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