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);
  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,{%x:%u.%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
 131         return inode->i_ino == data->fid.vnode &&
 132                 inode->i_generation == data->fid.unique;
 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         inode->i_ino = data->fid.vnode;
 154         inode->i_generation = data->fid.unique;
 155         vnode->fid = data->fid;
 156         vnode->volume = data->volume;
 157
 158         return 0;
 159 }
 160
 161 /*
 162  * Create an inode for a dynamic root directory or an autocell dynamic
 163  * automount dir.
 164  */
 165 struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
 166 {
 167         struct afs_iget_data data;
 168         struct afs_super_info *as;
 169         struct afs_vnode *vnode;
 170         struct inode *inode;
 171         static atomic_t afs_autocell_ino;
 172
 173         _enter("");
 174
 175         as = sb->s_fs_info;
 176         if (as->volume) {
 177                 data.volume = as->volume;
 178                 data.fid.vid = as->volume->vid;
 179         }
 180         if (root) {
 181                 data.fid.vnode = 1;
 182                 data.fid.unique = 1;
 183         } else {
 184                 data.fid.vnode = atomic_inc_return(&afs_autocell_ino);
 185                 data.fid.unique = 0;
 186         }
 187
 188         inode = iget5_locked(sb, data.fid.vnode,
 189                              afs_iget5_pseudo_dir_test, afs_iget5_set,
 190                              &data);
 191         if (!inode) {
 192                 _leave(" = -ENOMEM");
 193                 return ERR_PTR(-ENOMEM);
 194         }
 195
 196         _debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
 197                inode, inode->i_ino, data.fid.vid, data.fid.vnode,
 198                data.fid.unique);
 199
 200         vnode = AFS_FS_I(inode);
 201
 202         /* there shouldn't be an existing inode */
 203         BUG_ON(!(inode->i_state & I_NEW));
 204
 205         inode->i_size           = 0;
 206         inode->i_mode           = S_IFDIR | S_IRUGO | S_IXUGO;
 207         if (root) {
 208                 inode->i_op     = &afs_dynroot_inode_operations;
 209                 inode->i_fop    = &afs_dynroot_file_operations;
 210         } else {
 211                 inode->i_op     = &afs_autocell_inode_operations;
 212         }
 213         set_nlink(inode, 2);
 214         inode->i_uid            = GLOBAL_ROOT_UID;
 215         inode->i_gid            = GLOBAL_ROOT_GID;
 216         inode->i_ctime.tv_sec   = get_seconds();
 217         inode->i_ctime.tv_nsec  = 0;
 218         inode->i_atime          = inode->i_mtime = inode->i_ctime;
 219         inode->i_blocks         = 0;
 220         inode_set_iversion_raw(inode, 0);
 221         inode->i_generation     = 0;
 222
 223         set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
 224         if (!root) {
 225                 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
 226                 inode->i_flags |= S_AUTOMOUNT;
 227         }
 228
 229         inode->i_flags |= S_NOATIME;
 230         unlock_new_inode(inode);
 231         _leave(" = %p", inode);
 232         return inode;
 233 }
 234
 235 /*
 236  * Get a cache cookie for an inode.
 237  */
 238 static void afs_get_inode_cache(struct afs_vnode *vnode)
 239 {
 240 #ifdef CONFIG_AFS_FSCACHE
 241         struct {
 242                 u32 vnode_id;
 243                 u32 unique;
 244                 u32 vnode_id_ext[2];    /* Allow for a 96-bit key */
 245         } __packed key;
 246         struct afs_vnode_cache_aux aux;
 247
 248         if (vnode->status.type == AFS_FTYPE_DIR) {
 249                 vnode->cache = NULL;
 250                 return;
 251         }
 252
 253         key.vnode_id            = vnode->fid.vnode;
 254         key.unique              = vnode->fid.unique;
 255         key.vnode_id_ext[0]     = 0;
 256         key.vnode_id_ext[1]     = 0;
 257         aux.data_version        = vnode->status.data_version;
 258
 259         vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
 260                                               &afs_vnode_cache_index_def,
 261                                               &key, sizeof(key),
 262                                               &aux, sizeof(aux),
 263                                               vnode, vnode->status.size, true);
 264 #endif
 265 }
 266
 267 /*
 268  * inode retrieval
 269  */
 270 struct inode *afs_iget(struct super_block *sb, struct key *key,
 271                        struct afs_fid *fid, struct afs_file_status *status,
 272                        struct afs_callback *cb, struct afs_cb_interest *cbi)
 273 {
 274         struct afs_iget_data data = { .fid = *fid };
 275         struct afs_super_info *as;
 276         struct afs_vnode *vnode;
 277         struct inode *inode;
 278         int ret;
 279
 280         _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
 281
 282         as = sb->s_fs_info;
 283         data.volume = as->volume;
 284
 285         inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
 286                              &data);
 287         if (!inode) {
 288                 _leave(" = -ENOMEM");
 289                 return ERR_PTR(-ENOMEM);
 290         }
 291
 292         _debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
 293                inode, fid->vid, fid->vnode, fid->unique);
 294
 295         vnode = AFS_FS_I(inode);
 296
 297         /* deal with an existing inode */
 298         if (!(inode->i_state & I_NEW)) {
 299                 _leave(" = %p", inode);
 300                 return inode;
 301         }
 302
 303         if (!status) {
 304                 /* it's a remotely extant inode */
 305                 ret = afs_fetch_status(vnode, key, true);
 306                 if (ret < 0)
 307                         goto bad_inode;
 308         } else {
 309                 /* it's an inode we just created */
 310                 memcpy(&vnode->status, status, sizeof(vnode->status));
 311
 312                 if (!cb) {
 313                         /* it's a symlink we just created (the fileserver
 314                          * didn't give us a callback) */
 315                         vnode->cb_version = 0;
 316                         vnode->cb_type = 0;
 317                         vnode->cb_expires_at = 0;
 318                 } else {
 319                         vnode->cb_version = cb->version;
 320                         vnode->cb_type = cb->type;
 321                         vnode->cb_expires_at = cb->expiry;
 322                         vnode->cb_interest = afs_get_cb_interest(cbi);
 323                         set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
 324                 }
 325
 326                 vnode->cb_expires_at += ktime_get_real_seconds();
 327         }
 328
 329         ret = afs_inode_init_from_status(vnode, key);
 330         if (ret < 0)
 331                 goto bad_inode;
 332
 333         afs_get_inode_cache(vnode);
 334
 335         /* success */
 336         clear_bit(AFS_VNODE_UNSET, &vnode->flags);
 337         inode->i_flags |= S_NOATIME;
 338         unlock_new_inode(inode);
 339         _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
 340         return inode;
 341
 342         /* failure */
 343 bad_inode:
 344         iget_failed(inode);
 345         _leave(" = %d [bad]", ret);
 346         return ERR_PTR(ret);
 347 }
 348
 349 /*
 350  * mark the data attached to an inode as obsolete due to a write on the server
 351  * - might also want to ditch all the outstanding writes and dirty pages
 352  */
 353 void afs_zap_data(struct afs_vnode *vnode)
 354 {
 355         _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
 356
 357 #ifdef CONFIG_AFS_FSCACHE
 358         fscache_invalidate(vnode->cache);
 359 #endif
 360
 361         /* nuke all the non-dirty pages that aren't locked, mapped or being
 362          * written back in a regular file and completely discard the pages in a
 363          * directory or symlink */
 364         if (S_ISREG(vnode->vfs_inode.i_mode))
 365                 invalidate_remote_inode(&vnode->vfs_inode);
 366         else
 367                 invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
 368 }
 369
 370 /*
 371  * validate a vnode/inode
 372  * - there are several things we need to check
 373  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
 374  *     symlink)
 375  *   - parent dir metadata changed (security changes)
 376  *   - dentry data changed (write, truncate)
 377  *   - dentry metadata changed (security changes)
 378  */
 379 int afs_validate(struct afs_vnode *vnode, struct key *key)
 380 {
 381         time64_t now = ktime_get_real_seconds();
 382         bool valid = false;
 383         int ret;
 384
 385         _enter("{v={%x:%u} fl=%lx},%x",
 386                vnode->fid.vid, vnode->fid.vnode, vnode->flags,
 387                key_serial(key));
 388
 389         /* Quickly check the callback state.  Ideally, we'd use read_seqbegin
 390          * here, but we have no way to pass the net namespace to the RCU
 391          * cleanup for the server record.
 392          */
 393         read_seqlock_excl(&vnode->cb_lock);
 394
 395         if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
 396                 if (vnode->cb_s_break != vnode->cb_interest->server->cb_s_break ||
 397                     vnode->cb_v_break != vnode->volume->cb_v_break) {
 398                         vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
 399                         vnode->cb_v_break = vnode->volume->cb_v_break;
 400                         valid = false;
 401                 } else if (vnode->status.type == AFS_FTYPE_DIR &&
 402                            test_bit(AFS_VNODE_DIR_VALID, &vnode->flags) &&
 403                            vnode->cb_expires_at - 10 > now) {
 404                         valid = true;
 405                 } else if (!test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) &&
 406                            vnode->cb_expires_at - 10 > now) {
 407                         valid = true;
 408                 }
 409         } else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 410                 valid = true;
 411         }
 412
 413         read_sequnlock_excl(&vnode->cb_lock);
 414
 415         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 416                 clear_nlink(&vnode->vfs_inode);
 417
 418         if (valid)
 419                 goto valid;
 420
 421         down_write(&vnode->validate_lock);
 422
 423         /* if the promise has expired, we need to check the server again to get
 424          * a new promise - note that if the (parent) directory's metadata was
 425          * changed then the security may be different and we may no longer have
 426          * access */
 427         if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
 428                 _debug("not promised");
 429                 ret = afs_fetch_status(vnode, key, false);
 430                 if (ret < 0) {
 431                         if (ret == -ENOENT) {
 432                                 set_bit(AFS_VNODE_DELETED, &vnode->flags);
 433                                 ret = -ESTALE;
 434                         }
 435                         goto error_unlock;
 436                 }
 437                 _debug("new promise [fl=%lx]", vnode->flags);
 438         }
 439
 440         if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 441                 _debug("file already deleted");
 442                 ret = -ESTALE;
 443                 goto error_unlock;
 444         }
 445
 446         /* if the vnode's data version number changed then its contents are
 447          * different */
 448         if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
 449                 afs_zap_data(vnode);
 450         up_write(&vnode->validate_lock);
 451 valid:
 452         _leave(" = 0");
 453         return 0;
 454
 455 error_unlock:
 456         up_write(&vnode->validate_lock);
 457         _leave(" = %d", ret);
 458         return ret;
 459 }
 460
 461 /*
 462  * read the attributes of an inode
 463  */
 464 int afs_getattr(const struct path *path, struct kstat *stat,
 465                 u32 request_mask, unsigned int query_flags)
 466 {
 467         struct inode *inode = d_inode(path->dentry);
 468         struct afs_vnode *vnode = AFS_FS_I(inode);
 469         int seq = 0;
 470
 471         _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
 472
 473         do {
 474                 read_seqbegin_or_lock(&vnode->cb_lock, &seq);
 475                 generic_fillattr(inode, stat);
 476         } while (need_seqretry(&vnode->cb_lock, seq));
 477
 478         done_seqretry(&vnode->cb_lock, seq);
 479         return 0;
 480 }
 481
 482 /*
 483  * discard an AFS inode
 484  */
 485 int afs_drop_inode(struct inode *inode)
 486 {
 487         _enter("");
 488
 489         if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
 490                 return generic_delete_inode(inode);
 491         else
 492                 return generic_drop_inode(inode);
 493 }
 494
 495 /*
 496  * clear an AFS inode
 497  */
 498 void afs_evict_inode(struct inode *inode)
 499 {
 500         struct afs_vnode *vnode;
 501
 502         vnode = AFS_FS_I(inode);
 503
 504         _enter("{%x:%u.%d}",
 505                vnode->fid.vid,
 506                vnode->fid.vnode,
 507                vnode->fid.unique);
 508
 509         _debug("CLEAR INODE %p", inode);
 510
 511         ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
 512
 513         truncate_inode_pages_final(&inode->i_data);
 514         clear_inode(inode);
 515
 516         if (vnode->cb_interest) {
 517                 afs_put_cb_interest(afs_i2net(inode), vnode->cb_interest);
 518                 vnode->cb_interest = NULL;
 519         }
 520
 521         while (!list_empty(&vnode->wb_keys)) {
 522                 struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
 523                                                     struct afs_wb_key, vnode_link);
 524                 list_del(&wbk->vnode_link);
 525                 afs_put_wb_key(wbk);
 526         }
 527
 528 #ifdef CONFIG_AFS_FSCACHE
 529         {
 530                 struct afs_vnode_cache_aux aux;
 531
 532                 aux.data_version = vnode->status.data_version;
 533                 fscache_relinquish_cookie(vnode->cache, &aux,
 534                                           test_bit(AFS_VNODE_DELETED, &vnode->flags));
 535                 vnode->cache = NULL;
 536         }
 537 #endif
 538
 539         afs_put_permits(rcu_access_pointer(vnode->permit_cache));
 540         _leave("");
 541 }
 542
 543 /*
 544  * set the attributes of an inode
 545  */
 546 int afs_setattr(struct dentry *dentry, struct iattr *attr)
 547 {
 548         struct afs_fs_cursor fc;
 549         struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 550         struct key *key;
 551         int ret;
 552
 553         _enter("{%x:%u},{n=%pd},%x",
 554                vnode->fid.vid, vnode->fid.vnode, dentry,
 555                attr->ia_valid);
 556
 557         if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
 558                                 ATTR_MTIME))) {
 559                 _leave(" = 0 [unsupported]");
 560                 return 0;
 561         }
 562
 563         /* flush any dirty data outstanding on a regular file */
 564         if (S_ISREG(vnode->vfs_inode.i_mode))
 565                 filemap_write_and_wait(vnode->vfs_inode.i_mapping);
 566
 567         if (attr->ia_valid & ATTR_FILE) {
 568                 key = afs_file_key(attr->ia_file);
 569         } else {
 570                 key = afs_request_key(vnode->volume->cell);
 571                 if (IS_ERR(key)) {
 572                         ret = PTR_ERR(key);
 573                         goto error;
 574                 }
 575         }
 576
 577         ret = -ERESTARTSYS;
 578         if (afs_begin_vnode_operation(&fc, vnode, key)) {
 579                 while (afs_select_fileserver(&fc)) {
 580                         fc.cb_break = afs_calc_vnode_cb_break(vnode);
 581                         afs_fs_setattr(&fc, attr);
 582                 }
 583
 584                 afs_check_for_remote_deletion(&fc, fc.vnode);
 585                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
 586                 ret = afs_end_vnode_operation(&fc);
 587         }
 588
 589         if (!(attr->ia_valid & ATTR_FILE))
 590                 key_put(key);
 591
 592 error:
 593         _leave(" = %d", ret);
 594         return ret;
 595 }