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fix setsid() for sub-namespace /sbin/init
[linux-2.6/libata-dev.git] / fs / dlm / dir.c
blobff97ba924333fccfc7cbb9699753f194d47eda7b
1 /******************************************************************************
2 *******************************************************************************
3 **
4 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
5 ** Copyright (C) 2004-2005 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 "lockspace.h"
16 #include "member.h"
17 #include "lowcomms.h"
18 #include "rcom.h"
19 #include "config.h"
20 #include "memory.h"
21 #include "recover.h"
22 #include "util.h"
23 #include "lock.h"
24 #include "dir.h"
25
26
27 static void put_free_de(struct dlm_ls *ls, struct dlm_direntry *de)
28 {
29 spin_lock(&ls->ls_recover_list_lock);
30 list_add(&de->list, &ls->ls_recover_list);
31 spin_unlock(&ls->ls_recover_list_lock);
32 }
33
34 static struct dlm_direntry *get_free_de(struct dlm_ls *ls, int len)
35 {
36 int found = 0;
37 struct dlm_direntry *de;
38
39 spin_lock(&ls->ls_recover_list_lock);
40 list_for_each_entry(de, &ls->ls_recover_list, list) {
41 if (de->length == len) {
42 list_del(&de->list);
43 de->master_nodeid = 0;
44 memset(de->name, 0, len);
45 found = 1;
46 break;
47 }
48 }
49 spin_unlock(&ls->ls_recover_list_lock);
50
51 if (!found)
52 de = kzalloc(sizeof(struct dlm_direntry) + len, GFP_KERNEL);
53 return de;
54 }
55
56 void dlm_clear_free_entries(struct dlm_ls *ls)
57 {
58 struct dlm_direntry *de;
59
60 spin_lock(&ls->ls_recover_list_lock);
61 while (!list_empty(&ls->ls_recover_list)) {
62 de = list_entry(ls->ls_recover_list.next, struct dlm_direntry,
63 list);
64 list_del(&de->list);
65 kfree(de);
66 }
67 spin_unlock(&ls->ls_recover_list_lock);
68 }
69
70 /*
71 * We use the upper 16 bits of the hash value to select the directory node.
72 * Low bits are used for distribution of rsb's among hash buckets on each node.
73 *
74 * To give the exact range wanted (0 to num_nodes-1), we apply a modulus of
75 * num_nodes to the hash value. This value in the desired range is used as an
76 * offset into the sorted list of nodeid's to give the particular nodeid.
77 */
78
79 int dlm_hash2nodeid(struct dlm_ls *ls, uint32_t hash)
80 {
81 struct list_head *tmp;
82 struct dlm_member *memb = NULL;
83 uint32_t node, n = 0;
84 int nodeid;
85
86 if (ls->ls_num_nodes == 1) {
87 nodeid = dlm_our_nodeid();
88 goto out;
89 }
90
91 if (ls->ls_node_array) {
92 node = (hash >> 16) % ls->ls_total_weight;
93 nodeid = ls->ls_node_array[node];
94 goto out;
95 }
96
97 /* make_member_array() failed to kmalloc ls_node_array... */
98
99 node = (hash >> 16) % ls->ls_num_nodes;
100
101 list_for_each(tmp, &ls->ls_nodes) {
102 if (n++ != node)
103 continue;
104 memb = list_entry(tmp, struct dlm_member, list);
105 break;
106 }
107
108 DLM_ASSERT(memb , printk("num_nodes=%u n=%u node=%u\n",
109 ls->ls_num_nodes, n, node););
110 nodeid = memb->nodeid;
111 out:
112 return nodeid;
113 }
114
115 int dlm_dir_nodeid(struct dlm_rsb *r)
116 {
117 return dlm_hash2nodeid(r->res_ls, r->res_hash);
118 }
119
120 static inline uint32_t dir_hash(struct dlm_ls *ls, char *name, int len)
121 {
122 uint32_t val;
123
124 val = jhash(name, len, 0);
125 val &= (ls->ls_dirtbl_size - 1);
126
127 return val;
128 }
129
130 static void add_entry_to_hash(struct dlm_ls *ls, struct dlm_direntry *de)
131 {
132 uint32_t bucket;
133
134 bucket = dir_hash(ls, de->name, de->length);
135 list_add_tail(&de->list, &ls->ls_dirtbl[bucket].list);
136 }
137
138 static struct dlm_direntry *search_bucket(struct dlm_ls *ls, char *name,
139 int namelen, uint32_t bucket)
140 {
141 struct dlm_direntry *de;
142
143 list_for_each_entry(de, &ls->ls_dirtbl[bucket].list, list) {
144 if (de->length == namelen && !memcmp(name, de->name, namelen))
145 goto out;
146 }
147 de = NULL;
148 out:
149 return de;
150 }
151
152 void dlm_dir_remove_entry(struct dlm_ls *ls, int nodeid, char *name, int namelen)
153 {
154 struct dlm_direntry *de;
155 uint32_t bucket;
156
157 bucket = dir_hash(ls, name, namelen);
158
159 write_lock(&ls->ls_dirtbl[bucket].lock);
160
161 de = search_bucket(ls, name, namelen, bucket);
162
163 if (!de) {
164 log_error(ls, "remove fr %u none", nodeid);
165 goto out;
166 }
167
168 if (de->master_nodeid != nodeid) {
169 log_error(ls, "remove fr %u ID %u", nodeid, de->master_nodeid);
170 goto out;
171 }
172
173 list_del(&de->list);
174 kfree(de);
175 out:
176 write_unlock(&ls->ls_dirtbl[bucket].lock);
177 }
178
179 void dlm_dir_clear(struct dlm_ls *ls)
180 {
181 struct list_head *head;
182 struct dlm_direntry *de;
183 int i;
184
185 DLM_ASSERT(list_empty(&ls->ls_recover_list), );
186
187 for (i = 0; i < ls->ls_dirtbl_size; i++) {
188 write_lock(&ls->ls_dirtbl[i].lock);
189 head = &ls->ls_dirtbl[i].list;
190 while (!list_empty(head)) {
191 de = list_entry(head->next, struct dlm_direntry, list);
192 list_del(&de->list);
193 put_free_de(ls, de);
194 }
195 write_unlock(&ls->ls_dirtbl[i].lock);
196 }
197 }
198
199 int dlm_recover_directory(struct dlm_ls *ls)
200 {
201 struct dlm_member *memb;
202 struct dlm_direntry *de;
203 char *b, *last_name = NULL;
204 int error = -ENOMEM, last_len, count = 0;
205 uint16_t namelen;
206
207 log_debug(ls, "dlm_recover_directory");
208
209 if (dlm_no_directory(ls))
210 goto out_status;
211
212 dlm_dir_clear(ls);
213
214 last_name = kmalloc(DLM_RESNAME_MAXLEN, GFP_KERNEL);
215 if (!last_name)
216 goto out;
217
218 list_for_each_entry(memb, &ls->ls_nodes, list) {
219 memset(last_name, 0, DLM_RESNAME_MAXLEN);
220 last_len = 0;
221
222 for (;;) {
223 error = dlm_recovery_stopped(ls);
224 if (error)
225 goto out_free;
226
227 error = dlm_rcom_names(ls, memb->nodeid,
228 last_name, last_len);
229 if (error)
230 goto out_free;
231
232 schedule();
233
234 /*
235 * pick namelen/name pairs out of received buffer
236 */
237
238 b = ls->ls_recover_buf + sizeof(struct dlm_rcom);
239
240 for (;;) {
241 memcpy(&namelen, b, sizeof(uint16_t));
242 namelen = be16_to_cpu(namelen);
243 b += sizeof(uint16_t);
244
245 /* namelen of 0xFFFFF marks end of names for
246 this node; namelen of 0 marks end of the
247 buffer */
248
249 if (namelen == 0xFFFF)
250 goto done;
251 if (!namelen)
252 break;
253
254 error = -ENOMEM;
255 de = get_free_de(ls, namelen);
256 if (!de)
257 goto out_free;
258
259 de->master_nodeid = memb->nodeid;
260 de->length = namelen;
261 last_len = namelen;
262 memcpy(de->name, b, namelen);
263 memcpy(last_name, b, namelen);
264 b += namelen;
265
266 add_entry_to_hash(ls, de);
267 count++;
268 }
269 }
270 done:
271 ;
272 }
273
274 out_status:
275 error = 0;
276 dlm_set_recover_status(ls, DLM_RS_DIR);
277 log_debug(ls, "dlm_recover_directory %d entries", count);
278 out_free:
279 kfree(last_name);
280 out:
281 dlm_clear_free_entries(ls);
282 return error;
283 }
284
285 static int get_entry(struct dlm_ls *ls, int nodeid, char *name,
286 int namelen, int *r_nodeid)
287 {
288 struct dlm_direntry *de, *tmp;
289 uint32_t bucket;
290
291 bucket = dir_hash(ls, name, namelen);
292
293 write_lock(&ls->ls_dirtbl[bucket].lock);
294 de = search_bucket(ls, name, namelen, bucket);
295 if (de) {
296 *r_nodeid = de->master_nodeid;
297 write_unlock(&ls->ls_dirtbl[bucket].lock);
298 if (*r_nodeid == nodeid)
299 return -EEXIST;
300 return 0;
301 }
302
303 write_unlock(&ls->ls_dirtbl[bucket].lock);
304
305 de = kzalloc(sizeof(struct dlm_direntry) + namelen, GFP_KERNEL);
306 if (!de)
307 return -ENOMEM;
308
309 de->master_nodeid = nodeid;
310 de->length = namelen;
311 memcpy(de->name, name, namelen);
312
313 write_lock(&ls->ls_dirtbl[bucket].lock);
314 tmp = search_bucket(ls, name, namelen, bucket);
315 if (tmp) {
316 kfree(de);
317 de = tmp;
318 } else {
319 list_add_tail(&de->list, &ls->ls_dirtbl[bucket].list);
320 }
321 *r_nodeid = de->master_nodeid;
322 write_unlock(&ls->ls_dirtbl[bucket].lock);
323 return 0;
324 }
325
326 int dlm_dir_lookup(struct dlm_ls *ls, int nodeid, char *name, int namelen,
327 int *r_nodeid)
328 {
329 return get_entry(ls, nodeid, name, namelen, r_nodeid);
330 }
331
332 static struct dlm_rsb *find_rsb_root(struct dlm_ls *ls, char *name, int len)
333 {
334 struct dlm_rsb *r;
335
336 down_read(&ls->ls_root_sem);
337 list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
338 if (len == r->res_length && !memcmp(name, r->res_name, len)) {
339 up_read(&ls->ls_root_sem);
340 return r;
341 }
342 }
343 up_read(&ls->ls_root_sem);
344 return NULL;
345 }
346
347 /* Find the rsb where we left off (or start again), then send rsb names
348 for rsb's we're master of and whose directory node matches the requesting
349 node. inbuf is the rsb name last sent, inlen is the name's length */
350
351 void dlm_copy_master_names(struct dlm_ls *ls, char *inbuf, int inlen,
352 char *outbuf, int outlen, int nodeid)
353 {
354 struct list_head *list;
355 struct dlm_rsb *r;
356 int offset = 0, dir_nodeid;
357 uint16_t be_namelen;
358
359 down_read(&ls->ls_root_sem);
360
361 if (inlen > 1) {
362 r = find_rsb_root(ls, inbuf, inlen);
363 if (!r) {
364 inbuf[inlen - 1] = '\0';
365 log_error(ls, "copy_master_names from %d start %d %s",
366 nodeid, inlen, inbuf);
367 goto out;
368 }
369 list = r->res_root_list.next;
370 } else {
371 list = ls->ls_root_list.next;
372 }
373
374 for (offset = 0; list != &ls->ls_root_list; list = list->next) {
375 r = list_entry(list, struct dlm_rsb, res_root_list);
376 if (r->res_nodeid)
377 continue;
378
379 dir_nodeid = dlm_dir_nodeid(r);
380 if (dir_nodeid != nodeid)
381 continue;
382
383 /*
384 * The block ends when we can't fit the following in the
385 * remaining buffer space:
386 * namelen (uint16_t) +
387 * name (r->res_length) +
388 * end-of-block record 0x0000 (uint16_t)
389 */
390
391 if (offset + sizeof(uint16_t)*2 + r->res_length > outlen) {
392 /* Write end-of-block record */
393 be_namelen = 0;
394 memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
395 offset += sizeof(uint16_t);
396 goto out;
397 }
398
399 be_namelen = cpu_to_be16(r->res_length);
400 memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
401 offset += sizeof(uint16_t);
402 memcpy(outbuf + offset, r->res_name, r->res_length);
403 offset += r->res_length;
404 }
405
406 /*
407 * If we've reached the end of the list (and there's room) write a
408 * terminating record.
409 */
410
411 if ((list == &ls->ls_root_list) &&
412 (offset + sizeof(uint16_t) <= outlen)) {
413 be_namelen = 0xFFFF;
414 memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
415 offset += sizeof(uint16_t);
416 }
417
418 out:
419 up_read(&ls->ls_root_sem);
420 }
421
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