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