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/9.0/sys/kern/vfs_subr.c 226251 2011-10-11 13:22:35Z kib $");
   43 
   44 #include "opt_ddb.h"
   45 #include "opt_watchdog.h"
   46 
   47 #include <sys/param.h>
   48 #include <sys/systm.h>
   49 #include <sys/bio.h>
   50 #include <sys/buf.h>
   51 #include <sys/condvar.h>
   52 #include <sys/conf.h>
   53 #include <sys/dirent.h>
   54 #include <sys/event.h>
   55 #include <sys/eventhandler.h>
   56 #include <sys/extattr.h>
   57 #include <sys/file.h>
   58 #include <sys/fcntl.h>
   59 #include <sys/jail.h>
   60 #include <sys/kdb.h>
   61 #include <sys/kernel.h>
   62 #include <sys/kthread.h>
   63 #include <sys/lockf.h>
   64 #include <sys/malloc.h>
   65 #include <sys/mount.h>
   66 #include <sys/namei.h>
   67 #include <sys/priv.h>
   68 #include <sys/reboot.h>
   69 #include <sys/sched.h>
   70 #include <sys/sleepqueue.h>
   71 #include <sys/stat.h>
   72 #include <sys/sysctl.h>
   73 #include <sys/syslog.h>
   74 #include <sys/vmmeter.h>
   75 #include <sys/vnode.h>
   76 #ifdef SW_WATCHDOG
   77 #include <sys/watchdog.h>
   78 #endif
   79 
   80 #include <machine/stdarg.h>
   81 
   82 #include <security/mac/mac_framework.h>
   83 
   84 #include <vm/vm.h>
   85 #include <vm/vm_object.h>
   86 #include <vm/vm_extern.h>
   87 #include <vm/pmap.h>
   88 #include <vm/vm_map.h>
   89 #include <vm/vm_page.h>
   90 #include <vm/vm_kern.h>
   91 #include <vm/uma.h>
   92 
   93 #ifdef DDB
   94 #include <ddb/ddb.h>
   95 #endif
   96 
   97 #define WI_MPSAFEQ      0
   98 #define WI_GIANTQ       1
   99 
  100 static void     delmntque(struct vnode *vp);
  101 static int      flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo,
  102                     int slpflag, int slptimeo);
  103 static void     syncer_shutdown(void *arg, int howto);
  104 static int      vtryrecycle(struct vnode *vp);
  105 static void     vbusy(struct vnode *vp);
  106 static void     vinactive(struct vnode *, struct thread *);
  107 static void     v_incr_usecount(struct vnode *);
  108 static void     v_decr_usecount(struct vnode *);
  109 static void     v_decr_useonly(struct vnode *);
  110 static void     v_upgrade_usecount(struct vnode *);
  111 static void     vfree(struct vnode *);
  112 static void     vnlru_free(int);
  113 static void     vgonel(struct vnode *);
  114 static void     vfs_knllock(void *arg);
  115 static void     vfs_knlunlock(void *arg);
  116 static void     vfs_knl_assert_locked(void *arg);
  117 static void     vfs_knl_assert_unlocked(void *arg);
  118 static void     destroy_vpollinfo(struct vpollinfo *vi);
  119 
  120 /*
  121  * Number of vnodes in existence.  Increased whenever getnewvnode()
  122  * allocates a new vnode, decreased on vdestroy() called on VI_DOOMed
  123  * vnode.
  124  */
  125 static unsigned long    numvnodes;
  126 
  127 SYSCTL_ULONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
  128     "Number of vnodes in existence");
  129 
  130 /*
  131  * Conversion tables for conversion from vnode types to inode formats
  132  * and back.
  133  */
  134 enum vtype iftovt_tab[16] = {
  135         VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
  136         VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
  137 };
  138 int vttoif_tab[10] = {
  139         0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
  140         S_IFSOCK, S_IFIFO, S_IFMT, S_IFMT
  141 };
  142 
  143 /*
  144  * List of vnodes that are ready for recycling.
  145  */
  146 static TAILQ_HEAD(freelst, vnode) vnode_free_list;
  147 
  148 /*
  149  * Free vnode target.  Free vnodes may simply be files which have been stat'd
  150  * but not read.  This is somewhat common, and a small cache of such files
  151  * should be kept to avoid recreation costs.
  152  */
  153 static u_long wantfreevnodes;
  154 SYSCTL_ULONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
  155 /* Number of vnodes in the free list. */
  156 static u_long freevnodes;
  157 SYSCTL_ULONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0,
  158     "Number of vnodes in the free list");
  159 
  160 static int vlru_allow_cache_src;
  161 SYSCTL_INT(_vfs, OID_AUTO, vlru_allow_cache_src, CTLFLAG_RW,
  162     &vlru_allow_cache_src, 0, "Allow vlru to reclaim source vnode");
  163 
  164 /*
  165  * Various variables used for debugging the new implementation of
  166  * reassignbuf().
  167  * XXX these are probably of (very) limited utility now.
  168  */
  169 static int reassignbufcalls;
  170 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0,
  171     "Number of calls to reassignbuf");
  172 
  173 /*
  174  * Cache for the mount type id assigned to NFS.  This is used for
  175  * special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
  176  */
  177 int     nfs_mount_type = -1;
  178 
  179 /* To keep more than one thread at a time from running vfs_getnewfsid */
  180 static struct mtx mntid_mtx;
  181 
  182 /*
  183  * Lock for any access to the following:
  184  *      vnode_free_list
  185  *      numvnodes
  186  *      freevnodes
  187  */
  188 static struct mtx vnode_free_list_mtx;
  189 
  190 /* Publicly exported FS */
  191 struct nfs_public nfs_pub;
  192 
  193 /* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
  194 static uma_zone_t vnode_zone;
  195 static uma_zone_t vnodepoll_zone;
  196 
  197 /*
  198  * The workitem queue.
  199  *
  200  * It is useful to delay writes of file data and filesystem metadata
  201  * for tens of seconds so that quickly created and deleted files need
  202  * not waste disk bandwidth being created and removed. To realize this,
  203  * we append vnodes to a "workitem" queue. When running with a soft
  204  * updates implementation, most pending metadata dependencies should
  205  * not wait for more than a few seconds. Thus, mounted on block devices
  206  * are delayed only about a half the time that file data is delayed.
  207  * Similarly, directory updates are more critical, so are only delayed
  208  * about a third the time that file data is delayed. Thus, there are
  209  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
  210  * one each second (driven off the filesystem syncer process). The
  211  * syncer_delayno variable indicates the next queue that is to be processed.
  212  * Items that need to be processed soon are placed in this queue:
  213  *
  214  *      syncer_workitem_pending[syncer_delayno]
  215  *
  216  * A delay of fifteen seconds is done by placing the request fifteen
  217  * entries later in the queue:
  218  *
  219  *      syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
  220  *
  221  */
  222 static int syncer_delayno;
  223 static long syncer_mask;
  224 LIST_HEAD(synclist, bufobj);
  225 static struct synclist *syncer_workitem_pending[2];
  226 /*
  227  * The sync_mtx protects:
  228  *      bo->bo_synclist
  229  *      sync_vnode_count
  230  *      syncer_delayno
  231  *      syncer_state
  232  *      syncer_workitem_pending
  233  *      syncer_worklist_len
  234  *      rushjob
  235  */
  236 static struct mtx sync_mtx;
  237 static struct cv sync_wakeup;
  238 
  239 #define SYNCER_MAXDELAY         32
  240 static int syncer_maxdelay = SYNCER_MAXDELAY;   /* maximum delay time */
  241 static int syncdelay = 30;              /* max time to delay syncing data */
  242 static int filedelay = 30;              /* time to delay syncing files */
  243 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0,
  244     "Time to delay syncing files (in seconds)");
  245 static int dirdelay = 29;               /* time to delay syncing directories */
  246 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0,
  247     "Time to delay syncing directories (in seconds)");
  248 static int metadelay = 28;              /* time to delay syncing metadata */
  249 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0,
  250     "Time to delay syncing metadata (in seconds)");
  251 static int rushjob;             /* number of slots to run ASAP */
  252 static int stat_rush_requests;  /* number of times I/O speeded up */
  253 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0,
  254     "Number of times I/O speeded up (rush requests)");
  255 
  256 /*
  257  * When shutting down the syncer, run it at four times normal speed.
  258  */
  259 #define SYNCER_SHUTDOWN_SPEEDUP         4
  260 static int sync_vnode_count;
  261 static int syncer_worklist_len;
  262 static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
  263     syncer_state;
  264 
  265 /*
  266  * Number of vnodes we want to exist at any one time.  This is mostly used
  267  * to size hash tables in vnode-related code.  It is normally not used in
  268  * getnewvnode(), as wantfreevnodes is normally nonzero.)
  269  *
  270  * XXX desiredvnodes is historical cruft and should not exist.
  271  */
  272 int desiredvnodes;
  273 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
  274     &desiredvnodes, 0, "Maximum number of vnodes");
  275 SYSCTL_ULONG(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
  276     &wantfreevnodes, 0, "Minimum number of vnodes (legacy)");
  277 static int vnlru_nowhere;
  278 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
  279     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
  280 
  281 /*
  282  * Macros to control when a vnode is freed and recycled.  All require
  283  * the vnode interlock.
  284  */
  285 #define VCANRECYCLE(vp) (((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  286 #define VSHOULDFREE(vp) (!((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  287 #define VSHOULDBUSY(vp) (((vp)->v_iflag & VI_FREE) && (vp)->v_holdcnt)
  288 
  289 
  290 /*
  291  * Initialize the vnode management data structures.
  292  *
  293  * Reevaluate the following cap on the number of vnodes after the physical
  294  * memory size exceeds 512GB.  In the limit, as the physical memory size
  295  * grows, the ratio of physical pages to vnodes approaches sixteen to one.
  296  */
  297 #ifndef MAXVNODES_MAX
  298 #define MAXVNODES_MAX   (512 * (1024 * 1024 * 1024 / (int)PAGE_SIZE / 16))
  299 #endif
  300 static void
  301 vntblinit(void *dummy __unused)
  302 {
  303         int physvnodes, virtvnodes;
  304 
  305         /*
  306          * Desiredvnodes is a function of the physical memory size and the
  307          * kernel's heap size.  Generally speaking, it scales with the
  308          * physical memory size.  The ratio of desiredvnodes to physical pages
  309          * is one to four until desiredvnodes exceeds 98,304.  Thereafter, the
  310          * marginal ratio of desiredvnodes to physical pages is one to
  311          * sixteen.  However, desiredvnodes is limited by the kernel's heap
  312          * size.  The memory required by desiredvnodes vnodes and vm objects
  313          * may not exceed one seventh of the kernel's heap size.
  314          */
  315         physvnodes = maxproc + cnt.v_page_count / 16 + 3 * min(98304 * 4,
  316             cnt.v_page_count) / 16;
  317         virtvnodes = vm_kmem_size / (7 * (sizeof(struct vm_object) +
  318             sizeof(struct vnode)));
  319         desiredvnodes = min(physvnodes, virtvnodes);
  320         if (desiredvnodes > MAXVNODES_MAX) {
  321                 if (bootverbose)
  322                         printf("Reducing kern.maxvnodes %d -> %d\n",
  323                             desiredvnodes, MAXVNODES_MAX);
  324                 desiredvnodes = MAXVNODES_MAX;
  325         }
  326         wantfreevnodes = desiredvnodes / 4;
  327         mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
  328         TAILQ_INIT(&vnode_free_list);
  329         mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
  330         vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
  331             NULL, NULL, UMA_ALIGN_PTR, 0);
  332         vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
  333             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  334         /*
  335          * Initialize the filesystem syncer.
  336          */
  337         syncer_workitem_pending[WI_MPSAFEQ] = hashinit(syncer_maxdelay, M_VNODE,
  338             &syncer_mask);
  339         syncer_workitem_pending[WI_GIANTQ] = hashinit(syncer_maxdelay, M_VNODE,
  340             &syncer_mask);
  341         syncer_maxdelay = syncer_mask + 1;
  342         mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
  343         cv_init(&sync_wakeup, "syncer");
  344 }
  345 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL);
  346 
  347 
  348 /*
  349  * Mark a mount point as busy. Used to synchronize access and to delay
  350  * unmounting. Eventually, mountlist_mtx is not released on failure.
  351  *
  352  * vfs_busy() is a custom lock, it can block the caller.
  353  * vfs_busy() only sleeps if the unmount is active on the mount point.
  354  * For a mountpoint mp, vfs_busy-enforced lock is before lock of any
  355  * vnode belonging to mp.
  356  *
  357  * Lookup uses vfs_busy() to traverse mount points.
  358  * root fs                      var fs
  359  * / vnode lock         A       / vnode lock (/var)             D
  360  * /var vnode lock      B       /log vnode lock(/var/log)       E
  361  * vfs_busy lock        C       vfs_busy lock                   F
  362  *
  363  * Within each file system, the lock order is C->A->B and F->D->E.
  364  *
  365  * When traversing across mounts, the system follows that lock order:
  366  *
  367  *        C->A->B
  368  *              |
  369  *              +->F->D->E
  370  *
  371  * The lookup() process for namei("/var") illustrates the process:
  372  *  VOP_LOOKUP() obtains B while A is held
  373  *  vfs_busy() obtains a shared lock on F while A and B are held
  374  *  vput() releases lock on B
  375  *  vput() releases lock on A
  376  *  VFS_ROOT() obtains lock on D while shared lock on F is held
  377  *  vfs_unbusy() releases shared lock on F
  378  *  vn_lock() obtains lock on deadfs vnode vp_crossmp instead of A.
  379  *    Attempt to lock A (instead of vp_crossmp) while D is held would
  380  *    violate the global order, causing deadlocks.
  381  *
  382  * dounmount() locks B while F is drained.
  383  */
  384 int
  385 vfs_busy(struct mount *mp, int flags)
  386 {
  387 
  388         MPASS((flags & ~MBF_MASK) == 0);
  389         CTR3(KTR_VFS, "%s: mp %p with flags %d", __func__, mp, flags);
  390 
  391         MNT_ILOCK(mp);
  392         MNT_REF(mp);
  393         /*
  394          * If mount point is currenly being unmounted, sleep until the
  395          * mount point fate is decided.  If thread doing the unmounting fails,
  396          * it will clear MNTK_UNMOUNT flag before waking us up, indicating
  397          * that this mount point has survived the unmount attempt and vfs_busy
  398          * should retry.  Otherwise the unmounter thread will set MNTK_REFEXPIRE
  399          * flag in addition to MNTK_UNMOUNT, indicating that mount point is
  400          * about to be really destroyed.  vfs_busy needs to release its
  401          * reference on the mount point in this case and return with ENOENT,
  402          * telling the caller that mount mount it tried to busy is no longer
  403          * valid.
  404          */
  405         while (mp->mnt_kern_flag & MNTK_UNMOUNT) {
  406                 if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) {
  407                         MNT_REL(mp);
  408                         MNT_IUNLOCK(mp);
  409                         CTR1(KTR_VFS, "%s: failed busying before sleeping",
  410                             __func__);
  411                         return (ENOENT);
  412                 }
  413                 if (flags & MBF_MNTLSTLOCK)
  414                         mtx_unlock(&mountlist_mtx);
  415                 mp->mnt_kern_flag |= MNTK_MWAIT;
  416                 msleep(mp, MNT_MTX(mp), PVFS | PDROP, "vfs_busy", 0);
  417                 if (flags & MBF_MNTLSTLOCK)
  418                         mtx_lock(&mountlist_mtx);
  419                 MNT_ILOCK(mp);
  420         }
  421         if (flags & MBF_MNTLSTLOCK)
  422                 mtx_unlock(&mountlist_mtx);
  423         mp->mnt_lockref++;
  424         MNT_IUNLOCK(mp);
  425         return (0);
  426 }
  427 
  428 /*
  429  * Free a busy filesystem.
  430  */
  431 void
  432 vfs_unbusy(struct mount *mp)
  433 {
  434 
  435         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  436         MNT_ILOCK(mp);
  437         MNT_REL(mp);
  438         KASSERT(mp->mnt_lockref > 0, ("negative mnt_lockref"));
  439         mp->mnt_lockref--;
  440         if (mp->mnt_lockref == 0 && (mp->mnt_kern_flag & MNTK_DRAINING) != 0) {
  441                 MPASS(mp->mnt_kern_flag & MNTK_UNMOUNT);
  442                 CTR1(KTR_VFS, "%s: waking up waiters", __func__);
  443                 mp->mnt_kern_flag &= ~MNTK_DRAINING;
  444                 wakeup(&mp->mnt_lockref);
  445         }
  446         MNT_IUNLOCK(mp);
  447 }
  448 
  449 /*
  450  * Lookup a mount point by filesystem identifier.
  451  */
  452 struct mount *
  453 vfs_getvfs(fsid_t *fsid)
  454 {
  455         struct mount *mp;
  456 
  457         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  458         mtx_lock(&mountlist_mtx);
  459         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  460                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  461                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  462                         vfs_ref(mp);
  463                         mtx_unlock(&mountlist_mtx);
  464                         return (mp);
  465                 }
  466         }
  467         mtx_unlock(&mountlist_mtx);
  468         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  469         return ((struct mount *) 0);
  470 }
  471 
  472 /*
  473  * Lookup a mount point by filesystem identifier, busying it before
  474  * returning.
  475  */
  476 struct mount *
  477 vfs_busyfs(fsid_t *fsid)
  478 {
  479         struct mount *mp;
  480         int error;
  481 
  482         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  483         mtx_lock(&mountlist_mtx);
  484         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  485                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  486                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  487                         error = vfs_busy(mp, MBF_MNTLSTLOCK);
  488                         if (error) {
  489                                 mtx_unlock(&mountlist_mtx);
  490                                 return (NULL);
  491                         }
  492                         return (mp);
  493                 }
  494         }
  495         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  496         mtx_unlock(&mountlist_mtx);
  497         return ((struct mount *) 0);
  498 }
  499 
  500 /*
  501  * Check if a user can access privileged mount options.
  502  */
  503 int
  504 vfs_suser(struct mount *mp, struct thread *td)
  505 {
  506         int error;
  507 
  508         /*
  509          * If the thread is jailed, but this is not a jail-friendly file
  510          * system, deny immediately.
  511          */
  512         if (!(mp->mnt_vfc->vfc_flags & VFCF_JAIL) && jailed(td->td_ucred))
  513                 return (EPERM);
  514 
  515         /*
  516          * If the file system was mounted outside the jail of the calling
  517          * thread, deny immediately.
  518          */
  519         if (prison_check(td->td_ucred, mp->mnt_cred) != 0)
  520                 return (EPERM);
  521 
  522         /*
  523          * If file system supports delegated administration, we don't check
  524          * for the PRIV_VFS_MOUNT_OWNER privilege - it will be better verified
  525          * by the file system itself.
  526          * If this is not the user that did original mount, we check for
  527          * the PRIV_VFS_MOUNT_OWNER privilege.
  528          */
  529         if (!(mp->mnt_vfc->vfc_flags & VFCF_DELEGADMIN) &&
  530             mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
  531                 if ((error = priv_check(td, PRIV_VFS_MOUNT_OWNER)) != 0)
  532                         return (error);
  533         }
  534         return (0);
  535 }
  536 
  537 /*
  538  * Get a new unique fsid.  Try to make its val[0] unique, since this value
  539  * will be used to create fake device numbers for stat().  Also try (but
  540  * not so hard) make its val[0] unique mod 2^16, since some emulators only
  541  * support 16-bit device numbers.  We end up with unique val[0]'s for the
  542  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
  543  *
  544  * Keep in mind that several mounts may be running in parallel.  Starting
  545  * the search one past where the previous search terminated is both a
  546  * micro-optimization and a defense against returning the same fsid to
  547  * different mounts.
  548  */
  549 void
  550 vfs_getnewfsid(struct mount *mp)
  551 {
  552         static uint16_t mntid_base;
  553         struct mount *nmp;
  554         fsid_t tfsid;
  555         int mtype;
  556 
  557         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  558         mtx_lock(&mntid_mtx);
  559         mtype = mp->mnt_vfc->vfc_typenum;
  560         tfsid.val[1] = mtype;
  561         mtype = (mtype & 0xFF) << 24;
  562         for (;;) {
  563                 tfsid.val[0] = makedev(255,
  564                     mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
  565                 mntid_base++;
  566                 if ((nmp = vfs_getvfs(&tfsid)) == NULL)
  567                         break;
  568                 vfs_rel(nmp);
  569         }
  570         mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
  571         mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
  572         mtx_unlock(&mntid_mtx);
  573 }
  574 
  575 /*
  576  * Knob to control the precision of file timestamps:
  577  *
  578  *   0 = seconds only; nanoseconds zeroed.
  579  *   1 = seconds and nanoseconds, accurate within 1/HZ.
  580  *   2 = seconds and nanoseconds, truncated to microseconds.
  581  * >=3 = seconds and nanoseconds, maximum precision.
  582  */
  583 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
  584 
  585 static int timestamp_precision = TSP_SEC;
  586 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
  587     &timestamp_precision, 0, "File timestamp precision (0: seconds, "
  588     "1: sec + ns accurate to 1/HZ, 2: sec + ns truncated to ms, "
  589     "3+: sec + ns (max. precision))");
  590 
  591 /*
  592  * Get a current timestamp.
  593  */
  594 void
  595 vfs_timestamp(struct timespec *tsp)
  596 {
  597         struct timeval tv;
  598 
  599         switch (timestamp_precision) {
  600         case TSP_SEC:
  601                 tsp->tv_sec = time_second;
  602                 tsp->tv_nsec = 0;
  603                 break;
  604         case TSP_HZ:
  605                 getnanotime(tsp);
  606                 break;
  607         case TSP_USEC:
  608                 microtime(&tv);
  609                 TIMEVAL_TO_TIMESPEC(&tv, tsp);
  610                 break;
  611         case TSP_NSEC:
  612         default:
  613                 nanotime(tsp);
  614                 break;
  615         }
  616 }
  617 
  618 /*
  619  * Set vnode attributes to VNOVAL
  620  */
  621 void
  622 vattr_null(struct vattr *vap)
  623 {
  624 
  625         vap->va_type = VNON;
  626         vap->va_size = VNOVAL;
  627         vap->va_bytes = VNOVAL;
  628         vap->va_mode = VNOVAL;
  629         vap->va_nlink = VNOVAL;
  630         vap->va_uid = VNOVAL;
  631         vap->va_gid = VNOVAL;
  632         vap->va_fsid = VNOVAL;
  633         vap->va_fileid = VNOVAL;
  634         vap->va_blocksize = VNOVAL;
  635         vap->va_rdev = VNOVAL;
  636         vap->va_atime.tv_sec = VNOVAL;
  637         vap->va_atime.tv_nsec = VNOVAL;
  638         vap->va_mtime.tv_sec = VNOVAL;
  639         vap->va_mtime.tv_nsec = VNOVAL;
  640         vap->va_ctime.tv_sec = VNOVAL;
  641         vap->va_ctime.tv_nsec = VNOVAL;
  642         vap->va_birthtime.tv_sec = VNOVAL;
  643         vap->va_birthtime.tv_nsec = VNOVAL;
  644         vap->va_flags = VNOVAL;
  645         vap->va_gen = VNOVAL;
  646         vap->va_vaflags = 0;
  647 }
  648 
  649 /*
  650  * This routine is called when we have too many vnodes.  It attempts
  651  * to free <count> vnodes and will potentially free vnodes that still
  652  * have VM backing store (VM backing store is typically the cause
  653  * of a vnode blowout so we want to do this).  Therefore, this operation
  654  * is not considered cheap.
  655  *
  656  * A number of conditions may prevent a vnode from being reclaimed.
  657  * the buffer cache may have references on the vnode, a directory
  658  * vnode may still have references due to the namei cache representing
  659  * underlying files, or the vnode may be in active use.   It is not
  660  * desireable to reuse such vnodes.  These conditions may cause the
  661  * number of vnodes to reach some minimum value regardless of what
  662  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
  663  */
  664 static int
  665 vlrureclaim(struct mount *mp)
  666 {
  667         struct vnode *vp;
  668         int done;
  669         int trigger;
  670         int usevnodes;
  671         int count;
  672 
  673         /*
  674          * Calculate the trigger point, don't allow user
  675          * screwups to blow us up.   This prevents us from
  676          * recycling vnodes with lots of resident pages.  We
  677          * aren't trying to free memory, we are trying to
  678          * free vnodes.
  679          */
  680         usevnodes = desiredvnodes;
  681         if (usevnodes <= 0)
  682                 usevnodes = 1;
  683         trigger = cnt.v_page_count * 2 / usevnodes;
  684         done = 0;
  685         vn_start_write(NULL, &mp, V_WAIT);
  686         MNT_ILOCK(mp);
  687         count = mp->mnt_nvnodelistsize / 10 + 1;
  688         while (count != 0) {
  689                 vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
  690                 while (vp != NULL && vp->v_type == VMARKER)
  691                         vp = TAILQ_NEXT(vp, v_nmntvnodes);
  692                 if (vp == NULL)
  693                         break;
  694                 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  695                 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  696                 --count;
  697                 if (!VI_TRYLOCK(vp))
  698                         goto next_iter;
  699                 /*
  700                  * If it's been deconstructed already, it's still
  701                  * referenced, or it exceeds the trigger, skip it.
  702                  */
  703                 if (vp->v_usecount ||
  704                     (!vlru_allow_cache_src &&
  705                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  706                     (vp->v_iflag & VI_DOOMED) != 0 || (vp->v_object != NULL &&
  707                     vp->v_object->resident_page_count > trigger)) {
  708                         VI_UNLOCK(vp);
  709                         goto next_iter;
  710                 }
  711                 MNT_IUNLOCK(mp);
  712                 vholdl(vp);
  713                 if (VOP_LOCK(vp, LK_INTERLOCK|LK_EXCLUSIVE|LK_NOWAIT)) {
  714                         vdrop(vp);
  715                         goto next_iter_mntunlocked;
  716                 }
  717                 VI_LOCK(vp);
  718                 /*
  719                  * v_usecount may have been bumped after VOP_LOCK() dropped
  720                  * the vnode interlock and before it was locked again.
  721                  *
  722                  * It is not necessary to recheck VI_DOOMED because it can
  723                  * only be set by another thread that holds both the vnode
  724                  * lock and vnode interlock.  If another thread has the
  725                  * vnode lock before we get to VOP_LOCK() and obtains the
  726                  * vnode interlock after VOP_LOCK() drops the vnode
  727                  * interlock, the other thread will be unable to drop the
  728                  * vnode lock before our VOP_LOCK() call fails.
  729                  */
  730                 if (vp->v_usecount ||
  731                     (!vlru_allow_cache_src &&
  732                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  733                     (vp->v_object != NULL &&
  734                     vp->v_object->resident_page_count > trigger)) {
  735                         VOP_UNLOCK(vp, LK_INTERLOCK);
  736                         goto next_iter_mntunlocked;
  737                 }
  738                 KASSERT((vp->v_iflag & VI_DOOMED) == 0,
  739                     ("VI_DOOMED unexpectedly detected in vlrureclaim()"));
  740                 vgonel(vp);
  741                 VOP_UNLOCK(vp, 0);
  742                 vdropl(vp);
  743                 done++;
  744 next_iter_mntunlocked:
  745                 if (!should_yield())
  746                         goto relock_mnt;
  747                 goto yield;
  748 next_iter:
  749                 if (!should_yield())
  750                         continue;
  751                 MNT_IUNLOCK(mp);
  752 yield:
  753                 kern_yield(PRI_UNCHANGED);
  754 relock_mnt:
  755                 MNT_ILOCK(mp);
  756         }
  757         MNT_IUNLOCK(mp);
  758         vn_finished_write(mp);
  759         return done;
  760 }
  761 
  762 /*
  763  * Attempt to keep the free list at wantfreevnodes length.
  764  */
  765 static void
  766 vnlru_free(int count)
  767 {
  768         struct vnode *vp;
  769         int vfslocked;
  770 
  771         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
  772         for (; count > 0; count--) {
  773                 vp = TAILQ_FIRST(&vnode_free_list);
  774                 /*
  775                  * The list can be modified while the free_list_mtx
  776                  * has been dropped and vp could be NULL here.
  777                  */
  778                 if (!vp)
  779                         break;
  780                 VNASSERT(vp->v_op != NULL, vp,
  781                     ("vnlru_free: vnode already reclaimed."));
  782                 TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
  783                 /*
  784                  * Don't recycle if we can't get the interlock.
  785                  */
  786                 if (!VI_TRYLOCK(vp)) {
  787                         TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
  788                         continue;
  789                 }
  790                 VNASSERT(VCANRECYCLE(vp), vp,
  791                     ("vp inconsistent on freelist"));
  792                 freevnodes--;
  793                 vp->v_iflag &= ~VI_FREE;
  794                 vholdl(vp);
  795                 mtx_unlock(&vnode_free_list_mtx);
  796                 VI_UNLOCK(vp);
  797                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  798                 vtryrecycle(vp);
  799                 VFS_UNLOCK_GIANT(vfslocked);
  800                 /*
  801                  * If the recycled succeeded this vdrop will actually free
  802                  * the vnode.  If not it will simply place it back on
  803                  * the free list.
  804                  */
  805                 vdrop(vp);
  806                 mtx_lock(&vnode_free_list_mtx);
  807         }
  808 }
  809 /*
  810  * Attempt to recycle vnodes in a context that is always safe to block.
  811  * Calling vlrurecycle() from the bowels of filesystem code has some
  812  * interesting deadlock problems.
  813  */
  814 static struct proc *vnlruproc;
  815 static int vnlruproc_sig;
  816 
  817 static void
  818 vnlru_proc(void)
  819 {
  820         struct mount *mp, *nmp;
  821         int done, vfslocked;
  822         struct proc *p = vnlruproc;
  823 
  824         EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
  825             SHUTDOWN_PRI_FIRST);
  826 
  827         for (;;) {
  828                 kproc_suspend_check(p);
  829                 mtx_lock(&vnode_free_list_mtx);
  830                 if (freevnodes > wantfreevnodes)
  831                         vnlru_free(freevnodes - wantfreevnodes);
  832                 if (numvnodes <= desiredvnodes * 9 / 10) {
  833                         vnlruproc_sig = 0;
  834                         wakeup(&vnlruproc_sig);
  835                         msleep(vnlruproc, &vnode_free_list_mtx,
  836                             PVFS|PDROP, "vlruwt", hz);
  837                         continue;
  838                 }
  839                 mtx_unlock(&vnode_free_list_mtx);
  840                 done = 0;
  841                 mtx_lock(&mountlist_mtx);
  842                 for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
  843                         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
  844                                 nmp = TAILQ_NEXT(mp, mnt_list);
  845                                 continue;
  846                         }
  847                         vfslocked = VFS_LOCK_GIANT(mp);
  848                         done += vlrureclaim(mp);
  849                         VFS_UNLOCK_GIANT(vfslocked);
  850                         mtx_lock(&mountlist_mtx);
  851                         nmp = TAILQ_NEXT(mp, mnt_list);
  852                         vfs_unbusy(mp);
  853                 }
  854                 mtx_unlock(&mountlist_mtx);
  855                 if (done == 0) {
  856 #if 0
  857                         /* These messages are temporary debugging aids */
  858                         if (vnlru_nowhere < 5)
  859                                 printf("vnlru process getting nowhere..\n");
  860                         else if (vnlru_nowhere == 5)
  861                                 printf("vnlru process messages stopped.\n");
  862 #endif
  863                         vnlru_nowhere++;
  864                         tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
  865                 } else
  866                         kern_yield(PRI_UNCHANGED);
  867         }
  868 }
  869 
  870 static struct kproc_desc vnlru_kp = {
  871         "vnlru",
  872         vnlru_proc,
  873         &vnlruproc
  874 };
  875 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start,
  876     &vnlru_kp);
  877  
  878 /*
  879  * Routines having to do with the management of the vnode table.
  880  */
  881 
  882 void
  883 vdestroy(struct vnode *vp)
  884 {
  885         struct bufobj *bo;
  886 
  887         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  888         mtx_lock(&vnode_free_list_mtx);
  889         numvnodes--;
  890         mtx_unlock(&vnode_free_list_mtx);
  891         bo = &vp->v_bufobj;
  892         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
  893             ("cleaned vnode still on the free list."));
  894         VNASSERT(vp->v_data == NULL, vp, ("cleaned vnode isn't"));
  895         VNASSERT(vp->v_holdcnt == 0, vp, ("Non-zero hold count"));
  896         VNASSERT(vp->v_usecount == 0, vp, ("Non-zero use count"));
  897         VNASSERT(vp->v_writecount == 0, vp, ("Non-zero write count"));
  898         VNASSERT(bo->bo_numoutput == 0, vp, ("Clean vnode has pending I/O's"));
  899         VNASSERT(bo->bo_clean.bv_cnt == 0, vp, ("cleanbufcnt not 0"));
  900         VNASSERT(bo->bo_clean.bv_root == NULL, vp, ("cleanblkroot not NULL"));
  901         VNASSERT(bo->bo_dirty.bv_cnt == 0, vp, ("dirtybufcnt not 0"));
  902         VNASSERT(bo->bo_dirty.bv_root == NULL, vp, ("dirtyblkroot not NULL"));
  903         VNASSERT(TAILQ_EMPTY(&vp->v_cache_dst), vp, ("vp has namecache dst"));
  904         VNASSERT(LIST_EMPTY(&vp->v_cache_src), vp, ("vp has namecache src"));
  905         VNASSERT(vp->v_cache_dd == NULL, vp, ("vp has namecache for .."));
  906         VI_UNLOCK(vp);
  907 #ifdef MAC
  908         mac_vnode_destroy(vp);
  909 #endif
  910         if (vp->v_pollinfo != NULL)
  911                 destroy_vpollinfo(vp->v_pollinfo);
  912 #ifdef INVARIANTS
  913         /* XXX Elsewhere we can detect an already freed vnode via NULL v_op. */
  914         vp->v_op = NULL;
  915 #endif
  916         lockdestroy(vp->v_vnlock);
  917         mtx_destroy(&vp->v_interlock);
  918         mtx_destroy(BO_MTX(bo));
  919         uma_zfree(vnode_zone, vp);
  920 }
  921 
  922 /*
  923  * Try to recycle a freed vnode.  We abort if anyone picks up a reference
  924  * before we actually vgone().  This function must be called with the vnode
  925  * held to prevent the vnode from being returned to the free list midway
  926  * through vgone().
  927  */
  928 static int
  929 vtryrecycle(struct vnode *vp)
  930 {
  931         struct mount *vnmp;
  932 
  933         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  934         VNASSERT(vp->v_holdcnt, vp,
  935             ("vtryrecycle: Recycling vp %p without a reference.", vp));
  936         /*
  937          * This vnode may found and locked via some other list, if so we
  938          * can't recycle it yet.
  939          */
  940         if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
  941                 CTR2(KTR_VFS,
  942                     "%s: impossible to recycle, vp %p lock is already held",
  943                     __func__, vp);
  944                 return (EWOULDBLOCK);
  945         }
  946         /*
  947          * Don't recycle if its filesystem is being suspended.
  948          */
  949         if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
  950                 VOP_UNLOCK(vp, 0);
  951                 CTR2(KTR_VFS,
  952                     "%s: impossible to recycle, cannot start the write for %p",
  953                     __func__, vp);
  954                 return (EBUSY);
  955         }
  956         /*
  957          * If we got this far, we need to acquire the interlock and see if
  958          * anyone picked up this vnode from another list.  If not, we will
  959          * mark it with DOOMED via vgonel() so that anyone who does find it
  960          * will skip over it.
  961          */
  962         VI_LOCK(vp);
  963         if (vp->v_usecount) {
  964                 VOP_UNLOCK(vp, LK_INTERLOCK);
  965                 vn_finished_write(vnmp);
  966                 CTR2(KTR_VFS,
  967                     "%s: impossible to recycle, %p is already referenced",
  968                     __func__, vp);
  969                 return (EBUSY);
  970         }
  971         if ((vp->v_iflag & VI_DOOMED) == 0)
  972                 vgonel(vp);
  973         VOP_UNLOCK(vp, LK_INTERLOCK);
  974         vn_finished_write(vnmp);
  975         return (0);
  976 }
  977 
  978 /*
  979  * Return the next vnode from the free list.
  980  */
  981 int
  982 getnewvnode(const char *tag, struct mount *mp, struct vop_vector *vops,
  983     struct vnode **vpp)
  984 {
  985         struct vnode *vp = NULL;
  986         struct bufobj *bo;
  987 
  988         CTR3(KTR_VFS, "%s: mp %p with tag %s", __func__, mp, tag);
  989         mtx_lock(&vnode_free_list_mtx);
  990         /*
  991          * Lend our context to reclaim vnodes if they've exceeded the max.
  992          */
  993         if (freevnodes > wantfreevnodes)
  994                 vnlru_free(1);
  995         /*
  996          * Wait for available vnodes.
  997          */
  998         if (numvnodes > desiredvnodes) {
  999                 if (mp != NULL && (mp->mnt_kern_flag & MNTK_SUSPEND)) {
 1000                         /*
 1001                          * File system is beeing suspended, we cannot risk a
 1002                          * deadlock here, so allocate new vnode anyway.
 1003                          */
 1004                         if (freevnodes > wantfreevnodes)
 1005                                 vnlru_free(freevnodes - wantfreevnodes);
 1006                         goto alloc;
 1007                 }
 1008                 if (vnlruproc_sig == 0) {
 1009                         vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
 1010                         wakeup(vnlruproc);
 1011                 }
 1012                 msleep(&vnlruproc_sig, &vnode_free_list_mtx, PVFS,
 1013                     "vlruwk", hz);
 1014 #if 0   /* XXX Not all VFS_VGET/ffs_vget callers check returns. */
 1015                 if (numvnodes > desiredvnodes) {
 1016                         mtx_unlock(&vnode_free_list_mtx);
 1017                         return (ENFILE);
 1018                 }
 1019 #endif
 1020         }
 1021 alloc:
 1022         numvnodes++;
 1023         mtx_unlock(&vnode_free_list_mtx);
 1024         vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
 1025         /*
 1026          * Setup locks.
 1027          */
 1028         vp->v_vnlock = &vp->v_lock;
 1029         mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
 1030         /*
 1031          * By default, don't allow shared locks unless filesystems
 1032          * opt-in.
 1033          */
 1034         lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOSHARE);
 1035         /*
 1036          * Initialize bufobj.
 1037          */
 1038         bo = &vp->v_bufobj;
 1039         bo->__bo_vnode = vp;
 1040         mtx_init(BO_MTX(bo), "bufobj interlock", NULL, MTX_DEF);
 1041         bo->bo_ops = &buf_ops_bio;
 1042         bo->bo_private = vp;
 1043         TAILQ_INIT(&bo->bo_clean.bv_hd);
 1044         TAILQ_INIT(&bo->bo_dirty.bv_hd);
 1045         /*
 1046          * Initialize namecache.
 1047          */
 1048         LIST_INIT(&vp->v_cache_src);
 1049         TAILQ_INIT(&vp->v_cache_dst);
 1050         /*
 1051          * Finalize various vnode identity bits.
 1052          */
 1053         vp->v_type = VNON;
 1054         vp->v_tag = tag;
 1055         vp->v_op = vops;
 1056         v_incr_usecount(vp);
 1057         vp->v_data = 0;
 1058 #ifdef MAC
 1059         mac_vnode_init(vp);
 1060         if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
 1061                 mac_vnode_associate_singlelabel(mp, vp);
 1062         else if (mp == NULL && vops != &dead_vnodeops)
 1063                 printf("NULL mp in getnewvnode()\n");
 1064 #endif
 1065         if (mp != NULL) {
 1066                 bo->bo_bsize = mp->mnt_stat.f_iosize;
 1067                 if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
 1068                         vp->v_vflag |= VV_NOKNOTE;
 1069         }
 1070 
 1071         *vpp = vp;
 1072         return (0);
 1073 }
 1074 
 1075 /*
 1076  * Delete from old mount point vnode list, if on one.
 1077  */
 1078 static void
 1079 delmntque(struct vnode *vp)
 1080 {
 1081         struct mount *mp;
 1082 
 1083         mp = vp->v_mount;
 1084         if (mp == NULL)
 1085                 return;
 1086         MNT_ILOCK(mp);
 1087         vp->v_mount = NULL;
 1088         VNASSERT(mp->mnt_nvnodelistsize > 0, vp,
 1089                 ("bad mount point vnode list size"));
 1090         TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1091         mp->mnt_nvnodelistsize--;
 1092         MNT_REL(mp);
 1093         MNT_IUNLOCK(mp);
 1094 }
 1095 
 1096 static void
 1097 insmntque_stddtr(struct vnode *vp, void *dtr_arg)
 1098 {
 1099 
 1100         vp->v_data = NULL;
 1101         vp->v_op = &dead_vnodeops;
 1102         /* XXX non mp-safe fs may still call insmntque with vnode
 1103            unlocked */
 1104         if (!VOP_ISLOCKED(vp))
 1105                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1106         vgone(vp);
 1107         vput(vp);
 1108 }
 1109 
 1110 /*
 1111  * Insert into list of vnodes for the new mount point, if available.
 1112  */
 1113 int
 1114 insmntque1(struct vnode *vp, struct mount *mp,
 1115         void (*dtr)(struct vnode *, void *), void *dtr_arg)
 1116 {
 1117         int locked;
 1118 
 1119         KASSERT(vp->v_mount == NULL,
 1120                 ("insmntque: vnode already on per mount vnode list"));
 1121         VNASSERT(mp != NULL, vp, ("Don't call insmntque(foo, NULL)"));
 1122 #ifdef DEBUG_VFS_LOCKS
 1123         if (!VFS_NEEDSGIANT(mp))
 1124                 ASSERT_VOP_ELOCKED(vp,
 1125                     "insmntque: mp-safe fs and non-locked vp");
 1126 #endif
 1127         MNT_ILOCK(mp);
 1128         if ((mp->mnt_kern_flag & MNTK_NOINSMNTQ) != 0 &&
 1129             ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0 ||
 1130              mp->mnt_nvnodelistsize == 0)) {
 1131                 locked = VOP_ISLOCKED(vp);
 1132                 if (!locked || (locked == LK_EXCLUSIVE &&
 1133                      (vp->v_vflag & VV_FORCEINSMQ) == 0)) {
 1134                         MNT_IUNLOCK(mp);
 1135                         if (dtr != NULL)
 1136                                 dtr(vp, dtr_arg);
 1137                         return (EBUSY);
 1138                 }
 1139         }
 1140         vp->v_mount = mp;
 1141         MNT_REF(mp);
 1142         TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1143         VNASSERT(mp->mnt_nvnodelistsize >= 0, vp,
 1144                 ("neg mount point vnode list size"));
 1145         mp->mnt_nvnodelistsize++;
 1146         MNT_IUNLOCK(mp);
 1147         return (0);
 1148 }
 1149 
 1150 int
 1151 insmntque(struct vnode *vp, struct mount *mp)
 1152 {
 1153 
 1154         return (insmntque1(vp, mp, insmntque_stddtr, NULL));
 1155 }
 1156 
 1157 /*
 1158  * Flush out and invalidate all buffers associated with a bufobj
 1159  * Called with the underlying object locked.
 1160  */
 1161 int
 1162 bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo)
 1163 {
 1164         int error;
 1165 
 1166         BO_LOCK(bo);
 1167         if (flags & V_SAVE) {
 1168                 error = bufobj_wwait(bo, slpflag, slptimeo);
 1169                 if (error) {
 1170                         BO_UNLOCK(bo);
 1171                         return (error);
 1172                 }
 1173                 if (bo->bo_dirty.bv_cnt > 0) {
 1174                         BO_UNLOCK(bo);
 1175                         if ((error = BO_SYNC(bo, MNT_WAIT)) != 0)
 1176                                 return (error);
 1177                         /*
 1178                          * XXX We could save a lock/unlock if this was only
 1179                          * enabled under INVARIANTS
 1180                          */
 1181                         BO_LOCK(bo);
 1182                         if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
 1183                                 panic("vinvalbuf: dirty bufs");
 1184                 }
 1185         }
 1186         /*
 1187          * If you alter this loop please notice that interlock is dropped and
 1188          * reacquired in flushbuflist.  Special care is needed to ensure that
 1189          * no race conditions occur from this.
 1190          */
 1191         do {
 1192                 error = flushbuflist(&bo->bo_clean,
 1193                     flags, bo, slpflag, slptimeo);
 1194                 if (error == 0)
 1195                         error = flushbuflist(&bo->bo_dirty,
 1196                             flags, bo, slpflag, slptimeo);
 1197                 if (error != 0 && error != EAGAIN) {
 1198                         BO_UNLOCK(bo);
 1199                         return (error);
 1200                 }
 1201         } while (error != 0);
 1202 
 1203         /*
 1204          * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
 1205          * have write I/O in-progress but if there is a VM object then the
 1206          * VM object can also have read-I/O in-progress.
 1207          */
 1208         do {
 1209                 bufobj_wwait(bo, 0, 0);
 1210                 BO_UNLOCK(bo);
 1211                 if (bo->bo_object != NULL) {
 1212                         VM_OBJECT_LOCK(bo->bo_object);
 1213                         vm_object_pip_wait(bo->bo_object, "bovlbx");
 1214                         VM_OBJECT_UNLOCK(bo->bo_object);
 1215                 }
 1216                 BO_LOCK(bo);
 1217         } while (bo->bo_numoutput > 0);
 1218         BO_UNLOCK(bo);
 1219 
 1220         /*
 1221          * Destroy the copy in the VM cache, too.
 1222          */
 1223         if (bo->bo_object != NULL && (flags & (V_ALT | V_NORMAL)) == 0) {
 1224                 VM_OBJECT_LOCK(bo->bo_object);
 1225                 vm_object_page_remove(bo->bo_object, 0, 0, (flags & V_SAVE) ?
 1226                     OBJPR_CLEANONLY : 0);
 1227                 VM_OBJECT_UNLOCK(bo->bo_object);
 1228         }
 1229 
 1230 #ifdef INVARIANTS
 1231         BO_LOCK(bo);
 1232         if ((flags & (V_ALT | V_NORMAL)) == 0 &&
 1233             (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
 1234                 panic("vinvalbuf: flush failed");
 1235         BO_UNLOCK(bo);
 1236 #endif
 1237         return (0);
 1238 }
 1239 
 1240 /*
 1241  * Flush out and invalidate all buffers associated with a vnode.
 1242  * Called with the underlying object locked.
 1243  */
 1244 int
 1245 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
 1246 {
 1247 
 1248         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 1249         ASSERT_VOP_LOCKED(vp, "vinvalbuf");
 1250         return (bufobj_invalbuf(&vp->v_bufobj, flags, slpflag, slptimeo));
 1251 }
 1252 
 1253 /*
 1254  * Flush out buffers on the specified list.
 1255  *
 1256  */
 1257 static int
 1258 flushbuflist( struct bufv *bufv, int flags, struct bufobj *bo, int slpflag,
 1259     int slptimeo)
 1260 {
 1261         struct buf *bp, *nbp;
 1262         int retval, error;
 1263         daddr_t lblkno;
 1264         b_xflags_t xflags;
 1265 
 1266         ASSERT_BO_LOCKED(bo);
 1267 
 1268         retval = 0;
 1269         TAILQ_FOREACH_SAFE(bp, &bufv->bv_hd, b_bobufs, nbp) {
 1270                 if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
 1271                     ((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
 1272                         continue;
 1273                 }
 1274                 lblkno = 0;
 1275                 xflags = 0;
 1276                 if (nbp != NULL) {
 1277                         lblkno = nbp->b_lblkno;
 1278                         xflags = nbp->b_xflags &
 1279                                 (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN);
 1280                 }
 1281                 retval = EAGAIN;
 1282                 error = BUF_TIMELOCK(bp,
 1283                     LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, BO_MTX(bo),
 1284                     "flushbuf", slpflag, slptimeo);
 1285                 if (error) {
 1286                         BO_LOCK(bo);
 1287                         return (error != ENOLCK ? error : EAGAIN);
 1288                 }
 1289                 KASSERT(bp->b_bufobj == bo,
 1290                     ("bp %p wrong b_bufobj %p should be %p",
 1291                     bp, bp->b_bufobj, bo));
 1292                 if (bp->b_bufobj != bo) {       /* XXX: necessary ? */
 1293                         BUF_UNLOCK(bp);
 1294                         BO_LOCK(bo);
 1295                         return (EAGAIN);
 1296                 }
 1297                 /*
 1298                  * XXX Since there are no node locks for NFS, I
 1299                  * believe there is a slight chance that a delayed
 1300                  * write will occur while sleeping just above, so
 1301                  * check for it.
 1302                  */
 1303                 if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
 1304                     (flags & V_SAVE)) {
 1305                         BO_LOCK(bo);
 1306                         bremfree(bp);
 1307                         BO_UNLOCK(bo);
 1308                         bp->b_flags |= B_ASYNC;
 1309                         bwrite(bp);
 1310                         BO_LOCK(bo);
 1311                         return (EAGAIN);        /* XXX: why not loop ? */
 1312                 }
 1313                 BO_LOCK(bo);
 1314                 bremfree(bp);
 1315                 BO_UNLOCK(bo);
 1316                 bp->b_flags |= (B_INVAL | B_RELBUF);
 1317                 bp->b_flags &= ~B_ASYNC;
 1318                 brelse(bp);
 1319                 BO_LOCK(bo);
 1320                 if (nbp != NULL &&
 1321                     (nbp->b_bufobj != bo ||
 1322                      nbp->b_lblkno != lblkno ||
 1323                      (nbp->b_xflags &
 1324                       (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN)) != xflags))
 1325                         break;                  /* nbp invalid */
 1326         }
 1327         return (retval);
 1328 }
 1329 
 1330 /*
 1331  * Truncate a file's buffer and pages to a specified length.  This
 1332  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
 1333  * sync activity.
 1334  */
 1335 int
 1336 vtruncbuf(struct vnode *vp, struct ucred *cred, struct thread *td,
 1337     off_t length, int blksize)
 1338 {
 1339         struct buf *bp, *nbp;
 1340         int anyfreed;
 1341         int trunclbn;
 1342         struct bufobj *bo;
 1343 
 1344         CTR5(KTR_VFS, "%s: vp %p with cred %p and block %d:%ju", __func__,
 1345             vp, cred, blksize, (uintmax_t)length);
 1346 
 1347         /*
 1348          * Round up to the *next* lbn.
 1349          */
 1350         trunclbn = (length + blksize - 1) / blksize;
 1351 
 1352         ASSERT_VOP_LOCKED(vp, "vtruncbuf");
 1353 restart:
 1354         bo = &vp->v_bufobj;
 1355         BO_LOCK(bo);
 1356         anyfreed = 1;
 1357         for (;anyfreed;) {
 1358                 anyfreed = 0;
 1359                 TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
 1360                         if (bp->b_lblkno < trunclbn)
 1361                                 continue;
 1362                         if (BUF_LOCK(bp,
 1363                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1364                             BO_MTX(bo)) == ENOLCK)
 1365                                 goto restart;
 1366 
 1367                         BO_LOCK(bo);
 1368                         bremfree(bp);
 1369                         BO_UNLOCK(bo);
 1370                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1371                         bp->b_flags &= ~B_ASYNC;
 1372                         brelse(bp);
 1373                         anyfreed = 1;
 1374 
 1375                         BO_LOCK(bo);
 1376                         if (nbp != NULL &&
 1377                             (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
 1378                             (nbp->b_vp != vp) ||
 1379                             (nbp->b_flags & B_DELWRI))) {
 1380                                 BO_UNLOCK(bo);
 1381                                 goto restart;
 1382                         }
 1383                 }
 1384 
 1385                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1386                         if (bp->b_lblkno < trunclbn)
 1387                                 continue;
 1388                         if (BUF_LOCK(bp,
 1389                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1390                             BO_MTX(bo)) == ENOLCK)
 1391                                 goto restart;
 1392                         BO_LOCK(bo);
 1393                         bremfree(bp);
 1394                         BO_UNLOCK(bo);
 1395                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1396                         bp->b_flags &= ~B_ASYNC;
 1397                         brelse(bp);
 1398                         anyfreed = 1;
 1399 
 1400                         BO_LOCK(bo);
 1401                         if (nbp != NULL &&
 1402                             (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
 1403                             (nbp->b_vp != vp) ||
 1404                             (nbp->b_flags & B_DELWRI) == 0)) {
 1405                                 BO_UNLOCK(bo);
 1406                                 goto restart;
 1407                         }
 1408                 }
 1409         }
 1410 
 1411         if (length > 0) {
 1412 restartsync:
 1413                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1414                         if (bp->b_lblkno > 0)
 1415                                 continue;
 1416                         /*
 1417                          * Since we hold the vnode lock this should only
 1418                          * fail if we're racing with the buf daemon.
 1419                          */
 1420                         if (BUF_LOCK(bp,
 1421                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1422                             BO_MTX(bo)) == ENOLCK) {
 1423                                 goto restart;
 1424                         }
 1425                         VNASSERT((bp->b_flags & B_DELWRI), vp,
 1426                             ("buf(%p) on dirty queue without DELWRI", bp));
 1427 
 1428                         BO_LOCK(bo);
 1429                         bremfree(bp);
 1430                         BO_UNLOCK(bo);
 1431                         bawrite(bp);
 1432                         BO_LOCK(bo);
 1433                         goto restartsync;
 1434                 }
 1435         }
 1436 
 1437         bufobj_wwait(bo, 0, 0);
 1438         BO_UNLOCK(bo);
 1439         vnode_pager_setsize(vp, length);
 1440 
 1441         return (0);
 1442 }
 1443 
 1444 /*
 1445  * buf_splay() - splay tree core for the clean/dirty list of buffers in
 1446  *               a vnode.
 1447  *
 1448  *      NOTE: We have to deal with the special case of a background bitmap
 1449  *      buffer, a situation where two buffers will have the same logical
 1450  *      block offset.  We want (1) only the foreground buffer to be accessed
 1451  *      in a lookup and (2) must differentiate between the foreground and
 1452  *      background buffer in the splay tree algorithm because the splay
 1453  *      tree cannot normally handle multiple entities with the same 'index'.
 1454  *      We accomplish this by adding differentiating flags to the splay tree's
 1455  *      numerical domain.
 1456  */
 1457 static
 1458 struct buf *
 1459 buf_splay(daddr_t lblkno, b_xflags_t xflags, struct buf *root)
 1460 {
 1461         struct buf dummy;
 1462         struct buf *lefttreemax, *righttreemin, *y;
 1463 
 1464         if (root == NULL)
 1465                 return (NULL);
 1466         lefttreemax = righttreemin = &dummy;
 1467         for (;;) {
 1468                 if (lblkno < root->b_lblkno ||
 1469                     (lblkno == root->b_lblkno &&
 1470                     (xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1471                         if ((y = root->b_left) == NULL)
 1472                                 break;
 1473                         if (lblkno < y->b_lblkno) {
 1474                                 /* Rotate right. */
 1475                                 root->b_left = y->b_right;
 1476                                 y->b_right = root;
 1477                                 root = y;
 1478                                 if ((y = root->b_left) == NULL)
 1479                                         break;
 1480                         }
 1481                         /* Link into the new root's right tree. */
 1482                         righttreemin->b_left = root;
 1483                         righttreemin = root;
 1484                 } else if (lblkno > root->b_lblkno ||
 1485                     (lblkno == root->b_lblkno &&
 1486                     (xflags & BX_BKGRDMARKER) > (root->b_xflags & BX_BKGRDMARKER))) {
 1487                         if ((y = root->b_right) == NULL)
 1488                                 break;
 1489                         if (lblkno > y->b_lblkno) {
 1490                                 /* Rotate left. */
 1491                                 root->b_right = y->b_left;
 1492                                 y->b_left = root;
 1493                                 root = y;
 1494                                 if ((y = root->b_right) == NULL)
 1495                                         break;
 1496                         }
 1497                         /* Link into the new root's left tree. */
 1498                         lefttreemax->b_right = root;
 1499                         lefttreemax = root;
 1500                 } else {
 1501                         break;
 1502                 }
 1503                 root = y;
 1504         }
 1505         /* Assemble the new root. */
 1506         lefttreemax->b_right = root->b_left;
 1507         righttreemin->b_left = root->b_right;
 1508         root->b_left = dummy.b_right;
 1509         root->b_right = dummy.b_left;
 1510         return (root);
 1511 }
 1512 
 1513 static void
 1514 buf_vlist_remove(struct buf *bp)
 1515 {
 1516         struct buf *root;
 1517         struct bufv *bv;
 1518 
 1519         KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
 1520         ASSERT_BO_LOCKED(bp->b_bufobj);
 1521         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) !=
 1522             (BX_VNDIRTY|BX_VNCLEAN),
 1523             ("buf_vlist_remove: Buf %p is on two lists", bp));
 1524         if (bp->b_xflags & BX_VNDIRTY)
 1525                 bv = &bp->b_bufobj->bo_dirty;
 1526         else
 1527                 bv = &bp->b_bufobj->bo_clean;
 1528         if (bp != bv->bv_root) {
 1529                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1530                 KASSERT(root == bp, ("splay lookup failed in remove"));
 1531         }
 1532         if (bp->b_left == NULL) {
 1533                 root = bp->b_right;
 1534         } else {
 1535                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
 1536                 root->b_right = bp->b_right;
 1537         }
 1538         bv->bv_root = root;
 1539         TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
 1540         bv->bv_cnt--;
 1541         bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
 1542 }
 1543 
 1544 /*
 1545  * Add the buffer to the sorted clean or dirty block list using a
 1546  * splay tree algorithm.
 1547  *
 1548  * NOTE: xflags is passed as a constant, optimizing this inline function!
 1549  */
 1550 static void
 1551 buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
 1552 {
 1553         struct buf *root;
 1554         struct bufv *bv;
 1555 
 1556         ASSERT_BO_LOCKED(bo);
 1557         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
 1558             ("buf_vlist_add: Buf %p has existing xflags %d", bp, bp->b_xflags));
 1559         bp->b_xflags |= xflags;
 1560         if (xflags & BX_VNDIRTY)
 1561                 bv = &bo->bo_dirty;
 1562         else
 1563                 bv = &bo->bo_clean;
 1564 
 1565         root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1566         if (root == NULL) {
 1567                 bp->b_left = NULL;
 1568                 bp->b_right = NULL;
 1569                 TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
 1570         } else if (bp->b_lblkno < root->b_lblkno ||
 1571             (bp->b_lblkno == root->b_lblkno &&
 1572             (bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1573                 bp->b_left = root->b_left;
 1574                 bp->b_right = root;
 1575                 root->b_left = NULL;
 1576                 TAILQ_INSERT_BEFORE(root, bp, b_bobufs);
 1577         } else {
 1578                 bp->b_right = root->b_right;
 1579                 bp->b_left = root;
 1580                 root->b_right = NULL;
 1581                 TAILQ_INSERT_AFTER(&bv->bv_hd, root, bp, b_bobufs);
 1582         }
 1583         bv->bv_cnt++;
 1584         bv->bv_root = bp;
 1585 }
 1586 
 1587 /*
 1588  * Lookup a buffer using the splay tree.  Note that we specifically avoid
 1589  * shadow buffers used in background bitmap writes.
 1590  *
 1591  * This code isn't quite efficient as it could be because we are maintaining
 1592  * two sorted lists and do not know which list the block resides in.
 1593  *
 1594  * During a "make buildworld" the desired buffer is found at one of
 1595  * the roots more than 60% of the time.  Thus, checking both roots
 1596  * before performing either splay eliminates unnecessary splays on the
 1597  * first tree splayed.
 1598  */
 1599 struct buf *
 1600 gbincore(struct bufobj *bo, daddr_t lblkno)
 1601 {
 1602         struct buf *bp;
 1603 
 1604         ASSERT_BO_LOCKED(bo);
 1605         if ((bp = bo->bo_clean.bv_root) != NULL &&
 1606             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1607                 return (bp);
 1608         if ((bp = bo->bo_dirty.bv_root) != NULL &&
 1609             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1610                 return (bp);
 1611         if ((bp = bo->bo_clean.bv_root) != NULL) {
 1612                 bo->bo_clean.bv_root = bp = buf_splay(lblkno, 0, bp);
 1613                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1614                         return (bp);
 1615         }
 1616         if ((bp = bo->bo_dirty.bv_root) != NULL) {
 1617                 bo->bo_dirty.bv_root = bp = buf_splay(lblkno, 0, bp);
 1618                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1619                         return (bp);
 1620         }
 1621         return (NULL);
 1622 }
 1623 
 1624 /*
 1625  * Associate a buffer with a vnode.
 1626  */
 1627 void
 1628 bgetvp(struct vnode *vp, struct buf *bp)
 1629 {
 1630         struct bufobj *bo;
 1631 
 1632         bo = &vp->v_bufobj;
 1633         ASSERT_BO_LOCKED(bo);
 1634         VNASSERT(bp->b_vp == NULL, bp->b_vp, ("bgetvp: not free"));
 1635 
 1636         CTR3(KTR_BUF, "bgetvp(%p) vp %p flags %X", bp, vp, bp->b_flags);
 1637         VNASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0, vp,
 1638             ("bgetvp: bp already attached! %p", bp));
 1639 
 1640         vhold(vp);
 1641         if (VFS_NEEDSGIANT(vp->v_mount) || bo->bo_flag & BO_NEEDSGIANT)
 1642                 bp->b_flags |= B_NEEDSGIANT;
 1643         bp->b_vp = vp;
 1644         bp->b_bufobj = bo;
 1645         /*
 1646          * Insert onto list for new vnode.
 1647          */
 1648         buf_vlist_add(bp, bo, BX_VNCLEAN);
 1649 }
 1650 
 1651 /*
 1652  * Disassociate a buffer from a vnode.
 1653  */
 1654 void
 1655 brelvp(struct buf *bp)
 1656 {
 1657         struct bufobj *bo;
 1658         struct vnode *vp;
 1659 
 1660         CTR3(KTR_BUF, "brelvp(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
 1661         KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
 1662 
 1663         /*
 1664          * Delete from old vnode list, if on one.
 1665          */
 1666         vp = bp->b_vp;          /* XXX */
 1667         bo = bp->b_bufobj;
 1668         BO_LOCK(bo);
 1669         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1670                 buf_vlist_remove(bp);
 1671         else
 1672                 panic("brelvp: Buffer %p not on queue.", bp);
 1673         if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 1674                 bo->bo_flag &= ~BO_ONWORKLST;
 1675                 mtx_lock(&sync_mtx);
 1676                 LIST_REMOVE(bo, bo_synclist);
 1677                 syncer_worklist_len--;
 1678                 mtx_unlock(&sync_mtx);
 1679         }
 1680         bp->b_flags &= ~B_NEEDSGIANT;
 1681         bp->b_vp = NULL;
 1682         bp->b_bufobj = NULL;
 1683         BO_UNLOCK(bo);
 1684         vdrop(vp);
 1685 }
 1686 
 1687 /*
 1688  * Add an item to the syncer work queue.
 1689  */
 1690 static void
 1691 vn_syncer_add_to_worklist(struct bufobj *bo, int delay)
 1692 {
 1693         int queue, slot;
 1694 
 1695         ASSERT_BO_LOCKED(bo);
 1696 
 1697         mtx_lock(&sync_mtx);
 1698         if (bo->bo_flag & BO_ONWORKLST)
 1699                 LIST_REMOVE(bo, bo_synclist);
 1700         else {
 1701                 bo->bo_flag |= BO_ONWORKLST;
 1702                 syncer_worklist_len++;
 1703         }
 1704 
 1705         if (delay > syncer_maxdelay - 2)
 1706                 delay = syncer_maxdelay - 2;
 1707         slot = (syncer_delayno + delay) & syncer_mask;
 1708 
 1709         queue = VFS_NEEDSGIANT(bo->__bo_vnode->v_mount) ? WI_GIANTQ :
 1710             WI_MPSAFEQ;
 1711         LIST_INSERT_HEAD(&syncer_workitem_pending[queue][slot], bo,
 1712             bo_synclist);
 1713         mtx_unlock(&sync_mtx);
 1714 }
 1715 
 1716 static int
 1717 sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
 1718 {
 1719         int error, len;
 1720 
 1721         mtx_lock(&sync_mtx);
 1722         len = syncer_worklist_len - sync_vnode_count;
 1723         mtx_unlock(&sync_mtx);
 1724         error = SYSCTL_OUT(req, &len, sizeof(len));
 1725         return (error);
 1726 }
 1727 
 1728 SYSCTL_PROC(_vfs, OID_AUTO, worklist_len, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
 1729     sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
 1730 
 1731 static struct proc *updateproc;
 1732 static void sched_sync(void);
 1733 static struct kproc_desc up_kp = {
 1734         "syncer",
 1735         sched_sync,
 1736         &updateproc
 1737 };
 1738 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp);
 1739 
 1740 static int
 1741 sync_vnode(struct synclist *slp, struct bufobj **bo, struct thread *td)
 1742 {
 1743         struct vnode *vp;
 1744         struct mount *mp;
 1745 
 1746         *bo = LIST_FIRST(slp);
 1747         if (*bo == NULL)
 1748                 return (0);
 1749         vp = (*bo)->__bo_vnode; /* XXX */
 1750         if (VOP_ISLOCKED(vp) != 0 || VI_TRYLOCK(vp) == 0)
 1751                 return (1);
 1752         /*
 1753          * We use vhold in case the vnode does not
 1754          * successfully sync.  vhold prevents the vnode from
 1755          * going away when we unlock the sync_mtx so that
 1756          * we can acquire the vnode interlock.
 1757          */
 1758         vholdl(vp);
 1759         mtx_unlock(&sync_mtx);
 1760         VI_UNLOCK(vp);
 1761         if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
 1762                 vdrop(vp);
 1763                 mtx_lock(&sync_mtx);
 1764                 return (*bo == LIST_FIRST(slp));
 1765         }
 1766         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1767         (void) VOP_FSYNC(vp, MNT_LAZY, td);
 1768         VOP_UNLOCK(vp, 0);
 1769         vn_finished_write(mp);
 1770         BO_LOCK(*bo);
 1771         if (((*bo)->bo_flag & BO_ONWORKLST) != 0) {
 1772                 /*
 1773                  * Put us back on the worklist.  The worklist
 1774                  * routine will remove us from our current
 1775                  * position and then add us back in at a later
 1776                  * position.
 1777                  */
 1778                 vn_syncer_add_to_worklist(*bo, syncdelay);
 1779         }
 1780         BO_UNLOCK(*bo);
 1781         vdrop(vp);
 1782         mtx_lock(&sync_mtx);
 1783         return (0);
 1784 }
 1785 
 1786 /*
 1787  * System filesystem synchronizer daemon.
 1788  */
 1789 static void
 1790 sched_sync(void)
 1791 {
 1792         struct synclist *gnext, *next;
 1793         struct synclist *gslp, *slp;
 1794         struct bufobj *bo;
 1795         long starttime;
 1796         struct thread *td = curthread;
 1797         int last_work_seen;
 1798         int net_worklist_len;
 1799         int syncer_final_iter;
 1800         int first_printf;
 1801         int error;
 1802 
 1803         last_work_seen = 0;
 1804         syncer_final_iter = 0;
 1805         first_printf = 1;
 1806         syncer_state = SYNCER_RUNNING;
 1807         starttime = time_uptime;
 1808         td->td_pflags |= TDP_NORUNNINGBUF;
 1809 
 1810         EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
 1811             SHUTDOWN_PRI_LAST);
 1812 
 1813         mtx_lock(&sync_mtx);
 1814         for (;;) {
 1815                 if (syncer_state == SYNCER_FINAL_DELAY &&
 1816                     syncer_final_iter == 0) {
 1817                         mtx_unlock(&sync_mtx);
 1818                         kproc_suspend_check(td->td_proc);
 1819                         mtx_lock(&sync_mtx);
 1820                 }
 1821                 net_worklist_len = syncer_worklist_len - sync_vnode_count;
 1822                 if (syncer_state != SYNCER_RUNNING &&
 1823                     starttime != time_uptime) {
 1824                         if (first_printf) {
 1825                                 printf("\nSyncing disks, vnodes remaining...");
 1826                                 first_printf = 0;
 1827                         }
 1828                         printf("%d ", net_worklist_len);
 1829                 }
 1830                 starttime = time_uptime;
 1831 
 1832                 /*
 1833                  * Push files whose dirty time has expired.  Be careful
 1834                  * of interrupt race on slp queue.
 1835                  *
 1836                  * Skip over empty worklist slots when shutting down.
 1837                  */
 1838                 do {
 1839                         slp = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1840                         gslp = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1841                         syncer_delayno += 1;
 1842                         if (syncer_delayno == syncer_maxdelay)
 1843                                 syncer_delayno = 0;
 1844                         next = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1845                         gnext = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1846                         /*
 1847                          * If the worklist has wrapped since the
 1848                          * it was emptied of all but syncer vnodes,
 1849                          * switch to the FINAL_DELAY state and run
 1850                          * for one more second.
 1851                          */
 1852                         if (syncer_state == SYNCER_SHUTTING_DOWN &&
 1853                             net_worklist_len == 0 &&
 1854                             last_work_seen == syncer_delayno) {
 1855                                 syncer_state = SYNCER_FINAL_DELAY;
 1856                                 syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
 1857                         }
 1858                 } while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
 1859                     LIST_EMPTY(gslp) && syncer_worklist_len > 0);
 1860 
 1861                 /*
 1862                  * Keep track of the last time there was anything
 1863                  * on the worklist other than syncer vnodes.
 1864                  * Return to the SHUTTING_DOWN state if any
 1865                  * new work appears.
 1866                  */
 1867                 if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
 1868                         last_work_seen = syncer_delayno;
 1869                 if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
 1870                         syncer_state = SYNCER_SHUTTING_DOWN;
 1871                 while (!LIST_EMPTY(slp)) {
 1872                         error = sync_vnode(slp, &bo, td);
 1873                         if (error == 1) {
 1874                                 LIST_REMOVE(bo, bo_synclist);
 1875                                 LIST_INSERT_HEAD(next, bo, bo_synclist);
 1876                                 continue;
 1877                         }
 1878 #ifdef SW_WATCHDOG
 1879                         if (first_printf == 0)
 1880                                 wdog_kern_pat(WD_LASTVAL);
 1881 #endif
 1882                 }
 1883                 if (!LIST_EMPTY(gslp)) {
 1884                         mtx_unlock(&sync_mtx);
 1885                         mtx_lock(&Giant);
 1886                         mtx_lock(&sync_mtx);
 1887                         while (!LIST_EMPTY(gslp)) {
 1888                                 error = sync_vnode(gslp, &bo, td);
 1889                                 if (error == 1) {
 1890                                         LIST_REMOVE(bo, bo_synclist);
 1891                                         LIST_INSERT_HEAD(gnext, bo,
 1892                                             bo_synclist);
 1893                                         continue;
 1894                                 }
 1895                         }
 1896                         mtx_unlock(&Giant);
 1897                 }
 1898                 if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
 1899                         syncer_final_iter--;
 1900                 /*
 1901                  * The variable rushjob allows the kernel to speed up the
 1902                  * processing of the filesystem syncer process. A rushjob
 1903                  * value of N tells the filesystem syncer to process the next
 1904                  * N seconds worth of work on its queue ASAP. Currently rushjob
 1905                  * is used by the soft update code to speed up the filesystem
 1906                  * syncer process when the incore state is getting so far
 1907                  * ahead of the disk that the kernel memory pool is being
 1908                  * threatened with exhaustion.
 1909                  */
 1910                 if (rushjob > 0) {
 1911                         rushjob -= 1;
 1912                         continue;
 1913                 }
 1914                 /*
 1915                  * Just sleep for a short period of time between
 1916                  * iterations when shutting down to allow some I/O
 1917                  * to happen.
 1918                  *
 1919                  * If it has taken us less than a second to process the
 1920                  * current work, then wait. Otherwise start right over
 1921                  * again. We can still lose time if any single round
 1922                  * takes more than two seconds, but it does not really
 1923                  * matter as we are just trying to generally pace the
 1924                  * filesystem activity.
 1925                  */
 1926                 if (syncer_state != SYNCER_RUNNING ||
 1927                     time_uptime == starttime) {
 1928                         thread_lock(td);
 1929                         sched_prio(td, PPAUSE);
 1930                         thread_unlock(td);
 1931                 }
 1932                 if (syncer_state != SYNCER_RUNNING)
 1933                         cv_timedwait(&sync_wakeup, &sync_mtx,
 1934                             hz / SYNCER_SHUTDOWN_SPEEDUP);
 1935                 else if (time_uptime == starttime)
 1936                         cv_timedwait(&sync_wakeup, &sync_mtx, hz);
 1937         }
 1938 }
 1939 
 1940 /*
 1941  * Request the syncer daemon to speed up its work.
 1942  * We never push it to speed up more than half of its
 1943  * normal turn time, otherwise it could take over the cpu.
 1944  */
 1945 int
 1946 speedup_syncer(void)
 1947 {
 1948         int ret = 0;
 1949 
 1950         mtx_lock(&sync_mtx);
 1951         if (rushjob < syncdelay / 2) {
 1952                 rushjob += 1;
 1953                 stat_rush_requests += 1;
 1954                 ret = 1;
 1955         }
 1956         mtx_unlock(&sync_mtx);
 1957         cv_broadcast(&sync_wakeup);
 1958         return (ret);
 1959 }
 1960 
 1961 /*
 1962  * Tell the syncer to speed up its work and run though its work
 1963  * list several times, then tell it to shut down.
 1964  */
 1965 static void
 1966 syncer_shutdown(void *arg, int howto)
 1967 {
 1968 
 1969         if (howto & RB_NOSYNC)
 1970                 return;
 1971         mtx_lock(&sync_mtx);
 1972         syncer_state = SYNCER_SHUTTING_DOWN;
 1973         rushjob = 0;
 1974         mtx_unlock(&sync_mtx);
 1975         cv_broadcast(&sync_wakeup);
 1976         kproc_shutdown(arg, howto);
 1977 }
 1978 
 1979 /*
 1980  * Reassign a buffer from one vnode to another.
 1981  * Used to assign file specific control information
 1982  * (indirect blocks) to the vnode to which they belong.
 1983  */
 1984 void
 1985 reassignbuf(struct buf *bp)
 1986 {
 1987         struct vnode *vp;
 1988         struct bufobj *bo;
 1989         int delay;
 1990 #ifdef INVARIANTS
 1991         struct bufv *bv;
 1992 #endif
 1993 
 1994         vp = bp->b_vp;
 1995         bo = bp->b_bufobj;
 1996         ++reassignbufcalls;
 1997 
 1998         CTR3(KTR_BUF, "reassignbuf(%p) vp %p flags %X",
 1999             bp, bp->b_vp, bp->b_flags);
 2000         /*
 2001          * B_PAGING flagged buffers cannot be reassigned because their vp
 2002          * is not fully linked in.
 2003          */
 2004         if (bp->b_flags & B_PAGING)
 2005                 panic("cannot reassign paging buffer");
 2006 
 2007         /*
 2008          * Delete from old vnode list, if on one.
 2009          */
 2010         BO_LOCK(bo);
 2011         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 2012                 buf_vlist_remove(bp);
 2013         else
 2014                 panic("reassignbuf: Buffer %p not on queue.", bp);
 2015         /*
 2016          * If dirty, put on list of dirty buffers; otherwise insert onto list
 2017          * of clean buffers.
 2018          */
 2019         if (bp->b_flags & B_DELWRI) {
 2020                 if ((bo->bo_flag & BO_ONWORKLST) == 0) {
 2021                         switch (vp->v_type) {
 2022                         case VDIR:
 2023                                 delay = dirdelay;
 2024                                 break;
 2025                         case VCHR:
 2026                                 delay = metadelay;
 2027                                 break;
 2028                         default:
 2029                                 delay = filedelay;
 2030                         }
 2031                         vn_syncer_add_to_worklist(bo, delay);
 2032                 }
 2033                 buf_vlist_add(bp, bo, BX_VNDIRTY);
 2034         } else {
 2035                 buf_vlist_add(bp, bo, BX_VNCLEAN);
 2036 
 2037                 if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 2038                         mtx_lock(&sync_mtx);
 2039                         LIST_REMOVE(bo, bo_synclist);
 2040                         syncer_worklist_len--;
 2041                         mtx_unlock(&sync_mtx);
 2042                         bo->bo_flag &= ~BO_ONWORKLST;
 2043                 }
 2044         }
 2045 #ifdef INVARIANTS
 2046         bv = &bo->bo_clean;
 2047         bp = TAILQ_FIRST(&bv->bv_hd);
 2048         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2049             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2050         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 2051         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2052             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2053         bv = &bo->bo_dirty;
 2054         bp = TAILQ_FIRST(&bv->bv_hd);
 2055         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2056             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2057         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 2058         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2059             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2060 #endif
 2061         BO_UNLOCK(bo);
 2062 }
 2063 
 2064 /*
 2065  * Increment the use and hold counts on the vnode, taking care to reference
 2066  * the driver's usecount if this is a chardev.  The vholdl() will remove
 2067  * the vnode from the free list if it is presently free.  Requires the
 2068  * vnode interlock and returns with it held.
 2069  */
 2070 static void
 2071 v_incr_usecount(struct vnode *vp)
 2072 {
 2073 
 2074         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2075         vp->v_usecount++;
 2076         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2077                 dev_lock();
 2078                 vp->v_rdev->si_usecount++;
 2079                 dev_unlock();
 2080         }
 2081         vholdl(vp);
 2082 }
 2083 
 2084 /*
 2085  * Turn a holdcnt into a use+holdcnt such that only one call to
 2086  * v_decr_usecount is needed.
 2087  */
 2088 static void
 2089 v_upgrade_usecount(struct vnode *vp)
 2090 {
 2091 
 2092         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2093         vp->v_usecount++;
 2094         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2095                 dev_lock();
 2096                 vp->v_rdev->si_usecount++;
 2097                 dev_unlock();
 2098         }
 2099 }
 2100 
 2101 /*
 2102  * Decrement the vnode use and hold count along with the driver's usecount
 2103  * if this is a chardev.  The vdropl() below releases the vnode interlock
 2104  * as it may free the vnode.
 2105  */
 2106 static void
 2107 v_decr_usecount(struct vnode *vp)
 2108 {
 2109 
 2110         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2111         VNASSERT(vp->v_usecount > 0, vp,
 2112             ("v_decr_usecount: negative usecount"));
 2113         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2114         vp->v_usecount--;
 2115         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2116                 dev_lock();
 2117                 vp->v_rdev->si_usecount--;
 2118                 dev_unlock();
 2119         }
 2120         vdropl(vp);
 2121 }
 2122 
 2123 /*
 2124  * Decrement only the use count and driver use count.  This is intended to
 2125  * be paired with a follow on vdropl() to release the remaining hold count.
 2126  * In this way we may vgone() a vnode with a 0 usecount without risk of
 2127  * having it end up on a free list because the hold count is kept above 0.
 2128  */
 2129 static void
 2130 v_decr_useonly(struct vnode *vp)
 2131 {
 2132 
 2133         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2134         VNASSERT(vp->v_usecount > 0, vp,
 2135             ("v_decr_useonly: negative usecount"));
 2136         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2137         vp->v_usecount--;
 2138         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2139                 dev_lock();
 2140                 vp->v_rdev->si_usecount--;
 2141                 dev_unlock();
 2142         }
 2143 }
 2144 
 2145 /*
 2146  * Grab a particular vnode from the free list, increment its
 2147  * reference count and lock it.  VI_DOOMED is set if the vnode
 2148  * is being destroyed.  Only callers who specify LK_RETRY will
 2149  * see doomed vnodes.  If inactive processing was delayed in
 2150  * vput try to do it here.
 2151  */
 2152 int
 2153 vget(struct vnode *vp, int flags, struct thread *td)
 2154 {
 2155         int error;
 2156 
 2157         error = 0;
 2158         VFS_ASSERT_GIANT(vp->v_mount);
 2159         VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
 2160             ("vget: invalid lock operation"));
 2161         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 2162 
 2163         if ((flags & LK_INTERLOCK) == 0)
 2164                 VI_LOCK(vp);
 2165         vholdl(vp);
 2166         if ((error = vn_lock(vp, flags | LK_INTERLOCK)) != 0) {
 2167                 vdrop(vp);
 2168                 CTR2(KTR_VFS, "%s: impossible to lock vnode %p", __func__,
 2169                     vp);
 2170                 return (error);
 2171         }
 2172         if (vp->v_iflag & VI_DOOMED && (flags & LK_RETRY) == 0)
 2173                 panic("vget: vn_lock failed to return ENOENT\n");
 2174         VI_LOCK(vp);
 2175         /* Upgrade our holdcnt to a usecount. */
 2176         v_upgrade_usecount(vp);
 2177         /*
 2178          * We don't guarantee that any particular close will
 2179          * trigger inactive processing so just make a best effort
 2180          * here at preventing a reference to a removed file.  If
 2181          * we don't succeed no harm is done.
 2182          */
 2183         if (vp->v_iflag & VI_OWEINACT) {
 2184                 if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE &&
 2185                     (flags & LK_NOWAIT) == 0)
 2186                         vinactive(vp, td);
 2187                 vp->v_iflag &= ~VI_OWEINACT;
 2188         }
 2189         VI_UNLOCK(vp);
 2190         return (0);
 2191 }
 2192 
 2193 /*
 2194  * Increase the reference count of a vnode.
 2195  */
 2196 void
 2197 vref(struct vnode *vp)
 2198 {
 2199 
 2200         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2201         VI_LOCK(vp);
 2202         v_incr_usecount(vp);
 2203         VI_UNLOCK(vp);
 2204 }
 2205 
 2206 /*
 2207  * Return reference count of a vnode.
 2208  *
 2209  * The results of this call are only guaranteed when some mechanism other
 2210  * than the VI lock is used to stop other processes from gaining references
 2211  * to the vnode.  This may be the case if the caller holds the only reference.
 2212  * This is also useful when stale data is acceptable as race conditions may
 2213  * be accounted for by some other means.
 2214  */
 2215 int
 2216 vrefcnt(struct vnode *vp)
 2217 {
 2218         int usecnt;
 2219 
 2220         VI_LOCK(vp);
 2221         usecnt = vp->v_usecount;
 2222         VI_UNLOCK(vp);
 2223 
 2224         return (usecnt);
 2225 }
 2226 
 2227 #define VPUTX_VRELE     1
 2228 #define VPUTX_VPUT      2
 2229 #define VPUTX_VUNREF    3
 2230 
 2231 static void
 2232 vputx(struct vnode *vp, int func)
 2233 {
 2234         int error;
 2235 
 2236         KASSERT(vp != NULL, ("vputx: null vp"));
 2237         if (func == VPUTX_VUNREF)
 2238                 ASSERT_VOP_LOCKED(vp, "vunref");
 2239         else if (func == VPUTX_VPUT)
 2240                 ASSERT_VOP_LOCKED(vp, "vput");
 2241         else
 2242                 KASSERT(func == VPUTX_VRELE, ("vputx: wrong func"));
 2243         VFS_ASSERT_GIANT(vp->v_mount);
 2244         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2245         VI_LOCK(vp);
 2246 
 2247         /* Skip this v_writecount check if we're going to panic below. */
 2248         VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
 2249             ("vputx: missed vn_close"));
 2250         error = 0;
 2251 
 2252         if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
 2253             vp->v_usecount == 1)) {
 2254                 if (func == VPUTX_VPUT)
 2255                         VOP_UNLOCK(vp, 0);
 2256                 v_decr_usecount(vp);
 2257                 return;
 2258         }
 2259 
 2260         if (vp->v_usecount != 1) {
 2261                 vprint("vputx: negative ref count", vp);
 2262                 panic("vputx: negative ref cnt");
 2263         }
 2264         CTR2(KTR_VFS, "%s: return vnode %p to the freelist", __func__, vp);
 2265         /*
 2266          * We want to hold the vnode until the inactive finishes to
 2267          * prevent vgone() races.  We drop the use count here and the
 2268          * hold count below when we're done.
 2269          */
 2270         v_decr_useonly(vp);
 2271         /*
 2272          * We must call VOP_INACTIVE with the node locked. Mark
 2273          * as VI_DOINGINACT to avoid recursion.
 2274          */
 2275         vp->v_iflag |= VI_OWEINACT;
 2276         switch (func) {
 2277         case VPUTX_VRELE:
 2278                 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK);
 2279                 VI_LOCK(vp);
 2280                 break;
 2281         case VPUTX_VPUT:
 2282                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
 2283                         error = VOP_LOCK(vp, LK_UPGRADE | LK_INTERLOCK |
 2284                             LK_NOWAIT);
 2285                         VI_LOCK(vp);
 2286                 }
 2287                 break;
 2288         case VPUTX_VUNREF:
 2289                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 2290                         error = EBUSY;
 2291                 break;
 2292         }
 2293         if (vp->v_usecount > 0)
 2294                 vp->v_iflag &= ~VI_OWEINACT;
 2295         if (error == 0) {
 2296                 if (vp->v_iflag & VI_OWEINACT)
 2297                         vinactive(vp, curthread);
 2298                 if (func != VPUTX_VUNREF)
 2299                         VOP_UNLOCK(vp, 0);
 2300         }
 2301         vdropl(vp);
 2302 }
 2303 
 2304 /*
 2305  * Vnode put/release.
 2306  * If count drops to zero, call inactive routine and return to freelist.
 2307  */
 2308 void
 2309 vrele(struct vnode *vp)
 2310 {
 2311 
 2312         vputx(vp, VPUTX_VRELE);
 2313 }
 2314 
 2315 /*
 2316  * Release an already locked vnode.  This give the same effects as
 2317  * unlock+vrele(), but takes less time and avoids releasing and
 2318  * re-aquiring the lock (as vrele() acquires the lock internally.)
 2319  */
 2320 void
 2321 vput(struct vnode *vp)
 2322 {
 2323 
 2324         vputx(vp, VPUTX_VPUT);
 2325 }
 2326 
 2327 /*
 2328  * Release an exclusively locked vnode. Do not unlock the vnode lock.
 2329  */
 2330 void
 2331 vunref(struct vnode *vp)
 2332 {
 2333 
 2334         vputx(vp, VPUTX_VUNREF);
 2335 }
 2336 
 2337 /*
 2338  * Somebody doesn't want the vnode recycled.
 2339  */
 2340 void
 2341 vhold(struct vnode *vp)
 2342 {
 2343 
 2344         VI_LOCK(vp);
 2345         vholdl(vp);
 2346         VI_UNLOCK(vp);
 2347 }
 2348 
 2349 void
 2350 vholdl(struct vnode *vp)
 2351 {
 2352 
 2353         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2354         vp->v_holdcnt++;
 2355         if (VSHOULDBUSY(vp))
 2356                 vbusy(vp);
 2357 }
 2358 
 2359 /*
 2360  * Note that there is one less who cares about this vnode.  vdrop() is the
 2361  * opposite of vhold().
 2362  */
 2363 void
 2364 vdrop(struct vnode *vp)
 2365 {
 2366 
 2367         VI_LOCK(vp);
 2368         vdropl(vp);
 2369 }
 2370 
 2371 /*
 2372  * Drop the hold count of the vnode.  If this is the last reference to
 2373  * the vnode we will free it if it has been vgone'd otherwise it is
 2374  * placed on the free list.
 2375  */
 2376 void
 2377 vdropl(struct vnode *vp)
 2378 {
 2379 
 2380         ASSERT_VI_LOCKED(vp, "vdropl");
 2381         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2382         if (vp->v_holdcnt <= 0)
 2383                 panic("vdrop: holdcnt %d", vp->v_holdcnt);
 2384         vp->v_holdcnt--;
 2385         if (vp->v_holdcnt == 0) {
 2386                 if (vp->v_iflag & VI_DOOMED) {
 2387                         CTR2(KTR_VFS, "%s: destroying the vnode %p", __func__,
 2388                             vp);
 2389                         vdestroy(vp);
 2390                         return;
 2391                 } else
 2392                         vfree(vp);
 2393         }
 2394         VI_UNLOCK(vp);
 2395 }
 2396 
 2397 /*
 2398  * Call VOP_INACTIVE on the vnode and manage the DOINGINACT and OWEINACT
 2399  * flags.  DOINGINACT prevents us from recursing in calls to vinactive.
 2400  * OWEINACT tracks whether a vnode missed a call to inactive due to a
 2401  * failed lock upgrade.
 2402  */
 2403 static void
 2404 vinactive(struct vnode *vp, struct thread *td)
 2405 {
 2406 
 2407         ASSERT_VOP_ELOCKED(vp, "vinactive");
 2408         ASSERT_VI_LOCKED(vp, "vinactive");
 2409         VNASSERT((vp->v_iflag & VI_DOINGINACT) == 0, vp,
 2410             ("vinactive: recursed on VI_DOINGINACT"));
 2411         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2412         vp->v_iflag |= VI_DOINGINACT;
 2413         vp->v_iflag &= ~VI_OWEINACT;
 2414         VI_UNLOCK(vp);
 2415         VOP_INACTIVE(vp, td);
 2416         VI_LOCK(vp);
 2417         VNASSERT(vp->v_iflag & VI_DOINGINACT, vp,
 2418             ("vinactive: lost VI_DOINGINACT"));
 2419         vp->v_iflag &= ~VI_DOINGINACT;
 2420 }
 2421 
 2422 /*
 2423  * Remove any vnodes in the vnode table belonging to mount point mp.
 2424  *
 2425  * If FORCECLOSE is not specified, there should not be any active ones,
 2426  * return error if any are found (nb: this is a user error, not a
 2427  * system error). If FORCECLOSE is specified, detach any active vnodes
 2428  * that are found.
 2429  *
 2430  * If WRITECLOSE is set, only flush out regular file vnodes open for
 2431  * writing.
 2432  *
 2433  * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
 2434  *
 2435  * `rootrefs' specifies the base reference count for the root vnode
 2436  * of this filesystem. The root vnode is considered busy if its
 2437  * v_usecount exceeds this value. On a successful return, vflush(, td)
 2438  * will call vrele() on the root vnode exactly rootrefs times.
 2439  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
 2440  * be zero.
 2441  */
 2442 #ifdef DIAGNOSTIC
 2443 static int busyprt = 0;         /* print out busy vnodes */
 2444 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "Print out busy vnodes");
 2445 #endif
 2446 
 2447 int
 2448 vflush(struct mount *mp, int rootrefs, int flags, struct thread *td)
 2449 {
 2450         struct vnode *vp, *mvp, *rootvp = NULL;
 2451         struct vattr vattr;
 2452         int busy = 0, error;
 2453 
 2454         CTR4(KTR_VFS, "%s: mp %p with rootrefs %d and flags %d", __func__, mp,
 2455             rootrefs, flags);
 2456         if (rootrefs > 0) {
 2457                 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
 2458                     ("vflush: bad args"));
 2459                 /*
 2460                  * Get the filesystem root vnode. We can vput() it
 2461                  * immediately, since with rootrefs > 0, it won't go away.
 2462                  */
 2463                 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rootvp)) != 0) {
 2464                         CTR2(KTR_VFS, "%s: vfs_root lookup failed with %d",
 2465                             __func__, error);
 2466                         return (error);
 2467                 }
 2468                 vput(rootvp);
 2469         }
 2470         MNT_ILOCK(mp);
 2471 loop:
 2472         MNT_VNODE_FOREACH(vp, mp, mvp) {
 2473                 VI_LOCK(vp);
 2474                 vholdl(vp);
 2475                 MNT_IUNLOCK(mp);
 2476                 error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE);
 2477                 if (error) {
 2478                         vdrop(vp);
 2479                         MNT_ILOCK(mp);
 2480                         MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);
 2481                         goto loop;
 2482                 }
 2483                 /*
 2484                  * Skip over a vnodes marked VV_SYSTEM.
 2485                  */
 2486                 if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
 2487                         VOP_UNLOCK(vp, 0);
 2488                         vdrop(vp);
 2489                         MNT_ILOCK(mp);
 2490                         continue;
 2491                 }
 2492                 /*
 2493                  * If WRITECLOSE is set, flush out unlinked but still open
 2494                  * files (even if open only for reading) and regular file
 2495                  * vnodes open for writing.
 2496                  */
 2497                 if (flags & WRITECLOSE) {
 2498                         error = VOP_GETATTR(vp, &vattr, td->td_ucred);
 2499                         VI_LOCK(vp);
 2500 
 2501                         if ((vp->v_type == VNON ||
 2502                             (error == 0 && vattr.va_nlink > 0)) &&
 2503                             (vp->v_writecount == 0 || vp->v_type != VREG)) {
 2504                                 VOP_UNLOCK(vp, 0);
 2505                                 vdropl(vp);
 2506                                 MNT_ILOCK(mp);
 2507                                 continue;
 2508                         }
 2509                 } else
 2510                         VI_LOCK(vp);
 2511                 /*
 2512                  * With v_usecount == 0, all we need to do is clear out the
 2513                  * vnode data structures and we are done.
 2514                  *
 2515                  * If FORCECLOSE is set, forcibly close the vnode.
 2516                  */
 2517                 if (vp->v_usecount == 0 || (flags & FORCECLOSE)) {
 2518                         VNASSERT(vp->v_usecount == 0 ||
 2519                             (vp->v_type != VCHR && vp->v_type != VBLK), vp,
 2520                             ("device VNODE %p is FORCECLOSED", vp));
 2521                         vgonel(vp);
 2522                 } else {
 2523                         busy++;
 2524 #ifdef DIAGNOSTIC
 2525                         if (busyprt)
 2526                                 vprint("vflush: busy vnode", vp);
 2527 #endif
 2528                 }
 2529                 VOP_UNLOCK(vp, 0);
 2530                 vdropl(vp);
 2531                 MNT_ILOCK(mp);
 2532         }
 2533         MNT_IUNLOCK(mp);
 2534         if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
 2535                 /*
 2536                  * If just the root vnode is busy, and if its refcount
 2537                  * is equal to `rootrefs', then go ahead and kill it.
 2538                  */
 2539                 VI_LOCK(rootvp);
 2540                 KASSERT(busy > 0, ("vflush: not busy"));
 2541                 VNASSERT(rootvp->v_usecount >= rootrefs, rootvp,
 2542                     ("vflush: usecount %d < rootrefs %d",
 2543                      rootvp->v_usecount, rootrefs));
 2544                 if (busy == 1 && rootvp->v_usecount == rootrefs) {
 2545                         VOP_LOCK(rootvp, LK_EXCLUSIVE|LK_INTERLOCK);
 2546                         vgone(rootvp);
 2547                         VOP_UNLOCK(rootvp, 0);
 2548                         busy = 0;
 2549                 } else
 2550                         VI_UNLOCK(rootvp);
 2551         }
 2552         if (busy) {
 2553                 CTR2(KTR_VFS, "%s: failing as %d vnodes are busy", __func__,
 2554                     busy);
 2555                 return (EBUSY);
 2556         }
 2557         for (; rootrefs > 0; rootrefs--)
 2558                 vrele(rootvp);
 2559         return (0);
 2560 }
 2561 
 2562 /*
 2563  * Recycle an unused vnode to the front of the free list.
 2564  */
 2565 int
 2566 vrecycle(struct vnode *vp, struct thread *td)
 2567 {
 2568         int recycled;
 2569 
 2570         ASSERT_VOP_ELOCKED(vp, "vrecycle");
 2571         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2572         recycled = 0;
 2573         VI_LOCK(vp);
 2574         if (vp->v_usecount == 0) {
 2575                 recycled = 1;
 2576                 vgonel(vp);
 2577         }
 2578         VI_UNLOCK(vp);
 2579         return (recycled);
 2580 }
 2581 
 2582 /*
 2583  * Eliminate all activity associated with a vnode
 2584  * in preparation for reuse.
 2585  */
 2586 void
 2587 vgone(struct vnode *vp)
 2588 {
 2589         VI_LOCK(vp);
 2590         vgonel(vp);
 2591         VI_UNLOCK(vp);
 2592 }
 2593 
 2594 /*
 2595  * vgone, with the vp interlock held.
 2596  */
 2597 void
 2598 vgonel(struct vnode *vp)
 2599 {
 2600         struct thread *td;
 2601         int oweinact;
 2602         int active;
 2603         struct mount *mp;
 2604 
 2605         ASSERT_VOP_ELOCKED(vp, "vgonel");
 2606         ASSERT_VI_LOCKED(vp, "vgonel");
 2607         VNASSERT(vp->v_holdcnt, vp,
 2608             ("vgonel: vp %p has no reference.", vp));
 2609         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2610         td = curthread;
 2611 
 2612         /*
 2613          * Don't vgonel if we're already doomed.
 2614          */
 2615         if (vp->v_iflag & VI_DOOMED)
 2616                 return;
 2617         vp->v_iflag |= VI_DOOMED;
 2618         /*
 2619          * Check to see if the vnode is in use.  If so, we have to call
 2620          * VOP_CLOSE() and VOP_INACTIVE().
 2621          */
 2622         active = vp->v_usecount;
 2623         oweinact = (vp->v_iflag & VI_OWEINACT);
 2624         VI_UNLOCK(vp);
 2625         /*
 2626          * Clean out any buffers associated with the vnode.
 2627          * If the flush fails, just toss the buffers.
 2628          */
 2629         mp = NULL;
 2630         if (!TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd))
 2631                 (void) vn_start_secondary_write(vp, &mp, V_WAIT);
 2632         if (vinvalbuf(vp, V_SAVE, 0, 0) != 0)
 2633                 vinvalbuf(vp, 0, 0, 0);
 2634 
 2635         /*
 2636          * If purging an active vnode, it must be closed and
 2637          * deactivated before being reclaimed.
 2638          */
 2639         if (active)
 2640                 VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
 2641         if (oweinact || active) {
 2642                 VI_LOCK(vp);
 2643                 if ((vp->v_iflag & VI_DOINGINACT) == 0)
 2644                         vinactive(vp, td);
 2645                 VI_UNLOCK(vp);
 2646         }
 2647         /*
 2648          * Reclaim the vnode.
 2649          */
 2650         if (VOP_RECLAIM(vp, td))
 2651                 panic("vgone: cannot reclaim");
 2652         if (mp != NULL)
 2653                 vn_finished_secondary_write(mp);
 2654         VNASSERT(vp->v_object == NULL, vp,
 2655             ("vop_reclaim left v_object vp=%p, tag=%s", vp, vp->v_tag));
 2656         /*
 2657          * Clear the advisory locks and wake up waiting threads.
 2658          */
 2659         (void)VOP_ADVLOCKPURGE(vp);
 2660         /*
 2661          * Delete from old mount point vnode list.
 2662          */
 2663         delmntque(vp);
 2664         cache_purge(vp);
 2665         /*
 2666          * Done with purge, reset to the standard lock and invalidate
 2667          * the vnode.
 2668          */
 2669         VI_LOCK(vp);
 2670         vp->v_vnlock = &vp->v_lock;
 2671         vp->v_op = &dead_vnodeops;
 2672         vp->v_tag = "none";
 2673         vp->v_type = VBAD;
 2674 }
 2675 
 2676 /*
 2677  * Calculate the total number of references to a special device.
 2678  */
 2679 int
 2680 vcount(struct vnode *vp)
 2681 {
 2682         int count;
 2683 
 2684         dev_lock();
 2685         count = vp->v_rdev->si_usecount;
 2686         dev_unlock();
 2687         return (count);
 2688 }
 2689 
 2690 /*
 2691  * Same as above, but using the struct cdev *as argument
 2692  */
 2693 int
 2694 count_dev(struct cdev *dev)
 2695 {
 2696         int count;
 2697 
 2698         dev_lock();
 2699         count = dev->si_usecount;
 2700         dev_unlock();
 2701         return(count);
 2702 }
 2703 
 2704 /*
 2705  * Print out a description of a vnode.
 2706  */
 2707 static char *typename[] =
 2708 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD",
 2709  "VMARKER"};
 2710 
 2711 void
 2712 vn_printf(struct vnode *vp, const char *fmt, ...)
 2713 {
 2714         va_list ap;
 2715         char buf[256], buf2[16];
 2716         u_long flags;
 2717 
 2718         va_start(ap, fmt);
 2719         vprintf(fmt, ap);
 2720         va_end(ap);
 2721         printf("%p: ", (void *)vp);
 2722         printf("tag %s, type %s\n", vp->v_tag, typename[vp->v_type]);
 2723         printf("    usecount %d, writecount %d, refcount %d mountedhere %p\n",
 2724             vp->v_usecount, vp->v_writecount, vp->v_holdcnt, vp->v_mountedhere);
 2725         buf[0] = '\0';
 2726         buf[1] = '\0';
 2727         if (vp->v_vflag & VV_ROOT)
 2728                 strlcat(buf, "|VV_ROOT", sizeof(buf));
 2729         if (vp->v_vflag & VV_ISTTY)
 2730                 strlcat(buf, "|VV_ISTTY", sizeof(buf));
 2731         if (vp->v_vflag & VV_NOSYNC)
 2732                 strlcat(buf, "|VV_NOSYNC", sizeof(buf));
 2733         if (vp->v_vflag & VV_CACHEDLABEL)
 2734                 strlcat(buf, "|VV_CACHEDLABEL", sizeof(buf));
 2735         if (vp->v_vflag & VV_TEXT)
 2736                 strlcat(buf, "|VV_TEXT", sizeof(buf));
 2737         if (vp->v_vflag & VV_COPYONWRITE)
 2738                 strlcat(buf, "|VV_COPYONWRITE", sizeof(buf));
 2739         if (vp->v_vflag & VV_SYSTEM)
 2740                 strlcat(buf, "|VV_SYSTEM", sizeof(buf));
 2741         if (vp->v_vflag & VV_PROCDEP)
 2742                 strlcat(buf, "|VV_PROCDEP", sizeof(buf));
 2743         if (vp->v_vflag & VV_NOKNOTE)
 2744                 strlcat(buf, "|VV_NOKNOTE", sizeof(buf));
 2745         if (vp->v_vflag & VV_DELETED)
 2746                 strlcat(buf, "|VV_DELETED", sizeof(buf));
 2747         if (vp->v_vflag & VV_MD)
 2748                 strlcat(buf, "|VV_MD", sizeof(buf));
 2749         flags = vp->v_vflag & ~(VV_ROOT | VV_ISTTY | VV_NOSYNC |
 2750             VV_CACHEDLABEL | VV_TEXT | VV_COPYONWRITE | VV_SYSTEM | VV_PROCDEP |
 2751             VV_NOKNOTE | VV_DELETED | VV_MD);
 2752         if (flags != 0) {
 2753                 snprintf(buf2, sizeof(buf2), "|VV(0x%lx)", flags);
 2754                 strlcat(buf, buf2, sizeof(buf));
 2755         }
 2756         if (vp->v_iflag & VI_MOUNT)
 2757                 strlcat(buf, "|VI_MOUNT", sizeof(buf));
 2758         if (vp->v_iflag & VI_AGE)
 2759                 strlcat(buf, "|VI_AGE", sizeof(buf));
 2760         if (vp->v_iflag & VI_DOOMED)
 2761                 strlcat(buf, "|VI_DOOMED", sizeof(buf));
 2762         if (vp->v_iflag & VI_FREE)
 2763                 strlcat(buf, "|VI_FREE", sizeof(buf));
 2764         if (vp->v_iflag & VI_DOINGINACT)
 2765                 strlcat(buf, "|VI_DOINGINACT", sizeof(buf));
 2766         if (vp->v_iflag & VI_OWEINACT)
 2767                 strlcat(buf, "|VI_OWEINACT", sizeof(buf));
 2768         flags = vp->v_iflag & ~(VI_MOUNT | VI_AGE | VI_DOOMED | VI_FREE |
 2769             VI_DOINGINACT | VI_OWEINACT);
 2770         if (flags != 0) {
 2771                 snprintf(buf2, sizeof(buf2), "|VI(0x%lx)", flags);
 2772                 strlcat(buf, buf2, sizeof(buf));
 2773         }
 2774         printf("    flags (%s)\n", buf + 1);
 2775         if (mtx_owned(VI_MTX(vp)))
 2776                 printf(" VI_LOCKed");
 2777         if (vp->v_object != NULL)
 2778                 printf("    v_object %p ref %d pages %d\n",
 2779                     vp->v_object, vp->v_object->ref_count,
 2780                     vp->v_object->resident_page_count);
 2781         printf("    ");
 2782         lockmgr_printinfo(vp->v_vnlock);
 2783         if (vp->v_data != NULL)
 2784                 VOP_PRINT(vp);
 2785 }
 2786 
 2787 #ifdef DDB
 2788 /*
 2789  * List all of the locked vnodes in the system.
 2790  * Called when debugging the kernel.
 2791  */
 2792 DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
 2793 {
 2794         struct mount *mp, *nmp;
 2795         struct vnode *vp;
 2796 
 2797         /*
 2798          * Note: because this is DDB, we can't obey the locking semantics
 2799          * for these structures, which means we could catch an inconsistent
 2800          * state and dereference a nasty pointer.  Not much to be done
 2801          * about that.
 2802          */
 2803         db_printf("Locked vnodes\n");
 2804         for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
 2805                 nmp = TAILQ_NEXT(mp, mnt_list);
 2806                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2807                         if (vp->v_type != VMARKER &&
 2808                             VOP_ISLOCKED(vp))
 2809                                 vprint("", vp);
 2810                 }
 2811                 nmp = TAILQ_NEXT(mp, mnt_list);
 2812         }
 2813 }
 2814 
 2815 /*
 2816  * Show details about the given vnode.
 2817  */
 2818 DB_SHOW_COMMAND(vnode, db_show_vnode)
 2819 {
 2820         struct vnode *vp;
 2821 
 2822         if (!have_addr)
 2823                 return;
 2824         vp = (struct vnode *)addr;
 2825         vn_printf(vp, "vnode ");
 2826 }
 2827 
 2828 /*
 2829  * Show details about the given mount point.
 2830  */
 2831 DB_SHOW_COMMAND(mount, db_show_mount)
 2832 {
 2833         struct mount *mp;
 2834         struct vfsopt *opt;
 2835         struct statfs *sp;
 2836         struct vnode *vp;
 2837         char buf[512];
 2838         u_int flags;
 2839 
 2840         if (!have_addr) {
 2841                 /* No address given, print short info about all mount points. */
 2842                 TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 2843                         db_printf("%p %s on %s (%s)\n", mp,
 2844                             mp->mnt_stat.f_mntfromname,
 2845                             mp->mnt_stat.f_mntonname,
 2846                             mp->mnt_stat.f_fstypename);
 2847                         if (db_pager_quit)
 2848                                 break;
 2849                 }
 2850                 db_printf("\nMore info: show mount <addr>\n");
 2851                 return;
 2852         }
 2853 
 2854         mp = (struct mount *)addr;
 2855         db_printf("%p %s on %s (%s)\n", mp, mp->mnt_stat.f_mntfromname,
 2856             mp->mnt_stat.f_mntonname, mp->mnt_stat.f_fstypename);
 2857 
 2858         buf[0] = '\0';
 2859         flags = mp->mnt_flag;
 2860 #define MNT_FLAG(flag)  do {                                            \
 2861         if (flags & (flag)) {                                           \
 2862                 if (buf[0] != '\0')                                     \
 2863                         strlcat(buf, ", ", sizeof(buf));                \
 2864                 strlcat(buf, (#flag) + 4, sizeof(buf));                 \
 2865                 flags &= ~(flag);                                       \
 2866         }                                                               \
 2867 } while (0)
 2868         MNT_FLAG(MNT_RDONLY);
 2869         MNT_FLAG(MNT_SYNCHRONOUS);
 2870         MNT_FLAG(MNT_NOEXEC);
 2871         MNT_FLAG(MNT_NOSUID);
 2872         MNT_FLAG(MNT_UNION);
 2873         MNT_FLAG(MNT_ASYNC);
 2874         MNT_FLAG(MNT_SUIDDIR);
 2875         MNT_FLAG(MNT_SOFTDEP);
 2876         MNT_FLAG(MNT_SUJ);
 2877         MNT_FLAG(MNT_NOSYMFOLLOW);
 2878         MNT_FLAG(MNT_GJOURNAL);
 2879         MNT_FLAG(MNT_MULTILABEL);
 2880         MNT_FLAG(MNT_ACLS);
 2881         MNT_FLAG(MNT_NOATIME);
 2882         MNT_FLAG(MNT_NOCLUSTERR);
 2883         MNT_FLAG(MNT_NOCLUSTERW);
 2884         MNT_FLAG(MNT_NFS4ACLS);
 2885         MNT_FLAG(MNT_EXRDONLY);
 2886         MNT_FLAG(MNT_EXPORTED);
 2887         MNT_FLAG(MNT_DEFEXPORTED);
 2888         MNT_FLAG(MNT_EXPORTANON);
 2889         MNT_FLAG(MNT_EXKERB);
 2890         MNT_FLAG(MNT_EXPUBLIC);
 2891         MNT_FLAG(MNT_LOCAL);
 2892         MNT_FLAG(MNT_QUOTA);
 2893         MNT_FLAG(MNT_ROOTFS);
 2894         MNT_FLAG(MNT_USER);
 2895         MNT_FLAG(MNT_IGNORE);
 2896         MNT_FLAG(MNT_UPDATE);
 2897         MNT_FLAG(MNT_DELEXPORT);
 2898         MNT_FLAG(MNT_RELOAD);
 2899         MNT_FLAG(MNT_FORCE);
 2900         MNT_FLAG(MNT_SNAPSHOT);
 2901         MNT_FLAG(MNT_BYFSID);
 2902 #undef MNT_FLAG
 2903         if (flags != 0) {
 2904                 if (buf[0] != '\0')
 2905                         strlcat(buf, ", ", sizeof(buf));
 2906                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 2907                     "0x%08x", flags);
 2908         }
 2909         db_printf("    mnt_flag = %s\n", buf);
 2910 
 2911         buf[0] = '\0';
 2912         flags = mp->mnt_kern_flag;
 2913 #define MNT_KERN_FLAG(flag)     do {                                    \
 2914         if (flags & (flag)) {                                           \
 2915                 if (buf[0] != '\0')                                     \
 2916                         strlcat(buf, ", ", sizeof(buf));                \
 2917                 strlcat(buf, (#flag) + 5, sizeof(buf));                 \
 2918                 flags &= ~(flag);                                       \
 2919         }                                                               \
 2920 } while (0)
 2921         MNT_KERN_FLAG(MNTK_UNMOUNTF);
 2922         MNT_KERN_FLAG(MNTK_ASYNC);
 2923         MNT_KERN_FLAG(MNTK_SOFTDEP);
 2924         MNT_KERN_FLAG(MNTK_NOINSMNTQ);
 2925         MNT_KERN_FLAG(MNTK_DRAINING);
 2926         MNT_KERN_FLAG(MNTK_REFEXPIRE);
 2927         MNT_KERN_FLAG(MNTK_EXTENDED_SHARED);
 2928         MNT_KERN_FLAG(MNTK_SHARED_WRITES);
 2929         MNT_KERN_FLAG(MNTK_UNMOUNT);
 2930         MNT_KERN_FLAG(MNTK_MWAIT);
 2931         MNT_KERN_FLAG(MNTK_SUSPEND);
 2932         MNT_KERN_FLAG(MNTK_SUSPEND2);
 2933         MNT_KERN_FLAG(MNTK_SUSPENDED);
 2934         MNT_KERN_FLAG(MNTK_MPSAFE);
 2935         MNT_KERN_FLAG(MNTK_LOOKUP_SHARED);
 2936         MNT_KERN_FLAG(MNTK_NOKNOTE);
 2937 #undef MNT_KERN_FLAG
 2938         if (flags != 0) {
 2939                 if (buf[0] != '\0')
 2940                         strlcat(buf, ", ", sizeof(buf));
 2941                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 2942                     "0x%08x", flags);
 2943         }
 2944         db_printf("    mnt_kern_flag = %s\n", buf);
 2945 
 2946         db_printf("    mnt_opt = ");
 2947         opt = TAILQ_FIRST(mp->mnt_opt);
 2948         if (opt != NULL) {
 2949                 db_printf("%s", opt->name);
 2950                 opt = TAILQ_NEXT(opt, link);
 2951                 while (opt != NULL) {
 2952                         db_printf(", %s", opt->name);
 2953                         opt = TAILQ_NEXT(opt, link);
 2954                 }
 2955         }
 2956         db_printf("\n");
 2957 
 2958         sp = &mp->mnt_stat;
 2959         db_printf("    mnt_stat = { version=%u type=%u flags=0x%016jx "
 2960             "bsize=%ju iosize=%ju blocks=%ju bfree=%ju bavail=%jd files=%ju "
 2961             "ffree=%jd syncwrites=%ju asyncwrites=%ju syncreads=%ju "
 2962             "asyncreads=%ju namemax=%u owner=%u fsid=[%d, %d] }\n",
 2963             (u_int)sp->f_version, (u_int)sp->f_type, (uintmax_t)sp->f_flags,
 2964             (uintmax_t)sp->f_bsize, (uintmax_t)sp->f_iosize,
 2965             (uintmax_t)sp->f_blocks, (uintmax_t)sp->f_bfree,
 2966             (intmax_t)sp->f_bavail, (uintmax_t)sp->f_files,
 2967             (intmax_t)sp->f_ffree, (uintmax_t)sp->f_syncwrites,
 2968             (uintmax_t)sp->f_asyncwrites, (uintmax_t)sp->f_syncreads,
 2969             (uintmax_t)sp->f_asyncreads, (u_int)sp->f_namemax,
 2970             (u_int)sp->f_owner, (int)sp->f_fsid.val[0], (int)sp->f_fsid.val[1]);
 2971 
 2972         db_printf("    mnt_cred = { uid=%u ruid=%u",
 2973             (u_int)mp->mnt_cred->cr_uid, (u_int)mp->mnt_cred->cr_ruid);
 2974         if (jailed(mp->mnt_cred))
 2975                 db_printf(", jail=%d", mp->mnt_cred->cr_prison->pr_id);
 2976         db_printf(" }\n");
 2977         db_printf("    mnt_ref = %d\n", mp->mnt_ref);
 2978         db_printf("    mnt_gen = %d\n", mp->mnt_gen);
 2979         db_printf("    mnt_nvnodelistsize = %d\n", mp->mnt_nvnodelistsize);
 2980         db_printf("    mnt_writeopcount = %d\n", mp->mnt_writeopcount);
 2981         db_printf("    mnt_noasync = %u\n", mp->mnt_noasync);
 2982         db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
 2983         db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
 2984         db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
 2985         db_printf("    mnt_secondary_writes = %d\n", mp->mnt_secondary_writes);
 2986         db_printf("    mnt_secondary_accwrites = %d\n",
 2987             mp->mnt_secondary_accwrites);
 2988         db_printf("    mnt_gjprovider = %s\n",
 2989             mp->mnt_gjprovider != NULL ? mp->mnt_gjprovider : "NULL");
 2990         db_printf("\n");
 2991 
 2992         TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2993                 if (vp->v_type != VMARKER) {
 2994                         vn_printf(vp, "vnode ");
 2995                         if (db_pager_quit)
 2996                                 break;
 2997                 }
 2998         }
 2999 }
 3000 #endif  /* DDB */
 3001 
 3002 /*
 3003  * Fill in a struct xvfsconf based on a struct vfsconf.
 3004  */
 3005 static void
 3006 vfsconf2x(struct vfsconf *vfsp, struct xvfsconf *xvfsp)
 3007 {
 3008 
 3009         strcpy(xvfsp->vfc_name, vfsp->vfc_name);
 3010         xvfsp->vfc_typenum = vfsp->vfc_typenum;
 3011         xvfsp->vfc_refcount = vfsp->vfc_refcount;
 3012         xvfsp->vfc_flags = vfsp->vfc_flags;
 3013         /*
 3014          * These are unused in userland, we keep them
 3015          * to not break binary compatibility.
 3016          */
 3017         xvfsp->vfc_vfsops = NULL;
 3018         xvfsp->vfc_next = NULL;
 3019 }
 3020 
 3021 /*
 3022  * Top level filesystem related information gathering.
 3023  */
 3024 static int
 3025 sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
 3026 {
 3027         struct vfsconf *vfsp;
 3028         struct xvfsconf xvfsp;
 3029         int error;
 3030 
 3031         error = 0;
 3032         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3033                 bzero(&xvfsp, sizeof(xvfsp));
 3034                 vfsconf2x(vfsp, &xvfsp);
 3035                 error = SYSCTL_OUT(req, &xvfsp, sizeof xvfsp);
 3036                 if (error)
 3037                         break;
 3038         }
 3039         return (error);
 3040 }
 3041 
 3042 SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLTYPE_OPAQUE | CTLFLAG_RD,
 3043     NULL, 0, sysctl_vfs_conflist,
 3044     "S,xvfsconf", "List of all configured filesystems");
 3045 
 3046 #ifndef BURN_BRIDGES
 3047 static int      sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
 3048 
 3049 static int
 3050 vfs_sysctl(SYSCTL_HANDLER_ARGS)
 3051 {
 3052         int *name = (int *)arg1 - 1;    /* XXX */
 3053         u_int namelen = arg2 + 1;       /* XXX */
 3054         struct vfsconf *vfsp;
 3055         struct xvfsconf xvfsp;
 3056 
 3057         printf("WARNING: userland calling deprecated sysctl, "
 3058             "please rebuild world\n");
 3059 
 3060 #if 1 || defined(COMPAT_PRELITE2)
 3061         /* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
 3062         if (namelen == 1)
 3063                 return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
 3064 #endif
 3065 
 3066         switch (name[1]) {
 3067         case VFS_MAXTYPENUM:
 3068                 if (namelen != 2)
 3069                         return (ENOTDIR);
 3070                 return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
 3071         case VFS_CONF:
 3072                 if (namelen != 3)
 3073                         return (ENOTDIR);       /* overloaded */
 3074                 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
 3075                         if (vfsp->vfc_typenum == name[2])
 3076                                 break;
 3077                 if (vfsp == NULL)
 3078                         return (EOPNOTSUPP);
 3079                 bzero(&xvfsp, sizeof(xvfsp));
 3080                 vfsconf2x(vfsp, &xvfsp);
 3081                 return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 3082         }
 3083         return (EOPNOTSUPP);
 3084 }
 3085 
 3086 static SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP,
 3087     vfs_sysctl, "Generic filesystem");
 3088 
 3089 #if 1 || defined(COMPAT_PRELITE2)
 3090 
 3091 static int
 3092 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
 3093 {
 3094         int error;
 3095         struct vfsconf *vfsp;
 3096         struct ovfsconf ovfs;
 3097 
 3098         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3099                 bzero(&ovfs, sizeof(ovfs));
 3100                 ovfs.vfc_vfsops = vfsp->vfc_vfsops;     /* XXX used as flag */
 3101                 strcpy(ovfs.vfc_name, vfsp->vfc_name);
 3102                 ovfs.vfc_index = vfsp->vfc_typenum;
 3103                 ovfs.vfc_refcount = vfsp->vfc_refcount;
 3104                 ovfs.vfc_flags = vfsp->vfc_flags;
 3105                 error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
 3106                 if (error)
 3107                         return error;
 3108         }
 3109         return 0;
 3110 }
 3111 
 3112 #endif /* 1 || COMPAT_PRELITE2 */
 3113 #endif /* !BURN_BRIDGES */
 3114 
 3115 #define KINFO_VNODESLOP         10
 3116 #ifdef notyet
 3117 /*
 3118  * Dump vnode list (via sysctl).
 3119  */
 3120 /* ARGSUSED */
 3121 static int
 3122 sysctl_vnode(SYSCTL_HANDLER_ARGS)
 3123 {
 3124         struct xvnode *xvn;
 3125         struct mount *mp;
 3126         struct vnode *vp;
 3127         int error, len, n;
 3128 
 3129         /*
 3130          * Stale numvnodes access is not fatal here.
 3131          */
 3132         req->lock = 0;
 3133         len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
 3134         if (!req->oldptr)
 3135                 /* Make an estimate */
 3136                 return (SYSCTL_OUT(req, 0, len));
 3137 
 3138         error = sysctl_wire_old_buffer(req, 0);
 3139         if (error != 0)
 3140                 return (error);
 3141         xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
 3142         n = 0;
 3143         mtx_lock(&mountlist_mtx);
 3144         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 3145                 if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
 3146                         continue;
 3147                 MNT_ILOCK(mp);
 3148                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3149                         if (n == len)
 3150                                 break;
 3151                         vref(vp);
 3152                         xvn[n].xv_size = sizeof *xvn;
 3153                         xvn[n].xv_vnode = vp;
 3154                         xvn[n].xv_id = 0;       /* XXX compat */
 3155 #define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
 3156                         XV_COPY(usecount);
 3157                         XV_COPY(writecount);
 3158                         XV_COPY(holdcnt);
 3159                         XV_COPY(mount);
 3160                         XV_COPY(numoutput);
 3161                         XV_COPY(type);
 3162 #undef XV_COPY
 3163                         xvn[n].xv_flag = vp->v_vflag;
 3164 
 3165                         switch (vp->v_type) {
 3166                         case VREG:
 3167                         case VDIR:
 3168                         case VLNK:
 3169                                 break;
 3170                         case VBLK:
 3171                         case VCHR:
 3172                                 if (vp->v_rdev == NULL) {
 3173                                         vrele(vp);
 3174                                         continue;
 3175                                 }
 3176                                 xvn[n].xv_dev = dev2udev(vp->v_rdev);
 3177                                 break;
 3178                         case VSOCK:
 3179                                 xvn[n].xv_socket = vp->v_socket;
 3180                                 break;
 3181                         case VFIFO:
 3182                                 xvn[n].xv_fifo = vp->v_fifoinfo;
 3183                                 break;
 3184                         case VNON:
 3185                         case VBAD:
 3186                         default:
 3187                                 /* shouldn't happen? */
 3188                                 vrele(vp);
 3189                                 continue;
 3190                         }
 3191                         vrele(vp);
 3192                         ++n;
 3193                 }
 3194                 MNT_IUNLOCK(mp);
 3195                 mtx_lock(&mountlist_mtx);
 3196                 vfs_unbusy(mp);
 3197                 if (n == len)
 3198                         break;
 3199         }
 3200         mtx_unlock(&mountlist_mtx);
 3201 
 3202         error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
 3203         free(xvn, M_TEMP);
 3204         return (error);
 3205 }
 3206 
 3207 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
 3208     0, 0, sysctl_vnode, "S,xvnode", "");
 3209 #endif
 3210 
 3211 /*
 3212  * Unmount all filesystems. The list is traversed in reverse order
 3213  * of mounting to avoid dependencies.
 3214  */
 3215 void
 3216 vfs_unmountall(void)
 3217 {
 3218         struct mount *mp;
 3219         struct thread *td;
 3220         int error;
 3221 
 3222         KASSERT(curthread != NULL, ("vfs_unmountall: NULL curthread"));
 3223         CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__);
 3224         td = curthread;
 3225 
 3226         /*
 3227          * Since this only runs when rebooting, it is not interlocked.
 3228          */
 3229         while(!TAILQ_EMPTY(&mountlist)) {
 3230                 mp = TAILQ_LAST(&mountlist, mntlist);
 3231                 error = dounmount(mp, MNT_FORCE, td);
 3232                 if (error) {
 3233                         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 3234                         /*
 3235                          * XXX: Due to the way in which we mount the root
 3236                          * file system off of devfs, devfs will generate a
 3237                          * "busy" warning when we try to unmount it before
 3238                          * the root.  Don't print a warning as a result in
 3239                          * order to avoid false positive errors that may
 3240                          * cause needless upset.
 3241                          */
 3242                         if (strcmp(mp->mnt_vfc->vfc_name, "devfs") != 0) {
 3243                                 printf("unmount of %s failed (",
 3244                                     mp->mnt_stat.f_mntonname);
 3245                                 if (error == EBUSY)
 3246                                         printf("BUSY)\n");
 3247                                 else
 3248                                         printf("%d)\n", error);
 3249                         }
 3250                 } else {
 3251                         /* The unmount has removed mp from the mountlist */
 3252                 }
 3253         }
 3254 }
 3255 
 3256 /*
 3257  * perform msync on all vnodes under a mount point
 3258  * the mount point must be locked.
 3259  */
 3260 void
 3261 vfs_msync(struct mount *mp, int flags)
 3262 {
 3263         struct vnode *vp, *mvp;
 3264         struct vm_object *obj;
 3265 
 3266         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
 3267         MNT_ILOCK(mp);
 3268         MNT_VNODE_FOREACH(vp, mp, mvp) {
 3269                 VI_LOCK(vp);
 3270                 obj = vp->v_object;
 3271                 if (obj != NULL && (obj->flags & OBJ_MIGHTBEDIRTY) != 0 &&
 3272                     (flags == MNT_WAIT || VOP_ISLOCKED(vp) == 0)) {
 3273                         MNT_IUNLOCK(mp);
 3274                         if (!vget(vp,
 3275                             LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
 3276                             curthread)) {
 3277                                 if (vp->v_vflag & VV_NOSYNC) {  /* unlinked */
 3278                                         vput(vp);
 3279                                         MNT_ILOCK(mp);
 3280                                         continue;
 3281                                 }
 3282 
 3283                                 obj = vp->v_object;
 3284                                 if (obj != NULL) {
 3285                                         VM_OBJECT_LOCK(obj);
 3286                                         vm_object_page_clean(obj, 0, 0,
 3287                                             flags == MNT_WAIT ?
 3288                                             OBJPC_SYNC : OBJPC_NOSYNC);
 3289                                         VM_OBJECT_UNLOCK(obj);
 3290                                 }
 3291                                 vput(vp);
 3292                         }
 3293                         MNT_ILOCK(mp);
 3294                 } else
 3295                         VI_UNLOCK(vp);
 3296         }
 3297         MNT_IUNLOCK(mp);
 3298 }
 3299 
 3300 /*
 3301  * Mark a vnode as free, putting it up for recycling.
 3302  */
 3303 static void
 3304 vfree(struct vnode *vp)
 3305 {
 3306 
 3307         ASSERT_VI_LOCKED(vp, "vfree");
 3308         mtx_lock(&vnode_free_list_mtx);
 3309         VNASSERT(vp->v_op != NULL, vp, ("vfree: vnode already reclaimed."));
 3310         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp, ("vnode already free"));
 3311         VNASSERT(VSHOULDFREE(vp), vp, ("vfree: freeing when we shouldn't"));
 3312         VNASSERT((vp->v_iflag & VI_DOOMED) == 0, vp,
 3313             ("vfree: Freeing doomed vnode"));
 3314         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3315         if (vp->v_iflag & VI_AGE) {
 3316                 TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
 3317         } else {
 3318                 TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 3319         }
 3320         freevnodes++;
 3321         vp->v_iflag &= ~VI_AGE;
 3322         vp->v_iflag |= VI_FREE;
 3323         mtx_unlock(&vnode_free_list_mtx);
 3324 }
 3325 
 3326 /*
 3327  * Opposite of vfree() - mark a vnode as in use.
 3328  */
 3329 static void
 3330 vbusy(struct vnode *vp)
 3331 {
 3332         ASSERT_VI_LOCKED(vp, "vbusy");
 3333         VNASSERT((vp->v_iflag & VI_FREE) != 0, vp, ("vnode not free"));
 3334         VNASSERT(vp->v_op != NULL, vp, ("vbusy: vnode already reclaimed."));
 3335         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3336 
 3337         mtx_lock(&vnode_free_list_mtx);
 3338         TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
 3339         freevnodes--;
 3340         vp->v_iflag &= ~(VI_FREE|VI_AGE);
 3341         mtx_unlock(&vnode_free_list_mtx);
 3342 }
 3343 
 3344 static void
 3345 destroy_vpollinfo(struct vpollinfo *vi)
 3346 {
 3347         seldrain(&vi->vpi_selinfo);
 3348         knlist_destroy(&vi->vpi_selinfo.si_note);
 3349         mtx_destroy(&vi->vpi_lock);
 3350         uma_zfree(vnodepoll_zone, vi);
 3351 }
 3352 
 3353 /*
 3354  * Initalize per-vnode helper structure to hold poll-related state.
 3355  */
 3356 void
 3357 v_addpollinfo(struct vnode *vp)
 3358 {
 3359         struct vpollinfo *vi;
 3360 
 3361         if (vp->v_pollinfo != NULL)
 3362                 return;
 3363         vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
 3364         mtx_init(&vi->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
 3365         knlist_init(&vi->vpi_selinfo.si_note, vp, vfs_knllock,
 3366             vfs_knlunlock, vfs_knl_assert_locked, vfs_knl_assert_unlocked);
 3367         VI_LOCK(vp);
 3368         if (vp->v_pollinfo != NULL) {
 3369                 VI_UNLOCK(vp);
 3370                 destroy_vpollinfo(vi);
 3371                 return;
 3372         }
 3373         vp->v_pollinfo = vi;
 3374         VI_UNLOCK(vp);
 3375 }
 3376 
 3377 /*
 3378  * Record a process's interest in events which might happen to
 3379  * a vnode.  Because poll uses the historic select-style interface
 3380  * internally, this routine serves as both the ``check for any
 3381  * pending events'' and the ``record my interest in future events''
 3382  * functions.  (These are done together, while the lock is held,
 3383  * to avoid race conditions.)
 3384  */
 3385 int
 3386 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
 3387 {
 3388 
 3389         v_addpollinfo(vp);
 3390         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3391         if (vp->v_pollinfo->vpi_revents & events) {
 3392                 /*
 3393                  * This leaves events we are not interested
 3394                  * in available for the other process which
 3395                  * which presumably had requested them
 3396                  * (otherwise they would never have been
 3397                  * recorded).
 3398                  */
 3399                 events &= vp->v_pollinfo->vpi_revents;
 3400                 vp->v_pollinfo->vpi_revents &= ~events;
 3401 
 3402                 mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3403                 return (events);
 3404         }
 3405         vp->v_pollinfo->vpi_events |= events;
 3406         selrecord(td, &vp->v_pollinfo->vpi_selinfo);
 3407         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3408         return (0);
 3409 }
 3410 
 3411 /*
 3412  * Routine to create and manage a filesystem syncer vnode.
 3413  */
 3414 #define sync_close ((int (*)(struct  vop_close_args *))nullop)
 3415 static int      sync_fsync(struct  vop_fsync_args *);
 3416 static int      sync_inactive(struct  vop_inactive_args *);
 3417 static int      sync_reclaim(struct  vop_reclaim_args *);
 3418 
 3419 static struct vop_vector sync_vnodeops = {
 3420         .vop_bypass =   VOP_EOPNOTSUPP,
 3421         .vop_close =    sync_close,             /* close */
 3422         .vop_fsync =    sync_fsync,             /* fsync */
 3423         .vop_inactive = sync_inactive,  /* inactive */
 3424         .vop_reclaim =  sync_reclaim,   /* reclaim */
 3425         .vop_lock1 =    vop_stdlock,    /* lock */
 3426         .vop_unlock =   vop_stdunlock,  /* unlock */
 3427         .vop_islocked = vop_stdislocked,        /* islocked */
 3428 };
 3429 
 3430 /*
 3431  * Create a new filesystem syncer vnode for the specified mount point.
 3432  */
 3433 void
 3434 vfs_allocate_syncvnode(struct mount *mp)
 3435 {
 3436         struct vnode *vp;
 3437         struct bufobj *bo;
 3438         static long start, incr, next;
 3439         int error;
 3440 
 3441         /* Allocate a new vnode */
 3442         error = getnewvnode("syncer", mp, &sync_vnodeops, &vp);
 3443         if (error != 0)
 3444                 panic("vfs_allocate_syncvnode: getnewvnode() failed");
 3445         vp->v_type = VNON;
 3446         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3447         vp->v_vflag |= VV_FORCEINSMQ;
 3448         error = insmntque(vp, mp);
 3449         if (error != 0)
 3450                 panic("vfs_allocate_syncvnode: insmntque() failed");
 3451         vp->v_vflag &= ~VV_FORCEINSMQ;
 3452         VOP_UNLOCK(vp, 0);
 3453         /*
 3454          * Place the vnode onto the syncer worklist. We attempt to
 3455          * scatter them about on the list so that they will go off
 3456          * at evenly distributed times even if all the filesystems
 3457          * are mounted at once.
 3458          */
 3459         next += incr;
 3460         if (next == 0 || next > syncer_maxdelay) {
 3461                 start /= 2;
 3462                 incr /= 2;
 3463                 if (start == 0) {
 3464                         start = syncer_maxdelay / 2;
 3465                         incr = syncer_maxdelay;
 3466                 }
 3467                 next = start;
 3468         }
 3469         bo = &vp->v_bufobj;
 3470         BO_LOCK(bo);
 3471         vn_syncer_add_to_worklist(bo, syncdelay > 0 ? next % syncdelay : 0);
 3472         /* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
 3473         mtx_lock(&sync_mtx);
 3474         sync_vnode_count++;
 3475         if (mp->mnt_syncer == NULL) {
 3476                 mp->mnt_syncer = vp;
 3477                 vp = NULL;
 3478         }
 3479         mtx_unlock(&sync_mtx);
 3480         BO_UNLOCK(bo);
 3481         if (vp != NULL) {
 3482                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3483                 vgone(vp);
 3484                 vput(vp);
 3485         }
 3486 }
 3487 
 3488 void
 3489 vfs_deallocate_syncvnode(struct mount *mp)
 3490 {
 3491         struct vnode *vp;
 3492 
 3493         mtx_lock(&sync_mtx);
 3494         vp = mp->mnt_syncer;
 3495         if (vp != NULL)
 3496                 mp->mnt_syncer = NULL;
 3497         mtx_unlock(&sync_mtx);
 3498         if (vp != NULL)
 3499                 vrele(vp);
 3500 }
 3501 
 3502 /*
 3503  * Do a lazy sync of the filesystem.
 3504  */
 3505 static int
 3506 sync_fsync(struct vop_fsync_args *ap)
 3507 {
 3508         struct vnode *syncvp = ap->a_vp;
 3509         struct mount *mp = syncvp->v_mount;
 3510         int error;
 3511         struct bufobj *bo;
 3512 
 3513         /*
 3514          * We only need to do something if this is a lazy evaluation.
 3515          */
 3516         if (ap->a_waitfor != MNT_LAZY)
 3517                 return (0);
 3518 
 3519         /*
 3520          * Move ourselves to the back of the sync list.
 3521          */
 3522         bo = &syncvp->v_bufobj;
 3523         BO_LOCK(bo);
 3524         vn_syncer_add_to_worklist(bo, syncdelay);
 3525         BO_UNLOCK(bo);
 3526 
 3527         /*
 3528          * Walk the list of vnodes pushing all that are dirty and
 3529          * not already on the sync list.
 3530          */
 3531         mtx_lock(&mountlist_mtx);
 3532         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK) != 0) {
 3533                 mtx_unlock(&mountlist_mtx);
 3534                 return (0);
 3535         }
 3536         if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
 3537                 vfs_unbusy(mp);
 3538                 return (0);
 3539         }
 3540         MNT_ILOCK(mp);
 3541         mp->mnt_noasync++;
 3542         mp->mnt_kern_flag &= ~MNTK_ASYNC;
 3543         MNT_IUNLOCK(mp);
 3544         vfs_msync(mp, MNT_NOWAIT);
 3545         error = VFS_SYNC(mp, MNT_LAZY);
 3546         MNT_ILOCK(mp);
 3547         mp->mnt_noasync--;
 3548         if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
 3549                 mp->mnt_kern_flag |= MNTK_ASYNC;
 3550         MNT_IUNLOCK(mp);
 3551         vn_finished_write(mp);
 3552         vfs_unbusy(mp);
 3553         return (error);
 3554 }
 3555 
 3556 /*
 3557  * The syncer vnode is no referenced.
 3558  */
 3559 static int
 3560 sync_inactive(struct vop_inactive_args *ap)
 3561 {
 3562 
 3563         vgone(ap->a_vp);
 3564         return (0);
 3565 }
 3566 
 3567 /*
 3568  * The syncer vnode is no longer needed and is being decommissioned.
 3569  *
 3570  * Modifications to the worklist must be protected by sync_mtx.
 3571  */
 3572 static int
 3573 sync_reclaim(struct vop_reclaim_args *ap)
 3574 {
 3575         struct vnode *vp = ap->a_vp;
 3576         struct bufobj *bo;
 3577 
 3578         bo = &vp->v_bufobj;
 3579         BO_LOCK(bo);
 3580         mtx_lock(&sync_mtx);
 3581         if (vp->v_mount->mnt_syncer == vp)
 3582                 vp->v_mount->mnt_syncer = NULL;
 3583         if (bo->bo_flag & BO_ONWORKLST) {
 3584                 LIST_REMOVE(bo, bo_synclist);
 3585                 syncer_worklist_len--;
 3586                 sync_vnode_count--;
 3587                 bo->bo_flag &= ~BO_ONWORKLST;
 3588         }
 3589         mtx_unlock(&sync_mtx);
 3590         BO_UNLOCK(bo);
 3591 
 3592         return (0);
 3593 }
 3594 
 3595 /*
 3596  * Check if vnode represents a disk device
 3597  */
 3598 int
 3599 vn_isdisk(struct vnode *vp, int *errp)
 3600 {
 3601         int error;
 3602 
 3603         error = 0;
 3604         dev_lock();
 3605         if (vp->v_type != VCHR)
 3606                 error = ENOTBLK;
 3607         else if (vp->v_rdev == NULL)
 3608                 error = ENXIO;
 3609         else if (vp->v_rdev->si_devsw == NULL)
 3610                 error = ENXIO;
 3611         else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
 3612                 error = ENOTBLK;
 3613         dev_unlock();
 3614         if (errp != NULL)
 3615                 *errp = error;
 3616         return (error == 0);
 3617 }
 3618 
 3619 /*
 3620  * Common filesystem object access control check routine.  Accepts a
 3621  * vnode's type, "mode", uid and gid, requested access mode, credentials,
 3622  * and optional call-by-reference privused argument allowing vaccess()
 3623  * to indicate to the caller whether privilege was used to satisfy the
 3624  * request (obsoleted).  Returns 0 on success, or an errno on failure.
 3625  */
 3626 int
 3627 vaccess(enum vtype type, mode_t file_mode, uid_t file_uid, gid_t file_gid,
 3628     accmode_t accmode, struct ucred *cred, int *privused)
 3629 {
 3630         accmode_t dac_granted;
 3631         accmode_t priv_granted;
 3632 
 3633         KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND)) == 0,
 3634             ("invalid bit in accmode"));
 3635         KASSERT((accmode & VAPPEND) == 0 || (accmode & VWRITE),
 3636             ("VAPPEND without VWRITE"));
 3637 
 3638         /*
 3639          * Look for a normal, non-privileged way to access the file/directory
 3640          * as requested.  If it exists, go with that.
 3641          */
 3642 
 3643         if (privused != NULL)
 3644                 *privused = 0;
 3645 
 3646         dac_granted = 0;
 3647 
 3648         /* Check the owner. */
 3649         if (cred->cr_uid == file_uid) {
 3650                 dac_granted |= VADMIN;
 3651                 if (file_mode & S_IXUSR)
 3652                         dac_granted |= VEXEC;
 3653                 if (file_mode & S_IRUSR)
 3654                         dac_granted |= VREAD;
 3655                 if (file_mode & S_IWUSR)
 3656                         dac_granted |= (VWRITE | VAPPEND);
 3657 
 3658                 if ((accmode & dac_granted) == accmode)
 3659                         return (0);
 3660 
 3661                 goto privcheck;
 3662         }
 3663 
 3664         /* Otherwise, check the groups (first match) */
 3665         if (groupmember(file_gid, cred)) {
 3666                 if (file_mode & S_IXGRP)
 3667                         dac_granted |= VEXEC;
 3668                 if (file_mode & S_IRGRP)
 3669                         dac_granted |= VREAD;
 3670                 if (file_mode & S_IWGRP)
 3671                         dac_granted |= (VWRITE | VAPPEND);
 3672 
 3673                 if ((accmode & dac_granted) == accmode)
 3674                         return (0);
 3675 
 3676                 goto privcheck;
 3677         }
 3678 
 3679         /* Otherwise, check everyone else. */
 3680         if (file_mode & S_IXOTH)
 3681                 dac_granted |= VEXEC;
 3682         if (file_mode & S_IROTH)
 3683                 dac_granted |= VREAD;
 3684         if (file_mode & S_IWOTH)
 3685                 dac_granted |= (VWRITE | VAPPEND);
 3686         if ((accmode & dac_granted) == accmode)
 3687                 return (0);
 3688 
 3689 privcheck:
 3690         /*
 3691          * Build a privilege mask to determine if the set of privileges
 3692          * satisfies the requirements when combined with the granted mask
 3693          * from above.  For each privilege, if the privilege is required,
 3694          * bitwise or the request type onto the priv_granted mask.
 3695          */
 3696         priv_granted = 0;
 3697 
 3698         if (type == VDIR) {
 3699                 /*
 3700                  * For directories, use PRIV_VFS_LOOKUP to satisfy VEXEC
 3701                  * requests, instead of PRIV_VFS_EXEC.
 3702                  */
 3703                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3704                     !priv_check_cred(cred, PRIV_VFS_LOOKUP, 0))
 3705                         priv_granted |= VEXEC;
 3706         } else {
 3707                 /*
 3708                  * Ensure that at least one execute bit is on. Otherwise,
 3709                  * a privileged user will always succeed, and we don't want
 3710                  * this to happen unless the file really is executable.
 3711                  */
 3712                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3713                     (file_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0 &&
 3714                     !priv_check_cred(cred, PRIV_VFS_EXEC, 0))
 3715                         priv_granted |= VEXEC;
 3716         }
 3717 
 3718         if ((accmode & VREAD) && ((dac_granted & VREAD) == 0) &&
 3719             !priv_check_cred(cred, PRIV_VFS_READ, 0))
 3720                 priv_granted |= VREAD;
 3721 
 3722         if ((accmode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
 3723             !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
 3724                 priv_granted |= (VWRITE | VAPPEND);
 3725 
 3726         if ((accmode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
 3727             !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
 3728                 priv_granted |= VADMIN;
 3729 
 3730         if ((accmode & (priv_granted | dac_granted)) == accmode) {
 3731                 /* XXX audit: privilege used */
 3732                 if (privused != NULL)
 3733                         *privused = 1;
 3734                 return (0);
 3735         }
 3736 
 3737         return ((accmode & VADMIN) ? EPERM : EACCES);
 3738 }
 3739 
 3740 /*
 3741  * Credential check based on process requesting service, and per-attribute
 3742  * permissions.
 3743  */
 3744 int
 3745 extattr_check_cred(struct vnode *vp, int attrnamespace, struct ucred *cred,
 3746     struct thread *td, accmode_t accmode)
 3747 {
 3748 
 3749         /*
 3750          * Kernel-invoked always succeeds.
 3751          */
 3752         if (cred == NOCRED)
 3753                 return (0);
 3754 
 3755         /*
 3756          * Do not allow privileged processes in jail to directly manipulate
 3757          * system attributes.
 3758          */
 3759         switch (attrnamespace) {
 3760         case EXTATTR_NAMESPACE_SYSTEM:
 3761                 /* Potentially should be: return (EPERM); */
 3762                 return (priv_check_cred(cred, PRIV_VFS_EXTATTR_SYSTEM, 0));
 3763         case EXTATTR_NAMESPACE_USER:
 3764                 return (VOP_ACCESS(vp, accmode, cred, td));
 3765         default:
 3766                 return (EPERM);
 3767         }
 3768 }
 3769 
 3770 #ifdef DEBUG_VFS_LOCKS
 3771 /*
 3772  * This only exists to supress warnings from unlocked specfs accesses.  It is
 3773  * no longer ok to have an unlocked VFS.
 3774  */
 3775 #define IGNORE_LOCK(vp) (panicstr != NULL || (vp) == NULL ||            \
 3776         (vp)->v_type == VCHR || (vp)->v_type == VBAD)
 3777 
 3778 int vfs_badlock_ddb = 1;        /* Drop into debugger on violation. */
 3779 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0,
 3780     "Drop into debugger on lock violation");
 3781 
 3782 int vfs_badlock_mutex = 1;      /* Check for interlock across VOPs. */
 3783 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex,
 3784     0, "Check for interlock across VOPs");
 3785 
 3786 int vfs_badlock_print = 1;      /* Print lock violations. */
 3787 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print,
 3788     0, "Print lock violations");
 3789 
 3790 #ifdef KDB
 3791 int vfs_badlock_backtrace = 1;  /* Print backtrace at lock violations. */
 3792 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW,
 3793     &vfs_badlock_backtrace, 0, "Print backtrace at lock violations");
 3794 #endif
 3795 
 3796 static void
 3797 vfs_badlock(const char *msg, const char *str, struct vnode *vp)
 3798 {
 3799 
 3800 #ifdef KDB
 3801         if (vfs_badlock_backtrace)
 3802                 kdb_backtrace();
 3803 #endif
 3804         if (vfs_badlock_print)
 3805                 printf("%s: %p %s\n", str, (void *)vp, msg);
 3806         if (vfs_badlock_ddb)
 3807                 kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3808 }
 3809 
 3810 void
 3811 assert_vi_locked(struct vnode *vp, const char *str)
 3812 {
 3813 
 3814         if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
 3815                 vfs_badlock("interlock is not locked but should be", str, vp);
 3816 }
 3817 
 3818 void
 3819 assert_vi_unlocked(struct vnode *vp, const char *str)
 3820 {
 3821 
 3822         if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
 3823                 vfs_badlock("interlock is locked but should not be", str, vp);
 3824 }
 3825 
 3826 void
 3827 assert_vop_locked(struct vnode *vp, const char *str)
 3828 {
 3829 
 3830         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == 0)
 3831                 vfs_badlock("is not locked but should be", str, vp);
 3832 }
 3833 
 3834 void
 3835 assert_vop_unlocked(struct vnode *vp, const char *str)
 3836 {
 3837 
 3838         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
 3839                 vfs_badlock("is locked but should not be", str, vp);
 3840 }
 3841 
 3842 void
 3843 assert_vop_elocked(struct vnode *vp, const char *str)
 3844 {
 3845 
 3846         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 3847                 vfs_badlock("is not exclusive locked but should be", str, vp);
 3848 }
 3849 
 3850 #if 0
 3851 void
 3852 assert_vop_elocked_other(struct vnode *vp, const char *str)
 3853 {
 3854 
 3855         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLOTHER)
 3856                 vfs_badlock("is not exclusive locked by another thread",
 3857                     str, vp);
 3858 }
 3859 
 3860 void
 3861 assert_vop_slocked(struct vnode *vp, const char *str)
 3862 {
 3863 
 3864         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_SHARED)
 3865                 vfs_badlock("is not locked shared but should be", str, vp);
 3866 }
 3867 #endif /* 0 */
 3868 #endif /* DEBUG_VFS_LOCKS */
 3869 
 3870 void
 3871 vop_rename_fail(struct vop_rename_args *ap)
 3872 {
 3873 
 3874         if (ap->a_tvp != NULL)
 3875                 vput(ap->a_tvp);
 3876         if (ap->a_tdvp == ap->a_tvp)
 3877                 vrele(ap->a_tdvp);
 3878         else
 3879                 vput(ap->a_tdvp);
 3880         vrele(ap->a_fdvp);
 3881         vrele(ap->a_fvp);
 3882 }
 3883 
 3884 void
 3885 vop_rename_pre(void *ap)
 3886 {
 3887         struct vop_rename_args *a = ap;
 3888 
 3889 #ifdef DEBUG_VFS_LOCKS
 3890         if (a->a_tvp)
 3891                 ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
 3892         ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
 3893         ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
 3894         ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
 3895 
 3896         /* Check the source (from). */
 3897         if (a->a_tdvp->v_vnlock != a->a_fdvp->v_vnlock &&
 3898             (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fdvp->v_vnlock))
 3899                 ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
 3900         if (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fvp->v_vnlock)
 3901                 ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: fvp locked");
 3902 
 3903         /* Check the target. */
 3904         if (a->a_tvp)
 3905                 ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
 3906         ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
 3907 #endif
 3908         if (a->a_tdvp != a->a_fdvp)
 3909                 vhold(a->a_fdvp);
 3910         if (a->a_tvp != a->a_fvp)
 3911                 vhold(a->a_fvp);
 3912         vhold(a->a_tdvp);
 3913         if (a->a_tvp)
 3914                 vhold(a->a_tvp);
 3915 }
 3916 
 3917 void
 3918 vop_strategy_pre(void *ap)
 3919 {
 3920 #ifdef DEBUG_VFS_LOCKS
 3921         struct vop_strategy_args *a;
 3922         struct buf *bp;
 3923 
 3924         a = ap;
 3925         bp = a->a_bp;
 3926 
 3927         /*
 3928          * Cluster ops lock their component buffers but not the IO container.
 3929          */
 3930         if ((bp->b_flags & B_CLUSTER) != 0)
 3931                 return;
 3932 
 3933         if (panicstr == NULL && !BUF_ISLOCKED(bp)) {
 3934                 if (vfs_badlock_print)
 3935                         printf(
 3936                             "VOP_STRATEGY: bp is not locked but should be\n");
 3937                 if (vfs_badlock_ddb)
 3938                         kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3939         }
 3940 #endif
 3941 }
 3942 
 3943 void
 3944 vop_lookup_pre(void *ap)
 3945 {
 3946 #ifdef DEBUG_VFS_LOCKS
 3947         struct vop_lookup_args *a;
 3948         struct vnode *dvp;
 3949 
 3950         a = ap;
 3951         dvp = a->a_dvp;
 3952         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
 3953         ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
 3954 #endif
 3955 }
 3956 
 3957 void
 3958 vop_lookup_post(void *ap, int rc)
 3959 {
 3960 #ifdef DEBUG_VFS_LOCKS
 3961         struct vop_lookup_args *a;
 3962         struct vnode *dvp;
 3963         struct vnode *vp;
 3964 
 3965         a = ap;
 3966         dvp = a->a_dvp;
 3967         vp = *(a->a_vpp);
 3968 
 3969         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
 3970         ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
 3971 
 3972         if (!rc)
 3973                 ASSERT_VOP_LOCKED(vp, "VOP_LOOKUP (child)");
 3974 #endif
 3975 }
 3976 
 3977 void
 3978 vop_lock_pre(void *ap)
 3979 {
 3980 #ifdef DEBUG_VFS_LOCKS
 3981         struct vop_lock1_args *a = ap;
 3982 
 3983         if ((a->a_flags & LK_INTERLOCK) == 0)
 3984                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 3985         else
 3986                 ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
 3987 #endif
 3988 }
 3989 
 3990 void
 3991 vop_lock_post(void *ap, int rc)
 3992 {
 3993 #ifdef DEBUG_VFS_LOCKS
 3994         struct vop_lock1_args *a = ap;
 3995 
 3996         ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 3997         if (rc == 0)
 3998                 ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
 3999 #endif
 4000 }
 4001 
 4002 void
 4003 vop_unlock_pre(void *ap)
 4004 {
 4005 #ifdef DEBUG_VFS_LOCKS
 4006         struct vop_unlock_args *a = ap;
 4007 
 4008         if (a->a_flags & LK_INTERLOCK)
 4009                 ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
 4010         ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
 4011 #endif
 4012 }
 4013 
 4014 void
 4015 vop_unlock_post(void *ap, int rc)
 4016 {
 4017 #ifdef DEBUG_VFS_LOCKS
 4018         struct vop_unlock_args *a = ap;
 4019 
 4020         if (a->a_flags & LK_INTERLOCK)
 4021                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
 4022 #endif
 4023 }
 4024 
 4025 void
 4026 vop_create_post(void *ap, int rc)
 4027 {
 4028         struct vop_create_args *a = ap;
 4029 
 4030         if (!rc)
 4031                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4032 }
 4033 
 4034 void
 4035 vop_link_post(void *ap, int rc)
 4036 {
 4037         struct vop_link_args *a = ap;
 4038 
 4039         if (!rc) {
 4040                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_LINK);
 4041                 VFS_KNOTE_LOCKED(a->a_tdvp, NOTE_WRITE);
 4042         }
 4043 }
 4044 
 4045 void
 4046 vop_mkdir_post(void *ap, int rc)
 4047 {
 4048         struct vop_mkdir_args *a = ap;
 4049 
 4050         if (!rc)
 4051                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4052 }
 4053 
 4054 void
 4055 vop_mknod_post(void *ap, int rc)
 4056 {
 4057         struct vop_mknod_args *a = ap;
 4058 
 4059         if (!rc)
 4060                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4061 }
 4062 
 4063 void
 4064 vop_remove_post(void *ap, int rc)
 4065 {
 4066         struct vop_remove_args *a = ap;
 4067 
 4068         if (!rc) {
 4069                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4070                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4071         }
 4072 }
 4073 
 4074 void
 4075 vop_rename_post(void *ap, int rc)
 4076 {
 4077         struct vop_rename_args *a = ap;
 4078 
 4079         if (!rc) {
 4080                 VFS_KNOTE_UNLOCKED(a->a_fdvp, NOTE_WRITE);
 4081                 VFS_KNOTE_UNLOCKED(a->a_tdvp, NOTE_WRITE);
 4082                 VFS_KNOTE_UNLOCKED(a->a_fvp, NOTE_RENAME);
 4083                 if (a->a_tvp)
 4084                         VFS_KNOTE_UNLOCKED(a->a_tvp, NOTE_DELETE);
 4085         }
 4086         if (a->a_tdvp != a->a_fdvp)
 4087                 vdrop(a->a_fdvp);
 4088         if (a->a_tvp != a->a_fvp)
 4089                 vdrop(a->a_fvp);
 4090         vdrop(a->a_tdvp);
 4091         if (a->a_tvp)
 4092                 vdrop(a->a_tvp);
 4093 }
 4094 
 4095 void
 4096 vop_rmdir_post(void *ap, int rc)
 4097 {
 4098         struct vop_rmdir_args *a = ap;
 4099 
 4100         if (!rc) {
 4101                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4102                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4103         }
 4104 }
 4105 
 4106 void
 4107 vop_setattr_post(void *ap, int rc)
 4108 {
 4109         struct vop_setattr_args *a = ap;
 4110 
 4111         if (!rc)
 4112                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4113 }
 4114 
 4115 void
 4116 vop_symlink_post(void *ap, int rc)
 4117 {
 4118         struct vop_symlink_args *a = ap;
 4119 
 4120         if (!rc)
 4121                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4122 }
 4123 
 4124 static struct knlist fs_knlist;
 4125 
 4126 static void
 4127 vfs_event_init(void *arg)
 4128 {
 4129         knlist_init_mtx(&fs_knlist, NULL);
 4130 }
 4131 /* XXX - correct order? */
 4132 SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
 4133 
 4134 void
 4135 vfs_event_signal(fsid_t *fsid, uint32_t event, intptr_t data __unused)
 4136 {
 4137 
 4138         KNOTE_UNLOCKED(&fs_knlist, event);
 4139 }
 4140 
 4141 static int      filt_fsattach(struct knote *kn);
 4142 static void     filt_fsdetach(struct knote *kn);
 4143 static int      filt_fsevent(struct knote *kn, long hint);
 4144 
 4145 struct filterops fs_filtops = {
 4146         .f_isfd = 0,
 4147         .f_attach = filt_fsattach,
 4148         .f_detach = filt_fsdetach,
 4149         .f_event = filt_fsevent
 4150 };
 4151 
 4152 static int
 4153 filt_fsattach(struct knote *kn)
 4154 {
 4155 
 4156         kn->kn_flags |= EV_CLEAR;
 4157         knlist_add(&fs_knlist, kn, 0);
 4158         return (0);
 4159 }
 4160 
 4161 static void
 4162 filt_fsdetach(struct knote *kn)
 4163 {
 4164 
 4165         knlist_remove(&fs_knlist, kn, 0);
 4166 }
 4167 
 4168 static int
 4169 filt_fsevent(struct knote *kn, long hint)
 4170 {
 4171 
 4172         kn->kn_fflags |= hint;
 4173         return (kn->kn_fflags != 0);
 4174 }
 4175 
 4176 static int
 4177 sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
 4178 {
 4179         struct vfsidctl vc;
 4180         int error;
 4181         struct mount *mp;
 4182 
 4183         error = SYSCTL_IN(req, &vc, sizeof(vc));
 4184         if (error)
 4185                 return (error);
 4186         if (vc.vc_vers != VFS_CTL_VERS1)
 4187                 return (EINVAL);
 4188         mp = vfs_getvfs(&vc.vc_fsid);
 4189         if (mp == NULL)
 4190                 return (ENOENT);
 4191         /* ensure that a specific sysctl goes to the right filesystem. */
 4192         if (strcmp(vc.vc_fstypename, "*") != 0 &&
 4193             strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
 4194                 vfs_rel(mp);
 4195                 return (EINVAL);
 4196         }
 4197         VCTLTOREQ(&vc, req);
 4198         error = VFS_SYSCTL(mp, vc.vc_op, req);
 4199         vfs_rel(mp);
 4200         return (error);
 4201 }
 4202 
 4203 SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLTYPE_OPAQUE | CTLFLAG_WR,
 4204     NULL, 0, sysctl_vfs_ctl, "",
 4205     "Sysctl by fsid");
 4206 
 4207 /*
 4208  * Function to initialize a va_filerev field sensibly.
 4209  * XXX: Wouldn't a random number make a lot more sense ??
 4210  */
 4211 u_quad_t
 4212 init_va_filerev(void)
 4213 {
 4214         struct bintime bt;
 4215 
 4216         getbinuptime(&bt);
 4217         return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
 4218 }
 4219 
 4220 static int      filt_vfsread(struct knote *kn, long hint);
 4221 static int      filt_vfswrite(struct knote *kn, long hint);
 4222 static int      filt_vfsvnode(struct knote *kn, long hint);
 4223 static void     filt_vfsdetach(struct knote *kn);
 4224 static struct filterops vfsread_filtops = {
 4225         .f_isfd = 1,
 4226         .f_detach = filt_vfsdetach,
 4227         .f_event = filt_vfsread
 4228 };
 4229 static struct filterops vfswrite_filtops = {
 4230         .f_isfd = 1,
 4231         .f_detach = filt_vfsdetach,
 4232         .f_event = filt_vfswrite
 4233 };
 4234 static struct filterops vfsvnode_filtops = {
 4235         .f_isfd = 1,
 4236         .f_detach = filt_vfsdetach,
 4237         .f_event = filt_vfsvnode
 4238 };
 4239 
 4240 static void
 4241 vfs_knllock(void *arg)
 4242 {
 4243         struct vnode *vp = arg;
 4244 
 4245         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 4246 }
 4247 
 4248 static void
 4249 vfs_knlunlock(void *arg)
 4250 {
 4251         struct vnode *vp = arg;
 4252 
 4253         VOP_UNLOCK(vp, 0);
 4254 }
 4255 
 4256 static void
 4257 vfs_knl_assert_locked(void *arg)
 4258 {
 4259 #ifdef DEBUG_VFS_LOCKS
 4260         struct vnode *vp = arg;
 4261 
 4262         ASSERT_VOP_LOCKED(vp, "vfs_knl_assert_locked");
 4263 #endif
 4264 }
 4265 
 4266 static void
 4267 vfs_knl_assert_unlocked(void *arg)
 4268 {
 4269 #ifdef DEBUG_VFS_LOCKS
 4270         struct vnode *vp = arg;
 4271 
 4272         ASSERT_VOP_UNLOCKED(vp, "vfs_knl_assert_unlocked");
 4273 #endif
 4274 }
 4275 
 4276 int
 4277 vfs_kqfilter(struct vop_kqfilter_args *ap)
 4278 {
 4279         struct vnode *vp = ap->a_vp;
 4280         struct knote *kn = ap->a_kn;
 4281         struct knlist *knl;
 4282 
 4283         switch (kn->kn_filter) {
 4284         case EVFILT_READ:
 4285                 kn->kn_fop = &vfsread_filtops;
 4286                 break;
 4287         case EVFILT_WRITE:
 4288                 kn->kn_fop = &vfswrite_filtops;
 4289                 break;
 4290         case EVFILT_VNODE:
 4291                 kn->kn_fop = &vfsvnode_filtops;
 4292                 break;
 4293         default:
 4294                 return (EINVAL);
 4295         }
 4296 
 4297         kn->kn_hook = (caddr_t)vp;
 4298 
 4299         v_addpollinfo(vp);
 4300         if (vp->v_pollinfo == NULL)
 4301                 return (ENOMEM);
 4302         knl = &vp->v_pollinfo->vpi_selinfo.si_note;
 4303         knlist_add(knl, kn, 0);
 4304 
 4305         return (0);
 4306 }
 4307 
 4308 /*
 4309  * Detach knote from vnode
 4310  */
 4311 static void
 4312 filt_vfsdetach(struct knote *kn)
 4313 {
 4314         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4315 
 4316         KASSERT(vp->v_pollinfo != NULL, ("Missing v_pollinfo"));
 4317         knlist_remove(&vp->v_pollinfo->vpi_selinfo.si_note, kn, 0);
 4318 }
 4319 
 4320 /*ARGSUSED*/
 4321 static int
 4322 filt_vfsread(struct knote *kn, long hint)
 4323 {
 4324         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4325         struct vattr va;
 4326         int res;
 4327 
 4328         /*
 4329          * filesystem is gone, so set the EOF flag and schedule
 4330          * the knote for deletion.
 4331          */
 4332         if (hint == NOTE_REVOKE) {
 4333                 VI_LOCK(vp);
 4334                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4335                 VI_UNLOCK(vp);
 4336                 return (1);
 4337         }
 4338 
 4339         if (VOP_GETATTR(vp, &va, curthread->td_ucred))
 4340                 return (0);
 4341 
 4342         VI_LOCK(vp);
 4343         kn->kn_data = va.va_size - kn->kn_fp->f_offset;
 4344         res = (kn->kn_data != 0);
 4345         VI_UNLOCK(vp);
 4346         return (res);
 4347 }
 4348 
 4349 /*ARGSUSED*/
 4350 static int
 4351 filt_vfswrite(struct knote *kn, long hint)
 4352 {
 4353         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4354 
 4355         VI_LOCK(vp);
 4356 
 4357         /*
 4358          * filesystem is gone, so set the EOF flag and schedule
 4359          * the knote for deletion.
 4360          */
 4361         if (hint == NOTE_REVOKE)
 4362                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4363 
 4364         kn->kn_data = 0;
 4365         VI_UNLOCK(vp);
 4366         return (1);
 4367 }
 4368 
 4369 static int
 4370 filt_vfsvnode(struct knote *kn, long hint)
 4371 {
 4372         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4373         int res;
 4374 
 4375         VI_LOCK(vp);
 4376         if (kn->kn_sfflags & hint)
 4377                 kn->kn_fflags |= hint;
 4378         if (hint == NOTE_REVOKE) {
 4379                 kn->kn_flags |= EV_EOF;
 4380                 VI_UNLOCK(vp);
 4381                 return (1);
 4382         }
 4383         res = (kn->kn_fflags != 0);
 4384         VI_UNLOCK(vp);
 4385         return (res);
 4386 }
 4387 
 4388 int
 4389 vfs_read_dirent(struct vop_readdir_args *ap, struct dirent *dp, off_t off)
 4390 {
 4391         int error;
 4392 
 4393         if (dp->d_reclen > ap->a_uio->uio_resid)
 4394                 return (ENAMETOOLONG);
 4395         error = uiomove(dp, dp->d_reclen, ap->a_uio);
 4396         if (error) {
 4397                 if (ap->a_ncookies != NULL) {
 4398                         if (ap->a_cookies != NULL)
 4399                                 free(ap->a_cookies, M_TEMP);
 4400                         ap->a_cookies = NULL;
 4401                         *ap->a_ncookies = 0;
 4402                 }
 4403                 return (error);
 4404         }
 4405         if (ap->a_ncookies == NULL)
 4406                 return (0);
 4407 
 4408         KASSERT(ap->a_cookies,
 4409             ("NULL ap->a_cookies value with non-NULL ap->a_ncookies!"));
 4410 
 4411         *ap->a_cookies = realloc(*ap->a_cookies,
 4412             (*ap->a_ncookies + 1) * sizeof(u_long), M_TEMP, M_WAITOK | M_ZERO);
 4413         (*ap->a_cookies)[*ap->a_ncookies] = off;
 4414         return (0);
 4415 }
 4416 
 4417 /*
 4418  * Mark for update the access time of the file if the filesystem
 4419  * supports VOP_MARKATIME.  This functionality is used by execve and
 4420  * mmap, so we want to avoid the I/O implied by directly setting
 4421  * va_atime for the sake of efficiency.
 4422  */
 4423 void
 4424 vfs_mark_atime(struct vnode *vp, struct ucred *cred)
 4425 {
 4426         struct mount *mp;
 4427 
 4428         mp = vp->v_mount;
 4429         VFS_ASSERT_GIANT(mp);
 4430         ASSERT_VOP_LOCKED(vp, "vfs_mark_atime");
 4431         if (mp != NULL && (mp->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0)
 4432                 (void)VOP_MARKATIME(vp);
 4433 }
 4434 
 4435 /*
 4436  * The purpose of this routine is to remove granularity from accmode_t,
 4437  * reducing it into standard unix access bits - VEXEC, VREAD, VWRITE,
 4438  * VADMIN and VAPPEND.
 4439  *
 4440  * If it returns 0, the caller is supposed to continue with the usual
 4441  * access checks using 'accmode' as modified by this routine.  If it
 4442  * returns nonzero value, the caller is supposed to return that value
 4443  * as errno.
 4444  *
 4445  * Note that after this routine runs, accmode may be zero.
 4446  */
 4447 int
 4448 vfs_unixify_accmode(accmode_t *accmode)
 4449 {
 4450         /*
 4451          * There is no way to specify explicit "deny" rule using
 4452          * file mode or POSIX.1e ACLs.
 4453          */
 4454         if (*accmode & VEXPLICIT_DENY) {
 4455                 *accmode = 0;
 4456                 return (0);
 4457         }
 4458 
 4459         /*
 4460          * None of these can be translated into usual access bits.
 4461          * Also, the common case for NFSv4 ACLs is to not contain
 4462          * either of these bits. Caller should check for VWRITE
 4463          * on the containing directory instead.
 4464          */
 4465         if (*accmode & (VDELETE_CHILD | VDELETE))
 4466                 return (EPERM);
 4467 
 4468         if (*accmode & VADMIN_PERMS) {
 4469                 *accmode &= ~VADMIN_PERMS;
 4470                 *accmode |= VADMIN;
 4471         }
 4472 
 4473         /*
 4474          * There is no way to deny VREAD_ATTRIBUTES, VREAD_ACL
 4475          * or VSYNCHRONIZE using file mode or POSIX.1e ACL.
 4476          */
 4477         *accmode &= ~(VSTAT_PERMS | VSYNCHRONIZE);
 4478 
 4479         return (0);
 4480 }

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