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