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