7e6cabd06e
Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
78 lines
2.5 KiB
Groff
78 lines
2.5 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
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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. 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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.\" @(#)sync.2 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd June 4, 1993
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.Dt SYNC 2
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.Os
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.Sh NAME
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.Nm sync
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.Nd "schedule file system updates"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft void
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.Fn sync void
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.Sh DESCRIPTION
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The
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.Fn sync
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system call forces a write of dirty (modified) buffers
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in the block buffer cache out
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to disk.
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The kernel keeps this information in core to reduce
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the number of disk I/O transfers required by the system.
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As information in the cache is lost after a system crash, a
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.Fn sync
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system call is issued
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frequently
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by the kernel process
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.Xr syncer 4
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(about every 30 seconds).
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.Pp
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The
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.Xr fsync 2
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system call
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may be used to synchronize individual file descriptor
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attributes.
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.Sh SEE ALSO
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.Xr fsync 2 ,
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.Xr syncer 4 ,
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.Xr sync 8
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.Sh HISTORY
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The
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.Fn sync
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function appeared in
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.At v6 .
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.Sh BUGS
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The
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.Fn sync
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system call
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may return before the buffers are completely flushed.
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