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 */
fscache_objlist_add(struct fscache_object * obj)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 ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
54
55 write_lock(&fscache_object_list_lock);
56
57 while (*p) {
58 parent = *p;
59 xobj = rb_entry(parent, struct fscache_object, objlist_link);
60
61 if (obj < xobj)
62 p = &(*p)->rb_left;
63 else if (obj > xobj)
64 p = &(*p)->rb_right;
65 else
66 BUG();
67 }
68
69 rb_link_node(&obj->objlist_link, parent, p);
70 rb_insert_color(&obj->objlist_link, &fscache_object_list);
71
72 write_unlock(&fscache_object_list_lock);
73 }
74
75 /*
76 * Remove an object from the object list.
77 */
fscache_objlist_remove(struct fscache_object * obj)78 void fscache_objlist_remove(struct fscache_object *obj)
79 {
80 if (RB_EMPTY_NODE(&obj->objlist_link))
81 return;
82
83 write_lock(&fscache_object_list_lock);
84
85 BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
86 rb_erase(&obj->objlist_link, &fscache_object_list);
87
88 write_unlock(&fscache_object_list_lock);
89 }
90
91 /*
92 * find the object in the tree on or after the specified index
93 */
fscache_objlist_lookup(loff_t * _pos)94 static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
95 {
96 struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
97 struct rb_node *p;
98 unsigned long pos;
99
100 if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
101 return NULL;
102 pos = *_pos;
103
104 /* banners (can't represent line 0 by pos 0 as that would involve
105 * returning a NULL pointer) */
106 if (pos == 0)
107 return (struct fscache_object *)(long)++(*_pos);
108 if (pos < 3)
109 return (struct fscache_object *)pos;
110
111 pobj = (struct fscache_object *)pos;
112 p = fscache_object_list.rb_node;
113 while (p) {
114 obj = rb_entry(p, struct fscache_object, objlist_link);
115 if (pobj < obj) {
116 if (!minobj || minobj > obj)
117 minobj = obj;
118 p = p->rb_left;
119 } else if (pobj > obj) {
120 p = p->rb_right;
121 } else {
122 minobj = obj;
123 break;
124 }
125 obj = NULL;
126 }
127
128 if (!minobj)
129 *_pos = (unsigned long) ERR_PTR(-ENOENT);
130 else if (minobj != obj)
131 *_pos = (unsigned long) minobj;
132 return minobj;
133 }
134
135 /*
136 * set up the iterator to start reading from the first line
137 */
fscache_objlist_start(struct seq_file * m,loff_t * _pos)138 static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
139 __acquires(&fscache_object_list_lock)
140 {
141 read_lock(&fscache_object_list_lock);
142 return fscache_objlist_lookup(_pos);
143 }
144
145 /*
146 * move to the next line
147 */
fscache_objlist_next(struct seq_file * m,void * v,loff_t * _pos)148 static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
149 {
150 (*_pos)++;
151 return fscache_objlist_lookup(_pos);
152 }
153
154 /*
155 * clean up after reading
156 */
fscache_objlist_stop(struct seq_file * m,void * v)157 static void fscache_objlist_stop(struct seq_file *m, void *v)
158 __releases(&fscache_object_list_lock)
159 {
160 read_unlock(&fscache_object_list_lock);
161 }
162
163 /*
164 * display an object
165 */
fscache_objlist_show(struct seq_file * m,void * v)166 static int fscache_objlist_show(struct seq_file *m, void *v)
167 {
168 struct fscache_objlist_data *data = m->private;
169 struct fscache_object *obj = v;
170 struct fscache_cookie *cookie;
171 unsigned long config = data->config;
172 char _type[3], *type;
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 FL 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 cookie = obj->cookie;
220 if (~config) {
221 FILTER(cookie->def,
222 COOKIE, NOCOOKIE);
223 FILTER(fscache_object_is_active(obj) ||
224 obj->n_ops != 0 ||
225 obj->n_obj_ops != 0 ||
226 obj->flags ||
227 !list_empty(&obj->dependents),
228 BUSY, IDLE);
229 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
230 PENDWR, NOPENDWR);
231 FILTER(atomic_read(&obj->n_reads),
232 READS, NOREADS);
233 FILTER(obj->events & obj->event_mask,
234 EVENTS, NOEVENTS);
235 FILTER(work_busy(&obj->work), WORK, NOWORK);
236 }
237
238 seq_printf(m,
239 "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
240 obj->debug_id,
241 obj->parent ? obj->parent->debug_id : -1,
242 obj->state->short_name,
243 obj->n_children,
244 obj->n_ops,
245 obj->n_obj_ops,
246 obj->n_in_progress,
247 obj->n_exclusive,
248 atomic_read(&obj->n_reads),
249 obj->event_mask,
250 obj->events,
251 obj->flags,
252 work_busy(&obj->work));
253
254 if (fscache_use_cookie(obj)) {
255 uint16_t keylen = 0, auxlen = 0;
256
257 switch (cookie->def->type) {
258 case 0:
259 type = "IX";
260 break;
261 case 1:
262 type = "DT";
263 break;
264 default:
265 sprintf(_type, "%02u", cookie->def->type);
266 type = _type;
267 break;
268 }
269
270 seq_printf(m, "%-16s %s %2lx %16p",
271 cookie->def->name,
272 type,
273 cookie->flags,
274 cookie->netfs_data);
275
276 if (cookie->def->get_key &&
277 config & FSCACHE_OBJLIST_CONFIG_KEY)
278 keylen = cookie->def->get_key(cookie->netfs_data,
279 buf, 400);
280
281 if (cookie->def->get_aux &&
282 config & FSCACHE_OBJLIST_CONFIG_AUX)
283 auxlen = cookie->def->get_aux(cookie->netfs_data,
284 buf + keylen, 512 - keylen);
285 fscache_unuse_cookie(obj);
286
287 if (keylen > 0 || auxlen > 0) {
288 seq_puts(m, " ");
289 for (p = buf; keylen > 0; keylen--)
290 seq_printf(m, "%02x", *p++);
291 if (auxlen > 0) {
292 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
293 seq_puts(m, ", ");
294 for (; auxlen > 0; auxlen--)
295 seq_printf(m, "%02x", *p++);
296 }
297 }
298
299 seq_puts(m, "\n");
300 } else {
301 seq_puts(m, "<no_netfs>\n");
302 }
303 return 0;
304 }
305
306 static const struct seq_operations fscache_objlist_ops = {
307 .start = fscache_objlist_start,
308 .stop = fscache_objlist_stop,
309 .next = fscache_objlist_next,
310 .show = fscache_objlist_show,
311 };
312
313 /*
314 * get the configuration for filtering the list
315 */
fscache_objlist_config(struct fscache_objlist_data * data)316 static void fscache_objlist_config(struct fscache_objlist_data *data)
317 {
318 #ifdef CONFIG_KEYS
319 const struct user_key_payload *confkey;
320 unsigned long config;
321 struct key *key;
322 const char *buf;
323 int len;
324
325 key = request_key(&key_type_user, "fscache:objlist", NULL);
326 if (IS_ERR(key))
327 goto no_config;
328
329 config = 0;
330 rcu_read_lock();
331
332 confkey = user_key_payload_rcu(key);
333 if (!confkey) {
334 /* key was revoked */
335 rcu_read_unlock();
336 key_put(key);
337 goto no_config;
338 }
339
340 buf = confkey->data;
341
342 for (len = confkey->datalen - 1; len >= 0; len--) {
343 switch (buf[len]) {
344 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY; break;
345 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX; break;
346 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE; break;
347 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE; break;
348 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY; break;
349 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE; break;
350 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR; break;
351 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR; break;
352 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS; break;
353 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS; break;
354 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK; break;
355 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK; break;
356 }
357 }
358
359 rcu_read_unlock();
360 key_put(key);
361
362 if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
363 config |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
364 if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
365 config |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
366 if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
367 config |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
368 if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
369 config |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
370 if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
371 config |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
372 if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
373 config |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
374
375 data->config = config;
376 return;
377
378 no_config:
379 #endif
380 data->config = ULONG_MAX;
381 }
382
383 /*
384 * open "/proc/fs/fscache/objects" to provide a list of active objects
385 * - can be configured by a user-defined key added to the caller's keyrings
386 */
fscache_objlist_open(struct inode * inode,struct file * file)387 static int fscache_objlist_open(struct inode *inode, struct file *file)
388 {
389 struct fscache_objlist_data *data;
390
391 data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
392 if (!data)
393 return -ENOMEM;
394
395 /* get the configuration key */
396 fscache_objlist_config(data);
397
398 return 0;
399 }
400
401 /*
402 * clean up on close
403 */
fscache_objlist_release(struct inode * inode,struct file * file)404 static int fscache_objlist_release(struct inode *inode, struct file *file)
405 {
406 struct seq_file *m = file->private_data;
407
408 kfree(m->private);
409 m->private = NULL;
410 return seq_release(inode, file);
411 }
412
413 const struct file_operations fscache_objlist_fops = {
414 .open = fscache_objlist_open,
415 .read = seq_read,
416 .llseek = seq_lseek,
417 .release = fscache_objlist_release,
418 };
419