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