LXR linux/fs/affs/namei.c

   1/*
   2 *  linux/fs/affs/namei.c
   3 *
   4 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5 *
   6 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   7 *
   8 *  (C) 1991  Linus Torvalds - minix filesystem
   9 */
  10
  11#include "affs.h"
  12
  13typedef int (*toupper_t)(int);
  14
  15static int       affs_toupper(int ch);
  16static int       affs_hash_dentry(const struct dentry *, struct qstr *);
  17static int       affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
  18                unsigned int len, const char *str, const struct qstr *name);
  19static int       affs_intl_toupper(int ch);
  20static int       affs_intl_hash_dentry(const struct dentry *, struct qstr *);
  21static int       affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
  22                unsigned int len, const char *str, const struct qstr *name);
  23
  24const struct dentry_operations affs_dentry_operations = {
  25        .d_hash         = affs_hash_dentry,
  26        .d_compare      = affs_compare_dentry,
  27};
  28
  29const struct dentry_operations affs_intl_dentry_operations = {
  30        .d_hash         = affs_intl_hash_dentry,
  31        .d_compare      = affs_intl_compare_dentry,
  32};
  33
  34
  35/* Simple toupper() for DOS\1 */
  36
  37static int
  38affs_toupper(int ch)
  39{
  40        return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
  41}
  42
  43/* International toupper() for DOS\3 ("international") */
  44
  45static int
  46affs_intl_toupper(int ch)
  47{
  48        return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
  49                && ch <= 0xFE && ch != 0xF7) ?
  50                ch - ('a' - 'A') : ch;
  51}
  52
  53static inline toupper_t
  54affs_get_toupper(struct super_block *sb)
  55{
  56        return affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL) ?
  57               affs_intl_toupper : affs_toupper;
  58}
  59
  60/*
  61 * Note: the dentry argument is the parent dentry.
  62 */
  63static inline int
  64__affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
  65{
  66        const u8 *name = qstr->name;
  67        unsigned long hash;
  68        int retval;
  69        u32 len;
  70
  71        retval = affs_check_name(qstr->name, qstr->len, notruncate);
  72        if (retval)
  73                return retval;
  74
  75        hash = init_name_hash();
  76        len = min(qstr->len, AFFSNAMEMAX);
  77        for (; len > 0; name++, len--)
  78                hash = partial_name_hash(toupper(*name), hash);
  79        qstr->hash = end_name_hash(hash);
  80
  81        return 0;
  82}
  83
  84static int
  85affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
  86{
  87        return __affs_hash_dentry(qstr, affs_toupper,
  88                                  affs_nofilenametruncate(dentry));
  89
  90}
  91
  92static int
  93affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
  94{
  95        return __affs_hash_dentry(qstr, affs_intl_toupper,
  96                                  affs_nofilenametruncate(dentry));
  97
  98}
  99
 100static inline int __affs_compare_dentry(unsigned int len,
 101                const char *str, const struct qstr *name, toupper_t toupper,
 102                bool notruncate)
 103{
 104        const u8 *aname = str;
 105        const u8 *bname = name->name;
 106
 107        /*
 108         * 'str' is the name of an already existing dentry, so the name
 109         * must be valid. 'name' must be validated first.
 110         */
 111
 112        if (affs_check_name(name->name, name->len, notruncate))
 113                return 1;
 114
 115        /*
 116         * If the names are longer than the allowed 30 chars,
 117         * the excess is ignored, so their length may differ.
 118         */
 119        if (len >= AFFSNAMEMAX) {
 120                if (name->len < AFFSNAMEMAX)
 121                        return 1;
 122                len = AFFSNAMEMAX;
 123        } else if (len != name->len)
 124                return 1;
 125
 126        for (; len > 0; len--)
 127                if (toupper(*aname++) != toupper(*bname++))
 128                        return 1;
 129
 130        return 0;
 131}
 132
 133static int
 134affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
 135                unsigned int len, const char *str, const struct qstr *name)
 136{
 137
 138        return __affs_compare_dentry(len, str, name, affs_toupper,
 139                                     affs_nofilenametruncate(parent));
 140}
 141
 142static int
 143affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
 144                unsigned int len, const char *str, const struct qstr *name)
 145{
 146        return __affs_compare_dentry(len, str, name, affs_intl_toupper,
 147                                     affs_nofilenametruncate(parent));
 148
 149}
 150
 151/*
 152 * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
 153 */
 154
 155static inline int
 156affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
 157{
 158        const u8 *name = dentry->d_name.name;
 159        int len = dentry->d_name.len;
 160
 161        if (len >= AFFSNAMEMAX) {
 162                if (*name2 < AFFSNAMEMAX)
 163                        return 0;
 164                len = AFFSNAMEMAX;
 165        } else if (len != *name2)
 166                return 0;
 167
 168        for (name2++; len > 0; len--)
 169                if (toupper(*name++) != toupper(*name2++))
 170                        return 0;
 171        return 1;
 172}
 173
 174int
 175affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
 176{
 177        toupper_t toupper = affs_get_toupper(sb);
 178        u32 hash;
 179
 180        hash = len = min(len, AFFSNAMEMAX);
 181        for (; len > 0; len--)
 182                hash = (hash * 13 + toupper(*name++)) & 0x7ff;
 183
 184        return hash % AFFS_SB(sb)->s_hashsize;
 185}
 186
 187static struct buffer_head *
 188affs_find_entry(struct inode *dir, struct dentry *dentry)
 189{
 190        struct super_block *sb = dir->i_sb;
 191        struct buffer_head *bh;
 192        toupper_t toupper = affs_get_toupper(sb);
 193        u32 key;
 194
 195        pr_debug("%s(\"%pd\")\n", __func__, dentry);
 196
 197        bh = affs_bread(sb, dir->i_ino);
 198        if (!bh)
 199                return ERR_PTR(-EIO);
 200
 201        key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
 202
 203        for (;;) {
 204                affs_brelse(bh);
 205                if (key == 0)
 206                        return NULL;
 207                bh = affs_bread(sb, key);
 208                if (!bh)
 209                        return ERR_PTR(-EIO);
 210                if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
 211                        return bh;
 212                key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
 213        }
 214}
 215
 216struct dentry *
 217affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 218{
 219        struct super_block *sb = dir->i_sb;
 220        struct buffer_head *bh;
 221        struct inode *inode = NULL;
 222
 223        pr_debug("%s(\"%pd\")\n", __func__, dentry);
 224
 225        affs_lock_dir(dir);
 226        bh = affs_find_entry(dir, dentry);
 227        affs_unlock_dir(dir);
 228        if (IS_ERR(bh))
 229                return ERR_CAST(bh);
 230        if (bh) {
 231                u32 ino = bh->b_blocknr;
 232
 233                /* store the real header ino in d_fsdata for faster lookups */
 234                dentry->d_fsdata = (void *)(long)ino;
 235                switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
 236                //link to dirs disabled
 237                //case ST_LINKDIR:
 238                case ST_LINKFILE:
 239                        ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
 240                }
 241                affs_brelse(bh);
 242                inode = affs_iget(sb, ino);
 243                if (IS_ERR(inode))
 244                        return ERR_CAST(inode);
 245        }
 246        d_add(dentry, inode);
 247        return NULL;
 248}
 249
 250int
 251affs_unlink(struct inode *dir, struct dentry *dentry)
 252{
 253        pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
 254                 d_inode(dentry)->i_ino, dentry);
 255
 256        return affs_remove_header(dentry);
 257}
 258
 259int
 260affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 261{
 262        struct super_block *sb = dir->i_sb;
 263        struct inode    *inode;
 264        int              error;
 265
 266        pr_debug("%s(%lu,\"%pd\",0%ho)\n",
 267                 __func__, dir->i_ino, dentry, mode);
 268
 269        inode = affs_new_inode(dir);
 270        if (!inode)
 271                return -ENOSPC;
 272
 273        inode->i_mode = mode;
 274        mode_to_prot(inode);
 275        mark_inode_dirty(inode);
 276
 277        inode->i_op = &affs_file_inode_operations;
 278        inode->i_fop = &affs_file_operations;
 279        inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
 280                                  &affs_aops_ofs : &affs_aops;
 281        error = affs_add_entry(dir, inode, dentry, ST_FILE);
 282        if (error) {
 283                clear_nlink(inode);
 284                iput(inode);
 285                return error;
 286        }
 287        return 0;
 288}
 289
 290int
 291affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 292{
 293        struct inode            *inode;
 294        int                      error;
 295
 296        pr_debug("%s(%lu,\"%pd\",0%ho)\n",
 297                 __func__, dir->i_ino, dentry, mode);
 298
 299        inode = affs_new_inode(dir);
 300        if (!inode)
 301                return -ENOSPC;
 302
 303        inode->i_mode = S_IFDIR | mode;
 304        mode_to_prot(inode);
 305
 306        inode->i_op = &affs_dir_inode_operations;
 307        inode->i_fop = &affs_dir_operations;
 308
 309        error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
 310        if (error) {
 311                clear_nlink(inode);
 312                mark_inode_dirty(inode);
 313                iput(inode);
 314                return error;
 315        }
 316        return 0;
 317}
 318
 319int
 320affs_rmdir(struct inode *dir, struct dentry *dentry)
 321{
 322        pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
 323                 d_inode(dentry)->i_ino, dentry);
 324
 325        return affs_remove_header(dentry);
 326}
 327
 328int
 329affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 330{
 331        struct super_block      *sb = dir->i_sb;
 332        struct buffer_head      *bh;
 333        struct inode            *inode;
 334        char                    *p;
 335        int                      i, maxlen, error;
 336        char                     c, lc;
 337
 338        pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
 339                 __func__, dir->i_ino, dentry, symname);
 340
 341        maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
 342        inode  = affs_new_inode(dir);
 343        if (!inode)
 344                return -ENOSPC;
 345
 346        inode->i_op = &affs_symlink_inode_operations;
 347        inode_nohighmem(inode);
 348        inode->i_data.a_ops = &affs_symlink_aops;
 349        inode->i_mode = S_IFLNK | 0777;
 350        mode_to_prot(inode);
 351
 352        error = -EIO;
 353        bh = affs_bread(sb, inode->i_ino);
 354        if (!bh)
 355                goto err;
 356        i  = 0;
 357        p  = (char *)AFFS_HEAD(bh)->table;
 358        lc = '/';
 359        if (*symname == '/') {
 360                struct affs_sb_info *sbi = AFFS_SB(sb);
 361                while (*symname == '/')
 362                        symname++;
 363                spin_lock(&sbi->symlink_lock);
 364                while (sbi->s_volume[i])        /* Cannot overflow */
 365                        *p++ = sbi->s_volume[i++];
 366                spin_unlock(&sbi->symlink_lock);
 367        }
 368        while (i < maxlen && (c = *symname++)) {
 369                if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
 370                        *p++ = '/';
 371                        i++;
 372                        symname += 2;
 373                        lc = '/';
 374                } else if (c == '.' && lc == '/' && *symname == '/') {
 375                        symname++;
 376                        lc = '/';
 377                } else {
 378                        *p++ = c;
 379                        lc   = c;
 380                        i++;
 381                }
 382                if (lc == '/')
 383                        while (*symname == '/')
 384                                symname++;
 385        }
 386        *p = 0;
 387        mark_buffer_dirty_inode(bh, inode);
 388        affs_brelse(bh);
 389        mark_inode_dirty(inode);
 390
 391        error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
 392        if (error)
 393                goto err;
 394
 395        return 0;
 396
 397err:
 398        clear_nlink(inode);
 399        mark_inode_dirty(inode);
 400        iput(inode);
 401        return error;
 402}
 403
 404int
 405affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
 406{
 407        struct inode *inode = d_inode(old_dentry);
 408
 409        pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
 410                 dentry);
 411
 412        return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
 413}
 414
 415int
 416affs_rename(struct inode *old_dir, struct dentry *old_dentry,
 417            struct inode *new_dir, struct dentry *new_dentry)
 418{
 419        struct super_block *sb = old_dir->i_sb;
 420        struct buffer_head *bh = NULL;
 421        int retval;
 422
 423        pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
 424                 old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
 425
 426        retval = affs_check_name(new_dentry->d_name.name,
 427                                 new_dentry->d_name.len,
 428                                 affs_nofilenametruncate(old_dentry));
 429
 430        if (retval)
 431                return retval;
 432
 433        /* Unlink destination if it already exists */
 434        if (d_really_is_positive(new_dentry)) {
 435                retval = affs_remove_header(new_dentry);
 436                if (retval)
 437                        return retval;
 438        }
 439
 440        bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
 441        if (!bh)
 442                return -EIO;
 443
 444        /* Remove header from its parent directory. */
 445        affs_lock_dir(old_dir);
 446        retval = affs_remove_hash(old_dir, bh);
 447        affs_unlock_dir(old_dir);
 448        if (retval)
 449                goto done;
 450
 451        /* And insert it into the new directory with the new name. */
 452        affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
 453        affs_fix_checksum(sb, bh);
 454        affs_lock_dir(new_dir);
 455        retval = affs_insert_hash(new_dir, bh);
 456        affs_unlock_dir(new_dir);
 457        /* TODO: move it back to old_dir, if error? */
 458
 459done:
 460        mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
 461        affs_brelse(bh);
 462        return retval;
 463}
 464