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 work */
  38 #define FSCACHE_OBJLIST_CONFIG_NOWORK   0x00002000      /* show objects without work */
  39 };
  40
  41 /*
  42  * Add an object to the object list
  43  * - we use the address of the fscache_object structure as the key into the
  44  *   tree
  45  */
  46 void fscache_objlist_add(struct fscache_object *obj)
  47 {
  48         struct fscache_object *xobj;
  49         struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
  50
  51         ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
  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  * Remove an object from the object list.
  75  */
  76 void fscache_objlist_remove(struct fscache_object *obj)
  77 {
  78         if (RB_EMPTY_NODE(&obj->objlist_link))
  79                 return;
  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
  89 /*
  90  * find the object in the tree on or after the specified index
  91  */
  92 static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
  93 {
  94         struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
  95         struct rb_node *p;
  96         unsigned long pos;
  97
  98         if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
  99                 return NULL;
 100         pos = *_pos;
 101
 102         /* banners (can't represent line 0 by pos 0 as that would involve
 103          * returning a NULL pointer) */
 104         if (pos == 0)
 105                 return (struct fscache_object *)(long)++(*_pos);
 106         if (pos < 3)
 107                 return (struct fscache_object *)pos;
 108
 109         pobj = (struct fscache_object *)pos;
 110         p = fscache_object_list.rb_node;
 111         while (p) {
 112                 obj = rb_entry(p, struct fscache_object, objlist_link);
 113                 if (pobj < obj) {
 114                         if (!minobj || minobj > obj)
 115                                 minobj = obj;
 116                         p = p->rb_left;
 117                 } else if (pobj > obj) {
 118                         p = p->rb_right;
 119                 } else {
 120                         minobj = obj;
 121                         break;
 122                 }
 123                 obj = NULL;
 124         }
 125
 126         if (!minobj)
 127                 *_pos = (unsigned long) ERR_PTR(-ENOENT);
 128         else if (minobj != obj)
 129                 *_pos = (unsigned long) minobj;
 130         return minobj;
 131 }
 132
 133 /*
 134  * set up the iterator to start reading from the first line
 135  */
 136 static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
 137         __acquires(&fscache_object_list_lock)
 138 {
 139         read_lock(&fscache_object_list_lock);
 140         return fscache_objlist_lookup(_pos);
 141 }
 142
 143 /*
 144  * move to the next line
 145  */
 146 static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
 147 {
 148         (*_pos)++;
 149         return fscache_objlist_lookup(_pos);
 150 }
 151
 152 /*
 153  * clean up after reading
 154  */
 155 static void fscache_objlist_stop(struct seq_file *m, void *v)
 156         __releases(&fscache_object_list_lock)
 157 {
 158         read_unlock(&fscache_object_list_lock);
 159 }
 160
 161 /*
 162  * display an object
 163  */
 164 static int fscache_objlist_show(struct seq_file *m, void *v)
 165 {
 166         struct fscache_objlist_data *data = m->private;
 167         struct fscache_object *obj = v;
 168         struct fscache_cookie *cookie;
 169         unsigned long config = data->config;
 170         char _type[3], *type;
 171         u8 *p;
 172
 173         if ((unsigned long) v == 1) {
 174                 seq_puts(m, "OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS"
 175                          " EM EV FL S"
 176                          " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
 177                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
 178                               FSCACHE_OBJLIST_CONFIG_AUX))
 179                         seq_puts(m, "       ");
 180                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 181                         seq_puts(m, "OBJECT_KEY");
 182                 if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
 183                                FSCACHE_OBJLIST_CONFIG_AUX)) ==
 184                     (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
 185                         seq_puts(m, ", ");
 186                 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
 187                         seq_puts(m, "AUX_DATA");
 188                 seq_puts(m, "\n");
 189                 return 0;
 190         }
 191
 192         if ((unsigned long) v == 2) {
 193                 seq_puts(m, "======== ======== ==== ===== === === === == ====="
 194                          " == == == ="
 195                          " | ================ == == ================");
 196                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
 197                               FSCACHE_OBJLIST_CONFIG_AUX))
 198                         seq_puts(m, " ================");
 199                 seq_puts(m, "\n");
 200                 return 0;
 201         }
 202
 203         /* filter out any unwanted objects */
 204 #define FILTER(criterion, _yes, _no)                                    \
 205         do {                                                            \
 206                 unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes;      \
 207                 unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no;        \
 208                 if (criterion) {                                        \
 209                         if (!(config & yes))                            \
 210                                 return 0;                               \
 211                 } else {                                                \
 212                         if (!(config & no))                             \
 213                                 return 0;                               \
 214                 }                                                       \
 215         } while(0)
 216
 217         cookie = obj->cookie;
 218         if (~config) {
 219                 FILTER(cookie->def,
 220                        COOKIE, NOCOOKIE);
 221                 FILTER(fscache_object_is_active(obj) ||
 222                        obj->n_ops != 0 ||
 223                        obj->n_obj_ops != 0 ||
 224                        obj->flags ||
 225                        !list_empty(&obj->dependents),
 226                        BUSY, IDLE);
 227                 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
 228                        PENDWR, NOPENDWR);
 229                 FILTER(atomic_read(&obj->n_reads),
 230                        READS, NOREADS);
 231                 FILTER(obj->events & obj->event_mask,
 232                        EVENTS, NOEVENTS);
 233                 FILTER(work_busy(&obj->work), WORK, NOWORK);
 234         }
 235
 236         seq_printf(m,
 237                    "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
 238                    obj->debug_id,
 239                    obj->parent ? obj->parent->debug_id : -1,
 240                    obj->state->short_name,
 241                    obj->n_children,
 242                    obj->n_ops,
 243                    obj->n_obj_ops,
 244                    obj->n_in_progress,
 245                    obj->n_exclusive,
 246                    atomic_read(&obj->n_reads),
 247                    obj->event_mask,
 248                    obj->events,
 249                    obj->flags,
 250                    work_busy(&obj->work));
 251
 252         if (fscache_use_cookie(obj)) {
 253                 uint16_t keylen = 0, auxlen = 0;
 254
 255                 switch (cookie->type) {
 256                 case 0:
 257                         type = "IX";
 258                         break;
 259                 case 1:
 260                         type = "DT";
 261                         break;
 262                 default:
 263                         snprintf(_type, sizeof(_type), "%02u",
 264                                  cookie->type);
 265                         type = _type;
 266                         break;
 267                 }
 268
 269                 seq_printf(m, "%-16s %s %2lx %16p",
 270                            cookie->def->name,
 271                            type,
 272                            cookie->flags,
 273                            cookie->netfs_data);
 274
 275                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 276                         keylen = cookie->key_len;
 277
 278                 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
 279                         auxlen = cookie->aux_len;
 280
 281                 if (keylen > 0 || auxlen > 0) {
 282                         seq_puts(m, " ");
 283                         p = keylen <= sizeof(cookie->inline_key) ?
 284                                 cookie->inline_key : cookie->key;
 285                         for (; keylen > 0; keylen--)
 286                                 seq_printf(m, "%02x", *p++);
 287                         if (auxlen > 0) {
 288                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 289                                         seq_puts(m, ", ");
 290                                 p = auxlen <= sizeof(cookie->inline_aux) ?
 291                                         cookie->inline_aux : cookie->aux;
 292                                 for (; auxlen > 0; auxlen--)
 293                                         seq_printf(m, "%02x", *p++);
 294                         }
 295                 }
 296
 297                 seq_puts(m, "\n");
 298                 fscache_unuse_cookie(obj);
 299         } else {
 300                 seq_puts(m, "<no_netfs>\n");
 301         }
 302         return 0;
 303 }
 304
 305 static const struct seq_operations fscache_objlist_ops = {
 306         .start          = fscache_objlist_start,
 307         .stop           = fscache_objlist_stop,
 308         .next           = fscache_objlist_next,
 309         .show           = fscache_objlist_show,
 310 };
 311
 312 /*
 313  * get the configuration for filtering the list
 314  */
 315 static void fscache_objlist_config(struct fscache_objlist_data *data)
 316 {
 317 #ifdef CONFIG_KEYS
 318         const struct user_key_payload *confkey;
 319         unsigned long config;
 320         struct key *key;
 321         const char *buf;
 322         int len;
 323
 324         key = request_key(&key_type_user, "fscache:objlist", NULL);
 325         if (IS_ERR(key))
 326                 goto no_config;
 327
 328         config = 0;
 329         rcu_read_lock();
 330
 331         confkey = user_key_payload_rcu(key);
 332         if (!confkey) {
 333                 /* key was revoked */
 334                 rcu_read_unlock();
 335                 key_put(key);
 336                 goto no_config;
 337         }
 338
 339         buf = confkey->data;
 340
 341         for (len = confkey->datalen - 1; len >= 0; len--) {
 342                 switch (buf[len]) {
 343                 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;         break;
 344                 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;         break;
 345                 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;      break;
 346                 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;    break;
 347                 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;        break;
 348                 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;        break;
 349                 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;      break;
 350                 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;    break;
 351                 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;       break;
 352                 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;     break;
 353                 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;        break;
 354                 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;      break;
 355                 }
 356         }
 357
 358         rcu_read_unlock();
 359         key_put(key);
 360
 361         if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
 362             config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
 363         if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
 364             config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
 365         if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
 366             config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
 367         if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
 368             config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
 369         if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
 370             config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
 371         if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
 372             config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
 373
 374         data->config = config;
 375         return;
 376
 377 no_config:
 378 #endif
 379         data->config = ULONG_MAX;
 380 }
 381
 382 /*
 383  * open "/proc/fs/fscache/objects" to provide a list of active objects
 384  * - can be configured by a user-defined key added to the caller's keyrings
 385  */
 386 static int fscache_objlist_open(struct inode *inode, struct file *file)
 387 {
 388         struct fscache_objlist_data *data;
 389
 390         data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
 391         if (!data)
 392                 return -ENOMEM;
 393
 394         /* get the configuration key */
 395         fscache_objlist_config(data);
 396
 397         return 0;
 398 }
 399
 400 /*
 401  * clean up on close
 402  */
 403 static int fscache_objlist_release(struct inode *inode, struct file *file)
 404 {
 405         struct seq_file *m = file->private_data;
 406
 407         kfree(m->private);
 408         m->private = NULL;
 409         return seq_release(inode, file);
 410 }
 411
 412 const struct file_operations fscache_objlist_fops = {
 413         .open           = fscache_objlist_open,
 414         .read           = seq_read,
 415         .llseek         = seq_lseek,
 416         .release        = fscache_objlist_release,
 417 };