linux/fs/bfs/dir.c
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   1/*
   2 *      fs/bfs/dir.c
   3 *      BFS directory operations.
   4 *      Copyright (C) 1999,2000  Tigran Aivazian <tigran@veritas.com>
   5 *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
   6 */
   7
   8#include <linux/time.h>
   9#include <linux/string.h>
  10#include <linux/fs.h>
  11#include <linux/buffer_head.h>
  12#include <linux/sched.h>
  13#include "bfs.h"
  14
  15#undef DEBUG
  16
  17#ifdef DEBUG
  18#define dprintf(x...)   printf(x)
  19#else
  20#define dprintf(x...)
  21#endif
  22
  23static int bfs_add_entry(struct inode *dir, const unsigned char *name,
  24                                                int namelen, int ino);
  25static struct buffer_head *bfs_find_entry(struct inode *dir,
  26                                const unsigned char *name, int namelen,
  27                                struct bfs_dirent **res_dir);
  28
  29static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
  30{
  31        struct inode *dir = f->f_path.dentry->d_inode;
  32        struct buffer_head *bh;
  33        struct bfs_dirent *de;
  34        struct bfs_sb_info *info = BFS_SB(dir->i_sb);
  35        unsigned int offset;
  36        int block;
  37
  38        mutex_lock(&info->bfs_lock);
  39
  40        if (f->f_pos & (BFS_DIRENT_SIZE - 1)) {
  41                printf("Bad f_pos=%08lx for %s:%08lx\n",
  42                                        (unsigned long)f->f_pos,
  43                                        dir->i_sb->s_id, dir->i_ino);
  44                mutex_unlock(&info->bfs_lock);
  45                return -EBADF;
  46        }
  47
  48        while (f->f_pos < dir->i_size) {
  49                offset = f->f_pos & (BFS_BSIZE - 1);
  50                block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
  51                bh = sb_bread(dir->i_sb, block);
  52                if (!bh) {
  53                        f->f_pos += BFS_BSIZE - offset;
  54                        continue;
  55                }
  56                do {
  57                        de = (struct bfs_dirent *)(bh->b_data + offset);
  58                        if (de->ino) {
  59                                int size = strnlen(de->name, BFS_NAMELEN);
  60                                if (filldir(dirent, de->name, size, f->f_pos,
  61                                                le16_to_cpu(de->ino),
  62                                                DT_UNKNOWN) < 0) {
  63                                        brelse(bh);
  64                                        mutex_unlock(&info->bfs_lock);
  65                                        return 0;
  66                                }
  67                        }
  68                        offset += BFS_DIRENT_SIZE;
  69                        f->f_pos += BFS_DIRENT_SIZE;
  70                } while ((offset < BFS_BSIZE) && (f->f_pos < dir->i_size));
  71                brelse(bh);
  72        }
  73
  74        mutex_unlock(&info->bfs_lock);
  75        return 0;       
  76}
  77
  78const struct file_operations bfs_dir_operations = {
  79        .read           = generic_read_dir,
  80        .readdir        = bfs_readdir,
  81        .fsync          = generic_file_fsync,
  82        .llseek         = generic_file_llseek,
  83};
  84
  85extern void dump_imap(const char *, struct super_block *);
  86
  87static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  88                                                bool excl)
  89{
  90        int err;
  91        struct inode *inode;
  92        struct super_block *s = dir->i_sb;
  93        struct bfs_sb_info *info = BFS_SB(s);
  94        unsigned long ino;
  95
  96        inode = new_inode(s);
  97        if (!inode)
  98                return -ENOSPC;
  99        mutex_lock(&info->bfs_lock);
 100        ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
 101        if (ino > info->si_lasti) {
 102                mutex_unlock(&info->bfs_lock);
 103                iput(inode);
 104                return -ENOSPC;
 105        }
 106        set_bit(ino, info->si_imap);
 107        info->si_freei--;
 108        inode_init_owner(inode, dir, mode);
 109        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 110        inode->i_blocks = 0;
 111        inode->i_op = &bfs_file_inops;
 112        inode->i_fop = &bfs_file_operations;
 113        inode->i_mapping->a_ops = &bfs_aops;
 114        inode->i_ino = ino;
 115        BFS_I(inode)->i_dsk_ino = ino;
 116        BFS_I(inode)->i_sblock = 0;
 117        BFS_I(inode)->i_eblock = 0;
 118        insert_inode_hash(inode);
 119        mark_inode_dirty(inode);
 120        dump_imap("create", s);
 121
 122        err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
 123                                                        inode->i_ino);
 124        if (err) {
 125                inode_dec_link_count(inode);
 126                mutex_unlock(&info->bfs_lock);
 127                iput(inode);
 128                return err;
 129        }
 130        mutex_unlock(&info->bfs_lock);
 131        d_instantiate(dentry, inode);
 132        return 0;
 133}
 134
 135static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
 136                                                unsigned int flags)
 137{
 138        struct inode *inode = NULL;
 139        struct buffer_head *bh;
 140        struct bfs_dirent *de;
 141        struct bfs_sb_info *info = BFS_SB(dir->i_sb);
 142
 143        if (dentry->d_name.len > BFS_NAMELEN)
 144                return ERR_PTR(-ENAMETOOLONG);
 145
 146        mutex_lock(&info->bfs_lock);
 147        bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 148        if (bh) {
 149                unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
 150                brelse(bh);
 151                inode = bfs_iget(dir->i_sb, ino);
 152                if (IS_ERR(inode)) {
 153                        mutex_unlock(&info->bfs_lock);
 154                        return ERR_CAST(inode);
 155                }
 156        }
 157        mutex_unlock(&info->bfs_lock);
 158        d_add(dentry, inode);
 159        return NULL;
 160}
 161
 162static int bfs_link(struct dentry *old, struct inode *dir,
 163                                                struct dentry *new)
 164{
 165        struct inode *inode = old->d_inode;
 166        struct bfs_sb_info *info = BFS_SB(inode->i_sb);
 167        int err;
 168
 169        mutex_lock(&info->bfs_lock);
 170        err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
 171                                                        inode->i_ino);
 172        if (err) {
 173                mutex_unlock(&info->bfs_lock);
 174                return err;
 175        }
 176        inc_nlink(inode);
 177        inode->i_ctime = CURRENT_TIME_SEC;
 178        mark_inode_dirty(inode);
 179        ihold(inode);
 180        d_instantiate(new, inode);
 181        mutex_unlock(&info->bfs_lock);
 182        return 0;
 183}
 184
 185static int bfs_unlink(struct inode *dir, struct dentry *dentry)
 186{
 187        int error = -ENOENT;
 188        struct inode *inode = dentry->d_inode;
 189        struct buffer_head *bh;
 190        struct bfs_dirent *de;
 191        struct bfs_sb_info *info = BFS_SB(inode->i_sb);
 192
 193        mutex_lock(&info->bfs_lock);
 194        bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 195        if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
 196                goto out_brelse;
 197
 198        if (!inode->i_nlink) {
 199                printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
 200                                        inode->i_sb->s_id, inode->i_ino,
 201                                        inode->i_nlink);
 202                set_nlink(inode, 1);
 203        }
 204        de->ino = 0;
 205        mark_buffer_dirty_inode(bh, dir);
 206        dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 207        mark_inode_dirty(dir);
 208        inode->i_ctime = dir->i_ctime;
 209        inode_dec_link_count(inode);
 210        error = 0;
 211
 212out_brelse:
 213        brelse(bh);
 214        mutex_unlock(&info->bfs_lock);
 215        return error;
 216}
 217
 218static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 219                        struct inode *new_dir, struct dentry *new_dentry)
 220{
 221        struct inode *old_inode, *new_inode;
 222        struct buffer_head *old_bh, *new_bh;
 223        struct bfs_dirent *old_de, *new_de;
 224        struct bfs_sb_info *info;
 225        int error = -ENOENT;
 226
 227        old_bh = new_bh = NULL;
 228        old_inode = old_dentry->d_inode;
 229        if (S_ISDIR(old_inode->i_mode))
 230                return -EINVAL;
 231
 232        info = BFS_SB(old_inode->i_sb);
 233
 234        mutex_lock(&info->bfs_lock);
 235        old_bh = bfs_find_entry(old_dir, 
 236                                old_dentry->d_name.name, 
 237                                old_dentry->d_name.len, &old_de);
 238
 239        if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
 240                goto end_rename;
 241
 242        error = -EPERM;
 243        new_inode = new_dentry->d_inode;
 244        new_bh = bfs_find_entry(new_dir, 
 245                                new_dentry->d_name.name, 
 246                                new_dentry->d_name.len, &new_de);
 247
 248        if (new_bh && !new_inode) {
 249                brelse(new_bh);
 250                new_bh = NULL;
 251        }
 252        if (!new_bh) {
 253                error = bfs_add_entry(new_dir, 
 254                                        new_dentry->d_name.name,
 255                                        new_dentry->d_name.len,
 256                                        old_inode->i_ino);
 257                if (error)
 258                        goto end_rename;
 259        }
 260        old_de->ino = 0;
 261        old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 262        mark_inode_dirty(old_dir);
 263        if (new_inode) {
 264                new_inode->i_ctime = CURRENT_TIME_SEC;
 265                inode_dec_link_count(new_inode);
 266        }
 267        mark_buffer_dirty_inode(old_bh, old_dir);
 268        error = 0;
 269
 270end_rename:
 271        mutex_unlock(&info->bfs_lock);
 272        brelse(old_bh);
 273        brelse(new_bh);
 274        return error;
 275}
 276
 277const struct inode_operations bfs_dir_inops = {
 278        .create                 = bfs_create,
 279        .lookup                 = bfs_lookup,
 280        .link                   = bfs_link,
 281        .unlink                 = bfs_unlink,
 282        .rename                 = bfs_rename,
 283};
 284
 285static int bfs_add_entry(struct inode *dir, const unsigned char *name,
 286                                                        int namelen, int ino)
 287{
 288        struct buffer_head *bh;
 289        struct bfs_dirent *de;
 290        int block, sblock, eblock, off, pos;
 291        int i;
 292
 293        dprintf("name=%s, namelen=%d\n", name, namelen);
 294
 295        if (!namelen)
 296                return -ENOENT;
 297        if (namelen > BFS_NAMELEN)
 298                return -ENAMETOOLONG;
 299
 300        sblock = BFS_I(dir)->i_sblock;
 301        eblock = BFS_I(dir)->i_eblock;
 302        for (block = sblock; block <= eblock; block++) {
 303                bh = sb_bread(dir->i_sb, block);
 304                if (!bh)
 305                        return -ENOSPC;
 306                for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
 307                        de = (struct bfs_dirent *)(bh->b_data + off);
 308                        if (!de->ino) {
 309                                pos = (block - sblock) * BFS_BSIZE + off;
 310                                if (pos >= dir->i_size) {
 311                                        dir->i_size += BFS_DIRENT_SIZE;
 312                                        dir->i_ctime = CURRENT_TIME_SEC;
 313                                }
 314                                dir->i_mtime = CURRENT_TIME_SEC;
 315                                mark_inode_dirty(dir);
 316                                de->ino = cpu_to_le16((u16)ino);
 317                                for (i = 0; i < BFS_NAMELEN; i++)
 318                                        de->name[i] =
 319                                                (i < namelen) ? name[i] : 0;
 320                                mark_buffer_dirty_inode(bh, dir);
 321                                brelse(bh);
 322                                return 0;
 323                        }
 324                }
 325                brelse(bh);
 326        }
 327        return -ENOSPC;
 328}
 329
 330static inline int bfs_namecmp(int len, const unsigned char *name,
 331                                                        const char *buffer)
 332{
 333        if ((len < BFS_NAMELEN) && buffer[len])
 334                return 0;
 335        return !memcmp(name, buffer, len);
 336}
 337
 338static struct buffer_head *bfs_find_entry(struct inode *dir,
 339                        const unsigned char *name, int namelen,
 340                        struct bfs_dirent **res_dir)
 341{
 342        unsigned long block = 0, offset = 0;
 343        struct buffer_head *bh = NULL;
 344        struct bfs_dirent *de;
 345
 346        *res_dir = NULL;
 347        if (namelen > BFS_NAMELEN)
 348                return NULL;
 349
 350        while (block * BFS_BSIZE + offset < dir->i_size) {
 351                if (!bh) {
 352                        bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
 353                        if (!bh) {
 354                                block++;
 355                                continue;
 356                        }
 357                }
 358                de = (struct bfs_dirent *)(bh->b_data + offset);
 359                offset += BFS_DIRENT_SIZE;
 360                if (le16_to_cpu(de->ino) &&
 361                                bfs_namecmp(namelen, name, de->name)) {
 362                        *res_dir = de;
 363                        return bh;
 364                }
 365                if (offset < bh->b_size)
 366                        continue;
 367                brelse(bh);
 368                bh = NULL;
 369                offset = 0;
 370                block++;
 371        }
 372        brelse(bh);
 373        return NULL;
 374}
 375
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