FreeBSD/Linux Kernel Cross Reference
sys/fs/devfs/devfs_vfsops.c

     /*-
      * Copyright (c) 1992, 1993, 1995
      *      The Regents of the University of California.  All rights reserved.
      * Copyright (c) 2000
      *      Poul-Henning Kamp.  All rights reserved.
      *
      * This code is derived from software donated to Berkeley by
      * Jan-Simon Pendry.
      *
     * 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. 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.
     *
     *      @(#)kernfs_vfsops.c     8.10 (Berkeley) 5/14/95
     * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
     *
     * $FreeBSD: releng/6.4/sys/fs/devfs/devfs_vfsops.c 163792 2006-10-30 15:33:38Z kib $
     */
    
    #include "opt_devfs.h"
    #include "opt_mac.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/mac.h>
    #include <sys/malloc.h>
    #include <sys/mount.h>
    #include <sys/proc.h>
    #include <sys/sx.h>
    #include <sys/vnode.h>
    #include <sys/limits.h>
    
    #include <fs/devfs/devfs.h>
    
    static struct unrhdr    *devfs_unr;
    
    MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
    
    static vfs_mount_t      devfs_mount;
    static vfs_unmount_t    devfs_unmount;
    static vfs_root_t       devfs_root;
    static vfs_statfs_t     devfs_statfs;
    
    /*
     * Mount the filesystem
     */
    static int
    devfs_mount(struct mount *mp, struct thread *td)
    {
            int error;
            struct devfs_mount *fmp;
            struct vnode *rvp;
    
            if (devfs_unr == NULL)
                    devfs_unr = new_unrhdr(0, INT_MAX, NULL);
    
            error = 0;
    
            if (mp->mnt_flag & (MNT_UPDATE | MNT_ROOTFS))
                    return (EOPNOTSUPP);
    
            fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
            fmp->dm_idx = alloc_unr(devfs_unr);
            sx_init(&fmp->dm_lock, "devfsmount");
            fmp->dm_holdcnt = 1;
    
            MNT_ILOCK(mp);
            mp->mnt_flag |= MNT_LOCAL;
            mp->mnt_kern_flag |= MNTK_MPSAFE;
    #ifdef MAC
            mp->mnt_flag |= MNT_MULTILABEL;
    #endif
            MNT_IUNLOCK(mp);
            fmp->dm_mount = mp;
            mp->mnt_data = (void *) fmp;
            vfs_getnewfsid(mp);
    
            fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
    
            error = devfs_root(mp, LK_EXCLUSIVE, &rvp, td);
           if (error) {
                   sx_destroy(&fmp->dm_lock);
                   free_unr(devfs_unr, fmp->dm_idx);
                   free(fmp, M_DEVFS);
                   return (error);
           }
   
           VOP_UNLOCK(rvp, 0, td);
   
           vfs_mountedfrom(mp, "devfs");
   
           return (0);
   }
   
   void
   devfs_unmount_final(struct devfs_mount *fmp)
   {
           sx_destroy(&fmp->dm_lock);
           free(fmp, M_DEVFS);
   }
   
   static int
   devfs_unmount(struct mount *mp, int mntflags, struct thread *td)
   {
           int error;
           int flags = 0;
           struct devfs_mount *fmp;
           int hold;
           u_int idx;
   
           fmp = VFSTODEVFS(mp);
           KASSERT(fmp->dm_mount != NULL,
                   ("devfs_unmount unmounted devfs_mount"));
           /* There is 1 extra root vnode reference from devfs_mount(). */
           error = vflush(mp, 1, flags, td);
           if (error)
                   return (error);
           sx_xlock(&fmp->dm_lock);
           devfs_cleanup(fmp);
           devfs_rules_cleanup(fmp);
           fmp->dm_mount = NULL;
           hold = --fmp->dm_holdcnt;
           mp->mnt_data = NULL;
           idx = fmp->dm_idx;
           sx_xunlock(&fmp->dm_lock);
           free_unr(devfs_unr, idx);
           if (hold == 0)
                   devfs_unmount_final(fmp);
           return 0;
   }
   
   /* Return locked reference to root.  */
   
   static int
   devfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
   {
           int error;
           struct vnode *vp;
           struct devfs_mount *dmp;
   
           dmp = VFSTODEVFS(mp);
           sx_xlock(&dmp->dm_lock);
           error = devfs_allocv(dmp->dm_rootdir, mp, &vp, td);
           if (error)
                   return (error);
           vp->v_vflag |= VV_ROOT;
           *vpp = vp;
           return (0);
   }
   
   static int
   devfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
   {
   
           sbp->f_flags = 0;
           sbp->f_bsize = DEV_BSIZE;
           sbp->f_iosize = DEV_BSIZE;
           sbp->f_blocks = 2;              /* 1K to keep df happy */
           sbp->f_bfree = 0;
           sbp->f_bavail = 0;
           sbp->f_files = 0;
           sbp->f_ffree = 0;
           return (0);
   }
   
   static struct vfsops devfs_vfsops = {
           .vfs_mount =            devfs_mount,
           .vfs_root =             devfs_root,
           .vfs_statfs =           devfs_statfs,
           .vfs_unmount =          devfs_unmount,
   };
   
   VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC);

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