xref: /openbmc/linux/fs/gfs2/glock.h (revision 62e7ca52)
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License version 2.
8  */
9 
10 #ifndef __GLOCK_DOT_H__
11 #define __GLOCK_DOT_H__
12 
13 #include <linux/sched.h>
14 #include <linux/parser.h>
15 #include "incore.h"
16 
17 /* Options for hostdata parser */
18 
19 enum {
20 	Opt_jid,
21 	Opt_id,
22 	Opt_first,
23 	Opt_nodir,
24 	Opt_err,
25 };
26 
27 /*
28  * lm_lockname types
29  */
30 
31 #define LM_TYPE_RESERVED	0x00
32 #define LM_TYPE_NONDISK		0x01
33 #define LM_TYPE_INODE		0x02
34 #define LM_TYPE_RGRP		0x03
35 #define LM_TYPE_META		0x04
36 #define LM_TYPE_IOPEN		0x05
37 #define LM_TYPE_FLOCK		0x06
38 #define LM_TYPE_PLOCK		0x07
39 #define LM_TYPE_QUOTA		0x08
40 #define LM_TYPE_JOURNAL		0x09
41 
42 /*
43  * lm_lock() states
44  *
45  * SHARED is compatible with SHARED, not with DEFERRED or EX.
46  * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
47  */
48 
49 #define LM_ST_UNLOCKED		0
50 #define LM_ST_EXCLUSIVE		1
51 #define LM_ST_DEFERRED		2
52 #define LM_ST_SHARED		3
53 
54 /*
55  * lm_lock() flags
56  *
57  * LM_FLAG_TRY
58  * Don't wait to acquire the lock if it can't be granted immediately.
59  *
60  * LM_FLAG_TRY_1CB
61  * Send one blocking callback if TRY is set and the lock is not granted.
62  *
63  * LM_FLAG_NOEXP
64  * GFS sets this flag on lock requests it makes while doing journal recovery.
65  * These special requests should not be blocked due to the recovery like
66  * ordinary locks would be.
67  *
68  * LM_FLAG_ANY
69  * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
70  * also be granted in SHARED.  The preferred state is whichever is compatible
71  * with other granted locks, or the specified state if no other locks exist.
72  *
73  * LM_FLAG_PRIORITY
74  * Override fairness considerations.  Suppose a lock is held in a shared state
75  * and there is a pending request for the deferred state.  A shared lock
76  * request with the priority flag would be allowed to bypass the deferred
77  * request and directly join the other shared lock.  A shared lock request
78  * without the priority flag might be forced to wait until the deferred
79  * requested had acquired and released the lock.
80  */
81 
82 #define LM_FLAG_TRY		0x00000001
83 #define LM_FLAG_TRY_1CB		0x00000002
84 #define LM_FLAG_NOEXP		0x00000004
85 #define LM_FLAG_ANY		0x00000008
86 #define LM_FLAG_PRIORITY	0x00000010
87 #define GL_ASYNC		0x00000040
88 #define GL_EXACT		0x00000080
89 #define GL_SKIP			0x00000100
90 #define GL_NOCACHE		0x00000400
91 
92 /*
93  * lm_async_cb return flags
94  *
95  * LM_OUT_ST_MASK
96  * Masks the lower two bits of lock state in the returned value.
97  *
98  * LM_OUT_CANCELED
99  * The lock request was canceled.
100  *
101  */
102 
103 #define LM_OUT_ST_MASK		0x00000003
104 #define LM_OUT_CANCELED		0x00000008
105 #define LM_OUT_ERROR		0x00000004
106 
107 /*
108  * lm_recovery_done() messages
109  */
110 
111 #define LM_RD_GAVEUP		308
112 #define LM_RD_SUCCESS		309
113 
114 #define GLR_TRYFAILED		13
115 
116 #define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
117 #define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
118 #define GL_GLOCK_MIN_HOLD        (long)(10)
119 #define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
120 #define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
121 
122 struct lm_lockops {
123 	const char *lm_proto_name;
124 	int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
125 	void (*lm_first_done) (struct gfs2_sbd *sdp);
126 	void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
127 				    unsigned int result);
128 	void (*lm_unmount) (struct gfs2_sbd *sdp);
129 	void (*lm_withdraw) (struct gfs2_sbd *sdp);
130 	void (*lm_put_lock) (struct gfs2_glock *gl);
131 	int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
132 			unsigned int flags);
133 	void (*lm_cancel) (struct gfs2_glock *gl);
134 	const match_table_t *lm_tokens;
135 };
136 
137 extern struct workqueue_struct *gfs2_delete_workqueue;
138 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
139 {
140 	struct gfs2_holder *gh;
141 	struct pid *pid;
142 
143 	/* Look in glock's list of holders for one with current task as owner */
144 	spin_lock(&gl->gl_spin);
145 	pid = task_pid(current);
146 	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
147 		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
148 			break;
149 		if (gh->gh_owner_pid == pid)
150 			goto out;
151 	}
152 	gh = NULL;
153 out:
154 	spin_unlock(&gl->gl_spin);
155 
156 	return gh;
157 }
158 
159 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
160 {
161 	return gl->gl_state == LM_ST_EXCLUSIVE;
162 }
163 
164 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
165 {
166 	return gl->gl_state == LM_ST_DEFERRED;
167 }
168 
169 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
170 {
171 	return gl->gl_state == LM_ST_SHARED;
172 }
173 
174 static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
175 {
176 	if (gl->gl_ops->go_flags & GLOF_ASPACE)
177 		return (struct address_space *)(gl + 1);
178 	return NULL;
179 }
180 
181 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
182 			  const struct gfs2_glock_operations *glops,
183 			  int create, struct gfs2_glock **glp);
184 extern void gfs2_glock_put(struct gfs2_glock *gl);
185 extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
186 			     unsigned flags, struct gfs2_holder *gh);
187 extern void gfs2_holder_reinit(unsigned int state, unsigned flags,
188 			       struct gfs2_holder *gh);
189 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
190 extern int gfs2_glock_nq(struct gfs2_holder *gh);
191 extern int gfs2_glock_poll(struct gfs2_holder *gh);
192 extern int gfs2_glock_wait(struct gfs2_holder *gh);
193 extern void gfs2_glock_dq(struct gfs2_holder *gh);
194 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
195 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
196 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
197 			     const struct gfs2_glock_operations *glops,
198 			     unsigned int state, int flags,
199 			     struct gfs2_holder *gh);
200 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
201 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
202 extern void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
203 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { gfs2_dump_glock(NULL, gl); BUG(); } } while(0)
204 extern __printf(2, 3)
205 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
206 
207 /**
208  * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
209  * @gl: the glock
210  * @state: the state we're requesting
211  * @flags: the modifier flags
212  * @gh: the holder structure
213  *
214  * Returns: 0, GLR_*, or errno
215  */
216 
217 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
218 				     unsigned int state, int flags,
219 				     struct gfs2_holder *gh)
220 {
221 	int error;
222 
223 	gfs2_holder_init(gl, state, flags, gh);
224 
225 	error = gfs2_glock_nq(gh);
226 	if (error)
227 		gfs2_holder_uninit(gh);
228 
229 	return error;
230 }
231 
232 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
233 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
234 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
235 extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
236 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
237 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
238 extern void gfs2_glock_free(struct gfs2_glock *gl);
239 
240 extern int __init gfs2_glock_init(void);
241 extern void gfs2_glock_exit(void);
242 
243 extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
244 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
245 extern int gfs2_register_debugfs(void);
246 extern void gfs2_unregister_debugfs(void);
247 
248 extern const struct lm_lockops gfs2_dlm_ops;
249 
250 #endif /* __GLOCK_DOT_H__ */
251