1478 lines
42 KiB
Groff
1478 lines
42 KiB
Groff
.\" $NetBSD: vnodeops.9,v 1.60 2006/12/23 09:36:56 wiz Exp $
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.\"
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.\" Copyright (c) 2001, 2005, 2006 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Gregory McGarry.
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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 NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd December 9, 2006
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.Dt VNODEOPS 9
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.Os
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.Sh NAME
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.Nm vnodeops ,
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.Nm VOP_LOOKUP ,
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.Nm VOP_CREATE ,
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.Nm VOP_MKNOD ,
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.Nm VOP_OPEN ,
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.Nm VOP_CLOSE ,
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.Nm VOP_ACCESS ,
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.Nm VOP_GETATTR ,
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.Nm VOP_SETATTR ,
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.Nm VOP_READ ,
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.Nm VOP_WRITE ,
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.Nm VOP_IOCTL ,
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.Nm VOP_FCNTL ,
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.Nm VOP_POLL ,
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.Nm VOP_KQFILTER ,
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.Nm VOP_REVOKE ,
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.Nm VOP_MMAP ,
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.Nm VOP_FSYNC ,
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.Nm VOP_SEEK ,
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.Nm VOP_REMOVE ,
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.Nm VOP_LINK ,
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.Nm VOP_RENAME ,
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.Nm VOP_MKDIR ,
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.Nm VOP_RMDIR ,
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.Nm VOP_SYMLINK ,
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.Nm VOP_READDIR ,
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.Nm VOP_READLINK ,
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.Nm VOP_ABORTOP ,
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.Nm VOP_INACTIVE ,
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.Nm VOP_RECLAIM ,
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.Nm VOP_LOCK ,
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.Nm VOP_UNLOCK ,
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.Nm VOP_ISLOCKED ,
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.Nm VOP_BMAP ,
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.Nm VOP_PRINT ,
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.Nm VOP_PATHCONF ,
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.Nm VOP_ADVLOCK ,
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.Nm VOP_LEASE ,
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.Nm VOP_WHITEOUT ,
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.Nm VOP_GETPAGES ,
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.Nm VOP_PUTPAGES ,
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.Nm VOP_STRATEGY ,
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.Nm VOP_BWRITE ,
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.Nm VOP_GETEXTATTR ,
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.Nm VOP_SETEXTATTR ,
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.Nm VOP_LISTEXTATTR ,
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.Nd vnode operations
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/buf.h
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.In sys/dirent.h
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.In sys/lock.h
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.In sys/vnode.h
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.In sys/mount.h
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.In sys/namei.h
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.In sys/unistd.h
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.In sys/fcntl.h
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.In sys/lockf.h
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.In sys/extattr.h
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.Ft int
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.Fn VOP_LOOKUP "struct vnode *dvp" "struct vnode **vpp" \
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"struct componentname *cnp"
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.Ft int
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.Fn VOP_CREATE "struct vnode *dvp" "struct vnode **vpp" \
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"struct componentname *cnp" "struct vattr *vap"
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.Ft int
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.Fn VOP_MKNOD "struct vnode *dvp" "struct vnode **vpp" \
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"struct componentname *cnp" "struct vattr *vap"
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.Ft int
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.Fn VOP_OPEN "struct vnode *vp" "int mode" "kauth_cred_t cred" \
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"struct lwp *l"
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.Ft int
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.Fn VOP_CLOSE "struct vnode *vp" "int fflag" "kauth_cred_t cred" \
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"struct lwp *l"
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.Ft int
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.Fn VOP_ACCESS "struct vnode *vp" "int mode" "kauth_cred_t cred" \
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"struct lwp *l"
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.Ft int
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.Fn VOP_GETATTR "struct vnode *vp" "struct vattr *vap" \
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"kauth_cred_t cred" "struct lwp *l"
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.Ft int
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.Fn VOP_SETATTR "struct vnode *vp" "struct vattr *vap" \
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"kauth_cred_t cred" "struct lwp *l"
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.Ft int
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.Fn VOP_READ "struct vnode *vp" "struct uio *uio" "int ioflag" \
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"kauth_cred_t cred"
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.Ft int
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.Fn VOP_WRITE "struct vnode *vp" "struct uio *uio" "int ioflag" \
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"kauth_cred_t cred"
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.Ft int
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.Fn VOP_IOCTL "struct vnode *vp" "u_long command" "void *data" \
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"int fflag" "kauth_cred_t cred" "struct lwp *l"
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.Ft int
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.Fn VOP_FCNTL "struct vnode *vp" "u_int command" "void *data" \
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"int fflag" "kauth_cred_t cred" "struct lwp *l"
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.Ft int
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.Fn VOP_POLL "struct vnode *vp" "int events" "struct lwp *l"
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.Ft int
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.Fn VOP_KQFILTER "struct vnode *vp" "struct knote *kn"
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.Ft int
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.Fn VOP_REVOKE "struct vnode *vp" "int flags"
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.Ft int
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.Fn VOP_MMAP "struct vnode *vp" "int fflags" \
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"kauth_cred_t cred" "struct lwp *l"
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.Ft int
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.Fn VOP_FSYNC "struct vnode *vp" "kauth_cred_t cred" "int flags" \
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"off_t offlo" "off_t offhi" "struct lwp *l"
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.Ft int
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.Fn VOP_SEEK "struct vnode *vp" "off_t oldoff" "off_t newoff" \
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"kauth_cred_t cred"
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.Ft int
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.Fn VOP_REMOVE "struct vnode *vp" "struct vnode *vp" \
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"struct componentname *cnp"
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.Ft int
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.Fn VOP_LINK "struct vnode *dvp" "struct vnode *vp" \
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"struct componentname *cnp"
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.Ft int
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.Fn VOP_RENAME "struct vnode *fdvp" "struct vnode *fvp" \
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"struct componentname *fcnp" "struct vnode *tdvp" \
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"struct vnode *tvp" "struct componentname *tcnp"
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.Ft int
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.Fn VOP_MKDIR "struct vnode *dvp" "struct vnode **vpp" \
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"struct componentname *cnp" "struct vattr *vap"
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.Ft int
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.Fn VOP_RMDIR "struct vnode *dvp" "struct vnode *vp" \
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"struct componentname *cnp"
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.Ft int
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.Fn VOP_SYMLINK "struct vnode *dvp" "struct vnode **vpp" \
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"struct componentname *cnp" "struct vattr *vap" "char *target"
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.Ft int
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.Fn VOP_READDIR "struct vnode *vp" "struct uio *uio" \
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"kauth_cred_t cred" "int *eofflag" "off_t **cookies" "int *ncookies"
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.Ft int
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.Fn VOP_READLINK "struct vnode *vp" "struct uio *uio" "kauth_cred_t cred"
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.Ft int
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.Fn VOP_ABORTOP "struct vnode *dvp" "struct componentname *cnp"
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.Ft int
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.Fn VOP_INACTIVE "struct vnode *vp" "struct lwp *l"
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.Ft int
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.Fn VOP_RECLAIM "struct vnode *vp" "struct lwp *l"
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.Ft int
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.Fn VOP_LOCK "struct vnode *vp" "int flags"
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.Ft int
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.Fn VOP_UNLOCK "struct vnode *vp" "int flags"
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.Ft int
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.Fn VOP_ISLOCKED "struct vnode *vp"
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.Ft int
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.Fn VOP_BMAP "struct vnode *vp" "daddr_t bn" "struct vnode **vpp" \
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"daddr_t *bnp" "int *runp"
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.Ft int
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.Fn VOP_PRINT "struct vnode *vp"
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.Ft int
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.Fn VOP_PATHCONF "struct vnode *vp" "int name" "register_t *retval"
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.Ft int
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.Fn VOP_ADVLOCK "struct vnode *vp" "void *id" "int op" \
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"struct flock *fl" "int flags"
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.Ft int
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.Fn VOP_LEASE "struct vnode *vp" "struct lwp *l" "kauth_cred_t cred" \
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"int flag"
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.Ft int
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.Fn VOP_WHITEOUT "struct vnode *dvp" "struct componentname *cnp" \
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"int flags"
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.Ft int
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.Fn VOP_GETPAGES "struct vnode *vp" "voff_t offset" "struct vm_page **m" \
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"int *count" "int centeridx" "vm_prot_t access_type" "int advice" "int flags"
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.Ft int
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.Fn VOP_PUTPAGES "struct vnode *vp" "voff_t offlo" "voff_t offhi" \
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"int flags"
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.Ft int
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.Fn VOP_STRATEGY "struct vnode *vp" "struct buf *bp"
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.Ft int
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.Fn VOP_BWRITE "struct buf *bp"
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.Ft int
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.Fn VOP_GETEXTATTR "struct vnode *vp" "int attrnamespace" "const char *name" \
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"struct uio *uio" "size_t *size" "kauth_cred_t cred" "struct lwp *l"
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.Ft int
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.Fn VOP_SETEXTATTR "struct vnode *vp" "int attrnamespace" "const char *name" \
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"struct uio *uio" "kauth_cred_t cred" "struct lwp *l"
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.Ft int
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.Fn VOP_LISTEXTATTR "struct vnode *vp" "int attrnamespace" "struct uio *uio" \
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"size_t *size" "kauth_cred_t cred" "struct lwp *l"
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.Pp
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Not all header files are required for each function.
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.Sh DESCRIPTION
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The vnode operations vector describes what operations can be done to
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the file associated with the vnode.
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The system maintains one vnode operations vector for each file system
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type configured into the kernel.
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The vnode operations vector contains a pointer to a function for each
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operation supported by the file system.
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Many of the functions described in the vnode operations vector are
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closely related to their corresponding system calls.
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In most cases, they are called as a result of the system call
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associated with the operation being invoked.
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.Pp
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Functions in the vnode operations vector are invoked using specialised
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macros.
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The following table lists the elements of the vnode operations vector,
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the corresponding invocation macro, and a description of the element.
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.Pp
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.nf
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.ta \w'int (*vop_listextattr)()'u+2n +\w'VOP_LISTEXTATTR'u+2n +\w'Map file into user address space'u
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\fIVector element\fP \fIMacro\fP \fIDescription\fP
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.ta \w'int (*vop_listextattr)()'u+2n +\w'VOP_LISTEXTATTR'u+2n +\w'Map file into user address space'u+6nC
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.sp 5p
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int (*vop_lookup)() VOP_LOOKUP Lookup file name in name cache
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int (*vop_create)() VOP_CREATE Create a new file
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int (*vop_mknod)() VOP_MKNOD Make a new device
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int (*vop_open)() VOP_OPEN Open a file
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int (*vop_close)() VOP_CLOSE Close a file
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int (*vop_access)() VOP_ACCESS Determine file accessibility
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int (*vop_getattr)() VOP_GETATTR Get file attributes
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int (*vop_setattr)() VOP_SETATTR Set file attributes
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int (*vop_read)() VOP_READ Read from a file
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int (*vop_write)() VOP_WRITE Write to a file
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int (*vop_ioctl)() VOP_IOCTL Perform device-specific I/O
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int (*vop_fcntl)() VOP_FCNTL Perform file control
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int (*vop_poll)() VOP_POLL Test if poll event has occurred
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int (*vop_kqfilter)() VOP_KQFILTER Register a knote
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int (*vop_revoke)() VOP_REVOKE Eliminate vode activity
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int (*vop_mmap)() VOP_MMAP Map file into user address space
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int (*vop_fsync)() VOP_FSYNC Flush pending data to disk
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int (*vop_seek)() VOP_SEEK Test if file is seekable
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int (*vop_remove)() VOP_REMOVE Remove a file
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int (*vop_link)() VOP_LINK Link a file
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int (*vop_rename)() VOP_RENAME Rename a file
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int (*vop_mkdir)() VOP_MKDIR Make a new directory
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int (*vop_rmdir)() VOP_RMDIR Remove a directory
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int (*vop_symlink)() VOP_SYMLINK Create a symbolic link
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int (*vop_readdir)() VOP_READDIR Read directory entry
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int (*vop_readlink)() VOP_READLINK Read contents of a symlink
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int (*vop_abortop)() VOP_ABORTOP Abort pending operation
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int (*vop_inactive)() VOP_INACTIVE Release the inactive vnode
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int (*vop_reclaim)() VOP_RECLAIM Reclaim vnode for another file
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int (*vop_lock)() VOP_LOCK Sleep until vnode lock is free
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int (*vop_unlock)() VOP_UNLOCK Wake up process sleeping on lock
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int (*vop_islocked)() VOP_ISLOCKED Test if vnode is locked
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int (*vop_bmap)() VOP_BMAP Logical block number conversion
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int (*vop_print)() VOP_PRINT Print debugging information
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int (*vop_pathconf)() VOP_PATHCONF Return POSIX pathconf data
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int (*vop_advlock)() VOP_ADVLOCK Advisory record locking
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int (*vop_lease)() VOP_LEASE Validate vnode credentials
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int (*vop_whiteout)() VOP_WHITEOUT Whiteout vnode
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int (*vop_getpages)() VOP_GETPAGES Read VM pages from file
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int (*vop_putpages)() VOP_PUTPAGES Write VM pages to file
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int (*vop_strategy)() VOP_STRATEGY Read/write a file system buffer
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int (*vop_bwrite)() VOP_BWRITE Write a file system buffer
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int (*vop_getextattr)() VOP_GETEXTATTR Get extended attribute
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int (*vop_setextattr)() VOP_SETEXTATTR Set extended attribute
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int (*vop_listextattr)() VOP_LISTEXTATTR List extended attributes
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.fi
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.Pp
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The implementation details of the vnode operations vector are not
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quite what is described here.
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.Pp
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If the file system type does not support a specific operation, it must
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nevertheless assign an appropriate function in the vnode operations
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vector to do the minimum required of it.
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In most cases, such functions either do nothing or return an error
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value to the effect that it is not supported.
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.Pp
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Many of the functions in the vnode operations vector take a
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componentname structure.
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It is used to encapsulate many parameters into a single function
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argument.
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It has the following structure:
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.Bd -literal
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struct componentname {
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/*
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* Arguments to lookup.
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*/
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u_long cn_nameiop; /* namei operation */
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u_long cn_flags; /* flags to namei */
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struct lwp *cn_lwp; /* lwp requesting lookup */
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kauth_cred_t cn_cred; /* credentials */
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/*
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* Shared between lookup and commit routines.
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*/
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char *cn_pnbuf; /* pathname buffer */
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const char *cn_nameptr; /* pointer to looked up name */
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long cn_namelen; /* length of looked up component */
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u_long cn_hash; /* hash value of looked up name */
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long cn_consume; /* chars to consume in lookup() */
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};
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.Ed
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.Pp
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The top half of the structure is used exclusively for the pathname
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lookups using
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.Fn VOP_LOOKUP
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and is initialised by the caller.
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The semantics of the lookup are affected by the lookup operation
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specified in
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.Em cn_nameiop
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and the flags specified in
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.Em cn_flags .
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Valid operations are:
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.Pp
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.Bl -tag -offset indent -width LOOKUP -compact
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.It LOOKUP
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perform name lookup only
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.It CREATE
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set up for file creation
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.It DELETE
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set up for file deletion
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.It RENAME
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set up for file renaming
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.It OPMASK
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mask for operation
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.El
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.Pp
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Valid values for
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.Em cn-\*[Gt]cn_flags
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are:
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.Pp
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.Bl -tag -offset indent -width LOCKPARENT -compact
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.It LOCKLEAF
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lock inode on return
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.It LOCKPARENT
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want parent vnode returned locked
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.It NOCACHE
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name must not be left in name cache (see
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.Xr namecache 9 )
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.It FOLLOW
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follow symbolic links
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.It NOFOLLOW
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do not follow symbolic links (pseudo)
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.It MODMASK
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mask of operational modifiers
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.El
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.Pp
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No vnode operations may be called from interrupt context.
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Most operations also require the vnode to be locked on entry.
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To prevent deadlocks, when acquiring locks on multiple vnodes, the
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lock of parent directory must be acquired before the lock on the child
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directory.
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.Pp
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Vnode operations for a file system type generally should not be
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called directly from the kernel, but accessed indirectly through the
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high-level convenience functions discussed in
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.Xr vnsubr 9 .
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.Sh FUNCTIONS
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.Bl -tag -width compact
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.It Fn VOP_LOOKUP "dvp" "vpp" "cnp"
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Lookup a single pathname component in a given directory.
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The argument
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.Fa dvp
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is the locked vnode of the directory to search and
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.Fa cnp
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is the pathname component to be searched for.
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If the pathname component is found, the address of the resulting
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locked vnode is returned in
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.Fa vpp .
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The operation specified in
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.Em cnp-\*[Gt]cn_nameiop
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gives
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.Fn VOP_LOOKUP
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hints about the reason for requesting the lookup and uses it to cache
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file system type specific information in the vnode for subsequent
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operations.
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.Pp
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There are three types of lookups: ".", ".." (ISDOTDOT), and other.
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If the pathname component being searched for is ".", then
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.Fa dvp
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has an extra reference added to it and it is returned in
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.Fa *vpp .
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If the pathname component being search for is ".." (ISDOTDOT),
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.Fa dvp
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is unlocked, the ".." node is locked and then
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.Fa dvp
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is relocked.
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This process preserves the protocol of always locking nodes from root
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downward and prevents deadlock.
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For other pathname components,
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.Fn VOP_LOOKUP
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checks the accessibility of the directory and searches the name cache
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for the pathname component.
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See
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.Xr namecache 9 .
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If the pathname is not found in the name cache, the directory is
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searched for the pathname.
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The resulting locked vnode is returned in
|
|
.Fa vpp .
|
|
.Fa dvp
|
|
is always returned locked.
|
|
.Pp
|
|
On failure
|
|
.Fa *vpp
|
|
is
|
|
.Dv NULL ,
|
|
and
|
|
.Fa *dvp
|
|
is left locked.
|
|
If the operation is successful
|
|
.Fa *vpp
|
|
is locked and zero is returned.
|
|
Typically, if
|
|
.Fa *vpp
|
|
and
|
|
.Fa dvp
|
|
are the same vnode the caller will need to release twice (decrement
|
|
the reference count) and unlock once.
|
|
.It Fn VOP_CREATE "dvp" "vpp" "cnp" "vap"
|
|
Create a new file in a given directory.
|
|
The argument
|
|
.Fa dvp
|
|
is the locked vnode of the directory to create the new file in and
|
|
.Fa cnp
|
|
is the pathname component of the new file.
|
|
The argument
|
|
.Fa vap
|
|
specifies the attributes that the new file should be created with.
|
|
If the file is successfully created, the address of the resulting
|
|
locked vnode is returned in
|
|
.Fa vpp
|
|
and zero is returned.
|
|
Regardless of the return value, the directory vnode
|
|
.Fa dvp
|
|
will be unlocked on return.
|
|
.Pp
|
|
This function is called after
|
|
.Fn VOP_LOOKUP
|
|
when a file is being created.
|
|
Normally,
|
|
.Fn VOP_LOOKUP
|
|
will have set the SAVENAME flag in
|
|
.Em cnp-\*[Gt]cn_flags
|
|
to keep the memory pointed to by
|
|
.Em cnp-\*[Gt]cn_pnbuf
|
|
valid.
|
|
If an error is detected when creating the file, this memory is
|
|
released.
|
|
If the file is created successfully it will be released unless the
|
|
SAVESTART flags in specified in
|
|
.Em cnp-\*[Gt]cn_flags .
|
|
.It Fn VOP_MKNOD "dvp" "vpp" "cnp" "vap"
|
|
Make a new device-special file in a given directory.
|
|
The argument
|
|
.Fa dvp
|
|
is the locked vnode of the directory to create the new device-special
|
|
file in and
|
|
.Fa cnp
|
|
is the pathname component of the new device-special file.
|
|
The argument
|
|
.Fa vap
|
|
specifies the attributes that the new device-special file should be
|
|
created with.
|
|
If the file is successfully created, the address of the resulting
|
|
locked vnode is returned in
|
|
.Fa vpp
|
|
and zero is returned.
|
|
.Pp
|
|
This function is called after
|
|
.Fn VOP_LOOKUP
|
|
when a device-special file is being created.
|
|
Normally,
|
|
.Fn VOP_LOOKUP
|
|
will have set the SAVENAME flag in
|
|
.Em cnp-\*[Gt]cn_flags
|
|
to keep the memory pointed to by
|
|
.Em cnp-\*[Gt]cn_pnbuf
|
|
valid.
|
|
If an error is detected when creating the device-special file,
|
|
this memory is released.
|
|
If the device-special file is created successfully it will be released
|
|
unless the SAVESTART flags in specified in
|
|
.Em cnp-\*[Gt]cn_flags .
|
|
.It Fn VOP_OPEN "vp" "mode" "cred" "l"
|
|
Open a file.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to open and
|
|
.Fa mode
|
|
specifies the access mode required by the calling process.
|
|
The calling process and its credentials are specified by
|
|
.Fa l
|
|
and
|
|
.Fa cred
|
|
respectively.
|
|
The access mode is a set of flags, including FREAD, FWRITE,
|
|
O_NONBLOCK, O_APPEND, etc.
|
|
.Fn VOP_OPEN
|
|
must be called before a file can be accessed by a thread.
|
|
The vnode reference count is incremented.
|
|
.Pp
|
|
.Fn VOP_OPEN
|
|
expects the vnode
|
|
.Fa vp
|
|
to be locked on entry and will leave it locked on return.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.It Fn VOP_CLOSE "vp" "fflag" "cred" "l"
|
|
Close a file.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to close and
|
|
.Fa fflags
|
|
specifies the access mode by the calling process.
|
|
The calling process and its credentials are specified by
|
|
.Fa l
|
|
and
|
|
.Fa cred
|
|
respectively.
|
|
.Fn VOP_CLOSE
|
|
must be called after a file is finished with.
|
|
.Pp
|
|
.Fn VOP_CLOSE
|
|
expects at least a reference to be associated with the vnode and does
|
|
not care whether the vnode is locked.
|
|
The lock and reference state is left unchanged on return.
|
|
.It Fn VOP_ACCESS "vp" "mode" "cred" "l"
|
|
Determine the accessibility (permissions) of the file against the
|
|
specified credentials.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to check,
|
|
.Fa mode
|
|
is the type of access required,
|
|
.Fa cred
|
|
contains the user credentials to check and
|
|
.Fa l
|
|
is the process which is checking the credentials.
|
|
The argument
|
|
.Fa mode
|
|
is a mask which can contain VREAD, VWRITE or VEXEC.
|
|
If the file is accessible in the specified way, zero is returned,
|
|
otherwise an appropriate error code is returned.
|
|
.Pp
|
|
The vnode
|
|
.Fa vp
|
|
will be locked on entry and should remain locked on return.
|
|
.It Fn VOP_GETATTR "vp" "vap" "cred" "l"
|
|
Get specific vnode attributes on a file.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to get the attributes for.
|
|
The arguments
|
|
.Fa l
|
|
and
|
|
.Fa cred
|
|
specifies the calling process and its credentials respectively.
|
|
.Fn VOP_GETATTR
|
|
uses the file system type specific data object
|
|
.Em vp-\*[Gt]v_data
|
|
to reference the underlying file attributes.
|
|
Attributes associated with the file are collected by setting the
|
|
required attribute bits in
|
|
.Em vap-\*[Gt]va_mask .
|
|
The attributes are returned in
|
|
.Fa vap .
|
|
Attributes which are not available are set to the value VNOVAL.
|
|
.Pp
|
|
For more information on vnode attributes see
|
|
.Xr vattr 9 .
|
|
.It Fn VOP_SETATTR "vp" "vap" "cred" "l"
|
|
Set specific vnode attributes on a file.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file to set the attributes for.
|
|
The arguments
|
|
.Fa l
|
|
and
|
|
.Fa cred
|
|
specifies the calling process and its credentials respectively.
|
|
.Fn VOP_SETATTR
|
|
uses the file system type specific data object
|
|
.Em vp-\*[Gt]v_data
|
|
to reference the underlying file attributes.
|
|
The new attributes are defined in
|
|
.Fa vap .
|
|
Attributes associated with the file are set by setting the required
|
|
attribute bits in
|
|
.Em vap-\*[Gt]va_mask .
|
|
Attributes which are not being modified by
|
|
.Fn VOP_SETATTR
|
|
should be set to the value VNOVAL.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error is returned.
|
|
.Pp
|
|
For more information on vnode attributes see
|
|
.Xr vattr 9 .
|
|
.It Fn VOP_READ "vp" "uio" "ioflag" "cred"
|
|
Read the contents of a file.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to read from,
|
|
.Fa uio
|
|
is the location to read the data into,
|
|
.Fa ioflag
|
|
is a set of flags and
|
|
.Fa cred
|
|
are the credentials of the calling process.
|
|
.Pp
|
|
The
|
|
.Fa ioflag
|
|
argument is used to give directives and hints to the file system.
|
|
When attempting a read, the high 16 bits are used to provide a
|
|
read-ahead hint (in unit of file system blocks) that the file system
|
|
should attempt.
|
|
The low 16 bits are a bit mask which can contain the following flags:
|
|
.Pp
|
|
.Bl -tag -offset indent -width IO_ALTSEMANTICS -compact
|
|
.It IO_UNIT
|
|
do I/O as atomic unit
|
|
.It IO_APPEND
|
|
append write to end
|
|
.It IO_SYNC
|
|
sync I/O file integrity completion
|
|
.It IO_NODELOCKED
|
|
underlying node already locked
|
|
.It IO_NDELAY
|
|
FNDELAY flag set in file table
|
|
.It IO_DSYNC
|
|
sync I/O data integrity completion
|
|
.It IO_ALTSEMANTICS
|
|
use alternate I/O semantics
|
|
.It IO_NORMAL
|
|
operate on regular data
|
|
.It IO_EXT
|
|
operate on extended attributes
|
|
.It IO_DIRECT
|
|
do not buffer data in the kernel
|
|
.El
|
|
.Pp
|
|
Zero is returned on success, otherwise an error is returned.
|
|
The vnode should be locked on entry and remains locked on exit.
|
|
.It Fn VOP_WRITE "vp" "uio" "ioflag" "cred"
|
|
Write to a file.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to write to,
|
|
.Fa uio
|
|
is the location of the data to write,
|
|
.Fa ioflag
|
|
is a set of flags and
|
|
.Fa cred
|
|
are the credentials of the calling process.
|
|
.Pp
|
|
The
|
|
.Fa ioflag
|
|
argument is used to give directives and hints to the file system.
|
|
The low 16 bits are a bit mask which can contain the same flags as
|
|
.Fn VOP_READ .
|
|
.Pp
|
|
Zero is returned on success, otherwise an error is returned.
|
|
The vnode should be locked on entry and remains locked on exit.
|
|
.It Fn VOP_IOCTL "vp" "command" "data" "fflag" "cred" "l"
|
|
Perform device-specific I/O.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file, normally representing a device.
|
|
The argument
|
|
.Fa command
|
|
specifies the device-specific operation to perform and
|
|
.Fa cnp
|
|
provides extra data for the specified operation.
|
|
The argument
|
|
.Fa fflags
|
|
is a set of flags.
|
|
The argument
|
|
.Fa cred
|
|
is the caller's credentials and
|
|
.Fa l
|
|
the calling process.
|
|
If the operation is successful, zero is
|
|
returned, otherwise an appropriate error code is returned.
|
|
.Pp
|
|
Most file systems do not supply a function for
|
|
.Fn VOP_IOCTL .
|
|
This function implements the
|
|
.Xr ioctl 2
|
|
system call.
|
|
.It Fn VOP_FCNTL "vp" "command" "data" "fflag" "cred" "l"
|
|
Perform file control.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file.
|
|
The argument
|
|
.Fa command
|
|
specifies the operation to perform and
|
|
.Fa cnp
|
|
provides extra data for the specified operation.
|
|
The argument
|
|
.Fa fflags
|
|
is a set of flags.
|
|
The argument
|
|
.Fa cred
|
|
is the caller's credentials and
|
|
.Fa l
|
|
the calling process.
|
|
If the operation is successful, zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.It Fn VOP_POLL "vp" "events" "l"
|
|
Test if a poll event has occurred.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to poll and
|
|
.Fa l
|
|
is the calling process.
|
|
It returns any events of interest as specified by
|
|
.Fa events
|
|
that may have occurred for the file.
|
|
The argument
|
|
.Fa events
|
|
is a set of flags as specified by
|
|
.Xr poll 2 .
|
|
.It Fn VOP_KQFILTER "vp" "kn"
|
|
Register a knote
|
|
.Fa kn
|
|
with the vnode
|
|
.Fa vn .
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.It Fn VOP_REVOKE "vp" "flags"
|
|
Eliminate all activity associated with the vnode
|
|
.Fa vp .
|
|
The argument
|
|
.Fa flags
|
|
is a set of flags.
|
|
If REVOKEALL is set in
|
|
.Fa flags
|
|
all vnodes aliased to the vnode
|
|
.Fa vp
|
|
are also eliminated.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error is returned.
|
|
.It Fn VOP_MMAP "vp" "fflags" "cred" "l"
|
|
Map file into user address space.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file to map into an address space.
|
|
The argument
|
|
.Fa fflags
|
|
is a set of flags.
|
|
The argument
|
|
.Fa cred
|
|
is the caller's credentials and
|
|
.Fa l
|
|
the calling process requesting the map.
|
|
If the operation is successful, zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.Pp
|
|
Most file systems do not supply a function for
|
|
.Fn VOP_MMAP .
|
|
This function implements the
|
|
.Xr mmap 2
|
|
system call.
|
|
.It Fn VOP_FSYNC "vp" "cred" "flags" "offlo" "offhi" "l"
|
|
Flush pending data buffers for a file to disk.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file for flush.
|
|
The argument
|
|
.Fa cred
|
|
is the caller's credentials and
|
|
.Fa l
|
|
the calling process.
|
|
The argument
|
|
.Fa flags
|
|
is a set of flags.
|
|
If FSYNC_WAIT is specified in
|
|
.Fa flags ,
|
|
the function should wait for I/O to complete before returning.
|
|
The argument
|
|
.Fa offlo
|
|
and
|
|
.Fa offhi
|
|
specify the range of file to flush.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.Pp
|
|
This function implements the
|
|
.Xr sync 2
|
|
and
|
|
.Xr fsync 2
|
|
system calls.
|
|
.It Fn VOP_SEEK "vp" "oldoff" "newoff" "cred"
|
|
Test if the file is seekable for the specified offset
|
|
.Fa newoff .
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file to test.
|
|
For most filesystems this function simply tests if
|
|
.Fa newoff
|
|
is valid.
|
|
If the specified
|
|
.Fa newoff
|
|
is less than zero, the function returns error code EINVAL.
|
|
.It Fn VOP_REMOVE "dvp" "vp" "cnp"
|
|
Remove a file.
|
|
The argument
|
|
.Fa dvp
|
|
is the locked vnode of the directory to remove the file from and
|
|
.Fa vp
|
|
is the locked vnode of the file to remove.
|
|
The argument
|
|
.Fa cnp
|
|
is the pathname component about the file to remove.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
Both
|
|
.Fa dvp
|
|
and
|
|
.Fa vp
|
|
are locked on entry and are to be unlocked before returning.
|
|
.It Fn VOP_LINK "dvp" "vp" "cnp"
|
|
Link to a file.
|
|
The argument
|
|
.Fa dvp
|
|
is the locked node of the directory to create the new link and
|
|
.Fa vp
|
|
is the vnode of the file to be linked.
|
|
The argument
|
|
.Fa cnp
|
|
is the pathname component of the new link.
|
|
If the operation is successful zero is returned, otherwise an error
|
|
code is returned.
|
|
The directory vnode
|
|
.Fa dvp
|
|
should be locked on entry and will be released and unlocked on return.
|
|
The vnode
|
|
.Fa vp
|
|
should not be locked on entry and will remain unlocked on return.
|
|
.It Fn VOP_RENAME "fdvp" "fvp" "fcnp" "tdvp" "tvp" "tcnp"
|
|
Rename a file.
|
|
The argument
|
|
.Fa fdvp
|
|
is the vnode of the old parent directory containing in the file to be
|
|
renamed and
|
|
.Fa fvp
|
|
is the vnode of the file to be renamed.
|
|
The argument
|
|
.Fa fcnp
|
|
is the pathname component about the file to be renamed.
|
|
The argument
|
|
.Fa tdvp
|
|
is the vnode of the new directory of the target file and
|
|
.Fa tvp
|
|
is the vnode of the target file (if it exists).
|
|
The argument
|
|
.Fa tcnp
|
|
is the pathname component about the file's new name.
|
|
If the operation is successful zero is returned, otherwise and error
|
|
code is returned.
|
|
.Pp
|
|
The source directory and file vnodes should be unlocked and their
|
|
reference counts should be incremented before entry.
|
|
The target directory and file vnodes should both be locked on entry.
|
|
.Fn VOP_RENAME
|
|
updates the reference counts prior to returning.
|
|
.It Fn VOP_MKDIR "dvp" "vpp" "cnp" "vap"
|
|
Make a new directory in a given directory.
|
|
The argument
|
|
.Fa dvp
|
|
is the locked vnode of the directory to create the new directory in and
|
|
.Fa cnp
|
|
is the pathname component of the new directory.
|
|
The argument
|
|
.Fa vap
|
|
specifies the attributes that the new directory should be created
|
|
with.
|
|
If the file is successfully created, the address of the resulting
|
|
locked vnode is returned in
|
|
.Fa vpp
|
|
and zero is returned.
|
|
.Pp
|
|
This function is called after
|
|
.Fn VOP_LOOKUP
|
|
when a directory is being created.
|
|
Normally,
|
|
.Fn VOP_LOOKUP
|
|
will have set the SAVENAME flag in
|
|
.Em cnp-\*[Gt]cn_flags
|
|
to keep the memory pointed to by
|
|
.Em cnp-\*[Gt]cn_pnbuf
|
|
valid.
|
|
If an error is detected when creating the directory, this memory is
|
|
released.
|
|
If the directory is created successfully it will be released unless
|
|
the SAVESTART flags in specified in
|
|
.Em cnp-\*[Gt]cn_flags .
|
|
.It Fn VOP_RMDIR "dvp" "vp" "cnp"
|
|
Remove a directory in a given directory.
|
|
The argument
|
|
.Fa dvp
|
|
is the locked vnode of the directory to remove the directory from and
|
|
.Fa vp
|
|
is the locked vnode of the directory to remove.
|
|
The argument
|
|
.Fa cnp
|
|
is the pathname component of the directory.
|
|
Zero is returned on success, otherwise an error code is returned.
|
|
Both
|
|
.Fa dvp
|
|
and
|
|
.Fa vp
|
|
should be locked on entry and will be released and unlocked on return.
|
|
.It Fn VOP_SYMLINK "dvp" "vpp" "cnp" "vap" "target"
|
|
Create a symbolic link in a given directory.
|
|
The argument
|
|
.Fa dvp
|
|
is the locked vnode of the directory to create the symbolic link in
|
|
and
|
|
.Fa cnp
|
|
is the pathname component of the symbolic link.
|
|
The argument
|
|
.Fa vap
|
|
specifies the attributes that the symbolic link should be created
|
|
with and
|
|
.Fa target
|
|
specifies the pathname of the target of the symbolic link.
|
|
If the symbolic link is successfully created, the address of the
|
|
resulting locked vnode is returned in
|
|
.Fa vpp
|
|
and zero is returned.
|
|
.Pp
|
|
This function is called after
|
|
.Fn VOP_LOOKUP
|
|
when a symbolic link is being created.
|
|
Normally,
|
|
.Fn VOP_LOOKUP
|
|
will have set the SAVENAME flag in
|
|
.Em cnp-\*[Gt]cn_flags
|
|
to keep the memory pointed to by
|
|
.Em cnp-\*[Gt]cn_pnbuf
|
|
valid.
|
|
If an error is detected when creating the symbolic link, this memory
|
|
is released.
|
|
If the symbolic link is created successfully it will be released
|
|
unless the SAVESTART flags in specified in
|
|
.Em cnp-\*[Gt]cn_flags .
|
|
.It Fn VOP_READDIR "vp" "uio" "cred" "eofflag" "cookies" "ncookies"
|
|
Read directory entry.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the directory to read the contents of and
|
|
.Fa uio
|
|
is the destination location to read the contents into.
|
|
The argument
|
|
.Fa cred
|
|
is the caller's credentials.
|
|
The argument
|
|
.Fa eofflag
|
|
is the pointer to a flag which is set by
|
|
.Fn VOP_READDIR
|
|
to indicate an end-of-file condition.
|
|
If
|
|
.Fa eofflag
|
|
is
|
|
.Dv NULL ,
|
|
the end-of-file condition is not returned.
|
|
The arguments
|
|
.Fa cookies
|
|
and
|
|
.Fa ncookies
|
|
specify the addresses for the list and number of directory seek
|
|
cookies generated for NFS.
|
|
Both
|
|
.Fa cookies
|
|
and
|
|
.Fa ncookies
|
|
should be
|
|
.Dv NULL
|
|
if they aren't required to be returned by
|
|
.Fn VOP_READDIR .
|
|
The directory contents are read into struct dirent structures.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.Pp
|
|
The directory should be locked on entry and will remain locked on
|
|
return.
|
|
.Pp
|
|
If
|
|
.Fn VOP_READDIR
|
|
is called from the NFS server, the extra arguments
|
|
.Fa eofflag ,
|
|
.Fa ncookies
|
|
and
|
|
.Fa cookies
|
|
are used.
|
|
The value of
|
|
.Fa *eofflag
|
|
will be set to TRUE if the end of the directory is reached while
|
|
reading.
|
|
The directory seek cookies are returned to the NFS client and may be
|
|
used later to restart a directory read part way through the directory.
|
|
There should be one cookie returned per directory entry.
|
|
The value of the cookie should be the offset within the directory
|
|
where the on-disk version of the appropriate directory entry starts.
|
|
.It Fn VOP_READLINK "vp" "uio" "cred"
|
|
Read the contents of a symbolic link.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the symlink and
|
|
.Fa uio
|
|
is the destination location to read the contents into.
|
|
The argument
|
|
.Fa cred
|
|
is the credentials of the caller.
|
|
If the operation is successful zero is returned, otherwise an error
|
|
code is returned.
|
|
.Pp
|
|
The vnode should be locked on entry and will remain locked on return.
|
|
.It Fn VOP_ABORTOP "dvp" "cnp"
|
|
Abort pending operation on vnode
|
|
.Fa dvp .
|
|
This operation is rarely implemented in file systems.
|
|
.It Fn VOP_INACTIVE "vp" "l"
|
|
Release the inactive vnode.
|
|
.Fn VOP_INACTIVE
|
|
is called when the kernel is no longer using the vnode.
|
|
This may be because the reference count reaches zero or it may be that
|
|
the file system is being forcibly unmounted while there are open
|
|
files.
|
|
It can be used to reclaim space for open but deleted files.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode to be released.
|
|
The argument
|
|
.Fa l
|
|
is the calling process.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
The vnode
|
|
.Fa vp
|
|
must be locked on entry, and will be unlocked on return.
|
|
.It Fn VOP_RECLAIM "vp" "l"
|
|
Reclaim the vnode for another file system.
|
|
.Fn VOP_RECLAIM
|
|
is called when a vnode is being reused for a different file system.
|
|
Any file system specific resources associated with the vnode should be
|
|
freed.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode to be reclaimed.
|
|
The argument
|
|
.Fa l
|
|
is the calling process.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
The vnode
|
|
.Fa vp
|
|
should not be locked on entry, and will remain unlocked on return.
|
|
.It Fn VOP_LOCK "vp" "flags"
|
|
Sleep until vnode lock is free.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to be locked.
|
|
The argument
|
|
.Fa flags
|
|
is a set of
|
|
.Xr lockmgr 9
|
|
flags.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.Fn VOP_LOCK
|
|
is used to serialise access to the file system such as to present two
|
|
writes to the same file from happening at the same time.
|
|
Kernel code should use
|
|
.Xr vn_lock 9
|
|
to lock a vnode rather than calling
|
|
.Fn VOP_LOCK
|
|
directly.
|
|
.It Fn VOP_UNLOCK "vp" "flags"
|
|
Wake up process sleeping on lock.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode of the file to be unlocked.
|
|
The argument
|
|
.Fa flags
|
|
is a set of
|
|
.Xr lockmgr 9
|
|
flags.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.Fn VOP_UNLOCK
|
|
is used to serialise access to the file system such as to present two
|
|
writes to the same file from happening at the same time.
|
|
.It Fn VOP_ISLOCKED "vp"
|
|
Test if the vnode
|
|
.Fa vp
|
|
is locked.
|
|
A non-zero values is returned if the vnode is not locked, otherwise
|
|
zero is returned.
|
|
.It Fn VOP_BMAP "vp" "bn" "vpp" "bnp" "runp"
|
|
Convert the logical block number
|
|
.Fa bn
|
|
of a file specified by vnode
|
|
.Fa vp
|
|
to its physical block number on the disk.
|
|
If
|
|
.Fa vpp
|
|
is not
|
|
.Dv NULL ,
|
|
the vnode of the device vnode for the file system is
|
|
returned in the address specified by
|
|
.Fa vpp .
|
|
If
|
|
.Fa runp
|
|
is not
|
|
.Dv NULL ,
|
|
the maximum blocksize is returned in the address specified by
|
|
.Fa runp .
|
|
.It Fn VOP_PRINT "vp"
|
|
Print debugging information.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode to print.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.It Fn VOP_PATHCONF "vp" "name" "retval"
|
|
Implement POSIX
|
|
.Xr pathconf 2
|
|
and
|
|
.Xr fpathconf 2
|
|
support.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode to get information about.
|
|
The argument
|
|
.Fa name
|
|
specified the type of information to return.
|
|
The information is returned in the address specified by
|
|
.Fa retval .
|
|
Valid values for
|
|
.Fa name
|
|
are:
|
|
.Pp
|
|
.Bl -tag -offset indent -width _PC_CHOWN_RESTRICTED -compact
|
|
.It _PC_LINK_MAX
|
|
return the maximum number of links to a file
|
|
.It _PC_NAME_MAX
|
|
return the maximum number of bytes in a file name
|
|
.It _PC_PATH_MAX
|
|
return the maximum number of bytes in a pathname
|
|
.It _PC_PIPE_BUF
|
|
return the maximum number of bytes which will be written atomically to
|
|
a pipe
|
|
.It _PC_CHOWN_RESTRICTED
|
|
return 1 if appropriate privileges are required for the
|
|
.Xr chown 2
|
|
system call, otherwise zero
|
|
.It _PC_NO_TRUNC
|
|
return if file names longer than KERN_NAME_MAX are truncated
|
|
.El
|
|
.Pp
|
|
If
|
|
.Fa name
|
|
is recognised,
|
|
.Fa *retval
|
|
is set to the specified value and zero is returned, otherwise an
|
|
appropriate error is returned.
|
|
.It Fn VOP_ADVLOCK "vp" "id" "op" "fl" "flags"
|
|
Manipulate Advisory record locks on a vnode.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode on which locks are manipulated.
|
|
The argument
|
|
.Fa id
|
|
is the id token which is changing the lock and
|
|
.Fa op
|
|
is the
|
|
.Xr fcntl 2
|
|
operation to perform.
|
|
Valid values are:
|
|
.Pp
|
|
.Bl -tag -offset indent -width F_UNLCK -compact
|
|
.It F_SETLK
|
|
set lock
|
|
.It F_GETLK
|
|
get the first conflicted lock
|
|
.It F_UNLCK
|
|
clear lock
|
|
.El
|
|
.Pp
|
|
The argument
|
|
.Fa fl
|
|
is a description of the lock.
|
|
In the case of
|
|
.Dv SEEK_CUR ,
|
|
The caller should add the current file offset to
|
|
fl-\*[Gt]l_start beforehand.
|
|
.Fn VOP_ADVLOCK
|
|
treats
|
|
.Dv SEEK_CUR
|
|
as
|
|
.Dv SEEK_SET .
|
|
.Pp
|
|
The argument
|
|
.Fa flags
|
|
is the set of flags.
|
|
Valid values are:
|
|
.Pp
|
|
.Bl -tag -offset indent -width F_FLOCK -compact
|
|
.It F_WAIT
|
|
wait until lock is granted
|
|
.It F_FLOCK
|
|
use
|
|
.Xr flock 2
|
|
semantics for lock
|
|
.It F_POSIX
|
|
use POSIX semantics for lock
|
|
.El
|
|
.Pp
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error is returned.
|
|
.It Fn VOP_LEASE "vp" "l" "cred" "flags"
|
|
Validate vnode credentials and operation type.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file to validate credentials
|
|
.Fa cred .
|
|
The argument
|
|
.Fa l
|
|
specifies the calling process and
|
|
.Fa flags
|
|
specifies the operation flags.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
The vnode must be locked on entry and remains locked on return.
|
|
.It Fn VOP_WHITEOUT "dvp" "cnp" "flags"
|
|
Whiteout pathname component in directory with vnode
|
|
.Fa dvp .
|
|
The argument
|
|
.Fa cnp
|
|
specifies the pathname component to whiteout.
|
|
.It Fn VOP_GETPAGES "vp" "offset" "m" "count" "centeridx" "access_type" "advice" "flags"
|
|
Read VM pages from file.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode to read the VM pages from.
|
|
The argument
|
|
.Fa offset
|
|
is offset in the file to start accessing and
|
|
.Fa m
|
|
is an array of VM pages.
|
|
The argument
|
|
.Fa count
|
|
points a variable that specifies the number of pages to read.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
If PGO_LOCKED is specified in
|
|
.Em flags ,
|
|
.Fn VOP_GETPAGES
|
|
might return less pages than requested.
|
|
In that case, the variable pointed to by
|
|
.Em count
|
|
will be updated.
|
|
.Pp
|
|
This function is primarily used by the page-fault handing mechanism.
|
|
.It Fn VOP_PUTPAGES "vp" "offlo" "offhi" "flags"
|
|
Write modified (dirty) VM pages to file.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode to write the VM pages to.
|
|
The vnode's vm object lock
|
|
.Va ( v_uobj.vmobjlock )
|
|
must be held by the caller and will be released upon return.
|
|
The arguments
|
|
.Fa offlo
|
|
and
|
|
.Fa offhi
|
|
specify the range of VM pages to write.
|
|
In case
|
|
.Fa offhi
|
|
is given as 0, all pages at and after the start offset
|
|
.Fa offlo
|
|
belonging the vnode
|
|
.Fa vp
|
|
will be written.
|
|
The argument
|
|
.Fa flags
|
|
controls the behaviour of the routine and takes the vm pager's
|
|
flags
|
|
.Dv ( PGO_ -prefixed).
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.Pp
|
|
The function is primarily used by the pageout handling mechanism and
|
|
is commonly implemented indirectly
|
|
by
|
|
.Fn genfs_putpages
|
|
with the help of
|
|
.Fn VOP_STRATEGY
|
|
and
|
|
.Fn VOP_BMAP .
|
|
.It Fn VOP_STRATEGY "vp" "bp"
|
|
Read/write a file system buffer.
|
|
The argument
|
|
.Fa vp
|
|
is the vnode to read/write to.
|
|
The argument
|
|
.Fa bp
|
|
is the buffer to be read or written.
|
|
.Fn VOP_STRATEGY
|
|
will either read or write data to the file depending on the value of
|
|
.Em bp-\*[Gt]b_flags .
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.It Fn VOP_BWRITE "bp"
|
|
Write a file system buffer.
|
|
The argument
|
|
.Fa bp
|
|
specifies the buffer to be written.
|
|
If the operation is successful zero is returned, otherwise an
|
|
appropriate error code is returned.
|
|
.It Fn VOP_GETEXTATTR "vp" "attrnamespace" "name" "uio" "size" "cred" "l"
|
|
Get an extended attribute.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file or directory from which to retrieve the
|
|
attribute.
|
|
The argument
|
|
.Fa attrnamespace
|
|
specifies the extended attribute namespace.
|
|
The argument
|
|
.Fa name
|
|
is a nul-terminated character string naming the attribute to retrieve.
|
|
The argument
|
|
.Fa uio ,
|
|
if not
|
|
.Dv NULL ,
|
|
specifies where the extended attribute value is to be written.
|
|
The argument
|
|
.Fa size ,
|
|
if not
|
|
.Dv NULL ,
|
|
will contain the number of bytes required to read all of
|
|
the attribute data upon return.
|
|
In most cases,
|
|
.Fa uio
|
|
will be
|
|
.Dv NULL
|
|
when
|
|
.Fa size
|
|
is not, and vice versa.
|
|
The argument
|
|
.Fa cred
|
|
specifies the user credentials to use when authorizing the request.
|
|
The argument
|
|
.Fa l
|
|
specifies the process requesting the extended attribute.
|
|
.It Fn VOP_SETEXTATTR "vp" "attrnamespace" "name" "uio" "cred" "l"
|
|
Set an extended attribute.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file or directory to which to store the
|
|
attribute.
|
|
The argument
|
|
.Fa namespace
|
|
specifies the extended attribute namespace.
|
|
The argument
|
|
.Fa name
|
|
is a nul-terminated character string naming the attribute to store.
|
|
The argument
|
|
.Fa uio
|
|
specifies the source of the extended attribute data.
|
|
The argument
|
|
.Fa cred
|
|
specifies the user credentials to use when authorizing the request.
|
|
The argument
|
|
.Fa l
|
|
specifies the process setting the extended attribute.
|
|
.It Fn VOP_LISTEXTATTR "vp" "attrnamespace" "uio" "size" "cred" "l"
|
|
Retrieve the list of extended attributes.
|
|
The argument
|
|
.Fa vp
|
|
is the locked vnode of the file or directory whose attributes are to be listed.
|
|
The argument
|
|
.Fa attrnamespace
|
|
specifies the extended attribute namespace.
|
|
The argument
|
|
.Fa uio ,
|
|
if not
|
|
.Dv NULL ,
|
|
specifies where the extended attribute list is to be written.
|
|
The argument
|
|
.Fa size ,
|
|
if not
|
|
.Dv NULL ,
|
|
will contain the number of bytes required to read all of
|
|
the attribute names upon return.
|
|
In most cases,
|
|
.Fa uio
|
|
will be
|
|
.Dv NULL
|
|
when
|
|
.Fa size
|
|
is not, and vice versa.
|
|
The argument
|
|
.Fa cred
|
|
specifies the user credentials to use when authorizing the request.
|
|
The argument
|
|
.Fa l
|
|
specifies the process requesting the extended attribute list.
|
|
.El
|
|
.Sh ERRORS
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOATTR
|
|
The requested attribute is not defined for this vnode.
|
|
.It Bq Er ENOTDIR
|
|
The vnode does not represent a directory.
|
|
.It Bq Er ENOENT
|
|
The component was not found in the directory.
|
|
.It Bq Er ENOSPC
|
|
The file system is full.
|
|
.It Bq Er EDQUOT
|
|
Quota exceeded.
|
|
.It Bq Er EACCES
|
|
Access for the specified operation is denied.
|
|
.It Bq Er EJUSTRETURN
|
|
A CREATE or RENAME operation would be successful.
|
|
.It Bq Er EPERM
|
|
an attempt was made to change an immutable file
|
|
.It Bq Er ENOTEMPTY
|
|
attempt to remove a directory which is not empty
|
|
.It Bq Er EINVAL
|
|
attempt to read from an illegal offset in the directory; unrecognised
|
|
input
|
|
.It Bq Er EIO
|
|
a read error occurred while reading the directory or reading the
|
|
contents of a symbolic link
|
|
.It Bq Er EROFS
|
|
the filesystem is read-only
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr extattr 9 ,
|
|
.Xr intro 9 ,
|
|
.Xr lock 9 ,
|
|
.Xr namei 9 ,
|
|
.Xr vattr 9 ,
|
|
.Xr vfs 9 ,
|
|
.Xr vfsops 9 ,
|
|
.Xr vnode 9
|
|
.Sh HISTORY
|
|
The vnode operations vector, its functions and the corresponding
|
|
macros appeared in
|
|
.Bx 4.3 .
|