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         set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
 188         inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
 189         unlock_new_inode(inode);
 190         _leave(" = %p", inode);
 191         return inode;
 192 }
 193
 194 /*
 195  * inode retrieval
 196  */
 197 struct inode *afs_iget(struct super_block *sb, struct key *key,
 198                        struct afs_fid *fid, struct afs_file_status *status,
 199                        struct afs_callback *cb)
 200 {
 201         struct afs_iget_data data = { .fid = *fid };
 202         struct afs_super_info *as;
 203         struct afs_vnode *vnode;
 204         struct inode *inode;
 205         int ret;
 206
 207         _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
 208
 209         as = sb->s_fs_info;
 210         data.volume = as->volume;
 211
 212         inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
 213                              &data);
 214         if (!inode) {
 215                 _leave(" = -ENOMEM");
 216                 return ERR_PTR(-ENOMEM);
 217         }
 218
 219         _debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
 220                inode, fid->vid, fid->vnode, fid->unique);
 221
 222         vnode = AFS_FS_I(inode);
 223
 224         /* deal with an existing inode */
 225         if (!(inode->i_state & I_NEW)) {
 226                 _leave(" = %p", inode);
 227                 return inode;
 228         }
 229
 230         if (!status) {
 231                 /* it's a remotely extant inode */
 232                 set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 233                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 234                 if (ret < 0)
 235                         goto bad_inode;
 236         } else {
 237                 /* it's an inode we just created */
 238                 memcpy(&vnode->status, status, sizeof(vnode->status));
 239
 240                 if (!cb) {
 241                         /* it's a symlink we just created (the fileserver
 242                          * didn't give us a callback) */
 243                         vnode->cb_version = 0;
 244                         vnode->cb_expiry = 0;
 245                         vnode->cb_type = 0;
 246                         vnode->cb_expires = get_seconds();
 247                 } else {
 248                         vnode->cb_version = cb->version;
 249                         vnode->cb_expiry = cb->expiry;
 250                         vnode->cb_type = cb->type;
 251                         vnode->cb_expires = vnode->cb_expiry + get_seconds();
 252                 }
 253         }
 254
 255         /* set up caching before mapping the status, as map-status reads the
 256          * first page of symlinks to see if they're really mountpoints */
 257         inode->i_size = vnode->status.size;
 258 #ifdef CONFIG_AFS_FSCACHE
 259         vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
 260                                               &afs_vnode_cache_index_def,
 261                                               vnode);
 262 #endif
 263
 264         ret = afs_inode_map_status(vnode, key);
 265         if (ret < 0)
 266                 goto bad_inode;
 267
 268         /* success */
 269         clear_bit(AFS_VNODE_UNSET, &vnode->flags);
 270         inode->i_flags |= S_NOATIME;
 271         unlock_new_inode(inode);
 272         _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
 273         return inode;
 274
 275         /* failure */
 276 bad_inode:
 277 #ifdef CONFIG_AFS_FSCACHE
 278         fscache_relinquish_cookie(vnode->cache, 0);
 279         vnode->cache = NULL;
 280 #endif
 281         iget_failed(inode);
 282         _leave(" = %d [bad]", ret);
 283         return ERR_PTR(ret);
 284 }
 285
 286 /*
 287  * mark the data attached to an inode as obsolete due to a write on the server
 288  * - might also want to ditch all the outstanding writes and dirty pages
 289  */
 290 void afs_zap_data(struct afs_vnode *vnode)
 291 {
 292         _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
 293
 294         /* nuke all the non-dirty pages that aren't locked, mapped or being
 295          * written back in a regular file and completely discard the pages in a
 296          * directory or symlink */
 297         if (S_ISREG(vnode->vfs_inode.i_mode))
 298                 invalidate_remote_inode(&vnode->vfs_inode);
 299         else
 300                 invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
 301 }
 302
 303 /*
 304  * validate a vnode/inode
 305  * - there are several things we need to check
 306  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
 307  *     symlink)
 308  *   - parent dir metadata changed (security changes)
 309  *   - dentry data changed (write, truncate)
 310  *   - dentry metadata changed (security changes)
 311  */
 312 int afs_validate(struct afs_vnode *vnode, struct key *key)
 313 {
 314         int ret;
 315
 316         _enter("{v={%x:%u} fl=%lx},%x",
 317                vnode->fid.vid, vnode->fid.vnode, vnode->flags,
 318                key_serial(key));
 319
 320         if (vnode->cb_promised &&
 321             !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
 322             !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
 323             !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
 324                 if (vnode->cb_expires < get_seconds() + 10) {
 325                         _debug("callback expired");
 326                         set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 327                 } else {
 328                         goto valid;
 329                 }
 330         }
 331
 332         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 333                 goto valid;
 334
 335         mutex_lock(&vnode->validate_lock);
 336
 337         /* if the promise has expired, we need to check the server again to get
 338          * a new promise - note that if the (parent) directory's metadata was
 339          * changed then the security may be different and we may no longer have
 340          * access */
 341         if (!vnode->cb_promised ||
 342             test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
 343                 _debug("not promised");
 344                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 345                 if (ret < 0)
 346                         goto error_unlock;
 347                 _debug("new promise [fl=%lx]", vnode->flags);
 348         }
 349
 350         if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 351                 _debug("file already deleted");
 352                 ret = -ESTALE;
 353                 goto error_unlock;
 354         }
 355
 356         /* if the vnode's data version number changed then its contents are
 357          * different */
 358         if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
 359                 afs_zap_data(vnode);
 360
 361         clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
 362         mutex_unlock(&vnode->validate_lock);
 363 valid:
 364         _leave(" = 0");
 365         return 0;
 366
 367 error_unlock:
 368         mutex_unlock(&vnode->validate_lock);
 369         _leave(" = %d", ret);
 370         return ret;
 371 }
 372
 373 /*
 374  * read the attributes of an inode
 375  */
 376 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 377                       struct kstat *stat)
 378 {
 379         struct inode *inode;
 380
 381         inode = dentry->d_inode;
 382
 383         _enter("{ ino=%lu v=%llu }", inode->i_ino,
 384                 (unsigned long long)inode->i_version);
 385
 386         generic_fillattr(inode, stat);
 387         return 0;
 388 }
 389
 390 /*
 391  * discard an AFS inode
 392  */
 393 int afs_drop_inode(struct inode *inode)
 394 {
 395         _enter("");
 396
 397         if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
 398                 return generic_delete_inode(inode);
 399         else
 400                 return generic_drop_inode(inode);
 401 }
 402
 403 /*
 404  * clear an AFS inode
 405  */
 406 void afs_evict_inode(struct inode *inode)
 407 {
 408         struct afs_permits *permits;
 409         struct afs_vnode *vnode;
 410
 411         vnode = AFS_FS_I(inode);
 412
 413         _enter("{%x:%u.%d} v=%u x=%u t=%u }",
 414                vnode->fid.vid,
 415                vnode->fid.vnode,
 416                vnode->fid.unique,
 417                vnode->cb_version,
 418                vnode->cb_expiry,
 419                vnode->cb_type);
 420
 421         _debug("CLEAR INODE %p", inode);
 422
 423         ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
 424
 425         truncate_inode_pages(&inode->i_data, 0);
 426         end_writeback(inode);
 427
 428         afs_give_up_callback(vnode);
 429
 430         if (vnode->server) {
 431                 spin_lock(&vnode->server->fs_lock);
 432                 rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
 433                 spin_unlock(&vnode->server->fs_lock);
 434                 afs_put_server(vnode->server);
 435                 vnode->server = NULL;
 436         }
 437
 438         ASSERT(list_empty(&vnode->writebacks));
 439         ASSERT(!vnode->cb_promised);
 440
 441 #ifdef CONFIG_AFS_FSCACHE
 442         fscache_relinquish_cookie(vnode->cache, 0);
 443         vnode->cache = NULL;
 444 #endif
 445
 446         mutex_lock(&vnode->permits_lock);
 447         permits = vnode->permits;
 448         rcu_assign_pointer(vnode->permits, NULL);
 449         mutex_unlock(&vnode->permits_lock);
 450         if (permits)
 451                 call_rcu(&permits->rcu, afs_zap_permits);
 452
 453         _leave("");
 454 }
 455
 456 /*
 457  * set the attributes of an inode
 458  */
 459 int afs_setattr(struct dentry *dentry, struct iattr *attr)
 460 {
 461         struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 462         struct key *key;
 463         int ret;
 464
 465         _enter("{%x:%u},{n=%s},%x",
 466                vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
 467                attr->ia_valid);
 468
 469         if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
 470                                 ATTR_MTIME))) {
 471                 _leave(" = 0 [unsupported]");
 472                 return 0;
 473         }
 474
 475         /* flush any dirty data outstanding on a regular file */
 476         if (S_ISREG(vnode->vfs_inode.i_mode)) {
 477                 filemap_write_and_wait(vnode->vfs_inode.i_mapping);
 478                 afs_writeback_all(vnode);
 479         }
 480
 481         if (attr->ia_valid & ATTR_FILE) {
 482                 key = attr->ia_file->private_data;
 483         } else {
 484                 key = afs_request_key(vnode->volume->cell);
 485                 if (IS_ERR(key)) {
 486                         ret = PTR_ERR(key);
 487                         goto error;
 488                 }
 489         }
 490
 491         ret = afs_vnode_setattr(vnode, key, attr);
 492         if (!(attr->ia_valid & ATTR_FILE))
 493                 key_put(key);
 494
 495 error:
 496         _leave(" = %d", ret);
 497         return ret;
 498 }