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