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/8.0/sys/kern/vfs_subr.c 197123 2009-09-12 18:02:57Z kib $");
   43 
   44 #include "opt_ddb.h"
   45 
   46 #include <sys/param.h>
   47 #include <sys/systm.h>
   48 #include <sys/bio.h>
   49 #include <sys/buf.h>
   50 #include <sys/condvar.h>
   51 #include <sys/conf.h>
   52 #include <sys/dirent.h>
   53 #include <sys/event.h>
   54 #include <sys/eventhandler.h>
   55 #include <sys/extattr.h>
   56 #include <sys/file.h>
   57 #include <sys/fcntl.h>
   58 #include <sys/jail.h>
   59 #include <sys/kdb.h>
   60 #include <sys/kernel.h>
   61 #include <sys/kthread.h>
   62 #include <sys/lockf.h>
   63 #include <sys/malloc.h>
   64 #include <sys/mount.h>
   65 #include <sys/namei.h>
   66 #include <sys/priv.h>
   67 #include <sys/reboot.h>
   68 #include <sys/sleepqueue.h>
   69 #include <sys/stat.h>
   70 #include <sys/sysctl.h>
   71 #include <sys/syslog.h>
   72 #include <sys/vmmeter.h>
   73 #include <sys/vnode.h>
   74 
   75 #include <machine/stdarg.h>
   76 
   77 #include <security/mac/mac_framework.h>
   78 
   79 #include <vm/vm.h>
   80 #include <vm/vm_object.h>
   81 #include <vm/vm_extern.h>
   82 #include <vm/pmap.h>
   83 #include <vm/vm_map.h>
   84 #include <vm/vm_page.h>
   85 #include <vm/vm_kern.h>
   86 #include <vm/uma.h>
   87 
   88 #ifdef DDB
   89 #include <ddb/ddb.h>
   90 #endif
   91 
   92 #define WI_MPSAFEQ      0
   93 #define WI_GIANTQ       1
   94 
   95 static MALLOC_DEFINE(M_NETADDR, "subr_export_host", "Export host address structure");
   96 
   97 static void     delmntque(struct vnode *vp);
   98 static int      flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo,
   99                     int slpflag, int slptimeo);
  100 static void     syncer_shutdown(void *arg, int howto);
  101 static int      vtryrecycle(struct vnode *vp);
  102 static void     vbusy(struct vnode *vp);
  103 static void     vinactive(struct vnode *, struct thread *);
  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     vfree(struct vnode *);
  109 static void     vnlru_free(int);
  110 static void     vgonel(struct vnode *);
  111 static void     vfs_knllock(void *arg);
  112 static void     vfs_knlunlock(void *arg);
  113 static void     vfs_knl_assert_locked(void *arg);
  114 static void     vfs_knl_assert_unlocked(void *arg);
  115 static void     destroy_vpollinfo(struct vpollinfo *vi);
  116 
  117 /*
  118  * Number of vnodes in existence.  Increased whenever getnewvnode()
  119  * allocates a new vnode, decreased on vdestroy() called on VI_DOOMed
  120  * vnode.
  121  */
  122 static unsigned long    numvnodes;
  123 
  124 SYSCTL_LONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
  125 
  126 /*
  127  * Conversion tables for conversion from vnode types to inode formats
  128  * and back.
  129  */
  130 enum vtype iftovt_tab[16] = {
  131         VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
  132         VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
  133 };
  134 int vttoif_tab[10] = {
  135         0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
  136         S_IFSOCK, S_IFIFO, S_IFMT, S_IFMT
  137 };
  138 
  139 /*
  140  * List of vnodes that are ready for recycling.
  141  */
  142 static TAILQ_HEAD(freelst, vnode) vnode_free_list;
  143 
  144 /*
  145  * Free vnode target.  Free vnodes may simply be files which have been stat'd
  146  * but not read.  This is somewhat common, and a small cache of such files
  147  * should be kept to avoid recreation costs.
  148  */
  149 static u_long wantfreevnodes;
  150 SYSCTL_LONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
  151 /* Number of vnodes in the free list. */
  152 static u_long freevnodes;
  153 SYSCTL_LONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "");
  154 
  155 /*
  156  * Various variables used for debugging the new implementation of
  157  * reassignbuf().
  158  * XXX these are probably of (very) limited utility now.
  159  */
  160 static int reassignbufcalls;
  161 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0, "");
  162 
  163 /*
  164  * Cache for the mount type id assigned to NFS.  This is used for
  165  * special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
  166  */
  167 int     nfs_mount_type = -1;
  168 
  169 /* To keep more than one thread at a time from running vfs_getnewfsid */
  170 static struct mtx mntid_mtx;
  171 
  172 /*
  173  * Lock for any access to the following:
  174  *      vnode_free_list
  175  *      numvnodes
  176  *      freevnodes
  177  */
  178 static struct mtx vnode_free_list_mtx;
  179 
  180 /* Publicly exported FS */
  181 struct nfs_public nfs_pub;
  182 
  183 /* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
  184 static uma_zone_t vnode_zone;
  185 static uma_zone_t vnodepoll_zone;
  186 
  187 /* Set to 1 to print out reclaim of active vnodes */
  188 int     prtactive;
  189 
  190 /*
  191  * The workitem queue.
  192  *
  193  * It is useful to delay writes of file data and filesystem metadata
  194  * for tens of seconds so that quickly created and deleted files need
  195  * not waste disk bandwidth being created and removed. To realize this,
  196  * we append vnodes to a "workitem" queue. When running with a soft
  197  * updates implementation, most pending metadata dependencies should
  198  * not wait for more than a few seconds. Thus, mounted on block devices
  199  * are delayed only about a half the time that file data is delayed.
  200  * Similarly, directory updates are more critical, so are only delayed
  201  * about a third the time that file data is delayed. Thus, there are
  202  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
  203  * one each second (driven off the filesystem syncer process). The
  204  * syncer_delayno variable indicates the next queue that is to be processed.
  205  * Items that need to be processed soon are placed in this queue:
  206  *
  207  *      syncer_workitem_pending[syncer_delayno]
  208  *
  209  * A delay of fifteen seconds is done by placing the request fifteen
  210  * entries later in the queue:
  211  *
  212  *      syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
  213  *
  214  */
  215 static int syncer_delayno;
  216 static long syncer_mask;
  217 LIST_HEAD(synclist, bufobj);
  218 static struct synclist *syncer_workitem_pending[2];
  219 /*
  220  * The sync_mtx protects:
  221  *      bo->bo_synclist
  222  *      sync_vnode_count
  223  *      syncer_delayno
  224  *      syncer_state
  225  *      syncer_workitem_pending
  226  *      syncer_worklist_len
  227  *      rushjob
  228  */
  229 static struct mtx sync_mtx;
  230 static struct cv sync_wakeup;
  231 
  232 #define SYNCER_MAXDELAY         32
  233 static int syncer_maxdelay = SYNCER_MAXDELAY;   /* maximum delay time */
  234 static int syncdelay = 30;              /* max time to delay syncing data */
  235 static int filedelay = 30;              /* time to delay syncing files */
  236 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "");
  237 static int dirdelay = 29;               /* time to delay syncing directories */
  238 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "");
  239 static int metadelay = 28;              /* time to delay syncing metadata */
  240 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "");
  241 static int rushjob;             /* number of slots to run ASAP */
  242 static int stat_rush_requests;  /* number of times I/O speeded up */
  243 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0, "");
  244 
  245 /*
  246  * When shutting down the syncer, run it at four times normal speed.
  247  */
  248 #define SYNCER_SHUTDOWN_SPEEDUP         4
  249 static int sync_vnode_count;
  250 static int syncer_worklist_len;
  251 static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
  252     syncer_state;
  253 
  254 /*
  255  * Number of vnodes we want to exist at any one time.  This is mostly used
  256  * to size hash tables in vnode-related code.  It is normally not used in
  257  * getnewvnode(), as wantfreevnodes is normally nonzero.)
  258  *
  259  * XXX desiredvnodes is historical cruft and should not exist.
  260  */
  261 int desiredvnodes;
  262 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
  263     &desiredvnodes, 0, "Maximum number of vnodes");
  264 SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
  265     &wantfreevnodes, 0, "Minimum number of vnodes (legacy)");
  266 static int vnlru_nowhere;
  267 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
  268     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
  269 
  270 /*
  271  * Macros to control when a vnode is freed and recycled.  All require
  272  * the vnode interlock.
  273  */
  274 #define VCANRECYCLE(vp) (((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  275 #define VSHOULDFREE(vp) (!((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  276 #define VSHOULDBUSY(vp) (((vp)->v_iflag & VI_FREE) && (vp)->v_holdcnt)
  277 
  278 
  279 /*
  280  * Initialize the vnode management data structures.
  281  */
  282 #ifndef MAXVNODES_MAX
  283 #define MAXVNODES_MAX   100000
  284 #endif
  285 static void
  286 vntblinit(void *dummy __unused)
  287 {
  288 
  289         /*
  290          * Desiredvnodes is a function of the physical memory size and
  291          * the kernel's heap size.  Specifically, desiredvnodes scales
  292          * in proportion to the physical memory size until two fifths
  293          * of the kernel's heap size is consumed by vnodes and vm
  294          * objects.
  295          */
  296         desiredvnodes = min(maxproc + cnt.v_page_count / 4, 2 * vm_kmem_size /
  297             (5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
  298         if (desiredvnodes > MAXVNODES_MAX) {
  299                 if (bootverbose)
  300                         printf("Reducing kern.maxvnodes %d -> %d\n",
  301                             desiredvnodes, MAXVNODES_MAX);
  302                 desiredvnodes = MAXVNODES_MAX;
  303         }
  304         wantfreevnodes = desiredvnodes / 4;
  305         mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
  306         TAILQ_INIT(&vnode_free_list);
  307         mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
  308         vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
  309             NULL, NULL, UMA_ALIGN_PTR, 0);
  310         vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
  311             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  312         /*
  313          * Initialize the filesystem syncer.
  314          */
  315         syncer_workitem_pending[WI_MPSAFEQ] = hashinit(syncer_maxdelay, M_VNODE,
  316             &syncer_mask);
  317         syncer_workitem_pending[WI_GIANTQ] = hashinit(syncer_maxdelay, M_VNODE,
  318             &syncer_mask);
  319         syncer_maxdelay = syncer_mask + 1;
  320         mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
  321         cv_init(&sync_wakeup, "syncer");
  322 }
  323 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL);
  324 
  325 
  326 /*
  327  * Mark a mount point as busy. Used to synchronize access and to delay
  328  * unmounting. Eventually, mountlist_mtx is not released on failure.
  329  */
  330 int
  331 vfs_busy(struct mount *mp, int flags)
  332 {
  333 
  334         MPASS((flags & ~MBF_MASK) == 0);
  335         CTR3(KTR_VFS, "%s: mp %p with flags %d", __func__, mp, flags);
  336 
  337         MNT_ILOCK(mp);
  338         MNT_REF(mp);
  339         /*
  340          * If mount point is currenly being unmounted, sleep until the
  341          * mount point fate is decided.  If thread doing the unmounting fails,
  342          * it will clear MNTK_UNMOUNT flag before waking us up, indicating
  343          * that this mount point has survived the unmount attempt and vfs_busy
  344          * should retry.  Otherwise the unmounter thread will set MNTK_REFEXPIRE
  345          * flag in addition to MNTK_UNMOUNT, indicating that mount point is
  346          * about to be really destroyed.  vfs_busy needs to release its
  347          * reference on the mount point in this case and return with ENOENT,
  348          * telling the caller that mount mount it tried to busy is no longer
  349          * valid.
  350          */
  351         while (mp->mnt_kern_flag & MNTK_UNMOUNT) {
  352                 if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) {
  353                         MNT_REL(mp);
  354                         MNT_IUNLOCK(mp);
  355                         CTR1(KTR_VFS, "%s: failed busying before sleeping",
  356                             __func__);
  357                         return (ENOENT);
  358                 }
  359                 if (flags & MBF_MNTLSTLOCK)
  360                         mtx_unlock(&mountlist_mtx);
  361                 mp->mnt_kern_flag |= MNTK_MWAIT;
  362                 msleep(mp, MNT_MTX(mp), PVFS, "vfs_busy", 0);
  363                 if (flags & MBF_MNTLSTLOCK)
  364                         mtx_lock(&mountlist_mtx);
  365         }
  366         if (flags & MBF_MNTLSTLOCK)
  367                 mtx_unlock(&mountlist_mtx);
  368         mp->mnt_lockref++;
  369         MNT_IUNLOCK(mp);
  370         return (0);
  371 }
  372 
  373 /*
  374  * Free a busy filesystem.
  375  */
  376 void
  377 vfs_unbusy(struct mount *mp)
  378 {
  379 
  380         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  381         MNT_ILOCK(mp);
  382         MNT_REL(mp);
  383         KASSERT(mp->mnt_lockref > 0, ("negative mnt_lockref"));
  384         mp->mnt_lockref--;
  385         if (mp->mnt_lockref == 0 && (mp->mnt_kern_flag & MNTK_DRAINING) != 0) {
  386                 MPASS(mp->mnt_kern_flag & MNTK_UNMOUNT);
  387                 CTR1(KTR_VFS, "%s: waking up waiters", __func__);
  388                 mp->mnt_kern_flag &= ~MNTK_DRAINING;
  389                 wakeup(&mp->mnt_lockref);
  390         }
  391         MNT_IUNLOCK(mp);
  392 }
  393 
  394 /*
  395  * Lookup a mount point by filesystem identifier.
  396  */
  397 struct mount *
  398 vfs_getvfs(fsid_t *fsid)
  399 {
  400         struct mount *mp;
  401 
  402         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  403         mtx_lock(&mountlist_mtx);
  404         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  405                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  406                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  407                         vfs_ref(mp);
  408                         mtx_unlock(&mountlist_mtx);
  409                         return (mp);
  410                 }
  411         }
  412         mtx_unlock(&mountlist_mtx);
  413         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  414         return ((struct mount *) 0);
  415 }
  416 
  417 /*
  418  * Lookup a mount point by filesystem identifier, busying it before
  419  * returning.
  420  */
  421 struct mount *
  422 vfs_busyfs(fsid_t *fsid)
  423 {
  424         struct mount *mp;
  425         int error;
  426 
  427         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  428         mtx_lock(&mountlist_mtx);
  429         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  430                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  431                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  432                         error = vfs_busy(mp, MBF_MNTLSTLOCK);
  433                         if (error) {
  434                                 mtx_unlock(&mountlist_mtx);
  435                                 return (NULL);
  436                         }
  437                         return (mp);
  438                 }
  439         }
  440         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  441         mtx_unlock(&mountlist_mtx);
  442         return ((struct mount *) 0);
  443 }
  444 
  445 /*
  446  * Check if a user can access privileged mount options.
  447  */
  448 int
  449 vfs_suser(struct mount *mp, struct thread *td)
  450 {
  451         int error;
  452 
  453         /*
  454          * If the thread is jailed, but this is not a jail-friendly file
  455          * system, deny immediately.
  456          */
  457         if (!(mp->mnt_vfc->vfc_flags & VFCF_JAIL) && jailed(td->td_ucred))
  458                 return (EPERM);
  459 
  460         /*
  461          * If the file system was mounted outside the jail of the calling
  462          * thread, deny immediately.
  463          */
  464         if (prison_check(td->td_ucred, mp->mnt_cred) != 0)
  465                 return (EPERM);
  466 
  467         /*
  468          * If file system supports delegated administration, we don't check
  469          * for the PRIV_VFS_MOUNT_OWNER privilege - it will be better verified
  470          * by the file system itself.
  471          * If this is not the user that did original mount, we check for
  472          * the PRIV_VFS_MOUNT_OWNER privilege.
  473          */
  474         if (!(mp->mnt_vfc->vfc_flags & VFCF_DELEGADMIN) &&
  475             mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
  476                 if ((error = priv_check(td, PRIV_VFS_MOUNT_OWNER)) != 0)
  477                         return (error);
  478         }
  479         return (0);
  480 }
  481 
  482 /*
  483  * Get a new unique fsid.  Try to make its val[0] unique, since this value
  484  * will be used to create fake device numbers for stat().  Also try (but
  485  * not so hard) make its val[0] unique mod 2^16, since some emulators only
  486  * support 16-bit device numbers.  We end up with unique val[0]'s for the
  487  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
  488  *
  489  * Keep in mind that several mounts may be running in parallel.  Starting
  490  * the search one past where the previous search terminated is both a
  491  * micro-optimization and a defense against returning the same fsid to
  492  * different mounts.
  493  */
  494 void
  495 vfs_getnewfsid(struct mount *mp)
  496 {
  497         static u_int16_t mntid_base;
  498         struct mount *nmp;
  499         fsid_t tfsid;
  500         int mtype;
  501 
  502         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  503         mtx_lock(&mntid_mtx);
  504         mtype = mp->mnt_vfc->vfc_typenum;
  505         tfsid.val[1] = mtype;
  506         mtype = (mtype & 0xFF) << 24;
  507         for (;;) {
  508                 tfsid.val[0] = makedev(255,
  509                     mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
  510                 mntid_base++;
  511                 if ((nmp = vfs_getvfs(&tfsid)) == NULL)
  512                         break;
  513                 vfs_rel(nmp);
  514         }
  515         mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
  516         mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
  517         mtx_unlock(&mntid_mtx);
  518 }
  519 
  520 /*
  521  * Knob to control the precision of file timestamps:
  522  *
  523  *   0 = seconds only; nanoseconds zeroed.
  524  *   1 = seconds and nanoseconds, accurate within 1/HZ.
  525  *   2 = seconds and nanoseconds, truncated to microseconds.
  526  * >=3 = seconds and nanoseconds, maximum precision.
  527  */
  528 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
  529 
  530 static int timestamp_precision = TSP_SEC;
  531 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
  532     &timestamp_precision, 0, "");
  533 
  534 /*
  535  * Get a current timestamp.
  536  */
  537 void
  538 vfs_timestamp(struct timespec *tsp)
  539 {
  540         struct timeval tv;
  541 
  542         switch (timestamp_precision) {
  543         case TSP_SEC:
  544                 tsp->tv_sec = time_second;
  545                 tsp->tv_nsec = 0;
  546                 break;
  547         case TSP_HZ:
  548                 getnanotime(tsp);
  549                 break;
  550         case TSP_USEC:
  551                 microtime(&tv);
  552                 TIMEVAL_TO_TIMESPEC(&tv, tsp);
  553                 break;
  554         case TSP_NSEC:
  555         default:
  556                 nanotime(tsp);
  557                 break;
  558         }
  559 }
  560 
  561 /*
  562  * Set vnode attributes to VNOVAL
  563  */
  564 void
  565 vattr_null(struct vattr *vap)
  566 {
  567 
  568         vap->va_type = VNON;
  569         vap->va_size = VNOVAL;
  570         vap->va_bytes = VNOVAL;
  571         vap->va_mode = VNOVAL;
  572         vap->va_nlink = VNOVAL;
  573         vap->va_uid = VNOVAL;
  574         vap->va_gid = VNOVAL;
  575         vap->va_fsid = VNOVAL;
  576         vap->va_fileid = VNOVAL;
  577         vap->va_blocksize = VNOVAL;
  578         vap->va_rdev = VNOVAL;
  579         vap->va_atime.tv_sec = VNOVAL;
  580         vap->va_atime.tv_nsec = VNOVAL;
  581         vap->va_mtime.tv_sec = VNOVAL;
  582         vap->va_mtime.tv_nsec = VNOVAL;
  583         vap->va_ctime.tv_sec = VNOVAL;
  584         vap->va_ctime.tv_nsec = VNOVAL;
  585         vap->va_birthtime.tv_sec = VNOVAL;
  586         vap->va_birthtime.tv_nsec = VNOVAL;
  587         vap->va_flags = VNOVAL;
  588         vap->va_gen = VNOVAL;
  589         vap->va_vaflags = 0;
  590 }
  591 
  592 /*
  593  * This routine is called when we have too many vnodes.  It attempts
  594  * to free <count> vnodes and will potentially free vnodes that still
  595  * have VM backing store (VM backing store is typically the cause
  596  * of a vnode blowout so we want to do this).  Therefore, this operation
  597  * is not considered cheap.
  598  *
  599  * A number of conditions may prevent a vnode from being reclaimed.
  600  * the buffer cache may have references on the vnode, a directory
  601  * vnode may still have references due to the namei cache representing
  602  * underlying files, or the vnode may be in active use.   It is not
  603  * desireable to reuse such vnodes.  These conditions may cause the
  604  * number of vnodes to reach some minimum value regardless of what
  605  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
  606  */
  607 static int
  608 vlrureclaim(struct mount *mp)
  609 {
  610         struct vnode *vp;
  611         int done;
  612         int trigger;
  613         int usevnodes;
  614         int count;
  615 
  616         /*
  617          * Calculate the trigger point, don't allow user
  618          * screwups to blow us up.   This prevents us from
  619          * recycling vnodes with lots of resident pages.  We
  620          * aren't trying to free memory, we are trying to
  621          * free vnodes.
  622          */
  623         usevnodes = desiredvnodes;
  624         if (usevnodes <= 0)
  625                 usevnodes = 1;
  626         trigger = cnt.v_page_count * 2 / usevnodes;
  627         done = 0;
  628         vn_start_write(NULL, &mp, V_WAIT);
  629         MNT_ILOCK(mp);
  630         count = mp->mnt_nvnodelistsize / 10 + 1;
  631         while (count != 0) {
  632                 vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
  633                 while (vp != NULL && vp->v_type == VMARKER)
  634                         vp = TAILQ_NEXT(vp, v_nmntvnodes);
  635                 if (vp == NULL)
  636                         break;
  637                 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  638                 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  639                 --count;
  640                 if (!VI_TRYLOCK(vp))
  641                         goto next_iter;
  642                 /*
  643                  * If it's been deconstructed already, it's still
  644                  * referenced, or it exceeds the trigger, skip it.
  645                  */
  646                 if (vp->v_usecount || !LIST_EMPTY(&(vp)->v_cache_src) ||
  647                     (vp->v_iflag & VI_DOOMED) != 0 || (vp->v_object != NULL &&
  648                     vp->v_object->resident_page_count > trigger)) {
  649                         VI_UNLOCK(vp);
  650                         goto next_iter;
  651                 }
  652                 MNT_IUNLOCK(mp);
  653                 vholdl(vp);
  654                 if (VOP_LOCK(vp, LK_INTERLOCK|LK_EXCLUSIVE|LK_NOWAIT)) {
  655                         vdrop(vp);
  656                         goto next_iter_mntunlocked;
  657                 }
  658                 VI_LOCK(vp);
  659                 /*
  660                  * v_usecount may have been bumped after VOP_LOCK() dropped
  661                  * the vnode interlock and before it was locked again.
  662                  *
  663                  * It is not necessary to recheck VI_DOOMED because it can
  664                  * only be set by another thread that holds both the vnode
  665                  * lock and vnode interlock.  If another thread has the
  666                  * vnode lock before we get to VOP_LOCK() and obtains the
  667                  * vnode interlock after VOP_LOCK() drops the vnode
  668                  * interlock, the other thread will be unable to drop the
  669                  * vnode lock before our VOP_LOCK() call fails.
  670                  */
  671                 if (vp->v_usecount || !LIST_EMPTY(&(vp)->v_cache_src) ||
  672                     (vp->v_object != NULL &&
  673                     vp->v_object->resident_page_count > trigger)) {
  674                         VOP_UNLOCK(vp, LK_INTERLOCK);
  675                         goto next_iter_mntunlocked;
  676                 }
  677                 KASSERT((vp->v_iflag & VI_DOOMED) == 0,
  678                     ("VI_DOOMED unexpectedly detected in vlrureclaim()"));
  679                 vgonel(vp);
  680                 VOP_UNLOCK(vp, 0);
  681                 vdropl(vp);
  682                 done++;
  683 next_iter_mntunlocked:
  684                 if ((count % 256) != 0)
  685                         goto relock_mnt;
  686                 goto yield;
  687 next_iter:
  688                 if ((count % 256) != 0)
  689                         continue;
  690                 MNT_IUNLOCK(mp);
  691 yield:
  692                 uio_yield();
  693 relock_mnt:
  694                 MNT_ILOCK(mp);
  695         }
  696         MNT_IUNLOCK(mp);
  697         vn_finished_write(mp);
  698         return done;
  699 }
  700 
  701 /*
  702  * Attempt to keep the free list at wantfreevnodes length.
  703  */
  704 static void
  705 vnlru_free(int count)
  706 {
  707         struct vnode *vp;
  708         int vfslocked;
  709 
  710         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
  711         for (; count > 0; count--) {
  712                 vp = TAILQ_FIRST(&vnode_free_list);
  713                 /*
  714                  * The list can be modified while the free_list_mtx
  715                  * has been dropped and vp could be NULL here.
  716                  */
  717                 if (!vp)
  718                         break;
  719                 VNASSERT(vp->v_op != NULL, vp,
  720                     ("vnlru_free: vnode already reclaimed."));
  721                 TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
  722                 /*
  723                  * Don't recycle if we can't get the interlock.
  724                  */
  725                 if (!VI_TRYLOCK(vp)) {
  726                         TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
  727                         continue;
  728                 }
  729                 VNASSERT(VCANRECYCLE(vp), vp,
  730                     ("vp inconsistent on freelist"));
  731                 freevnodes--;
  732                 vp->v_iflag &= ~VI_FREE;
  733                 vholdl(vp);
  734                 mtx_unlock(&vnode_free_list_mtx);
  735                 VI_UNLOCK(vp);
  736                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  737                 vtryrecycle(vp);
  738                 VFS_UNLOCK_GIANT(vfslocked);
  739                 /*
  740                  * If the recycled succeeded this vdrop will actually free
  741                  * the vnode.  If not it will simply place it back on
  742                  * the free list.
  743                  */
  744                 vdrop(vp);
  745                 mtx_lock(&vnode_free_list_mtx);
  746         }
  747 }
  748 /*
  749  * Attempt to recycle vnodes in a context that is always safe to block.
  750  * Calling vlrurecycle() from the bowels of filesystem code has some
  751  * interesting deadlock problems.
  752  */
  753 static struct proc *vnlruproc;
  754 static int vnlruproc_sig;
  755 
  756 static void
  757 vnlru_proc(void)
  758 {
  759         struct mount *mp, *nmp;
  760         int done, vfslocked;
  761         struct proc *p = vnlruproc;
  762 
  763         EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
  764             SHUTDOWN_PRI_FIRST);
  765 
  766         for (;;) {
  767                 kproc_suspend_check(p);
  768                 mtx_lock(&vnode_free_list_mtx);
  769                 if (freevnodes > wantfreevnodes)
  770                         vnlru_free(freevnodes - wantfreevnodes);
  771                 if (numvnodes <= desiredvnodes * 9 / 10) {
  772                         vnlruproc_sig = 0;
  773                         wakeup(&vnlruproc_sig);
  774                         msleep(vnlruproc, &vnode_free_list_mtx,
  775                             PVFS|PDROP, "vlruwt", hz);
  776                         continue;
  777                 }
  778                 mtx_unlock(&vnode_free_list_mtx);
  779                 done = 0;
  780                 mtx_lock(&mountlist_mtx);
  781                 for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
  782                         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
  783                                 nmp = TAILQ_NEXT(mp, mnt_list);
  784                                 continue;
  785                         }
  786                         vfslocked = VFS_LOCK_GIANT(mp);
  787                         done += vlrureclaim(mp);
  788                         VFS_UNLOCK_GIANT(vfslocked);
  789                         mtx_lock(&mountlist_mtx);
  790                         nmp = TAILQ_NEXT(mp, mnt_list);
  791                         vfs_unbusy(mp);
  792                 }
  793                 mtx_unlock(&mountlist_mtx);
  794                 if (done == 0) {
  795                         EVENTHANDLER_INVOKE(vfs_lowvnodes, desiredvnodes / 10);
  796 #if 0
  797                         /* These messages are temporary debugging aids */
  798                         if (vnlru_nowhere < 5)
  799                                 printf("vnlru process getting nowhere..\n");
  800                         else if (vnlru_nowhere == 5)
  801                                 printf("vnlru process messages stopped.\n");
  802 #endif
  803                         vnlru_nowhere++;
  804                         tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
  805                 } else
  806                         uio_yield();
  807         }
  808 }
  809 
  810 static struct kproc_desc vnlru_kp = {
  811         "vnlru",
  812         vnlru_proc,
  813         &vnlruproc
  814 };
  815 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start,
  816     &vnlru_kp);
  817 
  818 /*
  819  * Routines having to do with the management of the vnode table.
  820  */
  821 
  822 void
  823 vdestroy(struct vnode *vp)
  824 {
  825         struct bufobj *bo;
  826 
  827         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  828         mtx_lock(&vnode_free_list_mtx);
  829         numvnodes--;
  830         mtx_unlock(&vnode_free_list_mtx);
  831         bo = &vp->v_bufobj;
  832         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
  833             ("cleaned vnode still on the free list."));
  834         VNASSERT(vp->v_data == NULL, vp, ("cleaned vnode isn't"));
  835         VNASSERT(vp->v_holdcnt == 0, vp, ("Non-zero hold count"));
  836         VNASSERT(vp->v_usecount == 0, vp, ("Non-zero use count"));
  837         VNASSERT(vp->v_writecount == 0, vp, ("Non-zero write count"));
  838         VNASSERT(bo->bo_numoutput == 0, vp, ("Clean vnode has pending I/O's"));
  839         VNASSERT(bo->bo_clean.bv_cnt == 0, vp, ("cleanbufcnt not 0"));
  840         VNASSERT(bo->bo_clean.bv_root == NULL, vp, ("cleanblkroot not NULL"));
  841         VNASSERT(bo->bo_dirty.bv_cnt == 0, vp, ("dirtybufcnt not 0"));
  842         VNASSERT(bo->bo_dirty.bv_root == NULL, vp, ("dirtyblkroot not NULL"));
  843         VNASSERT(TAILQ_EMPTY(&vp->v_cache_dst), vp, ("vp has namecache dst"));
  844         VNASSERT(LIST_EMPTY(&vp->v_cache_src), vp, ("vp has namecache src"));
  845         VNASSERT(vp->v_cache_dd == NULL, vp, ("vp has namecache for .."));
  846         VI_UNLOCK(vp);
  847 #ifdef MAC
  848         mac_vnode_destroy(vp);
  849 #endif
  850         if (vp->v_pollinfo != NULL)
  851                 destroy_vpollinfo(vp->v_pollinfo);
  852 #ifdef INVARIANTS
  853         /* XXX Elsewhere we can detect an already freed vnode via NULL v_op. */
  854         vp->v_op = NULL;
  855 #endif
  856         lockdestroy(vp->v_vnlock);
  857         mtx_destroy(&vp->v_interlock);
  858         mtx_destroy(BO_MTX(bo));
  859         uma_zfree(vnode_zone, vp);
  860 }
  861 
  862 /*
  863  * Try to recycle a freed vnode.  We abort if anyone picks up a reference
  864  * before we actually vgone().  This function must be called with the vnode
  865  * held to prevent the vnode from being returned to the free list midway
  866  * through vgone().
  867  */
  868 static int
  869 vtryrecycle(struct vnode *vp)
  870 {
  871         struct mount *vnmp;
  872 
  873         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  874         VNASSERT(vp->v_holdcnt, vp,
  875             ("vtryrecycle: Recycling vp %p without a reference.", vp));
  876         /*
  877          * This vnode may found and locked via some other list, if so we
  878          * can't recycle it yet.
  879          */
  880         if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
  881                 CTR2(KTR_VFS,
  882                     "%s: impossible to recycle, vp %p lock is already held",
  883                     __func__, vp);
  884                 return (EWOULDBLOCK);
  885         }
  886         /*
  887          * Don't recycle if its filesystem is being suspended.
  888          */
  889         if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
  890                 VOP_UNLOCK(vp, 0);
  891                 CTR2(KTR_VFS,
  892                     "%s: impossible to recycle, cannot start the write for %p",
  893                     __func__, vp);
  894                 return (EBUSY);
  895         }
  896         /*
  897          * If we got this far, we need to acquire the interlock and see if
  898          * anyone picked up this vnode from another list.  If not, we will
  899          * mark it with DOOMED via vgonel() so that anyone who does find it
  900          * will skip over it.
  901          */
  902         VI_LOCK(vp);
  903         if (vp->v_usecount) {
  904                 VOP_UNLOCK(vp, LK_INTERLOCK);
  905                 vn_finished_write(vnmp);
  906                 CTR2(KTR_VFS,
  907                     "%s: impossible to recycle, %p is already referenced",
  908                     __func__, vp);
  909                 return (EBUSY);
  910         }
  911         if ((vp->v_iflag & VI_DOOMED) == 0)
  912                 vgonel(vp);
  913         VOP_UNLOCK(vp, LK_INTERLOCK);
  914         vn_finished_write(vnmp);
  915         return (0);
  916 }
  917 
  918 /*
  919  * Return the next vnode from the free list.
  920  */
  921 int
  922 getnewvnode(const char *tag, struct mount *mp, struct vop_vector *vops,
  923     struct vnode **vpp)
  924 {
  925         struct vnode *vp = NULL;
  926         struct bufobj *bo;
  927 
  928         CTR3(KTR_VFS, "%s: mp %p with tag %s", __func__, mp, tag);
  929         mtx_lock(&vnode_free_list_mtx);
  930         /*
  931          * Lend our context to reclaim vnodes if they've exceeded the max.
  932          */
  933         if (freevnodes > wantfreevnodes)
  934                 vnlru_free(1);
  935         /*
  936          * Wait for available vnodes.
  937          */
  938         if (numvnodes > desiredvnodes) {
  939                 if (mp != NULL && (mp->mnt_kern_flag & MNTK_SUSPEND)) {
  940                         /*
  941                          * File system is beeing suspended, we cannot risk a
  942                          * deadlock here, so allocate new vnode anyway.
  943                          */
  944                         if (freevnodes > wantfreevnodes)
  945                                 vnlru_free(freevnodes - wantfreevnodes);
  946                         goto alloc;
  947                 }
  948                 if (vnlruproc_sig == 0) {
  949                         vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
  950                         wakeup(vnlruproc);
  951                 }
  952                 msleep(&vnlruproc_sig, &vnode_free_list_mtx, PVFS,
  953                     "vlruwk", hz);
  954 #if 0   /* XXX Not all VFS_VGET/ffs_vget callers check returns. */
  955                 if (numvnodes > desiredvnodes) {
  956                         mtx_unlock(&vnode_free_list_mtx);
  957                         return (ENFILE);
  958                 }
  959 #endif
  960         }
  961 alloc:
  962         numvnodes++;
  963         mtx_unlock(&vnode_free_list_mtx);
  964         vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
  965         /*
  966          * Setup locks.
  967          */
  968         vp->v_vnlock = &vp->v_lock;
  969         mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
  970         /*
  971          * By default, don't allow shared locks unless filesystems
  972          * opt-in.
  973          */
  974         lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOSHARE);
  975         /*
  976          * Initialize bufobj.
  977          */
  978         bo = &vp->v_bufobj;
  979         bo->__bo_vnode = vp;
  980         mtx_init(BO_MTX(bo), "bufobj interlock", NULL, MTX_DEF);
  981         bo->bo_ops = &buf_ops_bio;
  982         bo->bo_private = vp;
  983         TAILQ_INIT(&bo->bo_clean.bv_hd);
  984         TAILQ_INIT(&bo->bo_dirty.bv_hd);
  985         /*
  986          * Initialize namecache.
  987          */
  988         LIST_INIT(&vp->v_cache_src);
  989         TAILQ_INIT(&vp->v_cache_dst);
  990         /*
  991          * Finalize various vnode identity bits.
  992          */
  993         vp->v_type = VNON;
  994         vp->v_tag = tag;
  995         vp->v_op = vops;
  996         v_incr_usecount(vp);
  997         vp->v_data = 0;
  998 #ifdef MAC
  999         mac_vnode_init(vp);
 1000         if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
 1001                 mac_vnode_associate_singlelabel(mp, vp);
 1002         else if (mp == NULL && vops != &dead_vnodeops)
 1003                 printf("NULL mp in getnewvnode()\n");
 1004 #endif
 1005         if (mp != NULL) {
 1006                 bo->bo_bsize = mp->mnt_stat.f_iosize;
 1007                 if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
 1008                         vp->v_vflag |= VV_NOKNOTE;
 1009         }
 1010 
 1011         *vpp = vp;
 1012         return (0);
 1013 }
 1014 
 1015 /*
 1016  * Delete from old mount point vnode list, if on one.
 1017  */
 1018 static void
 1019 delmntque(struct vnode *vp)
 1020 {
 1021         struct mount *mp;
 1022 
 1023         mp = vp->v_mount;
 1024         if (mp == NULL)
 1025                 return;
 1026         MNT_ILOCK(mp);
 1027         vp->v_mount = NULL;
 1028         VNASSERT(mp->mnt_nvnodelistsize > 0, vp,
 1029                 ("bad mount point vnode list size"));
 1030         TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1031         mp->mnt_nvnodelistsize--;
 1032         MNT_REL(mp);
 1033         MNT_IUNLOCK(mp);
 1034 }
 1035 
 1036 static void
 1037 insmntque_stddtr(struct vnode *vp, void *dtr_arg)
 1038 {
 1039 
 1040         vp->v_data = NULL;
 1041         vp->v_op = &dead_vnodeops;
 1042         /* XXX non mp-safe fs may still call insmntque with vnode
 1043            unlocked */
 1044         if (!VOP_ISLOCKED(vp))
 1045                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1046         vgone(vp);
 1047         vput(vp);
 1048 }
 1049 
 1050 /*
 1051  * Insert into list of vnodes for the new mount point, if available.
 1052  */
 1053 int
 1054 insmntque1(struct vnode *vp, struct mount *mp,
 1055         void (*dtr)(struct vnode *, void *), void *dtr_arg)
 1056 {
 1057         int locked;
 1058 
 1059         KASSERT(vp->v_mount == NULL,
 1060                 ("insmntque: vnode already on per mount vnode list"));
 1061         VNASSERT(mp != NULL, vp, ("Don't call insmntque(foo, NULL)"));
 1062 #ifdef DEBUG_VFS_LOCKS
 1063         if (!VFS_NEEDSGIANT(mp))
 1064                 ASSERT_VOP_ELOCKED(vp,
 1065                     "insmntque: mp-safe fs and non-locked vp");
 1066 #endif
 1067         MNT_ILOCK(mp);
 1068         if ((mp->mnt_kern_flag & MNTK_NOINSMNTQ) != 0 &&
 1069             ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0 ||
 1070              mp->mnt_nvnodelistsize == 0)) {
 1071                 locked = VOP_ISLOCKED(vp);
 1072                 if (!locked || (locked == LK_EXCLUSIVE &&
 1073                      (vp->v_vflag & VV_FORCEINSMQ) == 0)) {
 1074                         MNT_IUNLOCK(mp);
 1075                         if (dtr != NULL)
 1076                                 dtr(vp, dtr_arg);
 1077                         return (EBUSY);
 1078                 }
 1079         }
 1080         vp->v_mount = mp;
 1081         MNT_REF(mp);
 1082         TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1083         VNASSERT(mp->mnt_nvnodelistsize >= 0, vp,
 1084                 ("neg mount point vnode list size"));
 1085         mp->mnt_nvnodelistsize++;
 1086         MNT_IUNLOCK(mp);
 1087         return (0);
 1088 }
 1089 
 1090 int
 1091 insmntque(struct vnode *vp, struct mount *mp)
 1092 {
 1093 
 1094         return (insmntque1(vp, mp, insmntque_stddtr, NULL));
 1095 }
 1096 
 1097 /*
 1098  * Flush out and invalidate all buffers associated with a bufobj
 1099  * Called with the underlying object locked.
 1100  */
 1101 int
 1102 bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo)
 1103 {
 1104         int error;
 1105 
 1106         BO_LOCK(bo);
 1107         if (flags & V_SAVE) {
 1108                 error = bufobj_wwait(bo, slpflag, slptimeo);
 1109                 if (error) {
 1110                         BO_UNLOCK(bo);
 1111                         return (error);
 1112                 }
 1113                 if (bo->bo_dirty.bv_cnt > 0) {
 1114                         BO_UNLOCK(bo);
 1115                         if ((error = BO_SYNC(bo, MNT_WAIT)) != 0)
 1116                                 return (error);
 1117                         /*
 1118                          * XXX We could save a lock/unlock if this was only
 1119                          * enabled under INVARIANTS
 1120                          */
 1121                         BO_LOCK(bo);
 1122                         if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
 1123                                 panic("vinvalbuf: dirty bufs");
 1124                 }
 1125         }
 1126         /*
 1127          * If you alter this loop please notice that interlock is dropped and
 1128          * reacquired in flushbuflist.  Special care is needed to ensure that
 1129          * no race conditions occur from this.
 1130          */
 1131         do {
 1132                 error = flushbuflist(&bo->bo_clean,
 1133                     flags, bo, slpflag, slptimeo);
 1134                 if (error == 0)
 1135                         error = flushbuflist(&bo->bo_dirty,
 1136                             flags, bo, slpflag, slptimeo);
 1137                 if (error != 0 && error != EAGAIN) {
 1138                         BO_UNLOCK(bo);
 1139                         return (error);
 1140                 }
 1141         } while (error != 0);
 1142 
 1143         /*
 1144          * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
 1145          * have write I/O in-progress but if there is a VM object then the
 1146          * VM object can also have read-I/O in-progress.
 1147          */
 1148         do {
 1149                 bufobj_wwait(bo, 0, 0);
 1150                 BO_UNLOCK(bo);
 1151                 if (bo->bo_object != NULL) {
 1152                         VM_OBJECT_LOCK(bo->bo_object);
 1153                         vm_object_pip_wait(bo->bo_object, "bovlbx");
 1154                         VM_OBJECT_UNLOCK(bo->bo_object);
 1155                 }
 1156                 BO_LOCK(bo);
 1157         } while (bo->bo_numoutput > 0);
 1158         BO_UNLOCK(bo);
 1159 
 1160         /*
 1161          * Destroy the copy in the VM cache, too.
 1162          */
 1163         if (bo->bo_object != NULL && (flags & (V_ALT | V_NORMAL)) == 0) {
 1164                 VM_OBJECT_LOCK(bo->bo_object);
 1165                 vm_object_page_remove(bo->bo_object, 0, 0,
 1166                         (flags & V_SAVE) ? TRUE : FALSE);
 1167                 VM_OBJECT_UNLOCK(bo->bo_object);
 1168         }
 1169 
 1170 #ifdef INVARIANTS
 1171         BO_LOCK(bo);
 1172         if ((flags & (V_ALT | V_NORMAL)) == 0 &&
 1173             (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
 1174                 panic("vinvalbuf: flush failed");
 1175         BO_UNLOCK(bo);
 1176 #endif
 1177         return (0);
 1178 }
 1179 
 1180 /*
 1181  * Flush out and invalidate all buffers associated with a vnode.
 1182  * Called with the underlying object locked.
 1183  */
 1184 int
 1185 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
 1186 {
 1187 
 1188         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 1189         ASSERT_VOP_LOCKED(vp, "vinvalbuf");
 1190         return (bufobj_invalbuf(&vp->v_bufobj, flags, slpflag, slptimeo));
 1191 }
 1192 
 1193 /*
 1194  * Flush out buffers on the specified list.
 1195  *
 1196  */
 1197 static int
 1198 flushbuflist( struct bufv *bufv, int flags, struct bufobj *bo, int slpflag,
 1199     int slptimeo)
 1200 {
 1201         struct buf *bp, *nbp;
 1202         int retval, error;
 1203         daddr_t lblkno;
 1204         b_xflags_t xflags;
 1205 
 1206         ASSERT_BO_LOCKED(bo);
 1207 
 1208         retval = 0;
 1209         TAILQ_FOREACH_SAFE(bp, &bufv->bv_hd, b_bobufs, nbp) {
 1210                 if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
 1211                     ((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
 1212                         continue;
 1213                 }
 1214                 lblkno = 0;
 1215                 xflags = 0;
 1216                 if (nbp != NULL) {
 1217                         lblkno = nbp->b_lblkno;
 1218                         xflags = nbp->b_xflags &
 1219                                 (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN);
 1220                 }
 1221                 retval = EAGAIN;
 1222                 error = BUF_TIMELOCK(bp,
 1223                     LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, BO_MTX(bo),
 1224                     "flushbuf", slpflag, slptimeo);
 1225                 if (error) {
 1226                         BO_LOCK(bo);
 1227                         return (error != ENOLCK ? error : EAGAIN);
 1228                 }
 1229                 KASSERT(bp->b_bufobj == bo,
 1230                     ("bp %p wrong b_bufobj %p should be %p",
 1231                     bp, bp->b_bufobj, bo));
 1232                 if (bp->b_bufobj != bo) {       /* XXX: necessary ? */
 1233                         BUF_UNLOCK(bp);
 1234                         BO_LOCK(bo);
 1235                         return (EAGAIN);
 1236                 }
 1237                 /*
 1238                  * XXX Since there are no node locks for NFS, I
 1239                  * believe there is a slight chance that a delayed
 1240                  * write will occur while sleeping just above, so
 1241                  * check for it.
 1242                  */
 1243                 if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
 1244                     (flags & V_SAVE)) {
 1245                         bremfree(bp);
 1246                         bp->b_flags |= B_ASYNC;
 1247                         bwrite(bp);
 1248                         BO_LOCK(bo);
 1249                         return (EAGAIN);        /* XXX: why not loop ? */
 1250                 }
 1251                 bremfree(bp);
 1252                 bp->b_flags |= (B_INVAL | B_RELBUF);
 1253                 bp->b_flags &= ~B_ASYNC;
 1254                 brelse(bp);
 1255                 BO_LOCK(bo);
 1256                 if (nbp != NULL &&
 1257                     (nbp->b_bufobj != bo ||
 1258                      nbp->b_lblkno != lblkno ||
 1259                      (nbp->b_xflags &
 1260                       (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN)) != xflags))
 1261                         break;                  /* nbp invalid */
 1262         }
 1263         return (retval);
 1264 }
 1265 
 1266 /*
 1267  * Truncate a file's buffer and pages to a specified length.  This
 1268  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
 1269  * sync activity.
 1270  */
 1271 int
 1272 vtruncbuf(struct vnode *vp, struct ucred *cred, struct thread *td,
 1273     off_t length, int blksize)
 1274 {
 1275         struct buf *bp, *nbp;
 1276         int anyfreed;
 1277         int trunclbn;
 1278         struct bufobj *bo;
 1279 
 1280         CTR5(KTR_VFS, "%s: vp %p with cred %p and block %d:%ju", __func__,
 1281             vp, cred, blksize, (uintmax_t)length);
 1282 
 1283         /*
 1284          * Round up to the *next* lbn.
 1285          */
 1286         trunclbn = (length + blksize - 1) / blksize;
 1287 
 1288         ASSERT_VOP_LOCKED(vp, "vtruncbuf");
 1289 restart:
 1290         bo = &vp->v_bufobj;
 1291         BO_LOCK(bo);
 1292         anyfreed = 1;
 1293         for (;anyfreed;) {
 1294                 anyfreed = 0;
 1295                 TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
 1296                         if (bp->b_lblkno < trunclbn)
 1297                                 continue;
 1298                         if (BUF_LOCK(bp,
 1299                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1300                             BO_MTX(bo)) == ENOLCK)
 1301                                 goto restart;
 1302 
 1303                         bremfree(bp);
 1304                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1305                         bp->b_flags &= ~B_ASYNC;
 1306                         brelse(bp);
 1307                         anyfreed = 1;
 1308 
 1309                         if (nbp != NULL &&
 1310                             (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
 1311                             (nbp->b_vp != vp) ||
 1312                             (nbp->b_flags & B_DELWRI))) {
 1313                                 goto restart;
 1314                         }
 1315                         BO_LOCK(bo);
 1316                 }
 1317 
 1318                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1319                         if (bp->b_lblkno < trunclbn)
 1320                                 continue;
 1321                         if (BUF_LOCK(bp,
 1322                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1323                             BO_MTX(bo)) == ENOLCK)
 1324                                 goto restart;
 1325                         bremfree(bp);
 1326                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1327                         bp->b_flags &= ~B_ASYNC;
 1328                         brelse(bp);
 1329                         anyfreed = 1;
 1330                         if (nbp != NULL &&
 1331                             (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
 1332                             (nbp->b_vp != vp) ||
 1333                             (nbp->b_flags & B_DELWRI) == 0)) {
 1334                                 goto restart;
 1335                         }
 1336                         BO_LOCK(bo);
 1337                 }
 1338         }
 1339 
 1340         if (length > 0) {
 1341 restartsync:
 1342                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1343                         if (bp->b_lblkno > 0)
 1344                                 continue;
 1345                         /*
 1346                          * Since we hold the vnode lock this should only
 1347                          * fail if we're racing with the buf daemon.
 1348                          */
 1349                         if (BUF_LOCK(bp,
 1350                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1351                             BO_MTX(bo)) == ENOLCK) {
 1352                                 goto restart;
 1353                         }
 1354                         VNASSERT((bp->b_flags & B_DELWRI), vp,
 1355                             ("buf(%p) on dirty queue without DELWRI", bp));
 1356 
 1357                         bremfree(bp);
 1358                         bawrite(bp);
 1359                         BO_LOCK(bo);
 1360                         goto restartsync;
 1361                 }
 1362         }
 1363 
 1364         bufobj_wwait(bo, 0, 0);
 1365         BO_UNLOCK(bo);
 1366         vnode_pager_setsize(vp, length);
 1367 
 1368         return (0);
 1369 }
 1370 
 1371 /*
 1372  * buf_splay() - splay tree core for the clean/dirty list of buffers in
 1373  *               a vnode.
 1374  *
 1375  *      NOTE: We have to deal with the special case of a background bitmap
 1376  *      buffer, a situation where two buffers will have the same logical
 1377  *      block offset.  We want (1) only the foreground buffer to be accessed
 1378  *      in a lookup and (2) must differentiate between the foreground and
 1379  *      background buffer in the splay tree algorithm because the splay
 1380  *      tree cannot normally handle multiple entities with the same 'index'.
 1381  *      We accomplish this by adding differentiating flags to the splay tree's
 1382  *      numerical domain.
 1383  */
 1384 static
 1385 struct buf *
 1386 buf_splay(daddr_t lblkno, b_xflags_t xflags, struct buf *root)
 1387 {
 1388         struct buf dummy;
 1389         struct buf *lefttreemax, *righttreemin, *y;
 1390 
 1391         if (root == NULL)
 1392                 return (NULL);
 1393         lefttreemax = righttreemin = &dummy;
 1394         for (;;) {
 1395                 if (lblkno < root->b_lblkno ||
 1396                     (lblkno == root->b_lblkno &&
 1397                     (xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1398                         if ((y = root->b_left) == NULL)
 1399                                 break;
 1400                         if (lblkno < y->b_lblkno) {
 1401                                 /* Rotate right. */
 1402                                 root->b_left = y->b_right;
 1403                                 y->b_right = root;
 1404                                 root = y;
 1405                                 if ((y = root->b_left) == NULL)
 1406                                         break;
 1407                         }
 1408                         /* Link into the new root's right tree. */
 1409                         righttreemin->b_left = root;
 1410                         righttreemin = root;
 1411                 } else if (lblkno > root->b_lblkno ||
 1412                     (lblkno == root->b_lblkno &&
 1413                     (xflags & BX_BKGRDMARKER) > (root->b_xflags & BX_BKGRDMARKER))) {
 1414                         if ((y = root->b_right) == NULL)
 1415                                 break;
 1416                         if (lblkno > y->b_lblkno) {
 1417                                 /* Rotate left. */
 1418                                 root->b_right = y->b_left;
 1419                                 y->b_left = root;
 1420                                 root = y;
 1421                                 if ((y = root->b_right) == NULL)
 1422                                         break;
 1423                         }
 1424                         /* Link into the new root's left tree. */
 1425                         lefttreemax->b_right = root;
 1426                         lefttreemax = root;
 1427                 } else {
 1428                         break;
 1429                 }
 1430                 root = y;
 1431         }
 1432         /* Assemble the new root. */
 1433         lefttreemax->b_right = root->b_left;
 1434         righttreemin->b_left = root->b_right;
 1435         root->b_left = dummy.b_right;
 1436         root->b_right = dummy.b_left;
 1437         return (root);
 1438 }
 1439 
 1440 static void
 1441 buf_vlist_remove(struct buf *bp)
 1442 {
 1443         struct buf *root;
 1444         struct bufv *bv;
 1445 
 1446         KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
 1447         ASSERT_BO_LOCKED(bp->b_bufobj);
 1448         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) !=
 1449             (BX_VNDIRTY|BX_VNCLEAN),
 1450             ("buf_vlist_remove: Buf %p is on two lists", bp));
 1451         if (bp->b_xflags & BX_VNDIRTY)
 1452                 bv = &bp->b_bufobj->bo_dirty;
 1453         else
 1454                 bv = &bp->b_bufobj->bo_clean;
 1455         if (bp != bv->bv_root) {
 1456                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1457                 KASSERT(root == bp, ("splay lookup failed in remove"));
 1458         }
 1459         if (bp->b_left == NULL) {
 1460                 root = bp->b_right;
 1461         } else {
 1462                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
 1463                 root->b_right = bp->b_right;
 1464         }
 1465         bv->bv_root = root;
 1466         TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
 1467         bv->bv_cnt--;
 1468         bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
 1469 }
 1470 
 1471 /*
 1472  * Add the buffer to the sorted clean or dirty block list using a
 1473  * splay tree algorithm.
 1474  *
 1475  * NOTE: xflags is passed as a constant, optimizing this inline function!
 1476  */
 1477 static void
 1478 buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
 1479 {
 1480         struct buf *root;
 1481         struct bufv *bv;
 1482 
 1483         ASSERT_BO_LOCKED(bo);
 1484         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
 1485             ("buf_vlist_add: Buf %p has existing xflags %d", bp, bp->b_xflags));
 1486         bp->b_xflags |= xflags;
 1487         if (xflags & BX_VNDIRTY)
 1488                 bv = &bo->bo_dirty;
 1489         else
 1490                 bv = &bo->bo_clean;
 1491 
 1492         root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1493         if (root == NULL) {
 1494                 bp->b_left = NULL;
 1495                 bp->b_right = NULL;
 1496                 TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
 1497         } else if (bp->b_lblkno < root->b_lblkno ||
 1498             (bp->b_lblkno == root->b_lblkno &&
 1499             (bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1500                 bp->b_left = root->b_left;
 1501                 bp->b_right = root;
 1502                 root->b_left = NULL;
 1503                 TAILQ_INSERT_BEFORE(root, bp, b_bobufs);
 1504         } else {
 1505                 bp->b_right = root->b_right;
 1506                 bp->b_left = root;
 1507                 root->b_right = NULL;
 1508                 TAILQ_INSERT_AFTER(&bv->bv_hd, root, bp, b_bobufs);
 1509         }
 1510         bv->bv_cnt++;
 1511         bv->bv_root = bp;
 1512 }
 1513 
 1514 /*
 1515  * Lookup a buffer using the splay tree.  Note that we specifically avoid
 1516  * shadow buffers used in background bitmap writes.
 1517  *
 1518  * This code isn't quite efficient as it could be because we are maintaining
 1519  * two sorted lists and do not know which list the block resides in.
 1520  *
 1521  * During a "make buildworld" the desired buffer is found at one of
 1522  * the roots more than 60% of the time.  Thus, checking both roots
 1523  * before performing either splay eliminates unnecessary splays on the
 1524  * first tree splayed.
 1525  */
 1526 struct buf *
 1527 gbincore(struct bufobj *bo, daddr_t lblkno)
 1528 {
 1529         struct buf *bp;
 1530 
 1531         ASSERT_BO_LOCKED(bo);
 1532         if ((bp = bo->bo_clean.bv_root) != NULL &&
 1533             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1534                 return (bp);
 1535         if ((bp = bo->bo_dirty.bv_root) != NULL &&
 1536             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1537                 return (bp);
 1538         if ((bp = bo->bo_clean.bv_root) != NULL) {
 1539                 bo->bo_clean.bv_root = bp = buf_splay(lblkno, 0, bp);
 1540                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1541                         return (bp);
 1542         }
 1543         if ((bp = bo->bo_dirty.bv_root) != NULL) {
 1544                 bo->bo_dirty.bv_root = bp = buf_splay(lblkno, 0, bp);
 1545                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1546                         return (bp);
 1547         }
 1548         return (NULL);
 1549 }
 1550 
 1551 /*
 1552  * Associate a buffer with a vnode.
 1553  */
 1554 void
 1555 bgetvp(struct vnode *vp, struct buf *bp)
 1556 {
 1557         struct bufobj *bo;
 1558 
 1559         bo = &vp->v_bufobj;
 1560         ASSERT_BO_LOCKED(bo);
 1561         VNASSERT(bp->b_vp == NULL, bp->b_vp, ("bgetvp: not free"));
 1562 
 1563         CTR3(KTR_BUF, "bgetvp(%p) vp %p flags %X", bp, vp, bp->b_flags);
 1564         VNASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0, vp,
 1565             ("bgetvp: bp already attached! %p", bp));
 1566 
 1567         vhold(vp);
 1568         if (VFS_NEEDSGIANT(vp->v_mount) || bo->bo_flag & BO_NEEDSGIANT)
 1569                 bp->b_flags |= B_NEEDSGIANT;
 1570         bp->b_vp = vp;
 1571         bp->b_bufobj = bo;
 1572         /*
 1573          * Insert onto list for new vnode.
 1574          */
 1575         buf_vlist_add(bp, bo, BX_VNCLEAN);
 1576 }
 1577 
 1578 /*
 1579  * Disassociate a buffer from a vnode.
 1580  */
 1581 void
 1582 brelvp(struct buf *bp)
 1583 {
 1584         struct bufobj *bo;
 1585         struct vnode *vp;
 1586 
 1587         CTR3(KTR_BUF, "brelvp(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
 1588         KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
 1589 
 1590         /*
 1591          * Delete from old vnode list, if on one.
 1592          */
 1593         vp = bp->b_vp;          /* XXX */
 1594         bo = bp->b_bufobj;
 1595         BO_LOCK(bo);
 1596         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1597                 buf_vlist_remove(bp);
 1598         else
 1599                 panic("brelvp: Buffer %p not on queue.", bp);
 1600         if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 1601                 bo->bo_flag &= ~BO_ONWORKLST;
 1602                 mtx_lock(&sync_mtx);
 1603                 LIST_REMOVE(bo, bo_synclist);
 1604                 syncer_worklist_len--;
 1605                 mtx_unlock(&sync_mtx);
 1606         }
 1607         bp->b_flags &= ~B_NEEDSGIANT;
 1608         bp->b_vp = NULL;
 1609         bp->b_bufobj = NULL;
 1610         BO_UNLOCK(bo);
 1611         vdrop(vp);
 1612 }
 1613 
 1614 /*
 1615  * Add an item to the syncer work queue.
 1616  */
 1617 static void
 1618 vn_syncer_add_to_worklist(struct bufobj *bo, int delay)
 1619 {
 1620         int queue, slot;
 1621 
 1622         ASSERT_BO_LOCKED(bo);
 1623 
 1624         mtx_lock(&sync_mtx);
 1625         if (bo->bo_flag & BO_ONWORKLST)
 1626                 LIST_REMOVE(bo, bo_synclist);
 1627         else {
 1628                 bo->bo_flag |= BO_ONWORKLST;
 1629                 syncer_worklist_len++;
 1630         }
 1631 
 1632         if (delay > syncer_maxdelay - 2)
 1633                 delay = syncer_maxdelay - 2;
 1634         slot = (syncer_delayno + delay) & syncer_mask;
 1635 
 1636         queue = VFS_NEEDSGIANT(bo->__bo_vnode->v_mount) ? WI_GIANTQ :
 1637             WI_MPSAFEQ;
 1638         LIST_INSERT_HEAD(&syncer_workitem_pending[queue][slot], bo,
 1639             bo_synclist);
 1640         mtx_unlock(&sync_mtx);
 1641 }
 1642 
 1643 static int
 1644 sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
 1645 {
 1646         int error, len;
 1647 
 1648         mtx_lock(&sync_mtx);
 1649         len = syncer_worklist_len - sync_vnode_count;
 1650         mtx_unlock(&sync_mtx);
 1651         error = SYSCTL_OUT(req, &len, sizeof(len));
 1652         return (error);
 1653 }
 1654 
 1655 SYSCTL_PROC(_vfs, OID_AUTO, worklist_len, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
 1656     sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
 1657 
 1658 static struct proc *updateproc;
 1659 static void sched_sync(void);
 1660 static struct kproc_desc up_kp = {
 1661         "syncer",
 1662         sched_sync,
 1663         &updateproc
 1664 };
 1665 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp);
 1666 
 1667 static int
 1668 sync_vnode(struct synclist *slp, struct bufobj **bo, struct thread *td)
 1669 {
 1670         struct vnode *vp;
 1671         struct mount *mp;
 1672 
 1673         *bo = LIST_FIRST(slp);
 1674         if (*bo == NULL)
 1675                 return (0);
 1676         vp = (*bo)->__bo_vnode; /* XXX */
 1677         if (VOP_ISLOCKED(vp) != 0 || VI_TRYLOCK(vp) == 0)
 1678                 return (1);
 1679         /*
 1680          * We use vhold in case the vnode does not
 1681          * successfully sync.  vhold prevents the vnode from
 1682          * going away when we unlock the sync_mtx so that
 1683          * we can acquire the vnode interlock.
 1684          */
 1685         vholdl(vp);
 1686         mtx_unlock(&sync_mtx);
 1687         VI_UNLOCK(vp);
 1688         if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
 1689                 vdrop(vp);
 1690                 mtx_lock(&sync_mtx);
 1691                 return (*bo == LIST_FIRST(slp));
 1692         }
 1693         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1694         (void) VOP_FSYNC(vp, MNT_LAZY, td);
 1695         VOP_UNLOCK(vp, 0);
 1696         vn_finished_write(mp);
 1697         BO_LOCK(*bo);
 1698         if (((*bo)->bo_flag & BO_ONWORKLST) != 0) {
 1699                 /*
 1700                  * Put us back on the worklist.  The worklist
 1701                  * routine will remove us from our current
 1702                  * position and then add us back in at a later
 1703                  * position.
 1704                  */
 1705                 vn_syncer_add_to_worklist(*bo, syncdelay);
 1706         }
 1707         BO_UNLOCK(*bo);
 1708         vdrop(vp);
 1709         mtx_lock(&sync_mtx);
 1710         return (0);
 1711 }
 1712 
 1713 /*
 1714  * System filesystem synchronizer daemon.
 1715  */
 1716 static void
 1717 sched_sync(void)
 1718 {
 1719         struct synclist *gnext, *next;
 1720         struct synclist *gslp, *slp;
 1721         struct bufobj *bo;
 1722         long starttime;
 1723         struct thread *td = curthread;
 1724         int last_work_seen;
 1725         int net_worklist_len;
 1726         int syncer_final_iter;
 1727         int first_printf;
 1728         int error;
 1729 
 1730         last_work_seen = 0;
 1731         syncer_final_iter = 0;
 1732         first_printf = 1;
 1733         syncer_state = SYNCER_RUNNING;
 1734         starttime = time_uptime;
 1735         td->td_pflags |= TDP_NORUNNINGBUF;
 1736 
 1737         EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
 1738             SHUTDOWN_PRI_LAST);
 1739 
 1740         mtx_lock(&sync_mtx);
 1741         for (;;) {
 1742                 if (syncer_state == SYNCER_FINAL_DELAY &&
 1743                     syncer_final_iter == 0) {
 1744                         mtx_unlock(&sync_mtx);
 1745                         kproc_suspend_check(td->td_proc);
 1746                         mtx_lock(&sync_mtx);
 1747                 }
 1748                 net_worklist_len = syncer_worklist_len - sync_vnode_count;
 1749                 if (syncer_state != SYNCER_RUNNING &&
 1750                     starttime != time_uptime) {
 1751                         if (first_printf) {
 1752                                 printf("\nSyncing disks, vnodes remaining...");
 1753                                 first_printf = 0;
 1754                         }
 1755                         printf("%d ", net_worklist_len);
 1756                 }
 1757                 starttime = time_uptime;
 1758 
 1759                 /*
 1760                  * Push files whose dirty time has expired.  Be careful
 1761                  * of interrupt race on slp queue.
 1762                  *
 1763                  * Skip over empty worklist slots when shutting down.
 1764                  */
 1765                 do {
 1766                         slp = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1767                         gslp = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1768                         syncer_delayno += 1;
 1769                         if (syncer_delayno == syncer_maxdelay)
 1770                                 syncer_delayno = 0;
 1771                         next = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1772                         gnext = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1773                         /*
 1774                          * If the worklist has wrapped since the
 1775                          * it was emptied of all but syncer vnodes,
 1776                          * switch to the FINAL_DELAY state and run
 1777                          * for one more second.
 1778                          */
 1779                         if (syncer_state == SYNCER_SHUTTING_DOWN &&
 1780                             net_worklist_len == 0 &&
 1781                             last_work_seen == syncer_delayno) {
 1782                                 syncer_state = SYNCER_FINAL_DELAY;
 1783                                 syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
 1784                         }
 1785                 } while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
 1786                     LIST_EMPTY(gslp) && syncer_worklist_len > 0);
 1787 
 1788                 /*
 1789                  * Keep track of the last time there was anything
 1790                  * on the worklist other than syncer vnodes.
 1791                  * Return to the SHUTTING_DOWN state if any
 1792                  * new work appears.
 1793                  */
 1794                 if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
 1795                         last_work_seen = syncer_delayno;
 1796                 if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
 1797                         syncer_state = SYNCER_SHUTTING_DOWN;
 1798                 while (!LIST_EMPTY(slp)) {
 1799                         error = sync_vnode(slp, &bo, td);
 1800                         if (error == 1) {
 1801                                 LIST_REMOVE(bo, bo_synclist);
 1802                                 LIST_INSERT_HEAD(next, bo, bo_synclist);
 1803                                 continue;
 1804                         }
 1805                 }
 1806                 if (!LIST_EMPTY(gslp)) {
 1807                         mtx_unlock(&sync_mtx);
 1808                         mtx_lock(&Giant);
 1809                         mtx_lock(&sync_mtx);
 1810                         while (!LIST_EMPTY(gslp)) {
 1811                                 error = sync_vnode(gslp, &bo, td);
 1812                                 if (error == 1) {
 1813                                         LIST_REMOVE(bo, bo_synclist);
 1814                                         LIST_INSERT_HEAD(gnext, bo,
 1815                                             bo_synclist);
 1816                                         continue;
 1817                                 }
 1818                         }
 1819                         mtx_unlock(&Giant);
 1820                 }
 1821                 if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
 1822                         syncer_final_iter--;
 1823                 /*
 1824                  * The variable rushjob allows the kernel to speed up the
 1825                  * processing of the filesystem syncer process. A rushjob
 1826                  * value of N tells the filesystem syncer to process the next
 1827                  * N seconds worth of work on its queue ASAP. Currently rushjob
 1828                  * is used by the soft update code to speed up the filesystem
 1829                  * syncer process when the incore state is getting so far
 1830                  * ahead of the disk that the kernel memory pool is being
 1831                  * threatened with exhaustion.
 1832                  */
 1833                 if (rushjob > 0) {
 1834                         rushjob -= 1;
 1835                         continue;
 1836                 }
 1837                 /*
 1838                  * Just sleep for a short period of time between
 1839                  * iterations when shutting down to allow some I/O
 1840                  * to happen.
 1841                  *
 1842                  * If it has taken us less than a second to process the
 1843                  * current work, then wait. Otherwise start right over
 1844                  * again. We can still lose time if any single round
 1845                  * takes more than two seconds, but it does not really
 1846                  * matter as we are just trying to generally pace the
 1847                  * filesystem activity.
 1848                  */
 1849                 if (syncer_state != SYNCER_RUNNING)
 1850                         cv_timedwait(&sync_wakeup, &sync_mtx,
 1851                             hz / SYNCER_SHUTDOWN_SPEEDUP);
 1852                 else if (time_uptime == starttime)
 1853                         cv_timedwait(&sync_wakeup, &sync_mtx, hz);
 1854         }
 1855 }
 1856 
 1857 /*
 1858  * Request the syncer daemon to speed up its work.
 1859  * We never push it to speed up more than half of its
 1860  * normal turn time, otherwise it could take over the cpu.
 1861  */
 1862 int
 1863 speedup_syncer(void)
 1864 {
 1865         int ret = 0;
 1866 
 1867         mtx_lock(&sync_mtx);
 1868         if (rushjob < syncdelay / 2) {
 1869                 rushjob += 1;
 1870                 stat_rush_requests += 1;
 1871                 ret = 1;
 1872         }
 1873         mtx_unlock(&sync_mtx);
 1874         cv_broadcast(&sync_wakeup);
 1875         return (ret);
 1876 }
 1877 
 1878 /*
 1879  * Tell the syncer to speed up its work and run though its work
 1880  * list several times, then tell it to shut down.
 1881  */
 1882 static void
 1883 syncer_shutdown(void *arg, int howto)
 1884 {
 1885 
 1886         if (howto & RB_NOSYNC)
 1887                 return;
 1888         mtx_lock(&sync_mtx);
 1889         syncer_state = SYNCER_SHUTTING_DOWN;
 1890         rushjob = 0;
 1891         mtx_unlock(&sync_mtx);
 1892         cv_broadcast(&sync_wakeup);
 1893         kproc_shutdown(arg, howto);
 1894 }
 1895 
 1896 /*
 1897  * Reassign a buffer from one vnode to another.
 1898  * Used to assign file specific control information
 1899  * (indirect blocks) to the vnode to which they belong.
 1900  */
 1901 void
 1902 reassignbuf(struct buf *bp)
 1903 {
 1904         struct vnode *vp;
 1905         struct bufobj *bo;
 1906         int delay;
 1907 #ifdef INVARIANTS
 1908         struct bufv *bv;
 1909 #endif
 1910 
 1911         vp = bp->b_vp;
 1912         bo = bp->b_bufobj;
 1913         ++reassignbufcalls;
 1914 
 1915         CTR3(KTR_BUF, "reassignbuf(%p) vp %p flags %X",
 1916             bp, bp->b_vp, bp->b_flags);
 1917         /*
 1918          * B_PAGING flagged buffers cannot be reassigned because their vp
 1919          * is not fully linked in.
 1920          */
 1921         if (bp->b_flags & B_PAGING)
 1922                 panic("cannot reassign paging buffer");
 1923 
 1924         /*
 1925          * Delete from old vnode list, if on one.
 1926          */
 1927         BO_LOCK(bo);
 1928         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1929                 buf_vlist_remove(bp);
 1930         else
 1931                 panic("reassignbuf: Buffer %p not on queue.", bp);
 1932         /*
 1933          * If dirty, put on list of dirty buffers; otherwise insert onto list
 1934          * of clean buffers.
 1935          */
 1936         if (bp->b_flags & B_DELWRI) {
 1937                 if ((bo->bo_flag & BO_ONWORKLST) == 0) {
 1938                         switch (vp->v_type) {
 1939                         case VDIR:
 1940                                 delay = dirdelay;
 1941                                 break;
 1942                         case VCHR:
 1943                                 delay = metadelay;
 1944                                 break;
 1945                         default:
 1946                                 delay = filedelay;
 1947                         }
 1948                         vn_syncer_add_to_worklist(bo, delay);
 1949                 }
 1950                 buf_vlist_add(bp, bo, BX_VNDIRTY);
 1951         } else {
 1952                 buf_vlist_add(bp, bo, BX_VNCLEAN);
 1953 
 1954                 if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 1955                         mtx_lock(&sync_mtx);
 1956                         LIST_REMOVE(bo, bo_synclist);
 1957                         syncer_worklist_len--;
 1958                         mtx_unlock(&sync_mtx);
 1959                         bo->bo_flag &= ~BO_ONWORKLST;
 1960                 }
 1961         }
 1962 #ifdef INVARIANTS
 1963         bv = &bo->bo_clean;
 1964         bp = TAILQ_FIRST(&bv->bv_hd);
 1965         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1966             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1967         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 1968         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1969             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1970         bv = &bo->bo_dirty;
 1971         bp = TAILQ_FIRST(&bv->bv_hd);
 1972         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1973             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1974         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 1975         KASSERT(bp == NULL || bp->b_bufobj == bo,
 1976             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 1977 #endif
 1978         BO_UNLOCK(bo);
 1979 }
 1980 
 1981 /*
 1982  * Increment the use and hold counts on the vnode, taking care to reference
 1983  * the driver's usecount if this is a chardev.  The vholdl() will remove
 1984  * the vnode from the free list if it is presently free.  Requires the
 1985  * vnode interlock and returns with it held.
 1986  */
 1987 static void
 1988 v_incr_usecount(struct vnode *vp)
 1989 {
 1990 
 1991         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 1992         vp->v_usecount++;
 1993         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 1994                 dev_lock();
 1995                 vp->v_rdev->si_usecount++;
 1996                 dev_unlock();
 1997         }
 1998         vholdl(vp);
 1999 }
 2000 
 2001 /*
 2002  * Turn a holdcnt into a use+holdcnt such that only one call to
 2003  * v_decr_usecount is needed.
 2004  */
 2005 static void
 2006 v_upgrade_usecount(struct vnode *vp)
 2007 {
 2008 
 2009         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2010         vp->v_usecount++;
 2011         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2012                 dev_lock();
 2013                 vp->v_rdev->si_usecount++;
 2014                 dev_unlock();
 2015         }
 2016 }
 2017 
 2018 /*
 2019  * Decrement the vnode use and hold count along with the driver's usecount
 2020  * if this is a chardev.  The vdropl() below releases the vnode interlock
 2021  * as it may free the vnode.
 2022  */
 2023 static void
 2024 v_decr_usecount(struct vnode *vp)
 2025 {
 2026 
 2027         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2028         VNASSERT(vp->v_usecount > 0, vp,
 2029             ("v_decr_usecount: negative usecount"));
 2030         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2031         vp->v_usecount--;
 2032         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2033                 dev_lock();
 2034                 vp->v_rdev->si_usecount--;
 2035                 dev_unlock();
 2036         }
 2037         vdropl(vp);
 2038 }
 2039 
 2040 /*
 2041  * Decrement only the use count and driver use count.  This is intended to
 2042  * be paired with a follow on vdropl() to release the remaining hold count.
 2043  * In this way we may vgone() a vnode with a 0 usecount without risk of
 2044  * having it end up on a free list because the hold count is kept above 0.
 2045  */
 2046 static void
 2047 v_decr_useonly(struct vnode *vp)
 2048 {
 2049 
 2050         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2051         VNASSERT(vp->v_usecount > 0, vp,
 2052             ("v_decr_useonly: negative usecount"));
 2053         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2054         vp->v_usecount--;
 2055         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2056                 dev_lock();
 2057                 vp->v_rdev->si_usecount--;
 2058                 dev_unlock();
 2059         }
 2060 }
 2061 
 2062 /*
 2063  * Grab a particular vnode from the free list, increment its
 2064  * reference count and lock it.  VI_DOOMED is set if the vnode
 2065  * is being destroyed.  Only callers who specify LK_RETRY will
 2066  * see doomed vnodes.  If inactive processing was delayed in
 2067  * vput try to do it here.
 2068  */
 2069 int
 2070 vget(struct vnode *vp, int flags, struct thread *td)
 2071 {
 2072         int error;
 2073 
 2074         error = 0;
 2075         VFS_ASSERT_GIANT(vp->v_mount);
 2076         VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
 2077             ("vget: invalid lock operation"));
 2078         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 2079 
 2080         if ((flags & LK_INTERLOCK) == 0)
 2081                 VI_LOCK(vp);
 2082         vholdl(vp);
 2083         if ((error = vn_lock(vp, flags | LK_INTERLOCK)) != 0) {
 2084                 vdrop(vp);
 2085                 CTR2(KTR_VFS, "%s: impossible to lock vnode %p", __func__,
 2086                     vp);
 2087                 return (error);
 2088         }
 2089         if (vp->v_iflag & VI_DOOMED && (flags & LK_RETRY) == 0)
 2090                 panic("vget: vn_lock failed to return ENOENT\n");
 2091         VI_LOCK(vp);
 2092         /* Upgrade our holdcnt to a usecount. */
 2093         v_upgrade_usecount(vp);
 2094         /*
 2095          * We don't guarantee that any particular close will
 2096          * trigger inactive processing so just make a best effort
 2097          * here at preventing a reference to a removed file.  If
 2098          * we don't succeed no harm is done.
 2099          */
 2100         if (vp->v_iflag & VI_OWEINACT) {
 2101                 if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE && 
 2102                     (flags & LK_NOWAIT) == 0)
 2103                         vinactive(vp, td);
 2104                 vp->v_iflag &= ~VI_OWEINACT;
 2105         }
 2106         VI_UNLOCK(vp);
 2107         return (0);
 2108 }
 2109 
 2110 /*
 2111  * Increase the reference count of a vnode.
 2112  */
 2113 void
 2114 vref(struct vnode *vp)
 2115 {
 2116 
 2117         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2118         VI_LOCK(vp);
 2119         v_incr_usecount(vp);
 2120         VI_UNLOCK(vp);
 2121 }
 2122 
 2123 /*
 2124  * Return reference count of a vnode.
 2125  *
 2126  * The results of this call are only guaranteed when some mechanism other
 2127  * than the VI lock is used to stop other processes from gaining references
 2128  * to the vnode.  This may be the case if the caller holds the only reference.
 2129  * This is also useful when stale data is acceptable as race conditions may
 2130  * be accounted for by some other means.
 2131  */
 2132 int
 2133 vrefcnt(struct vnode *vp)
 2134 {
 2135         int usecnt;
 2136 
 2137         VI_LOCK(vp);
 2138         usecnt = vp->v_usecount;
 2139         VI_UNLOCK(vp);
 2140 
 2141         return (usecnt);
 2142 }
 2143 
 2144 
 2145 /*
 2146  * Vnode put/release.
 2147  * If count drops to zero, call inactive routine and return to freelist.
 2148  */
 2149 void
 2150 vrele(struct vnode *vp)
 2151 {
 2152         struct thread *td = curthread;  /* XXX */
 2153 
 2154         KASSERT(vp != NULL, ("vrele: null vp"));
 2155         VFS_ASSERT_GIANT(vp->v_mount);
 2156 
 2157         VI_LOCK(vp);
 2158 
 2159         /* Skip this v_writecount check if we're going to panic below. */
 2160         VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
 2161             ("vrele: missed vn_close"));
 2162         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2163 
 2164         if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
 2165             vp->v_usecount == 1)) {
 2166                 v_decr_usecount(vp);
 2167                 return;
 2168         }
 2169         if (vp->v_usecount != 1) {
 2170 #ifdef DIAGNOSTIC
 2171                 vprint("vrele: negative ref count", vp);
 2172 #endif
 2173                 VI_UNLOCK(vp);
 2174                 panic("vrele: negative ref cnt");
 2175         }
 2176         CTR2(KTR_VFS, "%s: return vnode %p to the freelist", __func__, vp);
 2177         /*
 2178          * We want to hold the vnode until the inactive finishes to
 2179          * prevent vgone() races.  We drop the use count here and the
 2180          * hold count below when we're done.
 2181          */
 2182         v_decr_useonly(vp);
 2183         /*
 2184          * We must call VOP_INACTIVE with the node locked. Mark
 2185          * as VI_DOINGINACT to avoid recursion.
 2186          */
 2187         vp->v_iflag |= VI_OWEINACT;
 2188         if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK) == 0) {
 2189                 VI_LOCK(vp);
 2190                 if (vp->v_usecount > 0)
 2191                         vp->v_iflag &= ~VI_OWEINACT;
 2192                 if (vp->v_iflag & VI_OWEINACT)
 2193                         vinactive(vp, td);
 2194                 VOP_UNLOCK(vp, 0);
 2195         } else {
 2196                 VI_LOCK(vp);
 2197                 if (vp->v_usecount > 0)
 2198                         vp->v_iflag &= ~VI_OWEINACT;
 2199         }
 2200         vdropl(vp);
 2201 }
 2202 
 2203 /*
 2204  * Release an already locked vnode.  This give the same effects as
 2205  * unlock+vrele(), but takes less time and avoids releasing and
 2206  * re-aquiring the lock (as vrele() acquires the lock internally.)
 2207  */
 2208 void
 2209 vput(struct vnode *vp)
 2210 {
 2211         struct thread *td = curthread;  /* XXX */
 2212         int error;
 2213 
 2214         KASSERT(vp != NULL, ("vput: null vp"));
 2215         ASSERT_VOP_LOCKED(vp, "vput");
 2216         VFS_ASSERT_GIANT(vp->v_mount);
 2217         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2218         VI_LOCK(vp);
 2219         /* Skip this v_writecount check if we're going to panic below. */
 2220         VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
 2221             ("vput: missed vn_close"));
 2222         error = 0;
 2223 
 2224         if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
 2225             vp->v_usecount == 1)) {
 2226                 VOP_UNLOCK(vp, 0);
 2227                 v_decr_usecount(vp);
 2228                 return;
 2229         }
 2230 
 2231         if (vp->v_usecount != 1) {
 2232 #ifdef DIAGNOSTIC
 2233                 vprint("vput: negative ref count", vp);
 2234 #endif
 2235                 panic("vput: negative ref cnt");
 2236         }
 2237         CTR2(KTR_VFS, "%s: return to freelist the vnode %p", __func__, vp);
 2238         /*
 2239          * We want to hold the vnode until the inactive finishes to
 2240          * prevent vgone() races.  We drop the use count here and the
 2241          * hold count below when we're done.
 2242          */
 2243         v_decr_useonly(vp);
 2244         vp->v_iflag |= VI_OWEINACT;
 2245         if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
 2246                 error = VOP_LOCK(vp, LK_UPGRADE|LK_INTERLOCK|LK_NOWAIT);
 2247                 VI_LOCK(vp);
 2248                 if (error) {
 2249                         if (vp->v_usecount > 0)
 2250                                 vp->v_iflag &= ~VI_OWEINACT;
 2251                         goto done;
 2252                 }
 2253         }
 2254         if (vp->v_usecount > 0)
 2255                 vp->v_iflag &= ~VI_OWEINACT;
 2256         if (vp->v_iflag & VI_OWEINACT)
 2257                 vinactive(vp, td);
 2258         VOP_UNLOCK(vp, 0);
 2259 done:
 2260         vdropl(vp);
 2261 }
 2262 
 2263 /*
 2264  * Somebody doesn't want the vnode recycled.
 2265  */
 2266 void
 2267 vhold(struct vnode *vp)
 2268 {
 2269 
 2270         VI_LOCK(vp);
 2271         vholdl(vp);
 2272         VI_UNLOCK(vp);
 2273 }
 2274 
 2275 void
 2276 vholdl(struct vnode *vp)
 2277 {
 2278 
 2279         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2280         vp->v_holdcnt++;
 2281         if (VSHOULDBUSY(vp))
 2282                 vbusy(vp);
 2283 }
 2284 
 2285 /*
 2286  * Note that there is one less who cares about this vnode.  vdrop() is the
 2287  * opposite of vhold().
 2288  */
 2289 void
 2290 vdrop(struct vnode *vp)
 2291 {
 2292 
 2293         VI_LOCK(vp);
 2294         vdropl(vp);
 2295 }
 2296 
 2297 /*
 2298  * Drop the hold count of the vnode.  If this is the last reference to
 2299  * the vnode we will free it if it has been vgone'd otherwise it is
 2300  * placed on the free list.
 2301  */
 2302 void
 2303 vdropl(struct vnode *vp)
 2304 {
 2305 
 2306         ASSERT_VI_LOCKED(vp, "vdropl");
 2307         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2308         if (vp->v_holdcnt <= 0)
 2309                 panic("vdrop: holdcnt %d", vp->v_holdcnt);
 2310         vp->v_holdcnt--;
 2311         if (vp->v_holdcnt == 0) {
 2312                 if (vp->v_iflag & VI_DOOMED) {
 2313                         CTR2(KTR_VFS, "%s: destroying the vnode %p", __func__,
 2314                             vp);
 2315                         vdestroy(vp);
 2316                         return;
 2317                 } else
 2318                         vfree(vp);
 2319         }
 2320         VI_UNLOCK(vp);
 2321 }
 2322 
 2323 /*
 2324  * Call VOP_INACTIVE on the vnode and manage the DOINGINACT and OWEINACT
 2325  * flags.  DOINGINACT prevents us from recursing in calls to vinactive.
 2326  * OWEINACT tracks whether a vnode missed a call to inactive due to a
 2327  * failed lock upgrade.
 2328  */
 2329 static void
 2330 vinactive(struct vnode *vp, struct thread *td)
 2331 {
 2332 
 2333         ASSERT_VOP_ELOCKED(vp, "vinactive");
 2334         ASSERT_VI_LOCKED(vp, "vinactive");
 2335         VNASSERT((vp->v_iflag & VI_DOINGINACT) == 0, vp,
 2336             ("vinactive: recursed on VI_DOINGINACT"));
 2337         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2338         vp->v_iflag |= VI_DOINGINACT;
 2339         vp->v_iflag &= ~VI_OWEINACT;
 2340         VI_UNLOCK(vp);
 2341         VOP_INACTIVE(vp, td);
 2342         VI_LOCK(vp);
 2343         VNASSERT(vp->v_iflag & VI_DOINGINACT, vp,
 2344             ("vinactive: lost VI_DOINGINACT"));
 2345         vp->v_iflag &= ~VI_DOINGINACT;
 2346 }
 2347 
 2348 /*
 2349  * Remove any vnodes in the vnode table belonging to mount point mp.
 2350  *
 2351  * If FORCECLOSE is not specified, there should not be any active ones,
 2352  * return error if any are found (nb: this is a user error, not a
 2353  * system error). If FORCECLOSE is specified, detach any active vnodes
 2354  * that are found.
 2355  *
 2356  * If WRITECLOSE is set, only flush out regular file vnodes open for
 2357  * writing.
 2358  *
 2359  * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
 2360  *
 2361  * `rootrefs' specifies the base reference count for the root vnode
 2362  * of this filesystem. The root vnode is considered busy if its
 2363  * v_usecount exceeds this value. On a successful return, vflush(, td)
 2364  * will call vrele() on the root vnode exactly rootrefs times.
 2365  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
 2366  * be zero.
 2367  */
 2368 #ifdef DIAGNOSTIC
 2369 static int busyprt = 0;         /* print out busy vnodes */
 2370 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "");
 2371 #endif
 2372 
 2373 int
 2374 vflush( struct mount *mp, int rootrefs, int flags, struct thread *td)
 2375 {
 2376         struct vnode *vp, *mvp, *rootvp = NULL;
 2377         struct vattr vattr;
 2378         int busy = 0, error;
 2379 
 2380         CTR4(KTR_VFS, "%s: mp %p with rootrefs %d and flags %d", __func__, mp,
 2381             rootrefs, flags);
 2382         if (rootrefs > 0) {
 2383                 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
 2384                     ("vflush: bad args"));
 2385                 /*
 2386                  * Get the filesystem root vnode. We can vput() it
 2387                  * immediately, since with rootrefs > 0, it won't go away.
 2388                  */
 2389                 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rootvp)) != 0) {
 2390                         CTR2(KTR_VFS, "%s: vfs_root lookup failed with %d",
 2391                             __func__, error);
 2392                         return (error);
 2393                 }
 2394                 vput(rootvp);
 2395 
 2396         }
 2397         MNT_ILOCK(mp);
 2398 loop:
 2399         MNT_VNODE_FOREACH(vp, mp, mvp) {
 2400 
 2401                 VI_LOCK(vp);
 2402                 vholdl(vp);
 2403                 MNT_IUNLOCK(mp);
 2404                 error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE);
 2405                 if (error) {
 2406                         vdrop(vp);
 2407                         MNT_ILOCK(mp);
 2408                         MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);
 2409                         goto loop;
 2410                 }
 2411                 /*
 2412                  * Skip over a vnodes marked VV_SYSTEM.
 2413                  */
 2414                 if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
 2415                         VOP_UNLOCK(vp, 0);
 2416                         vdrop(vp);
 2417                         MNT_ILOCK(mp);
 2418                         continue;
 2419                 }
 2420                 /*
 2421                  * If WRITECLOSE is set, flush out unlinked but still open
 2422                  * files (even if open only for reading) and regular file
 2423                  * vnodes open for writing.
 2424                  */
 2425                 if (flags & WRITECLOSE) {
 2426                         error = VOP_GETATTR(vp, &vattr, td->td_ucred);
 2427                         VI_LOCK(vp);
 2428 
 2429                         if ((vp->v_type == VNON ||
 2430                             (error == 0 && vattr.va_nlink > 0)) &&
 2431                             (vp->v_writecount == 0 || vp->v_type != VREG)) {
 2432                                 VOP_UNLOCK(vp, 0);
 2433                                 vdropl(vp);
 2434                                 MNT_ILOCK(mp);
 2435                                 continue;
 2436                         }
 2437                 } else
 2438                         VI_LOCK(vp);
 2439                 /*
 2440                  * With v_usecount == 0, all we need to do is clear out the
 2441                  * vnode data structures and we are done.
 2442                  *
 2443                  * If FORCECLOSE is set, forcibly close the vnode.
 2444                  */
 2445                 if (vp->v_usecount == 0 || (flags & FORCECLOSE)) {
 2446                         VNASSERT(vp->v_usecount == 0 ||
 2447                             (vp->v_type != VCHR && vp->v_type != VBLK), vp,
 2448                             ("device VNODE %p is FORCECLOSED", vp));
 2449                         vgonel(vp);
 2450                 } else {
 2451                         busy++;
 2452 #ifdef DIAGNOSTIC
 2453                         if (busyprt)
 2454                                 vprint("vflush: busy vnode", vp);
 2455 #endif
 2456                 }
 2457                 VOP_UNLOCK(vp, 0);
 2458                 vdropl(vp);
 2459                 MNT_ILOCK(mp);
 2460         }
 2461         MNT_IUNLOCK(mp);
 2462         if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
 2463                 /*
 2464                  * If just the root vnode is busy, and if its refcount
 2465                  * is equal to `rootrefs', then go ahead and kill it.
 2466                  */
 2467                 VI_LOCK(rootvp);
 2468                 KASSERT(busy > 0, ("vflush: not busy"));
 2469                 VNASSERT(rootvp->v_usecount >= rootrefs, rootvp,
 2470                     ("vflush: usecount %d < rootrefs %d",
 2471                      rootvp->v_usecount, rootrefs));
 2472                 if (busy == 1 && rootvp->v_usecount == rootrefs) {
 2473                         VOP_LOCK(rootvp, LK_EXCLUSIVE|LK_INTERLOCK);
 2474                         vgone(rootvp);
 2475                         VOP_UNLOCK(rootvp, 0);
 2476                         busy = 0;
 2477                 } else
 2478                         VI_UNLOCK(rootvp);
 2479         }
 2480         if (busy) {
 2481                 CTR2(KTR_VFS, "%s: failing as %d vnodes are busy", __func__,
 2482                     busy);
 2483                 return (EBUSY);
 2484         }
 2485         for (; rootrefs > 0; rootrefs--)
 2486                 vrele(rootvp);
 2487         return (0);
 2488 }
 2489 
 2490 /*
 2491  * Recycle an unused vnode to the front of the free list.
 2492  */
 2493 int
 2494 vrecycle(struct vnode *vp, struct thread *td)
 2495 {
 2496         int recycled;
 2497 
 2498         ASSERT_VOP_ELOCKED(vp, "vrecycle");
 2499         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2500         recycled = 0;
 2501         VI_LOCK(vp);
 2502         if (vp->v_usecount == 0) {
 2503                 recycled = 1;
 2504                 vgonel(vp);
 2505         }
 2506         VI_UNLOCK(vp);
 2507         return (recycled);
 2508 }
 2509 
 2510 /*
 2511  * Eliminate all activity associated with a vnode
 2512  * in preparation for reuse.
 2513  */
 2514 void
 2515 vgone(struct vnode *vp)
 2516 {
 2517         VI_LOCK(vp);
 2518         vgonel(vp);
 2519         VI_UNLOCK(vp);
 2520 }
 2521 
 2522 /*
 2523  * vgone, with the vp interlock held.
 2524  */
 2525 void
 2526 vgonel(struct vnode *vp)
 2527 {
 2528         struct thread *td;
 2529         int oweinact;
 2530         int active;
 2531         struct mount *mp;
 2532 
 2533         ASSERT_VOP_ELOCKED(vp, "vgonel");
 2534         ASSERT_VI_LOCKED(vp, "vgonel");
 2535         VNASSERT(vp->v_holdcnt, vp,
 2536             ("vgonel: vp %p has no reference.", vp));
 2537         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2538         td = curthread;
 2539 
 2540         /*
 2541          * Don't vgonel if we're already doomed.
 2542          */
 2543         if (vp->v_iflag & VI_DOOMED)
 2544                 return;
 2545         vp->v_iflag |= VI_DOOMED;
 2546         /*
 2547          * Check to see if the vnode is in use.  If so, we have to call
 2548          * VOP_CLOSE() and VOP_INACTIVE().
 2549          */
 2550         active = vp->v_usecount;
 2551         oweinact = (vp->v_iflag & VI_OWEINACT);
 2552         VI_UNLOCK(vp);
 2553         /*
 2554          * Clean out any buffers associated with the vnode.
 2555          * If the flush fails, just toss the buffers.
 2556          */
 2557         mp = NULL;
 2558         if (!TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd))
 2559                 (void) vn_start_secondary_write(vp, &mp, V_WAIT);
 2560         if (vinvalbuf(vp, V_SAVE, 0, 0) != 0)
 2561                 vinvalbuf(vp, 0, 0, 0);
 2562 
 2563         /*
 2564          * If purging an active vnode, it must be closed and
 2565          * deactivated before being reclaimed.
 2566          */
 2567         if (active)
 2568                 VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
 2569         if (oweinact || active) {
 2570                 VI_LOCK(vp);
 2571                 if ((vp->v_iflag & VI_DOINGINACT) == 0)
 2572                         vinactive(vp, td);
 2573                 VI_UNLOCK(vp);
 2574         }
 2575         /*
 2576          * Reclaim the vnode.
 2577          */
 2578         if (VOP_RECLAIM(vp, td))
 2579                 panic("vgone: cannot reclaim");
 2580         if (mp != NULL)
 2581                 vn_finished_secondary_write(mp);
 2582         VNASSERT(vp->v_object == NULL, vp,
 2583             ("vop_reclaim left v_object vp=%p, tag=%s", vp, vp->v_tag));
 2584         /*
 2585          * Clear the advisory locks and wake up waiting threads.
 2586          */
 2587         lf_purgelocks(vp, &(vp->v_lockf));
 2588         /*
 2589          * Delete from old mount point vnode list.
 2590          */
 2591         delmntque(vp);
 2592         cache_purge(vp);
 2593         /*
 2594          * Done with purge, reset to the standard lock and invalidate
 2595          * the vnode.
 2596          */
 2597         VI_LOCK(vp);
 2598         vp->v_vnlock = &vp->v_lock;
 2599         vp->v_op = &dead_vnodeops;
 2600         vp->v_tag = "none";
 2601         vp->v_type = VBAD;
 2602 }
 2603 
 2604 /*
 2605  * Calculate the total number of references to a special device.
 2606  */
 2607 int
 2608 vcount(struct vnode *vp)
 2609 {
 2610         int count;
 2611 
 2612         dev_lock();
 2613         count = vp->v_rdev->si_usecount;
 2614         dev_unlock();
 2615         return (count);
 2616 }
 2617 
 2618 /*
 2619  * Same as above, but using the struct cdev *as argument
 2620  */
 2621 int
 2622 count_dev(struct cdev *dev)
 2623 {
 2624         int count;
 2625 
 2626         dev_lock();
 2627         count = dev->si_usecount;
 2628         dev_unlock();
 2629         return(count);
 2630 }
 2631 
 2632 /*
 2633  * Print out a description of a vnode.
 2634  */
 2635 static char *typename[] =
 2636 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD",
 2637  "VMARKER"};
 2638 
 2639 void
 2640 vn_printf(struct vnode *vp, const char *fmt, ...)
 2641 {
 2642         va_list ap;
 2643         char buf[256], buf2[16];
 2644         u_long flags;
 2645 
 2646         va_start(ap, fmt);
 2647         vprintf(fmt, ap);
 2648         va_end(ap);
 2649         printf("%p: ", (void *)vp);
 2650         printf("tag %s, type %s\n", vp->v_tag, typename[vp->v_type]);
 2651         printf("    usecount %d, writecount %d, refcount %d mountedhere %p\n",
 2652             vp->v_usecount, vp->v_writecount, vp->v_holdcnt, vp->v_mountedhere);
 2653         buf[0] = '\0';
 2654         buf[1] = '\0';
 2655         if (vp->v_vflag & VV_ROOT)
 2656                 strlcat(buf, "|VV_ROOT", sizeof(buf));
 2657         if (vp->v_vflag & VV_ISTTY)
 2658                 strlcat(buf, "|VV_ISTTY", sizeof(buf));
 2659         if (vp->v_vflag & VV_NOSYNC)
 2660                 strlcat(buf, "|VV_NOSYNC", sizeof(buf));
 2661         if (vp->v_vflag & VV_CACHEDLABEL)
 2662                 strlcat(buf, "|VV_CACHEDLABEL", sizeof(buf));
 2663         if (vp->v_vflag & VV_TEXT)
 2664                 strlcat(buf, "|VV_TEXT", sizeof(buf));
 2665         if (vp->v_vflag & VV_COPYONWRITE)
 2666                 strlcat(buf, "|VV_COPYONWRITE", sizeof(buf));
 2667         if (vp->v_vflag & VV_SYSTEM)
 2668                 strlcat(buf, "|VV_SYSTEM", sizeof(buf));
 2669         if (vp->v_vflag & VV_PROCDEP)
 2670                 strlcat(buf, "|VV_PROCDEP", sizeof(buf));
 2671         if (vp->v_vflag & VV_NOKNOTE)
 2672                 strlcat(buf, "|VV_NOKNOTE", sizeof(buf));
 2673         if (vp->v_vflag & VV_DELETED)
 2674                 strlcat(buf, "|VV_DELETED", sizeof(buf));
 2675         if (vp->v_vflag & VV_MD)
 2676                 strlcat(buf, "|VV_MD", sizeof(buf));
 2677         flags = vp->v_vflag & ~(VV_ROOT | VV_ISTTY | VV_NOSYNC |
 2678             VV_CACHEDLABEL | VV_TEXT | VV_COPYONWRITE | VV_SYSTEM | VV_PROCDEP |
 2679             VV_NOKNOTE | VV_DELETED | VV_MD);
 2680         if (flags != 0) {
 2681                 snprintf(buf2, sizeof(buf2), "|VV(0x%lx)", flags);
 2682                 strlcat(buf, buf2, sizeof(buf));
 2683         }
 2684         if (vp->v_iflag & VI_MOUNT)
 2685                 strlcat(buf, "|VI_MOUNT", sizeof(buf));
 2686         if (vp->v_iflag & VI_AGE)
 2687                 strlcat(buf, "|VI_AGE", sizeof(buf));
 2688         if (vp->v_iflag & VI_DOOMED)
 2689                 strlcat(buf, "|VI_DOOMED", sizeof(buf));
 2690         if (vp->v_iflag & VI_FREE)
 2691                 strlcat(buf, "|VI_FREE", sizeof(buf));
 2692         if (vp->v_iflag & VI_OBJDIRTY)
 2693                 strlcat(buf, "|VI_OBJDIRTY", sizeof(buf));
 2694         if (vp->v_iflag & VI_DOINGINACT)
 2695                 strlcat(buf, "|VI_DOINGINACT", sizeof(buf));
 2696         if (vp->v_iflag & VI_OWEINACT)
 2697                 strlcat(buf, "|VI_OWEINACT", sizeof(buf));
 2698         flags = vp->v_iflag & ~(VI_MOUNT | VI_AGE | VI_DOOMED | VI_FREE |
 2699             VI_OBJDIRTY | VI_DOINGINACT | VI_OWEINACT);
 2700         if (flags != 0) {
 2701                 snprintf(buf2, sizeof(buf2), "|VI(0x%lx)", flags);
 2702                 strlcat(buf, buf2, sizeof(buf));
 2703         }
 2704         printf("    flags (%s)\n", buf + 1);
 2705         if (mtx_owned(VI_MTX(vp)))
 2706                 printf(" VI_LOCKed");
 2707         if (vp->v_object != NULL)
 2708                 printf("    v_object %p ref %d pages %d\n",
 2709                     vp->v_object, vp->v_object->ref_count,
 2710                     vp->v_object->resident_page_count);
 2711         printf("    ");
 2712         lockmgr_printinfo(vp->v_vnlock);
 2713         if (vp->v_data != NULL)
 2714                 VOP_PRINT(vp);
 2715 }
 2716 
 2717 #ifdef DDB
 2718 /*
 2719  * List all of the locked vnodes in the system.
 2720  * Called when debugging the kernel.
 2721  */
 2722 DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
 2723 {
 2724         struct mount *mp, *nmp;
 2725         struct vnode *vp;
 2726 
 2727         /*
 2728          * Note: because this is DDB, we can't obey the locking semantics
 2729          * for these structures, which means we could catch an inconsistent
 2730          * state and dereference a nasty pointer.  Not much to be done
 2731          * about that.
 2732          */
 2733         db_printf("Locked vnodes\n");
 2734         for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
 2735                 nmp = TAILQ_NEXT(mp, mnt_list);
 2736                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2737                         if (vp->v_type != VMARKER &&
 2738                             VOP_ISLOCKED(vp))
 2739                                 vprint("", vp);
 2740                 }
 2741                 nmp = TAILQ_NEXT(mp, mnt_list);
 2742         }
 2743 }
 2744 
 2745 /*
 2746  * Show details about the given vnode.
 2747  */
 2748 DB_SHOW_COMMAND(vnode, db_show_vnode)
 2749 {
 2750         struct vnode *vp;
 2751 
 2752         if (!have_addr)
 2753                 return;
 2754         vp = (struct vnode *)addr;
 2755         vn_printf(vp, "vnode ");
 2756 }
 2757 
 2758 /*
 2759  * Show details about the given mount point.
 2760  */
 2761 DB_SHOW_COMMAND(mount, db_show_mount)
 2762 {
 2763         struct mount *mp;
 2764         struct statfs *sp;
 2765         struct vnode *vp;
 2766         char buf[512];
 2767         u_int flags;
 2768 
 2769         if (!have_addr) {
 2770                 /* No address given, print short info about all mount points. */
 2771                 TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 2772                         db_printf("%p %s on %s (%s)\n", mp,
 2773                             mp->mnt_stat.f_mntfromname,
 2774                             mp->mnt_stat.f_mntonname,
 2775                             mp->mnt_stat.f_fstypename);
 2776                         if (db_pager_quit)
 2777                                 break;
 2778                 }
 2779                 db_printf("\nMore info: show mount <addr>\n");
 2780                 return;
 2781         }
 2782 
 2783         mp = (struct mount *)addr;
 2784         db_printf("%p %s on %s (%s)\n", mp, mp->mnt_stat.f_mntfromname,
 2785             mp->mnt_stat.f_mntonname, mp->mnt_stat.f_fstypename);
 2786 
 2787         buf[0] = '\0';
 2788         flags = mp->mnt_flag;
 2789 #define MNT_FLAG(flag)  do {                                            \
 2790         if (flags & (flag)) {                                           \
 2791                 if (buf[0] != '\0')                                     \
 2792                         strlcat(buf, ", ", sizeof(buf));                \
 2793                 strlcat(buf, (#flag) + 4, sizeof(buf));                 \
 2794                 flags &= ~(flag);                                       \
 2795         }                                                               \
 2796 } while (0)
 2797         MNT_FLAG(MNT_RDONLY);
 2798         MNT_FLAG(MNT_SYNCHRONOUS);
 2799         MNT_FLAG(MNT_NOEXEC);
 2800         MNT_FLAG(MNT_NOSUID);
 2801         MNT_FLAG(MNT_UNION);
 2802         MNT_FLAG(MNT_ASYNC);
 2803         MNT_FLAG(MNT_SUIDDIR);
 2804         MNT_FLAG(MNT_SOFTDEP);
 2805         MNT_FLAG(MNT_NOSYMFOLLOW);
 2806         MNT_FLAG(MNT_GJOURNAL);
 2807         MNT_FLAG(MNT_MULTILABEL);
 2808         MNT_FLAG(MNT_ACLS);
 2809         MNT_FLAG(MNT_NOATIME);
 2810         MNT_FLAG(MNT_NOCLUSTERR);
 2811         MNT_FLAG(MNT_NOCLUSTERW);
 2812         MNT_FLAG(MNT_EXRDONLY);
 2813         MNT_FLAG(MNT_EXPORTED);
 2814         MNT_FLAG(MNT_DEFEXPORTED);
 2815         MNT_FLAG(MNT_EXPORTANON);
 2816         MNT_FLAG(MNT_EXKERB);
 2817         MNT_FLAG(MNT_EXPUBLIC);
 2818         MNT_FLAG(MNT_LOCAL);
 2819         MNT_FLAG(MNT_QUOTA);
 2820         MNT_FLAG(MNT_ROOTFS);
 2821         MNT_FLAG(MNT_USER);
 2822         MNT_FLAG(MNT_IGNORE);
 2823         MNT_FLAG(MNT_UPDATE);
 2824         MNT_FLAG(MNT_DELEXPORT);
 2825         MNT_FLAG(MNT_RELOAD);
 2826         MNT_FLAG(MNT_FORCE);
 2827         MNT_FLAG(MNT_SNAPSHOT);
 2828         MNT_FLAG(MNT_BYFSID);
 2829 #undef MNT_FLAG
 2830         if (flags != 0) {
 2831                 if (buf[0] != '\0')
 2832                         strlcat(buf, ", ", sizeof(buf));
 2833                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 2834                     "0x%08x", flags);
 2835         }
 2836         db_printf("    mnt_flag = %s\n", buf);
 2837 
 2838         buf[0] = '\0';
 2839         flags = mp->mnt_kern_flag;
 2840 #define MNT_KERN_FLAG(flag)     do {                                    \
 2841         if (flags & (flag)) {                                           \
 2842                 if (buf[0] != '\0')                                     \
 2843                         strlcat(buf, ", ", sizeof(buf));                \
 2844                 strlcat(buf, (#flag) + 5, sizeof(buf));                 \
 2845                 flags &= ~(flag);                                       \
 2846         }                                                               \
 2847 } while (0)
 2848         MNT_KERN_FLAG(MNTK_UNMOUNTF);
 2849         MNT_KERN_FLAG(MNTK_ASYNC);
 2850         MNT_KERN_FLAG(MNTK_SOFTDEP);
 2851         MNT_KERN_FLAG(MNTK_NOINSMNTQ);
 2852         MNT_KERN_FLAG(MNTK_UNMOUNT);
 2853         MNT_KERN_FLAG(MNTK_MWAIT);
 2854         MNT_KERN_FLAG(MNTK_SUSPEND);
 2855         MNT_KERN_FLAG(MNTK_SUSPEND2);
 2856         MNT_KERN_FLAG(MNTK_SUSPENDED);
 2857         MNT_KERN_FLAG(MNTK_MPSAFE);
 2858         MNT_KERN_FLAG(MNTK_NOKNOTE);
 2859         MNT_KERN_FLAG(MNTK_LOOKUP_SHARED);
 2860 #undef MNT_KERN_FLAG
 2861         if (flags != 0) {
 2862                 if (buf[0] != '\0')
 2863                         strlcat(buf, ", ", sizeof(buf));
 2864                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 2865                     "0x%08x", flags);
 2866         }
 2867         db_printf("    mnt_kern_flag = %s\n", buf);
 2868 
 2869         sp = &mp->mnt_stat;
 2870         db_printf("    mnt_stat = { version=%u type=%u flags=0x%016jx "
 2871             "bsize=%ju iosize=%ju blocks=%ju bfree=%ju bavail=%jd files=%ju "
 2872             "ffree=%jd syncwrites=%ju asyncwrites=%ju syncreads=%ju "
 2873             "asyncreads=%ju namemax=%u owner=%u fsid=[%d, %d] }\n",
 2874             (u_int)sp->f_version, (u_int)sp->f_type, (uintmax_t)sp->f_flags,
 2875             (uintmax_t)sp->f_bsize, (uintmax_t)sp->f_iosize,
 2876             (uintmax_t)sp->f_blocks, (uintmax_t)sp->f_bfree,
 2877             (intmax_t)sp->f_bavail, (uintmax_t)sp->f_files,
 2878             (intmax_t)sp->f_ffree, (uintmax_t)sp->f_syncwrites,
 2879             (uintmax_t)sp->f_asyncwrites, (uintmax_t)sp->f_syncreads,
 2880             (uintmax_t)sp->f_asyncreads, (u_int)sp->f_namemax,
 2881             (u_int)sp->f_owner, (int)sp->f_fsid.val[0], (int)sp->f_fsid.val[1]);
 2882 
 2883         db_printf("    mnt_cred = { uid=%u ruid=%u",
 2884             (u_int)mp->mnt_cred->cr_uid, (u_int)mp->mnt_cred->cr_ruid);
 2885         if (jailed(mp->mnt_cred))
 2886                 db_printf(", jail=%d", mp->mnt_cred->cr_prison->pr_id);
 2887         db_printf(" }\n");
 2888         db_printf("    mnt_ref = %d\n", mp->mnt_ref);
 2889         db_printf("    mnt_gen = %d\n", mp->mnt_gen);
 2890         db_printf("    mnt_nvnodelistsize = %d\n", mp->mnt_nvnodelistsize);
 2891         db_printf("    mnt_writeopcount = %d\n", mp->mnt_writeopcount);
 2892         db_printf("    mnt_noasync = %u\n", mp->mnt_noasync);
 2893         db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
 2894         db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
 2895         db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
 2896         db_printf("    mnt_secondary_writes = %d\n", mp->mnt_secondary_writes);
 2897         db_printf("    mnt_secondary_accwrites = %d\n",
 2898             mp->mnt_secondary_accwrites);
 2899         db_printf("    mnt_gjprovider = %s\n",
 2900             mp->mnt_gjprovider != NULL ? mp->mnt_gjprovider : "NULL");
 2901         db_printf("\n");
 2902 
 2903         TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2904                 if (vp->v_type != VMARKER) {
 2905                         vn_printf(vp, "vnode ");
 2906                         if (db_pager_quit)
 2907                                 break;
 2908                 }
 2909         }
 2910 }
 2911 #endif  /* DDB */
 2912 
 2913 /*
 2914  * Fill in a struct xvfsconf based on a struct vfsconf.
 2915  */
 2916 static void
 2917 vfsconf2x(struct vfsconf *vfsp, struct xvfsconf *xvfsp)
 2918 {
 2919 
 2920         strcpy(xvfsp->vfc_name, vfsp->vfc_name);
 2921         xvfsp->vfc_typenum = vfsp->vfc_typenum;
 2922         xvfsp->vfc_refcount = vfsp->vfc_refcount;
 2923         xvfsp->vfc_flags = vfsp->vfc_flags;
 2924         /*
 2925          * These are unused in userland, we keep them
 2926          * to not break binary compatibility.
 2927          */
 2928         xvfsp->vfc_vfsops = NULL;
 2929         xvfsp->vfc_next = NULL;
 2930 }
 2931 
 2932 /*
 2933  * Top level filesystem related information gathering.
 2934  */
 2935 static int
 2936 sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
 2937 {
 2938         struct vfsconf *vfsp;
 2939         struct xvfsconf xvfsp;
 2940         int error;
 2941 
 2942         error = 0;
 2943         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 2944                 bzero(&xvfsp, sizeof(xvfsp));
 2945                 vfsconf2x(vfsp, &xvfsp);
 2946                 error = SYSCTL_OUT(req, &xvfsp, sizeof xvfsp);
 2947                 if (error)
 2948                         break;
 2949         }
 2950         return (error);
 2951 }
 2952 
 2953 SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
 2954     "S,xvfsconf", "List of all configured filesystems");
 2955 
 2956 #ifndef BURN_BRIDGES
 2957 static int      sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
 2958 
 2959 static int
 2960 vfs_sysctl(SYSCTL_HANDLER_ARGS)
 2961 {
 2962         int *name = (int *)arg1 - 1;    /* XXX */
 2963         u_int namelen = arg2 + 1;       /* XXX */
 2964         struct vfsconf *vfsp;
 2965         struct xvfsconf xvfsp;
 2966 
 2967         printf("WARNING: userland calling deprecated sysctl, "
 2968             "please rebuild world\n");
 2969 
 2970 #if 1 || defined(COMPAT_PRELITE2)
 2971         /* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
 2972         if (namelen == 1)
 2973                 return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
 2974 #endif
 2975 
 2976         switch (name[1]) {
 2977         case VFS_MAXTYPENUM:
 2978                 if (namelen != 2)
 2979                         return (ENOTDIR);
 2980                 return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
 2981         case VFS_CONF:
 2982                 if (namelen != 3)
 2983                         return (ENOTDIR);       /* overloaded */
 2984                 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
 2985                         if (vfsp->vfc_typenum == name[2])
 2986                                 break;
 2987                 if (vfsp == NULL)
 2988                         return (EOPNOTSUPP);
 2989                 bzero(&xvfsp, sizeof(xvfsp));
 2990                 vfsconf2x(vfsp, &xvfsp);
 2991                 return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 2992         }
 2993         return (EOPNOTSUPP);
 2994 }
 2995 
 2996 static SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP,
 2997         vfs_sysctl, "Generic filesystem");
 2998 
 2999 #if 1 || defined(COMPAT_PRELITE2)
 3000 
 3001 static int
 3002 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
 3003 {
 3004         int error;
 3005         struct vfsconf *vfsp;
 3006         struct ovfsconf ovfs;
 3007 
 3008         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3009                 bzero(&ovfs, sizeof(ovfs));
 3010                 ovfs.vfc_vfsops = vfsp->vfc_vfsops;     /* XXX used as flag */
 3011                 strcpy(ovfs.vfc_name, vfsp->vfc_name);
 3012                 ovfs.vfc_index = vfsp->vfc_typenum;
 3013                 ovfs.vfc_refcount = vfsp->vfc_refcount;
 3014                 ovfs.vfc_flags = vfsp->vfc_flags;
 3015                 error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
 3016                 if (error)
 3017                         return error;
 3018         }
 3019         return 0;
 3020 }
 3021 
 3022 #endif /* 1 || COMPAT_PRELITE2 */
 3023 #endif /* !BURN_BRIDGES */
 3024 
 3025 #define KINFO_VNODESLOP         10
 3026 #ifdef notyet
 3027 /*
 3028  * Dump vnode list (via sysctl).
 3029  */
 3030 /* ARGSUSED */
 3031 static int
 3032 sysctl_vnode(SYSCTL_HANDLER_ARGS)
 3033 {
 3034         struct xvnode *xvn;
 3035         struct mount *mp;
 3036         struct vnode *vp;
 3037         int error, len, n;
 3038 
 3039         /*
 3040          * Stale numvnodes access is not fatal here.
 3041          */
 3042         req->lock = 0;
 3043         len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
 3044         if (!req->oldptr)
 3045                 /* Make an estimate */
 3046                 return (SYSCTL_OUT(req, 0, len));
 3047 
 3048         error = sysctl_wire_old_buffer(req, 0);
 3049         if (error != 0)
 3050                 return (error);
 3051         xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
 3052         n = 0;
 3053         mtx_lock(&mountlist_mtx);
 3054         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 3055                 if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
 3056                         continue;
 3057                 MNT_ILOCK(mp);
 3058                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3059                         if (n == len)
 3060                                 break;
 3061                         vref(vp);
 3062                         xvn[n].xv_size = sizeof *xvn;
 3063                         xvn[n].xv_vnode = vp;
 3064                         xvn[n].xv_id = 0;       /* XXX compat */
 3065 #define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
 3066                         XV_COPY(usecount);
 3067                         XV_COPY(writecount);
 3068                         XV_COPY(holdcnt);
 3069                         XV_COPY(mount);
 3070                         XV_COPY(numoutput);
 3071                         XV_COPY(type);
 3072 #undef XV_COPY
 3073                         xvn[n].xv_flag = vp->v_vflag;
 3074 
 3075                         switch (vp->v_type) {
 3076                         case VREG:
 3077                         case VDIR:
 3078                         case VLNK:
 3079                                 break;
 3080                         case VBLK:
 3081                         case VCHR:
 3082                                 if (vp->v_rdev == NULL) {
 3083                                         vrele(vp);
 3084                                         continue;
 3085                                 }
 3086                                 xvn[n].xv_dev = dev2udev(vp->v_rdev);
 3087                                 break;
 3088                         case VSOCK:
 3089                                 xvn[n].xv_socket = vp->v_socket;
 3090                                 break;
 3091                         case VFIFO:
 3092                                 xvn[n].xv_fifo = vp->v_fifoinfo;
 3093                                 break;
 3094                         case VNON:
 3095                         case VBAD:
 3096                         default:
 3097                                 /* shouldn't happen? */
 3098                                 vrele(vp);
 3099                                 continue;
 3100                         }
 3101                         vrele(vp);
 3102                         ++n;
 3103                 }
 3104                 MNT_IUNLOCK(mp);
 3105                 mtx_lock(&mountlist_mtx);
 3106                 vfs_unbusy(mp);
 3107                 if (n == len)
 3108                         break;
 3109         }
 3110         mtx_unlock(&mountlist_mtx);
 3111 
 3112         error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
 3113         free(xvn, M_TEMP);
 3114         return (error);
 3115 }
 3116 
 3117 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
 3118         0, 0, sysctl_vnode, "S,xvnode", "");
 3119 #endif
 3120 
 3121 /*
 3122  * Unmount all filesystems. The list is traversed in reverse order
 3123  * of mounting to avoid dependencies.
 3124  */
 3125 void
 3126 vfs_unmountall(void)
 3127 {
 3128         struct mount *mp;
 3129         struct thread *td;
 3130         int error;
 3131 
 3132         KASSERT(curthread != NULL, ("vfs_unmountall: NULL curthread"));
 3133         CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__);
 3134         td = curthread;
 3135 
 3136         /*
 3137          * Since this only runs when rebooting, it is not interlocked.
 3138          */
 3139         while(!TAILQ_EMPTY(&mountlist)) {
 3140                 mp = TAILQ_LAST(&mountlist, mntlist);
 3141                 error = dounmount(mp, MNT_FORCE, td);
 3142                 if (error) {
 3143                         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 3144                         /*
 3145                          * XXX: Due to the way in which we mount the root
 3146                          * file system off of devfs, devfs will generate a
 3147                          * "busy" warning when we try to unmount it before
 3148                          * the root.  Don't print a warning as a result in
 3149                          * order to avoid false positive errors that may
 3150                          * cause needless upset.
 3151                          */
 3152                         if (strcmp(mp->mnt_vfc->vfc_name, "devfs") != 0) {
 3153                                 printf("unmount of %s failed (",
 3154                                     mp->mnt_stat.f_mntonname);
 3155                                 if (error == EBUSY)
 3156                                         printf("BUSY)\n");
 3157                                 else
 3158                                         printf("%d)\n", error);
 3159                         }
 3160                 } else {
 3161                         /* The unmount has removed mp from the mountlist */
 3162                 }
 3163         }
 3164 }
 3165 
 3166 /*
 3167  * perform msync on all vnodes under a mount point
 3168  * the mount point must be locked.
 3169  */
 3170 void
 3171 vfs_msync(struct mount *mp, int flags)
 3172 {
 3173         struct vnode *vp, *mvp;
 3174         struct vm_object *obj;
 3175 
 3176         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
 3177         MNT_ILOCK(mp);
 3178         MNT_VNODE_FOREACH(vp, mp, mvp) {
 3179                 VI_LOCK(vp);
 3180                 if ((vp->v_iflag & VI_OBJDIRTY) &&
 3181                     (flags == MNT_WAIT || VOP_ISLOCKED(vp) == 0)) {
 3182                         MNT_IUNLOCK(mp);
 3183                         if (!vget(vp,
 3184                             LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
 3185                             curthread)) {
 3186                                 if (vp->v_vflag & VV_NOSYNC) {  /* unlinked */
 3187                                         vput(vp);
 3188                                         MNT_ILOCK(mp);
 3189                                         continue;
 3190                                 }
 3191 
 3192                                 obj = vp->v_object;
 3193                                 if (obj != NULL) {
 3194                                         VM_OBJECT_LOCK(obj);
 3195                                         vm_object_page_clean(obj, 0, 0,
 3196                                             flags == MNT_WAIT ?
 3197                                             OBJPC_SYNC : OBJPC_NOSYNC);
 3198                                         VM_OBJECT_UNLOCK(obj);
 3199                                 }
 3200                                 vput(vp);
 3201                         }
 3202                         MNT_ILOCK(mp);
 3203                 } else
 3204                         VI_UNLOCK(vp);
 3205         }
 3206         MNT_IUNLOCK(mp);
 3207 }
 3208 
 3209 /*
 3210  * Mark a vnode as free, putting it up for recycling.
 3211  */
 3212 static void
 3213 vfree(struct vnode *vp)
 3214 {
 3215 
 3216         ASSERT_VI_LOCKED(vp, "vfree");
 3217         mtx_lock(&vnode_free_list_mtx);
 3218         VNASSERT(vp->v_op != NULL, vp, ("vfree: vnode already reclaimed."));
 3219         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp, ("vnode already free"));
 3220         VNASSERT(VSHOULDFREE(vp), vp, ("vfree: freeing when we shouldn't"));
 3221         VNASSERT((vp->v_iflag & VI_DOOMED) == 0, vp,
 3222             ("vfree: Freeing doomed vnode"));
 3223         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3224         if (vp->v_iflag & VI_AGE) {
 3225                 TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
 3226         } else {
 3227                 TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 3228         }
 3229         freevnodes++;
 3230         vp->v_iflag &= ~VI_AGE;
 3231         vp->v_iflag |= VI_FREE;
 3232         mtx_unlock(&vnode_free_list_mtx);
 3233 }
 3234 
 3235 /*
 3236  * Opposite of vfree() - mark a vnode as in use.
 3237  */
 3238 static void
 3239 vbusy(struct vnode *vp)
 3240 {
 3241         ASSERT_VI_LOCKED(vp, "vbusy");
 3242         VNASSERT((vp->v_iflag & VI_FREE) != 0, vp, ("vnode not free"));
 3243         VNASSERT(vp->v_op != NULL, vp, ("vbusy: vnode already reclaimed."));
 3244         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3245 
 3246         mtx_lock(&vnode_free_list_mtx);
 3247         TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
 3248         freevnodes--;
 3249         vp->v_iflag &= ~(VI_FREE|VI_AGE);
 3250         mtx_unlock(&vnode_free_list_mtx);
 3251 }
 3252 
 3253 static void
 3254 destroy_vpollinfo(struct vpollinfo *vi)
 3255 {
 3256         knlist_destroy(&vi->vpi_selinfo.si_note);
 3257         mtx_destroy(&vi->vpi_lock);
 3258         uma_zfree(vnodepoll_zone, vi);
 3259 }
 3260 
 3261 /*
 3262  * Initalize per-vnode helper structure to hold poll-related state.
 3263  */
 3264 void
 3265 v_addpollinfo(struct vnode *vp)
 3266 {
 3267         struct vpollinfo *vi;
 3268 
 3269         if (vp->v_pollinfo != NULL)
 3270                 return;
 3271         vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
 3272         mtx_init(&vi->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
 3273         knlist_init(&vi->vpi_selinfo.si_note, vp, vfs_knllock,
 3274             vfs_knlunlock, vfs_knl_assert_locked, vfs_knl_assert_unlocked);
 3275         VI_LOCK(vp);
 3276         if (vp->v_pollinfo != NULL) {
 3277                 VI_UNLOCK(vp);
 3278                 destroy_vpollinfo(vi);
 3279                 return;
 3280         }
 3281         vp->v_pollinfo = vi;
 3282         VI_UNLOCK(vp);
 3283 }
 3284 
 3285 /*
 3286  * Record a process's interest in events which might happen to
 3287  * a vnode.  Because poll uses the historic select-style interface
 3288  * internally, this routine serves as both the ``check for any
 3289  * pending events'' and the ``record my interest in future events''
 3290  * functions.  (These are done together, while the lock is held,
 3291  * to avoid race conditions.)
 3292  */
 3293 int
 3294 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
 3295 {
 3296 
 3297         v_addpollinfo(vp);
 3298         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3299         if (vp->v_pollinfo->vpi_revents & events) {
 3300                 /*
 3301                  * This leaves events we are not interested
 3302                  * in available for the other process which
 3303                  * which presumably had requested them
 3304                  * (otherwise they would never have been
 3305                  * recorded).
 3306                  */
 3307                 events &= vp->v_pollinfo->vpi_revents;
 3308                 vp->v_pollinfo->vpi_revents &= ~events;
 3309 
 3310                 mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3311                 return (events);
 3312         }
 3313         vp->v_pollinfo->vpi_events |= events;
 3314         selrecord(td, &vp->v_pollinfo->vpi_selinfo);
 3315         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3316         return (0);
 3317 }
 3318 
 3319 /*
 3320  * Routine to create and manage a filesystem syncer vnode.
 3321  */
 3322 #define sync_close ((int (*)(struct  vop_close_args *))nullop)
 3323 static int      sync_fsync(struct  vop_fsync_args *);
 3324 static int      sync_inactive(struct  vop_inactive_args *);
 3325 static int      sync_reclaim(struct  vop_reclaim_args *);
 3326 
 3327 static struct vop_vector sync_vnodeops = {
 3328         .vop_bypass =   VOP_EOPNOTSUPP,
 3329         .vop_close =    sync_close,             /* close */
 3330         .vop_fsync =    sync_fsync,             /* fsync */
 3331         .vop_inactive = sync_inactive,  /* inactive */
 3332         .vop_reclaim =  sync_reclaim,   /* reclaim */
 3333         .vop_lock1 =    vop_stdlock,    /* lock */
 3334         .vop_unlock =   vop_stdunlock,  /* unlock */
 3335         .vop_islocked = vop_stdislocked,        /* islocked */
 3336 };
 3337 
 3338 /*
 3339  * Create a new filesystem syncer vnode for the specified mount point.
 3340  */
 3341 int
 3342 vfs_allocate_syncvnode(struct mount *mp)
 3343 {
 3344         struct vnode *vp;
 3345         struct bufobj *bo;
 3346         static long start, incr, next;
 3347         int error;
 3348 
 3349         /* Allocate a new vnode */
 3350         if ((error = getnewvnode("syncer", mp, &sync_vnodeops, &vp)) != 0) {
 3351                 mp->mnt_syncer = NULL;
 3352                 return (error);
 3353         }
 3354         vp->v_type = VNON;
 3355         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3356         vp->v_vflag |= VV_FORCEINSMQ;
 3357         error = insmntque(vp, mp);
 3358         if (error != 0)
 3359                 panic("vfs_allocate_syncvnode: insmntque failed");
 3360         vp->v_vflag &= ~VV_FORCEINSMQ;
 3361         VOP_UNLOCK(vp, 0);
 3362         /*
 3363          * Place the vnode onto the syncer worklist. We attempt to
 3364          * scatter them about on the list so that they will go off
 3365          * at evenly distributed times even if all the filesystems
 3366          * are mounted at once.
 3367          */
 3368         next += incr;
 3369         if (next == 0 || next > syncer_maxdelay) {
 3370                 start /= 2;
 3371                 incr /= 2;
 3372                 if (start == 0) {
 3373                         start = syncer_maxdelay / 2;
 3374                         incr = syncer_maxdelay;
 3375                 }
 3376                 next = start;
 3377         }
 3378         bo = &vp->v_bufobj;
 3379         BO_LOCK(bo);
 3380         vn_syncer_add_to_worklist(bo, syncdelay > 0 ? next % syncdelay : 0);
 3381         /* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
 3382         mtx_lock(&sync_mtx);
 3383         sync_vnode_count++;
 3384         mtx_unlock(&sync_mtx);
 3385         BO_UNLOCK(bo);
 3386         mp->mnt_syncer = vp;
 3387         return (0);
 3388 }
 3389 
 3390 /*
 3391  * Do a lazy sync of the filesystem.
 3392  */
 3393 static int
 3394 sync_fsync(struct vop_fsync_args *ap)
 3395 {
 3396         struct vnode *syncvp = ap->a_vp;
 3397         struct mount *mp = syncvp->v_mount;
 3398         int error;
 3399         struct bufobj *bo;
 3400 
 3401         /*
 3402          * We only need to do something if this is a lazy evaluation.
 3403          */
 3404         if (ap->a_waitfor != MNT_LAZY)
 3405                 return (0);
 3406 
 3407         /*
 3408          * Move ourselves to the back of the sync list.
 3409          */
 3410         bo = &syncvp->v_bufobj;
 3411         BO_LOCK(bo);
 3412         vn_syncer_add_to_worklist(bo, syncdelay);
 3413         BO_UNLOCK(bo);
 3414 
 3415         /*
 3416          * Walk the list of vnodes pushing all that are dirty and
 3417          * not already on the sync list.
 3418          */
 3419         mtx_lock(&mountlist_mtx);
 3420         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK) != 0) {
 3421                 mtx_unlock(&mountlist_mtx);
 3422                 return (0);
 3423         }
 3424         if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
 3425                 vfs_unbusy(mp);
 3426                 return (0);
 3427         }
 3428         MNT_ILOCK(mp);
 3429         mp->mnt_noasync++;
 3430         mp->mnt_kern_flag &= ~MNTK_ASYNC;
 3431         MNT_IUNLOCK(mp);
 3432         vfs_msync(mp, MNT_NOWAIT);
 3433         error = VFS_SYNC(mp, MNT_LAZY);
 3434         MNT_ILOCK(mp);
 3435         mp->mnt_noasync--;
 3436         if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
 3437                 mp->mnt_kern_flag |= MNTK_ASYNC;
 3438         MNT_IUNLOCK(mp);
 3439         vn_finished_write(mp);
 3440         vfs_unbusy(mp);
 3441         return (error);
 3442 }
 3443 
 3444 /*
 3445  * The syncer vnode is no referenced.
 3446  */
 3447 static int
 3448 sync_inactive(struct vop_inactive_args *ap)
 3449 {
 3450 
 3451         vgone(ap->a_vp);
 3452         return (0);
 3453 }
 3454 
 3455 /*
 3456  * The syncer vnode is no longer needed and is being decommissioned.
 3457  *
 3458  * Modifications to the worklist must be protected by sync_mtx.
 3459  */
 3460 static int
 3461 sync_reclaim(struct vop_reclaim_args *ap)
 3462 {
 3463         struct vnode *vp = ap->a_vp;
 3464         struct bufobj *bo;
 3465 
 3466         bo = &vp->v_bufobj;
 3467         BO_LOCK(bo);
 3468         vp->v_mount->mnt_syncer = NULL;
 3469         if (bo->bo_flag & BO_ONWORKLST) {
 3470                 mtx_lock(&sync_mtx);
 3471                 LIST_REMOVE(bo, bo_synclist);
 3472                 syncer_worklist_len--;
 3473                 sync_vnode_count--;
 3474                 mtx_unlock(&sync_mtx);
 3475                 bo->bo_flag &= ~BO_ONWORKLST;
 3476         }
 3477         BO_UNLOCK(bo);
 3478 
 3479         return (0);
 3480 }
 3481 
 3482 /*
 3483  * Check if vnode represents a disk device
 3484  */
 3485 int
 3486 vn_isdisk(struct vnode *vp, int *errp)
 3487 {
 3488         int error;
 3489 
 3490         error = 0;
 3491         dev_lock();
 3492         if (vp->v_type != VCHR)
 3493                 error = ENOTBLK;
 3494         else if (vp->v_rdev == NULL)
 3495                 error = ENXIO;
 3496         else if (vp->v_rdev->si_devsw == NULL)
 3497                 error = ENXIO;
 3498         else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
 3499                 error = ENOTBLK;
 3500         dev_unlock();
 3501         if (errp != NULL)
 3502                 *errp = error;
 3503         return (error == 0);
 3504 }
 3505 
 3506 /*
 3507  * Common filesystem object access control check routine.  Accepts a
 3508  * vnode's type, "mode", uid and gid, requested access mode, credentials,
 3509  * and optional call-by-reference privused argument allowing vaccess()
 3510  * to indicate to the caller whether privilege was used to satisfy the
 3511  * request (obsoleted).  Returns 0 on success, or an errno on failure.
 3512  *
 3513  * The ifdef'd CAPABILITIES version is here for reference, but is not
 3514  * actually used.
 3515  */
 3516 int
 3517 vaccess(enum vtype type, mode_t file_mode, uid_t file_uid, gid_t file_gid,
 3518     accmode_t accmode, struct ucred *cred, int *privused)
 3519 {
 3520         accmode_t dac_granted;
 3521         accmode_t priv_granted;
 3522 
 3523         /*
 3524          * Look for a normal, non-privileged way to access the file/directory
 3525          * as requested.  If it exists, go with that.
 3526          */
 3527 
 3528         if (privused != NULL)
 3529                 *privused = 0;
 3530 
 3531         dac_granted = 0;
 3532 
 3533         /* Check the owner. */
 3534         if (cred->cr_uid == file_uid) {
 3535                 dac_granted |= VADMIN;
 3536                 if (file_mode & S_IXUSR)
 3537                         dac_granted |= VEXEC;
 3538                 if (file_mode & S_IRUSR)
 3539                         dac_granted |= VREAD;
 3540                 if (file_mode & S_IWUSR)
 3541                         dac_granted |= (VWRITE | VAPPEND);
 3542 
 3543                 if ((accmode & dac_granted) == accmode)
 3544                         return (0);
 3545 
 3546                 goto privcheck;
 3547         }
 3548 
 3549         /* Otherwise, check the groups (first match) */
 3550         if (groupmember(file_gid, cred)) {
 3551                 if (file_mode & S_IXGRP)
 3552                         dac_granted |= VEXEC;
 3553                 if (file_mode & S_IRGRP)
 3554                         dac_granted |= VREAD;
 3555                 if (file_mode & S_IWGRP)
 3556                         dac_granted |= (VWRITE | VAPPEND);
 3557 
 3558                 if ((accmode & dac_granted) == accmode)
 3559                         return (0);
 3560 
 3561                 goto privcheck;
 3562         }
 3563 
 3564         /* Otherwise, check everyone else. */
 3565         if (file_mode & S_IXOTH)
 3566                 dac_granted |= VEXEC;
 3567         if (file_mode & S_IROTH)
 3568                 dac_granted |= VREAD;
 3569         if (file_mode & S_IWOTH)
 3570                 dac_granted |= (VWRITE | VAPPEND);
 3571         if ((accmode & dac_granted) == accmode)
 3572                 return (0);
 3573 
 3574 privcheck:
 3575         /*
 3576          * Build a privilege mask to determine if the set of privileges
 3577          * satisfies the requirements when combined with the granted mask
 3578          * from above.  For each privilege, if the privilege is required,
 3579          * bitwise or the request type onto the priv_granted mask.
 3580          */
 3581         priv_granted = 0;
 3582 
 3583         if (type == VDIR) {
 3584                 /*
 3585                  * For directories, use PRIV_VFS_LOOKUP to satisfy VEXEC
 3586                  * requests, instead of PRIV_VFS_EXEC.
 3587                  */
 3588                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3589                     !priv_check_cred(cred, PRIV_VFS_LOOKUP, 0))
 3590                         priv_granted |= VEXEC;
 3591         } else {
 3592                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3593                     !priv_check_cred(cred, PRIV_VFS_EXEC, 0))
 3594                         priv_granted |= VEXEC;
 3595         }
 3596 
 3597         if ((accmode & VREAD) && ((dac_granted & VREAD) == 0) &&
 3598             !priv_check_cred(cred, PRIV_VFS_READ, 0))
 3599                 priv_granted |= VREAD;
 3600 
 3601         if ((accmode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
 3602             !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
 3603                 priv_granted |= (VWRITE | VAPPEND);
 3604 
 3605         if ((accmode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
 3606             !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
 3607                 priv_granted |= VADMIN;
 3608 
 3609         if ((accmode & (priv_granted | dac_granted)) == accmode) {
 3610                 /* XXX audit: privilege used */
 3611                 if (privused != NULL)
 3612                         *privused = 1;
 3613                 return (0);
 3614         }
 3615 
 3616         return ((accmode & VADMIN) ? EPERM : EACCES);
 3617 }
 3618 
 3619 /*
 3620  * Credential check based on process requesting service, and per-attribute
 3621  * permissions.
 3622  */
 3623 int
 3624 extattr_check_cred(struct vnode *vp, int attrnamespace, struct ucred *cred,
 3625     struct thread *td, accmode_t accmode)
 3626 {
 3627 
 3628         /*
 3629          * Kernel-invoked always succeeds.
 3630          */
 3631         if (cred == NOCRED)
 3632                 return (0);
 3633 
 3634         /*
 3635          * Do not allow privileged processes in jail to directly manipulate
 3636          * system attributes.
 3637          */
 3638         switch (attrnamespace) {
 3639         case EXTATTR_NAMESPACE_SYSTEM:
 3640                 /* Potentially should be: return (EPERM); */
 3641                 return (priv_check_cred(cred, PRIV_VFS_EXTATTR_SYSTEM, 0));
 3642         case EXTATTR_NAMESPACE_USER:
 3643                 return (VOP_ACCESS(vp, accmode, cred, td));
 3644         default:
 3645                 return (EPERM);
 3646         }
 3647 }
 3648 
 3649 #ifdef DEBUG_VFS_LOCKS
 3650 /*
 3651  * This only exists to supress warnings from unlocked specfs accesses.  It is
 3652  * no longer ok to have an unlocked VFS.
 3653  */
 3654 #define IGNORE_LOCK(vp) (panicstr != NULL || (vp) == NULL ||            \
 3655         (vp)->v_type == VCHR || (vp)->v_type == VBAD)
 3656 
 3657 int vfs_badlock_ddb = 1;        /* Drop into debugger on violation. */
 3658 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0, "");
 3659 
 3660 int vfs_badlock_mutex = 1;      /* Check for interlock across VOPs. */
 3661 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex, 0, "");
 3662 
 3663 int vfs_badlock_print = 1;      /* Print lock violations. */
 3664 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print, 0, "");
 3665 
 3666 #ifdef KDB
 3667 int vfs_badlock_backtrace = 1;  /* Print backtrace at lock violations. */
 3668 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW, &vfs_badlock_backtrace, 0, "");
 3669 #endif
 3670 
 3671 static void
 3672 vfs_badlock(const char *msg, const char *str, struct vnode *vp)
 3673 {
 3674 
 3675 #ifdef KDB
 3676         if (vfs_badlock_backtrace)
 3677                 kdb_backtrace();
 3678 #endif
 3679         if (vfs_badlock_print)
 3680                 printf("%s: %p %s\n", str, (void *)vp, msg);
 3681         if (vfs_badlock_ddb)
 3682                 kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3683 }
 3684 
 3685 void
 3686 assert_vi_locked(struct vnode *vp, const char *str)
 3687 {
 3688 
 3689         if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
 3690                 vfs_badlock("interlock is not locked but should be", str, vp);
 3691 }
 3692 
 3693 void
 3694 assert_vi_unlocked(struct vnode *vp, const char *str)
 3695 {
 3696 
 3697         if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
 3698                 vfs_badlock("interlock is locked but should not be", str, vp);
 3699 }
 3700 
 3701 void
 3702 assert_vop_locked(struct vnode *vp, const char *str)
 3703 {
 3704 
 3705         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == 0)
 3706                 vfs_badlock("is not locked but should be", str, vp);
 3707 }
 3708 
 3709 void
 3710 assert_vop_unlocked(struct vnode *vp, const char *str)
 3711 {
 3712 
 3713         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
 3714                 vfs_badlock("is locked but should not be", str, vp);
 3715 }
 3716 
 3717 void
 3718 assert_vop_elocked(struct vnode *vp, const char *str)
 3719 {
 3720 
 3721         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 3722                 vfs_badlock("is not exclusive locked but should be", str, vp);
 3723 }
 3724 
 3725 #if 0
 3726 void
 3727 assert_vop_elocked_other(struct vnode *vp, const char *str)
 3728 {
 3729 
 3730         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLOTHER)
 3731                 vfs_badlock("is not exclusive locked by another thread",
 3732                     str, vp);
 3733 }
 3734 
 3735 void
 3736 assert_vop_slocked(struct vnode *vp, const char *str)
 3737 {
 3738 
 3739         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_SHARED)
 3740                 vfs_badlock("is not locked shared but should be", str, vp);
 3741 }
 3742 #endif /* 0 */
 3743 #endif /* DEBUG_VFS_LOCKS */
 3744 
 3745 void
 3746 vop_rename_pre(void *ap)
 3747 {
 3748         struct vop_rename_args *a = ap;
 3749 
 3750 #ifdef DEBUG_VFS_LOCKS
 3751         if (a->a_tvp)
 3752                 ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
 3753         ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
 3754         ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
 3755         ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
 3756 
 3757         /* Check the source (from). */
 3758         if (a->a_tdvp != a->a_fdvp && a->a_tvp != a->a_fdvp)
 3759                 ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
 3760         if (a->a_tvp != a->a_fvp)
 3761                 ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: fvp locked");
 3762 
 3763         /* Check the target. */
 3764         if (a->a_tvp)
 3765                 ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
 3766         ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
 3767 #endif
 3768         if (a->a_tdvp != a->a_fdvp)
 3769                 vhold(a->a_fdvp);
 3770         if (a->a_tvp != a->a_fvp)
 3771                 vhold(a->a_fvp);
 3772         vhold(a->a_tdvp);
 3773         if (a->a_tvp)
 3774                 vhold(a->a_tvp);
 3775 }
 3776 
 3777 void
 3778 vop_strategy_pre(void *ap)
 3779 {
 3780 #ifdef DEBUG_VFS_LOCKS
 3781         struct vop_strategy_args *a;
 3782         struct buf *bp;
 3783 
 3784         a = ap;
 3785         bp = a->a_bp;
 3786 
 3787         /*
 3788          * Cluster ops lock their component buffers but not the IO container.
 3789          */
 3790         if ((bp->b_flags & B_CLUSTER) != 0)
 3791                 return;
 3792 
 3793         if (!BUF_ISLOCKED(bp)) {
 3794                 if (vfs_badlock_print)
 3795                         printf(
 3796                             "VOP_STRATEGY: bp is not locked but should be\n");
 3797                 if (vfs_badlock_ddb)
 3798                         kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3799         }
 3800 #endif
 3801 }
 3802 
 3803 void
 3804 vop_lookup_pre(void *ap)
 3805 {
 3806 #ifdef DEBUG_VFS_LOCKS
 3807         struct vop_lookup_args *a;
 3808         struct vnode *dvp;
 3809 
 3810         a = ap;
 3811         dvp = a->a_dvp;
 3812         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
 3813         ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
 3814 #endif
 3815 }
 3816 
 3817 void
 3818 vop_lookup_post(void *ap, int rc)
 3819 {
 3820 #ifdef DEBUG_VFS_LOCKS
 3821         struct vop_lookup_args *a;
 3822         struct vnode *dvp;
 3823         struct vnode *vp;
 3824 
 3825         a = ap;
 3826         dvp = a->a_dvp;
 3827         vp = *(a->a_vpp);
 3828 
 3829         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
 3830         ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
 3831 
 3832         if (!rc)
 3833                 ASSERT_VOP_LOCKED(vp, "VOP_LOOKUP (child)");
 3834 #endif
 3835 }
 3836 
 3837 void
 3838 vop_lock_pre(void *ap)
 3839 {
 3840 #ifdef DEBUG_VFS_LOCKS
 3841         struct vop_lock1_args *a = ap;
 3842 
 3843         if ((a->a_flags & LK_INTERLOCK) == 0)
 3844                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 3845         else
 3846                 ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
 3847 #endif
 3848 }
 3849 
 3850 void
 3851 vop_lock_post(void *ap, int rc)
 3852 {
 3853 #ifdef DEBUG_VFS_LOCKS
 3854         struct vop_lock1_args *a = ap;
 3855 
 3856         ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 3857         if (rc == 0)
 3858                 ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
 3859 #endif
 3860 }
 3861 
 3862 void
 3863 vop_unlock_pre(void *ap)
 3864 {
 3865 #ifdef DEBUG_VFS_LOCKS
 3866         struct vop_unlock_args *a = ap;
 3867 
 3868         if (a->a_flags & LK_INTERLOCK)
 3869                 ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
 3870         ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
 3871 #endif
 3872 }
 3873 
 3874 void
 3875 vop_unlock_post(void *ap, int rc)
 3876 {
 3877 #ifdef DEBUG_VFS_LOCKS
 3878         struct vop_unlock_args *a = ap;
 3879 
 3880         if (a->a_flags & LK_INTERLOCK)
 3881                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
 3882 #endif
 3883 }
 3884 
 3885 void
 3886 vop_create_post(void *ap, int rc)
 3887 {
 3888         struct vop_create_args *a = ap;
 3889 
 3890         if (!rc)
 3891                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 3892 }
 3893 
 3894 void
 3895 vop_link_post(void *ap, int rc)
 3896 {
 3897         struct vop_link_args *a = ap;
 3898 
 3899         if (!rc) {
 3900                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_LINK);
 3901                 VFS_KNOTE_LOCKED(a->a_tdvp, NOTE_WRITE);
 3902         }
 3903 }
 3904 
 3905 void
 3906 vop_mkdir_post(void *ap, int rc)
 3907 {
 3908         struct vop_mkdir_args *a = ap;
 3909 
 3910         if (!rc)
 3911                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 3912 }
 3913 
 3914 void
 3915 vop_mknod_post(void *ap, int rc)
 3916 {
 3917         struct vop_mknod_args *a = ap;
 3918 
 3919         if (!rc)
 3920                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 3921 }
 3922 
 3923 void
 3924 vop_remove_post(void *ap, int rc)
 3925 {
 3926         struct vop_remove_args *a = ap;
 3927 
 3928         if (!rc) {
 3929                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 3930                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 3931         }
 3932 }
 3933 
 3934 void
 3935 vop_rename_post(void *ap, int rc)
 3936 {
 3937         struct vop_rename_args *a = ap;
 3938 
 3939         if (!rc) {
 3940                 VFS_KNOTE_UNLOCKED(a->a_fdvp, NOTE_WRITE);
 3941                 VFS_KNOTE_UNLOCKED(a->a_tdvp, NOTE_WRITE);
 3942                 VFS_KNOTE_UNLOCKED(a->a_fvp, NOTE_RENAME);
 3943                 if (a->a_tvp)
 3944                         VFS_KNOTE_UNLOCKED(a->a_tvp, NOTE_DELETE);
 3945         }
 3946         if (a->a_tdvp != a->a_fdvp)
 3947                 vdrop(a->a_fdvp);
 3948         if (a->a_tvp != a->a_fvp)
 3949                 vdrop(a->a_fvp);
 3950         vdrop(a->a_tdvp);
 3951         if (a->a_tvp)
 3952                 vdrop(a->a_tvp);
 3953 }
 3954 
 3955 void
 3956 vop_rmdir_post(void *ap, int rc)
 3957 {
 3958         struct vop_rmdir_args *a = ap;
 3959 
 3960         if (!rc) {
 3961                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 3962                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 3963         }
 3964 }
 3965 
 3966 void
 3967 vop_setattr_post(void *ap, int rc)
 3968 {
 3969         struct vop_setattr_args *a = ap;
 3970 
 3971         if (!rc)
 3972                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 3973 }
 3974 
 3975 void
 3976 vop_symlink_post(void *ap, int rc)
 3977 {
 3978         struct vop_symlink_args *a = ap;
 3979 
 3980         if (!rc)
 3981                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 3982 }
 3983 
 3984 static struct knlist fs_knlist;
 3985 
 3986 static void
 3987 vfs_event_init(void *arg)
 3988 {
 3989         knlist_init_mtx(&fs_knlist, NULL);
 3990 }
 3991 /* XXX - correct order? */
 3992 SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
 3993 
 3994 void
 3995 vfs_event_signal(fsid_t *fsid, u_int32_t event, intptr_t data __unused)
 3996 {
 3997 
 3998         KNOTE_UNLOCKED(&fs_knlist, event);
 3999 }
 4000 
 4001 static int      filt_fsattach(struct knote *kn);
 4002 static void     filt_fsdetach(struct knote *kn);
 4003 static int      filt_fsevent(struct knote *kn, long hint);
 4004 
 4005 struct filterops fs_filtops =
 4006         { 0, filt_fsattach, filt_fsdetach, filt_fsevent };
 4007 
 4008 static int
 4009 filt_fsattach(struct knote *kn)
 4010 {
 4011 
 4012         kn->kn_flags |= EV_CLEAR;
 4013         knlist_add(&fs_knlist, kn, 0);
 4014         return (0);
 4015 }
 4016 
 4017 static void
 4018 filt_fsdetach(struct knote *kn)
 4019 {
 4020 
 4021         knlist_remove(&fs_knlist, kn, 0);
 4022 }
 4023 
 4024 static int
 4025 filt_fsevent(struct knote *kn, long hint)
 4026 {
 4027 
 4028         kn->kn_fflags |= hint;
 4029         return (kn->kn_fflags != 0);
 4030 }
 4031 
 4032 static int
 4033 sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
 4034 {
 4035         struct vfsidctl vc;
 4036         int error;
 4037         struct mount *mp;
 4038 
 4039         error = SYSCTL_IN(req, &vc, sizeof(vc));
 4040         if (error)
 4041                 return (error);
 4042         if (vc.vc_vers != VFS_CTL_VERS1)
 4043                 return (EINVAL);
 4044         mp = vfs_getvfs(&vc.vc_fsid);
 4045         if (mp == NULL)
 4046                 return (ENOENT);
 4047         /* ensure that a specific sysctl goes to the right filesystem. */
 4048         if (strcmp(vc.vc_fstypename, "*") != 0 &&
 4049             strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
 4050                 vfs_rel(mp);
 4051                 return (EINVAL);
 4052         }
 4053         VCTLTOREQ(&vc, req);
 4054         error = VFS_SYSCTL(mp, vc.vc_op, req);
 4055         vfs_rel(mp);
 4056         return (error);
 4057 }
 4058 
 4059 SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLFLAG_WR, NULL, 0, sysctl_vfs_ctl, "",
 4060     "Sysctl by fsid");
 4061 
 4062 /*
 4063  * Function to initialize a va_filerev field sensibly.
 4064  * XXX: Wouldn't a random number make a lot more sense ??
 4065  */
 4066 u_quad_t
 4067 init_va_filerev(void)
 4068 {
 4069         struct bintime bt;
 4070 
 4071         getbinuptime(&bt);
 4072         return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
 4073 }
 4074 
 4075 static int      filt_vfsread(struct knote *kn, long hint);
 4076 static int      filt_vfswrite(struct knote *kn, long hint);
 4077 static int      filt_vfsvnode(struct knote *kn, long hint);
 4078 static void     filt_vfsdetach(struct knote *kn);
 4079 static struct filterops vfsread_filtops =
 4080         { 1, NULL, filt_vfsdetach, filt_vfsread };
 4081 static struct filterops vfswrite_filtops =
 4082         { 1, NULL, filt_vfsdetach, filt_vfswrite };
 4083 static struct filterops vfsvnode_filtops =
 4084         { 1, NULL, filt_vfsdetach, filt_vfsvnode };
 4085 
 4086 static void
 4087 vfs_knllock(void *arg)
 4088 {
 4089         struct vnode *vp = arg;
 4090 
 4091         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 4092 }
 4093 
 4094 static void
 4095 vfs_knlunlock(void *arg)
 4096 {
 4097         struct vnode *vp = arg;
 4098 
 4099         VOP_UNLOCK(vp, 0);
 4100 }
 4101 
 4102 static void
 4103 vfs_knl_assert_locked(void *arg)
 4104 {
 4105 #ifdef DEBUG_VFS_LOCKS
 4106         struct vnode *vp = arg;
 4107 
 4108         ASSERT_VOP_LOCKED(vp, "vfs_knl_assert_locked");
 4109 #endif
 4110 }
 4111 
 4112 static void
 4113 vfs_knl_assert_unlocked(void *arg)
 4114 {
 4115 #ifdef DEBUG_VFS_LOCKS
 4116         struct vnode *vp = arg;
 4117 
 4118         ASSERT_VOP_UNLOCKED(vp, "vfs_knl_assert_unlocked");
 4119 #endif
 4120 }
 4121 
 4122 int
 4123 vfs_kqfilter(struct vop_kqfilter_args *ap)
 4124 {
 4125         struct vnode *vp = ap->a_vp;
 4126         struct knote *kn = ap->a_kn;
 4127         struct knlist *knl;
 4128 
 4129         switch (kn->kn_filter) {
 4130         case EVFILT_READ:
 4131                 kn->kn_fop = &vfsread_filtops;
 4132                 break;
 4133         case EVFILT_WRITE:
 4134                 kn->kn_fop = &vfswrite_filtops;
 4135                 break;
 4136         case EVFILT_VNODE:
 4137                 kn->kn_fop = &vfsvnode_filtops;
 4138                 break;
 4139         default:
 4140                 return (EINVAL);
 4141         }
 4142 
 4143         kn->kn_hook = (caddr_t)vp;
 4144 
 4145         v_addpollinfo(vp);
 4146         if (vp->v_pollinfo == NULL)
 4147                 return (ENOMEM);
 4148         knl = &vp->v_pollinfo->vpi_selinfo.si_note;
 4149         knlist_add(knl, kn, 0);
 4150 
 4151         return (0);
 4152 }
 4153 
 4154 /*
 4155  * Detach knote from vnode
 4156  */
 4157 static void
 4158 filt_vfsdetach(struct knote *kn)
 4159 {
 4160         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4161 
 4162         KASSERT(vp->v_pollinfo != NULL, ("Missing v_pollinfo"));
 4163         knlist_remove(&vp->v_pollinfo->vpi_selinfo.si_note, kn, 0);
 4164 }
 4165 
 4166 /*ARGSUSED*/
 4167 static int
 4168 filt_vfsread(struct knote *kn, long hint)
 4169 {
 4170         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4171         struct vattr va;
 4172         int res;
 4173 
 4174         /*
 4175          * filesystem is gone, so set the EOF flag and schedule
 4176          * the knote for deletion.
 4177          */
 4178         if (hint == NOTE_REVOKE) {
 4179                 VI_LOCK(vp);
 4180                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4181                 VI_UNLOCK(vp);
 4182                 return (1);
 4183         }
 4184 
 4185         if (VOP_GETATTR(vp, &va, curthread->td_ucred))
 4186                 return (0);
 4187 
 4188         VI_LOCK(vp);
 4189         kn->kn_data = va.va_size - kn->kn_fp->f_offset;
 4190         res = (kn->kn_data != 0);
 4191         VI_UNLOCK(vp);
 4192         return (res);
 4193 }
 4194 
 4195 /*ARGSUSED*/
 4196 static int
 4197 filt_vfswrite(struct knote *kn, long hint)
 4198 {
 4199         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4200 
 4201         VI_LOCK(vp);
 4202 
 4203         /*
 4204          * filesystem is gone, so set the EOF flag and schedule
 4205          * the knote for deletion.
 4206          */
 4207         if (hint == NOTE_REVOKE)
 4208                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4209 
 4210         kn->kn_data = 0;
 4211         VI_UNLOCK(vp);
 4212         return (1);
 4213 }
 4214 
 4215 static int
 4216 filt_vfsvnode(struct knote *kn, long hint)
 4217 {
 4218         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4219         int res;
 4220 
 4221         VI_LOCK(vp);
 4222         if (kn->kn_sfflags & hint)
 4223                 kn->kn_fflags |= hint;
 4224         if (hint == NOTE_REVOKE) {
 4225                 kn->kn_flags |= EV_EOF;
 4226                 VI_UNLOCK(vp);
 4227                 return (1);
 4228         }
 4229         res = (kn->kn_fflags != 0);
 4230         VI_UNLOCK(vp);
 4231         return (res);
 4232 }
 4233 
 4234 int
 4235 vfs_read_dirent(struct vop_readdir_args *ap, struct dirent *dp, off_t off)
 4236 {
 4237         int error;
 4238 
 4239         if (dp->d_reclen > ap->a_uio->uio_resid)
 4240                 return (ENAMETOOLONG);
 4241         error = uiomove(dp, dp->d_reclen, ap->a_uio);
 4242         if (error) {
 4243                 if (ap->a_ncookies != NULL) {
 4244                         if (ap->a_cookies != NULL)
 4245                                 free(ap->a_cookies, M_TEMP);
 4246                         ap->a_cookies = NULL;
 4247                         *ap->a_ncookies = 0;
 4248                 }
 4249                 return (error);
 4250         }
 4251         if (ap->a_ncookies == NULL)
 4252                 return (0);
 4253 
 4254         KASSERT(ap->a_cookies,
 4255             ("NULL ap->a_cookies value with non-NULL ap->a_ncookies!"));
 4256 
 4257         *ap->a_cookies = realloc(*ap->a_cookies,
 4258             (*ap->a_ncookies + 1) * sizeof(u_long), M_TEMP, M_WAITOK | M_ZERO);
 4259         (*ap->a_cookies)[*ap->a_ncookies] = off;
 4260         return (0);
 4261 }
 4262 
 4263 /*
 4264  * Mark for update the access time of the file if the filesystem
 4265  * supports VOP_MARKATIME.  This functionality is used by execve and
 4266  * mmap, so we want to avoid the I/O implied by directly setting
 4267  * va_atime for the sake of efficiency.
 4268  */
 4269 void
 4270 vfs_mark_atime(struct vnode *vp, struct ucred *cred)
 4271 {
 4272         struct mount *mp;
 4273 
 4274         mp = vp->v_mount;
 4275         VFS_ASSERT_GIANT(mp);
 4276         ASSERT_VOP_LOCKED(vp, "vfs_mark_atime");
 4277         if (mp != NULL && (mp->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0)
 4278                 (void)VOP_MARKATIME(vp);
 4279 }
 4280 
 4281 /*
 4282  * The purpose of this routine is to remove granularity from accmode_t,
 4283  * reducing it into standard unix access bits - VEXEC, VREAD, VWRITE,
 4284  * VADMIN and VAPPEND.
 4285  *
 4286  * If it returns 0, the caller is supposed to continue with the usual
 4287  * access checks using 'accmode' as modified by this routine.  If it
 4288  * returns nonzero value, the caller is supposed to return that value
 4289  * as errno.
 4290  *
 4291  * Note that after this routine runs, accmode may be zero.
 4292  */
 4293 int
 4294 vfs_unixify_accmode(accmode_t *accmode)
 4295 {
 4296         /*
 4297          * There is no way to specify explicit "deny" rule using
 4298          * file mode or POSIX.1e ACLs.
 4299          */
 4300         if (*accmode & VEXPLICIT_DENY) {
 4301                 *accmode = 0;
 4302                 return (0);
 4303         }
 4304 
 4305         /*
 4306          * None of these can be translated into usual access bits.
 4307          * Also, the common case for NFSv4 ACLs is to not contain
 4308          * either of these bits. Caller should check for VWRITE
 4309          * on the containing directory instead.
 4310          */
 4311         if (*accmode & (VDELETE_CHILD | VDELETE))
 4312                 return (EPERM);
 4313 
 4314         if (*accmode & VADMIN_PERMS) {
 4315                 *accmode &= ~VADMIN_PERMS;
 4316                 *accmode |= VADMIN;
 4317         }
 4318 
 4319         /*
 4320          * There is no way to deny VREAD_ATTRIBUTES, VREAD_ACL
 4321          * or VSYNCHRONIZE using file mode or POSIX.1e ACL.
 4322          */
 4323         *accmode &= ~(VSTAT_PERMS | VSYNCHRONIZE);
 4324 
 4325         return (0);
 4326 }

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