lockd.8c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 8C 代码 · 共 74 行

.TH lockd 8c
.SH Name
lockd \- network lock daemon
.SH Syntax
.B /usr/etc/lockd 
[
.B \-t
.I timeout
] 
[
.B \-g
.I graceperiod
]
.NXR "lock" "daemon"
.NXR "network" "lock daemon"
.SH Description
The
.PN lockd
daemon processes lock requests that are either
sent locally by the kernel or remotely by another lock daemon.
The NFS locking service makes this advisory locking support
possible by using the
.PN fcntl
system call and the
.PN lockf
subroutine.
The
.PN lockd 
daemon forwards lock requests for remote data to the server site's 
lock daemon.
The
.PN lockd 
daemon then requests the status monitor daemon,
.PN statd ,
for monitor service.
The reply to the lock request is not sent 
to the kernel until 
the status daemon and the server site's
lock daemon have replied.
.PP
If either the 
status monitor or server site's lock daemon is unavailable,
the reply to a lock request for remote data 
is delayed until all daemons become available. 
.PP
When a server recovers, it waits for a grace period for all client site
.PN lockd
daemons to submit reclaim requests.  Client site
.PN lockd
daemons are notified by
.PN statd
of the server recovery and promptly resubmit previously
granted lock requests.  If a client site's
.PN lockd
daemon fails to secure previously granted locks at the server site, the
.PN lockd
daemon sends the signal SIGLOST  
to all the processes that were previously holding locks 
and cannot reclaim them.
.SH Options
.IP "\fB\-t \fItimeout\fR" 16
The
.PN lockd
daemon uses \fItimeout\fP (in seconds) as the interval 
instead of the default value of 15 seconds to retransmit a lock
request to the remote server.
.IP "\fB\-g \fIgraceperiod\fR"
The
.PN lockd
daemon uses \fIgraceperiod\fP (in seconds) as the grace period duration
instead of the default value of 45 seconds.
.SH See Also
fcntl(2), lockf(3), signal(3), statd(8c)