xref: /openbmc/linux/fs/gfs2/glock.h (revision c4f7ac64)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
4  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
5  */
6 
7 #ifndef __GLOCK_DOT_H__
8 #define __GLOCK_DOT_H__
9 
10 #include <linux/sched.h>
11 #include <linux/parser.h>
12 #include "incore.h"
13 #include "util.h"
14 
15 /* Options for hostdata parser */
16 
17 enum {
18 	Opt_jid,
19 	Opt_id,
20 	Opt_first,
21 	Opt_nodir,
22 	Opt_err,
23 };
24 
25 /*
26  * lm_lockname types
27  */
28 
29 #define LM_TYPE_RESERVED	0x00
30 #define LM_TYPE_NONDISK		0x01
31 #define LM_TYPE_INODE		0x02
32 #define LM_TYPE_RGRP		0x03
33 #define LM_TYPE_META		0x04
34 #define LM_TYPE_IOPEN		0x05
35 #define LM_TYPE_FLOCK		0x06
36 #define LM_TYPE_PLOCK		0x07
37 #define LM_TYPE_QUOTA		0x08
38 #define LM_TYPE_JOURNAL		0x09
39 
40 /*
41  * lm_lock() states
42  *
43  * SHARED is compatible with SHARED, not with DEFERRED or EX.
44  * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
45  */
46 
47 #define LM_ST_UNLOCKED		0
48 #define LM_ST_EXCLUSIVE		1
49 #define LM_ST_DEFERRED		2
50 #define LM_ST_SHARED		3
51 
52 /*
53  * lm_lock() flags
54  *
55  * LM_FLAG_TRY
56  * Don't wait to acquire the lock if it can't be granted immediately.
57  *
58  * LM_FLAG_TRY_1CB
59  * Send one blocking callback if TRY is set and the lock is not granted.
60  *
61  * LM_FLAG_NOEXP
62  * GFS sets this flag on lock requests it makes while doing journal recovery.
63  * These special requests should not be blocked due to the recovery like
64  * ordinary locks would be.
65  *
66  * LM_FLAG_ANY
67  * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
68  * also be granted in SHARED.  The preferred state is whichever is compatible
69  * with other granted locks, or the specified state if no other locks exist.
70  *
71  * LM_FLAG_PRIORITY
72  * Override fairness considerations.  Suppose a lock is held in a shared state
73  * and there is a pending request for the deferred state.  A shared lock
74  * request with the priority flag would be allowed to bypass the deferred
75  * request and directly join the other shared lock.  A shared lock request
76  * without the priority flag might be forced to wait until the deferred
77  * requested had acquired and released the lock.
78  *
79  * LM_FLAG_NODE_SCOPE
80  * This holder agrees to share the lock within this node. In other words,
81  * the glock is held in EX mode according to DLM, but local holders on the
82  * same node can share it.
83  */
84 
85 #define LM_FLAG_TRY		0x0001
86 #define LM_FLAG_TRY_1CB		0x0002
87 #define LM_FLAG_NOEXP		0x0004
88 #define LM_FLAG_ANY		0x0008
89 #define LM_FLAG_PRIORITY	0x0010
90 #define LM_FLAG_NODE_SCOPE	0x0020
91 #define GL_ASYNC		0x0040
92 #define GL_EXACT		0x0080
93 #define GL_SKIP			0x0100
94 #define GL_NOCACHE		0x0400
95 
96 /*
97  * lm_async_cb return flags
98  *
99  * LM_OUT_ST_MASK
100  * Masks the lower two bits of lock state in the returned value.
101  *
102  * LM_OUT_CANCELED
103  * The lock request was canceled.
104  *
105  */
106 
107 #define LM_OUT_ST_MASK		0x00000003
108 #define LM_OUT_CANCELED		0x00000008
109 #define LM_OUT_ERROR		0x00000004
110 
111 /*
112  * lm_recovery_done() messages
113  */
114 
115 #define LM_RD_GAVEUP		308
116 #define LM_RD_SUCCESS		309
117 
118 #define GLR_TRYFAILED		13
119 
120 #define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
121 #define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
122 #define GL_GLOCK_MIN_HOLD        (long)(10)
123 #define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
124 #define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
125 
126 struct lm_lockops {
127 	const char *lm_proto_name;
128 	int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
129 	void (*lm_first_done) (struct gfs2_sbd *sdp);
130 	void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
131 				    unsigned int result);
132 	void (*lm_unmount) (struct gfs2_sbd *sdp);
133 	void (*lm_withdraw) (struct gfs2_sbd *sdp);
134 	void (*lm_put_lock) (struct gfs2_glock *gl);
135 	int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
136 			unsigned int flags);
137 	void (*lm_cancel) (struct gfs2_glock *gl);
138 	const match_table_t *lm_tokens;
139 };
140 
141 extern struct workqueue_struct *gfs2_delete_workqueue;
142 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
143 {
144 	struct gfs2_holder *gh;
145 	struct pid *pid;
146 
147 	/* Look in glock's list of holders for one with current task as owner */
148 	spin_lock(&gl->gl_lockref.lock);
149 	pid = task_pid(current);
150 	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
151 		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
152 			break;
153 		if (gh->gh_owner_pid == pid)
154 			goto out;
155 	}
156 	gh = NULL;
157 out:
158 	spin_unlock(&gl->gl_lockref.lock);
159 
160 	return gh;
161 }
162 
163 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
164 {
165 	return gl->gl_state == LM_ST_EXCLUSIVE;
166 }
167 
168 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
169 {
170 	return gl->gl_state == LM_ST_DEFERRED;
171 }
172 
173 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
174 {
175 	return gl->gl_state == LM_ST_SHARED;
176 }
177 
178 static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
179 {
180 	if (gl->gl_ops->go_flags & GLOF_ASPACE)
181 		return (struct address_space *)(gl + 1);
182 	return NULL;
183 }
184 
185 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
186 			  const struct gfs2_glock_operations *glops,
187 			  int create, struct gfs2_glock **glp);
188 extern void gfs2_glock_hold(struct gfs2_glock *gl);
189 extern void gfs2_glock_put(struct gfs2_glock *gl);
190 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
191 extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
192 			     u16 flags, struct gfs2_holder *gh);
193 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
194 			       struct gfs2_holder *gh);
195 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
196 extern int gfs2_glock_nq(struct gfs2_holder *gh);
197 extern int gfs2_glock_poll(struct gfs2_holder *gh);
198 extern int gfs2_glock_wait(struct gfs2_holder *gh);
199 extern int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs);
200 extern void gfs2_glock_dq(struct gfs2_holder *gh);
201 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
202 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
203 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
204 			     const struct gfs2_glock_operations *glops,
205 			     unsigned int state, u16 flags,
206 			     struct gfs2_holder *gh);
207 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
208 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
209 extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
210 			    bool fsid);
211 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {		\
212 			gfs2_dump_glock(NULL, gl, true);	\
213 			BUG(); } } while(0)
214 #define gfs2_glock_assert_warn(gl, x) do { if (unlikely(!(x))) {	\
215 			gfs2_dump_glock(NULL, gl, true);		\
216 			gfs2_assert_warn((gl)->gl_name.ln_sbd, (x)); } } \
217 	while (0)
218 #define gfs2_glock_assert_withdraw(gl, x) do { if (unlikely(!(x))) {	\
219 			gfs2_dump_glock(NULL, gl, true);		\
220 			gfs2_assert_withdraw((gl)->gl_name.ln_sbd, (x)); } } \
221 	while (0)
222 
223 extern __printf(2, 3)
224 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
225 
226 /**
227  * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
228  * @gl: the glock
229  * @state: the state we're requesting
230  * @flags: the modifier flags
231  * @gh: the holder structure
232  *
233  * Returns: 0, GLR_*, or errno
234  */
235 
236 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
237 				     unsigned int state, u16 flags,
238 				     struct gfs2_holder *gh)
239 {
240 	int error;
241 
242 	gfs2_holder_init(gl, state, flags, gh);
243 
244 	error = gfs2_glock_nq(gh);
245 	if (error)
246 		gfs2_holder_uninit(gh);
247 
248 	return error;
249 }
250 
251 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
252 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
253 extern bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay);
254 extern void gfs2_cancel_delete_work(struct gfs2_glock *gl);
255 extern bool gfs2_delete_work_queued(const struct gfs2_glock *gl);
256 extern void gfs2_flush_delete_work(struct gfs2_sbd *sdp);
257 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
258 extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
259 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
260 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
261 extern void gfs2_glock_free(struct gfs2_glock *gl);
262 
263 extern int __init gfs2_glock_init(void);
264 extern void gfs2_glock_exit(void);
265 
266 extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
267 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
268 extern void gfs2_register_debugfs(void);
269 extern void gfs2_unregister_debugfs(void);
270 
271 extern const struct lm_lockops gfs2_dlm_ops;
272 
273 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
274 {
275 	gh->gh_gl = NULL;
276 }
277 
278 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
279 {
280 	return gh->gh_gl;
281 }
282 
283 static inline bool gfs2_holder_queued(struct gfs2_holder *gh)
284 {
285 	return !list_empty(&gh->gh_list);
286 }
287 
288 /**
289  * glock_set_object - set the gl_object field of a glock
290  * @gl: the glock
291  * @object: the object
292  */
293 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
294 {
295 	spin_lock(&gl->gl_lockref.lock);
296 	if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
297 		gfs2_dump_glock(NULL, gl, true);
298 	gl->gl_object = object;
299 	spin_unlock(&gl->gl_lockref.lock);
300 }
301 
302 /**
303  * glock_clear_object - clear the gl_object field of a glock
304  * @gl: the glock
305  * @object: the object
306  *
307  * I'd love to similarly add this:
308  *	else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
309  *		gfs2_dump_glock(NULL, gl, true);
310  * Unfortunately, that's not possible because as soon as gfs2_delete_inode
311  * frees the block in the rgrp, another process can reassign it for an I_NEW
312  * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
313  * That means gfs2_delete_inode may subsequently try to call this function
314  * for a glock that's already pointing to a brand new inode. If we clear the
315  * new inode's gl_object, we'll introduce metadata corruption. Function
316  * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
317  * tries to clear gl_object, so it's more than just gfs2_delete_inode.
318  *
319  */
320 static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
321 {
322 	spin_lock(&gl->gl_lockref.lock);
323 	if (gl->gl_object == object)
324 		gl->gl_object = NULL;
325 	spin_unlock(&gl->gl_lockref.lock);
326 }
327 
328 extern void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation);
329 extern bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation);
330 
331 #endif /* __GLOCK_DOT_H__ */
332