xref: /illumos-gate/usr/src/uts/common/sys/flock.h (revision 88f8b78a88cbdc6d8c1af5c3e54bc49d25095c98)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23 /*	  All Rights Reserved  	*/
24 
25 
26 /*
27  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
28  * Use is subject to license terms.
29  */
30 
31 #ifndef _SYS_FLOCK_H
32 #define	_SYS_FLOCK_H
33 
34 #pragma ident	"%Z%%M%	%I%	%E% SMI"
35 
36 #include <sys/types.h>
37 #include <sys/fcntl.h>
38 #include <sys/vnode.h>
39 #include <sys/t_lock.h>		/* for <sys/callb.h> */
40 #include <sys/callb.h>
41 #include <sys/param.h>
42 #include <sys/zone.h>
43 
44 #ifdef	__cplusplus
45 extern "C" {
46 #endif
47 
48 /*
49  * Private declarations and instrumentation for local locking.
50  */
51 
52 /*
53  * The flag passed to fs_frlock() may be ORed together with either
54  * `F_REMOTELOCK' or `F_PXFSLOCK'.  Since this flag is initialized using the
55  * `f_flag' field in the `file' structure, and that field is an unsigned short,
56  * we do not use the first 2 bytes.
57  */
58 #define	F_REMOTELOCK	(0x01 << 16) /* Set if NLM lock */
59 #define	F_PXFSLOCK	(0x02 << 16) /* Clustering: set if PXFS lock */
60 
61 /*
62  * The command passed to reclock() is made by ORing together one or more of
63  * the following values.
64  */
65 
66 #define	INOFLCK		0x01	/* Vnode is locked when reclock() is called. */
67 #define	SETFLCK		0x02	/* Set a file lock. */
68 #define	SLPFLCK		0x04	/* Wait if blocked. */
69 #define	RCMDLCK		0x08	/* F_REMOTELOCK specified */
70 #define	PCMDLCK		0x10	/* Clustering: F_PXFSLOCK specified */
71 #define	NBMLCK		0x20	/* non-blocking mandatory locking */
72 
73 /*
74  * Special pid value that can be passed to cleanlocks().  It means that
75  * cleanlocks() should flush all locks for the given sysid, not just the
76  * locks owned by a specific process.
77  */
78 
79 #define	IGN_PID		(-1)
80 
81 /* file locking structure (connected to vnode) */
82 
83 #define	l_end		l_len
84 
85 /*
86  * The lock manager is allowed to use unsigned offsets and lengths, though
87  * regular Unix processes are still required to use signed offsets and
88  * lengths.
89  */
90 typedef ulong_t u_off_t;
91 
92 #define	MAX_U_OFF_T	((u_off_t)~0)
93 #define	MAX_U_OFFSET_T	((u_offset_t)~0)
94 
95 /*
96  * define MAXEND as the largest positive value the signed offset_t will hold.
97  */
98 #define	MAXEND		MAXOFFSET_T
99 
100 /*
101  * Definitions for accessing the l_pad area of struct flock.  The
102  * descriminant of the pad_info_t union is the fcntl command used in
103  * conjunction with the flock struct.
104  */
105 
106 typedef union {
107 	int	pi_pad[4];		/* (original pad area) */
108 	int	pi_has_rmt;		/* F_HASREMOTELOCKS */
109 } pad_info_t;
110 
111 #define	l_has_rmt(flockp)	(((pad_info_t *)((flockp)->l_pad))->pi_has_rmt)
112 
113 /*
114  * Optional callbacks for blocking lock requests.  Each function is called
115  * twice.
116  * The first call is after the request is put in the "sleeping" list, but
117  *   before waiting.  At most one callback may return a callb_cpr_t object;
118  *   the others must return NULL.  If a callb_cpr_t is returned, the thread
119  *   will be marked as safe to suspend while waiting for the lock.
120  * The second call is after the request wakes up.  Note that the request
121  *   might not have been granted at the second call (e.g., the request was
122  *   signalled).
123  * New callbacks should be added to the head of the list.  For the first
124  * call the list is walked in order.  For the second call the list is
125  * walked backwards (in case the callbacks need to reacquire locks).
126  */
127 
128 typedef enum {FLK_BEFORE_SLEEP, FLK_AFTER_SLEEP} flk_cb_when_t;
129 
130 struct flk_callback {
131 	struct flk_callback *cb_next;	/* circular linked list */
132 	struct flk_callback *cb_prev;
133 	callb_cpr_t	*(*cb_callback)(flk_cb_when_t, void *);	/* fcn ptr */
134 	void		*cb_data;	/* ptr to callback data */
135 };
136 
137 typedef struct flk_callback flk_callback_t;
138 
139 /*
140  * This structure members are not used any more inside the kernel.
141  * The structure is used for casting some pointer assignments only.
142  */
143 
144 typedef struct filock {
145 	kcondvar_t cv;
146 	struct	flock set;	/* contains type, start, and end */
147 	struct	{
148 		int granted_flag;	/* granted flag */
149 		struct filock *blk;	/* for sleeping locks only */
150 		struct attacher *blocking_list;
151 		struct attacher *my_attacher;
152 	}	stat;
153 	struct	filock *prev;
154 	struct	filock *next;
155 } filock_t;
156 
157 #define	FLP_DELAYED_FREE	-1	/* special value for granted_flag */
158 
159 /* structure that contains list of locks to be granted */
160 
161 #define	MAX_GRANT_LOCKS		52
162 
163 typedef struct grant_lock {
164 	struct filock *grant_lock_list[MAX_GRANT_LOCKS];
165 	struct grant_lock *next;
166 } grant_lock_t;
167 
168 /*
169  * Provide a way to cleanly enable and disable Network Lock Manager locking
170  * requests (i.e., requests from remote clients):
171  *    FLK_NLM_SHUTTING_DOWN: Forces all blocked NLM requests to bail out
172  *	and return ENOLCK.
173  *    FLK_NLM_DOWN: Clears all granted NLM server locks.  Both status
174  *	codes cause new NLM lock requests to fail immediately with ENOLCK.
175  *    FLK_NLM_UP: Changes the state of all locks to UP, after a server has
176  *	shutdown and is restarting on the same node.
177  */
178 
179 /*
180  * Enumerated type of the four possible states an NLM server can be in.
181  */
182 typedef enum {
183 	FLK_NLM_UP,
184 	FLK_NLM_SHUTTING_DOWN,
185 	FLK_NLM_DOWN,
186 	FLK_NLM_UNKNOWN
187 } flk_nlm_status_t;
188 
189 /*
190  * Provide a way to cleanly enable and disable lock manager locking
191  * requests (i.e., requests from remote clients).  FLK_WAKEUP_SLEEPERS
192  * forces all blocked lock manager requests to bail out and return ENOLCK.
193  * FLK_LOCKMGR_DOWN clears all granted lock manager locks.  Both status
194  * codes cause new lock manager requests to fail immediately with ENOLCK.
195  */
196 
197 typedef enum {
198     FLK_LOCKMGR_UP,
199     FLK_WAKEUP_SLEEPERS,
200     FLK_LOCKMGR_DOWN
201 } flk_lockmgr_status_t;
202 
203 #if defined(_KERNEL)
204 
205 /*
206  * The following structure is used to hold a list of locks returned
207  * by the F_ACTIVELIST or F_SLEEPINGLIST commands to fs_frlock.
208  *
209  * N.B. The lists returned by these commands are dynamically
210  * allocated and must be freed by the caller.  The vnodes returned
211  * in the lists are held and must be released when the caller is done.
212  */
213 
214 typedef struct locklist {
215 	struct vnode *ll_vp;
216 	struct flock64 ll_flock;
217 	struct locklist *ll_next;
218 } locklist_t;
219 
220 #define	FLK_QUERY_ACTIVE	0x1
221 #define	FLK_QUERY_SLEEPING	0x2
222 
223 int	reclock(struct vnode *, struct flock64 *, int, int, u_offset_t,
224 		flk_callback_t *);
225 int	chklock(struct vnode *, int, u_offset_t, ssize_t, int,
226 		caller_context_t *);
227 int	convoff(struct vnode *, struct flock64 *, int, offset_t);
228 void	cleanlocks(struct vnode *, pid_t, int);
229 locklist_t *flk_get_sleeping_locks(int sysid, pid_t pid);
230 locklist_t *flk_get_active_locks(int sysid, pid_t pid);
231 locklist_t *flk_active_locks_for_vp(const struct vnode *vp);
232 locklist_t *flk_active_nbmand_locks_for_vp(const struct vnode *vp);
233 locklist_t *flk_active_nbmand_locks(pid_t pid);
234 void	flk_free_locklist(locklist_t *);
235 int	flk_convert_lock_data(struct vnode *, struct flock64 *,
236 		u_offset_t *, u_offset_t *, offset_t);
237 int	flk_check_lock_data(u_offset_t, u_offset_t, offset_t);
238 int	flk_has_remote_locks(struct vnode *vp);
239 void	flk_set_lockmgr_status(flk_lockmgr_status_t status);
240 int	flk_sysid_has_locks(int sysid, int chklck);
241 void	flk_init_callback(flk_callback_t *,
242 		callb_cpr_t *(*)(flk_cb_when_t, void *), void *);
243 void	flk_add_callback(flk_callback_t *,
244 		callb_cpr_t *(*)(flk_cb_when_t, void *), void *,
245 		flk_callback_t *);
246 callb_cpr_t *flk_invoke_callbacks(flk_callback_t *, flk_cb_when_t);
247 
248 /* Zones hooks */
249 extern	zone_key_t flock_zone_key;
250 
251 void	*flk_zone_init(zoneid_t);
252 void	flk_zone_fini(zoneid_t, void *);
253 
254 /* Clustering hooks */
255 void	cl_flk_set_nlm_status(int nlmid, flk_nlm_status_t nlm_state);
256 void	cl_flk_remove_locks_by_sysid(int sysid);
257 int	cl_flk_has_remote_locks_for_nlmid(struct vnode *vp, int nlmid);
258 void	cl_flk_change_nlm_state_to_unknown(int nlmid);
259 void	cl_flk_delete_pxfs_locks(struct vfs *vfsp, int pxfsid);
260 #endif /* _KERNEL */
261 
262 #ifdef	__cplusplus
263 }
264 #endif
265 
266 #endif	/* _SYS_FLOCK_H */
267