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/8.4/sys/kern/vfs_subr.c 249524 2013-04-15 19:45:09Z smh $");
   43 
   44 #include "opt_compat.h"
   45 #include "opt_ddb.h"
   46 #include "opt_watchdog.h"
   47 
   48 #include <sys/param.h>
   49 #include <sys/systm.h>
   50 #include <sys/bio.h>
   51 #include <sys/buf.h>
   52 #include <sys/condvar.h>
   53 #include <sys/conf.h>
   54 #include <sys/dirent.h>
   55 #include <sys/event.h>
   56 #include <sys/eventhandler.h>
   57 #include <sys/extattr.h>
   58 #include <sys/file.h>
   59 #include <sys/fcntl.h>
   60 #include <sys/jail.h>
   61 #include <sys/kdb.h>
   62 #include <sys/kernel.h>
   63 #include <sys/kthread.h>
   64 #include <sys/lockf.h>
   65 #include <sys/malloc.h>
   66 #include <sys/mount.h>
   67 #include <sys/namei.h>
   68 #include <sys/priv.h>
   69 #include <sys/reboot.h>
   70 #include <sys/sched.h>
   71 #include <sys/sleepqueue.h>
   72 #include <sys/stat.h>
   73 #include <sys/sysctl.h>
   74 #include <sys/syslog.h>
   75 #include <sys/vmmeter.h>
   76 #include <sys/vnode.h>
   77 #include <sys/watchdog.h>
   78 
   79 #include <machine/stdarg.h>
   80 
   81 #include <security/mac/mac_framework.h>
   82 
   83 #include <vm/vm.h>
   84 #include <vm/vm_object.h>
   85 #include <vm/vm_extern.h>
   86 #include <vm/pmap.h>
   87 #include <vm/vm_map.h>
   88 #include <vm/vm_page.h>
   89 #include <vm/vm_kern.h>
   90 #include <vm/uma.h>
   91 
   92 #ifdef DDB
   93 #include <ddb/ddb.h>
   94 #endif
   95 
   96 #define WI_MPSAFEQ      0
   97 #define WI_GIANTQ       1
   98 
   99 static void     delmntque(struct vnode *vp);
  100 static int      flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo,
  101                     int slpflag, int slptimeo);
  102 static void     syncer_shutdown(void *arg, int howto);
  103 static int      vtryrecycle(struct vnode *vp);
  104 static void     vbusy(struct vnode *vp);
  105 static void     v_incr_usecount(struct vnode *);
  106 static void     v_decr_usecount(struct vnode *);
  107 static void     v_decr_useonly(struct vnode *);
  108 static void     v_upgrade_usecount(struct vnode *);
  109 static void     vfree(struct vnode *);
  110 static void     vnlru_free(int);
  111 static void     vgonel(struct vnode *);
  112 static void     vfs_knllock(void *arg);
  113 static void     vfs_knlunlock(void *arg);
  114 static void     vfs_knl_assert_locked(void *arg);
  115 static void     vfs_knl_assert_unlocked(void *arg);
  116 static void     destroy_vpollinfo(struct vpollinfo *vi);
  117 
  118 /*
  119  * Number of vnodes in existence.  Increased whenever getnewvnode()
  120  * allocates a new vnode, decreased on vdestroy() called on VI_DOOMed
  121  * vnode.
  122  */
  123 static unsigned long    numvnodes;
  124 
  125 SYSCTL_LONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
  126     "Number of vnodes in existence");
  127 
  128 /*
  129  * Conversion tables for conversion from vnode types to inode formats
  130  * and back.
  131  */
  132 enum vtype iftovt_tab[16] = {
  133         VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
  134         VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
  135 };
  136 int vttoif_tab[10] = {
  137         0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
  138         S_IFSOCK, S_IFIFO, S_IFMT, S_IFMT
  139 };
  140 
  141 /*
  142  * List of vnodes that are ready for recycling.
  143  */
  144 static TAILQ_HEAD(freelst, vnode) vnode_free_list;
  145 
  146 /*
  147  * Free vnode target.  Free vnodes may simply be files which have been stat'd
  148  * but not read.  This is somewhat common, and a small cache of such files
  149  * should be kept to avoid recreation costs.
  150  */
  151 static u_long wantfreevnodes;
  152 SYSCTL_LONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
  153 /* Number of vnodes in the free list. */
  154 static u_long freevnodes;
  155 SYSCTL_LONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0,
  156     "Number of vnodes in the free list");
  157 
  158 static int vlru_allow_cache_src;
  159 SYSCTL_INT(_vfs, OID_AUTO, vlru_allow_cache_src, CTLFLAG_RW,
  160     &vlru_allow_cache_src, 0, "Allow vlru to reclaim source vnode");
  161 
  162 /*
  163  * Various variables used for debugging the new implementation of
  164  * reassignbuf().
  165  * XXX these are probably of (very) limited utility now.
  166  */
  167 static int reassignbufcalls;
  168 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0,
  169     "Number of calls to reassignbuf");
  170 
  171 /*
  172  * Cache for the mount type id assigned to NFS.  This is used for
  173  * special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
  174  */
  175 int     nfs_mount_type = -1;
  176 
  177 /* To keep more than one thread at a time from running vfs_getnewfsid */
  178 static struct mtx mntid_mtx;
  179 
  180 /*
  181  * Lock for any access to the following:
  182  *      vnode_free_list
  183  *      numvnodes
  184  *      freevnodes
  185  */
  186 static struct mtx vnode_free_list_mtx;
  187 
  188 /* Publicly exported FS */
  189 struct nfs_public nfs_pub;
  190 
  191 /* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
  192 static uma_zone_t vnode_zone;
  193 static uma_zone_t vnodepoll_zone;
  194 
  195 /* Set to 1 to print out reclaim of active vnodes */
  196 int     prtactive;
  197 
  198 /*
  199  * The workitem queue.
  200  *
  201  * It is useful to delay writes of file data and filesystem metadata
  202  * for tens of seconds so that quickly created and deleted files need
  203  * not waste disk bandwidth being created and removed. To realize this,
  204  * we append vnodes to a "workitem" queue. When running with a soft
  205  * updates implementation, most pending metadata dependencies should
  206  * not wait for more than a few seconds. Thus, mounted on block devices
  207  * are delayed only about a half the time that file data is delayed.
  208  * Similarly, directory updates are more critical, so are only delayed
  209  * about a third the time that file data is delayed. Thus, there are
  210  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
  211  * one each second (driven off the filesystem syncer process). The
  212  * syncer_delayno variable indicates the next queue that is to be processed.
  213  * Items that need to be processed soon are placed in this queue:
  214  *
  215  *      syncer_workitem_pending[syncer_delayno]
  216  *
  217  * A delay of fifteen seconds is done by placing the request fifteen
  218  * entries later in the queue:
  219  *
  220  *      syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
  221  *
  222  */
  223 static int syncer_delayno;
  224 static long syncer_mask;
  225 LIST_HEAD(synclist, bufobj);
  226 static struct synclist *syncer_workitem_pending[2];
  227 /*
  228  * The sync_mtx protects:
  229  *      bo->bo_synclist
  230  *      sync_vnode_count
  231  *      syncer_delayno
  232  *      syncer_state
  233  *      syncer_workitem_pending
  234  *      syncer_worklist_len
  235  *      rushjob
  236  */
  237 static struct mtx sync_mtx;
  238 static struct cv sync_wakeup;
  239 
  240 #define SYNCER_MAXDELAY         32
  241 static int syncer_maxdelay = SYNCER_MAXDELAY;   /* maximum delay time */
  242 static int syncdelay = 30;              /* max time to delay syncing data */
  243 static int filedelay = 30;              /* time to delay syncing files */
  244 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0,
  245     "Time to delay syncing files (in seconds)");
  246 static int dirdelay = 29;               /* time to delay syncing directories */
  247 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0,
  248     "Time to delay syncing directories (in seconds)");
  249 static int metadelay = 28;              /* time to delay syncing metadata */
  250 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0,
  251     "Time to delay syncing metadata (in seconds)");
  252 static int rushjob;             /* number of slots to run ASAP */
  253 static int stat_rush_requests;  /* number of times I/O speeded up */
  254 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0,
  255     "Number of times I/O speeded up (rush requests)");
  256 
  257 /*
  258  * When shutting down the syncer, run it at four times normal speed.
  259  */
  260 #define SYNCER_SHUTDOWN_SPEEDUP         4
  261 static int sync_vnode_count;
  262 static int syncer_worklist_len;
  263 static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
  264     syncer_state;
  265 
  266 /*
  267  * Number of vnodes we want to exist at any one time.  This is mostly used
  268  * to size hash tables in vnode-related code.  It is normally not used in
  269  * getnewvnode(), as wantfreevnodes is normally nonzero.)
  270  *
  271  * XXX desiredvnodes is historical cruft and should not exist.
  272  */
  273 int desiredvnodes;
  274 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
  275     &desiredvnodes, 0, "Maximum number of vnodes");
  276 SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
  277     &wantfreevnodes, 0, "Minimum number of vnodes (legacy)");
  278 static int vnlru_nowhere;
  279 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
  280     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
  281 
  282 /*
  283  * Macros to control when a vnode is freed and recycled.  All require
  284  * the vnode interlock.
  285  */
  286 #define VCANRECYCLE(vp) (((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  287 #define VSHOULDFREE(vp) (!((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  288 #define VSHOULDBUSY(vp) (((vp)->v_iflag & VI_FREE) && (vp)->v_holdcnt)
  289 
  290 
  291 /*
  292  * Initialize the vnode management data structures.
  293  *
  294  * Reevaluate the following cap on the number of vnodes after the physical
  295  * memory size exceeds 512GB.  In the limit, as the physical memory size
  296  * grows, the ratio of physical pages to vnodes approaches sixteen to one.
  297  */
  298 #ifndef MAXVNODES_MAX
  299 #define MAXVNODES_MAX   (512 * (1024 * 1024 * 1024 / (int)PAGE_SIZE / 16))
  300 #endif
  301 static void
  302 vntblinit(void *dummy __unused)
  303 {
  304         int physvnodes, virtvnodes;
  305 
  306         /*
  307          * Desiredvnodes is a function of the physical memory size and the
  308          * kernel's heap size.  Generally speaking, it scales with the
  309          * physical memory size.  The ratio of desiredvnodes to physical pages
  310          * is one to four until desiredvnodes exceeds 98,304.  Thereafter, the
  311          * marginal ratio of desiredvnodes to physical pages is one to
  312          * sixteen.  However, desiredvnodes is limited by the kernel's heap
  313          * size.  The memory required by desiredvnodes vnodes and vm objects
  314          * may not exceed one seventh of the kernel's heap size.
  315          */
  316         physvnodes = maxproc + cnt.v_page_count / 16 + 3 * min(98304 * 4,
  317             cnt.v_page_count) / 16;
  318         virtvnodes = vm_kmem_size / (7 * (sizeof(struct vm_object) +
  319             sizeof(struct vnode)));
  320         desiredvnodes = min(physvnodes, virtvnodes);
  321         if (desiredvnodes > MAXVNODES_MAX) {
  322                 if (bootverbose)
  323                         printf("Reducing kern.maxvnodes %d -> %d\n",
  324                             desiredvnodes, MAXVNODES_MAX);
  325                 desiredvnodes = MAXVNODES_MAX;
  326         }
  327         wantfreevnodes = desiredvnodes / 4;
  328         mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
  329         TAILQ_INIT(&vnode_free_list);
  330         mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
  331         vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
  332             NULL, NULL, UMA_ALIGN_PTR, 0);
  333         vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
  334             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  335         /*
  336          * Initialize the filesystem syncer.
  337          */
  338         syncer_workitem_pending[WI_MPSAFEQ] = hashinit(syncer_maxdelay, M_VNODE,
  339             &syncer_mask);
  340         syncer_workitem_pending[WI_GIANTQ] = hashinit(syncer_maxdelay, M_VNODE,
  341             &syncer_mask);
  342         syncer_maxdelay = syncer_mask + 1;
  343         mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
  344         cv_init(&sync_wakeup, "syncer");
  345 }
  346 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL);
  347 
  348 
  349 /*
  350  * Mark a mount point as busy. Used to synchronize access and to delay
  351  * unmounting. Eventually, mountlist_mtx is not released on failure.
  352  *
  353  * vfs_busy() is a custom lock, it can block the caller.
  354  * vfs_busy() only sleeps if the unmount is active on the mount point.
  355  * For a mountpoint mp, vfs_busy-enforced lock is before lock of any
  356  * vnode belonging to mp.
  357  *
  358  * Lookup uses vfs_busy() to traverse mount points.
  359  * root fs                      var fs
  360  * / vnode lock         A       / vnode lock (/var)             D
  361  * /var vnode lock      B       /log vnode lock(/var/log)       E
  362  * vfs_busy lock        C       vfs_busy lock                   F
  363  *
  364  * Within each file system, the lock order is C->A->B and F->D->E.
  365  *
  366  * When traversing across mounts, the system follows that lock order:
  367  *
  368  *        C->A->B
  369  *              |
  370  *              +->F->D->E
  371  *
  372  * The lookup() process for namei("/var") illustrates the process:
  373  *  VOP_LOOKUP() obtains B while A is held
  374  *  vfs_busy() obtains a shared lock on F while A and B are held
  375  *  vput() releases lock on B
  376  *  vput() releases lock on A
  377  *  VFS_ROOT() obtains lock on D while shared lock on F is held
  378  *  vfs_unbusy() releases shared lock on F
  379  *  vn_lock() obtains lock on deadfs vnode vp_crossmp instead of A.
  380  *    Attempt to lock A (instead of vp_crossmp) while D is held would
  381  *    violate the global order, causing deadlocks.
  382  *
  383  * dounmount() locks B while F is drained.
  384  */
  385 int
  386 vfs_busy(struct mount *mp, int flags)
  387 {
  388 
  389         MPASS((flags & ~MBF_MASK) == 0);
  390         CTR3(KTR_VFS, "%s: mp %p with flags %d", __func__, mp, flags);
  391 
  392         MNT_ILOCK(mp);
  393         MNT_REF(mp);
  394         /*
  395          * If mount point is currenly being unmounted, sleep until the
  396          * mount point fate is decided.  If thread doing the unmounting fails,
  397          * it will clear MNTK_UNMOUNT flag before waking us up, indicating
  398          * that this mount point has survived the unmount attempt and vfs_busy
  399          * should retry.  Otherwise the unmounter thread will set MNTK_REFEXPIRE
  400          * flag in addition to MNTK_UNMOUNT, indicating that mount point is
  401          * about to be really destroyed.  vfs_busy needs to release its
  402          * reference on the mount point in this case and return with ENOENT,
  403          * telling the caller that mount mount it tried to busy is no longer
  404          * valid.
  405          */
  406         while (mp->mnt_kern_flag & MNTK_UNMOUNT) {
  407                 if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) {
  408                         MNT_REL(mp);
  409                         MNT_IUNLOCK(mp);
  410                         CTR1(KTR_VFS, "%s: failed busying before sleeping",
  411                             __func__);
  412                         return (ENOENT);
  413                 }
  414                 if (flags & MBF_MNTLSTLOCK)
  415                         mtx_unlock(&mountlist_mtx);
  416                 mp->mnt_kern_flag |= MNTK_MWAIT;
  417                 msleep(mp, MNT_MTX(mp), PVFS | PDROP, "vfs_busy", 0);
  418                 if (flags & MBF_MNTLSTLOCK)
  419                         mtx_lock(&mountlist_mtx);
  420                 MNT_ILOCK(mp);
  421         }
  422         if (flags & MBF_MNTLSTLOCK)
  423                 mtx_unlock(&mountlist_mtx);
  424         mp->mnt_lockref++;
  425         MNT_IUNLOCK(mp);
  426         return (0);
  427 }
  428 
  429 /*
  430  * Free a busy filesystem.
  431  */
  432 void
  433 vfs_unbusy(struct mount *mp)
  434 {
  435 
  436         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  437         MNT_ILOCK(mp);
  438         MNT_REL(mp);
  439         KASSERT(mp->mnt_lockref > 0, ("negative mnt_lockref"));
  440         mp->mnt_lockref--;
  441         if (mp->mnt_lockref == 0 && (mp->mnt_kern_flag & MNTK_DRAINING) != 0) {
  442                 MPASS(mp->mnt_kern_flag & MNTK_UNMOUNT);
  443                 CTR1(KTR_VFS, "%s: waking up waiters", __func__);
  444                 mp->mnt_kern_flag &= ~MNTK_DRAINING;
  445                 wakeup(&mp->mnt_lockref);
  446         }
  447         MNT_IUNLOCK(mp);
  448 }
  449 
  450 /*
  451  * Lookup a mount point by filesystem identifier.
  452  */
  453 struct mount *
  454 vfs_getvfs(fsid_t *fsid)
  455 {
  456         struct mount *mp;
  457 
  458         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  459         mtx_lock(&mountlist_mtx);
  460         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  461                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  462                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  463                         vfs_ref(mp);
  464                         mtx_unlock(&mountlist_mtx);
  465                         return (mp);
  466                 }
  467         }
  468         mtx_unlock(&mountlist_mtx);
  469         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  470         return ((struct mount *) 0);
  471 }
  472 
  473 /*
  474  * Lookup a mount point by filesystem identifier, busying it before
  475  * returning.
  476  */
  477 struct mount *
  478 vfs_busyfs(fsid_t *fsid)
  479 {
  480         struct mount *mp;
  481         int error;
  482 
  483         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  484         mtx_lock(&mountlist_mtx);
  485         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  486                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  487                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  488                         error = vfs_busy(mp, MBF_MNTLSTLOCK);
  489                         if (error) {
  490                                 mtx_unlock(&mountlist_mtx);
  491                                 return (NULL);
  492                         }
  493                         return (mp);
  494                 }
  495         }
  496         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  497         mtx_unlock(&mountlist_mtx);
  498         return ((struct mount *) 0);
  499 }
  500 
  501 /*
  502  * Check if a user can access privileged mount options.
  503  */
  504 int
  505 vfs_suser(struct mount *mp, struct thread *td)
  506 {
  507         int error;
  508 
  509         /*
  510          * If the thread is jailed, but this is not a jail-friendly file
  511          * system, deny immediately.
  512          */
  513         if (!(mp->mnt_vfc->vfc_flags & VFCF_JAIL) && jailed(td->td_ucred))
  514                 return (EPERM);
  515 
  516         /*
  517          * If the file system was mounted outside the jail of the calling
  518          * thread, deny immediately.
  519          */
  520         if (prison_check(td->td_ucred, mp->mnt_cred) != 0)
  521                 return (EPERM);
  522 
  523         /*
  524          * If file system supports delegated administration, we don't check
  525          * for the PRIV_VFS_MOUNT_OWNER privilege - it will be better verified
  526          * by the file system itself.
  527          * If this is not the user that did original mount, we check for
  528          * the PRIV_VFS_MOUNT_OWNER privilege.
  529          */
  530         if (!(mp->mnt_vfc->vfc_flags & VFCF_DELEGADMIN) &&
  531             mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
  532                 if ((error = priv_check(td, PRIV_VFS_MOUNT_OWNER)) != 0)
  533                         return (error);
  534         }
  535         return (0);
  536 }
  537 
  538 /*
  539  * Get a new unique fsid.  Try to make its val[0] unique, since this value
  540  * will be used to create fake device numbers for stat().  Also try (but
  541  * not so hard) make its val[0] unique mod 2^16, since some emulators only
  542  * support 16-bit device numbers.  We end up with unique val[0]'s for the
  543  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
  544  *
  545  * Keep in mind that several mounts may be running in parallel.  Starting
  546  * the search one past where the previous search terminated is both a
  547  * micro-optimization and a defense against returning the same fsid to
  548  * different mounts.
  549  */
  550 void
  551 vfs_getnewfsid(struct mount *mp)
  552 {
  553         static u_int16_t mntid_base;
  554         struct mount *nmp;
  555         fsid_t tfsid;
  556         int mtype;
  557 
  558         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  559         mtx_lock(&mntid_mtx);
  560         mtype = mp->mnt_vfc->vfc_typenum;
  561         tfsid.val[1] = mtype;
  562         mtype = (mtype & 0xFF) << 24;
  563         for (;;) {
  564                 tfsid.val[0] = makedev(255,
  565                     mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
  566                 mntid_base++;
  567                 if ((nmp = vfs_getvfs(&tfsid)) == NULL)
  568                         break;
  569                 vfs_rel(nmp);
  570         }
  571         mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
  572         mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
  573         mtx_unlock(&mntid_mtx);
  574 }
  575 
  576 /*
  577  * Knob to control the precision of file timestamps:
  578  *
  579  *   0 = seconds only; nanoseconds zeroed.
  580  *   1 = seconds and nanoseconds, accurate within 1/HZ.
  581  *   2 = seconds and nanoseconds, truncated to microseconds.
  582  * >=3 = seconds and nanoseconds, maximum precision.
  583  */
  584 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
  585 
  586 static int timestamp_precision = TSP_SEC;
  587 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
  588     &timestamp_precision, 0, "File timestamp precision (0: seconds, "
  589     "1: sec + ns accurate to 1/HZ, 2: sec + ns truncated to ms, "
  590     "3+: sec + ns (max. precision))");
  591 
  592 /*
  593  * Get a current timestamp.
  594  */
  595 void
  596 vfs_timestamp(struct timespec *tsp)
  597 {
  598         struct timeval tv;
  599 
  600         switch (timestamp_precision) {
  601         case TSP_SEC:
  602                 tsp->tv_sec = time_second;
  603                 tsp->tv_nsec = 0;
  604                 break;
  605         case TSP_HZ:
  606                 getnanotime(tsp);
  607                 break;
  608         case TSP_USEC:
  609                 microtime(&tv);
  610                 TIMEVAL_TO_TIMESPEC(&tv, tsp);
  611                 break;
  612         case TSP_NSEC:
  613         default:
  614                 nanotime(tsp);
  615                 break;
  616         }
  617 }
  618 
  619 /*
  620  * Set vnode attributes to VNOVAL
  621  */
  622 void
  623 vattr_null(struct vattr *vap)
  624 {
  625 
  626         vap->va_type = VNON;
  627         vap->va_size = VNOVAL;
  628         vap->va_bytes = VNOVAL;
  629         vap->va_mode = VNOVAL;
  630         vap->va_nlink = VNOVAL;
  631         vap->va_uid = VNOVAL;
  632         vap->va_gid = VNOVAL;
  633         vap->va_fsid = VNOVAL;
  634         vap->va_fileid = VNOVAL;
  635         vap->va_blocksize = VNOVAL;
  636         vap->va_rdev = VNOVAL;
  637         vap->va_atime.tv_sec = VNOVAL;
  638         vap->va_atime.tv_nsec = VNOVAL;
  639         vap->va_mtime.tv_sec = VNOVAL;
  640         vap->va_mtime.tv_nsec = VNOVAL;
  641         vap->va_ctime.tv_sec = VNOVAL;
  642         vap->va_ctime.tv_nsec = VNOVAL;
  643         vap->va_birthtime.tv_sec = VNOVAL;
  644         vap->va_birthtime.tv_nsec = VNOVAL;
  645         vap->va_flags = VNOVAL;
  646         vap->va_gen = VNOVAL;
  647         vap->va_vaflags = 0;
  648 }
  649 
  650 /*
  651  * This routine is called when we have too many vnodes.  It attempts
  652  * to free <count> vnodes and will potentially free vnodes that still
  653  * have VM backing store (VM backing store is typically the cause
  654  * of a vnode blowout so we want to do this).  Therefore, this operation
  655  * is not considered cheap.
  656  *
  657  * A number of conditions may prevent a vnode from being reclaimed.
  658  * the buffer cache may have references on the vnode, a directory
  659  * vnode may still have references due to the namei cache representing
  660  * underlying files, or the vnode may be in active use.   It is not
  661  * desireable to reuse such vnodes.  These conditions may cause the
  662  * number of vnodes to reach some minimum value regardless of what
  663  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
  664  */
  665 static int
  666 vlrureclaim(struct mount *mp)
  667 {
  668         struct vnode *vp;
  669         int done;
  670         int trigger;
  671         int usevnodes;
  672         int count;
  673 
  674         /*
  675          * Calculate the trigger point, don't allow user
  676          * screwups to blow us up.   This prevents us from
  677          * recycling vnodes with lots of resident pages.  We
  678          * aren't trying to free memory, we are trying to
  679          * free vnodes.
  680          */
  681         usevnodes = desiredvnodes;
  682         if (usevnodes <= 0)
  683                 usevnodes = 1;
  684         trigger = cnt.v_page_count * 2 / usevnodes;
  685         done = 0;
  686         vn_start_write(NULL, &mp, V_WAIT);
  687         MNT_ILOCK(mp);
  688         count = mp->mnt_nvnodelistsize / 10 + 1;
  689         while (count != 0) {
  690                 vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
  691                 while (vp != NULL && vp->v_type == VMARKER)
  692                         vp = TAILQ_NEXT(vp, v_nmntvnodes);
  693                 if (vp == NULL)
  694                         break;
  695                 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  696                 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  697                 --count;
  698                 if (!VI_TRYLOCK(vp))
  699                         goto next_iter;
  700                 /*
  701                  * If it's been deconstructed already, it's still
  702                  * referenced, or it exceeds the trigger, skip it.
  703                  */
  704                 if (vp->v_usecount ||
  705                     (!vlru_allow_cache_src &&
  706                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  707                     (vp->v_iflag & VI_DOOMED) != 0 || (vp->v_object != NULL &&
  708                     vp->v_object->resident_page_count > trigger)) {
  709                         VI_UNLOCK(vp);
  710                         goto next_iter;
  711                 }
  712                 MNT_IUNLOCK(mp);
  713                 vholdl(vp);
  714                 if (VOP_LOCK(vp, LK_INTERLOCK|LK_EXCLUSIVE|LK_NOWAIT)) {
  715                         vdrop(vp);
  716                         goto next_iter_mntunlocked;
  717                 }
  718                 VI_LOCK(vp);
  719                 /*
  720                  * v_usecount may have been bumped after VOP_LOCK() dropped
  721                  * the vnode interlock and before it was locked again.
  722                  *
  723                  * It is not necessary to recheck VI_DOOMED because it can
  724                  * only be set by another thread that holds both the vnode
  725                  * lock and vnode interlock.  If another thread has the
  726                  * vnode lock before we get to VOP_LOCK() and obtains the
  727                  * vnode interlock after VOP_LOCK() drops the vnode
  728                  * interlock, the other thread will be unable to drop the
  729                  * vnode lock before our VOP_LOCK() call fails.
  730                  */
  731                 if (vp->v_usecount ||
  732                     (!vlru_allow_cache_src &&
  733                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  734                     (vp->v_object != NULL &&
  735                     vp->v_object->resident_page_count > trigger)) {
  736                         VOP_UNLOCK(vp, LK_INTERLOCK);
  737                         goto next_iter_mntunlocked;
  738                 }
  739                 KASSERT((vp->v_iflag & VI_DOOMED) == 0,
  740                     ("VI_DOOMED unexpectedly detected in vlrureclaim()"));
  741                 vgonel(vp);
  742                 VOP_UNLOCK(vp, 0);
  743                 vdropl(vp);
  744                 done++;
  745 next_iter_mntunlocked:
  746                 if ((count % 256) != 0)
  747                         goto relock_mnt;
  748                 goto yield;
  749 next_iter:
  750                 if ((count % 256) != 0)
  751                         continue;
  752                 MNT_IUNLOCK(mp);
  753 yield:
  754                 uio_yield();
  755 relock_mnt:
  756                 MNT_ILOCK(mp);
  757         }
  758         MNT_IUNLOCK(mp);
  759         vn_finished_write(mp);
  760         return done;
  761 }
  762 
  763 /*
  764  * Attempt to keep the free list at wantfreevnodes length.
  765  */
  766 static void
  767 vnlru_free(int count)
  768 {
  769         struct vnode *vp;
  770         int vfslocked;
  771 
  772         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
  773         for (; count > 0; count--) {
  774                 vp = TAILQ_FIRST(&vnode_free_list);
  775                 /*
  776                  * The list can be modified while the free_list_mtx
  777                  * has been dropped and vp could be NULL here.
  778                  */
  779                 if (!vp)
  780                         break;
  781                 VNASSERT(vp->v_op != NULL, vp,
  782                     ("vnlru_free: vnode already reclaimed."));
  783                 TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
  784                 /*
  785                  * Don't recycle if we can't get the interlock.
  786                  */
  787                 if (!VI_TRYLOCK(vp)) {
  788                         TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
  789                         continue;
  790                 }
  791                 VNASSERT(VCANRECYCLE(vp), vp,
  792                     ("vp inconsistent on freelist"));
  793                 freevnodes--;
  794                 vp->v_iflag &= ~VI_FREE;
  795                 vholdl(vp);
  796                 mtx_unlock(&vnode_free_list_mtx);
  797                 VI_UNLOCK(vp);
  798                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  799                 vtryrecycle(vp);
  800                 VFS_UNLOCK_GIANT(vfslocked);
  801                 /*
  802                  * If the recycled succeeded this vdrop will actually free
  803                  * the vnode.  If not it will simply place it back on
  804                  * the free list.
  805                  */
  806                 vdrop(vp);
  807                 mtx_lock(&vnode_free_list_mtx);
  808         }
  809 }
  810 /*
  811  * Attempt to recycle vnodes in a context that is always safe to block.
  812  * Calling vlrurecycle() from the bowels of filesystem code has some
  813  * interesting deadlock problems.
  814  */
  815 static struct proc *vnlruproc;
  816 static int vnlruproc_sig;
  817 
  818 static void
  819 vnlru_proc(void)
  820 {
  821         struct mount *mp, *nmp;
  822         int done, vfslocked;
  823         struct proc *p = vnlruproc;
  824 
  825         EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
  826             SHUTDOWN_PRI_FIRST);
  827 
  828         for (;;) {
  829                 kproc_suspend_check(p);
  830                 mtx_lock(&vnode_free_list_mtx);
  831                 if (freevnodes > wantfreevnodes)
  832                         vnlru_free(freevnodes - wantfreevnodes);
  833                 if (numvnodes <= desiredvnodes * 9 / 10) {
  834                         vnlruproc_sig = 0;
  835                         wakeup(&vnlruproc_sig);
  836                         msleep(vnlruproc, &vnode_free_list_mtx,
  837                             PVFS|PDROP, "vlruwt", hz);
  838                         continue;
  839                 }
  840                 mtx_unlock(&vnode_free_list_mtx);
  841                 done = 0;
  842                 mtx_lock(&mountlist_mtx);
  843                 for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
  844                         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
  845                                 nmp = TAILQ_NEXT(mp, mnt_list);
  846                                 continue;
  847                         }
  848                         vfslocked = VFS_LOCK_GIANT(mp);
  849                         done += vlrureclaim(mp);
  850                         VFS_UNLOCK_GIANT(vfslocked);
  851                         mtx_lock(&mountlist_mtx);
  852                         nmp = TAILQ_NEXT(mp, mnt_list);
  853                         vfs_unbusy(mp);
  854                 }
  855                 mtx_unlock(&mountlist_mtx);
  856                 if (done == 0) {
  857 #if 0
  858                         /* These messages are temporary debugging aids */
  859                         if (vnlru_nowhere < 5)
  860                                 printf("vnlru process getting nowhere..\n");
  861                         else if (vnlru_nowhere == 5)
  862                                 printf("vnlru process messages stopped.\n");
  863 #endif
  864                         vnlru_nowhere++;
  865                         tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
  866                 } else
  867                         uio_yield();
  868         }
  869 }
  870 
  871 static struct kproc_desc vnlru_kp = {
  872         "vnlru",
  873         vnlru_proc,
  874         &vnlruproc
  875 };
  876 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start,
  877     &vnlru_kp);
  878  
  879 /*
  880  * Routines having to do with the management of the vnode table.
  881  */
  882 
  883 void
  884 vdestroy(struct vnode *vp)
  885 {
  886         struct bufobj *bo;
  887 
  888         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  889         mtx_lock(&vnode_free_list_mtx);
  890         numvnodes--;
  891         mtx_unlock(&vnode_free_list_mtx);
  892         bo = &vp->v_bufobj;
  893         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
  894             ("cleaned vnode still on the free list."));
  895         VNASSERT(vp->v_data == NULL, vp, ("cleaned vnode isn't"));
  896         VNASSERT(vp->v_holdcnt == 0, vp, ("Non-zero hold count"));
  897         VNASSERT(vp->v_usecount == 0, vp, ("Non-zero use count"));
  898         VNASSERT(vp->v_writecount == 0, vp, ("Non-zero write count"));
  899         VNASSERT(bo->bo_numoutput == 0, vp, ("Clean vnode has pending I/O's"));
  900         VNASSERT(bo->bo_clean.bv_cnt == 0, vp, ("cleanbufcnt not 0"));
  901         VNASSERT(bo->bo_clean.bv_root == NULL, vp, ("cleanblkroot not NULL"));
  902         VNASSERT(bo->bo_dirty.bv_cnt == 0, vp, ("dirtybufcnt not 0"));
  903         VNASSERT(bo->bo_dirty.bv_root == NULL, vp, ("dirtyblkroot not NULL"));
  904         VNASSERT(TAILQ_EMPTY(&vp->v_cache_dst), vp, ("vp has namecache dst"));
  905         VNASSERT(LIST_EMPTY(&vp->v_cache_src), vp, ("vp has namecache src"));
  906         VNASSERT(vp->v_cache_dd == NULL, vp, ("vp has namecache for .."));
  907         VI_UNLOCK(vp);
  908 #ifdef MAC
  909         mac_vnode_destroy(vp);
  910 #endif
  911         if (vp->v_pollinfo != NULL)
  912                 destroy_vpollinfo(vp->v_pollinfo);
  913 #ifdef INVARIANTS
  914         /* XXX Elsewhere we can detect an already freed vnode via NULL v_op. */
  915         vp->v_op = NULL;
  916 #endif
  917         lockdestroy(vp->v_vnlock);
  918         mtx_destroy(&vp->v_interlock);
  919         mtx_destroy(BO_MTX(bo));
  920         uma_zfree(vnode_zone, vp);
  921 }
  922 
  923 /*
  924  * Try to recycle a freed vnode.  We abort if anyone picks up a reference
  925  * before we actually vgone().  This function must be called with the vnode
  926  * held to prevent the vnode from being returned to the free list midway
  927  * through vgone().
  928  */
  929 static int
  930 vtryrecycle(struct vnode *vp)
  931 {
  932         struct mount *vnmp;
  933 
  934         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  935         VNASSERT(vp->v_holdcnt, vp,
  936             ("vtryrecycle: Recycling vp %p without a reference.", vp));
  937         /*
  938          * This vnode may found and locked via some other list, if so we
  939          * can't recycle it yet.
  940          */
  941         if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
  942                 CTR2(KTR_VFS,
  943                     "%s: impossible to recycle, vp %p lock is already held",
  944                     __func__, vp);
  945                 return (EWOULDBLOCK);
  946         }
  947         /*
  948          * Don't recycle if its filesystem is being suspended.
  949          */
  950         if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
  951                 VOP_UNLOCK(vp, 0);
  952                 CTR2(KTR_VFS,
  953                     "%s: impossible to recycle, cannot start the write for %p",
  954                     __func__, vp);
  955                 return (EBUSY);
  956         }
  957         /*
  958          * If we got this far, we need to acquire the interlock and see if
  959          * anyone picked up this vnode from another list.  If not, we will
  960          * mark it with DOOMED via vgonel() so that anyone who does find it
  961          * will skip over it.
  962          */
  963         VI_LOCK(vp);
  964         if (vp->v_usecount) {
  965                 VOP_UNLOCK(vp, LK_INTERLOCK);
  966                 vn_finished_write(vnmp);
  967                 CTR2(KTR_VFS,
  968                     "%s: impossible to recycle, %p is already referenced",
  969                     __func__, vp);
  970                 return (EBUSY);
  971         }
  972         if ((vp->v_iflag & VI_DOOMED) == 0)
  973                 vgonel(vp);
  974         VOP_UNLOCK(vp, LK_INTERLOCK);
  975         vn_finished_write(vnmp);
  976         return (0);
  977 }
  978 
  979 /*
  980  * Wait for available vnodes.
  981  */
  982 static int
  983 getnewvnode_wait(int suspended)
  984 {
  985 
  986         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
  987         if (numvnodes > desiredvnodes) {
  988                 if (suspended) {
  989                         /*
  990                          * File system is beeing suspended, we cannot risk a
  991                          * deadlock here, so allocate new vnode anyway.
  992                          */
  993                         if (freevnodes > wantfreevnodes)
  994                                 vnlru_free(freevnodes - wantfreevnodes);
  995                         return (0);
  996                 }
  997                 if (vnlruproc_sig == 0) {
  998                         vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
  999                         wakeup(vnlruproc);
 1000                 }
 1001                 msleep(&vnlruproc_sig, &vnode_free_list_mtx, PVFS,
 1002                     "vlruwk", hz);
 1003         }
 1004         return (numvnodes > desiredvnodes ? ENFILE : 0);
 1005 }
 1006 
 1007 void
 1008 getnewvnode_reserve(u_int count)
 1009 {
 1010         struct thread *td;
 1011 
 1012         td = curthread;
 1013         mtx_lock(&vnode_free_list_mtx);
 1014         while (count > 0) {
 1015                 if (getnewvnode_wait(0) == 0) {
 1016                         count--;
 1017                         td->td_vp_reserv++;
 1018                         numvnodes++;
 1019                 }
 1020         }
 1021         mtx_unlock(&vnode_free_list_mtx);
 1022 }
 1023 
 1024 void
 1025 getnewvnode_drop_reserve(void)
 1026 {
 1027         struct thread *td;
 1028 
 1029         td = curthread;
 1030         mtx_lock(&vnode_free_list_mtx);
 1031         KASSERT(numvnodes >= td->td_vp_reserv, ("reserve too large"));
 1032         numvnodes -= td->td_vp_reserv;
 1033         mtx_unlock(&vnode_free_list_mtx);
 1034         td->td_vp_reserv = 0;
 1035 }
 1036 
 1037 /*
 1038  * Return the next vnode from the free list.
 1039  */
 1040 int
 1041 getnewvnode(const char *tag, struct mount *mp, struct vop_vector *vops,
 1042     struct vnode **vpp)
 1043 {
 1044         struct vnode *vp;
 1045         struct bufobj *bo;
 1046         struct thread *td;
 1047         int error;
 1048 
 1049         CTR3(KTR_VFS, "%s: mp %p with tag %s", __func__, mp, tag);
 1050         vp = NULL;
 1051         td = curthread;
 1052         if (td->td_vp_reserv > 0) {
 1053                 td->td_vp_reserv -= 1;
 1054                 goto alloc;
 1055         }
 1056         mtx_lock(&vnode_free_list_mtx);
 1057         /*
 1058          * Lend our context to reclaim vnodes if they've exceeded the max.
 1059          */
 1060         if (freevnodes > wantfreevnodes)
 1061                 vnlru_free(1);
 1062         error = getnewvnode_wait(mp != NULL && (mp->mnt_kern_flag &
 1063             MNTK_SUSPEND));
 1064 #if 0   /* XXX Not all VFS_VGET/ffs_vget callers check returns. */
 1065         if (error != 0) {
 1066                 mtx_unlock(&vnode_free_list_mtx);
 1067                 return (error);
 1068         }
 1069 #endif
 1070         numvnodes++;
 1071         mtx_unlock(&vnode_free_list_mtx);
 1072 alloc:
 1073         vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
 1074         /*
 1075          * Setup locks.
 1076          */
 1077         vp->v_vnlock = &vp->v_lock;
 1078         mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
 1079         /*
 1080          * By default, don't allow shared locks unless filesystems
 1081          * opt-in.
 1082          */
 1083         lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOSHARE);
 1084         /*
 1085          * Initialize bufobj.
 1086          */
 1087         bo = &vp->v_bufobj;
 1088         bo->__bo_vnode = vp;
 1089         mtx_init(BO_MTX(bo), "bufobj interlock", NULL, MTX_DEF);
 1090         bo->bo_ops = &buf_ops_bio;
 1091         bo->bo_private = vp;
 1092         TAILQ_INIT(&bo->bo_clean.bv_hd);
 1093         TAILQ_INIT(&bo->bo_dirty.bv_hd);
 1094         /*
 1095          * Initialize namecache.
 1096          */
 1097         LIST_INIT(&vp->v_cache_src);
 1098         TAILQ_INIT(&vp->v_cache_dst);
 1099         /*
 1100          * Finalize various vnode identity bits.
 1101          */
 1102         vp->v_type = VNON;
 1103         vp->v_tag = tag;
 1104         vp->v_op = vops;
 1105         v_incr_usecount(vp);
 1106         vp->v_data = 0;
 1107 #ifdef MAC
 1108         mac_vnode_init(vp);
 1109         if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
 1110                 mac_vnode_associate_singlelabel(mp, vp);
 1111         else if (mp == NULL && vops != &dead_vnodeops)
 1112                 printf("NULL mp in getnewvnode()\n");
 1113 #endif
 1114         if (mp != NULL) {
 1115                 bo->bo_bsize = mp->mnt_stat.f_iosize;
 1116                 if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
 1117                         vp->v_vflag |= VV_NOKNOTE;
 1118         }
 1119 
 1120         *vpp = vp;
 1121         return (0);
 1122 }
 1123 
 1124 /*
 1125  * Delete from old mount point vnode list, if on one.
 1126  */
 1127 static void
 1128 delmntque(struct vnode *vp)
 1129 {
 1130         struct mount *mp;
 1131 
 1132         mp = vp->v_mount;
 1133         if (mp == NULL)
 1134                 return;
 1135         MNT_ILOCK(mp);
 1136         vp->v_mount = NULL;
 1137         VNASSERT(mp->mnt_nvnodelistsize > 0, vp,
 1138                 ("bad mount point vnode list size"));
 1139         TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1140         mp->mnt_nvnodelistsize--;
 1141         MNT_REL(mp);
 1142         MNT_IUNLOCK(mp);
 1143 }
 1144 
 1145 static void
 1146 insmntque_stddtr(struct vnode *vp, void *dtr_arg)
 1147 {
 1148 
 1149         vp->v_data = NULL;
 1150         vp->v_op = &dead_vnodeops;
 1151         /* XXX non mp-safe fs may still call insmntque with vnode
 1152            unlocked */
 1153         if (!VOP_ISLOCKED(vp))
 1154                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1155         vgone(vp);
 1156         vput(vp);
 1157 }
 1158 
 1159 /*
 1160  * Insert into list of vnodes for the new mount point, if available.
 1161  */
 1162 int
 1163 insmntque1(struct vnode *vp, struct mount *mp,
 1164         void (*dtr)(struct vnode *, void *), void *dtr_arg)
 1165 {
 1166         int locked;
 1167 
 1168         KASSERT(vp->v_mount == NULL,
 1169                 ("insmntque: vnode already on per mount vnode list"));
 1170         VNASSERT(mp != NULL, vp, ("Don't call insmntque(foo, NULL)"));
 1171 #ifdef DEBUG_VFS_LOCKS
 1172         if (!VFS_NEEDSGIANT(mp))
 1173                 ASSERT_VOP_ELOCKED(vp,
 1174                     "insmntque: mp-safe fs and non-locked vp");
 1175 #endif
 1176         MNT_ILOCK(mp);
 1177         if ((mp->mnt_kern_flag & MNTK_NOINSMNTQ) != 0 &&
 1178             ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0 ||
 1179              mp->mnt_nvnodelistsize == 0)) {
 1180                 locked = VOP_ISLOCKED(vp);
 1181                 if (!locked || (locked == LK_EXCLUSIVE &&
 1182                      (vp->v_vflag & VV_FORCEINSMQ) == 0)) {
 1183                         MNT_IUNLOCK(mp);
 1184                         if (dtr != NULL)
 1185                                 dtr(vp, dtr_arg);
 1186                         return (EBUSY);
 1187                 }
 1188         }
 1189         vp->v_mount = mp;
 1190         MNT_REF(mp);
 1191         TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1192         VNASSERT(mp->mnt_nvnodelistsize >= 0, vp,
 1193                 ("neg mount point vnode list size"));
 1194         mp->mnt_nvnodelistsize++;
 1195         MNT_IUNLOCK(mp);
 1196         return (0);
 1197 }
 1198 
 1199 int
 1200 insmntque(struct vnode *vp, struct mount *mp)
 1201 {
 1202 
 1203         return (insmntque1(vp, mp, insmntque_stddtr, NULL));
 1204 }
 1205 
 1206 /*
 1207  * Flush out and invalidate all buffers associated with a bufobj
 1208  * Called with the underlying object locked.
 1209  */
 1210 int
 1211 bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo)
 1212 {
 1213         int error;
 1214 
 1215         BO_LOCK(bo);
 1216         if (flags & V_SAVE) {
 1217                 error = bufobj_wwait(bo, slpflag, slptimeo);
 1218                 if (error) {
 1219                         BO_UNLOCK(bo);
 1220                         return (error);
 1221                 }
 1222                 if (bo->bo_dirty.bv_cnt > 0) {
 1223                         BO_UNLOCK(bo);
 1224                         if ((error = BO_SYNC(bo, MNT_WAIT)) != 0)
 1225                                 return (error);
 1226                         /*
 1227                          * XXX We could save a lock/unlock if this was only
 1228                          * enabled under INVARIANTS
 1229                          */
 1230                         BO_LOCK(bo);
 1231                         if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
 1232                                 panic("vinvalbuf: dirty bufs");
 1233                 }
 1234         }
 1235         /*
 1236          * If you alter this loop please notice that interlock is dropped and
 1237          * reacquired in flushbuflist.  Special care is needed to ensure that
 1238          * no race conditions occur from this.
 1239          */
 1240         do {
 1241                 error = flushbuflist(&bo->bo_clean,
 1242                     flags, bo, slpflag, slptimeo);
 1243                 if (error == 0 && !(flags & V_CLEANONLY))
 1244                         error = flushbuflist(&bo->bo_dirty,
 1245                             flags, bo, slpflag, slptimeo);
 1246                 if (error != 0 && error != EAGAIN) {
 1247                         BO_UNLOCK(bo);
 1248                         return (error);
 1249                 }
 1250         } while (error != 0);
 1251 
 1252         /*
 1253          * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
 1254          * have write I/O in-progress but if there is a VM object then the
 1255          * VM object can also have read-I/O in-progress.
 1256          */
 1257         do {
 1258                 bufobj_wwait(bo, 0, 0);
 1259                 BO_UNLOCK(bo);
 1260                 if (bo->bo_object != NULL) {
 1261                         VM_OBJECT_LOCK(bo->bo_object);
 1262                         vm_object_pip_wait(bo->bo_object, "bovlbx");
 1263                         VM_OBJECT_UNLOCK(bo->bo_object);
 1264                 }
 1265                 BO_LOCK(bo);
 1266         } while (bo->bo_numoutput > 0);
 1267         BO_UNLOCK(bo);
 1268 
 1269         /*
 1270          * Destroy the copy in the VM cache, too.
 1271          */
 1272         if (bo->bo_object != NULL &&
 1273             (flags & (V_ALT | V_NORMAL | V_CLEANONLY)) == 0) {
 1274                 VM_OBJECT_LOCK(bo->bo_object);
 1275                 vm_object_page_remove(bo->bo_object, 0, 0,
 1276                         (flags & V_SAVE) ? TRUE : FALSE);
 1277                 VM_OBJECT_UNLOCK(bo->bo_object);
 1278         }
 1279 
 1280 #ifdef INVARIANTS
 1281         BO_LOCK(bo);
 1282         if ((flags & (V_ALT | V_NORMAL | V_CLEANONLY)) == 0 &&
 1283             (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
 1284                 panic("vinvalbuf: flush failed");
 1285         BO_UNLOCK(bo);
 1286 #endif
 1287         return (0);
 1288 }
 1289 
 1290 /*
 1291  * Flush out and invalidate all buffers associated with a vnode.
 1292  * Called with the underlying object locked.
 1293  */
 1294 int
 1295 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
 1296 {
 1297 
 1298         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 1299         ASSERT_VOP_LOCKED(vp, "vinvalbuf");
 1300         return (bufobj_invalbuf(&vp->v_bufobj, flags, slpflag, slptimeo));
 1301 }
 1302 
 1303 /*
 1304  * Flush out buffers on the specified list.
 1305  *
 1306  */
 1307 static int
 1308 flushbuflist( struct bufv *bufv, int flags, struct bufobj *bo, int slpflag,
 1309     int slptimeo)
 1310 {
 1311         struct buf *bp, *nbp;
 1312         int retval, error;
 1313         daddr_t lblkno;
 1314         b_xflags_t xflags;
 1315 
 1316         ASSERT_BO_LOCKED(bo);
 1317 
 1318         retval = 0;
 1319         TAILQ_FOREACH_SAFE(bp, &bufv->bv_hd, b_bobufs, nbp) {
 1320                 if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
 1321                     ((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
 1322                         continue;
 1323                 }
 1324                 lblkno = 0;
 1325                 xflags = 0;
 1326                 if (nbp != NULL) {
 1327                         lblkno = nbp->b_lblkno;
 1328                         xflags = nbp->b_xflags &
 1329                                 (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN);
 1330                 }
 1331                 retval = EAGAIN;
 1332                 error = BUF_TIMELOCK(bp,
 1333                     LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, BO_MTX(bo),
 1334                     "flushbuf", slpflag, slptimeo);
 1335                 if (error) {
 1336                         BO_LOCK(bo);
 1337                         return (error != ENOLCK ? error : EAGAIN);
 1338                 }
 1339                 KASSERT(bp->b_bufobj == bo,
 1340                     ("bp %p wrong b_bufobj %p should be %p",
 1341                     bp, bp->b_bufobj, bo));
 1342                 if (bp->b_bufobj != bo) {       /* XXX: necessary ? */
 1343                         BUF_UNLOCK(bp);
 1344                         BO_LOCK(bo);
 1345                         return (EAGAIN);
 1346                 }
 1347                 /*
 1348                  * XXX Since there are no node locks for NFS, I
 1349                  * believe there is a slight chance that a delayed
 1350                  * write will occur while sleeping just above, so
 1351                  * check for it.
 1352                  */
 1353                 if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
 1354                     (flags & V_SAVE)) {
 1355                         BO_LOCK(bo);
 1356                         bremfree(bp);
 1357                         BO_UNLOCK(bo);
 1358                         bp->b_flags |= B_ASYNC;
 1359                         bwrite(bp);
 1360                         BO_LOCK(bo);
 1361                         return (EAGAIN);        /* XXX: why not loop ? */
 1362                 }
 1363                 BO_LOCK(bo);
 1364                 bremfree(bp);
 1365                 BO_UNLOCK(bo);
 1366                 bp->b_flags |= (B_INVAL | B_RELBUF);
 1367                 bp->b_flags &= ~B_ASYNC;
 1368                 brelse(bp);
 1369                 BO_LOCK(bo);
 1370                 if (nbp != NULL &&
 1371                     (nbp->b_bufobj != bo ||
 1372                      nbp->b_lblkno != lblkno ||
 1373                      (nbp->b_xflags &
 1374                       (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN)) != xflags))
 1375                         break;                  /* nbp invalid */
 1376         }
 1377         return (retval);
 1378 }
 1379 
 1380 /*
 1381  * Truncate a file's buffer and pages to a specified length.  This
 1382  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
 1383  * sync activity.
 1384  */
 1385 int
 1386 vtruncbuf(struct vnode *vp, struct ucred *cred, struct thread *td,
 1387     off_t length, int blksize)
 1388 {
 1389         struct buf *bp, *nbp;
 1390         int anyfreed;
 1391         int trunclbn;
 1392         struct bufobj *bo;
 1393 
 1394         CTR5(KTR_VFS, "%s: vp %p with cred %p and block %d:%ju", __func__,
 1395             vp, cred, blksize, (uintmax_t)length);
 1396 
 1397         /*
 1398          * Round up to the *next* lbn.
 1399          */
 1400         trunclbn = (length + blksize - 1) / blksize;
 1401 
 1402         ASSERT_VOP_LOCKED(vp, "vtruncbuf");
 1403 restart:
 1404         bo = &vp->v_bufobj;
 1405         BO_LOCK(bo);
 1406         anyfreed = 1;
 1407         for (;anyfreed;) {
 1408                 anyfreed = 0;
 1409                 TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
 1410                         if (bp->b_lblkno < trunclbn)
 1411                                 continue;
 1412                         if (BUF_LOCK(bp,
 1413                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1414                             BO_MTX(bo)) == ENOLCK)
 1415                                 goto restart;
 1416 
 1417                         BO_LOCK(bo);
 1418                         bremfree(bp);
 1419                         BO_UNLOCK(bo);
 1420                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1421                         bp->b_flags &= ~B_ASYNC;
 1422                         brelse(bp);
 1423                         anyfreed = 1;
 1424 
 1425                         BO_LOCK(bo);
 1426                         if (nbp != NULL &&
 1427                             (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
 1428                             (nbp->b_vp != vp) ||
 1429                             (nbp->b_flags & B_DELWRI))) {
 1430                                 BO_UNLOCK(bo);
 1431                                 goto restart;
 1432                         }
 1433                 }
 1434 
 1435                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1436                         if (bp->b_lblkno < trunclbn)
 1437                                 continue;
 1438                         if (BUF_LOCK(bp,
 1439                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1440                             BO_MTX(bo)) == ENOLCK)
 1441                                 goto restart;
 1442                         BO_LOCK(bo);
 1443                         bremfree(bp);
 1444                         BO_UNLOCK(bo);
 1445                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1446                         bp->b_flags &= ~B_ASYNC;
 1447                         brelse(bp);
 1448                         anyfreed = 1;
 1449 
 1450                         BO_LOCK(bo);
 1451                         if (nbp != NULL &&
 1452                             (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
 1453                             (nbp->b_vp != vp) ||
 1454                             (nbp->b_flags & B_DELWRI) == 0)) {
 1455                                 BO_UNLOCK(bo);
 1456                                 goto restart;
 1457                         }
 1458                 }
 1459         }
 1460 
 1461         if (length > 0) {
 1462 restartsync:
 1463                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1464                         if (bp->b_lblkno > 0)
 1465                                 continue;
 1466                         /*
 1467                          * Since we hold the vnode lock this should only
 1468                          * fail if we're racing with the buf daemon.
 1469                          */
 1470                         if (BUF_LOCK(bp,
 1471                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1472                             BO_MTX(bo)) == ENOLCK) {
 1473                                 goto restart;
 1474                         }
 1475                         VNASSERT((bp->b_flags & B_DELWRI), vp,
 1476                             ("buf(%p) on dirty queue without DELWRI", bp));
 1477 
 1478                         BO_LOCK(bo);
 1479                         bremfree(bp);
 1480                         BO_UNLOCK(bo);
 1481                         bawrite(bp);
 1482                         BO_LOCK(bo);
 1483                         goto restartsync;
 1484                 }
 1485         }
 1486 
 1487         bufobj_wwait(bo, 0, 0);
 1488         BO_UNLOCK(bo);
 1489         vnode_pager_setsize(vp, length);
 1490 
 1491         return (0);
 1492 }
 1493 
 1494 /*
 1495  * buf_splay() - splay tree core for the clean/dirty list of buffers in
 1496  *               a vnode.
 1497  *
 1498  *      NOTE: We have to deal with the special case of a background bitmap
 1499  *      buffer, a situation where two buffers will have the same logical
 1500  *      block offset.  We want (1) only the foreground buffer to be accessed
 1501  *      in a lookup and (2) must differentiate between the foreground and
 1502  *      background buffer in the splay tree algorithm because the splay
 1503  *      tree cannot normally handle multiple entities with the same 'index'.
 1504  *      We accomplish this by adding differentiating flags to the splay tree's
 1505  *      numerical domain.
 1506  */
 1507 static
 1508 struct buf *
 1509 buf_splay(daddr_t lblkno, b_xflags_t xflags, struct buf *root)
 1510 {
 1511         struct buf dummy;
 1512         struct buf *lefttreemax, *righttreemin, *y;
 1513 
 1514         if (root == NULL)
 1515                 return (NULL);
 1516         lefttreemax = righttreemin = &dummy;
 1517         for (;;) {
 1518                 if (lblkno < root->b_lblkno ||
 1519                     (lblkno == root->b_lblkno &&
 1520                     (xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1521                         if ((y = root->b_left) == NULL)
 1522                                 break;
 1523                         if (lblkno < y->b_lblkno) {
 1524                                 /* Rotate right. */
 1525                                 root->b_left = y->b_right;
 1526                                 y->b_right = root;
 1527                                 root = y;
 1528                                 if ((y = root->b_left) == NULL)
 1529                                         break;
 1530                         }
 1531                         /* Link into the new root's right tree. */
 1532                         righttreemin->b_left = root;
 1533                         righttreemin = root;
 1534                 } else if (lblkno > root->b_lblkno ||
 1535                     (lblkno == root->b_lblkno &&
 1536                     (xflags & BX_BKGRDMARKER) > (root->b_xflags & BX_BKGRDMARKER))) {
 1537                         if ((y = root->b_right) == NULL)
 1538                                 break;
 1539                         if (lblkno > y->b_lblkno) {
 1540                                 /* Rotate left. */
 1541                                 root->b_right = y->b_left;
 1542                                 y->b_left = root;
 1543                                 root = y;
 1544                                 if ((y = root->b_right) == NULL)
 1545                                         break;
 1546                         }
 1547                         /* Link into the new root's left tree. */
 1548                         lefttreemax->b_right = root;
 1549                         lefttreemax = root;
 1550                 } else {
 1551                         break;
 1552                 }
 1553                 root = y;
 1554         }
 1555         /* Assemble the new root. */
 1556         lefttreemax->b_right = root->b_left;
 1557         righttreemin->b_left = root->b_right;
 1558         root->b_left = dummy.b_right;
 1559         root->b_right = dummy.b_left;
 1560         return (root);
 1561 }
 1562 
 1563 static void
 1564 buf_vlist_remove(struct buf *bp)
 1565 {
 1566         struct buf *root;
 1567         struct bufv *bv;
 1568 
 1569         KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
 1570         ASSERT_BO_LOCKED(bp->b_bufobj);
 1571         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) !=
 1572             (BX_VNDIRTY|BX_VNCLEAN),
 1573             ("buf_vlist_remove: Buf %p is on two lists", bp));
 1574         if (bp->b_xflags & BX_VNDIRTY)
 1575                 bv = &bp->b_bufobj->bo_dirty;
 1576         else
 1577                 bv = &bp->b_bufobj->bo_clean;
 1578         if (bp != bv->bv_root) {
 1579                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1580                 KASSERT(root == bp, ("splay lookup failed in remove"));
 1581         }
 1582         if (bp->b_left == NULL) {
 1583                 root = bp->b_right;
 1584         } else {
 1585                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
 1586                 root->b_right = bp->b_right;
 1587         }
 1588         bv->bv_root = root;
 1589         TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
 1590         bv->bv_cnt--;
 1591         bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
 1592 }
 1593 
 1594 /*
 1595  * Add the buffer to the sorted clean or dirty block list using a
 1596  * splay tree algorithm.
 1597  *
 1598  * NOTE: xflags is passed as a constant, optimizing this inline function!
 1599  */
 1600 static void
 1601 buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
 1602 {
 1603         struct buf *root;
 1604         struct bufv *bv;
 1605 
 1606         ASSERT_BO_LOCKED(bo);
 1607         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
 1608             ("buf_vlist_add: Buf %p has existing xflags %d", bp, bp->b_xflags));
 1609         bp->b_xflags |= xflags;
 1610         if (xflags & BX_VNDIRTY)
 1611                 bv = &bo->bo_dirty;
 1612         else
 1613                 bv = &bo->bo_clean;
 1614 
 1615         root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1616         if (root == NULL) {
 1617                 bp->b_left = NULL;
 1618                 bp->b_right = NULL;
 1619                 TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
 1620         } else if (bp->b_lblkno < root->b_lblkno ||
 1621             (bp->b_lblkno == root->b_lblkno &&
 1622             (bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1623                 bp->b_left = root->b_left;
 1624                 bp->b_right = root;
 1625                 root->b_left = NULL;
 1626                 TAILQ_INSERT_BEFORE(root, bp, b_bobufs);
 1627         } else {
 1628                 bp->b_right = root->b_right;
 1629                 bp->b_left = root;
 1630                 root->b_right = NULL;
 1631                 TAILQ_INSERT_AFTER(&bv->bv_hd, root, bp, b_bobufs);
 1632         }
 1633         bv->bv_cnt++;
 1634         bv->bv_root = bp;
 1635 }
 1636 
 1637 /*
 1638  * Lookup a buffer using the splay tree.  Note that we specifically avoid
 1639  * shadow buffers used in background bitmap writes.
 1640  *
 1641  * This code isn't quite efficient as it could be because we are maintaining
 1642  * two sorted lists and do not know which list the block resides in.
 1643  *
 1644  * During a "make buildworld" the desired buffer is found at one of
 1645  * the roots more than 60% of the time.  Thus, checking both roots
 1646  * before performing either splay eliminates unnecessary splays on the
 1647  * first tree splayed.
 1648  */
 1649 struct buf *
 1650 gbincore(struct bufobj *bo, daddr_t lblkno)
 1651 {
 1652         struct buf *bp;
 1653 
 1654         ASSERT_BO_LOCKED(bo);
 1655         if ((bp = bo->bo_clean.bv_root) != NULL &&
 1656             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1657                 return (bp);
 1658         if ((bp = bo->bo_dirty.bv_root) != NULL &&
 1659             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1660                 return (bp);
 1661         if ((bp = bo->bo_clean.bv_root) != NULL) {
 1662                 bo->bo_clean.bv_root = bp = buf_splay(lblkno, 0, bp);
 1663                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1664                         return (bp);
 1665         }
 1666         if ((bp = bo->bo_dirty.bv_root) != NULL) {
 1667                 bo->bo_dirty.bv_root = bp = buf_splay(lblkno, 0, bp);
 1668                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1669                         return (bp);
 1670         }
 1671         return (NULL);
 1672 }
 1673 
 1674 /*
 1675  * Associate a buffer with a vnode.
 1676  */
 1677 void
 1678 bgetvp(struct vnode *vp, struct buf *bp)
 1679 {
 1680         struct bufobj *bo;
 1681 
 1682         bo = &vp->v_bufobj;
 1683         ASSERT_BO_LOCKED(bo);
 1684         VNASSERT(bp->b_vp == NULL, bp->b_vp, ("bgetvp: not free"));
 1685 
 1686         CTR3(KTR_BUF, "bgetvp(%p) vp %p flags %X", bp, vp, bp->b_flags);
 1687         VNASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0, vp,
 1688             ("bgetvp: bp already attached! %p", bp));
 1689 
 1690         vhold(vp);
 1691         if (VFS_NEEDSGIANT(vp->v_mount) || bo->bo_flag & BO_NEEDSGIANT)
 1692                 bp->b_flags |= B_NEEDSGIANT;
 1693         bp->b_vp = vp;
 1694         bp->b_bufobj = bo;
 1695         /*
 1696          * Insert onto list for new vnode.
 1697          */
 1698         buf_vlist_add(bp, bo, BX_VNCLEAN);
 1699 }
 1700 
 1701 /*
 1702  * Disassociate a buffer from a vnode.
 1703  */
 1704 void
 1705 brelvp(struct buf *bp)
 1706 {
 1707         struct bufobj *bo;
 1708         struct vnode *vp;
 1709 
 1710         CTR3(KTR_BUF, "brelvp(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
 1711         KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
 1712 
 1713         /*
 1714          * Delete from old vnode list, if on one.
 1715          */
 1716         vp = bp->b_vp;          /* XXX */
 1717         bo = bp->b_bufobj;
 1718         BO_LOCK(bo);
 1719         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1720                 buf_vlist_remove(bp);
 1721         else
 1722                 panic("brelvp: Buffer %p not on queue.", bp);
 1723         if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 1724                 bo->bo_flag &= ~BO_ONWORKLST;
 1725                 mtx_lock(&sync_mtx);
 1726                 LIST_REMOVE(bo, bo_synclist);
 1727                 syncer_worklist_len--;
 1728                 mtx_unlock(&sync_mtx);
 1729         }
 1730         bp->b_flags &= ~B_NEEDSGIANT;
 1731         bp->b_vp = NULL;
 1732         bp->b_bufobj = NULL;
 1733         BO_UNLOCK(bo);
 1734         vdrop(vp);
 1735 }
 1736 
 1737 /*
 1738  * Add an item to the syncer work queue.
 1739  */
 1740 static void
 1741 vn_syncer_add_to_worklist(struct bufobj *bo, int delay)
 1742 {
 1743         int queue, slot;
 1744 
 1745         ASSERT_BO_LOCKED(bo);
 1746 
 1747         mtx_lock(&sync_mtx);
 1748         if (bo->bo_flag & BO_ONWORKLST)
 1749                 LIST_REMOVE(bo, bo_synclist);
 1750         else {
 1751                 bo->bo_flag |= BO_ONWORKLST;
 1752                 syncer_worklist_len++;
 1753         }
 1754 
 1755         if (delay > syncer_maxdelay - 2)
 1756                 delay = syncer_maxdelay - 2;
 1757         slot = (syncer_delayno + delay) & syncer_mask;
 1758 
 1759         queue = VFS_NEEDSGIANT(bo->__bo_vnode->v_mount) ? WI_GIANTQ :
 1760             WI_MPSAFEQ;
 1761         LIST_INSERT_HEAD(&syncer_workitem_pending[queue][slot], bo,
 1762             bo_synclist);
 1763         mtx_unlock(&sync_mtx);
 1764 }
 1765 
 1766 static int
 1767 sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
 1768 {
 1769         int error, len;
 1770 
 1771         mtx_lock(&sync_mtx);
 1772         len = syncer_worklist_len - sync_vnode_count;
 1773         mtx_unlock(&sync_mtx);
 1774         error = SYSCTL_OUT(req, &len, sizeof(len));
 1775         return (error);
 1776 }
 1777 
 1778 SYSCTL_PROC(_vfs, OID_AUTO, worklist_len, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
 1779     sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
 1780 
 1781 static struct proc *updateproc;
 1782 static void sched_sync(void);
 1783 static struct kproc_desc up_kp = {
 1784         "syncer",
 1785         sched_sync,
 1786         &updateproc
 1787 };
 1788 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp);
 1789 
 1790 static int
 1791 sync_vnode(struct synclist *slp, struct bufobj **bo, struct thread *td)
 1792 {
 1793         struct vnode *vp;
 1794         struct mount *mp;
 1795 
 1796         *bo = LIST_FIRST(slp);
 1797         if (*bo == NULL)
 1798                 return (0);
 1799         vp = (*bo)->__bo_vnode; /* XXX */
 1800         if (VOP_ISLOCKED(vp) != 0 || VI_TRYLOCK(vp) == 0)
 1801                 return (1);
 1802         /*
 1803          * We use vhold in case the vnode does not
 1804          * successfully sync.  vhold prevents the vnode from
 1805          * going away when we unlock the sync_mtx so that
 1806          * we can acquire the vnode interlock.
 1807          */
 1808         vholdl(vp);
 1809         mtx_unlock(&sync_mtx);
 1810         VI_UNLOCK(vp);
 1811         if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
 1812                 vdrop(vp);
 1813                 mtx_lock(&sync_mtx);
 1814                 return (*bo == LIST_FIRST(slp));
 1815         }
 1816         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1817         (void) VOP_FSYNC(vp, MNT_LAZY, td);
 1818         VOP_UNLOCK(vp, 0);
 1819         vn_finished_write(mp);
 1820         BO_LOCK(*bo);
 1821         if (((*bo)->bo_flag & BO_ONWORKLST) != 0) {
 1822                 /*
 1823                  * Put us back on the worklist.  The worklist
 1824                  * routine will remove us from our current
 1825                  * position and then add us back in at a later
 1826                  * position.
 1827                  */
 1828                 vn_syncer_add_to_worklist(*bo, syncdelay);
 1829         }
 1830         BO_UNLOCK(*bo);
 1831         vdrop(vp);
 1832         mtx_lock(&sync_mtx);
 1833         return (0);
 1834 }
 1835 
 1836 /*
 1837  * System filesystem synchronizer daemon.
 1838  */
 1839 static void
 1840 sched_sync(void)
 1841 {
 1842         struct synclist *gnext, *next;
 1843         struct synclist *gslp, *slp;
 1844         struct bufobj *bo;
 1845         long starttime;
 1846         struct thread *td = curthread;
 1847         int last_work_seen;
 1848         int net_worklist_len;
 1849         int syncer_final_iter;
 1850         int first_printf;
 1851         int error;
 1852 
 1853         last_work_seen = 0;
 1854         syncer_final_iter = 0;
 1855         first_printf = 1;
 1856         syncer_state = SYNCER_RUNNING;
 1857         starttime = time_uptime;
 1858         td->td_pflags |= TDP_NORUNNINGBUF;
 1859 
 1860         EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
 1861             SHUTDOWN_PRI_LAST);
 1862 
 1863         mtx_lock(&sync_mtx);
 1864         for (;;) {
 1865                 if (syncer_state == SYNCER_FINAL_DELAY &&
 1866                     syncer_final_iter == 0) {
 1867                         mtx_unlock(&sync_mtx);
 1868                         kproc_suspend_check(td->td_proc);
 1869                         mtx_lock(&sync_mtx);
 1870                 }
 1871                 net_worklist_len = syncer_worklist_len - sync_vnode_count;
 1872                 if (syncer_state != SYNCER_RUNNING &&
 1873                     starttime != time_uptime) {
 1874                         if (first_printf) {
 1875                                 printf("\nSyncing disks, vnodes remaining...");
 1876                                 first_printf = 0;
 1877                         }
 1878                         printf("%d ", net_worklist_len);
 1879                 }
 1880                 starttime = time_uptime;
 1881 
 1882                 /*
 1883                  * Push files whose dirty time has expired.  Be careful
 1884                  * of interrupt race on slp queue.
 1885                  *
 1886                  * Skip over empty worklist slots when shutting down.
 1887                  */
 1888                 do {
 1889                         slp = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1890                         gslp = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1891                         syncer_delayno += 1;
 1892                         if (syncer_delayno == syncer_maxdelay)
 1893                                 syncer_delayno = 0;
 1894                         next = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1895                         gnext = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1896                         /*
 1897                          * If the worklist has wrapped since the
 1898                          * it was emptied of all but syncer vnodes,
 1899                          * switch to the FINAL_DELAY state and run
 1900                          * for one more second.
 1901                          */
 1902                         if (syncer_state == SYNCER_SHUTTING_DOWN &&
 1903                             net_worklist_len == 0 &&
 1904                             last_work_seen == syncer_delayno) {
 1905                                 syncer_state = SYNCER_FINAL_DELAY;
 1906                                 syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
 1907                         }
 1908                 } while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
 1909                     LIST_EMPTY(gslp) && syncer_worklist_len > 0);
 1910 
 1911                 /*
 1912                  * Keep track of the last time there was anything
 1913                  * on the worklist other than syncer vnodes.
 1914                  * Return to the SHUTTING_DOWN state if any
 1915                  * new work appears.
 1916                  */
 1917                 if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
 1918                         last_work_seen = syncer_delayno;
 1919                 if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
 1920                         syncer_state = SYNCER_SHUTTING_DOWN;
 1921                 while (!LIST_EMPTY(slp)) {
 1922                         error = sync_vnode(slp, &bo, td);
 1923                         if (error == 1) {
 1924                                 LIST_REMOVE(bo, bo_synclist);
 1925                                 LIST_INSERT_HEAD(next, bo, bo_synclist);
 1926                                 continue;
 1927                         }
 1928 
 1929                         if (first_printf == 0)
 1930                                 wdog_kern_pat(WD_LASTVAL);
 1931 
 1932                 }
 1933                 if (!LIST_EMPTY(gslp)) {
 1934                         mtx_unlock(&sync_mtx);
 1935                         mtx_lock(&Giant);
 1936                         mtx_lock(&sync_mtx);
 1937                         while (!LIST_EMPTY(gslp)) {
 1938                                 error = sync_vnode(gslp, &bo, td);
 1939                                 if (error == 1) {
 1940                                         LIST_REMOVE(bo, bo_synclist);
 1941                                         LIST_INSERT_HEAD(gnext, bo,
 1942                                             bo_synclist);
 1943                                         continue;
 1944                                 }
 1945                         }
 1946                         mtx_unlock(&Giant);
 1947                 }
 1948                 if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
 1949                         syncer_final_iter--;
 1950                 /*
 1951                  * The variable rushjob allows the kernel to speed up the
 1952                  * processing of the filesystem syncer process. A rushjob
 1953                  * value of N tells the filesystem syncer to process the next
 1954                  * N seconds worth of work on its queue ASAP. Currently rushjob
 1955                  * is used by the soft update code to speed up the filesystem
 1956                  * syncer process when the incore state is getting so far
 1957                  * ahead of the disk that the kernel memory pool is being
 1958                  * threatened with exhaustion.
 1959                  */
 1960                 if (rushjob > 0) {
 1961                         rushjob -= 1;
 1962                         continue;
 1963                 }
 1964                 /*
 1965                  * Just sleep for a short period of time between
 1966                  * iterations when shutting down to allow some I/O
 1967                  * to happen.
 1968                  *
 1969                  * If it has taken us less than a second to process the
 1970                  * current work, then wait. Otherwise start right over
 1971                  * again. We can still lose time if any single round
 1972                  * takes more than two seconds, but it does not really
 1973                  * matter as we are just trying to generally pace the
 1974                  * filesystem activity.
 1975                  */
 1976                 if (syncer_state != SYNCER_RUNNING ||
 1977                     time_uptime == starttime) {
 1978                         thread_lock(td);
 1979                         sched_prio(td, PPAUSE);
 1980                         thread_unlock(td);
 1981                 }
 1982                 if (syncer_state != SYNCER_RUNNING)
 1983                         cv_timedwait(&sync_wakeup, &sync_mtx,
 1984                             hz / SYNCER_SHUTDOWN_SPEEDUP);
 1985                 else if (time_uptime == starttime)
 1986                         cv_timedwait(&sync_wakeup, &sync_mtx, hz);
 1987         }
 1988 }
 1989 
 1990 /*
 1991  * Request the syncer daemon to speed up its work.
 1992  * We never push it to speed up more than half of its
 1993  * normal turn time, otherwise it could take over the cpu.
 1994  */
 1995 int
 1996 speedup_syncer(void)
 1997 {
 1998         int ret = 0;
 1999 
 2000         mtx_lock(&sync_mtx);
 2001         if (rushjob < syncdelay / 2) {
 2002                 rushjob += 1;
 2003                 stat_rush_requests += 1;
 2004                 ret = 1;
 2005         }
 2006         mtx_unlock(&sync_mtx);
 2007         cv_broadcast(&sync_wakeup);
 2008         return (ret);
 2009 }
 2010 
 2011 /*
 2012  * Tell the syncer to speed up its work and run though its work
 2013  * list several times, then tell it to shut down.
 2014  */
 2015 static void
 2016 syncer_shutdown(void *arg, int howto)
 2017 {
 2018 
 2019         if (howto & RB_NOSYNC)
 2020                 return;
 2021         mtx_lock(&sync_mtx);
 2022         syncer_state = SYNCER_SHUTTING_DOWN;
 2023         rushjob = 0;
 2024         mtx_unlock(&sync_mtx);
 2025         cv_broadcast(&sync_wakeup);
 2026         kproc_shutdown(arg, howto);
 2027 }
 2028 
 2029 /*
 2030  * Reassign a buffer from one vnode to another.
 2031  * Used to assign file specific control information
 2032  * (indirect blocks) to the vnode to which they belong.
 2033  */
 2034 void
 2035 reassignbuf(struct buf *bp)
 2036 {
 2037         struct vnode *vp;
 2038         struct bufobj *bo;
 2039         int delay;
 2040 #ifdef INVARIANTS
 2041         struct bufv *bv;
 2042 #endif
 2043 
 2044         vp = bp->b_vp;
 2045         bo = bp->b_bufobj;
 2046         ++reassignbufcalls;
 2047 
 2048         CTR3(KTR_BUF, "reassignbuf(%p) vp %p flags %X",
 2049             bp, bp->b_vp, bp->b_flags);
 2050         /*
 2051          * B_PAGING flagged buffers cannot be reassigned because their vp
 2052          * is not fully linked in.
 2053          */
 2054         if (bp->b_flags & B_PAGING)
 2055                 panic("cannot reassign paging buffer");
 2056 
 2057         /*
 2058          * Delete from old vnode list, if on one.
 2059          */
 2060         BO_LOCK(bo);
 2061         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 2062                 buf_vlist_remove(bp);
 2063         else
 2064                 panic("reassignbuf: Buffer %p not on queue.", bp);
 2065         /*
 2066          * If dirty, put on list of dirty buffers; otherwise insert onto list
 2067          * of clean buffers.
 2068          */
 2069         if (bp->b_flags & B_DELWRI) {
 2070                 if ((bo->bo_flag & BO_ONWORKLST) == 0) {
 2071                         switch (vp->v_type) {
 2072                         case VDIR:
 2073                                 delay = dirdelay;
 2074                                 break;
 2075                         case VCHR:
 2076                                 delay = metadelay;
 2077                                 break;
 2078                         default:
 2079                                 delay = filedelay;
 2080                         }
 2081                         vn_syncer_add_to_worklist(bo, delay);
 2082                 }
 2083                 buf_vlist_add(bp, bo, BX_VNDIRTY);
 2084         } else {
 2085                 buf_vlist_add(bp, bo, BX_VNCLEAN);
 2086 
 2087                 if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 2088                         mtx_lock(&sync_mtx);
 2089                         LIST_REMOVE(bo, bo_synclist);
 2090                         syncer_worklist_len--;
 2091                         mtx_unlock(&sync_mtx);
 2092                         bo->bo_flag &= ~BO_ONWORKLST;
 2093                 }
 2094         }
 2095 #ifdef INVARIANTS
 2096         bv = &bo->bo_clean;
 2097         bp = TAILQ_FIRST(&bv->bv_hd);
 2098         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2099             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2100         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 2101         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2102             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2103         bv = &bo->bo_dirty;
 2104         bp = TAILQ_FIRST(&bv->bv_hd);
 2105         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2106             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2107         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 2108         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2109             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2110 #endif
 2111         BO_UNLOCK(bo);
 2112 }
 2113 
 2114 /*
 2115  * Increment the use and hold counts on the vnode, taking care to reference
 2116  * the driver's usecount if this is a chardev.  The vholdl() will remove
 2117  * the vnode from the free list if it is presently free.  Requires the
 2118  * vnode interlock and returns with it held.
 2119  */
 2120 static void
 2121 v_incr_usecount(struct vnode *vp)
 2122 {
 2123 
 2124         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2125         vp->v_usecount++;
 2126         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2127                 dev_lock();
 2128                 vp->v_rdev->si_usecount++;
 2129                 dev_unlock();
 2130         }
 2131         vholdl(vp);
 2132 }
 2133 
 2134 /*
 2135  * Turn a holdcnt into a use+holdcnt such that only one call to
 2136  * v_decr_usecount is needed.
 2137  */
 2138 static void
 2139 v_upgrade_usecount(struct vnode *vp)
 2140 {
 2141 
 2142         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2143         vp->v_usecount++;
 2144         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2145                 dev_lock();
 2146                 vp->v_rdev->si_usecount++;
 2147                 dev_unlock();
 2148         }
 2149 }
 2150 
 2151 /*
 2152  * Decrement the vnode use and hold count along with the driver's usecount
 2153  * if this is a chardev.  The vdropl() below releases the vnode interlock
 2154  * as it may free the vnode.
 2155  */
 2156 static void
 2157 v_decr_usecount(struct vnode *vp)
 2158 {
 2159 
 2160         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2161         VNASSERT(vp->v_usecount > 0, vp,
 2162             ("v_decr_usecount: negative usecount"));
 2163         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2164         vp->v_usecount--;
 2165         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2166                 dev_lock();
 2167                 vp->v_rdev->si_usecount--;
 2168                 dev_unlock();
 2169         }
 2170         vdropl(vp);
 2171 }
 2172 
 2173 /*
 2174  * Decrement only the use count and driver use count.  This is intended to
 2175  * be paired with a follow on vdropl() to release the remaining hold count.
 2176  * In this way we may vgone() a vnode with a 0 usecount without risk of
 2177  * having it end up on a free list because the hold count is kept above 0.
 2178  */
 2179 static void
 2180 v_decr_useonly(struct vnode *vp)
 2181 {
 2182 
 2183         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2184         VNASSERT(vp->v_usecount > 0, vp,
 2185             ("v_decr_useonly: negative usecount"));
 2186         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2187         vp->v_usecount--;
 2188         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2189                 dev_lock();
 2190                 vp->v_rdev->si_usecount--;
 2191                 dev_unlock();
 2192         }
 2193 }
 2194 
 2195 /*
 2196  * Grab a particular vnode from the free list, increment its
 2197  * reference count and lock it.  VI_DOOMED is set if the vnode
 2198  * is being destroyed.  Only callers who specify LK_RETRY will
 2199  * see doomed vnodes.  If inactive processing was delayed in
 2200  * vput try to do it here.
 2201  */
 2202 int
 2203 vget(struct vnode *vp, int flags, struct thread *td)
 2204 {
 2205         int error;
 2206 
 2207         error = 0;
 2208         VFS_ASSERT_GIANT(vp->v_mount);
 2209         VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
 2210             ("vget: invalid lock operation"));
 2211         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 2212 
 2213         if ((flags & LK_INTERLOCK) == 0)
 2214                 VI_LOCK(vp);
 2215         vholdl(vp);
 2216         if ((error = vn_lock(vp, flags | LK_INTERLOCK)) != 0) {
 2217                 vdrop(vp);
 2218                 CTR2(KTR_VFS, "%s: impossible to lock vnode %p", __func__,
 2219                     vp);
 2220                 return (error);
 2221         }
 2222         if (vp->v_iflag & VI_DOOMED && (flags & LK_RETRY) == 0)
 2223                 panic("vget: vn_lock failed to return ENOENT\n");
 2224         VI_LOCK(vp);
 2225         /* Upgrade our holdcnt to a usecount. */
 2226         v_upgrade_usecount(vp);
 2227         /*
 2228          * We don't guarantee that any particular close will
 2229          * trigger inactive processing so just make a best effort
 2230          * here at preventing a reference to a removed file.  If
 2231          * we don't succeed no harm is done.
 2232          */
 2233         if (vp->v_iflag & VI_OWEINACT) {
 2234                 if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE && 
 2235                     (flags & LK_NOWAIT) == 0)
 2236                         vinactive(vp, td);
 2237                 vp->v_iflag &= ~VI_OWEINACT;
 2238         }
 2239         VI_UNLOCK(vp);
 2240         return (0);
 2241 }
 2242 
 2243 /*
 2244  * Increase the reference count of a vnode.
 2245  */
 2246 void
 2247 vref(struct vnode *vp)
 2248 {
 2249 
 2250         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2251         VI_LOCK(vp);
 2252         v_incr_usecount(vp);
 2253         VI_UNLOCK(vp);
 2254 }
 2255 
 2256 /*
 2257  * Return reference count of a vnode.
 2258  *
 2259  * The results of this call are only guaranteed when some mechanism other
 2260  * than the VI lock is used to stop other processes from gaining references
 2261  * to the vnode.  This may be the case if the caller holds the only reference.
 2262  * This is also useful when stale data is acceptable as race conditions may
 2263  * be accounted for by some other means.
 2264  */
 2265 int
 2266 vrefcnt(struct vnode *vp)
 2267 {
 2268         int usecnt;
 2269 
 2270         VI_LOCK(vp);
 2271         usecnt = vp->v_usecount;
 2272         VI_UNLOCK(vp);
 2273 
 2274         return (usecnt);
 2275 }
 2276 
 2277 #define VPUTX_VRELE     1
 2278 #define VPUTX_VPUT      2
 2279 #define VPUTX_VUNREF    3
 2280 
 2281 static void
 2282 vputx(struct vnode *vp, int func)
 2283 {
 2284         int error;
 2285 
 2286         KASSERT(vp != NULL, ("vputx: null vp"));
 2287         if (func == VPUTX_VUNREF)
 2288                 ASSERT_VOP_LOCKED(vp, "vunref");
 2289         else if (func == VPUTX_VPUT)
 2290                 ASSERT_VOP_LOCKED(vp, "vput");
 2291         else
 2292                 KASSERT(func == VPUTX_VRELE, ("vputx: wrong func"));
 2293         VFS_ASSERT_GIANT(vp->v_mount);
 2294         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2295         VI_LOCK(vp);
 2296 
 2297         /* Skip this v_writecount check if we're going to panic below. */
 2298         VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
 2299             ("vputx: missed vn_close"));
 2300         error = 0;
 2301 
 2302         if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
 2303             vp->v_usecount == 1)) {
 2304                 if (func == VPUTX_VPUT)
 2305                         VOP_UNLOCK(vp, 0);
 2306                 v_decr_usecount(vp);
 2307                 return;
 2308         }
 2309 
 2310         if (vp->v_usecount != 1) {
 2311                 vprint("vputx: negative ref count", vp);
 2312                 panic("vputx: negative ref cnt");
 2313         }
 2314         CTR2(KTR_VFS, "%s: return vnode %p to the freelist", __func__, vp);
 2315         /*
 2316          * We want to hold the vnode until the inactive finishes to
 2317          * prevent vgone() races.  We drop the use count here and the
 2318          * hold count below when we're done.
 2319          */
 2320         v_decr_useonly(vp);
 2321         /*
 2322          * We must call VOP_INACTIVE with the node locked. Mark
 2323          * as VI_DOINGINACT to avoid recursion.
 2324          */
 2325         vp->v_iflag |= VI_OWEINACT;
 2326         switch (func) {
 2327         case VPUTX_VRELE:
 2328                 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK);
 2329                 VI_LOCK(vp);
 2330                 break;
 2331         case VPUTX_VPUT:
 2332                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
 2333                         error = VOP_LOCK(vp, LK_UPGRADE | LK_INTERLOCK |
 2334                             LK_NOWAIT);
 2335                         VI_LOCK(vp);
 2336                 }
 2337                 break;
 2338         case VPUTX_VUNREF:
 2339                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 2340                         error = EBUSY;
 2341                 break;
 2342         }
 2343         if (vp->v_usecount > 0)
 2344                 vp->v_iflag &= ~VI_OWEINACT;
 2345         if (error == 0) {
 2346                 if (vp->v_iflag & VI_OWEINACT)
 2347                         vinactive(vp, curthread);
 2348                 if (func != VPUTX_VUNREF)
 2349                         VOP_UNLOCK(vp, 0);
 2350         }
 2351         vdropl(vp);
 2352 }
 2353 
 2354 /*
 2355  * Vnode put/release.
 2356  * If count drops to zero, call inactive routine and return to freelist.
 2357  */
 2358 void
 2359 vrele(struct vnode *vp)
 2360 {
 2361 
 2362         vputx(vp, VPUTX_VRELE);
 2363 }
 2364 
 2365 /*
 2366  * Release an already locked vnode.  This give the same effects as
 2367  * unlock+vrele(), but takes less time and avoids releasing and
 2368  * re-aquiring the lock (as vrele() acquires the lock internally.)
 2369  */
 2370 void
 2371 vput(struct vnode *vp)
 2372 {
 2373 
 2374         vputx(vp, VPUTX_VPUT);
 2375 }
 2376 
 2377 /*
 2378  * Release an exclusively locked vnode. Do not unlock the vnode lock.
 2379  */
 2380 void
 2381 vunref(struct vnode *vp)
 2382 {
 2383 
 2384         vputx(vp, VPUTX_VUNREF);
 2385 }
 2386 
 2387 /*
 2388  * Somebody doesn't want the vnode recycled.
 2389  */
 2390 void
 2391 vhold(struct vnode *vp)
 2392 {
 2393 
 2394         VI_LOCK(vp);
 2395         vholdl(vp);
 2396         VI_UNLOCK(vp);
 2397 }
 2398 
 2399 void
 2400 vholdl(struct vnode *vp)
 2401 {
 2402 
 2403         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2404         vp->v_holdcnt++;
 2405         if (VSHOULDBUSY(vp))
 2406                 vbusy(vp);
 2407 }
 2408 
 2409 /*
 2410  * Note that there is one less who cares about this vnode.  vdrop() is the
 2411  * opposite of vhold().
 2412  */
 2413 void
 2414 vdrop(struct vnode *vp)
 2415 {
 2416 
 2417         VI_LOCK(vp);
 2418         vdropl(vp);
 2419 }
 2420 
 2421 /*
 2422  * Drop the hold count of the vnode.  If this is the last reference to
 2423  * the vnode we will free it if it has been vgone'd otherwise it is
 2424  * placed on the free list.
 2425  */
 2426 void
 2427 vdropl(struct vnode *vp)
 2428 {
 2429 
 2430         ASSERT_VI_LOCKED(vp, "vdropl");
 2431         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2432         if (vp->v_holdcnt <= 0)
 2433                 panic("vdrop: holdcnt %d", vp->v_holdcnt);
 2434         vp->v_holdcnt--;
 2435         if (vp->v_holdcnt == 0) {
 2436                 if (vp->v_iflag & VI_DOOMED) {
 2437                         CTR2(KTR_VFS, "%s: destroying the vnode %p", __func__,
 2438                             vp);
 2439                         vdestroy(vp);
 2440                         return;
 2441                 } else
 2442                         vfree(vp);
 2443         }
 2444         VI_UNLOCK(vp);
 2445 }
 2446 
 2447 /*
 2448  * Call VOP_INACTIVE on the vnode and manage the DOINGINACT and OWEINACT
 2449  * flags.  DOINGINACT prevents us from recursing in calls to vinactive.
 2450  * OWEINACT tracks whether a vnode missed a call to inactive due to a
 2451  * failed lock upgrade.
 2452  */
 2453 void
 2454 vinactive(struct vnode *vp, struct thread *td)
 2455 {
 2456 
 2457         ASSERT_VOP_ELOCKED(vp, "vinactive");
 2458         ASSERT_VI_LOCKED(vp, "vinactive");
 2459         VNASSERT((vp->v_iflag & VI_DOINGINACT) == 0, vp,
 2460             ("vinactive: recursed on VI_DOINGINACT"));
 2461         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2462         vp->v_iflag |= VI_DOINGINACT;
 2463         vp->v_iflag &= ~VI_OWEINACT;
 2464         VI_UNLOCK(vp);
 2465         VOP_INACTIVE(vp, td);
 2466         VI_LOCK(vp);
 2467         VNASSERT(vp->v_iflag & VI_DOINGINACT, vp,
 2468             ("vinactive: lost VI_DOINGINACT"));
 2469         vp->v_iflag &= ~VI_DOINGINACT;
 2470 }
 2471 
 2472 /*
 2473  * Remove any vnodes in the vnode table belonging to mount point mp.
 2474  *
 2475  * If FORCECLOSE is not specified, there should not be any active ones,
 2476  * return error if any are found (nb: this is a user error, not a
 2477  * system error). If FORCECLOSE is specified, detach any active vnodes
 2478  * that are found.
 2479  *
 2480  * If WRITECLOSE is set, only flush out regular file vnodes open for
 2481  * writing.
 2482  *
 2483  * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
 2484  *
 2485  * `rootrefs' specifies the base reference count for the root vnode
 2486  * of this filesystem. The root vnode is considered busy if its
 2487  * v_usecount exceeds this value. On a successful return, vflush(, td)
 2488  * will call vrele() on the root vnode exactly rootrefs times.
 2489  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
 2490  * be zero.
 2491  */
 2492 #ifdef DIAGNOSTIC
 2493 static int busyprt = 0;         /* print out busy vnodes */
 2494 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "Print out busy vnodes");
 2495 #endif
 2496 
 2497 int
 2498 vflush( struct mount *mp, int rootrefs, int flags, struct thread *td)
 2499 {
 2500         struct vnode *vp, *mvp, *rootvp = NULL;
 2501         struct vattr vattr;
 2502         int busy = 0, error;
 2503 
 2504         CTR4(KTR_VFS, "%s: mp %p with rootrefs %d and flags %d", __func__, mp,
 2505             rootrefs, flags);
 2506         if (rootrefs > 0) {
 2507                 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
 2508                     ("vflush: bad args"));
 2509                 /*
 2510                  * Get the filesystem root vnode. We can vput() it
 2511                  * immediately, since with rootrefs > 0, it won't go away.
 2512                  */
 2513                 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rootvp)) != 0) {
 2514                         CTR2(KTR_VFS, "%s: vfs_root lookup failed with %d",
 2515                             __func__, error);
 2516                         return (error);
 2517                 }
 2518                 vput(rootvp);
 2519 
 2520         }
 2521         MNT_ILOCK(mp);
 2522 loop:
 2523         MNT_VNODE_FOREACH(vp, mp, mvp) {
 2524 
 2525                 VI_LOCK(vp);
 2526                 vholdl(vp);
 2527                 MNT_IUNLOCK(mp);
 2528                 error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE);
 2529                 if (error) {
 2530                         vdrop(vp);
 2531                         MNT_ILOCK(mp);
 2532                         MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);
 2533                         goto loop;
 2534                 }
 2535                 /*
 2536                  * Skip over a vnodes marked VV_SYSTEM.
 2537                  */
 2538                 if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
 2539                         VOP_UNLOCK(vp, 0);
 2540                         vdrop(vp);
 2541                         MNT_ILOCK(mp);
 2542                         continue;
 2543                 }
 2544                 /*
 2545                  * If WRITECLOSE is set, flush out unlinked but still open
 2546                  * files (even if open only for reading) and regular file
 2547                  * vnodes open for writing.
 2548                  */
 2549                 if (flags & WRITECLOSE) {
 2550                         if (vp->v_object != NULL) {
 2551                                 VM_OBJECT_LOCK(vp->v_object);
 2552                                 vm_object_page_clean(vp->v_object, 0, 0, 0);
 2553                                 VM_OBJECT_UNLOCK(vp->v_object);
 2554                         }
 2555                         error = VOP_FSYNC(vp, MNT_WAIT, td);
 2556                         if (error != 0) {
 2557                                 VOP_UNLOCK(vp, 0);
 2558                                 vdrop(vp);
 2559                                 MNT_VNODE_FOREACH_ABORT(mp, mvp);
 2560                                 return (error);
 2561                         }
 2562                         error = VOP_GETATTR(vp, &vattr, td->td_ucred);
 2563                         VI_LOCK(vp);
 2564 
 2565                         if ((vp->v_type == VNON ||
 2566                             (error == 0 && vattr.va_nlink > 0)) &&
 2567                             (vp->v_writecount == 0 || vp->v_type != VREG)) {
 2568                                 VOP_UNLOCK(vp, 0);
 2569                                 vdropl(vp);
 2570                                 MNT_ILOCK(mp);
 2571                                 continue;
 2572                         }
 2573                 } else
 2574                         VI_LOCK(vp);
 2575                 /*
 2576                  * With v_usecount == 0, all we need to do is clear out the
 2577                  * vnode data structures and we are done.
 2578                  *
 2579                  * If FORCECLOSE is set, forcibly close the vnode.
 2580                  */
 2581                 if (vp->v_usecount == 0 || (flags & FORCECLOSE)) {
 2582                         VNASSERT(vp->v_usecount == 0 ||
 2583                             (vp->v_type != VCHR && vp->v_type != VBLK), vp,
 2584                             ("device VNODE %p is FORCECLOSED", vp));
 2585                         vgonel(vp);
 2586                 } else {
 2587                         busy++;
 2588 #ifdef DIAGNOSTIC
 2589                         if (busyprt)
 2590                                 vprint("vflush: busy vnode", vp);
 2591 #endif
 2592                 }
 2593                 VOP_UNLOCK(vp, 0);
 2594                 vdropl(vp);
 2595                 MNT_ILOCK(mp);
 2596         }
 2597         MNT_IUNLOCK(mp);
 2598         if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
 2599                 /*
 2600                  * If just the root vnode is busy, and if its refcount
 2601                  * is equal to `rootrefs', then go ahead and kill it.
 2602                  */
 2603                 VI_LOCK(rootvp);
 2604                 KASSERT(busy > 0, ("vflush: not busy"));
 2605                 VNASSERT(rootvp->v_usecount >= rootrefs, rootvp,
 2606                     ("vflush: usecount %d < rootrefs %d",
 2607                      rootvp->v_usecount, rootrefs));
 2608                 if (busy == 1 && rootvp->v_usecount == rootrefs) {
 2609                         VOP_LOCK(rootvp, LK_EXCLUSIVE|LK_INTERLOCK);
 2610                         vgone(rootvp);
 2611                         VOP_UNLOCK(rootvp, 0);
 2612                         busy = 0;
 2613                 } else
 2614                         VI_UNLOCK(rootvp);
 2615         }
 2616         if (busy) {
 2617                 CTR2(KTR_VFS, "%s: failing as %d vnodes are busy", __func__,
 2618                     busy);
 2619                 return (EBUSY);
 2620         }
 2621         for (; rootrefs > 0; rootrefs--)
 2622                 vrele(rootvp);
 2623         return (0);
 2624 }
 2625 
 2626 /*
 2627  * Recycle an unused vnode to the front of the free list.
 2628  */
 2629 int
 2630 vrecycle(struct vnode *vp, struct thread *td)
 2631 {
 2632         int recycled;
 2633 
 2634         ASSERT_VOP_ELOCKED(vp, "vrecycle");
 2635         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2636         recycled = 0;
 2637         VI_LOCK(vp);
 2638         if (vp->v_usecount == 0) {
 2639                 recycled = 1;
 2640                 vgonel(vp);
 2641         }
 2642         VI_UNLOCK(vp);
 2643         return (recycled);
 2644 }
 2645 
 2646 /*
 2647  * Eliminate all activity associated with a vnode
 2648  * in preparation for reuse.
 2649  */
 2650 void
 2651 vgone(struct vnode *vp)
 2652 {
 2653         VI_LOCK(vp);
 2654         vgonel(vp);
 2655         VI_UNLOCK(vp);
 2656 }
 2657 
 2658 /*
 2659  * vgone, with the vp interlock held.
 2660  */
 2661 void
 2662 vgonel(struct vnode *vp)
 2663 {
 2664         struct thread *td;
 2665         int oweinact;
 2666         int active;
 2667         struct mount *mp;
 2668 
 2669         ASSERT_VOP_ELOCKED(vp, "vgonel");
 2670         ASSERT_VI_LOCKED(vp, "vgonel");
 2671         VNASSERT(vp->v_holdcnt, vp,
 2672             ("vgonel: vp %p has no reference.", vp));
 2673         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2674         td = curthread;
 2675 
 2676         /*
 2677          * Don't vgonel if we're already doomed.
 2678          */
 2679         if (vp->v_iflag & VI_DOOMED)
 2680                 return;
 2681         vp->v_iflag |= VI_DOOMED;
 2682         /*
 2683          * Check to see if the vnode is in use.  If so, we have to call
 2684          * VOP_CLOSE() and VOP_INACTIVE().
 2685          */
 2686         active = vp->v_usecount;
 2687         oweinact = (vp->v_iflag & VI_OWEINACT);
 2688         VI_UNLOCK(vp);
 2689         /*
 2690          * Clean out any buffers associated with the vnode.
 2691          * If the flush fails, just toss the buffers.
 2692          */
 2693         mp = NULL;
 2694         if (!TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd))
 2695                 (void) vn_start_secondary_write(vp, &mp, V_WAIT);
 2696         if (vinvalbuf(vp, V_SAVE, 0, 0) != 0)
 2697                 vinvalbuf(vp, 0, 0, 0);
 2698 
 2699         /*
 2700          * If purging an active vnode, it must be closed and
 2701          * deactivated before being reclaimed.
 2702          */
 2703         if (active)
 2704                 VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
 2705         if (oweinact || active) {
 2706                 VI_LOCK(vp);
 2707                 if ((vp->v_iflag & VI_DOINGINACT) == 0)
 2708                         vinactive(vp, td);
 2709                 VI_UNLOCK(vp);
 2710         }
 2711         /*
 2712          * Reclaim the vnode.
 2713          */
 2714         if (VOP_RECLAIM(vp, td))
 2715                 panic("vgone: cannot reclaim");
 2716         if (mp != NULL)
 2717                 vn_finished_secondary_write(mp);
 2718         VNASSERT(vp->v_object == NULL, vp,
 2719             ("vop_reclaim left v_object vp=%p, tag=%s", vp, vp->v_tag));
 2720         /*
 2721          * Clear the advisory locks and wake up waiting threads.
 2722          */
 2723         lf_purgelocks(vp, &(vp->v_lockf));
 2724         /*
 2725          * Delete from old mount point vnode list.
 2726          */
 2727         delmntque(vp);
 2728         cache_purge(vp);
 2729         /*
 2730          * Done with purge, reset to the standard lock and invalidate
 2731          * the vnode.
 2732          */
 2733         VI_LOCK(vp);
 2734         vp->v_vnlock = &vp->v_lock;
 2735         vp->v_op = &dead_vnodeops;
 2736         vp->v_tag = "none";
 2737         vp->v_type = VBAD;
 2738 }
 2739 
 2740 /*
 2741  * Calculate the total number of references to a special device.
 2742  */
 2743 int
 2744 vcount(struct vnode *vp)
 2745 {
 2746         int count;
 2747 
 2748         dev_lock();
 2749         count = vp->v_rdev->si_usecount;
 2750         dev_unlock();
 2751         return (count);
 2752 }
 2753 
 2754 /*
 2755  * Same as above, but using the struct cdev *as argument
 2756  */
 2757 int
 2758 count_dev(struct cdev *dev)
 2759 {
 2760         int count;
 2761 
 2762         dev_lock();
 2763         count = dev->si_usecount;
 2764         dev_unlock();
 2765         return(count);
 2766 }
 2767 
 2768 /*
 2769  * Print out a description of a vnode.
 2770  */
 2771 static char *typename[] =
 2772 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD",
 2773  "VMARKER"};
 2774 
 2775 void
 2776 vn_printf(struct vnode *vp, const char *fmt, ...)
 2777 {
 2778         va_list ap;
 2779         char buf[256], buf2[16];
 2780         u_long flags;
 2781 
 2782         va_start(ap, fmt);
 2783         vprintf(fmt, ap);
 2784         va_end(ap);
 2785         printf("%p: ", (void *)vp);
 2786         printf("tag %s, type %s\n", vp->v_tag, typename[vp->v_type]);
 2787         printf("    usecount %d, writecount %d, refcount %d mountedhere %p\n",
 2788             vp->v_usecount, vp->v_writecount, vp->v_holdcnt, vp->v_mountedhere);
 2789         buf[0] = '\0';
 2790         buf[1] = '\0';
 2791         if (vp->v_vflag & VV_ROOT)
 2792                 strlcat(buf, "|VV_ROOT", sizeof(buf));
 2793         if (vp->v_vflag & VV_ISTTY)
 2794                 strlcat(buf, "|VV_ISTTY", sizeof(buf));
 2795         if (vp->v_vflag & VV_NOSYNC)
 2796                 strlcat(buf, "|VV_NOSYNC", sizeof(buf));
 2797         if (vp->v_vflag & VV_CACHEDLABEL)
 2798                 strlcat(buf, "|VV_CACHEDLABEL", sizeof(buf));
 2799         if (vp->v_vflag & VV_TEXT)
 2800                 strlcat(buf, "|VV_TEXT", sizeof(buf));
 2801         if (vp->v_vflag & VV_COPYONWRITE)
 2802                 strlcat(buf, "|VV_COPYONWRITE", sizeof(buf));
 2803         if (vp->v_vflag & VV_SYSTEM)
 2804                 strlcat(buf, "|VV_SYSTEM", sizeof(buf));
 2805         if (vp->v_vflag & VV_PROCDEP)
 2806                 strlcat(buf, "|VV_PROCDEP", sizeof(buf));
 2807         if (vp->v_vflag & VV_NOKNOTE)
 2808                 strlcat(buf, "|VV_NOKNOTE", sizeof(buf));
 2809         if (vp->v_vflag & VV_DELETED)
 2810                 strlcat(buf, "|VV_DELETED", sizeof(buf));
 2811         if (vp->v_vflag & VV_MD)
 2812                 strlcat(buf, "|VV_MD", sizeof(buf));
 2813         flags = vp->v_vflag & ~(VV_ROOT | VV_ISTTY | VV_NOSYNC |
 2814             VV_CACHEDLABEL | VV_TEXT | VV_COPYONWRITE | VV_SYSTEM | VV_PROCDEP |
 2815             VV_NOKNOTE | VV_DELETED | VV_MD);
 2816         if (flags != 0) {
 2817                 snprintf(buf2, sizeof(buf2), "|VV(0x%lx)", flags);
 2818                 strlcat(buf, buf2, sizeof(buf));
 2819         }
 2820         if (vp->v_iflag & VI_MOUNT)
 2821                 strlcat(buf, "|VI_MOUNT", sizeof(buf));
 2822         if (vp->v_iflag & VI_AGE)
 2823                 strlcat(buf, "|VI_AGE", sizeof(buf));
 2824         if (vp->v_iflag & VI_DOOMED)
 2825                 strlcat(buf, "|VI_DOOMED", sizeof(buf));
 2826         if (vp->v_iflag & VI_FREE)
 2827                 strlcat(buf, "|VI_FREE", sizeof(buf));
 2828         if (vp->v_iflag & VI_DOINGINACT)
 2829                 strlcat(buf, "|VI_DOINGINACT", sizeof(buf));
 2830         if (vp->v_iflag & VI_OWEINACT)
 2831                 strlcat(buf, "|VI_OWEINACT", sizeof(buf));
 2832         flags = vp->v_iflag & ~(VI_MOUNT | VI_AGE | VI_DOOMED | VI_FREE |
 2833             VI_DOINGINACT | VI_OWEINACT);
 2834         if (flags != 0) {
 2835                 snprintf(buf2, sizeof(buf2), "|VI(0x%lx)", flags);
 2836                 strlcat(buf, buf2, sizeof(buf));
 2837         }
 2838         printf("    flags (%s)\n", buf + 1);
 2839         if (mtx_owned(VI_MTX(vp)))
 2840                 printf(" VI_LOCKed");
 2841         if (vp->v_object != NULL)
 2842                 printf("    v_object %p ref %d pages %d\n",
 2843                     vp->v_object, vp->v_object->ref_count,
 2844                     vp->v_object->resident_page_count);
 2845         printf("    ");
 2846         lockmgr_printinfo(vp->v_vnlock);
 2847         if (vp->v_data != NULL)
 2848                 VOP_PRINT(vp);
 2849 }
 2850 
 2851 #ifdef DDB
 2852 /*
 2853  * List all of the locked vnodes in the system.
 2854  * Called when debugging the kernel.
 2855  */
 2856 DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
 2857 {
 2858         struct mount *mp, *nmp;
 2859         struct vnode *vp;
 2860 
 2861         /*
 2862          * Note: because this is DDB, we can't obey the locking semantics
 2863          * for these structures, which means we could catch an inconsistent
 2864          * state and dereference a nasty pointer.  Not much to be done
 2865          * about that.
 2866          */
 2867         db_printf("Locked vnodes\n");
 2868         for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
 2869                 nmp = TAILQ_NEXT(mp, mnt_list);
 2870                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2871                         if (vp->v_type != VMARKER &&
 2872                             VOP_ISLOCKED(vp))
 2873                                 vprint("", vp);
 2874                 }
 2875                 nmp = TAILQ_NEXT(mp, mnt_list);
 2876         }
 2877 }
 2878 
 2879 /*
 2880  * Show details about the given vnode.
 2881  */
 2882 DB_SHOW_COMMAND(vnode, db_show_vnode)
 2883 {
 2884         struct vnode *vp;
 2885 
 2886         if (!have_addr)
 2887                 return;
 2888         vp = (struct vnode *)addr;
 2889         vn_printf(vp, "vnode ");
 2890 }
 2891 
 2892 /*
 2893  * Show details about the given mount point.
 2894  */
 2895 DB_SHOW_COMMAND(mount, db_show_mount)
 2896 {
 2897         struct mount *mp;
 2898         struct vfsopt *opt;
 2899         struct statfs *sp;
 2900         struct vnode *vp;
 2901         char buf[512];
 2902         u_int flags;
 2903 
 2904         if (!have_addr) {
 2905                 /* No address given, print short info about all mount points. */
 2906                 TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 2907                         db_printf("%p %s on %s (%s)\n", mp,
 2908                             mp->mnt_stat.f_mntfromname,
 2909                             mp->mnt_stat.f_mntonname,
 2910                             mp->mnt_stat.f_fstypename);
 2911                         if (db_pager_quit)
 2912                                 break;
 2913                 }
 2914                 db_printf("\nMore info: show mount <addr>\n");
 2915                 return;
 2916         }
 2917 
 2918         mp = (struct mount *)addr;
 2919         db_printf("%p %s on %s (%s)\n", mp, mp->mnt_stat.f_mntfromname,
 2920             mp->mnt_stat.f_mntonname, mp->mnt_stat.f_fstypename);
 2921 
 2922         buf[0] = '\0';
 2923         flags = mp->mnt_flag;
 2924 #define MNT_FLAG(flag)  do {                                            \
 2925         if (flags & (flag)) {                                           \
 2926                 if (buf[0] != '\0')                                     \
 2927                         strlcat(buf, ", ", sizeof(buf));                \
 2928                 strlcat(buf, (#flag) + 4, sizeof(buf));                 \
 2929                 flags &= ~(flag);                                       \
 2930         }                                                               \
 2931 } while (0)
 2932         MNT_FLAG(MNT_RDONLY);
 2933         MNT_FLAG(MNT_SYNCHRONOUS);
 2934         MNT_FLAG(MNT_NOEXEC);
 2935         MNT_FLAG(MNT_NOSUID);
 2936         MNT_FLAG(MNT_UNION);
 2937         MNT_FLAG(MNT_ASYNC);
 2938         MNT_FLAG(MNT_SUIDDIR);
 2939         MNT_FLAG(MNT_SOFTDEP);
 2940         MNT_FLAG(MNT_NOSYMFOLLOW);
 2941         MNT_FLAG(MNT_GJOURNAL);
 2942         MNT_FLAG(MNT_MULTILABEL);
 2943         MNT_FLAG(MNT_ACLS);
 2944         MNT_FLAG(MNT_NOATIME);
 2945         MNT_FLAG(MNT_NOCLUSTERR);
 2946         MNT_FLAG(MNT_NOCLUSTERW);
 2947         MNT_FLAG(MNT_NFS4ACLS);
 2948         MNT_FLAG(MNT_EXRDONLY);
 2949         MNT_FLAG(MNT_EXPORTED);
 2950         MNT_FLAG(MNT_DEFEXPORTED);
 2951         MNT_FLAG(MNT_EXPORTANON);
 2952         MNT_FLAG(MNT_EXKERB);
 2953         MNT_FLAG(MNT_EXPUBLIC);
 2954         MNT_FLAG(MNT_LOCAL);
 2955         MNT_FLAG(MNT_QUOTA);
 2956         MNT_FLAG(MNT_ROOTFS);
 2957         MNT_FLAG(MNT_USER);
 2958         MNT_FLAG(MNT_IGNORE);
 2959         MNT_FLAG(MNT_UPDATE);
 2960         MNT_FLAG(MNT_DELEXPORT);
 2961         MNT_FLAG(MNT_RELOAD);
 2962         MNT_FLAG(MNT_FORCE);
 2963         MNT_FLAG(MNT_SNAPSHOT);
 2964         MNT_FLAG(MNT_BYFSID);
 2965 #undef MNT_FLAG
 2966         if (flags != 0) {
 2967                 if (buf[0] != '\0')
 2968                         strlcat(buf, ", ", sizeof(buf));
 2969                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 2970                     "0x%08x", flags);
 2971         }
 2972         db_printf("    mnt_flag = %s\n", buf);
 2973 
 2974         buf[0] = '\0';
 2975         flags = mp->mnt_kern_flag;
 2976 #define MNT_KERN_FLAG(flag)     do {                                    \
 2977         if (flags & (flag)) {                                           \
 2978                 if (buf[0] != '\0')                                     \
 2979                         strlcat(buf, ", ", sizeof(buf));                \
 2980                 strlcat(buf, (#flag) + 5, sizeof(buf));                 \
 2981                 flags &= ~(flag);                                       \
 2982         }                                                               \
 2983 } while (0)
 2984         MNT_KERN_FLAG(MNTK_UNMOUNTF);
 2985         MNT_KERN_FLAG(MNTK_ASYNC);
 2986         MNT_KERN_FLAG(MNTK_SOFTDEP);
 2987         MNT_KERN_FLAG(MNTK_NOINSMNTQ);
 2988         MNT_KERN_FLAG(MNTK_UNMOUNT);
 2989         MNT_KERN_FLAG(MNTK_MWAIT);
 2990         MNT_KERN_FLAG(MNTK_SUSPEND);
 2991         MNT_KERN_FLAG(MNTK_SUSPEND2);
 2992         MNT_KERN_FLAG(MNTK_SUSPENDED);
 2993         MNT_KERN_FLAG(MNTK_MPSAFE);
 2994         MNT_KERN_FLAG(MNTK_NOKNOTE);
 2995         MNT_KERN_FLAG(MNTK_LOOKUP_SHARED);
 2996 #undef MNT_KERN_FLAG
 2997         if (flags != 0) {
 2998                 if (buf[0] != '\0')
 2999                         strlcat(buf, ", ", sizeof(buf));
 3000                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 3001                     "0x%08x", flags);
 3002         }
 3003         db_printf("    mnt_kern_flag = %s\n", buf);
 3004 
 3005         db_printf("    mnt_opt = ");
 3006         opt = TAILQ_FIRST(mp->mnt_opt);
 3007         if (opt != NULL) {
 3008                 db_printf("%s", opt->name);
 3009                 opt = TAILQ_NEXT(opt, link);
 3010                 while (opt != NULL) {
 3011                         db_printf(", %s", opt->name);
 3012                         opt = TAILQ_NEXT(opt, link);
 3013                 }
 3014         }
 3015         db_printf("\n");
 3016 
 3017         sp = &mp->mnt_stat;
 3018         db_printf("    mnt_stat = { version=%u type=%u flags=0x%016jx "
 3019             "bsize=%ju iosize=%ju blocks=%ju bfree=%ju bavail=%jd files=%ju "
 3020             "ffree=%jd syncwrites=%ju asyncwrites=%ju syncreads=%ju "
 3021             "asyncreads=%ju namemax=%u owner=%u fsid=[%d, %d] }\n",
 3022             (u_int)sp->f_version, (u_int)sp->f_type, (uintmax_t)sp->f_flags,
 3023             (uintmax_t)sp->f_bsize, (uintmax_t)sp->f_iosize,
 3024             (uintmax_t)sp->f_blocks, (uintmax_t)sp->f_bfree,
 3025             (intmax_t)sp->f_bavail, (uintmax_t)sp->f_files,
 3026             (intmax_t)sp->f_ffree, (uintmax_t)sp->f_syncwrites,
 3027             (uintmax_t)sp->f_asyncwrites, (uintmax_t)sp->f_syncreads,
 3028             (uintmax_t)sp->f_asyncreads, (u_int)sp->f_namemax,
 3029             (u_int)sp->f_owner, (int)sp->f_fsid.val[0], (int)sp->f_fsid.val[1]);
 3030 
 3031         db_printf("    mnt_cred = { uid=%u ruid=%u",
 3032             (u_int)mp->mnt_cred->cr_uid, (u_int)mp->mnt_cred->cr_ruid);
 3033         if (jailed(mp->mnt_cred))
 3034                 db_printf(", jail=%d", mp->mnt_cred->cr_prison->pr_id);
 3035         db_printf(" }\n");
 3036         db_printf("    mnt_ref = %d\n", mp->mnt_ref);
 3037         db_printf("    mnt_gen = %d\n", mp->mnt_gen);
 3038         db_printf("    mnt_nvnodelistsize = %d\n", mp->mnt_nvnodelistsize);
 3039         db_printf("    mnt_writeopcount = %d\n", mp->mnt_writeopcount);
 3040         db_printf("    mnt_noasync = %u\n", mp->mnt_noasync);
 3041         db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
 3042         db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
 3043         db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
 3044         db_printf("    mnt_secondary_writes = %d\n", mp->mnt_secondary_writes);
 3045         db_printf("    mnt_secondary_accwrites = %d\n",
 3046             mp->mnt_secondary_accwrites);
 3047         db_printf("    mnt_gjprovider = %s\n",
 3048             mp->mnt_gjprovider != NULL ? mp->mnt_gjprovider : "NULL");
 3049         db_printf("\n");
 3050 
 3051         TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3052                 if (vp->v_type != VMARKER) {
 3053                         vn_printf(vp, "vnode ");
 3054                         if (db_pager_quit)
 3055                                 break;
 3056                 }
 3057         }
 3058 }
 3059 #endif  /* DDB */
 3060 
 3061 /*
 3062  * Fill in a struct xvfsconf based on a struct vfsconf.
 3063  */
 3064 static int
 3065 vfsconf2x(struct sysctl_req *req, struct vfsconf *vfsp)
 3066 {
 3067         struct xvfsconf xvfsp;
 3068 
 3069         bzero(&xvfsp, sizeof(xvfsp));
 3070         strcpy(xvfsp.vfc_name, vfsp->vfc_name);
 3071         xvfsp.vfc_typenum = vfsp->vfc_typenum;
 3072         xvfsp.vfc_refcount = vfsp->vfc_refcount;
 3073         xvfsp.vfc_flags = vfsp->vfc_flags;
 3074         /*
 3075          * These are unused in userland, we keep them
 3076          * to not break binary compatibility.
 3077          */
 3078         xvfsp.vfc_vfsops = NULL;
 3079         xvfsp.vfc_next = NULL;
 3080         return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 3081 }
 3082 
 3083 #ifdef COMPAT_FREEBSD32
 3084 struct xvfsconf32 {
 3085         uint32_t        vfc_vfsops;
 3086         char            vfc_name[MFSNAMELEN];
 3087         int32_t         vfc_typenum;
 3088         int32_t         vfc_refcount;
 3089         int32_t         vfc_flags;
 3090         uint32_t        vfc_next;
 3091 };
 3092 
 3093 static int
 3094 vfsconf2x32(struct sysctl_req *req, struct vfsconf *vfsp)
 3095 {
 3096         struct xvfsconf32 xvfsp;
 3097 
 3098         strcpy(xvfsp.vfc_name, vfsp->vfc_name);
 3099         xvfsp.vfc_typenum = vfsp->vfc_typenum;
 3100         xvfsp.vfc_refcount = vfsp->vfc_refcount;
 3101         xvfsp.vfc_flags = vfsp->vfc_flags;
 3102         xvfsp.vfc_vfsops = 0;
 3103         xvfsp.vfc_next = 0;
 3104         return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 3105 }
 3106 #endif
 3107 
 3108 /*
 3109  * Top level filesystem related information gathering.
 3110  */
 3111 static int
 3112 sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
 3113 {
 3114         struct vfsconf *vfsp;
 3115         int error;
 3116 
 3117         error = 0;
 3118         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3119 #ifdef COMPAT_FREEBSD32
 3120                 if (req->flags & SCTL_MASK32)
 3121                         error = vfsconf2x32(req, vfsp);
 3122                 else
 3123 #endif
 3124                         error = vfsconf2x(req, vfsp);
 3125                 if (error)
 3126                         break;
 3127         }
 3128         return (error);
 3129 }
 3130 
 3131 SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
 3132     "S,xvfsconf", "List of all configured filesystems");
 3133 
 3134 #ifndef BURN_BRIDGES
 3135 static int      sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
 3136 
 3137 static int
 3138 vfs_sysctl(SYSCTL_HANDLER_ARGS)
 3139 {
 3140         int *name = (int *)arg1 - 1;    /* XXX */
 3141         u_int namelen = arg2 + 1;       /* XXX */
 3142         struct vfsconf *vfsp;
 3143 
 3144         printf("WARNING: userland calling deprecated sysctl, "
 3145             "please rebuild world\n");
 3146 
 3147 #if 1 || defined(COMPAT_PRELITE2)
 3148         /* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
 3149         if (namelen == 1)
 3150                 return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
 3151 #endif
 3152 
 3153         switch (name[1]) {
 3154         case VFS_MAXTYPENUM:
 3155                 if (namelen != 2)
 3156                         return (ENOTDIR);
 3157                 return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
 3158         case VFS_CONF:
 3159                 if (namelen != 3)
 3160                         return (ENOTDIR);       /* overloaded */
 3161                 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
 3162                         if (vfsp->vfc_typenum == name[2])
 3163                                 break;
 3164                 if (vfsp == NULL)
 3165                         return (EOPNOTSUPP);
 3166 #ifdef COMPAT_FREEBSD32
 3167                 if (req->flags & SCTL_MASK32)
 3168                         return (vfsconf2x32(req, vfsp));
 3169                 else
 3170 #endif
 3171                         return (vfsconf2x(req, vfsp));
 3172         }
 3173         return (EOPNOTSUPP);
 3174 }
 3175 
 3176 static SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP,
 3177     vfs_sysctl, "Generic filesystem");
 3178 
 3179 #if 1 || defined(COMPAT_PRELITE2)
 3180 
 3181 static int
 3182 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
 3183 {
 3184         int error;
 3185         struct vfsconf *vfsp;
 3186         struct ovfsconf ovfs;
 3187 
 3188         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3189                 bzero(&ovfs, sizeof(ovfs));
 3190                 ovfs.vfc_vfsops = vfsp->vfc_vfsops;     /* XXX used as flag */
 3191                 strcpy(ovfs.vfc_name, vfsp->vfc_name);
 3192                 ovfs.vfc_index = vfsp->vfc_typenum;
 3193                 ovfs.vfc_refcount = vfsp->vfc_refcount;
 3194                 ovfs.vfc_flags = vfsp->vfc_flags;
 3195                 error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
 3196                 if (error)
 3197                         return error;
 3198         }
 3199         return 0;
 3200 }
 3201 
 3202 #endif /* 1 || COMPAT_PRELITE2 */
 3203 #endif /* !BURN_BRIDGES */
 3204 
 3205 #define KINFO_VNODESLOP         10
 3206 #ifdef notyet
 3207 /*
 3208  * Dump vnode list (via sysctl).
 3209  */
 3210 /* ARGSUSED */
 3211 static int
 3212 sysctl_vnode(SYSCTL_HANDLER_ARGS)
 3213 {
 3214         struct xvnode *xvn;
 3215         struct mount *mp;
 3216         struct vnode *vp;
 3217         int error, len, n;
 3218 
 3219         /*
 3220          * Stale numvnodes access is not fatal here.
 3221          */
 3222         req->lock = 0;
 3223         len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
 3224         if (!req->oldptr)
 3225                 /* Make an estimate */
 3226                 return (SYSCTL_OUT(req, 0, len));
 3227 
 3228         error = sysctl_wire_old_buffer(req, 0);
 3229         if (error != 0)
 3230                 return (error);
 3231         xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
 3232         n = 0;
 3233         mtx_lock(&mountlist_mtx);
 3234         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 3235                 if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
 3236                         continue;
 3237                 MNT_ILOCK(mp);
 3238                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3239                         if (n == len)
 3240                                 break;
 3241                         vref(vp);
 3242                         xvn[n].xv_size = sizeof *xvn;
 3243                         xvn[n].xv_vnode = vp;
 3244                         xvn[n].xv_id = 0;       /* XXX compat */
 3245 #define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
 3246                         XV_COPY(usecount);
 3247                         XV_COPY(writecount);
 3248                         XV_COPY(holdcnt);
 3249                         XV_COPY(mount);
 3250                         XV_COPY(numoutput);
 3251                         XV_COPY(type);
 3252 #undef XV_COPY
 3253                         xvn[n].xv_flag = vp->v_vflag;
 3254 
 3255                         switch (vp->v_type) {
 3256                         case VREG:
 3257                         case VDIR:
 3258                         case VLNK:
 3259                                 break;
 3260                         case VBLK:
 3261                         case VCHR:
 3262                                 if (vp->v_rdev == NULL) {
 3263                                         vrele(vp);
 3264                                         continue;
 3265                                 }
 3266                                 xvn[n].xv_dev = dev2udev(vp->v_rdev);
 3267                                 break;
 3268                         case VSOCK:
 3269                                 xvn[n].xv_socket = vp->v_socket;
 3270                                 break;
 3271                         case VFIFO:
 3272                                 xvn[n].xv_fifo = vp->v_fifoinfo;
 3273                                 break;
 3274                         case VNON:
 3275                         case VBAD:
 3276                         default:
 3277                                 /* shouldn't happen? */
 3278                                 vrele(vp);
 3279                                 continue;
 3280                         }
 3281                         vrele(vp);
 3282                         ++n;
 3283                 }
 3284                 MNT_IUNLOCK(mp);
 3285                 mtx_lock(&mountlist_mtx);
 3286                 vfs_unbusy(mp);
 3287                 if (n == len)
 3288                         break;
 3289         }
 3290         mtx_unlock(&mountlist_mtx);
 3291 
 3292         error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
 3293         free(xvn, M_TEMP);
 3294         return (error);
 3295 }
 3296 
 3297 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
 3298     0, 0, sysctl_vnode, "S,xvnode", "");
 3299 #endif
 3300 
 3301 /*
 3302  * Unmount all filesystems. The list is traversed in reverse order
 3303  * of mounting to avoid dependencies.
 3304  */
 3305 void
 3306 vfs_unmountall(void)
 3307 {
 3308         struct mount *mp;
 3309         struct thread *td;
 3310         int error;
 3311 
 3312         KASSERT(curthread != NULL, ("vfs_unmountall: NULL curthread"));
 3313         CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__);
 3314         td = curthread;
 3315 
 3316         /*
 3317          * Since this only runs when rebooting, it is not interlocked.
 3318          */
 3319         while(!TAILQ_EMPTY(&mountlist)) {
 3320                 mp = TAILQ_LAST(&mountlist, mntlist);
 3321                 error = dounmount(mp, MNT_FORCE, td);
 3322                 if (error) {
 3323                         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 3324                         /*
 3325                          * XXX: Due to the way in which we mount the root
 3326                          * file system off of devfs, devfs will generate a
 3327                          * "busy" warning when we try to unmount it before
 3328                          * the root.  Don't print a warning as a result in
 3329                          * order to avoid false positive errors that may
 3330                          * cause needless upset.
 3331                          */
 3332                         if (strcmp(mp->mnt_vfc->vfc_name, "devfs") != 0) {
 3333                                 printf("unmount of %s failed (",
 3334                                     mp->mnt_stat.f_mntonname);
 3335                                 if (error == EBUSY)
 3336                                         printf("BUSY)\n");
 3337                                 else
 3338                                         printf("%d)\n", error);
 3339                         }
 3340                 } else {
 3341                         /* The unmount has removed mp from the mountlist */
 3342                 }
 3343         }
 3344 }
 3345 
 3346 /*
 3347  * perform msync on all vnodes under a mount point
 3348  * the mount point must be locked.
 3349  */
 3350 void
 3351 vfs_msync(struct mount *mp, int flags)
 3352 {
 3353         struct vnode *vp, *mvp;
 3354         struct vm_object *obj;
 3355 
 3356         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
 3357         MNT_ILOCK(mp);
 3358         MNT_VNODE_FOREACH(vp, mp, mvp) {
 3359                 VI_LOCK(vp);
 3360                 obj = vp->v_object;
 3361                 if (obj != NULL && (obj->flags & OBJ_MIGHTBEDIRTY) != 0 &&
 3362                     (flags == MNT_WAIT || VOP_ISLOCKED(vp) == 0)) {
 3363                         MNT_IUNLOCK(mp);
 3364                         if (!vget(vp,
 3365                             LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
 3366                             curthread)) {
 3367                                 if (vp->v_vflag & VV_NOSYNC) {  /* unlinked */
 3368                                         vput(vp);
 3369                                         MNT_ILOCK(mp);
 3370                                         continue;
 3371                                 }
 3372 
 3373                                 obj = vp->v_object;
 3374                                 if (obj != NULL) {
 3375                                         VM_OBJECT_LOCK(obj);
 3376                                         vm_object_page_clean(obj, 0, 0,
 3377                                             flags == MNT_WAIT ?
 3378                                             OBJPC_SYNC : OBJPC_NOSYNC);
 3379                                         VM_OBJECT_UNLOCK(obj);
 3380                                 }
 3381                                 vput(vp);
 3382                         }
 3383                         MNT_ILOCK(mp);
 3384                 } else
 3385                         VI_UNLOCK(vp);
 3386         }
 3387         MNT_IUNLOCK(mp);
 3388 }
 3389 
 3390 /*
 3391  * Mark a vnode as free, putting it up for recycling.
 3392  */
 3393 static void
 3394 vfree(struct vnode *vp)
 3395 {
 3396 
 3397         ASSERT_VI_LOCKED(vp, "vfree");
 3398         mtx_lock(&vnode_free_list_mtx);
 3399         VNASSERT(vp->v_op != NULL, vp, ("vfree: vnode already reclaimed."));
 3400         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp, ("vnode already free"));
 3401         VNASSERT(VSHOULDFREE(vp), vp, ("vfree: freeing when we shouldn't"));
 3402         VNASSERT((vp->v_iflag & VI_DOOMED) == 0, vp,
 3403             ("vfree: Freeing doomed vnode"));
 3404         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3405         if (vp->v_iflag & VI_AGE) {
 3406                 TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
 3407         } else {
 3408                 TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 3409         }
 3410         freevnodes++;
 3411         vp->v_iflag &= ~VI_AGE;
 3412         vp->v_iflag |= VI_FREE;
 3413         mtx_unlock(&vnode_free_list_mtx);
 3414 }
 3415 
 3416 /*
 3417  * Opposite of vfree() - mark a vnode as in use.
 3418  */
 3419 static void
 3420 vbusy(struct vnode *vp)
 3421 {
 3422         ASSERT_VI_LOCKED(vp, "vbusy");
 3423         VNASSERT((vp->v_iflag & VI_FREE) != 0, vp, ("vnode not free"));
 3424         VNASSERT(vp->v_op != NULL, vp, ("vbusy: vnode already reclaimed."));
 3425         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3426 
 3427         mtx_lock(&vnode_free_list_mtx);
 3428         TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
 3429         freevnodes--;
 3430         vp->v_iflag &= ~(VI_FREE|VI_AGE);
 3431         mtx_unlock(&vnode_free_list_mtx);
 3432 }
 3433 
 3434 static void
 3435 destroy_vpollinfo(struct vpollinfo *vi)
 3436 {
 3437         seldrain(&vi->vpi_selinfo);
 3438         knlist_destroy(&vi->vpi_selinfo.si_note);
 3439         mtx_destroy(&vi->vpi_lock);
 3440         uma_zfree(vnodepoll_zone, vi);
 3441 }
 3442 
 3443 /*
 3444  * Initalize per-vnode helper structure to hold poll-related state.
 3445  */
 3446 void
 3447 v_addpollinfo(struct vnode *vp)
 3448 {
 3449         struct vpollinfo *vi;
 3450 
 3451         if (vp->v_pollinfo != NULL)
 3452                 return;
 3453         vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
 3454         mtx_init(&vi->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
 3455         knlist_init(&vi->vpi_selinfo.si_note, vp, vfs_knllock,
 3456             vfs_knlunlock, vfs_knl_assert_locked, vfs_knl_assert_unlocked);
 3457         VI_LOCK(vp);
 3458         if (vp->v_pollinfo != NULL) {
 3459                 VI_UNLOCK(vp);
 3460                 destroy_vpollinfo(vi);
 3461                 return;
 3462         }
 3463         vp->v_pollinfo = vi;
 3464         VI_UNLOCK(vp);
 3465 }
 3466 
 3467 /*
 3468  * Record a process's interest in events which might happen to
 3469  * a vnode.  Because poll uses the historic select-style interface
 3470  * internally, this routine serves as both the ``check for any
 3471  * pending events'' and the ``record my interest in future events''
 3472  * functions.  (These are done together, while the lock is held,
 3473  * to avoid race conditions.)
 3474  */
 3475 int
 3476 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
 3477 {
 3478 
 3479         v_addpollinfo(vp);
 3480         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3481         if (vp->v_pollinfo->vpi_revents & events) {
 3482                 /*
 3483                  * This leaves events we are not interested
 3484                  * in available for the other process which
 3485                  * which presumably had requested them
 3486                  * (otherwise they would never have been
 3487                  * recorded).
 3488                  */
 3489                 events &= vp->v_pollinfo->vpi_revents;
 3490                 vp->v_pollinfo->vpi_revents &= ~events;
 3491 
 3492                 mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3493                 return (events);
 3494         }
 3495         vp->v_pollinfo->vpi_events |= events;
 3496         selrecord(td, &vp->v_pollinfo->vpi_selinfo);
 3497         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3498         return (0);
 3499 }
 3500 
 3501 /*
 3502  * Routine to create and manage a filesystem syncer vnode.
 3503  */
 3504 #define sync_close ((int (*)(struct  vop_close_args *))nullop)
 3505 static int      sync_fsync(struct  vop_fsync_args *);
 3506 static int      sync_inactive(struct  vop_inactive_args *);
 3507 static int      sync_reclaim(struct  vop_reclaim_args *);
 3508 
 3509 static struct vop_vector sync_vnodeops = {
 3510         .vop_bypass =   VOP_EOPNOTSUPP,
 3511         .vop_close =    sync_close,             /* close */
 3512         .vop_fsync =    sync_fsync,             /* fsync */
 3513         .vop_inactive = sync_inactive,  /* inactive */
 3514         .vop_reclaim =  sync_reclaim,   /* reclaim */
 3515         .vop_lock1 =    vop_stdlock,    /* lock */
 3516         .vop_unlock =   vop_stdunlock,  /* unlock */
 3517         .vop_islocked = vop_stdislocked,        /* islocked */
 3518 };
 3519 
 3520 /*
 3521  * Create a new filesystem syncer vnode for the specified mount point.
 3522  */
 3523 int
 3524 vfs_allocate_syncvnode(struct mount *mp)
 3525 {
 3526         struct vnode *vp;
 3527         struct bufobj *bo;
 3528         static long start, incr, next;
 3529         int error;
 3530 
 3531         /* Allocate a new vnode */
 3532         if ((error = getnewvnode("syncer", mp, &sync_vnodeops, &vp)) != 0) {
 3533                 mp->mnt_syncer = NULL;
 3534                 return (error);
 3535         }
 3536         vp->v_type = VNON;
 3537         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3538         vp->v_vflag |= VV_FORCEINSMQ;
 3539         error = insmntque(vp, mp);
 3540         if (error != 0)
 3541                 panic("vfs_allocate_syncvnode: insmntque failed");
 3542         vp->v_vflag &= ~VV_FORCEINSMQ;
 3543         VOP_UNLOCK(vp, 0);
 3544         /*
 3545          * Place the vnode onto the syncer worklist. We attempt to
 3546          * scatter them about on the list so that they will go off
 3547          * at evenly distributed times even if all the filesystems
 3548          * are mounted at once.
 3549          */
 3550         next += incr;
 3551         if (next == 0 || next > syncer_maxdelay) {
 3552                 start /= 2;
 3553                 incr /= 2;
 3554                 if (start == 0) {
 3555                         start = syncer_maxdelay / 2;
 3556                         incr = syncer_maxdelay;
 3557                 }
 3558                 next = start;
 3559         }
 3560         bo = &vp->v_bufobj;
 3561         BO_LOCK(bo);
 3562         vn_syncer_add_to_worklist(bo, syncdelay > 0 ? next % syncdelay : 0);
 3563         /* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
 3564         mtx_lock(&sync_mtx);
 3565         sync_vnode_count++;
 3566         mtx_unlock(&sync_mtx);
 3567         BO_UNLOCK(bo);
 3568         mp->mnt_syncer = vp;
 3569         return (0);
 3570 }
 3571 
 3572 /*
 3573  * Do a lazy sync of the filesystem.
 3574  */
 3575 static int
 3576 sync_fsync(struct vop_fsync_args *ap)
 3577 {
 3578         struct vnode *syncvp = ap->a_vp;
 3579         struct mount *mp = syncvp->v_mount;
 3580         int error, save;
 3581         struct bufobj *bo;
 3582 
 3583         /*
 3584          * We only need to do something if this is a lazy evaluation.
 3585          */
 3586         if (ap->a_waitfor != MNT_LAZY)
 3587                 return (0);
 3588 
 3589         /*
 3590          * Move ourselves to the back of the sync list.
 3591          */
 3592         bo = &syncvp->v_bufobj;
 3593         BO_LOCK(bo);
 3594         vn_syncer_add_to_worklist(bo, syncdelay);
 3595         BO_UNLOCK(bo);
 3596 
 3597         /*
 3598          * Walk the list of vnodes pushing all that are dirty and
 3599          * not already on the sync list.
 3600          */
 3601         mtx_lock(&mountlist_mtx);
 3602         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK) != 0) {
 3603                 mtx_unlock(&mountlist_mtx);
 3604                 return (0);
 3605         }
 3606         if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
 3607                 vfs_unbusy(mp);
 3608                 return (0);
 3609         }
 3610         save = curthread_pflags_set(TDP_SYNCIO);
 3611         vfs_msync(mp, MNT_NOWAIT);
 3612         error = VFS_SYNC(mp, MNT_LAZY);
 3613         curthread_pflags_restore(save);
 3614         vn_finished_write(mp);
 3615         vfs_unbusy(mp);
 3616         return (error);
 3617 }
 3618 
 3619 /*
 3620  * The syncer vnode is no referenced.
 3621  */
 3622 static int
 3623 sync_inactive(struct vop_inactive_args *ap)
 3624 {
 3625 
 3626         vgone(ap->a_vp);
 3627         return (0);
 3628 }
 3629 
 3630 /*
 3631  * The syncer vnode is no longer needed and is being decommissioned.
 3632  *
 3633  * Modifications to the worklist must be protected by sync_mtx.
 3634  */
 3635 static int
 3636 sync_reclaim(struct vop_reclaim_args *ap)
 3637 {
 3638         struct vnode *vp = ap->a_vp;
 3639         struct bufobj *bo;
 3640 
 3641         bo = &vp->v_bufobj;
 3642         BO_LOCK(bo);
 3643         vp->v_mount->mnt_syncer = NULL;
 3644         if (bo->bo_flag & BO_ONWORKLST) {
 3645                 mtx_lock(&sync_mtx);
 3646                 LIST_REMOVE(bo, bo_synclist);
 3647                 syncer_worklist_len--;
 3648                 sync_vnode_count--;
 3649                 mtx_unlock(&sync_mtx);
 3650                 bo->bo_flag &= ~BO_ONWORKLST;
 3651         }
 3652         BO_UNLOCK(bo);
 3653 
 3654         return (0);
 3655 }
 3656 
 3657 /*
 3658  * Check if vnode represents a disk device
 3659  */
 3660 int
 3661 vn_isdisk(struct vnode *vp, int *errp)
 3662 {
 3663         int error;
 3664 
 3665         error = 0;
 3666         dev_lock();
 3667         if (vp->v_type != VCHR)
 3668                 error = ENOTBLK;
 3669         else if (vp->v_rdev == NULL)
 3670                 error = ENXIO;
 3671         else if (vp->v_rdev->si_devsw == NULL)
 3672                 error = ENXIO;
 3673         else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
 3674                 error = ENOTBLK;
 3675         dev_unlock();
 3676         if (errp != NULL)
 3677                 *errp = error;
 3678         return (error == 0);
 3679 }
 3680 
 3681 /*
 3682  * Common filesystem object access control check routine.  Accepts a
 3683  * vnode's type, "mode", uid and gid, requested access mode, credentials,
 3684  * and optional call-by-reference privused argument allowing vaccess()
 3685  * to indicate to the caller whether privilege was used to satisfy the
 3686  * request (obsoleted).  Returns 0 on success, or an errno on failure.
 3687  */
 3688 int
 3689 vaccess(enum vtype type, mode_t file_mode, uid_t file_uid, gid_t file_gid,
 3690     accmode_t accmode, struct ucred *cred, int *privused)
 3691 {
 3692         accmode_t dac_granted;
 3693         accmode_t priv_granted;
 3694 
 3695         KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND)) == 0,
 3696             ("invalid bit in accmode"));
 3697 
 3698         /*
 3699          * Look for a normal, non-privileged way to access the file/directory
 3700          * as requested.  If it exists, go with that.
 3701          */
 3702 
 3703         if (privused != NULL)
 3704                 *privused = 0;
 3705 
 3706         dac_granted = 0;
 3707 
 3708         /* Check the owner. */
 3709         if (cred->cr_uid == file_uid) {
 3710                 dac_granted |= VADMIN;
 3711                 if (file_mode & S_IXUSR)
 3712                         dac_granted |= VEXEC;
 3713                 if (file_mode & S_IRUSR)
 3714                         dac_granted |= VREAD;
 3715                 if (file_mode & S_IWUSR)
 3716                         dac_granted |= (VWRITE | VAPPEND);
 3717 
 3718                 if ((accmode & dac_granted) == accmode)
 3719                         return (0);
 3720 
 3721                 goto privcheck;
 3722         }
 3723 
 3724         /* Otherwise, check the groups (first match) */
 3725         if (groupmember(file_gid, cred)) {
 3726                 if (file_mode & S_IXGRP)
 3727                         dac_granted |= VEXEC;
 3728                 if (file_mode & S_IRGRP)
 3729                         dac_granted |= VREAD;
 3730                 if (file_mode & S_IWGRP)
 3731                         dac_granted |= (VWRITE | VAPPEND);
 3732 
 3733                 if ((accmode & dac_granted) == accmode)
 3734                         return (0);
 3735 
 3736                 goto privcheck;
 3737         }
 3738 
 3739         /* Otherwise, check everyone else. */
 3740         if (file_mode & S_IXOTH)
 3741                 dac_granted |= VEXEC;
 3742         if (file_mode & S_IROTH)
 3743                 dac_granted |= VREAD;
 3744         if (file_mode & S_IWOTH)
 3745                 dac_granted |= (VWRITE | VAPPEND);
 3746         if ((accmode & dac_granted) == accmode)
 3747                 return (0);
 3748 
 3749 privcheck:
 3750         /*
 3751          * Build a privilege mask to determine if the set of privileges
 3752          * satisfies the requirements when combined with the granted mask
 3753          * from above.  For each privilege, if the privilege is required,
 3754          * bitwise or the request type onto the priv_granted mask.
 3755          */
 3756         priv_granted = 0;
 3757 
 3758         if (type == VDIR) {
 3759                 /*
 3760                  * For directories, use PRIV_VFS_LOOKUP to satisfy VEXEC
 3761                  * requests, instead of PRIV_VFS_EXEC.
 3762                  */
 3763                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3764                     !priv_check_cred(cred, PRIV_VFS_LOOKUP, 0))
 3765                         priv_granted |= VEXEC;
 3766         } else {
 3767                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3768                     !priv_check_cred(cred, PRIV_VFS_EXEC, 0))
 3769                         priv_granted |= VEXEC;
 3770         }
 3771 
 3772         if ((accmode & VREAD) && ((dac_granted & VREAD) == 0) &&
 3773             !priv_check_cred(cred, PRIV_VFS_READ, 0))
 3774                 priv_granted |= VREAD;
 3775 
 3776         if ((accmode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
 3777             !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
 3778                 priv_granted |= (VWRITE | VAPPEND);
 3779 
 3780         if ((accmode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
 3781             !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
 3782                 priv_granted |= VADMIN;
 3783 
 3784         if ((accmode & (priv_granted | dac_granted)) == accmode) {
 3785                 /* XXX audit: privilege used */
 3786                 if (privused != NULL)
 3787                         *privused = 1;
 3788                 return (0);
 3789         }
 3790 
 3791         return ((accmode & VADMIN) ? EPERM : EACCES);
 3792 }
 3793 
 3794 /*
 3795  * Credential check based on process requesting service, and per-attribute
 3796  * permissions.
 3797  */
 3798 int
 3799 extattr_check_cred(struct vnode *vp, int attrnamespace, struct ucred *cred,
 3800     struct thread *td, accmode_t accmode)
 3801 {
 3802 
 3803         /*
 3804          * Kernel-invoked always succeeds.
 3805          */
 3806         if (cred == NOCRED)
 3807                 return (0);
 3808 
 3809         /*
 3810          * Do not allow privileged processes in jail to directly manipulate
 3811          * system attributes.
 3812          */
 3813         switch (attrnamespace) {
 3814         case EXTATTR_NAMESPACE_SYSTEM:
 3815                 /* Potentially should be: return (EPERM); */
 3816                 return (priv_check_cred(cred, PRIV_VFS_EXTATTR_SYSTEM, 0));
 3817         case EXTATTR_NAMESPACE_USER:
 3818                 return (VOP_ACCESS(vp, accmode, cred, td));
 3819         default:
 3820                 return (EPERM);
 3821         }
 3822 }
 3823 
 3824 #ifdef DEBUG_VFS_LOCKS
 3825 /*
 3826  * This only exists to supress warnings from unlocked specfs accesses.  It is
 3827  * no longer ok to have an unlocked VFS.
 3828  */
 3829 #define IGNORE_LOCK(vp) (panicstr != NULL || (vp) == NULL ||            \
 3830         (vp)->v_type == VCHR || (vp)->v_type == VBAD)
 3831 
 3832 int vfs_badlock_ddb = 1;        /* Drop into debugger on violation. */
 3833 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0,
 3834     "Drop into debugger on lock violation");
 3835 
 3836 int vfs_badlock_mutex = 1;      /* Check for interlock across VOPs. */
 3837 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex,
 3838     0, "Check for interlock across VOPs");
 3839 
 3840 int vfs_badlock_print = 1;      /* Print lock violations. */
 3841 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print,
 3842     0, "Print lock violations");
 3843 
 3844 #ifdef KDB
 3845 int vfs_badlock_backtrace = 1;  /* Print backtrace at lock violations. */
 3846 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW,
 3847     &vfs_badlock_backtrace, 0, "Print backtrace at lock violations");
 3848 #endif
 3849 
 3850 static void
 3851 vfs_badlock(const char *msg, const char *str, struct vnode *vp)
 3852 {
 3853 
 3854 #ifdef KDB
 3855         if (vfs_badlock_backtrace)
 3856                 kdb_backtrace();
 3857 #endif
 3858         if (vfs_badlock_print)
 3859                 printf("%s: %p %s\n", str, (void *)vp, msg);
 3860         if (vfs_badlock_ddb)
 3861                 kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3862 }
 3863 
 3864 void
 3865 assert_vi_locked(struct vnode *vp, const char *str)
 3866 {
 3867 
 3868         if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
 3869                 vfs_badlock("interlock is not locked but should be", str, vp);
 3870 }
 3871 
 3872 void
 3873 assert_vi_unlocked(struct vnode *vp, const char *str)
 3874 {
 3875 
 3876         if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
 3877                 vfs_badlock("interlock is locked but should not be", str, vp);
 3878 }
 3879 
 3880 void
 3881 assert_vop_locked(struct vnode *vp, const char *str)
 3882 {
 3883         int locked;
 3884 
 3885         if (!IGNORE_LOCK(vp)) {
 3886                 locked = VOP_ISLOCKED(vp);
 3887                 if (locked == 0 || locked == LK_EXCLOTHER)
 3888                         vfs_badlock("is not locked but should be", str, vp);
 3889         }
 3890 }
 3891 
 3892 void
 3893 assert_vop_unlocked(struct vnode *vp, const char *str)
 3894 {
 3895 
 3896         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
 3897                 vfs_badlock("is locked but should not be", str, vp);
 3898 }
 3899 
 3900 void
 3901 assert_vop_elocked(struct vnode *vp, const char *str)
 3902 {
 3903 
 3904         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 3905                 vfs_badlock("is not exclusive locked but should be", str, vp);
 3906 }
 3907 
 3908 #if 0
 3909 void
 3910 assert_vop_elocked_other(struct vnode *vp, const char *str)
 3911 {
 3912 
 3913         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLOTHER)
 3914                 vfs_badlock("is not exclusive locked by another thread",
 3915                     str, vp);
 3916 }
 3917 
 3918 void
 3919 assert_vop_slocked(struct vnode *vp, const char *str)
 3920 {
 3921 
 3922         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_SHARED)
 3923                 vfs_badlock("is not locked shared but should be", str, vp);
 3924 }
 3925 #endif /* 0 */
 3926 #endif /* DEBUG_VFS_LOCKS */
 3927 
 3928 void
 3929 vop_rename_fail(struct vop_rename_args *ap)
 3930 {
 3931 
 3932         if (ap->a_tvp != NULL)
 3933                 vput(ap->a_tvp);
 3934         if (ap->a_tdvp == ap->a_tvp)
 3935                 vrele(ap->a_tdvp);
 3936         else
 3937                 vput(ap->a_tdvp);
 3938         vrele(ap->a_fdvp);
 3939         vrele(ap->a_fvp);
 3940 }
 3941 
 3942 void
 3943 vop_rename_pre(void *ap)
 3944 {
 3945         struct vop_rename_args *a = ap;
 3946 
 3947 #ifdef DEBUG_VFS_LOCKS
 3948         if (a->a_tvp)
 3949                 ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
 3950         ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
 3951         ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
 3952         ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
 3953 
 3954         /* Check the source (from). */
 3955         if (a->a_tdvp->v_vnlock != a->a_fdvp->v_vnlock &&
 3956             (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fdvp->v_vnlock))
 3957                 ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
 3958         if (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fvp->v_vnlock)
 3959                 ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: fvp locked");
 3960 
 3961         /* Check the target. */
 3962         if (a->a_tvp)
 3963                 ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
 3964         ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
 3965 #endif
 3966         if (a->a_tdvp != a->a_fdvp)
 3967                 vhold(a->a_fdvp);
 3968         if (a->a_tvp != a->a_fvp)
 3969                 vhold(a->a_fvp);
 3970         vhold(a->a_tdvp);
 3971         if (a->a_tvp)
 3972                 vhold(a->a_tvp);
 3973 }
 3974 
 3975 void
 3976 vop_strategy_pre(void *ap)
 3977 {
 3978 #ifdef DEBUG_VFS_LOCKS
 3979         struct vop_strategy_args *a;
 3980         struct buf *bp;
 3981 
 3982         a = ap;
 3983         bp = a->a_bp;
 3984 
 3985         /*
 3986          * Cluster ops lock their component buffers but not the IO container.
 3987          */
 3988         if ((bp->b_flags & B_CLUSTER) != 0)
 3989                 return;
 3990 
 3991         if (panicstr == NULL && !BUF_ISLOCKED(bp)) {
 3992                 if (vfs_badlock_print)
 3993                         printf(
 3994                             "VOP_STRATEGY: bp is not locked but should be\n");
 3995                 if (vfs_badlock_ddb)
 3996                         kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3997         }
 3998 #endif
 3999 }
 4000 
 4001 void
 4002 vop_lock_pre(void *ap)
 4003 {
 4004 #ifdef DEBUG_VFS_LOCKS
 4005         struct vop_lock1_args *a = ap;
 4006 
 4007         if ((a->a_flags & LK_INTERLOCK) == 0)
 4008                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 4009         else
 4010                 ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
 4011 #endif
 4012 }
 4013 
 4014 void
 4015 vop_lock_post(void *ap, int rc)
 4016 {
 4017 #ifdef DEBUG_VFS_LOCKS
 4018         struct vop_lock1_args *a = ap;
 4019 
 4020         ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 4021         if (rc == 0)
 4022                 ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
 4023 #endif
 4024 }
 4025 
 4026 void
 4027 vop_unlock_pre(void *ap)
 4028 {
 4029 #ifdef DEBUG_VFS_LOCKS
 4030         struct vop_unlock_args *a = ap;
 4031 
 4032         if (a->a_flags & LK_INTERLOCK)
 4033                 ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
 4034         ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
 4035 #endif
 4036 }
 4037 
 4038 void
 4039 vop_unlock_post(void *ap, int rc)
 4040 {
 4041 #ifdef DEBUG_VFS_LOCKS
 4042         struct vop_unlock_args *a = ap;
 4043 
 4044         if (a->a_flags & LK_INTERLOCK)
 4045                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
 4046 #endif
 4047 }
 4048 
 4049 void
 4050 vop_create_post(void *ap, int rc)
 4051 {
 4052         struct vop_create_args *a = ap;
 4053 
 4054         if (!rc)
 4055                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4056 }
 4057 
 4058 void
 4059 vop_deleteextattr_post(void *ap, int rc)
 4060 {
 4061         struct vop_deleteextattr_args *a = ap;
 4062 
 4063         if (!rc)
 4064                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4065 }
 4066 
 4067 void
 4068 vop_link_post(void *ap, int rc)
 4069 {
 4070         struct vop_link_args *a = ap;
 4071 
 4072         if (!rc) {
 4073                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_LINK);
 4074                 VFS_KNOTE_LOCKED(a->a_tdvp, NOTE_WRITE);
 4075         }
 4076 }
 4077 
 4078 void
 4079 vop_mkdir_post(void *ap, int rc)
 4080 {
 4081         struct vop_mkdir_args *a = ap;
 4082 
 4083         if (!rc)
 4084                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4085 }
 4086 
 4087 void
 4088 vop_mknod_post(void *ap, int rc)
 4089 {
 4090         struct vop_mknod_args *a = ap;
 4091 
 4092         if (!rc)
 4093                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4094 }
 4095 
 4096 void
 4097 vop_remove_post(void *ap, int rc)
 4098 {
 4099         struct vop_remove_args *a = ap;
 4100 
 4101         if (!rc) {
 4102                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4103                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4104         }
 4105 }
 4106 
 4107 void
 4108 vop_rename_post(void *ap, int rc)
 4109 {
 4110         struct vop_rename_args *a = ap;
 4111 
 4112         if (!rc) {
 4113                 VFS_KNOTE_UNLOCKED(a->a_fdvp, NOTE_WRITE);
 4114                 VFS_KNOTE_UNLOCKED(a->a_tdvp, NOTE_WRITE);
 4115                 VFS_KNOTE_UNLOCKED(a->a_fvp, NOTE_RENAME);
 4116                 if (a->a_tvp)
 4117                         VFS_KNOTE_UNLOCKED(a->a_tvp, NOTE_DELETE);
 4118         }
 4119         if (a->a_tdvp != a->a_fdvp)
 4120                 vdrop(a->a_fdvp);
 4121         if (a->a_tvp != a->a_fvp)
 4122                 vdrop(a->a_fvp);
 4123         vdrop(a->a_tdvp);
 4124         if (a->a_tvp)
 4125                 vdrop(a->a_tvp);
 4126 }
 4127 
 4128 void
 4129 vop_rmdir_post(void *ap, int rc)
 4130 {
 4131         struct vop_rmdir_args *a = ap;
 4132 
 4133         if (!rc) {
 4134                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4135                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4136         }
 4137 }
 4138 
 4139 void
 4140 vop_setattr_post(void *ap, int rc)
 4141 {
 4142         struct vop_setattr_args *a = ap;
 4143 
 4144         if (!rc)
 4145                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4146 }
 4147 
 4148 void
 4149 vop_setextattr_post(void *ap, int rc)
 4150 {
 4151         struct vop_setextattr_args *a = ap;
 4152 
 4153         if (!rc)
 4154                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4155 }
 4156 
 4157 void
 4158 vop_symlink_post(void *ap, int rc)
 4159 {
 4160         struct vop_symlink_args *a = ap;
 4161 
 4162         if (!rc)
 4163                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4164 }
 4165 
 4166 static struct knlist fs_knlist;
 4167 
 4168 static void
 4169 vfs_event_init(void *arg)
 4170 {
 4171         knlist_init_mtx(&fs_knlist, NULL);
 4172 }
 4173 /* XXX - correct order? */
 4174 SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
 4175 
 4176 void
 4177 vfs_event_signal(fsid_t *fsid, u_int32_t event, intptr_t data __unused)
 4178 {
 4179 
 4180         KNOTE_UNLOCKED(&fs_knlist, event);
 4181 }
 4182 
 4183 static int      filt_fsattach(struct knote *kn);
 4184 static void     filt_fsdetach(struct knote *kn);
 4185 static int      filt_fsevent(struct knote *kn, long hint);
 4186 
 4187 struct filterops fs_filtops =
 4188         { 0, filt_fsattach, filt_fsdetach, filt_fsevent };
 4189 
 4190 static int
 4191 filt_fsattach(struct knote *kn)
 4192 {
 4193 
 4194         kn->kn_flags |= EV_CLEAR;
 4195         knlist_add(&fs_knlist, kn, 0);
 4196         return (0);
 4197 }
 4198 
 4199 static void
 4200 filt_fsdetach(struct knote *kn)
 4201 {
 4202 
 4203         knlist_remove(&fs_knlist, kn, 0);
 4204 }
 4205 
 4206 static int
 4207 filt_fsevent(struct knote *kn, long hint)
 4208 {
 4209 
 4210         kn->kn_fflags |= hint;
 4211         return (kn->kn_fflags != 0);
 4212 }
 4213 
 4214 static int
 4215 sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
 4216 {
 4217         struct vfsidctl vc;
 4218         int error;
 4219         struct mount *mp;
 4220 
 4221         error = SYSCTL_IN(req, &vc, sizeof(vc));
 4222         if (error)
 4223                 return (error);
 4224         if (vc.vc_vers != VFS_CTL_VERS1)
 4225                 return (EINVAL);
 4226         mp = vfs_getvfs(&vc.vc_fsid);
 4227         if (mp == NULL)
 4228                 return (ENOENT);
 4229         /* ensure that a specific sysctl goes to the right filesystem. */
 4230         if (strcmp(vc.vc_fstypename, "*") != 0 &&
 4231             strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
 4232                 vfs_rel(mp);
 4233                 return (EINVAL);
 4234         }
 4235         VCTLTOREQ(&vc, req);
 4236         error = VFS_SYSCTL(mp, vc.vc_op, req);
 4237         vfs_rel(mp);
 4238         return (error);
 4239 }
 4240 
 4241 SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLFLAG_WR, NULL, 0, sysctl_vfs_ctl, "",
 4242     "Sysctl by fsid");
 4243 
 4244 /*
 4245  * Function to initialize a va_filerev field sensibly.
 4246  * XXX: Wouldn't a random number make a lot more sense ??
 4247  */
 4248 u_quad_t
 4249 init_va_filerev(void)
 4250 {
 4251         struct bintime bt;
 4252 
 4253         getbinuptime(&bt);
 4254         return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
 4255 }
 4256 
 4257 static int      filt_vfsread(struct knote *kn, long hint);
 4258 static int      filt_vfswrite(struct knote *kn, long hint);
 4259 static int      filt_vfsvnode(struct knote *kn, long hint);
 4260 static void     filt_vfsdetach(struct knote *kn);
 4261 static struct filterops vfsread_filtops =
 4262         { 1, NULL, filt_vfsdetach, filt_vfsread };
 4263 static struct filterops vfswrite_filtops =
 4264         { 1, NULL, filt_vfsdetach, filt_vfswrite };
 4265 static struct filterops vfsvnode_filtops =
 4266         { 1, NULL, filt_vfsdetach, filt_vfsvnode };
 4267 
 4268 static void
 4269 vfs_knllock(void *arg)
 4270 {
 4271         struct vnode *vp = arg;
 4272 
 4273         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 4274 }
 4275 
 4276 static void
 4277 vfs_knlunlock(void *arg)
 4278 {
 4279         struct vnode *vp = arg;
 4280 
 4281         VOP_UNLOCK(vp, 0);
 4282 }
 4283 
 4284 static void
 4285 vfs_knl_assert_locked(void *arg)
 4286 {
 4287 #ifdef DEBUG_VFS_LOCKS
 4288         struct vnode *vp = arg;
 4289 
 4290         ASSERT_VOP_LOCKED(vp, "vfs_knl_assert_locked");
 4291 #endif
 4292 }
 4293 
 4294 static void
 4295 vfs_knl_assert_unlocked(void *arg)
 4296 {
 4297 #ifdef DEBUG_VFS_LOCKS
 4298         struct vnode *vp = arg;
 4299 
 4300         ASSERT_VOP_UNLOCKED(vp, "vfs_knl_assert_unlocked");
 4301 #endif
 4302 }
 4303 
 4304 int
 4305 vfs_kqfilter(struct vop_kqfilter_args *ap)
 4306 {
 4307         struct vnode *vp = ap->a_vp;
 4308         struct knote *kn = ap->a_kn;
 4309         struct knlist *knl;
 4310 
 4311         switch (kn->kn_filter) {
 4312         case EVFILT_READ:
 4313                 kn->kn_fop = &vfsread_filtops;
 4314                 break;
 4315         case EVFILT_WRITE:
 4316                 kn->kn_fop = &vfswrite_filtops;
 4317                 break;
 4318         case EVFILT_VNODE:
 4319                 kn->kn_fop = &vfsvnode_filtops;
 4320                 break;
 4321         default:
 4322                 return (EINVAL);
 4323         }
 4324 
 4325         kn->kn_hook = (caddr_t)vp;
 4326 
 4327         v_addpollinfo(vp);
 4328         if (vp->v_pollinfo == NULL)
 4329                 return (ENOMEM);
 4330         knl = &vp->v_pollinfo->vpi_selinfo.si_note;
 4331         knlist_add(knl, kn, 0);
 4332 
 4333         return (0);
 4334 }
 4335 
 4336 /*
 4337  * Detach knote from vnode
 4338  */
 4339 static void
 4340 filt_vfsdetach(struct knote *kn)
 4341 {
 4342         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4343 
 4344         KASSERT(vp->v_pollinfo != NULL, ("Missing v_pollinfo"));
 4345         knlist_remove(&vp->v_pollinfo->vpi_selinfo.si_note, kn, 0);
 4346 }
 4347 
 4348 /*ARGSUSED*/
 4349 static int
 4350 filt_vfsread(struct knote *kn, long hint)
 4351 {
 4352         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4353         struct vattr va;
 4354         int res;
 4355 
 4356         /*
 4357          * filesystem is gone, so set the EOF flag and schedule
 4358          * the knote for deletion.
 4359          */
 4360         if (hint == NOTE_REVOKE) {
 4361                 VI_LOCK(vp);
 4362                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4363                 VI_UNLOCK(vp);
 4364                 return (1);
 4365         }
 4366 
 4367         if (VOP_GETATTR(vp, &va, curthread->td_ucred))
 4368                 return (0);
 4369 
 4370         VI_LOCK(vp);
 4371         kn->kn_data = va.va_size - kn->kn_fp->f_offset;
 4372         res = (kn->kn_data != 0);
 4373         VI_UNLOCK(vp);
 4374         return (res);
 4375 }
 4376 
 4377 /*ARGSUSED*/
 4378 static int
 4379 filt_vfswrite(struct knote *kn, long hint)
 4380 {
 4381         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4382 
 4383         VI_LOCK(vp);
 4384 
 4385         /*
 4386          * filesystem is gone, so set the EOF flag and schedule
 4387          * the knote for deletion.
 4388          */
 4389         if (hint == NOTE_REVOKE)
 4390                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4391 
 4392         kn->kn_data = 0;
 4393         VI_UNLOCK(vp);
 4394         return (1);
 4395 }
 4396 
 4397 static int
 4398 filt_vfsvnode(struct knote *kn, long hint)
 4399 {
 4400         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4401         int res;
 4402 
 4403         VI_LOCK(vp);
 4404         if (kn->kn_sfflags & hint)
 4405                 kn->kn_fflags |= hint;
 4406         if (hint == NOTE_REVOKE) {
 4407                 kn->kn_flags |= EV_EOF;
 4408                 VI_UNLOCK(vp);
 4409                 return (1);
 4410         }
 4411         res = (kn->kn_fflags != 0);
 4412         VI_UNLOCK(vp);
 4413         return (res);
 4414 }
 4415 
 4416 int
 4417 vfs_read_dirent(struct vop_readdir_args *ap, struct dirent *dp, off_t off)
 4418 {
 4419         int error;
 4420 
 4421         if (dp->d_reclen > ap->a_uio->uio_resid)
 4422                 return (ENAMETOOLONG);
 4423         error = uiomove(dp, dp->d_reclen, ap->a_uio);
 4424         if (error) {
 4425                 if (ap->a_ncookies != NULL) {
 4426                         if (ap->a_cookies != NULL)
 4427                                 free(ap->a_cookies, M_TEMP);
 4428                         ap->a_cookies = NULL;
 4429                         *ap->a_ncookies = 0;
 4430                 }
 4431                 return (error);
 4432         }
 4433         if (ap->a_ncookies == NULL)
 4434                 return (0);
 4435 
 4436         KASSERT(ap->a_cookies,
 4437             ("NULL ap->a_cookies value with non-NULL ap->a_ncookies!"));
 4438 
 4439         *ap->a_cookies = realloc(*ap->a_cookies,
 4440             (*ap->a_ncookies + 1) * sizeof(u_long), M_TEMP, M_WAITOK | M_ZERO);
 4441         (*ap->a_cookies)[*ap->a_ncookies] = off;
 4442         return (0);
 4443 }
 4444 
 4445 /*
 4446  * Mark for update the access time of the file if the filesystem
 4447  * supports VOP_MARKATIME.  This functionality is used by execve and
 4448  * mmap, so we want to avoid the I/O implied by directly setting
 4449  * va_atime for the sake of efficiency.
 4450  */
 4451 void
 4452 vfs_mark_atime(struct vnode *vp, struct ucred *cred)
 4453 {
 4454         struct mount *mp;
 4455 
 4456         mp = vp->v_mount;
 4457         VFS_ASSERT_GIANT(mp);
 4458         ASSERT_VOP_LOCKED(vp, "vfs_mark_atime");
 4459         if (mp != NULL && (mp->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0)
 4460                 (void)VOP_MARKATIME(vp);
 4461 }
 4462 
 4463 /*
 4464  * The purpose of this routine is to remove granularity from accmode_t,
 4465  * reducing it into standard unix access bits - VEXEC, VREAD, VWRITE,
 4466  * VADMIN and VAPPEND.
 4467  *
 4468  * If it returns 0, the caller is supposed to continue with the usual
 4469  * access checks using 'accmode' as modified by this routine.  If it
 4470  * returns nonzero value, the caller is supposed to return that value
 4471  * as errno.
 4472  *
 4473  * Note that after this routine runs, accmode may be zero.
 4474  */
 4475 int
 4476 vfs_unixify_accmode(accmode_t *accmode)
 4477 {
 4478         /*
 4479          * There is no way to specify explicit "deny" rule using
 4480          * file mode or POSIX.1e ACLs.
 4481          */
 4482         if (*accmode & VEXPLICIT_DENY) {
 4483                 *accmode = 0;
 4484                 return (0);
 4485         }
 4486 
 4487         /*
 4488          * None of these can be translated into usual access bits.
 4489          * Also, the common case for NFSv4 ACLs is to not contain
 4490          * either of these bits. Caller should check for VWRITE
 4491          * on the containing directory instead.
 4492          */
 4493         if (*accmode & (VDELETE_CHILD | VDELETE))
 4494                 return (EPERM);
 4495 
 4496         if (*accmode & VADMIN_PERMS) {
 4497                 *accmode &= ~VADMIN_PERMS;
 4498                 *accmode |= VADMIN;
 4499         }
 4500 
 4501         /*
 4502          * There is no way to deny VREAD_ATTRIBUTES, VREAD_ACL
 4503          * or VSYNCHRONIZE using file mode or POSIX.1e ACL.
 4504          */
 4505         *accmode &= ~(VSTAT_PERMS | VSYNCHRONIZE);
 4506 
 4507         return (0);
 4508 }

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