linux/fs/afs/super.c
<<
>>
Prefs
   1/* AFS superblock handling
   2 *
   3 * Copyright (c) 2002, 2007 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@infradead.org>
  14 *
  15 */
  16
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/mount.h>
  20#include <linux/init.h>
  21#include <linux/slab.h>
  22#include <linux/fs.h>
  23#include <linux/pagemap.h>
  24#include <linux/parser.h>
  25#include <linux/statfs.h>
  26#include <linux/sched.h>
  27#include "internal.h"
  28
  29#define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
  30
  31static void afs_i_init_once(void *foo);
  32static struct dentry *afs_mount(struct file_system_type *fs_type,
  33                      int flags, const char *dev_name, void *data);
  34static void afs_kill_super(struct super_block *sb);
  35static struct inode *afs_alloc_inode(struct super_block *sb);
  36static void afs_destroy_inode(struct inode *inode);
  37static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
  38
  39struct file_system_type afs_fs_type = {
  40        .owner          = THIS_MODULE,
  41        .name           = "afs",
  42        .mount          = afs_mount,
  43        .kill_sb        = afs_kill_super,
  44        .fs_flags       = 0,
  45};
  46
  47static const struct super_operations afs_super_ops = {
  48        .statfs         = afs_statfs,
  49        .alloc_inode    = afs_alloc_inode,
  50        .drop_inode     = afs_drop_inode,
  51        .destroy_inode  = afs_destroy_inode,
  52        .evict_inode    = afs_evict_inode,
  53        .show_options   = generic_show_options,
  54};
  55
  56static struct kmem_cache *afs_inode_cachep;
  57static atomic_t afs_count_active_inodes;
  58
  59enum {
  60        afs_no_opt,
  61        afs_opt_cell,
  62        afs_opt_rwpath,
  63        afs_opt_vol,
  64        afs_opt_autocell,
  65};
  66
  67static const match_table_t afs_options_list = {
  68        { afs_opt_cell,         "cell=%s"       },
  69        { afs_opt_rwpath,       "rwpath"        },
  70        { afs_opt_vol,          "vol=%s"        },
  71        { afs_opt_autocell,     "autocell"      },
  72        { afs_no_opt,           NULL            },
  73};
  74
  75/*
  76 * initialise the filesystem
  77 */
  78int __init afs_fs_init(void)
  79{
  80        int ret;
  81
  82        _enter("");
  83
  84        /* create ourselves an inode cache */
  85        atomic_set(&afs_count_active_inodes, 0);
  86
  87        ret = -ENOMEM;
  88        afs_inode_cachep = kmem_cache_create("afs_inode_cache",
  89                                             sizeof(struct afs_vnode),
  90                                             0,
  91                                             SLAB_HWCACHE_ALIGN,
  92                                             afs_i_init_once);
  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                _leave(" = %d", ret);
 103                return ret;
 104        }
 105
 106        _leave(" = 0");
 107        return 0;
 108}
 109
 110/*
 111 * clean up the filesystem
 112 */
 113void __exit afs_fs_exit(void)
 114{
 115        _enter("");
 116
 117        afs_mntpt_kill_timer();
 118        unregister_filesystem(&afs_fs_type);
 119
 120        if (atomic_read(&afs_count_active_inodes) != 0) {
 121                printk("kAFS: %d active inode objects still present\n",
 122                       atomic_read(&afs_count_active_inodes));
 123                BUG();
 124        }
 125
 126        kmem_cache_destroy(afs_inode_cachep);
 127        _leave("");
 128}
 129
 130/*
 131 * parse the mount options
 132 * - this function has been shamelessly adapted from the ext3 fs which
 133 *   shamelessly adapted it from the msdos fs
 134 */
 135static int afs_parse_options(struct afs_mount_params *params,
 136                             char *options, const char **devname)
 137{
 138        struct afs_cell *cell;
 139        substring_t args[MAX_OPT_ARGS];
 140        char *p;
 141        int token;
 142
 143        _enter("%s", options);
 144
 145        options[PAGE_SIZE - 1] = 0;
 146
 147        while ((p = strsep(&options, ","))) {
 148                if (!*p)
 149                        continue;
 150
 151                token = match_token(p, afs_options_list, args);
 152                switch (token) {
 153                case afs_opt_cell:
 154                        cell = afs_cell_lookup(args[0].from,
 155                                               args[0].to - args[0].from,
 156                                               false);
 157                        if (IS_ERR(cell))
 158                                return PTR_ERR(cell);
 159                        afs_put_cell(params->cell);
 160                        params->cell = cell;
 161                        break;
 162
 163                case afs_opt_rwpath:
 164                        params->rwpath = 1;
 165                        break;
 166
 167                case afs_opt_vol:
 168                        *devname = args[0].from;
 169                        break;
 170
 171                case afs_opt_autocell:
 172                        params->autocell = 1;
 173                        break;
 174
 175                default:
 176                        printk(KERN_ERR "kAFS:"
 177                               " Unknown or invalid mount option: '%s'\n", p);
 178                        return -EINVAL;
 179                }
 180        }
 181
 182        _leave(" = 0");
 183        return 0;
 184}
 185
 186/*
 187 * parse a device name to get cell name, volume name, volume type and R/W
 188 * selector
 189 * - this can be one of the following:
 190 *      "%[cell:]volume[.]"             R/W volume
 191 *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 192 *                                       or R/W (rwpath=1) volume
 193 *      "%[cell:]volume.readonly"       R/O volume
 194 *      "#[cell:]volume.readonly"       R/O volume
 195 *      "%[cell:]volume.backup"         Backup volume
 196 *      "#[cell:]volume.backup"         Backup volume
 197 */
 198static int afs_parse_device_name(struct afs_mount_params *params,
 199                                 const char *name)
 200{
 201        struct afs_cell *cell;
 202        const char *cellname, *suffix;
 203        int cellnamesz;
 204
 205        _enter(",%s", name);
 206
 207        if (!name) {
 208                printk(KERN_ERR "kAFS: no volume name specified\n");
 209                return -EINVAL;
 210        }
 211
 212        if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 213                printk(KERN_ERR "kAFS: unparsable volume name\n");
 214                return -EINVAL;
 215        }
 216
 217        /* determine the type of volume we're looking for */
 218        params->type = AFSVL_ROVOL;
 219        params->force = false;
 220        if (params->rwpath || name[0] == '%') {
 221                params->type = AFSVL_RWVOL;
 222                params->force = true;
 223        }
 224        name++;
 225
 226        /* split the cell name out if there is one */
 227        params->volname = strchr(name, ':');
 228        if (params->volname) {
 229                cellname = name;
 230                cellnamesz = params->volname - name;
 231                params->volname++;
 232        } else {
 233                params->volname = name;
 234                cellname = NULL;
 235                cellnamesz = 0;
 236        }
 237
 238        /* the volume type is further affected by a possible suffix */
 239        suffix = strrchr(params->volname, '.');
 240        if (suffix) {
 241                if (strcmp(suffix, ".readonly") == 0) {
 242                        params->type = AFSVL_ROVOL;
 243                        params->force = true;
 244                } else if (strcmp(suffix, ".backup") == 0) {
 245                        params->type = AFSVL_BACKVOL;
 246                        params->force = true;
 247                } else if (suffix[1] == 0) {
 248                } else {
 249                        suffix = NULL;
 250                }
 251        }
 252
 253        params->volnamesz = suffix ?
 254                suffix - params->volname : strlen(params->volname);
 255
 256        _debug("cell %*.*s [%p]",
 257               cellnamesz, cellnamesz, cellname ?: "", params->cell);
 258
 259        /* lookup the cell record */
 260        if (cellname || !params->cell) {
 261                cell = afs_cell_lookup(cellname, cellnamesz, true);
 262                if (IS_ERR(cell)) {
 263                        printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
 264                               cellnamesz, cellnamesz, cellname ?: "");
 265                        return PTR_ERR(cell);
 266                }
 267                afs_put_cell(params->cell);
 268                params->cell = cell;
 269        }
 270
 271        _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 272               params->cell->name, params->cell,
 273               params->volnamesz, params->volnamesz, params->volname,
 274               suffix ?: "-", params->type, params->force ? " FORCE" : "");
 275
 276        return 0;
 277}
 278
 279/*
 280 * check a superblock to see if it's the one we're looking for
 281 */
 282static int afs_test_super(struct super_block *sb, void *data)
 283{
 284        struct afs_super_info *as1 = data;
 285        struct afs_super_info *as = sb->s_fs_info;
 286
 287        return as->volume == as1->volume;
 288}
 289
 290static int afs_set_super(struct super_block *sb, void *data)
 291{
 292        sb->s_fs_info = data;
 293        return set_anon_super(sb, NULL);
 294}
 295
 296/*
 297 * fill in the superblock
 298 */
 299static int afs_fill_super(struct super_block *sb,
 300                          struct afs_mount_params *params)
 301{
 302        struct afs_super_info *as = sb->s_fs_info;
 303        struct afs_fid fid;
 304        struct inode *inode = NULL;
 305        int ret;
 306
 307        _enter("");
 308
 309        /* fill in the superblock */
 310        sb->s_blocksize         = PAGE_CACHE_SIZE;
 311        sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 312        sb->s_magic             = AFS_FS_MAGIC;
 313        sb->s_op                = &afs_super_ops;
 314        sb->s_bdi               = &as->volume->bdi;
 315        strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
 316
 317        /* allocate the root inode and dentry */
 318        fid.vid         = as->volume->vid;
 319        fid.vnode       = 1;
 320        fid.unique      = 1;
 321        inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 322        if (IS_ERR(inode))
 323                return PTR_ERR(inode);
 324
 325        if (params->autocell)
 326                set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 327
 328        ret = -ENOMEM;
 329        sb->s_root = d_make_root(inode);
 330        if (!sb->s_root)
 331                goto error;
 332
 333        sb->s_d_op = &afs_fs_dentry_operations;
 334
 335        _leave(" = 0");
 336        return 0;
 337
 338error:
 339        _leave(" = %d", ret);
 340        return ret;
 341}
 342
 343/*
 344 * get an AFS superblock
 345 */
 346static struct dentry *afs_mount(struct file_system_type *fs_type,
 347                      int flags, const char *dev_name, void *options)
 348{
 349        struct afs_mount_params params;
 350        struct super_block *sb;
 351        struct afs_volume *vol;
 352        struct key *key;
 353        char *new_opts = kstrdup(options, GFP_KERNEL);
 354        struct afs_super_info *as;
 355        int ret;
 356
 357        _enter(",,%s,%p", dev_name, options);
 358
 359        memset(&params, 0, sizeof(params));
 360
 361        /* parse the options and device name */
 362        if (options) {
 363                ret = afs_parse_options(&params, options, &dev_name);
 364                if (ret < 0)
 365                        goto error;
 366        }
 367
 368        ret = afs_parse_device_name(&params, dev_name);
 369        if (ret < 0)
 370                goto error;
 371
 372        /* try and do the mount securely */
 373        key = afs_request_key(params.cell);
 374        if (IS_ERR(key)) {
 375                _leave(" = %ld [key]", PTR_ERR(key));
 376                ret = PTR_ERR(key);
 377                goto error;
 378        }
 379        params.key = key;
 380
 381        /* parse the device name */
 382        vol = afs_volume_lookup(&params);
 383        if (IS_ERR(vol)) {
 384                ret = PTR_ERR(vol);
 385                goto error;
 386        }
 387
 388        /* allocate a superblock info record */
 389        as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 390        if (!as) {
 391                ret = -ENOMEM;
 392                afs_put_volume(vol);
 393                goto error;
 394        }
 395        as->volume = vol;
 396
 397        /* allocate a deviceless superblock */
 398        sb = sget(fs_type, afs_test_super, afs_set_super, flags, as);
 399        if (IS_ERR(sb)) {
 400                ret = PTR_ERR(sb);
 401                afs_put_volume(vol);
 402                kfree(as);
 403                goto error;
 404        }
 405
 406        if (!sb->s_root) {
 407                /* initial superblock/root creation */
 408                _debug("create");
 409                ret = afs_fill_super(sb, &params);
 410                if (ret < 0) {
 411                        deactivate_locked_super(sb);
 412                        goto error;
 413                }
 414                save_mount_options(sb, new_opts);
 415                sb->s_flags |= MS_ACTIVE;
 416        } else {
 417                _debug("reuse");
 418                ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 419                afs_put_volume(vol);
 420                kfree(as);
 421        }
 422
 423        afs_put_cell(params.cell);
 424        kfree(new_opts);
 425        _leave(" = 0 [%p]", sb);
 426        return dget(sb->s_root);
 427
 428error:
 429        afs_put_cell(params.cell);
 430        key_put(params.key);
 431        kfree(new_opts);
 432        _leave(" = %d", ret);
 433        return ERR_PTR(ret);
 434}
 435
 436static void afs_kill_super(struct super_block *sb)
 437{
 438        struct afs_super_info *as = sb->s_fs_info;
 439        kill_anon_super(sb);
 440        afs_put_volume(as->volume);
 441        kfree(as);
 442}
 443
 444/*
 445 * initialise an inode cache slab element prior to any use
 446 */
 447static void afs_i_init_once(void *_vnode)
 448{
 449        struct afs_vnode *vnode = _vnode;
 450
 451        memset(vnode, 0, sizeof(*vnode));
 452        inode_init_once(&vnode->vfs_inode);
 453        init_waitqueue_head(&vnode->update_waitq);
 454        mutex_init(&vnode->permits_lock);
 455        mutex_init(&vnode->validate_lock);
 456        spin_lock_init(&vnode->writeback_lock);
 457        spin_lock_init(&vnode->lock);
 458        INIT_LIST_HEAD(&vnode->writebacks);
 459        INIT_LIST_HEAD(&vnode->pending_locks);
 460        INIT_LIST_HEAD(&vnode->granted_locks);
 461        INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 462        INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 463}
 464
 465/*
 466 * allocate an AFS inode struct from our slab cache
 467 */
 468static struct inode *afs_alloc_inode(struct super_block *sb)
 469{
 470        struct afs_vnode *vnode;
 471
 472        vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 473        if (!vnode)
 474                return NULL;
 475
 476        atomic_inc(&afs_count_active_inodes);
 477
 478        memset(&vnode->fid, 0, sizeof(vnode->fid));
 479        memset(&vnode->status, 0, sizeof(vnode->status));
 480
 481        vnode->volume           = NULL;
 482        vnode->update_cnt       = 0;
 483        vnode->flags            = 1 << AFS_VNODE_UNSET;
 484        vnode->cb_promised      = false;
 485
 486        _leave(" = %p", &vnode->vfs_inode);
 487        return &vnode->vfs_inode;
 488}
 489
 490static void afs_i_callback(struct rcu_head *head)
 491{
 492        struct inode *inode = container_of(head, struct inode, i_rcu);
 493        struct afs_vnode *vnode = AFS_FS_I(inode);
 494        kmem_cache_free(afs_inode_cachep, vnode);
 495}
 496
 497/*
 498 * destroy an AFS inode struct
 499 */
 500static void afs_destroy_inode(struct inode *inode)
 501{
 502        struct afs_vnode *vnode = AFS_FS_I(inode);
 503
 504        _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 505
 506        _debug("DESTROY INODE %p", inode);
 507
 508        ASSERTCMP(vnode->server, ==, NULL);
 509
 510        call_rcu(&inode->i_rcu, afs_i_callback);
 511        atomic_dec(&afs_count_active_inodes);
 512}
 513
 514/*
 515 * return information about an AFS volume
 516 */
 517static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 518{
 519        struct afs_volume_status vs;
 520        struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 521        struct key *key;
 522        int ret;
 523
 524        key = afs_request_key(vnode->volume->cell);
 525        if (IS_ERR(key))
 526                return PTR_ERR(key);
 527
 528        ret = afs_vnode_get_volume_status(vnode, key, &vs);
 529        key_put(key);
 530        if (ret < 0) {
 531                _leave(" = %d", ret);
 532                return ret;
 533        }
 534
 535        buf->f_type     = dentry->d_sb->s_magic;
 536        buf->f_bsize    = AFS_BLOCK_SIZE;
 537        buf->f_namelen  = AFSNAMEMAX - 1;
 538
 539        if (vs.max_quota == 0)
 540                buf->f_blocks = vs.part_max_blocks;
 541        else
 542                buf->f_blocks = vs.max_quota;
 543        buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 544        return 0;
 545}
 546
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.