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 *)(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(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 };