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 
18 static uint64_t			dlm_cb_seq;
19 static spinlock_t		dlm_cb_seq_spin;
20 
dlm_dump_lkb_callbacks(struct dlm_lkb * lkb)21 static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
22 {
23 	int i;
24 
25 	log_print("last_bast %x %llu flags %x mode %d sb %d %x",
26 		  lkb->lkb_id,
27 		  (unsigned long long)lkb->lkb_last_bast.seq,
28 		  lkb->lkb_last_bast.flags,
29 		  lkb->lkb_last_bast.mode,
30 		  lkb->lkb_last_bast.sb_status,
31 		  lkb->lkb_last_bast.sb_flags);
32 
33 	log_print("last_cast %x %llu flags %x mode %d sb %d %x",
34 		  lkb->lkb_id,
35 		  (unsigned long long)lkb->lkb_last_cast.seq,
36 		  lkb->lkb_last_cast.flags,
37 		  lkb->lkb_last_cast.mode,
38 		  lkb->lkb_last_cast.sb_status,
39 		  lkb->lkb_last_cast.sb_flags);
40 
41 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
42 		log_print("cb %x %llu flags %x mode %d sb %d %x",
43 			  lkb->lkb_id,
44 			  (unsigned long long)lkb->lkb_callbacks[i].seq,
45 			  lkb->lkb_callbacks[i].flags,
46 			  lkb->lkb_callbacks[i].mode,
47 			  lkb->lkb_callbacks[i].sb_status,
48 			  lkb->lkb_callbacks[i].sb_flags);
49 	}
50 }
51 
dlm_add_lkb_callback(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags,uint64_t seq)52 int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
53 			 int status, uint32_t sbflags, uint64_t seq)
54 {
55 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
56 	uint64_t prev_seq;
57 	int prev_mode;
58 	int i, rv;
59 
60 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
61 		if (lkb->lkb_callbacks[i].seq)
62 			continue;
63 
64 		/*
65 		 * Suppress some redundant basts here, do more on removal.
66 		 * Don't even add a bast if the callback just before it
67 		 * is a bast for the same mode or a more restrictive mode.
68 		 * (the addional > PR check is needed for PR/CW inversion)
69 		 */
70 
71 		if ((i > 0) && (flags & DLM_CB_BAST) &&
72 		    (lkb->lkb_callbacks[i-1].flags & DLM_CB_BAST)) {
73 
74 			prev_seq = lkb->lkb_callbacks[i-1].seq;
75 			prev_mode = lkb->lkb_callbacks[i-1].mode;
76 
77 			if ((prev_mode == mode) ||
78 			    (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
79 
80 				log_debug(ls, "skip %x add bast %llu mode %d "
81 					  "for bast %llu mode %d",
82 					  lkb->lkb_id,
83 					  (unsigned long long)seq,
84 					  mode,
85 					  (unsigned long long)prev_seq,
86 					  prev_mode);
87 				rv = 0;
88 				goto out;
89 			}
90 		}
91 
92 		lkb->lkb_callbacks[i].seq = seq;
93 		lkb->lkb_callbacks[i].flags = flags;
94 		lkb->lkb_callbacks[i].mode = mode;
95 		lkb->lkb_callbacks[i].sb_status = status;
96 		lkb->lkb_callbacks[i].sb_flags = (sbflags & 0x000000FF);
97 		rv = 0;
98 		break;
99 	}
100 
101 	if (i == DLM_CALLBACKS_SIZE) {
102 		log_error(ls, "no callbacks %x %llu flags %x mode %d sb %d %x",
103 			  lkb->lkb_id, (unsigned long long)seq,
104 			  flags, mode, status, sbflags);
105 		dlm_dump_lkb_callbacks(lkb);
106 		rv = -1;
107 		goto out;
108 	}
109  out:
110 	return rv;
111 }
112 
dlm_rem_lkb_callback(struct dlm_ls * ls,struct dlm_lkb * lkb,struct dlm_callback * cb,int * resid)113 int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
114 			 struct dlm_callback *cb, int *resid)
115 {
116 	int i, rv;
117 
118 	*resid = 0;
119 
120 	if (!lkb->lkb_callbacks[0].seq) {
121 		rv = -ENOENT;
122 		goto out;
123 	}
124 
125 	/* oldest undelivered cb is callbacks[0] */
126 
127 	memcpy(cb, &lkb->lkb_callbacks[0], sizeof(struct dlm_callback));
128 	memset(&lkb->lkb_callbacks[0], 0, sizeof(struct dlm_callback));
129 
130 	/* shift others down */
131 
132 	for (i = 1; i < DLM_CALLBACKS_SIZE; i++) {
133 		if (!lkb->lkb_callbacks[i].seq)
134 			break;
135 		memcpy(&lkb->lkb_callbacks[i-1], &lkb->lkb_callbacks[i],
136 		       sizeof(struct dlm_callback));
137 		memset(&lkb->lkb_callbacks[i], 0, sizeof(struct dlm_callback));
138 		(*resid)++;
139 	}
140 
141 	/* if cb is a bast, it should be skipped if the blocking mode is
142 	   compatible with the last granted mode */
143 
144 	if ((cb->flags & DLM_CB_BAST) && lkb->lkb_last_cast.seq) {
145 		if (dlm_modes_compat(cb->mode, lkb->lkb_last_cast.mode)) {
146 			cb->flags |= DLM_CB_SKIP;
147 
148 			log_debug(ls, "skip %x bast %llu mode %d "
149 				  "for cast %llu mode %d",
150 				  lkb->lkb_id,
151 				  (unsigned long long)cb->seq,
152 				  cb->mode,
153 				  (unsigned long long)lkb->lkb_last_cast.seq,
154 				  lkb->lkb_last_cast.mode);
155 			rv = 0;
156 			goto out;
157 		}
158 	}
159 
160 	if (cb->flags & DLM_CB_CAST) {
161 		memcpy(&lkb->lkb_last_cast, cb, sizeof(struct dlm_callback));
162 		lkb->lkb_last_cast_time = ktime_get();
163 	}
164 
165 	if (cb->flags & DLM_CB_BAST) {
166 		memcpy(&lkb->lkb_last_bast, cb, sizeof(struct dlm_callback));
167 		lkb->lkb_last_bast_time = ktime_get();
168 	}
169 	rv = 0;
170  out:
171 	return rv;
172 }
173 
dlm_add_cb(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags)174 void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
175 		uint32_t sbflags)
176 {
177 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
178 	uint64_t new_seq, prev_seq;
179 	int rv;
180 
181 	spin_lock(&dlm_cb_seq_spin);
182 	new_seq = ++dlm_cb_seq;
183 	spin_unlock(&dlm_cb_seq_spin);
184 
185 	if (lkb->lkb_flags & DLM_IFL_USER) {
186 		dlm_user_add_ast(lkb, flags, mode, status, sbflags, new_seq);
187 		return;
188 	}
189 
190 	mutex_lock(&lkb->lkb_cb_mutex);
191 	prev_seq = lkb->lkb_callbacks[0].seq;
192 
193 	rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, new_seq);
194 	if (rv < 0)
195 		goto out;
196 
197 	if (!prev_seq) {
198 		kref_get(&lkb->lkb_ref);
199 
200 		if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
201 			mutex_lock(&ls->ls_cb_mutex);
202 			list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
203 			mutex_unlock(&ls->ls_cb_mutex);
204 		} else {
205 			queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
206 		}
207 	}
208  out:
209 	mutex_unlock(&lkb->lkb_cb_mutex);
210 }
211 
dlm_callback_work(struct work_struct * work)212 void dlm_callback_work(struct work_struct *work)
213 {
214 	struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
215 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
216 	void (*castfn) (void *astparam);
217 	void (*bastfn) (void *astparam, int mode);
218 	struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
219 	int i, rv, resid;
220 
221 	memset(&callbacks, 0, sizeof(callbacks));
222 
223 	mutex_lock(&lkb->lkb_cb_mutex);
224 	if (!lkb->lkb_callbacks[0].seq) {
225 		/* no callback work exists, shouldn't happen */
226 		log_error(ls, "dlm_callback_work %x no work", lkb->lkb_id);
227 		dlm_print_lkb(lkb);
228 		dlm_dump_lkb_callbacks(lkb);
229 	}
230 
231 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
232 		rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
233 		if (rv < 0)
234 			break;
235 	}
236 
237 	if (resid) {
238 		/* cbs remain, loop should have removed all, shouldn't happen */
239 		log_error(ls, "dlm_callback_work %x resid %d", lkb->lkb_id,
240 			  resid);
241 		dlm_print_lkb(lkb);
242 		dlm_dump_lkb_callbacks(lkb);
243 	}
244 	mutex_unlock(&lkb->lkb_cb_mutex);
245 
246 	castfn = lkb->lkb_astfn;
247 	bastfn = lkb->lkb_bastfn;
248 
249 	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
250 		if (!callbacks[i].seq)
251 			break;
252 		if (callbacks[i].flags & DLM_CB_SKIP) {
253 			continue;
254 		} else if (callbacks[i].flags & DLM_CB_BAST) {
255 			bastfn(lkb->lkb_astparam, callbacks[i].mode);
256 		} else if (callbacks[i].flags & DLM_CB_CAST) {
257 			lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
258 			lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
259 			castfn(lkb->lkb_astparam);
260 		}
261 	}
262 
263 	/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
264 	dlm_put_lkb(lkb);
265 }
266 
dlm_callback_start(struct dlm_ls * ls)267 int dlm_callback_start(struct dlm_ls *ls)
268 {
269 	ls->ls_callback_wq = alloc_workqueue("dlm_callback",
270 					     WQ_UNBOUND |
271 					     WQ_MEM_RECLAIM |
272 					     WQ_NON_REENTRANT,
273 					     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 	set_bit(LSFL_CB_DELAY, &ls->ls_flags);
290 
291 	if (ls->ls_callback_wq)
292 		flush_workqueue(ls->ls_callback_wq);
293 }
294 
dlm_callback_resume(struct dlm_ls * ls)295 void dlm_callback_resume(struct dlm_ls *ls)
296 {
297 	struct dlm_lkb *lkb, *safe;
298 	int count = 0;
299 
300 	clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
301 
302 	if (!ls->ls_callback_wq)
303 		return;
304 
305 	mutex_lock(&ls->ls_cb_mutex);
306 	list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
307 		list_del_init(&lkb->lkb_cb_list);
308 		queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
309 		count++;
310 	}
311 	mutex_unlock(&ls->ls_cb_mutex);
312 
313 	log_debug(ls, "dlm_callback_resume %d", count);
314 }
315 
316