95e5e988e0
original BSD code. The association between the vnode and the vm_object no longer includes reference counts. The major difference is that vm_object's are no longer freed gratuitiously from the vnode, and so once an object is created for the vnode, it will last as long as the vnode does. When a vnode object reference count is incremented, then the underlying vnode reference count is incremented also. The two "objects" are now more intimately related, and so the interactions are now much less complex. When vnodes are now normally placed onto the free queue with an object still attached. The rundown of the object happens at vnode rundown time, and happens with exactly the same filesystem semantics of the original VFS code. There is absolutely no need for vnode_pager_uncache and other travesties like that anymore. A side-effect of these changes is that SMP locking should be much simpler, the I/O copyin/copyout optimizations work, NFS should be more ponderable, and further work on layered filesystems should be less frustrating, because of the totally coherent management of the vnode objects and vnodes. Please be careful with your system while running this code, but I would greatly appreciate feedback as soon a reasonably possible.
95 lines
3.0 KiB
C
95 lines
3.0 KiB
C
/*
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* Copyright (c) 1982, 1986, 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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* @(#)uio.h 8.5 (Berkeley) 2/22/94
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* $Id: uio.h,v 1.8 1997/12/19 10:03:31 bde Exp $
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*/
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#ifndef _SYS_UIO_H_
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#define _SYS_UIO_H_
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/*
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* XXX
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* iov_base should be a void *.
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*/
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struct iovec {
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char *iov_base; /* Base address. */
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size_t iov_len; /* Length. */
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};
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enum uio_rw { UIO_READ, UIO_WRITE };
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/* Segment flag values. */
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enum uio_seg {
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UIO_USERSPACE, /* from user data space */
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UIO_SYSSPACE, /* from system space */
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UIO_USERISPACE, /* from user I space */
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UIO_NOCOPY /* don't copy, already in object */
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};
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#ifdef KERNEL
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struct uio {
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struct iovec *uio_iov;
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int uio_iovcnt;
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off_t uio_offset;
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int uio_resid;
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enum uio_seg uio_segflg;
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enum uio_rw uio_rw;
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struct proc *uio_procp;
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};
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/*
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* Limits
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*/
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#define UIO_MAXIOV 1024 /* max 1K of iov's */
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#define UIO_SMALLIOV 8 /* 8 on stack, else malloc */
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struct vm_object;
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int uiomove __P((caddr_t, int, struct uio *));
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int uiomoveco __P((caddr_t, int, struct uio *, struct vm_object *));
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int uioread __P((int, struct uio *, struct vm_object *, int *));
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#else /* !KERNEL */
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#include <sys/cdefs.h>
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__BEGIN_DECLS
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ssize_t readv __P((int, const struct iovec *, int));
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ssize_t writev __P((int, const struct iovec *, int));
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__END_DECLS
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#endif /* KERNEL */
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#endif /* !_SYS_UIO_H_ */
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