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 #include "util.h"
17
18 /* Options for hostdata parser */
19
20 enum {
21 Opt_jid,
22 Opt_id,
23 Opt_first,
24 Opt_nodir,
25 Opt_err,
26 };
27
28 /*
29 * lm_lockname types
30 */
31
32 #define LM_TYPE_RESERVED 0x00
33 #define LM_TYPE_NONDISK 0x01
34 #define LM_TYPE_INODE 0x02
35 #define LM_TYPE_RGRP 0x03
36 #define LM_TYPE_META 0x04
37 #define LM_TYPE_IOPEN 0x05
38 #define LM_TYPE_FLOCK 0x06
39 #define LM_TYPE_PLOCK 0x07
40 #define LM_TYPE_QUOTA 0x08
41 #define LM_TYPE_JOURNAL 0x09
42
43 /*
44 * lm_lock() states
45 *
46 * SHARED is compatible with SHARED, not with DEFERRED or EX.
47 * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
48 */
49
50 #define LM_ST_UNLOCKED 0
51 #define LM_ST_EXCLUSIVE 1
52 #define LM_ST_DEFERRED 2
53 #define LM_ST_SHARED 3
54
55 /*
56 * lm_lock() flags
57 *
58 * LM_FLAG_TRY
59 * Don't wait to acquire the lock if it can't be granted immediately.
60 *
61 * LM_FLAG_TRY_1CB
62 * Send one blocking callback if TRY is set and the lock is not granted.
63 *
64 * LM_FLAG_NOEXP
65 * GFS sets this flag on lock requests it makes while doing journal recovery.
66 * These special requests should not be blocked due to the recovery like
67 * ordinary locks would be.
68 *
69 * LM_FLAG_ANY
70 * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
71 * also be granted in SHARED. The preferred state is whichever is compatible
72 * with other granted locks, or the specified state if no other locks exist.
73 *
74 * LM_FLAG_PRIORITY
75 * Override fairness considerations. Suppose a lock is held in a shared state
76 * and there is a pending request for the deferred state. A shared lock
77 * request with the priority flag would be allowed to bypass the deferred
78 * request and directly join the other shared lock. A shared lock request
79 * without the priority flag might be forced to wait until the deferred
80 * requested had acquired and released the lock.
81 */
82
83 #define LM_FLAG_TRY 0x0001
84 #define LM_FLAG_TRY_1CB 0x0002
85 #define LM_FLAG_NOEXP 0x0004
86 #define LM_FLAG_ANY 0x0008
87 #define LM_FLAG_PRIORITY 0x0010
88 #define GL_ASYNC 0x0040
89 #define GL_EXACT 0x0080
90 #define GL_SKIP 0x0100
91 #define GL_NOCACHE 0x0400
92
93 /*
94 * lm_async_cb return flags
95 *
96 * LM_OUT_ST_MASK
97 * Masks the lower two bits of lock state in the returned value.
98 *
99 * LM_OUT_CANCELED
100 * The lock request was canceled.
101 *
102 */
103
104 #define LM_OUT_ST_MASK 0x00000003
105 #define LM_OUT_CANCELED 0x00000008
106 #define LM_OUT_ERROR 0x00000004
107
108 /*
109 * lm_recovery_done() messages
110 */
111
112 #define LM_RD_GAVEUP 308
113 #define LM_RD_SUCCESS 309
114
115 #define GLR_TRYFAILED 13
116
117 #define GL_GLOCK_MAX_HOLD (long)(HZ / 5)
118 #define GL_GLOCK_DFT_HOLD (long)(HZ / 5)
119 #define GL_GLOCK_MIN_HOLD (long)(10)
120 #define GL_GLOCK_HOLD_INCR (long)(HZ / 20)
121 #define GL_GLOCK_HOLD_DECR (long)(HZ / 40)
122
123 struct lm_lockops {
124 const char *lm_proto_name;
125 int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
126 void (*lm_first_done) (struct gfs2_sbd *sdp);
127 void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
128 unsigned int result);
129 void (*lm_unmount) (struct gfs2_sbd *sdp);
130 void (*lm_withdraw) (struct gfs2_sbd *sdp);
131 void (*lm_put_lock) (struct gfs2_glock *gl);
132 int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
133 unsigned int flags);
134 void (*lm_cancel) (struct gfs2_glock *gl);
135 const match_table_t *lm_tokens;
136 };
137
138 extern struct workqueue_struct *gfs2_delete_workqueue;
gfs2_glock_is_locked_by_me(struct gfs2_glock * gl)139 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
140 {
141 struct gfs2_holder *gh;
142 struct pid *pid;
143
144 /* Look in glock's list of holders for one with current task as owner */
145 spin_lock(&gl->gl_lockref.lock);
146 pid = task_pid(current);
147 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
148 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
149 break;
150 if (gh->gh_owner_pid == pid)
151 goto out;
152 }
153 gh = NULL;
154 out:
155 spin_unlock(&gl->gl_lockref.lock);
156
157 return gh;
158 }
159
gfs2_glock_is_held_excl(struct gfs2_glock * gl)160 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
161 {
162 return gl->gl_state == LM_ST_EXCLUSIVE;
163 }
164
gfs2_glock_is_held_dfrd(struct gfs2_glock * gl)165 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
166 {
167 return gl->gl_state == LM_ST_DEFERRED;
168 }
169
gfs2_glock_is_held_shrd(struct gfs2_glock * gl)170 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
171 {
172 return gl->gl_state == LM_ST_SHARED;
173 }
174
gfs2_glock2aspace(struct gfs2_glock * gl)175 static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
176 {
177 if (gl->gl_ops->go_flags & GLOF_ASPACE)
178 return (struct address_space *)(gl + 1);
179 return NULL;
180 }
181
182 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
183 const struct gfs2_glock_operations *glops,
184 int create, struct gfs2_glock **glp);
185 extern void gfs2_glock_hold(struct gfs2_glock *gl);
186 extern void gfs2_glock_put(struct gfs2_glock *gl);
187 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
188 extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
189 u16 flags, struct gfs2_holder *gh);
190 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
191 struct gfs2_holder *gh);
192 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
193 extern int gfs2_glock_nq(struct gfs2_holder *gh);
194 extern int gfs2_glock_poll(struct gfs2_holder *gh);
195 extern int gfs2_glock_wait(struct gfs2_holder *gh);
196 extern void gfs2_glock_dq(struct gfs2_holder *gh);
197 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
198 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
199 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
200 const struct gfs2_glock_operations *glops,
201 unsigned int state, u16 flags,
202 struct gfs2_holder *gh);
203 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
204 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
205 extern void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
206 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { gfs2_dump_glock(NULL, gl); BUG(); } } while(0)
207 extern __printf(2, 3)
208 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
209
210 /**
211 * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
212 * @gl: the glock
213 * @state: the state we're requesting
214 * @flags: the modifier flags
215 * @gh: the holder structure
216 *
217 * Returns: 0, GLR_*, or errno
218 */
219
gfs2_glock_nq_init(struct gfs2_glock * gl,unsigned int state,u16 flags,struct gfs2_holder * gh)220 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
221 unsigned int state, u16 flags,
222 struct gfs2_holder *gh)
223 {
224 int error;
225
226 gfs2_holder_init(gl, state, flags, gh);
227
228 error = gfs2_glock_nq(gh);
229 if (error)
230 gfs2_holder_uninit(gh);
231
232 return error;
233 }
234
235 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
236 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
237 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
238 extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
239 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
240 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
241 extern void gfs2_glock_free(struct gfs2_glock *gl);
242
243 extern int __init gfs2_glock_init(void);
244 extern void gfs2_glock_exit(void);
245
246 extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
247 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
248 extern int gfs2_register_debugfs(void);
249 extern void gfs2_unregister_debugfs(void);
250
251 extern const struct lm_lockops gfs2_dlm_ops;
252
gfs2_holder_mark_uninitialized(struct gfs2_holder * gh)253 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
254 {
255 gh->gh_gl = NULL;
256 }
257
gfs2_holder_initialized(struct gfs2_holder * gh)258 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
259 {
260 return gh->gh_gl;
261 }
262
263 /**
264 * glock_set_object - set the gl_object field of a glock
265 * @gl: the glock
266 * @object: the object
267 */
glock_set_object(struct gfs2_glock * gl,void * object)268 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
269 {
270 spin_lock(&gl->gl_lockref.lock);
271 if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
272 gfs2_dump_glock(NULL, gl);
273 gl->gl_object = object;
274 spin_unlock(&gl->gl_lockref.lock);
275 }
276
277 /**
278 * glock_clear_object - clear the gl_object field of a glock
279 * @gl: the glock
280 * @object: the object
281 *
282 * I'd love to similarly add this:
283 * else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
284 * gfs2_dump_glock(NULL, gl);
285 * Unfortunately, that's not possible because as soon as gfs2_delete_inode
286 * frees the block in the rgrp, another process can reassign it for an I_NEW
287 * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
288 * That means gfs2_delete_inode may subsequently try to call this function
289 * for a glock that's already pointing to a brand new inode. If we clear the
290 * new inode's gl_object, we'll introduce metadata corruption. Function
291 * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
292 * tries to clear gl_object, so it's more than just gfs2_delete_inode.
293 *
294 */
glock_clear_object(struct gfs2_glock * gl,void * object)295 static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
296 {
297 spin_lock(&gl->gl_lockref.lock);
298 if (gl->gl_object == object)
299 gl->gl_object = NULL;
300 spin_unlock(&gl->gl_lockref.lock);
301 }
302
303 #endif /* __GLOCK_DOT_H__ */
304