fs/bfs/dir.c

   1 /*
   2  *      fs/bfs/dir.c
   3  *      BFS directory operations.
   4  *      Copyright (C) 1999,2000  Tigran Aivazian <[email protected]>
   5  *      Made endianness-clean by Andrew Stribblehill <[email protected]> 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
  23 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
  24                                                 int namelen, int ino);
  25 static struct buffer_head *bfs_find_entry(struct inode *dir,
  26                                 const unsigned char *name, int namelen,
  27                                 struct bfs_dirent **res_dir);
  28
  29 static 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
  78 const 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
  85 extern void dump_imap(const char *, struct super_block *);
  86
  87 static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
  88                                                 struct nameidata *nd)
  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
 135 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
 136                                                 struct nameidata *nd)
 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
 162 static 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
 185 static 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                 inode->i_nlink = 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
 212 out_brelse:
 213         brelse(bh);
 214         mutex_unlock(&info->bfs_lock);
 215         return error;
 216 }
 217
 218 static 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         if (new_dentry->d_inode && S_ISDIR(new_dentry->d_inode->i_mode))
 228                 dentry_unhash(new_dentry);
 229
 230         old_bh = new_bh = NULL;
 231         old_inode = old_dentry->d_inode;
 232         if (S_ISDIR(old_inode->i_mode))
 233                 return -EINVAL;
 234
 235         info = BFS_SB(old_inode->i_sb);
 236
 237         mutex_lock(&info->bfs_lock);
 238         old_bh = bfs_find_entry(old_dir,
 239                                 old_dentry->d_name.name,
 240                                 old_dentry->d_name.len, &old_de);
 241
 242         if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
 243                 goto end_rename;
 244
 245         error = -EPERM;
 246         new_inode = new_dentry->d_inode;
 247         new_bh = bfs_find_entry(new_dir,
 248                                 new_dentry->d_name.name,
 249                                 new_dentry->d_name.len, &new_de);
 250
 251         if (new_bh && !new_inode) {
 252                 brelse(new_bh);
 253                 new_bh = NULL;
 254         }
 255         if (!new_bh) {
 256                 error = bfs_add_entry(new_dir,
 257                                         new_dentry->d_name.name,
 258                                         new_dentry->d_name.len,
 259                                         old_inode->i_ino);
 260                 if (error)
 261                         goto end_rename;
 262         }
 263         old_de->ino = 0;
 264         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 265         mark_inode_dirty(old_dir);
 266         if (new_inode) {
 267                 new_inode->i_ctime = CURRENT_TIME_SEC;
 268                 inode_dec_link_count(new_inode);
 269         }
 270         mark_buffer_dirty_inode(old_bh, old_dir);
 271         error = 0;
 272
 273 end_rename:
 274         mutex_unlock(&info->bfs_lock);
 275         brelse(old_bh);
 276         brelse(new_bh);
 277         return error;
 278 }
 279
 280 const struct inode_operations bfs_dir_inops = {
 281         .create                 = bfs_create,
 282         .lookup                 = bfs_lookup,
 283         .link                   = bfs_link,
 284         .unlink                 = bfs_unlink,
 285         .rename                 = bfs_rename,
 286 };
 287
 288 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
 289                                                         int namelen, int ino)
 290 {
 291         struct buffer_head *bh;
 292         struct bfs_dirent *de;
 293         int block, sblock, eblock, off, pos;
 294         int i;
 295
 296         dprintf("name=%s, namelen=%d\n", name, namelen);
 297
 298         if (!namelen)
 299                 return -ENOENT;
 300         if (namelen > BFS_NAMELEN)
 301                 return -ENAMETOOLONG;
 302
 303         sblock = BFS_I(dir)->i_sblock;
 304         eblock = BFS_I(dir)->i_eblock;
 305         for (block = sblock; block <= eblock; block++) {
 306                 bh = sb_bread(dir->i_sb, block);
 307                 if (!bh)
 308                         return -ENOSPC;
 309                 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
 310                         de = (struct bfs_dirent *)(bh->b_data + off);
 311                         if (!de->ino) {
 312                                 pos = (block - sblock) * BFS_BSIZE + off;
 313                                 if (pos >= dir->i_size) {
 314                                         dir->i_size += BFS_DIRENT_SIZE;
 315                                         dir->i_ctime = CURRENT_TIME_SEC;
 316                                 }
 317                                 dir->i_mtime = CURRENT_TIME_SEC;
 318                                 mark_inode_dirty(dir);
 319                                 de->ino = cpu_to_le16((u16)ino);
 320                                 for (i = 0; i < BFS_NAMELEN; i++)
 321                                         de->name[i] =
 322                                                 (i < namelen) ? name[i] : 0;
 323                                 mark_buffer_dirty_inode(bh, dir);
 324                                 brelse(bh);
 325                                 return 0;
 326                         }
 327                 }
 328                 brelse(bh);
 329         }
 330         return -ENOSPC;
 331 }
 332
 333 static inline int bfs_namecmp(int len, const unsigned char *name,
 334                                                         const char *buffer)
 335 {
 336         if ((len < BFS_NAMELEN) && buffer[len])
 337                 return 0;
 338         return !memcmp(name, buffer, len);
 339 }
 340
 341 static struct buffer_head *bfs_find_entry(struct inode *dir,
 342                         const unsigned char *name, int namelen,
 343                         struct bfs_dirent **res_dir)
 344 {
 345         unsigned long block = 0, offset = 0;
 346         struct buffer_head *bh = NULL;
 347         struct bfs_dirent *de;
 348
 349         *res_dir = NULL;
 350         if (namelen > BFS_NAMELEN)
 351                 return NULL;
 352
 353         while (block * BFS_BSIZE + offset < dir->i_size) {
 354                 if (!bh) {
 355                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
 356                         if (!bh) {
 357                                 block++;
 358                                 continue;
 359                         }
 360                 }
 361                 de = (struct bfs_dirent *)(bh->b_data + offset);
 362                 offset += BFS_DIRENT_SIZE;
 363                 if (le16_to_cpu(de->ino) &&
 364                                 bfs_namecmp(namelen, name, de->name)) {
 365                         *res_dir = de;
 366                         return bh;
 367                 }
 368                 if (offset < bh->b_size)
 369                         continue;
 370                 brelse(bh);
 371                 bh = NULL;
 372                 offset = 0;
 373                 block++;
 374         }
 375         brelse(bh);
 376         return NULL;
 377 }