xref: /linux/fs/gfs2/glock.h (revision d6a5c562214f26e442c8ec3ff1e28e16675d1bcf)
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_NOPID		0x0200
95 #define GL_NOCACHE		0x0400
96 
97 /*
98  * lm_async_cb return flags
99  *
100  * LM_OUT_ST_MASK
101  * Masks the lower two bits of lock state in the returned value.
102  *
103  * LM_OUT_CANCELED
104  * The lock request was canceled.
105  *
106  */
107 
108 #define LM_OUT_ST_MASK		0x00000003
109 #define LM_OUT_CANCELED		0x00000008
110 #define LM_OUT_ERROR		0x00000004
111 
112 /*
113  * lm_recovery_done() messages
114  */
115 
116 #define LM_RD_GAVEUP		308
117 #define LM_RD_SUCCESS		309
118 
119 #define GLR_TRYFAILED		13
120 
121 #define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
122 #define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
123 #define GL_GLOCK_MIN_HOLD        (long)(10)
124 #define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
125 #define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
126 
127 struct lm_lockops {
128 	const char *lm_proto_name;
129 	int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
130 	void (*lm_first_done) (struct gfs2_sbd *sdp);
131 	void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
132 				    unsigned int result);
133 	void (*lm_unmount) (struct gfs2_sbd *sdp);
134 	void (*lm_withdraw) (struct gfs2_sbd *sdp);
135 	void (*lm_put_lock) (struct gfs2_glock *gl);
136 	int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
137 			unsigned int flags);
138 	void (*lm_cancel) (struct gfs2_glock *gl);
139 	const match_table_t *lm_tokens;
140 };
141 
142 struct gfs2_glock_aspace {
143 	struct gfs2_glock glock;
144 	struct address_space mapping;
145 };
146 
147 extern struct workqueue_struct *gfs2_delete_workqueue;
148 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
149 {
150 	struct gfs2_holder *gh;
151 	struct pid *pid;
152 
153 	/* Look in glock's list of holders for one with current task as owner */
154 	spin_lock(&gl->gl_lockref.lock);
155 	pid = task_pid(current);
156 	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
157 		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
158 			break;
159 		if (test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags))
160 			continue;
161 		if (gh->gh_owner_pid == pid)
162 			goto out;
163 	}
164 	gh = NULL;
165 out:
166 	spin_unlock(&gl->gl_lockref.lock);
167 
168 	return gh;
169 }
170 
171 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
172 {
173 	return gl->gl_state == LM_ST_EXCLUSIVE;
174 }
175 
176 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
177 {
178 	return gl->gl_state == LM_ST_DEFERRED;
179 }
180 
181 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
182 {
183 	return gl->gl_state == LM_ST_SHARED;
184 }
185 
186 static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
187 {
188 	if (gl->gl_ops->go_flags & GLOF_ASPACE) {
189 		struct gfs2_glock_aspace *gla =
190 			container_of(gl, struct gfs2_glock_aspace, glock);
191 		return &gla->mapping;
192 	}
193 	return NULL;
194 }
195 
196 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
197 			  const struct gfs2_glock_operations *glops,
198 			  int create, struct gfs2_glock **glp);
199 extern void gfs2_glock_hold(struct gfs2_glock *gl);
200 extern void gfs2_glock_put(struct gfs2_glock *gl);
201 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
202 
203 extern void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
204 			       u16 flags, struct gfs2_holder *gh,
205 			       unsigned long ip);
206 static inline void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
207 				    u16 flags, struct gfs2_holder *gh) {
208 	__gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
209 }
210 
211 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
212 			       struct gfs2_holder *gh);
213 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
214 extern int gfs2_glock_nq(struct gfs2_holder *gh);
215 extern int gfs2_glock_poll(struct gfs2_holder *gh);
216 extern int gfs2_instantiate(struct gfs2_holder *gh);
217 extern int gfs2_glock_holder_ready(struct gfs2_holder *gh);
218 extern int gfs2_glock_wait(struct gfs2_holder *gh);
219 extern int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs);
220 extern void gfs2_glock_dq(struct gfs2_holder *gh);
221 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
222 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
223 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
224 			     const struct gfs2_glock_operations *glops,
225 			     unsigned int state, u16 flags,
226 			     struct gfs2_holder *gh);
227 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
228 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
229 extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
230 			    bool fsid);
231 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {		\
232 			gfs2_dump_glock(NULL, gl, true);	\
233 			BUG(); } } while(0)
234 #define gfs2_glock_assert_warn(gl, x) do { if (unlikely(!(x))) {	\
235 			gfs2_dump_glock(NULL, gl, true);		\
236 			gfs2_assert_warn((gl)->gl_name.ln_sbd, (x)); } } \
237 	while (0)
238 #define gfs2_glock_assert_withdraw(gl, x) do { if (unlikely(!(x))) {	\
239 			gfs2_dump_glock(NULL, gl, true);		\
240 			gfs2_assert_withdraw((gl)->gl_name.ln_sbd, (x)); } } \
241 	while (0)
242 
243 extern __printf(2, 3)
244 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
245 
246 /**
247  * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
248  * @gl: the glock
249  * @state: the state we're requesting
250  * @flags: the modifier flags
251  * @gh: the holder structure
252  *
253  * Returns: 0, GLR_*, or errno
254  */
255 
256 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
257 				     unsigned int state, u16 flags,
258 				     struct gfs2_holder *gh)
259 {
260 	int error;
261 
262 	__gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
263 
264 	error = gfs2_glock_nq(gh);
265 	if (error)
266 		gfs2_holder_uninit(gh);
267 
268 	return error;
269 }
270 
271 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
272 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
273 extern bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay);
274 extern void gfs2_cancel_delete_work(struct gfs2_glock *gl);
275 extern bool gfs2_delete_work_queued(const struct gfs2_glock *gl);
276 extern void gfs2_flush_delete_work(struct gfs2_sbd *sdp);
277 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
278 extern void gfs2_gl_dq_holders(struct gfs2_sbd *sdp);
279 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
280 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
281 extern void gfs2_glock_free(struct gfs2_glock *gl);
282 
283 extern int __init gfs2_glock_init(void);
284 extern void gfs2_glock_exit(void);
285 
286 extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
287 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
288 extern void gfs2_register_debugfs(void);
289 extern void gfs2_unregister_debugfs(void);
290 
291 extern const struct lm_lockops gfs2_dlm_ops;
292 
293 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
294 {
295 	gh->gh_gl = NULL;
296 }
297 
298 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
299 {
300 	return gh->gh_gl;
301 }
302 
303 static inline bool gfs2_holder_queued(struct gfs2_holder *gh)
304 {
305 	return !list_empty(&gh->gh_list);
306 }
307 
308 /**
309  * glock_set_object - set the gl_object field of a glock
310  * @gl: the glock
311  * @object: the object
312  */
313 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
314 {
315 	spin_lock(&gl->gl_lockref.lock);
316 	if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
317 		gfs2_dump_glock(NULL, gl, true);
318 	gl->gl_object = object;
319 	spin_unlock(&gl->gl_lockref.lock);
320 }
321 
322 /**
323  * glock_clear_object - clear the gl_object field of a glock
324  * @gl: the glock
325  * @object: the object
326  *
327  * I'd love to similarly add this:
328  *	else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
329  *		gfs2_dump_glock(NULL, gl, true);
330  * Unfortunately, that's not possible because as soon as gfs2_delete_inode
331  * frees the block in the rgrp, another process can reassign it for an I_NEW
332  * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
333  * That means gfs2_delete_inode may subsequently try to call this function
334  * for a glock that's already pointing to a brand new inode. If we clear the
335  * new inode's gl_object, we'll introduce metadata corruption. Function
336  * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
337  * tries to clear gl_object, so it's more than just gfs2_delete_inode.
338  *
339  */
340 static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
341 {
342 	spin_lock(&gl->gl_lockref.lock);
343 	if (gl->gl_object == object)
344 		gl->gl_object = NULL;
345 	spin_unlock(&gl->gl_lockref.lock);
346 }
347 
348 static inline void gfs2_holder_allow_demote(struct gfs2_holder *gh)
349 {
350 	struct gfs2_glock *gl = gh->gh_gl;
351 
352 	spin_lock(&gl->gl_lockref.lock);
353 	set_bit(HIF_MAY_DEMOTE, &gh->gh_iflags);
354 	spin_unlock(&gl->gl_lockref.lock);
355 }
356 
357 static inline void gfs2_holder_disallow_demote(struct gfs2_holder *gh)
358 {
359 	struct gfs2_glock *gl = gh->gh_gl;
360 
361 	spin_lock(&gl->gl_lockref.lock);
362 	clear_bit(HIF_MAY_DEMOTE, &gh->gh_iflags);
363 	spin_unlock(&gl->gl_lockref.lock);
364 }
365 
366 extern void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation);
367 extern bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation);
368 
369 #endif /* __GLOCK_DOT_H__ */
370