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