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         set_nlink(inode, vnode->status.nlink);
  71         inode->i_uid            = vnode->status.owner;
  72         inode->i_gid            = GLOBAL_ROOT_GID;
  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_generation     = vnode->fid.unique;
  79         inode->i_version        = vnode->status.data_version;
  80         inode->i_mapping->a_ops = &afs_fs_aops;
  81
  82         /* check to see whether a symbolic link is really a mountpoint */
  83         if (vnode->status.type == AFS_FTYPE_SYMLINK) {
  84                 afs_mntpt_check_symlink(vnode, key);
  85
  86                 if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
  87                         inode->i_mode   = S_IFDIR | vnode->status.mode;
  88                         inode->i_op     = &afs_mntpt_inode_operations;
  89                         inode->i_fop    = &afs_mntpt_file_operations;
  90                 }
  91         }
  92
  93         return 0;
  94 }
  95
  96 /*
  97  * iget5() comparator
  98  */
  99 static int afs_iget5_test(struct inode *inode, void *opaque)
 100 {
 101         struct afs_iget_data *data = opaque;
 102
 103         return inode->i_ino == data->fid.vnode &&
 104                 inode->i_generation == data->fid.unique;
 105 }
 106
 107 /*
 108  * iget5() comparator for inode created by autocell operations
 109  *
 110  * These pseudo inodes don't match anything.
 111  */
 112 static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
 113 {
 114         return 0;
 115 }
 116
 117 /*
 118  * iget5() inode initialiser
 119  */
 120 static int afs_iget5_set(struct inode *inode, void *opaque)
 121 {
 122         struct afs_iget_data *data = opaque;
 123         struct afs_vnode *vnode = AFS_FS_I(inode);
 124
 125         inode->i_ino = data->fid.vnode;
 126         inode->i_generation = data->fid.unique;
 127         vnode->fid = data->fid;
 128         vnode->volume = data->volume;
 129
 130         return 0;
 131 }
 132
 133 /*
 134  * inode retrieval for autocell
 135  */
 136 struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
 137                                 int namesz, struct key *key)
 138 {
 139         struct afs_iget_data data;
 140         struct afs_super_info *as;
 141         struct afs_vnode *vnode;
 142         struct super_block *sb;
 143         struct inode *inode;
 144         static atomic_t afs_autocell_ino;
 145
 146         _enter("{%x:%u},%*.*s,",
 147                AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
 148                namesz, namesz, dev_name ?: "");
 149
 150         sb = dir->i_sb;
 151         as = sb->s_fs_info;
 152         data.volume = as->volume;
 153         data.fid.vid = as->volume->vid;
 154         data.fid.unique = 0;
 155         data.fid.vnode = 0;
 156
 157         inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
 158                              afs_iget5_autocell_test, afs_iget5_set,
 159                              &data);
 160         if (!inode) {
 161                 _leave(" = -ENOMEM");
 162                 return ERR_PTR(-ENOMEM);
 163         }
 164
 165         _debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
 166                inode, inode->i_ino, data.fid.vid, data.fid.vnode,
 167                data.fid.unique);
 168
 169         vnode = AFS_FS_I(inode);
 170
 171         /* there shouldn't be an existing inode */
 172         BUG_ON(!(inode->i_state & I_NEW));
 173
 174         inode->i_size           = 0;
 175         inode->i_mode           = S_IFDIR | S_IRUGO | S_IXUGO;
 176         inode->i_op             = &afs_autocell_inode_operations;
 177         set_nlink(inode, 2);
 178         inode->i_uid            = GLOBAL_ROOT_UID;
 179         inode->i_gid            = GLOBAL_ROOT_GID;
 180         inode->i_ctime.tv_sec   = get_seconds();
 181         inode->i_ctime.tv_nsec  = 0;
 182         inode->i_atime          = inode->i_mtime = inode->i_ctime;
 183         inode->i_blocks         = 0;
 184         inode->i_version        = 0;
 185         inode->i_generation     = 0;
 186
 187         set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
 188         set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
 189         inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
 190         unlock_new_inode(inode);
 191         _leave(" = %p", inode);
 192         return inode;
 193 }
 194
 195 /*
 196  * inode retrieval
 197  */
 198 struct inode *afs_iget(struct super_block *sb, struct key *key,
 199                        struct afs_fid *fid, struct afs_file_status *status,
 200                        struct afs_callback *cb)
 201 {
 202         struct afs_iget_data data = { .fid = *fid };
 203         struct afs_super_info *as;
 204         struct afs_vnode *vnode;
 205         struct inode *inode;
 206         int ret;
 207
 208         _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
 209
 210         as = sb->s_fs_info;
 211         data.volume = as->volume;
 212
 213         inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
 214                              &data);
 215         if (!inode) {
 216                 _leave(" = -ENOMEM");
 217                 return ERR_PTR(-ENOMEM);
 218         }
 219
 220         _debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
 221                inode, fid->vid, fid->vnode, fid->unique);
 222
 223         vnode = AFS_FS_I(inode);
 224
 225         /* deal with an existing inode */
 226         if (!(inode->i_state & I_NEW)) {
 227                 _leave(" = %p", inode);
 228                 return inode;
 229         }
 230
 231         if (!status) {
 232                 /* it's a remotely extant inode */
 233                 set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 234                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 235                 if (ret < 0)
 236                         goto bad_inode;
 237         } else {
 238                 /* it's an inode we just created */
 239                 memcpy(&vnode->status, status, sizeof(vnode->status));
 240
 241                 if (!cb) {
 242                         /* it's a symlink we just created (the fileserver
 243                          * didn't give us a callback) */
 244                         vnode->cb_version = 0;
 245                         vnode->cb_expiry = 0;
 246                         vnode->cb_type = 0;
 247                         vnode->cb_expires = get_seconds();
 248                 } else {
 249                         vnode->cb_version = cb->version;
 250                         vnode->cb_expiry = cb->expiry;
 251                         vnode->cb_type = cb->type;
 252                         vnode->cb_expires = vnode->cb_expiry + get_seconds();
 253                 }
 254         }
 255
 256         /* set up caching before mapping the status, as map-status reads the
 257          * first page of symlinks to see if they're really mountpoints */
 258         inode->i_size = vnode->status.size;
 259 #ifdef CONFIG_AFS_FSCACHE
 260         vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
 261                                               &afs_vnode_cache_index_def,
 262                                               vnode, true);
 263 #endif
 264
 265         ret = afs_inode_map_status(vnode, key);
 266         if (ret < 0)
 267                 goto bad_inode;
 268
 269         /* success */
 270         clear_bit(AFS_VNODE_UNSET, &vnode->flags);
 271         inode->i_flags |= S_NOATIME;
 272         unlock_new_inode(inode);
 273         _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
 274         return inode;
 275
 276         /* failure */
 277 bad_inode:
 278 #ifdef CONFIG_AFS_FSCACHE
 279         fscache_relinquish_cookie(vnode->cache, 0);
 280         vnode->cache = NULL;
 281 #endif
 282         iget_failed(inode);
 283         _leave(" = %d [bad]", ret);
 284         return ERR_PTR(ret);
 285 }
 286
 287 /*
 288  * mark the data attached to an inode as obsolete due to a write on the server
 289  * - might also want to ditch all the outstanding writes and dirty pages
 290  */
 291 void afs_zap_data(struct afs_vnode *vnode)
 292 {
 293         _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
 294
 295         /* nuke all the non-dirty pages that aren't locked, mapped or being
 296          * written back in a regular file and completely discard the pages in a
 297          * directory or symlink */
 298         if (S_ISREG(vnode->vfs_inode.i_mode))
 299                 invalidate_remote_inode(&vnode->vfs_inode);
 300         else
 301                 invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
 302 }
 303
 304 /*
 305  * validate a vnode/inode
 306  * - there are several things we need to check
 307  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
 308  *     symlink)
 309  *   - parent dir metadata changed (security changes)
 310  *   - dentry data changed (write, truncate)
 311  *   - dentry metadata changed (security changes)
 312  */
 313 int afs_validate(struct afs_vnode *vnode, struct key *key)
 314 {
 315         int ret;
 316
 317         _enter("{v={%x:%u} fl=%lx},%x",
 318                vnode->fid.vid, vnode->fid.vnode, vnode->flags,
 319                key_serial(key));
 320
 321         if (vnode->cb_promised &&
 322             !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
 323             !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
 324             !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
 325                 if (vnode->cb_expires < get_seconds() + 10) {
 326                         _debug("callback expired");
 327                         set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 328                 } else {
 329                         goto valid;
 330                 }
 331         }
 332
 333         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 334                 goto valid;
 335
 336         mutex_lock(&vnode->validate_lock);
 337
 338         /* if the promise has expired, we need to check the server again to get
 339          * a new promise - note that if the (parent) directory's metadata was
 340          * changed then the security may be different and we may no longer have
 341          * access */
 342         if (!vnode->cb_promised ||
 343             test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
 344                 _debug("not promised");
 345                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 346                 if (ret < 0)
 347                         goto error_unlock;
 348                 _debug("new promise [fl=%lx]", vnode->flags);
 349         }
 350
 351         if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 352                 _debug("file already deleted");
 353                 ret = -ESTALE;
 354                 goto error_unlock;
 355         }
 356
 357         /* if the vnode's data version number changed then its contents are
 358          * different */
 359         if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
 360                 afs_zap_data(vnode);
 361
 362         clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
 363         mutex_unlock(&vnode->validate_lock);
 364 valid:
 365         _leave(" = 0");
 366         return 0;
 367
 368 error_unlock:
 369         mutex_unlock(&vnode->validate_lock);
 370         _leave(" = %d", ret);
 371         return ret;
 372 }
 373
 374 /*
 375  * read the attributes of an inode
 376  */
 377 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 378                       struct kstat *stat)
 379 {
 380         struct inode *inode;
 381
 382         inode = dentry->d_inode;
 383
 384         _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
 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_final(&inode->i_data);
 426         clear_inode(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 }