xref: /openbmc/linux/fs/dlm/requestqueue.c (revision 0a94608f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3 *******************************************************************************
4 **
5 **  Copyright (C) 2005-2007 Red Hat, Inc.  All rights reserved.
6 **
7 **
8 *******************************************************************************
9 ******************************************************************************/
10 
11 #include "dlm_internal.h"
12 #include "member.h"
13 #include "lock.h"
14 #include "dir.h"
15 #include "config.h"
16 #include "requestqueue.h"
17 
18 struct rq_entry {
19 	struct list_head list;
20 	uint32_t recover_seq;
21 	int nodeid;
22 	struct dlm_message request;
23 };
24 
25 /*
26  * Requests received while the lockspace is in recovery get added to the
27  * request queue and processed when recovery is complete.  This happens when
28  * the lockspace is suspended on some nodes before it is on others, or the
29  * lockspace is enabled on some while still suspended on others.
30  */
31 
32 void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_message *ms)
33 {
34 	struct rq_entry *e;
35 	int length = ms->m_header.h_length - sizeof(struct dlm_message);
36 
37 	e = kmalloc(sizeof(struct rq_entry) + length, GFP_NOFS);
38 	if (!e) {
39 		log_print("dlm_add_requestqueue: out of memory len %d", length);
40 		return;
41 	}
42 
43 	e->recover_seq = ls->ls_recover_seq & 0xFFFFFFFF;
44 	e->nodeid = nodeid;
45 	memcpy(&e->request, ms, ms->m_header.h_length);
46 
47 	atomic_inc(&ls->ls_requestqueue_cnt);
48 	mutex_lock(&ls->ls_requestqueue_mutex);
49 	list_add_tail(&e->list, &ls->ls_requestqueue);
50 	mutex_unlock(&ls->ls_requestqueue_mutex);
51 }
52 
53 /*
54  * Called by dlm_recoverd to process normal messages saved while recovery was
55  * happening.  Normal locking has been enabled before this is called.  dlm_recv
56  * upon receiving a message, will wait for all saved messages to be drained
57  * here before processing the message it got.  If a new dlm_ls_stop() arrives
58  * while we're processing these saved messages, it may block trying to suspend
59  * dlm_recv if dlm_recv is waiting for us in dlm_wait_requestqueue.  In that
60  * case, we don't abort since locking_stopped is still 0.  If dlm_recv is not
61  * waiting for us, then this processing may be aborted due to locking_stopped.
62  */
63 
64 int dlm_process_requestqueue(struct dlm_ls *ls)
65 {
66 	struct rq_entry *e;
67 	struct dlm_message *ms;
68 	int error = 0;
69 
70 	mutex_lock(&ls->ls_requestqueue_mutex);
71 
72 	for (;;) {
73 		if (list_empty(&ls->ls_requestqueue)) {
74 			mutex_unlock(&ls->ls_requestqueue_mutex);
75 			error = 0;
76 			break;
77 		}
78 		e = list_entry(ls->ls_requestqueue.next, struct rq_entry, list);
79 		mutex_unlock(&ls->ls_requestqueue_mutex);
80 
81 		ms = &e->request;
82 
83 		log_limit(ls, "dlm_process_requestqueue msg %d from %d "
84 			  "lkid %x remid %x result %d seq %u",
85 			  ms->m_type, ms->m_header.h_nodeid,
86 			  ms->m_lkid, ms->m_remid, ms->m_result,
87 			  e->recover_seq);
88 
89 		dlm_receive_message_saved(ls, &e->request, e->recover_seq);
90 
91 		mutex_lock(&ls->ls_requestqueue_mutex);
92 		list_del(&e->list);
93 		if (atomic_dec_and_test(&ls->ls_requestqueue_cnt))
94 			wake_up(&ls->ls_requestqueue_wait);
95 		kfree(e);
96 
97 		if (dlm_locking_stopped(ls)) {
98 			log_debug(ls, "process_requestqueue abort running");
99 			mutex_unlock(&ls->ls_requestqueue_mutex);
100 			error = -EINTR;
101 			break;
102 		}
103 		schedule();
104 	}
105 
106 	return error;
107 }
108 
109 /*
110  * After recovery is done, locking is resumed and dlm_recoverd takes all the
111  * saved requests and processes them as they would have been by dlm_recv.  At
112  * the same time, dlm_recv will start receiving new requests from remote nodes.
113  * We want to delay dlm_recv processing new requests until dlm_recoverd has
114  * finished processing the old saved requests.  We don't check for locking
115  * stopped here because dlm_ls_stop won't stop locking until it's suspended us
116  * (dlm_recv).
117  */
118 
119 void dlm_wait_requestqueue(struct dlm_ls *ls)
120 {
121 	wait_event(ls->ls_requestqueue_wait,
122 		   atomic_read(&ls->ls_requestqueue_cnt) == 0);
123 }
124 
125 static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
126 {
127 	uint32_t type = ms->m_type;
128 
129 	/* the ls is being cleaned up and freed by release_lockspace */
130 	if (!atomic_read(&ls->ls_count))
131 		return 1;
132 
133 	if (dlm_is_removed(ls, nodeid))
134 		return 1;
135 
136 	/* directory operations are always purged because the directory is
137 	   always rebuilt during recovery and the lookups resent */
138 
139 	if (type == DLM_MSG_REMOVE ||
140 	    type == DLM_MSG_LOOKUP ||
141 	    type == DLM_MSG_LOOKUP_REPLY)
142 		return 1;
143 
144 	if (!dlm_no_directory(ls))
145 		return 0;
146 
147 	return 1;
148 }
149 
150 void dlm_purge_requestqueue(struct dlm_ls *ls)
151 {
152 	struct dlm_message *ms;
153 	struct rq_entry *e, *safe;
154 
155 	mutex_lock(&ls->ls_requestqueue_mutex);
156 	list_for_each_entry_safe(e, safe, &ls->ls_requestqueue, list) {
157 		ms =  &e->request;
158 
159 		if (purge_request(ls, ms, e->nodeid)) {
160 			list_del(&e->list);
161 			if (atomic_dec_and_test(&ls->ls_requestqueue_cnt))
162 				wake_up(&ls->ls_requestqueue_wait);
163 			kfree(e);
164 		}
165 	}
166 	mutex_unlock(&ls->ls_requestqueue_mutex);
167 }
168 
169