FreeBSD/Linux Kernel Cross Reference
sys/ufs/mfs/mfs_vnops.c

     /*
      * Copyright (c) 1989, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * 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. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. 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.
     *
     *      @(#)mfs_vnops.c 8.11 (Berkeley) 5/22/95
     * $FreeBSD$
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/proc.h>
    #include <sys/buf.h>
    #include <sys/vnode.h>
    #include <sys/malloc.h>
    #include <sys/sysproto.h>
    #include <sys/mman.h>
    #include <sys/conf.h>
    
    #include <ufs/mfs/mfsnode.h>
    #include <ufs/mfs/mfs_extern.h>
    
    static int      mfs_badop __P((struct vop_generic_args *));
    static int      mfs_bmap __P((struct vop_bmap_args *));
    static int      mfs_close __P((struct vop_close_args *));
    static int      mfs_fsync __P((struct vop_fsync_args *));
    static int      mfs_freeblks __P((struct vop_freeblks_args *));
    static int      mfs_inactive __P((struct vop_inactive_args *)); /* XXX */
    static int      mfs_open __P((struct vop_open_args *));
    static int      mfs_reclaim __P((struct vop_reclaim_args *)); /* XXX */
    static int      mfs_print __P((struct vop_print_args *)); /* XXX */
    static int      mfs_strategy __P((struct vop_strategy_args *)); /* XXX */
    static int      mfs_getpages __P((struct vop_getpages_args *)); /* XXX */
    /*
     * mfs vnode operations.
     */
    vop_t **mfs_vnodeop_p;
    static struct vnodeopv_entry_desc mfs_vnodeop_entries[] = {
            { &vop_default_desc,            (vop_t *) mfs_badop },
            { &vop_bmap_desc,               (vop_t *) mfs_bmap },
            { &vop_bwrite_desc,             (vop_t *) vop_defaultop },
            { &vop_close_desc,              (vop_t *) mfs_close },
            { &vop_createvobject_desc,      (vop_t *) vop_stdcreatevobject },
            { &vop_destroyvobject_desc,     (vop_t *) vop_stddestroyvobject },
            { &vop_freeblks_desc,           (vop_t *) mfs_freeblks },
            { &vop_fsync_desc,              (vop_t *) mfs_fsync },
            { &vop_getpages_desc,           (vop_t *) mfs_getpages },
            { &vop_getvobject_desc,         (vop_t *) vop_stdgetvobject },
            { &vop_inactive_desc,           (vop_t *) mfs_inactive },
            { &vop_ioctl_desc,              (vop_t *) vop_enotty },
            { &vop_islocked_desc,           (vop_t *) vop_defaultop },
            { &vop_lock_desc,               (vop_t *) vop_defaultop },
            { &vop_open_desc,               (vop_t *) mfs_open },
            { &vop_print_desc,              (vop_t *) mfs_print },
            { &vop_reclaim_desc,            (vop_t *) mfs_reclaim },
            { &vop_strategy_desc,           (vop_t *) mfs_strategy },
            { &vop_unlock_desc,             (vop_t *) vop_defaultop },
            { NULL, NULL }
    };
    static struct vnodeopv_desc mfs_vnodeop_opv_desc =
            { &mfs_vnodeop_p, mfs_vnodeop_entries };
    
    VNODEOP_SET(mfs_vnodeop_opv_desc);
    
    /*
     * Vnode Operations.
     *
     * Open called to allow memory filesystem to initialize and
     * validate before actual IO. Record our process identifier
     * so we can tell when we are doing I/O to ourself.
     */
   /* ARGSUSED */
   static int
   mfs_open(ap)
           struct vop_open_args /* {
                   struct vnode *a_vp;
                   int  a_mode;
                   struct ucred *a_cred;
                   struct proc *a_p;
           } */ *ap;
   {
   
           if (ap->a_vp->v_type != VBLK) {
                   panic("mfs_open not VBLK");
                   /* NOTREACHED */
           }
           return (0);
   }
   
   static int
   mfs_fsync(ap)
           struct vop_fsync_args *ap;
   {
   
           return (VOCALL(spec_vnodeop_p, VOFFSET(vop_fsync), ap));
   }
   
   /*
    * mfs_freeblks() - hook to allow us to free physical memory.
    *
    *      We implement the B_FREEBUF strategy.  We can't just madvise()
    *      here because we have to do it in the correct order vs other bio
    *      requests, so we queue it.
    *
    *      Note: geteblk() sets B_INVAL.  We leave it set to guarentee buffer
    *      throw-away on brelse()? XXX
    */
   
   static int
   mfs_freeblks(ap)
           struct vop_freeblks_args /* {   
                   struct vnode *a_vp;     
                   daddr_t a_addr;         
                   daddr_t a_length;       
           } */ *ap;
   {       
           struct buf *bp;
           struct vnode *vp;
   
           if (!vfinddev(ap->a_vp->v_rdev, VBLK, &vp) || vp->v_usecount == 0)
                   panic("mfs_freeblks: bad dev");
   
           bp = geteblk(ap->a_length);
           bp->b_flags |= B_FREEBUF | B_ASYNC;
           bp->b_dev = ap->a_vp->v_rdev;
           bp->b_blkno = ap->a_addr;
           bp->b_offset = dbtob(ap->a_addr);
           bp->b_bcount = ap->a_length;
           BUF_KERNPROC(bp);
           VOP_STRATEGY(vp, bp);
           return(0);
   }
   
   /*
    * Pass I/O requests to the memory filesystem process.
    */
   static int
   mfs_strategy(ap)
           struct vop_strategy_args /* {
                   struct vnode *a_vp;
                   struct buf *a_bp;
           } */ *ap;
   {
           register struct buf *bp = ap->a_bp;
           register struct mfsnode *mfsp;
           struct vnode *vp;
           struct proc *p = curproc;               /* XXX */
           int s;
   
           if (!vfinddev(bp->b_dev, VBLK, &vp) || vp->v_usecount == 0)
                   panic("mfs_strategy: bad dev");
           mfsp = VTOMFS(vp);
   
           /*
            * splbio required for queueing/dequeueing, in case of forwarded
            * BPs from bio interrupts (?).  It may not be necessary.
            */
   
           s = splbio();
   
           if (mfsp->mfs_pid == 0) {
                   /*
                    * mini-root.  Note: B_FREEBUF not supported at the moment,
                    * I'm not sure what kind of dataspace b_data is in.
                    */
                   caddr_t base;
   
                   base = mfsp->mfs_baseoff + (bp->b_blkno << DEV_BSHIFT);
                   if (bp->b_flags & B_FREEBUF)
                           ;
                   if (bp->b_flags & B_READ)
                           bcopy(base, bp->b_data, bp->b_bcount);
                   else
                           bcopy(bp->b_data, base, bp->b_bcount);
                   biodone(bp);
           } else if (mfsp->mfs_pid == p->p_pid) {
                   /*
                    * VOP to self
                    */
                   splx(s);
                   mfs_doio(bp, mfsp);
                   s = splbio();
           } else {
                   /*
                    * VOP from some other process, queue to MFS process and
                    * wake it up.
                    */
                   bufq_insert_tail(&mfsp->buf_queue, bp);
                   wakeup((caddr_t)vp);
           }
           splx(s);
           return (0);
   }
   
   /*
    * Memory file system I/O.
    *
    * Trivial on the HP since buffer has already been mapping into KVA space.
    *
    * Read and Write are handled with a simple copyin and copyout.    
    *
    * We also partially support VOP_FREEBLKS() via B_FREEBUF.  We can't implement
    * completely -- for example, on fragments or inode metadata, but we can
    * implement it for page-aligned requests.
    */
   void
   mfs_doio(bp, mfsp)
           register struct buf *bp;
           struct mfsnode *mfsp;
   {
           caddr_t base = mfsp->mfs_baseoff + (bp->b_blkno << DEV_BSHIFT);
   
           if (bp->b_flags & B_FREEBUF) {
                   /*
                    * Implement B_FREEBUF, which allows the filesystem to tell
                    * a block device when blocks are no longer needed (like when
                    * a file is deleted).  We use the hook to MADV_FREE the VM.
                    * This makes an MFS filesystem work as well or better then
                    * a sun-style swap-mounted filesystem.
                    */
                   int bytes = bp->b_bcount;
   
                   if ((vm_offset_t)base & PAGE_MASK) {
                           int n = PAGE_SIZE - ((vm_offset_t)base & PAGE_MASK);
                           bytes -= n;
                           base += n;
                   }
                   if (bytes > 0) {
                           struct madvise_args uap;
   
                           bytes &= ~PAGE_MASK;
                           if (bytes != 0) {
                                   bzero(&uap, sizeof(uap));
                                   uap.addr  = base;
                                   uap.len   = bytes;
                                   uap.behav = MADV_FREE;
                                   madvise(curproc, &uap);
                           }
                   }
                   bp->b_error = 0;
           } else if (bp->b_flags & B_READ) {
                   /*
                    * Read data from our 'memory' disk
                    */
                   bp->b_error = copyin(base, bp->b_data, bp->b_bcount);
           } else {
                   /*
                    * Write data to our 'memory' disk
                    */
                   bp->b_error = copyout(bp->b_data, base, bp->b_bcount);
           }
           if (bp->b_error)
                   bp->b_flags |= B_ERROR;
           biodone(bp);
   }
   
   /*
    * This is a noop, simply returning what one has been given.
    */
   static int
   mfs_bmap(ap)
           struct vop_bmap_args /* {
                   struct vnode *a_vp;
                   ufs_daddr_t  a_bn;
                   struct vnode **a_vpp;
                   ufs_daddr_t *a_bnp;
                   int *a_runp;
           } */ *ap;
   {
   
           if (ap->a_vpp != NULL)
                   *ap->a_vpp = ap->a_vp;
           if (ap->a_bnp != NULL)
                   *ap->a_bnp = ap->a_bn;
           if (ap->a_runp != NULL)
                   *ap->a_runp = 0;
           return (0);
   }
   
   /*
    * Memory filesystem close routine
    */
   /* ARGSUSED */
   static int
   mfs_close(ap)
           struct vop_close_args /* {
                   struct vnode *a_vp;
                   int  a_fflag;
                   struct ucred *a_cred;
                   struct proc *a_p;
           } */ *ap;
   {
           register struct vnode *vp = ap->a_vp;
           register struct mfsnode *mfsp = VTOMFS(vp);
           register struct buf *bp;
           int error;
   
           /*
            * Finish any pending I/O requests.
            */
           while ((bp = bufq_first(&mfsp->buf_queue)) != NULL) {
                   bufq_remove(&mfsp->buf_queue, bp);
                   mfs_doio(bp, mfsp);
                   wakeup((caddr_t)bp);
           }
           /*
            * On last close of a memory filesystem
            * we must invalidate any in core blocks, so that
            * we can, free up its vnode.
            */
           if ((error = vinvalbuf(vp, 1, ap->a_cred, ap->a_p, 0, 0)) != 0)
                   return (error);
           /*
            * There should be no way to have any more uses of this
            * vnode, so if we find any other uses, it is a panic.
            */
           if (vp->v_usecount > 1)
                   printf("mfs_close: ref count %d > 1\n", vp->v_usecount);
           if (vp->v_usecount > 1 || (bufq_first(&mfsp->buf_queue) != NULL))
                   panic("mfs_close");
           /*
            * Send a request to the filesystem server to exit.
            */
           mfsp->mfs_active = 0;
           wakeup((caddr_t)vp);
           return (0);
   }
   
   /*
    * Memory filesystem inactive routine
    */
   /* ARGSUSED */
   static int
   mfs_inactive(ap)
           struct vop_inactive_args /* {
                   struct vnode *a_vp;
                   struct proc *a_p;
           } */ *ap;
   {
           struct vnode *vp = ap->a_vp;
           struct mfsnode *mfsp = VTOMFS(vp);
   
           if (bufq_first(&mfsp->buf_queue) != NULL)
                   panic("mfs_inactive: not inactive (next buffer %p)",
                           bufq_first(&mfsp->buf_queue));
           VOP_UNLOCK(vp, 0, ap->a_p);
           return (0);
   }
   
   /*
    * Reclaim a memory filesystem devvp so that it can be reused.
    */
   static int
   mfs_reclaim(ap)
           struct vop_reclaim_args /* {
                   struct vnode *a_vp;
           } */ *ap;
   {
           register struct vnode *vp = ap->a_vp;
   
           FREE(vp->v_data, M_MFSNODE);
           vp->v_data = NULL;
           return (0);
   }
   
   /*
    * Print out the contents of an mfsnode.
    */
   static int
   mfs_print(ap)
           struct vop_print_args /* {
                   struct vnode *a_vp;
           } */ *ap;
   {
           register struct mfsnode *mfsp = VTOMFS(ap->a_vp);
   
           printf("tag VT_MFS, pid %ld, base %p, size %ld\n",
               (long)mfsp->mfs_pid, (void *)mfsp->mfs_baseoff, mfsp->mfs_size);
           return (0);
   }
   
   /*
    * Block device bad operation
    */
   static int
   mfs_badop(struct vop_generic_args *ap)
   {
           int i;
   
           printf("mfs_badop[%s]\n", ap->a_desc->vdesc_name);
           i = vop_defaultop(ap);
           printf("mfs_badop[%s] = %d\n", ap->a_desc->vdesc_name,i);
           return (i);
   }
   
   
   static int
   mfs_getpages(ap)
           struct vop_getpages_args *ap;
   {
   
           return (VOCALL(spec_vnodeop_p, VOFFSET(vop_getpages), ap));
   }

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