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Diffstat (limited to 'share/doc/papers/memfs/A.t')
| -rw-r--r-- | share/doc/papers/memfs/A.t | 173 |
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diff --git a/share/doc/papers/memfs/A.t b/share/doc/papers/memfs/A.t deleted file mode 100644 index 09d8e93..0000000 --- a/share/doc/papers/memfs/A.t +++ /dev/null @@ -1,173 +0,0 @@ -.\" Copyright (c) 1990 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. -.\" -.\" @(#)A.t 5.1 (Berkeley) 4/16/91 -.\" -.bp -.nr PS 10 -.nr VS 12 -.NH -Appendix A - Implementation Details -.LP -.nf -.vS -/* - * This structure defines the control data for the memory - * based file system. - */ -struct mfsnode { - struct vnode *mfs_vnode; /* vnode associated with this mfsnode */ - caddr_t mfs_baseoff; /* base of file system in memory */ - long mfs_size; /* size of memory file system */ - pid_t mfs_pid; /* supporting process pid */ - struct buf *mfs_buflist; /* list of I/O requests */ -}; - -/* - * Convert between mfsnode pointers and vnode pointers - */ -#define VTOMFS(vp) ((struct mfsnode *)(vp)->v_data) -#define MFSTOV(mfsp) ((mfsp)->mfs_vnode) -#define MFS_EXIT (struct buf *)-1 - -/* - * Arguments to mount MFS - */ -struct mfs_args { - char *name; /* name to export for statfs */ - caddr_t base; /* base address of file system in memory */ - u_long size; /* size of file system */ -}; -.bp -/* - * Mount an MFS filesystem. - */ -mfs_mount(mp, path, data) - struct mount *mp; - char *path; - caddr_t data; -{ - struct vnode *devvp; - struct mfsnode *mfsp; - struct buf *bp; - struct mfs_args args; - - /* - * Create a block device to represent the disk. - */ - devvp = getnewvnode(VT_MFS, VBLK, &mfs_vnodeops); - mfsp = VTOMFS(devvp); - /* - * Save base address of the filesystem from the supporting process. - */ - copyin(data, &args, (sizeof mfs_args)); - mfsp->mfs_baseoff = args.base; - mfsp->mfs_size = args.size; - /* - * Record the process identifier of the supporting process. - */ - mfsp->mfs_pid = u.u_procp->p_pid; - /* - * Mount the filesystem. - */ - mfsp->mfs_buflist = NULL; - mountfs(devvp, mp); - /* - * Loop processing I/O requests. - */ - while (mfsp->mfs_buflist != MFS_EXIT) { - while (mfsp->mfs_buflist != NULL) { - bp = mfsp->mfs_buflist; - mfsp->mfs_buflist = bp->av_forw; - offset = mfsp->mfs_baseoff + (bp->b_blkno * DEV_BSIZE); - if (bp->b_flags & B_READ) - copyin(offset, bp->b_un.b_addr, bp->b_bcount); - else /* write_request */ - copyout(bp->b_un.b_addr, offset, bp->b_bcount); - biodone(bp); - } - sleep((caddr_t)devvp, PWAIT); - } -} -.bp -/* - * If the MFS process requests the I/O then we must do it directly. - * Otherwise put the request on the list and request the MFS process - * to be run. - */ -mfs_strategy(bp) - struct buf *bp; -{ - struct vnode *devvp; - struct mfsnode *mfsp; - off_t offset; - - devvp = bp->b_vp; - mfsp = VTOMFS(devvp); - if (mfsp->mfs_pid == u.u_procp->p_pid) { - offset = mfsp->mfs_baseoff + (bp->b_blkno * DEV_BSIZE); - if (bp->b_flags & B_READ) - copyin(offset, bp->b_un.b_addr, bp->b_bcount); - else /* write_request */ - copyout(bp->b_un.b_addr, offset, bp->b_bcount); - biodone(bp); - } else { - bp->av_forw = mfsp->mfs_buflist; - mfsp->mfs_buflist = bp; - wakeup((caddr_t)bp->b_vp); - } -} - -/* - * The close routine is called by unmount after the filesystem - * has been successfully unmounted. - */ -mfs_close(devvp) - struct vnode *devvp; -{ - struct mfsnode *mfsp = VTOMFS(vp); - struct buf *bp; - - /* - * Finish any pending I/O requests. - */ - while (bp = mfsp->mfs_buflist) { - mfsp->mfs_buflist = bp->av_forw; - mfs_doio(bp, mfsp->mfs_baseoff); - wakeup((caddr_t)bp); - } - /* - * Send a request to the filesystem server to exit. - */ - mfsp->mfs_buflist = MFS_EXIT; - wakeup((caddr_t)vp); -} -.vE |
