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 "internal.h"
  25
  26 struct afs_iget_data {
  27         struct afs_fid          fid;
  28         struct afs_volume       *volume;        /* volume on which resides */
  29 };
  30
  31 static const struct inode_operations afs_symlink_inode_operations = {
  32         .get_link       = page_get_link,
  33         .listxattr      = afs_listxattr,
  34 };
  35
  36 /*
  37  * map the AFS file status to the inode member variables
  38  */
  39 static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
  40 {
  41         struct inode *inode = AFS_VNODE_TO_I(vnode);
  42
  43         _debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
  44                vnode->status.type,
  45                vnode->status.nlink,
  46                (unsigned long long) vnode->status.size,
  47                vnode->status.data_version,
  48                vnode->status.mode);
  49
  50         switch (vnode->status.type) {
  51         case AFS_FTYPE_FILE:
  52                 inode->i_mode   = S_IFREG | vnode->status.mode;
  53                 inode->i_op     = &afs_file_inode_operations;
  54                 inode->i_fop    = &afs_file_operations;
  55                 break;
  56         case AFS_FTYPE_DIR:
  57                 inode->i_mode   = S_IFDIR | vnode->status.mode;
  58                 inode->i_op     = &afs_dir_inode_operations;
  59                 inode->i_fop    = &afs_dir_file_operations;
  60                 break;
  61         case AFS_FTYPE_SYMLINK:
  62                 /* Symlinks with a mode of 0644 are actually mountpoints. */
  63                 if ((vnode->status.mode & 0777) == 0644) {
  64                         inode->i_flags |= S_AUTOMOUNT;
  65
  66                         spin_lock(&vnode->lock);
  67                         set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
  68                         spin_unlock(&vnode->lock);
  69
  70                         inode->i_mode   = S_IFDIR | 0555;
  71                         inode->i_op     = &afs_mntpt_inode_operations;
  72                         inode->i_fop    = &afs_mntpt_file_operations;
  73                 } else {
  74                         inode->i_mode   = S_IFLNK | vnode->status.mode;
  75                         inode->i_op     = &afs_symlink_inode_operations;
  76                 }
  77                 inode_nohighmem(inode);
  78                 break;
  79         default:
  80                 printk("kAFS: AFS vnode with undefined type\n");
  81                 return -EBADMSG;
  82         }
  83
  84 #ifdef CONFIG_AFS_FSCACHE
  85         if (vnode->status.size != inode->i_size)
  86                 fscache_attr_changed(vnode->cache);
  87 #endif
  88
  89         set_nlink(inode, vnode->status.nlink);
  90         inode->i_uid            = vnode->status.owner;
  91         inode->i_gid            = vnode->status.group;
  92         inode->i_size           = vnode->status.size;
  93         inode->i_ctime.tv_sec   = vnode->status.mtime_client;
  94         inode->i_ctime.tv_nsec  = 0;
  95         inode->i_atime          = inode->i_mtime = inode->i_ctime;
  96         inode->i_blocks         = 0;
  97         inode->i_generation     = vnode->fid.unique;
  98         inode->i_version        = vnode->status.data_version;
  99         inode->i_mapping->a_ops = &afs_fs_aops;
 100         return 0;
 101 }
 102
 103 /*
 104  * iget5() comparator
 105  */
 106 static int afs_iget5_test(struct inode *inode, void *opaque)
 107 {
 108         struct afs_iget_data *data = opaque;
 109
 110         return inode->i_ino == data->fid.vnode &&
 111                 inode->i_generation == data->fid.unique;
 112 }
 113
 114 /*
 115  * iget5() comparator for inode created by autocell operations
 116  *
 117  * These pseudo inodes don't match anything.
 118  */
 119 static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
 120 {
 121         return 0;
 122 }
 123
 124 /*
 125  * iget5() inode initialiser
 126  */
 127 static int afs_iget5_set(struct inode *inode, void *opaque)
 128 {
 129         struct afs_iget_data *data = opaque;
 130         struct afs_vnode *vnode = AFS_FS_I(inode);
 131
 132         inode->i_ino = data->fid.vnode;
 133         inode->i_generation = data->fid.unique;
 134         vnode->fid = data->fid;
 135         vnode->volume = data->volume;
 136
 137         return 0;
 138 }
 139
 140 /*
 141  * inode retrieval for autocell
 142  */
 143 struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
 144                                 int namesz, struct key *key)
 145 {
 146         struct afs_iget_data data;
 147         struct afs_super_info *as;
 148         struct afs_vnode *vnode;
 149         struct super_block *sb;
 150         struct inode *inode;
 151         static atomic_t afs_autocell_ino;
 152
 153         _enter("{%x:%u},%*.*s,",
 154                AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
 155                namesz, namesz, dev_name ?: "");
 156
 157         sb = dir->i_sb;
 158         as = sb->s_fs_info;
 159         data.volume = as->volume;
 160         data.fid.vid = as->volume->vid;
 161         data.fid.unique = 0;
 162         data.fid.vnode = 0;
 163
 164         inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
 165                              afs_iget5_autocell_test, afs_iget5_set,
 166                              &data);
 167         if (!inode) {
 168                 _leave(" = -ENOMEM");
 169                 return ERR_PTR(-ENOMEM);
 170         }
 171
 172         _debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
 173                inode, inode->i_ino, data.fid.vid, data.fid.vnode,
 174                data.fid.unique);
 175
 176         vnode = AFS_FS_I(inode);
 177
 178         /* there shouldn't be an existing inode */
 179         BUG_ON(!(inode->i_state & I_NEW));
 180
 181         inode->i_size           = 0;
 182         inode->i_mode           = S_IFDIR | S_IRUGO | S_IXUGO;
 183         inode->i_op             = &afs_autocell_inode_operations;
 184         set_nlink(inode, 2);
 185         inode->i_uid            = GLOBAL_ROOT_UID;
 186         inode->i_gid            = GLOBAL_ROOT_GID;
 187         inode->i_ctime.tv_sec   = get_seconds();
 188         inode->i_ctime.tv_nsec  = 0;
 189         inode->i_atime          = inode->i_mtime = inode->i_ctime;
 190         inode->i_blocks         = 0;
 191         inode->i_version        = 0;
 192         inode->i_generation     = 0;
 193
 194         set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
 195         set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
 196         inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
 197         unlock_new_inode(inode);
 198         _leave(" = %p", inode);
 199         return inode;
 200 }
 201
 202 /*
 203  * inode retrieval
 204  */
 205 struct inode *afs_iget(struct super_block *sb, struct key *key,
 206                        struct afs_fid *fid, struct afs_file_status *status,
 207                        struct afs_callback *cb)
 208 {
 209         struct afs_iget_data data = { .fid = *fid };
 210         struct afs_super_info *as;
 211         struct afs_vnode *vnode;
 212         struct inode *inode;
 213         int ret;
 214
 215         _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
 216
 217         as = sb->s_fs_info;
 218         data.volume = as->volume;
 219
 220         inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
 221                              &data);
 222         if (!inode) {
 223                 _leave(" = -ENOMEM");
 224                 return ERR_PTR(-ENOMEM);
 225         }
 226
 227         _debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
 228                inode, fid->vid, fid->vnode, fid->unique);
 229
 230         vnode = AFS_FS_I(inode);
 231
 232         /* deal with an existing inode */
 233         if (!(inode->i_state & I_NEW)) {
 234                 _leave(" = %p", inode);
 235                 return inode;
 236         }
 237
 238         if (!status) {
 239                 /* it's a remotely extant inode */
 240                 set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 241                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 242                 if (ret < 0)
 243                         goto bad_inode;
 244         } else {
 245                 /* it's an inode we just created */
 246                 memcpy(&vnode->status, status, sizeof(vnode->status));
 247
 248                 if (!cb) {
 249                         /* it's a symlink we just created (the fileserver
 250                          * didn't give us a callback) */
 251                         vnode->cb_version = 0;
 252                         vnode->cb_expiry = 0;
 253                         vnode->cb_type = 0;
 254                         vnode->cb_expires = ktime_get_real_seconds();
 255                 } else {
 256                         vnode->cb_version = cb->version;
 257                         vnode->cb_expiry = cb->expiry;
 258                         vnode->cb_type = cb->type;
 259                         vnode->cb_expires = vnode->cb_expiry +
 260                                 ktime_get_real_seconds();
 261                 }
 262         }
 263
 264         /* set up caching before mapping the status, as map-status reads the
 265          * first page of symlinks to see if they're really mountpoints */
 266         inode->i_size = vnode->status.size;
 267 #ifdef CONFIG_AFS_FSCACHE
 268         vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
 269                                               &afs_vnode_cache_index_def,
 270                                               vnode, true);
 271 #endif
 272
 273         ret = afs_inode_map_status(vnode, key);
 274         if (ret < 0)
 275                 goto bad_inode;
 276
 277         /* success */
 278         clear_bit(AFS_VNODE_UNSET, &vnode->flags);
 279         inode->i_flags |= S_NOATIME;
 280         unlock_new_inode(inode);
 281         _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
 282         return inode;
 283
 284         /* failure */
 285 bad_inode:
 286 #ifdef CONFIG_AFS_FSCACHE
 287         fscache_relinquish_cookie(vnode->cache, 0);
 288         vnode->cache = NULL;
 289 #endif
 290         iget_failed(inode);
 291         _leave(" = %d [bad]", ret);
 292         return ERR_PTR(ret);
 293 }
 294
 295 /*
 296  * mark the data attached to an inode as obsolete due to a write on the server
 297  * - might also want to ditch all the outstanding writes and dirty pages
 298  */
 299 void afs_zap_data(struct afs_vnode *vnode)
 300 {
 301         _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
 302
 303         /* nuke all the non-dirty pages that aren't locked, mapped or being
 304          * written back in a regular file and completely discard the pages in a
 305          * directory or symlink */
 306         if (S_ISREG(vnode->vfs_inode.i_mode))
 307                 invalidate_remote_inode(&vnode->vfs_inode);
 308         else
 309                 invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
 310 }
 311
 312 /*
 313  * validate a vnode/inode
 314  * - there are several things we need to check
 315  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
 316  *     symlink)
 317  *   - parent dir metadata changed (security changes)
 318  *   - dentry data changed (write, truncate)
 319  *   - dentry metadata changed (security changes)
 320  */
 321 int afs_validate(struct afs_vnode *vnode, struct key *key)
 322 {
 323         int ret;
 324
 325         _enter("{v={%x:%u} fl=%lx},%x",
 326                vnode->fid.vid, vnode->fid.vnode, vnode->flags,
 327                key_serial(key));
 328
 329         if (vnode->cb_promised &&
 330             !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
 331             !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
 332             !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
 333                 if (vnode->cb_expires < ktime_get_real_seconds() + 10) {
 334                         _debug("callback expired");
 335                         set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 336                 } else {
 337                         goto valid;
 338                 }
 339         }
 340
 341         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 342                 goto valid;
 343
 344         mutex_lock(&vnode->validate_lock);
 345
 346         /* if the promise has expired, we need to check the server again to get
 347          * a new promise - note that if the (parent) directory's metadata was
 348          * changed then the security may be different and we may no longer have
 349          * access */
 350         if (!vnode->cb_promised ||
 351             test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
 352                 _debug("not promised");
 353                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 354                 if (ret < 0)
 355                         goto error_unlock;
 356                 _debug("new promise [fl=%lx]", vnode->flags);
 357         }
 358
 359         if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 360                 _debug("file already deleted");
 361                 ret = -ESTALE;
 362                 goto error_unlock;
 363         }
 364
 365         /* if the vnode's data version number changed then its contents are
 366          * different */
 367         if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
 368                 afs_zap_data(vnode);
 369
 370         clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
 371         mutex_unlock(&vnode->validate_lock);
 372 valid:
 373         _leave(" = 0");
 374         return 0;
 375
 376 error_unlock:
 377         mutex_unlock(&vnode->validate_lock);
 378         _leave(" = %d", ret);
 379         return ret;
 380 }
 381
 382 /*
 383  * read the attributes of an inode
 384  */
 385 int afs_getattr(const struct path *path, struct kstat *stat,
 386                 u32 request_mask, unsigned int query_flags)
 387 {
 388         struct inode *inode = d_inode(path->dentry);
 389
 390         _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
 391
 392         generic_fillattr(inode, stat);
 393         return 0;
 394 }
 395
 396 /*
 397  * discard an AFS inode
 398  */
 399 int afs_drop_inode(struct inode *inode)
 400 {
 401         _enter("");
 402
 403         if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
 404                 return generic_delete_inode(inode);
 405         else
 406                 return generic_drop_inode(inode);
 407 }
 408
 409 /*
 410  * clear an AFS inode
 411  */
 412 void afs_evict_inode(struct inode *inode)
 413 {
 414         struct afs_permits *permits;
 415         struct afs_vnode *vnode;
 416
 417         vnode = AFS_FS_I(inode);
 418
 419         _enter("{%x:%u.%d} v=%u x=%u t=%u }",
 420                vnode->fid.vid,
 421                vnode->fid.vnode,
 422                vnode->fid.unique,
 423                vnode->cb_version,
 424                vnode->cb_expiry,
 425                vnode->cb_type);
 426
 427         _debug("CLEAR INODE %p", inode);
 428
 429         ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
 430
 431         truncate_inode_pages_final(&inode->i_data);
 432         clear_inode(inode);
 433
 434         afs_give_up_callback(vnode);
 435
 436         if (vnode->server) {
 437                 spin_lock(&vnode->server->fs_lock);
 438                 rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
 439                 spin_unlock(&vnode->server->fs_lock);
 440                 afs_put_server(vnode->server);
 441                 vnode->server = NULL;
 442         }
 443
 444         ASSERT(list_empty(&vnode->writebacks));
 445         ASSERT(!vnode->cb_promised);
 446
 447 #ifdef CONFIG_AFS_FSCACHE
 448         fscache_relinquish_cookie(vnode->cache, 0);
 449         vnode->cache = NULL;
 450 #endif
 451
 452         mutex_lock(&vnode->permits_lock);
 453         permits = vnode->permits;
 454         RCU_INIT_POINTER(vnode->permits, NULL);
 455         mutex_unlock(&vnode->permits_lock);
 456         if (permits)
 457                 call_rcu(&permits->rcu, afs_zap_permits);
 458
 459         _leave("");
 460 }
 461
 462 /*
 463  * set the attributes of an inode
 464  */
 465 int afs_setattr(struct dentry *dentry, struct iattr *attr)
 466 {
 467         struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 468         struct key *key;
 469         int ret;
 470
 471         _enter("{%x:%u},{n=%pd},%x",
 472                vnode->fid.vid, vnode->fid.vnode, dentry,
 473                attr->ia_valid);
 474
 475         if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
 476                                 ATTR_MTIME))) {
 477                 _leave(" = 0 [unsupported]");
 478                 return 0;
 479         }
 480
 481         /* flush any dirty data outstanding on a regular file */
 482         if (S_ISREG(vnode->vfs_inode.i_mode)) {
 483                 filemap_write_and_wait(vnode->vfs_inode.i_mapping);
 484                 afs_writeback_all(vnode);
 485         }
 486
 487         if (attr->ia_valid & ATTR_FILE) {
 488                 key = attr->ia_file->private_data;
 489         } else {
 490                 key = afs_request_key(vnode->volume->cell);
 491                 if (IS_ERR(key)) {
 492                         ret = PTR_ERR(key);
 493                         goto error;
 494                 }
 495         }
 496
 497         ret = afs_vnode_setattr(vnode, key, attr);
 498         if (!(attr->ia_valid & ATTR_FILE))
 499                 key_put(key);
 500
 501 error:
 502         _leave(" = %d", ret);
 503         return ret;
 504 }