freebsd-dev/sys/fs/fdescfs/fdesc_vfsops.c
Jeff Roberson e6e370a7fe - Replace v_flag with v_iflag and v_vflag
- v_vflag is protected by the vnode lock and is used when synchronization
   with VOP calls is needed.
 - v_iflag is protected by interlock and is used for dealing with vnode
   management issues.  These flags include X/O LOCK, FREE, DOOMED, etc.
 - All accesses to v_iflag and v_vflag have either been locked or marked with
   mp_fixme's.
 - Many ASSERT_VOP_LOCKED calls have been added where the locking was not
   clear.
 - Many functions in vfs_subr.c were restructured to provide for stronger
   locking.

Idea stolen from:	BSD/OS
2002-08-04 10:29:36 +00:00

228 lines
5.9 KiB
C

/*
* Copyright (c) 1992, 1993, 1995
* The Regents of the University of California. 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. 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.
*
* @(#)fdesc_vfsops.c 8.4 (Berkeley) 1/21/94
*
* $FreeBSD$
*/
/*
* /dev/fd Filesystem
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/vnode.h>
#include <fs/fdescfs/fdesc.h>
static MALLOC_DEFINE(M_FDESCMNT, "FDESC mount", "FDESC mount structure");
static int fdesc_mount(struct mount *mp, struct nameidata *ndp,
struct thread *td);
static int fdesc_unmount(struct mount *mp, int mntflags,
struct thread *td);
static int fdesc_statfs(struct mount *mp, struct statfs *sbp,
struct thread *td);
/*
* Mount the per-process file descriptors (/dev/fd)
*/
static int
fdesc_mount(mp, ndp, td)
struct mount *mp;
struct nameidata *ndp;
struct thread *td;
{
int error = 0;
struct fdescmount *fmp;
struct vnode *rvp;
/*
* Update is a no-op
*/
if (mp->mnt_flag & MNT_UPDATE)
return (EOPNOTSUPP);
error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp, td);
if (error)
return (error);
MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount),
M_FDESCMNT, M_WAITOK); /* XXX */
rvp->v_type = VDIR;
rvp->v_vflag |= VV_ROOT;
fmp->f_root = rvp;
/* XXX -- don't mark as local to work around fts() problems */
/*mp->mnt_flag |= MNT_LOCAL;*/
mp->mnt_data = (qaddr_t) fmp;
vfs_getnewfsid(mp);
bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc"));
(void)fdesc_statfs(mp, &mp->mnt_stat, td);
return (0);
}
static int
fdesc_unmount(mp, mntflags, td)
struct mount *mp;
int mntflags;
struct thread *td;
{
int error;
int flags = 0;
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
/*
* Clear out buffer cache. I don't think we
* ever get anything cached at this level at the
* moment, but who knows...
*
* There is 1 extra root vnode reference corresponding
* to f_root.
*/
if ((error = vflush(mp, 1, flags)) != 0)
return (error);
/*
* Finally, throw away the fdescmount structure
*/
free(mp->mnt_data, M_FDESCMNT); /* XXX */
mp->mnt_data = 0;
return (0);
}
int
fdesc_root(mp, vpp)
struct mount *mp;
struct vnode **vpp;
{
struct thread *td = curthread; /* XXX */
struct vnode *vp;
/*
* Return locked reference to root.
*/
vp = VFSTOFDESC(mp)->f_root;
VREF(vp);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
*vpp = vp;
return (0);
}
static int
fdesc_statfs(mp, sbp, td)
struct mount *mp;
struct statfs *sbp;
struct thread *td;
{
struct filedesc *fdp;
int lim;
int i;
int last;
int freefd;
/*
* Compute number of free file descriptors.
* [ Strange results will ensue if the open file
* limit is ever reduced below the current number
* of open files... ]
*/
lim = td->td_proc->p_rlimit[RLIMIT_NOFILE].rlim_cur;
fdp = td->td_proc->p_fd;
FILEDESC_LOCK(fdp);
last = min(fdp->fd_nfiles, lim);
freefd = 0;
for (i = fdp->fd_freefile; i < last; i++)
if (fdp->fd_ofiles[i] == NULL)
freefd++;
/*
* Adjust for the fact that the fdesc array may not
* have been fully allocated yet.
*/
if (fdp->fd_nfiles < lim)
freefd += (lim - fdp->fd_nfiles);
FILEDESC_UNLOCK(fdp);
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 = lim + 1; /* Allow for "." */
sbp->f_ffree = freefd; /* See comments above */
if (sbp != &mp->mnt_stat) {
sbp->f_type = mp->mnt_vfc->vfc_typenum;
bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
}
return (0);
}
static struct vfsops fdesc_vfsops = {
NULL,
vfs_stdstart,
fdesc_unmount,
fdesc_root,
vfs_stdquotactl,
fdesc_statfs,
vfs_stdsync,
vfs_stdvget,
vfs_stdfhtovp,
vfs_stdcheckexp,
vfs_stdvptofh,
fdesc_init,
vfs_stduninit,
vfs_stdextattrctl,
fdesc_mount,
};
VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC);