1/******************************************************************************
2*******************************************************************************
3**
4**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5**  Copyright (C) 2004-2011 Red Hat, Inc.  All rights reserved.
6**
7**  This copyrighted material is made available to anyone wishing to use,
8**  modify, copy, or redistribute it subject to the terms and conditions
9**  of the GNU General Public License v.2.
10**
11*******************************************************************************
12******************************************************************************/
13
14#include "dlm_internal.h"
15#include "lockspace.h"
16#include "member.h"
17#include "dir.h"
18#include "ast.h"
19#include "recover.h"
20#include "lowcomms.h"
21#include "lock.h"
22#include "requestqueue.h"
23#include "recoverd.h"
24
25
26/* If the start for which we're re-enabling locking (seq) has been superseded
27   by a newer stop (ls_recover_seq), we need to leave locking disabled.
28
29   We suspend dlm_recv threads here to avoid the race where dlm_recv a) sees
30   locking stopped and b) adds a message to the requestqueue, but dlm_recoverd
31   enables locking and clears the requestqueue between a and b. */
32
33static int enable_locking(struct dlm_ls *ls, uint64_t seq)
34{
35	int error = -EINTR;
36
37	down_write(&ls->ls_recv_active);
38
39	spin_lock(&ls->ls_recover_lock);
40	if (ls->ls_recover_seq == seq) {
41		set_bit(LSFL_RUNNING, &ls->ls_flags);
42		/* unblocks processes waiting to enter the dlm */
43		up_write(&ls->ls_in_recovery);
44		error = 0;
45	}
46	spin_unlock(&ls->ls_recover_lock);
47
48	up_write(&ls->ls_recv_active);
49	return error;
50}
51
52static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
53{
54	unsigned long start;
55	int error, neg = 0;
56
57	log_debug(ls, "dlm_recover %llx", (unsigned long long)rv->seq);
58
59	mutex_lock(&ls->ls_recoverd_active);
60
61	dlm_callback_suspend(ls);
62
63	/*
64	 * Free non-master tossed rsb's.  Master rsb's are kept on toss
65	 * list and put on root list to be included in resdir recovery.
66	 */
67
68	dlm_clear_toss_list(ls);
69
70	/*
71	 * This list of root rsb's will be the basis of most of the recovery
72	 * routines.
73	 */
74
75	dlm_create_root_list(ls);
76
77	/*
78	 * Add or remove nodes from the lockspace's ls_nodes list.
79	 */
80
81	error = dlm_recover_members(ls, rv, &neg);
82	if (error) {
83		log_debug(ls, "dlm_recover_members error %d", error);
84		goto fail;
85	}
86
87	dlm_set_recover_status(ls, DLM_RS_NODES);
88
89	error = dlm_recover_members_wait(ls);
90	if (error) {
91		log_debug(ls, "dlm_recover_members_wait error %d", error);
92		goto fail;
93	}
94
95	start = jiffies;
96
97	/*
98	 * Rebuild our own share of the directory by collecting from all other
99	 * nodes their master rsb names that hash to us.
100	 */
101
102	error = dlm_recover_directory(ls);
103	if (error) {
104		log_debug(ls, "dlm_recover_directory error %d", error);
105		goto fail;
106	}
107
108	dlm_set_recover_status(ls, DLM_RS_DIR);
109
110	error = dlm_recover_directory_wait(ls);
111	if (error) {
112		log_debug(ls, "dlm_recover_directory_wait error %d", error);
113		goto fail;
114	}
115
116	/*
117	 * We may have outstanding operations that are waiting for a reply from
118	 * a failed node.  Mark these to be resent after recovery.  Unlock and
119	 * cancel ops can just be completed.
120	 */
121
122	dlm_recover_waiters_pre(ls);
123
124	error = dlm_recovery_stopped(ls);
125	if (error)
126		goto fail;
127
128	if (neg || dlm_no_directory(ls)) {
129		/*
130		 * Clear lkb's for departed nodes.
131		 */
132
133		dlm_purge_locks(ls);
134
135		/*
136		 * Get new master nodeid's for rsb's that were mastered on
137		 * departed nodes.
138		 */
139
140		error = dlm_recover_masters(ls);
141		if (error) {
142			log_debug(ls, "dlm_recover_masters error %d", error);
143			goto fail;
144		}
145
146		/*
147		 * Send our locks on remastered rsb's to the new masters.
148		 */
149
150		error = dlm_recover_locks(ls);
151		if (error) {
152			log_debug(ls, "dlm_recover_locks error %d", error);
153			goto fail;
154		}
155
156		dlm_set_recover_status(ls, DLM_RS_LOCKS);
157
158		error = dlm_recover_locks_wait(ls);
159		if (error) {
160			log_debug(ls, "dlm_recover_locks_wait error %d", error);
161			goto fail;
162		}
163
164		/*
165		 * Finalize state in master rsb's now that all locks can be
166		 * checked.  This includes conversion resolution and lvb
167		 * settings.
168		 */
169
170		dlm_recover_rsbs(ls);
171	} else {
172		/*
173		 * Other lockspace members may be going through the "neg" steps
174		 * while also adding us to the lockspace, in which case they'll
175		 * be doing the recover_locks (RS_LOCKS) barrier.
176		 */
177		dlm_set_recover_status(ls, DLM_RS_LOCKS);
178
179		error = dlm_recover_locks_wait(ls);
180		if (error) {
181			log_debug(ls, "dlm_recover_locks_wait error %d", error);
182			goto fail;
183		}
184	}
185
186	dlm_release_root_list(ls);
187
188	/*
189	 * Purge directory-related requests that are saved in requestqueue.
190	 * All dir requests from before recovery are invalid now due to the dir
191	 * rebuild and will be resent by the requesting nodes.
192	 */
193
194	dlm_purge_requestqueue(ls);
195
196	dlm_set_recover_status(ls, DLM_RS_DONE);
197
198	error = dlm_recover_done_wait(ls);
199	if (error) {
200		log_debug(ls, "dlm_recover_done_wait error %d", error);
201		goto fail;
202	}
203
204	dlm_clear_members_gone(ls);
205
206	dlm_adjust_timeouts(ls);
207
208	dlm_callback_resume(ls);
209
210	error = enable_locking(ls, rv->seq);
211	if (error) {
212		log_debug(ls, "enable_locking error %d", error);
213		goto fail;
214	}
215
216	error = dlm_process_requestqueue(ls);
217	if (error) {
218		log_debug(ls, "dlm_process_requestqueue error %d", error);
219		goto fail;
220	}
221
222	error = dlm_recover_waiters_post(ls);
223	if (error) {
224		log_debug(ls, "dlm_recover_waiters_post error %d", error);
225		goto fail;
226	}
227
228	dlm_grant_after_purge(ls);
229
230	log_debug(ls, "dlm_recover %llx generation %u done: %u ms",
231		  (unsigned long long)rv->seq, ls->ls_generation,
232		  jiffies_to_msecs(jiffies - start));
233	mutex_unlock(&ls->ls_recoverd_active);
234
235	dlm_lsop_recover_done(ls);
236	return 0;
237
238 fail:
239	dlm_release_root_list(ls);
240	log_debug(ls, "dlm_recover %llx error %d",
241		  (unsigned long long)rv->seq, error);
242	mutex_unlock(&ls->ls_recoverd_active);
243	return error;
244}
245
246/* The dlm_ls_start() that created the rv we take here may already have been
247   stopped via dlm_ls_stop(); in that case we need to leave the RECOVERY_STOP
248   flag set. */
249
250static void do_ls_recovery(struct dlm_ls *ls)
251{
252	struct dlm_recover *rv = NULL;
253
254	spin_lock(&ls->ls_recover_lock);
255	rv = ls->ls_recover_args;
256	ls->ls_recover_args = NULL;
257	if (rv && ls->ls_recover_seq == rv->seq)
258		clear_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
259	spin_unlock(&ls->ls_recover_lock);
260
261	if (rv) {
262		ls_recover(ls, rv);
263		kfree(rv->nodes);
264		kfree(rv);
265	}
266}
267
268static int dlm_recoverd(void *arg)
269{
270	struct dlm_ls *ls;
271
272	ls = dlm_find_lockspace_local(arg);
273	if (!ls) {
274		log_print("dlm_recoverd: no lockspace %p", arg);
275		return -1;
276	}
277
278	while (!kthread_should_stop()) {
279		set_current_state(TASK_INTERRUPTIBLE);
280		if (!test_bit(LSFL_WORK, &ls->ls_flags))
281			schedule();
282		set_current_state(TASK_RUNNING);
283
284		if (test_and_clear_bit(LSFL_WORK, &ls->ls_flags))
285			do_ls_recovery(ls);
286	}
287
288	dlm_put_lockspace(ls);
289	return 0;
290}
291
292void dlm_recoverd_kick(struct dlm_ls *ls)
293{
294	set_bit(LSFL_WORK, &ls->ls_flags);
295	wake_up_process(ls->ls_recoverd_task);
296}
297
298int dlm_recoverd_start(struct dlm_ls *ls)
299{
300	struct task_struct *p;
301	int error = 0;
302
303	p = kthread_run(dlm_recoverd, ls, "dlm_recoverd");
304	if (IS_ERR(p))
305		error = PTR_ERR(p);
306	else
307                ls->ls_recoverd_task = p;
308	return error;
309}
310
311void dlm_recoverd_stop(struct dlm_ls *ls)
312{
313	kthread_stop(ls->ls_recoverd_task);
314}
315
316void dlm_recoverd_suspend(struct dlm_ls *ls)
317{
318	wake_up(&ls->ls_wait_general);
319	mutex_lock(&ls->ls_recoverd_active);
320}
321
322void dlm_recoverd_resume(struct dlm_ls *ls)
323{
324	mutex_unlock(&ls->ls_recoverd_active);
325}
326
327