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


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

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

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)vfs_subr.c  8.31 (Berkeley) 5/26/95
   35  */
   36 
   37 /*
   38  * External virtual filesystem routines
   39  */
   40 
   41 #include <sys/cdefs.h>
   42 __FBSDID("$FreeBSD: releng/8.3/sys/kern/vfs_subr.c 231948 2012-02-21 00:32:24Z 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_LONG(_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_LONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
  155 /* Number of vnodes in the free list. */
  156 static u_long freevnodes;
  157 SYSCTL_LONG(_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 /* Set to 1 to print out reclaim of active vnodes */
  198 int     prtactive;
  199 
  200 /*
  201  * The workitem queue.
  202  *
  203  * It is useful to delay writes of file data and filesystem metadata
  204  * for tens of seconds so that quickly created and deleted files need
  205  * not waste disk bandwidth being created and removed. To realize this,
  206  * we append vnodes to a "workitem" queue. When running with a soft
  207  * updates implementation, most pending metadata dependencies should
  208  * not wait for more than a few seconds. Thus, mounted on block devices
  209  * are delayed only about a half the time that file data is delayed.
  210  * Similarly, directory updates are more critical, so are only delayed
  211  * about a third the time that file data is delayed. Thus, there are
  212  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
  213  * one each second (driven off the filesystem syncer process). The
  214  * syncer_delayno variable indicates the next queue that is to be processed.
  215  * Items that need to be processed soon are placed in this queue:
  216  *
  217  *      syncer_workitem_pending[syncer_delayno]
  218  *
  219  * A delay of fifteen seconds is done by placing the request fifteen
  220  * entries later in the queue:
  221  *
  222  *      syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
  223  *
  224  */
  225 static int syncer_delayno;
  226 static long syncer_mask;
  227 LIST_HEAD(synclist, bufobj);
  228 static struct synclist *syncer_workitem_pending[2];
  229 /*
  230  * The sync_mtx protects:
  231  *      bo->bo_synclist
  232  *      sync_vnode_count
  233  *      syncer_delayno
  234  *      syncer_state
  235  *      syncer_workitem_pending
  236  *      syncer_worklist_len
  237  *      rushjob
  238  */
  239 static struct mtx sync_mtx;
  240 static struct cv sync_wakeup;
  241 
  242 #define SYNCER_MAXDELAY         32
  243 static int syncer_maxdelay = SYNCER_MAXDELAY;   /* maximum delay time */
  244 static int syncdelay = 30;              /* max time to delay syncing data */
  245 static int filedelay = 30;              /* time to delay syncing files */
  246 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0,
  247     "Time to delay syncing files (in seconds)");
  248 static int dirdelay = 29;               /* time to delay syncing directories */
  249 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0,
  250     "Time to delay syncing directories (in seconds)");
  251 static int metadelay = 28;              /* time to delay syncing metadata */
  252 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0,
  253     "Time to delay syncing metadata (in seconds)");
  254 static int rushjob;             /* number of slots to run ASAP */
  255 static int stat_rush_requests;  /* number of times I/O speeded up */
  256 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0,
  257     "Number of times I/O speeded up (rush requests)");
  258 
  259 /*
  260  * When shutting down the syncer, run it at four times normal speed.
  261  */
  262 #define SYNCER_SHUTDOWN_SPEEDUP         4
  263 static int sync_vnode_count;
  264 static int syncer_worklist_len;
  265 static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
  266     syncer_state;
  267 
  268 /*
  269  * Number of vnodes we want to exist at any one time.  This is mostly used
  270  * to size hash tables in vnode-related code.  It is normally not used in
  271  * getnewvnode(), as wantfreevnodes is normally nonzero.)
  272  *
  273  * XXX desiredvnodes is historical cruft and should not exist.
  274  */
  275 int desiredvnodes;
  276 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
  277     &desiredvnodes, 0, "Maximum number of vnodes");
  278 SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
  279     &wantfreevnodes, 0, "Minimum number of vnodes (legacy)");
  280 static int vnlru_nowhere;
  281 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
  282     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
  283 
  284 /*
  285  * Macros to control when a vnode is freed and recycled.  All require
  286  * the vnode interlock.
  287  */
  288 #define VCANRECYCLE(vp) (((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  289 #define VSHOULDFREE(vp) (!((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
  290 #define VSHOULDBUSY(vp) (((vp)->v_iflag & VI_FREE) && (vp)->v_holdcnt)
  291 
  292 
  293 /*
  294  * Initialize the vnode management data structures.
  295  *
  296  * Reevaluate the following cap on the number of vnodes after the physical
  297  * memory size exceeds 512GB.  In the limit, as the physical memory size
  298  * grows, the ratio of physical pages to vnodes approaches sixteen to one.
  299  */
  300 #ifndef MAXVNODES_MAX
  301 #define MAXVNODES_MAX   (512 * (1024 * 1024 * 1024 / (int)PAGE_SIZE / 16))
  302 #endif
  303 static void
  304 vntblinit(void *dummy __unused)
  305 {
  306         int physvnodes, virtvnodes;
  307 
  308         /*
  309          * Desiredvnodes is a function of the physical memory size and the
  310          * kernel's heap size.  Generally speaking, it scales with the
  311          * physical memory size.  The ratio of desiredvnodes to physical pages
  312          * is one to four until desiredvnodes exceeds 98,304.  Thereafter, the
  313          * marginal ratio of desiredvnodes to physical pages is one to
  314          * sixteen.  However, desiredvnodes is limited by the kernel's heap
  315          * size.  The memory required by desiredvnodes vnodes and vm objects
  316          * may not exceed one seventh of the kernel's heap size.
  317          */
  318         physvnodes = maxproc + cnt.v_page_count / 16 + 3 * min(98304 * 4,
  319             cnt.v_page_count) / 16;
  320         virtvnodes = vm_kmem_size / (7 * (sizeof(struct vm_object) +
  321             sizeof(struct vnode)));
  322         desiredvnodes = min(physvnodes, virtvnodes);
  323         if (desiredvnodes > MAXVNODES_MAX) {
  324                 if (bootverbose)
  325                         printf("Reducing kern.maxvnodes %d -> %d\n",
  326                             desiredvnodes, MAXVNODES_MAX);
  327                 desiredvnodes = MAXVNODES_MAX;
  328         }
  329         wantfreevnodes = desiredvnodes / 4;
  330         mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
  331         TAILQ_INIT(&vnode_free_list);
  332         mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
  333         vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
  334             NULL, NULL, UMA_ALIGN_PTR, 0);
  335         vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
  336             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  337         /*
  338          * Initialize the filesystem syncer.
  339          */
  340         syncer_workitem_pending[WI_MPSAFEQ] = hashinit(syncer_maxdelay, M_VNODE,
  341             &syncer_mask);
  342         syncer_workitem_pending[WI_GIANTQ] = hashinit(syncer_maxdelay, M_VNODE,
  343             &syncer_mask);
  344         syncer_maxdelay = syncer_mask + 1;
  345         mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
  346         cv_init(&sync_wakeup, "syncer");
  347 }
  348 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL);
  349 
  350 
  351 /*
  352  * Mark a mount point as busy. Used to synchronize access and to delay
  353  * unmounting. Eventually, mountlist_mtx is not released on failure.
  354  *
  355  * vfs_busy() is a custom lock, it can block the caller.
  356  * vfs_busy() only sleeps if the unmount is active on the mount point.
  357  * For a mountpoint mp, vfs_busy-enforced lock is before lock of any
  358  * vnode belonging to mp.
  359  *
  360  * Lookup uses vfs_busy() to traverse mount points.
  361  * root fs                      var fs
  362  * / vnode lock         A       / vnode lock (/var)             D
  363  * /var vnode lock      B       /log vnode lock(/var/log)       E
  364  * vfs_busy lock        C       vfs_busy lock                   F
  365  *
  366  * Within each file system, the lock order is C->A->B and F->D->E.
  367  *
  368  * When traversing across mounts, the system follows that lock order:
  369  *
  370  *        C->A->B
  371  *              |
  372  *              +->F->D->E
  373  *
  374  * The lookup() process for namei("/var") illustrates the process:
  375  *  VOP_LOOKUP() obtains B while A is held
  376  *  vfs_busy() obtains a shared lock on F while A and B are held
  377  *  vput() releases lock on B
  378  *  vput() releases lock on A
  379  *  VFS_ROOT() obtains lock on D while shared lock on F is held
  380  *  vfs_unbusy() releases shared lock on F
  381  *  vn_lock() obtains lock on deadfs vnode vp_crossmp instead of A.
  382  *    Attempt to lock A (instead of vp_crossmp) while D is held would
  383  *    violate the global order, causing deadlocks.
  384  *
  385  * dounmount() locks B while F is drained.
  386  */
  387 int
  388 vfs_busy(struct mount *mp, int flags)
  389 {
  390 
  391         MPASS((flags & ~MBF_MASK) == 0);
  392         CTR3(KTR_VFS, "%s: mp %p with flags %d", __func__, mp, flags);
  393 
  394         MNT_ILOCK(mp);
  395         MNT_REF(mp);
  396         /*
  397          * If mount point is currenly being unmounted, sleep until the
  398          * mount point fate is decided.  If thread doing the unmounting fails,
  399          * it will clear MNTK_UNMOUNT flag before waking us up, indicating
  400          * that this mount point has survived the unmount attempt and vfs_busy
  401          * should retry.  Otherwise the unmounter thread will set MNTK_REFEXPIRE
  402          * flag in addition to MNTK_UNMOUNT, indicating that mount point is
  403          * about to be really destroyed.  vfs_busy needs to release its
  404          * reference on the mount point in this case and return with ENOENT,
  405          * telling the caller that mount mount it tried to busy is no longer
  406          * valid.
  407          */
  408         while (mp->mnt_kern_flag & MNTK_UNMOUNT) {
  409                 if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) {
  410                         MNT_REL(mp);
  411                         MNT_IUNLOCK(mp);
  412                         CTR1(KTR_VFS, "%s: failed busying before sleeping",
  413                             __func__);
  414                         return (ENOENT);
  415                 }
  416                 if (flags & MBF_MNTLSTLOCK)
  417                         mtx_unlock(&mountlist_mtx);
  418                 mp->mnt_kern_flag |= MNTK_MWAIT;
  419                 msleep(mp, MNT_MTX(mp), PVFS | PDROP, "vfs_busy", 0);
  420                 if (flags & MBF_MNTLSTLOCK)
  421                         mtx_lock(&mountlist_mtx);
  422                 MNT_ILOCK(mp);
  423         }
  424         if (flags & MBF_MNTLSTLOCK)
  425                 mtx_unlock(&mountlist_mtx);
  426         mp->mnt_lockref++;
  427         MNT_IUNLOCK(mp);
  428         return (0);
  429 }
  430 
  431 /*
  432  * Free a busy filesystem.
  433  */
  434 void
  435 vfs_unbusy(struct mount *mp)
  436 {
  437 
  438         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  439         MNT_ILOCK(mp);
  440         MNT_REL(mp);
  441         KASSERT(mp->mnt_lockref > 0, ("negative mnt_lockref"));
  442         mp->mnt_lockref--;
  443         if (mp->mnt_lockref == 0 && (mp->mnt_kern_flag & MNTK_DRAINING) != 0) {
  444                 MPASS(mp->mnt_kern_flag & MNTK_UNMOUNT);
  445                 CTR1(KTR_VFS, "%s: waking up waiters", __func__);
  446                 mp->mnt_kern_flag &= ~MNTK_DRAINING;
  447                 wakeup(&mp->mnt_lockref);
  448         }
  449         MNT_IUNLOCK(mp);
  450 }
  451 
  452 /*
  453  * Lookup a mount point by filesystem identifier.
  454  */
  455 struct mount *
  456 vfs_getvfs(fsid_t *fsid)
  457 {
  458         struct mount *mp;
  459 
  460         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  461         mtx_lock(&mountlist_mtx);
  462         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  463                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  464                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  465                         vfs_ref(mp);
  466                         mtx_unlock(&mountlist_mtx);
  467                         return (mp);
  468                 }
  469         }
  470         mtx_unlock(&mountlist_mtx);
  471         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  472         return ((struct mount *) 0);
  473 }
  474 
  475 /*
  476  * Lookup a mount point by filesystem identifier, busying it before
  477  * returning.
  478  */
  479 struct mount *
  480 vfs_busyfs(fsid_t *fsid)
  481 {
  482         struct mount *mp;
  483         int error;
  484 
  485         CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
  486         mtx_lock(&mountlist_mtx);
  487         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
  488                 if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
  489                     mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
  490                         error = vfs_busy(mp, MBF_MNTLSTLOCK);
  491                         if (error) {
  492                                 mtx_unlock(&mountlist_mtx);
  493                                 return (NULL);
  494                         }
  495                         return (mp);
  496                 }
  497         }
  498         CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
  499         mtx_unlock(&mountlist_mtx);
  500         return ((struct mount *) 0);
  501 }
  502 
  503 /*
  504  * Check if a user can access privileged mount options.
  505  */
  506 int
  507 vfs_suser(struct mount *mp, struct thread *td)
  508 {
  509         int error;
  510 
  511         /*
  512          * If the thread is jailed, but this is not a jail-friendly file
  513          * system, deny immediately.
  514          */
  515         if (!(mp->mnt_vfc->vfc_flags & VFCF_JAIL) && jailed(td->td_ucred))
  516                 return (EPERM);
  517 
  518         /*
  519          * If the file system was mounted outside the jail of the calling
  520          * thread, deny immediately.
  521          */
  522         if (prison_check(td->td_ucred, mp->mnt_cred) != 0)
  523                 return (EPERM);
  524 
  525         /*
  526          * If file system supports delegated administration, we don't check
  527          * for the PRIV_VFS_MOUNT_OWNER privilege - it will be better verified
  528          * by the file system itself.
  529          * If this is not the user that did original mount, we check for
  530          * the PRIV_VFS_MOUNT_OWNER privilege.
  531          */
  532         if (!(mp->mnt_vfc->vfc_flags & VFCF_DELEGADMIN) &&
  533             mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
  534                 if ((error = priv_check(td, PRIV_VFS_MOUNT_OWNER)) != 0)
  535                         return (error);
  536         }
  537         return (0);
  538 }
  539 
  540 /*
  541  * Get a new unique fsid.  Try to make its val[0] unique, since this value
  542  * will be used to create fake device numbers for stat().  Also try (but
  543  * not so hard) make its val[0] unique mod 2^16, since some emulators only
  544  * support 16-bit device numbers.  We end up with unique val[0]'s for the
  545  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
  546  *
  547  * Keep in mind that several mounts may be running in parallel.  Starting
  548  * the search one past where the previous search terminated is both a
  549  * micro-optimization and a defense against returning the same fsid to
  550  * different mounts.
  551  */
  552 void
  553 vfs_getnewfsid(struct mount *mp)
  554 {
  555         static u_int16_t mntid_base;
  556         struct mount *nmp;
  557         fsid_t tfsid;
  558         int mtype;
  559 
  560         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  561         mtx_lock(&mntid_mtx);
  562         mtype = mp->mnt_vfc->vfc_typenum;
  563         tfsid.val[1] = mtype;
  564         mtype = (mtype & 0xFF) << 24;
  565         for (;;) {
  566                 tfsid.val[0] = makedev(255,
  567                     mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
  568                 mntid_base++;
  569                 if ((nmp = vfs_getvfs(&tfsid)) == NULL)
  570                         break;
  571                 vfs_rel(nmp);
  572         }
  573         mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
  574         mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
  575         mtx_unlock(&mntid_mtx);
  576 }
  577 
  578 /*
  579  * Knob to control the precision of file timestamps:
  580  *
  581  *   0 = seconds only; nanoseconds zeroed.
  582  *   1 = seconds and nanoseconds, accurate within 1/HZ.
  583  *   2 = seconds and nanoseconds, truncated to microseconds.
  584  * >=3 = seconds and nanoseconds, maximum precision.
  585  */
  586 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
  587 
  588 static int timestamp_precision = TSP_SEC;
  589 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
  590     &timestamp_precision, 0, "File timestamp precision (0: seconds, "
  591     "1: sec + ns accurate to 1/HZ, 2: sec + ns truncated to ms, "
  592     "3+: sec + ns (max. precision))");
  593 
  594 /*
  595  * Get a current timestamp.
  596  */
  597 void
  598 vfs_timestamp(struct timespec *tsp)
  599 {
  600         struct timeval tv;
  601 
  602         switch (timestamp_precision) {
  603         case TSP_SEC:
  604                 tsp->tv_sec = time_second;
  605                 tsp->tv_nsec = 0;
  606                 break;
  607         case TSP_HZ:
  608                 getnanotime(tsp);
  609                 break;
  610         case TSP_USEC:
  611                 microtime(&tv);
  612                 TIMEVAL_TO_TIMESPEC(&tv, tsp);
  613                 break;
  614         case TSP_NSEC:
  615         default:
  616                 nanotime(tsp);
  617                 break;
  618         }
  619 }
  620 
  621 /*
  622  * Set vnode attributes to VNOVAL
  623  */
  624 void
  625 vattr_null(struct vattr *vap)
  626 {
  627 
  628         vap->va_type = VNON;
  629         vap->va_size = VNOVAL;
  630         vap->va_bytes = VNOVAL;
  631         vap->va_mode = VNOVAL;
  632         vap->va_nlink = VNOVAL;
  633         vap->va_uid = VNOVAL;
  634         vap->va_gid = VNOVAL;
  635         vap->va_fsid = VNOVAL;
  636         vap->va_fileid = VNOVAL;
  637         vap->va_blocksize = VNOVAL;
  638         vap->va_rdev = VNOVAL;
  639         vap->va_atime.tv_sec = VNOVAL;
  640         vap->va_atime.tv_nsec = VNOVAL;
  641         vap->va_mtime.tv_sec = VNOVAL;
  642         vap->va_mtime.tv_nsec = VNOVAL;
  643         vap->va_ctime.tv_sec = VNOVAL;
  644         vap->va_ctime.tv_nsec = VNOVAL;
  645         vap->va_birthtime.tv_sec = VNOVAL;
  646         vap->va_birthtime.tv_nsec = VNOVAL;
  647         vap->va_flags = VNOVAL;
  648         vap->va_gen = VNOVAL;
  649         vap->va_vaflags = 0;
  650 }
  651 
  652 /*
  653  * This routine is called when we have too many vnodes.  It attempts
  654  * to free <count> vnodes and will potentially free vnodes that still
  655  * have VM backing store (VM backing store is typically the cause
  656  * of a vnode blowout so we want to do this).  Therefore, this operation
  657  * is not considered cheap.
  658  *
  659  * A number of conditions may prevent a vnode from being reclaimed.
  660  * the buffer cache may have references on the vnode, a directory
  661  * vnode may still have references due to the namei cache representing
  662  * underlying files, or the vnode may be in active use.   It is not
  663  * desireable to reuse such vnodes.  These conditions may cause the
  664  * number of vnodes to reach some minimum value regardless of what
  665  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
  666  */
  667 static int
  668 vlrureclaim(struct mount *mp)
  669 {
  670         struct vnode *vp;
  671         int done;
  672         int trigger;
  673         int usevnodes;
  674         int count;
  675 
  676         /*
  677          * Calculate the trigger point, don't allow user
  678          * screwups to blow us up.   This prevents us from
  679          * recycling vnodes with lots of resident pages.  We
  680          * aren't trying to free memory, we are trying to
  681          * free vnodes.
  682          */
  683         usevnodes = desiredvnodes;
  684         if (usevnodes <= 0)
  685                 usevnodes = 1;
  686         trigger = cnt.v_page_count * 2 / usevnodes;
  687         done = 0;
  688         vn_start_write(NULL, &mp, V_WAIT);
  689         MNT_ILOCK(mp);
  690         count = mp->mnt_nvnodelistsize / 10 + 1;
  691         while (count != 0) {
  692                 vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
  693                 while (vp != NULL && vp->v_type == VMARKER)
  694                         vp = TAILQ_NEXT(vp, v_nmntvnodes);
  695                 if (vp == NULL)
  696                         break;
  697                 TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  698                 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
  699                 --count;
  700                 if (!VI_TRYLOCK(vp))
  701                         goto next_iter;
  702                 /*
  703                  * If it's been deconstructed already, it's still
  704                  * referenced, or it exceeds the trigger, skip it.
  705                  */
  706                 if (vp->v_usecount ||
  707                     (!vlru_allow_cache_src &&
  708                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  709                     (vp->v_iflag & VI_DOOMED) != 0 || (vp->v_object != NULL &&
  710                     vp->v_object->resident_page_count > trigger)) {
  711                         VI_UNLOCK(vp);
  712                         goto next_iter;
  713                 }
  714                 MNT_IUNLOCK(mp);
  715                 vholdl(vp);
  716                 if (VOP_LOCK(vp, LK_INTERLOCK|LK_EXCLUSIVE|LK_NOWAIT)) {
  717                         vdrop(vp);
  718                         goto next_iter_mntunlocked;
  719                 }
  720                 VI_LOCK(vp);
  721                 /*
  722                  * v_usecount may have been bumped after VOP_LOCK() dropped
  723                  * the vnode interlock and before it was locked again.
  724                  *
  725                  * It is not necessary to recheck VI_DOOMED because it can
  726                  * only be set by another thread that holds both the vnode
  727                  * lock and vnode interlock.  If another thread has the
  728                  * vnode lock before we get to VOP_LOCK() and obtains the
  729                  * vnode interlock after VOP_LOCK() drops the vnode
  730                  * interlock, the other thread will be unable to drop the
  731                  * vnode lock before our VOP_LOCK() call fails.
  732                  */
  733                 if (vp->v_usecount ||
  734                     (!vlru_allow_cache_src &&
  735                         !LIST_EMPTY(&(vp)->v_cache_src)) ||
  736                     (vp->v_object != NULL &&
  737                     vp->v_object->resident_page_count > trigger)) {
  738                         VOP_UNLOCK(vp, LK_INTERLOCK);
  739                         goto next_iter_mntunlocked;
  740                 }
  741                 KASSERT((vp->v_iflag & VI_DOOMED) == 0,
  742                     ("VI_DOOMED unexpectedly detected in vlrureclaim()"));
  743                 vgonel(vp);
  744                 VOP_UNLOCK(vp, 0);
  745                 vdropl(vp);
  746                 done++;
  747 next_iter_mntunlocked:
  748                 if ((count % 256) != 0)
  749                         goto relock_mnt;
  750                 goto yield;
  751 next_iter:
  752                 if ((count % 256) != 0)
  753                         continue;
  754                 MNT_IUNLOCK(mp);
  755 yield:
  756                 uio_yield();
  757 relock_mnt:
  758                 MNT_ILOCK(mp);
  759         }
  760         MNT_IUNLOCK(mp);
  761         vn_finished_write(mp);
  762         return done;
  763 }
  764 
  765 /*
  766  * Attempt to keep the free list at wantfreevnodes length.
  767  */
  768 static void
  769 vnlru_free(int count)
  770 {
  771         struct vnode *vp;
  772         int vfslocked;
  773 
  774         mtx_assert(&vnode_free_list_mtx, MA_OWNED);
  775         for (; count > 0; count--) {
  776                 vp = TAILQ_FIRST(&vnode_free_list);
  777                 /*
  778                  * The list can be modified while the free_list_mtx
  779                  * has been dropped and vp could be NULL here.
  780                  */
  781                 if (!vp)
  782                         break;
  783                 VNASSERT(vp->v_op != NULL, vp,
  784                     ("vnlru_free: vnode already reclaimed."));
  785                 TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
  786                 /*
  787                  * Don't recycle if we can't get the interlock.
  788                  */
  789                 if (!VI_TRYLOCK(vp)) {
  790                         TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
  791                         continue;
  792                 }
  793                 VNASSERT(VCANRECYCLE(vp), vp,
  794                     ("vp inconsistent on freelist"));
  795                 freevnodes--;
  796                 vp->v_iflag &= ~VI_FREE;
  797                 vholdl(vp);
  798                 mtx_unlock(&vnode_free_list_mtx);
  799                 VI_UNLOCK(vp);
  800                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  801                 vtryrecycle(vp);
  802                 VFS_UNLOCK_GIANT(vfslocked);
  803                 /*
  804                  * If the recycled succeeded this vdrop will actually free
  805                  * the vnode.  If not it will simply place it back on
  806                  * the free list.
  807                  */
  808                 vdrop(vp);
  809                 mtx_lock(&vnode_free_list_mtx);
  810         }
  811 }
  812 /*
  813  * Attempt to recycle vnodes in a context that is always safe to block.
  814  * Calling vlrurecycle() from the bowels of filesystem code has some
  815  * interesting deadlock problems.
  816  */
  817 static struct proc *vnlruproc;
  818 static int vnlruproc_sig;
  819 
  820 static void
  821 vnlru_proc(void)
  822 {
  823         struct mount *mp, *nmp;
  824         int done, vfslocked;
  825         struct proc *p = vnlruproc;
  826 
  827         EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
  828             SHUTDOWN_PRI_FIRST);
  829 
  830         for (;;) {
  831                 kproc_suspend_check(p);
  832                 mtx_lock(&vnode_free_list_mtx);
  833                 if (freevnodes > wantfreevnodes)
  834                         vnlru_free(freevnodes - wantfreevnodes);
  835                 if (numvnodes <= desiredvnodes * 9 / 10) {
  836                         vnlruproc_sig = 0;
  837                         wakeup(&vnlruproc_sig);
  838                         msleep(vnlruproc, &vnode_free_list_mtx,
  839                             PVFS|PDROP, "vlruwt", hz);
  840                         continue;
  841                 }
  842                 mtx_unlock(&vnode_free_list_mtx);
  843                 done = 0;
  844                 mtx_lock(&mountlist_mtx);
  845                 for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
  846                         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
  847                                 nmp = TAILQ_NEXT(mp, mnt_list);
  848                                 continue;
  849                         }
  850                         vfslocked = VFS_LOCK_GIANT(mp);
  851                         done += vlrureclaim(mp);
  852                         VFS_UNLOCK_GIANT(vfslocked);
  853                         mtx_lock(&mountlist_mtx);
  854                         nmp = TAILQ_NEXT(mp, mnt_list);
  855                         vfs_unbusy(mp);
  856                 }
  857                 mtx_unlock(&mountlist_mtx);
  858                 if (done == 0) {
  859 #if 0
  860                         /* These messages are temporary debugging aids */
  861                         if (vnlru_nowhere < 5)
  862                                 printf("vnlru process getting nowhere..\n");
  863                         else if (vnlru_nowhere == 5)
  864                                 printf("vnlru process messages stopped.\n");
  865 #endif
  866                         vnlru_nowhere++;
  867                         tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
  868                 } else
  869                         uio_yield();
  870         }
  871 }
  872 
  873 static struct kproc_desc vnlru_kp = {
  874         "vnlru",
  875         vnlru_proc,
  876         &vnlruproc
  877 };
  878 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start,
  879     &vnlru_kp);
  880  
  881 /*
  882  * Routines having to do with the management of the vnode table.
  883  */
  884 
  885 void
  886 vdestroy(struct vnode *vp)
  887 {
  888         struct bufobj *bo;
  889 
  890         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  891         mtx_lock(&vnode_free_list_mtx);
  892         numvnodes--;
  893         mtx_unlock(&vnode_free_list_mtx);
  894         bo = &vp->v_bufobj;
  895         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
  896             ("cleaned vnode still on the free list."));
  897         VNASSERT(vp->v_data == NULL, vp, ("cleaned vnode isn't"));
  898         VNASSERT(vp->v_holdcnt == 0, vp, ("Non-zero hold count"));
  899         VNASSERT(vp->v_usecount == 0, vp, ("Non-zero use count"));
  900         VNASSERT(vp->v_writecount == 0, vp, ("Non-zero write count"));
  901         VNASSERT(bo->bo_numoutput == 0, vp, ("Clean vnode has pending I/O's"));
  902         VNASSERT(bo->bo_clean.bv_cnt == 0, vp, ("cleanbufcnt not 0"));
  903         VNASSERT(bo->bo_clean.bv_root == NULL, vp, ("cleanblkroot not NULL"));
  904         VNASSERT(bo->bo_dirty.bv_cnt == 0, vp, ("dirtybufcnt not 0"));
  905         VNASSERT(bo->bo_dirty.bv_root == NULL, vp, ("dirtyblkroot not NULL"));
  906         VNASSERT(TAILQ_EMPTY(&vp->v_cache_dst), vp, ("vp has namecache dst"));
  907         VNASSERT(LIST_EMPTY(&vp->v_cache_src), vp, ("vp has namecache src"));
  908         VNASSERT(vp->v_cache_dd == NULL, vp, ("vp has namecache for .."));
  909         VI_UNLOCK(vp);
  910 #ifdef MAC
  911         mac_vnode_destroy(vp);
  912 #endif
  913         if (vp->v_pollinfo != NULL)
  914                 destroy_vpollinfo(vp->v_pollinfo);
  915 #ifdef INVARIANTS
  916         /* XXX Elsewhere we can detect an already freed vnode via NULL v_op. */
  917         vp->v_op = NULL;
  918 #endif
  919         lockdestroy(vp->v_vnlock);
  920         mtx_destroy(&vp->v_interlock);
  921         mtx_destroy(BO_MTX(bo));
  922         uma_zfree(vnode_zone, vp);
  923 }
  924 
  925 /*
  926  * Try to recycle a freed vnode.  We abort if anyone picks up a reference
  927  * before we actually vgone().  This function must be called with the vnode
  928  * held to prevent the vnode from being returned to the free list midway
  929  * through vgone().
  930  */
  931 static int
  932 vtryrecycle(struct vnode *vp)
  933 {
  934         struct mount *vnmp;
  935 
  936         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
  937         VNASSERT(vp->v_holdcnt, vp,
  938             ("vtryrecycle: Recycling vp %p without a reference.", vp));
  939         /*
  940          * This vnode may found and locked via some other list, if so we
  941          * can't recycle it yet.
  942          */
  943         if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
  944                 CTR2(KTR_VFS,
  945                     "%s: impossible to recycle, vp %p lock is already held",
  946                     __func__, vp);
  947                 return (EWOULDBLOCK);
  948         }
  949         /*
  950          * Don't recycle if its filesystem is being suspended.
  951          */
  952         if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
  953                 VOP_UNLOCK(vp, 0);
  954                 CTR2(KTR_VFS,
  955                     "%s: impossible to recycle, cannot start the write for %p",
  956                     __func__, vp);
  957                 return (EBUSY);
  958         }
  959         /*
  960          * If we got this far, we need to acquire the interlock and see if
  961          * anyone picked up this vnode from another list.  If not, we will
  962          * mark it with DOOMED via vgonel() so that anyone who does find it
  963          * will skip over it.
  964          */
  965         VI_LOCK(vp);
  966         if (vp->v_usecount) {
  967                 VOP_UNLOCK(vp, LK_INTERLOCK);
  968                 vn_finished_write(vnmp);
  969                 CTR2(KTR_VFS,
  970                     "%s: impossible to recycle, %p is already referenced",
  971                     __func__, vp);
  972                 return (EBUSY);
  973         }
  974         if ((vp->v_iflag & VI_DOOMED) == 0)
  975                 vgonel(vp);
  976         VOP_UNLOCK(vp, LK_INTERLOCK);
  977         vn_finished_write(vnmp);
  978         return (0);
  979 }
  980 
  981 /*
  982  * Return the next vnode from the free list.
  983  */
  984 int
  985 getnewvnode(const char *tag, struct mount *mp, struct vop_vector *vops,
  986     struct vnode **vpp)
  987 {
  988         struct vnode *vp = NULL;
  989         struct bufobj *bo;
  990 
  991         CTR3(KTR_VFS, "%s: mp %p with tag %s", __func__, mp, tag);
  992         mtx_lock(&vnode_free_list_mtx);
  993         /*
  994          * Lend our context to reclaim vnodes if they've exceeded the max.
  995          */
  996         if (freevnodes > wantfreevnodes)
  997                 vnlru_free(1);
  998         /*
  999          * Wait for available vnodes.
 1000          */
 1001         if (numvnodes > desiredvnodes) {
 1002                 if (mp != NULL && (mp->mnt_kern_flag & MNTK_SUSPEND)) {
 1003                         /*
 1004                          * File system is beeing suspended, we cannot risk a
 1005                          * deadlock here, so allocate new vnode anyway.
 1006                          */
 1007                         if (freevnodes > wantfreevnodes)
 1008                                 vnlru_free(freevnodes - wantfreevnodes);
 1009                         goto alloc;
 1010                 }
 1011                 if (vnlruproc_sig == 0) {
 1012                         vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
 1013                         wakeup(vnlruproc);
 1014                 }
 1015                 msleep(&vnlruproc_sig, &vnode_free_list_mtx, PVFS,
 1016                     "vlruwk", hz);
 1017 #if 0   /* XXX Not all VFS_VGET/ffs_vget callers check returns. */
 1018                 if (numvnodes > desiredvnodes) {
 1019                         mtx_unlock(&vnode_free_list_mtx);
 1020                         return (ENFILE);
 1021                 }
 1022 #endif
 1023         }
 1024 alloc:
 1025         numvnodes++;
 1026         mtx_unlock(&vnode_free_list_mtx);
 1027         vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
 1028         /*
 1029          * Setup locks.
 1030          */
 1031         vp->v_vnlock = &vp->v_lock;
 1032         mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
 1033         /*
 1034          * By default, don't allow shared locks unless filesystems
 1035          * opt-in.
 1036          */
 1037         lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOSHARE);
 1038         /*
 1039          * Initialize bufobj.
 1040          */
 1041         bo = &vp->v_bufobj;
 1042         bo->__bo_vnode = vp;
 1043         mtx_init(BO_MTX(bo), "bufobj interlock", NULL, MTX_DEF);
 1044         bo->bo_ops = &buf_ops_bio;
 1045         bo->bo_private = vp;
 1046         TAILQ_INIT(&bo->bo_clean.bv_hd);
 1047         TAILQ_INIT(&bo->bo_dirty.bv_hd);
 1048         /*
 1049          * Initialize namecache.
 1050          */
 1051         LIST_INIT(&vp->v_cache_src);
 1052         TAILQ_INIT(&vp->v_cache_dst);
 1053         /*
 1054          * Finalize various vnode identity bits.
 1055          */
 1056         vp->v_type = VNON;
 1057         vp->v_tag = tag;
 1058         vp->v_op = vops;
 1059         v_incr_usecount(vp);
 1060         vp->v_data = 0;
 1061 #ifdef MAC
 1062         mac_vnode_init(vp);
 1063         if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
 1064                 mac_vnode_associate_singlelabel(mp, vp);
 1065         else if (mp == NULL && vops != &dead_vnodeops)
 1066                 printf("NULL mp in getnewvnode()\n");
 1067 #endif
 1068         if (mp != NULL) {
 1069                 bo->bo_bsize = mp->mnt_stat.f_iosize;
 1070                 if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
 1071                         vp->v_vflag |= VV_NOKNOTE;
 1072         }
 1073 
 1074         *vpp = vp;
 1075         return (0);
 1076 }
 1077 
 1078 /*
 1079  * Delete from old mount point vnode list, if on one.
 1080  */
 1081 static void
 1082 delmntque(struct vnode *vp)
 1083 {
 1084         struct mount *mp;
 1085 
 1086         mp = vp->v_mount;
 1087         if (mp == NULL)
 1088                 return;
 1089         MNT_ILOCK(mp);
 1090         vp->v_mount = NULL;
 1091         VNASSERT(mp->mnt_nvnodelistsize > 0, vp,
 1092                 ("bad mount point vnode list size"));
 1093         TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1094         mp->mnt_nvnodelistsize--;
 1095         MNT_REL(mp);
 1096         MNT_IUNLOCK(mp);
 1097 }
 1098 
 1099 static void
 1100 insmntque_stddtr(struct vnode *vp, void *dtr_arg)
 1101 {
 1102 
 1103         vp->v_data = NULL;
 1104         vp->v_op = &dead_vnodeops;
 1105         /* XXX non mp-safe fs may still call insmntque with vnode
 1106            unlocked */
 1107         if (!VOP_ISLOCKED(vp))
 1108                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1109         vgone(vp);
 1110         vput(vp);
 1111 }
 1112 
 1113 /*
 1114  * Insert into list of vnodes for the new mount point, if available.
 1115  */
 1116 int
 1117 insmntque1(struct vnode *vp, struct mount *mp,
 1118         void (*dtr)(struct vnode *, void *), void *dtr_arg)
 1119 {
 1120         int locked;
 1121 
 1122         KASSERT(vp->v_mount == NULL,
 1123                 ("insmntque: vnode already on per mount vnode list"));
 1124         VNASSERT(mp != NULL, vp, ("Don't call insmntque(foo, NULL)"));
 1125 #ifdef DEBUG_VFS_LOCKS
 1126         if (!VFS_NEEDSGIANT(mp))
 1127                 ASSERT_VOP_ELOCKED(vp,
 1128                     "insmntque: mp-safe fs and non-locked vp");
 1129 #endif
 1130         MNT_ILOCK(mp);
 1131         if ((mp->mnt_kern_flag & MNTK_NOINSMNTQ) != 0 &&
 1132             ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0 ||
 1133              mp->mnt_nvnodelistsize == 0)) {
 1134                 locked = VOP_ISLOCKED(vp);
 1135                 if (!locked || (locked == LK_EXCLUSIVE &&
 1136                      (vp->v_vflag & VV_FORCEINSMQ) == 0)) {
 1137                         MNT_IUNLOCK(mp);
 1138                         if (dtr != NULL)
 1139                                 dtr(vp, dtr_arg);
 1140                         return (EBUSY);
 1141                 }
 1142         }
 1143         vp->v_mount = mp;
 1144         MNT_REF(mp);
 1145         TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
 1146         VNASSERT(mp->mnt_nvnodelistsize >= 0, vp,
 1147                 ("neg mount point vnode list size"));
 1148         mp->mnt_nvnodelistsize++;
 1149         MNT_IUNLOCK(mp);
 1150         return (0);
 1151 }
 1152 
 1153 int
 1154 insmntque(struct vnode *vp, struct mount *mp)
 1155 {
 1156 
 1157         return (insmntque1(vp, mp, insmntque_stddtr, NULL));
 1158 }
 1159 
 1160 /*
 1161  * Flush out and invalidate all buffers associated with a bufobj
 1162  * Called with the underlying object locked.
 1163  */
 1164 int
 1165 bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo)
 1166 {
 1167         int error;
 1168 
 1169         BO_LOCK(bo);
 1170         if (flags & V_SAVE) {
 1171                 error = bufobj_wwait(bo, slpflag, slptimeo);
 1172                 if (error) {
 1173                         BO_UNLOCK(bo);
 1174                         return (error);
 1175                 }
 1176                 if (bo->bo_dirty.bv_cnt > 0) {
 1177                         BO_UNLOCK(bo);
 1178                         if ((error = BO_SYNC(bo, MNT_WAIT)) != 0)
 1179                                 return (error);
 1180                         /*
 1181                          * XXX We could save a lock/unlock if this was only
 1182                          * enabled under INVARIANTS
 1183                          */
 1184                         BO_LOCK(bo);
 1185                         if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
 1186                                 panic("vinvalbuf: dirty bufs");
 1187                 }
 1188         }
 1189         /*
 1190          * If you alter this loop please notice that interlock is dropped and
 1191          * reacquired in flushbuflist.  Special care is needed to ensure that
 1192          * no race conditions occur from this.
 1193          */
 1194         do {
 1195                 error = flushbuflist(&bo->bo_clean,
 1196                     flags, bo, slpflag, slptimeo);
 1197                 if (error == 0 && !(flags & V_CLEANONLY))
 1198                         error = flushbuflist(&bo->bo_dirty,
 1199                             flags, bo, slpflag, slptimeo);
 1200                 if (error != 0 && error != EAGAIN) {
 1201                         BO_UNLOCK(bo);
 1202                         return (error);
 1203                 }
 1204         } while (error != 0);
 1205 
 1206         /*
 1207          * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
 1208          * have write I/O in-progress but if there is a VM object then the
 1209          * VM object can also have read-I/O in-progress.
 1210          */
 1211         do {
 1212                 bufobj_wwait(bo, 0, 0);
 1213                 BO_UNLOCK(bo);
 1214                 if (bo->bo_object != NULL) {
 1215                         VM_OBJECT_LOCK(bo->bo_object);
 1216                         vm_object_pip_wait(bo->bo_object, "bovlbx");
 1217                         VM_OBJECT_UNLOCK(bo->bo_object);
 1218                 }
 1219                 BO_LOCK(bo);
 1220         } while (bo->bo_numoutput > 0);
 1221         BO_UNLOCK(bo);
 1222 
 1223         /*
 1224          * Destroy the copy in the VM cache, too.
 1225          */
 1226         if (bo->bo_object != NULL &&
 1227             (flags & (V_ALT | V_NORMAL | V_CLEANONLY)) == 0) {
 1228                 VM_OBJECT_LOCK(bo->bo_object);
 1229                 vm_object_page_remove(bo->bo_object, 0, 0,
 1230                         (flags & V_SAVE) ? TRUE : FALSE);
 1231                 VM_OBJECT_UNLOCK(bo->bo_object);
 1232         }
 1233 
 1234 #ifdef INVARIANTS
 1235         BO_LOCK(bo);
 1236         if ((flags & (V_ALT | V_NORMAL | V_CLEANONLY)) == 0 &&
 1237             (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
 1238                 panic("vinvalbuf: flush failed");
 1239         BO_UNLOCK(bo);
 1240 #endif
 1241         return (0);
 1242 }
 1243 
 1244 /*
 1245  * Flush out and invalidate all buffers associated with a vnode.
 1246  * Called with the underlying object locked.
 1247  */
 1248 int
 1249 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
 1250 {
 1251 
 1252         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 1253         ASSERT_VOP_LOCKED(vp, "vinvalbuf");
 1254         return (bufobj_invalbuf(&vp->v_bufobj, flags, slpflag, slptimeo));
 1255 }
 1256 
 1257 /*
 1258  * Flush out buffers on the specified list.
 1259  *
 1260  */
 1261 static int
 1262 flushbuflist( struct bufv *bufv, int flags, struct bufobj *bo, int slpflag,
 1263     int slptimeo)
 1264 {
 1265         struct buf *bp, *nbp;
 1266         int retval, error;
 1267         daddr_t lblkno;
 1268         b_xflags_t xflags;
 1269 
 1270         ASSERT_BO_LOCKED(bo);
 1271 
 1272         retval = 0;
 1273         TAILQ_FOREACH_SAFE(bp, &bufv->bv_hd, b_bobufs, nbp) {
 1274                 if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
 1275                     ((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
 1276                         continue;
 1277                 }
 1278                 lblkno = 0;
 1279                 xflags = 0;
 1280                 if (nbp != NULL) {
 1281                         lblkno = nbp->b_lblkno;
 1282                         xflags = nbp->b_xflags &
 1283                                 (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN);
 1284                 }
 1285                 retval = EAGAIN;
 1286                 error = BUF_TIMELOCK(bp,
 1287                     LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, BO_MTX(bo),
 1288                     "flushbuf", slpflag, slptimeo);
 1289                 if (error) {
 1290                         BO_LOCK(bo);
 1291                         return (error != ENOLCK ? error : EAGAIN);
 1292                 }
 1293                 KASSERT(bp->b_bufobj == bo,
 1294                     ("bp %p wrong b_bufobj %p should be %p",
 1295                     bp, bp->b_bufobj, bo));
 1296                 if (bp->b_bufobj != bo) {       /* XXX: necessary ? */
 1297                         BUF_UNLOCK(bp);
 1298                         BO_LOCK(bo);
 1299                         return (EAGAIN);
 1300                 }
 1301                 /*
 1302                  * XXX Since there are no node locks for NFS, I
 1303                  * believe there is a slight chance that a delayed
 1304                  * write will occur while sleeping just above, so
 1305                  * check for it.
 1306                  */
 1307                 if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
 1308                     (flags & V_SAVE)) {
 1309                         BO_LOCK(bo);
 1310                         bremfree(bp);
 1311                         BO_UNLOCK(bo);
 1312                         bp->b_flags |= B_ASYNC;
 1313                         bwrite(bp);
 1314                         BO_LOCK(bo);
 1315                         return (EAGAIN);        /* XXX: why not loop ? */
 1316                 }
 1317                 BO_LOCK(bo);
 1318                 bremfree(bp);
 1319                 BO_UNLOCK(bo);
 1320                 bp->b_flags |= (B_INVAL | B_RELBUF);
 1321                 bp->b_flags &= ~B_ASYNC;
 1322                 brelse(bp);
 1323                 BO_LOCK(bo);
 1324                 if (nbp != NULL &&
 1325                     (nbp->b_bufobj != bo ||
 1326                      nbp->b_lblkno != lblkno ||
 1327                      (nbp->b_xflags &
 1328                       (BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN)) != xflags))
 1329                         break;                  /* nbp invalid */
 1330         }
 1331         return (retval);
 1332 }
 1333 
 1334 /*
 1335  * Truncate a file's buffer and pages to a specified length.  This
 1336  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
 1337  * sync activity.
 1338  */
 1339 int
 1340 vtruncbuf(struct vnode *vp, struct ucred *cred, struct thread *td,
 1341     off_t length, int blksize)
 1342 {
 1343         struct buf *bp, *nbp;
 1344         int anyfreed;
 1345         int trunclbn;
 1346         struct bufobj *bo;
 1347 
 1348         CTR5(KTR_VFS, "%s: vp %p with cred %p and block %d:%ju", __func__,
 1349             vp, cred, blksize, (uintmax_t)length);
 1350 
 1351         /*
 1352          * Round up to the *next* lbn.
 1353          */
 1354         trunclbn = (length + blksize - 1) / blksize;
 1355 
 1356         ASSERT_VOP_LOCKED(vp, "vtruncbuf");
 1357 restart:
 1358         bo = &vp->v_bufobj;
 1359         BO_LOCK(bo);
 1360         anyfreed = 1;
 1361         for (;anyfreed;) {
 1362                 anyfreed = 0;
 1363                 TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
 1364                         if (bp->b_lblkno < trunclbn)
 1365                                 continue;
 1366                         if (BUF_LOCK(bp,
 1367                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1368                             BO_MTX(bo)) == ENOLCK)
 1369                                 goto restart;
 1370 
 1371                         BO_LOCK(bo);
 1372                         bremfree(bp);
 1373                         BO_UNLOCK(bo);
 1374                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1375                         bp->b_flags &= ~B_ASYNC;
 1376                         brelse(bp);
 1377                         anyfreed = 1;
 1378 
 1379                         BO_LOCK(bo);
 1380                         if (nbp != NULL &&
 1381                             (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
 1382                             (nbp->b_vp != vp) ||
 1383                             (nbp->b_flags & B_DELWRI))) {
 1384                                 BO_UNLOCK(bo);
 1385                                 goto restart;
 1386                         }
 1387                 }
 1388 
 1389                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1390                         if (bp->b_lblkno < trunclbn)
 1391                                 continue;
 1392                         if (BUF_LOCK(bp,
 1393                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1394                             BO_MTX(bo)) == ENOLCK)
 1395                                 goto restart;
 1396                         BO_LOCK(bo);
 1397                         bremfree(bp);
 1398                         BO_UNLOCK(bo);
 1399                         bp->b_flags |= (B_INVAL | B_RELBUF);
 1400                         bp->b_flags &= ~B_ASYNC;
 1401                         brelse(bp);
 1402                         anyfreed = 1;
 1403 
 1404                         BO_LOCK(bo);
 1405                         if (nbp != NULL &&
 1406                             (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
 1407                             (nbp->b_vp != vp) ||
 1408                             (nbp->b_flags & B_DELWRI) == 0)) {
 1409                                 BO_UNLOCK(bo);
 1410                                 goto restart;
 1411                         }
 1412                 }
 1413         }
 1414 
 1415         if (length > 0) {
 1416 restartsync:
 1417                 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
 1418                         if (bp->b_lblkno > 0)
 1419                                 continue;
 1420                         /*
 1421                          * Since we hold the vnode lock this should only
 1422                          * fail if we're racing with the buf daemon.
 1423                          */
 1424                         if (BUF_LOCK(bp,
 1425                             LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 1426                             BO_MTX(bo)) == ENOLCK) {
 1427                                 goto restart;
 1428                         }
 1429                         VNASSERT((bp->b_flags & B_DELWRI), vp,
 1430                             ("buf(%p) on dirty queue without DELWRI", bp));
 1431 
 1432                         BO_LOCK(bo);
 1433                         bremfree(bp);
 1434                         BO_UNLOCK(bo);
 1435                         bawrite(bp);
 1436                         BO_LOCK(bo);
 1437                         goto restartsync;
 1438                 }
 1439         }
 1440 
 1441         bufobj_wwait(bo, 0, 0);
 1442         BO_UNLOCK(bo);
 1443         vnode_pager_setsize(vp, length);
 1444 
 1445         return (0);
 1446 }
 1447 
 1448 /*
 1449  * buf_splay() - splay tree core for the clean/dirty list of buffers in
 1450  *               a vnode.
 1451  *
 1452  *      NOTE: We have to deal with the special case of a background bitmap
 1453  *      buffer, a situation where two buffers will have the same logical
 1454  *      block offset.  We want (1) only the foreground buffer to be accessed
 1455  *      in a lookup and (2) must differentiate between the foreground and
 1456  *      background buffer in the splay tree algorithm because the splay
 1457  *      tree cannot normally handle multiple entities with the same 'index'.
 1458  *      We accomplish this by adding differentiating flags to the splay tree's
 1459  *      numerical domain.
 1460  */
 1461 static
 1462 struct buf *
 1463 buf_splay(daddr_t lblkno, b_xflags_t xflags, struct buf *root)
 1464 {
 1465         struct buf dummy;
 1466         struct buf *lefttreemax, *righttreemin, *y;
 1467 
 1468         if (root == NULL)
 1469                 return (NULL);
 1470         lefttreemax = righttreemin = &dummy;
 1471         for (;;) {
 1472                 if (lblkno < root->b_lblkno ||
 1473                     (lblkno == root->b_lblkno &&
 1474                     (xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1475                         if ((y = root->b_left) == NULL)
 1476                                 break;
 1477                         if (lblkno < y->b_lblkno) {
 1478                                 /* Rotate right. */
 1479                                 root->b_left = y->b_right;
 1480                                 y->b_right = root;
 1481                                 root = y;
 1482                                 if ((y = root->b_left) == NULL)
 1483                                         break;
 1484                         }
 1485                         /* Link into the new root's right tree. */
 1486                         righttreemin->b_left = root;
 1487                         righttreemin = root;
 1488                 } else if (lblkno > root->b_lblkno ||
 1489                     (lblkno == root->b_lblkno &&
 1490                     (xflags & BX_BKGRDMARKER) > (root->b_xflags & BX_BKGRDMARKER))) {
 1491                         if ((y = root->b_right) == NULL)
 1492                                 break;
 1493                         if (lblkno > y->b_lblkno) {
 1494                                 /* Rotate left. */
 1495                                 root->b_right = y->b_left;
 1496                                 y->b_left = root;
 1497                                 root = y;
 1498                                 if ((y = root->b_right) == NULL)
 1499                                         break;
 1500                         }
 1501                         /* Link into the new root's left tree. */
 1502                         lefttreemax->b_right = root;
 1503                         lefttreemax = root;
 1504                 } else {
 1505                         break;
 1506                 }
 1507                 root = y;
 1508         }
 1509         /* Assemble the new root. */
 1510         lefttreemax->b_right = root->b_left;
 1511         righttreemin->b_left = root->b_right;
 1512         root->b_left = dummy.b_right;
 1513         root->b_right = dummy.b_left;
 1514         return (root);
 1515 }
 1516 
 1517 static void
 1518 buf_vlist_remove(struct buf *bp)
 1519 {
 1520         struct buf *root;
 1521         struct bufv *bv;
 1522 
 1523         KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
 1524         ASSERT_BO_LOCKED(bp->b_bufobj);
 1525         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) !=
 1526             (BX_VNDIRTY|BX_VNCLEAN),
 1527             ("buf_vlist_remove: Buf %p is on two lists", bp));
 1528         if (bp->b_xflags & BX_VNDIRTY)
 1529                 bv = &bp->b_bufobj->bo_dirty;
 1530         else
 1531                 bv = &bp->b_bufobj->bo_clean;
 1532         if (bp != bv->bv_root) {
 1533                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1534                 KASSERT(root == bp, ("splay lookup failed in remove"));
 1535         }
 1536         if (bp->b_left == NULL) {
 1537                 root = bp->b_right;
 1538         } else {
 1539                 root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
 1540                 root->b_right = bp->b_right;
 1541         }
 1542         bv->bv_root = root;
 1543         TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
 1544         bv->bv_cnt--;
 1545         bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
 1546 }
 1547 
 1548 /*
 1549  * Add the buffer to the sorted clean or dirty block list using a
 1550  * splay tree algorithm.
 1551  *
 1552  * NOTE: xflags is passed as a constant, optimizing this inline function!
 1553  */
 1554 static void
 1555 buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
 1556 {
 1557         struct buf *root;
 1558         struct bufv *bv;
 1559 
 1560         ASSERT_BO_LOCKED(bo);
 1561         KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
 1562             ("buf_vlist_add: Buf %p has existing xflags %d", bp, bp->b_xflags));
 1563         bp->b_xflags |= xflags;
 1564         if (xflags & BX_VNDIRTY)
 1565                 bv = &bo->bo_dirty;
 1566         else
 1567                 bv = &bo->bo_clean;
 1568 
 1569         root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
 1570         if (root == NULL) {
 1571                 bp->b_left = NULL;
 1572                 bp->b_right = NULL;
 1573                 TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
 1574         } else if (bp->b_lblkno < root->b_lblkno ||
 1575             (bp->b_lblkno == root->b_lblkno &&
 1576             (bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
 1577                 bp->b_left = root->b_left;
 1578                 bp->b_right = root;
 1579                 root->b_left = NULL;
 1580                 TAILQ_INSERT_BEFORE(root, bp, b_bobufs);
 1581         } else {
 1582                 bp->b_right = root->b_right;
 1583                 bp->b_left = root;
 1584                 root->b_right = NULL;
 1585                 TAILQ_INSERT_AFTER(&bv->bv_hd, root, bp, b_bobufs);
 1586         }
 1587         bv->bv_cnt++;
 1588         bv->bv_root = bp;
 1589 }
 1590 
 1591 /*
 1592  * Lookup a buffer using the splay tree.  Note that we specifically avoid
 1593  * shadow buffers used in background bitmap writes.
 1594  *
 1595  * This code isn't quite efficient as it could be because we are maintaining
 1596  * two sorted lists and do not know which list the block resides in.
 1597  *
 1598  * During a "make buildworld" the desired buffer is found at one of
 1599  * the roots more than 60% of the time.  Thus, checking both roots
 1600  * before performing either splay eliminates unnecessary splays on the
 1601  * first tree splayed.
 1602  */
 1603 struct buf *
 1604 gbincore(struct bufobj *bo, daddr_t lblkno)
 1605 {
 1606         struct buf *bp;
 1607 
 1608         ASSERT_BO_LOCKED(bo);
 1609         if ((bp = bo->bo_clean.bv_root) != NULL &&
 1610             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1611                 return (bp);
 1612         if ((bp = bo->bo_dirty.bv_root) != NULL &&
 1613             bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1614                 return (bp);
 1615         if ((bp = bo->bo_clean.bv_root) != NULL) {
 1616                 bo->bo_clean.bv_root = bp = buf_splay(lblkno, 0, bp);
 1617                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1618                         return (bp);
 1619         }
 1620         if ((bp = bo->bo_dirty.bv_root) != NULL) {
 1621                 bo->bo_dirty.bv_root = bp = buf_splay(lblkno, 0, bp);
 1622                 if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
 1623                         return (bp);
 1624         }
 1625         return (NULL);
 1626 }
 1627 
 1628 /*
 1629  * Associate a buffer with a vnode.
 1630  */
 1631 void
 1632 bgetvp(struct vnode *vp, struct buf *bp)
 1633 {
 1634         struct bufobj *bo;
 1635 
 1636         bo = &vp->v_bufobj;
 1637         ASSERT_BO_LOCKED(bo);
 1638         VNASSERT(bp->b_vp == NULL, bp->b_vp, ("bgetvp: not free"));
 1639 
 1640         CTR3(KTR_BUF, "bgetvp(%p) vp %p flags %X", bp, vp, bp->b_flags);
 1641         VNASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0, vp,
 1642             ("bgetvp: bp already attached! %p", bp));
 1643 
 1644         vhold(vp);
 1645         if (VFS_NEEDSGIANT(vp->v_mount) || bo->bo_flag & BO_NEEDSGIANT)
 1646                 bp->b_flags |= B_NEEDSGIANT;
 1647         bp->b_vp = vp;
 1648         bp->b_bufobj = bo;
 1649         /*
 1650          * Insert onto list for new vnode.
 1651          */
 1652         buf_vlist_add(bp, bo, BX_VNCLEAN);
 1653 }
 1654 
 1655 /*
 1656  * Disassociate a buffer from a vnode.
 1657  */
 1658 void
 1659 brelvp(struct buf *bp)
 1660 {
 1661         struct bufobj *bo;
 1662         struct vnode *vp;
 1663 
 1664         CTR3(KTR_BUF, "brelvp(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
 1665         KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
 1666 
 1667         /*
 1668          * Delete from old vnode list, if on one.
 1669          */
 1670         vp = bp->b_vp;          /* XXX */
 1671         bo = bp->b_bufobj;
 1672         BO_LOCK(bo);
 1673         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 1674                 buf_vlist_remove(bp);
 1675         else
 1676                 panic("brelvp: Buffer %p not on queue.", bp);
 1677         if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 1678                 bo->bo_flag &= ~BO_ONWORKLST;
 1679                 mtx_lock(&sync_mtx);
 1680                 LIST_REMOVE(bo, bo_synclist);
 1681                 syncer_worklist_len--;
 1682                 mtx_unlock(&sync_mtx);
 1683         }
 1684         bp->b_flags &= ~B_NEEDSGIANT;
 1685         bp->b_vp = NULL;
 1686         bp->b_bufobj = NULL;
 1687         BO_UNLOCK(bo);
 1688         vdrop(vp);
 1689 }
 1690 
 1691 /*
 1692  * Add an item to the syncer work queue.
 1693  */
 1694 static void
 1695 vn_syncer_add_to_worklist(struct bufobj *bo, int delay)
 1696 {
 1697         int queue, slot;
 1698 
 1699         ASSERT_BO_LOCKED(bo);
 1700 
 1701         mtx_lock(&sync_mtx);
 1702         if (bo->bo_flag & BO_ONWORKLST)
 1703                 LIST_REMOVE(bo, bo_synclist);
 1704         else {
 1705                 bo->bo_flag |= BO_ONWORKLST;
 1706                 syncer_worklist_len++;
 1707         }
 1708 
 1709         if (delay > syncer_maxdelay - 2)
 1710                 delay = syncer_maxdelay - 2;
 1711         slot = (syncer_delayno + delay) & syncer_mask;
 1712 
 1713         queue = VFS_NEEDSGIANT(bo->__bo_vnode->v_mount) ? WI_GIANTQ :
 1714             WI_MPSAFEQ;
 1715         LIST_INSERT_HEAD(&syncer_workitem_pending[queue][slot], bo,
 1716             bo_synclist);
 1717         mtx_unlock(&sync_mtx);
 1718 }
 1719 
 1720 static int
 1721 sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
 1722 {
 1723         int error, len;
 1724 
 1725         mtx_lock(&sync_mtx);
 1726         len = syncer_worklist_len - sync_vnode_count;
 1727         mtx_unlock(&sync_mtx);
 1728         error = SYSCTL_OUT(req, &len, sizeof(len));
 1729         return (error);
 1730 }
 1731 
 1732 SYSCTL_PROC(_vfs, OID_AUTO, worklist_len, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
 1733     sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
 1734 
 1735 static struct proc *updateproc;
 1736 static void sched_sync(void);
 1737 static struct kproc_desc up_kp = {
 1738         "syncer",
 1739         sched_sync,
 1740         &updateproc
 1741 };
 1742 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp);
 1743 
 1744 static int
 1745 sync_vnode(struct synclist *slp, struct bufobj **bo, struct thread *td)
 1746 {
 1747         struct vnode *vp;
 1748         struct mount *mp;
 1749 
 1750         *bo = LIST_FIRST(slp);
 1751         if (*bo == NULL)
 1752                 return (0);
 1753         vp = (*bo)->__bo_vnode; /* XXX */
 1754         if (VOP_ISLOCKED(vp) != 0 || VI_TRYLOCK(vp) == 0)
 1755                 return (1);
 1756         /*
 1757          * We use vhold in case the vnode does not
 1758          * successfully sync.  vhold prevents the vnode from
 1759          * going away when we unlock the sync_mtx so that
 1760          * we can acquire the vnode interlock.
 1761          */
 1762         vholdl(vp);
 1763         mtx_unlock(&sync_mtx);
 1764         VI_UNLOCK(vp);
 1765         if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
 1766                 vdrop(vp);
 1767                 mtx_lock(&sync_mtx);
 1768                 return (*bo == LIST_FIRST(slp));
 1769         }
 1770         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1771         (void) VOP_FSYNC(vp, MNT_LAZY, td);
 1772         VOP_UNLOCK(vp, 0);
 1773         vn_finished_write(mp);
 1774         BO_LOCK(*bo);
 1775         if (((*bo)->bo_flag & BO_ONWORKLST) != 0) {
 1776                 /*
 1777                  * Put us back on the worklist.  The worklist
 1778                  * routine will remove us from our current
 1779                  * position and then add us back in at a later
 1780                  * position.
 1781                  */
 1782                 vn_syncer_add_to_worklist(*bo, syncdelay);
 1783         }
 1784         BO_UNLOCK(*bo);
 1785         vdrop(vp);
 1786         mtx_lock(&sync_mtx);
 1787         return (0);
 1788 }
 1789 
 1790 /*
 1791  * System filesystem synchronizer daemon.
 1792  */
 1793 static void
 1794 sched_sync(void)
 1795 {
 1796         struct synclist *gnext, *next;
 1797         struct synclist *gslp, *slp;
 1798         struct bufobj *bo;
 1799         long starttime;
 1800         struct thread *td = curthread;
 1801         int last_work_seen;
 1802         int net_worklist_len;
 1803         int syncer_final_iter;
 1804         int first_printf;
 1805         int error;
 1806 
 1807         last_work_seen = 0;
 1808         syncer_final_iter = 0;
 1809         first_printf = 1;
 1810         syncer_state = SYNCER_RUNNING;
 1811         starttime = time_uptime;
 1812         td->td_pflags |= TDP_NORUNNINGBUF;
 1813 
 1814         EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
 1815             SHUTDOWN_PRI_LAST);
 1816 
 1817         mtx_lock(&sync_mtx);
 1818         for (;;) {
 1819                 if (syncer_state == SYNCER_FINAL_DELAY &&
 1820                     syncer_final_iter == 0) {
 1821                         mtx_unlock(&sync_mtx);
 1822                         kproc_suspend_check(td->td_proc);
 1823                         mtx_lock(&sync_mtx);
 1824                 }
 1825                 net_worklist_len = syncer_worklist_len - sync_vnode_count;
 1826                 if (syncer_state != SYNCER_RUNNING &&
 1827                     starttime != time_uptime) {
 1828                         if (first_printf) {
 1829                                 printf("\nSyncing disks, vnodes remaining...");
 1830                                 first_printf = 0;
 1831                         }
 1832                         printf("%d ", net_worklist_len);
 1833                 }
 1834                 starttime = time_uptime;
 1835 
 1836                 /*
 1837                  * Push files whose dirty time has expired.  Be careful
 1838                  * of interrupt race on slp queue.
 1839                  *
 1840                  * Skip over empty worklist slots when shutting down.
 1841                  */
 1842                 do {
 1843                         slp = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1844                         gslp = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1845                         syncer_delayno += 1;
 1846                         if (syncer_delayno == syncer_maxdelay)
 1847                                 syncer_delayno = 0;
 1848                         next = &syncer_workitem_pending[WI_MPSAFEQ][syncer_delayno];
 1849                         gnext = &syncer_workitem_pending[WI_GIANTQ][syncer_delayno];
 1850                         /*
 1851                          * If the worklist has wrapped since the
 1852                          * it was emptied of all but syncer vnodes,
 1853                          * switch to the FINAL_DELAY state and run
 1854                          * for one more second.
 1855                          */
 1856                         if (syncer_state == SYNCER_SHUTTING_DOWN &&
 1857                             net_worklist_len == 0 &&
 1858                             last_work_seen == syncer_delayno) {
 1859                                 syncer_state = SYNCER_FINAL_DELAY;
 1860                                 syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
 1861                         }
 1862                 } while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
 1863                     LIST_EMPTY(gslp) && syncer_worklist_len > 0);
 1864 
 1865                 /*
 1866                  * Keep track of the last time there was anything
 1867                  * on the worklist other than syncer vnodes.
 1868                  * Return to the SHUTTING_DOWN state if any
 1869                  * new work appears.
 1870                  */
 1871                 if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
 1872                         last_work_seen = syncer_delayno;
 1873                 if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
 1874                         syncer_state = SYNCER_SHUTTING_DOWN;
 1875                 while (!LIST_EMPTY(slp)) {
 1876                         error = sync_vnode(slp, &bo, td);
 1877                         if (error == 1) {
 1878                                 LIST_REMOVE(bo, bo_synclist);
 1879                                 LIST_INSERT_HEAD(next, bo, bo_synclist);
 1880                                 continue;
 1881                         }
 1882 #ifdef SW_WATCHDOG
 1883                         if (first_printf == 0)
 1884                                 wdog_kern_pat(WD_LASTVAL);
 1885 #endif
 1886                 }
 1887                 if (!LIST_EMPTY(gslp)) {
 1888                         mtx_unlock(&sync_mtx);
 1889                         mtx_lock(&Giant);
 1890                         mtx_lock(&sync_mtx);
 1891                         while (!LIST_EMPTY(gslp)) {
 1892                                 error = sync_vnode(gslp, &bo, td);
 1893                                 if (error == 1) {
 1894                                         LIST_REMOVE(bo, bo_synclist);
 1895                                         LIST_INSERT_HEAD(gnext, bo,
 1896                                             bo_synclist);
 1897                                         continue;
 1898                                 }
 1899                         }
 1900                         mtx_unlock(&Giant);
 1901                 }
 1902                 if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
 1903                         syncer_final_iter--;
 1904                 /*
 1905                  * The variable rushjob allows the kernel to speed up the
 1906                  * processing of the filesystem syncer process. A rushjob
 1907                  * value of N tells the filesystem syncer to process the next
 1908                  * N seconds worth of work on its queue ASAP. Currently rushjob
 1909                  * is used by the soft update code to speed up the filesystem
 1910                  * syncer process when the incore state is getting so far
 1911                  * ahead of the disk that the kernel memory pool is being
 1912                  * threatened with exhaustion.
 1913                  */
 1914                 if (rushjob > 0) {
 1915                         rushjob -= 1;
 1916                         continue;
 1917                 }
 1918                 /*
 1919                  * Just sleep for a short period of time between
 1920                  * iterations when shutting down to allow some I/O
 1921                  * to happen.
 1922                  *
 1923                  * If it has taken us less than a second to process the
 1924                  * current work, then wait. Otherwise start right over
 1925                  * again. We can still lose time if any single round
 1926                  * takes more than two seconds, but it does not really
 1927                  * matter as we are just trying to generally pace the
 1928                  * filesystem activity.
 1929                  */
 1930                 if (syncer_state != SYNCER_RUNNING ||
 1931                     time_uptime == starttime) {
 1932                         thread_lock(td);
 1933                         sched_prio(td, PPAUSE);
 1934                         thread_unlock(td);
 1935                 }
 1936                 if (syncer_state != SYNCER_RUNNING)
 1937                         cv_timedwait(&sync_wakeup, &sync_mtx,
 1938                             hz / SYNCER_SHUTDOWN_SPEEDUP);
 1939                 else if (time_uptime == starttime)
 1940                         cv_timedwait(&sync_wakeup, &sync_mtx, hz);
 1941         }
 1942 }
 1943 
 1944 /*
 1945  * Request the syncer daemon to speed up its work.
 1946  * We never push it to speed up more than half of its
 1947  * normal turn time, otherwise it could take over the cpu.
 1948  */
 1949 int
 1950 speedup_syncer(void)
 1951 {
 1952         int ret = 0;
 1953 
 1954         mtx_lock(&sync_mtx);
 1955         if (rushjob < syncdelay / 2) {
 1956                 rushjob += 1;
 1957                 stat_rush_requests += 1;
 1958                 ret = 1;
 1959         }
 1960         mtx_unlock(&sync_mtx);
 1961         cv_broadcast(&sync_wakeup);
 1962         return (ret);
 1963 }
 1964 
 1965 /*
 1966  * Tell the syncer to speed up its work and run though its work
 1967  * list several times, then tell it to shut down.
 1968  */
 1969 static void
 1970 syncer_shutdown(void *arg, int howto)
 1971 {
 1972 
 1973         if (howto & RB_NOSYNC)
 1974                 return;
 1975         mtx_lock(&sync_mtx);
 1976         syncer_state = SYNCER_SHUTTING_DOWN;
 1977         rushjob = 0;
 1978         mtx_unlock(&sync_mtx);
 1979         cv_broadcast(&sync_wakeup);
 1980         kproc_shutdown(arg, howto);
 1981 }
 1982 
 1983 /*
 1984  * Reassign a buffer from one vnode to another.
 1985  * Used to assign file specific control information
 1986  * (indirect blocks) to the vnode to which they belong.
 1987  */
 1988 void
 1989 reassignbuf(struct buf *bp)
 1990 {
 1991         struct vnode *vp;
 1992         struct bufobj *bo;
 1993         int delay;
 1994 #ifdef INVARIANTS
 1995         struct bufv *bv;
 1996 #endif
 1997 
 1998         vp = bp->b_vp;
 1999         bo = bp->b_bufobj;
 2000         ++reassignbufcalls;
 2001 
 2002         CTR3(KTR_BUF, "reassignbuf(%p) vp %p flags %X",
 2003             bp, bp->b_vp, bp->b_flags);
 2004         /*
 2005          * B_PAGING flagged buffers cannot be reassigned because their vp
 2006          * is not fully linked in.
 2007          */
 2008         if (bp->b_flags & B_PAGING)
 2009                 panic("cannot reassign paging buffer");
 2010 
 2011         /*
 2012          * Delete from old vnode list, if on one.
 2013          */
 2014         BO_LOCK(bo);
 2015         if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
 2016                 buf_vlist_remove(bp);
 2017         else
 2018                 panic("reassignbuf: Buffer %p not on queue.", bp);
 2019         /*
 2020          * If dirty, put on list of dirty buffers; otherwise insert onto list
 2021          * of clean buffers.
 2022          */
 2023         if (bp->b_flags & B_DELWRI) {
 2024                 if ((bo->bo_flag & BO_ONWORKLST) == 0) {
 2025                         switch (vp->v_type) {
 2026                         case VDIR:
 2027                                 delay = dirdelay;
 2028                                 break;
 2029                         case VCHR:
 2030                                 delay = metadelay;
 2031                                 break;
 2032                         default:
 2033                                 delay = filedelay;
 2034                         }
 2035                         vn_syncer_add_to_worklist(bo, delay);
 2036                 }
 2037                 buf_vlist_add(bp, bo, BX_VNDIRTY);
 2038         } else {
 2039                 buf_vlist_add(bp, bo, BX_VNCLEAN);
 2040 
 2041                 if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
 2042                         mtx_lock(&sync_mtx);
 2043                         LIST_REMOVE(bo, bo_synclist);
 2044                         syncer_worklist_len--;
 2045                         mtx_unlock(&sync_mtx);
 2046                         bo->bo_flag &= ~BO_ONWORKLST;
 2047                 }
 2048         }
 2049 #ifdef INVARIANTS
 2050         bv = &bo->bo_clean;
 2051         bp = TAILQ_FIRST(&bv->bv_hd);
 2052         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2053             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2054         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 2055         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2056             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2057         bv = &bo->bo_dirty;
 2058         bp = TAILQ_FIRST(&bv->bv_hd);
 2059         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2060             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2061         bp = TAILQ_LAST(&bv->bv_hd, buflists);
 2062         KASSERT(bp == NULL || bp->b_bufobj == bo,
 2063             ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
 2064 #endif
 2065         BO_UNLOCK(bo);
 2066 }
 2067 
 2068 /*
 2069  * Increment the use and hold counts on the vnode, taking care to reference
 2070  * the driver's usecount if this is a chardev.  The vholdl() will remove
 2071  * the vnode from the free list if it is presently free.  Requires the
 2072  * vnode interlock and returns with it held.
 2073  */
 2074 static void
 2075 v_incr_usecount(struct vnode *vp)
 2076 {
 2077 
 2078         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2079         vp->v_usecount++;
 2080         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2081                 dev_lock();
 2082                 vp->v_rdev->si_usecount++;
 2083                 dev_unlock();
 2084         }
 2085         vholdl(vp);
 2086 }
 2087 
 2088 /*
 2089  * Turn a holdcnt into a use+holdcnt such that only one call to
 2090  * v_decr_usecount is needed.
 2091  */
 2092 static void
 2093 v_upgrade_usecount(struct vnode *vp)
 2094 {
 2095 
 2096         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2097         vp->v_usecount++;
 2098         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2099                 dev_lock();
 2100                 vp->v_rdev->si_usecount++;
 2101                 dev_unlock();
 2102         }
 2103 }
 2104 
 2105 /*
 2106  * Decrement the vnode use and hold count along with the driver's usecount
 2107  * if this is a chardev.  The vdropl() below releases the vnode interlock
 2108  * as it may free the vnode.
 2109  */
 2110 static void
 2111 v_decr_usecount(struct vnode *vp)
 2112 {
 2113 
 2114         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2115         VNASSERT(vp->v_usecount > 0, vp,
 2116             ("v_decr_usecount: negative usecount"));
 2117         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2118         vp->v_usecount--;
 2119         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2120                 dev_lock();
 2121                 vp->v_rdev->si_usecount--;
 2122                 dev_unlock();
 2123         }
 2124         vdropl(vp);
 2125 }
 2126 
 2127 /*
 2128  * Decrement only the use count and driver use count.  This is intended to
 2129  * be paired with a follow on vdropl() to release the remaining hold count.
 2130  * In this way we may vgone() a vnode with a 0 usecount without risk of
 2131  * having it end up on a free list because the hold count is kept above 0.
 2132  */
 2133 static void
 2134 v_decr_useonly(struct vnode *vp)
 2135 {
 2136 
 2137         ASSERT_VI_LOCKED(vp, __FUNCTION__);
 2138         VNASSERT(vp->v_usecount > 0, vp,
 2139             ("v_decr_useonly: negative usecount"));
 2140         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2141         vp->v_usecount--;
 2142         if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 2143                 dev_lock();
 2144                 vp->v_rdev->si_usecount--;
 2145                 dev_unlock();
 2146         }
 2147 }
 2148 
 2149 /*
 2150  * Grab a particular vnode from the free list, increment its
 2151  * reference count and lock it.  VI_DOOMED is set if the vnode
 2152  * is being destroyed.  Only callers who specify LK_RETRY will
 2153  * see doomed vnodes.  If inactive processing was delayed in
 2154  * vput try to do it here.
 2155  */
 2156 int
 2157 vget(struct vnode *vp, int flags, struct thread *td)
 2158 {
 2159         int error;
 2160 
 2161         error = 0;
 2162         VFS_ASSERT_GIANT(vp->v_mount);
 2163         VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
 2164             ("vget: invalid lock operation"));
 2165         CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
 2166 
 2167         if ((flags & LK_INTERLOCK) == 0)
 2168                 VI_LOCK(vp);
 2169         vholdl(vp);
 2170         if ((error = vn_lock(vp, flags | LK_INTERLOCK)) != 0) {
 2171                 vdrop(vp);
 2172                 CTR2(KTR_VFS, "%s: impossible to lock vnode %p", __func__,
 2173                     vp);
 2174                 return (error);
 2175         }
 2176         if (vp->v_iflag & VI_DOOMED && (flags & LK_RETRY) == 0)
 2177                 panic("vget: vn_lock failed to return ENOENT\n");
 2178         VI_LOCK(vp);
 2179         /* Upgrade our holdcnt to a usecount. */
 2180         v_upgrade_usecount(vp);
 2181         /*
 2182          * We don't guarantee that any particular close will
 2183          * trigger inactive processing so just make a best effort
 2184          * here at preventing a reference to a removed file.  If
 2185          * we don't succeed no harm is done.
 2186          */
 2187         if (vp->v_iflag & VI_OWEINACT) {
 2188                 if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE && 
 2189                     (flags & LK_NOWAIT) == 0)
 2190                         vinactive(vp, td);
 2191                 vp->v_iflag &= ~VI_OWEINACT;
 2192         }
 2193         VI_UNLOCK(vp);
 2194         return (0);
 2195 }
 2196 
 2197 /*
 2198  * Increase the reference count of a vnode.
 2199  */
 2200 void
 2201 vref(struct vnode *vp)
 2202 {
 2203 
 2204         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2205         VI_LOCK(vp);
 2206         v_incr_usecount(vp);
 2207         VI_UNLOCK(vp);
 2208 }
 2209 
 2210 /*
 2211  * Return reference count of a vnode.
 2212  *
 2213  * The results of this call are only guaranteed when some mechanism other
 2214  * than the VI lock is used to stop other processes from gaining references
 2215  * to the vnode.  This may be the case if the caller holds the only reference.
 2216  * This is also useful when stale data is acceptable as race conditions may
 2217  * be accounted for by some other means.
 2218  */
 2219 int
 2220 vrefcnt(struct vnode *vp)
 2221 {
 2222         int usecnt;
 2223 
 2224         VI_LOCK(vp);
 2225         usecnt = vp->v_usecount;
 2226         VI_UNLOCK(vp);
 2227 
 2228         return (usecnt);
 2229 }
 2230 
 2231 #define VPUTX_VRELE     1
 2232 #define VPUTX_VPUT      2
 2233 #define VPUTX_VUNREF    3
 2234 
 2235 static void
 2236 vputx(struct vnode *vp, int func)
 2237 {
 2238         int error;
 2239 
 2240         KASSERT(vp != NULL, ("vputx: null vp"));
 2241         if (func == VPUTX_VUNREF)
 2242                 ASSERT_VOP_LOCKED(vp, "vunref");
 2243         else if (func == VPUTX_VPUT)
 2244                 ASSERT_VOP_LOCKED(vp, "vput");
 2245         else
 2246                 KASSERT(func == VPUTX_VRELE, ("vputx: wrong func"));
 2247         VFS_ASSERT_GIANT(vp->v_mount);
 2248         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2249         VI_LOCK(vp);
 2250 
 2251         /* Skip this v_writecount check if we're going to panic below. */
 2252         VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
 2253             ("vputx: missed vn_close"));
 2254         error = 0;
 2255 
 2256         if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
 2257             vp->v_usecount == 1)) {
 2258                 if (func == VPUTX_VPUT)
 2259                         VOP_UNLOCK(vp, 0);
 2260                 v_decr_usecount(vp);
 2261                 return;
 2262         }
 2263 
 2264         if (vp->v_usecount != 1) {
 2265                 vprint("vputx: negative ref count", vp);
 2266                 panic("vputx: negative ref cnt");
 2267         }
 2268         CTR2(KTR_VFS, "%s: return vnode %p to the freelist", __func__, vp);
 2269         /*
 2270          * We want to hold the vnode until the inactive finishes to
 2271          * prevent vgone() races.  We drop the use count here and the
 2272          * hold count below when we're done.
 2273          */
 2274         v_decr_useonly(vp);
 2275         /*
 2276          * We must call VOP_INACTIVE with the node locked. Mark
 2277          * as VI_DOINGINACT to avoid recursion.
 2278          */
 2279         vp->v_iflag |= VI_OWEINACT;
 2280         switch (func) {
 2281         case VPUTX_VRELE:
 2282                 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK);
 2283                 VI_LOCK(vp);
 2284                 break;
 2285         case VPUTX_VPUT:
 2286                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
 2287                         error = VOP_LOCK(vp, LK_UPGRADE | LK_INTERLOCK |
 2288                             LK_NOWAIT);
 2289                         VI_LOCK(vp);
 2290                 }
 2291                 break;
 2292         case VPUTX_VUNREF:
 2293                 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 2294                         error = EBUSY;
 2295                 break;
 2296         }
 2297         if (vp->v_usecount > 0)
 2298                 vp->v_iflag &= ~VI_OWEINACT;
 2299         if (error == 0) {
 2300                 if (vp->v_iflag & VI_OWEINACT)
 2301                         vinactive(vp, curthread);
 2302                 if (func != VPUTX_VUNREF)
 2303                         VOP_UNLOCK(vp, 0);
 2304         }
 2305         vdropl(vp);
 2306 }
 2307 
 2308 /*
 2309  * Vnode put/release.
 2310  * If count drops to zero, call inactive routine and return to freelist.
 2311  */
 2312 void
 2313 vrele(struct vnode *vp)
 2314 {
 2315 
 2316         vputx(vp, VPUTX_VRELE);
 2317 }
 2318 
 2319 /*
 2320  * Release an already locked vnode.  This give the same effects as
 2321  * unlock+vrele(), but takes less time and avoids releasing and
 2322  * re-aquiring the lock (as vrele() acquires the lock internally.)
 2323  */
 2324 void
 2325 vput(struct vnode *vp)
 2326 {
 2327 
 2328         vputx(vp, VPUTX_VPUT);
 2329 }
 2330 
 2331 /*
 2332  * Release an exclusively locked vnode. Do not unlock the vnode lock.
 2333  */
 2334 void
 2335 vunref(struct vnode *vp)
 2336 {
 2337 
 2338         vputx(vp, VPUTX_VUNREF);
 2339 }
 2340 
 2341 /*
 2342  * Somebody doesn't want the vnode recycled.
 2343  */
 2344 void
 2345 vhold(struct vnode *vp)
 2346 {
 2347 
 2348         VI_LOCK(vp);
 2349         vholdl(vp);
 2350         VI_UNLOCK(vp);
 2351 }
 2352 
 2353 void
 2354 vholdl(struct vnode *vp)
 2355 {
 2356 
 2357         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2358         vp->v_holdcnt++;
 2359         if (VSHOULDBUSY(vp))
 2360                 vbusy(vp);
 2361 }
 2362 
 2363 /*
 2364  * Note that there is one less who cares about this vnode.  vdrop() is the
 2365  * opposite of vhold().
 2366  */
 2367 void
 2368 vdrop(struct vnode *vp)
 2369 {
 2370 
 2371         VI_LOCK(vp);
 2372         vdropl(vp);
 2373 }
 2374 
 2375 /*
 2376  * Drop the hold count of the vnode.  If this is the last reference to
 2377  * the vnode we will free it if it has been vgone'd otherwise it is
 2378  * placed on the free list.
 2379  */
 2380 void
 2381 vdropl(struct vnode *vp)
 2382 {
 2383 
 2384         ASSERT_VI_LOCKED(vp, "vdropl");
 2385         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2386         if (vp->v_holdcnt <= 0)
 2387                 panic("vdrop: holdcnt %d", vp->v_holdcnt);
 2388         vp->v_holdcnt--;
 2389         if (vp->v_holdcnt == 0) {
 2390                 if (vp->v_iflag & VI_DOOMED) {
 2391                         CTR2(KTR_VFS, "%s: destroying the vnode %p", __func__,
 2392                             vp);
 2393                         vdestroy(vp);
 2394                         return;
 2395                 } else
 2396                         vfree(vp);
 2397         }
 2398         VI_UNLOCK(vp);
 2399 }
 2400 
 2401 /*
 2402  * Call VOP_INACTIVE on the vnode and manage the DOINGINACT and OWEINACT
 2403  * flags.  DOINGINACT prevents us from recursing in calls to vinactive.
 2404  * OWEINACT tracks whether a vnode missed a call to inactive due to a
 2405  * failed lock upgrade.
 2406  */
 2407 static void
 2408 vinactive(struct vnode *vp, struct thread *td)
 2409 {
 2410 
 2411         ASSERT_VOP_ELOCKED(vp, "vinactive");
 2412         ASSERT_VI_LOCKED(vp, "vinactive");
 2413         VNASSERT((vp->v_iflag & VI_DOINGINACT) == 0, vp,
 2414             ("vinactive: recursed on VI_DOINGINACT"));
 2415         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2416         vp->v_iflag |= VI_DOINGINACT;
 2417         vp->v_iflag &= ~VI_OWEINACT;
 2418         VI_UNLOCK(vp);
 2419         VOP_INACTIVE(vp, td);
 2420         VI_LOCK(vp);
 2421         VNASSERT(vp->v_iflag & VI_DOINGINACT, vp,
 2422             ("vinactive: lost VI_DOINGINACT"));
 2423         vp->v_iflag &= ~VI_DOINGINACT;
 2424 }
 2425 
 2426 /*
 2427  * Remove any vnodes in the vnode table belonging to mount point mp.
 2428  *
 2429  * If FORCECLOSE is not specified, there should not be any active ones,
 2430  * return error if any are found (nb: this is a user error, not a
 2431  * system error). If FORCECLOSE is specified, detach any active vnodes
 2432  * that are found.
 2433  *
 2434  * If WRITECLOSE is set, only flush out regular file vnodes open for
 2435  * writing.
 2436  *
 2437  * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
 2438  *
 2439  * `rootrefs' specifies the base reference count for the root vnode
 2440  * of this filesystem. The root vnode is considered busy if its
 2441  * v_usecount exceeds this value. On a successful return, vflush(, td)
 2442  * will call vrele() on the root vnode exactly rootrefs times.
 2443  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
 2444  * be zero.
 2445  */
 2446 #ifdef DIAGNOSTIC
 2447 static int busyprt = 0;         /* print out busy vnodes */
 2448 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "Print out busy vnodes");
 2449 #endif
 2450 
 2451 int
 2452 vflush( struct mount *mp, int rootrefs, int flags, struct thread *td)
 2453 {
 2454         struct vnode *vp, *mvp, *rootvp = NULL;
 2455         struct vattr vattr;
 2456         int busy = 0, error;
 2457 
 2458         CTR4(KTR_VFS, "%s: mp %p with rootrefs %d and flags %d", __func__, mp,
 2459             rootrefs, flags);
 2460         if (rootrefs > 0) {
 2461                 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
 2462                     ("vflush: bad args"));
 2463                 /*
 2464                  * Get the filesystem root vnode. We can vput() it
 2465                  * immediately, since with rootrefs > 0, it won't go away.
 2466                  */
 2467                 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rootvp)) != 0) {
 2468                         CTR2(KTR_VFS, "%s: vfs_root lookup failed with %d",
 2469                             __func__, error);
 2470                         return (error);
 2471                 }
 2472                 vput(rootvp);
 2473 
 2474         }
 2475         MNT_ILOCK(mp);
 2476 loop:
 2477         MNT_VNODE_FOREACH(vp, mp, mvp) {
 2478 
 2479                 VI_LOCK(vp);
 2480                 vholdl(vp);
 2481                 MNT_IUNLOCK(mp);
 2482                 error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE);
 2483                 if (error) {
 2484                         vdrop(vp);
 2485                         MNT_ILOCK(mp);
 2486                         MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);
 2487                         goto loop;
 2488                 }
 2489                 /*
 2490                  * Skip over a vnodes marked VV_SYSTEM.
 2491                  */
 2492                 if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
 2493                         VOP_UNLOCK(vp, 0);
 2494                         vdrop(vp);
 2495                         MNT_ILOCK(mp);
 2496                         continue;
 2497                 }
 2498                 /*
 2499                  * If WRITECLOSE is set, flush out unlinked but still open
 2500                  * files (even if open only for reading) and regular file
 2501                  * vnodes open for writing.
 2502                  */
 2503                 if (flags & WRITECLOSE) {
 2504                         if (vp->v_object != NULL) {
 2505                                 VM_OBJECT_LOCK(vp->v_object);
 2506                                 vm_object_page_clean(vp->v_object, 0, 0, 0);
 2507                                 VM_OBJECT_UNLOCK(vp->v_object);
 2508                         }
 2509                         error = VOP_FSYNC(vp, MNT_WAIT, td);
 2510                         if (error != 0) {
 2511                                 VOP_UNLOCK(vp, 0);
 2512                                 vdrop(vp);
 2513                                 MNT_VNODE_FOREACH_ABORT(mp, mvp);
 2514                                 return (error);
 2515                         }
 2516                         error = VOP_GETATTR(vp, &vattr, td->td_ucred);
 2517                         VI_LOCK(vp);
 2518 
 2519                         if ((vp->v_type == VNON ||
 2520                             (error == 0 && vattr.va_nlink > 0)) &&
 2521                             (vp->v_writecount == 0 || vp->v_type != VREG)) {
 2522                                 VOP_UNLOCK(vp, 0);
 2523                                 vdropl(vp);
 2524                                 MNT_ILOCK(mp);
 2525                                 continue;
 2526                         }
 2527                 } else
 2528                         VI_LOCK(vp);
 2529                 /*
 2530                  * With v_usecount == 0, all we need to do is clear out the
 2531                  * vnode data structures and we are done.
 2532                  *
 2533                  * If FORCECLOSE is set, forcibly close the vnode.
 2534                  */
 2535                 if (vp->v_usecount == 0 || (flags & FORCECLOSE)) {
 2536                         VNASSERT(vp->v_usecount == 0 ||
 2537                             (vp->v_type != VCHR && vp->v_type != VBLK), vp,
 2538                             ("device VNODE %p is FORCECLOSED", vp));
 2539                         vgonel(vp);
 2540                 } else {
 2541                         busy++;
 2542 #ifdef DIAGNOSTIC
 2543                         if (busyprt)
 2544                                 vprint("vflush: busy vnode", vp);
 2545 #endif
 2546                 }
 2547                 VOP_UNLOCK(vp, 0);
 2548                 vdropl(vp);
 2549                 MNT_ILOCK(mp);
 2550         }
 2551         MNT_IUNLOCK(mp);
 2552         if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
 2553                 /*
 2554                  * If just the root vnode is busy, and if its refcount
 2555                  * is equal to `rootrefs', then go ahead and kill it.
 2556                  */
 2557                 VI_LOCK(rootvp);
 2558                 KASSERT(busy > 0, ("vflush: not busy"));
 2559                 VNASSERT(rootvp->v_usecount >= rootrefs, rootvp,
 2560                     ("vflush: usecount %d < rootrefs %d",
 2561                      rootvp->v_usecount, rootrefs));
 2562                 if (busy == 1 && rootvp->v_usecount == rootrefs) {
 2563                         VOP_LOCK(rootvp, LK_EXCLUSIVE|LK_INTERLOCK);
 2564                         vgone(rootvp);
 2565                         VOP_UNLOCK(rootvp, 0);
 2566                         busy = 0;
 2567                 } else
 2568                         VI_UNLOCK(rootvp);
 2569         }
 2570         if (busy) {
 2571                 CTR2(KTR_VFS, "%s: failing as %d vnodes are busy", __func__,
 2572                     busy);
 2573                 return (EBUSY);
 2574         }
 2575         for (; rootrefs > 0; rootrefs--)
 2576                 vrele(rootvp);
 2577         return (0);
 2578 }
 2579 
 2580 /*
 2581  * Recycle an unused vnode to the front of the free list.
 2582  */
 2583 int
 2584 vrecycle(struct vnode *vp, struct thread *td)
 2585 {
 2586         int recycled;
 2587 
 2588         ASSERT_VOP_ELOCKED(vp, "vrecycle");
 2589         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2590         recycled = 0;
 2591         VI_LOCK(vp);
 2592         if (vp->v_usecount == 0) {
 2593                 recycled = 1;
 2594                 vgonel(vp);
 2595         }
 2596         VI_UNLOCK(vp);
 2597         return (recycled);
 2598 }
 2599 
 2600 /*
 2601  * Eliminate all activity associated with a vnode
 2602  * in preparation for reuse.
 2603  */
 2604 void
 2605 vgone(struct vnode *vp)
 2606 {
 2607         VI_LOCK(vp);
 2608         vgonel(vp);
 2609         VI_UNLOCK(vp);
 2610 }
 2611 
 2612 /*
 2613  * vgone, with the vp interlock held.
 2614  */
 2615 void
 2616 vgonel(struct vnode *vp)
 2617 {
 2618         struct thread *td;
 2619         int oweinact;
 2620         int active;
 2621         struct mount *mp;
 2622 
 2623         ASSERT_VOP_ELOCKED(vp, "vgonel");
 2624         ASSERT_VI_LOCKED(vp, "vgonel");
 2625         VNASSERT(vp->v_holdcnt, vp,
 2626             ("vgonel: vp %p has no reference.", vp));
 2627         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 2628         td = curthread;
 2629 
 2630         /*
 2631          * Don't vgonel if we're already doomed.
 2632          */
 2633         if (vp->v_iflag & VI_DOOMED)
 2634                 return;
 2635         vp->v_iflag |= VI_DOOMED;
 2636         /*
 2637          * Check to see if the vnode is in use.  If so, we have to call
 2638          * VOP_CLOSE() and VOP_INACTIVE().
 2639          */
 2640         active = vp->v_usecount;
 2641         oweinact = (vp->v_iflag & VI_OWEINACT);
 2642         VI_UNLOCK(vp);
 2643         /*
 2644          * Clean out any buffers associated with the vnode.
 2645          * If the flush fails, just toss the buffers.
 2646          */
 2647         mp = NULL;
 2648         if (!TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd))
 2649                 (void) vn_start_secondary_write(vp, &mp, V_WAIT);
 2650         if (vinvalbuf(vp, V_SAVE, 0, 0) != 0)
 2651                 vinvalbuf(vp, 0, 0, 0);
 2652 
 2653         /*
 2654          * If purging an active vnode, it must be closed and
 2655          * deactivated before being reclaimed.
 2656          */
 2657         if (active)
 2658                 VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
 2659         if (oweinact || active) {
 2660                 VI_LOCK(vp);
 2661                 if ((vp->v_iflag & VI_DOINGINACT) == 0)
 2662                         vinactive(vp, td);
 2663                 VI_UNLOCK(vp);
 2664         }
 2665         /*
 2666          * Reclaim the vnode.
 2667          */
 2668         if (VOP_RECLAIM(vp, td))
 2669                 panic("vgone: cannot reclaim");
 2670         if (mp != NULL)
 2671                 vn_finished_secondary_write(mp);
 2672         VNASSERT(vp->v_object == NULL, vp,
 2673             ("vop_reclaim left v_object vp=%p, tag=%s", vp, vp->v_tag));
 2674         /*
 2675          * Clear the advisory locks and wake up waiting threads.
 2676          */
 2677         lf_purgelocks(vp, &(vp->v_lockf));
 2678         /*
 2679          * Delete from old mount point vnode list.
 2680          */
 2681         delmntque(vp);
 2682         cache_purge(vp);
 2683         /*
 2684          * Done with purge, reset to the standard lock and invalidate
 2685          * the vnode.
 2686          */
 2687         VI_LOCK(vp);
 2688         vp->v_vnlock = &vp->v_lock;
 2689         vp->v_op = &dead_vnodeops;
 2690         vp->v_tag = "none";
 2691         vp->v_type = VBAD;
 2692 }
 2693 
 2694 /*
 2695  * Calculate the total number of references to a special device.
 2696  */
 2697 int
 2698 vcount(struct vnode *vp)
 2699 {
 2700         int count;
 2701 
 2702         dev_lock();
 2703         count = vp->v_rdev->si_usecount;
 2704         dev_unlock();
 2705         return (count);
 2706 }
 2707 
 2708 /*
 2709  * Same as above, but using the struct cdev *as argument
 2710  */
 2711 int
 2712 count_dev(struct cdev *dev)
 2713 {
 2714         int count;
 2715 
 2716         dev_lock();
 2717         count = dev->si_usecount;
 2718         dev_unlock();
 2719         return(count);
 2720 }
 2721 
 2722 /*
 2723  * Print out a description of a vnode.
 2724  */
 2725 static char *typename[] =
 2726 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD",
 2727  "VMARKER"};
 2728 
 2729 void
 2730 vn_printf(struct vnode *vp, const char *fmt, ...)
 2731 {
 2732         va_list ap;
 2733         char buf[256], buf2[16];
 2734         u_long flags;
 2735 
 2736         va_start(ap, fmt);
 2737         vprintf(fmt, ap);
 2738         va_end(ap);
 2739         printf("%p: ", (void *)vp);
 2740         printf("tag %s, type %s\n", vp->v_tag, typename[vp->v_type]);
 2741         printf("    usecount %d, writecount %d, refcount %d mountedhere %p\n",
 2742             vp->v_usecount, vp->v_writecount, vp->v_holdcnt, vp->v_mountedhere);
 2743         buf[0] = '\0';
 2744         buf[1] = '\0';
 2745         if (vp->v_vflag & VV_ROOT)
 2746                 strlcat(buf, "|VV_ROOT", sizeof(buf));
 2747         if (vp->v_vflag & VV_ISTTY)
 2748                 strlcat(buf, "|VV_ISTTY", sizeof(buf));
 2749         if (vp->v_vflag & VV_NOSYNC)
 2750                 strlcat(buf, "|VV_NOSYNC", sizeof(buf));
 2751         if (vp->v_vflag & VV_CACHEDLABEL)
 2752                 strlcat(buf, "|VV_CACHEDLABEL", sizeof(buf));
 2753         if (vp->v_vflag & VV_TEXT)
 2754                 strlcat(buf, "|VV_TEXT", sizeof(buf));
 2755         if (vp->v_vflag & VV_COPYONWRITE)
 2756                 strlcat(buf, "|VV_COPYONWRITE", sizeof(buf));
 2757         if (vp->v_vflag & VV_SYSTEM)
 2758                 strlcat(buf, "|VV_SYSTEM", sizeof(buf));
 2759         if (vp->v_vflag & VV_PROCDEP)
 2760                 strlcat(buf, "|VV_PROCDEP", sizeof(buf));
 2761         if (vp->v_vflag & VV_NOKNOTE)
 2762                 strlcat(buf, "|VV_NOKNOTE", sizeof(buf));
 2763         if (vp->v_vflag & VV_DELETED)
 2764                 strlcat(buf, "|VV_DELETED", sizeof(buf));
 2765         if (vp->v_vflag & VV_MD)
 2766                 strlcat(buf, "|VV_MD", sizeof(buf));
 2767         flags = vp->v_vflag & ~(VV_ROOT | VV_ISTTY | VV_NOSYNC |
 2768             VV_CACHEDLABEL | VV_TEXT | VV_COPYONWRITE | VV_SYSTEM | VV_PROCDEP |
 2769             VV_NOKNOTE | VV_DELETED | VV_MD);
 2770         if (flags != 0) {
 2771                 snprintf(buf2, sizeof(buf2), "|VV(0x%lx)", flags);
 2772                 strlcat(buf, buf2, sizeof(buf));
 2773         }
 2774         if (vp->v_iflag & VI_MOUNT)
 2775                 strlcat(buf, "|VI_MOUNT", sizeof(buf));
 2776         if (vp->v_iflag & VI_AGE)
 2777                 strlcat(buf, "|VI_AGE", sizeof(buf));
 2778         if (vp->v_iflag & VI_DOOMED)
 2779                 strlcat(buf, "|VI_DOOMED", sizeof(buf));
 2780         if (vp->v_iflag & VI_FREE)
 2781                 strlcat(buf, "|VI_FREE", sizeof(buf));
 2782         if (vp->v_iflag & VI_DOINGINACT)
 2783                 strlcat(buf, "|VI_DOINGINACT", sizeof(buf));
 2784         if (vp->v_iflag & VI_OWEINACT)
 2785                 strlcat(buf, "|VI_OWEINACT", sizeof(buf));
 2786         flags = vp->v_iflag & ~(VI_MOUNT | VI_AGE | VI_DOOMED | VI_FREE |
 2787             VI_DOINGINACT | VI_OWEINACT);
 2788         if (flags != 0) {
 2789                 snprintf(buf2, sizeof(buf2), "|VI(0x%lx)", flags);
 2790                 strlcat(buf, buf2, sizeof(buf));
 2791         }
 2792         printf("    flags (%s)\n", buf + 1);
 2793         if (mtx_owned(VI_MTX(vp)))
 2794                 printf(" VI_LOCKed");
 2795         if (vp->v_object != NULL)
 2796                 printf("    v_object %p ref %d pages %d\n",
 2797                     vp->v_object, vp->v_object->ref_count,
 2798                     vp->v_object->resident_page_count);
 2799         printf("    ");
 2800         lockmgr_printinfo(vp->v_vnlock);
 2801         if (vp->v_data != NULL)
 2802                 VOP_PRINT(vp);
 2803 }
 2804 
 2805 #ifdef DDB
 2806 /*
 2807  * List all of the locked vnodes in the system.
 2808  * Called when debugging the kernel.
 2809  */
 2810 DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
 2811 {
 2812         struct mount *mp, *nmp;
 2813         struct vnode *vp;
 2814 
 2815         /*
 2816          * Note: because this is DDB, we can't obey the locking semantics
 2817          * for these structures, which means we could catch an inconsistent
 2818          * state and dereference a nasty pointer.  Not much to be done
 2819          * about that.
 2820          */
 2821         db_printf("Locked vnodes\n");
 2822         for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
 2823                 nmp = TAILQ_NEXT(mp, mnt_list);
 2824                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 2825                         if (vp->v_type != VMARKER &&
 2826                             VOP_ISLOCKED(vp))
 2827                                 vprint("", vp);
 2828                 }
 2829                 nmp = TAILQ_NEXT(mp, mnt_list);
 2830         }
 2831 }
 2832 
 2833 /*
 2834  * Show details about the given vnode.
 2835  */
 2836 DB_SHOW_COMMAND(vnode, db_show_vnode)
 2837 {
 2838         struct vnode *vp;
 2839 
 2840         if (!have_addr)
 2841                 return;
 2842         vp = (struct vnode *)addr;
 2843         vn_printf(vp, "vnode ");
 2844 }
 2845 
 2846 /*
 2847  * Show details about the given mount point.
 2848  */
 2849 DB_SHOW_COMMAND(mount, db_show_mount)
 2850 {
 2851         struct mount *mp;
 2852         struct vfsopt *opt;
 2853         struct statfs *sp;
 2854         struct vnode *vp;
 2855         char buf[512];
 2856         u_int flags;
 2857 
 2858         if (!have_addr) {
 2859                 /* No address given, print short info about all mount points. */
 2860                 TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 2861                         db_printf("%p %s on %s (%s)\n", mp,
 2862                             mp->mnt_stat.f_mntfromname,
 2863                             mp->mnt_stat.f_mntonname,
 2864                             mp->mnt_stat.f_fstypename);
 2865                         if (db_pager_quit)
 2866                                 break;
 2867                 }
 2868                 db_printf("\nMore info: show mount <addr>\n");
 2869                 return;
 2870         }
 2871 
 2872         mp = (struct mount *)addr;
 2873         db_printf("%p %s on %s (%s)\n", mp, mp->mnt_stat.f_mntfromname,
 2874             mp->mnt_stat.f_mntonname, mp->mnt_stat.f_fstypename);
 2875 
 2876         buf[0] = '\0';
 2877         flags = mp->mnt_flag;
 2878 #define MNT_FLAG(flag)  do {                                            \
 2879         if (flags & (flag)) {                                           \
 2880                 if (buf[0] != '\0')                                     \
 2881                         strlcat(buf, ", ", sizeof(buf));                \
 2882                 strlcat(buf, (#flag) + 4, sizeof(buf));                 \
 2883                 flags &= ~(flag);                                       \
 2884         }                                                               \
 2885 } while (0)
 2886         MNT_FLAG(MNT_RDONLY);
 2887         MNT_FLAG(MNT_SYNCHRONOUS);
 2888         MNT_FLAG(MNT_NOEXEC);
 2889         MNT_FLAG(MNT_NOSUID);
 2890         MNT_FLAG(MNT_UNION);
 2891         MNT_FLAG(MNT_ASYNC);
 2892         MNT_FLAG(MNT_SUIDDIR);
 2893         MNT_FLAG(MNT_SOFTDEP);
 2894         MNT_FLAG(MNT_NOSYMFOLLOW);
 2895         MNT_FLAG(MNT_GJOURNAL);
 2896         MNT_FLAG(MNT_MULTILABEL);
 2897         MNT_FLAG(MNT_ACLS);
 2898         MNT_FLAG(MNT_NOATIME);
 2899         MNT_FLAG(MNT_NOCLUSTERR);
 2900         MNT_FLAG(MNT_NOCLUSTERW);
 2901         MNT_FLAG(MNT_NFS4ACLS);
 2902         MNT_FLAG(MNT_EXRDONLY);
 2903         MNT_FLAG(MNT_EXPORTED);
 2904         MNT_FLAG(MNT_DEFEXPORTED);
 2905         MNT_FLAG(MNT_EXPORTANON);
 2906         MNT_FLAG(MNT_EXKERB);
 2907         MNT_FLAG(MNT_EXPUBLIC);
 2908         MNT_FLAG(MNT_LOCAL);
 2909         MNT_FLAG(MNT_QUOTA);
 2910         MNT_FLAG(MNT_ROOTFS);
 2911         MNT_FLAG(MNT_USER);
 2912         MNT_FLAG(MNT_IGNORE);
 2913         MNT_FLAG(MNT_UPDATE);
 2914         MNT_FLAG(MNT_DELEXPORT);
 2915         MNT_FLAG(MNT_RELOAD);
 2916         MNT_FLAG(MNT_FORCE);
 2917         MNT_FLAG(MNT_SNAPSHOT);
 2918         MNT_FLAG(MNT_BYFSID);
 2919 #undef MNT_FLAG
 2920         if (flags != 0) {
 2921                 if (buf[0] != '\0')
 2922                         strlcat(buf, ", ", sizeof(buf));
 2923                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 2924                     "0x%08x", flags);
 2925         }
 2926         db_printf("    mnt_flag = %s\n", buf);
 2927 
 2928         buf[0] = '\0';
 2929         flags = mp->mnt_kern_flag;
 2930 #define MNT_KERN_FLAG(flag)     do {                                    \
 2931         if (flags & (flag)) {                                           \
 2932                 if (buf[0] != '\0')                                     \
 2933                         strlcat(buf, ", ", sizeof(buf));                \
 2934                 strlcat(buf, (#flag) + 5, sizeof(buf));                 \
 2935                 flags &= ~(flag);                                       \
 2936         }                                                               \
 2937 } while (0)
 2938         MNT_KERN_FLAG(MNTK_UNMOUNTF);
 2939         MNT_KERN_FLAG(MNTK_ASYNC);
 2940         MNT_KERN_FLAG(MNTK_SOFTDEP);
 2941         MNT_KERN_FLAG(MNTK_NOINSMNTQ);
 2942         MNT_KERN_FLAG(MNTK_UNMOUNT);
 2943         MNT_KERN_FLAG(MNTK_MWAIT);
 2944         MNT_KERN_FLAG(MNTK_SUSPEND);
 2945         MNT_KERN_FLAG(MNTK_SUSPEND2);
 2946         MNT_KERN_FLAG(MNTK_SUSPENDED);
 2947         MNT_KERN_FLAG(MNTK_MPSAFE);
 2948         MNT_KERN_FLAG(MNTK_NOKNOTE);
 2949         MNT_KERN_FLAG(MNTK_LOOKUP_SHARED);
 2950 #undef MNT_KERN_FLAG
 2951         if (flags != 0) {
 2952                 if (buf[0] != '\0')
 2953                         strlcat(buf, ", ", sizeof(buf));
 2954                 snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
 2955                     "0x%08x", flags);
 2956         }
 2957         db_printf("    mnt_kern_flag = %s\n", buf);
 2958 
 2959         db_printf("    mnt_opt = ");
 2960         opt = TAILQ_FIRST(mp->mnt_opt);
 2961         if (opt != NULL) {
 2962                 db_printf("%s", opt->name);
 2963                 opt = TAILQ_NEXT(opt, link);
 2964                 while (opt != NULL) {
 2965                         db_printf(", %s", opt->name);
 2966                         opt = TAILQ_NEXT(opt, link);
 2967                 }
 2968         }
 2969         db_printf("\n");
 2970 
 2971         sp = &mp->mnt_stat;
 2972         db_printf("    mnt_stat = { version=%u type=%u flags=0x%016jx "
 2973             "bsize=%ju iosize=%ju blocks=%ju bfree=%ju bavail=%jd files=%ju "
 2974             "ffree=%jd syncwrites=%ju asyncwrites=%ju syncreads=%ju "
 2975             "asyncreads=%ju namemax=%u owner=%u fsid=[%d, %d] }\n",
 2976             (u_int)sp->f_version, (u_int)sp->f_type, (uintmax_t)sp->f_flags,
 2977             (uintmax_t)sp->f_bsize, (uintmax_t)sp->f_iosize,
 2978             (uintmax_t)sp->f_blocks, (uintmax_t)sp->f_bfree,
 2979             (intmax_t)sp->f_bavail, (uintmax_t)sp->f_files,
 2980             (intmax_t)sp->f_ffree, (uintmax_t)sp->f_syncwrites,
 2981             (uintmax_t)sp->f_asyncwrites, (uintmax_t)sp->f_syncreads,
 2982             (uintmax_t)sp->f_asyncreads, (u_int)sp->f_namemax,
 2983             (u_int)sp->f_owner, (int)sp->f_fsid.val[0], (int)sp->f_fsid.val[1]);
 2984 
 2985         db_printf("    mnt_cred = { uid=%u ruid=%u",
 2986             (u_int)mp->mnt_cred->cr_uid, (u_int)mp->mnt_cred->cr_ruid);
 2987         if (jailed(mp->mnt_cred))
 2988                 db_printf(", jail=%d", mp->mnt_cred->cr_prison->pr_id);
 2989         db_printf(" }\n");
 2990         db_printf("    mnt_ref = %d\n", mp->mnt_ref);
 2991         db_printf("    mnt_gen = %d\n", mp->mnt_gen);
 2992         db_printf("    mnt_nvnodelistsize = %d\n", mp->mnt_nvnodelistsize);
 2993         db_printf("    mnt_writeopcount = %d\n", mp->mnt_writeopcount);
 2994         db_printf("    mnt_noasync = %u\n", mp->mnt_noasync);
 2995         db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
 2996         db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
 2997         db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
 2998         db_printf("    mnt_secondary_writes = %d\n", mp->mnt_secondary_writes);
 2999         db_printf("    mnt_secondary_accwrites = %d\n",
 3000             mp->mnt_secondary_accwrites);
 3001         db_printf("    mnt_gjprovider = %s\n",
 3002             mp->mnt_gjprovider != NULL ? mp->mnt_gjprovider : "NULL");
 3003         db_printf("\n");
 3004 
 3005         TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3006                 if (vp->v_type != VMARKER) {
 3007                         vn_printf(vp, "vnode ");
 3008                         if (db_pager_quit)
 3009                                 break;
 3010                 }
 3011         }
 3012 }
 3013 #endif  /* DDB */
 3014 
 3015 /*
 3016  * Fill in a struct xvfsconf based on a struct vfsconf.
 3017  */
 3018 static void
 3019 vfsconf2x(struct vfsconf *vfsp, struct xvfsconf *xvfsp)
 3020 {
 3021 
 3022         strcpy(xvfsp->vfc_name, vfsp->vfc_name);
 3023         xvfsp->vfc_typenum = vfsp->vfc_typenum;
 3024         xvfsp->vfc_refcount = vfsp->vfc_refcount;
 3025         xvfsp->vfc_flags = vfsp->vfc_flags;
 3026         /*
 3027          * These are unused in userland, we keep them
 3028          * to not break binary compatibility.
 3029          */
 3030         xvfsp->vfc_vfsops = NULL;
 3031         xvfsp->vfc_next = NULL;
 3032 }
 3033 
 3034 /*
 3035  * Top level filesystem related information gathering.
 3036  */
 3037 static int
 3038 sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
 3039 {
 3040         struct vfsconf *vfsp;
 3041         struct xvfsconf xvfsp;
 3042         int error;
 3043 
 3044         error = 0;
 3045         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3046                 bzero(&xvfsp, sizeof(xvfsp));
 3047                 vfsconf2x(vfsp, &xvfsp);
 3048                 error = SYSCTL_OUT(req, &xvfsp, sizeof xvfsp);
 3049                 if (error)
 3050                         break;
 3051         }
 3052         return (error);
 3053 }
 3054 
 3055 SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
 3056     "S,xvfsconf", "List of all configured filesystems");
 3057 
 3058 #ifndef BURN_BRIDGES
 3059 static int      sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
 3060 
 3061 static int
 3062 vfs_sysctl(SYSCTL_HANDLER_ARGS)
 3063 {
 3064         int *name = (int *)arg1 - 1;    /* XXX */
 3065         u_int namelen = arg2 + 1;       /* XXX */
 3066         struct vfsconf *vfsp;
 3067         struct xvfsconf xvfsp;
 3068 
 3069         printf("WARNING: userland calling deprecated sysctl, "
 3070             "please rebuild world\n");
 3071 
 3072 #if 1 || defined(COMPAT_PRELITE2)
 3073         /* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
 3074         if (namelen == 1)
 3075                 return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
 3076 #endif
 3077 
 3078         switch (name[1]) {
 3079         case VFS_MAXTYPENUM:
 3080                 if (namelen != 2)
 3081                         return (ENOTDIR);
 3082                 return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
 3083         case VFS_CONF:
 3084                 if (namelen != 3)
 3085                         return (ENOTDIR);       /* overloaded */
 3086                 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
 3087                         if (vfsp->vfc_typenum == name[2])
 3088                                 break;
 3089                 if (vfsp == NULL)
 3090                         return (EOPNOTSUPP);
 3091                 bzero(&xvfsp, sizeof(xvfsp));
 3092                 vfsconf2x(vfsp, &xvfsp);
 3093                 return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 3094         }
 3095         return (EOPNOTSUPP);
 3096 }
 3097 
 3098 static SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP,
 3099     vfs_sysctl, "Generic filesystem");
 3100 
 3101 #if 1 || defined(COMPAT_PRELITE2)
 3102 
 3103 static int
 3104 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
 3105 {
 3106         int error;
 3107         struct vfsconf *vfsp;
 3108         struct ovfsconf ovfs;
 3109 
 3110         TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
 3111                 bzero(&ovfs, sizeof(ovfs));
 3112                 ovfs.vfc_vfsops = vfsp->vfc_vfsops;     /* XXX used as flag */
 3113                 strcpy(ovfs.vfc_name, vfsp->vfc_name);
 3114                 ovfs.vfc_index = vfsp->vfc_typenum;
 3115                 ovfs.vfc_refcount = vfsp->vfc_refcount;
 3116                 ovfs.vfc_flags = vfsp->vfc_flags;
 3117                 error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
 3118                 if (error)
 3119                         return error;
 3120         }
 3121         return 0;
 3122 }
 3123 
 3124 #endif /* 1 || COMPAT_PRELITE2 */
 3125 #endif /* !BURN_BRIDGES */
 3126 
 3127 #define KINFO_VNODESLOP         10
 3128 #ifdef notyet
 3129 /*
 3130  * Dump vnode list (via sysctl).
 3131  */
 3132 /* ARGSUSED */
 3133 static int
 3134 sysctl_vnode(SYSCTL_HANDLER_ARGS)
 3135 {
 3136         struct xvnode *xvn;
 3137         struct mount *mp;
 3138         struct vnode *vp;
 3139         int error, len, n;
 3140 
 3141         /*
 3142          * Stale numvnodes access is not fatal here.
 3143          */
 3144         req->lock = 0;
 3145         len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
 3146         if (!req->oldptr)
 3147                 /* Make an estimate */
 3148                 return (SYSCTL_OUT(req, 0, len));
 3149 
 3150         error = sysctl_wire_old_buffer(req, 0);
 3151         if (error != 0)
 3152                 return (error);
 3153         xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
 3154         n = 0;
 3155         mtx_lock(&mountlist_mtx);
 3156         TAILQ_FOREACH(mp, &mountlist, mnt_list) {
 3157                 if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
 3158                         continue;
 3159                 MNT_ILOCK(mp);
 3160                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 3161                         if (n == len)
 3162                                 break;
 3163                         vref(vp);
 3164                         xvn[n].xv_size = sizeof *xvn;
 3165                         xvn[n].xv_vnode = vp;
 3166                         xvn[n].xv_id = 0;       /* XXX compat */
 3167 #define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
 3168                         XV_COPY(usecount);
 3169                         XV_COPY(writecount);
 3170                         XV_COPY(holdcnt);
 3171                         XV_COPY(mount);
 3172                         XV_COPY(numoutput);
 3173                         XV_COPY(type);
 3174 #undef XV_COPY
 3175                         xvn[n].xv_flag = vp->v_vflag;
 3176 
 3177                         switch (vp->v_type) {
 3178                         case VREG:
 3179                         case VDIR:
 3180                         case VLNK:
 3181                                 break;
 3182                         case VBLK:
 3183                         case VCHR:
 3184                                 if (vp->v_rdev == NULL) {
 3185                                         vrele(vp);
 3186                                         continue;
 3187                                 }
 3188                                 xvn[n].xv_dev = dev2udev(vp->v_rdev);
 3189                                 break;
 3190                         case VSOCK:
 3191                                 xvn[n].xv_socket = vp->v_socket;
 3192                                 break;
 3193                         case VFIFO:
 3194                                 xvn[n].xv_fifo = vp->v_fifoinfo;
 3195                                 break;
 3196                         case VNON:
 3197                         case VBAD:
 3198                         default:
 3199                                 /* shouldn't happen? */
 3200                                 vrele(vp);
 3201                                 continue;
 3202                         }
 3203                         vrele(vp);
 3204                         ++n;
 3205                 }
 3206                 MNT_IUNLOCK(mp);
 3207                 mtx_lock(&mountlist_mtx);
 3208                 vfs_unbusy(mp);
 3209                 if (n == len)
 3210                         break;
 3211         }
 3212         mtx_unlock(&mountlist_mtx);
 3213 
 3214         error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
 3215         free(xvn, M_TEMP);
 3216         return (error);
 3217 }
 3218 
 3219 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
 3220     0, 0, sysctl_vnode, "S,xvnode", "");
 3221 #endif
 3222 
 3223 /*
 3224  * Unmount all filesystems. The list is traversed in reverse order
 3225  * of mounting to avoid dependencies.
 3226  */
 3227 void
 3228 vfs_unmountall(void)
 3229 {
 3230         struct mount *mp;
 3231         struct thread *td;
 3232         int error;
 3233 
 3234         KASSERT(curthread != NULL, ("vfs_unmountall: NULL curthread"));
 3235         CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__);
 3236         td = curthread;
 3237 
 3238         /*
 3239          * Since this only runs when rebooting, it is not interlocked.
 3240          */
 3241         while(!TAILQ_EMPTY(&mountlist)) {
 3242                 mp = TAILQ_LAST(&mountlist, mntlist);
 3243                 error = dounmount(mp, MNT_FORCE, td);
 3244                 if (error) {
 3245                         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 3246                         /*
 3247                          * XXX: Due to the way in which we mount the root
 3248                          * file system off of devfs, devfs will generate a
 3249                          * "busy" warning when we try to unmount it before
 3250                          * the root.  Don't print a warning as a result in
 3251                          * order to avoid false positive errors that may
 3252                          * cause needless upset.
 3253                          */
 3254                         if (strcmp(mp->mnt_vfc->vfc_name, "devfs") != 0) {
 3255                                 printf("unmount of %s failed (",
 3256                                     mp->mnt_stat.f_mntonname);
 3257                                 if (error == EBUSY)
 3258                                         printf("BUSY)\n");
 3259                                 else
 3260                                         printf("%d)\n", error);
 3261                         }
 3262                 } else {
 3263                         /* The unmount has removed mp from the mountlist */
 3264                 }
 3265         }
 3266 }
 3267 
 3268 /*
 3269  * perform msync on all vnodes under a mount point
 3270  * the mount point must be locked.
 3271  */
 3272 void
 3273 vfs_msync(struct mount *mp, int flags)
 3274 {
 3275         struct vnode *vp, *mvp;
 3276         struct vm_object *obj;
 3277 
 3278         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
 3279         MNT_ILOCK(mp);
 3280         MNT_VNODE_FOREACH(vp, mp, mvp) {
 3281                 VI_LOCK(vp);
 3282                 obj = vp->v_object;
 3283                 if (obj != NULL && (obj->flags & OBJ_MIGHTBEDIRTY) != 0 &&
 3284                     (flags == MNT_WAIT || VOP_ISLOCKED(vp) == 0)) {
 3285                         MNT_IUNLOCK(mp);
 3286                         if (!vget(vp,
 3287                             LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
 3288                             curthread)) {
 3289                                 if (vp->v_vflag & VV_NOSYNC) {  /* unlinked */
 3290                                         vput(vp);
 3291                                         MNT_ILOCK(mp);
 3292                                         continue;
 3293                                 }
 3294 
 3295                                 obj = vp->v_object;
 3296                                 if (obj != NULL) {
 3297                                         VM_OBJECT_LOCK(obj);
 3298                                         vm_object_page_clean(obj, 0, 0,
 3299                                             flags == MNT_WAIT ?
 3300                                             OBJPC_SYNC : OBJPC_NOSYNC);
 3301                                         VM_OBJECT_UNLOCK(obj);
 3302                                 }
 3303                                 vput(vp);
 3304                         }
 3305                         MNT_ILOCK(mp);
 3306                 } else
 3307                         VI_UNLOCK(vp);
 3308         }
 3309         MNT_IUNLOCK(mp);
 3310 }
 3311 
 3312 /*
 3313  * Mark a vnode as free, putting it up for recycling.
 3314  */
 3315 static void
 3316 vfree(struct vnode *vp)
 3317 {
 3318 
 3319         ASSERT_VI_LOCKED(vp, "vfree");
 3320         mtx_lock(&vnode_free_list_mtx);
 3321         VNASSERT(vp->v_op != NULL, vp, ("vfree: vnode already reclaimed."));
 3322         VNASSERT((vp->v_iflag & VI_FREE) == 0, vp, ("vnode already free"));
 3323         VNASSERT(VSHOULDFREE(vp), vp, ("vfree: freeing when we shouldn't"));
 3324         VNASSERT((vp->v_iflag & VI_DOOMED) == 0, vp,
 3325             ("vfree: Freeing doomed vnode"));
 3326         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3327         if (vp->v_iflag & VI_AGE) {
 3328                 TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
 3329         } else {
 3330                 TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 3331         }
 3332         freevnodes++;
 3333         vp->v_iflag &= ~VI_AGE;
 3334         vp->v_iflag |= VI_FREE;
 3335         mtx_unlock(&vnode_free_list_mtx);
 3336 }
 3337 
 3338 /*
 3339  * Opposite of vfree() - mark a vnode as in use.
 3340  */
 3341 static void
 3342 vbusy(struct vnode *vp)
 3343 {
 3344         ASSERT_VI_LOCKED(vp, "vbusy");
 3345         VNASSERT((vp->v_iflag & VI_FREE) != 0, vp, ("vnode not free"));
 3346         VNASSERT(vp->v_op != NULL, vp, ("vbusy: vnode already reclaimed."));
 3347         CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 3348 
 3349         mtx_lock(&vnode_free_list_mtx);
 3350         TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
 3351         freevnodes--;
 3352         vp->v_iflag &= ~(VI_FREE|VI_AGE);
 3353         mtx_unlock(&vnode_free_list_mtx);
 3354 }
 3355 
 3356 static void
 3357 destroy_vpollinfo(struct vpollinfo *vi)
 3358 {
 3359         seldrain(&vi->vpi_selinfo);
 3360         knlist_destroy(&vi->vpi_selinfo.si_note);
 3361         mtx_destroy(&vi->vpi_lock);
 3362         uma_zfree(vnodepoll_zone, vi);
 3363 }
 3364 
 3365 /*
 3366  * Initalize per-vnode helper structure to hold poll-related state.
 3367  */
 3368 void
 3369 v_addpollinfo(struct vnode *vp)
 3370 {
 3371         struct vpollinfo *vi;
 3372 
 3373         if (vp->v_pollinfo != NULL)
 3374                 return;
 3375         vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
 3376         mtx_init(&vi->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
 3377         knlist_init(&vi->vpi_selinfo.si_note, vp, vfs_knllock,
 3378             vfs_knlunlock, vfs_knl_assert_locked, vfs_knl_assert_unlocked);
 3379         VI_LOCK(vp);
 3380         if (vp->v_pollinfo != NULL) {
 3381                 VI_UNLOCK(vp);
 3382                 destroy_vpollinfo(vi);
 3383                 return;
 3384         }
 3385         vp->v_pollinfo = vi;
 3386         VI_UNLOCK(vp);
 3387 }
 3388 
 3389 /*
 3390  * Record a process's interest in events which might happen to
 3391  * a vnode.  Because poll uses the historic select-style interface
 3392  * internally, this routine serves as both the ``check for any
 3393  * pending events'' and the ``record my interest in future events''
 3394  * functions.  (These are done together, while the lock is held,
 3395  * to avoid race conditions.)
 3396  */
 3397 int
 3398 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
 3399 {
 3400 
 3401         v_addpollinfo(vp);
 3402         mtx_lock(&vp->v_pollinfo->vpi_lock);
 3403         if (vp->v_pollinfo->vpi_revents & events) {
 3404                 /*
 3405                  * This leaves events we are not interested
 3406                  * in available for the other process which
 3407                  * which presumably had requested them
 3408                  * (otherwise they would never have been
 3409                  * recorded).
 3410                  */
 3411                 events &= vp->v_pollinfo->vpi_revents;
 3412                 vp->v_pollinfo->vpi_revents &= ~events;
 3413 
 3414                 mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3415                 return (events);
 3416         }
 3417         vp->v_pollinfo->vpi_events |= events;
 3418         selrecord(td, &vp->v_pollinfo->vpi_selinfo);
 3419         mtx_unlock(&vp->v_pollinfo->vpi_lock);
 3420         return (0);
 3421 }
 3422 
 3423 /*
 3424  * Routine to create and manage a filesystem syncer vnode.
 3425  */
 3426 #define sync_close ((int (*)(struct  vop_close_args *))nullop)
 3427 static int      sync_fsync(struct  vop_fsync_args *);
 3428 static int      sync_inactive(struct  vop_inactive_args *);
 3429 static int      sync_reclaim(struct  vop_reclaim_args *);
 3430 
 3431 static struct vop_vector sync_vnodeops = {
 3432         .vop_bypass =   VOP_EOPNOTSUPP,
 3433         .vop_close =    sync_close,             /* close */
 3434         .vop_fsync =    sync_fsync,             /* fsync */
 3435         .vop_inactive = sync_inactive,  /* inactive */
 3436         .vop_reclaim =  sync_reclaim,   /* reclaim */
 3437         .vop_lock1 =    vop_stdlock,    /* lock */
 3438         .vop_unlock =   vop_stdunlock,  /* unlock */
 3439         .vop_islocked = vop_stdislocked,        /* islocked */
 3440 };
 3441 
 3442 /*
 3443  * Create a new filesystem syncer vnode for the specified mount point.
 3444  */
 3445 int
 3446 vfs_allocate_syncvnode(struct mount *mp)
 3447 {
 3448         struct vnode *vp;
 3449         struct bufobj *bo;
 3450         static long start, incr, next;
 3451         int error;
 3452 
 3453         /* Allocate a new vnode */
 3454         if ((error = getnewvnode("syncer", mp, &sync_vnodeops, &vp)) != 0) {
 3455                 mp->mnt_syncer = NULL;
 3456                 return (error);
 3457         }
 3458         vp->v_type = VNON;
 3459         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3460         vp->v_vflag |= VV_FORCEINSMQ;
 3461         error = insmntque(vp, mp);
 3462         if (error != 0)
 3463                 panic("vfs_allocate_syncvnode: insmntque failed");
 3464         vp->v_vflag &= ~VV_FORCEINSMQ;
 3465         VOP_UNLOCK(vp, 0);
 3466         /*
 3467          * Place the vnode onto the syncer worklist. We attempt to
 3468          * scatter them about on the list so that they will go off
 3469          * at evenly distributed times even if all the filesystems
 3470          * are mounted at once.
 3471          */
 3472         next += incr;
 3473         if (next == 0 || next > syncer_maxdelay) {
 3474                 start /= 2;
 3475                 incr /= 2;
 3476                 if (start == 0) {
 3477                         start = syncer_maxdelay / 2;
 3478                         incr = syncer_maxdelay;
 3479                 }
 3480                 next = start;
 3481         }
 3482         bo = &vp->v_bufobj;
 3483         BO_LOCK(bo);
 3484         vn_syncer_add_to_worklist(bo, syncdelay > 0 ? next % syncdelay : 0);
 3485         /* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
 3486         mtx_lock(&sync_mtx);
 3487         sync_vnode_count++;
 3488         mtx_unlock(&sync_mtx);
 3489         BO_UNLOCK(bo);
 3490         mp->mnt_syncer = vp;
 3491         return (0);
 3492 }
 3493 
 3494 /*
 3495  * Do a lazy sync of the filesystem.
 3496  */
 3497 static int
 3498 sync_fsync(struct vop_fsync_args *ap)
 3499 {
 3500         struct vnode *syncvp = ap->a_vp;
 3501         struct mount *mp = syncvp->v_mount;
 3502         int error, save;
 3503         struct bufobj *bo;
 3504 
 3505         /*
 3506          * We only need to do something if this is a lazy evaluation.
 3507          */
 3508         if (ap->a_waitfor != MNT_LAZY)
 3509                 return (0);
 3510 
 3511         /*
 3512          * Move ourselves to the back of the sync list.
 3513          */
 3514         bo = &syncvp->v_bufobj;
 3515         BO_LOCK(bo);
 3516         vn_syncer_add_to_worklist(bo, syncdelay);
 3517         BO_UNLOCK(bo);
 3518 
 3519         /*
 3520          * Walk the list of vnodes pushing all that are dirty and
 3521          * not already on the sync list.
 3522          */
 3523         mtx_lock(&mountlist_mtx);
 3524         if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK) != 0) {
 3525                 mtx_unlock(&mountlist_mtx);
 3526                 return (0);
 3527         }
 3528         if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
 3529                 vfs_unbusy(mp);
 3530                 return (0);
 3531         }
 3532         save = curthread_pflags_set(TDP_SYNCIO);
 3533         vfs_msync(mp, MNT_NOWAIT);
 3534         error = VFS_SYNC(mp, MNT_LAZY);
 3535         curthread_pflags_restore(save);
 3536         vn_finished_write(mp);
 3537         vfs_unbusy(mp);
 3538         return (error);
 3539 }
 3540 
 3541 /*
 3542  * The syncer vnode is no referenced.
 3543  */
 3544 static int
 3545 sync_inactive(struct vop_inactive_args *ap)
 3546 {
 3547 
 3548         vgone(ap->a_vp);
 3549         return (0);
 3550 }
 3551 
 3552 /*
 3553  * The syncer vnode is no longer needed and is being decommissioned.
 3554  *
 3555  * Modifications to the worklist must be protected by sync_mtx.
 3556  */
 3557 static int
 3558 sync_reclaim(struct vop_reclaim_args *ap)
 3559 {
 3560         struct vnode *vp = ap->a_vp;
 3561         struct bufobj *bo;
 3562 
 3563         bo = &vp->v_bufobj;
 3564         BO_LOCK(bo);
 3565         vp->v_mount->mnt_syncer = NULL;
 3566         if (bo->bo_flag & BO_ONWORKLST) {
 3567                 mtx_lock(&sync_mtx);
 3568                 LIST_REMOVE(bo, bo_synclist);
 3569                 syncer_worklist_len--;
 3570                 sync_vnode_count--;
 3571                 mtx_unlock(&sync_mtx);
 3572                 bo->bo_flag &= ~BO_ONWORKLST;
 3573         }
 3574         BO_UNLOCK(bo);
 3575 
 3576         return (0);
 3577 }
 3578 
 3579 /*
 3580  * Check if vnode represents a disk device
 3581  */
 3582 int
 3583 vn_isdisk(struct vnode *vp, int *errp)
 3584 {
 3585         int error;
 3586 
 3587         error = 0;
 3588         dev_lock();
 3589         if (vp->v_type != VCHR)
 3590                 error = ENOTBLK;
 3591         else if (vp->v_rdev == NULL)
 3592                 error = ENXIO;
 3593         else if (vp->v_rdev->si_devsw == NULL)
 3594                 error = ENXIO;
 3595         else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
 3596                 error = ENOTBLK;
 3597         dev_unlock();
 3598         if (errp != NULL)
 3599                 *errp = error;
 3600         return (error == 0);
 3601 }
 3602 
 3603 /*
 3604  * Common filesystem object access control check routine.  Accepts a
 3605  * vnode's type, "mode", uid and gid, requested access mode, credentials,
 3606  * and optional call-by-reference privused argument allowing vaccess()
 3607  * to indicate to the caller whether privilege was used to satisfy the
 3608  * request (obsoleted).  Returns 0 on success, or an errno on failure.
 3609  */
 3610 int
 3611 vaccess(enum vtype type, mode_t file_mode, uid_t file_uid, gid_t file_gid,
 3612     accmode_t accmode, struct ucred *cred, int *privused)
 3613 {
 3614         accmode_t dac_granted;
 3615         accmode_t priv_granted;
 3616 
 3617         KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND)) == 0,
 3618             ("invalid bit in accmode"));
 3619 
 3620         /*
 3621          * Look for a normal, non-privileged way to access the file/directory
 3622          * as requested.  If it exists, go with that.
 3623          */
 3624 
 3625         if (privused != NULL)
 3626                 *privused = 0;
 3627 
 3628         dac_granted = 0;
 3629 
 3630         /* Check the owner. */
 3631         if (cred->cr_uid == file_uid) {
 3632                 dac_granted |= VADMIN;
 3633                 if (file_mode & S_IXUSR)
 3634                         dac_granted |= VEXEC;
 3635                 if (file_mode & S_IRUSR)
 3636                         dac_granted |= VREAD;
 3637                 if (file_mode & S_IWUSR)
 3638                         dac_granted |= (VWRITE | VAPPEND);
 3639 
 3640                 if ((accmode & dac_granted) == accmode)
 3641                         return (0);
 3642 
 3643                 goto privcheck;
 3644         }
 3645 
 3646         /* Otherwise, check the groups (first match) */
 3647         if (groupmember(file_gid, cred)) {
 3648                 if (file_mode & S_IXGRP)
 3649                         dac_granted |= VEXEC;
 3650                 if (file_mode & S_IRGRP)
 3651                         dac_granted |= VREAD;
 3652                 if (file_mode & S_IWGRP)
 3653                         dac_granted |= (VWRITE | VAPPEND);
 3654 
 3655                 if ((accmode & dac_granted) == accmode)
 3656                         return (0);
 3657 
 3658                 goto privcheck;
 3659         }
 3660 
 3661         /* Otherwise, check everyone else. */
 3662         if (file_mode & S_IXOTH)
 3663                 dac_granted |= VEXEC;
 3664         if (file_mode & S_IROTH)
 3665                 dac_granted |= VREAD;
 3666         if (file_mode & S_IWOTH)
 3667                 dac_granted |= (VWRITE | VAPPEND);
 3668         if ((accmode & dac_granted) == accmode)
 3669                 return (0);
 3670 
 3671 privcheck:
 3672         /*
 3673          * Build a privilege mask to determine if the set of privileges
 3674          * satisfies the requirements when combined with the granted mask
 3675          * from above.  For each privilege, if the privilege is required,
 3676          * bitwise or the request type onto the priv_granted mask.
 3677          */
 3678         priv_granted = 0;
 3679 
 3680         if (type == VDIR) {
 3681                 /*
 3682                  * For directories, use PRIV_VFS_LOOKUP to satisfy VEXEC
 3683                  * requests, instead of PRIV_VFS_EXEC.
 3684                  */
 3685                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3686                     !priv_check_cred(cred, PRIV_VFS_LOOKUP, 0))
 3687                         priv_granted |= VEXEC;
 3688         } else {
 3689                 if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
 3690                     !priv_check_cred(cred, PRIV_VFS_EXEC, 0))
 3691                         priv_granted |= VEXEC;
 3692         }
 3693 
 3694         if ((accmode & VREAD) && ((dac_granted & VREAD) == 0) &&
 3695             !priv_check_cred(cred, PRIV_VFS_READ, 0))
 3696                 priv_granted |= VREAD;
 3697 
 3698         if ((accmode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
 3699             !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
 3700                 priv_granted |= (VWRITE | VAPPEND);
 3701 
 3702         if ((accmode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
 3703             !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
 3704                 priv_granted |= VADMIN;
 3705 
 3706         if ((accmode & (priv_granted | dac_granted)) == accmode) {
 3707                 /* XXX audit: privilege used */
 3708                 if (privused != NULL)
 3709                         *privused = 1;
 3710                 return (0);
 3711         }
 3712 
 3713         return ((accmode & VADMIN) ? EPERM : EACCES);
 3714 }
 3715 
 3716 /*
 3717  * Credential check based on process requesting service, and per-attribute
 3718  * permissions.
 3719  */
 3720 int
 3721 extattr_check_cred(struct vnode *vp, int attrnamespace, struct ucred *cred,
 3722     struct thread *td, accmode_t accmode)
 3723 {
 3724 
 3725         /*
 3726          * Kernel-invoked always succeeds.
 3727          */
 3728         if (cred == NOCRED)
 3729                 return (0);
 3730 
 3731         /*
 3732          * Do not allow privileged processes in jail to directly manipulate
 3733          * system attributes.
 3734          */
 3735         switch (attrnamespace) {
 3736         case EXTATTR_NAMESPACE_SYSTEM:
 3737                 /* Potentially should be: return (EPERM); */
 3738                 return (priv_check_cred(cred, PRIV_VFS_EXTATTR_SYSTEM, 0));
 3739         case EXTATTR_NAMESPACE_USER:
 3740                 return (VOP_ACCESS(vp, accmode, cred, td));
 3741         default:
 3742                 return (EPERM);
 3743         }
 3744 }
 3745 
 3746 #ifdef DEBUG_VFS_LOCKS
 3747 /*
 3748  * This only exists to supress warnings from unlocked specfs accesses.  It is
 3749  * no longer ok to have an unlocked VFS.
 3750  */
 3751 #define IGNORE_LOCK(vp) (panicstr != NULL || (vp) == NULL ||            \
 3752         (vp)->v_type == VCHR || (vp)->v_type == VBAD)
 3753 
 3754 int vfs_badlock_ddb = 1;        /* Drop into debugger on violation. */
 3755 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0,
 3756     "Drop into debugger on lock violation");
 3757 
 3758 int vfs_badlock_mutex = 1;      /* Check for interlock across VOPs. */
 3759 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex,
 3760     0, "Check for interlock across VOPs");
 3761 
 3762 int vfs_badlock_print = 1;      /* Print lock violations. */
 3763 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print,
 3764     0, "Print lock violations");
 3765 
 3766 #ifdef KDB
 3767 int vfs_badlock_backtrace = 1;  /* Print backtrace at lock violations. */
 3768 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW,
 3769     &vfs_badlock_backtrace, 0, "Print backtrace at lock violations");
 3770 #endif
 3771 
 3772 static void
 3773 vfs_badlock(const char *msg, const char *str, struct vnode *vp)
 3774 {
 3775 
 3776 #ifdef KDB
 3777         if (vfs_badlock_backtrace)
 3778                 kdb_backtrace();
 3779 #endif
 3780         if (vfs_badlock_print)
 3781                 printf("%s: %p %s\n", str, (void *)vp, msg);
 3782         if (vfs_badlock_ddb)
 3783                 kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3784 }
 3785 
 3786 void
 3787 assert_vi_locked(struct vnode *vp, const char *str)
 3788 {
 3789 
 3790         if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
 3791                 vfs_badlock("interlock is not locked but should be", str, vp);
 3792 }
 3793 
 3794 void
 3795 assert_vi_unlocked(struct vnode *vp, const char *str)
 3796 {
 3797 
 3798         if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
 3799                 vfs_badlock("interlock is locked but should not be", str, vp);
 3800 }
 3801 
 3802 void
 3803 assert_vop_locked(struct vnode *vp, const char *str)
 3804 {
 3805 
 3806         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == 0)
 3807                 vfs_badlock("is not locked but should be", str, vp);
 3808 }
 3809 
 3810 void
 3811 assert_vop_unlocked(struct vnode *vp, const char *str)
 3812 {
 3813 
 3814         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
 3815                 vfs_badlock("is locked but should not be", str, vp);
 3816 }
 3817 
 3818 void
 3819 assert_vop_elocked(struct vnode *vp, const char *str)
 3820 {
 3821 
 3822         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
 3823                 vfs_badlock("is not exclusive locked but should be", str, vp);
 3824 }
 3825 
 3826 #if 0
 3827 void
 3828 assert_vop_elocked_other(struct vnode *vp, const char *str)
 3829 {
 3830 
 3831         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLOTHER)
 3832                 vfs_badlock("is not exclusive locked by another thread",
 3833                     str, vp);
 3834 }
 3835 
 3836 void
 3837 assert_vop_slocked(struct vnode *vp, const char *str)
 3838 {
 3839 
 3840         if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_SHARED)
 3841                 vfs_badlock("is not locked shared but should be", str, vp);
 3842 }
 3843 #endif /* 0 */
 3844 #endif /* DEBUG_VFS_LOCKS */
 3845 
 3846 void
 3847 vop_rename_fail(struct vop_rename_args *ap)
 3848 {
 3849 
 3850         if (ap->a_tvp != NULL)
 3851                 vput(ap->a_tvp);
 3852         if (ap->a_tdvp == ap->a_tvp)
 3853                 vrele(ap->a_tdvp);
 3854         else
 3855                 vput(ap->a_tdvp);
 3856         vrele(ap->a_fdvp);
 3857         vrele(ap->a_fvp);
 3858 }
 3859 
 3860 void
 3861 vop_rename_pre(void *ap)
 3862 {
 3863         struct vop_rename_args *a = ap;
 3864 
 3865 #ifdef DEBUG_VFS_LOCKS
 3866         if (a->a_tvp)
 3867                 ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
 3868         ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
 3869         ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
 3870         ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
 3871 
 3872         /* Check the source (from). */
 3873         if (a->a_tdvp->v_vnlock != a->a_fdvp->v_vnlock &&
 3874             (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fdvp->v_vnlock))
 3875                 ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
 3876         if (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fvp->v_vnlock)
 3877                 ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: fvp locked");
 3878 
 3879         /* Check the target. */
 3880         if (a->a_tvp)
 3881                 ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
 3882         ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
 3883 #endif
 3884         if (a->a_tdvp != a->a_fdvp)
 3885                 vhold(a->a_fdvp);
 3886         if (a->a_tvp != a->a_fvp)
 3887                 vhold(a->a_fvp);
 3888         vhold(a->a_tdvp);
 3889         if (a->a_tvp)
 3890                 vhold(a->a_tvp);
 3891 }
 3892 
 3893 void
 3894 vop_strategy_pre(void *ap)
 3895 {
 3896 #ifdef DEBUG_VFS_LOCKS
 3897         struct vop_strategy_args *a;
 3898         struct buf *bp;
 3899 
 3900         a = ap;
 3901         bp = a->a_bp;
 3902 
 3903         /*
 3904          * Cluster ops lock their component buffers but not the IO container.
 3905          */
 3906         if ((bp->b_flags & B_CLUSTER) != 0)
 3907                 return;
 3908 
 3909         if (panicstr == NULL && !BUF_ISLOCKED(bp)) {
 3910                 if (vfs_badlock_print)
 3911                         printf(
 3912                             "VOP_STRATEGY: bp is not locked but should be\n");
 3913                 if (vfs_badlock_ddb)
 3914                         kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
 3915         }
 3916 #endif
 3917 }
 3918 
 3919 void
 3920 vop_lookup_pre(void *ap)
 3921 {
 3922 #ifdef DEBUG_VFS_LOCKS
 3923         struct vop_lookup_args *a;
 3924         struct vnode *dvp;
 3925 
 3926         a = ap;
 3927         dvp = a->a_dvp;
 3928         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
 3929         ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
 3930 #endif
 3931 }
 3932 
 3933 void
 3934 vop_lookup_post(void *ap, int rc)
 3935 {
 3936 #ifdef DEBUG_VFS_LOCKS
 3937         struct vop_lookup_args *a;
 3938         struct vnode *dvp;
 3939         struct vnode *vp;
 3940 
 3941         a = ap;
 3942         dvp = a->a_dvp;
 3943         vp = *(a->a_vpp);
 3944 
 3945         ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
 3946         ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
 3947 
 3948         if (!rc)
 3949                 ASSERT_VOP_LOCKED(vp, "VOP_LOOKUP (child)");
 3950 #endif
 3951 }
 3952 
 3953 void
 3954 vop_lock_pre(void *ap)
 3955 {
 3956 #ifdef DEBUG_VFS_LOCKS
 3957         struct vop_lock1_args *a = ap;
 3958 
 3959         if ((a->a_flags & LK_INTERLOCK) == 0)
 3960                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 3961         else
 3962                 ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
 3963 #endif
 3964 }
 3965 
 3966 void
 3967 vop_lock_post(void *ap, int rc)
 3968 {
 3969 #ifdef DEBUG_VFS_LOCKS
 3970         struct vop_lock1_args *a = ap;
 3971 
 3972         ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
 3973         if (rc == 0)
 3974                 ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
 3975 #endif
 3976 }
 3977 
 3978 void
 3979 vop_unlock_pre(void *ap)
 3980 {
 3981 #ifdef DEBUG_VFS_LOCKS
 3982         struct vop_unlock_args *a = ap;
 3983 
 3984         if (a->a_flags & LK_INTERLOCK)
 3985                 ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
 3986         ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
 3987 #endif
 3988 }
 3989 
 3990 void
 3991 vop_unlock_post(void *ap, int rc)
 3992 {
 3993 #ifdef DEBUG_VFS_LOCKS
 3994         struct vop_unlock_args *a = ap;
 3995 
 3996         if (a->a_flags & LK_INTERLOCK)
 3997                 ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
 3998 #endif
 3999 }
 4000 
 4001 void
 4002 vop_create_post(void *ap, int rc)
 4003 {
 4004         struct vop_create_args *a = ap;
 4005 
 4006         if (!rc)
 4007                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4008 }
 4009 
 4010 void
 4011 vop_deleteextattr_post(void *ap, int rc)
 4012 {
 4013         struct vop_deleteextattr_args *a = ap;
 4014 
 4015         if (!rc)
 4016                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4017 }
 4018 
 4019 void
 4020 vop_link_post(void *ap, int rc)
 4021 {
 4022         struct vop_link_args *a = ap;
 4023 
 4024         if (!rc) {
 4025                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_LINK);
 4026                 VFS_KNOTE_LOCKED(a->a_tdvp, NOTE_WRITE);
 4027         }
 4028 }
 4029 
 4030 void
 4031 vop_mkdir_post(void *ap, int rc)
 4032 {
 4033         struct vop_mkdir_args *a = ap;
 4034 
 4035         if (!rc)
 4036                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4037 }
 4038 
 4039 void
 4040 vop_mknod_post(void *ap, int rc)
 4041 {
 4042         struct vop_mknod_args *a = ap;
 4043 
 4044         if (!rc)
 4045                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4046 }
 4047 
 4048 void
 4049 vop_remove_post(void *ap, int rc)
 4050 {
 4051         struct vop_remove_args *a = ap;
 4052 
 4053         if (!rc) {
 4054                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4055                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4056         }
 4057 }
 4058 
 4059 void
 4060 vop_rename_post(void *ap, int rc)
 4061 {
 4062         struct vop_rename_args *a = ap;
 4063 
 4064         if (!rc) {
 4065                 VFS_KNOTE_UNLOCKED(a->a_fdvp, NOTE_WRITE);
 4066                 VFS_KNOTE_UNLOCKED(a->a_tdvp, NOTE_WRITE);
 4067                 VFS_KNOTE_UNLOCKED(a->a_fvp, NOTE_RENAME);
 4068                 if (a->a_tvp)
 4069                         VFS_KNOTE_UNLOCKED(a->a_tvp, NOTE_DELETE);
 4070         }
 4071         if (a->a_tdvp != a->a_fdvp)
 4072                 vdrop(a->a_fdvp);
 4073         if (a->a_tvp != a->a_fvp)
 4074                 vdrop(a->a_fvp);
 4075         vdrop(a->a_tdvp);
 4076         if (a->a_tvp)
 4077                 vdrop(a->a_tvp);
 4078 }
 4079 
 4080 void
 4081 vop_rmdir_post(void *ap, int rc)
 4082 {
 4083         struct vop_rmdir_args *a = ap;
 4084 
 4085         if (!rc) {
 4086                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
 4087                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
 4088         }
 4089 }
 4090 
 4091 void
 4092 vop_setattr_post(void *ap, int rc)
 4093 {
 4094         struct vop_setattr_args *a = ap;
 4095 
 4096         if (!rc)
 4097                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4098 }
 4099 
 4100 void
 4101 vop_setextattr_post(void *ap, int rc)
 4102 {
 4103         struct vop_setextattr_args *a = ap;
 4104 
 4105         if (!rc)
 4106                 VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
 4107 }
 4108 
 4109 void
 4110 vop_symlink_post(void *ap, int rc)
 4111 {
 4112         struct vop_symlink_args *a = ap;
 4113 
 4114         if (!rc)
 4115                 VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 4116 }
 4117 
 4118 static struct knlist fs_knlist;
 4119 
 4120 static void
 4121 vfs_event_init(void *arg)
 4122 {
 4123         knlist_init_mtx(&fs_knlist, NULL);
 4124 }
 4125 /* XXX - correct order? */
 4126 SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
 4127 
 4128 void
 4129 vfs_event_signal(fsid_t *fsid, u_int32_t event, intptr_t data __unused)
 4130 {
 4131 
 4132         KNOTE_UNLOCKED(&fs_knlist, event);
 4133 }
 4134 
 4135 static int      filt_fsattach(struct knote *kn);
 4136 static void     filt_fsdetach(struct knote *kn);
 4137 static int      filt_fsevent(struct knote *kn, long hint);
 4138 
 4139 struct filterops fs_filtops =
 4140         { 0, filt_fsattach, filt_fsdetach, filt_fsevent };
 4141 
 4142 static int
 4143 filt_fsattach(struct knote *kn)
 4144 {
 4145 
 4146         kn->kn_flags |= EV_CLEAR;
 4147         knlist_add(&fs_knlist, kn, 0);
 4148         return (0);
 4149 }
 4150 
 4151 static void
 4152 filt_fsdetach(struct knote *kn)
 4153 {
 4154 
 4155         knlist_remove(&fs_knlist, kn, 0);
 4156 }
 4157 
 4158 static int
 4159 filt_fsevent(struct knote *kn, long hint)
 4160 {
 4161 
 4162         kn->kn_fflags |= hint;
 4163         return (kn->kn_fflags != 0);
 4164 }
 4165 
 4166 static int
 4167 sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
 4168 {
 4169         struct vfsidctl vc;
 4170         int error;
 4171         struct mount *mp;
 4172 
 4173         error = SYSCTL_IN(req, &vc, sizeof(vc));
 4174         if (error)
 4175                 return (error);
 4176         if (vc.vc_vers != VFS_CTL_VERS1)
 4177                 return (EINVAL);
 4178         mp = vfs_getvfs(&vc.vc_fsid);
 4179         if (mp == NULL)
 4180                 return (ENOENT);
 4181         /* ensure that a specific sysctl goes to the right filesystem. */
 4182         if (strcmp(vc.vc_fstypename, "*") != 0 &&
 4183             strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
 4184                 vfs_rel(mp);
 4185                 return (EINVAL);
 4186         }
 4187         VCTLTOREQ(&vc, req);
 4188         error = VFS_SYSCTL(mp, vc.vc_op, req);
 4189         vfs_rel(mp);
 4190         return (error);
 4191 }
 4192 
 4193 SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLFLAG_WR, NULL, 0, sysctl_vfs_ctl, "",
 4194     "Sysctl by fsid");
 4195 
 4196 /*
 4197  * Function to initialize a va_filerev field sensibly.
 4198  * XXX: Wouldn't a random number make a lot more sense ??
 4199  */
 4200 u_quad_t
 4201 init_va_filerev(void)
 4202 {
 4203         struct bintime bt;
 4204 
 4205         getbinuptime(&bt);
 4206         return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
 4207 }
 4208 
 4209 static int      filt_vfsread(struct knote *kn, long hint);
 4210 static int      filt_vfswrite(struct knote *kn, long hint);
 4211 static int      filt_vfsvnode(struct knote *kn, long hint);
 4212 static void     filt_vfsdetach(struct knote *kn);
 4213 static struct filterops vfsread_filtops =
 4214         { 1, NULL, filt_vfsdetach, filt_vfsread };
 4215 static struct filterops vfswrite_filtops =
 4216         { 1, NULL, filt_vfsdetach, filt_vfswrite };
 4217 static struct filterops vfsvnode_filtops =
 4218         { 1, NULL, filt_vfsdetach, filt_vfsvnode };
 4219 
 4220 static void
 4221 vfs_knllock(void *arg)
 4222 {
 4223         struct vnode *vp = arg;
 4224 
 4225         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 4226 }
 4227 
 4228 static void
 4229 vfs_knlunlock(void *arg)
 4230 {
 4231         struct vnode *vp = arg;
 4232 
 4233         VOP_UNLOCK(vp, 0);
 4234 }
 4235 
 4236 static void
 4237 vfs_knl_assert_locked(void *arg)
 4238 {
 4239 #ifdef DEBUG_VFS_LOCKS
 4240         struct vnode *vp = arg;
 4241 
 4242         ASSERT_VOP_LOCKED(vp, "vfs_knl_assert_locked");
 4243 #endif
 4244 }
 4245 
 4246 static void
 4247 vfs_knl_assert_unlocked(void *arg)
 4248 {
 4249 #ifdef DEBUG_VFS_LOCKS
 4250         struct vnode *vp = arg;
 4251 
 4252         ASSERT_VOP_UNLOCKED(vp, "vfs_knl_assert_unlocked");
 4253 #endif
 4254 }
 4255 
 4256 int
 4257 vfs_kqfilter(struct vop_kqfilter_args *ap)
 4258 {
 4259         struct vnode *vp = ap->a_vp;
 4260         struct knote *kn = ap->a_kn;
 4261         struct knlist *knl;
 4262 
 4263         switch (kn->kn_filter) {
 4264         case EVFILT_READ:
 4265                 kn->kn_fop = &vfsread_filtops;
 4266                 break;
 4267         case EVFILT_WRITE:
 4268                 kn->kn_fop = &vfswrite_filtops;
 4269                 break;
 4270         case EVFILT_VNODE:
 4271                 kn->kn_fop = &vfsvnode_filtops;
 4272                 break;
 4273         default:
 4274                 return (EINVAL);
 4275         }
 4276 
 4277         kn->kn_hook = (caddr_t)vp;
 4278 
 4279         v_addpollinfo(vp);
 4280         if (vp->v_pollinfo == NULL)
 4281                 return (ENOMEM);
 4282         knl = &vp->v_pollinfo->vpi_selinfo.si_note;
 4283         knlist_add(knl, kn, 0);
 4284 
 4285         return (0);
 4286 }
 4287 
 4288 /*
 4289  * Detach knote from vnode
 4290  */
 4291 static void
 4292 filt_vfsdetach(struct knote *kn)
 4293 {
 4294         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4295 
 4296         KASSERT(vp->v_pollinfo != NULL, ("Missing v_pollinfo"));
 4297         knlist_remove(&vp->v_pollinfo->vpi_selinfo.si_note, kn, 0);
 4298 }
 4299 
 4300 /*ARGSUSED*/
 4301 static int
 4302 filt_vfsread(struct knote *kn, long hint)
 4303 {
 4304         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4305         struct vattr va;
 4306         int res;
 4307 
 4308         /*
 4309          * filesystem is gone, so set the EOF flag and schedule
 4310          * the knote for deletion.
 4311          */
 4312         if (hint == NOTE_REVOKE) {
 4313                 VI_LOCK(vp);
 4314                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4315                 VI_UNLOCK(vp);
 4316                 return (1);
 4317         }
 4318 
 4319         if (VOP_GETATTR(vp, &va, curthread->td_ucred))
 4320                 return (0);
 4321 
 4322         VI_LOCK(vp);
 4323         kn->kn_data = va.va_size - kn->kn_fp->f_offset;
 4324         res = (kn->kn_data != 0);
 4325         VI_UNLOCK(vp);
 4326         return (res);
 4327 }
 4328 
 4329 /*ARGSUSED*/
 4330 static int
 4331 filt_vfswrite(struct knote *kn, long hint)
 4332 {
 4333         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4334 
 4335         VI_LOCK(vp);
 4336 
 4337         /*
 4338          * filesystem is gone, so set the EOF flag and schedule
 4339          * the knote for deletion.
 4340          */
 4341         if (hint == NOTE_REVOKE)
 4342                 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 4343 
 4344         kn->kn_data = 0;
 4345         VI_UNLOCK(vp);
 4346         return (1);
 4347 }
 4348 
 4349 static int
 4350 filt_vfsvnode(struct knote *kn, long hint)
 4351 {
 4352         struct vnode *vp = (struct vnode *)kn->kn_hook;
 4353         int res;
 4354 
 4355         VI_LOCK(vp);
 4356         if (kn->kn_sfflags & hint)
 4357                 kn->kn_fflags |= hint;
 4358         if (hint == NOTE_REVOKE) {
 4359                 kn->kn_flags |= EV_EOF;
 4360                 VI_UNLOCK(vp);
 4361                 return (1);
 4362         }
 4363         res = (kn->kn_fflags != 0);
 4364         VI_UNLOCK(vp);
 4365         return (res);
 4366 }
 4367 
 4368 int
 4369 vfs_read_dirent(struct vop_readdir_args *ap, struct dirent *dp, off_t off)
 4370 {
 4371         int error;
 4372 
 4373         if (dp->d_reclen > ap->a_uio->uio_resid)
 4374                 return (ENAMETOOLONG);
 4375         error = uiomove(dp, dp->d_reclen, ap->a_uio);
 4376         if (error) {
 4377                 if (ap->a_ncookies != NULL) {
 4378                         if (ap->a_cookies != NULL)
 4379                                 free(ap->a_cookies, M_TEMP);
 4380                         ap->a_cookies = NULL;
 4381                         *ap->a_ncookies = 0;
 4382                 }
 4383                 return (error);
 4384         }
 4385         if (ap->a_ncookies == NULL)
 4386                 return (0);
 4387 
 4388         KASSERT(ap->a_cookies,
 4389             ("NULL ap->a_cookies value with non-NULL ap->a_ncookies!"));
 4390 
 4391         *ap->a_cookies = realloc(*ap->a_cookies,
 4392             (*ap->a_ncookies + 1) * sizeof(u_long), M_TEMP, M_WAITOK | M_ZERO);
 4393         (*ap->a_cookies)[*ap->a_ncookies] = off;
 4394         return (0);
 4395 }
 4396 
 4397 /*
 4398  * Mark for update the access time of the file if the filesystem
 4399  * supports VOP_MARKATIME.  This functionality is used by execve and
 4400  * mmap, so we want to avoid the I/O implied by directly setting
 4401  * va_atime for the sake of efficiency.
 4402  */
 4403 void
 4404 vfs_mark_atime(struct vnode *vp, struct ucred *cred)
 4405 {
 4406         struct mount *mp;
 4407 
 4408         mp = vp->v_mount;
 4409         VFS_ASSERT_GIANT(mp);
 4410         ASSERT_VOP_LOCKED(vp, "vfs_mark_atime");
 4411         if (mp != NULL && (mp->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0)
 4412                 (void)VOP_MARKATIME(vp);
 4413 }
 4414 
 4415 /*
 4416  * The purpose of this routine is to remove granularity from accmode_t,
 4417  * reducing it into standard unix access bits - VEXEC, VREAD, VWRITE,
 4418  * VADMIN and VAPPEND.
 4419  *
 4420  * If it returns 0, the caller is supposed to continue with the usual
 4421  * access checks using 'accmode' as modified by this routine.  If it
 4422  * returns nonzero value, the caller is supposed to return that value
 4423  * as errno.
 4424  *
 4425  * Note that after this routine runs, accmode may be zero.
 4426  */
 4427 int
 4428 vfs_unixify_accmode(accmode_t *accmode)
 4429 {
 4430         /*
 4431          * There is no way to specify explicit "deny" rule using
 4432          * file mode or POSIX.1e ACLs.
 4433          */
 4434         if (*accmode & VEXPLICIT_DENY) {
 4435                 *accmode = 0;
 4436                 return (0);
 4437         }
 4438 
 4439         /*
 4440          * None of these can be translated into usual access bits.
 4441          * Also, the common case for NFSv4 ACLs is to not contain
 4442          * either of these bits. Caller should check for VWRITE
 4443          * on the containing directory instead.
 4444          */
 4445         if (*accmode & (VDELETE_CHILD | VDELETE))
 4446                 return (EPERM);
 4447 
 4448         if (*accmode & VADMIN_PERMS) {
 4449                 *accmode &= ~VADMIN_PERMS;
 4450                 *accmode |= VADMIN;
 4451         }
 4452 
 4453         /*
 4454          * There is no way to deny VREAD_ATTRIBUTES, VREAD_ACL
 4455          * or VSYNCHRONIZE using file mode or POSIX.1e ACL.
 4456          */
 4457         *accmode &= ~(VSTAT_PERMS | VSYNCHRONIZE);
 4458 
 4459         return (0);
 4460 }

Cache object: 4a2e0a9c25ab39a59625076f7405e682


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.