linux/fs/befs/linuxvfs.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * linux/fs/befs/linuxvfs.c
   4 *
   5 * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
   6 *
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/module.h>
  12#include <linux/slab.h>
  13#include <linux/fs.h>
  14#include <linux/errno.h>
  15#include <linux/stat.h>
  16#include <linux/nls.h>
  17#include <linux/buffer_head.h>
  18#include <linux/vfs.h>
  19#include <linux/parser.h>
  20#include <linux/namei.h>
  21#include <linux/sched.h>
  22#include <linux/cred.h>
  23#include <linux/exportfs.h>
  24#include <linux/seq_file.h>
  25
  26#include "befs.h"
  27#include "btree.h"
  28#include "inode.h"
  29#include "datastream.h"
  30#include "super.h"
  31#include "io.h"
  32
  33MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
  34MODULE_AUTHOR("Will Dyson");
  35MODULE_LICENSE("GPL");
  36
  37/* The units the vfs expects inode->i_blocks to be in */
  38#define VFS_BLOCK_SIZE 512
  39
  40static int befs_readdir(struct file *, struct dir_context *);
  41static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
  42static int befs_readpage(struct file *file, struct page *page);
  43static sector_t befs_bmap(struct address_space *mapping, sector_t block);
  44static struct dentry *befs_lookup(struct inode *, struct dentry *,
  45                                  unsigned int);
  46static struct inode *befs_iget(struct super_block *, unsigned long);
  47static struct inode *befs_alloc_inode(struct super_block *sb);
  48static void befs_free_inode(struct inode *inode);
  49static void befs_destroy_inodecache(void);
  50static int befs_symlink_readpage(struct file *, struct page *);
  51static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
  52                        char **out, int *out_len);
  53static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
  54                        char **out, int *out_len);
  55static void befs_put_super(struct super_block *);
  56static int befs_remount(struct super_block *, int *, char *);
  57static int befs_statfs(struct dentry *, struct kstatfs *);
  58static int befs_show_options(struct seq_file *, struct dentry *);
  59static int parse_options(char *, struct befs_mount_options *);
  60static struct dentry *befs_fh_to_dentry(struct super_block *sb,
  61                                struct fid *fid, int fh_len, int fh_type);
  62static struct dentry *befs_fh_to_parent(struct super_block *sb,
  63                                struct fid *fid, int fh_len, int fh_type);
  64static struct dentry *befs_get_parent(struct dentry *child);
  65
  66static const struct super_operations befs_sops = {
  67        .alloc_inode    = befs_alloc_inode,     /* allocate a new inode */
  68        .free_inode     = befs_free_inode, /* deallocate an inode */
  69        .put_super      = befs_put_super,       /* uninit super */
  70        .statfs         = befs_statfs,  /* statfs */
  71        .remount_fs     = befs_remount,
  72        .show_options   = befs_show_options,
  73};
  74
  75/* slab cache for befs_inode_info objects */
  76static struct kmem_cache *befs_inode_cachep;
  77
  78static const struct file_operations befs_dir_operations = {
  79        .read           = generic_read_dir,
  80        .iterate_shared = befs_readdir,
  81        .llseek         = generic_file_llseek,
  82};
  83
  84static const struct inode_operations befs_dir_inode_operations = {
  85        .lookup         = befs_lookup,
  86};
  87
  88static const struct address_space_operations befs_aops = {
  89        .readpage       = befs_readpage,
  90        .bmap           = befs_bmap,
  91};
  92
  93static const struct address_space_operations befs_symlink_aops = {
  94        .readpage       = befs_symlink_readpage,
  95};
  96
  97static const struct export_operations befs_export_operations = {
  98        .fh_to_dentry   = befs_fh_to_dentry,
  99        .fh_to_parent   = befs_fh_to_parent,
 100        .get_parent     = befs_get_parent,
 101};
 102
 103/*
 104 * Called by generic_file_read() to read a page of data
 105 *
 106 * In turn, simply calls a generic block read function and
 107 * passes it the address of befs_get_block, for mapping file
 108 * positions to disk blocks.
 109 */
 110static int
 111befs_readpage(struct file *file, struct page *page)
 112{
 113        return block_read_full_page(page, befs_get_block);
 114}
 115
 116static sector_t
 117befs_bmap(struct address_space *mapping, sector_t block)
 118{
 119        return generic_block_bmap(mapping, block, befs_get_block);
 120}
 121
 122/*
 123 * Generic function to map a file position (block) to a
 124 * disk offset (passed back in bh_result).
 125 *
 126 * Used by many higher level functions.
 127 *
 128 * Calls befs_fblock2brun() in datastream.c to do the real work.
 129 */
 130
 131static int
 132befs_get_block(struct inode *inode, sector_t block,
 133               struct buffer_head *bh_result, int create)
 134{
 135        struct super_block *sb = inode->i_sb;
 136        befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
 137        befs_block_run run = BAD_IADDR;
 138        int res;
 139        ulong disk_off;
 140
 141        befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
 142                   (unsigned long)inode->i_ino, (long)block);
 143        if (create) {
 144                befs_error(sb, "befs_get_block() was asked to write to "
 145                           "block %ld in inode %lu", (long)block,
 146                           (unsigned long)inode->i_ino);
 147                return -EPERM;
 148        }
 149
 150        res = befs_fblock2brun(sb, ds, block, &run);
 151        if (res != BEFS_OK) {
 152                befs_error(sb,
 153                           "<--- %s for inode %lu, block %ld ERROR",
 154                           __func__, (unsigned long)inode->i_ino,
 155                           (long)block);
 156                return -EFBIG;
 157        }
 158
 159        disk_off = (ulong) iaddr2blockno(sb, &run);
 160
 161        map_bh(bh_result, inode->i_sb, disk_off);
 162
 163        befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
 164                  __func__, (unsigned long)inode->i_ino, (long)block,
 165                  (unsigned long)disk_off);
 166
 167        return 0;
 168}
 169
 170static struct dentry *
 171befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 172{
 173        struct inode *inode;
 174        struct super_block *sb = dir->i_sb;
 175        const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
 176        befs_off_t offset;
 177        int ret;
 178        int utfnamelen;
 179        char *utfname;
 180        const char *name = dentry->d_name.name;
 181
 182        befs_debug(sb, "---> %s name %pd inode %ld", __func__,
 183                   dentry, dir->i_ino);
 184
 185        /* Convert to UTF-8 */
 186        if (BEFS_SB(sb)->nls) {
 187                ret =
 188                    befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
 189                if (ret < 0) {
 190                        befs_debug(sb, "<--- %s ERROR", __func__);
 191                        return ERR_PTR(ret);
 192                }
 193                ret = befs_btree_find(sb, ds, utfname, &offset);
 194                kfree(utfname);
 195
 196        } else {
 197                ret = befs_btree_find(sb, ds, name, &offset);
 198        }
 199
 200        if (ret == BEFS_BT_NOT_FOUND) {
 201                befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
 202                inode = NULL;
 203        } else if (ret != BEFS_OK || offset == 0) {
 204                befs_error(sb, "<--- %s Error", __func__);
 205                inode = ERR_PTR(-ENODATA);
 206        } else {
 207                inode = befs_iget(dir->i_sb, (ino_t) offset);
 208        }
 209        befs_debug(sb, "<--- %s", __func__);
 210
 211        return d_splice_alias(inode, dentry);
 212}
 213
 214static int
 215befs_readdir(struct file *file, struct dir_context *ctx)
 216{
 217        struct inode *inode = file_inode(file);
 218        struct super_block *sb = inode->i_sb;
 219        const befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
 220        befs_off_t value;
 221        int result;
 222        size_t keysize;
 223        char keybuf[BEFS_NAME_LEN + 1];
 224
 225        befs_debug(sb, "---> %s name %pD, inode %ld, ctx->pos %lld",
 226                  __func__, file, inode->i_ino, ctx->pos);
 227
 228        while (1) {
 229                result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
 230                                         keybuf, &keysize, &value);
 231
 232                if (result == BEFS_ERR) {
 233                        befs_debug(sb, "<--- %s ERROR", __func__);
 234                        befs_error(sb, "IO error reading %pD (inode %lu)",
 235                                   file, inode->i_ino);
 236                        return -EIO;
 237
 238                } else if (result == BEFS_BT_END) {
 239                        befs_debug(sb, "<--- %s END", __func__);
 240                        return 0;
 241
 242                } else if (result == BEFS_BT_EMPTY) {
 243                        befs_debug(sb, "<--- %s Empty directory", __func__);
 244                        return 0;
 245                }
 246
 247                /* Convert to NLS */
 248                if (BEFS_SB(sb)->nls) {
 249                        char *nlsname;
 250                        int nlsnamelen;
 251
 252                        result =
 253                            befs_utf2nls(sb, keybuf, keysize, &nlsname,
 254                                         &nlsnamelen);
 255                        if (result < 0) {
 256                                befs_debug(sb, "<--- %s ERROR", __func__);
 257                                return result;
 258                        }
 259                        if (!dir_emit(ctx, nlsname, nlsnamelen,
 260                                      (ino_t) value, DT_UNKNOWN)) {
 261                                kfree(nlsname);
 262                                return 0;
 263                        }
 264                        kfree(nlsname);
 265                } else {
 266                        if (!dir_emit(ctx, keybuf, keysize,
 267                                      (ino_t) value, DT_UNKNOWN))
 268                                return 0;
 269                }
 270                ctx->pos++;
 271        }
 272}
 273
 274static struct inode *
 275befs_alloc_inode(struct super_block *sb)
 276{
 277        struct befs_inode_info *bi;
 278
 279        bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL);
 280        if (!bi)
 281                return NULL;
 282        return &bi->vfs_inode;
 283}
 284
 285static void befs_free_inode(struct inode *inode)
 286{
 287        kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
 288}
 289
 290static void init_once(void *foo)
 291{
 292        struct befs_inode_info *bi = (struct befs_inode_info *) foo;
 293
 294        inode_init_once(&bi->vfs_inode);
 295}
 296
 297static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 298{
 299        struct buffer_head *bh;
 300        befs_inode *raw_inode;
 301        struct befs_sb_info *befs_sb = BEFS_SB(sb);
 302        struct befs_inode_info *befs_ino;
 303        struct inode *inode;
 304
 305        befs_debug(sb, "---> %s inode = %lu", __func__, ino);
 306
 307        inode = iget_locked(sb, ino);
 308        if (!inode)
 309                return ERR_PTR(-ENOMEM);
 310        if (!(inode->i_state & I_NEW))
 311                return inode;
 312
 313        befs_ino = BEFS_I(inode);
 314
 315        /* convert from vfs's inode number to befs's inode number */
 316        befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);
 317
 318        befs_debug(sb, "  real inode number [%u, %hu, %hu]",
 319                   befs_ino->i_inode_num.allocation_group,
 320                   befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
 321
 322        bh = sb_bread(sb, inode->i_ino);
 323        if (!bh) {
 324                befs_error(sb, "unable to read inode block - "
 325                           "inode = %lu", inode->i_ino);
 326                goto unacquire_none;
 327        }
 328
 329        raw_inode = (befs_inode *) bh->b_data;
 330
 331        befs_dump_inode(sb, raw_inode);
 332
 333        if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
 334                befs_error(sb, "Bad inode: %lu", inode->i_ino);
 335                goto unacquire_bh;
 336        }
 337
 338        inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);
 339
 340        /*
 341         * set uid and gid.  But since current BeOS is single user OS, so
 342         * you can change by "uid" or "gid" options.
 343         */
 344
 345        inode->i_uid = befs_sb->mount_opts.use_uid ?
 346                befs_sb->mount_opts.uid :
 347                make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
 348        inode->i_gid = befs_sb->mount_opts.use_gid ?
 349                befs_sb->mount_opts.gid :
 350                make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));
 351
 352        set_nlink(inode, 1);
 353
 354        /*
 355         * BEFS's time is 64 bits, but current VFS is 32 bits...
 356         * BEFS don't have access time. Nor inode change time. VFS
 357         * doesn't have creation time.
 358         * Also, the lower 16 bits of the last_modified_time and
 359         * create_time are just a counter to help ensure uniqueness
 360         * for indexing purposes. (PFD, page 54)
 361         */
 362
 363        inode->i_mtime.tv_sec =
 364            fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16;
 365        inode->i_mtime.tv_nsec = 0;   /* lower 16 bits are not a time */
 366        inode->i_ctime = inode->i_mtime;
 367        inode->i_atime = inode->i_mtime;
 368
 369        befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
 370        befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
 371        befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
 372        befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);
 373
 374        if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
 375                inode->i_size = 0;
 376                inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
 377                strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
 378                        BEFS_SYMLINK_LEN);
 379        } else {
 380                int num_blks;
 381
 382                befs_ino->i_data.ds =
 383                    fsds_to_cpu(sb, &raw_inode->data.datastream);
 384
 385                num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
 386                inode->i_blocks =
 387                    num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
 388                inode->i_size = befs_ino->i_data.ds.size;
 389        }
 390
 391        inode->i_mapping->a_ops = &befs_aops;
 392
 393        if (S_ISREG(inode->i_mode)) {
 394                inode->i_fop = &generic_ro_fops;
 395        } else if (S_ISDIR(inode->i_mode)) {
 396                inode->i_op = &befs_dir_inode_operations;
 397                inode->i_fop = &befs_dir_operations;
 398        } else if (S_ISLNK(inode->i_mode)) {
 399                if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
 400                        inode->i_op = &page_symlink_inode_operations;
 401                        inode_nohighmem(inode);
 402                        inode->i_mapping->a_ops = &befs_symlink_aops;
 403                } else {
 404                        inode->i_link = befs_ino->i_data.symlink;
 405                        inode->i_op = &simple_symlink_inode_operations;
 406                }
 407        } else {
 408                befs_error(sb, "Inode %lu is not a regular file, "
 409                           "directory or symlink. THAT IS WRONG! BeFS has no "
 410                           "on disk special files", inode->i_ino);
 411                goto unacquire_bh;
 412        }
 413
 414        brelse(bh);
 415        befs_debug(sb, "<--- %s", __func__);
 416        unlock_new_inode(inode);
 417        return inode;
 418
 419unacquire_bh:
 420        brelse(bh);
 421
 422unacquire_none:
 423        iget_failed(inode);
 424        befs_debug(sb, "<--- %s - Bad inode", __func__);
 425        return ERR_PTR(-EIO);
 426}
 427
 428/* Initialize the inode cache. Called at fs setup.
 429 *
 430 * Taken from NFS implementation by Al Viro.
 431 */
 432static int __init
 433befs_init_inodecache(void)
 434{
 435        befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache",
 436                                sizeof(struct befs_inode_info), 0,
 437                                (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
 438                                        SLAB_ACCOUNT),
 439                                offsetof(struct befs_inode_info,
 440                                        i_data.symlink),
 441                                sizeof_field(struct befs_inode_info,
 442                                        i_data.symlink),
 443                                init_once);
 444        if (befs_inode_cachep == NULL)
 445                return -ENOMEM;
 446
 447        return 0;
 448}
 449
 450/* Called at fs teardown.
 451 *
 452 * Taken from NFS implementation by Al Viro.
 453 */
 454static void
 455befs_destroy_inodecache(void)
 456{
 457        /*
 458         * Make sure all delayed rcu free inodes are flushed before we
 459         * destroy cache.
 460         */
 461        rcu_barrier();
 462        kmem_cache_destroy(befs_inode_cachep);
 463}
 464
 465/*
 466 * The inode of symbolic link is different to data stream.
 467 * The data stream become link name. Unless the LONG_SYMLINK
 468 * flag is set.
 469 */
 470static int befs_symlink_readpage(struct file *unused, struct page *page)
 471{
 472        struct inode *inode = page->mapping->host;
 473        struct super_block *sb = inode->i_sb;
 474        struct befs_inode_info *befs_ino = BEFS_I(inode);
 475        befs_data_stream *data = &befs_ino->i_data.ds;
 476        befs_off_t len = data->size;
 477        char *link = page_address(page);
 478
 479        if (len == 0 || len > PAGE_SIZE) {
 480                befs_error(sb, "Long symlink with illegal length");
 481                goto fail;
 482        }
 483        befs_debug(sb, "Follow long symlink");
 484
 485        if (befs_read_lsymlink(sb, data, link, len) != len) {
 486                befs_error(sb, "Failed to read entire long symlink");
 487                goto fail;
 488        }
 489        link[len - 1] = '\0';
 490        SetPageUptodate(page);
 491        unlock_page(page);
 492        return 0;
 493fail:
 494        SetPageError(page);
 495        unlock_page(page);
 496        return -EIO;
 497}
 498
 499/*
 500 * UTF-8 to NLS charset convert routine
 501 *
 502 * Uses uni2char() / char2uni() rather than the nls tables directly
 503 */
 504static int
 505befs_utf2nls(struct super_block *sb, const char *in,
 506             int in_len, char **out, int *out_len)
 507{
 508        struct nls_table *nls = BEFS_SB(sb)->nls;
 509        int i, o;
 510        unicode_t uni;
 511        int unilen, utflen;
 512        char *result;
 513        /* The utf8->nls conversion won't make the final nls string bigger
 514         * than the utf one, but if the string is pure ascii they'll have the
 515         * same width and an extra char is needed to save the additional \0
 516         */
 517        int maxlen = in_len + 1;
 518
 519        befs_debug(sb, "---> %s", __func__);
 520
 521        if (!nls) {
 522                befs_error(sb, "%s called with no NLS table loaded", __func__);
 523                return -EINVAL;
 524        }
 525
 526        *out = result = kmalloc(maxlen, GFP_NOFS);
 527        if (!*out)
 528                return -ENOMEM;
 529
 530        for (i = o = 0; i < in_len; i += utflen, o += unilen) {
 531
 532                /* convert from UTF-8 to Unicode */
 533                utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
 534                if (utflen < 0)
 535                        goto conv_err;
 536
 537                /* convert from Unicode to nls */
 538                if (uni > MAX_WCHAR_T)
 539                        goto conv_err;
 540                unilen = nls->uni2char(uni, &result[o], in_len - o);
 541                if (unilen < 0)
 542                        goto conv_err;
 543        }
 544        result[o] = '\0';
 545        *out_len = o;
 546
 547        befs_debug(sb, "<--- %s", __func__);
 548
 549        return o;
 550
 551conv_err:
 552        befs_error(sb, "Name using character set %s contains a character that "
 553                   "cannot be converted to unicode.", nls->charset);
 554        befs_debug(sb, "<--- %s", __func__);
 555        kfree(result);
 556        return -EILSEQ;
 557}
 558
 559/**
 560 * befs_nls2utf - Convert NLS string to utf8 encodeing
 561 * @sb: Superblock
 562 * @in: Input string buffer in NLS format
 563 * @in_len: Length of input string in bytes
 564 * @out: The output string in UTF-8 format
 565 * @out_len: Length of the output buffer
 566 *
 567 * Converts input string @in, which is in the format of the loaded NLS map,
 568 * into a utf8 string.
 569 *
 570 * The destination string @out is allocated by this function and the caller is
 571 * responsible for freeing it with kfree()
 572 *
 573 * On return, *@out_len is the length of @out in bytes.
 574 *
 575 * On success, the return value is the number of utf8 characters written to
 576 * the output buffer @out.
 577 *
 578 * On Failure, a negative number coresponding to the error code is returned.
 579 */
 580
 581static int
 582befs_nls2utf(struct super_block *sb, const char *in,
 583             int in_len, char **out, int *out_len)
 584{
 585        struct nls_table *nls = BEFS_SB(sb)->nls;
 586        int i, o;
 587        wchar_t uni;
 588        int unilen, utflen;
 589        char *result;
 590        /*
 591         * There are nls characters that will translate to 3-chars-wide UTF-8
 592         * characters, an additional byte is needed to save the final \0
 593         * in special cases
 594         */
 595        int maxlen = (3 * in_len) + 1;
 596
 597        befs_debug(sb, "---> %s\n", __func__);
 598
 599        if (!nls) {
 600                befs_error(sb, "%s called with no NLS table loaded.",
 601                           __func__);
 602                return -EINVAL;
 603        }
 604
 605        *out = result = kmalloc(maxlen, GFP_NOFS);
 606        if (!*out) {
 607                *out_len = 0;
 608                return -ENOMEM;
 609        }
 610
 611        for (i = o = 0; i < in_len; i += unilen, o += utflen) {
 612
 613                /* convert from nls to unicode */
 614                unilen = nls->char2uni(&in[i], in_len - i, &uni);
 615                if (unilen < 0)
 616                        goto conv_err;
 617
 618                /* convert from unicode to UTF-8 */
 619                utflen = utf32_to_utf8(uni, &result[o], 3);
 620                if (utflen <= 0)
 621                        goto conv_err;
 622        }
 623
 624        result[o] = '\0';
 625        *out_len = o;
 626
 627        befs_debug(sb, "<--- %s", __func__);
 628
 629        return i;
 630
 631conv_err:
 632        befs_error(sb, "Name using character set %s contains a character that "
 633                   "cannot be converted to unicode.", nls->charset);
 634        befs_debug(sb, "<--- %s", __func__);
 635        kfree(result);
 636        return -EILSEQ;
 637}
 638
 639static struct inode *befs_nfs_get_inode(struct super_block *sb, uint64_t ino,
 640                                         uint32_t generation)
 641{
 642        /* No need to handle i_generation */
 643        return befs_iget(sb, ino);
 644}
 645
 646/*
 647 * Map a NFS file handle to a corresponding dentry
 648 */
 649static struct dentry *befs_fh_to_dentry(struct super_block *sb,
 650                                struct fid *fid, int fh_len, int fh_type)
 651{
 652        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 653                                    befs_nfs_get_inode);
 654}
 655
 656/*
 657 * Find the parent for a file specified by NFS handle
 658 */
 659static struct dentry *befs_fh_to_parent(struct super_block *sb,
 660                                struct fid *fid, int fh_len, int fh_type)
 661{
 662        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 663                                    befs_nfs_get_inode);
 664}
 665
 666static struct dentry *befs_get_parent(struct dentry *child)
 667{
 668        struct inode *parent;
 669        struct befs_inode_info *befs_ino = BEFS_I(d_inode(child));
 670
 671        parent = befs_iget(child->d_sb,
 672                           (unsigned long)befs_ino->i_parent.start);
 673        if (IS_ERR(parent))
 674                return ERR_CAST(parent);
 675
 676        return d_obtain_alias(parent);
 677}
 678
 679enum {
 680        Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
 681};
 682
 683static const match_table_t befs_tokens = {
 684        {Opt_uid, "uid=%d"},
 685        {Opt_gid, "gid=%d"},
 686        {Opt_charset, "iocharset=%s"},
 687        {Opt_debug, "debug"},
 688        {Opt_err, NULL}
 689};
 690
 691static int
 692parse_options(char *options, struct befs_mount_options *opts)
 693{
 694        char *p;
 695        substring_t args[MAX_OPT_ARGS];
 696        int option;
 697        kuid_t uid;
 698        kgid_t gid;
 699
 700        /* Initialize options */
 701        opts->uid = GLOBAL_ROOT_UID;
 702        opts->gid = GLOBAL_ROOT_GID;
 703        opts->use_uid = 0;
 704        opts->use_gid = 0;
 705        opts->iocharset = NULL;
 706        opts->debug = 0;
 707
 708        if (!options)
 709                return 1;
 710
 711        while ((p = strsep(&options, ",")) != NULL) {
 712                int token;
 713
 714                if (!*p)
 715                        continue;
 716
 717                token = match_token(p, befs_tokens, args);
 718                switch (token) {
 719                case Opt_uid:
 720                        if (match_int(&args[0], &option))
 721                                return 0;
 722                        uid = INVALID_UID;
 723                        if (option >= 0)
 724                                uid = make_kuid(current_user_ns(), option);
 725                        if (!uid_valid(uid)) {
 726                                pr_err("Invalid uid %d, "
 727                                       "using default\n", option);
 728                                break;
 729                        }
 730                        opts->uid = uid;
 731                        opts->use_uid = 1;
 732                        break;
 733                case Opt_gid:
 734                        if (match_int(&args[0], &option))
 735                                return 0;
 736                        gid = INVALID_GID;
 737                        if (option >= 0)
 738                                gid = make_kgid(current_user_ns(), option);
 739                        if (!gid_valid(gid)) {
 740                                pr_err("Invalid gid %d, "
 741                                       "using default\n", option);
 742                                break;
 743                        }
 744                        opts->gid = gid;
 745                        opts->use_gid = 1;
 746                        break;
 747                case Opt_charset:
 748                        kfree(opts->iocharset);
 749                        opts->iocharset = match_strdup(&args[0]);
 750                        if (!opts->iocharset) {
 751                                pr_err("allocation failure for "
 752                                       "iocharset string\n");
 753                                return 0;
 754                        }
 755                        break;
 756                case Opt_debug:
 757                        opts->debug = 1;
 758                        break;
 759                default:
 760                        pr_err("Unrecognized mount option \"%s\" "
 761                               "or missing value\n", p);
 762                        return 0;
 763                }
 764        }
 765        return 1;
 766}
 767
 768static int befs_show_options(struct seq_file *m, struct dentry *root)
 769{
 770        struct befs_sb_info *befs_sb = BEFS_SB(root->d_sb);
 771        struct befs_mount_options *opts = &befs_sb->mount_opts;
 772
 773        if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
 774                seq_printf(m, ",uid=%u",
 775                           from_kuid_munged(&init_user_ns, opts->uid));
 776        if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
 777                seq_printf(m, ",gid=%u",
 778                           from_kgid_munged(&init_user_ns, opts->gid));
 779        if (opts->iocharset)
 780                seq_printf(m, ",charset=%s", opts->iocharset);
 781        if (opts->debug)
 782                seq_puts(m, ",debug");
 783        return 0;
 784}
 785
 786/* This function has the responsibiltiy of getting the
 787 * filesystem ready for unmounting.
 788 * Basically, we free everything that we allocated in
 789 * befs_read_inode
 790 */
 791static void
 792befs_put_super(struct super_block *sb)
 793{
 794        kfree(BEFS_SB(sb)->mount_opts.iocharset);
 795        BEFS_SB(sb)->mount_opts.iocharset = NULL;
 796        unload_nls(BEFS_SB(sb)->nls);
 797        kfree(sb->s_fs_info);
 798        sb->s_fs_info = NULL;
 799}
 800
 801/* Allocate private field of the superblock, fill it.
 802 *
 803 * Finish filling the public superblock fields
 804 * Make the root directory
 805 * Load a set of NLS translations if needed.
 806 */
 807static int
 808befs_fill_super(struct super_block *sb, void *data, int silent)
 809{
 810        struct buffer_head *bh;
 811        struct befs_sb_info *befs_sb;
 812        befs_super_block *disk_sb;
 813        struct inode *root;
 814        long ret = -EINVAL;
 815        const unsigned long sb_block = 0;
 816        const off_t x86_sb_off = 512;
 817        int blocksize;
 818
 819        sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
 820        if (sb->s_fs_info == NULL)
 821                goto unacquire_none;
 822
 823        befs_sb = BEFS_SB(sb);
 824
 825        if (!parse_options((char *) data, &befs_sb->mount_opts)) {
 826                if (!silent)
 827                        befs_error(sb, "cannot parse mount options");
 828                goto unacquire_priv_sbp;
 829        }
 830
 831        befs_debug(sb, "---> %s", __func__);
 832
 833        if (!sb_rdonly(sb)) {
 834                befs_warning(sb,
 835                             "No write support. Marking filesystem read-only");
 836                sb->s_flags |= SB_RDONLY;
 837        }
 838
 839        /*
 840         * Set dummy blocksize to read super block.
 841         * Will be set to real fs blocksize later.
 842         *
 843         * Linux 2.4.10 and later refuse to read blocks smaller than
 844         * the logical block size for the device. But we also need to read at
 845         * least 1k to get the second 512 bytes of the volume.
 846         */
 847        blocksize = sb_min_blocksize(sb, 1024);
 848        if (!blocksize) {
 849                if (!silent)
 850                        befs_error(sb, "unable to set blocksize");
 851                goto unacquire_priv_sbp;
 852        }
 853
 854        bh = sb_bread(sb, sb_block);
 855        if (!bh) {
 856                if (!silent)
 857                        befs_error(sb, "unable to read superblock");
 858                goto unacquire_priv_sbp;
 859        }
 860
 861        /* account for offset of super block on x86 */
 862        disk_sb = (befs_super_block *) bh->b_data;
 863        if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
 864            (disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
 865                befs_debug(sb, "Using PPC superblock location");
 866        } else {
 867                befs_debug(sb, "Using x86 superblock location");
 868                disk_sb =
 869                    (befs_super_block *) ((void *) bh->b_data + x86_sb_off);
 870        }
 871
 872        if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
 873            (befs_check_sb(sb) != BEFS_OK))
 874                goto unacquire_bh;
 875
 876        befs_dump_super_block(sb, disk_sb);
 877
 878        brelse(bh);
 879
 880        if (befs_sb->num_blocks > ~((sector_t)0)) {
 881                if (!silent)
 882                        befs_error(sb, "blocks count: %llu is larger than the host can use",
 883                                        befs_sb->num_blocks);
 884                goto unacquire_priv_sbp;
 885        }
 886
 887        /*
 888         * set up enough so that it can read an inode
 889         * Fill in kernel superblock fields from private sb
 890         */
 891        sb->s_magic = BEFS_SUPER_MAGIC;
 892        /* Set real blocksize of fs */
 893        sb_set_blocksize(sb, (ulong) befs_sb->block_size);
 894        sb->s_op = &befs_sops;
 895        sb->s_export_op = &befs_export_operations;
 896        sb->s_time_min = 0;
 897        sb->s_time_max = 0xffffffffffffll;
 898        root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
 899        if (IS_ERR(root)) {
 900                ret = PTR_ERR(root);
 901                goto unacquire_priv_sbp;
 902        }
 903        sb->s_root = d_make_root(root);
 904        if (!sb->s_root) {
 905                if (!silent)
 906                        befs_error(sb, "get root inode failed");
 907                goto unacquire_priv_sbp;
 908        }
 909
 910        /* load nls library */
 911        if (befs_sb->mount_opts.iocharset) {
 912                befs_debug(sb, "Loading nls: %s",
 913                           befs_sb->mount_opts.iocharset);
 914                befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
 915                if (!befs_sb->nls) {
 916                        befs_warning(sb, "Cannot load nls %s"
 917                                        " loading default nls",
 918                                        befs_sb->mount_opts.iocharset);
 919                        befs_sb->nls = load_nls_default();
 920                }
 921        /* load default nls if none is specified  in mount options */
 922        } else {
 923                befs_debug(sb, "Loading default nls");
 924                befs_sb->nls = load_nls_default();
 925        }
 926
 927        return 0;
 928
 929unacquire_bh:
 930        brelse(bh);
 931
 932unacquire_priv_sbp:
 933        kfree(befs_sb->mount_opts.iocharset);
 934        kfree(sb->s_fs_info);
 935        sb->s_fs_info = NULL;
 936
 937unacquire_none:
 938        return ret;
 939}
 940
 941static int
 942befs_remount(struct super_block *sb, int *flags, char *data)
 943{
 944        sync_filesystem(sb);
 945        if (!(*flags & SB_RDONLY))
 946                return -EINVAL;
 947        return 0;
 948}
 949
 950static int
 951befs_statfs(struct dentry *dentry, struct kstatfs *buf)
 952{
 953        struct super_block *sb = dentry->d_sb;
 954        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 955
 956        befs_debug(sb, "---> %s", __func__);
 957
 958        buf->f_type = BEFS_SUPER_MAGIC;
 959        buf->f_bsize = sb->s_blocksize;
 960        buf->f_blocks = BEFS_SB(sb)->num_blocks;
 961        buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
 962        buf->f_bavail = buf->f_bfree;
 963        buf->f_files = 0;       /* UNKNOWN */
 964        buf->f_ffree = 0;       /* UNKNOWN */
 965        buf->f_fsid.val[0] = (u32)id;
 966        buf->f_fsid.val[1] = (u32)(id >> 32);
 967        buf->f_namelen = BEFS_NAME_LEN;
 968
 969        befs_debug(sb, "<--- %s", __func__);
 970
 971        return 0;
 972}
 973
 974static struct dentry *
 975befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
 976            void *data)
 977{
 978        return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
 979}
 980
 981static struct file_system_type befs_fs_type = {
 982        .owner          = THIS_MODULE,
 983        .name           = "befs",
 984        .mount          = befs_mount,
 985        .kill_sb        = kill_block_super,
 986        .fs_flags       = FS_REQUIRES_DEV,
 987};
 988MODULE_ALIAS_FS("befs");
 989
 990static int __init
 991init_befs_fs(void)
 992{
 993        int err;
 994
 995        pr_info("version: %s\n", BEFS_VERSION);
 996
 997        err = befs_init_inodecache();
 998        if (err)
 999                goto unacquire_none;
1000
1001        err = register_filesystem(&befs_fs_type);
1002        if (err)
1003                goto unacquire_inodecache;
1004
1005        return 0;
1006
1007unacquire_inodecache:
1008        befs_destroy_inodecache();
1009
1010unacquire_none:
1011        return err;
1012}
1013
1014static void __exit
1015exit_befs_fs(void)
1016{
1017        befs_destroy_inodecache();
1018
1019        unregister_filesystem(&befs_fs_type);
1020}
1021
1022/*
1023 * Macros that typecheck the init and exit functions,
1024 * ensures that they are called at init and cleanup,
1025 * and eliminates warnings about unused functions.
1026 */
1027module_init(init_befs_fs)
1028module_exit(exit_befs_fs)
1029