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         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         write_lock(&fscache_object_list_lock);
  79
  80         BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
  81         rb_erase(&obj->objlist_link, &fscache_object_list);
  82
  83         write_unlock(&fscache_object_list_lock);
  84 }
  85
  86 /*
  87  * find the object in the tree on or after the specified index
  88  */
  89 static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
  90 {
  91         struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
  92         struct rb_node *p;
  93         unsigned long pos;
  94
  95         if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
  96                 return NULL;
  97         pos = *_pos;
  98
  99         /* banners (can't represent line 0 by pos 0 as that would involve
 100          * returning a NULL pointer) */
 101         if (pos == 0)
 102                 return (struct fscache_object *)(long)++(*_pos);
 103         if (pos < 3)
 104                 return (struct fscache_object *)pos;
 105
 106         pobj = (struct fscache_object *)pos;
 107         p = fscache_object_list.rb_node;
 108         while (p) {
 109                 obj = rb_entry(p, struct fscache_object, objlist_link);
 110                 if (pobj < obj) {
 111                         if (!minobj || minobj > obj)
 112                                 minobj = obj;
 113                         p = p->rb_left;
 114                 } else if (pobj > obj) {
 115                         p = p->rb_right;
 116                 } else {
 117                         minobj = obj;
 118                         break;
 119                 }
 120                 obj = NULL;
 121         }
 122
 123         if (!minobj)
 124                 *_pos = (unsigned long) ERR_PTR(-ENOENT);
 125         else if (minobj != obj)
 126                 *_pos = (unsigned long) minobj;
 127         return minobj;
 128 }
 129
 130 /*
 131  * set up the iterator to start reading from the first line
 132  */
 133 static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
 134         __acquires(&fscache_object_list_lock)
 135 {
 136         read_lock(&fscache_object_list_lock);
 137         return fscache_objlist_lookup(_pos);
 138 }
 139
 140 /*
 141  * move to the next line
 142  */
 143 static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
 144 {
 145         (*_pos)++;
 146         return fscache_objlist_lookup(_pos);
 147 }
 148
 149 /*
 150  * clean up after reading
 151  */
 152 static void fscache_objlist_stop(struct seq_file *m, void *v)
 153         __releases(&fscache_object_list_lock)
 154 {
 155         read_unlock(&fscache_object_list_lock);
 156 }
 157
 158 /*
 159  * display an object
 160  */
 161 static int fscache_objlist_show(struct seq_file *m, void *v)
 162 {
 163         struct fscache_objlist_data *data = m->private;
 164         struct fscache_object *obj = v;
 165         struct fscache_cookie *cookie;
 166         unsigned long config = data->config;
 167         char _type[3], *type;
 168         u8 *buf = data->buf, *p;
 169
 170         if ((unsigned long) v == 1) {
 171                 seq_puts(m, "OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS"
 172                          " EM EV FL S"
 173                          " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
 174                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
 175                               FSCACHE_OBJLIST_CONFIG_AUX))
 176                         seq_puts(m, "       ");
 177                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 178                         seq_puts(m, "OBJECT_KEY");
 179                 if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
 180                                FSCACHE_OBJLIST_CONFIG_AUX)) ==
 181                     (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
 182                         seq_puts(m, ", ");
 183                 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
 184                         seq_puts(m, "AUX_DATA");
 185                 seq_puts(m, "\n");
 186                 return 0;
 187         }
 188
 189         if ((unsigned long) v == 2) {
 190                 seq_puts(m, "======== ======== ==== ===== === === === == ====="
 191                          " == == == ="
 192                          " | ================ == == ================");
 193                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
 194                               FSCACHE_OBJLIST_CONFIG_AUX))
 195                         seq_puts(m, " ================");
 196                 seq_puts(m, "\n");
 197                 return 0;
 198         }
 199
 200         /* filter out any unwanted objects */
 201 #define FILTER(criterion, _yes, _no)                                    \
 202         do {                                                            \
 203                 unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes;      \
 204                 unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no;        \
 205                 if (criterion) {                                        \
 206                         if (!(config & yes))                            \
 207                                 return 0;                               \
 208                 } else {                                                \
 209                         if (!(config & no))                             \
 210                                 return 0;                               \
 211                 }                                                       \
 212         } while(0)
 213
 214         cookie = obj->cookie;
 215         if (~config) {
 216                 FILTER(cookie->def,
 217                        COOKIE, NOCOOKIE);
 218                 FILTER(fscache_object_is_active(obj) ||
 219                        obj->n_ops != 0 ||
 220                        obj->n_obj_ops != 0 ||
 221                        obj->flags ||
 222                        !list_empty(&obj->dependents),
 223                        BUSY, IDLE);
 224                 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
 225                        PENDWR, NOPENDWR);
 226                 FILTER(atomic_read(&obj->n_reads),
 227                        READS, NOREADS);
 228                 FILTER(obj->events & obj->event_mask,
 229                        EVENTS, NOEVENTS);
 230                 FILTER(work_busy(&obj->work), WORK, NOWORK);
 231         }
 232
 233         seq_printf(m,
 234                    "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
 235                    obj->debug_id,
 236                    obj->parent ? obj->parent->debug_id : -1,
 237                    obj->state->short_name,
 238                    obj->n_children,
 239                    obj->n_ops,
 240                    obj->n_obj_ops,
 241                    obj->n_in_progress,
 242                    obj->n_exclusive,
 243                    atomic_read(&obj->n_reads),
 244                    obj->event_mask,
 245                    obj->events,
 246                    obj->flags,
 247                    work_busy(&obj->work));
 248
 249         if (fscache_use_cookie(obj)) {
 250                 uint16_t keylen = 0, auxlen = 0;
 251
 252                 switch (cookie->def->type) {
 253                 case 0:
 254                         type = "IX";
 255                         break;
 256                 case 1:
 257                         type = "DT";
 258                         break;
 259                 default:
 260                         sprintf(_type, "%02u", cookie->def->type);
 261                         type = _type;
 262                         break;
 263                 }
 264
 265                 seq_printf(m, "%-16s %s %2lx %16p",
 266                            cookie->def->name,
 267                            type,
 268                            cookie->flags,
 269                            cookie->netfs_data);
 270
 271                 if (cookie->def->get_key &&
 272                     config & FSCACHE_OBJLIST_CONFIG_KEY)
 273                         keylen = cookie->def->get_key(cookie->netfs_data,
 274                                                       buf, 400);
 275
 276                 if (cookie->def->get_aux &&
 277                     config & FSCACHE_OBJLIST_CONFIG_AUX)
 278                         auxlen = cookie->def->get_aux(cookie->netfs_data,
 279                                                       buf + keylen, 512 - keylen);
 280                 fscache_unuse_cookie(obj);
 281
 282                 if (keylen > 0 || auxlen > 0) {
 283                         seq_printf(m, " ");
 284                         for (p = buf; keylen > 0; keylen--)
 285                                 seq_printf(m, "%02x", *p++);
 286                         if (auxlen > 0) {
 287                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 288                                         seq_printf(m, ", ");
 289                                 for (; auxlen > 0; auxlen--)
 290                                         seq_printf(m, "%02x", *p++);
 291                         }
 292                 }
 293
 294                 seq_printf(m, "\n");
 295         } else {
 296                 seq_printf(m, "<no_netfs>\n");
 297         }
 298         return 0;
 299 }
 300
 301 static const struct seq_operations fscache_objlist_ops = {
 302         .start          = fscache_objlist_start,
 303         .stop           = fscache_objlist_stop,
 304         .next           = fscache_objlist_next,
 305         .show           = fscache_objlist_show,
 306 };
 307
 308 /*
 309  * get the configuration for filtering the list
 310  */
 311 static void fscache_objlist_config(struct fscache_objlist_data *data)
 312 {
 313 #ifdef CONFIG_KEYS
 314         struct user_key_payload *confkey;
 315         unsigned long config;
 316         struct key *key;
 317         const char *buf;
 318         int len;
 319
 320         key = request_key(&key_type_user, "fscache:objlist", NULL);
 321         if (IS_ERR(key))
 322                 goto no_config;
 323
 324         config = 0;
 325         rcu_read_lock();
 326
 327         confkey = key->payload.data;
 328         buf = confkey->data;
 329
 330         for (len = confkey->datalen - 1; len >= 0; len--) {
 331                 switch (buf[len]) {
 332                 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;         break;
 333                 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;         break;
 334                 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;      break;
 335                 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;    break;
 336                 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;        break;
 337                 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;        break;
 338                 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;      break;
 339                 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;    break;
 340                 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;       break;
 341                 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;     break;
 342                 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;        break;
 343                 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;      break;
 344                 }
 345         }
 346
 347         rcu_read_unlock();
 348         key_put(key);
 349
 350         if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
 351             config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
 352         if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
 353             config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
 354         if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
 355             config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
 356         if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
 357             config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
 358         if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
 359             config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
 360         if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
 361             config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
 362
 363         data->config = config;
 364         return;
 365
 366 no_config:
 367 #endif
 368         data->config = ULONG_MAX;
 369 }
 370
 371 /*
 372  * open "/proc/fs/fscache/objects" to provide a list of active objects
 373  * - can be configured by a user-defined key added to the caller's keyrings
 374  */
 375 static int fscache_objlist_open(struct inode *inode, struct file *file)
 376 {
 377         struct fscache_objlist_data *data;
 378         struct seq_file *m;
 379         int ret;
 380
 381         ret = seq_open(file, &fscache_objlist_ops);
 382         if (ret < 0)
 383                 return ret;
 384
 385         m = file->private_data;
 386
 387         /* buffer for key extraction */
 388         data = kmalloc(sizeof(struct fscache_objlist_data), GFP_KERNEL);
 389         if (!data) {
 390                 seq_release(inode, file);
 391                 return -ENOMEM;
 392         }
 393
 394         /* get the configuration key */
 395         fscache_objlist_config(data);
 396
 397         m->private = data;
 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 };