151 lines
3.7 KiB
Groff
151 lines
3.7 KiB
Groff
.\" -*- nroff -*-
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.\"
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.\" Copyright (c) 1996 Doug Rabson
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.\"
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.\" All rights reserved.
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.\"
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.\" This program is free software.
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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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 24, 1996
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.Os
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.Dt VOP_FSYNC 9
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.Sh NAME
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.Nm VOP_FSYNC
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.Nd flush filesystem buffers for a file
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.Sh SYNOPSIS
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.Fd #include <sys/param.h>
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.Fd #include <sys/vnode.h>
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.Ft int
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.Fn VOP_FSYNC "struct vnode *vp" "struct ucred *cred" "int waitfor" "struct proc *p"
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.Sh DESCRIPTION
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This call flushes any dirty filesystem buffers for the file.
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It is used to implement the
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.Xr sync 2
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and
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.Xr fsync 2
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system calls.
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.Pp
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Its arguments are:
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.Bl -tag -width waitfor
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.It Ar vp
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the vnode of the file
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.It Ar cred
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the caller's credentials
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.It Ar waitfor
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whether the function should wait for I/O to complete.
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Possible values are:
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.Bl -tag -width MNT_NOWAIT
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.It Dv MNT_WAIT
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synchronously wait for I/O to complete
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.It Dv MNT_NOWAIT
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start all I/O, but do not wait for it
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.It Dv MNT_LAZY
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push data not written by filesystem syncer
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.El
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.It Ar p
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the calling process
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.El
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.Pp
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The argument
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.Fa waitfor
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is either
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.Dv MNT_WAIT
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or
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.Dv MNT_NOWAIT
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and specifies whether or not the function should wait for the writes
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to finish before returning.
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.Sh LOCKS
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The file should be locked on entry.
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.Sh RETURN VALUES
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Zero is returned if the call is successful, otherwise an appropriate
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error code is returned.
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.Sh PSEUDOCODE
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.Bd -literal
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int
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vop_fsync(struct vnode *vp, struct ucred *cred, int waitfor, struct proc *p)
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{
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struct buf *bp;
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struct buf *nbp;
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struct timeval tv;
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int s;
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loop:
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s = splbio();
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for (bp = vp->v_dirtyblkhd.lh_first; bp; bp = nbp) {
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nbp = bp->b_vnbufs.le_next;
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/*
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* Ignore buffers which are already being written.
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*/
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if (bp->b_flags & B_BUSY)
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continue;
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/*
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* Make sure the buffer is dirty.
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*/
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if ((bp->b_flags & B_DELWRI) == 0)
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panic("vop_fsync: not dirty");
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vfs_bio_awrite(bp);
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splx(s);
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goto loop;
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}
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splx(s);
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if (waitfor == MNT_WAIT) {
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s = splbio();
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while (vp->v_numoutput) {
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vp->v_flag |= VBWAIT;
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tsleep((caddr_t)&vp->v_numoutput, PRIBIO + 1, "vopfsn");
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}
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splx(s);
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#ifdef DIAGNOSTIC
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if (vp->v_dirtyblkhd.lh_first) {
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vprint("vop_fsync: dirty", vp);
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goto loop;
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}
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#endif
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}
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/*
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* Write out the on-disc version of the vnode.
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*/
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tv = time;
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return VOP_UPDATE(vp, &tv, &tv, waitfor == MNT_WAIT);
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}
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.Ed
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er ENOSPC
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The filesystem is full.
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.It Bq Er EDQUOT
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Quota exceeded.
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.El
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.Sh SEE ALSO
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.Xr vnode 9
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.Sh AUTHORS
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This man page was written by
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.An Doug Rabson .
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