xref: /openbmc/linux/fs/gfs2/glock.h (revision 53f9cd5c)
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 struct gfs2_glock_aspace {
142 	struct gfs2_glock glock;
143 	struct address_space mapping;
144 };
145 
146 extern struct workqueue_struct *gfs2_delete_workqueue;
147 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
148 {
149 	struct gfs2_holder *gh;
150 	struct pid *pid;
151 
152 	/* Look in glock's list of holders for one with current task as owner */
153 	spin_lock(&gl->gl_lockref.lock);
154 	pid = task_pid(current);
155 	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
156 		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
157 			break;
158 		if (test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags))
159 			continue;
160 		if (gh->gh_owner_pid == pid)
161 			goto out;
162 	}
163 	gh = NULL;
164 out:
165 	spin_unlock(&gl->gl_lockref.lock);
166 
167 	return gh;
168 }
169 
170 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
171 {
172 	return gl->gl_state == LM_ST_EXCLUSIVE;
173 }
174 
175 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
176 {
177 	return gl->gl_state == LM_ST_DEFERRED;
178 }
179 
180 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
181 {
182 	return gl->gl_state == LM_ST_SHARED;
183 }
184 
185 static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
186 {
187 	if (gl->gl_ops->go_flags & GLOF_ASPACE) {
188 		struct gfs2_glock_aspace *gla =
189 			container_of(gl, struct gfs2_glock_aspace, glock);
190 		return &gla->mapping;
191 	}
192 	return NULL;
193 }
194 
195 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
196 			  const struct gfs2_glock_operations *glops,
197 			  int create, struct gfs2_glock **glp);
198 extern void gfs2_glock_hold(struct gfs2_glock *gl);
199 extern void gfs2_glock_put(struct gfs2_glock *gl);
200 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
201 
202 extern void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
203 			       u16 flags, struct gfs2_holder *gh,
204 			       unsigned long ip);
205 static inline void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
206 				    u16 flags, struct gfs2_holder *gh) {
207 	__gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
208 }
209 
210 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
211 			       struct gfs2_holder *gh);
212 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
213 extern int gfs2_glock_nq(struct gfs2_holder *gh);
214 extern int gfs2_glock_poll(struct gfs2_holder *gh);
215 extern int gfs2_instantiate(struct gfs2_holder *gh);
216 extern int gfs2_glock_holder_ready(struct gfs2_holder *gh);
217 extern int gfs2_glock_wait(struct gfs2_holder *gh);
218 extern int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs);
219 extern void gfs2_glock_dq(struct gfs2_holder *gh);
220 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
221 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
222 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
223 			     const struct gfs2_glock_operations *glops,
224 			     unsigned int state, u16 flags,
225 			     struct gfs2_holder *gh);
226 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
227 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
228 extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
229 			    bool fsid);
230 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {		\
231 			gfs2_dump_glock(NULL, gl, true);	\
232 			BUG(); } } while(0)
233 #define gfs2_glock_assert_warn(gl, x) do { if (unlikely(!(x))) {	\
234 			gfs2_dump_glock(NULL, gl, true);		\
235 			gfs2_assert_warn((gl)->gl_name.ln_sbd, (x)); } } \
236 	while (0)
237 #define gfs2_glock_assert_withdraw(gl, x) do { if (unlikely(!(x))) {	\
238 			gfs2_dump_glock(NULL, gl, true);		\
239 			gfs2_assert_withdraw((gl)->gl_name.ln_sbd, (x)); } } \
240 	while (0)
241 
242 extern __printf(2, 3)
243 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
244 
245 /**
246  * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
247  * @gl: the glock
248  * @state: the state we're requesting
249  * @flags: the modifier flags
250  * @gh: the holder structure
251  *
252  * Returns: 0, GLR_*, or errno
253  */
254 
255 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
256 				     unsigned int state, u16 flags,
257 				     struct gfs2_holder *gh)
258 {
259 	int error;
260 
261 	__gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
262 
263 	error = gfs2_glock_nq(gh);
264 	if (error)
265 		gfs2_holder_uninit(gh);
266 
267 	return error;
268 }
269 
270 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
271 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
272 extern bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay);
273 extern void gfs2_cancel_delete_work(struct gfs2_glock *gl);
274 extern bool gfs2_delete_work_queued(const struct gfs2_glock *gl);
275 extern void gfs2_flush_delete_work(struct gfs2_sbd *sdp);
276 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
277 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
278 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
279 extern void gfs2_glock_free(struct gfs2_glock *gl);
280 
281 extern int __init gfs2_glock_init(void);
282 extern void gfs2_glock_exit(void);
283 
284 extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
285 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
286 extern void gfs2_register_debugfs(void);
287 extern void gfs2_unregister_debugfs(void);
288 
289 extern const struct lm_lockops gfs2_dlm_ops;
290 
291 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
292 {
293 	gh->gh_gl = NULL;
294 }
295 
296 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
297 {
298 	return gh->gh_gl;
299 }
300 
301 static inline bool gfs2_holder_queued(struct gfs2_holder *gh)
302 {
303 	return !list_empty(&gh->gh_list);
304 }
305 
306 /**
307  * glock_set_object - set the gl_object field of a glock
308  * @gl: the glock
309  * @object: the object
310  */
311 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
312 {
313 	spin_lock(&gl->gl_lockref.lock);
314 	if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
315 		gfs2_dump_glock(NULL, gl, true);
316 	gl->gl_object = object;
317 	spin_unlock(&gl->gl_lockref.lock);
318 }
319 
320 /**
321  * glock_clear_object - clear the gl_object field of a glock
322  * @gl: the glock
323  * @object: the object
324  *
325  * I'd love to similarly add this:
326  *	else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
327  *		gfs2_dump_glock(NULL, gl, true);
328  * Unfortunately, that's not possible because as soon as gfs2_delete_inode
329  * frees the block in the rgrp, another process can reassign it for an I_NEW
330  * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
331  * That means gfs2_delete_inode may subsequently try to call this function
332  * for a glock that's already pointing to a brand new inode. If we clear the
333  * new inode's gl_object, we'll introduce metadata corruption. Function
334  * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
335  * tries to clear gl_object, so it's more than just gfs2_delete_inode.
336  *
337  */
338 static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
339 {
340 	spin_lock(&gl->gl_lockref.lock);
341 	if (gl->gl_object == object)
342 		gl->gl_object = NULL;
343 	spin_unlock(&gl->gl_lockref.lock);
344 }
345 
346 static inline void gfs2_holder_allow_demote(struct gfs2_holder *gh)
347 {
348 	struct gfs2_glock *gl = gh->gh_gl;
349 
350 	spin_lock(&gl->gl_lockref.lock);
351 	set_bit(HIF_MAY_DEMOTE, &gh->gh_iflags);
352 	spin_unlock(&gl->gl_lockref.lock);
353 }
354 
355 static inline void gfs2_holder_disallow_demote(struct gfs2_holder *gh)
356 {
357 	struct gfs2_glock *gl = gh->gh_gl;
358 
359 	spin_lock(&gl->gl_lockref.lock);
360 	clear_bit(HIF_MAY_DEMOTE, &gh->gh_iflags);
361 	spin_unlock(&gl->gl_lockref.lock);
362 }
363 
364 extern void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation);
365 extern bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation);
366 
367 #endif /* __GLOCK_DOT_H__ */
368