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