keep track of pending selects
[unix-history] / usr / src / sys / kern / vfs_subr.c
index 9458116..a679371 100644 (file)
@@ -14,7 +14,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- *     @(#)vfs_subr.c  7.14 (Berkeley) %G%
+ *     @(#)vfs_subr.c  7.46 (Berkeley) %G%
  */
 
 /*
  */
 
 /*
@@ -25,6 +25,7 @@
 #include "mount.h"
 #include "time.h"
 #include "vnode.h"
 #include "mount.h"
 #include "time.h"
 #include "vnode.h"
+#include "specdev.h"
 #include "namei.h"
 #include "ucred.h"
 #include "errno.h"
 #include "namei.h"
 #include "ucred.h"
 #include "errno.h"
@@ -41,9 +42,9 @@ vfs_remove(mp)
 
        if (mp == rootfs)
                panic("vfs_remove: unmounting root");
 
        if (mp == rootfs)
                panic("vfs_remove: unmounting root");
-       mp->m_prev->m_next = mp->m_next;
-       mp->m_next->m_prev = mp->m_prev;
-       mp->m_vnodecovered->v_mountedhere = (struct mount *)0;
+       mp->mnt_prev->mnt_next = mp->mnt_next;
+       mp->mnt_next->mnt_prev = mp->mnt_prev;
+       mp->mnt_vnodecovered->v_mountedhere = (struct mount *)0;
        vfs_unlock(mp);
 }
 
        vfs_unlock(mp);
 }
 
@@ -55,11 +56,11 @@ vfs_lock(mp)
        register struct mount *mp;
 {
 
        register struct mount *mp;
 {
 
-       while(mp->m_flag & M_MLOCK) {
-               mp->m_flag |= M_MWAIT;
+       while(mp->mnt_flag & MNT_MLOCK) {
+               mp->mnt_flag |= MNT_MWAIT;
                sleep((caddr_t)mp, PVFS);
        }
                sleep((caddr_t)mp, PVFS);
        }
-       mp->m_flag |= M_MLOCK;
+       mp->mnt_flag |= MNT_MLOCK;
        return (0);
 }
 
        return (0);
 }
 
@@ -72,15 +73,51 @@ vfs_unlock(mp)
        register struct mount *mp;
 {
 
        register struct mount *mp;
 {
 
-       if ((mp->m_flag & M_MLOCK) == 0)
-               panic("vfs_unlock: locked fs");
-       mp->m_flag &= ~M_MLOCK;
-       if (mp->m_flag & M_MWAIT) {
-               mp->m_flag &= ~M_MWAIT;
+       if ((mp->mnt_flag & MNT_MLOCK) == 0)
+               panic("vfs_unlock: not locked");
+       mp->mnt_flag &= ~MNT_MLOCK;
+       if (mp->mnt_flag & MNT_MWAIT) {
+               mp->mnt_flag &= ~MNT_MWAIT;
                wakeup((caddr_t)mp);
        }
 }
 
                wakeup((caddr_t)mp);
        }
 }
 
+/*
+ * Mark a mount point as busy.
+ * Used to synchronize access and to delay unmounting.
+ */
+vfs_busy(mp)
+       register struct mount *mp;
+{
+
+       while(mp->mnt_flag & MNT_MPBUSY) {
+               mp->mnt_flag |= MNT_MPWANT;
+               sleep((caddr_t)&mp->mnt_flag, PVFS);
+       }
+       if (mp->mnt_flag & MNT_UNMOUNT)
+               return (1);
+       mp->mnt_flag |= MNT_MPBUSY;
+       return (0);
+}
+
+/*
+ * Free a busy filesystem.
+ * Panic if filesystem is not busy.
+ */
+void
+vfs_unbusy(mp)
+       register struct mount *mp;
+{
+
+       if ((mp->mnt_flag & MNT_MPBUSY) == 0)
+               panic("vfs_unbusy: not busy");
+       mp->mnt_flag &= ~MNT_MPBUSY;
+       if (mp->mnt_flag & MNT_MPWANT) {
+               mp->mnt_flag &= ~MNT_MPWANT;
+               wakeup((caddr_t)&mp->mnt_flag);
+       }
+}
+
 /*
  * Lookup a mount point by filesystem identifier.
  */
 /*
  * Lookup a mount point by filesystem identifier.
  */
@@ -92,11 +129,11 @@ getvfs(fsid)
 
        mp = rootfs;
        do {
 
        mp = rootfs;
        do {
-               if (mp->m_fsid.val[0] == fsid->val[0] &&
-                   mp->m_fsid.val[1] == fsid->val[1]) {
+               if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
+                   mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
                        return (mp);
                }
                        return (mp);
                }
-               mp = mp->m_next;
+               mp = mp->mnt_next;
        } while (mp != rootfs);
        return ((struct mount *)0);
 }
        } while (mp != rootfs);
        return ((struct mount *)0);
 }
@@ -111,8 +148,8 @@ void vattr_null(vap)
        vap->va_type = VNON;
        vap->va_mode = vap->va_nlink = vap->va_uid = vap->va_gid =
                vap->va_fsid = vap->va_fileid = vap->va_size =
        vap->va_type = VNON;
        vap->va_mode = vap->va_nlink = vap->va_uid = vap->va_gid =
                vap->va_fsid = vap->va_fileid = vap->va_size =
-               vap->va_size1 = vap->va_blocksize = vap->va_rdev =
-               vap->va_bytes = vap->va_bytes1 =
+               vap->va_size_rsv = vap->va_blocksize = vap->va_rdev =
+               vap->va_bytes = vap->va_bytes_rsv =
                vap->va_atime.tv_sec = vap->va_atime.tv_usec =
                vap->va_mtime.tv_sec = vap->va_mtime.tv_usec =
                vap->va_ctime.tv_sec = vap->va_ctime.tv_usec =
                vap->va_atime.tv_sec = vap->va_atime.tv_usec =
                vap->va_mtime.tv_sec = vap->va_mtime.tv_usec =
                vap->va_ctime.tv_sec = vap->va_ctime.tv_usec =
@@ -131,7 +168,7 @@ ndinit(ndp)
        ndp->ni_iovcnt = 1;
        ndp->ni_base = (caddr_t)&ndp->ni_dent;
        ndp->ni_rw = UIO_WRITE;
        ndp->ni_iovcnt = 1;
        ndp->ni_base = (caddr_t)&ndp->ni_dent;
        ndp->ni_rw = UIO_WRITE;
-       ndp->ni_segflg = UIO_SYSSPACE;
+       ndp->ni_uioseg = UIO_SYSSPACE;
 }
 
 /*
 }
 
 /*
@@ -169,35 +206,17 @@ ndrele(ndp)
  */
 struct vnode *vfreeh, **vfreet;
 extern struct vnodeops dead_vnodeops, spec_vnodeops;
  */
 struct vnode *vfreeh, **vfreet;
 extern struct vnodeops dead_vnodeops, spec_vnodeops;
-struct speclist *speclisth;
-struct speclist {
-       struct speclist *sl_next;
-       struct vnode *sl_vp;
-};
+extern void vclean();
+long numvnodes;
+struct vattr va_null;
 
 /*
  * Initialize the vnode structures and initialize each file system type.
  */
 vfsinit()
 {
 
 /*
  * Initialize the vnode structures and initialize each file system type.
  */
 vfsinit()
 {
-       register struct vnode *vp = vnode;
        struct vfsops **vfsp;
 
        struct vfsops **vfsp;
 
-       /*
-        * Build vnode free list.
-        */
-       vfreeh = vp;
-       vfreet = &vp->v_freef;
-       vp->v_freeb = &vfreeh;
-       vp->v_op = &dead_vnodeops;
-       for (vp++; vp < vnodeNVNODE; vp++) {
-               *vfreet = vp;
-               vp->v_freeb = vfreet;
-               vfreet = &vp->v_freef;
-               vp->v_op = &dead_vnodeops;
-       }
-       vp--;
-       vp->v_freef = NULL;
        /*
         * Initialize the vnode name cache
         */
        /*
         * Initialize the vnode name cache
         */
@@ -205,6 +224,7 @@ vfsinit()
        /*
         * Initialize each file system type.
         */
        /*
         * Initialize each file system type.
         */
+       vattr_null(&va_null);
        for (vfsp = &vfssw[0]; vfsp <= &vfssw[MOUNT_MAXTYPE]; vfsp++) {
                if (*vfsp == NULL)
                        continue;
        for (vfsp = &vfssw[0]; vfsp <= &vfssw[MOUNT_MAXTYPE]; vfsp++) {
                if (*vfsp == NULL)
                        continue;
@@ -223,29 +243,37 @@ getnewvnode(tag, mp, vops, vpp)
 {
        register struct vnode *vp, *vq;
 
 {
        register struct vnode *vp, *vq;
 
-       if ((vp = vfreeh) == NULL) {
-               tablefull("vnode");
-               *vpp = 0;
-               return (ENFILE);
+       if (numvnodes < desiredvnodes) {
+               vp = (struct vnode *)malloc(sizeof *vp, M_VNODE, M_WAITOK);
+               bzero((char *)vp, sizeof *vp);
+               numvnodes++;
+       } else {
+               if ((vp = vfreeh) == NULL) {
+                       tablefull("vnode");
+                       *vpp = 0;
+                       return (ENFILE);
+               }
+               if (vp->v_usecount)
+                       panic("free vnode isn't");
+               if (vq = vp->v_freef)
+                       vq->v_freeb = &vfreeh;
+               else
+                       vfreet = &vfreeh;
+               vfreeh = vq;
+               vp->v_freef = NULL;
+               vp->v_freeb = NULL;
+               if (vp->v_type != VBAD)
+                       vgone(vp);
+               vp->v_flag = 0;
+               vp->v_shlockc = 0;
+               vp->v_exlockc = 0;
+               vp->v_lastr = 0;
+               vp->v_socket = 0;
        }
        }
-       if (vp->v_count)
-               panic("free vnode isn't");
-       if (vq = vp->v_freef)
-               vq->v_freeb = &vfreeh;
-       vfreeh = vq;
-       vp->v_freef = NULL;
-       vp->v_freeb = NULL;
-       if (vp->v_type != VNON && vp->v_type != VBAD)
-               vgone(vp);
        vp->v_type = VNON;
        vp->v_type = VNON;
-       vp->v_flag = 0;
-       vp->v_shlockc = 0;
-       vp->v_exlockc = 0;
-       vp->v_socket = 0;
        cache_purge(vp);
        vp->v_tag = tag;
        vp->v_op = vops;
        cache_purge(vp);
        vp->v_tag = tag;
        vp->v_op = vops;
-       vp->v_mount = mp;
        insmntque(vp, mp);
        VREF(vp);
        *vpp = vp;
        insmntque(vp, mp);
        VREF(vp);
        *vpp = vp;
@@ -272,19 +300,20 @@ insmntque(vp, mp)
        /*
         * Insert into list of vnodes for the new mount point, if available.
         */
        /*
         * Insert into list of vnodes for the new mount point, if available.
         */
+       vp->v_mount = mp;
        if (mp == NULL) {
                vp->v_mountf = NULL;
                vp->v_mountb = NULL;
                return;
        }
        if (mp == NULL) {
                vp->v_mountf = NULL;
                vp->v_mountb = NULL;
                return;
        }
-       if (mp->m_mounth) {
-               vp->v_mountf = mp->m_mounth;
-               vp->v_mountb = &mp->m_mounth;
-               mp->m_mounth->v_mountb = &vp->v_mountf;
-               mp->m_mounth = vp;
+       if (mp->mnt_mounth) {
+               vp->v_mountf = mp->mnt_mounth;
+               vp->v_mountb = &mp->mnt_mounth;
+               mp->mnt_mounth->v_mountb = &vp->v_mountf;
+               mp->mnt_mounth = vp;
        } else {
        } else {
-               mp->m_mounth = vp;
-               vp->v_mountb = &mp->m_mounth;
+               mp->mnt_mounth = vp;
+               vp->v_mountb = &mp->mnt_mounth;
                vp->v_mountf = NULL;
        }
 }
                vp->v_mountf = NULL;
        }
 }
@@ -309,8 +338,7 @@ bdevvp(dev, vpp)
        }
        vp = nvp;
        vp->v_type = VBLK;
        }
        vp = nvp;
        vp->v_type = VBLK;
-       vp->v_rdev = dev;
-       if (nvp = checkalias(vp, (struct mount *)0)) {
+       if (nvp = checkalias(vp, dev, (struct mount *)0)) {
                vput(vp);
                vp = nvp;
        }
                vput(vp);
                vp = nvp;
        }
@@ -327,31 +355,47 @@ bdevvp(dev, vpp)
  * caller is responsible for filling it with its new contents.
  */
 struct vnode *
  * caller is responsible for filling it with its new contents.
  */
 struct vnode *
-checkalias(nvp, mp)
+checkalias(nvp, nvp_rdev, mp)
        register struct vnode *nvp;
        register struct vnode *nvp;
+       dev_t nvp_rdev;
        struct mount *mp;
 {
        register struct vnode *vp;
        struct mount *mp;
 {
        register struct vnode *vp;
-       register struct speclist *slp;
+       struct vnode **vpp;
 
        if (nvp->v_type != VBLK && nvp->v_type != VCHR)
 
        if (nvp->v_type != VBLK && nvp->v_type != VCHR)
-               return ((struct vnode *)0);
+               return (NULLVP);
+
+       vpp = &speclisth[SPECHASH(nvp_rdev)];
 loop:
 loop:
-       for (slp = speclisth; slp; slp = slp->sl_next) {
-               vp = slp->sl_vp;
-               if (nvp->v_rdev != vp->v_rdev ||
-                   nvp->v_type != vp->v_type)
+       for (vp = *vpp; vp; vp = vp->v_specnext) {
+               if (nvp_rdev != vp->v_rdev || nvp->v_type != vp->v_type)
                        continue;
                        continue;
+               /*
+                * Alias, but not in use, so flush it out.
+                */
+               if (vp->v_usecount == 0) {
+                       vgone(vp);
+                       goto loop;
+               }
                if (vget(vp))
                        goto loop;
                break;
        }
                if (vget(vp))
                        goto loop;
                break;
        }
-       if (slp == NULL) {
-               MALLOC(slp, struct speclist *, sizeof(*slp), M_VNODE, M_WAITOK);
-               slp->sl_vp = nvp;
-               slp->sl_next = speclisth;
-               speclisth = slp;
-               return ((struct vnode *)0);
+       if (vp == NULL || vp->v_tag != VT_NON) {
+               MALLOC(nvp->v_specinfo, struct specinfo *,
+                       sizeof(struct specinfo), M_VNODE, M_WAITOK);
+               nvp->v_rdev = nvp_rdev;
+               nvp->v_hashchain = vpp;
+               nvp->v_specnext = *vpp;
+               nvp->v_specflags = 0;
+               *vpp = nvp;
+               if (vp != NULL) {
+                       nvp->v_flag |= VALIASED;
+                       vp->v_flag |= VALIASED;
+                       vput(vp);
+               }
+               return (NULLVP);
        }
        VOP_UNLOCK(vp);
        vclean(vp, 0);
        }
        VOP_UNLOCK(vp);
        vclean(vp, 0);
@@ -380,7 +424,7 @@ vget(vp)
                sleep((caddr_t)vp, PINOD);
                return (1);
        }
                sleep((caddr_t)vp, PINOD);
                return (1);
        }
-       if (vp->v_count == 0) {
+       if (vp->v_usecount == 0) {
                if (vq = vp->v_freef)
                        vq->v_freeb = vp->v_freeb;
                else
                if (vq = vp->v_freef)
                        vq->v_freeb = vp->v_freeb;
                else
@@ -401,7 +445,7 @@ void vref(vp)
        struct vnode *vp;
 {
 
        struct vnode *vp;
 {
 
-       vp->v_count++;
+       vp->v_usecount++;
 }
 
 /*
 }
 
 /*
@@ -424,13 +468,12 @@ void vrele(vp)
 
        if (vp == NULL)
                panic("vrele: null vp");
 
        if (vp == NULL)
                panic("vrele: null vp");
-       vp->v_count--;
-       if (vp->v_count < 0)
-               printf("vnode bad ref count %d, type %d, tag %d\n",
-                       vp->v_count, vp->v_type, vp->v_tag);
-       if (vp->v_count > 0)
+       vp->v_usecount--;
+       if (vp->v_usecount < 0)
+               vprint("vrele: bad ref count", vp);
+       if (vp->v_usecount > 0)
                return;
                return;
-       if (vfreeh == (struct vnode *)0) {
+       if (vfreeh == NULLVP) {
                /*
                 * insert into empty list
                 */
                /*
                 * insert into empty list
                 */
@@ -448,6 +491,28 @@ void vrele(vp)
        VOP_INACTIVE(vp);
 }
 
        VOP_INACTIVE(vp);
 }
 
+/*
+ * Page or buffer structure gets a reference.
+ */
+vhold(vp)
+       register struct vnode *vp;
+{
+
+       vp->v_holdcnt++;
+}
+
+/*
+ * Page or buffer structure frees a reference.
+ */
+holdrele(vp)
+       register struct vnode *vp;
+{
+
+       if (vp->v_holdcnt <= 0)
+               panic("holdrele: holdcnt");
+       vp->v_holdcnt--;
+}
+
 /*
  * Remove any vnodes in the vnode table belonging to mount point mp.
  *
 /*
  * Remove any vnodes in the vnode table belonging to mount point mp.
  *
@@ -466,19 +531,28 @@ vflush(mp, skipvp, flags)
        register struct vnode *vp, *nvp;
        int busy = 0;
 
        register struct vnode *vp, *nvp;
        int busy = 0;
 
-       for (vp = mp->m_mounth; vp; vp = nvp) {
+       if ((mp->mnt_flag & MNT_MPBUSY) == 0)
+               panic("vflush: not busy");
+loop:
+       for (vp = mp->mnt_mounth; vp; vp = nvp) {
+               if (vp->v_mount != mp)
+                       goto loop;
                nvp = vp->v_mountf;
                /*
                 * Skip over a selected vnode.
                nvp = vp->v_mountf;
                /*
                 * Skip over a selected vnode.
-                * Used by ufs to skip over the quota structure inode.
                 */
                if (vp == skipvp)
                        continue;
                /*
                 */
                if (vp == skipvp)
                        continue;
                /*
-                * With v_count == 0, all we need to do is clear
+                * Skip over a vnodes marked VSYSTEM.
+                */
+               if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM))
+                       continue;
+               /*
+                * With v_usecount == 0, all we need to do is clear
                 * out the vnode data structures and we are done.
                 */
                 * out the vnode data structures and we are done.
                 */
-               if (vp->v_count == 0) {
+               if (vp->v_usecount == 0) {
                        vgone(vp);
                        continue;
                }
                        vgone(vp);
                        continue;
                }
@@ -486,7 +560,7 @@ vflush(mp, skipvp, flags)
                 * For block or character devices, revert to an
                 * anonymous device. For all other files, just kill them.
                 */
                 * For block or character devices, revert to an
                 * anonymous device. For all other files, just kill them.
                 */
-               if (flags & MNT_FORCE) {
+               if (flags & FORCECLOSE) {
                        if (vp->v_type != VBLK && vp->v_type != VCHR) {
                                vgone(vp);
                        } else {
                        if (vp->v_type != VBLK && vp->v_type != VCHR) {
                                vgone(vp);
                        } else {
@@ -497,8 +571,7 @@ vflush(mp, skipvp, flags)
                        continue;
                }
                if (busyprt)
                        continue;
                }
                if (busyprt)
-                       printf("vflush: busy vnode count %d type %d tag %d\n",
-                           vp->v_count, vp->v_type, vp->v_tag);
+                       vprint("vflush: busy vnode", vp);
                busy++;
        }
        if (busy)
                busy++;
        }
        if (busy)
@@ -509,30 +582,38 @@ vflush(mp, skipvp, flags)
 /*
  * Disassociate the underlying file system from a vnode.
  */
 /*
  * Disassociate the underlying file system from a vnode.
  */
-void vclean(vp, doclose)
+void vclean(vp, flags)
        register struct vnode *vp;
        register struct vnode *vp;
-       long doclose;
+       long flags;
 {
        struct vnodeops *origops;
        int active;
 
        /*
         * Check to see if the vnode is in use.
 {
        struct vnodeops *origops;
        int active;
 
        /*
         * Check to see if the vnode is in use.
-        * If so we have to lock it before we clean it out.
+        * If so we have to reference it before we clean it out
+        * so that its count cannot fall to zero and generate a
+        * race against ourselves to recycle it.
         */
         */
-       if (active = vp->v_count) {
+       if (active = vp->v_usecount)
                VREF(vp);
                VREF(vp);
-               VOP_LOCK(vp);
-       }
        /*
         * Prevent the vnode from being recycled or
         * brought into use while we clean it out.
         */
        /*
         * Prevent the vnode from being recycled or
         * brought into use while we clean it out.
         */
-       while (vp->v_flag & VXLOCK) {
-               vp->v_flag |= VXWANT;
-               sleep((caddr_t)vp, PINOD);
-       }
+       if (vp->v_flag & VXLOCK)
+               panic("vclean: deadlock");
        vp->v_flag |= VXLOCK;
        vp->v_flag |= VXLOCK;
+       /*
+        * Even if the count is zero, the VOP_INACTIVE routine may still
+        * have the object locked while it cleans it out. The VOP_LOCK
+        * ensures that the VOP_INACTIVE routine is done with its work.
+        * For active vnodes, it ensures that no other activity can
+        * occur while the buffer list is being cleaned out.
+        */
+       VOP_LOCK(vp);
+       if (flags & DOCLOSE)
+               vinvalbuf(vp, 1);
        /*
         * Prevent any further operations on the vnode from
         * being passed through to the old file system.
        /*
         * Prevent any further operations on the vnode from
         * being passed through to the old file system.
@@ -544,9 +625,9 @@ void vclean(vp, doclose)
         * If purging an active vnode, it must be unlocked, closed,
         * and deactivated before being reclaimed.
         */
         * If purging an active vnode, it must be unlocked, closed,
         * and deactivated before being reclaimed.
         */
+       (*(origops->vn_unlock))(vp);
        if (active) {
        if (active) {
-               (*(origops->vn_unlock))(vp);
-               if (doclose)
+               if (flags & DOCLOSE)
                        (*(origops->vn_close))(vp, 0, NOCRED);
                (*(origops->vn_inactive))(vp);
        }
                        (*(origops->vn_close))(vp, 0, NOCRED);
                (*(origops->vn_inactive))(vp);
        }
@@ -567,6 +648,49 @@ void vclean(vp, doclose)
        }
 }
 
        }
 }
 
+/*
+ * Eliminate all activity associated with  the requested vnode
+ * and with all vnodes aliased to the requested vnode.
+ */
+void vgoneall(vp)
+       register struct vnode *vp;
+{
+       register struct vnode *vq;
+
+       if (vp->v_flag & VALIASED) {
+               /*
+                * If a vgone (or vclean) is already in progress,
+                * wait until it is done and return.
+                */
+               if (vp->v_flag & VXLOCK) {
+                       vp->v_flag |= VXWANT;
+                       sleep((caddr_t)vp, PINOD);
+                       return;
+               }
+               /*
+                * Ensure that vp will not be vgone'd while we
+                * are eliminating its aliases.
+                */
+               vp->v_flag |= VXLOCK;
+               while (vp->v_flag & VALIASED) {
+                       for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
+                               if (vq->v_rdev != vp->v_rdev ||
+                                   vq->v_type != vp->v_type || vp == vq)
+                                       continue;
+                               vgone(vq);
+                               break;
+                       }
+               }
+               /*
+                * Remove the lock so that vgone below will
+                * really eliminate the vnode after which time
+                * vgone will awaken any sleepers.
+                */
+               vp->v_flag &= ~VXLOCK;
+       }
+       vgone(vp);
+}
+
 /*
  * Eliminate all activity associated with a vnode
  * in preparation for reuse.
 /*
  * Eliminate all activity associated with a vnode
  * in preparation for reuse.
@@ -574,14 +698,23 @@ void vclean(vp, doclose)
 void vgone(vp)
        register struct vnode *vp;
 {
 void vgone(vp)
        register struct vnode *vp;
 {
-       register struct speclist *slp;
-       struct speclist *pslp;
        register struct vnode *vq;
        register struct vnode *vq;
+       struct vnode *vx;
+       long count;
 
 
+       /*
+        * If a vgone (or vclean) is already in progress,
+        * wait until it is done and return.
+        */
+       if (vp->v_flag & VXLOCK) {
+               vp->v_flag |= VXWANT;
+               sleep((caddr_t)vp, PINOD);
+               return;
+       }
        /*
         * Clean out the filesystem specific data.
         */
        /*
         * Clean out the filesystem specific data.
         */
-       vclean(vp, 1);
+       vclean(vp, DOCLOSE);
        /*
         * Delete from old mount point vnode list, if on one.
         */
        /*
         * Delete from old mount point vnode list, if on one.
         */
@@ -596,21 +729,35 @@ void vgone(vp)
         * If special device, remove it from special device alias list.
         */
        if (vp->v_type == VBLK || vp->v_type == VCHR) {
         * If special device, remove it from special device alias list.
         */
        if (vp->v_type == VBLK || vp->v_type == VCHR) {
-               if (speclisth->sl_vp == vp) {
-                       slp = speclisth;
-                       speclisth = slp->sl_next;
+               if (*vp->v_hashchain == vp) {
+                       *vp->v_hashchain = vp->v_specnext;
                } else {
                } else {
-                       for (pslp = speclisth, slp = pslp->sl_next; slp;
-                            pslp = slp, slp = slp->sl_next) {
-                               if (slp->sl_vp != vp)
+                       for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
+                               if (vq->v_specnext != vp)
                                        continue;
                                        continue;
-                               pslp->sl_next = slp->sl_next;
+                               vq->v_specnext = vp->v_specnext;
                                break;
                        }
                                break;
                        }
-                       if (slp == NULL)
+                       if (vq == NULL)
                                panic("missing bdev");
                }
                                panic("missing bdev");
                }
-               FREE(slp, M_VNODE);
+               if (vp->v_flag & VALIASED) {
+                       count = 0;
+                       for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
+                               if (vq->v_rdev != vp->v_rdev ||
+                                   vq->v_type != vp->v_type)
+                                       continue;
+                               count++;
+                               vx = vq;
+                       }
+                       if (count == 0)
+                               panic("missing alias");
+                       if (count == 1)
+                               vx->v_flag &= ~VALIASED;
+                       vp->v_flag &= ~VALIASED;
+               }
+               FREE(vp->v_specinfo, M_VNODE);
+               vp->v_specinfo = NULL;
        }
        /*
         * If it is on the freelist, move it to the head of the list.
        }
        /*
         * If it is on the freelist, move it to the head of the list.
@@ -628,3 +775,157 @@ void vgone(vp)
        }
        vp->v_type = VBAD;
 }
        }
        vp->v_type = VBAD;
 }
+
+/*
+ * Lookup a vnode by device number.
+ */
+vfinddev(dev, type, vpp)
+       dev_t dev;
+       enum vtype type;
+       struct vnode **vpp;
+{
+       register struct vnode *vp;
+
+       for (vp = speclisth[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
+               if (dev != vp->v_rdev || type != vp->v_type)
+                       continue;
+               *vpp = vp;
+               return (0);
+       }
+       return (1);
+}
+
+/*
+ * Calculate the total number of references to a special device.
+ */
+vcount(vp)
+       register struct vnode *vp;
+{
+       register struct vnode *vq;
+       int count;
+
+       if ((vp->v_flag & VALIASED) == 0)
+               return (vp->v_usecount);
+loop:
+       for (count = 0, vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
+               if (vq->v_rdev != vp->v_rdev || vq->v_type != vp->v_type)
+                       continue;
+               /*
+                * Alias, but not in use, so flush it out.
+                */
+               if (vq->v_usecount == 0) {
+                       vgone(vq);
+                       goto loop;
+               }
+               count += vq->v_usecount;
+       }
+       return (count);
+}
+
+/*
+ * Print out a description of a vnode.
+ */
+static char *typename[] =
+   { "VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD" };
+
+vprint(label, vp)
+       char *label;
+       register struct vnode *vp;
+{
+       char buf[64];
+
+       if (label != NULL)
+               printf("%s: ", label);
+       printf("type %s, usecount %d, refcount %d,", typename[vp->v_type],
+               vp->v_usecount, vp->v_holdcnt);
+       buf[0] = '\0';
+       if (vp->v_flag & VROOT)
+               strcat(buf, "|VROOT");
+       if (vp->v_flag & VTEXT)
+               strcat(buf, "|VTEXT");
+       if (vp->v_flag & VSYSTEM)
+               strcat(buf, "|VSYSTEM");
+       if (vp->v_flag & VEXLOCK)
+               strcat(buf, "|VEXLOCK");
+       if (vp->v_flag & VSHLOCK)
+               strcat(buf, "|VSHLOCK");
+       if (vp->v_flag & VLWAIT)
+               strcat(buf, "|VLWAIT");
+       if (vp->v_flag & VXLOCK)
+               strcat(buf, "|VXLOCK");
+       if (vp->v_flag & VXWANT)
+               strcat(buf, "|VXWANT");
+       if (vp->v_flag & VBWAIT)
+               strcat(buf, "|VBWAIT");
+       if (vp->v_flag & VALIASED)
+               strcat(buf, "|VALIASED");
+       if (buf[0] != '\0')
+               printf(" flags (%s)", &buf[1]);
+       printf("\n\t");
+       VOP_PRINT(vp);
+}
+
+int kinfo_vdebug = 1;
+int kinfo_vgetfailed;
+#define KINFO_VNODESLOP        10
+/*
+ * Dump vnode list (via kinfo).
+ * Copyout address of vnode followed by vnode.
+ */
+kinfo_vnode(op, where, acopysize, arg, aneeded)
+       char *where;
+       int *acopysize, *aneeded;
+{
+       register struct mount *mp = rootfs;
+       struct mount *omp;
+       struct vnode *vp;
+       register needed = 0;
+       register char *bp = where, *savebp;
+       char *ewhere = where + *acopysize;
+       int error;
+
+#define VPTRSZ sizeof (struct vnode *)
+#define VNODESZ        sizeof (struct vnode)
+       if (where == NULL) {
+               *aneeded = (numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ);
+               return (0);
+       }
+               
+       do {
+               if (vfs_busy(mp)) {
+                       mp = mp->mnt_next;
+                       continue;
+               }
+               savebp = bp;
+again:
+               for (vp = mp->mnt_mounth; vp; vp = vp->v_mountf) {
+                       /*
+                        * Check that the vp is still associated with
+                        * this filesystem.  RACE: could have been
+                        * recycled onto the same filesystem.
+                        */
+                       if (vp->v_mount != mp) {
+                               if (kinfo_vdebug)
+                                       printf("kinfo: vp changed\n");
+                               bp = savebp;
+                               goto again;
+                       }
+                       if ((bp + VPTRSZ + VNODESZ <= ewhere) && 
+                           ((error = copyout((caddr_t)&vp, bp, VPTRSZ)) ||
+                            (error = copyout((caddr_t)vp, bp + VPTRSZ, 
+                             VNODESZ))))
+                               return (error);
+                       bp += VPTRSZ + VNODESZ;
+               }
+               omp = mp;
+               mp = mp->mnt_next;
+               vfs_unbusy(omp);
+       } while (mp != rootfs);
+
+       *aneeded = bp - where;
+       if (bp > ewhere)
+               *acopysize = ewhere - where;
+       else
+               *acopysize = bp - where;
+       return (0);
+}