51df594922
as this can lead to deadlock. Submitted by: Mat dillon <dillon@freebsd.org>
469 lines
12 KiB
C
469 lines
12 KiB
C
/*
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* Copyright (c) 1989, 1990, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)mfs_vfsops.c 8.11 (Berkeley) 6/19/95
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* $Id: mfs_vfsops.c,v 1.56 1999/01/28 00:57:54 dillon Exp $
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*/
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#include "opt_mfs.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/buf.h>
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#include <sys/mount.h>
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#include <sys/signalvar.h>
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#include <sys/vnode.h>
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#include <sys/malloc.h>
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#include <sys/linker.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/ufsmount.h>
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#include <ufs/ufs/ufs_extern.h>
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#include <ufs/ffs/fs.h>
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#include <ufs/ffs/ffs_extern.h>
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#include <ufs/mfs/mfsnode.h>
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#include <ufs/mfs/mfs_extern.h>
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MALLOC_DEFINE(M_MFSNODE, "MFS node", "MFS vnode private part");
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u_char * mfs_getimage __P((void));
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#ifdef MFS_ROOT
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static caddr_t mfs_rootbase; /* address of mini-root in kernel virtual memory */
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static u_long mfs_rootsize; /* size of mini-root in bytes */
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#endif
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static int mfs_minor; /* used for building internal dev_t */
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extern vop_t **mfs_vnodeop_p;
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static int mfs_mount __P((struct mount *mp,
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char *path, caddr_t data, struct nameidata *ndp,
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struct proc *p));
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static int mfs_start __P((struct mount *mp, int flags, struct proc *p));
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static int mfs_statfs __P((struct mount *mp, struct statfs *sbp,
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struct proc *p));
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static int mfs_init __P((struct vfsconf *));
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/*
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* mfs vfs operations.
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*/
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static struct vfsops mfs_vfsops = {
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mfs_mount,
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mfs_start,
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ffs_unmount,
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ufs_root,
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ufs_quotactl,
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mfs_statfs,
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ffs_sync,
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ffs_vget,
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ffs_fhtovp,
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ffs_vptofh,
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mfs_init,
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};
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VFS_SET(mfs_vfsops, mfs, 0);
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#ifdef MFS_ROOT
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#ifdef MFS_ROOT_SIZE
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/* Image was already written into mfs_root */
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static u_char mfs_root[MFS_ROOT_SIZE*1024] = "MFS Filesystem goes here";
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static u_char end_mfs_root[] __unused = "MFS Filesystem had better STOP here";
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#endif
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u_char *
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mfs_getimage(void)
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{
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#ifdef MFS_ROOT_SIZE
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/* Get it from compiled-in code */
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return mfs_root;
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#else
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caddr_t p;
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vm_offset_t *q;
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p = preload_search_by_type("mfs_root");
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if (!p)
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return NULL;
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q = (vm_offset_t *)preload_search_info(p, MODINFO_ADDR);
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if (!q)
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return NULL;
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return (u_char *)*q;
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#endif
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}
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#endif /* MFS_ROOT */
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/*
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* mfs_mount
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*
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* Called when mounting local physical media
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*
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* PARAMETERS:
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* mountroot
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* mp mount point structure
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* path NULL (flag for root mount!!!)
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* data <unused>
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* ndp <unused>
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* p process (user credentials check [statfs])
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*
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* mount
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* mp mount point structure
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* path path to mount point
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* data pointer to argument struct in user space
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* ndp mount point namei() return (used for
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* credentials on reload), reused to look
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* up block device.
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* p process (user credentials check)
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*
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* RETURNS: 0 Success
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* !0 error number (errno.h)
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*
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* LOCK STATE:
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*
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* ENTRY
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* mount point is locked
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* EXIT
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* mount point is locked
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*
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* NOTES:
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* A NULL path can be used for a flag since the mount
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* system call will fail with EFAULT in copyinstr in
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* namei() if it is a genuine NULL from the user.
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*/
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/* ARGSUSED */
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static int
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mfs_mount(mp, path, data, ndp, p)
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register struct mount *mp;
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char *path;
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caddr_t data;
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struct nameidata *ndp;
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struct proc *p;
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{
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struct vnode *devvp;
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struct mfs_args args;
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struct ufsmount *ump;
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struct fs *fs;
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#ifdef MFS_ROOT
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u_char *base;
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#endif
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struct mfsnode *mfsp;
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u_int size;
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int flags, err;
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/*
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* Use NULL path to flag a root mount
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*/
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if( path == NULL) {
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/*
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***
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* Mounting root file system
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***
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*/
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#ifdef MFS_ROOT
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/* Get it from preload area */
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base = mfs_getimage();
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if (!base)
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panic("No mfs_root image loaded; can't continue!");
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fs = (struct fs *)(base + SBOFF);
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/* check for valid super block */
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if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
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fs->fs_bsize < sizeof(struct fs)) {
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panic("MFS image is invalid!!");
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}
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mfs_rootbase = base;
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mfs_rootsize = fs->fs_fsize * fs->fs_size;
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rootdev = makedev(255, mfs_minor++);
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printf("rootfs is %ld Kbyte compiled in MFS\n",
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mfs_rootsize/1024);
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if ((err = bdevvp(rootdev, &rootvp))) {
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printf("mfs_mountroot: can't find rootvp");
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return (err);
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}
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/*
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* FS specific handling
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*/
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MALLOC(mfsp, struct mfsnode *, sizeof *mfsp, M_MFSNODE, M_WAITOK);
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rootvp->v_data = mfsp;
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rootvp->v_op = mfs_vnodeop_p;
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rootvp->v_tag = VT_MFS;
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mfsp->mfs_baseoff = mfs_rootbase;
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mfsp->mfs_size = mfs_rootsize;
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mfsp->mfs_vnode = rootvp;
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mfsp->mfs_pid = p->p_pid;
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mfsp->mfs_active = 1;
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bufq_init(&mfsp->buf_queue);
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/* MFS wants to be read/write */
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mp->mnt_flag &= ~MNT_RDONLY;
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/*
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* Attempt mount
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*/
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if( (err = ffs_mountfs(rootvp, mp, p, M_MFSNODE)) != 0 ) {
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/* fs specific cleanup (if any)*/
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rootvp->v_data = NULL;
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FREE(mfsp, M_MFSNODE);
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goto error_1;
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}
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goto dostatfs; /* success*/
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#else /* !MFS_ROOT */
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/* you loose */
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panic("mfs_mount: mount MFS as root: not configured!");
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#endif /* MFS_ROOT */
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}
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/*
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***
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* Mounting non-root file system or updating a file system
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***
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*/
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/* copy in user arguments*/
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if ((err = copyin(data, (caddr_t)&args, sizeof (struct mfs_args))) != 0)
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goto error_1;
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/*
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* If updating, check whether changing from read-only to
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* read/write; if there is no device name, that's all we do.
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*/
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if (mp->mnt_flag & MNT_UPDATE) {
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/*
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********************
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* UPDATE
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********************
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*/
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ump = VFSTOUFS(mp);
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fs = ump->um_fs;
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if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
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flags = WRITECLOSE;
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if (mp->mnt_flag & MNT_FORCE)
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flags |= FORCECLOSE;
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err = ffs_flushfiles(mp, flags, p);
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if (err)
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goto error_1;
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}
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if (fs->fs_ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR))
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fs->fs_ronly = 0;
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#ifdef EXPORTMFS
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/* if not updating name...*/
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if (args.fspec == 0) {
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/*
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* Process export requests. Jumping to "success"
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* will return the vfs_export() error code.
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*/
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err = vfs_export(mp, &ump->um_export, &args.export);
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goto success;
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}
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#endif
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/* XXX MFS does not support name updating*/
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goto success;
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}
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/*
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* Do the MALLOC before the getnewvnode since doing so afterward
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* might cause a bogus v_data pointer to get dereferenced
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* elsewhere if MALLOC should block.
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*/
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MALLOC(mfsp, struct mfsnode *, sizeof *mfsp, M_MFSNODE, M_WAITOK);
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err = getnewvnode(VT_MFS, (struct mount *)0, mfs_vnodeop_p, &devvp);
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if (err) {
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FREE(mfsp, M_MFSNODE);
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goto error_1;
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}
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devvp->v_type = VBLK;
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if (checkalias(devvp, makedev(255, mfs_minor++), (struct mount *)0))
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panic("mfs_mount: dup dev");
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devvp->v_data = mfsp;
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mfsp->mfs_baseoff = args.base;
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mfsp->mfs_size = args.size;
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mfsp->mfs_vnode = devvp;
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mfsp->mfs_pid = p->p_pid;
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mfsp->mfs_active = 1;
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bufq_init(&mfsp->buf_queue);
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/*
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* Since this is a new mount, we want the names for
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* the device and the mount point copied in. If an
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* error occurs, the mountpoint is discarded by the
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* upper level code.
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*/
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/* Save "last mounted on" info for mount point (NULL pad)*/
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copyinstr( path, /* mount point*/
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mp->mnt_stat.f_mntonname, /* save area*/
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MNAMELEN - 1, /* max size*/
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&size); /* real size*/
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bzero( mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
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/* Save "mounted from" info for mount point (NULL pad)*/
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copyinstr( args.fspec, /* device name*/
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mp->mnt_stat.f_mntfromname, /* save area*/
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MNAMELEN - 1, /* max size*/
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&size); /* real size*/
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bzero( mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
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if ((err = ffs_mountfs(devvp, mp, p, M_MFSNODE)) != 0) {
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mfsp->mfs_active = 0;
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goto error_2;
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}
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#ifdef MFS_ROOT
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dostatfs:
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#endif
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/*
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* Initialize FS stat information in mount struct; uses both
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* mp->mnt_stat.f_mntonname and mp->mnt_stat.f_mntfromname
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*
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* This code is common to root and non-root mounts
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*/
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(void) VFS_STATFS(mp, &mp->mnt_stat, p);
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goto success;
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error_2: /* error with devvp held*/
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/* release devvp before failing*/
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vrele(devvp);
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error_1: /* no state to back out*/
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success:
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return( err);
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}
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static int mfs_pri = PWAIT | PCATCH; /* XXX prob. temp */
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/*
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* Used to grab the process and keep it in the kernel to service
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* memory filesystem I/O requests.
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*
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* Loop servicing I/O requests.
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* Copy the requested data into or out of the memory filesystem
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* address space.
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*/
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/* ARGSUSED */
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static int
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mfs_start(mp, flags, p)
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struct mount *mp;
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int flags;
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struct proc *p;
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{
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register struct vnode *vp = VFSTOUFS(mp)->um_devvp;
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register struct mfsnode *mfsp = VTOMFS(vp);
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register struct buf *bp;
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register int gotsig = 0;
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/*
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* We must set P_NOSWAP to prevent the system from trying to swap
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* out or kill ( when swap space is low, see vm/pageout.c ) the
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* process. A deadlock can occur if the process is swapped out,
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* and the system can loop trying to kill the unkillable ( while
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* references exist ) MFS process when swap space is low.
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*/
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curproc->p_flag |= P_NOSWAP;
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while (mfsp->mfs_active) {
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int s;
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s = splbio();
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while ((bp = bufq_first(&mfsp->buf_queue)) != NULL) {
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bufq_remove(&mfsp->buf_queue, bp);
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splx(s);
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mfs_doio(bp, mfsp);
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wakeup((caddr_t)bp);
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s = splbio();
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}
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splx(s);
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/*
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* If a non-ignored signal is received, try to unmount.
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* If that fails, clear the signal (it has been "processed"),
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* otherwise we will loop here, as tsleep will always return
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* EINTR/ERESTART.
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*/
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/*
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* Note that dounmount() may fail if work was queued after
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* we slept. We have to jump hoops here to make sure that we
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* process any buffers after the sleep, before we dounmount()
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*/
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if (gotsig) {
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gotsig = 0;
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if (dounmount(mp, 0, p) != 0)
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CLRSIG(p, CURSIG(p)); /* try sleep again.. */
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}
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else if (tsleep((caddr_t)vp, mfs_pri, "mfsidl", 0))
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gotsig++; /* try to unmount in next pass */
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}
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return (0);
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}
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/*
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* Get file system statistics.
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*/
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static int
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mfs_statfs(mp, sbp, p)
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struct mount *mp;
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struct statfs *sbp;
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struct proc *p;
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{
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int error;
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error = ffs_statfs(mp, sbp, p);
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sbp->f_type = mp->mnt_vfc->vfc_typenum;
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return (error);
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}
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/*
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* Memory based filesystem initialization.
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*/
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static int
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mfs_init(vfsp)
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struct vfsconf *vfsp;
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{
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return (0);
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}
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