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/seq_file.h>
  11 #include <linux/slab.h>
  12 #include <linux/key.h>
  13 #include <keys/user-type.h>
  14 #include "internal.h"
  15
  16 static struct rb_root fscache_object_list;
  17 static DEFINE_RWLOCK(fscache_object_list_lock);
  18
  19 struct fscache_objlist_data {
  20         unsigned long   config;         /* display configuration */
  21 #define FSCACHE_OBJLIST_CONFIG_KEY      0x00000001      /* show object keys */
  22 #define FSCACHE_OBJLIST_CONFIG_AUX      0x00000002      /* show object auxdata */
  23 #define FSCACHE_OBJLIST_CONFIG_COOKIE   0x00000004      /* show objects with cookies */
  24 #define FSCACHE_OBJLIST_CONFIG_NOCOOKIE 0x00000008      /* show objects without cookies */
  25 #define FSCACHE_OBJLIST_CONFIG_BUSY     0x00000010      /* show busy objects */
  26 #define FSCACHE_OBJLIST_CONFIG_IDLE     0x00000020      /* show idle objects */
  27 #define FSCACHE_OBJLIST_CONFIG_PENDWR   0x00000040      /* show objects with pending writes */
  28 #define FSCACHE_OBJLIST_CONFIG_NOPENDWR 0x00000080      /* show objects without pending writes */
  29 #define FSCACHE_OBJLIST_CONFIG_READS    0x00000100      /* show objects with active reads */
  30 #define FSCACHE_OBJLIST_CONFIG_NOREADS  0x00000200      /* show objects without active reads */
  31 #define FSCACHE_OBJLIST_CONFIG_EVENTS   0x00000400      /* show objects with events */
  32 #define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800      /* show objects without no events */
  33 #define FSCACHE_OBJLIST_CONFIG_WORK     0x00001000      /* show objects with work */
  34 #define FSCACHE_OBJLIST_CONFIG_NOWORK   0x00002000      /* show objects without work */
  35 };
  36
  37 /*
  38  * Add an object to the object list
  39  * - we use the address of the fscache_object structure as the key into the
  40  *   tree
  41  */
  42 void fscache_objlist_add(struct fscache_object *obj)
  43 {
  44         struct fscache_object *xobj;
  45         struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
  46
  47         ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
  48
  49         write_lock(&fscache_object_list_lock);
  50
  51         while (*p) {
  52                 parent = *p;
  53                 xobj = rb_entry(parent, struct fscache_object, objlist_link);
  54
  55                 if (obj < xobj)
  56                         p = &(*p)->rb_left;
  57                 else if (obj > xobj)
  58                         p = &(*p)->rb_right;
  59                 else
  60                         BUG();
  61         }
  62
  63         rb_link_node(&obj->objlist_link, parent, p);
  64         rb_insert_color(&obj->objlist_link, &fscache_object_list);
  65
  66         write_unlock(&fscache_object_list_lock);
  67 }
  68
  69 /*
  70  * Remove an object from the object list.
  71  */
  72 void fscache_objlist_remove(struct fscache_object *obj)
  73 {
  74         if (RB_EMPTY_NODE(&obj->objlist_link))
  75                 return;
  76
  77         write_lock(&fscache_object_list_lock);
  78
  79         BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
  80         rb_erase(&obj->objlist_link, &fscache_object_list);
  81
  82         write_unlock(&fscache_object_list_lock);
  83 }
  84
  85 /*
  86  * find the object in the tree on or after the specified index
  87  */
  88 static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
  89 {
  90         struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
  91         struct rb_node *p;
  92         unsigned long pos;
  93
  94         if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
  95                 return NULL;
  96         pos = *_pos;
  97
  98         /* banners (can't represent line 0 by pos 0 as that would involve
  99          * returning a NULL pointer) */
 100         if (pos == 0)
 101                 return (struct fscache_object *)(long)++(*_pos);
 102         if (pos < 3)
 103                 return (struct fscache_object *)pos;
 104
 105         pobj = (struct fscache_object *)pos;
 106         p = fscache_object_list.rb_node;
 107         while (p) {
 108                 obj = rb_entry(p, struct fscache_object, objlist_link);
 109                 if (pobj < obj) {
 110                         if (!minobj || minobj > obj)
 111                                 minobj = obj;
 112                         p = p->rb_left;
 113                 } else if (pobj > obj) {
 114                         p = p->rb_right;
 115                 } else {
 116                         minobj = obj;
 117                         break;
 118                 }
 119                 obj = NULL;
 120         }
 121
 122         if (!minobj)
 123                 *_pos = (unsigned long) ERR_PTR(-ENOENT);
 124         else if (minobj != obj)
 125                 *_pos = (unsigned long) minobj;
 126         return minobj;
 127 }
 128
 129 /*
 130  * set up the iterator to start reading from the first line
 131  */
 132 static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
 133         __acquires(&fscache_object_list_lock)
 134 {
 135         read_lock(&fscache_object_list_lock);
 136         return fscache_objlist_lookup(_pos);
 137 }
 138
 139 /*
 140  * move to the next line
 141  */
 142 static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
 143 {
 144         (*_pos)++;
 145         return fscache_objlist_lookup(_pos);
 146 }
 147
 148 /*
 149  * clean up after reading
 150  */
 151 static void fscache_objlist_stop(struct seq_file *m, void *v)
 152         __releases(&fscache_object_list_lock)
 153 {
 154         read_unlock(&fscache_object_list_lock);
 155 }
 156
 157 /*
 158  * display an object
 159  */
 160 static int fscache_objlist_show(struct seq_file *m, void *v)
 161 {
 162         struct fscache_objlist_data *data = m->private;
 163         struct fscache_object *obj = v;
 164         struct fscache_cookie *cookie;
 165         unsigned long config = data->config;
 166         char _type[3], *type;
 167         u8 *p;
 168
 169         if ((unsigned long) v == 1) {
 170                 seq_puts(m, "OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS"
 171                          " EM EV FL S"
 172                          " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
 173                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
 174                               FSCACHE_OBJLIST_CONFIG_AUX))
 175                         seq_puts(m, "       ");
 176                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 177                         seq_puts(m, "OBJECT_KEY");
 178                 if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
 179                                FSCACHE_OBJLIST_CONFIG_AUX)) ==
 180                     (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
 181                         seq_puts(m, ", ");
 182                 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
 183                         seq_puts(m, "AUX_DATA");
 184                 seq_puts(m, "\n");
 185                 return 0;
 186         }
 187
 188         if ((unsigned long) v == 2) {
 189                 seq_puts(m, "======== ======== ==== ===== === === === == ====="
 190                          " == == == ="
 191                          " | ================ == == ================");
 192                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
 193                               FSCACHE_OBJLIST_CONFIG_AUX))
 194                         seq_puts(m, " ================");
 195                 seq_puts(m, "\n");
 196                 return 0;
 197         }
 198
 199         /* filter out any unwanted objects */
 200 #define FILTER(criterion, _yes, _no)                                    \
 201         do {                                                            \
 202                 unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes;      \
 203                 unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no;        \
 204                 if (criterion) {                                        \
 205                         if (!(config & yes))                            \
 206                                 return 0;                               \
 207                 } else {                                                \
 208                         if (!(config & no))                             \
 209                                 return 0;                               \
 210                 }                                                       \
 211         } while(0)
 212
 213         cookie = obj->cookie;
 214         if (~config) {
 215                 FILTER(cookie->def,
 216                        COOKIE, NOCOOKIE);
 217                 FILTER(fscache_object_is_active(obj) ||
 218                        obj->n_ops != 0 ||
 219                        obj->n_obj_ops != 0 ||
 220                        obj->flags ||
 221                        !list_empty(&obj->dependents),
 222                        BUSY, IDLE);
 223                 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
 224                        PENDWR, NOPENDWR);
 225                 FILTER(atomic_read(&obj->n_reads),
 226                        READS, NOREADS);
 227                 FILTER(obj->events & obj->event_mask,
 228                        EVENTS, NOEVENTS);
 229                 FILTER(work_busy(&obj->work), WORK, NOWORK);
 230         }
 231
 232         seq_printf(m,
 233                    "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
 234                    obj->debug_id,
 235                    obj->parent ? obj->parent->debug_id : -1,
 236                    obj->state->short_name,
 237                    obj->n_children,
 238                    obj->n_ops,
 239                    obj->n_obj_ops,
 240                    obj->n_in_progress,
 241                    obj->n_exclusive,
 242                    atomic_read(&obj->n_reads),
 243                    obj->event_mask,
 244                    obj->events,
 245                    obj->flags,
 246                    work_busy(&obj->work));
 247
 248         if (fscache_use_cookie(obj)) {
 249                 uint16_t keylen = 0, auxlen = 0;
 250
 251                 switch (cookie->type) {
 252                 case 0:
 253                         type = "IX";
 254                         break;
 255                 case 1:
 256                         type = "DT";
 257                         break;
 258                 default:
 259                         snprintf(_type, sizeof(_type), "%02u",
 260                                  cookie->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 (config & FSCACHE_OBJLIST_CONFIG_KEY)
 272                         keylen = cookie->key_len;
 273
 274                 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
 275                         auxlen = cookie->aux_len;
 276
 277                 if (keylen > 0 || auxlen > 0) {
 278                         seq_puts(m, " ");
 279                         p = keylen <= sizeof(cookie->inline_key) ?
 280                                 cookie->inline_key : cookie->key;
 281                         for (; keylen > 0; keylen--)
 282                                 seq_printf(m, "%02x", *p++);
 283                         if (auxlen > 0) {
 284                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
 285                                         seq_puts(m, ", ");
 286                                 p = auxlen <= sizeof(cookie->inline_aux) ?
 287                                         cookie->inline_aux : cookie->aux;
 288                                 for (; auxlen > 0; auxlen--)
 289                                         seq_printf(m, "%02x", *p++);
 290                         }
 291                 }
 292
 293                 seq_puts(m, "\n");
 294                 fscache_unuse_cookie(obj);
 295         } else {
 296                 seq_puts(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         const 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 = user_key_payload_rcu(key);
 328         if (!confkey) {
 329                 /* key was revoked */
 330                 rcu_read_unlock();
 331                 key_put(key);
 332                 goto no_config;
 333         }
 334
 335         buf = confkey->data;
 336
 337         for (len = confkey->datalen - 1; len >= 0; len--) {
 338                 switch (buf[len]) {
 339                 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;         break;
 340                 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;         break;
 341                 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;      break;
 342                 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;    break;
 343                 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;        break;
 344                 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;        break;
 345                 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;      break;
 346                 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;    break;
 347                 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;       break;
 348                 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;     break;
 349                 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;        break;
 350                 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;      break;
 351                 }
 352         }
 353
 354         rcu_read_unlock();
 355         key_put(key);
 356
 357         if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
 358             config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
 359         if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
 360             config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
 361         if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
 362             config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
 363         if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
 364             config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
 365         if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
 366             config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
 367         if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
 368             config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
 369
 370         data->config = config;
 371         return;
 372
 373 no_config:
 374 #endif
 375         data->config = ULONG_MAX;
 376 }
 377
 378 /*
 379  * open "/proc/fs/fscache/objects" to provide a list of active objects
 380  * - can be configured by a user-defined key added to the caller's keyrings
 381  */
 382 static int fscache_objlist_open(struct inode *inode, struct file *file)
 383 {
 384         struct fscache_objlist_data *data;
 385
 386         data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
 387         if (!data)
 388                 return -ENOMEM;
 389
 390         /* get the configuration key */
 391         fscache_objlist_config(data);
 392
 393         return 0;
 394 }
 395
 396 /*
 397  * clean up on close
 398  */
 399 static int fscache_objlist_release(struct inode *inode, struct file *file)
 400 {
 401         struct seq_file *m = file->private_data;
 402
 403         kfree(m->private);
 404         m->private = NULL;
 405         return seq_release(inode, file);
 406 }
 407
 408 const struct file_operations fscache_objlist_fops = {
 409         .open           = fscache_objlist_open,
 410         .read           = seq_read,
 411         .llseek         = seq_lseek,
 412         .release        = fscache_objlist_release,
 413 };