tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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
20static struct rb_root fscache_object_list;
21static DEFINE_RWLOCK(fscache_object_list_lock);
22
23struct 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
41/*
42 * Add an object to the object list
43 * - we use the address of the fscache_object structure as the key into the
44 * tree
45 */
46void fscache_objlist_add(struct fscache_object *obj)
47{
48 struct fscache_object *xobj;
49 struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
50
51 ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
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 * Remove an object from the object list.
75 */
76void fscache_objlist_remove(struct fscache_object *obj)
77{
78 if (RB_EMPTY_NODE(&obj->objlist_link))
79 return;
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
89/*
90 * find the object in the tree on or after the specified index
91 */
92static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
93{
94 struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
95 struct rb_node *p;
96 unsigned long pos;
97
98 if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
99 return NULL;
100 pos = *_pos;
101
102 /* banners (can't represent line 0 by pos 0 as that would involve
103 * returning a NULL pointer) */
104 if (pos == 0)
105 return (struct fscache_object *)(long)++(*_pos);
106 if (pos < 3)
107 return (struct fscache_object *)pos;
108
109 pobj = (struct fscache_object *)pos;
110 p = fscache_object_list.rb_node;
111 while (p) {
112 obj = rb_entry(p, struct fscache_object, objlist_link);
113 if (pobj < obj) {
114 if (!minobj || minobj > obj)
115 minobj = obj;
116 p = p->rb_left;
117 } else if (pobj > obj) {
118 p = p->rb_right;
119 } else {
120 minobj = obj;
121 break;
122 }
123 obj = NULL;
124 }
125
126 if (!minobj)
127 *_pos = (unsigned long) ERR_PTR(-ENOENT);
128 else if (minobj != obj)
129 *_pos = (unsigned long) minobj;
130 return minobj;
131}
132
133/*
134 * set up the iterator to start reading from the first line
135 */
136static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
137 __acquires(&fscache_object_list_lock)
138{
139 read_lock(&fscache_object_list_lock);
140 return fscache_objlist_lookup(_pos);
141}
142
143/*
144 * move to the next line
145 */
146static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
147{
148 (*_pos)++;
149 return fscache_objlist_lookup(_pos);
150}
151
152/*
153 * clean up after reading
154 */
155static void fscache_objlist_stop(struct seq_file *m, void *v)
156 __releases(&fscache_object_list_lock)
157{
158 read_unlock(&fscache_object_list_lock);
159}
160
161/*
162 * display an object
163 */
164static int fscache_objlist_show(struct seq_file *m, void *v)
165{
166 struct fscache_objlist_data *data = m->private;
167 struct fscache_object *obj = v;
168 struct fscache_cookie *cookie;
169 unsigned long config = data->config;
170 char _type[3], *type;
171 u8 *p;
172
173 if ((unsigned long) v == 1) {
174 seq_puts(m, "OBJECT PARENT STAT CHLDN OPS OOP IPR EX READS"
175 " EM EV FL S"
176 " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
177 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
178 FSCACHE_OBJLIST_CONFIG_AUX))
179 seq_puts(m, " ");
180 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
181 seq_puts(m, "OBJECT_KEY");
182 if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
183 FSCACHE_OBJLIST_CONFIG_AUX)) ==
184 (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
185 seq_puts(m, ", ");
186 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
187 seq_puts(m, "AUX_DATA");
188 seq_puts(m, "\n");
189 return 0;
190 }
191
192 if ((unsigned long) v == 2) {
193 seq_puts(m, "======== ======== ==== ===== === === === == ====="
194 " == == == ="
195 " | ================ == == ================");
196 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
197 FSCACHE_OBJLIST_CONFIG_AUX))
198 seq_puts(m, " ================");
199 seq_puts(m, "\n");
200 return 0;
201 }
202
203 /* filter out any unwanted objects */
204#define FILTER(criterion, _yes, _no) \
205 do { \
206 unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes; \
207 unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no; \
208 if (criterion) { \
209 if (!(config & yes)) \
210 return 0; \
211 } else { \
212 if (!(config & no)) \
213 return 0; \
214 } \
215 } while(0)
216
217 cookie = obj->cookie;
218 if (~config) {
219 FILTER(cookie->def,
220 COOKIE, NOCOOKIE);
221 FILTER(fscache_object_is_active(obj) ||
222 obj->n_ops != 0 ||
223 obj->n_obj_ops != 0 ||
224 obj->flags ||
225 !list_empty(&obj->dependents),
226 BUSY, IDLE);
227 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
228 PENDWR, NOPENDWR);
229 FILTER(atomic_read(&obj->n_reads),
230 READS, NOREADS);
231 FILTER(obj->events & obj->event_mask,
232 EVENTS, NOEVENTS);
233 FILTER(work_busy(&obj->work), WORK, NOWORK);
234 }
235
236 seq_printf(m,
237 "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
238 obj->debug_id,
239 obj->parent ? obj->parent->debug_id : -1,
240 obj->state->short_name,
241 obj->n_children,
242 obj->n_ops,
243 obj->n_obj_ops,
244 obj->n_in_progress,
245 obj->n_exclusive,
246 atomic_read(&obj->n_reads),
247 obj->event_mask,
248 obj->events,
249 obj->flags,
250 work_busy(&obj->work));
251
252 if (fscache_use_cookie(obj)) {
253 uint16_t keylen = 0, auxlen = 0;
254
255 switch (cookie->type) {
256 case 0:
257 type = "IX";
258 break;
259 case 1:
260 type = "DT";
261 break;
262 default:
263 snprintf(_type, sizeof(_type), "%02u",
264 cookie->type);
265 type = _type;
266 break;
267 }
268
269 seq_printf(m, "%-16s %s %2lx %16p",
270 cookie->def->name,
271 type,
272 cookie->flags,
273 cookie->netfs_data);
274
275 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
276 keylen = cookie->key_len;
277
278 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
279 auxlen = cookie->aux_len;
280
281 if (keylen > 0 || auxlen > 0) {
282 seq_puts(m, " ");
283 p = keylen <= sizeof(cookie->inline_key) ?
284 cookie->inline_key : cookie->key;
285 for (; keylen > 0; keylen--)
286 seq_printf(m, "%02x", *p++);
287 if (auxlen > 0) {
288 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
289 seq_puts(m, ", ");
290 p = auxlen <= sizeof(cookie->inline_aux) ?
291 cookie->inline_aux : cookie->aux;
292 for (; auxlen > 0; auxlen--)
293 seq_printf(m, "%02x", *p++);
294 }
295 }
296
297 seq_puts(m, "\n");
298 fscache_unuse_cookie(obj);
299 } else {
300 seq_puts(m, "<no_netfs>\n");
301 }
302 return 0;
303}
304
305static const struct seq_operations fscache_objlist_ops = {
306 .start = fscache_objlist_start,
307 .stop = fscache_objlist_stop,
308 .next = fscache_objlist_next,
309 .show = fscache_objlist_show,
310};
311
312/*
313 * get the configuration for filtering the list
314 */
315static void fscache_objlist_config(struct fscache_objlist_data *data)
316{
317#ifdef CONFIG_KEYS
318 const struct user_key_payload *confkey;
319 unsigned long config;
320 struct key *key;
321 const char *buf;
322 int len;
323
324 key = request_key(&key_type_user, "fscache:objlist", NULL);
325 if (IS_ERR(key))
326 goto no_config;
327
328 config = 0;
329 rcu_read_lock();
330
331 confkey = user_key_payload_rcu(key);
332 if (!confkey) {
333 /* key was revoked */
334 rcu_read_unlock();
335 key_put(key);
336 goto no_config;
337 }
338
339 buf = confkey->data;
340
341 for (len = confkey->datalen - 1; len >= 0; len--) {
342 switch (buf[len]) {
343 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY; break;
344 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX; break;
345 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE; break;
346 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE; break;
347 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY; break;
348 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE; break;
349 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR; break;
350 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR; break;
351 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS; break;
352 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS; break;
353 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK; break;
354 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK; break;
355 }
356 }
357
358 rcu_read_unlock();
359 key_put(key);
360
361 if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
362 config |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
363 if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
364 config |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
365 if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
366 config |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
367 if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
368 config |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
369 if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
370 config |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
371 if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
372 config |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
373
374 data->config = config;
375 return;
376
377no_config:
378#endif
379 data->config = ULONG_MAX;
380}
381
382/*
383 * open "/proc/fs/fscache/objects" to provide a list of active objects
384 * - can be configured by a user-defined key added to the caller's keyrings
385 */
386static int fscache_objlist_open(struct inode *inode, struct file *file)
387{
388 struct fscache_objlist_data *data;
389
390 data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
391 if (!data)
392 return -ENOMEM;
393
394 /* get the configuration key */
395 fscache_objlist_config(data);
396
397 return 0;
398}
399
400/*
401 * clean up on close
402 */
403static int fscache_objlist_release(struct inode *inode, struct file *file)
404{
405 struct seq_file *m = file->private_data;
406
407 kfree(m->private);
408 m->private = NULL;
409 return seq_release(inode, file);
410}
411
412const struct file_operations fscache_objlist_fops = {
413 .open = fscache_objlist_open,
414 .read = seq_read,
415 .llseek = seq_lseek,
416 .release = fscache_objlist_release,
417};