linux/fs/afs/super.c
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   1/* AFS superblock handling
   2 *
   3 * Copyright (c) 2002, 2007, 2018 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/fs_parser.h>
  25#include <linux/statfs.h>
  26#include <linux/sched.h>
  27#include <linux/nsproxy.h>
  28#include <linux/magic.h>
  29#include <net/net_namespace.h>
  30#include "internal.h"
  31
  32static void afs_i_init_once(void *foo);
  33static void afs_kill_super(struct super_block *sb);
  34static struct inode *afs_alloc_inode(struct super_block *sb);
  35static void afs_destroy_inode(struct inode *inode);
  36static void afs_free_inode(struct inode *inode);
  37static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
  38static int afs_show_devname(struct seq_file *m, struct dentry *root);
  39static int afs_show_options(struct seq_file *m, struct dentry *root);
  40static int afs_init_fs_context(struct fs_context *fc);
  41static const struct fs_parameter_spec afs_fs_parameters[];
  42
  43struct file_system_type afs_fs_type = {
  44        .owner                  = THIS_MODULE,
  45        .name                   = "afs",
  46        .init_fs_context        = afs_init_fs_context,
  47        .parameters             = afs_fs_parameters,
  48        .kill_sb                = afs_kill_super,
  49        .fs_flags               = FS_RENAME_DOES_D_MOVE,
  50};
  51MODULE_ALIAS_FS("afs");
  52
  53int afs_net_id;
  54
  55static const struct super_operations afs_super_ops = {
  56        .statfs         = afs_statfs,
  57        .alloc_inode    = afs_alloc_inode,
  58        .drop_inode     = afs_drop_inode,
  59        .destroy_inode  = afs_destroy_inode,
  60        .free_inode     = afs_free_inode,
  61        .evict_inode    = afs_evict_inode,
  62        .show_devname   = afs_show_devname,
  63        .show_options   = afs_show_options,
  64};
  65
  66static struct kmem_cache *afs_inode_cachep;
  67static atomic_t afs_count_active_inodes;
  68
  69enum afs_param {
  70        Opt_autocell,
  71        Opt_dyn,
  72        Opt_flock,
  73        Opt_source,
  74};
  75
  76static const struct constant_table afs_param_flock[] = {
  77        {"local",       afs_flock_mode_local },
  78        {"openafs",     afs_flock_mode_openafs },
  79        {"strict",      afs_flock_mode_strict },
  80        {"write",       afs_flock_mode_write },
  81        {}
  82};
  83
  84static const struct fs_parameter_spec afs_fs_parameters[] = {
  85        fsparam_flag  ("autocell",      Opt_autocell),
  86        fsparam_flag  ("dyn",           Opt_dyn),
  87        fsparam_enum  ("flock",         Opt_flock, afs_param_flock),
  88        fsparam_string("source",        Opt_source),
  89        {}
  90};
  91
  92/*
  93 * initialise the filesystem
  94 */
  95int __init afs_fs_init(void)
  96{
  97        int ret;
  98
  99        _enter("");
 100
 101        /* create ourselves an inode cache */
 102        atomic_set(&afs_count_active_inodes, 0);
 103
 104        ret = -ENOMEM;
 105        afs_inode_cachep = kmem_cache_create("afs_inode_cache",
 106                                             sizeof(struct afs_vnode),
 107                                             0,
 108                                             SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
 109                                             afs_i_init_once);
 110        if (!afs_inode_cachep) {
 111                printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
 112                return ret;
 113        }
 114
 115        /* now export our filesystem to lesser mortals */
 116        ret = register_filesystem(&afs_fs_type);
 117        if (ret < 0) {
 118                kmem_cache_destroy(afs_inode_cachep);
 119                _leave(" = %d", ret);
 120                return ret;
 121        }
 122
 123        _leave(" = 0");
 124        return 0;
 125}
 126
 127/*
 128 * clean up the filesystem
 129 */
 130void afs_fs_exit(void)
 131{
 132        _enter("");
 133
 134        afs_mntpt_kill_timer();
 135        unregister_filesystem(&afs_fs_type);
 136
 137        if (atomic_read(&afs_count_active_inodes) != 0) {
 138                printk("kAFS: %d active inode objects still present\n",
 139                       atomic_read(&afs_count_active_inodes));
 140                BUG();
 141        }
 142
 143        /*
 144         * Make sure all delayed rcu free inodes are flushed before we
 145         * destroy cache.
 146         */
 147        rcu_barrier();
 148        kmem_cache_destroy(afs_inode_cachep);
 149        _leave("");
 150}
 151
 152/*
 153 * Display the mount device name in /proc/mounts.
 154 */
 155static int afs_show_devname(struct seq_file *m, struct dentry *root)
 156{
 157        struct afs_super_info *as = AFS_FS_S(root->d_sb);
 158        struct afs_volume *volume = as->volume;
 159        struct afs_cell *cell = as->cell;
 160        const char *suf = "";
 161        char pref = '%';
 162
 163        if (as->dyn_root) {
 164                seq_puts(m, "none");
 165                return 0;
 166        }
 167
 168        switch (volume->type) {
 169        case AFSVL_RWVOL:
 170                break;
 171        case AFSVL_ROVOL:
 172                pref = '#';
 173                if (volume->type_force)
 174                        suf = ".readonly";
 175                break;
 176        case AFSVL_BACKVOL:
 177                pref = '#';
 178                suf = ".backup";
 179                break;
 180        }
 181
 182        seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
 183        return 0;
 184}
 185
 186/*
 187 * Display the mount options in /proc/mounts.
 188 */
 189static int afs_show_options(struct seq_file *m, struct dentry *root)
 190{
 191        struct afs_super_info *as = AFS_FS_S(root->d_sb);
 192        const char *p = NULL;
 193
 194        if (as->dyn_root)
 195                seq_puts(m, ",dyn");
 196        if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
 197                seq_puts(m, ",autocell");
 198        switch (as->flock_mode) {
 199        case afs_flock_mode_unset:      break;
 200        case afs_flock_mode_local:      p = "local";    break;
 201        case afs_flock_mode_openafs:    p = "openafs";  break;
 202        case afs_flock_mode_strict:     p = "strict";   break;
 203        case afs_flock_mode_write:      p = "write";    break;
 204        }
 205        if (p)
 206                seq_printf(m, ",flock=%s", p);
 207
 208        return 0;
 209}
 210
 211/*
 212 * Parse the source name to get cell name, volume name, volume type and R/W
 213 * selector.
 214 *
 215 * This can be one of the following:
 216 *      "%[cell:]volume[.]"             R/W volume
 217 *      "#[cell:]volume[.]"             R/O or R/W volume (R/O parent),
 218 *                                       or R/W (R/W parent) volume
 219 *      "%[cell:]volume.readonly"       R/O volume
 220 *      "#[cell:]volume.readonly"       R/O volume
 221 *      "%[cell:]volume.backup"         Backup volume
 222 *      "#[cell:]volume.backup"         Backup volume
 223 */
 224static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
 225{
 226        struct afs_fs_context *ctx = fc->fs_private;
 227        struct afs_cell *cell;
 228        const char *cellname, *suffix, *name = param->string;
 229        int cellnamesz;
 230
 231        _enter(",%s", name);
 232
 233        if (fc->source)
 234                return invalf(fc, "kAFS: Multiple sources not supported");
 235
 236        if (!name) {
 237                printk(KERN_ERR "kAFS: no volume name specified\n");
 238                return -EINVAL;
 239        }
 240
 241        if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 242                /* To use dynroot, we don't want to have to provide a source */
 243                if (strcmp(name, "none") == 0) {
 244                        ctx->no_cell = true;
 245                        return 0;
 246                }
 247                printk(KERN_ERR "kAFS: unparsable volume name\n");
 248                return -EINVAL;
 249        }
 250
 251        /* determine the type of volume we're looking for */
 252        if (name[0] == '%') {
 253                ctx->type = AFSVL_RWVOL;
 254                ctx->force = true;
 255        }
 256        name++;
 257
 258        /* split the cell name out if there is one */
 259        ctx->volname = strchr(name, ':');
 260        if (ctx->volname) {
 261                cellname = name;
 262                cellnamesz = ctx->volname - name;
 263                ctx->volname++;
 264        } else {
 265                ctx->volname = name;
 266                cellname = NULL;
 267                cellnamesz = 0;
 268        }
 269
 270        /* the volume type is further affected by a possible suffix */
 271        suffix = strrchr(ctx->volname, '.');
 272        if (suffix) {
 273                if (strcmp(suffix, ".readonly") == 0) {
 274                        ctx->type = AFSVL_ROVOL;
 275                        ctx->force = true;
 276                } else if (strcmp(suffix, ".backup") == 0) {
 277                        ctx->type = AFSVL_BACKVOL;
 278                        ctx->force = true;
 279                } else if (suffix[1] == 0) {
 280                } else {
 281                        suffix = NULL;
 282                }
 283        }
 284
 285        ctx->volnamesz = suffix ?
 286                suffix - ctx->volname : strlen(ctx->volname);
 287
 288        _debug("cell %*.*s [%p]",
 289               cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
 290
 291        /* lookup the cell record */
 292        if (cellname) {
 293                cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
 294                                       NULL, false);
 295                if (IS_ERR(cell)) {
 296                        pr_err("kAFS: unable to lookup cell '%*.*s'\n",
 297                               cellnamesz, cellnamesz, cellname ?: "");
 298                        return PTR_ERR(cell);
 299                }
 300                afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_parse);
 301                afs_see_cell(cell, afs_cell_trace_see_source);
 302                ctx->cell = cell;
 303        }
 304
 305        _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 306               ctx->cell->name, ctx->cell,
 307               ctx->volnamesz, ctx->volnamesz, ctx->volname,
 308               suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
 309
 310        fc->source = param->string;
 311        param->string = NULL;
 312        return 0;
 313}
 314
 315/*
 316 * Parse a single mount parameter.
 317 */
 318static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 319{
 320        struct fs_parse_result result;
 321        struct afs_fs_context *ctx = fc->fs_private;
 322        int opt;
 323
 324        opt = fs_parse(fc, afs_fs_parameters, param, &result);
 325        if (opt < 0)
 326                return opt;
 327
 328        switch (opt) {
 329        case Opt_source:
 330                return afs_parse_source(fc, param);
 331
 332        case Opt_autocell:
 333                ctx->autocell = true;
 334                break;
 335
 336        case Opt_dyn:
 337                ctx->dyn_root = true;
 338                break;
 339
 340        case Opt_flock:
 341                ctx->flock_mode = result.uint_32;
 342                break;
 343
 344        default:
 345                return -EINVAL;
 346        }
 347
 348        _leave(" = 0");
 349        return 0;
 350}
 351
 352/*
 353 * Validate the options, get the cell key and look up the volume.
 354 */
 355static int afs_validate_fc(struct fs_context *fc)
 356{
 357        struct afs_fs_context *ctx = fc->fs_private;
 358        struct afs_volume *volume;
 359        struct afs_cell *cell;
 360        struct key *key;
 361        int ret;
 362
 363        if (!ctx->dyn_root) {
 364                if (ctx->no_cell) {
 365                        pr_warn("kAFS: Can only specify source 'none' with -o dyn\n");
 366                        return -EINVAL;
 367                }
 368
 369                if (!ctx->cell) {
 370                        pr_warn("kAFS: No cell specified\n");
 371                        return -EDESTADDRREQ;
 372                }
 373
 374        reget_key:
 375                /* We try to do the mount securely. */
 376                key = afs_request_key(ctx->cell);
 377                if (IS_ERR(key))
 378                        return PTR_ERR(key);
 379
 380                ctx->key = key;
 381
 382                if (ctx->volume) {
 383                        afs_put_volume(ctx->net, ctx->volume,
 384                                       afs_volume_trace_put_validate_fc);
 385                        ctx->volume = NULL;
 386                }
 387
 388                if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &ctx->cell->flags)) {
 389                        ret = afs_cell_detect_alias(ctx->cell, key);
 390                        if (ret < 0)
 391                                return ret;
 392                        if (ret == 1) {
 393                                _debug("switch to alias");
 394                                key_put(ctx->key);
 395                                ctx->key = NULL;
 396                                cell = afs_use_cell(ctx->cell->alias_of,
 397                                                    afs_cell_trace_use_fc_alias);
 398                                afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
 399                                ctx->cell = cell;
 400                                goto reget_key;
 401                        }
 402                }
 403
 404                volume = afs_create_volume(ctx);
 405                if (IS_ERR(volume))
 406                        return PTR_ERR(volume);
 407
 408                ctx->volume = volume;
 409        }
 410
 411        return 0;
 412}
 413
 414/*
 415 * check a superblock to see if it's the one we're looking for
 416 */
 417static int afs_test_super(struct super_block *sb, struct fs_context *fc)
 418{
 419        struct afs_fs_context *ctx = fc->fs_private;
 420        struct afs_super_info *as = AFS_FS_S(sb);
 421
 422        return (as->net_ns == fc->net_ns &&
 423                as->volume &&
 424                as->volume->vid == ctx->volume->vid &&
 425                as->cell == ctx->cell &&
 426                !as->dyn_root);
 427}
 428
 429static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
 430{
 431        struct afs_super_info *as = AFS_FS_S(sb);
 432
 433        return (as->net_ns == fc->net_ns &&
 434                as->dyn_root);
 435}
 436
 437static int afs_set_super(struct super_block *sb, struct fs_context *fc)
 438{
 439        return set_anon_super(sb, NULL);
 440}
 441
 442/*
 443 * fill in the superblock
 444 */
 445static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
 446{
 447        struct afs_super_info *as = AFS_FS_S(sb);
 448        struct inode *inode = NULL;
 449        int ret;
 450
 451        _enter("");
 452
 453        /* fill in the superblock */
 454        sb->s_blocksize         = PAGE_SIZE;
 455        sb->s_blocksize_bits    = PAGE_SHIFT;
 456        sb->s_maxbytes          = MAX_LFS_FILESIZE;
 457        sb->s_magic             = AFS_FS_MAGIC;
 458        sb->s_op                = &afs_super_ops;
 459        if (!as->dyn_root)
 460                sb->s_xattr     = afs_xattr_handlers;
 461        ret = super_setup_bdi(sb);
 462        if (ret)
 463                return ret;
 464
 465        /* allocate the root inode and dentry */
 466        if (as->dyn_root) {
 467                inode = afs_iget_pseudo_dir(sb, true);
 468        } else {
 469                sprintf(sb->s_id, "%llu", as->volume->vid);
 470                afs_activate_volume(as->volume);
 471                inode = afs_root_iget(sb, ctx->key);
 472        }
 473
 474        if (IS_ERR(inode))
 475                return PTR_ERR(inode);
 476
 477        if (ctx->autocell || as->dyn_root)
 478                set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 479
 480        ret = -ENOMEM;
 481        sb->s_root = d_make_root(inode);
 482        if (!sb->s_root)
 483                goto error;
 484
 485        if (as->dyn_root) {
 486                sb->s_d_op = &afs_dynroot_dentry_operations;
 487                ret = afs_dynroot_populate(sb);
 488                if (ret < 0)
 489                        goto error;
 490        } else {
 491                sb->s_d_op = &afs_fs_dentry_operations;
 492                rcu_assign_pointer(as->volume->sb, sb);
 493        }
 494
 495        _leave(" = 0");
 496        return 0;
 497
 498error:
 499        _leave(" = %d", ret);
 500        return ret;
 501}
 502
 503static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
 504{
 505        struct afs_fs_context *ctx = fc->fs_private;
 506        struct afs_super_info *as;
 507
 508        as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 509        if (as) {
 510                as->net_ns = get_net(fc->net_ns);
 511                as->flock_mode = ctx->flock_mode;
 512                if (ctx->dyn_root) {
 513                        as->dyn_root = true;
 514                } else {
 515                        as->cell = afs_use_cell(ctx->cell, afs_cell_trace_use_sbi);
 516                        as->volume = afs_get_volume(ctx->volume,
 517                                                    afs_volume_trace_get_alloc_sbi);
 518                }
 519        }
 520        return as;
 521}
 522
 523static void afs_destroy_sbi(struct afs_super_info *as)
 524{
 525        if (as) {
 526                struct afs_net *net = afs_net(as->net_ns);
 527                afs_put_volume(net, as->volume, afs_volume_trace_put_destroy_sbi);
 528                afs_unuse_cell(net, as->cell, afs_cell_trace_unuse_sbi);
 529                put_net(as->net_ns);
 530                kfree(as);
 531        }
 532}
 533
 534static void afs_kill_super(struct super_block *sb)
 535{
 536        struct afs_super_info *as = AFS_FS_S(sb);
 537
 538        if (as->dyn_root)
 539                afs_dynroot_depopulate(sb);
 540
 541        /* Clear the callback interests (which will do ilookup5) before
 542         * deactivating the superblock.
 543         */
 544        if (as->volume)
 545                rcu_assign_pointer(as->volume->sb, NULL);
 546        kill_anon_super(sb);
 547        if (as->volume)
 548                afs_deactivate_volume(as->volume);
 549        afs_destroy_sbi(as);
 550}
 551
 552/*
 553 * Get an AFS superblock and root directory.
 554 */
 555static int afs_get_tree(struct fs_context *fc)
 556{
 557        struct afs_fs_context *ctx = fc->fs_private;
 558        struct super_block *sb;
 559        struct afs_super_info *as;
 560        int ret;
 561
 562        ret = afs_validate_fc(fc);
 563        if (ret)
 564                goto error;
 565
 566        _enter("");
 567
 568        /* allocate a superblock info record */
 569        ret = -ENOMEM;
 570        as = afs_alloc_sbi(fc);
 571        if (!as)
 572                goto error;
 573        fc->s_fs_info = as;
 574
 575        /* allocate a deviceless superblock */
 576        sb = sget_fc(fc,
 577                     as->dyn_root ? afs_dynroot_test_super : afs_test_super,
 578                     afs_set_super);
 579        if (IS_ERR(sb)) {
 580                ret = PTR_ERR(sb);
 581                goto error;
 582        }
 583
 584        if (!sb->s_root) {
 585                /* initial superblock/root creation */
 586                _debug("create");
 587                ret = afs_fill_super(sb, ctx);
 588                if (ret < 0)
 589                        goto error_sb;
 590                sb->s_flags |= SB_ACTIVE;
 591        } else {
 592                _debug("reuse");
 593                ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
 594        }
 595
 596        fc->root = dget(sb->s_root);
 597        trace_afs_get_tree(as->cell, as->volume);
 598        _leave(" = 0 [%p]", sb);
 599        return 0;
 600
 601error_sb:
 602        deactivate_locked_super(sb);
 603error:
 604        _leave(" = %d", ret);
 605        return ret;
 606}
 607
 608static void afs_free_fc(struct fs_context *fc)
 609{
 610        struct afs_fs_context *ctx = fc->fs_private;
 611
 612        afs_destroy_sbi(fc->s_fs_info);
 613        afs_put_volume(ctx->net, ctx->volume, afs_volume_trace_put_free_fc);
 614        afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
 615        key_put(ctx->key);
 616        kfree(ctx);
 617}
 618
 619static const struct fs_context_operations afs_context_ops = {
 620        .free           = afs_free_fc,
 621        .parse_param    = afs_parse_param,
 622        .get_tree       = afs_get_tree,
 623};
 624
 625/*
 626 * Set up the filesystem mount context.
 627 */
 628static int afs_init_fs_context(struct fs_context *fc)
 629{
 630        struct afs_fs_context *ctx;
 631        struct afs_cell *cell;
 632
 633        ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
 634        if (!ctx)
 635                return -ENOMEM;
 636
 637        ctx->type = AFSVL_ROVOL;
 638        ctx->net = afs_net(fc->net_ns);
 639
 640        /* Default to the workstation cell. */
 641        cell = afs_find_cell(ctx->net, NULL, 0, afs_cell_trace_use_fc);
 642        if (IS_ERR(cell))
 643                cell = NULL;
 644        ctx->cell = cell;
 645
 646        fc->fs_private = ctx;
 647        fc->ops = &afs_context_ops;
 648        return 0;
 649}
 650
 651/*
 652 * Initialise an inode cache slab element prior to any use.  Note that
 653 * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
 654 * inode to another.
 655 */
 656static void afs_i_init_once(void *_vnode)
 657{
 658        struct afs_vnode *vnode = _vnode;
 659
 660        memset(vnode, 0, sizeof(*vnode));
 661        inode_init_once(&vnode->vfs_inode);
 662        mutex_init(&vnode->io_lock);
 663        init_rwsem(&vnode->validate_lock);
 664        spin_lock_init(&vnode->wb_lock);
 665        spin_lock_init(&vnode->lock);
 666        INIT_LIST_HEAD(&vnode->wb_keys);
 667        INIT_LIST_HEAD(&vnode->pending_locks);
 668        INIT_LIST_HEAD(&vnode->granted_locks);
 669        INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 670        seqlock_init(&vnode->cb_lock);
 671}
 672
 673/*
 674 * allocate an AFS inode struct from our slab cache
 675 */
 676static struct inode *afs_alloc_inode(struct super_block *sb)
 677{
 678        struct afs_vnode *vnode;
 679
 680        vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 681        if (!vnode)
 682                return NULL;
 683
 684        atomic_inc(&afs_count_active_inodes);
 685
 686        /* Reset anything that shouldn't leak from one inode to the next. */
 687        memset(&vnode->fid, 0, sizeof(vnode->fid));
 688        memset(&vnode->status, 0, sizeof(vnode->status));
 689
 690        vnode->volume           = NULL;
 691        vnode->lock_key         = NULL;
 692        vnode->permit_cache     = NULL;
 693#ifdef CONFIG_AFS_FSCACHE
 694        vnode->cache            = NULL;
 695#endif
 696
 697        vnode->flags            = 1 << AFS_VNODE_UNSET;
 698        vnode->lock_state       = AFS_VNODE_LOCK_NONE;
 699
 700        init_rwsem(&vnode->rmdir_lock);
 701
 702        _leave(" = %p", &vnode->vfs_inode);
 703        return &vnode->vfs_inode;
 704}
 705
 706static void afs_free_inode(struct inode *inode)
 707{
 708        kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
 709}
 710
 711/*
 712 * destroy an AFS inode struct
 713 */
 714static void afs_destroy_inode(struct inode *inode)
 715{
 716        struct afs_vnode *vnode = AFS_FS_I(inode);
 717
 718        _enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
 719
 720        _debug("DESTROY INODE %p", inode);
 721
 722        atomic_dec(&afs_count_active_inodes);
 723}
 724
 725static void afs_get_volume_status_success(struct afs_operation *op)
 726{
 727        struct afs_volume_status *vs = &op->volstatus.vs;
 728        struct kstatfs *buf = op->volstatus.buf;
 729
 730        if (vs->max_quota == 0)
 731                buf->f_blocks = vs->part_max_blocks;
 732        else
 733                buf->f_blocks = vs->max_quota;
 734
 735        if (buf->f_blocks > vs->blocks_in_use)
 736                buf->f_bavail = buf->f_bfree =
 737                        buf->f_blocks - vs->blocks_in_use;
 738}
 739
 740static const struct afs_operation_ops afs_get_volume_status_operation = {
 741        .issue_afs_rpc  = afs_fs_get_volume_status,
 742        .issue_yfs_rpc  = yfs_fs_get_volume_status,
 743        .success        = afs_get_volume_status_success,
 744};
 745
 746/*
 747 * return information about an AFS volume
 748 */
 749static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 750{
 751        struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
 752        struct afs_operation *op;
 753        struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 754
 755        buf->f_type     = dentry->d_sb->s_magic;
 756        buf->f_bsize    = AFS_BLOCK_SIZE;
 757        buf->f_namelen  = AFSNAMEMAX - 1;
 758
 759        if (as->dyn_root) {
 760                buf->f_blocks   = 1;
 761                buf->f_bavail   = 0;
 762                buf->f_bfree    = 0;
 763                return 0;
 764        }
 765
 766        op = afs_alloc_operation(NULL, as->volume);
 767        if (IS_ERR(op))
 768                return PTR_ERR(op);
 769
 770        afs_op_set_vnode(op, 0, vnode);
 771        op->nr_files            = 1;
 772        op->volstatus.buf       = buf;
 773        op->ops                 = &afs_get_volume_status_operation;
 774        return afs_do_sync_operation(op);
 775}
 776