xref: /linux/fs/dlm/ast.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5 **  Copyright (C) 2004-2010 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 "lock.h"
16 #include "user.h"
17 #include "ast.h"
18 
19 static uint64_t dlm_cb_seq;
20 static DEFINE_SPINLOCK(dlm_cb_seq_spin);
21 
22 static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
23 {
24 	int i;
25 
26 	log_print("last_bast %x %llu flags %x mode %d sb %d %x",
27 		  lkb->lkb_id,
28 		  (unsigned long long)lkb->lkb_last_bast.seq,
29 		  lkb->lkb_last_bast.flags,
30 		  lkb->lkb_last_bast.mode,
31 		  lkb->lkb_last_bast.sb_status,
32 		  lkb->lkb_last_bast.sb_flags);
33 
34 	log_print("last_cast %x %llu flags %x mode %d sb %d %x",
35 		  lkb->lkb_id,
36 		  (unsigned long long)lkb->lkb_last_cast.seq,
37 		  lkb->lkb_last_cast.flags,
38 		  lkb->lkb_last_cast.mode,
39 		  lkb->lkb_last_cast.sb_status,
40 		  lkb->lkb_last_cast.sb_flags);
41 
42 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
43 		log_print("cb %x %llu flags %x mode %d sb %d %x",
44 			  lkb->lkb_id,
45 			  (unsigned long long)lkb->lkb_callbacks[i].seq,
46 			  lkb->lkb_callbacks[i].flags,
47 			  lkb->lkb_callbacks[i].mode,
48 			  lkb->lkb_callbacks[i].sb_status,
49 			  lkb->lkb_callbacks[i].sb_flags);
50 	}
51 }
52 
53 int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
54 			 int status, uint32_t sbflags, uint64_t seq)
55 {
56 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
57 	uint64_t prev_seq;
58 	int prev_mode;
59 	int i, rv;
60 
61 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
62 		if (lkb->lkb_callbacks[i].seq)
63 			continue;
64 
65 		/*
66 		 * Suppress some redundant basts here, do more on removal.
67 		 * Don't even add a bast if the callback just before it
68 		 * is a bast for the same mode or a more restrictive mode.
69 		 * (the addional > PR check is needed for PR/CW inversion)
70 		 */
71 
72 		if ((i > 0) && (flags & DLM_CB_BAST) &&
73 		    (lkb->lkb_callbacks[i-1].flags & DLM_CB_BAST)) {
74 
75 			prev_seq = lkb->lkb_callbacks[i-1].seq;
76 			prev_mode = lkb->lkb_callbacks[i-1].mode;
77 
78 			if ((prev_mode == mode) ||
79 			    (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
80 
81 				log_debug(ls, "skip %x add bast %llu mode %d "
82 					  "for bast %llu mode %d",
83 					  lkb->lkb_id,
84 					  (unsigned long long)seq,
85 					  mode,
86 					  (unsigned long long)prev_seq,
87 					  prev_mode);
88 				rv = 0;
89 				goto out;
90 			}
91 		}
92 
93 		lkb->lkb_callbacks[i].seq = seq;
94 		lkb->lkb_callbacks[i].flags = flags;
95 		lkb->lkb_callbacks[i].mode = mode;
96 		lkb->lkb_callbacks[i].sb_status = status;
97 		lkb->lkb_callbacks[i].sb_flags = (sbflags & 0x000000FF);
98 		rv = 0;
99 		break;
100 	}
101 
102 	if (i == DLM_CALLBACKS_SIZE) {
103 		log_error(ls, "no callbacks %x %llu flags %x mode %d sb %d %x",
104 			  lkb->lkb_id, (unsigned long long)seq,
105 			  flags, mode, status, sbflags);
106 		dlm_dump_lkb_callbacks(lkb);
107 		rv = -1;
108 		goto out;
109 	}
110  out:
111 	return rv;
112 }
113 
114 int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
115 			 struct dlm_callback *cb, int *resid)
116 {
117 	int i, rv;
118 
119 	*resid = 0;
120 
121 	if (!lkb->lkb_callbacks[0].seq) {
122 		rv = -ENOENT;
123 		goto out;
124 	}
125 
126 	/* oldest undelivered cb is callbacks[0] */
127 
128 	memcpy(cb, &lkb->lkb_callbacks[0], sizeof(struct dlm_callback));
129 	memset(&lkb->lkb_callbacks[0], 0, sizeof(struct dlm_callback));
130 
131 	/* shift others down */
132 
133 	for (i = 1; i < DLM_CALLBACKS_SIZE; i++) {
134 		if (!lkb->lkb_callbacks[i].seq)
135 			break;
136 		memcpy(&lkb->lkb_callbacks[i-1], &lkb->lkb_callbacks[i],
137 		       sizeof(struct dlm_callback));
138 		memset(&lkb->lkb_callbacks[i], 0, sizeof(struct dlm_callback));
139 		(*resid)++;
140 	}
141 
142 	/* if cb is a bast, it should be skipped if the blocking mode is
143 	   compatible with the last granted mode */
144 
145 	if ((cb->flags & DLM_CB_BAST) && lkb->lkb_last_cast.seq) {
146 		if (dlm_modes_compat(cb->mode, lkb->lkb_last_cast.mode)) {
147 			cb->flags |= DLM_CB_SKIP;
148 
149 			log_debug(ls, "skip %x bast %llu mode %d "
150 				  "for cast %llu mode %d",
151 				  lkb->lkb_id,
152 				  (unsigned long long)cb->seq,
153 				  cb->mode,
154 				  (unsigned long long)lkb->lkb_last_cast.seq,
155 				  lkb->lkb_last_cast.mode);
156 			rv = 0;
157 			goto out;
158 		}
159 	}
160 
161 	if (cb->flags & DLM_CB_CAST) {
162 		memcpy(&lkb->lkb_last_cast, cb, sizeof(struct dlm_callback));
163 		lkb->lkb_last_cast_time = ktime_get();
164 	}
165 
166 	if (cb->flags & DLM_CB_BAST) {
167 		memcpy(&lkb->lkb_last_bast, cb, sizeof(struct dlm_callback));
168 		lkb->lkb_last_bast_time = ktime_get();
169 	}
170 	rv = 0;
171  out:
172 	return rv;
173 }
174 
175 void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
176 		uint32_t sbflags)
177 {
178 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
179 	uint64_t new_seq, prev_seq;
180 	int rv;
181 
182 	spin_lock(&dlm_cb_seq_spin);
183 	new_seq = ++dlm_cb_seq;
184 	spin_unlock(&dlm_cb_seq_spin);
185 
186 	if (lkb->lkb_flags & DLM_IFL_USER) {
187 		dlm_user_add_ast(lkb, flags, mode, status, sbflags, new_seq);
188 		return;
189 	}
190 
191 	mutex_lock(&lkb->lkb_cb_mutex);
192 	prev_seq = lkb->lkb_callbacks[0].seq;
193 
194 	rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, new_seq);
195 	if (rv < 0)
196 		goto out;
197 
198 	if (!prev_seq) {
199 		kref_get(&lkb->lkb_ref);
200 
201 		if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
202 			mutex_lock(&ls->ls_cb_mutex);
203 			list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
204 			mutex_unlock(&ls->ls_cb_mutex);
205 		} else {
206 			queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
207 		}
208 	}
209  out:
210 	mutex_unlock(&lkb->lkb_cb_mutex);
211 }
212 
213 void dlm_callback_work(struct work_struct *work)
214 {
215 	struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
216 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
217 	void (*castfn) (void *astparam);
218 	void (*bastfn) (void *astparam, int mode);
219 	struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
220 	int i, rv, resid;
221 
222 	memset(&callbacks, 0, sizeof(callbacks));
223 
224 	mutex_lock(&lkb->lkb_cb_mutex);
225 	if (!lkb->lkb_callbacks[0].seq) {
226 		/* no callback work exists, shouldn't happen */
227 		log_error(ls, "dlm_callback_work %x no work", lkb->lkb_id);
228 		dlm_print_lkb(lkb);
229 		dlm_dump_lkb_callbacks(lkb);
230 	}
231 
232 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
233 		rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
234 		if (rv < 0)
235 			break;
236 	}
237 
238 	if (resid) {
239 		/* cbs remain, loop should have removed all, shouldn't happen */
240 		log_error(ls, "dlm_callback_work %x resid %d", lkb->lkb_id,
241 			  resid);
242 		dlm_print_lkb(lkb);
243 		dlm_dump_lkb_callbacks(lkb);
244 	}
245 	mutex_unlock(&lkb->lkb_cb_mutex);
246 
247 	castfn = lkb->lkb_astfn;
248 	bastfn = lkb->lkb_bastfn;
249 
250 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
251 		if (!callbacks[i].seq)
252 			break;
253 		if (callbacks[i].flags & DLM_CB_SKIP) {
254 			continue;
255 		} else if (callbacks[i].flags & DLM_CB_BAST) {
256 			bastfn(lkb->lkb_astparam, callbacks[i].mode);
257 		} else if (callbacks[i].flags & DLM_CB_CAST) {
258 			lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
259 			lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
260 			castfn(lkb->lkb_astparam);
261 		}
262 	}
263 
264 	/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
265 	dlm_put_lkb(lkb);
266 }
267 
268 int dlm_callback_start(struct dlm_ls *ls)
269 {
270 	ls->ls_callback_wq = alloc_workqueue("dlm_callback",
271 					     WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
272 	if (!ls->ls_callback_wq) {
273 		log_print("can't start dlm_callback workqueue");
274 		return -ENOMEM;
275 	}
276 	return 0;
277 }
278 
279 void dlm_callback_stop(struct dlm_ls *ls)
280 {
281 	if (ls->ls_callback_wq)
282 		destroy_workqueue(ls->ls_callback_wq);
283 }
284 
285 void dlm_callback_suspend(struct dlm_ls *ls)
286 {
287 	set_bit(LSFL_CB_DELAY, &ls->ls_flags);
288 
289 	if (ls->ls_callback_wq)
290 		flush_workqueue(ls->ls_callback_wq);
291 }
292 
293 void dlm_callback_resume(struct dlm_ls *ls)
294 {
295 	struct dlm_lkb *lkb, *safe;
296 	int count = 0;
297 
298 	clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
299 
300 	if (!ls->ls_callback_wq)
301 		return;
302 
303 	mutex_lock(&ls->ls_cb_mutex);
304 	list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
305 		list_del_init(&lkb->lkb_cb_list);
306 		queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
307 		count++;
308 	}
309 	mutex_unlock(&ls->ls_cb_mutex);
310 
311 	if (count)
312 		log_rinfo(ls, "dlm_callback_resume %d", count);
313 }
314 
315