fs/afs/vnode.c

   1 /* vnode.c: AFS vnode management
   2  *
   3  * Copyright (C) 2002 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 License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/fs.h>
  17 #include <linux/pagemap.h>
  18 #include "volume.h"
  19 #include "cell.h"
  20 #include "cmservice.h"
  21 #include "fsclient.h"
  22 #include "vlclient.h"
  23 #include "vnode.h"
  24 #include "internal.h"
  25
  26 static void afs_vnode_cb_timed_out(struct afs_timer *timer);
  27
  28 struct afs_timer_ops afs_vnode_cb_timed_out_ops = {
  29         .timed_out      = afs_vnode_cb_timed_out,
  30 };
  31
  32 #ifdef AFS_CACHING_SUPPORT
  33 static cachefs_match_val_t afs_vnode_cache_match(void *target,
  34                                                  const void *entry);
  35 static void afs_vnode_cache_update(void *source, void *entry);
  36
  37 struct cachefs_index_def afs_vnode_cache_index_def = {
  38         .name           = "vnode",
  39         .data_size      = sizeof(struct afs_cache_vnode),
  40         .keys[0]        = { CACHEFS_INDEX_KEYS_BIN, 4 },
  41         .match          = afs_vnode_cache_match,
  42         .update         = afs_vnode_cache_update,
  43 };
  44 #endif
  45
  46 /*****************************************************************************/
  47 /*
  48  * handle a callback timing out
  49  * TODO: retain a ref to vnode struct for an outstanding callback timeout
  50  */
  51 static void afs_vnode_cb_timed_out(struct afs_timer *timer)
  52 {
  53         struct afs_server *oldserver;
  54         struct afs_vnode *vnode;
  55
  56         vnode = list_entry(timer, struct afs_vnode, cb_timeout);
  57
  58         _enter("%p", vnode);
  59
  60         /* set the changed flag in the vnode and release the server */
  61         spin_lock(&vnode->lock);
  62
  63         oldserver = xchg(&vnode->cb_server, NULL);
  64         if (oldserver) {
  65                 vnode->flags |= AFS_VNODE_CHANGED;
  66
  67                 spin_lock(&afs_cb_hash_lock);
  68                 list_del_init(&vnode->cb_hash_link);
  69                 spin_unlock(&afs_cb_hash_lock);
  70
  71                 spin_lock(&oldserver->cb_lock);
  72                 list_del_init(&vnode->cb_link);
  73                 spin_unlock(&oldserver->cb_lock);
  74         }
  75
  76         spin_unlock(&vnode->lock);
  77
  78         afs_put_server(oldserver);
  79
  80         _leave("");
  81 } /* end afs_vnode_cb_timed_out() */
  82
  83 /*****************************************************************************/
  84 /*
  85  * finish off updating the recorded status of a file
  86  * - starts callback expiry timer
  87  * - adds to server's callback list
  88  */
  89 static void afs_vnode_finalise_status_update(struct afs_vnode *vnode,
  90                                              struct afs_server *server,
  91                                              int ret)
  92 {
  93         struct afs_server *oldserver = NULL;
  94
  95         _enter("%p,%p,%d", vnode, server, ret);
  96
  97         spin_lock(&vnode->lock);
  98
  99         vnode->flags &= ~AFS_VNODE_CHANGED;
 100
 101         if (ret == 0) {
 102                 /* adjust the callback timeout appropriately */
 103                 afs_kafstimod_add_timer(&vnode->cb_timeout,
 104                                         vnode->cb_expiry * HZ);
 105
 106                 spin_lock(&afs_cb_hash_lock);
 107                 list_move_tail(&vnode->cb_hash_link,
 108                               &afs_cb_hash(server, &vnode->fid));
 109                 spin_unlock(&afs_cb_hash_lock);
 110
 111                 /* swap ref to old callback server with that for new callback
 112                  * server */
 113                 oldserver = xchg(&vnode->cb_server, server);
 114                 if (oldserver != server) {
 115                         if (oldserver) {
 116                                 spin_lock(&oldserver->cb_lock);
 117                                 list_del_init(&vnode->cb_link);
 118                                 spin_unlock(&oldserver->cb_lock);
 119                         }
 120
 121                         afs_get_server(server);
 122                         spin_lock(&server->cb_lock);
 123                         list_add_tail(&vnode->cb_link, &server->cb_promises);
 124                         spin_unlock(&server->cb_lock);
 125                 }
 126                 else {
 127                         /* same server */
 128                         oldserver = NULL;
 129                 }
 130         }
 131         else if (ret == -ENOENT) {
 132                 /* the file was deleted - clear the callback timeout */
 133                 oldserver = xchg(&vnode->cb_server, NULL);
 134                 afs_kafstimod_del_timer(&vnode->cb_timeout);
 135
 136                 _debug("got NOENT from server - marking file deleted");
 137                 vnode->flags |= AFS_VNODE_DELETED;
 138         }
 139
 140         vnode->update_cnt--;
 141
 142         spin_unlock(&vnode->lock);
 143
 144         wake_up_all(&vnode->update_waitq);
 145
 146         afs_put_server(oldserver);
 147
 148         _leave("");
 149
 150 } /* end afs_vnode_finalise_status_update() */
 151
 152 /*****************************************************************************/
 153 /*
 154  * fetch file status from the volume
 155  * - don't issue a fetch if:
 156  *   - the changed bit is not set and there's a valid callback
 157  *   - there are any outstanding ops that will fetch the status
 158  * - TODO implement local caching
 159  */
 160 int afs_vnode_fetch_status(struct afs_vnode *vnode)
 161 {
 162         struct afs_server *server;
 163         int ret;
 164
 165         DECLARE_WAITQUEUE(myself, current);
 166
 167         _enter("%s,{%u,%u,%u}",
 168                vnode->volume->vlocation->vldb.name,
 169                vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
 170
 171         if (!(vnode->flags & AFS_VNODE_CHANGED) && vnode->cb_server) {
 172                 _leave(" [unchanged]");
 173                 return 0;
 174         }
 175
 176         if (vnode->flags & AFS_VNODE_DELETED) {
 177                 _leave(" [deleted]");
 178                 return -ENOENT;
 179         }
 180
 181         spin_lock(&vnode->lock);
 182
 183         if (!(vnode->flags & AFS_VNODE_CHANGED)) {
 184                 spin_unlock(&vnode->lock);
 185                 _leave(" [unchanged]");
 186                 return 0;
 187         }
 188
 189         if (vnode->update_cnt > 0) {
 190                 /* someone else started a fetch */
 191                 set_current_state(TASK_UNINTERRUPTIBLE);
 192                 add_wait_queue(&vnode->update_waitq, &myself);
 193
 194                 /* wait for the status to be updated */
 195                 for (;;) {
 196                         if (!(vnode->flags & AFS_VNODE_CHANGED))
 197                                 break;
 198                         if (vnode->flags & AFS_VNODE_DELETED)
 199                                 break;
 200
 201                         /* it got updated and invalidated all before we saw
 202                          * it */
 203                         if (vnode->update_cnt == 0) {
 204                                 remove_wait_queue(&vnode->update_waitq,
 205                                                   &myself);
 206                                 set_current_state(TASK_RUNNING);
 207                                 goto get_anyway;
 208                         }
 209
 210                         spin_unlock(&vnode->lock);
 211
 212                         schedule();
 213                         set_current_state(TASK_UNINTERRUPTIBLE);
 214
 215                         spin_lock(&vnode->lock);
 216                 }
 217
 218                 remove_wait_queue(&vnode->update_waitq, &myself);
 219                 spin_unlock(&vnode->lock);
 220                 set_current_state(TASK_RUNNING);
 221
 222                 return vnode->flags & AFS_VNODE_DELETED ? -ENOENT : 0;
 223         }
 224
 225  get_anyway:
 226         /* okay... we're going to have to initiate the op */
 227         vnode->update_cnt++;
 228
 229         spin_unlock(&vnode->lock);
 230
 231         /* merge AFS status fetches and clear outstanding callback on this
 232          * vnode */
 233         do {
 234                 /* pick a server to query */
 235                 ret = afs_volume_pick_fileserver(vnode->volume, &server);
 236                 if (ret<0)
 237                         return ret;
 238
 239                 _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
 240
 241                 ret = afs_rxfs_fetch_file_status(server, vnode, NULL);
 242
 243         } while (!afs_volume_release_fileserver(vnode->volume, server, ret));
 244
 245         /* adjust the flags */
 246         afs_vnode_finalise_status_update(vnode, server, ret);
 247
 248         _leave(" = %d", ret);
 249         return ret;
 250 } /* end afs_vnode_fetch_status() */
 251
 252 /*****************************************************************************/
 253 /*
 254  * fetch file data from the volume
 255  * - TODO implement caching and server failover
 256  */
 257 int afs_vnode_fetch_data(struct afs_vnode *vnode,
 258                          struct afs_rxfs_fetch_descriptor *desc)
 259 {
 260         struct afs_server *server;
 261         int ret;
 262
 263         _enter("%s,{%u,%u,%u}",
 264                vnode->volume->vlocation->vldb.name,
 265                vnode->fid.vid,
 266                vnode->fid.vnode,
 267                vnode->fid.unique);
 268
 269         /* this op will fetch the status */
 270         spin_lock(&vnode->lock);
 271         vnode->update_cnt++;
 272         spin_unlock(&vnode->lock);
 273
 274         /* merge in AFS status fetches and clear outstanding callback on this
 275          * vnode */
 276         do {
 277                 /* pick a server to query */
 278                 ret = afs_volume_pick_fileserver(vnode->volume, &server);
 279                 if (ret < 0)
 280                         return ret;
 281
 282                 _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
 283
 284                 ret = afs_rxfs_fetch_file_data(server, vnode, desc, NULL);
 285
 286         } while (!afs_volume_release_fileserver(vnode->volume, server, ret));
 287
 288         /* adjust the flags */
 289         afs_vnode_finalise_status_update(vnode, server, ret);
 290
 291         _leave(" = %d", ret);
 292         return ret;
 293
 294 } /* end afs_vnode_fetch_data() */
 295
 296 /*****************************************************************************/
 297 /*
 298  * break any outstanding callback on a vnode
 299  * - only relevent to server that issued it
 300  */
 301 int afs_vnode_give_up_callback(struct afs_vnode *vnode)
 302 {
 303         struct afs_server *server;
 304         int ret;
 305
 306         _enter("%s,{%u,%u,%u}",
 307                vnode->volume->vlocation->vldb.name,
 308                vnode->fid.vid,
 309                vnode->fid.vnode,
 310                vnode->fid.unique);
 311
 312         spin_lock(&afs_cb_hash_lock);
 313         list_del_init(&vnode->cb_hash_link);
 314         spin_unlock(&afs_cb_hash_lock);
 315
 316         /* set the changed flag in the vnode and release the server */
 317         spin_lock(&vnode->lock);
 318
 319         afs_kafstimod_del_timer(&vnode->cb_timeout);
 320
 321         server = xchg(&vnode->cb_server, NULL);
 322         if (server) {
 323                 vnode->flags |= AFS_VNODE_CHANGED;
 324
 325                 spin_lock(&server->cb_lock);
 326                 list_del_init(&vnode->cb_link);
 327                 spin_unlock(&server->cb_lock);
 328         }
 329
 330         spin_unlock(&vnode->lock);
 331
 332         ret = 0;
 333         if (server) {
 334                 ret = afs_rxfs_give_up_callback(server, vnode);
 335                 afs_put_server(server);
 336         }
 337
 338         _leave(" = %d", ret);
 339         return ret;
 340 } /* end afs_vnode_give_up_callback() */
 341
 342 /*****************************************************************************/
 343 /*
 344  * match a vnode record stored in the cache
 345  */
 346 #ifdef AFS_CACHING_SUPPORT
 347 static cachefs_match_val_t afs_vnode_cache_match(void *target,
 348                                                  const void *entry)
 349 {
 350         const struct afs_cache_vnode *cvnode = entry;
 351         struct afs_vnode *vnode = target;
 352
 353         _enter("{%x,%x,%Lx},{%x,%x,%Lx}",
 354                vnode->fid.vnode,
 355                vnode->fid.unique,
 356                vnode->status.version,
 357                cvnode->vnode_id,
 358                cvnode->vnode_unique,
 359                cvnode->data_version);
 360
 361         if (vnode->fid.vnode != cvnode->vnode_id) {
 362                 _leave(" = FAILED");
 363                 return CACHEFS_MATCH_FAILED;
 364         }
 365
 366         if (vnode->fid.unique != cvnode->vnode_unique ||
 367             vnode->status.version != cvnode->data_version) {
 368                 _leave(" = DELETE");
 369                 return CACHEFS_MATCH_SUCCESS_DELETE;
 370         }
 371
 372         _leave(" = SUCCESS");
 373         return CACHEFS_MATCH_SUCCESS;
 374 } /* end afs_vnode_cache_match() */
 375 #endif
 376
 377 /*****************************************************************************/
 378 /*
 379  * update a vnode record stored in the cache
 380  */
 381 #ifdef AFS_CACHING_SUPPORT
 382 static void afs_vnode_cache_update(void *source, void *entry)
 383 {
 384         struct afs_cache_vnode *cvnode = entry;
 385         struct afs_vnode *vnode = source;
 386
 387         _enter("");
 388
 389         cvnode->vnode_id        = vnode->fid.vnode;
 390         cvnode->vnode_unique    = vnode->fid.unique;
 391         cvnode->data_version    = vnode->status.version;
 392
 393 } /* end afs_vnode_cache_update() */
 394 #endif