134 lines
5.5 KiB
C
134 lines
5.5 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Scooter Morris at Genentech Inc.
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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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* 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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* @(#)lockf.h 8.1 (Berkeley) 6/11/93
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* $FreeBSD$
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*/
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#ifndef _SYS_LOCKF_H_
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#define _SYS_LOCKF_H_
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#include <sys/queue.h>
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#include <sys/_lock.h>
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#include <sys/_sx.h>
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struct flock;
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struct vop_advlock_args;
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struct vop_advlockasync_args;
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/*
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* The lockf_entry structure is a kernel structure which contains the
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* information associated with a byte range lock. The lockf_entry
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* structures are linked into the inode structure. Locks are sorted by
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* the starting byte of the lock for efficiency.
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*
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* Active and pending locks on a vnode are organised into a
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* graph. Each pending lock has an out-going edge to each active lock
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* that blocks it.
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*
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* Locks:
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* (i) locked by the vnode interlock
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* (s) locked by state->ls_lock
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* (S) locked by lf_lock_states_lock
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* (c) const until freeing
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*/
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struct lockf_edge {
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LIST_ENTRY(lockf_edge) le_outlink; /* (s) link from's out-edge list */
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LIST_ENTRY(lockf_edge) le_inlink; /* (s) link to's in-edge list */
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struct lockf_entry *le_from; /* (c) out-going from here */
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struct lockf_entry *le_to; /* (s) in-coming to here */
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};
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LIST_HEAD(lockf_edge_list, lockf_edge);
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struct lockf_entry {
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short lf_flags; /* (c) Semantics: F_POSIX, F_FLOCK, F_WAIT */
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short lf_type; /* (s) Lock type: F_RDLCK, F_WRLCK */
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off_t lf_start; /* (s) Byte # of the start of the lock */
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off_t lf_end; /* (s) Byte # of the end of the lock (OFF_MAX=EOF) */
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struct lock_owner *lf_owner; /* (c) Owner of the lock */
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struct vnode *lf_vnode; /* (c) File being locked (only valid for active lock) */
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struct inode *lf_inode; /* (c) Back pointer to the inode */
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struct task *lf_async_task;/* (c) Async lock callback */
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LIST_ENTRY(lockf_entry) lf_link; /* (s) Linkage for lock lists */
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struct lockf_edge_list lf_outedges; /* (s) list of out-edges */
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struct lockf_edge_list lf_inedges; /* (s) list of out-edges */
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int lf_refs; /* (s) ref count */
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};
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LIST_HEAD(lockf_entry_list, lockf_entry);
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/*
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* Extra lf_flags bits used by the implementation
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*/
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#define F_INTR 0x8000 /* lock was interrupted by lf_purgelocks */
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/*
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* Filesystem private node structures should include space for a
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* pointer to a struct lockf_state. This pointer is used by the lock
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* manager to track the locking state for a file.
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*
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* The ls_active list contains the set of active locks on the file. It
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* is strictly ordered by the lock's lf_start value. Each active lock
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* will have in-coming edges to any pending lock which it blocks.
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*
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* Lock requests which are blocked by some other active lock are
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* listed in ls_pending with newer requests first in the list. Lock
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* requests in this list will have out-going edges to each active lock
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* that blocks then. They will also have out-going edges to each
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* pending lock that is older in the queue - this helps to ensure
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* fairness when several processes are contenting to lock the same
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* record.
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* The value of ls_threads is the number of threads currently using
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* the state structure (typically either setting/clearing locks or
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* sleeping waiting to do so). This is used to defer freeing the
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* structure while some thread is still using it.
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*/
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struct lockf {
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LIST_ENTRY(lockf) ls_link; /* (S) all active lockf states */
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struct sx ls_lock;
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struct lockf_entry_list ls_active; /* (s) Active locks */
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struct lockf_entry_list ls_pending; /* (s) Pending locks */
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int ls_threads; /* (i) Thread count */
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};
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LIST_HEAD(lockf_list, lockf);
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typedef int lf_iterator(struct vnode *, struct flock *, void *);
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int lf_advlock(struct vop_advlock_args *, struct lockf **, u_quad_t);
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int lf_advlockasync(struct vop_advlockasync_args *, struct lockf **, u_quad_t);
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void lf_purgelocks(struct vnode *vp, struct lockf **statep);
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int lf_iteratelocks_sysid(int sysid, lf_iterator *, void *);
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int lf_iteratelocks_vnode(struct vnode *vp, lf_iterator *, void *);
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int lf_countlocks(int sysid);
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void lf_clearremotesys(int sysid);
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#endif /* !_SYS_LOCKF_H_ */
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