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object-list.c
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1 /* Global fscache object list maintainer and viewer
2  *
3  * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells ([email protected])
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 
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 & FSCACHE_OBJECT_EVENTS_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  buf = confkey->data;
342 
343  for (len = confkey->datalen - 1; len >= 0; len--) {
344  switch (buf[len]) {
345  case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY; break;
346  case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX; break;
347  case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE; break;
348  case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE; break;
349  case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY; break;
350  case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE; break;
351  case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR; break;
352  case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR; break;
353  case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS; break;
354  case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS; break;
355  case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK; break;
356  case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK; break;
357  }
358  }
359 
360  rcu_read_unlock();
361  key_put(key);
362 
363  if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
364  config |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
365  if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
366  config |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
367  if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
368  config |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
369  if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
370  config |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
371  if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
372  config |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
373  if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
374  config |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
375 
376  data->config = config;
377  return;
378 
379 no_config:
380 #endif
381  data->config = ULONG_MAX;
382 }
383 
384 /*
385  * open "/proc/fs/fscache/objects" to provide a list of active objects
386  * - can be configured by a user-defined key added to the caller's keyrings
387  */
388 static int fscache_objlist_open(struct inode *inode, struct file *file)
389 {
390  struct fscache_objlist_data *data;
391  struct seq_file *m;
392  int ret;
393 
394  ret = seq_open(file, &fscache_objlist_ops);
395  if (ret < 0)
396  return ret;
397 
398  m = file->private_data;
399 
400  /* buffer for key extraction */
401  data = kmalloc(sizeof(struct fscache_objlist_data), GFP_KERNEL);
402  if (!data) {
403  seq_release(inode, file);
404  return -ENOMEM;
405  }
406 
407  /* get the configuration key */
408  fscache_objlist_config(data);
409 
410  m->private = data;
411  return 0;
412 }
413 
414 /*
415  * clean up on close
416  */
417 static int fscache_objlist_release(struct inode *inode, struct file *file)
418 {
419  struct seq_file *m = file->private_data;
420 
421  kfree(m->private);
422  m->private = NULL;
423  return seq_release(inode, file);
424 }
425 
426 const struct file_operations fscache_objlist_fops = {
427  .owner = THIS_MODULE,
428  .open = fscache_objlist_open,
429  .read = seq_read,
430  .llseek = seq_lseek,
431  .release = fscache_objlist_release,
432 };
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