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 "internal.h"
  23
  24 struct afs_iget_data {
  25         struct afs_fid          fid;
  26         struct afs_volume       *volume;        /* volume on which resides */
  27 };
  28
  29 /*
  30  * map the AFS file status to the inode member variables
  31  */
  32 static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
  33 {
  34         struct inode *inode = AFS_VNODE_TO_I(vnode);
  35
  36         _debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
  37                vnode->status.type,
  38                vnode->status.nlink,
  39                (unsigned long long) vnode->status.size,
  40                vnode->status.data_version,
  41                vnode->status.mode);
  42
  43         switch (vnode->status.type) {
  44         case AFS_FTYPE_FILE:
  45                 inode->i_mode   = S_IFREG | vnode->status.mode;
  46                 inode->i_op     = &afs_file_inode_operations;
  47                 inode->i_fop    = &afs_file_operations;
  48                 break;
  49         case AFS_FTYPE_DIR:
  50                 inode->i_mode   = S_IFDIR | vnode->status.mode;
  51                 inode->i_op     = &afs_dir_inode_operations;
  52                 inode->i_fop    = &afs_dir_file_operations;
  53                 break;
  54         case AFS_FTYPE_SYMLINK:
  55                 inode->i_mode   = S_IFLNK | vnode->status.mode;
  56                 inode->i_op     = &page_symlink_inode_operations;
  57                 break;
  58         default:
  59                 printk("kAFS: AFS vnode with undefined type\n");
  60                 return -EBADMSG;
  61         }
  62
  63 #ifdef CONFIG_AFS_FSCACHE
  64         if (vnode->status.size != inode->i_size)
  65                 fscache_attr_changed(vnode->cache);
  66 #endif
  67
  68         inode->i_nlink          = vnode->status.nlink;
  69         inode->i_uid            = vnode->status.owner;
  70         inode->i_gid            = 0;
  71         inode->i_size           = vnode->status.size;
  72         inode->i_ctime.tv_sec   = vnode->status.mtime_server;
  73         inode->i_ctime.tv_nsec  = 0;
  74         inode->i_atime          = inode->i_mtime = inode->i_ctime;
  75         inode->i_blocks         = 0;
  76         inode->i_version        = vnode->fid.unique;
  77         inode->i_mapping->a_ops = &afs_fs_aops;
  78
  79         /* check to see whether a symbolic link is really a mountpoint */
  80         if (vnode->status.type == AFS_FTYPE_SYMLINK) {
  81                 afs_mntpt_check_symlink(vnode, key);
  82
  83                 if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
  84                         inode->i_mode   = S_IFDIR | vnode->status.mode;
  85                         inode->i_op     = &afs_mntpt_inode_operations;
  86                         inode->i_fop    = &afs_mntpt_file_operations;
  87                 }
  88         }
  89
  90         return 0;
  91 }
  92
  93 /*
  94  * iget5() comparator
  95  */
  96 static int afs_iget5_test(struct inode *inode, void *opaque)
  97 {
  98         struct afs_iget_data *data = opaque;
  99
 100         return inode->i_ino == data->fid.vnode &&
 101                 inode->i_version == data->fid.unique;
 102 }
 103
 104 /*
 105  * iget5() inode initialiser
 106  */
 107 static int afs_iget5_set(struct inode *inode, void *opaque)
 108 {
 109         struct afs_iget_data *data = opaque;
 110         struct afs_vnode *vnode = AFS_FS_I(inode);
 111
 112         inode->i_ino = data->fid.vnode;
 113         inode->i_version = data->fid.unique;
 114         vnode->fid = data->fid;
 115         vnode->volume = data->volume;
 116
 117         return 0;
 118 }
 119
 120 /*
 121  * inode retrieval
 122  */
 123 struct inode *afs_iget(struct super_block *sb, struct key *key,
 124                        struct afs_fid *fid, struct afs_file_status *status,
 125                        struct afs_callback *cb)
 126 {
 127         struct afs_iget_data data = { .fid = *fid };
 128         struct afs_super_info *as;
 129         struct afs_vnode *vnode;
 130         struct inode *inode;
 131         int ret;
 132
 133         _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
 134
 135         as = sb->s_fs_info;
 136         data.volume = as->volume;
 137
 138         inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
 139                              &data);
 140         if (!inode) {
 141                 _leave(" = -ENOMEM");
 142                 return ERR_PTR(-ENOMEM);
 143         }
 144
 145         _debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
 146                inode, fid->vid, fid->vnode, fid->unique);
 147
 148         vnode = AFS_FS_I(inode);
 149
 150         /* deal with an existing inode */
 151         if (!(inode->i_state & I_NEW)) {
 152                 _leave(" = %p", inode);
 153                 return inode;
 154         }
 155
 156         if (!status) {
 157                 /* it's a remotely extant inode */
 158                 set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 159                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 160                 if (ret < 0)
 161                         goto bad_inode;
 162         } else {
 163                 /* it's an inode we just created */
 164                 memcpy(&vnode->status, status, sizeof(vnode->status));
 165
 166                 if (!cb) {
 167                         /* it's a symlink we just created (the fileserver
 168                          * didn't give us a callback) */
 169                         vnode->cb_version = 0;
 170                         vnode->cb_expiry = 0;
 171                         vnode->cb_type = 0;
 172                         vnode->cb_expires = get_seconds();
 173                 } else {
 174                         vnode->cb_version = cb->version;
 175                         vnode->cb_expiry = cb->expiry;
 176                         vnode->cb_type = cb->type;
 177                         vnode->cb_expires = vnode->cb_expiry + get_seconds();
 178                 }
 179         }
 180
 181         /* set up caching before mapping the status, as map-status reads the
 182          * first page of symlinks to see if they're really mountpoints */
 183         inode->i_size = vnode->status.size;
 184 #ifdef CONFIG_AFS_FSCACHE
 185         vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
 186                                               &afs_vnode_cache_index_def,
 187                                               vnode);
 188 #endif
 189
 190         ret = afs_inode_map_status(vnode, key);
 191         if (ret < 0)
 192                 goto bad_inode;
 193
 194         /* success */
 195         clear_bit(AFS_VNODE_UNSET, &vnode->flags);
 196         inode->i_flags |= S_NOATIME;
 197         unlock_new_inode(inode);
 198         _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
 199         return inode;
 200
 201         /* failure */
 202 bad_inode:
 203 #ifdef CONFIG_AFS_FSCACHE
 204         fscache_relinquish_cookie(vnode->cache, 0);
 205         vnode->cache = NULL;
 206 #endif
 207         iget_failed(inode);
 208         _leave(" = %d [bad]", ret);
 209         return ERR_PTR(ret);
 210 }
 211
 212 /*
 213  * mark the data attached to an inode as obsolete due to a write on the server
 214  * - might also want to ditch all the outstanding writes and dirty pages
 215  */
 216 void afs_zap_data(struct afs_vnode *vnode)
 217 {
 218         _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
 219
 220         /* nuke all the non-dirty pages that aren't locked, mapped or being
 221          * written back in a regular file and completely discard the pages in a
 222          * directory or symlink */
 223         if (S_ISREG(vnode->vfs_inode.i_mode))
 224                 invalidate_remote_inode(&vnode->vfs_inode);
 225         else
 226                 invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
 227 }
 228
 229 /*
 230  * validate a vnode/inode
 231  * - there are several things we need to check
 232  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
 233  *     symlink)
 234  *   - parent dir metadata changed (security changes)
 235  *   - dentry data changed (write, truncate)
 236  *   - dentry metadata changed (security changes)
 237  */
 238 int afs_validate(struct afs_vnode *vnode, struct key *key)
 239 {
 240         int ret;
 241
 242         _enter("{v={%x:%u} fl=%lx},%x",
 243                vnode->fid.vid, vnode->fid.vnode, vnode->flags,
 244                key_serial(key));
 245
 246         if (vnode->cb_promised &&
 247             !test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
 248             !test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
 249             !test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
 250                 if (vnode->cb_expires < get_seconds() + 10) {
 251                         _debug("callback expired");
 252                         set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
 253                 } else {
 254                         goto valid;
 255                 }
 256         }
 257
 258         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 259                 goto valid;
 260
 261         mutex_lock(&vnode->validate_lock);
 262
 263         /* if the promise has expired, we need to check the server again to get
 264          * a new promise - note that if the (parent) directory's metadata was
 265          * changed then the security may be different and we may no longer have
 266          * access */
 267         if (!vnode->cb_promised ||
 268             test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
 269                 _debug("not promised");
 270                 ret = afs_vnode_fetch_status(vnode, NULL, key);
 271                 if (ret < 0)
 272                         goto error_unlock;
 273                 _debug("new promise [fl=%lx]", vnode->flags);
 274         }
 275
 276         if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 277                 _debug("file already deleted");
 278                 ret = -ESTALE;
 279                 goto error_unlock;
 280         }
 281
 282         /* if the vnode's data version number changed then its contents are
 283          * different */
 284         if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
 285                 afs_zap_data(vnode);
 286
 287         clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
 288         mutex_unlock(&vnode->validate_lock);
 289 valid:
 290         _leave(" = 0");
 291         return 0;
 292
 293 error_unlock:
 294         mutex_unlock(&vnode->validate_lock);
 295         _leave(" = %d", ret);
 296         return ret;
 297 }
 298
 299 /*
 300  * read the attributes of an inode
 301  */
 302 int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 303                       struct kstat *stat)
 304 {
 305         struct inode *inode;
 306
 307         inode = dentry->d_inode;
 308
 309         _enter("{ ino=%lu v=%llu }", inode->i_ino,
 310                 (unsigned long long)inode->i_version);
 311
 312         generic_fillattr(inode, stat);
 313         return 0;
 314 }
 315
 316 /*
 317  * clear an AFS inode
 318  */
 319 void afs_evict_inode(struct inode *inode)
 320 {
 321         struct afs_permits *permits;
 322         struct afs_vnode *vnode;
 323
 324         vnode = AFS_FS_I(inode);
 325
 326         _enter("{%x:%u.%d} v=%u x=%u t=%u }",
 327                vnode->fid.vid,
 328                vnode->fid.vnode,
 329                vnode->fid.unique,
 330                vnode->cb_version,
 331                vnode->cb_expiry,
 332                vnode->cb_type);
 333
 334         _debug("CLEAR INODE %p", inode);
 335
 336         ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
 337
 338         truncate_inode_pages(&inode->i_data, 0);
 339         end_writeback(inode);
 340
 341         afs_give_up_callback(vnode);
 342
 343         if (vnode->server) {
 344                 spin_lock(&vnode->server->fs_lock);
 345                 rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
 346                 spin_unlock(&vnode->server->fs_lock);
 347                 afs_put_server(vnode->server);
 348                 vnode->server = NULL;
 349         }
 350
 351         ASSERT(list_empty(&vnode->writebacks));
 352         ASSERT(!vnode->cb_promised);
 353
 354 #ifdef CONFIG_AFS_FSCACHE
 355         fscache_relinquish_cookie(vnode->cache, 0);
 356         vnode->cache = NULL;
 357 #endif
 358
 359         mutex_lock(&vnode->permits_lock);
 360         permits = vnode->permits;
 361         rcu_assign_pointer(vnode->permits, NULL);
 362         mutex_unlock(&vnode->permits_lock);
 363         if (permits)
 364                 call_rcu(&permits->rcu, afs_zap_permits);
 365
 366         _leave("");
 367 }
 368
 369 /*
 370  * set the attributes of an inode
 371  */
 372 int afs_setattr(struct dentry *dentry, struct iattr *attr)
 373 {
 374         struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 375         struct key *key;
 376         int ret;
 377
 378         _enter("{%x:%u},{n=%s},%x",
 379                vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
 380                attr->ia_valid);
 381
 382         if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
 383                                 ATTR_MTIME))) {
 384                 _leave(" = 0 [unsupported]");
 385                 return 0;
 386         }
 387
 388         /* flush any dirty data outstanding on a regular file */
 389         if (S_ISREG(vnode->vfs_inode.i_mode)) {
 390                 filemap_write_and_wait(vnode->vfs_inode.i_mapping);
 391                 afs_writeback_all(vnode);
 392         }
 393
 394         if (attr->ia_valid & ATTR_FILE) {
 395                 key = attr->ia_file->private_data;
 396         } else {
 397                 key = afs_request_key(vnode->volume->cell);
 398                 if (IS_ERR(key)) {
 399                         ret = PTR_ERR(key);
 400                         goto error;
 401                 }
 402         }
 403
 404         ret = afs_vnode_setattr(vnode, key, attr);
 405         if (!(attr->ia_valid & ATTR_FILE))
 406                 key_put(key);
 407
 408 error:
 409         _leave(" = %d", ret);
 410         return ret;
 411 }