/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Scooter Morris at Genentech Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)lockf.h 8.1 (Berkeley) 6/11/93
* $FreeBSD$
*/
#ifndef _SYS_LOCKF_H_
#define _SYS_LOCKF_H_
#include <sys/queue.h>
#include <sys/_lock.h>
#include <sys/_sx.h>
struct flock;
struct vop_advlock_args;
struct vop_advlockasync_args;
/*
* The lockf_entry structure is a kernel structure which contains the
* information associated with a byte range lock. The lockf_entry
* structures are linked into the inode structure. Locks are sorted by
* the starting byte of the lock for efficiency.
*
* Active and pending locks on a vnode are organised into a
* graph. Each pending lock has an out-going edge to each active lock
* that blocks it.
*
* Locks:
* (i) locked by the vnode interlock
* (s) locked by state->ls_lock
* (S) locked by lf_lock_states_lock
* (c) const until freeing
*/
struct lockf_edge {
LIST_ENTRY(lockf_edge) le_outlink; /* (s) link from's out-edge list */
LIST_ENTRY(lockf_edge) le_inlink; /* (s) link to's in-edge list */
struct lockf_entry *le_from; /* (c) out-going from here */
struct lockf_entry *le_to; /* (s) in-coming to here */
};
LIST_HEAD(lockf_edge_list, lockf_edge);
struct lockf_entry {
short lf_flags; /* (c) Semantics: F_POSIX, F_FLOCK, F_WAIT */
short lf_type; /* (s) Lock type: F_RDLCK, F_WRLCK */
off_t lf_start; /* (s) Byte # of the start of the lock */
off_t lf_end; /* (s) Byte # of the end of the lock (OFF_MAX=EOF) */
struct lock_owner *lf_owner; /* (c) Owner of the lock */
struct vnode *lf_vnode; /* (c) File being locked (only valid for active lock) */
struct inode *lf_inode; /* (c) Back pointer to the inode */
struct task *lf_async_task;/* (c) Async lock callback */
LIST_ENTRY(lockf_entry) lf_link; /* (s) Linkage for lock lists */
struct lockf_edge_list lf_outedges; /* (s) list of out-edges */
struct lockf_edge_list lf_inedges; /* (s) list of in-edges */
int lf_refs; /* (s) ref count */
};
LIST_HEAD(lockf_entry_list, lockf_entry);
/*
* Extra lf_flags bits used by the implementation
*/
#define F_INTR 0x8000 /* lock was interrupted by lf_purgelocks */
/*
* Filesystem private node structures should include space for a
* pointer to a struct lockf_state. This pointer is used by the lock
* manager to track the locking state for a file.
*
* The ls_active list contains the set of active locks on the file. It
* is strictly ordered by the lock's lf_start value. Each active lock
* will have in-coming edges to any pending lock which it blocks.
*
* Lock requests which are blocked by some other active lock are
* listed in ls_pending with newer requests first in the list. Lock
* requests in this list will have out-going edges to each active lock
* that blocks then. They will also have out-going edges to each
* pending lock that is older in the queue - this helps to ensure
* fairness when several processes are contenting to lock the same
* record.
* The value of ls_threads is the number of threads currently using
* the state structure (typically either setting/clearing locks or
* sleeping waiting to do so). This is used to defer freeing the
* structure while some thread is still using it.
*/
struct lockf {
LIST_ENTRY(lockf) ls_link; /* (S) all active lockf states */
struct sx ls_lock;
struct lockf_entry_list ls_active; /* (s) Active locks */
struct lockf_entry_list ls_pending; /* (s) Pending locks */
int ls_threads; /* (i) Thread count */
};
LIST_HEAD(lockf_list, lockf);
typedef int lf_iterator(struct vnode *, struct flock *, void *);
int lf_advlock(struct vop_advlock_args *, struct lockf **, u_quad_t);
int lf_advlockasync(struct vop_advlockasync_args *, struct lockf **, u_quad_t);
void lf_purgelocks(struct vnode *vp, struct lockf **statep);
int lf_iteratelocks_sysid(int sysid, lf_iterator *, void *);
int lf_iteratelocks_vnode(struct vnode *vp, lf_iterator *, void *);
int lf_countlocks(int sysid);
void lf_clearremotesys(int sysid);
#endif /* !_SYS_LOCKF_H_ */
