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         .llseek         = generic_file_llseek,
  84 };
  85
  86 extern void dump_imap(const char *, struct super_block *);
  87
  88 static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
  89                                                 struct nameidata *nd)
  90 {
  91         int err;
  92         struct inode *inode;
  93         struct super_block *s = dir->i_sb;
  94         struct bfs_sb_info *info = BFS_SB(s);
  95         unsigned long ino;
  96
  97         inode = new_inode(s);
  98         if (!inode)
  99                 return -ENOSPC;
 100         mutex_lock(&info->bfs_lock);
 101         ino = find_first_zero_bit(info->si_imap, info->si_lasti);
 102         if (ino > info->si_lasti) {
 103                 mutex_unlock(&info->bfs_lock);
 104                 iput(inode);
 105                 return -ENOSPC;
 106         }
 107         set_bit(ino, info->si_imap);
 108         info->si_freei--;
 109         inode->i_uid = current_fsuid();
 110         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current_fsgid();
 111         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 112         inode->i_blocks = 0;
 113         inode->i_op = &bfs_file_inops;
 114         inode->i_fop = &bfs_file_operations;
 115         inode->i_mapping->a_ops = &bfs_aops;
 116         inode->i_mode = mode;
 117         inode->i_ino = ino;
 118         BFS_I(inode)->i_dsk_ino = ino;
 119         BFS_I(inode)->i_sblock = 0;
 120         BFS_I(inode)->i_eblock = 0;
 121         insert_inode_hash(inode);
 122         mark_inode_dirty(inode);
 123         dump_imap("create", s);
 124
 125         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
 126                                                         inode->i_ino);
 127         if (err) {
 128                 inode_dec_link_count(inode);
 129                 mutex_unlock(&info->bfs_lock);
 130                 iput(inode);
 131                 return err;
 132         }
 133         mutex_unlock(&info->bfs_lock);
 134         d_instantiate(dentry, inode);
 135         return 0;
 136 }
 137
 138 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
 139                                                 struct nameidata *nd)
 140 {
 141         struct inode *inode = NULL;
 142         struct buffer_head *bh;
 143         struct bfs_dirent *de;
 144         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
 145
 146         if (dentry->d_name.len > BFS_NAMELEN)
 147                 return ERR_PTR(-ENAMETOOLONG);
 148
 149         mutex_lock(&info->bfs_lock);
 150         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 151         if (bh) {
 152                 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
 153                 brelse(bh);
 154                 inode = bfs_iget(dir->i_sb, ino);
 155                 if (IS_ERR(inode)) {
 156                         mutex_unlock(&info->bfs_lock);
 157                         return ERR_CAST(inode);
 158                 }
 159         }
 160         mutex_unlock(&info->bfs_lock);
 161         d_add(dentry, inode);
 162         return NULL;
 163 }
 164
 165 static int bfs_link(struct dentry *old, struct inode *dir,
 166                                                 struct dentry *new)
 167 {
 168         struct inode *inode = old->d_inode;
 169         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
 170         int err;
 171
 172         mutex_lock(&info->bfs_lock);
 173         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
 174                                                         inode->i_ino);
 175         if (err) {
 176                 mutex_unlock(&info->bfs_lock);
 177                 return err;
 178         }
 179         inc_nlink(inode);
 180         inode->i_ctime = CURRENT_TIME_SEC;
 181         mark_inode_dirty(inode);
 182         atomic_inc(&inode->i_count);
 183         d_instantiate(new, inode);
 184         mutex_unlock(&info->bfs_lock);
 185         return 0;
 186 }
 187
 188 static int bfs_unlink(struct inode *dir, struct dentry *dentry)
 189 {
 190         int error = -ENOENT;
 191         struct inode *inode = dentry->d_inode;
 192         struct buffer_head *bh;
 193         struct bfs_dirent *de;
 194         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
 195
 196         mutex_lock(&info->bfs_lock);
 197         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 198         if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
 199                 goto out_brelse;
 200
 201         if (!inode->i_nlink) {
 202                 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
 203                                         inode->i_sb->s_id, inode->i_ino,
 204                                         inode->i_nlink);
 205                 inode->i_nlink = 1;
 206         }
 207         de->ino = 0;
 208         mark_buffer_dirty(bh);
 209         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 210         mark_inode_dirty(dir);
 211         inode->i_ctime = dir->i_ctime;
 212         inode_dec_link_count(inode);
 213         error = 0;
 214
 215 out_brelse:
 216         brelse(bh);
 217         mutex_unlock(&info->bfs_lock);
 218         return error;
 219 }
 220
 221 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 222                         struct inode *new_dir, struct dentry *new_dentry)
 223 {
 224         struct inode *old_inode, *new_inode;
 225         struct buffer_head *old_bh, *new_bh;
 226         struct bfs_dirent *old_de, *new_de;
 227         struct bfs_sb_info *info;
 228         int error = -ENOENT;
 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(old_bh);
 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(bh);
 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 }