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