fs/fscache/object-list.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Global fscache object list maintainer and viewer
   3  *
   4  * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #define FSCACHE_DEBUG_LEVEL COOKIE
   9 #include <linux/module.h>
  10 #include <linux/proc_fs.h>
  11 #include <linux/seq_file.h>
  12 #include <linux/slab.h>
  13 #include <linux/key.h>
  14 #include <keys/user-type.h>
  15 #include "internal.h"
  16
  17 static struct rb_root fscache_object_list;
  18 static DEFINE_RWLOCK(fscache_object_list_lock);
  19
  20 struct fscache_objlist_data {
  21         unsigned long   config;         /* display configuration */
  22 #define FSCACHE_OBJLIST_CONFIG_KEY      0x00000001      /* show object keys */
  23 #define FSCACHE_OBJLIST_CONFIG_AUX      0x00000002      /* show object auxdata */
  24 #define FSCACHE_OBJLIST_CONFIG_COOKIE   0x00000004      /* show objects with cookies */
  25 #define FSCACHE_OBJLIST_CONFIG_NOCOOKIE 0x00000008      /* show objects without cookies */
  26 #define FSCACHE_OBJLIST_CONFIG_BUSY     0x00000010      /* show busy objects */
  27 #define FSCACHE_OBJLIST_CONFIG_IDLE     0x00000020      /* show idle objects */
  28 #define FSCACHE_OBJLIST_CONFIG_PENDWR   0x00000040      /* show objects with pending writes */
  29 #define FSCACHE_OBJLIST_CONFIG_NOPENDWR 0x00000080      /* show objects without pending writes */
  30 #define FSCACHE_OBJLIST_CONFIG_READS    0x00000100      /* show objects with active reads */
  31 #define FSCACHE_OBJLIST_CONFIG_NOREADS  0x00000200      /* show objects without active reads */
  32 #define FSCACHE_OBJLIST_CONFIG_EVENTS   0x00000400      /* show objects with events */
  33 #define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800      /* show objects without no events */
  34 #define FSCACHE_OBJLIST_CONFIG_WORK     0x00001000      /* show objects with work */
  35 #define FSCACHE_OBJLIST_CONFIG_NOWORK   0x00002000      /* show objects without work */
  36 };
  37
  38 /*
  39  * Add an object to the object list
  40  * - we use the address of the fscache_object structure as the key into the
  41  *   tree
  42  */
  43 void fscache_objlist_add(struct fscache_object *obj)
  44 {
  45         struct fscache_object *xobj;
  46         struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
  47
  48         ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
  49
  50         write_lock(&fscache_object_list_lock);
  51
  52         while (*p) {
  53                 parent = *p;
  54                 xobj = rb_entry(parent, struct fscache_object, objlist_link);
  55
  56                 if (obj < xobj)
  57                         p = &(*p)->rb_left;
  58                 else if (obj > xobj)
  59                         p = &(*p)->rb_right;
  60                 else
  61                         BUG();
  62         }
  63
  64         rb_link_node(&obj->objlist_link, parent, p);
  65         rb_insert_color(&obj->objlist_link, &fscache_object_list);
  66
  67         write_unlock(&fscache_object_list_lock);
  68 }
  69
  70 /*
  71  * Remove an object from the object list.
  72  */
  73 void fscache_objlist_remove(struct fscache_object *obj)
  74 {
  75         if (RB_EMPTY_NODE(&obj->objlist_link))
  76                 return;
  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 *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->type) {
 253                 case 0:
 254                         type = "IX";
 255                         break;
 256                 case 1:
 257                         type = "DT";
 258                         break;
 259                 default:
 260                         snprintf(_type, sizeof(_type), "%02u",
 261                                  cookie->type);
 262                         type = _type;
 263                         break;
 264                 }
 265
 266                 seq_printf(m, "%-16s %s %2lx %16p",
 267                            cookie->def->name,
 268                            type,
 269                            cookie->flags,
 270                            cookie->netfs_data);
 271
 272                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 273                         keylen = cookie->key_len;
 274
 275                 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
 276                         auxlen = cookie->aux_len;
 277
 278                 if (keylen > 0 || auxlen > 0) {
 279                         seq_puts(m, " ");
 280                         p = keylen <= sizeof(cookie->inline_key) ?
 281                                 cookie->inline_key : cookie->key;
 282                         for (; keylen > 0; keylen--)
 283                                 seq_printf(m, "%02x", *p++);
 284                         if (auxlen > 0) {
 285                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 286                                         seq_puts(m, ", ");
 287                                 p = auxlen <= sizeof(cookie->inline_aux) ?
 288                                         cookie->inline_aux : cookie->aux;
 289                                 for (; auxlen > 0; auxlen--)
 290                                         seq_printf(m, "%02x", *p++);
 291                         }
 292                 }
 293
 294                 seq_puts(m, "\n");
 295                 fscache_unuse_cookie(obj);
 296         } else {
 297                 seq_puts(m, "<no_netfs>\n");
 298         }
 299         return 0;
 300 }
 301
 302 static const struct seq_operations fscache_objlist_ops = {
 303         .start          = fscache_objlist_start,
 304         .stop           = fscache_objlist_stop,
 305         .next           = fscache_objlist_next,
 306         .show           = fscache_objlist_show,
 307 };
 308
 309 /*
 310  * get the configuration for filtering the list
 311  */
 312 static void fscache_objlist_config(struct fscache_objlist_data *data)
 313 {
 314 #ifdef CONFIG_KEYS
 315         const struct user_key_payload *confkey;
 316         unsigned long config;
 317         struct key *key;
 318         const char *buf;
 319         int len;
 320
 321         key = request_key(&key_type_user, "fscache:objlist", NULL);
 322         if (IS_ERR(key))
 323                 goto no_config;
 324
 325         config = 0;
 326         rcu_read_lock();
 327
 328         confkey = user_key_payload_rcu(key);
 329         if (!confkey) {
 330                 /* key was revoked */
 331                 rcu_read_unlock();
 332                 key_put(key);
 333                 goto no_config;
 334         }
 335
 336         buf = confkey->data;
 337
 338         for (len = confkey->datalen - 1; len >= 0; len--) {
 339                 switch (buf[len]) {
 340                 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;         break;
 341                 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;         break;
 342                 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;      break;
 343                 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;    break;
 344                 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;        break;
 345                 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;        break;
 346                 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;      break;
 347                 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;    break;
 348                 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;       break;
 349                 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;     break;
 350                 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;        break;
 351                 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;      break;
 352                 }
 353         }
 354
 355         rcu_read_unlock();
 356         key_put(key);
 357
 358         if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
 359             config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
 360         if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
 361             config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
 362         if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
 363             config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
 364         if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
 365             config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
 366         if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
 367             config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
 368         if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
 369             config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
 370
 371         data->config = config;
 372         return;
 373
 374 no_config:
 375 #endif
 376         data->config = ULONG_MAX;
 377 }
 378
 379 /*
 380  * open "/proc/fs/fscache/objects" to provide a list of active objects
 381  * - can be configured by a user-defined key added to the caller's keyrings
 382  */
 383 static int fscache_objlist_open(struct inode *inode, struct file *file)
 384 {
 385         struct fscache_objlist_data *data;
 386
 387         data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
 388         if (!data)
 389                 return -ENOMEM;
 390
 391         /* get the configuration key */
 392         fscache_objlist_config(data);
 393
 394         return 0;
 395 }
 396
 397 /*
 398  * clean up on close
 399  */
 400 static int fscache_objlist_release(struct inode *inode, struct file *file)
 401 {
 402         struct seq_file *m = file->private_data;
 403
 404         kfree(m->private);
 405         m->private = NULL;
 406         return seq_release(inode, file);
 407 }
 408
 409 const struct proc_ops fscache_objlist_proc_ops = {
 410         .proc_open      = fscache_objlist_open,
 411         .proc_read      = seq_read,
 412         .proc_lseek     = seq_lseek,
 413         .proc_release   = fscache_objlist_release,
 414 };