1 /* Global fscache object list maintainer and viewer
2 *
3 * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12 #define FSCACHE_DEBUG_LEVEL COOKIE
13 #include <linux/module.h>
14 #include <linux/seq_file.h>
15 #include <linux/slab.h>
16 #include <linux/key.h>
17 #include <keys/user-type.h>
18 #include "internal.h"
19
20 static struct rb_root fscache_object_list;
21 static DEFINE_RWLOCK(fscache_object_list_lock);
22
23 struct fscache_objlist_data {
24 unsigned long config; /* display configuration */
25 #define FSCACHE_OBJLIST_CONFIG_KEY 0x00000001 /* show object keys */
26 #define FSCACHE_OBJLIST_CONFIG_AUX 0x00000002 /* show object auxdata */
27 #define FSCACHE_OBJLIST_CONFIG_COOKIE 0x00000004 /* show objects with cookies */
28 #define FSCACHE_OBJLIST_CONFIG_NOCOOKIE 0x00000008 /* show objects without cookies */
29 #define FSCACHE_OBJLIST_CONFIG_BUSY 0x00000010 /* show busy objects */
30 #define FSCACHE_OBJLIST_CONFIG_IDLE 0x00000020 /* show idle objects */
31 #define FSCACHE_OBJLIST_CONFIG_PENDWR 0x00000040 /* show objects with pending writes */
32 #define FSCACHE_OBJLIST_CONFIG_NOPENDWR 0x00000080 /* show objects without pending writes */
33 #define FSCACHE_OBJLIST_CONFIG_READS 0x00000100 /* show objects with active reads */
34 #define FSCACHE_OBJLIST_CONFIG_NOREADS 0x00000200 /* show objects without active reads */
35 #define FSCACHE_OBJLIST_CONFIG_EVENTS 0x00000400 /* show objects with events */
36 #define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800 /* show objects without no events */
37 #define FSCACHE_OBJLIST_CONFIG_WORK 0x00001000 /* show objects with work */
38 #define FSCACHE_OBJLIST_CONFIG_NOWORK 0x00002000 /* show objects without work */
39
40 u8 buf[512]; /* key and aux data buffer */
41 };
42
43 /*
44 * Add an object to the object list
45 * - we use the address of the fscache_object structure as the key into the
46 * tree
47 */
48 void fscache_objlist_add(struct fscache_object *obj)
49 {
50 struct fscache_object *xobj;
51 struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
52
53 write_lock(&fscache_object_list_lock);
54
55 while (*p) {
56 parent = *p;
57 xobj = rb_entry(parent, struct fscache_object, objlist_link);
58
59 if (obj < xobj)
60 p = &(*p)->rb_left;
61 else if (obj > xobj)
62 p = &(*p)->rb_right;
63 else
64 BUG();
65 }
66
67 rb_link_node(&obj->objlist_link, parent, p);
68 rb_insert_color(&obj->objlist_link, &fscache_object_list);
69
70 write_unlock(&fscache_object_list_lock);
71 }
72
73 /**
74 * fscache_object_destroy - Note that a cache object is about to be destroyed
75 * @object: The object to be destroyed
76 *
77 * Note the imminent destruction and deallocation of a cache object record.
78 */
79 void fscache_object_destroy(struct fscache_object *obj)
80 {
81 write_lock(&fscache_object_list_lock);
82
83 BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
84 rb_erase(&obj->objlist_link, &fscache_object_list);
85
86 write_unlock(&fscache_object_list_lock);
87 }
88 EXPORT_SYMBOL(fscache_object_destroy);
89
90 /*
91 * find the object in the tree on or after the specified index
92 */
93 static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
94 {
95 struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
96 struct rb_node *p;
97 unsigned long pos;
98
99 if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
100 return NULL;
101 pos = *_pos;
102
103 /* banners (can't represent line 0 by pos 0 as that would involve
104 * returning a NULL pointer) */
105 if (pos == 0)
106 return (struct fscache_object *)(long)++(*_pos);
107 if (pos < 3)
108 return (struct fscache_object *)pos;
109
110 pobj = (struct fscache_object *)pos;
111 p = fscache_object_list.rb_node;
112 while (p) {
113 obj = rb_entry(p, struct fscache_object, objlist_link);
114 if (pobj < obj) {
115 if (!minobj || minobj > obj)
116 minobj = obj;
117 p = p->rb_left;
118 } else if (pobj > obj) {
119 p = p->rb_right;
120 } else {
121 minobj = obj;
122 break;
123 }
124 obj = NULL;
125 }
126
127 if (!minobj)
128 *_pos = (unsigned long) ERR_PTR(-ENOENT);
129 else if (minobj != obj)
130 *_pos = (unsigned long) minobj;
131 return minobj;
132 }
133
134 /*
135 * set up the iterator to start reading from the first line
136 */
137 static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
138 __acquires(&fscache_object_list_lock)
139 {
140 read_lock(&fscache_object_list_lock);
141 return fscache_objlist_lookup(_pos);
142 }
143
144 /*
145 * move to the next line
146 */
147 static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
148 {
149 (*_pos)++;
150 return fscache_objlist_lookup(_pos);
151 }
152
153 /*
154 * clean up after reading
155 */
156 static void fscache_objlist_stop(struct seq_file *m, void *v)
157 __releases(&fscache_object_list_lock)
158 {
159 read_unlock(&fscache_object_list_lock);
160 }
161
162 /*
163 * display an object
164 */
165 static int fscache_objlist_show(struct seq_file *m, void *v)
166 {
167 struct fscache_objlist_data *data = m->private;
168 struct fscache_object *obj = v;
169 unsigned long config = data->config;
170 uint16_t keylen, auxlen;
171 char _type[3], *type;
172 bool no_cookie;
173 u8 *buf = data->buf, *p;
174
175 if ((unsigned long) v == 1) {
176 seq_puts(m, "OBJECT PARENT STAT CHLDN OPS OOP IPR EX READS"
177 " EM EV F S"
178 " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
179 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
180 FSCACHE_OBJLIST_CONFIG_AUX))
181 seq_puts(m, " ");
182 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
183 seq_puts(m, "OBJECT_KEY");
184 if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
185 FSCACHE_OBJLIST_CONFIG_AUX)) ==
186 (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
187 seq_puts(m, ", ");
188 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
189 seq_puts(m, "AUX_DATA");
190 seq_puts(m, "\n");
191 return 0;
192 }
193
194 if ((unsigned long) v == 2) {
195 seq_puts(m, "======== ======== ==== ===== === === === == ====="
196 " == == = ="
197 " | ================ == == ================");
198 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
199 FSCACHE_OBJLIST_CONFIG_AUX))
200 seq_puts(m, " ================");
201 seq_puts(m, "\n");
202 return 0;
203 }
204
205 /* filter out any unwanted objects */
206 #define FILTER(criterion, _yes, _no) \
207 do { \
208 unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes; \
209 unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no; \
210 if (criterion) { \
211 if (!(config & yes)) \
212 return 0; \
213 } else { \
214 if (!(config & no)) \
215 return 0; \
216 } \
217 } while(0)
218
219 if (~config) {
220 FILTER(obj->cookie,
221 COOKIE, NOCOOKIE);
222 FILTER(obj->state != FSCACHE_OBJECT_ACTIVE ||
223 obj->n_ops != 0 ||
224 obj->n_obj_ops != 0 ||
225 obj->flags ||
226 !list_empty(&obj->dependents),
227 BUSY, IDLE);
228 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
229 PENDWR, NOPENDWR);
230 FILTER(atomic_read(&obj->n_reads),
231 READS, NOREADS);
232 FILTER(obj->events & obj->event_mask,
233 EVENTS, NOEVENTS);
234 FILTER(work_busy(&obj->work), WORK, NOWORK);
235 }
236
237 seq_printf(m,
238 "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1x | ",
239 obj->debug_id,
240 obj->parent ? obj->parent->debug_id : -1,
241 fscache_object_states_short[obj->state],
242 obj->n_children,
243 obj->n_ops,
244 obj->n_obj_ops,
245 obj->n_in_progress,
246 obj->n_exclusive,
247 atomic_read(&obj->n_reads),
248 obj->event_mask,
249 obj->events,
250 obj->flags,
251 work_busy(&obj->work));
252
253 no_cookie = true;
254 keylen = auxlen = 0;
255 if (obj->cookie) {
256 spin_lock(&obj->lock);
257 if (obj->cookie) {
258 switch (obj->cookie->def->type) {
259 case 0:
260 type = "IX";
261 break;
262 case 1:
263 type = "DT";
264 break;
265 default:
266 sprintf(_type, "%02u",
267 obj->cookie->def->type);
268 type = _type;
269 break;
270 }
271
272 seq_printf(m, "%-16s %s %2lx %16p",
273 obj->cookie->def->name,
274 type,
275 obj->cookie->flags,
276 obj->cookie->netfs_data);
277
278 if (obj->cookie->def->get_key &&
279 config & FSCACHE_OBJLIST_CONFIG_KEY)
280 keylen = obj->cookie->def->get_key(
281 obj->cookie->netfs_data,
282 buf, 400);
283
284 if (obj->cookie->def->get_aux &&
285 config & FSCACHE_OBJLIST_CONFIG_AUX)
286 auxlen = obj->cookie->def->get_aux(
287 obj->cookie->netfs_data,
288 buf + keylen, 512 - keylen);
289
290 no_cookie = false;
291 }
292 spin_unlock(&obj->lock);
293
294 if (!no_cookie && (keylen > 0 || auxlen > 0)) {
295 seq_printf(m, " ");
296 for (p = buf; keylen > 0; keylen--)
297 seq_printf(m, "%02x", *p++);
298 if (auxlen > 0) {
299 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
300 seq_printf(m, ", ");
301 for (; auxlen > 0; auxlen--)
302 seq_printf(m, "%02x", *p++);
303 }
304 }
305 }
306
307 if (no_cookie)
308 seq_printf(m, "<no_cookie>\n");
309 else
310 seq_printf(m, "\n");
311 return 0;
312 }
313
314 static const struct seq_operations fscache_objlist_ops = {
315 .start = fscache_objlist_start,
316 .stop = fscache_objlist_stop,
317 .next = fscache_objlist_next,
318 .show = fscache_objlist_show,
319 };
320
321 /*
322 * get the configuration for filtering the list
323 */
324 static void fscache_objlist_config(struct fscache_objlist_data *data)
325 {
326 #ifdef CONFIG_KEYS
327 struct user_key_payload *confkey;
328 unsigned long config;
329 struct key *key;
330 const char *buf;
331 int len;
332
333 key = request_key(&key_type_user, "fscache:objlist", NULL);
334 if (IS_ERR(key))
335 goto no_config;
336
337 config = 0;
338 rcu_read_lock();
339
340 confkey = key->payload.data;
341 if (!confkey) {
342 /* key was revoked */
343 rcu_read_unlock();
344 key_put(key);
345 goto no_config;
346 }
347
348 buf = confkey->data;
349
350 for (len = confkey->datalen - 1; len >= 0; len--) {
351 switch (buf[len]) {
352 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY; break;
353 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX; break;
354 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE; break;
355 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE; break;
356 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY; break;
357 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE; break;
358 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR; break;
359 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR; break;
360 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS; break;
361 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS; break;
362 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK; break;
363 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK; break;
364 }
365 }
366
367 rcu_read_unlock();
368 key_put(key);
369
370 if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
371 config |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
372 if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
373 config |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
374 if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
375 config |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
376 if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
377 config |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
378 if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
379 config |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
380 if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
381 config |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
382
383 data->config = config;
384 return;
385
386 no_config:
387 #endif
388 data->config = ULONG_MAX;
389 }
390
391 /*
392 * open "/proc/fs/fscache/objects" to provide a list of active objects
393 * - can be configured by a user-defined key added to the caller's keyrings
394 */
395 static int fscache_objlist_open(struct inode *inode, struct file *file)
396 {
397 struct fscache_objlist_data *data;
398 struct seq_file *m;
399 int ret;
400
401 ret = seq_open(file, &fscache_objlist_ops);
402 if (ret < 0)
403 return ret;
404
405 m = file->private_data;
406
407 /* buffer for key extraction */
408 data = kmalloc(sizeof(struct fscache_objlist_data), GFP_KERNEL);
409 if (!data) {
410 seq_release(inode, file);
411 return -ENOMEM;
412 }
413
414 /* get the configuration key */
415 fscache_objlist_config(data);
416
417 m->private = data;
418 return 0;
419 }
420
421 /*
422 * clean up on close
423 */
424 static int fscache_objlist_release(struct inode *inode, struct file *file)
425 {
426 struct seq_file *m = file->private_data;
427
428 kfree(m->private);
429 m->private = NULL;
430 return seq_release(inode, file);
431 }
432
433 const struct file_operations fscache_objlist_fops = {
434 .owner = THIS_MODULE,
435 .open = fscache_objlist_open,
436 .read = seq_read,
437 .llseek = seq_lseek,
438 .release = fscache_objlist_release,
439 };
440
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