fs/afs/inode.c

   1 /*
   2  * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
   3  *
   4  * This software may be freely redistributed under the terms of the
   5  * GNU General Public License.
   6  *
   7  * You should have received a copy of the GNU General Public License
   8  * along with this program; if not, write to the Free Software
   9  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  10  *
  11  * Authors: David Woodhouse <dwmw2@infradead.org>
  12  *          David Howells <dhowells@redhat.com>
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/fs.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/sched.h>
  22 #include <linux/mount.h>
  23 #include <linux/namei.h>
  24 #include <linux/iversion.h>
  25 #include "internal.h"
  26
  27 static const struct inode_operations afs_symlink_inode_operations = {
  28         .get_link       = page_get_link,
  29         .listxattr      = afs_listxattr,
  30 };
  31
  32 /*
  33  * Initialise an inode from the vnode status.
  34  */
  35 static int afs_inode_init_from_status(struct afs_vnode *vnode, struct key *key)
  36 {
  37         struct inode *inode = AFS_VNODE_TO_I(vnode);
  38
  39         _debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
  40                vnode->status.type,
  41                vnode->status.nlink,
  42                (unsigned long long) vnode->status.size,
  43                vnode->status.data_version,
  44                vnode->status.mode);
  45
  46         read_seqlock_excl(&vnode->cb_lock);
  47
  48         afs_update_inode_from_status(vnode, &vnode->status, NULL,
  49                                      AFS_VNODE_NOT_YET_SET);
  50
  51         switch (vnode->status.type) {
  52         case AFS_FTYPE_FILE:
  53                 inode->i_mode   = S_IFREG | vnode->status.mode;
  54                 inode->i_op     = &afs_file_inode_operations;
  55                 inode->i_fop    = &afs_file_operations;
  56                 inode->i_mapping->a_ops = &afs_fs_aops;
  57                 break;
  58         case AFS_FTYPE_DIR:
  59                 inode->i_mode   = S_IFDIR | vnode->status.mode;
  60                 inode->i_op     = &afs_dir_inode_operations;
  61                 inode->i_fop    = &afs_dir_file_operations;
  62                 inode->i_mapping->a_ops = &afs_dir_aops;
  63                 break;
  64         case AFS_FTYPE_SYMLINK:
  65                 /* Symlinks with a mode of 0644 are actually mountpoints. */
  66                 if ((vnode->status.mode & 0777) == 0644) {
  67                         inode->i_flags |= S_AUTOMOUNT;
  68
  69                         set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
  70
  71                         inode->i_mode   = S_IFDIR | 0555;
  72                         inode->i_op     = &afs_mntpt_inode_operations;
  73                         inode->i_fop    = &afs_mntpt_file_operations;
  74                         inode->i_mapping->a_ops = &afs_fs_aops;
  75                 } else {
  76                         inode->i_mode   = S_IFLNK | vnode->status.mode;
  77                         inode->i_op     = &afs_symlink_inode_operations;
  78                         inode->i_mapping->a_ops = &afs_fs_aops;
  79                 }
  80                 inode_nohighmem(inode);
  81                 break;
  82         default:
  83                 printk("kAFS: AFS vnode with undefined type\n");
  84                 read_sequnlock_excl(&vnode->cb_lock);
  85                 return afs_protocol_error(NULL, -EBADMSG, afs_eproto_file_type);
  86         }
  87
  88         inode->i_blocks         = 0;
  89         vnode->invalid_before   = vnode->status.data_version;
  90
  91         read_sequnlock_excl(&vnode->cb_lock);
  92         return 0;
  93 }
  94
  95 /*
  96  * Fetch file status from the volume.
  97  */
  98 int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool new_inode)
  99 {
 100         struct afs_fs_cursor fc;
 101         int ret;
 102
 103         _enter("%s,{%llx:%llu.%u,S=%lx}",
 104                vnode->volume->name,
 105                vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
 106                vnode->flags);
 107
 108         ret = -ERESTARTSYS;
 109         if (afs_begin_vnode_operation(&fc, vnode, key)) {
 110                 while (afs_select_fileserver(&fc)) {
 111                         fc.cb_break = afs_calc_vnode_cb_break(vnode);
 112                         afs_fs_fetch_file_status(&fc, NULL, new_inode);
 113                 }
 114
 115                 afs_check_for_remote_deletion(&fc, fc.vnode);
 116                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
 117                 ret = afs_end_vnode_operation(&fc);
 118         }
 119
 120         _leave(" = %d", ret);
 121         return ret;
 122 }
 123
 124 /*
 125  * iget5() comparator
 126  */
 127 int afs_iget5_test(struct inode *inode, void *opaque)
 128 {
 129         struct afs_iget_data *data = opaque;
 130         struct afs_vnode *vnode = AFS_FS_I(inode);
 131
 132         return memcmp(&vnode->fid, &data->fid, sizeof(data->fid)) == 0;
 133 }
 134
 135 /*
 136  * iget5() comparator for inode created by autocell operations
 137  *
 138  * These pseudo inodes don't match anything.
 139  */
 140 static int afs_iget5_pseudo_dir_test(struct inode *inode, void *opaque)
 141 {
 142         return 0;
 143 }
 144
 145 /*
 146  * iget5() inode initialiser
 147  */
 148 static int afs_iget5_set(struct inode *inode, void *opaque)
 149 {
 150         struct afs_iget_data *data = opaque;
 151         struct afs_vnode *vnode = AFS_FS_I(inode);
 152
 153         vnode->fid = data->fid;
 154         vnode->volume = data->volume;
 155
 156         /* YFS supports 96-bit vnode IDs, but Linux only supports
 157          * 64-bit inode numbers.
 158          */
 159         inode->i_ino = data->fid.vnode;
 160         inode->i_generation = data->fid.unique;
 161         return 0;
 162 }
 163
 164 /*
 165  * Create an inode for a dynamic root directory or an autocell dynamic
 166  * automount dir.
 167  */
 168 struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
 169 {
 170         struct afs_iget_data data;
 171         struct afs_super_info *as;
 172         struct afs_vnode *vnode;
 173         struct inode *inode;
 174         static atomic_t afs_autocell_ino;
 175
 176         _enter("");
 177
 178         as = sb->s_fs_info;
 179         if (as->volume) {
 180                 data.volume = as->volume;
 181                 data.fid.vid = as->volume->vid;
 182         }
 183         if (root) {
 184                 data.fid.vnode = 1;
 185                 data.fid.unique = 1;
 186         } else {
 187                 data.fid.vnode = atomic_inc_return(&afs_autocell_ino);
 188                 data.fid.unique = 0;
 189         }
 190
 191         inode = iget5_locked(sb, data.fid.vnode,
 192                              afs_iget5_pseudo_dir_test, afs_iget5_set,
 193                              &data);
 194         if (!inode) {
 195                 _leave(" = -ENOMEM");
 196                 return ERR_PTR(-ENOMEM);
 197         }
 198
 199         _debug("GOT INODE %p { ino=%lu, vl=%llx, vn=%llx, u=%x }",
 200                inode, inode->i_ino, data.fid.vid, data.fid.vnode,
 201                data.fid.unique);
 202
 203         vnode = AFS_FS_I(inode);
 204
 205         /* there shouldn't be an existing inode */
 206         BUG_ON(!(inode->i_state & I_NEW));
 207
 208         inode->i_size           = 0;
 209         inode->i_mode           = S_IFDIR | S_IRUGO | S_IXUGO;
 210         if (root) {
 211                 inode->i_op     = &afs_dynroot_inode_operations;
 212                 inode->i_fop    = &afs_dynroot_file_operations;
 213         } else {
 214                 inode->i_op     = &afs_autocell_inode_operations;
 215         }
 216         set_nlink(inode, 2);
 217         inode->i_uid            = GLOBAL_ROOT_UID;
 218         inode->i_gid            = GLOBAL_ROOT_GID;
 219         inode->i_ctime.tv_sec   = get_seconds();
 220         inode->i_ctime.tv_nsec  = 0;
 221         inode->i_atime          = inode->i_mtime = inode->i_ctime;
 222         inode->i_blocks         = 0;
 223         inode_set_iversion_raw(inode, 0);
 224         inode->i_generation     = 0;
 225
 226         set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
 227         if (!root) {
 228                 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
 229                 inode->i_flags |= S_AUTOMOUNT;
 230         }
 231
 232         inode->i_flags |= S_NOATIME;
 233         unlock_new_inode(inode);
 234         _leave(" = %p", inode);
 235         return inode;
 236 }
 237
 238 /*
 239  * Get a cache cookie for an inode.
 240  */
 241 static void afs_get_inode_cache(struct afs_vnode *vnode)
 242 {
 243 #ifdef CONFIG_AFS_FSCACHE
 244         struct {
 245                 u32 vnode_id;
 246                 u32 unique;
 247                 u32 vnode_id_ext[2];    /* Allow for a 96-bit key */
 248         } __packed key;
 249         struct afs_vnode_cache_aux aux;
 250
 251         if (vnode->status.type == AFS_FTYPE_DIR) {
 252                 vnode->cache = NULL;
 253                 return;
 254         }
 255
 256         key.vnode_id            = vnode->fid.vnode;
 257         key.unique              = vnode->fid.unique;
 258         key.vnode_id_ext[0]     = vnode->fid.vnode >> 32;
 259         key.vnode_id_ext[1]     = vnode->fid.vnode_hi;
 260         aux.data_version        = vnode->status.data_version;
 261
 262         vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
 263                                               &afs_vnode_cache_index_def,
 264                                               &key, sizeof(key),
 265                                               &aux, sizeof(aux),
 266                                               vnode, vnode->status.size, true);
 267 #endif
 268 }
 269
 270 /*
 271  * inode retrieval
 272  */
 273 struct inode *afs_iget(struct super_block *sb, struct key *key,
 274                        struct afs_fid *fid, struct afs_file_status *status,
 275                        struct afs_callback *cb, struct afs_cb_interest *cbi)
 276 {
 277         struct afs_iget_data data = { .fid = *fid };
 278         struct afs_super_info *as;
 279         struct afs_vnode *vnode;
 280         struct inode *inode;
 281         int ret;
 282
 283         _enter(",{%llx:%llu.%u},,", fid->vid, fid->vnode, fid->unique);
 284
 285         as = sb->s_fs_info;
 286         data.volume = as->volume;
 287
 288         inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
 289                              &data);
 290         if (!inode) {
 291                 _leave(" = -ENOMEM");
 292                 return ERR_PTR(-ENOMEM);
 293         }
 294
 295         _debug("GOT INODE %p { vl=%llx vn=%llx, u=%x }",
 296                inode, fid->vid, fid->vnode, fid->unique);
 297
 298         vnode = AFS_FS_I(inode);
 299
 300         /* deal with an existing inode */
 301         if (!(inode->i_state & I_NEW)) {
 302                 _leave(" = %p", inode);
 303                 return inode;
 304         }
 305
 306         if (!status) {
 307                 /* it's a remotely extant inode */
 308                 ret = afs_fetch_status(vnode, key, true);
 309                 if (ret < 0)
 310                         goto bad_inode;
 311         } else {
 312                 /* it's an inode we just created */
 313                 memcpy(&vnode->status, status, sizeof(vnode->status));
 314
 315                 if (!cb) {
 316                         /* it's a symlink we just created (the fileserver
 317                          * didn't give us a callback) */
 318                         vnode->cb_version = 0;
 319                         vnode->cb_type = 0;
 320                         vnode->cb_expires_at = ktime_get();
 321                 } else {
 322                         vnode->cb_version = cb->version;
 323                         vnode->cb_type = cb->type;
 324                         vnode->cb_expires_at = cb->expires_at;
 325                         vnode->cb_interest = afs_get_cb_interest(cbi);
 326                         set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
 327                 }
 328
 329                 vnode->cb_expires_at += ktime_get_real_seconds();
 330         }
 331
 332         ret = afs_inode_init_from_status(vnode, key);
 333         if (ret < 0)
 334                 goto bad_inode;
 335
 336         afs_get_inode_cache(vnode);
 337
 338         /* success */
 339         clear_bit(AFS_VNODE_UNSET, &vnode->flags);
 340         inode->i_flags |= S_NOATIME;
 341         unlock_new_inode(inode);
 342         _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
 343         return inode;
 344
 345         /* failure */
 346 bad_inode:
 347         iget_failed(inode);
 348         _leave(" = %d [bad]", ret);
 349         return ERR_PTR(ret);
 350 }
 351
 352 /*
 353  * mark the data attached to an inode as obsolete due to a write on the server
 354  * - might also want to ditch all the outstanding writes and dirty pages
 355  */
 356 void afs_zap_data(struct afs_vnode *vnode)
 357 {
 358         _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
 359
 360 #ifdef CONFIG_AFS_FSCACHE
 361         fscache_invalidate(vnode->cache);
 362 #endif
 363
 364         /* nuke all the non-dirty pages that aren't locked, mapped or being
 365          * written back in a regular file and completely discard the pages in a
 366          * directory or symlink */
 367         if (S_ISREG(vnode->vfs_inode.i_mode))
 368                 invalidate_remote_inode(&vnode->vfs_inode);
 369         else
 370                 invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
 371 }
 372
 373 /*
 374  * validate a vnode/inode
 375  * - there are several things we need to check
 376  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
 377  *     symlink)
 378  *   - parent dir metadata changed (security changes)
 379  *   - dentry data changed (write, truncate)
 380  *   - dentry metadata changed (security changes)
 381  */
 382 int afs_validate(struct afs_vnode *vnode, struct key *key)
 383 {
 384         time64_t now = ktime_get_real_seconds();
 385         bool valid;
 386         int ret;
 387
 388         _enter("{v={%llx:%llu} fl=%lx},%x",
 389                vnode->fid.vid, vnode->fid.vnode, vnode->flags,
 390                key_serial(key));
 391
 392         /* Quickly check the callback state.  Ideally, we'd use read_seqbegin
 393          * here, but we have no way to pass the net namespace to the RCU
 394          * cleanup for the server record.
 395          */
 396         read_seqlock_excl(&vnode->cb_lock);
 397
 398         if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
 399                 if (vnode->cb_s_break != vnode->cb_interest->server->cb_s_break ||
 400                     vnode->cb_v_break != vnode->volume->cb_v_break) {
 401                         vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
 402                         vnode->cb_v_break = vnode->volume->cb_v_break;
 403                         valid = false;
 404                 } else if (vnode->status.type == AFS_FTYPE_DIR &&
 405                            (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags) ||
 406                             vnode->cb_expires_at - 10 <= now)) {
 407                         valid = false;
 408                 } else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) ||
 409                            vnode->cb_expires_at - 10 <= now) {
 410                         valid = false;
 411                 } else {
 412                         valid = true;
 413                 }
 414         } else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 415                 valid = true;
 416         } else {
 417                 vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
 418                 vnode->cb_v_break = vnode->volume->cb_v_break;
 419                 valid = false;
 420         }
 421
 422         read_sequnlock_excl(&vnode->cb_lock);
 423
 424         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 425                 clear_nlink(&vnode->vfs_inode);
 426
 427         if (valid)
 428                 goto valid;
 429
 430         down_write(&vnode->validate_lock);
 431
 432         /* if the promise has expired, we need to check the server again to get
 433          * a new promise - note that if the (parent) directory's metadata was
 434          * changed then the security may be different and we may no longer have
 435          * access */
 436         if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
 437                 _debug("not promised");
 438                 ret = afs_fetch_status(vnode, key, false);
 439                 if (ret < 0) {
 440                         if (ret == -ENOENT) {
 441                                 set_bit(AFS_VNODE_DELETED, &vnode->flags);
 442                                 ret = -ESTALE;
 443                         }
 444                         goto error_unlock;
 445                 }
 446                 _debug("new promise [fl=%lx]", vnode->flags);
 447         }
 448
 449         if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 450                 _debug("file already deleted");
 451                 ret = -ESTALE;
 452                 goto error_unlock;
 453         }
 454
 455         /* if the vnode's data version number changed then its contents are
 456          * different */
 457         if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
 458                 afs_zap_data(vnode);
 459         up_write(&vnode->validate_lock);
 460 valid:
 461         _leave(" = 0");
 462         return 0;
 463
 464 error_unlock:
 465         up_write(&vnode->validate_lock);
 466         _leave(" = %d", ret);
 467         return ret;
 468 }
 469
 470 /*
 471  * read the attributes of an inode
 472  */
 473 int afs_getattr(const struct path *path, struct kstat *stat,
 474                 u32 request_mask, unsigned int query_flags)
 475 {
 476         struct inode *inode = d_inode(path->dentry);
 477         struct afs_vnode *vnode = AFS_FS_I(inode);
 478         int seq = 0;
 479
 480         _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
 481
 482         do {
 483                 read_seqbegin_or_lock(&vnode->cb_lock, &seq);
 484                 generic_fillattr(inode, stat);
 485         } while (need_seqretry(&vnode->cb_lock, seq));
 486
 487         done_seqretry(&vnode->cb_lock, seq);
 488         return 0;
 489 }
 490
 491 /*
 492  * discard an AFS inode
 493  */
 494 int afs_drop_inode(struct inode *inode)
 495 {
 496         _enter("");
 497
 498         if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
 499                 return generic_delete_inode(inode);
 500         else
 501                 return generic_drop_inode(inode);
 502 }
 503
 504 /*
 505  * clear an AFS inode
 506  */
 507 void afs_evict_inode(struct inode *inode)
 508 {
 509         struct afs_vnode *vnode;
 510
 511         vnode = AFS_FS_I(inode);
 512
 513         _enter("{%llx:%llu.%d}",
 514                vnode->fid.vid,
 515                vnode->fid.vnode,
 516                vnode->fid.unique);
 517
 518         _debug("CLEAR INODE %p", inode);
 519
 520         ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
 521
 522         truncate_inode_pages_final(&inode->i_data);
 523         clear_inode(inode);
 524
 525         if (vnode->cb_interest) {
 526                 afs_put_cb_interest(afs_i2net(inode), vnode->cb_interest);
 527                 vnode->cb_interest = NULL;
 528         }
 529
 530         while (!list_empty(&vnode->wb_keys)) {
 531                 struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
 532                                                     struct afs_wb_key, vnode_link);
 533                 list_del(&wbk->vnode_link);
 534                 afs_put_wb_key(wbk);
 535         }
 536
 537 #ifdef CONFIG_AFS_FSCACHE
 538         {
 539                 struct afs_vnode_cache_aux aux;
 540
 541                 aux.data_version = vnode->status.data_version;
 542                 fscache_relinquish_cookie(vnode->cache, &aux,
 543                                           test_bit(AFS_VNODE_DELETED, &vnode->flags));
 544                 vnode->cache = NULL;
 545         }
 546 #endif
 547
 548         afs_put_permits(rcu_access_pointer(vnode->permit_cache));
 549         _leave("");
 550 }
 551
 552 /*
 553  * set the attributes of an inode
 554  */
 555 int afs_setattr(struct dentry *dentry, struct iattr *attr)
 556 {
 557         struct afs_fs_cursor fc;
 558         struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 559         struct key *key;
 560         int ret;
 561
 562         _enter("{%llx:%llu},{n=%pd},%x",
 563                vnode->fid.vid, vnode->fid.vnode, dentry,
 564                attr->ia_valid);
 565
 566         if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
 567                                 ATTR_MTIME))) {
 568                 _leave(" = 0 [unsupported]");
 569                 return 0;
 570         }
 571
 572         /* flush any dirty data outstanding on a regular file */
 573         if (S_ISREG(vnode->vfs_inode.i_mode))
 574                 filemap_write_and_wait(vnode->vfs_inode.i_mapping);
 575
 576         if (attr->ia_valid & ATTR_FILE) {
 577                 key = afs_file_key(attr->ia_file);
 578         } else {
 579                 key = afs_request_key(vnode->volume->cell);
 580                 if (IS_ERR(key)) {
 581                         ret = PTR_ERR(key);
 582                         goto error;
 583                 }
 584         }
 585
 586         ret = -ERESTARTSYS;
 587         if (afs_begin_vnode_operation(&fc, vnode, key)) {
 588                 while (afs_select_fileserver(&fc)) {
 589                         fc.cb_break = afs_calc_vnode_cb_break(vnode);
 590                         afs_fs_setattr(&fc, attr);
 591                 }
 592
 593                 afs_check_for_remote_deletion(&fc, fc.vnode);
 594                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
 595                 ret = afs_end_vnode_operation(&fc);
 596         }
 597
 598         if (!(attr->ia_valid & ATTR_FILE))
 599                 key_put(key);
 600
 601 error:
 602         _leave(" = %d", ret);
 603         return ret;
 604 }