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TOMOYO Linux Cross Reference
Linux/fs/fscache/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 (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 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 
 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 *)(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 };
433 

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