1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Scooter Morris at Genentech Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)lockf.h 8.1 (Berkeley) 6/11/93 35 * $FreeBSD$ 36 */ 37 38 #ifndef _SYS_LOCKF_H_ 39 #define _SYS_LOCKF_H_ 40 41 #include <sys/queue.h> 42 #include <sys/_lock.h> 43 #include <sys/_sx.h> 44 45 struct flock; 46 struct vop_advlock_args; 47 struct vop_advlockasync_args; 48 49 /* 50 * The lockf_entry structure is a kernel structure which contains the 51 * information associated with a byte range lock. The lockf_entry 52 * structures are linked into the inode structure. Locks are sorted by 53 * the starting byte of the lock for efficiency. 54 * 55 * Active and pending locks on a vnode are organised into a 56 * graph. Each pending lock has an out-going edge to each active lock 57 * that blocks it. 58 * 59 * Locks: 60 * (i) locked by the vnode interlock 61 * (s) locked by state->ls_lock 62 * (S) locked by lf_lock_states_lock 63 * (c) const until freeing 64 */ 65 struct lockf_edge { 66 LIST_ENTRY(lockf_edge) le_outlink; /* (s) link from's out-edge list */ 67 LIST_ENTRY(lockf_edge) le_inlink; /* (s) link to's in-edge list */ 68 struct lockf_entry *le_from; /* (c) out-going from here */ 69 struct lockf_entry *le_to; /* (s) in-coming to here */ 70 }; 71 LIST_HEAD(lockf_edge_list, lockf_edge); 72 73 struct lockf_entry { 74 short lf_flags; /* (c) Semantics: F_POSIX, F_FLOCK, F_WAIT */ 75 short lf_type; /* (s) Lock type: F_RDLCK, F_WRLCK */ 76 off_t lf_start; /* (s) Byte # of the start of the lock */ 77 off_t lf_end; /* (s) Byte # of the end of the lock (OFF_MAX=EOF) */ 78 struct lock_owner *lf_owner; /* (c) Owner of the lock */ 79 struct vnode *lf_vnode; /* (c) File being locked (only valid for active lock) */ 80 struct inode *lf_inode; /* (c) Back pointer to the inode */ 81 struct task *lf_async_task;/* (c) Async lock callback */ 82 LIST_ENTRY(lockf_entry) lf_link; /* (s) Linkage for lock lists */ 83 struct lockf_edge_list lf_outedges; /* (s) list of out-edges */ 84 struct lockf_edge_list lf_inedges; /* (s) list of in-edges */ 85 int lf_refs; /* (s) ref count */ 86 }; 87 LIST_HEAD(lockf_entry_list, lockf_entry); 88 89 /* 90 * Extra lf_flags bits used by the implementation 91 */ 92 #define F_INTR 0x8000 /* lock was interrupted by lf_purgelocks */ 93 94 /* 95 * Filesystem private node structures should include space for a 96 * pointer to a struct lockf_state. This pointer is used by the lock 97 * manager to track the locking state for a file. 98 * 99 * The ls_active list contains the set of active locks on the file. It 100 * is strictly ordered by the lock's lf_start value. Each active lock 101 * will have in-coming edges to any pending lock which it blocks. 102 * 103 * Lock requests which are blocked by some other active lock are 104 * listed in ls_pending with newer requests first in the list. Lock 105 * requests in this list will have out-going edges to each active lock 106 * that blocks then. They will also have out-going edges to each 107 * pending lock that is older in the queue - this helps to ensure 108 * fairness when several processes are contenting to lock the same 109 * record. 110 111 * The value of ls_threads is the number of threads currently using 112 * the state structure (typically either setting/clearing locks or 113 * sleeping waiting to do so). This is used to defer freeing the 114 * structure while some thread is still using it. 115 */ 116 struct lockf { 117 LIST_ENTRY(lockf) ls_link; /* (S) all active lockf states */ 118 struct sx ls_lock; 119 struct lockf_entry_list ls_active; /* (s) Active locks */ 120 struct lockf_entry_list ls_pending; /* (s) Pending locks */ 121 int ls_threads; /* (i) Thread count */ 122 }; 123 LIST_HEAD(lockf_list, lockf); 124 125 typedef int lf_iterator(struct vnode *, struct flock *, void *); 126 127 int lf_advlock(struct vop_advlock_args *, struct lockf **, u_quad_t); 128 int lf_advlockasync(struct vop_advlockasync_args *, struct lockf **, u_quad_t); 129 void lf_purgelocks(struct vnode *vp, struct lockf **statep); 130 int lf_iteratelocks_sysid(int sysid, lf_iterator *, void *); 131 int lf_iteratelocks_vnode(struct vnode *vp, lf_iterator *, void *); 132 int lf_countlocks(int sysid); 133 void lf_clearremotesys(int sysid); 134 135 #endif /* !_SYS_LOCKF_H_ */ 136