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