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         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                         sprintf(_type, "%02u", cookie->def->type);
 266                         type = _type;
 267                         break;
 268                 }
 269
 270                 seq_printf(m, "%-16s %s %2lx %16p",
 271                            cookie->def->name,
 272                            type,
 273                            cookie->flags,
 274                            cookie->netfs_data);
 275
 276                 if (cookie->def->get_key &&
 277                     config & FSCACHE_OBJLIST_CONFIG_KEY)
 278                         keylen = cookie->def->get_key(cookie->netfs_data,
 279                                                       buf, 400);
 280
 281                 if (cookie->def->get_aux &&
 282                     config & FSCACHE_OBJLIST_CONFIG_AUX)
 283                         auxlen = cookie->def->get_aux(cookie->netfs_data,
 284                                                       buf + keylen, 512 - keylen);
 285                 fscache_unuse_cookie(obj);
 286
 287                 if (keylen > 0 || auxlen > 0) {
 288                         seq_puts(m, " ");
 289                         for (p = buf; keylen > 0; keylen--)
 290                                 seq_printf(m, "%02x", *p++);
 291                         if (auxlen > 0) {
 292                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 293                                         seq_puts(m, ", ");
 294                                 for (; auxlen > 0; auxlen--)
 295                                         seq_printf(m, "%02x", *p++);
 296                         }
 297                 }
 298
 299                 seq_puts(m, "\n");
 300         } else {
 301                 seq_puts(m, "<no_netfs>\n");
 302         }
 303         return 0;
 304 }
 305
 306 static const struct seq_operations fscache_objlist_ops = {
 307         .start          = fscache_objlist_start,
 308         .stop           = fscache_objlist_stop,
 309         .next           = fscache_objlist_next,
 310         .show           = fscache_objlist_show,
 311 };
 312
 313 /*
 314  * get the configuration for filtering the list
 315  */
 316 static void fscache_objlist_config(struct fscache_objlist_data *data)
 317 {
 318 #ifdef CONFIG_KEYS
 319         const struct user_key_payload *confkey;
 320         unsigned long config;
 321         struct key *key;
 322         const char *buf;
 323         int len;
 324
 325         key = request_key(&key_type_user, "fscache:objlist", NULL);
 326         if (IS_ERR(key))
 327                 goto no_config;
 328
 329         config = 0;
 330         rcu_read_lock();
 331
 332         confkey = user_key_payload(key);
 333         if (!confkey) {
 334                 /* key was revoked */
 335                 rcu_read_unlock();
 336                 key_put(key);
 337                 goto no_config;
 338         }
 339
 340         buf = confkey->data;
 341
 342         for (len = confkey->datalen - 1; len >= 0; len--) {
 343                 switch (buf[len]) {
 344                 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;         break;
 345                 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;         break;
 346                 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;      break;
 347                 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;    break;
 348                 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;        break;
 349                 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;        break;
 350                 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;      break;
 351                 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;    break;
 352                 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;       break;
 353                 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;     break;
 354                 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;        break;
 355                 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;      break;
 356                 }
 357         }
 358
 359         rcu_read_unlock();
 360         key_put(key);
 361
 362         if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
 363             config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
 364         if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
 365             config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
 366         if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
 367             config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
 368         if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
 369             config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
 370         if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
 371             config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
 372         if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
 373             config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
 374
 375         data->config = config;
 376         return;
 377
 378 no_config:
 379 #endif
 380         data->config = ULONG_MAX;
 381 }
 382
 383 /*
 384  * open "/proc/fs/fscache/objects" to provide a list of active objects
 385  * - can be configured by a user-defined key added to the caller's keyrings
 386  */
 387 static int fscache_objlist_open(struct inode *inode, struct file *file)
 388 {
 389         struct fscache_objlist_data *data;
 390
 391         data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
 392         if (!data)
 393                 return -ENOMEM;
 394
 395         /* get the configuration key */
 396         fscache_objlist_config(data);
 397
 398         return 0;
 399 }
 400
 401 /*
 402  * clean up on close
 403  */
 404 static int fscache_objlist_release(struct inode *inode, struct file *file)
 405 {
 406         struct seq_file *m = file->private_data;
 407
 408         kfree(m->private);
 409         m->private = NULL;
 410         return seq_release(inode, file);
 411 }
 412
 413 const struct file_operations fscache_objlist_fops = {
 414         .owner          = THIS_MODULE,
 415         .open           = fscache_objlist_open,
 416         .read           = seq_read,
 417         .llseek         = seq_lseek,
 418         .release        = fscache_objlist_release,
 419 };