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

     /*      $OpenBSD: vfs_default.c,v 1.51 2022/04/27 14:52:25 claudio Exp $  */
     
     /*
      * Portions of this code are:
      *
      * Copyright (c) 1989, 1993
      *      The Regents of the University of California.  All rights reserved.
      * (c) UNIX System Laboratories, Inc.
      * All or some portions of this file are derived from material licensed
     * to the University of California by American Telephone and Telegraph
     * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     * the permission of UNIX System Laboratories, Inc.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/mount.h>
    #include <sys/vnode.h>
    #include <sys/namei.h>
    #include <sys/pool.h>
    #include <sys/event.h>
    #include <sys/specdev.h>
    
    int filt_generic_readwrite(struct knote *, long);
    void filt_generic_detach(struct knote *);
    
    /*
     * Eliminate all activity associated with the requested vnode
     * and with all vnodes aliased to the requested vnode.
     */
    int
    vop_generic_revoke(void *v)
    {
            struct vop_revoke_args *ap = v;
            struct vnode *vp, *vq;
            struct proc *p = curproc;
    
    #ifdef DIAGNOSTIC
            if ((ap->a_flags & REVOKEALL) == 0)
                    panic("vop_generic_revoke");
    #endif
    
            vp = ap->a_vp;
     
            while (vp->v_type == VBLK && vp->v_specinfo != NULL &&
                vp->v_specmountpoint != NULL) {
                    struct mount *mp = vp->v_specmountpoint;
    
                    /*
                     * If we have a mount point associated with the vnode, we must
                     * flush it out now, as to not leave a dangling zombie mount
                     * point laying around in VFS.
                     */
                    if (!vfs_busy(mp, VB_WRITE|VB_WAIT)) {
                            dounmount(mp, MNT_FORCE | MNT_DOOMED, p);
                            break;
                    }
            }
    
            if (vp->v_flag & VALIASED) {
                    /*
                     * If a vgone (or vclean) is already in progress,
                     * wait until it is done and return.
                     */
                    mtx_enter(&vnode_mtx);
                    if (vp->v_lflag & VXLOCK) {
                            vp->v_lflag |= VXWANT;
                            msleep_nsec(vp, &vnode_mtx, PINOD,
                                "vop_generic_revokeall", INFSLP);
                            mtx_leave(&vnode_mtx);
                            return(0);
                    }
    
                    /*
                     * Ensure that vp will not be vgone'd while we
                    * are eliminating its aliases.
                    */
                   vp->v_lflag |= VXLOCK;
                   mtx_leave(&vnode_mtx);
   
                   while (vp->v_flag & VALIASED) {
                           SLIST_FOREACH(vq, vp->v_hashchain, v_specnext) {
                                   if (vq->v_rdev != vp->v_rdev ||
                                       vq->v_type != vp->v_type || vp == vq)
                                           continue;
                                   vgonel(vq, p);
                                   break;
                           }
                   }
   
                   /*
                    * Remove the lock so that vgone below will
                    * really eliminate the vnode after which time
                    * vgone will awaken any sleepers.
                    */
                   mtx_enter(&vnode_mtx);
                   vp->v_lflag &= ~VXLOCK;
                   mtx_leave(&vnode_mtx);
           }
   
           vgonel(vp, p);
   
           return (0);
   }
   
   int
   vop_generic_badop(void *v)
   {
           panic("%s", __func__);
   }
   
   int
   vop_generic_bmap(void *v)
   {
           struct vop_bmap_args *ap = v;
   
           if (ap->a_vpp)
                   *ap->a_vpp = ap->a_vp;
           if (ap->a_bnp)
                   *ap->a_bnp = ap->a_bn;
           if (ap->a_runp)
                   *ap->a_runp = 0;
   
           return (0);
   }
   
   int
   vop_generic_bwrite(void *v)
   {
           struct vop_bwrite_args *ap = v;
   
           return (bwrite(ap->a_bp));
   }
   
   int
   vop_generic_abortop(void *v)
   {
           struct vop_abortop_args *ap = v;
    
           if ((ap->a_cnp->cn_flags & (HASBUF | SAVESTART)) == HASBUF)
                   pool_put(&namei_pool, ap->a_cnp->cn_pnbuf);
   
           return (0);
   }
   
   const struct filterops generic_filtops = {
           .f_flags        = FILTEROP_ISFD,
           .f_attach       = NULL,
           .f_detach       = filt_generic_detach,
           .f_event        = filt_generic_readwrite,
   };
   
   int
   vop_generic_kqfilter(void *v)
   {
           struct vop_kqfilter_args *ap = v;
           struct knote *kn = ap->a_kn;
   
           switch (kn->kn_filter) {
           case EVFILT_READ:
           case EVFILT_WRITE:
                   kn->kn_fop = &generic_filtops;
                   break;
           default:
                   return (EINVAL);
           }
   
           return (0);
   }
   
   /* Trivial lookup routine that always fails. */
   int
   vop_generic_lookup(void *v)
   {
           struct vop_lookup_args  *ap = v;
   
           *ap->a_vpp = NULL;
           return (ENOTDIR);
   }
   
   void
   filt_generic_detach(struct knote *kn)
   {
   }
   
   int
   filt_generic_readwrite(struct knote *kn, long hint)
   {
           /*
            * filesystem is gone, so set the EOF flag and schedule 
            * the knote for deletion.
            */
           if (hint == NOTE_REVOKE) {
                   kn->kn_flags |= (EV_EOF | EV_ONESHOT);
                   return (1);
           }
   
           kn->kn_data = 0;
   
           return (1);
   }

Cache object: 014494ef0d1e7220fd91a44cb70dd010