1e1f286dd70eeb0ea7e98b46012e378280e0cf58
[linux-3.10.git] / fs / fscache / object-list.c
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 slow work */
38 #define FSCACHE_OBJLIST_CONFIG_NOWORK   0x00002000      /* show objects without slow 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
73 /**
74  * fscache_object_destroy - Note that a cache object is about to be destroyed
75  * @object: The object to be destroyed
76  *
77  * Note the imminent destruction and deallocation of a cache object record.
78  */
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 *) ++(*_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(obj->work.flags & ~(1UL << SLOW_WORK_VERY_SLOW),
235                        WORK, NOWORK);
236         }
237
238         seq_printf(m,
239                    "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1lx | ",
240                    obj->debug_id,
241                    obj->parent ? obj->parent->debug_id : -1,
242                    fscache_object_states_short[obj->state],
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 & FSCACHE_OBJECT_EVENTS_MASK,
250                    obj->events,
251                    obj->flags,
252                    obj->work.flags);
253
254         no_cookie = true;
255         keylen = auxlen = 0;
256         if (obj->cookie) {
257                 spin_lock(&obj->lock);
258                 if (obj->cookie) {
259                         switch (obj->cookie->def->type) {
260                         case 0:
261                                 type = "IX";
262                                 break;
263                         case 1:
264                                 type = "DT";
265                                 break;
266                         default:
267                                 sprintf(_type, "%02u",
268                                         obj->cookie->def->type);
269                                 type = _type;
270                                 break;
271                         }
272
273                         seq_printf(m, "%-16s %s %2lx %16p",
274                                    obj->cookie->def->name,
275                                    type,
276                                    obj->cookie->flags,
277                                    obj->cookie->netfs_data);
278
279                         if (obj->cookie->def->get_key &&
280                             config & FSCACHE_OBJLIST_CONFIG_KEY)
281                                 keylen = obj->cookie->def->get_key(
282                                         obj->cookie->netfs_data,
283                                         buf, 400);
284
285                         if (obj->cookie->def->get_aux &&
286                             config & FSCACHE_OBJLIST_CONFIG_AUX)
287                                 auxlen = obj->cookie->def->get_aux(
288                                         obj->cookie->netfs_data,
289                                         buf + keylen, 512 - keylen);
290
291                         no_cookie = false;
292                 }
293                 spin_unlock(&obj->lock);
294
295                 if (!no_cookie && (keylen > 0 || auxlen > 0)) {
296                         seq_printf(m, " ");
297                         for (p = buf; keylen > 0; keylen--)
298                                 seq_printf(m, "%02x", *p++);
299                         if (auxlen > 0) {
300                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
301                                         seq_printf(m, ", ");
302                                 for (; auxlen > 0; auxlen--)
303                                         seq_printf(m, "%02x", *p++);
304                         }
305                 }
306         }
307
308         if (no_cookie)
309                 seq_printf(m, "<no_cookie>\n");
310         else
311                 seq_printf(m, "\n");
312         return 0;
313 }
314
315 static const struct seq_operations fscache_objlist_ops = {
316         .start          = fscache_objlist_start,
317         .stop           = fscache_objlist_stop,
318         .next           = fscache_objlist_next,
319         .show           = fscache_objlist_show,
320 };
321
322 /*
323  * get the configuration for filtering the list
324  */
325 static void fscache_objlist_config(struct fscache_objlist_data *data)
326 {
327 #ifdef CONFIG_KEYS
328         struct user_key_payload *confkey;
329         unsigned long config;
330         struct key *key;
331         const char *buf;
332         int len;
333
334         key = request_key(&key_type_user, "fscache:objlist", NULL);
335         if (IS_ERR(key))
336                 goto no_config;
337
338         config = 0;
339         rcu_read_lock();
340
341         confkey = key->payload.data;
342         buf = confkey->data;
343
344         for (len = confkey->datalen - 1; len >= 0; len--) {
345                 switch (buf[len]) {
346                 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;         break;
347                 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;         break;
348                 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;      break;
349                 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;    break;
350                 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;        break;
351                 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;        break;
352                 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;      break;
353                 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;    break;
354                 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;       break;
355                 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;     break;
356                 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;        break;
357                 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;      break;
358                 }
359         }
360
361         rcu_read_unlock();
362         key_put(key);
363
364         if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
365             config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
366         if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
367             config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
368         if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
369             config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
370         if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
371             config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
372         if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
373             config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
374         if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
375             config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
376
377         data->config = config;
378         return;
379
380 no_config:
381 #endif
382         data->config = ULONG_MAX;
383 }
384
385 /*
386  * open "/proc/fs/fscache/objects" to provide a list of active objects
387  * - can be configured by a user-defined key added to the caller's keyrings
388  */
389 static int fscache_objlist_open(struct inode *inode, struct file *file)
390 {
391         struct fscache_objlist_data *data;
392         struct seq_file *m;
393         int ret;
394
395         ret = seq_open(file, &fscache_objlist_ops);
396         if (ret < 0)
397                 return ret;
398
399         m = file->private_data;
400
401         /* buffer for key extraction */
402         data = kmalloc(sizeof(struct fscache_objlist_data), GFP_KERNEL);
403         if (!data) {
404                 seq_release(inode, file);
405                 return -ENOMEM;
406         }
407
408         /* get the configuration key */
409         fscache_objlist_config(data);
410
411         m->private = data;
412         return 0;
413 }
414
415 /*
416  * clean up on close
417  */
418 static int fscache_objlist_release(struct inode *inode, struct file *file)
419 {
420         struct seq_file *m = file->private_data;
421
422         kfree(m->private);
423         m->private = NULL;
424         return seq_release(inode, file);
425 }
426
427 const struct file_operations fscache_objlist_fops = {
428         .owner          = THIS_MODULE,
429         .open           = fscache_objlist_open,
430         .read           = seq_read,
431         .llseek         = seq_lseek,
432         .release        = fscache_objlist_release,
433 };