fs/afs/super.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 Howells <dhowells@redhat.com>
  12  *          David Woodhouse <dwmw2@cambridge.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 "vnode.h"
  23 #include "volume.h"
  24 #include "cell.h"
  25 #include "cmservice.h"
  26 #include "fsclient.h"
  27 #include "super.h"
  28 #include "internal.h"
  29
  30 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
  31
  32 struct afs_mount_params {
  33         int                     rwpath;
  34         struct afs_cell         *default_cell;
  35         struct afs_volume       *volume;
  36 };
  37
  38 static void afs_i_init_once(void *foo, kmem_cache_t *cachep,
  39                             unsigned long flags);
  40
  41 static struct super_block *afs_get_sb(struct file_system_type *fs_type,
  42                                       int flags, const char *dev_name,
  43                                       void *data);
  44
  45 static struct inode *afs_alloc_inode(struct super_block *sb);
  46
  47 static void afs_put_super(struct super_block *sb);
  48
  49 static void afs_destroy_inode(struct inode *inode);
  50
  51 static struct file_system_type afs_fs_type = {
  52         .owner          = THIS_MODULE,
  53         .name           = "afs",
  54         .get_sb         = afs_get_sb,
  55         .kill_sb        = kill_anon_super,
  56         .fs_flags       = FS_BINARY_MOUNTDATA,
  57 };
  58
  59 static struct super_operations afs_super_ops = {
  60         .statfs         = simple_statfs,
  61         .alloc_inode    = afs_alloc_inode,
  62         .drop_inode     = generic_delete_inode,
  63         .destroy_inode  = afs_destroy_inode,
  64         .clear_inode    = afs_clear_inode,
  65         .put_super      = afs_put_super,
  66 };
  67
  68 static kmem_cache_t *afs_inode_cachep;
  69 static atomic_t afs_count_active_inodes;
  70
  71 /*****************************************************************************/
  72 /*
  73  * initialise the filesystem
  74  */
  75 int __init afs_fs_init(void)
  76 {
  77         int ret;
  78
  79         _enter("");
  80
  81         afs_timer_init(&afs_mntpt_expiry_timer, &afs_mntpt_expiry_timer_ops);
  82
  83         /* create ourselves an inode cache */
  84         atomic_set(&afs_count_active_inodes, 0);
  85
  86         ret = -ENOMEM;
  87         afs_inode_cachep = kmem_cache_create("afs_inode_cache",
  88                                              sizeof(struct afs_vnode),
  89                                              0,
  90                                              SLAB_HWCACHE_ALIGN,
  91                                              afs_i_init_once,
  92                                              NULL);
  93         if (!afs_inode_cachep) {
  94                 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
  95                 return ret;
  96         }
  97
  98         /* now export our filesystem to lesser mortals */
  99         ret = register_filesystem(&afs_fs_type);
 100         if (ret < 0) {
 101                 kmem_cache_destroy(afs_inode_cachep);
 102                 kleave(" = %d", ret);
 103                 return ret;
 104         }
 105
 106         kleave(" = 0");
 107         return 0;
 108 } /* end afs_fs_init() */
 109
 110 /*****************************************************************************/
 111 /*
 112  * clean up the filesystem
 113  */
 114 void __exit afs_fs_exit(void)
 115 {
 116         unregister_filesystem(&afs_fs_type);
 117
 118         if (atomic_read(&afs_count_active_inodes) != 0) {
 119                 printk("kAFS: %d active inode objects still present\n",
 120                        atomic_read(&afs_count_active_inodes));
 121                 BUG();
 122         }
 123
 124         kmem_cache_destroy(afs_inode_cachep);
 125
 126 } /* end afs_fs_exit() */
 127
 128 /*****************************************************************************/
 129 /*
 130  * check that an argument has a value
 131  */
 132 static int want_arg(char **_value, const char *option)
 133 {
 134         if (!_value || !*_value || !**_value) {
 135                 printk(KERN_NOTICE "kAFS: %s: argument missing\n", option);
 136                 return 0;
 137         }
 138         return 1;
 139 } /* end want_arg() */
 140
 141 /*****************************************************************************/
 142 /*
 143  * check that there's no subsequent value
 144  */
 145 static int want_no_value(char *const *_value, const char *option)
 146 {
 147         if (*_value && **_value) {
 148                 printk(KERN_NOTICE "kAFS: %s: Invalid argument: %s\n",
 149                        option, *_value);
 150                 return 0;
 151         }
 152         return 1;
 153 } /* end want_no_value() */
 154
 155 /*****************************************************************************/
 156 /*
 157  * parse the mount options
 158  * - this function has been shamelessly adapted from the ext3 fs which
 159  *   shamelessly adapted it from the msdos fs
 160  */
 161 static int afs_super_parse_options(struct afs_mount_params *params,
 162                                    char *options,
 163                                    const char **devname)
 164 {
 165         char *key, *value;
 166         int ret;
 167
 168         _enter("%s", options);
 169
 170         options[PAGE_SIZE - 1] = 0;
 171
 172         ret = 0;
 173         while ((key = strsep(&options, ",")) != 0)
 174         {
 175                 value = strchr(key, '=');
 176                 if (value)
 177                         *value++ = 0;
 178
 179                 printk("kAFS: KEY: %s, VAL:%s\n", key, value ?: "-");
 180
 181                 if (strcmp(key, "rwpath") == 0) {
 182                         if (!want_no_value(&value, "rwpath"))
 183                                 return -EINVAL;
 184                         params->rwpath = 1;
 185                         continue;
 186                 }
 187                 else if (strcmp(key, "vol") == 0) {
 188                         if (!want_arg(&value, "vol"))
 189                                 return -EINVAL;
 190                         *devname = value;
 191                         continue;
 192                 }
 193                 else if (strcmp(key, "cell") == 0) {
 194                         if (!want_arg(&value, "cell"))
 195                                 return -EINVAL;
 196                         afs_put_cell(params->default_cell);
 197                         ret = afs_cell_lookup(value,
 198                                               strlen(value),
 199                                               &params->default_cell);
 200                         if (ret < 0)
 201                                 return -EINVAL;
 202                         continue;
 203                 }
 204
 205                 printk("kAFS: Unknown mount option: '%s'\n",  key);
 206                 ret = -EINVAL;
 207                 goto error;
 208         }
 209
 210         ret = 0;
 211
 212  error:
 213         _leave(" = %d", ret);
 214         return ret;
 215 } /* end afs_super_parse_options() */
 216
 217 /*****************************************************************************/
 218 /*
 219  * check a superblock to see if it's the one we're looking for
 220  */
 221 static int afs_test_super(struct super_block *sb, void *data)
 222 {
 223         struct afs_mount_params *params = data;
 224         struct afs_super_info *as = sb->s_fs_info;
 225
 226         return as->volume == params->volume;
 227 } /* end afs_test_super() */
 228
 229 /*****************************************************************************/
 230 /*
 231  * fill in the superblock
 232  */
 233 static int afs_fill_super(struct super_block *sb, void *data, int silent)
 234 {
 235         struct afs_mount_params *params = data;
 236         struct afs_super_info *as = NULL;
 237         struct afs_fid fid;
 238         struct dentry *root = NULL;
 239         struct inode *inode = NULL;
 240         int ret;
 241
 242         kenter("");
 243
 244         /* allocate a superblock info record */
 245         as = kmalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 246         if (!as) {
 247                 _leave(" = -ENOMEM");
 248                 return -ENOMEM;
 249         }
 250
 251         memset(as, 0, sizeof(struct afs_super_info));
 252
 253         afs_get_volume(params->volume);
 254         as->volume = params->volume;
 255
 256         /* fill in the superblock */
 257         sb->s_blocksize         = PAGE_CACHE_SIZE;
 258         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 259         sb->s_magic             = AFS_FS_MAGIC;
 260         sb->s_op                = &afs_super_ops;
 261         sb->s_fs_info           = as;
 262
 263         /* allocate the root inode and dentry */
 264         fid.vid         = as->volume->vid;
 265         fid.vnode       = 1;
 266         fid.unique      = 1;
 267         ret = afs_iget(sb, &fid, &inode);
 268         if (ret < 0)
 269                 goto error;
 270
 271         ret = -ENOMEM;
 272         root = d_alloc_root(inode);
 273         if (!root)
 274                 goto error;
 275
 276         sb->s_root = root;
 277
 278         kleave(" = 0");
 279         return 0;
 280
 281  error:
 282         iput(inode);
 283         afs_put_volume(as->volume);
 284         kfree(as);
 285
 286         sb->s_fs_info = NULL;
 287
 288         kleave(" = %d", ret);
 289         return ret;
 290 } /* end afs_fill_super() */
 291
 292 /*****************************************************************************/
 293 /*
 294  * get an AFS superblock
 295  * - TODO: don't use get_sb_nodev(), but rather call sget() directly
 296  */
 297 static struct super_block *afs_get_sb(struct file_system_type *fs_type,
 298                                       int flags,
 299                                       const char *dev_name,
 300                                       void *options)
 301 {
 302         struct afs_mount_params params;
 303         struct super_block *sb;
 304         int ret;
 305
 306         _enter(",,%s,%p", dev_name, options);
 307
 308         memset(&params, 0, sizeof(params));
 309
 310         /* start the cache manager */
 311         ret = afscm_start();
 312         if (ret < 0) {
 313                 _leave(" = %d", ret);
 314                 return ERR_PTR(ret);
 315         }
 316
 317         /* parse the options */
 318         if (options) {
 319                 ret = afs_super_parse_options(&params, options, &dev_name);
 320                 if (ret < 0)
 321                         goto error;
 322                 if (!dev_name) {
 323                         printk("kAFS: no volume name specified\n");
 324                         ret = -EINVAL;
 325                         goto error;
 326                 }
 327         }
 328
 329         /* parse the device name */
 330         ret = afs_volume_lookup(dev_name,
 331                                 params.default_cell,
 332                                 params.rwpath,
 333                                 &params.volume);
 334         if (ret < 0)
 335                 goto error;
 336
 337         /* allocate a deviceless superblock */
 338         sb = sget(fs_type, afs_test_super, set_anon_super, &params);
 339         if (IS_ERR(sb))
 340                 goto error;
 341
 342         sb->s_flags = flags;
 343
 344         ret = afs_fill_super(sb, &params, flags & MS_VERBOSE ? 1 : 0);
 345         if (ret < 0) {
 346                 up_write(&sb->s_umount);
 347                 deactivate_super(sb);
 348                 goto error;
 349         }
 350         sb->s_flags |= MS_ACTIVE;
 351
 352         afs_put_volume(params.volume);
 353         afs_put_cell(params.default_cell);
 354         _leave(" = %p", sb);
 355         return sb;
 356
 357  error:
 358         afs_put_volume(params.volume);
 359         afs_put_cell(params.default_cell);
 360         afscm_stop();
 361         _leave(" = %d", ret);
 362         return ERR_PTR(ret);
 363 } /* end afs_get_sb() */
 364
 365 /*****************************************************************************/
 366 /*
 367  * finish the unmounting process on the superblock
 368  */
 369 static void afs_put_super(struct super_block *sb)
 370 {
 371         struct afs_super_info *as = sb->s_fs_info;
 372
 373         _enter("");
 374
 375         afs_put_volume(as->volume);
 376         afscm_stop();
 377
 378         _leave("");
 379 } /* end afs_put_super() */
 380
 381 /*****************************************************************************/
 382 /*
 383  * initialise an inode cache slab element prior to any use
 384  */
 385 static void afs_i_init_once(void *_vnode, kmem_cache_t *cachep,
 386                             unsigned long flags)
 387 {
 388         struct afs_vnode *vnode = (struct afs_vnode *) _vnode;
 389
 390         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 391             SLAB_CTOR_CONSTRUCTOR) {
 392                 memset(vnode, 0, sizeof(*vnode));
 393                 inode_init_once(&vnode->vfs_inode);
 394                 init_waitqueue_head(&vnode->update_waitq);
 395                 spin_lock_init(&vnode->lock);
 396                 INIT_LIST_HEAD(&vnode->cb_link);
 397                 INIT_LIST_HEAD(&vnode->cb_hash_link);
 398                 afs_timer_init(&vnode->cb_timeout,
 399                                &afs_vnode_cb_timed_out_ops);
 400         }
 401
 402 } /* end afs_i_init_once() */
 403
 404 /*****************************************************************************/
 405 /*
 406  * allocate an AFS inode struct from our slab cache
 407  */
 408 static struct inode *afs_alloc_inode(struct super_block *sb)
 409 {
 410         struct afs_vnode *vnode;
 411
 412         vnode = (struct afs_vnode *)
 413                 kmem_cache_alloc(afs_inode_cachep, SLAB_KERNEL);
 414         if (!vnode)
 415                 return NULL;
 416
 417         atomic_inc(&afs_count_active_inodes);
 418
 419         memset(&vnode->fid, 0, sizeof(vnode->fid));
 420         memset(&vnode->status, 0, sizeof(vnode->status));
 421
 422         vnode->volume           = NULL;
 423         vnode->update_cnt       = 0;
 424         vnode->flags            = 0;
 425
 426         return &vnode->vfs_inode;
 427 } /* end afs_alloc_inode() */
 428
 429 /*****************************************************************************/
 430 /*
 431  * destroy an AFS inode struct
 432  */
 433 static void afs_destroy_inode(struct inode *inode)
 434 {
 435         _enter("{%lu}", inode->i_ino);
 436
 437         kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
 438
 439         atomic_dec(&afs_count_active_inodes);
 440
 441 } /* end afs_destroy_inode() */