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 35 #ifndef _SYS_LOCKF_H_ 36 #define _SYS_LOCKF_H_ 37 38 #include <sys/queue.h> 39 #include <sys/_lock.h> 40 #include <sys/_sx.h> 41 42 struct flock; 43 struct vop_advlock_args; 44 struct vop_advlockasync_args; 45 46 /* 47 * The lockf_entry structure is a kernel structure which contains the 48 * information associated with a byte range lock. The lockf_entry 49 * structures are linked into the inode structure. Locks are sorted by 50 * the starting byte of the lock for efficiency. 51 * 52 * Active and pending locks on a vnode are organised into a 53 * graph. Each pending lock has an out-going edge to each active lock 54 * that blocks it. 55 * 56 * Locks: 57 * (i) locked by the vnode interlock 58 * (s) locked by state->ls_lock 59 * (S) locked by lf_lock_states_lock 60 * (c) const until freeing 61 */ 62 struct lockf_edge { 63 LIST_ENTRY(lockf_edge) le_outlink; /* (s) link from's out-edge list */ 64 LIST_ENTRY(lockf_edge) le_inlink; /* (s) link to's in-edge list */ 65 struct lockf_entry *le_from; /* (c) out-going from here */ 66 struct lockf_entry *le_to; /* (s) in-coming to here */ 67 }; 68 LIST_HEAD(lockf_edge_list, lockf_edge); 69 70 struct lockf_entry { 71 short lf_flags; /* (c) Semantics: F_POSIX, F_FLOCK, F_WAIT */ 72 short lf_type; /* (s) Lock type: F_RDLCK, F_WRLCK */ 73 off_t lf_start; /* (s) Byte # of the start of the lock */ 74 off_t lf_end; /* (s) Byte # of the end of the lock (OFF_MAX=EOF) */ 75 struct lock_owner *lf_owner; /* (c) Owner of the lock */ 76 struct vnode *lf_vnode; /* (c) File being locked (only valid for active lock) */ 77 struct task *lf_async_task;/* (c) Async lock callback */ 78 LIST_ENTRY(lockf_entry) lf_link; /* (s) Linkage for lock lists */ 79 struct lockf_edge_list lf_outedges; /* (s) list of out-edges */ 80 struct lockf_edge_list lf_inedges; /* (s) list of in-edges */ 81 int lf_refs; /* (s) ref count */ 82 }; 83 LIST_HEAD(lockf_entry_list, lockf_entry); 84 85 /* 86 * Extra lf_flags bits used by the implementation 87 */ 88 #define F_INTR 0x8000 /* lock was interrupted by lf_purgelocks */ 89 90 /* 91 * Filesystem private node structures should include space for a 92 * pointer to a struct lockf_state. This pointer is used by the lock 93 * manager to track the locking state for a file. 94 * 95 * The ls_active list contains the set of active locks on the file. It 96 * is strictly ordered by the lock's lf_start value. Each active lock 97 * will have in-coming edges to any pending lock which it blocks. 98 * 99 * Lock requests which are blocked by some other active lock are 100 * listed in ls_pending with newer requests first in the list. Lock 101 * requests in this list will have out-going edges to each active lock 102 * that blocks then. They will also have out-going edges to each 103 * pending lock that is older in the queue - this helps to ensure 104 * fairness when several processes are contenting to lock the same 105 * record. 106 107 * The value of ls_threads is the number of threads currently using 108 * the state structure (typically either setting/clearing locks or 109 * sleeping waiting to do so). This is used to defer freeing the 110 * structure while some thread is still using it. 111 */ 112 struct lockf { 113 LIST_ENTRY(lockf) ls_link; /* (S) all active lockf states */ 114 struct sx ls_lock; 115 struct lockf_entry_list ls_active; /* (s) Active locks */ 116 struct lockf_entry_list ls_pending; /* (s) Pending locks */ 117 int ls_threads; /* (i) Thread count */ 118 }; 119 LIST_HEAD(lockf_list, lockf); 120 121 typedef int lf_iterator(struct vnode *, struct flock *, void *); 122 123 int lf_advlock(struct vop_advlock_args *, struct lockf **, u_quad_t); 124 int lf_advlockasync(struct vop_advlockasync_args *, struct lockf **, u_quad_t); 125 void lf_purgelocks(struct vnode *vp, struct lockf **statep); 126 int lf_iteratelocks_sysid(int sysid, lf_iterator *, void *); 127 int lf_iteratelocks_vnode(struct vnode *vp, lf_iterator *, void *); 128 int lf_countlocks(int sysid); 129 void lf_clearremotesys(int sysid); 130 131 #endif /* !_SYS_LOCKF_H_ */ 132