fs/afs/super.c

   1 /* AFS superblock handling
   2  *
   3  * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
   4  *
   5  * This software may be freely redistributed under the terms of the
   6  * GNU General Public License.
   7  *
   8  * You should have received a copy of the GNU General Public License
   9  * along with this program; if not, write to the Free Software
  10  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  11  *
  12  * Authors: David Howells <dhowells@redhat.com>
  13  *          David Woodhouse <dwmw2@redhat.com>
  14  *
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/slab.h>
  21 #include <linux/fs.h>
  22 #include <linux/pagemap.h>
  23 #include "vnode.h"
  24 #include "volume.h"
  25 #include "cell.h"
  26 #include "cmservice.h"
  27 #include "fsclient.h"
  28 #include "super.h"
  29 #include "internal.h"
  30
  31 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
  32
  33 struct afs_mount_params {
  34         int                     rwpath;
  35         struct afs_cell         *default_cell;
  36         struct afs_volume       *volume;
  37 };
  38
  39 static void afs_i_init_once(void *foo, struct kmem_cache *cachep,
  40                             unsigned long flags);
  41
  42 static int afs_get_sb(struct file_system_type *fs_type,
  43                       int flags, const char *dev_name,
  44                       void *data, struct vfsmount *mnt);
  45
  46 static struct inode *afs_alloc_inode(struct super_block *sb);
  47
  48 static void afs_put_super(struct super_block *sb);
  49
  50 static void afs_destroy_inode(struct inode *inode);
  51
  52 struct file_system_type afs_fs_type = {
  53         .owner          = THIS_MODULE,
  54         .name           = "afs",
  55         .get_sb         = afs_get_sb,
  56         .kill_sb        = kill_anon_super,
  57         .fs_flags       = FS_BINARY_MOUNTDATA,
  58 };
  59
  60 static const struct super_operations afs_super_ops = {
  61         .statfs         = simple_statfs,
  62         .alloc_inode    = afs_alloc_inode,
  63         .drop_inode     = generic_delete_inode,
  64         .destroy_inode  = afs_destroy_inode,
  65         .clear_inode    = afs_clear_inode,
  66         .put_super      = afs_put_super,
  67 };
  68
  69 static struct kmem_cache *afs_inode_cachep;
  70 static atomic_t afs_count_active_inodes;
  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 }
 109
 110 /*
 111  * clean up the filesystem
 112  */
 113 void __exit afs_fs_exit(void)
 114 {
 115         unregister_filesystem(&afs_fs_type);
 116
 117         if (atomic_read(&afs_count_active_inodes) != 0) {
 118                 printk("kAFS: %d active inode objects still present\n",
 119                        atomic_read(&afs_count_active_inodes));
 120                 BUG();
 121         }
 122
 123         kmem_cache_destroy(afs_inode_cachep);
 124 }
 125
 126 /*
 127  * check that an argument has a value
 128  */
 129 static int want_arg(char **_value, const char *option)
 130 {
 131         if (!_value || !*_value || !**_value) {
 132                 printk(KERN_NOTICE "kAFS: %s: argument missing\n", option);
 133                 return 0;
 134         }
 135         return 1;
 136 }
 137
 138 /*
 139  * check that there's no subsequent value
 140  */
 141 static int want_no_value(char *const *_value, const char *option)
 142 {
 143         if (*_value && **_value) {
 144                 printk(KERN_NOTICE "kAFS: %s: Invalid argument: %s\n",
 145                        option, *_value);
 146                 return 0;
 147         }
 148         return 1;
 149 }
 150
 151 /*
 152  * parse the mount options
 153  * - this function has been shamelessly adapted from the ext3 fs which
 154  *   shamelessly adapted it from the msdos fs
 155  */
 156 static int afs_super_parse_options(struct afs_mount_params *params,
 157                                    char *options,
 158                                    const char **devname)
 159 {
 160         char *key, *value;
 161         int ret;
 162
 163         _enter("%s", options);
 164
 165         options[PAGE_SIZE - 1] = 0;
 166
 167         ret = 0;
 168         while ((key = strsep(&options, ",")) != 0)
 169         {
 170                 value = strchr(key, '=');
 171                 if (value)
 172                         *value++ = 0;
 173
 174                 printk("kAFS: KEY: %s, VAL:%s\n", key, value ?: "-");
 175
 176                 if (strcmp(key, "rwpath") == 0) {
 177                         if (!want_no_value(&value, "rwpath"))
 178                                 return -EINVAL;
 179                         params->rwpath = 1;
 180                         continue;
 181                 } else if (strcmp(key, "vol") == 0) {
 182                         if (!want_arg(&value, "vol"))
 183                                 return -EINVAL;
 184                         *devname = value;
 185                         continue;
 186                 } else if (strcmp(key, "cell") == 0) {
 187                         if (!want_arg(&value, "cell"))
 188                                 return -EINVAL;
 189                         afs_put_cell(params->default_cell);
 190                         ret = afs_cell_lookup(value,
 191                                               strlen(value),
 192                                               &params->default_cell);
 193                         if (ret < 0)
 194                                 return -EINVAL;
 195                         continue;
 196                 }
 197
 198                 printk("kAFS: Unknown mount option: '%s'\n",  key);
 199                 ret = -EINVAL;
 200                 goto error;
 201         }
 202
 203         ret = 0;
 204
 205 error:
 206         _leave(" = %d", ret);
 207         return ret;
 208 }
 209
 210 /*
 211  * check a superblock to see if it's the one we're looking for
 212  */
 213 static int afs_test_super(struct super_block *sb, void *data)
 214 {
 215         struct afs_mount_params *params = data;
 216         struct afs_super_info *as = sb->s_fs_info;
 217
 218         return as->volume == params->volume;
 219 }
 220
 221 /*
 222  * fill in the superblock
 223  */
 224 static int afs_fill_super(struct super_block *sb, void *data, int silent)
 225 {
 226         struct afs_mount_params *params = data;
 227         struct afs_super_info *as = NULL;
 228         struct afs_fid fid;
 229         struct dentry *root = NULL;
 230         struct inode *inode = NULL;
 231         int ret;
 232
 233         kenter("");
 234
 235         /* allocate a superblock info record */
 236         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 237         if (!as) {
 238                 _leave(" = -ENOMEM");
 239                 return -ENOMEM;
 240         }
 241
 242         afs_get_volume(params->volume);
 243         as->volume = params->volume;
 244
 245         /* fill in the superblock */
 246         sb->s_blocksize         = PAGE_CACHE_SIZE;
 247         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 248         sb->s_magic             = AFS_FS_MAGIC;
 249         sb->s_op                = &afs_super_ops;
 250         sb->s_fs_info           = as;
 251
 252         /* allocate the root inode and dentry */
 253         fid.vid         = as->volume->vid;
 254         fid.vnode       = 1;
 255         fid.unique      = 1;
 256         ret = afs_iget(sb, &fid, &inode);
 257         if (ret < 0)
 258                 goto error;
 259
 260         ret = -ENOMEM;
 261         root = d_alloc_root(inode);
 262         if (!root)
 263                 goto error;
 264
 265         sb->s_root = root;
 266
 267         kleave(" = 0");
 268         return 0;
 269
 270 error:
 271         iput(inode);
 272         afs_put_volume(as->volume);
 273         kfree(as);
 274
 275         sb->s_fs_info = NULL;
 276
 277         kleave(" = %d", ret);
 278         return ret;
 279 }
 280
 281 /*
 282  * get an AFS superblock
 283  * - TODO: don't use get_sb_nodev(), but rather call sget() directly
 284  */
 285 static int afs_get_sb(struct file_system_type *fs_type,
 286                       int flags,
 287                       const char *dev_name,
 288                       void *options,
 289                       struct vfsmount *mnt)
 290 {
 291         struct afs_mount_params params;
 292         struct super_block *sb;
 293         int ret;
 294
 295         _enter(",,%s,%p", dev_name, options);
 296
 297         memset(&params, 0, sizeof(params));
 298
 299         /* start the cache manager */
 300         ret = afscm_start();
 301         if (ret < 0) {
 302                 _leave(" = %d", ret);
 303                 return ret;
 304         }
 305
 306         /* parse the options */
 307         if (options) {
 308                 ret = afs_super_parse_options(&params, options, &dev_name);
 309                 if (ret < 0)
 310                         goto error;
 311                 if (!dev_name) {
 312                         printk("kAFS: no volume name specified\n");
 313                         ret = -EINVAL;
 314                         goto error;
 315                 }
 316         }
 317
 318         /* parse the device name */
 319         ret = afs_volume_lookup(dev_name,
 320                                 params.default_cell,
 321                                 params.rwpath,
 322                                 &params.volume);
 323         if (ret < 0)
 324                 goto error;
 325
 326         /* allocate a deviceless superblock */
 327         sb = sget(fs_type, afs_test_super, set_anon_super, &params);
 328         if (IS_ERR(sb))
 329                 goto error;
 330
 331         sb->s_flags = flags;
 332
 333         ret = afs_fill_super(sb, &params, flags & MS_SILENT ? 1 : 0);
 334         if (ret < 0) {
 335                 up_write(&sb->s_umount);
 336                 deactivate_super(sb);
 337                 goto error;
 338         }
 339         sb->s_flags |= MS_ACTIVE;
 340         simple_set_mnt(mnt, sb);
 341
 342         afs_put_volume(params.volume);
 343         afs_put_cell(params.default_cell);
 344         _leave(" = 0 [%p]", 0, sb);
 345         return 0;
 346
 347 error:
 348         afs_put_volume(params.volume);
 349         afs_put_cell(params.default_cell);
 350         afscm_stop();
 351         _leave(" = %d", ret);
 352         return ret;
 353 }
 354
 355 /*
 356  * finish the unmounting process on the superblock
 357  */
 358 static void afs_put_super(struct super_block *sb)
 359 {
 360         struct afs_super_info *as = sb->s_fs_info;
 361
 362         _enter("");
 363
 364         afs_put_volume(as->volume);
 365         afscm_stop();
 366
 367         _leave("");
 368 }
 369
 370 /*
 371  * initialise an inode cache slab element prior to any use
 372  */
 373 static void afs_i_init_once(void *_vnode, struct kmem_cache *cachep,
 374                             unsigned long flags)
 375 {
 376         struct afs_vnode *vnode = _vnode;
 377
 378         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 379             SLAB_CTOR_CONSTRUCTOR) {
 380                 memset(vnode, 0, sizeof(*vnode));
 381                 inode_init_once(&vnode->vfs_inode);
 382                 init_waitqueue_head(&vnode->update_waitq);
 383                 spin_lock_init(&vnode->lock);
 384                 INIT_LIST_HEAD(&vnode->cb_link);
 385                 INIT_LIST_HEAD(&vnode->cb_hash_link);
 386                 afs_timer_init(&vnode->cb_timeout,
 387                                &afs_vnode_cb_timed_out_ops);
 388         }
 389 }
 390
 391 /*
 392  * allocate an AFS inode struct from our slab cache
 393  */
 394 static struct inode *afs_alloc_inode(struct super_block *sb)
 395 {
 396         struct afs_vnode *vnode;
 397
 398         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 399         if (!vnode)
 400                 return NULL;
 401
 402         atomic_inc(&afs_count_active_inodes);
 403
 404         memset(&vnode->fid, 0, sizeof(vnode->fid));
 405         memset(&vnode->status, 0, sizeof(vnode->status));
 406
 407         vnode->volume           = NULL;
 408         vnode->update_cnt       = 0;
 409         vnode->flags            = 0;
 410
 411         return &vnode->vfs_inode;
 412 }
 413
 414 /*
 415  * destroy an AFS inode struct
 416  */
 417 static void afs_destroy_inode(struct inode *inode)
 418 {
 419         _enter("{%lu}", inode->i_ino);
 420
 421         kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
 422         atomic_dec(&afs_count_active_inodes);
 423 }