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        /*
 127         * Make sure all delayed rcu free inodes are flushed before we
 128         * destroy cache.
 129         */
 130        rcu_barrier();
 131        kmem_cache_destroy(afs_inode_cachep);
 132        _leave("");
 133}
 134
 135/*
 136 * parse the mount options
 137 * - this function has been shamelessly adapted from the ext3 fs which
 138 *   shamelessly adapted it from the msdos fs
 139 */
 140static int afs_parse_options(struct afs_mount_params *params,
 141                             char *options, const char **devname)
 142{
 143        struct afs_cell *cell;
 144        substring_t args[MAX_OPT_ARGS];
 145        char *p;
 146        int token;
 147
 148        _enter("%s", options);
 149
 150        options[PAGE_SIZE - 1] = 0;
 151
 152        while ((p = strsep(&options, ","))) {
 153                if (!*p)
 154                        continue;
 155
 156                token = match_token(p, afs_options_list, args);
 157                switch (token) {
 158                case afs_opt_cell:
 159                        cell = afs_cell_lookup(args[0].from,
 160                                               args[0].to - args[0].from,
 161                                               false);
 162                        if (IS_ERR(cell))
 163                                return PTR_ERR(cell);
 164                        afs_put_cell(params->cell);
 165                        params->cell = cell;
 166                        break;
 167
 168                case afs_opt_rwpath:
 169                        params->rwpath = 1;
 170                        break;
 171
 172                case afs_opt_vol:
 173                        *devname = args[0].from;
 174                        break;
 175
 176                case afs_opt_autocell:
 177                        params->autocell = 1;
 178                        break;
 179
 180                default:
 181                        printk(KERN_ERR "kAFS:"
 182                               " Unknown or invalid mount option: '%s'\n", p);
 183                        return -EINVAL;
 184                }
 185        }
 186
 187        _leave(" = 0");
 188        return 0;
 189}
 190
 191/*
 192 * parse a device name to get cell name, volume name, volume type and R/W
 193 * selector
 194 * - this can be one of the following:
 195 *      "%[cell:]volume[.]"             R/W volume
 196 *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 197 *                                       or R/W (rwpath=1) volume
 198 *      "%[cell:]volume.readonly"       R/O volume
 199 *      "#[cell:]volume.readonly"       R/O volume
 200 *      "%[cell:]volume.backup"         Backup volume
 201 *      "#[cell:]volume.backup"         Backup volume
 202 */
 203static int afs_parse_device_name(struct afs_mount_params *params,
 204                                 const char *name)
 205{
 206        struct afs_cell *cell;
 207        const char *cellname, *suffix;
 208        int cellnamesz;
 209
 210        _enter(",%s", name);
 211
 212        if (!name) {
 213                printk(KERN_ERR "kAFS: no volume name specified\n");
 214                return -EINVAL;
 215        }
 216
 217        if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 218                printk(KERN_ERR "kAFS: unparsable volume name\n");
 219                return -EINVAL;
 220        }
 221
 222        /* determine the type of volume we're looking for */
 223        params->type = AFSVL_ROVOL;
 224        params->force = false;
 225        if (params->rwpath || name[0] == '%') {
 226                params->type = AFSVL_RWVOL;
 227                params->force = true;
 228        }
 229        name++;
 230
 231        /* split the cell name out if there is one */
 232        params->volname = strchr(name, ':');
 233        if (params->volname) {
 234                cellname = name;
 235                cellnamesz = params->volname - name;
 236                params->volname++;
 237        } else {
 238                params->volname = name;
 239                cellname = NULL;
 240                cellnamesz = 0;
 241        }
 242
 243        /* the volume type is further affected by a possible suffix */
 244        suffix = strrchr(params->volname, '.');
 245        if (suffix) {
 246                if (strcmp(suffix, ".readonly") == 0) {
 247                        params->type = AFSVL_ROVOL;
 248                        params->force = true;
 249                } else if (strcmp(suffix, ".backup") == 0) {
 250                        params->type = AFSVL_BACKVOL;
 251                        params->force = true;
 252                } else if (suffix[1] == 0) {
 253                } else {
 254                        suffix = NULL;
 255                }
 256        }
 257
 258        params->volnamesz = suffix ?
 259                suffix - params->volname : strlen(params->volname);
 260
 261        _debug("cell %*.*s [%p]",
 262               cellnamesz, cellnamesz, cellname ?: "", params->cell);
 263
 264        /* lookup the cell record */
 265        if (cellname || !params->cell) {
 266                cell = afs_cell_lookup(cellname, cellnamesz, true);
 267                if (IS_ERR(cell)) {
 268                        printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
 269                               cellnamesz, cellnamesz, cellname ?: "");
 270                        return PTR_ERR(cell);
 271                }
 272                afs_put_cell(params->cell);
 273                params->cell = cell;
 274        }
 275
 276        _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 277               params->cell->name, params->cell,
 278               params->volnamesz, params->volnamesz, params->volname,
 279               suffix ?: "-", params->type, params->force ? " FORCE" : "");
 280
 281        return 0;
 282}
 283
 284/*
 285 * check a superblock to see if it's the one we're looking for
 286 */
 287static int afs_test_super(struct super_block *sb, void *data)
 288{
 289        struct afs_super_info *as1 = data;
 290        struct afs_super_info *as = sb->s_fs_info;
 291
 292        return as->volume == as1->volume;
 293}
 294
 295static int afs_set_super(struct super_block *sb, void *data)
 296{
 297        sb->s_fs_info = data;
 298        return set_anon_super(sb, NULL);
 299}
 300
 301/*
 302 * fill in the superblock
 303 */
 304static int afs_fill_super(struct super_block *sb,
 305                          struct afs_mount_params *params)
 306{
 307        struct afs_super_info *as = sb->s_fs_info;
 308        struct afs_fid fid;
 309        struct inode *inode = NULL;
 310        int ret;
 311
 312        _enter("");
 313
 314        /* fill in the superblock */
 315        sb->s_blocksize         = PAGE_CACHE_SIZE;
 316        sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 317        sb->s_magic             = AFS_FS_MAGIC;
 318        sb->s_op                = &afs_super_ops;
 319        sb->s_bdi               = &as->volume->bdi;
 320        strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
 321
 322        /* allocate the root inode and dentry */
 323        fid.vid         = as->volume->vid;
 324        fid.vnode       = 1;
 325        fid.unique      = 1;
 326        inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 327        if (IS_ERR(inode))
 328                return PTR_ERR(inode);
 329
 330        if (params->autocell)
 331                set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 332
 333        ret = -ENOMEM;
 334        sb->s_root = d_make_root(inode);
 335        if (!sb->s_root)
 336                goto error;
 337
 338        sb->s_d_op = &afs_fs_dentry_operations;
 339
 340        _leave(" = 0");
 341        return 0;
 342
 343error:
 344        _leave(" = %d", ret);
 345        return ret;
 346}
 347
 348/*
 349 * get an AFS superblock
 350 */
 351static struct dentry *afs_mount(struct file_system_type *fs_type,
 352                      int flags, const char *dev_name, void *options)
 353{
 354        struct afs_mount_params params;
 355        struct super_block *sb;
 356        struct afs_volume *vol;
 357        struct key *key;
 358        char *new_opts = kstrdup(options, GFP_KERNEL);
 359        struct afs_super_info *as;
 360        int ret;
 361
 362        _enter(",,%s,%p", dev_name, options);
 363
 364        memset(&params, 0, sizeof(params));
 365
 366        /* parse the options and device name */
 367        if (options) {
 368                ret = afs_parse_options(&params, options, &dev_name);
 369                if (ret < 0)
 370                        goto error;
 371        }
 372
 373        ret = afs_parse_device_name(&params, dev_name);
 374        if (ret < 0)
 375                goto error;
 376
 377        /* try and do the mount securely */
 378        key = afs_request_key(params.cell);
 379        if (IS_ERR(key)) {
 380                _leave(" = %ld [key]", PTR_ERR(key));
 381                ret = PTR_ERR(key);
 382                goto error;
 383        }
 384        params.key = key;
 385
 386        /* parse the device name */
 387        vol = afs_volume_lookup(&params);
 388        if (IS_ERR(vol)) {
 389                ret = PTR_ERR(vol);
 390                goto error;
 391        }
 392
 393        /* allocate a superblock info record */
 394        as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 395        if (!as) {
 396                ret = -ENOMEM;
 397                afs_put_volume(vol);
 398                goto error;
 399        }
 400        as->volume = vol;
 401
 402        /* allocate a deviceless superblock */
 403        sb = sget(fs_type, afs_test_super, afs_set_super, flags, as);
 404        if (IS_ERR(sb)) {
 405                ret = PTR_ERR(sb);
 406                afs_put_volume(vol);
 407                kfree(as);
 408                goto error;
 409        }
 410
 411        if (!sb->s_root) {
 412                /* initial superblock/root creation */
 413                _debug("create");
 414                ret = afs_fill_super(sb, &params);
 415                if (ret < 0) {
 416                        deactivate_locked_super(sb);
 417                        goto error;
 418                }
 419                save_mount_options(sb, new_opts);
 420                sb->s_flags |= MS_ACTIVE;
 421        } else {
 422                _debug("reuse");
 423                ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 424                afs_put_volume(vol);
 425                kfree(as);
 426        }
 427
 428        afs_put_cell(params.cell);
 429        kfree(new_opts);
 430        _leave(" = 0 [%p]", sb);
 431        return dget(sb->s_root);
 432
 433error:
 434        afs_put_cell(params.cell);
 435        key_put(params.key);
 436        kfree(new_opts);
 437        _leave(" = %d", ret);
 438        return ERR_PTR(ret);
 439}
 440
 441static void afs_kill_super(struct super_block *sb)
 442{
 443        struct afs_super_info *as = sb->s_fs_info;
 444        kill_anon_super(sb);
 445        afs_put_volume(as->volume);
 446        kfree(as);
 447}
 448
 449/*
 450 * initialise an inode cache slab element prior to any use
 451 */
 452static void afs_i_init_once(void *_vnode)
 453{
 454        struct afs_vnode *vnode = _vnode;
 455
 456        memset(vnode, 0, sizeof(*vnode));
 457        inode_init_once(&vnode->vfs_inode);
 458        init_waitqueue_head(&vnode->update_waitq);
 459        mutex_init(&vnode->permits_lock);
 460        mutex_init(&vnode->validate_lock);
 461        spin_lock_init(&vnode->writeback_lock);
 462        spin_lock_init(&vnode->lock);
 463        INIT_LIST_HEAD(&vnode->writebacks);
 464        INIT_LIST_HEAD(&vnode->pending_locks);
 465        INIT_LIST_HEAD(&vnode->granted_locks);
 466        INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 467        INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 468}
 469
 470/*
 471 * allocate an AFS inode struct from our slab cache
 472 */
 473static struct inode *afs_alloc_inode(struct super_block *sb)
 474{
 475        struct afs_vnode *vnode;
 476
 477        vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 478        if (!vnode)
 479                return NULL;
 480
 481        atomic_inc(&afs_count_active_inodes);
 482
 483        memset(&vnode->fid, 0, sizeof(vnode->fid));
 484        memset(&vnode->status, 0, sizeof(vnode->status));
 485
 486        vnode->volume           = NULL;
 487        vnode->update_cnt       = 0;
 488        vnode->flags            = 1 << AFS_VNODE_UNSET;
 489        vnode->cb_promised      = false;
 490
 491        _leave(" = %p", &vnode->vfs_inode);
 492        return &vnode->vfs_inode;
 493}
 494
 495static void afs_i_callback(struct rcu_head *head)
 496{
 497        struct inode *inode = container_of(head, struct inode, i_rcu);
 498        struct afs_vnode *vnode = AFS_FS_I(inode);
 499        kmem_cache_free(afs_inode_cachep, vnode);
 500}
 501
 502/*
 503 * destroy an AFS inode struct
 504 */
 505static void afs_destroy_inode(struct inode *inode)
 506{
 507        struct afs_vnode *vnode = AFS_FS_I(inode);
 508
 509        _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 510
 511        _debug("DESTROY INODE %p", inode);
 512
 513        ASSERTCMP(vnode->server, ==, NULL);
 514
 515        call_rcu(&inode->i_rcu, afs_i_callback);
 516        atomic_dec(&afs_count_active_inodes);
 517}
 518
 519/*
 520 * return information about an AFS volume
 521 */
 522static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 523{
 524        struct afs_volume_status vs;
 525        struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 526        struct key *key;
 527        int ret;
 528
 529        key = afs_request_key(vnode->volume->cell);
 530        if (IS_ERR(key))
 531                return PTR_ERR(key);
 532
 533        ret = afs_vnode_get_volume_status(vnode, key, &vs);
 534        key_put(key);
 535        if (ret < 0) {
 536                _leave(" = %d", ret);
 537                return ret;
 538        }
 539
 540        buf->f_type     = dentry->d_sb->s_magic;
 541        buf->f_bsize    = AFS_BLOCK_SIZE;
 542        buf->f_namelen  = AFSNAMEMAX - 1;
 543
 544        if (vs.max_quota == 0)
 545                buf->f_blocks = vs.part_max_blocks;
 546        else
 547                buf->f_blocks = vs.max_quota;
 548        buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 549        return 0;
 550}
 551
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.