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 
dlm_dump_lkb_callbacks(struct dlm_lkb * lkb)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 
dlm_add_lkb_callback(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags,uint64_t seq)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 
dlm_rem_lkb_callback(struct dlm_ls * ls,struct dlm_lkb * lkb,struct dlm_callback * cb,int * resid)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 
dlm_add_cb(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags)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 	if (!dlm_cb_seq)
185 		new_seq = ++dlm_cb_seq;
186 	spin_unlock(&dlm_cb_seq_spin);
187 
188 	if (lkb->lkb_flags & DLM_IFL_USER) {
189 		dlm_user_add_ast(lkb, flags, mode, status, sbflags, new_seq);
190 		return;
191 	}
192 
193 	mutex_lock(&lkb->lkb_cb_mutex);
194 	prev_seq = lkb->lkb_callbacks[0].seq;
195 
196 	rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, new_seq);
197 	if (rv < 0)
198 		goto out;
199 
200 	if (!prev_seq) {
201 		kref_get(&lkb->lkb_ref);
202 
203 		mutex_lock(&ls->ls_cb_mutex);
204 		if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
205 			list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
206 		} else {
207 			queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
208 		}
209 		mutex_unlock(&ls->ls_cb_mutex);
210 	}
211  out:
212 	mutex_unlock(&lkb->lkb_cb_mutex);
213 }
214 
dlm_callback_work(struct work_struct * work)215 void dlm_callback_work(struct work_struct *work)
216 {
217 	struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
218 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
219 	void (*castfn) (void *astparam);
220 	void (*bastfn) (void *astparam, int mode);
221 	struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
222 	int i, rv, resid;
223 
224 	memset(&callbacks, 0, sizeof(callbacks));
225 
226 	mutex_lock(&lkb->lkb_cb_mutex);
227 	if (!lkb->lkb_callbacks[0].seq) {
228 		/* no callback work exists, shouldn't happen */
229 		log_error(ls, "dlm_callback_work %x no work", lkb->lkb_id);
230 		dlm_print_lkb(lkb);
231 		dlm_dump_lkb_callbacks(lkb);
232 	}
233 
234 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
235 		rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
236 		if (rv < 0)
237 			break;
238 	}
239 
240 	if (resid) {
241 		/* cbs remain, loop should have removed all, shouldn't happen */
242 		log_error(ls, "dlm_callback_work %x resid %d", lkb->lkb_id,
243 			  resid);
244 		dlm_print_lkb(lkb);
245 		dlm_dump_lkb_callbacks(lkb);
246 	}
247 	mutex_unlock(&lkb->lkb_cb_mutex);
248 
249 	castfn = lkb->lkb_astfn;
250 	bastfn = lkb->lkb_bastfn;
251 
252 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
253 		if (!callbacks[i].seq)
254 			break;
255 		if (callbacks[i].flags & DLM_CB_SKIP) {
256 			continue;
257 		} else if (callbacks[i].flags & DLM_CB_BAST) {
258 			bastfn(lkb->lkb_astparam, callbacks[i].mode);
259 		} else if (callbacks[i].flags & DLM_CB_CAST) {
260 			lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
261 			lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
262 			castfn(lkb->lkb_astparam);
263 		}
264 	}
265 
266 	/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
267 	dlm_put_lkb(lkb);
268 }
269 
dlm_callback_start(struct dlm_ls * ls)270 int dlm_callback_start(struct dlm_ls *ls)
271 {
272 	ls->ls_callback_wq = alloc_workqueue("dlm_callback",
273 					     WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
274 	if (!ls->ls_callback_wq) {
275 		log_print("can't start dlm_callback workqueue");
276 		return -ENOMEM;
277 	}
278 	return 0;
279 }
280 
dlm_callback_stop(struct dlm_ls * ls)281 void dlm_callback_stop(struct dlm_ls *ls)
282 {
283 	if (ls->ls_callback_wq)
284 		destroy_workqueue(ls->ls_callback_wq);
285 }
286 
dlm_callback_suspend(struct dlm_ls * ls)287 void dlm_callback_suspend(struct dlm_ls *ls)
288 {
289 	mutex_lock(&ls->ls_cb_mutex);
290 	set_bit(LSFL_CB_DELAY, &ls->ls_flags);
291 	mutex_unlock(&ls->ls_cb_mutex);
292 
293 	if (ls->ls_callback_wq)
294 		flush_workqueue(ls->ls_callback_wq);
295 }
296 
297 #define MAX_CB_QUEUE 25
298 
dlm_callback_resume(struct dlm_ls * ls)299 void dlm_callback_resume(struct dlm_ls *ls)
300 {
301 	struct dlm_lkb *lkb, *safe;
302 	int count = 0;
303 
304 	clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
305 
306 	if (!ls->ls_callback_wq)
307 		return;
308 
309 more:
310 	mutex_lock(&ls->ls_cb_mutex);
311 	list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
312 		list_del_init(&lkb->lkb_cb_list);
313 		queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
314 		count++;
315 		if (count == MAX_CB_QUEUE)
316 			break;
317 	}
318 	mutex_unlock(&ls->ls_cb_mutex);
319 
320 	if (count)
321 		log_rinfo(ls, "dlm_callback_resume %d", count);
322 	if (count == MAX_CB_QUEUE) {
323 		count = 0;
324 		cond_resched();
325 		goto more;
326 	}
327 }
328 
329