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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Global fscache object list maintainer and viewer
3 *
4 * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define FSCACHE_DEBUG_LEVEL COOKIE
9#include <linux/module.h>
10#include <linux/seq_file.h>
11#include <linux/slab.h>
12#include <linux/key.h>
13#include <keys/user-type.h>
14#include "internal.h"
15
16static struct rb_root fscache_object_list;
17static DEFINE_RWLOCK(fscache_object_list_lock);
18
19struct fscache_objlist_data {
20 unsigned long config; /* display configuration */
21#define FSCACHE_OBJLIST_CONFIG_KEY 0x00000001 /* show object keys */
22#define FSCACHE_OBJLIST_CONFIG_AUX 0x00000002 /* show object auxdata */
23#define FSCACHE_OBJLIST_CONFIG_COOKIE 0x00000004 /* show objects with cookies */
24#define FSCACHE_OBJLIST_CONFIG_NOCOOKIE 0x00000008 /* show objects without cookies */
25#define FSCACHE_OBJLIST_CONFIG_BUSY 0x00000010 /* show busy objects */
26#define FSCACHE_OBJLIST_CONFIG_IDLE 0x00000020 /* show idle objects */
27#define FSCACHE_OBJLIST_CONFIG_PENDWR 0x00000040 /* show objects with pending writes */
28#define FSCACHE_OBJLIST_CONFIG_NOPENDWR 0x00000080 /* show objects without pending writes */
29#define FSCACHE_OBJLIST_CONFIG_READS 0x00000100 /* show objects with active reads */
30#define FSCACHE_OBJLIST_CONFIG_NOREADS 0x00000200 /* show objects without active reads */
31#define FSCACHE_OBJLIST_CONFIG_EVENTS 0x00000400 /* show objects with events */
32#define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800 /* show objects without no events */
33#define FSCACHE_OBJLIST_CONFIG_WORK 0x00001000 /* show objects with work */
34#define FSCACHE_OBJLIST_CONFIG_NOWORK 0x00002000 /* show objects without work */
35};
36
37/*
38 * Add an object to the object list
39 * - we use the address of the fscache_object structure as the key into the
40 * tree
41 */
42void fscache_objlist_add(struct fscache_object *obj)
43{
44 struct fscache_object *xobj;
45 struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
46
47 ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
48
49 write_lock(&fscache_object_list_lock);
50
51 while (*p) {
52 parent = *p;
53 xobj = rb_entry(parent, struct fscache_object, objlist_link);
54
55 if (obj < xobj)
56 p = &(*p)->rb_left;
57 else if (obj > xobj)
58 p = &(*p)->rb_right;
59 else
60 BUG();
61 }
62
63 rb_link_node(&obj->objlist_link, parent, p);
64 rb_insert_color(&obj->objlist_link, &fscache_object_list);
65
66 write_unlock(&fscache_object_list_lock);
67}
68
69/*
70 * Remove an object from the object list.
71 */
72void fscache_objlist_remove(struct fscache_object *obj)
73{
74 if (RB_EMPTY_NODE(&obj->objlist_link))
75 return;
76
77 write_lock(&fscache_object_list_lock);
78
79 BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
80 rb_erase(&obj->objlist_link, &fscache_object_list);
81
82 write_unlock(&fscache_object_list_lock);
83}
84
85/*
86 * find the object in the tree on or after the specified index
87 */
88static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
89{
90 struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
91 struct rb_node *p;
92 unsigned long pos;
93
94 if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
95 return NULL;
96 pos = *_pos;
97
98 /* banners (can't represent line 0 by pos 0 as that would involve
99 * returning a NULL pointer) */
100 if (pos == 0)
101 return (struct fscache_object *)(long)++(*_pos);
102 if (pos < 3)
103 return (struct fscache_object *)pos;
104
105 pobj = (struct fscache_object *)pos;
106 p = fscache_object_list.rb_node;
107 while (p) {
108 obj = rb_entry(p, struct fscache_object, objlist_link);
109 if (pobj < obj) {
110 if (!minobj || minobj > obj)
111 minobj = obj;
112 p = p->rb_left;
113 } else if (pobj > obj) {
114 p = p->rb_right;
115 } else {
116 minobj = obj;
117 break;
118 }
119 obj = NULL;
120 }
121
122 if (!minobj)
123 *_pos = (unsigned long) ERR_PTR(-ENOENT);
124 else if (minobj != obj)
125 *_pos = (unsigned long) minobj;
126 return minobj;
127}
128
129/*
130 * set up the iterator to start reading from the first line
131 */
132static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
133 __acquires(&fscache_object_list_lock)
134{
135 read_lock(&fscache_object_list_lock);
136 return fscache_objlist_lookup(_pos);
137}
138
139/*
140 * move to the next line
141 */
142static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
143{
144 (*_pos)++;
145 return fscache_objlist_lookup(_pos);
146}
147
148/*
149 * clean up after reading
150 */
151static void fscache_objlist_stop(struct seq_file *m, void *v)
152 __releases(&fscache_object_list_lock)
153{
154 read_unlock(&fscache_object_list_lock);
155}
156
157/*
158 * display an object
159 */
160static int fscache_objlist_show(struct seq_file *m, void *v)
161{
162 struct fscache_objlist_data *data = m->private;
163 struct fscache_object *obj = v;
164 struct fscache_cookie *cookie;
165 unsigned long config = data->config;
166 char _type[3], *type;
167 u8 *p;
168
169 if ((unsigned long) v == 1) {
170 seq_puts(m, "OBJECT PARENT STAT CHLDN OPS OOP IPR EX READS"
171 " EM EV FL S"
172 " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
173 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
174 FSCACHE_OBJLIST_CONFIG_AUX))
175 seq_puts(m, " ");
176 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
177 seq_puts(m, "OBJECT_KEY");
178 if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
179 FSCACHE_OBJLIST_CONFIG_AUX)) ==
180 (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
181 seq_puts(m, ", ");
182 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
183 seq_puts(m, "AUX_DATA");
184 seq_puts(m, "\n");
185 return 0;
186 }
187
188 if ((unsigned long) v == 2) {
189 seq_puts(m, "======== ======== ==== ===== === === === == ====="
190 " == == == ="
191 " | ================ == == ================");
192 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
193 FSCACHE_OBJLIST_CONFIG_AUX))
194 seq_puts(m, " ================");
195 seq_puts(m, "\n");
196 return 0;
197 }
198
199 /* filter out any unwanted objects */
200#define FILTER(criterion, _yes, _no) \
201 do { \
202 unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes; \
203 unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no; \
204 if (criterion) { \
205 if (!(config & yes)) \
206 return 0; \
207 } else { \
208 if (!(config & no)) \
209 return 0; \
210 } \
211 } while(0)
212
213 cookie = obj->cookie;
214 if (~config) {
215 FILTER(cookie->def,
216 COOKIE, NOCOOKIE);
217 FILTER(fscache_object_is_active(obj) ||
218 obj->n_ops != 0 ||
219 obj->n_obj_ops != 0 ||
220 obj->flags ||
221 !list_empty(&obj->dependents),
222 BUSY, IDLE);
223 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
224 PENDWR, NOPENDWR);
225 FILTER(atomic_read(&obj->n_reads),
226 READS, NOREADS);
227 FILTER(obj->events & obj->event_mask,
228 EVENTS, NOEVENTS);
229 FILTER(work_busy(&obj->work), WORK, NOWORK);
230 }
231
232 seq_printf(m,
233 "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
234 obj->debug_id,
235 obj->parent ? obj->parent->debug_id : -1,
236 obj->state->short_name,
237 obj->n_children,
238 obj->n_ops,
239 obj->n_obj_ops,
240 obj->n_in_progress,
241 obj->n_exclusive,
242 atomic_read(&obj->n_reads),
243 obj->event_mask,
244 obj->events,
245 obj->flags,
246 work_busy(&obj->work));
247
248 if (fscache_use_cookie(obj)) {
249 uint16_t keylen = 0, auxlen = 0;
250
251 switch (cookie->type) {
252 case 0:
253 type = "IX";
254 break;
255 case 1:
256 type = "DT";
257 break;
258 default:
259 snprintf(_type, sizeof(_type), "%02u",
260 cookie->type);
261 type = _type;
262 break;
263 }
264
265 seq_printf(m, "%-16s %s %2lx %16p",
266 cookie->def->name,
267 type,
268 cookie->flags,
269 cookie->netfs_data);
270
271 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
272 keylen = cookie->key_len;
273
274 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
275 auxlen = cookie->aux_len;
276
277 if (keylen > 0 || auxlen > 0) {
278 seq_puts(m, " ");
279 p = keylen <= sizeof(cookie->inline_key) ?
280 cookie->inline_key : cookie->key;
281 for (; keylen > 0; keylen--)
282 seq_printf(m, "%02x", *p++);
283 if (auxlen > 0) {
284 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
285 seq_puts(m, ", ");
286 p = auxlen <= sizeof(cookie->inline_aux) ?
287 cookie->inline_aux : cookie->aux;
288 for (; auxlen > 0; auxlen--)
289 seq_printf(m, "%02x", *p++);
290 }
291 }
292
293 seq_puts(m, "\n");
294 fscache_unuse_cookie(obj);
295 } else {
296 seq_puts(m, "<no_netfs>\n");
297 }
298 return 0;
299}
300
301static const struct seq_operations fscache_objlist_ops = {
302 .start = fscache_objlist_start,
303 .stop = fscache_objlist_stop,
304 .next = fscache_objlist_next,
305 .show = fscache_objlist_show,
306};
307
308/*
309 * get the configuration for filtering the list
310 */
311static void fscache_objlist_config(struct fscache_objlist_data *data)
312{
313#ifdef CONFIG_KEYS
314 const struct user_key_payload *confkey;
315 unsigned long config;
316 struct key *key;
317 const char *buf;
318 int len;
319
320 key = request_key(&key_type_user, "fscache:objlist", NULL);
321 if (IS_ERR(key))
322 goto no_config;
323
324 config = 0;
325 rcu_read_lock();
326
327 confkey = user_key_payload_rcu(key);
328 if (!confkey) {
329 /* key was revoked */
330 rcu_read_unlock();
331 key_put(key);
332 goto no_config;
333 }
334
335 buf = confkey->data;
336
337 for (len = confkey->datalen - 1; len >= 0; len--) {
338 switch (buf[len]) {
339 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY; break;
340 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX; break;
341 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE; break;
342 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE; break;
343 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY; break;
344 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE; break;
345 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR; break;
346 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR; break;
347 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS; break;
348 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS; break;
349 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK; break;
350 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK; break;
351 }
352 }
353
354 rcu_read_unlock();
355 key_put(key);
356
357 if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
358 config |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
359 if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
360 config |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
361 if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
362 config |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
363 if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
364 config |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
365 if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
366 config |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
367 if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
368 config |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
369
370 data->config = config;
371 return;
372
373no_config:
374#endif
375 data->config = ULONG_MAX;
376}
377
378/*
379 * open "/proc/fs/fscache/objects" to provide a list of active objects
380 * - can be configured by a user-defined key added to the caller's keyrings
381 */
382static int fscache_objlist_open(struct inode *inode, struct file *file)
383{
384 struct fscache_objlist_data *data;
385
386 data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
387 if (!data)
388 return -ENOMEM;
389
390 /* get the configuration key */
391 fscache_objlist_config(data);
392
393 return 0;
394}
395
396/*
397 * clean up on close
398 */
399static int fscache_objlist_release(struct inode *inode, struct file *file)
400{
401 struct seq_file *m = file->private_data;
402
403 kfree(m->private);
404 m->private = NULL;
405 return seq_release(inode, file);
406}
407
408const struct file_operations fscache_objlist_fops = {
409 .open = fscache_objlist_open,
410 .read = seq_read,
411 .llseek = seq_lseek,
412 .release = fscache_objlist_release,
413};