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