fs/befs/linuxvfs.c

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This source file includes following definitions.
befs_readpage
befs_bmap
befs_get_block
befs_lookup
befs_readdir
befs_alloc_inode
befs_free_inode
init_once
befs_iget
befs_init_inodecache
befs_destroy_inodecache
befs_symlink_readpage
befs_utf2nls
befs_nls2utf
befs_nfs_get_inode
befs_fh_to_dentry
befs_fh_to_parent
befs_get_parent
parse_options
befs_show_options
befs_put_super
befs_fill_super
befs_remount
befs_statfs
befs_mount
init_befs_fs
exit_befs_fs
   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 
  33 MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
  34 MODULE_AUTHOR("Will Dyson");
  35 MODULE_LICENSE("GPL");
  36 
  37 /* The units the vfs expects inode->i_blocks to be in */
  38 #define VFS_BLOCK_SIZE 512
  39 
  40 static int befs_readdir(struct file *, struct dir_context *);
  41 static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
  42 static int befs_readpage(struct file *file, struct page *page);
  43 static sector_t befs_bmap(struct address_space *mapping, sector_t block);
  44 static struct dentry *befs_lookup(struct inode *, struct dentry *,
  45                                   unsigned int);
  46 static struct inode *befs_iget(struct super_block *, unsigned long);
  47 static struct inode *befs_alloc_inode(struct super_block *sb);
  48 static void befs_free_inode(struct inode *inode);
  49 static void befs_destroy_inodecache(void);
  50 static int befs_symlink_readpage(struct file *, struct page *);
  51 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
  52                         char **out, int *out_len);
  53 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
  54                         char **out, int *out_len);
  55 static void befs_put_super(struct super_block *);
  56 static int befs_remount(struct super_block *, int *, char *);
  57 static int befs_statfs(struct dentry *, struct kstatfs *);
  58 static int befs_show_options(struct seq_file *, struct dentry *);
  59 static int parse_options(char *, struct befs_mount_options *);
  60 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
  61                                 struct fid *fid, int fh_len, int fh_type);
  62 static struct dentry *befs_fh_to_parent(struct super_block *sb,
  63                                 struct fid *fid, int fh_len, int fh_type);
  64 static struct dentry *befs_get_parent(struct dentry *child);
  65 
  66 static 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 */
  76 static struct kmem_cache *befs_inode_cachep;
  77 
  78 static const struct file_operations befs_dir_operations = {
  79         .read           = generic_read_dir,
  80         .iterate_shared = befs_readdir,
  81         .llseek         = generic_file_llseek,
  82 };
  83 
  84 static const struct inode_operations befs_dir_inode_operations = {
  85         .lookup         = befs_lookup,
  86 };
  87 
  88 static const struct address_space_operations befs_aops = {
  89         .readpage       = befs_readpage,
  90         .bmap           = befs_bmap,
  91 };
  92 
  93 static const struct address_space_operations befs_symlink_aops = {
  94         .readpage       = befs_symlink_readpage,
  95 };
  96 
  97 static 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  */
 110 static int
 111 befs_readpage(struct file *file, struct page *page)
 112 {
 113         return block_read_full_page(page, befs_get_block);
 114 }
 115 
 116 static sector_t
 117 befs_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 
 131 static int
 132 befs_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 
 170 static struct dentry *
 171 befs_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 
 214 static int
 215 befs_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 
 274 static struct inode *
 275 befs_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 
 285 static void befs_free_inode(struct inode *inode)
 286 {
 287         kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
 288 }
 289 
 290 static 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 
 297 static 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 
 419 unacquire_bh:
 420         brelse(bh);
 421 
 422 unacquire_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  */
 432 static int __init
 433 befs_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  */
 454 static void
 455 befs_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  */
 470 static 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;
 493 fail:
 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  */
 504 static int
 505 befs_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 
 551 conv_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 
 581 static int
 582 befs_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 
 631 conv_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 
 639 static 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  */
 649 static 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  */
 659 static 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 
 666 static 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 
 679 enum {
 680         Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
 681 };
 682 
 683 static 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 
 691 static int
 692 parse_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 
 768 static 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  */
 791 static void
 792 befs_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  */
 807 static int
 808 befs_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 
 929 unacquire_bh:
 930         brelse(bh);
 931 
 932 unacquire_priv_sbp:
 933         kfree(befs_sb->mount_opts.iocharset);
 934         kfree(sb->s_fs_info);
 935         sb->s_fs_info = NULL;
 936 
 937 unacquire_none:
 938         return ret;
 939 }
 940 
 941 static int
 942 befs_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 
 950 static int
 951 befs_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 
 974 static struct dentry *
 975 befs_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 
 981 static 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 };
 988 MODULE_ALIAS_FS("befs");
 989 
 990 static int __init
 991 init_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 
1007 unacquire_inodecache:
1008         befs_destroy_inodecache();
1009 
1010 unacquire_none:
1011         return err;
1012 }
1013 
1014 static void __exit
1015 exit_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  */
1027 module_init(init_befs_fs)
1028 module_exit(exit_befs_fs)
/* [<][>][^][v][top][bottom][index][help] */
root/fs/befs/linuxvfs.c

DEFINITIONS
