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 <linux/nsproxy.h>
  28#include <net/net_namespace.h>
  29#include "internal.h"
  30
  31#define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
  32
  33static void afs_i_init_once(void *foo);
  34static struct dentry *afs_mount(struct file_system_type *fs_type,
  35                      int flags, const char *dev_name, void *data);
  36static void afs_kill_super(struct super_block *sb);
  37static struct inode *afs_alloc_inode(struct super_block *sb);
  38static void afs_destroy_inode(struct inode *inode);
  39static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
  40
  41struct file_system_type afs_fs_type = {
  42        .owner          = THIS_MODULE,
  43        .name           = "afs",
  44        .mount          = afs_mount,
  45        .kill_sb        = afs_kill_super,
  46        .fs_flags       = 0,
  47};
  48MODULE_ALIAS_FS("afs");
  49
  50static const struct super_operations afs_super_ops = {
  51        .statfs         = afs_statfs,
  52        .alloc_inode    = afs_alloc_inode,
  53        .drop_inode     = afs_drop_inode,
  54        .destroy_inode  = afs_destroy_inode,
  55        .evict_inode    = afs_evict_inode,
  56        .show_options   = generic_show_options,
  57};
  58
  59static struct kmem_cache *afs_inode_cachep;
  60static atomic_t afs_count_active_inodes;
  61
  62enum {
  63        afs_no_opt,
  64        afs_opt_cell,
  65        afs_opt_rwpath,
  66        afs_opt_vol,
  67        afs_opt_autocell,
  68};
  69
  70static const match_table_t afs_options_list = {
  71        { afs_opt_cell,         "cell=%s"       },
  72        { afs_opt_rwpath,       "rwpath"        },
  73        { afs_opt_vol,          "vol=%s"        },
  74        { afs_opt_autocell,     "autocell"      },
  75        { afs_no_opt,           NULL            },
  76};
  77
  78/*
  79 * initialise the filesystem
  80 */
  81int __init afs_fs_init(void)
  82{
  83        int ret;
  84
  85        _enter("");
  86
  87        /* create ourselves an inode cache */
  88        atomic_set(&afs_count_active_inodes, 0);
  89
  90        ret = -ENOMEM;
  91        afs_inode_cachep = kmem_cache_create("afs_inode_cache",
  92                                             sizeof(struct afs_vnode),
  93                                             0,
  94                                             SLAB_HWCACHE_ALIGN,
  95                                             afs_i_init_once);
  96        if (!afs_inode_cachep) {
  97                printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
  98                return ret;
  99        }
 100
 101        /* now export our filesystem to lesser mortals */
 102        ret = register_filesystem(&afs_fs_type);
 103        if (ret < 0) {
 104                kmem_cache_destroy(afs_inode_cachep);
 105                _leave(" = %d", ret);
 106                return ret;
 107        }
 108
 109        _leave(" = 0");
 110        return 0;
 111}
 112
 113/*
 114 * clean up the filesystem
 115 */
 116void __exit afs_fs_exit(void)
 117{
 118        _enter("");
 119
 120        afs_mntpt_kill_timer();
 121        unregister_filesystem(&afs_fs_type);
 122
 123        if (atomic_read(&afs_count_active_inodes) != 0) {
 124                printk("kAFS: %d active inode objects still present\n",
 125                       atomic_read(&afs_count_active_inodes));
 126                BUG();
 127        }
 128
 129        /*
 130         * Make sure all delayed rcu free inodes are flushed before we
 131         * destroy cache.
 132         */
 133        rcu_barrier();
 134        kmem_cache_destroy(afs_inode_cachep);
 135        _leave("");
 136}
 137
 138/*
 139 * parse the mount options
 140 * - this function has been shamelessly adapted from the ext3 fs which
 141 *   shamelessly adapted it from the msdos fs
 142 */
 143static int afs_parse_options(struct afs_mount_params *params,
 144                             char *options, const char **devname)
 145{
 146        struct afs_cell *cell;
 147        substring_t args[MAX_OPT_ARGS];
 148        char *p;
 149        int token;
 150
 151        _enter("%s", options);
 152
 153        options[PAGE_SIZE - 1] = 0;
 154
 155        while ((p = strsep(&options, ","))) {
 156                if (!*p)
 157                        continue;
 158
 159                token = match_token(p, afs_options_list, args);
 160                switch (token) {
 161                case afs_opt_cell:
 162                        cell = afs_cell_lookup(args[0].from,
 163                                               args[0].to - args[0].from,
 164                                               false);
 165                        if (IS_ERR(cell))
 166                                return PTR_ERR(cell);
 167                        afs_put_cell(params->cell);
 168                        params->cell = cell;
 169                        break;
 170
 171                case afs_opt_rwpath:
 172                        params->rwpath = 1;
 173                        break;
 174
 175                case afs_opt_vol:
 176                        *devname = args[0].from;
 177                        break;
 178
 179                case afs_opt_autocell:
 180                        params->autocell = 1;
 181                        break;
 182
 183                default:
 184                        printk(KERN_ERR "kAFS:"
 185                               " Unknown or invalid mount option: '%s'\n", p);
 186                        return -EINVAL;
 187                }
 188        }
 189
 190        _leave(" = 0");
 191        return 0;
 192}
 193
 194/*
 195 * parse a device name to get cell name, volume name, volume type and R/W
 196 * selector
 197 * - this can be one of the following:
 198 *      "%[cell:]volume[.]"             R/W volume
 199 *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 200 *                                       or R/W (rwpath=1) volume
 201 *      "%[cell:]volume.readonly"       R/O volume
 202 *      "#[cell:]volume.readonly"       R/O volume
 203 *      "%[cell:]volume.backup"         Backup volume
 204 *      "#[cell:]volume.backup"         Backup volume
 205 */
 206static int afs_parse_device_name(struct afs_mount_params *params,
 207                                 const char *name)
 208{
 209        struct afs_cell *cell;
 210        const char *cellname, *suffix;
 211        int cellnamesz;
 212
 213        _enter(",%s", name);
 214
 215        if (!name) {
 216                printk(KERN_ERR "kAFS: no volume name specified\n");
 217                return -EINVAL;
 218        }
 219
 220        if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 221                printk(KERN_ERR "kAFS: unparsable volume name\n");
 222                return -EINVAL;
 223        }
 224
 225        /* determine the type of volume we're looking for */
 226        params->type = AFSVL_ROVOL;
 227        params->force = false;
 228        if (params->rwpath || name[0] == '%') {
 229                params->type = AFSVL_RWVOL;
 230                params->force = true;
 231        }
 232        name++;
 233
 234        /* split the cell name out if there is one */
 235        params->volname = strchr(name, ':');
 236        if (params->volname) {
 237                cellname = name;
 238                cellnamesz = params->volname - name;
 239                params->volname++;
 240        } else {
 241                params->volname = name;
 242                cellname = NULL;
 243                cellnamesz = 0;
 244        }
 245
 246        /* the volume type is further affected by a possible suffix */
 247        suffix = strrchr(params->volname, '.');
 248        if (suffix) {
 249                if (strcmp(suffix, ".readonly") == 0) {
 250                        params->type = AFSVL_ROVOL;
 251                        params->force = true;
 252                } else if (strcmp(suffix, ".backup") == 0) {
 253                        params->type = AFSVL_BACKVOL;
 254                        params->force = true;
 255                } else if (suffix[1] == 0) {
 256                } else {
 257                        suffix = NULL;
 258                }
 259        }
 260
 261        params->volnamesz = suffix ?
 262                suffix - params->volname : strlen(params->volname);
 263
 264        _debug("cell %*.*s [%p]",
 265               cellnamesz, cellnamesz, cellname ?: "", params->cell);
 266
 267        /* lookup the cell record */
 268        if (cellname || !params->cell) {
 269                cell = afs_cell_lookup(cellname, cellnamesz, true);
 270                if (IS_ERR(cell)) {
 271                        printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
 272                               cellnamesz, cellnamesz, cellname ?: "");
 273                        return PTR_ERR(cell);
 274                }
 275                afs_put_cell(params->cell);
 276                params->cell = cell;
 277        }
 278
 279        _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 280               params->cell->name, params->cell,
 281               params->volnamesz, params->volnamesz, params->volname,
 282               suffix ?: "-", params->type, params->force ? " FORCE" : "");
 283
 284        return 0;
 285}
 286
 287/*
 288 * check a superblock to see if it's the one we're looking for
 289 */
 290static int afs_test_super(struct super_block *sb, void *data)
 291{
 292        struct afs_super_info *as1 = data;
 293        struct afs_super_info *as = sb->s_fs_info;
 294
 295        return as->volume == as1->volume;
 296}
 297
 298static int afs_set_super(struct super_block *sb, void *data)
 299{
 300        sb->s_fs_info = data;
 301        return set_anon_super(sb, NULL);
 302}
 303
 304/*
 305 * fill in the superblock
 306 */
 307static int afs_fill_super(struct super_block *sb,
 308                          struct afs_mount_params *params)
 309{
 310        struct afs_super_info *as = sb->s_fs_info;
 311        struct afs_fid fid;
 312        struct inode *inode = NULL;
 313        int ret;
 314
 315        _enter("");
 316
 317        /* fill in the superblock */
 318        sb->s_blocksize         = PAGE_CACHE_SIZE;
 319        sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 320        sb->s_magic             = AFS_FS_MAGIC;
 321        sb->s_op                = &afs_super_ops;
 322        sb->s_bdi               = &as->volume->bdi;
 323        strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
 324
 325        /* allocate the root inode and dentry */
 326        fid.vid         = as->volume->vid;
 327        fid.vnode       = 1;
 328        fid.unique      = 1;
 329        inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 330        if (IS_ERR(inode))
 331                return PTR_ERR(inode);
 332
 333        if (params->autocell)
 334                set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 335
 336        ret = -ENOMEM;
 337        sb->s_root = d_make_root(inode);
 338        if (!sb->s_root)
 339                goto error;
 340
 341        sb->s_d_op = &afs_fs_dentry_operations;
 342
 343        _leave(" = 0");
 344        return 0;
 345
 346error:
 347        _leave(" = %d", ret);
 348        return ret;
 349}
 350
 351/*
 352 * get an AFS superblock
 353 */
 354static struct dentry *afs_mount(struct file_system_type *fs_type,
 355                      int flags, const char *dev_name, void *options)
 356{
 357        struct afs_mount_params params;
 358        struct super_block *sb;
 359        struct afs_volume *vol;
 360        struct key *key;
 361        char *new_opts = kstrdup(options, GFP_KERNEL);
 362        struct afs_super_info *as;
 363        int ret;
 364
 365        _enter(",,%s,%p", dev_name, options);
 366
 367        memset(&params, 0, sizeof(params));
 368
 369        ret = -EINVAL;
 370        if (current->nsproxy->net_ns != &init_net)
 371                goto error;
 372
 373        /* parse the options and device name */
 374        if (options) {
 375                ret = afs_parse_options(&params, options, &dev_name);
 376                if (ret < 0)
 377                        goto error;
 378        }
 379
 380        ret = afs_parse_device_name(&params, dev_name);
 381        if (ret < 0)
 382                goto error;
 383
 384        /* try and do the mount securely */
 385        key = afs_request_key(params.cell);
 386        if (IS_ERR(key)) {
 387                _leave(" = %ld [key]", PTR_ERR(key));
 388                ret = PTR_ERR(key);
 389                goto error;
 390        }
 391        params.key = key;
 392
 393        /* parse the device name */
 394        vol = afs_volume_lookup(&params);
 395        if (IS_ERR(vol)) {
 396                ret = PTR_ERR(vol);
 397                goto error;
 398        }
 399
 400        /* allocate a superblock info record */
 401        as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 402        if (!as) {
 403                ret = -ENOMEM;
 404                afs_put_volume(vol);
 405                goto error;
 406        }
 407        as->volume = vol;
 408
 409        /* allocate a deviceless superblock */
 410        sb = sget(fs_type, afs_test_super, afs_set_super, flags, as);
 411        if (IS_ERR(sb)) {
 412                ret = PTR_ERR(sb);
 413                afs_put_volume(vol);
 414                kfree(as);
 415                goto error;
 416        }
 417
 418        if (!sb->s_root) {
 419                /* initial superblock/root creation */
 420                _debug("create");
 421                ret = afs_fill_super(sb, &params);
 422                if (ret < 0) {
 423                        deactivate_locked_super(sb);
 424                        goto error;
 425                }
 426                save_mount_options(sb, new_opts);
 427                sb->s_flags |= MS_ACTIVE;
 428        } else {
 429                _debug("reuse");
 430                ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 431                afs_put_volume(vol);
 432                kfree(as);
 433        }
 434
 435        afs_put_cell(params.cell);
 436        kfree(new_opts);
 437        _leave(" = 0 [%p]", sb);
 438        return dget(sb->s_root);
 439
 440error:
 441        afs_put_cell(params.cell);
 442        key_put(params.key);
 443        kfree(new_opts);
 444        _leave(" = %d", ret);
 445        return ERR_PTR(ret);
 446}
 447
 448static void afs_kill_super(struct super_block *sb)
 449{
 450        struct afs_super_info *as = sb->s_fs_info;
 451        kill_anon_super(sb);
 452        afs_put_volume(as->volume);
 453        kfree(as);
 454}
 455
 456/*
 457 * initialise an inode cache slab element prior to any use
 458 */
 459static void afs_i_init_once(void *_vnode)
 460{
 461        struct afs_vnode *vnode = _vnode;
 462
 463        memset(vnode, 0, sizeof(*vnode));
 464        inode_init_once(&vnode->vfs_inode);
 465        init_waitqueue_head(&vnode->update_waitq);
 466        mutex_init(&vnode->permits_lock);
 467        mutex_init(&vnode->validate_lock);
 468        spin_lock_init(&vnode->writeback_lock);
 469        spin_lock_init(&vnode->lock);
 470        INIT_LIST_HEAD(&vnode->writebacks);
 471        INIT_LIST_HEAD(&vnode->pending_locks);
 472        INIT_LIST_HEAD(&vnode->granted_locks);
 473        INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 474        INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 475}
 476
 477/*
 478 * allocate an AFS inode struct from our slab cache
 479 */
 480static struct inode *afs_alloc_inode(struct super_block *sb)
 481{
 482        struct afs_vnode *vnode;
 483
 484        vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 485        if (!vnode)
 486                return NULL;
 487
 488        atomic_inc(&afs_count_active_inodes);
 489
 490        memset(&vnode->fid, 0, sizeof(vnode->fid));
 491        memset(&vnode->status, 0, sizeof(vnode->status));
 492
 493        vnode->volume           = NULL;
 494        vnode->update_cnt       = 0;
 495        vnode->flags            = 1 << AFS_VNODE_UNSET;
 496        vnode->cb_promised      = false;
 497
 498        _leave(" = %p", &vnode->vfs_inode);
 499        return &vnode->vfs_inode;
 500}
 501
 502static void afs_i_callback(struct rcu_head *head)
 503{
 504        struct inode *inode = container_of(head, struct inode, i_rcu);
 505        struct afs_vnode *vnode = AFS_FS_I(inode);
 506        kmem_cache_free(afs_inode_cachep, vnode);
 507}
 508
 509/*
 510 * destroy an AFS inode struct
 511 */
 512static void afs_destroy_inode(struct inode *inode)
 513{
 514        struct afs_vnode *vnode = AFS_FS_I(inode);
 515
 516        _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 517
 518        _debug("DESTROY INODE %p", inode);
 519
 520        ASSERTCMP(vnode->server, ==, NULL);
 521
 522        call_rcu(&inode->i_rcu, afs_i_callback);
 523        atomic_dec(&afs_count_active_inodes);
 524}
 525
 526/*
 527 * return information about an AFS volume
 528 */
 529static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 530{
 531        struct afs_volume_status vs;
 532        struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 533        struct key *key;
 534        int ret;
 535
 536        key = afs_request_key(vnode->volume->cell);
 537        if (IS_ERR(key))
 538                return PTR_ERR(key);
 539
 540        ret = afs_vnode_get_volume_status(vnode, key, &vs);
 541        key_put(key);
 542        if (ret < 0) {
 543                _leave(" = %d", ret);
 544                return ret;
 545        }
 546
 547        buf->f_type     = dentry->d_sb->s_magic;
 548        buf->f_bsize    = AFS_BLOCK_SIZE;
 549        buf->f_namelen  = AFSNAMEMAX - 1;
 550
 551        if (vs.max_quota == 0)
 552                buf->f_blocks = vs.part_max_blocks;
 553        else
 554                buf->f_blocks = vs.max_quota;
 555        buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 556        return 0;
 557}
 558
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.