we can't get the interlock.
  817                  */
  818                 if (!VI_TRYLOCK(vp)) {
  819                         TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_actfreelist);
  820                         continue;
  821                 }
  822                 VNASSERT(VCANRECYCLE(vp), vp,
  823                     ("vp inconsistent on freelist"));
  824                 freevnodes--;
  825                 vp->v_iflag &= ~VI_FREE;
  826                 vholdl(vp);
  827                 mtx_unlock(&vnode_free_list_mtx);
  828                 VI_UNLOCK(vp);
  829                 vtryrecycle(vp);
  830                 /*
  831                  * If the recycled succeeded this vdrop will actually free
  832                  * the vnode.  If not it will simply place it back on
  833                  * the free list.
  834                  */
  835                 vdrop(vp);
  836                 mtx_lock(&vnode_free_list_mtx);
  837         }
  838 }
  839 /*
  840  * Attempt to recycle vnodes in a context that is always safe to block.
  841  * Calling vlrurecycle() from the bowels of filesystem code has some
  842  * interesting deadlock problems.
  843  */
  844 static struct proc *vnlruproc;
  845 static int vnlruproc_sig;
  846 
  847 static void
  848 vnlru_proc(void)
  849 {
  850         struct mount *mp, *nmp;
  851         int done;
  852         struct proc *p = vnlruproc;
  853 
  854         EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
  855             SHUTDOWN_PRI_FIRST);
  856 
  857         for (;;) {
  858                 kproc_suspend_check(p);
  859                 mtx_lock(&vnode_free_list_mtx);
  860                 if (freevnodes > wantfreevnodes)
  861                         vnlru_free(freevnodes - wantfreevnodes);
  862                 if (numvnodes <= desiredvnodes * 9 / 10) {
  863                         vnlruproc_sig = 0;
  864                         wakeup(&vnlruproc_sig);
  865                         msleep(vnlruproc, &vnode_free_list_mtx,
  866                             PVFS|PDROP, "vlruwt", hz);
  867                         continue;
  868                 }
  869                 mtx_unlock(&vnode_free_list_mtx);
  870                 done = 0;
  871                 mtx_lock(&mountlist_mtx);
  872                 for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
  873                         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
  874                                 nmp = TAILQ_NEXT(mp, mnt_list);
  875                                 continue;
  876                         }
  877                         done += vlrureclaim(mp);
  878                         mtx_lock(&mountlist_mtx);
  879                         nmp = TAILQ_NEXT(mp, mnt_list);
  880                         vfs_unbusy(mp);
  881                 }
  882                 mtx_unlock(&mountlist_mtx);
  883                 if (done == 0) {
  884 #if 0
  885                         /* These messages are temporary debugging aids */
  886                         if (vnlru_nowhere < 5)
  887                                 printf("vnlru process getting nowhere..\n");
  888                         else if (vnlru_nowhere == 5)
  889                                 printf("vnlru process messages stopped.\n");
  890 #endif
  891                         vnlru_nowhere++;
  892                         tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
  893                 } else
  894                         kern_yield(PRI_USER);
  895         }
  896 }
  897 
  898 static struct kproc_desc vnlru_kp = {
  899         "vnlru",
  900         vnlru_proc,
  901         &vnlruproc
  902 };
  903 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start,
  904     &vnlru_kp);
  905  
  906 /*
  907  * Routines having to do with the management of the vnode table.
  908  */
  909 
  910 /*
  911  * Try to recycle a freed vnode.  We abort if anyone picks up a reference
  912  * before we actually vgone().  This function must be called with the vnode
  913  * held to prevent the vnode from being returned to the free list midway
  914  * through vgone().
  915  */
  916 static int
  917 vtryrecycle(struct vnode *vp)
  918 {
  919         struct mount *vnmp;
  920 
  921         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  922         VNASSERT(vp->v_holdcnt, vp,
  923             ("vtryrecycle: Recycling vp %p without a reference.", vp));
  924         /*
  925          * This vnode may found and locked via some other list, if so we
  926          * can't recycle it yet.
  927          */
  928         if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
  929                 CTR2(KTR_VFS,
  930                     "%s: impossible to recycle, vp %p lock is already held",
  931                     __func__, vp);
  932                 return (EWOULDBLOCK);
  933         }
  934         /*
  935          * Don't recycle if its filesystem is being suspended.
  936          */
  937         if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
  938                 VOP_UNLOCK(vp, 0);
  939                 CTR2(KTR_VFS,
  940                     "%s: impossible to recycle, cannot start the write for %p",
  941                     __func__, vp);
  942                 return (EBUSY);
  943         }
  944         /*
  945          * If we got this far, we need to acquire the interlock and see if
  946          * anyone picked up this vnode from another list.  If not, we will
  947          * mark it with DOOMED via vgonel() so that anyone who does find it
  948          * will skip over it.
  949          */
  950         VI_LOCK(vp);
  951         if (vp->v_usecount) {
  952                 VOP_UNLOCK(vp, LK_INTERLOCK);
  953                 vn_finished_write(vnmp);
  954                 CTR2(KTR_VFS,
  955                     "%s: impossible to recycle, %p is already referenced",
  956                     __func__, vp);
  957                 return (EBUSY);
  958         }
  959         if ((vp->v_iflag & VI_DOOMED) == 0)
  960                 vgonel(vp);
  961         VOP_UNLOCK(vp, LK_INTERLOCK);
  962         vn_finished_write(vnmp);
  963         return (0);
  964 }
  965 
  966 /*
  967  * Wait for available vnodes.
  968  */
  969 static int
  970 getnewvnode_wait(int suspended)
  971 {
  972 
  973         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
  974         if (numvnodes > desiredvnodes) {
  975                 if (suspended) {
  976                         /*
  977                          * File system is beeing suspended, we cannot risk a
  978                          * deadlock here, so allocate new vnode anyway.
  979                          */
  980                         if (freevnodes > wantfreevnodes)
  981                                 vnlru_free(freevnodes - wantfreevnodes);
  982                         return (0);
  983                 }
  984                 if (vnlruproc_sig == 0) {
  985                         vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
  986                         wakeup(vnlruproc);
  987                 }
  988                 msleep(&vnlruproc_sig, &vnode_free_list_mtx, PVFS,
  989                     "vlruwk", hz);
  990         }
  991         return (numvnodes > desiredvnodes ? ENFILE : 0);
  992 }
  993 
  994 void
  995 getnewvnode_reserve(u_int count)
  996 {
  997         struct thread *td;
  998 
  999         td = curthread;
 1000         mtx_lock(&vnode_free_list_mtx);
 1001         while (count > 0) {
 1002                 if (getnewvnode_wait(0) == 0) {
 1003                         count--;
 1004                         td->td_vp_reserv++;
 1005                         numvnodes++;
 1006                 }
 1007         }
 1008         mtx_unlock(&vnode_free_list_mtx);
 1009 }
 1010 
 1011 void
 1012 getnewvnode_drop_reserve(void)
 1013 {
 1014         struct thread *td;
 1015 
 1016         td = curthread;
 1017         mtx_lock(&vnode_free_list_mtx);
 1018         KASSERT(numvnodes >= td->td_vp_reserv, ("reserve too large"));
 1019         numvnodes -= td->td_vp_reserv;
 1020         mtx_unlock(&vnode_free_list_mtx);
 1021         td->td_vp_reserv = 0;
 1022 }
 1023 
 1024 /*
 1025  * Return the next vnode from the free list.
 1026  */
 1027 int
 1028 getnewvnode(const char *tag, struct mount *mp, struct vop_vector *vops,
 1029     struct vnode **vpp)
 1030 {
 1031         struct vnode *vp;
 1032         struct bufobj *bo;
 1033         struct thread *td;
 1034         int error;
 1035 
 1036         CTR3(KTR_VFS, "%s: mp %p with tag %s", __func__, mp, tag);
 1037         vp = NULL;
 1038         td = curthread;
 1039         if (td->td_vp_reserv > 0) {
 1040                 td->td_vp_reserv -= 1;
 1041                 goto alloc;
 1042         }
 1043         mtx_lock(&vnode_free_list_mtx);
 1044         /*
 1045          * Lend our context to reclaim vnodes if they've exceeded the max.
 1046          */
 1047         if (freevnodes > wantfreevnodes)
 1048                 vnlru_free(1);
 1049         error = getnewvnode_wait(mp != NULL && (mp->mnt_kern_flag &
 1050             MNTK_SUSPEND));
 1051 #if 0   /* XXX Not all VFS_VGET/ffs_vget callers check returns. */
 1052         if (error != 0) {
 1053                 mtx_unlock(&vnode_free_list_mtx);
 1054                 return (error);
 1055         }
 1056 #endif
 1057         numvnodes++;
 1058         mtx_unlock(&vnode_free_list_mtx);
 1059 alloc:
 1060         vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
 1061         /*
 1062          * Setup locks.
 1063          */
 1064         vp->v_vnlock = &vp->v_lock;
 1065         mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
 1066         /*
 1067          * By default, don't allow shared locks unless filesystems
 1068          * opt-in.
 1069          */
 1070         lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOSHARE | LK_IS_VNODE);
 1071         /*
 1072          * Initialize bufobj.
 1073          */
 1074         bo = &vp->v_bufobj;
 1075         bo->__bo_vnode = vp;
 1076         rw_init(BO_LOCKPTR(bo), "bufobj interlock");
 1077         bo->bo_ops = &buf_ops_bio;
 1078         bo->bo_private = vp;
 1079         TAILQ_INIT(&bo->bo_clean.bv_hd);
 1080         TAILQ_INIT(&bo->bo_dirty.bv_hd);
 1081         /*
 1082          * Initialize namecache.
 1083          */
 1084         LIST_INIT(&vp->v_cache_src);
 1085         TAILQ_INIT(&vp->v_cache_dst);
 1086         /*
 1087          * Finalize various vnode identity bits.
 1088          */
 1089         vp->v_type = VNON;
 1090         vp->v_tag = tag;
 1091         vp->v_op = vops;
 1092         v_incr_usecount(vp);
 1093         vp->v_data = NULL;
 1094 #ifdef MAC
 1095         mac_vnode_init(vp);
 1096         if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
 1097                 mac_vnode_associate_singlelabel(mp, vp);
 1098         else if (mp == NULL && vops != &dead_vnodeops)
 1099                 printf("NULL mp in getnewvnode()\n");
 1100 #endif
 1101         if (mp != NULL) {
 1102                 bo->bo_bsize = mp->mnt_stat.f_iosize;
 1103                 if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
 1104                         vp->v_vflag |= VV_NOKNOTE;
 1105         }
 1106         rangelock_init(&vp->v_rl);
 1107 
 1108         /*
 1109          * For the filesystems which do not use vfs_hash_insert(),
 1110          * still initialize v_hash to have vfs_hash_index() useful.
 1111          * E.g., nullfs uses vfs_hash_index() on the lower vnode for
 1112          * its own hashing.
 1113          */
 1114         vp->v_hash = (uintptr_t)vp >> vnsz2log;
 1115 
 1116         *vpp = vp;
 1117         return (0);
 1118 }
 1119 
 1120 /*
 1121  * Delete from old mount point vnode list, if on one.
 1122  */
 1123 static void
 1124 delmntque(struct vnode *vp)
 1125 {
 1126         struct mount *mp;
 1127         int active;
 1128 
 1129         mp = vp->v_mount;
 1130         if (mp == NULL)
 1131                 return;
 1132         MNT_ILOCK(mp);
 1133         VI_LOCK(vp);
 1134         KASSERT(mp->mnt_activevnodelistsize <= mp->mnt_nvnodelistsize,
 1135             ("Active vnode list size %d > Vnode list size %d",
 1136              mp->mnt_activevnodelistsize, mp->mnt_nvnodelistsize));
 1137         active = vp->v_iflag & VI_ACTIVE;
 1138         vp->v_iflag &= ~VI_ACTIVE;
 1139         if (active) {
 1140                 mtx_lock(&vnode_free_list_mtx);
 1141                 TAILQ_REMOVE(&mp->mnt_activevnodelist, vp, v_actfreelist);
 1142                 mp->mnt_activevnodelistsize--;
 1143                 mtx_unlock(&vnode_free_list_mtx);
 1144         }
 1145         vp->v_mount = NULL;
 1146         VI_UNLOCK(vp);
 1147         VNASSERT(mp->mnt_nvnodelistsize > 0, vp,
 1148                 ("bad mount point vnode list size"));
 1149         TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1150         mp->mnt_nvnodelistsize--;
 1151         MNT_REL(mp);
 1152         MNT_IUNLOCK(mp);
 1153 }
 1154 
 1155 static void
 1156 insmntque_stddtr(struct vnode *vp, void *dtr_arg)
 1157 {
 1158 
 1159         vp->v_data = NULL;
 1160         vp->v_op = &dead_vnodeops;
 1161         vgone(vp);
 1162         vput(vp);
 1163 }
 1164 
 1165 /*
 1166  * Insert into list of vnodes for the new mount point, if available.
 1167  */
 1168 int
 1169 insmntque1(struct vnode *vp, struct mount *mp,
 1170         void (*dtr)(struct vnode *, void *), void *dtr_arg)
 1171 {
 1172 
 1173         KASSERT(vp->v_mount == NULL,
 1174                 ("insmntque: vnode already on per mount vnode list"));
 1175         VNASSERT(mp != NULL, vp, ("Don't call insmntque(foo, NULL)"));
 1176         ASSERT_VOP_ELOCKED(vp, "insmntque: non-locked vp");
 1177 
 1178         /*
 1179          * We acquire the vnode interlock early to ensure that the
 1180          * vnode cannot be recycled by another process releasing a
 1181          * holdcnt on it before we get it on both the vnode list
 1182          * and the active vnode list. The mount mutex protects only
 1183          * manipulation of the vnode list and the vnode freelist
 1184          * mutex protects only manipulation of the active vnode list.
 1185          * Hence the need to hold the vnode interlock throughout.
 1186          */
 1187         MNT_ILOCK(mp);
 1188         VI_LOCK(vp);
 1189         if (((mp->mnt_kern_flag & MNTK_NOINSMNTQ) != 0 &&
 1190             ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0 ||
 1191             mp->mnt_nvnodelistsize == 0)) &&
 1192             (vp->v_vflag & VV_FORCEINSMQ) == 0) {
 1193                 VI_UNLOCK(vp);
 1194                 MNT_IUNLOCK(mp);
 1195                 if (dtr != NULL)
 1196                         dtr(vp, dtr_arg);
 1197                 return (EBUSY);
 1198         }
 1199         vp->v_mount = mp;
 1200         MNT_REF(mp);
 1201         TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1202         VNASSERT(mp->mnt_nvnodelistsize >= 0, vp,
 1203                 ("neg mount point vnode list size"));
 1204         mp->mnt_nvnodelistsize++;
 1205         KASSERT((vp->v_iflag & VI_ACTIVE) == 0,
 1206             ("Activating already active vnode"));
 1207         vp->v_iflag |= VI_ACTIVE;
 1208         mtx_lock(&vnode_free_list_mtx);
 1209         TAILQ_INSERT_HEAD(&mp->mnt_activevnodelist, vp, v_actfreelist);
 1210         mp->mnt_activevnodelistsize++;
 1211         mtx_unlock(&vnode_free_list_mtx);
 1212         VI_UNLOCK(vp);
 1213         MNT_IUNLOCK(mp);
 1214         return (0);
 1215 }
 1216 
 1217 int
 1218 insmntque(struct vnode *vp, struct mount *mp)
 1219 {
 1220 
 1221         return (insmntque1(vp, mp, insmntque_stddtr, NULL));
 1222 }
 1223 
 1224 /*
 1225  * Flush out and invalidate all buffers associated with a bufobj
 1226  * Called with the underlying object locked.
 1227  */
 1228 int
 1229 bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo)
 1230 {
 1231         int error;
 1232 
 1233         BO_LOCK(bo);
 1234         if (flags & V_SAVE) {
 1235                 error = bufobj_wwait(bo, slpflag, slptimeo);
 1236                 if (error) {
 1237                         BO_UNLOCK(bo);
 1238                         return (error);
 1239                 }
 1240                 if (bo->bo_dirty.bv_cnt > 0) {
 1241                         BO_UNLOCK(bo);
 1242                         if ((error = BO_SYNC(bo, MNT_WAIT)) != 0)
 1243                                 return (error);
 1244                         /*
 1245                          * XXX We could save a lock/unlock if this was only
 1246                          * enabled under INVARIANTS
 1247                          */
 1248                         BO_LOCK(bo);
 1249                         if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
 1250                                 panic("vinvalbuf: dirty bufs");
 1251                 }
 1252         }
 1253         /*
 1254          * If you alter this loop please notice that interlock is dropped and
 1255          * reacquired in flushbuflist.  Special care is needed to ensure that
 1256          * no race conditions occur from this.
 1257          */
 1258         do {
 1259                 error = flushbuflist(&bo->bo_clean,
 1260                     flags, bo, slpflag, slptimeo);
 1261                 if (error == 0 && !(flags & V_CLEANONLY))
 1262                         error = flushbuflist(&bo->bo_dirty,
 1263                             flags, bo, slpflag, slptimeo);
 1264                 if (error != 0 && error != EAGAIN) {
 1265                         BO_UNLOCK(bo);
 1266                         return (error);
 1267                 }
 1268         } while (error != 0);
 1269 
 1270         /*
 1271          * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
 1272          * have write I/O in-progress but if there is a VM object then the
 1273          * VM object can also have read-I/O in-progress.
 1274          */
 1275         do {
 1276                 bufobj_wwait(bo, 0, 0);
 1277                 BO_UNLOCK(bo);
 1278                 if (bo->bo_object != NULL) {
 1279                         VM_OBJECT_WLOCK(bo->bo_object);
 1280                         vm_object_pip_wait(bo->bo_object, "bovlbx");
 1281                         VM_OBJECT_WUNLOCK(bo->bo_object);
 1282                 }
 1283                 BO_LOCK(bo);
 1284         } while (bo->bo_numoutput > 0);
 1285         BO_UNLOCK(bo);
 1286 
 1287         /*
 1288          * Destroy the copy in the VM cache, too.
 1289          */
 1290         if (bo->bo_object != NULL &&
 1291             (flags & (V_ALT | V_NORMAL | V_CLEANONLY)) == 0) {
 1292                 VM_OBJECT_WLOCK(bo->bo_object);
 1293                 vm_object_page_remove(bo->bo_object, 0, 0, (flags & V_SAVE) ?
 1294                     OBJPR_CLEANONLY : 0);
 1295                 VM_OBJECT_WUNLOCK(bo->bo_object);
 1296         }
 1297 
 1298 #ifdef INVARIANTS
 1299         BO_LOCK(bo);
 1300         if ((flags & (V_ALT | V_NORMAL | V_CLEANONLY)) == 0 &&
 1301             (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
 1302                 panic("vinvalbuf: flush failed");
 1303         BO_UNLOCK(bo);
 1304 #endif
 1305         return (0);
 1306 }
 1307 
 1308 /*
 1309  * Flush out and invalidate all buffers associated with a vnode.
 1310  * Called with the underlying object locked.
 1311  */
 1312 int
 1313 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
 1314 {
 1315 
 1316         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 1317         ASSERT_VOP_LOCKED(vp, "vinvalbuf");
 1318         if (vp->v_object != NULL && vp->v_object->handle != vp)
 1319                 return (0);
 1320         return (bufobj_invalbuf(&vp->v_bufobj, flags, slpflag, slptimeo));
 1321 }
 1322 
 1323 /*
 1324  * Flush out buffers on the specified list.
 1325  *
 1326  */
 1327 static int
 1328 flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo, int slpflag,
 1329     int slptimeo)
 1330 {
 1331         struct buf *bp, *nbp;
 1332         int retval, error;
 1333         daddr_t lblkno;
 1334         b_xflags_t xflags;
 1335 
 1336         ASSERT_BO_WLOCKED(bo);
 1337 
 1338         retval = 0;
 1339         TAILQ_FOREACH_SAFE(bp, &bufv->bv_hd, b_bobufs, nbp) {
 1340                 if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
 1341                     ((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
 1342                         continue;
 1343                 }
 1344                 lblkno = 0;
 1345                 xflags = 0;
 1346                 if (nbp != NULL) {
 1347                         lblkno = nbp->b_lblkno;
 1348                         xflags = nbp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN);
 1349                 }
 1350                 retval = EAGAIN;
 1351                 error = BUF_TIMELOCK(bp,
 1352                     LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, BO_LOCKPTR(bo),
 1353                     "flushbuf", slpflag, slptimeo);
 1354                 if (error) {
 1355                         BO_LOCK(bo);
 1356                         return (error != ENOLCK ? error : EAGAIN);
 1357                 }
 1358                 KASSERT(bp->b_bufobj == bo,
 1359                     ("bp %p wrong b_bufobj %p should be %p",
 1360                     bp, bp->b_bufobj, bo));
 1361                 if (bp->b_bufobj != bo) {       /* XXX: necessary ? */
 1362                         BUF_UNLOCK(bp);
 1363                         BO_LOCK(bo);
 1364                         return (EAGAIN);
 1365                 }
 1366                 /*
 1367                  * XXX Since there are no node locks for NFS, I
 1368                  * believe there is a slight chance that a delayed
 1369                  * write will occur while sleeping just above, so
 1370                  * check for it.
 1371                  */
 1372                 if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
 1373                     (flags & V_SAVE)) {
 1374                         bremfree(bp);
 1375                         bp->b_flags |= B_ASYNC;
 1376                         bwrite(bp);
 1377                         BO_LOCK(bo);
 1378                         return (EAGAIN);        /* XXX: why not loop ? */
 1379                 }
 1380                 bremfree(bp);
 1381                 bp->b_flags |= (B_INVAL | B_RELBUF);
 1382                 bp->b_flags &= ~B_ASYNC;
 1383                 brelse(bp);
 1384                 BO_LOCK(bo);
 1385                 if (nbp != NULL &&
 1386                     (nbp->b_bufobj != bo ||
 1387                      nbp->b_lblkno != lblkno ||
 1388                      (nbp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) != xflags))
 1389                         break;                  /* nbp invalid */
 1390         }
 1391         return (retval);
 1392 }
 1393 
 1394 /*
 1395  * Truncate a file's buffer and pages to a specified length.  This
 1396  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
 1397  * sync activity.
 1398  */
 1399 int
 1400 vtruncbuf(struct vnode *vp, struct ucred *cred, off_t length, int blksize)
 1401 {
 1402         struct buf *bp, *nbp;
 1403         int anyfreed;
 1404         int trunclbn;
 1405         struct bufobj *bo;
 1406 
 1407         CTR5(KTR_VFS, "%s: vp %p with cred %p and block %d:%ju", __func__,
 1408             vp, cred, blksize, (uintmax_t)length);
 1409 
 1410         /*
 1411          * Round up to the *next* lbn.
 1412          */
 1413         trunclbn = (length + blksize - 1) / blksize;
 1414 
 1415         ASSERT_VOP_LOCKED(vp, "vtruncbuf");
 1416 restart:
 1417         bo = &vp->v_bufobj;
 1418         BO_LOCK(bo);
 1419         anyfreed = 1;
 1420         for (;anyfreed;) {
 1421                 anyfreed = 0;
 1422                 TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
 1423                         if (bp->b_lblkno < trunclbn)
 1424                                 continue;
 1425                         if (BUF_LOCK(bp,
 1426                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1427                             BO_LOCKPTR(bo)) == ENOLCK)
 1428                                 goto restart;
 1429 
 1430                         bremfree(bp);
 1431                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1432                         bp->b_flags &= ~B_ASYNC;
 1433                         brelse(bp);
 1434                         anyfreed = 1;
 1435 
 1436                         BO_LOCK(bo);
 1437                         if (nbp != NULL &&
 1438                             (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
 1439                             (nbp->b_vp != vp) ||
 1440                             (nbp->b_flags & B_DELWRI))) {
 1441                                 BO_UNLOCK(bo);
 1442                                 goto restart;
 1443                         }
 1444                 }
 1445 
 1446                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1447                         if (bp->b_lblkno < trunclbn)
 1448                                 continue;
 1449                         if (BUF_LOCK(bp,
 1450                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1451                             BO_LOCKPTR(bo)) == ENOLCK)
 1452                                 goto restart;
 1453                         bremfree(bp);
 1454                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1455                         bp->b_flags &= ~B_ASYNC;
 1456                         brelse(bp);
 1457                         anyfreed = 1;
 1458 
 1459                         BO_LOCK(bo);
 1460                         if (nbp != NULL &&
 1461                             (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
 1462                             (nbp->b_vp != vp) ||
 1463                             (nbp->b_flags & B_DELWRI) == 0)) {
 1464                                 BO_UNLOCK(bo);
 1465                                 goto restart;
 1466                         }
 1467                 }
 1468         }
 1469 
 1470         if (length > 0) {
 1471 restartsync:
 1472                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1473                         if (bp->b_lblkno > 0)
 1474                                 continue;
 1475                         /*
 1476                          * Since we hold the vnode lock this should only
 1477                          * fail if we're racing with the buf daemon.
 1478                          */
 1479                         if (BUF_LOCK(bp,
 1480                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1481                             BO_LOCKPTR(bo)) == ENOLCK) {
 1482                                 goto restart;
 1483                         }
 1484                         VNASSERT((bp->b_flags & B_DELWRI), vp,
 1485                             ("buf(%p) on dirty queue without DELWRI", bp));
 1486 
 1487                         bremfree(bp);
 1488                         bawrite(bp);
 1489                         BO_LOCK(bo);
 1490                         goto restartsync;
 1491                 }
 1492         }
 1493 
 1494         bufobj_wwait(bo, 0, 0);
 1495         BO_UNLOCK(bo);
 1496         vnode_pager_setsize(vp, length);
 1497 
 1498         return (0);
 1499 }
 1500 
 1501 static void
 1502 buf_vlist_remove(struct buf *bp)
 1503 {
 1504         struct bufv *bv;
 1505 
 1506         KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
 1507         ASSERT_BO_WLOCKED(bp->b_bufobj);
 1508         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) !=
 1509             (BX_VNDIRTY|BX_VNCLEAN),
 1510             ("buf_vlist_remove: Buf %p is on two lists", bp));
 1511         if (bp->b_xflags & BX_VNDIRTY)
 1512                 bv = &bp->b_bufobj->bo_dirty;
 1513         else
 1514                 bv = &bp->b_bufobj->bo_clean;
 1515         BUF_PCTRIE_REMOVE(&bv->bv_root, bp->b_lblkno);
 1516         TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
 1517         bv->bv_cnt--;
 1518         bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
 1519 }
 1520 
 1521 /*
 1522  * Add the buffer to the sorted clean or dirty block list.
 1523  *
 1524  * NOTE: xflags is passed as a constant, optimizing this inline function!
 1525  */
 1526 static void
 1527 buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
 1528 {
 1529         struct bufv *bv;
 1530         struct buf *n;
 1531         int error;
 1532 
 1533         ASSERT_BO_WLOCKED(bo);
 1534         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
 1535             ("buf_vlist_add: Buf %p has existing xflags %d", bp, bp->b_xflags));
 1536         bp->b_xflags |= xflags;
 1537         if (xflags & BX_VNDIRTY)
 1538                 bv = &bo->bo_dirty;
 1539         else
 1540                 bv = &bo->bo_clean;
 1541 
 1542         /*
 1543          * Keep the list ordered.  Optimize empty list insertion.  Assume
 1544          * we tend to grow at the tail so lookup_le should usually be cheaper
 1545          * than _ge. 
 1546          */
 1547         if (bv->bv_cnt == 0 ||
 1548             bp->b_lblkno > TAILQ_LAST(&bv->bv_hd, buflists)->b_lblkno)
 1549                 TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
 1550         else if ((n = BUF_PCTRIE_LOOKUP_LE(&bv->bv_root, bp->b_lblkno)) == NULL)
 1551                 TAILQ_INSERT_HEAD(&bv->bv_hd, bp, b_bobufs);
 1552         else
 1553                 TAILQ_INSERT_AFTER(&bv->bv_hd, n, bp, b_bobufs);
 1554         error = BUF_PCTRIE_INSERT(&bv->bv_root, bp);
 1555         if (error)
 1556                 panic("buf_vlist_add:  Preallocated nodes insufficient.");
 1557         bv->bv_cnt++;
 1558 }
 1559 
 1560 /*
 1561  * Lookup a buffer using the splay tree.  Note that we specifically avoid
 1562  * shadow buffers used in background bitmap writes.
 1563  *
 1564  * This code isn't quite efficient as it could be because we are maintaining
 1565  * two sorted lists and do not know which list the block resides in.
 1566  *
 1567  * During a "make buildworld" the desired buffer is found at one of
 1568  * the roots more than 60% of the time.  Thus, checking both roots
 1569  * before performing either splay eliminates unnecessary splays on the
 1570  * first tree splayed.
 1571  */
 1572 struct buf *
 1573 gbincore(struct bufobj *bo, daddr_t lblkno)
 1574 {
 1575         struct buf *bp;
 1576 
 1577         ASSERT_BO_LOCKED(bo);
 1578         bp = BUF_PCTRIE_LOOKUP(&bo->bo_clean.bv_root, lblkno);
 1579         if (bp != NULL)
 1580                 return (bp);
 1581         return BUF_PCTRIE_LOOKUP(&bo->bo_dirty.bv_root, lblkno);
 1582 }
 1583 
 1584 /*
 1585  * Associate a buffer with a vnode.
 1586  */
 1587 void
 1588 bgetvp(struct vnode *vp, struct buf *bp)
 1589 {
 1590         struct bufobj *bo;
 1591 
 1592         bo = &vp->v_bufobj;
 1593         ASSERT_BO_WLOCKED(bo);
 1594         VNASSERT(bp->b_vp == NULL, bp->b_vp, ("bgetvp: not free"));
 1595 
 1596         CTR3(KTR_BUF, "bgetvp(%p) vp %p flags %X", bp, vp, bp->b_flags);
 1597         VNASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0, vp,
 1598             ("bgetvp: bp already attached! %p", bp));
 1599 
 1600         vhold(vp);
 1601         bp->b_vp = vp;
 1602         bp->b_bufobj = bo;
 1603         /*
 1604          * Insert onto list for new vnode.
 1605          */
 1606         buf_vlist_add(bp, bo, BX_VNCLEAN);
 1607 }
 1608 
 1609 /*
 1610  * Disassociate a buffer from a vnode.
 1611  */
 1612 void
 1613 brelvp(struct buf *bp)
 1614 {
 1615         struct bufobj *bo;
 1616         struct vnode *vp;
 1617 
 1618         CTR3(KTR_BUF, "brelvp(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
 1619         KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
 1620 
 1621         /*
 1622          * Delete from old vnode list, if on one.
 1623          */
 1624         vp = bp->b_vp;          /* XXX */
 1625         bo = bp->b_bufobj;
 1626         BO_LOCK(bo);
 1627         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1628                 buf_vlist_remove(bp);
 1629         else
 1630                 panic("brelvp: Buffer %p not on queue.", bp);
 1631         if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 1632                 bo->bo_flag &= ~BO_ONWORKLST;
 1633                 mtx_lock(&sync_mtx);
 1634                 LIST_REMOVE(bo, bo_synclist);
 1635                 syncer_worklist_len--;
 1636                 mtx_unlock(&sync_mtx);
 1637         }
 1638         bp->b_vp = NULL;
 1639         bp->b_bufobj = NULL;
 1640         BO_UNLOCK(bo);
 1641         vdrop(vp);
 1642 }
 1643 
 1644 /*
 1645  * Add an item to the syncer work queue.
 1646  */
 1647 static void
 1648 vn_syncer_add_to_worklist(struct bufobj *bo, int delay)
 1649 {
 1650         int slot;
 1651 
 1652         ASSERT_BO_WLOCKED(bo);
 1653 
 1654         mtx_lock(&sync_mtx);
 1655         if (bo->bo_flag & BO_ONWORKLST)
 1656                 LIST_REMOVE(bo, bo_synclist);
 1657         else {
 1658                 bo->bo_flag |= BO_ONWORKLST;
 1659                 syncer_worklist_len++;
 1660         }
 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], bo, bo_synclist);
 1667         mtx_unlock(&sync_mtx);
 1668 }
 1669 
 1670 static int
 1671 sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
 1672 {
 1673         int error, len;
 1674 
 1675         mtx_lock(&sync_mtx);
 1676         len = syncer_worklist_len - sync_vnode_count;
 1677         mtx_unlock(&sync_mtx);
 1678         error = SYSCTL_OUT(req, &len, sizeof(len));
 1679         return (error);
 1680 }
 1681 
 1682 SYSCTL_PROC(_vfs, OID_AUTO, worklist_len, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
 1683     sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
 1684 
 1685 static struct proc *updateproc;
 1686 static void sched_sync(void);
 1687 static struct kproc_desc up_kp = {
 1688         "syncer",
 1689         sched_sync,
 1690         &updateproc
 1691 };
 1692 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp);
 1693 
 1694 static int
 1695 sync_vnode(struct synclist *slp, struct bufobj **bo, struct thread *td)
 1696 {
 1697         struct vnode *vp;
 1698         struct mount *mp;
 1699 
 1700         *bo = LIST_FIRST(slp);
 1701         if (*bo == NULL)
 1702                 return (0);
 1703         vp = (*bo)->__bo_vnode; /* XXX */
 1704         if (VOP_ISLOCKED(vp) != 0 || VI_TRYLOCK(vp) == 0)
 1705                 return (1);
 1706         /*
 1707          * We use vhold in case the vnode does not
 1708          * successfully sync.  vhold prevents the vnode from
 1709          * going away when we unlock the sync_mtx so that
 1710          * we can acquire the vnode interlock.
 1711          */
 1712         vholdl(vp);
 1713         mtx_unlock(&sync_mtx);
 1714         VI_UNLOCK(vp);
 1715         if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
 1716                 vdrop(vp);
 1717                 mtx_lock(&sync_mtx);
 1718                 return (*bo == LIST_FIRST(slp));
 1719         }
 1720         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1721         (void) VOP_FSYNC(vp, MNT_LAZY, td);
 1722         VOP_UNLOCK(vp, 0);
 1723         vn_finished_write(mp);
 1724         BO_LOCK(*bo);
 1725         if (((*bo)->bo_flag & BO_ONWORKLST) != 0) {
 1726                 /*
 1727                  * Put us back on the worklist.  The worklist
 1728                  * routine will remove us from our current
 1729                  * position and then add us back in at a later
 1730                  * position.
 1731                  */
 1732                 vn_syncer_add_to_worklist(*bo, syncdelay);
 1733         }
 1734         BO_UNLOCK(*bo);
 1735         vdrop(vp);
 1736         mtx_lock(&sync_mtx);
 1737         return (0);
 1738 }
 1739 
 1740 /*
 1741  * System filesystem synchronizer daemon.
 1742  */
 1743 static void
 1744 sched_sync(void)
 1745 {
 1746         struct synclist *next, *slp;
 1747         struct bufobj *bo;
 1748         long starttime;
 1749         struct thread *td = curthread;
 1750         int last_work_seen;
 1751         int net_worklist_len;
 1752         int syncer_final_iter;
 1753         int first_printf;
 1754         int error;
 1755 
 1756         last_work_seen = 0;
 1757         syncer_final_iter = 0;
 1758         first_printf = 1;
 1759         syncer_state = SYNCER_RUNNING;
 1760         starttime = time_uptime;
 1761         td->td_pflags |= TDP_NORUNNINGBUF;
 1762 
 1763         EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
 1764             SHUTDOWN_PRI_LAST);
 1765 
 1766         mtx_lock(&sync_mtx);
 1767         for (;;) {
 1768                 if (syncer_state == SYNCER_FINAL_DELAY &&
 1769                     syncer_final_iter == 0) {
 1770                         mtx_unlock(&sync_mtx);
 1771                         kproc_suspend_check(td->td_proc);
 1772                         mtx_lock(&sync_mtx);
 1773                 }
 1774                 net_worklist_len = syncer_worklist_len - sync_vnode_count;
 1775                 if (syncer_state != SYNCER_RUNNING &&
 1776                     starttime != time_uptime) {
 1777                         if (first_printf) {
 1778                                 printf("\nSyncing disks, vnodes remaining...");
 1779                                 first_printf = 0;
 1780                         }
 1781                         printf("%d ", net_worklist_len);
 1782                 }
 1783                 starttime = time_uptime;
 1784 
 1785                 /*
 1786                  * Push files whose dirty time has expired.  Be careful
 1787                  * of interrupt race on slp queue.
 1788                  *
 1789                  * Skip over empty worklist slots when shutting down.
 1790                  */
 1791                 do {
 1792                         slp = &syncer_workitem_pending[syncer_delayno];
 1793                         syncer_delayno += 1;
 1794                         if (syncer_delayno == syncer_maxdelay)
 1795                                 syncer_delayno = 0;
 1796                         next = &syncer_workitem_pending[syncer_delayno];
 1797                         /*
 1798                          * If the worklist has wrapped since the
 1799                          * it was emptied of all but syncer vnodes,
 1800                          * switch to the FINAL_DELAY state and run
 1801                          * for one more second.
 1802                          */
 1803                         if (syncer_state == SYNCER_SHUTTING_DOWN &&
 1804                             net_worklist_len == 0 &&
 1805                             last_work_seen == syncer_delayno) {
 1806                                 syncer_state = SYNCER_FINAL_DELAY;
 1807                                 syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
 1808                         }
 1809                 } while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
 1810                     syncer_worklist_len > 0);
 1811 
 1812                 /*
 1813                  * Keep track of the last time there was anything
 1814                  * on the worklist other than syncer vnodes.
 1815                  * Return to the SHUTTING_DOWN state if any
 1816                  * new work appears.
 1817                  */
 1818                 if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
 1819                         last_work_seen = syncer_delayno;
 1820                 if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
 1821                         syncer_state = SYNCER_SHUTTING_DOWN;
 1822                 while (!LIST_EMPTY(slp)) {
 1823                         error = sync_vnode(slp, &bo, td);
 1824                         if (error == 1) {
 1825                                 LIST_REMOVE(bo, bo_synclist);
 1826                                 LIST_INSERT_HEAD(next, bo, bo_synclist);
 1827                                 continue;
 1828                         }
 1829 
 1830                         if (first_printf == 0)
 1831                                 wdog_kern_pat(WD_LASTVAL);
 1832 
 1833                 }
 1834                 if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
 1835                         syncer_final_iter--;
 1836                 /*
 1837                  * The variable rushjob allows the kernel to speed up the
 1838                  * processing of the filesystem syncer process. A rushjob
 1839                  * value of N tells the filesystem syncer to process the next
 1840                  * N seconds worth of work on its queue ASAP. Currently rushjob
 1841                  * is used by the soft update code to speed up the filesystem
 1842                  * syncer process when the incore state is getting so far
 1843                  * ahead of the disk that the kernel memory pool is being
 1844                  * threatened with exhaustion.
 1845                  */
 1846                 if (rushjob > 0) {
 1847                         rushjob -= 1;
 1848                         continue;
 1849                 }
 1850                 /*
 1851                  * Just sleep for a short period of time between
 1852                  * iterations when shutting down to allow some I/O
 1853                  * to happen.
 1854                  *
 1855                  * If it has taken us less than a second to process the
 1856                  * current work, then wait. Otherwise start right over
 1857                  * again. We can still lose time if any single round
 1858                  * takes more than two seconds, but it does not really
 1859                  * matter as we are just trying to generally pace the
 1860                  * filesystem activity.
 1861                  */
 1862                 if (syncer_state != SYNCER_RUNNING ||
 1863                     time_uptime == starttime) {
 1864                         thread_lock(td);
 1865                         sched_prio(td, PPAUSE);
 1866                         thread_unlock(td);
 1867                 }
 1868                 if (syncer_state != SYNCER_RUNNING)
 1869                         cv_timedwait(&sync_wakeup, &sync_mtx,
 1870                             hz / SYNCER_SHUTDOWN_SPEEDUP);
 1871                 else if (time_uptime == starttime)
 1872                         cv_timedwait(&sync_wakeup, &sync_mtx, hz);
 1873         }
 1874 }
 1875 
 1876 /*
 1877  * Request the syncer daemon to speed up its work.
 1878  * We never push it to speed up more than half of its
 1879  * normal turn time, otherwise it could take over the cpu.
 1880  */
 1881 int
 1882 speedup_syncer(void)
 1883 {
 1884         int ret = 0;
 1885 
 1886         mtx_lock(&sync_mtx);
 1887         if (rushjob < syncdelay / 2) {
 1888                 rushjob += 1;
 1889                 stat_rush_requests += 1;
 1890                 ret = 1;
 1891         }
 1892         mtx_unlock(&sync_mtx);
 1893         cv_broadcast(&sync_wakeup);
 1894         return (ret);
 1895 }
 1896 
 1897 /*
 1898  * Tell the syncer to speed up its work and run though its work
 1899  * list several times, then tell it to shut down.
 1900  */
 1901 static void
 1902 syncer_shutdown(void *arg, int howto)
 1903 {
 1904 
 1905         if (howto & RB_NOSYNC)
 1906                 return;
 1907         mtx_lock(&sync_mtx);
 1908         syncer_state = SYNCER_SHUTTING_DOWN;
 1909         rushjob = 0;
 1910         mtx_unlock(&sync_mtx);
 1911         cv_broadcast(&sync_wakeup);
 1912         kproc_shutdown(arg, howto);
 1913 }
 1914 
 1915 /*
 1916  * Reassign a buffer from one vnode to another.
 1917  * Used to assign file specific control information
 1918  * (indirect blocks) to the vnode to which they belong.
 1919  */
 1920 void
 1921 reassignbuf(struct buf *bp)
 1922 {
 1923         struct vnode *vp;
 1924         struct bufobj *bo;
 1925         int delay;
 1926 #ifdef INVARIANTS
 1927         struct bufv *bv;
 1928 #endif
 1929 
 1930         vp = bp->b_vp;
 1931         bo = bp->b_bufobj;
 1932         ++reassignbufcalls;
 1933 
 1934         CTR3(KTR_BUF, "reassignbuf(%p) vp %p flags %X",
 1935             bp, bp->b_vp, bp->b_flags);
 1936         /*
 1937          * B_PAGING flagged buffers cannot be reassigned because their vp
 1938          * is not fully linked in.
 1939          */
 1940         if (bp->b_flags & B_PAGING)
 1941                 panic("cannot reassign paging buffer");
 1942 
 1943         /*
 1944          * Delete from old vnode list, if on one.
 1945          */
 1946         BO_LOCK(bo);
 1947         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1948                 buf_vlist_remove(bp);
 1949         else
 1950                 panic("reassignbuf: Buffer %p not on queue.", bp);
 1951         /*
 1952          * If dirty, put on list of dirty buffers; otherwise insert onto list
 1953          * of clean buffers.
 1954          */
 1955         if (bp->b_flags & B_DELWRI) {
 1956                 if ((bo->bo_flag & BO_ONWORKLST) == 0) {
 1957                         switch (vp->v_type) {
 1958                         case VDIR:
 1959                                 delay = dirdelay;
 1960                                 break;
 1961                         case VCHR:
 1962                                 delay = metadelay;
 1963                                 break;
 1964                         default:
 1965                                 delay = filedelay;
 1966                         }
 1967                         vn_syncer_add_to_worklist(bo, delay);
 1968                 }
 1969                 buf_vlist_add(bp, bo, BX_VNDIRTY);
 1970         } else {
 1971                 buf_vlist_add(bp, bo, BX_VNCLEAN);
 1972 
 1973                 if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 1974                         mtx_lock(&sync_mtx);
 1975                         LIST_REMOVE(bo, bo_synclist);
 1976                         syncer_worklist_len--;
 1977                         mtx_unlock(&sync_mtx);
 1978                         bo->bo_flag &= ~BO_ONWORKLST;
 1979                 }
 1980         }
 1981 #ifdef INVARIANTS
 1982         bv = &bo->bo_clean;
 1983         bp = TAILQ_FIRST(&bv->bv_hd);
 1984         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1985             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1986         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 1987         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1988             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1989         bv = &bo->bo_dirty;
 1990         bp = TAILQ_FIRST(&bv->bv_hd);
 1991         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1992             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1993         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 1994         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1995             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1996 #endif
 1997         BO_UNLOCK(bo);
 1998 }
 1999 
 2000 /*
 2001  * Increment the use and hold counts on the vnode, taking care to reference
 2002  * the driver's usecount if this is a chardev.  The vholdl() will remove
 2003  * the vnode from the free list if it is presently free.  Requires the
 2004  * vnode interlock and returns with it held.
 2005  */
 2006 static void
 2007 v_incr_usecount(struct vnode *vp)
 2008 {
 2009 
 2010         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2011         vp->v_usecount++;
 2012         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2013                 dev_lock();
 2014                 vp->v_rdev->si_usecount++;
 2015                 dev_unlock();
 2016         }
 2017         vholdl(vp);
 2018 }
 2019 
 2020 /*
 2021  * Turn a holdcnt into a use+holdcnt such that only one call to
 2022  * v_decr_usecount is needed.
 2023  */
 2024 static void
 2025 v_upgrade_usecount(struct vnode *vp)
 2026 {
 2027 
 2028         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2029         vp->v_usecount++;
 2030         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2031                 dev_lock();
 2032                 vp->v_rdev->si_usecount++;
 2033                 dev_unlock();
 2034         }
 2035 }
 2036 
 2037 /*
 2038  * Decrement the vnode use and hold count along with the driver's usecount
 2039  * if this is a chardev.  The vdropl() below releases the vnode interlock
 2040  * as it may free the vnode.
 2041  */
 2042 static void
 2043 v_decr_usecount(struct vnode *vp)
 2044 {
 2045 
 2046         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2047         VNASSERT(vp->v_usecount > 0, vp,
 2048             ("v_decr_usecount: negative usecount"));
 2049         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2050         vp->v_usecount--;
 2051         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2052                 dev_lock();
 2053                 vp->v_rdev->si_usecount--;
 2054                 dev_unlock();
 2055         }
 2056         vdropl(vp);
 2057 }
 2058 
 2059 /*
 2060  * Decrement only the use count and driver use count.  This is intended to
 2061  * be paired with a follow on vdropl() to release the remaining hold count.
 2062  * In this way we may vgone() a vnode with a 0 usecount without risk of
 2063  * having it end up on a free list because the hold count is kept above 0.
 2064  */
 2065 static void
 2066 v_decr_useonly(struct vnode *vp)
 2067 {
 2068 
 2069         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2070         VNASSERT(vp->v_usecount > 0, vp,
 2071             ("v_decr_useonly: negative usecount"));
 2072         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2073         vp->v_usecount--;
 2074         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2075                 dev_lock();
 2076                 vp->v_rdev->si_usecount--;
 2077                 dev_unlock();
 2078         }
 2079 }
 2080 
 2081 /*
 2082  * Grab a particular vnode from the free list, increment its
 2083  * reference count and lock it.  VI_DOOMED is set if the vnode
 2084  * is being destroyed.  Only callers who specify LK_RETRY will
 2085  * see doomed vnodes.  If inactive processing was delayed in
 2086  * vput try to do it here.
 2087  */
 2088 int
 2089 vget(struct vnode *vp, int flags, struct thread *td)
 2090 {
 2091         int error;
 2092 
 2093         error = 0;
 2094         VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
 2095             ("vget: invalid lock operation"));
 2096         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 2097 
 2098         if ((flags & LK_INTERLOCK) == 0)
 2099                 VI_LOCK(vp);
 2100         vholdl(vp);
 2101         if ((error = vn_lock(vp, flags | LK_INTERLOCK)) != 0) {
 2102                 vdrop(vp);
 2103                 CTR2(KTR_VFS, "%s: impossible to lock vnode %p", __func__,
 2104                     vp);
 2105                 return (error);
 2106         }
 2107         if (vp->v_iflag & VI_DOOMED && (flags & LK_RETRY) == 0)
 2108                 panic("vget: vn_lock failed to return ENOENT\n");
 2109         VI_LOCK(vp);
 2110         /* Upgrade our holdcnt to a usecount. */
 2111         v_upgrade_usecount(vp);
 2112         /*
 2113          * We don't guarantee that any particular close will
 2114          * trigger inactive processing so just make a best effort
 2115          * here at preventing a reference to a removed file.  If
 2116          * we don't succeed no harm is done.
 2117          */
 2118         if (vp->v_iflag & VI_OWEINACT) {
 2119                 if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE &&
 2120                     (flags & LK_NOWAIT) == 0)
 2121                         vinactive(vp, td);
 2122                 vp->v_iflag &= ~VI_OWEINACT;
 2123         }
 2124         VI_UNLOCK(vp);
 2125         return (0);
 2126 }
 2127 
 2128 /*
 2129  * Increase the reference count of a vnode.
 2130  */
 2131 void
 2132 vref(struct vnode *vp)
 2133 {
 2134 
 2135         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2136         VI_LOCK(vp);
 2137         v_incr_usecount(vp);
 2138         VI_UNLOCK(vp);
 2139 }
 2140 
 2141 /*
 2142  * Return reference count of a vnode.
 2143  *
 2144  * The results of this call are only guaranteed when some mechanism other
 2145  * than the VI lock is used to stop other processes from gaining references
 2146  * to the vnode.  This may be the case if the caller holds the only reference.
 2147  * This is also useful when stale data is acceptable as race conditions may
 2148  * be accounted for by some other means.
 2149  */
 2150 int
 2151 vrefcnt(struct vnode *vp)
 2152 {
 2153         int usecnt;
 2154 
 2155         VI_LOCK(vp);
 2156         usecnt = vp->v_usecount;
 2157         VI_UNLOCK(vp);
 2158 
 2159         return (usecnt);
 2160 }
 2161 
 2162 #define VPUTX_VRELE     1
 2163 #define VPUTX_VPUT      2
 2164 #define VPUTX_VUNREF    3
 2165 
 2166 static void
 2167 vputx(struct vnode *vp, int func)
 2168 {
 2169         int error;
 2170 
 2171         KASSERT(vp != NULL, ("vputx: null vp"));
 2172         if (func == VPUTX_VUNREF)
 2173                 ASSERT_VOP_LOCKED(vp, "vunref");
 2174         else if (func == VPUTX_VPUT)
 2175                 ASSERT_VOP_LOCKED(vp, "vput");
 2176         else
 2177                 KASSERT(func == VPUTX_VRELE, ("vputx: wrong func"));
 2178         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2179         VI_LOCK(vp);
 2180 
 2181         /* Skip this v_writecount check if we're going to panic below. */
 2182         VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
 2183             ("vputx: missed vn_close"));
 2184         error = 0;
 2185 
 2186         if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
 2187             vp->v_usecount == 1)) {
 2188                 if (func == VPUTX_VPUT)
 2189                         VOP_UNLOCK(vp, 0);
 2190                 v_decr_usecount(vp);
 2191                 return;
 2192         }
 2193 
 2194         if (vp->v_usecount != 1) {
 2195                 vprint("vputx: negative ref count", vp);
 2196                 panic("vputx: negative ref cnt");
 2197         }
 2198         CTR2(KTR_VFS, "%s: return vnode %p to the freelist", __func__, vp);
 2199         /*
 2200          * We want to hold the vnode until the inactive finishes to
 2201          * prevent vgone() races.  We drop the use count here and the
 2202          * hold count below when we're done.
 2203          */
 2204         v_decr_useonly(vp);
 2205         /*
 2206          * We must call VOP_INACTIVE with the node locked. Mark
 2207          * as VI_DOINGINACT to avoid recursion.
 2208          */
 2209         vp->v_iflag |= VI_OWEINACT;
 2210         switch (func) {
 2211         case VPUTX_VRELE:
 2212                 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK);
 2213                 VI_LOCK(vp);
 2214                 break;
 2215         case VPUTX_VPUT:
 2216                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
 2217                         error = VOP_LOCK(vp, LK_UPGRADE | LK_INTERLOCK |
 2218                             LK_NOWAIT);
 2219                         VI_LOCK(vp);
 2220                 }
 2221                 break;
 2222         case VPUTX_VUNREF:
 2223                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
 2224                         error = VOP_LOCK(vp, LK_TRYUPGRADE | LK_INTERLOCK);
 2225                         VI_LOCK(vp);
 2226                 }
 2227                 break;
 2228         }
 2229         if (vp->v_usecount > 0)
 2230                 vp->v_iflag &= ~VI_OWEINACT;
 2231         if (error == 0) {
 2232                 if (vp->v_iflag & VI_OWEINACT)
 2233                         vinactive(vp, curthread);
 2234                 if (func != VPUTX_VUNREF)
 2235                         VOP_UNLOCK(vp, 0);
 2236         }
 2237         vdropl(vp);
 2238 }
 2239 
 2240 /*
 2241  * Vnode put/release.
 2242  * If count drops to zero, call inactive routine and return to freelist.
 2243  */
 2244 void
 2245 vrele(struct vnode *vp)
 2246 {
 2247 
 2248         vputx(vp, VPUTX_VRELE);
 2249 }
 2250 
 2251 /*
 2252  * Release an already locked vnode.  This give the same effects as
 2253  * unlock+vrele(), but takes less time and avoids releasing and
 2254  * re-aquiring the lock (as vrele() acquires the lock internally.)
 2255  */
 2256 void
 2257 vput(struct vnode *vp)
 2258 {
 2259 
 2260         vputx(vp, VPUTX_VPUT);
 2261 }
 2262 
 2263 /*
 2264  * Release an exclusively locked vnode. Do not unlock the vnode lock.
 2265  */
 2266 void
 2267 vunref(struct vnode *vp)
 2268 {
 2269 
 2270         vputx(vp, VPUTX_VUNREF);
 2271 }
 2272 
 2273 /*
 2274  * Somebody doesn't want the vnode recycled.
 2275  */
 2276 void
 2277 vhold(struct vnode *vp)
 2278 {
 2279 
 2280         VI_LOCK(vp);
 2281         vholdl(vp);
 2282         VI_UNLOCK(vp);
 2283 }
 2284 
 2285 /*
 2286  * Increase the hold count and activate if this is the first reference.
 2287  */
 2288 void
 2289 vholdl(struct vnode *vp)
 2290 {
 2291         struct mount *mp;
 2292 
 2293         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2294         vp->v_holdcnt++;
 2295         if (!VSHOULDBUSY(vp))
 2296                 return;
 2297         ASSERT_VI_LOCKED(vp, "vholdl");
 2298         VNASSERT((vp->v_iflag & VI_FREE) != 0, vp, ("vnode not free"));
 2299         VNASSERT(vp->v_op != NULL, vp, ("vholdl: vnode already reclaimed."));
 2300         /*
 2301          * Remove a vnode from the free list, mark it as in use,
 2302          * and put it on the active list.
 2303          */
 2304         mtx_lock(&vnode_free_list_mtx);
 2305         TAILQ_REMOVE(&vnode_free_list, vp, v_actfreelist);
 2306         freevnodes--;
 2307         vp->v_iflag &= ~(VI_FREE|VI_AGE);
 2308         KASSERT((vp->v_iflag & VI_ACTIVE) == 0,
 2309             ("Activating already active vnode"));
 2310         vp->v_iflag |= VI_ACTIVE;
 2311         mp = vp->v_mount;
 2312         TAILQ_INSERT_HEAD(&mp->mnt_activevnodelist, vp, v_actfreelist);
 2313         mp->mnt_activevnodelistsize++;
 2314         mtx_unlock(&vnode_free_list_mtx);
 2315 }
 2316 
 2317 /*
 2318  * Note that there is one less who cares about this vnode.
 2319  * vdrop() is the opposite of vhold().
 2320  */
 2321 void
 2322 vdrop(struct vnode *vp)
 2323 {
 2324 
 2325         VI_LOCK(vp);
 2326         vdropl(vp);
 2327 }
 2328 
 2329 /*
 2330  * Drop the hold count of the vnode.  If this is the last reference to
 2331  * the vnode we place it on the free list unless it has been vgone'd
 2332  * (marked VI_DOOMED) in which case we will free it.
 2333  */
 2334 void
 2335 vdropl(struct vnode *vp)
 2336 {
 2337         struct bufobj *bo;
 2338         struct mount *mp;
 2339         int active;
 2340 
 2341         ASSERT_VI_LOCKED(vp, "vdropl");
 2342         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2343         if (vp->v_holdcnt <= 0)
 2344                 panic("vdrop: holdcnt %d", vp->v_holdcnt);
 2345         vp->v_holdcnt--;
 2346         if (vp->v_holdcnt > 0) {
 2347                 VI_UNLOCK(vp);
 2348                 return;
 2349         }
 2350         if ((vp->v_iflag & VI_DOOMED) == 0) {
 2351                 /*
 2352                  * Mark a vnode as free: remove it from its active list
 2353                  * and put it up for recycling on the freelist.
 2354                  */
 2355                 VNASSERT(vp->v_op != NULL, vp,
 2356                     ("vdropl: vnode already reclaimed."));
 2357                 VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
 2358                     ("vnode already free"));
 2359                 VNASSERT(VSHOULDFREE(vp), vp,
 2360                     ("vdropl: freeing when we shouldn't"));
 2361                 active = vp->v_iflag & VI_ACTIVE;
 2362                 vp->v_iflag &= ~VI_ACTIVE;
 2363                 mp = vp->v_mount;
 2364                 mtx_lock(&vnode_free_list_mtx);
 2365                 if (active) {
 2366                         TAILQ_REMOVE(&mp->mnt_activevnodelist, vp,
 2367                             v_actfreelist);
 2368                         mp->mnt_activevnodelistsize--;
 2369                 }
 2370                 if (vp->v_iflag & VI_AGE) {
 2371                         TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_actfreelist);
 2372                 } else {
 2373                         TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_actfreelist);
 2374                 }
 2375                 freevnodes++;
 2376                 vp->v_iflag &= ~VI_AGE;
 2377                 vp->v_iflag |= VI_FREE;
 2378                 mtx_unlock(&vnode_free_list_mtx);
 2379                 VI_UNLOCK(vp);
 2380                 return;
 2381         }
 2382         /*
 2383          * The vnode has been marked for destruction, so free it.
 2384          */
 2385         CTR2(KTR_VFS, "%s: destroying the vnode %p", __func__, vp);
 2386         mtx_lock(&vnode_free_list_mtx);
 2387         numvnodes--;
 2388         mtx_unlock(&vnode_free_list_mtx);
 2389         bo = &vp->v_bufobj;
 2390         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
 2391             ("cleaned vnode still on the free list."));
 2392         VNASSERT(vp->v_data == NULL, vp, ("cleaned vnode isn't"));
 2393         VNASSERT(vp->v_holdcnt == 0, vp, ("Non-zero hold count"));
 2394         VNASSERT(vp->v_usecount == 0, vp, ("Non-zero use count"));
 2395         VNASSERT(vp->v_writecount == 0, vp, ("Non-zero write count"));
 2396         VNASSERT(bo->bo_numoutput == 0, vp, ("Clean vnode has pending I/O's"));
 2397         VNASSERT(bo->bo_clean.bv_cnt == 0, vp, ("cleanbufcnt not 0"));
 2398         VNASSERT(pctrie_is_empty(&bo->bo_clean.bv_root), vp,
 2399             ("clean blk trie not empty"));
 2400         VNASSERT(bo->bo_dirty.bv_cnt == 0, vp, ("dirtybufcnt not 0"));
 2401         VNASSERT(pctrie_is_empty(&bo->bo_dirty.bv_root), vp,
 2402             ("dirty blk trie not empty"));
 2403         VNASSERT(TAILQ_EMPTY(&vp->v_cache_dst), vp, ("vp has namecache dst"));
 2404         VNASSERT(LIST_EMPTY(&vp->v_cache_src), vp, ("vp has namecache src"));
 2405         VNASSERT(vp->v_cache_dd == NULL, vp, ("vp has namecache for .."));
 2406         VI_UNLOCK(vp);
 2407 #ifdef MAC
 2408         mac_vnode_destroy(vp);
 2409 #endif
 2410         if (vp->v_pollinfo != NULL)
 2411                 destroy_vpollinfo(vp->v_pollinfo);
 2412 #ifdef INVARIANTS
 2413         /* XXX Elsewhere we detect an already freed vnode via NULL v_op. */
 2414         vp->v_op = NULL;
 2415 #endif
 2416         rangelock_destroy(&vp->v_rl);
 2417         lockdestroy(vp->v_vnlock);
 2418         mtx_destroy(&vp->v_interlock);
 2419         rw_destroy(BO_LOCKPTR(bo));
 2420         uma_zfree(vnode_zone, vp);
 2421 }
 2422 
 2423 /*
 2424  * Call VOP_INACTIVE on the vnode and manage the DOINGINACT and OWEINACT
 2425  * flags.  DOINGINACT prevents us from recursing in calls to vinactive.
 2426  * OWEINACT tracks whether a vnode missed a call to inactive due to a
 2427  * failed lock upgrade.
 2428  */
 2429 void
 2430 vinactive(struct vnode *vp, struct thread *td)
 2431 {
 2432         struct vm_object *obj;
 2433 
 2434         ASSERT_VOP_ELOCKED(vp, "vinactive");
 2435         ASSERT_VI_LOCKED(vp, "vinactive");
 2436         VNASSERT((vp->v_iflag & VI_DOINGINACT) == 0, vp,
 2437             ("vinactive: recursed on VI_DOINGINACT"));
 2438         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2439         vp->v_iflag |= VI_DOINGINACT;
 2440         vp->v_iflag &= ~VI_OWEINACT;
 2441         VI_UNLOCK(vp);
 2442         /*
 2443          * Before moving off the active list, we must be sure that any
 2444          * modified pages are on the vnode's dirty list since these will
 2445          * no longer be checked once the vnode is on the inactive list.
 2446          * Because the vnode vm object keeps a hold reference on the vnode
 2447          * if there is at least one resident non-cached page, the vnode
 2448          * cannot leave the active list without the page cleanup done.
 2449          */
 2450         obj = vp->v_object;
 2451         if (obj != NULL && (obj->flags & OBJ_MIGHTBEDIRTY) != 0) {
 2452                 VM_OBJECT_WLOCK(obj);
 2453                 vm_object_page_clean(obj, 0, 0, OBJPC_NOSYNC);
 2454                 VM_OBJECT_WUNLOCK(obj);
 2455         }
 2456         VOP_INACTIVE(vp, td);
 2457         VI_LOCK(vp);
 2458         VNASSERT(vp->v_iflag & VI_DOINGINACT, vp,
 2459             ("vinactive: lost VI_DOINGINACT"));
 2460         vp->v_iflag &= ~VI_DOINGINACT;
 2461 }
 2462 
 2463 /*
 2464  * Remove any vnodes in the vnode table belonging to mount point mp.
 2465  *
 2466  * If FORCECLOSE is not specified, there should not be any active ones,
 2467  * return error if any are found (nb: this is a user error, not a
 2468  * system error). If FORCECLOSE is specified, detach any active vnodes
 2469  * that are found.
 2470  *
 2471  * If WRITECLOSE is set, only flush out regular file vnodes open for
 2472  * writing.
 2473  *
 2474  * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
 2475  *
 2476  * `rootrefs' specifies the base reference count for the root vnode
 2477  * of this filesystem. The root vnode is considered busy if its
 2478  * v_usecount exceeds this value. On a successful return, vflush(, td)
 2479  * will call vrele() on the root vnode exactly rootrefs times.
 2480  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
 2481  * be zero.
 2482  */
 2483 #ifdef DIAGNOSTIC
 2484 static int busyprt = 0;         /* print out busy vnodes */
 2485 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "Print out busy vnodes");
 2486 #endif
 2487 
 2488 int
 2489 vflush(struct mount *mp, int rootrefs, int flags, struct thread *td)
 2490 {
 2491         struct vnode *vp, *mvp, *rootvp = NULL;
 2492         struct vattr vattr;
 2493         int busy = 0, error;
 2494 
 2495         CTR4(KTR_VFS, "%s: mp %p with rootrefs %d and flags %d", __func__, mp,
 2496             rootrefs, flags);
 2497         if (rootrefs > 0) {
 2498                 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
 2499                     ("vflush: bad args"));
 2500                 /*
 2501                  * Get the filesystem root vnode. We can vput() it
 2502                  * immediately, since with rootrefs > 0, it won't go away.
 2503                  */
 2504                 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rootvp)) != 0) {
 2505                         CTR2(KTR_VFS, "%s: vfs_root lookup failed with %d",
 2506                             __func__, error);
 2507                         return (error);
 2508                 }
 2509                 vput(rootvp);
 2510         }
 2511 loop:
 2512         MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
 2513                 vholdl(vp);
 2514                 error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE);
 2515                 if (error) {
 2516                         vdrop(vp);
 2517                         MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
 2518                         goto loop;
 2519                 }
 2520                 /*
 2521                  * Skip over a vnodes marked VV_SYSTEM.
 2522                  */
 2523                 if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
 2524                         VOP_UNLOCK(vp, 0);
 2525                         vdrop(vp);
 2526                         continue;
 2527                 }
 2528                 /*
 2529                  * If WRITECLOSE is set, flush out unlinked but still open
 2530                  * files (even if open only for reading) and regular file
 2531                  * vnodes open for writing.
 2532                  */
 2533                 if (flags & WRITECLOSE) {
 2534                         if (vp->v_object != NULL) {
 2535                                 VM_OBJECT_WLOCK(vp->v_object);
 2536                                 vm_object_page_clean(vp->v_object, 0, 0, 0);
 2537                                 VM_OBJECT_WUNLOCK(vp->v_object);
 2538                         }
 2539                         error = VOP_FSYNC(vp, MNT_WAIT, td);
 2540                         if (error != 0) {
 2541                                 VOP_UNLOCK(vp, 0);
 2542                                 vdrop(vp);
 2543                                 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
 2544                                 return (error);
 2545                         }
 2546                         error = VOP_GETATTR(vp, &vattr, td->td_ucred);
 2547                         VI_LOCK(vp);
 2548 
 2549                         if ((vp->v_type == VNON ||
 2550                             (error == 0 && vattr.va_nlink > 0)) &&
 2551                             (vp->v_writecount == 0 || vp->v_type != VREG)) {
 2552                                 VOP_UNLOCK(vp, 0);
 2553                                 vdropl(vp);
 2554                                 continue;
 2555                         }
 2556                 } else
 2557                         VI_LOCK(vp);
 2558                 /*
 2559                  * With v_usecount == 0, all we need to do is clear out the
 2560                  * vnode data structures and we are done.
 2561                  *
 2562                  * If FORCECLOSE is set, forcibly close the vnode.
 2563                  */
 2564                 if (vp->v_usecount == 0 || (flags & FORCECLOSE)) {
 2565                         VNASSERT(vp->v_usecount == 0 ||
 2566                             (vp->v_type != VCHR && vp->v_type != VBLK), vp,
 2567                             ("device VNODE %p is FORCECLOSED", vp));
 2568                         vgonel(vp);
 2569                 } else {
 2570                         busy++;
 2571 #ifdef DIAGNOSTIC
 2572                         if (busyprt)
 2573                                 vprint("vflush: busy vnode", vp);
 2574 #endif
 2575                 }
 2576                 VOP_UNLOCK(vp, 0);
 2577                 vdropl(vp);
 2578         }
 2579         if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
 2580                 /*
 2581                  * If just the root vnode is busy, and if its refcount
 2582                  * is equal to `rootrefs', then go ahead and kill it.
 2583                  */
 2584                 VI_LOCK(rootvp);
 2585                 KASSERT(busy > 0, ("vflush: not busy"));
 2586                 VNASSERT(rootvp->v_usecount >= rootrefs, rootvp,
 2587                     ("vflush: usecount %d < rootrefs %d",
 2588                      rootvp->v_usecount, rootrefs));
 2589                 if (busy == 1 && rootvp->v_usecount == rootrefs) {
 2590                         VOP_LOCK(rootvp, LK_EXCLUSIVE|LK_INTERLOCK);
 2591                         vgone(rootvp);
 2592                         VOP_UNLOCK(rootvp, 0);
 2593                         busy = 0;
 2594                 } else
 2595                         VI_UNLOCK(rootvp);
 2596         }
 2597         if (busy) {
 2598                 CTR2(KTR_VFS, "%s: failing as %d vnodes are busy", __func__,
 2599                     busy);
 2600                 return (EBUSY);
 2601         }
 2602         for (; rootrefs > 0; rootrefs--)
 2603                 vrele(rootvp);
 2604         return (0);
 2605 }
 2606 
 2607 /*
 2608  * Recycle an unused vnode to the front of the free list.
 2609  */
 2610 int
 2611 vrecycle(struct vnode *vp)
 2612 {
 2613         int recycled;
 2614 
 2615         ASSERT_VOP_ELOCKED(vp, "vrecycle");
 2616         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2617         recycled = 0;
 2618         VI_LOCK(vp);
 2619         if (vp->v_usecount == 0) {
 2620                 recycled = 1;
 2621                 vgonel(vp);
 2622         }
 2623         VI_UNLOCK(vp);
 2624         return (recycled);
 2625 }
 2626 
 2627 /*
 2628  * Eliminate all activity associated with a vnode
 2629  * in preparation for reuse.
 2630  */
 2631 void
 2632 vgone(struct vnode *vp)
 2633 {
 2634         VI_LOCK(vp);
 2635         vgonel(vp);
 2636         VI_UNLOCK(vp);
 2637 }
 2638 
 2639 static void
 2640 notify_lowervp_vfs_dummy(struct mount *mp __unused,
 2641     struct vnode *lowervp __unused)
 2642 {
 2643 }
 2644 
 2645 /*
 2646  * Notify upper mounts about reclaimed or unlinked vnode.
 2647  */
 2648 void
 2649 vfs_notify_upper(struct vnode *vp, int event)
 2650 {
 2651         static struct vfsops vgonel_vfsops = {
 2652                 .vfs_reclaim_lowervp = notify_lowervp_vfs_dummy,
 2653                 .vfs_unlink_lowervp = notify_lowervp_vfs_dummy,
 2654         };
 2655         struct mount *mp, *ump, *mmp;
 2656 
 2657         mp = vp->v_mount;
 2658         if (mp == NULL)
 2659                 return;
 2660 
 2661         MNT_ILOCK(mp);
 2662         if (TAILQ_EMPTY(&mp->mnt_uppers))
 2663                 goto unlock;
 2664         MNT_IUNLOCK(mp);
 2665         mmp = malloc(sizeof(struct mount), M_TEMP, M_WAITOK | M_ZERO);
 2666         mmp->mnt_op = &vgonel_vfsops;
 2667         mmp->mnt_kern_flag |= MNTK_MARKER;
 2668         MNT_ILOCK(mp);
 2669         mp->mnt_kern_flag |= MNTK_VGONE_UPPER;
 2670         for (ump = TAILQ_FIRST(&mp->mnt_uppers); ump != NULL;) {
 2671                 if ((ump->mnt_kern_flag & MNTK_MARKER) != 0) {
 2672                         ump = TAILQ_NEXT(ump, mnt_upper_link);
 2673                         continue;
 2674                 }
 2675                 TAILQ_INSERT_AFTER(&mp->mnt_uppers, ump, mmp, mnt_upper_link);
 2676                 MNT_IUNLOCK(mp);
 2677                 switch (event) {
 2678                 case VFS_NOTIFY_UPPER_RECLAIM:
 2679                         VFS_RECLAIM_LOWERVP(ump, vp);
 2680                         break;
 2681                 case VFS_NOTIFY_UPPER_UNLINK:
 2682                         VFS_UNLINK_LOWERVP(ump, vp);
 2683                         break;
 2684                 default:
 2685                         KASSERT(0, ("invalid event %d", event));
 2686                         break;
 2687                 }
 2688                 MNT_ILOCK(mp);
 2689                 ump = TAILQ_NEXT(mmp, mnt_upper_link);
 2690                 TAILQ_REMOVE(&mp->mnt_uppers, mmp, mnt_upper_link);
 2691         }
 2692         free(mmp, M_TEMP);
 2693         mp->mnt_kern_flag &= ~MNTK_VGONE_UPPER;
 2694         if ((mp->mnt_kern_flag & MNTK_VGONE_WAITER) != 0) {
 2695                 mp->mnt_kern_flag &= ~MNTK_VGONE_WAITER;
 2696                 wakeup(&mp->mnt_uppers);
 2697         }
 2698 unlock:
 2699         MNT_IUNLOCK(mp);
 2700 }
 2701 
 2702 /*
 2703  * vgone, with the vp interlock held.
 2704  */
 2705 void
 2706 vgonel(struct vnode *vp)
 2707 {
 2708         struct thread *td;
 2709         int oweinact;
 2710         int active;
 2711         struct mount *mp;
 2712 
 2713         ASSERT_VOP_ELOCKED(vp, "vgonel");
 2714         ASSERT_VI_LOCKED(vp, "vgonel");
 2715         VNASSERT(vp->v_holdcnt, vp,
 2716             ("vgonel: vp %p has no reference.", vp));
 2717         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2718         td = curthread;
 2719 
 2720         /*
 2721          * Don't vgonel if we're already doomed.
 2722          */
 2723         if (vp->v_iflag & VI_DOOMED)
 2724                 return;
 2725         vp->v_iflag |= VI_DOOMED;
 2726 
 2727         /*
 2728          * Check to see if the vnode is in use.  If so, we have to call
 2729          * VOP_CLOSE() and VOP_INACTIVE().
 2730          */
 2731         active = vp->v_usecount;
 2732         oweinact = (vp->v_iflag & VI_OWEINACT);
 2733         VI_UNLOCK(vp);
 2734         vfs_notify_upper(vp, VFS_NOTIFY_UPPER_RECLAIM);
 2735 
 2736         /*
 2737          * Clean out any buffers associated with the vnode.
 2738          * If the flush fails, just toss the buffers.
 2739          */
 2740         mp = NULL;
 2741         if (!TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd))
 2742                 (void) vn_start_secondary_write(vp, &mp, V_WAIT);
 2743         if (vinvalbuf(vp, V_SAVE, 0, 0) != 0)
 2744                 vinvalbuf(vp, 0, 0, 0);
 2745 
 2746         /*
 2747          * If purging an active vnode, it must be closed and
 2748          * deactivated before being reclaimed.
 2749          */
 2750         if (active)
 2751                 VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
 2752         if (oweinact || active) {
 2753                 VI_LOCK(vp);
 2754                 if ((vp->v_iflag & VI_DOINGINACT) == 0)
 2755                         vinactive(vp, td);
 2756                 VI_UNLOCK(vp);
 2757         }
 2758         if (vp->v_type == VSOCK)
 2759                 vfs_unp_reclaim(vp);
 2760         /*
 2761          * Reclaim the vnode.
 2762          */
 2763         if (VOP_RECLAIM(vp, td))
 2764                 panic("vgone: cannot reclaim");
 2765         if (mp != NULL)
 2766                 vn_finished_secondary_write(mp);
 2767         VNASSERT(vp->v_object == NULL, vp,
 2768             ("vop_reclaim left v_object vp=%p, tag=%s", vp, vp->v_tag));
 2769         /*
 2770          * Clear the advisory locks and wake up waiting threads.
 2771          */
 2772         (void)VOP_ADVLOCKPURGE(vp);
 2773         /*
 2774          * Delete from old mount point vnode list.
 2775          */
 2776         delmntque(vp);
 2777         cache_purge(vp);
 2778         /*
 2779          * Done with purge, reset to the standard lock and invalidate
 2780          * the vnode.
 2781          */
 2782         VI_LOCK(vp);
 2783         vp->v_vnlock = &vp->v_lock;
 2784         vp->v_op = &dead_vnodeops;
 2785         vp->v_tag = "none";
 2786         vp->v_type = VBAD;
 2787 }
 2788 
 2789 /*
 2790  * Calculate the total number of references to a special device.
 2791  */
 2792 int
 2793 vcount(struct vnode *vp)
 2794 {
 2795         int count;
 2796 
 2797         dev_lock();
 2798         count = vp->v_rdev->si_usecount;
 2799         dev_unlock();
 2800         return (count);
 2801 }
 2802 
 2803 /*
 2804  * Same as above, but using the struct cdev *as argument
 2805  */
 2806 int
 2807 count_dev(struct cdev *dev)
 2808 {
 2809         int count;
 2810 
 2811         dev_lock();
 2812         count = dev->si_usecount;
 2813         dev_unlock();
 2814         return(count);
 2815 }
 2816 
 2817 /*
 2818  * Print out a description of a vnode.
 2819  */
 2820 static char *typename[] =
 2821 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD",
 2822  "VMARKER"};
 2823 
 2824 void
 2825 vn_printf(struct vnode *vp, const char *fmt, ...)
 2826 {
 2827         va_list ap;
 2828         char buf[256], buf2[16];
 2829         u_long flags;
 2830 
 2831         va_start(ap, fmt);
 2832         vprintf(fmt, ap);
 2833         va_end(ap);
 2834         printf("%p: ", (void *)vp);
 2835         printf("tag %s, type %s\n", vp->v_tag, typename[vp->v_type]);
 2836         printf("    usecount %d, writecount %d, refcount %d mountedhere %p\n",
 2837             vp->v_usecount, vp->v_writecount, vp->v_holdcnt, vp->v_mountedhere);
 2838         buf[0] = '\0';
 2839         buf[1] = '\0';
 2840         if (vp->v_vflag & VV_ROOT)
 2841                 strlcat(buf, "|VV_ROOT", sizeof(buf));
 2842         if (vp->v_vflag & VV_ISTTY)
 2843                 strlcat(buf, "|VV_ISTTY", sizeof(buf));
 2844         if (vp->v_vflag & VV_NOSYNC)
 2845                 strlcat(buf, "|VV_NOSYNC", sizeof(buf));
 2846         if (vp->v_vflag & VV_ETERNALDEV)
 2847                 strlcat(buf, "|VV_ETERNALDEV", sizeof(buf));
 2848         if (vp->v_vflag & VV_CACHEDLABEL)
 2849                 strlcat(buf, "|VV_CACHEDLABEL", sizeof(buf));
 2850         if (vp->v_vflag & VV_TEXT)
 2851                 strlcat(buf, "|VV_TEXT", sizeof(buf));
 2852         if (vp->v_vflag & VV_COPYONWRITE)
 2853                 strlcat(buf, "|VV_COPYONWRITE", sizeof(buf));
 2854         if (vp->v_vflag & VV_SYSTEM)
 2855                 strlcat(buf, "|VV_SYSTEM", sizeof(buf));
 2856         if (vp->v_vflag & VV_PROCDEP)
 2857                 strlcat(buf, "|VV_PROCDEP", sizeof(buf));
 2858         if (vp->v_vflag & VV_NOKNOTE)
 2859                 strlcat(buf, "|VV_NOKNOTE", sizeof(buf));
 2860         if (vp->v_vflag & VV_DELETED)
 2861                 strlcat(buf, "|VV_DELETED", sizeof(buf));
 2862         if (vp->v_vflag & VV_MD)
 2863                 strlcat(buf, "|VV_MD", sizeof(buf));
 2864         if (vp->v_vflag & VV_FORCEINSMQ)
 2865                 strlcat(buf, "|VV_FORCEINSMQ", sizeof(buf));
 2866         flags = vp->v_vflag & ~(VV_ROOT | VV_ISTTY | VV_NOSYNC | VV_ETERNALDEV |
 2867             VV_CACHEDLABEL | VV_TEXT | VV_COPYONWRITE | VV_SYSTEM | VV_PROCDEP |
 2868             VV_NOKNOTE | VV_DELETED | VV_MD | VV_FORCEINSMQ);
 2869         if (flags != 0) {
 2870                 snprintf(buf2, sizeof(buf2), "|VV(0x%lx)", flags);
 2871                 strlcat(buf, buf2, sizeof(buf));
 2872         }
 2873         if (vp->v_iflag & VI_MOUNT)
 2874                 strlcat(buf, "|VI_MOUNT", sizeof(buf));
 2875         if (vp->v_iflag & VI_AGE)
 2876                 strlcat(buf, "|VI_AGE", sizeof(buf));
 2877         if (vp->v_iflag & VI_DOOMED)
 2878                 strlcat(buf, "|VI_DOOMED", sizeof(buf));
 2879         if (vp->v_iflag & VI_FREE)
 2880                 strlcat(buf, "|VI_FREE", sizeof(buf));
 2881         if (vp->v_iflag & VI_ACTIVE)
 2882                 strlcat(buf, "|VI_ACTIVE", sizeof(buf));
 2883         if (vp->v_iflag & VI_DOINGINACT)
 2884                 strlcat(buf, "|VI_DOINGINACT", sizeof(buf));
 2885         if (vp->v_iflag & VI_OWEINACT)
 2886                 strlcat(buf, "|VI_OWEINACT", sizeof(buf));
 2887         flags = vp->v_iflag & ~(VI_MOUNT | VI_AGE | VI_DOOMED | VI_FREE |
 2888             VI_ACTIVE | VI_DOINGINACT | VI_OWEINACT);
 2889         if (flags != 0) {
 2890                 snprintf(buf2, sizeof(buf2), "|VI(0x%lx)", flags);
 2891                 strlcat(buf, buf2, sizeof(buf));
 2892         }
 2893         printf("    flags (%s)\n", buf + 1);
 2894         if (mtx_owned(VI_MTX(vp)))
 2895                 printf(" VI_LOCKed");
 2896         if (vp->v_object != NULL)
 2897                 printf("    v_object %p ref %d pages %d "
 2898                     "cleanbuf %d dirtybuf %d\n",
 2899                     vp->v_object, vp->v_object->ref_count,
 2900                     vp->v_object->resident_page_count,
 2901                     vp->v_bufobj.bo_dirty.bv_cnt,
 2902                     vp->v_bufobj.bo_clean.bv_cnt);
 2903         printf("    ");
 2904         lockmgr_printinfo(vp->v_vnlock);
 2905         if (vp->v_data != NULL)
 2906                 VOP_PRINT(vp);
 2907 }
 2908 
 2909 #ifdef DDB
 2910 /*
 2911  * List all of the locked vnodes in the system.
 2912  * Called when debugging the kernel.
 2913  */
 2914 DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
 2915 {
 2916         struct mount *mp;
 2917         struct vnode *vp;
 2918 
 2919         /*
 2920          * Note: because this is DDB, we can't obey the locking semantics
 2921          * for these structures, which means we could catch an inconsistent
 2922          * state and dereference a nasty pointer.  Not much to be done
 2923          * about that.
 2924          */
 2925         db_printf("Locked vnodes\n");
 2926         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 2927                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2928                         if (vp->v_type != VMARKER && VOP_ISLOCKED(vp))
 2929                                 vprint("", vp);
 2930                 }
 2931         }
 2932 }
 2933 
 2934 /*
 2935  * Show details about the given vnode.
 2936  */
 2937 DB_SHOW_COMMAND(vnode, db_show_vnode)
 2938 {
 2939         struct vnode *vp;
 2940 
 2941         if (!have_addr)
 2942                 return;
 2943         vp = (struct vnode *)addr;
 2944         vn_printf(vp, "vnode ");
 2945 }
 2946 
 2947 /*
 2948  * Show details about the given mount point.
 2949  */
 2950 DB_SHOW_COMMAND(mount, db_show_mount)
 2951 {
 2952         struct mount *mp;
 2953         struct vfsopt *opt;
 2954         struct statfs *sp;
 2955         struct vnode *vp;
 2956         char buf[512];
 2957         uint64_t mflags;
 2958         u_int flags;
 2959 
 2960         if (!have_addr) {
 2961                 /* No address given, print short info about all mount points. */
 2962                 TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 2963                         db_printf("%p %s on %s (%s)\n", mp,
 2964                             mp->mnt_stat.f_mntfromname,
 2965                             mp->mnt_stat.f_mntonname,
 2966                             mp->mnt_stat.f_fstypename);
 2967                         if (db_pager_quit)
 2968                                 break;
 2969                 }
 2970                 db_printf("\nMore info: show mount <addr>\n");
 2971                 return;
 2972         }
 2973 
 2974         mp = (struct mount *)addr;
 2975         db_printf("%p %s on %s (%s)\n", mp, mp->mnt_stat.f_mntfromname,
 2976             mp->mnt_stat.f_mntonname, mp->mnt_stat.f_fstypename);
 2977 
 2978         buf[0] = '\0';
 2979         mflags = mp->mnt_flag;
 2980 #define MNT_FLAG(flag)  do {                                            \
 2981         if (mflags & (flag)) {                                          \
 2982                 if (buf[0] != '\0')                                     \
 2983                         strlcat(buf, ", ", sizeof(buf));                \
 2984                 strlcat(buf, (#flag) + 4, sizeof(buf));                 \
 2985                 mflags &= ~(flag);                                      \
 2986         }                                                               \
 2987 } while (0)
 2988         MNT_FLAG(MNT_RDONLY);
 2989         MNT_FLAG(MNT_SYNCHRONOUS);
 2990         MNT_FLAG(MNT_NOEXEC);
 2991         MNT_FLAG(MNT_NOSUID);
 2992         MNT_FLAG(MNT_NFS4ACLS);
 2993         MNT_FLAG(MNT_UNION);
 2994         MNT_FLAG(MNT_ASYNC);
 2995         MNT_FLAG(MNT_SUIDDIR);
 2996         MNT_FLAG(MNT_SOFTDEP);
 2997         MNT_FLAG(MNT_NOSYMFOLLOW);
 2998         MNT_FLAG(MNT_GJOURNAL);
 2999         MNT_FLAG(MNT_MULTILABEL);
 3000         MNT_FLAG(MNT_ACLS);
 3001         MNT_FLAG(MNT_NOATIME);
 3002         MNT_FLAG(MNT_NOCLUSTERR);
 3003         MNT_FLAG(MNT_NOCLUSTERW);
 3004         MNT_FLAG(MNT_SUJ);
 3005         MNT_FLAG(MNT_EXRDONLY);
 3006         MNT_FLAG(MNT_EXPORTED);
 3007         MNT_FLAG(MNT_DEFEXPORTED);
 3008         MNT_FLAG(MNT_EXPORTANON);
 3009         MNT_FLAG(MNT_EXKERB);
 3010         MNT_FLAG(MNT_EXPUBLIC);
 3011         MNT_FLAG(MNT_LOCAL);
 3012         MNT_FLAG(MNT_QUOTA);
 3013         MNT_FLAG(MNT_ROOTFS);
 3014         MNT_FLAG(MNT_USER);
 3015         MNT_FLAG(MNT_IGNORE);
 3016         MNT_FLAG(MNT_UPDATE);
 3017         MNT_FLAG(MNT_DELEXPORT);
 3018         MNT_FLAG(MNT_RELOAD);
 3019         MNT_FLAG(MNT_FORCE);
 3020         MNT_FLAG(MNT_SNAPSHOT);
 3021         MNT_FLAG(MNT_BYFSID);
 3022 #undef MNT_FLAG
 3023         if (mflags != 0) {
 3024                 if (buf[0] != '\0')
 3025                         strlcat(buf, ", ", sizeof(buf));
 3026                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 3027                     "0x%016jx", mflags);
 3028         }
 3029         db_printf("    mnt_flag = %s\n", buf);
 3030 
 3031         buf[0] = '\0';
 3032         flags = mp->mnt_kern_flag;
 3033 #define MNT_KERN_FLAG(flag)     do {                                    \
 3034         if (flags & (flag)) {                                           \
 3035                 if (buf[0] != '\0')                                     \
 3036                         strlcat(buf, ", ", sizeof(buf));                \
 3037                 strlcat(buf, (#flag) + 5, sizeof(buf));                 \
 3038                 flags &= ~(flag);                                       \
 3039         }                                                               \
 3040 } while (0)
 3041         MNT_KERN_FLAG(MNTK_UNMOUNTF);
 3042         MNT_KERN_FLAG(MNTK_ASYNC);
 3043         MNT_KERN_FLAG(MNTK_SOFTDEP);
 3044         MNT_KERN_FLAG(MNTK_NOINSMNTQ);
 3045         MNT_KERN_FLAG(MNTK_DRAINING);
 3046         MNT_KERN_FLAG(MNTK_REFEXPIRE);
 3047         MNT_KERN_FLAG(MNTK_EXTENDED_SHARED);
 3048         MNT_KERN_FLAG(MNTK_SHARED_WRITES);
 3049         MNT_KERN_FLAG(MNTK_NO_IOPF);
 3050         MNT_KERN_FLAG(MNTK_VGONE_UPPER);
 3051         MNT_KERN_FLAG(MNTK_VGONE_WAITER);
 3052         MNT_KERN_FLAG(MNTK_LOOKUP_EXCL_DOTDOT);
 3053         MNT_KERN_FLAG(MNTK_MARKER);
 3054         MNT_KERN_FLAG(MNTK_NOASYNC);
 3055         MNT_KERN_FLAG(MNTK_UNMOUNT);
 3056         MNT_KERN_FLAG(MNTK_MWAIT);
 3057         MNT_KERN_FLAG(MNTK_SUSPEND);
 3058         MNT_KERN_FLAG(MNTK_SUSPEND2);
 3059         MNT_KERN_FLAG(MNTK_SUSPENDED);
 3060         MNT_KERN_FLAG(MNTK_LOOKUP_SHARED);
 3061         MNT_KERN_FLAG(MNTK_NOKNOTE);
 3062 #undef MNT_KERN_FLAG
 3063         if (flags != 0) {
 3064                 if (buf[0] != '\0')
 3065                         strlcat(buf, ", ", sizeof(buf));
 3066                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 3067                     "0x%08x", flags);
 3068         }
 3069         db_printf("    mnt_kern_flag = %s\n", buf);
 3070 
 3071         db_printf("    mnt_opt = ");
 3072         opt = TAILQ_FIRST(mp->mnt_opt);
 3073         if (opt != NULL) {
 3074                 db_printf("%s", opt->name);
 3075                 opt = TAILQ_NEXT(opt, link);
 3076                 while (opt != NULL) {
 3077                         db_printf(", %s", opt->name);
 3078                         opt = TAILQ_NEXT(opt, link);
 3079                 }
 3080         }
 3081         db_printf("\n");
 3082 
 3083         sp = &mp->mnt_stat;
 3084         db_printf("    mnt_stat = { version=%u type=%u flags=0x%016jx "
 3085             "bsize=%ju iosize=%ju blocks=%ju bfree=%ju bavail=%jd files=%ju "
 3086             "ffree=%jd syncwrites=%ju asyncwrites=%ju syncreads=%ju "
 3087             "asyncreads=%ju namemax=%u owner=%u fsid=[%d, %d] }\n",
 3088             (u_int)sp->f_version, (u_int)sp->f_type, (uintmax_t)sp->f_flags,
 3089             (uintmax_t)sp->f_bsize, (uintmax_t)sp->f_iosize,
 3090             (uintmax_t)sp->f_blocks, (uintmax_t)sp->f_bfree,
 3091             (intmax_t)sp->f_bavail, (uintmax_t)sp->f_files,
 3092             (intmax_t)sp->f_ffree, (uintmax_t)sp->f_syncwrites,
 3093             (uintmax_t)sp->f_asyncwrites, (uintmax_t)sp->f_syncreads,
 3094             (uintmax_t)sp->f_asyncreads, (u_int)sp->f_namemax,
 3095             (u_int)sp->f_owner, (int)sp->f_fsid.val[0], (int)sp->f_fsid.val[1]);
 3096 
 3097         db_printf("    mnt_cred = { uid=%u ruid=%u",
 3098             (u_int)mp->mnt_cred->cr_uid, (u_int)mp->mnt_cred->cr_ruid);
 3099         if (jailed(mp->mnt_cred))
 3100                 db_printf(", jail=%d", mp->mnt_cred->cr_prison->pr_id);
 3101         db_printf(" }\n");
 3102         db_printf("    mnt_ref = %d\n", mp->mnt_ref);
 3103         db_printf("    mnt_gen = %d\n", mp->mnt_gen);
 3104         db_printf("    mnt_nvnodelistsize = %d\n", mp->mnt_nvnodelistsize);
 3105         db_printf("    mnt_activevnodelistsize = %d\n",
 3106             mp->mnt_activevnodelistsize);
 3107         db_printf("    mnt_writeopcount = %d\n", mp->mnt_writeopcount);
 3108         db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
 3109         db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
 3110         db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
 3111         db_printf("    mnt_secondary_writes = %d\n", mp->mnt_secondary_writes);
 3112         db_printf("    mnt_secondary_accwrites = %d\n",
 3113             mp->mnt_secondary_accwrites);
 3114         db_printf("    mnt_gjprovider = %s\n",
 3115             mp->mnt_gjprovider != NULL ? mp->mnt_gjprovider : "NULL");
 3116 
 3117         db_printf("\n\nList of active vnodes\n");
 3118         TAILQ_FOREACH(vp, &mp->mnt_activevnodelist, v_actfreelist) {
 3119                 if (vp->v_type != VMARKER) {
 3120                         vn_printf(vp, "vnode ");
 3121                         if (db_pager_quit)
 3122                                 break;
 3123                 }
 3124         }
 3125         db_printf("\n\nList of inactive vnodes\n");
 3126         TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3127                 if (vp->v_type != VMARKER && (vp->v_iflag & VI_ACTIVE) == 0) {
 3128                         vn_printf(vp, "vnode ");
 3129                         if (db_pager_quit)
 3130                                 break;
 3131                 }
 3132         }
 3133 }
 3134 #endif  /* DDB */
 3135 
 3136 /*
 3137  * Fill in a struct xvfsconf based on a struct vfsconf.
 3138  */
 3139 static int
 3140 vfsconf2x(struct sysctl_req *req, struct vfsconf *vfsp)
 3141 {
 3142         struct xvfsconf xvfsp;
 3143 
 3144         bzero(&xvfsp, sizeof(xvfsp));
 3145         strcpy(xvfsp.vfc_name, vfsp->vfc_name);
 3146         xvfsp.vfc_typenum = vfsp->vfc_typenum;
 3147         xvfsp.vfc_refcount = vfsp->vfc_refcount;
 3148         xvfsp.vfc_flags = vfsp->vfc_flags;
 3149         /*
 3150          * These are unused in userland, we keep them
 3151          * to not break binary compatibility.
 3152          */
 3153         xvfsp.vfc_vfsops = NULL;
 3154         xvfsp.vfc_next = NULL;
 3155         return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 3156 }
 3157 
 3158 #ifdef COMPAT_FREEBSD32
 3159 struct xvfsconf32 {
 3160         uint32_t        vfc_vfsops;
 3161         char            vfc_name[MFSNAMELEN];
 3162         int32_t         vfc_typenum;
 3163         int32_t         vfc_refcount;
 3164         int32_t         vfc_flags;
 3165         uint32_t        vfc_next;
 3166 };
 3167 
 3168 static int
 3169 vfsconf2x32(struct sysctl_req *req, struct vfsconf *vfsp)
 3170 {
 3171         struct xvfsconf32 xvfsp;
 3172 
 3173         strcpy(xvfsp.vfc_name, vfsp->vfc_name);
 3174         xvfsp.vfc_typenum = vfsp->vfc_typenum;
 3175         xvfsp.vfc_refcount = vfsp->vfc_refcount;
 3176         xvfsp.vfc_flags = vfsp->vfc_flags;
 3177         xvfsp.vfc_vfsops = 0;
 3178         xvfsp.vfc_next = 0;
 3179         return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 3180 }
 3181 #endif
 3182 
 3183 /*
 3184  * Top level filesystem related information gathering.
 3185  */
 3186 static int
 3187 sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
 3188 {
 3189         struct vfsconf *vfsp;
 3190         int error;
 3191 
 3192         error = 0;
 3193         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3194 #ifdef COMPAT_FREEBSD32
 3195                 if (req->flags & SCTL_MASK32)
 3196                         error = vfsconf2x32(req, vfsp);
 3197                 else
 3198 #endif
 3199                         error = vfsconf2x(req, vfsp);
 3200                 if (error)
 3201                         break;
 3202         }
 3203         return (error);
 3204 }
 3205 
 3206 SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLTYPE_OPAQUE | CTLFLAG_RD,
 3207     NULL, 0, sysctl_vfs_conflist,
 3208     "S,xvfsconf", "List of all configured filesystems");
 3209 
 3210 #ifndef BURN_BRIDGES
 3211 static int      sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
 3212 
 3213 static int
 3214 vfs_sysctl(SYSCTL_HANDLER_ARGS)
 3215 {
 3216         int *name = (int *)arg1 - 1;    /* XXX */
 3217         u_int namelen = arg2 + 1;       /* XXX */
 3218         struct vfsconf *vfsp;
 3219 
 3220         log(LOG_WARNING, "userland calling deprecated sysctl, "
 3221             "please rebuild world\n");
 3222 
 3223 #if 1 || defined(COMPAT_PRELITE2)
 3224         /* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
 3225         if (namelen == 1)
 3226                 return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
 3227 #endif
 3228 
 3229         switch (name[1]) {
 3230         case VFS_MAXTYPENUM:
 3231                 if (namelen != 2)
 3232                         return (ENOTDIR);
 3233                 return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
 3234         case VFS_CONF:
 3235                 if (namelen != 3)
 3236                         return (ENOTDIR);       /* overloaded */
 3237                 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
 3238                         if (vfsp->vfc_typenum == name[2])
 3239                                 break;
 3240                 if (vfsp == NULL)
 3241                         return (EOPNOTSUPP);
 3242 #ifdef COMPAT_FREEBSD32
 3243                 if (req->flags & SCTL_MASK32)
 3244                         return (vfsconf2x32(req, vfsp));
 3245                 else
 3246 #endif
 3247                         return (vfsconf2x(req, vfsp));
 3248         }
 3249         return (EOPNOTSUPP);
 3250 }
 3251 
 3252 static SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP,
 3253     vfs_sysctl, "Generic filesystem");
 3254 
 3255 #if 1 || defined(COMPAT_PRELITE2)
 3256 
 3257 static int
 3258 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
 3259 {
 3260         int error;
 3261         struct vfsconf *vfsp;
 3262         struct ovfsconf ovfs;
 3263 
 3264         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3265                 bzero(&ovfs, sizeof(ovfs));
 3266                 ovfs.vfc_vfsops = vfsp->vfc_vfsops;     /* XXX used as flag */
 3267                 strcpy(ovfs.vfc_name, vfsp->vfc_name);
 3268                 ovfs.vfc_index = vfsp->vfc_typenum;
 3269                 ovfs.vfc_refcount = vfsp->vfc_refcount;
 3270                 ovfs.vfc_flags = vfsp->vfc_flags;
 3271                 error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
 3272                 if (error)
 3273                         return error;
 3274         }
 3275         return 0;
 3276 }
 3277 
 3278 #endif /* 1 || COMPAT_PRELITE2 */
 3279 #endif /* !BURN_BRIDGES */
 3280 
 3281 #define KINFO_VNODESLOP         10
 3282 #ifdef notyet
 3283 /*
 3284  * Dump vnode list (via sysctl).
 3285  */
 3286 /* ARGSUSED */
 3287 static int
 3288 sysctl_vnode(SYSCTL_HANDLER_ARGS)
 3289 {
 3290         struct xvnode *xvn;
 3291         struct mount *mp;
 3292         struct vnode *vp;
 3293         int error, len, n;
 3294 
 3295         /*
 3296          * Stale numvnodes access is not fatal here.
 3297          */
 3298         req->lock = 0;
 3299         len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
 3300         if (!req->oldptr)
 3301                 /* Make an estimate */
 3302                 return (SYSCTL_OUT(req, 0, len));
 3303 
 3304         error = sysctl_wire_old_buffer(req, 0);
 3305         if (error != 0)
 3306                 return (error);
 3307         xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
 3308         n = 0;
 3309         mtx_lock(&mountlist_mtx);
 3310         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 3311                 if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
 3312                         continue;
 3313                 MNT_ILOCK(mp);
 3314                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3315                         if (n == len)
 3316                                 break;
 3317                         vref(vp);
 3318                         xvn[n].xv_size = sizeof *xvn;
 3319                         xvn[n].xv_vnode = vp;
 3320                         xvn[n].xv_id = 0;       /* XXX compat */
 3321 #define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
 3322                         XV_COPY(usecount);
 3323                         XV_COPY(writecount);
 3324                         XV_COPY(holdcnt);
 3325                         XV_COPY(mount);
 3326                         XV_COPY(numoutput);
 3327                         XV_COPY(type);
 3328 #undef XV_COPY
 3329                         xvn[n].xv_flag = vp->v_vflag;
 3330 
 3331                         switch (vp->v_type) {
 3332                         case VREG:
 3333                         case VDIR:
 3334                         case VLNK:
 3335                                 break;
 3336                         case VBLK:
 3337                         case VCHR:
 3338                                 if (vp->v_rdev == NULL) {
 3339                                         vrele(vp);
 3340                                         continue;
 3341                                 }
 3342                                 xvn[n].xv_dev = dev2udev(vp->v_rdev);
 3343                                 break;
 3344                         case VSOCK:
 3345                                 xvn[n].xv_socket = vp->v_socket;
 3346                                 break;
 3347                         case VFIFO:
 3348                                 xvn[n].xv_fifo = vp->v_fifoinfo;
 3349                                 break;
 3350                         case VNON:
 3351                         case VBAD:
 3352                         default:
 3353                                 /* shouldn't happen? */
 3354                                 vrele(vp);
 3355                                 continue;
 3356                         }
 3357                         vrele(vp);
 3358                         ++n;
 3359                 }
 3360                 MNT_IUNLOCK(mp);
 3361                 mtx_lock(&mountlist_mtx);
 3362                 vfs_unbusy(mp);
 3363                 if (n == len)
 3364                         break;
 3365         }
 3366         mtx_unlock(&mountlist_mtx);
 3367 
 3368         error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
 3369         free(xvn, M_TEMP);
 3370         return (error);
 3371 }
 3372 
 3373 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
 3374     0, 0, sysctl_vnode, "S,xvnode", "");
 3375 #endif
 3376 
 3377 /*
 3378  * Unmount all filesystems. The list is traversed in reverse order
 3379  * of mounting to avoid dependencies.
 3380  */
 3381 void
 3382 vfs_unmountall(void)
 3383 {
 3384         struct mount *mp;
 3385         struct thread *td;
 3386         int error;
 3387 
 3388         CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__);
 3389         td = curthread;
 3390 
 3391         /*
 3392          * Since this only runs when rebooting, it is not interlocked.
 3393          */
 3394         while(!TAILQ_EMPTY(&mountlist)) {
 3395                 mp = TAILQ_LAST(&mountlist, mntlist);
 3396                 error = dounmount(mp, MNT_FORCE, td);
 3397                 if (error) {
 3398                         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 3399                         /*
 3400                          * XXX: Due to the way in which we mount the root
 3401                          * file system off of devfs, devfs will generate a
 3402                          * "busy" warning when we try to unmount it before
 3403                          * the root.  Don't print a warning as a result in
 3404                          * order to avoid false positive errors that may
 3405                          * cause needless upset.
 3406                          */
 3407                         if (strcmp(mp->mnt_vfc->vfc_name, "devfs") != 0) {
 3408                                 printf("unmount of %s failed (",
 3409                                     mp->mnt_stat.f_mntonname);
 3410                                 if (error == EBUSY)
 3411                                         printf("BUSY)\n");
 3412                                 else
 3413                                         printf("%d)\n", error);
 3414                         }
 3415                 } else {
 3416                         /* The unmount has removed mp from the mountlist */
 3417                 }
 3418         }
 3419 }
 3420 
 3421 /*
 3422  * perform msync on all vnodes under a mount point
 3423  * the mount point must be locked.
 3424  */
 3425 void
 3426 vfs_msync(struct mount *mp, int flags)
 3427 {
 3428         struct vnode *vp, *mvp;
 3429         struct vm_object *obj;
 3430 
 3431         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
 3432         MNT_VNODE_FOREACH_ACTIVE(vp, mp, mvp) {
 3433                 obj = vp->v_object;
 3434                 if (obj != NULL && (obj->flags & OBJ_MIGHTBEDIRTY) != 0 &&
 3435                     (flags == MNT_WAIT || VOP_ISLOCKED(vp) == 0)) {
 3436                         if (!vget(vp,
 3437                             LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
 3438                             curthread)) {
 3439                                 if (vp->v_vflag & VV_NOSYNC) {  /* unlinked */
 3440                                         vput(vp);
 3441                                         continue;
 3442                                 }
 3443 
 3444                                 obj = vp->v_object;
 3445                                 if (obj != NULL) {
 3446                                         VM_OBJECT_WLOCK(obj);
 3447                                         vm_object_page_clean(obj, 0, 0,
 3448                                             flags == MNT_WAIT ?
 3449                                             OBJPC_SYNC : OBJPC_NOSYNC);
 3450                                         VM_OBJECT_WUNLOCK(obj);
 3451                                 }
 3452                                 vput(vp);
 3453                         }
 3454                 } else
 3455                         VI_UNLOCK(vp);
 3456         }
 3457 }
 3458 
 3459 static void
 3460 destroy_vpollinfo_free(struct vpollinfo *vi)
 3461 {
 3462 
 3463         knlist_destroy(&vi->vpi_selinfo.si_note);
 3464         mtx_destroy(&vi->vpi_lock);
 3465         uma_zfree(vnodepoll_zone, vi);
 3466 }
 3467 
 3468 static void
 3469 destroy_vpollinfo(struct vpollinfo *vi)
 3470 {
 3471 
 3472         knlist_clear(&vi->vpi_selinfo.si_note, 1);
 3473         seldrain(&vi->vpi_selinfo);
 3474         destroy_vpollinfo_free(vi);
 3475 }
 3476 
 3477 /*
 3478  * Initalize per-vnode helper structure to hold poll-related state.
 3479  */
 3480 void
 3481 v_addpollinfo(struct vnode *vp)
 3482 {
 3483         struct vpollinfo *vi;
 3484 
 3485         if (vp->v_pollinfo != NULL)
 3486                 return;
 3487         vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
 3488         mtx_init(&vi->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
 3489         knlist_init(&vi->vpi_selinfo.si_note, vp, vfs_knllock,
 3490             vfs_knlunlock, vfs_knl_assert_locked, vfs_knl_assert_unlocked);
 3491         VI_LOCK(vp);
 3492         if (vp->v_pollinfo != NULL) {
 3493                 VI_UNLOCK(vp);
 3494                 destroy_vpollinfo_free(vi);
 3495                 return;
 3496         }
 3497         vp->v_pollinfo = vi;
 3498         VI_UNLOCK(vp);
 3499 }
 3500 
 3501 /*
 3502  * Record a process's interest in events which might happen to
 3503  * a vnode.  Because poll uses the historic select-style interface
 3504  * internally, this routine serves as both the ``check for any
 3505  * pending events'' and the ``record my interest in future events''
 3506  * functions.  (These are done together, while the lock is held,
 3507  * to avoid race conditions.)
 3508  */
 3509 int
 3510 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
 3511 {
 3512 
 3513         v_addpollinfo(vp);
 3514         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3515         if (vp->v_pollinfo->vpi_revents & events) {
 3516                 /*
 3517                  * This leaves events we are not interested
 3518                  * in available for the other process which
 3519                  * which presumably had requested them
 3520                  * (otherwise they would never have been
 3521                  * recorded).
 3522                  */
 3523                 events &= vp->v_pollinfo->vpi_revents;
 3524                 vp->v_pollinfo->vpi_revents &= ~events;
 3525 
 3526                 mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3527                 return (events);
 3528         }
 3529         vp->v_pollinfo->vpi_events |= events;
 3530         selrecord(td, &vp->v_pollinfo->vpi_selinfo);
 3531         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3532         return (0);
 3533 }
 3534 
 3535 /*
 3536  * Routine to create and manage a filesystem syncer vnode.
 3537  */
 3538 #define sync_close ((int (*)(struct  vop_close_args *))nullop)
 3539 static int      sync_fsync(struct  vop_fsync_args *);
 3540 static int      sync_inactive(struct  vop_inactive_args *);
 3541 static int      sync_reclaim(struct  vop_reclaim_args *);
 3542 
 3543 static struct vop_vector sync_vnodeops = {
 3544         .vop_bypass =   VOP_EOPNOTSUPP,
 3545         .vop_close =    sync_close,             /* close */
 3546         .vop_fsync =    sync_fsync,             /* fsync */
 3547         .vop_inactive = sync_inactive,  /* inactive */
 3548         .vop_reclaim =  sync_reclaim,   /* reclaim */
 3549         .vop_lock1 =    vop_stdlock,    /* lock */
 3550         .vop_unlock =   vop_stdunlock,  /* unlock */
 3551         .vop_islocked = vop_stdislocked,        /* islocked */
 3552 };
 3553 
 3554 /*
 3555  * Create a new filesystem syncer vnode for the specified mount point.
 3556  */
 3557 void
 3558 vfs_allocate_syncvnode(struct mount *mp)
 3559 {
 3560         struct vnode *vp;
 3561         struct bufobj *bo;
 3562         static long start, incr, next;
 3563         int error;
 3564 
 3565         /* Allocate a new vnode */
 3566         error = getnewvnode("syncer", mp, &sync_vnodeops, &vp);
 3567         if (error != 0)
 3568                 panic("vfs_allocate_syncvnode: getnewvnode() failed");
 3569         vp->v_type = VNON;
 3570         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3571         vp->v_vflag |= VV_FORCEINSMQ;
 3572         error = insmntque(vp, mp);
 3573         if (error != 0)
 3574                 panic("vfs_allocate_syncvnode: insmntque() failed");
 3575         vp->v_vflag &= ~VV_FORCEINSMQ;
 3576         VOP_UNLOCK(vp, 0);
 3577         /*
 3578          * Place the vnode onto the syncer worklist. We attempt to
 3579          * scatter them about on the list so that they will go off
 3580          * at evenly distributed times even if all the filesystems
 3581          * are mounted at once.
 3582          */
 3583         next += incr;
 3584         if (next == 0 || next > syncer_maxdelay) {
 3585                 start /= 2;
 3586                 incr /= 2;
 3587                 if (start == 0) {
 3588                         start = syncer_maxdelay / 2;
 3589                         incr = syncer_maxdelay;
 3590                 }
 3591                 next = start;
 3592         }
 3593         bo = &vp->v_bufobj;
 3594         BO_LOCK(bo);
 3595         vn_syncer_add_to_worklist(bo, syncdelay > 0 ? next % syncdelay : 0);
 3596         /* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
 3597         mtx_lock(&sync_mtx);
 3598         sync_vnode_count++;
 3599         if (mp->mnt_syncer == NULL) {
 3600                 mp->mnt_syncer = vp;
 3601                 vp = NULL;
 3602         }
 3603         mtx_unlock(&sync_mtx);
 3604         BO_UNLOCK(bo);
 3605         if (vp != NULL) {
 3606                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3607                 vgone(vp);
 3608                 vput(vp);
 3609         }
 3610 }
 3611 
 3612 void
 3613 vfs_deallocate_syncvnode(struct mount *mp)
 3614 {
 3615         struct vnode *vp;
 3616 
 3617         mtx_lock(&sync_mtx);
 3618         vp = mp->mnt_syncer;
 3619         if (vp != NULL)
 3620                 mp->mnt_syncer = NULL;
 3621         mtx_unlock(&sync_mtx);
 3622         if (vp != NULL)
 3623                 vrele(vp);
 3624 }
 3625 
 3626 /*
 3627  * Do a lazy sync of the filesystem.
 3628  */
 3629 static int
 3630 sync_fsync(struct vop_fsync_args *ap)
 3631 {
 3632         struct vnode *syncvp = ap->a_vp;
 3633         struct mount *mp = syncvp->v_mount;
 3634         int error, save;
 3635         struct bufobj *bo;
 3636 
 3637         /*
 3638          * We only need to do something if this is a lazy evaluation.
 3639          */
 3640         if (ap->a_waitfor != MNT_LAZY)
 3641                 return (0);
 3642 
 3643         /*
 3644          * Move ourselves to the back of the sync list.
 3645          */
 3646         bo = &syncvp->v_bufobj;
 3647         BO_LOCK(bo);
 3648         vn_syncer_add_to_worklist(bo, syncdelay);
 3649         BO_UNLOCK(bo);
 3650 
 3651         /*
 3652          * Walk the list of vnodes pushing all that are dirty and
 3653          * not already on the sync list.
 3654          */
 3655         mtx_lock(&mountlist_mtx);
 3656         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK) != 0) {
 3657                 mtx_unlock(&mountlist_mtx);
 3658                 return (0);
 3659         }
 3660         if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
 3661                 vfs_unbusy(mp);
 3662                 return (0);
 3663         }
 3664         save = curthread_pflags_set(TDP_SYNCIO);
 3665         vfs_msync(mp, MNT_NOWAIT);
 3666         error = VFS_SYNC(mp, MNT_LAZY);
 3667         curthread_pflags_restore(save);
 3668         vn_finished_write(mp);
 3669         vfs_unbusy(mp);
 3670         return (error);
 3671 }
 3672 
 3673 /*
 3674  * The syncer vnode is no referenced.
 3675  */
 3676 static int
 3677 sync_inactive(struct vop_inactive_args *ap)
 3678 {
 3679 
 3680         vgone(ap->a_vp);
 3681         return (0);
 3682 }
 3683 
 3684 /*
 3685  * The syncer vnode is no longer needed and is being decommissioned.
 3686  *
 3687  * Modifications to the worklist must be protected by sync_mtx.
 3688  */
 3689 static int
 3690 sync_reclaim(struct vop_reclaim_args *ap)
 3691 {
 3692         struct vnode *vp = ap->a_vp;
 3693         struct bufobj *bo;
 3694 
 3695         bo = &vp->v_bufobj;
 3696         BO_LOCK(bo);
 3697         mtx_lock(&sync_mtx);
 3698         if (vp->v_mount->mnt_syncer == vp)
 3699                 vp->v_mount->mnt_syncer = NULL;
 3700         if (bo->bo_flag & BO_ONWORKLST) {
 3701                 LIST_REMOVE(bo, bo_synclist);
 3702                 syncer_worklist_len--;
 3703                 sync_vnode_count--;
 3704                 bo->bo_flag &= ~BO_ONWORKLST;
 3705         }
 3706         mtx_unlock(&sync_mtx);
 3707         BO_UNLOCK(bo);
 3708 
 3709         return (0);
 3710 }
 3711 
 3712 /*
 3713  * Check if vnode represents a disk device
 3714  */
 3715 int
 3716 vn_isdisk(struct vnode *vp, int *errp)
 3717 {
 3718         int error;
 3719 
 3720         error = 0;
 3721         dev_lock();
 3722         if (vp->v_type != VCHR)
 3723                 error = ENOTBLK;
 3724         else if (vp->v_rdev == NULL)
 3725                 error = ENXIO;
 3726         else if (vp->v_rdev->si_devsw == NULL)
 3727                 error = ENXIO;
 3728         else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
 3729                 error = ENOTBLK;
 3730         dev_unlock();
 3731         if (errp != NULL)
 3732                 *errp = error;
 3733         return (error == 0);
 3734 }
 3735 
 3736 /*
 3737  * Common filesystem object access control check routine.  Accepts a
 3738  * vnode's type, "mode", uid and gid, requested access mode, credentials,
 3739  * and optional call-by-reference privused argument allowing vaccess()
 3740  * to indicate to the caller whether privilege was used to satisfy the
 3741  * request (obsoleted).  Returns 0 on success, or an errno on failure.
 3742  */
 3743 int
 3744 vaccess(enum vtype type, mode_t file_mode, uid_t file_uid, gid_t file_gid,
 3745     accmode_t accmode, struct ucred *cred, int *privused)
 3746 {
 3747         accmode_t dac_granted;
 3748         accmode_t priv_granted;
 3749 
 3750         KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND)) == 0,
 3751             ("invalid bit in accmode"));
 3752         KASSERT((accmode & VAPPEND) == 0 || (accmode & VWRITE),
 3753             ("VAPPEND without VWRITE"));
 3754 
 3755         /*
 3756          * Look for a normal, non-privileged way to access the file/directory
 3757          * as requested.  If it exists, go with that.
 3758          */
 3759 
 3760         if (privused != NULL)
 3761                 *privused = 0;
 3762 
 3763         dac_granted = 0;
 3764 
 3765         /* Check the owner. */
 3766         if (cred->cr_uid == file_uid) {
 3767                 dac_granted |= VADMIN;
 3768                 if (file_mode & S_IXUSR)
 3769                         dac_granted |= VEXEC;
 3770                 if (file_mode & S_IRUSR)
 3771                         dac_granted |= VREAD;
 3772                 if (file_mode & S_IWUSR)
 3773                         dac_granted |= (VWRITE | VAPPEND);
 3774 
 3775                 if ((accmode & dac_granted) == accmode)
 3776                         return (0);
 3777 
 3778                 goto privcheck;
 3779         }
 3780 
 3781         /* Otherwise, check the groups (first match) */
 3782         if (groupmember(file_gid, cred)) {
 3783                 if (file_mode & S_IXGRP)
 3784                         dac_granted |= VEXEC;
 3785                 if (file_mode & S_IRGRP)
 3786                         dac_granted |= VREAD;
 3787                 if (file_mode & S_IWGRP)
 3788                         dac_granted |= (VWRITE | VAPPEND);
 3789 
 3790                 if ((accmode & dac_granted) == accmode)
 3791                         return (0);
 3792 
 3793                 goto privcheck;
 3794         }
 3795 
 3796         /* Otherwise, check everyone else. */
 3797         if (file_mode & S_IXOTH)
 3798                 dac_granted |= VEXEC;
 3799         if (file_mode & S_IROTH)
 3800                 dac_granted |= VREAD;
 3801         if (file_mode & S_IWOTH)
 3802                 dac_granted |= (VWRITE | VAPPEND);
 3803         if ((accmode & dac_granted) == accmode)
 3804                 return (0);
 3805 
 3806 privcheck:
 3807         /*
 3808          * Build a privilege mask to determine if the set of privileges
 3809          * satisfies the requirements when combined with the granted mask
 3810          * from above.  For each privilege, if the privilege is required,
 3811          * bitwise or the request type onto the priv_granted mask.
 3812          */
 3813         priv_granted = 0;
 3814 
 3815         if (type == VDIR) {
 3816                 /*
 3817                  * For directories, use PRIV_VFS_LOOKUP to satisfy VEXEC
 3818                  * requests, instead of PRIV_VFS_EXEC.
 3819                  */
 3820                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3821                     !priv_check_cred(cred, PRIV_VFS_LOOKUP, 0))
 3822                         priv_granted |= VEXEC;
 3823         } else {
 3824                 /*
 3825                  * Ensure that at least one execute bit is on. Otherwise,
 3826                  * a privileged user will always succeed, and we don't want
 3827                  * this to happen unless the file really is executable.
 3828                  */
 3829                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3830                     (file_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0 &&
 3831                     !priv_check_cred(cred, PRIV_VFS_EXEC, 0))
 3832                         priv_granted |= VEXEC;
 3833         }
 3834 
 3835         if ((accmode & VREAD) && ((dac_granted & VREAD) == 0) &&
 3836             !priv_check_cred(cred, PRIV_VFS_READ, 0))
 3837                 priv_granted |= VREAD;
 3838 
 3839         if ((accmode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
 3840             !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
 3841                 priv_granted |= (VWRITE | VAPPEND);
 3842 
 3843         if ((accmode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
 3844             !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
 3845                 priv_granted |= VADMIN;
 3846 
 3847         if ((accmode & (priv_granted | dac_granted)) == accmode) {
 3848                 /* XXX audit: privilege used */
 3849                 if (privused != NULL)
 3850                         *privused = 1;
 3851                 return (0);
 3852         }
 3853 
 3854         return ((accmode & VADMIN) ? EPERM : EACCES);
 3855 }
 3856 
 3857 /*
 3858  * Credential check based on process requesting service, and per-attribute
 3859  * permissions.
 3860  */
 3861 int
 3862 extattr_check_cred(struct vnode *vp, int attrnamespace, struct ucred *cred,
 3863     struct thread *td, accmode_t accmode)
 3864 {
 3865 
 3866         /*
 3867          * Kernel-invoked always succeeds.
 3868          */
 3869         if (cred == NOCRED)
 3870                 return (0);
 3871 
 3872         /*
 3873          * Do not allow privileged processes in jail to directly manipulate
 3874          * system attributes.
 3875          */
 3876         switch (attrnamespace) {
 3877         case EXTATTR_NAMESPACE_SYSTEM:
 3878                 /* Potentially should be: return (EPERM); */
 3879                 return (priv_check_cred(cred, PRIV_VFS_EXTATTR_SYSTEM, 0));
 3880         case EXTATTR_NAMESPACE_USER:
 3881                 return (VOP_ACCESS(vp, accmode, cred, td));
 3882         default:
 3883                 return (EPERM);
 3884         }
 3885 }
 3886 
 3887 #ifdef DEBUG_VFS_LOCKS
 3888 /*
 3889  * This only exists to supress warnings from unlocked specfs accesses.  It is
 3890  * no longer ok to have an unlocked VFS.
 3891  */
 3892 #define IGNORE_LOCK(vp) (panicstr != NULL || (vp) == NULL ||            \
 3893         (vp)->v_type == VCHR || (vp)->v_type == VBAD)
 3894 
 3895 int vfs_badlock_ddb = 1;        /* Drop into debugger on violation. */
 3896 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0,
 3897     "Drop into debugger on lock violation");
 3898 
 3899 int vfs_badlock_mutex = 1;      /* Check for interlock across VOPs. */
 3900 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex,
 3901     0, "Check for interlock across VOPs");
 3902 
 3903 int vfs_badlock_print = 1;      /* Print lock violations. */
 3904 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print,
 3905     0, "Print lock violations");
 3906 
 3907 #ifdef KDB
 3908 int vfs_badlock_backtrace = 1;  /* Print backtrace at lock violations. */
 3909 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW,
 3910     &vfs_badlock_backtrace, 0, "Print backtrace at lock violations");
 3911 #endif
 3912 
 3913 static void
 3914 vfs_badlock(const char *msg, const char *str, struct vnode *vp)
 3915 {
 3916 
 3917 #ifdef KDB
 3918         if (vfs_badlock_backtrace)
 3919                 kdb_backtrace();
 3920 #endif
 3921         if (vfs_badlock_print)
 3922                 printf("%s: %p %s\n", str, (void *)vp, msg);
 3923         if (vfs_badlock_ddb)
 3924                 kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3925 }
 3926 
 3927 void
 3928 assert_vi_locked(struct vnode *vp, const char *str)
 3929 {
 3930 
 3931         if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
 3932                 vfs_badlock("interlock is not locked but should be", str, vp);
 3933 }
 3934 
 3935 void
 3936 assert_vi_unlocked(struct vnode *vp, const char *str)
 3937 {
 3938 
 3939         if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
 3940                 vfs_badlock("interlock is locked but should not be", str, vp);
 3941 }
 3942 
 3943 void
 3944 assert_vop_locked(struct vnode *vp, const char *str)
 3945 {
 3946         int locked;
 3947 
 3948         if (!IGNORE_LOCK(vp)) {
 3949                 locked = VOP_ISLOCKED(vp);
 3950                 if (locked == 0 || locked == LK_EXCLOTHER)
 3951                         vfs_badlock("is not locked but should be", str, vp);
 3952         }
 3953 }
 3954 
 3955 void
 3956 assert_vop_unlocked(struct vnode *vp, const char *str)
 3957 {
 3958 
 3959         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
 3960                 vfs_badlock("is locked but should not be", str, vp);
 3961 }
 3962 
 3963 void
 3964 assert_vop_elocked(struct vnode *vp, const char *str)
 3965 {
 3966 
 3967         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 3968                 vfs_badlock("is not exclusive locked but should be", str, vp);
 3969 }
 3970 
 3971 #if 0
 3972 void
 3973 assert_vop_elocked_other(struct vnode *vp, const char *str)
 3974 {
 3975 
 3976         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLOTHER)
 3977                 vfs_badlock("is not exclusive locked by another thread",
 3978                     str, vp);
 3979 }
 3980 
 3981 void
 3982 assert_vop_slocked(struct vnode *vp, const char *str)
 3983 {
 3984 
 3985         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_SHARED)
 3986                 vfs_badlock("is not locked shared but should be", str, vp);
 3987 }
 3988 #endif /* 0 */
 3989 #endif /* DEBUG_VFS_LOCKS */
 3990 
 3991 void
 3992 vop_rename_fail(struct vop_rename_args *ap)
 3993 {
 3994 
 3995         if (ap->a_tvp != NULL)
 3996                 vput(ap->a_tvp);
 3997         if (ap->a_tdvp == ap->a_tvp)
 3998                 vrele(ap->a_tdvp);
 3999         else
 4000                 vput(ap->a_tdvp);
 4001         vrele(ap->a_fdvp);
 4002         vrele(ap->a_fvp);
 4003 }
 4004 
 4005 void
 4006 vop_rename_pre(void *ap)
 4007 {
 4008         struct vop_rename_args *a = ap;
 4009 
 4010 #ifdef DEBUG_VFS_LOCKS
 4011         if (a->a_tvp)
 4012                 ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
 4013         ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
 4014         ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
 4015         ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
 4016 
 4017         /* Check the source (from). */
 4018         if (a->a_tdvp->v_vnlock != a->a_fdvp->v_vnlock &&
 4019             (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fdvp->v_vnlock))
 4020                 ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
 4021         if (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fvp->v_vnlock)
 4022                 ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: fvp locked");
 4023 
 4024         /* Check the target. */
 4025         if (a->a_tvp)
 4026                 ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
 4027         ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
 4028 #endif
 4029         if (a->a_tdvp != a->a_fdvp)
 4030                 vhold(a->a_fdvp);
 4031         if (a->a_tvp != a->a_fvp)
 4032                 vhold(a->a_fvp);
 4033         vhold(a->a_tdvp);
 4034         if (a->a_tvp)
 4035                 vhold(a->a_tvp);
 4036 }
 4037 
 4038 void
 4039 vop_strategy_pre(void *ap)
 4040 {
 4041 #ifdef DEBUG_VFS_LOCKS
 4042         struct vop_strategy_args *a;
 4043         struct buf *bp;
 4044 
 4045         a = ap;
 4046         bp = a->a_bp;
 4047 
 4048         /*
 4049          * Cluster ops lock their component buffers but not the IO container.
 4050          */
 4051         if ((bp->b_flags & B_CLUSTER) != 0)
 4052                 return;
 4053 
 4054         if (panicstr == NULL && !BUF_ISLOCKED(bp)) {
 4055                 if (vfs_badlock_print)
 4056                         printf(
 4057                             "VOP_STRATEGY: bp is not locked but should be\n");
 4058                 if (vfs_badlock_ddb)
 4059                         kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 4060         }
 4061 #endif
 4062 }
 4063 
 4064 void
 4065 vop_lock_pre(void *ap)
 4066 {
 4067 #ifdef DEBUG_VFS_LOCKS
 4068         struct vop_lock1_args *a = ap;
 4069 
 4070         if ((a->a_flags & LK_INTERLOCK) == 0)
 4071                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 4072         else
 4073                 ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
 4074 #endif
 4075 }
 4076 
 4077 void
 4078 vop_lock_post(void *ap, int rc)
 4079 {
 4080 #ifdef DEBUG_VFS_LOCKS
 4081         struct vop_lock1_args *a = ap;
 4082 
 4083         ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 4084         if (rc == 0 && (a->a_flags & LK_EXCLOTHER) == 0)
 4085                 ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
 4086 #endif
 4087 }
 4088 
 4089 void
 4090 vop_unlock_pre(void *ap)
 4091 {
 4092 #ifdef DEBUG_VFS_LOCKS
 4093         struct vop_unlock_args *a = ap;
 4094 
 4095         if (a->a_flags & LK_INTERLOCK)
 4096                 ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
 4097         ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
 4098 #endif
 4099 }
 4100 
 4101 void
 4102 vop_unlock_post(void *ap, int rc)
 4103 {
 4104 #ifdef DEBUG_VFS_LOCKS
 4105         struct vop_unlock_args *a = ap;
 4106 
 4107         if (a->a_flags & LK_INTERLOCK)
 4108                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
 4109 #endif
 4110 }
 4111 
 4112 void
 4113 vop_create_post(void *ap, int rc)
 4114 {
 4115         struct vop_create_args *a = ap;
 4116 
 4117         if (!rc)
 4118                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4119 }
 4120 
 4121 void
 4122 vop_deleteextattr_post(void *ap, int rc)
 4123 {
 4124         struct vop_deleteextattr_args *a = ap;
 4125 
 4126         if (!rc)
 4127                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4128 }
 4129 
 4130 void
 4131 vop_link_post(void *ap, int rc)
 4132 {
 4133         struct vop_link_args *a = ap;
 4134 
 4135         if (!rc) {
 4136                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_LINK);
 4137                 VFS_KNOTE_LOCKED(a->a_tdvp, NOTE_WRITE);
 4138         }
 4139 }
 4140 
 4141 void
 4142 vop_mkdir_post(void *ap, int rc)
 4143 {
 4144         struct vop_mkdir_args *a = ap;
 4145 
 4146         if (!rc)
 4147                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4148 }
 4149 
 4150 void
 4151 vop_mknod_post(void *ap, int rc)
 4152 {
 4153         struct vop_mknod_args *a = ap;
 4154 
 4155         if (!rc)
 4156                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4157 }
 4158 
 4159 void
 4160 vop_remove_post(void *ap, int rc)
 4161 {
 4162         struct vop_remove_args *a = ap;
 4163 
 4164         if (!rc) {
 4165                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4166                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4167         }
 4168 }
 4169 
 4170 void
 4171 vop_rename_post(void *ap, int rc)
 4172 {
 4173         struct vop_rename_args *a = ap;
 4174 
 4175         if (!rc) {
 4176                 VFS_KNOTE_UNLOCKED(a->a_fdvp, NOTE_WRITE);
 4177                 VFS_KNOTE_UNLOCKED(a->a_tdvp, NOTE_WRITE);
 4178                 VFS_KNOTE_UNLOCKED(a->a_fvp, NOTE_RENAME);
 4179                 if (a->a_tvp)
 4180                         VFS_KNOTE_UNLOCKED(a->a_tvp, NOTE_DELETE);
 4181         }
 4182         if (a->a_tdvp != a->a_fdvp)
 4183                 vdrop(a->a_fdvp);
 4184         if (a->a_tvp != a->a_fvp)
 4185                 vdrop(a->a_fvp);
 4186         vdrop(a->a_tdvp);
 4187         if (a->a_tvp)
 4188                 vdrop(a->a_tvp);
 4189 }
 4190 
 4191 void
 4192 vop_rmdir_post(void *ap, int rc)
 4193 {
 4194         struct vop_rmdir_args *a = ap;
 4195 
 4196         if (!rc) {
 4197                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4198                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4199         }
 4200 }
 4201 
 4202 void
 4203 vop_setattr_post(void *ap, int rc)
 4204 {
 4205         struct vop_setattr_args *a = ap;
 4206 
 4207         if (!rc)
 4208                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4209 }
 4210 
 4211 void
 4212 vop_setextattr_post(void *ap, int rc)
 4213 {
 4214         struct vop_setextattr_args *a = ap;
 4215 
 4216         if (!rc)
 4217                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4218 }
 4219 
 4220 void
 4221 vop_symlink_post(void *ap, int rc)
 4222 {
 4223         struct vop_symlink_args *a = ap;
 4224 
 4225         if (!rc)
 4226                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4227 }
 4228 
 4229 static struct knlist fs_knlist;
 4230 
 4231 static void
 4232 vfs_event_init(void *arg)
 4233 {
 4234         knlist_init_mtx(&fs_knlist, NULL);
 4235 }
 4236 /* XXX - correct order? */
 4237 SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
 4238 
 4239 void
 4240 vfs_event_signal(fsid_t *fsid, uint32_t event, intptr_t data __unused)
 4241 {
 4242 
 4243         KNOTE_UNLOCKED(&fs_knlist, event);
 4244 }
 4245 
 4246 static int      filt_fsattach(struct knote *kn);
 4247 static void     filt_fsdetach(struct knote *kn);
 4248 static int      filt_fsevent(struct knote *kn, long hint);
 4249 
 4250 struct filterops fs_filtops = {
 4251         .f_isfd = 0,
 4252         .f_attach = filt_fsattach,
 4253         .f_detach = filt_fsdetach,
 4254         .f_event = filt_fsevent
 4255 };
 4256 
 4257 static int
 4258 filt_fsattach(struct knote *kn)
 4259 {
 4260 
 4261         kn->kn_flags |= EV_CLEAR;
 4262         knlist_add(&fs_knlist, kn, 0);
 4263         return (0);
 4264 }
 4265 
 4266 static void
 4267 filt_fsdetach(struct knote *kn)
 4268 {
 4269 
 4270         knlist_remove(&fs_knlist, kn, 0);
 4271 }
 4272 
 4273 static int
 4274 filt_fsevent(struct knote *kn, long hint)
 4275 {
 4276 
 4277         kn->kn_fflags |= hint;
 4278         return (kn->kn_fflags != 0);
 4279 }
 4280 
 4281 static int
 4282 sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
 4283 {
 4284         struct vfsidctl vc;
 4285         int error;
 4286         struct mount *mp;
 4287 
 4288         error = SYSCTL_IN(req, &vc, sizeof(vc));
 4289         if (error)
 4290                 return (error);
 4291         if (vc.vc_vers != VFS_CTL_VERS1)
 4292                 return (EINVAL);
 4293         mp = vfs_getvfs(&vc.vc_fsid);
 4294         if (mp == NULL)
 4295                 return (ENOENT);
 4296         /* ensure that a specific sysctl goes to the right filesystem. */
 4297         if (strcmp(vc.vc_fstypename, "*") != 0 &&
 4298             strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
 4299                 vfs_rel(mp);
 4300                 return (EINVAL);
 4301         }
 4302         VCTLTOREQ(&vc, req);
 4303         error = VFS_SYSCTL(mp, vc.vc_op, req);
 4304         vfs_rel(mp);
 4305         return (error);
 4306 }
 4307 
 4308 SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLTYPE_OPAQUE | CTLFLAG_WR,
 4309     NULL, 0, sysctl_vfs_ctl, "",
 4310     "Sysctl by fsid");
 4311 
 4312 /*
 4313  * Function to initialize a va_filerev field sensibly.
 4314  * XXX: Wouldn't a random number make a lot more sense ??
 4315  */
 4316 u_quad_t
 4317 init_va_filerev(void)
 4318 {
 4319         struct bintime bt;
 4320 
 4321         getbinuptime(&bt);
 4322         return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
 4323 }
 4324 
 4325 static int      filt_vfsread(struct knote *kn, long hint);
 4326 static int      filt_vfswrite(struct knote *kn, long hint);
 4327 static int      filt_vfsvnode(struct knote *kn, long hint);
 4328 static void     filt_vfsdetach(struct knote *kn);
 4329 static struct filterops vfsread_filtops = {
 4330         .f_isfd = 1,
 4331         .f_detach = filt_vfsdetach,
 4332         .f_event = filt_vfsread
 4333 };
 4334 static struct filterops vfswrite_filtops = {
 4335         .f_isfd = 1,
 4336         .f_detach = filt_vfsdetach,
 4337         .f_event = filt_vfswrite
 4338 };
 4339 static struct filterops vfsvnode_filtops = {
 4340         .f_isfd = 1,
 4341         .f_detach = filt_vfsdetach,
 4342         .f_event = filt_vfsvnode
 4343 };
 4344 
 4345 static void
 4346 vfs_knllock(void *arg)
 4347 {
 4348         struct vnode *vp = arg;
 4349 
 4350         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 4351 }
 4352 
 4353 static void
 4354 vfs_knlunlock(void *arg)
 4355 {
 4356         struct vnode *vp = arg;
 4357 
 4358         VOP_UNLOCK(vp, 0);
 4359 }
 4360 
 4361 static void
 4362 vfs_knl_assert_locked(void *arg)
 4363 {
 4364 #ifdef DEBUG_VFS_LOCKS
 4365         struct vnode *vp = arg;
 4366 
 4367         ASSERT_VOP_LOCKED(vp, "vfs_knl_assert_locked");
 4368 #endif
 4369 }
 4370 
 4371 static void
 4372 vfs_knl_assert_unlocked(void *arg)
 4373 {
 4374 #ifdef DEBUG_VFS_LOCKS
 4375         struct vnode *vp = arg;
 4376 
 4377         ASSERT_VOP_UNLOCKED(vp, "vfs_knl_assert_unlocked");
 4378 #endif
 4379 }
 4380 
 4381 int
 4382 vfs_kqfilter(struct vop_kqfilter_args *ap)
 4383 {
 4384         struct vnode *vp = ap->a_vp;
 4385         struct knote *kn = ap->a_kn;
 4386         struct knlist *knl;
 4387 
 4388         switch (kn->kn_filter) {
 4389         case EVFILT_READ:
 4390                 kn->kn_fop = &vfsread_filtops;
 4391                 break;
 4392         case EVFILT_WRITE:
 4393                 kn->kn_fop = &vfswrite_filtops;
 4394                 break;
 4395         case EVFILT_VNODE:
 4396                 kn->kn_fop = &vfsvnode_filtops;
 4397                 break;
 4398         default:
 4399                 return (EINVAL);
 4400         }
 4401 
 4402         kn->kn_hook = (caddr_t)vp;
 4403 
 4404         v_addpollinfo(vp);
 4405         if (vp->v_pollinfo == NULL)
 4406                 return (ENOMEM);
 4407         knl = &vp->v_pollinfo->vpi_selinfo.si_note;
 4408         vhold(vp);
 4409         knlist_add(knl, kn, 0);
 4410 
 4411         return (0);
 4412 }
 4413 
 4414 /*
 4415  * Detach knote from vnode
 4416  */
 4417 static void
 4418 filt_vfsdetach(struct knote *kn)
 4419 {
 4420         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4421 
 4422         KASSERT(vp->v_pollinfo != NULL, ("Missing v_pollinfo"));
 4423         knlist_remove(&vp->v_pollinfo->vpi_selinfo.si_note, kn, 0);
 4424         vdrop(vp);
 4425 }
 4426 
 4427 /*ARGSUSED*/
 4428 static int
 4429 filt_vfsread(struct knote *kn, long hint)
 4430 {
 4431         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4432         struct vattr va;
 4433         int res;
 4434 
 4435         /*
 4436          * filesystem is gone, so set the EOF flag and schedule
 4437          * the knote for deletion.
 4438          */
 4439         if (hint == NOTE_REVOKE) {
 4440                 VI_LOCK(vp);
 4441                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4442                 VI_UNLOCK(vp);
 4443                 return (1);
 4444         }
 4445 
 4446         if (VOP_GETATTR(vp, &va, curthread->td_ucred))
 4447                 return (0);
 4448 
 4449         VI_LOCK(vp);
 4450         kn->kn_data = va.va_size - kn->kn_fp->f_offset;
 4451         res = (kn->kn_data != 0);
 4452         VI_UNLOCK(vp);
 4453         return (res);
 4454 }
 4455 
 4456 /*ARGSUSED*/
 4457 static int
 4458 filt_vfswrite(struct knote *kn, long hint)
 4459 {
 4460         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4461 
 4462         VI_LOCK(vp);
 4463 
 4464         /*
 4465          * filesystem is gone, so set the EOF flag and schedule
 4466          * the knote for deletion.
 4467          */
 4468         if (hint == NOTE_REVOKE)
 4469                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4470 
 4471         kn->kn_data = 0;
 4472         VI_UNLOCK(vp);
 4473         return (1);
 4474 }
 4475 
 4476 static int
 4477 filt_vfsvnode(struct knote *kn, long hint)
 4478 {
 4479         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4480         int res;
 4481 
 4482         VI_LOCK(vp);
 4483         if (kn->kn_sfflags & hint)
 4484                 kn->kn_fflags |= hint;
 4485         if (hint == NOTE_REVOKE) {
 4486                 kn->kn_flags |= EV_EOF;
 4487                 VI_UNLOCK(vp);
 4488                 return (1);
 4489         }
 4490         res = (kn->kn_fflags != 0);
 4491         VI_UNLOCK(vp);
 4492         return (res);
 4493 }
 4494 
 4495 int
 4496 vfs_read_dirent(struct vop_readdir_args *ap, struct dirent *dp, off_t off)
 4497 {
 4498         int error;
 4499 
 4500         if (dp->d_reclen > ap->a_uio->uio_resid)
 4501                 return (ENAMETOOLONG);
 4502         error = uiomove(dp, dp->d_reclen, ap->a_uio);
 4503         if (error) {
 4504                 if (ap->a_ncookies != NULL) {
 4505                         if (ap->a_cookies != NULL)
 4506                                 free(ap->a_cookies, M_TEMP);
 4507                         ap->a_cookies = NULL;
 4508                         *ap->a_ncookies = 0;
 4509                 }
 4510                 return (error);
 4511         }
 4512         if (ap->a_ncookies == NULL)
 4513                 return (0);
 4514 
 4515         KASSERT(ap->a_cookies,
 4516             ("NULL ap->a_cookies value with non-NULL ap->a_ncookies!"));
 4517 
 4518         *ap->a_cookies = realloc(*ap->a_cookies,
 4519             (*ap->a_ncookies + 1) * sizeof(u_long), M_TEMP, M_WAITOK | M_ZERO);
 4520         (*ap->a_cookies)[*ap->a_ncookies] = off;
 4521         return (0);
 4522 }
 4523 
 4524 /*
 4525  * Mark for update the access time of the file if the filesystem
 4526  * supports VOP_MARKATIME.  This functionality is used by execve and
 4527  * mmap, so we want to avoid the I/O implied by directly setting
 4528  * va_atime for the sake of efficiency.
 4529  */
 4530 void
 4531 vfs_mark_atime(struct vnode *vp, struct ucred *cred)
 4532 {
 4533         struct mount *mp;
 4534 
 4535         mp = vp->v_mount;
 4536         ASSERT_VOP_LOCKED(vp, "vfs_mark_atime");
 4537         if (mp != NULL && (mp->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0)
 4538                 (void)VOP_MARKATIME(vp);
 4539 }
 4540 
 4541 /*
 4542  * The purpose of this routine is to remove granularity from accmode_t,
 4543  * reducing it into standard unix access bits - VEXEC, VREAD, VWRITE,
 4544  * VADMIN and VAPPEND.
 4545  *
 4546  * If it returns 0, the caller is supposed to continue with the usual
 4547  * access checks using 'accmode' as modified by this routine.  If it
 4548  * returns nonzero value, the caller is supposed to return that value
 4549  * as errno.
 4550  *
 4551  * Note that after this routine runs, accmode may be zero.
 4552  */
 4553 int
 4554 vfs_unixify_accmode(accmode_t *accmode)
 4555 {
 4556         /*
 4557          * There is no way to specify explicit "deny" rule using
 4558          * file mode or POSIX.1e ACLs.
 4559          */
 4560         if (*accmode & VEXPLICIT_DENY) {
 4561                 *accmode = 0;
 4562                 return (0);
 4563         }
 4564 
 4565         /*
 4566          * None of these can be translated into usual access bits.
 4567          * Also, the common case for NFSv4 ACLs is to not contain
 4568          * either of these bits. Caller should check for VWRITE
 4569          * on the containing directory instead.
 4570          */
 4571         if (*accmode & (VDELETE_CHILD | VDELETE))
 4572                 return (EPERM);
 4573 
 4574         if (*accmode & VADMIN_PERMS) {
 4575                 *accmode &= ~VADMIN_PERMS;
 4576                 *accmode |= VADMIN;
 4577         }
 4578 
 4579         /*
 4580          * There is no way to deny VREAD_ATTRIBUTES, VREAD_ACL
 4581          * or VSYNCHRONIZE using file mode or POSIX.1e ACL.
 4582          */
 4583         *accmode &= ~(VSTAT_PERMS | VSYNCHRONIZE);
 4584 
 4585         return (0);
 4586 }
 4587 
 4588 /*
 4589  * These are helper functions for filesystems to traverse all
 4590  * their vnodes.  See MNT_VNODE_FOREACH_ALL() in sys/mount.h.
 4591  *
 4592  * This interface replaces MNT_VNODE_FOREACH.
 4593  */
 4594 
 4595 MALLOC_DEFINE(M_VNODE_MARKER, "vnodemarker", "vnode marker");
 4596 
 4597 struct vnode *
 4598 __mnt_vnode_next_all(struct vnode **mvp, struct mount *mp)
 4599 {
 4600         struct vnode *vp;
 4601 
 4602         if (should_yield())
 4603                 kern_yield(PRI_USER);
 4604         MNT_ILOCK(mp);
 4605         KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
 4606         vp = TAILQ_NEXT(*mvp, v_nmntvnodes);
 4607         while (vp != NULL && (vp->v_type == VMARKER ||
 4608             (vp->v_iflag & VI_DOOMED) != 0))
 4609                 vp = TAILQ_NEXT(vp, v_nmntvnodes);
 4610 
 4611         /* Check if we are done */
 4612         if (vp == NULL) {
 4613                 __mnt_vnode_markerfree_all(mvp, mp);
 4614                 /* MNT_IUNLOCK(mp); -- done in above function */
 4615                 mtx_assert(MNT_MTX(mp), MA_NOTOWNED);
 4616                 return (NULL);
 4617         }
 4618         TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
 4619         TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
 4620         VI_LOCK(vp);
 4621         MNT_IUNLOCK(mp);
 4622         return (vp);
 4623 }
 4624 
 4625 struct vnode *
 4626 __mnt_vnode_first_all(struct vnode **mvp, struct mount *mp)
 4627 {
 4628         struct vnode *vp;
 4629 
 4630         *mvp = malloc(sizeof(struct vnode), M_VNODE_MARKER, M_WAITOK | M_ZERO);
 4631         MNT_ILOCK(mp);
 4632         MNT_REF(mp);
 4633         (*mvp)->v_type = VMARKER;
 4634 
 4635         vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
 4636         while (vp != NULL && (vp->v_type == VMARKER ||
 4637             (vp->v_iflag & VI_DOOMED) != 0))
 4638                 vp = TAILQ_NEXT(vp, v_nmntvnodes);
 4639 
 4640         /* Check if we are done */
 4641         if (vp == NULL) {
 4642                 MNT_REL(mp);
 4643                 MNT_IUNLOCK(mp);
 4644                 free(*mvp, M_VNODE_MARKER);
 4645                 *mvp = NULL;
 4646                 return (NULL);
 4647         }
 4648         (*mvp)->v_mount = mp;
 4649         TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
 4650         VI_LOCK(vp);
 4651         MNT_IUNLOCK(mp);
 4652         return (vp);
 4653 }
 4654 
 4655 
 4656 void
 4657 __mnt_vnode_markerfree_all(struct vnode **mvp, struct mount *mp)
 4658 {
 4659 
 4660         if (*mvp == NULL) {
 4661                 MNT_IUNLOCK(mp);
 4662                 return;
 4663         }
 4664 
 4665         mtx_assert(MNT_MTX(mp), MA_OWNED);
 4666 
 4667         KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
 4668         TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
 4669         MNT_REL(mp);
 4670         MNT_IUNLOCK(mp);
 4671         free(*mvp, M_VNODE_MARKER);
 4672         *mvp = NULL;
 4673 }
 4674 
 4675 /*
 4676  * These are helper functions for filesystems to traverse their
 4677  * active vnodes.  See MNT_VNODE_FOREACH_ACTIVE() in sys/mount.h
 4678  */
 4679 static void
 4680 mnt_vnode_markerfree_active(struct vnode **mvp, struct mount *mp)
 4681 {
 4682 
 4683         KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
 4684 
 4685         MNT_ILOCK(mp);
 4686         MNT_REL(mp);
 4687         MNT_IUNLOCK(mp);
 4688         free(*mvp, M_VNODE_MARKER);
 4689         *mvp = NULL;
 4690 }
 4691 
 4692 static struct vnode *
 4693 mnt_vnode_next_active(struct vnode **mvp, struct mount *mp)
 4694 {
 4695         struct vnode *vp, *nvp;
 4696 
 4697         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
 4698         KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
 4699 restart:
 4700         vp = TAILQ_NEXT(*mvp, v_actfreelist);
 4701         TAILQ_REMOVE(&mp->mnt_activevnodelist, *mvp, v_actfreelist);
 4702         while (vp != NULL) {
 4703                 if (vp->v_type == VMARKER) {
 4704                         vp = TAILQ_NEXT(vp, v_actfreelist);
 4705                         continue;
 4706                 }
 4707                 if (!VI_TRYLOCK(vp)) {
 4708                         if (mp_ncpus == 1 || should_yield()) {
 4709                                 TAILQ_INSERT_BEFORE(vp, *mvp, v_actfreelist);
 4710                                 mtx_unlock(&vnode_free_list_mtx);
 4711                                 pause("vnacti", 1);
 4712                                 mtx_lock(&vnode_free_list_mtx);
 4713                                 goto restart;
 4714                         }
 4715                         continue;
 4716                 }
 4717                 KASSERT(vp->v_type != VMARKER, ("locked marker %p", vp));
 4718                 KASSERT(vp->v_mount == mp || vp->v_mount == NULL,
 4719                     ("alien vnode on the active list %p %p", vp, mp));
 4720                 if (vp->v_mount == mp && (vp->v_iflag & VI_DOOMED) == 0)
 4721                         break;
 4722                 nvp = TAILQ_NEXT(vp, v_actfreelist);
 4723                 VI_UNLOCK(vp);
 4724                 vp = nvp;
 4725         }
 4726 
 4727         /* Check if we are done */
 4728         if (vp == NULL) {
 4729                 mtx_unlock(&vnode_free_list_mtx);
 4730                 mnt_vnode_markerfree_active(mvp, mp);
 4731                 return (NULL);
 4732         }
 4733         TAILQ_INSERT_AFTER(&mp->mnt_activevnodelist, vp, *mvp, v_actfreelist);
 4734         mtx_unlock(&vnode_free_list_mtx);
 4735         ASSERT_VI_LOCKED(vp, "active iter");
 4736         KASSERT((vp->v_iflag & VI_ACTIVE) != 0, ("Non-active vp %p", vp));
 4737         return (vp);
 4738 }
 4739 
 4740 struct vnode *
 4741 __mnt_vnode_next_active(struct vnode **mvp, struct mount *mp)
 4742 {
 4743 
 4744         if (should_yield())
 4745                 kern_yield(PRI_USER);
 4746         mtx_lock(&vnode_free_list_mtx);
 4747         return (mnt_vnode_next_active(mvp, mp));
 4748 }
 4749 
 4750 struct vnode *
 4751 __mnt_vnode_first_active(struct vnode **mvp, struct mount *mp)
 4752 {
 4753         struct vnode *vp;
 4754 
 4755         *mvp = malloc(sizeof(struct vnode), M_VNODE_MARKER, M_WAITOK | M_ZERO);
 4756         MNT_ILOCK(mp);
 4757         MNT_REF(mp);
 4758         MNT_IUNLOCK(mp);
 4759         (*mvp)->v_type = VMARKER;
 4760         (*mvp)->v_mount = mp;
 4761 
 4762         mtx_lock(&vnode_free_list_mtx);
 4763         vp = TAILQ_FIRST(&mp->mnt_activevnodelist);
 4764         if (vp == NULL) {
 4765                 mtx_unlock(&vnode_free_list_mtx);
 4766                 mnt_vnode_markerfree_active(mvp, mp);
 4767                 return (NULL);
 4768         }
 4769         TAILQ_INSERT_BEFORE(vp, *mvp, v_actfreelist);
 4770         return (mnt_vnode_next_active(mvp, mp));
 4771 }
 4772 
 4773 void
 4774 __mnt_vnode_markerfree_active(struct vnode **mvp, struct mount *mp)
 4775 {
 4776 
 4777         if (*mvp == NULL)
 4778                 return;
 4779 
 4780         mtx_lock(&vnode_free_list_mtx);
 4781         TAILQ_REMOVE(&mp->mnt_activevnodelist, *mvp, v_actfreelist);
 4782         mtx_unlock(&vnode_free_list_mtx);
 4783         mnt_vnode_markerfree_active(mvp, mp);
 4784 }

Cache object: 9dd8b1f70f783d78b1f6c46ba2adca26


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