2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * Scooter Morris at Genentech Inc.
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11 * modification, are permitted provided that the following conditions
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34 * @(#)lockf.h 8.1 (Berkeley) 6/11/93
41 #include <sys/queue.h>
42 #include <sys/_lock.h>
46 struct vop_advlock_args;
47 struct vop_advlockasync_args;
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.
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
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
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 */
71 LIST_HEAD(lockf_edge_list, lockf_edge);
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 */
87 LIST_HEAD(lockf_entry_list, lockf_entry);
90 * Extra lf_flags bits used by the implementation
92 #define F_INTR 0x8000 /* lock was interrupted by lf_purgelocks */
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.
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.
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
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.
117 LIST_ENTRY(lockf) ls_link; /* (S) all active lockf states */
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 */
123 LIST_HEAD(lockf_list, lockf);
125 typedef int lf_iterator(struct vnode *, struct flock *, void *);
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);
135 #endif /* !_SYS_LOCKF_H_ */