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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         ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
 54 
 55         write_lock(&fscache_object_list_lock);
 56 
 57         while (*p) {
 58                 parent = *p;
 59                 xobj = rb_entry(parent, struct fscache_object, objlist_link);
 60 
 61                 if (obj < xobj)
 62                         p = &(*p)->rb_left;
 63                 else if (obj > xobj)
 64                         p = &(*p)->rb_right;
 65                 else
 66                         BUG();
 67         }
 68 
 69         rb_link_node(&obj->objlist_link, parent, p);
 70         rb_insert_color(&obj->objlist_link, &fscache_object_list);
 71 
 72         write_unlock(&fscache_object_list_lock);
 73 }
 74 
 75 /*
 76  * Remove an object from the object list.
 77  */
 78 void fscache_objlist_remove(struct fscache_object *obj)
 79 {
 80         if (RB_EMPTY_NODE(&obj->objlist_link))
 81                 return;
 82 
 83         write_lock(&fscache_object_list_lock);
 84 
 85         BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
 86         rb_erase(&obj->objlist_link, &fscache_object_list);
 87 
 88         write_unlock(&fscache_object_list_lock);
 89 }
 90 
 91 /*
 92  * find the object in the tree on or after the specified index
 93  */
 94 static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
 95 {
 96         struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
 97         struct rb_node *p;
 98         unsigned long pos;
 99 
100         if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
101                 return NULL;
102         pos = *_pos;
103 
104         /* banners (can't represent line 0 by pos 0 as that would involve
105          * returning a NULL pointer) */
106         if (pos == 0)
107                 return (struct fscache_object *)(long)++(*_pos);
108         if (pos < 3)
109                 return (struct fscache_object *)pos;
110 
111         pobj = (struct fscache_object *)pos;
112         p = fscache_object_list.rb_node;
113         while (p) {
114                 obj = rb_entry(p, struct fscache_object, objlist_link);
115                 if (pobj < obj) {
116                         if (!minobj || minobj > obj)
117                                 minobj = obj;
118                         p = p->rb_left;
119                 } else if (pobj > obj) {
120                         p = p->rb_right;
121                 } else {
122                         minobj = obj;
123                         break;
124                 }
125                 obj = NULL;
126         }
127 
128         if (!minobj)
129                 *_pos = (unsigned long) ERR_PTR(-ENOENT);
130         else if (minobj != obj)
131                 *_pos = (unsigned long) minobj;
132         return minobj;
133 }
134 
135 /*
136  * set up the iterator to start reading from the first line
137  */
138 static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
139         __acquires(&fscache_object_list_lock)
140 {
141         read_lock(&fscache_object_list_lock);
142         return fscache_objlist_lookup(_pos);
143 }
144 
145 /*
146  * move to the next line
147  */
148 static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
149 {
150         (*_pos)++;
151         return fscache_objlist_lookup(_pos);
152 }
153 
154 /*
155  * clean up after reading
156  */
157 static void fscache_objlist_stop(struct seq_file *m, void *v)
158         __releases(&fscache_object_list_lock)
159 {
160         read_unlock(&fscache_object_list_lock);
161 }
162 
163 /*
164  * display an object
165  */
166 static int fscache_objlist_show(struct seq_file *m, void *v)
167 {
168         struct fscache_objlist_data *data = m->private;
169         struct fscache_object *obj = v;
170         struct fscache_cookie *cookie;
171         unsigned long config = data->config;
172         char _type[3], *type;
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 FL 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         cookie = obj->cookie;
220         if (~config) {
221                 FILTER(cookie->def,
222                        COOKIE, NOCOOKIE);
223                 FILTER(fscache_object_is_active(obj) ||
224                        obj->n_ops != 0 ||
225                        obj->n_obj_ops != 0 ||
226                        obj->flags ||
227                        !list_empty(&obj->dependents),
228                        BUSY, IDLE);
229                 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
230                        PENDWR, NOPENDWR);
231                 FILTER(atomic_read(&obj->n_reads),
232                        READS, NOREADS);
233                 FILTER(obj->events & obj->event_mask,
234                        EVENTS, NOEVENTS);
235                 FILTER(work_busy(&obj->work), WORK, NOWORK);
236         }
237 
238         seq_printf(m,
239                    "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
240                    obj->debug_id,
241                    obj->parent ? obj->parent->debug_id : -1,
242                    obj->state->short_name,
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,
250                    obj->events,
251                    obj->flags,
252                    work_busy(&obj->work));
253 
254         if (fscache_use_cookie(obj)) {
255                 uint16_t keylen = 0, auxlen = 0;
256 
257                 switch (cookie->def->type) {
258                 case 0:
259                         type = "IX";
260                         break;
261                 case 1:
262                         type = "DT";
263                         break;
264                 default:
265                         snprintf(_type, sizeof(_type), "%02u",
266                                  cookie->def->type);
267                         type = _type;
268                         break;
269                 }
270 
271                 seq_printf(m, "%-16s %s %2lx %16p",
272                            cookie->def->name,
273                            type,
274                            cookie->flags,
275                            cookie->netfs_data);
276 
277                 if (cookie->def->get_key &&
278                     config & FSCACHE_OBJLIST_CONFIG_KEY)
279                         keylen = cookie->def->get_key(cookie->netfs_data,
280                                                       buf, 400);
281 
282                 if (cookie->def->get_aux &&
283                     config & FSCACHE_OBJLIST_CONFIG_AUX)
284                         auxlen = cookie->def->get_aux(cookie->netfs_data,
285                                                       buf + keylen, 512 - keylen);
286                 fscache_unuse_cookie(obj);
287 
288                 if (keylen > 0 || auxlen > 0) {
289                         seq_puts(m, " ");
290                         for (p = buf; keylen > 0; keylen--)
291                                 seq_printf(m, "%02x", *p++);
292                         if (auxlen > 0) {
293                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
294                                         seq_puts(m, ", ");
295                                 for (; auxlen > 0; auxlen--)
296                                         seq_printf(m, "%02x", *p++);
297                         }
298                 }
299 
300                 seq_puts(m, "\n");
301         } else {
302                 seq_puts(m, "<no_netfs>\n");
303         }
304         return 0;
305 }
306 
307 static const struct seq_operations fscache_objlist_ops = {
308         .start          = fscache_objlist_start,
309         .stop           = fscache_objlist_stop,
310         .next           = fscache_objlist_next,
311         .show           = fscache_objlist_show,
312 };
313 
314 /*
315  * get the configuration for filtering the list
316  */
317 static void fscache_objlist_config(struct fscache_objlist_data *data)
318 {
319 #ifdef CONFIG_KEYS
320         const struct user_key_payload *confkey;
321         unsigned long config;
322         struct key *key;
323         const char *buf;
324         int len;
325 
326         key = request_key(&key_type_user, "fscache:objlist", NULL);
327         if (IS_ERR(key))
328                 goto no_config;
329 
330         config = 0;
331         rcu_read_lock();
332 
333         confkey = user_key_payload_rcu(key);
334         if (!confkey) {
335                 /* key was revoked */
336                 rcu_read_unlock();
337                 key_put(key);
338                 goto no_config;
339         }
340 
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 
392         data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
393         if (!data)
394                 return -ENOMEM;
395 
396         /* get the configuration key */
397         fscache_objlist_config(data);
398 
399         return 0;
400 }
401 
402 /*
403  * clean up on close
404  */
405 static int fscache_objlist_release(struct inode *inode, struct file *file)
406 {
407         struct seq_file *m = file->private_data;
408 
409         kfree(m->private);
410         m->private = NULL;
411         return seq_release(inode, file);
412 }
413 
414 const struct file_operations fscache_objlist_fops = {
415         .open           = fscache_objlist_open,
416         .read           = seq_read,
417         .llseek         = seq_lseek,
418         .release        = fscache_objlist_release,
419 };
420 

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