fs/bfs/dir.c

   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/smp_lock.h>
  12 #include <linux/buffer_head.h>
  13 #include <linux/sched.h>
  14 #include "bfs.h"
  15
  16 #undef DEBUG
  17
  18 #ifdef DEBUG
  19 #define dprintf(x...)   printf(x)
  20 #else
  21 #define dprintf(x...)
  22 #endif
  23
  24 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
  25                                                 int namelen, int ino);
  26 static struct buffer_head *bfs_find_entry(struct inode *dir,
  27                                 const unsigned char *name, int namelen,
  28                                 struct bfs_dirent **res_dir);
  29
  30 static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
  31 {
  32         struct inode *dir = f->f_path.dentry->d_inode;
  33         struct buffer_head *bh;
  34         struct bfs_dirent *de;
  35         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
  36         unsigned int offset;
  37         int block;
  38
  39         mutex_lock(&info->bfs_lock);
  40
  41         if (f->f_pos & (BFS_DIRENT_SIZE - 1)) {
  42                 printf("Bad f_pos=%08lx for %s:%08lx\n",
  43                                         (unsigned long)f->f_pos,
  44                                         dir->i_sb->s_id, dir->i_ino);
  45                 mutex_unlock(&info->bfs_lock);
  46                 return -EBADF;
  47         }
  48
  49         while (f->f_pos < dir->i_size) {
  50                 offset = f->f_pos & (BFS_BSIZE - 1);
  51                 block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
  52                 bh = sb_bread(dir->i_sb, block);
  53                 if (!bh) {
  54                         f->f_pos += BFS_BSIZE - offset;
  55                         continue;
  56                 }
  57                 do {
  58                         de = (struct bfs_dirent *)(bh->b_data + offset);
  59                         if (de->ino) {
  60                                 int size = strnlen(de->name, BFS_NAMELEN);
  61                                 if (filldir(dirent, de->name, size, f->f_pos,
  62                                                 le16_to_cpu(de->ino),
  63                                                 DT_UNKNOWN) < 0) {
  64                                         brelse(bh);
  65                                         mutex_unlock(&info->bfs_lock);
  66                                         return 0;
  67                                 }
  68                         }
  69                         offset += BFS_DIRENT_SIZE;
  70                         f->f_pos += BFS_DIRENT_SIZE;
  71                 } while ((offset < BFS_BSIZE) && (f->f_pos < dir->i_size));
  72                 brelse(bh);
  73         }
  74
  75         mutex_unlock(&info->bfs_lock);
  76         return 0;
  77 }
  78
  79 const struct file_operations bfs_dir_operations = {
  80         .read           = generic_read_dir,
  81         .readdir        = bfs_readdir,
  82         .fsync          = file_fsync,
  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);
 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->i_uid = current->fsuid;
 109         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
 110         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 111         inode->i_blocks = 0;
 112         inode->i_op = &bfs_file_inops;
 113         inode->i_fop = &bfs_file_operations;
 114         inode->i_mapping->a_ops = &bfs_aops;
 115         inode->i_mode = mode;
 116         inode->i_ino = ino;
 117         BFS_I(inode)->i_dsk_ino = ino;
 118         BFS_I(inode)->i_sblock = 0;
 119         BFS_I(inode)->i_eblock = 0;
 120         insert_inode_hash(inode);
 121         mark_inode_dirty(inode);
 122         dump_imap("create", s);
 123
 124         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
 125                                                         inode->i_ino);
 126         if (err) {
 127                 inode_dec_link_count(inode);
 128                 iput(inode);
 129                 mutex_unlock(&info->bfs_lock);
 130                 return err;
 131         }
 132         mutex_unlock(&info->bfs_lock);
 133         d_instantiate(dentry, inode);
 134         return 0;
 135 }
 136
 137 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
 138                                                 struct nameidata *nd)
 139 {
 140         struct inode *inode = NULL;
 141         struct buffer_head *bh;
 142         struct bfs_dirent *de;
 143         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
 144
 145         if (dentry->d_name.len > BFS_NAMELEN)
 146                 return ERR_PTR(-ENAMETOOLONG);
 147
 148         mutex_lock(&info->bfs_lock);
 149         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 150         if (bh) {
 151                 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
 152                 brelse(bh);
 153                 inode = bfs_iget(dir->i_sb, ino);
 154                 if (IS_ERR(inode)) {
 155                         mutex_unlock(&info->bfs_lock);
 156                         return ERR_CAST(inode);
 157                 }
 158         }
 159         mutex_unlock(&info->bfs_lock);
 160         d_add(dentry, inode);
 161         return NULL;
 162 }
 163
 164 static int bfs_link(struct dentry *old, struct inode *dir,
 165                                                 struct dentry *new)
 166 {
 167         struct inode *inode = old->d_inode;
 168         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
 169         int err;
 170
 171         mutex_lock(&info->bfs_lock);
 172         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
 173                                                         inode->i_ino);
 174         if (err) {
 175                 mutex_unlock(&info->bfs_lock);
 176                 return err;
 177         }
 178         inc_nlink(inode);
 179         inode->i_ctime = CURRENT_TIME_SEC;
 180         mark_inode_dirty(inode);
 181         atomic_inc(&inode->i_count);
 182         d_instantiate(new, inode);
 183         mutex_unlock(&info->bfs_lock);
 184         return 0;
 185 }
 186
 187 static int bfs_unlink(struct inode *dir, struct dentry *dentry)
 188 {
 189         int error = -ENOENT;
 190         struct inode *inode = dentry->d_inode;
 191         struct buffer_head *bh;
 192         struct bfs_dirent *de;
 193         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
 194
 195         mutex_lock(&info->bfs_lock);
 196         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 197         if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
 198                 goto out_brelse;
 199
 200         if (!inode->i_nlink) {
 201                 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
 202                                         inode->i_sb->s_id, inode->i_ino,
 203                                         inode->i_nlink);
 204                 inode->i_nlink = 1;
 205         }
 206         de->ino = 0;
 207         mark_buffer_dirty(bh);
 208         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 209         mark_inode_dirty(dir);
 210         inode->i_ctime = dir->i_ctime;
 211         inode_dec_link_count(inode);
 212         error = 0;
 213
 214 out_brelse:
 215         brelse(bh);
 216         mutex_unlock(&info->bfs_lock);
 217         return error;
 218 }
 219
 220 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 221                         struct inode *new_dir, struct dentry *new_dentry)
 222 {
 223         struct inode *old_inode, *new_inode;
 224         struct buffer_head *old_bh, *new_bh;
 225         struct bfs_dirent *old_de, *new_de;
 226         struct bfs_sb_info *info;
 227         int error = -ENOENT;
 228
 229         old_bh = new_bh = NULL;
 230         old_inode = old_dentry->d_inode;
 231         if (S_ISDIR(old_inode->i_mode))
 232                 return -EINVAL;
 233
 234         info = BFS_SB(old_inode->i_sb);
 235
 236         mutex_lock(&info->bfs_lock);
 237         old_bh = bfs_find_entry(old_dir,
 238                                 old_dentry->d_name.name,
 239                                 old_dentry->d_name.len, &old_de);
 240
 241         if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
 242                 goto end_rename;
 243
 244         error = -EPERM;
 245         new_inode = new_dentry->d_inode;
 246         new_bh = bfs_find_entry(new_dir,
 247                                 new_dentry->d_name.name,
 248                                 new_dentry->d_name.len, &new_de);
 249
 250         if (new_bh && !new_inode) {
 251                 brelse(new_bh);
 252                 new_bh = NULL;
 253         }
 254         if (!new_bh) {
 255                 error = bfs_add_entry(new_dir,
 256                                         new_dentry->d_name.name,
 257                                         new_dentry->d_name.len,
 258                                         old_inode->i_ino);
 259                 if (error)
 260                         goto end_rename;
 261         }
 262         old_de->ino = 0;
 263         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 264         mark_inode_dirty(old_dir);
 265         if (new_inode) {
 266                 new_inode->i_ctime = CURRENT_TIME_SEC;
 267                 inode_dec_link_count(new_inode);
 268         }
 269         mark_buffer_dirty(old_bh);
 270         error = 0;
 271
 272 end_rename:
 273         mutex_unlock(&info->bfs_lock);
 274         brelse(old_bh);
 275         brelse(new_bh);
 276         return error;
 277 }
 278
 279 const struct inode_operations bfs_dir_inops = {
 280         .create                 = bfs_create,
 281         .lookup                 = bfs_lookup,
 282         .link                   = bfs_link,
 283         .unlink                 = bfs_unlink,
 284         .rename                 = bfs_rename,
 285 };
 286
 287 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
 288                                                         int namelen, int ino)
 289 {
 290         struct buffer_head *bh;
 291         struct bfs_dirent *de;
 292         int block, sblock, eblock, off, pos;
 293         int i;
 294
 295         dprintf("name=%s, namelen=%d\n", name, namelen);
 296
 297         if (!namelen)
 298                 return -ENOENT;
 299         if (namelen > BFS_NAMELEN)
 300                 return -ENAMETOOLONG;
 301
 302         sblock = BFS_I(dir)->i_sblock;
 303         eblock = BFS_I(dir)->i_eblock;
 304         for (block = sblock; block <= eblock; block++) {
 305                 bh = sb_bread(dir->i_sb, block);
 306                 if (!bh)
 307                         return -ENOSPC;
 308                 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
 309                         de = (struct bfs_dirent *)(bh->b_data + off);
 310                         if (!de->ino) {
 311                                 pos = (block - sblock) * BFS_BSIZE + off;
 312                                 if (pos >= dir->i_size) {
 313                                         dir->i_size += BFS_DIRENT_SIZE;
 314                                         dir->i_ctime = CURRENT_TIME_SEC;
 315                                 }
 316                                 dir->i_mtime = CURRENT_TIME_SEC;
 317                                 mark_inode_dirty(dir);
 318                                 de->ino = cpu_to_le16((u16)ino);
 319                                 for (i = 0; i < BFS_NAMELEN; i++)
 320                                         de->name[i] =
 321                                                 (i < namelen) ? name[i] : 0;
 322                                 mark_buffer_dirty(bh);
 323                                 brelse(bh);
 324                                 return 0;
 325                         }
 326                 }
 327                 brelse(bh);
 328         }
 329         return -ENOSPC;
 330 }
 331
 332 static inline int bfs_namecmp(int len, const unsigned char *name,
 333                                                         const char *buffer)
 334 {
 335         if ((len < BFS_NAMELEN) && buffer[len])
 336                 return 0;
 337         return !memcmp(name, buffer, len);
 338 }
 339
 340 static struct buffer_head *bfs_find_entry(struct inode *dir,
 341                         const unsigned char *name, int namelen,
 342                         struct bfs_dirent **res_dir)
 343 {
 344         unsigned long block = 0, offset = 0;
 345         struct buffer_head *bh = NULL;
 346         struct bfs_dirent *de;
 347
 348         *res_dir = NULL;
 349         if (namelen > BFS_NAMELEN)
 350                 return NULL;
 351
 352         while (block * BFS_BSIZE + offset < dir->i_size) {
 353                 if (!bh) {
 354                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
 355                         if (!bh) {
 356                                 block++;
 357                                 continue;
 358                         }
 359                 }
 360                 de = (struct bfs_dirent *)(bh->b_data + offset);
 361                 offset += BFS_DIRENT_SIZE;
 362                 if (le16_to_cpu(de->ino) &&
 363                                 bfs_namecmp(namelen, name, de->name)) {
 364                         *res_dir = de;
 365                         return bh;
 366                 }
 367                 if (offset < bh->b_size)
 368                         continue;
 369                 brelse(bh);
 370                 bh = NULL;
 371                 offset = 0;
 372                 block++;
 373         }
 374         brelse(bh);
 375         return NULL;
 376 }