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         unsigned int offset;
  36         int block;
  37
  38         lock_kernel();
  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                 unlock_kernel();
  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                                         unlock_kernel();
  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         unlock_kernel();
  75         return 0;
  76 }
  77
  78 const struct file_operations bfs_dir_operations = {
  79         .read           = generic_read_dir,
  80         .readdir        = bfs_readdir,
  81         .fsync          = file_fsync,
  82 };
  83
  84 extern void dump_imap(const char *, struct super_block *);
  85
  86 static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
  87                                                 struct nameidata *nd)
  88 {
  89         int err;
  90         struct inode *inode;
  91         struct super_block *s = dir->i_sb;
  92         struct bfs_sb_info *info = BFS_SB(s);
  93         unsigned long ino;
  94
  95         inode = new_inode(s);
  96         if (!inode)
  97                 return -ENOSPC;
  98         lock_kernel();
  99         ino = find_first_zero_bit(info->si_imap, info->si_lasti);
 100         if (ino > info->si_lasti) {
 101                 unlock_kernel();
 102                 iput(inode);
 103                 return -ENOSPC;
 104         }
 105         set_bit(ino, info->si_imap);
 106         info->si_freei--;
 107         inode->i_uid = current->fsuid;
 108         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
 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_mode = mode;
 115         inode->i_ino = ino;
 116         BFS_I(inode)->i_dsk_ino = ino;
 117         BFS_I(inode)->i_sblock = 0;
 118         BFS_I(inode)->i_eblock = 0;
 119         insert_inode_hash(inode);
 120         mark_inode_dirty(inode);
 121         dump_imap("create", s);
 122
 123         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
 124                                                         inode->i_ino);
 125         if (err) {
 126                 inode_dec_link_count(inode);
 127                 iput(inode);
 128                 unlock_kernel();
 129                 return err;
 130         }
 131         unlock_kernel();
 132         d_instantiate(dentry, inode);
 133         return 0;
 134 }
 135
 136 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
 137                                                 struct nameidata *nd)
 138 {
 139         struct inode *inode = NULL;
 140         struct buffer_head *bh;
 141         struct bfs_dirent *de;
 142
 143         if (dentry->d_name.len > BFS_NAMELEN)
 144                 return ERR_PTR(-ENAMETOOLONG);
 145
 146         lock_kernel();
 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                         unlock_kernel();
 154                         return ERR_CAST(inode);
 155                 }
 156         }
 157         unlock_kernel();
 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         int err;
 167
 168         lock_kernel();
 169         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
 170                                                         inode->i_ino);
 171         if (err) {
 172                 unlock_kernel();
 173                 return err;
 174         }
 175         inc_nlink(inode);
 176         inode->i_ctime = CURRENT_TIME_SEC;
 177         mark_inode_dirty(inode);
 178         atomic_inc(&inode->i_count);
 179         d_instantiate(new, inode);
 180         unlock_kernel();
 181         return 0;
 182 }
 183
 184 static int bfs_unlink(struct inode *dir, struct dentry *dentry)
 185 {
 186         int error = -ENOENT;
 187         struct inode *inode;
 188         struct buffer_head *bh;
 189         struct bfs_dirent *de;
 190
 191         inode = dentry->d_inode;
 192         lock_kernel();
 193         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 194         if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
 195                 goto out_brelse;
 196
 197         if (!inode->i_nlink) {
 198                 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
 199                                         inode->i_sb->s_id, inode->i_ino,
 200                                         inode->i_nlink);
 201                 inode->i_nlink = 1;
 202         }
 203         de->ino = 0;
 204         mark_buffer_dirty(bh);
 205         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 206         mark_inode_dirty(dir);
 207         inode->i_ctime = dir->i_ctime;
 208         inode_dec_link_count(inode);
 209         error = 0;
 210
 211 out_brelse:
 212         brelse(bh);
 213         unlock_kernel();
 214         return error;
 215 }
 216
 217 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 218                         struct inode *new_dir, struct dentry *new_dentry)
 219 {
 220         struct inode *old_inode, *new_inode;
 221         struct buffer_head *old_bh, *new_bh;
 222         struct bfs_dirent *old_de, *new_de;
 223         int error = -ENOENT;
 224
 225         old_bh = new_bh = NULL;
 226         old_inode = old_dentry->d_inode;
 227         if (S_ISDIR(old_inode->i_mode))
 228                 return -EINVAL;
 229
 230         lock_kernel();
 231         old_bh = bfs_find_entry(old_dir,
 232                                 old_dentry->d_name.name,
 233                                 old_dentry->d_name.len, &old_de);
 234
 235         if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
 236                 goto end_rename;
 237
 238         error = -EPERM;
 239         new_inode = new_dentry->d_inode;
 240         new_bh = bfs_find_entry(new_dir,
 241                                 new_dentry->d_name.name,
 242                                 new_dentry->d_name.len, &new_de);
 243
 244         if (new_bh && !new_inode) {
 245                 brelse(new_bh);
 246                 new_bh = NULL;
 247         }
 248         if (!new_bh) {
 249                 error = bfs_add_entry(new_dir,
 250                                         new_dentry->d_name.name,
 251                                         new_dentry->d_name.len,
 252                                         old_inode->i_ino);
 253                 if (error)
 254                         goto end_rename;
 255         }
 256         old_de->ino = 0;
 257         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 258         mark_inode_dirty(old_dir);
 259         if (new_inode) {
 260                 new_inode->i_ctime = CURRENT_TIME_SEC;
 261                 inode_dec_link_count(new_inode);
 262         }
 263         mark_buffer_dirty(old_bh);
 264         error = 0;
 265
 266 end_rename:
 267         unlock_kernel();
 268         brelse(old_bh);
 269         brelse(new_bh);
 270         return error;
 271 }
 272
 273 const struct inode_operations bfs_dir_inops = {
 274         .create                 = bfs_create,
 275         .lookup                 = bfs_lookup,
 276         .link                   = bfs_link,
 277         .unlink                 = bfs_unlink,
 278         .rename                 = bfs_rename,
 279 };
 280
 281 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
 282                                                         int namelen, int ino)
 283 {
 284         struct buffer_head *bh;
 285         struct bfs_dirent *de;
 286         int block, sblock, eblock, off, pos;
 287         int i;
 288
 289         dprintf("name=%s, namelen=%d\n", name, namelen);
 290
 291         if (!namelen)
 292                 return -ENOENT;
 293         if (namelen > BFS_NAMELEN)
 294                 return -ENAMETOOLONG;
 295
 296         sblock = BFS_I(dir)->i_sblock;
 297         eblock = BFS_I(dir)->i_eblock;
 298         for (block = sblock; block <= eblock; block++) {
 299                 bh = sb_bread(dir->i_sb, block);
 300                 if (!bh)
 301                         return -ENOSPC;
 302                 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
 303                         de = (struct bfs_dirent *)(bh->b_data + off);
 304                         if (!de->ino) {
 305                                 pos = (block - sblock) * BFS_BSIZE + off;
 306                                 if (pos >= dir->i_size) {
 307                                         dir->i_size += BFS_DIRENT_SIZE;
 308                                         dir->i_ctime = CURRENT_TIME_SEC;
 309                                 }
 310                                 dir->i_mtime = CURRENT_TIME_SEC;
 311                                 mark_inode_dirty(dir);
 312                                 de->ino = cpu_to_le16((u16)ino);
 313                                 for (i = 0; i < BFS_NAMELEN; i++)
 314                                         de->name[i] =
 315                                                 (i < namelen) ? name[i] : 0;
 316                                 mark_buffer_dirty(bh);
 317                                 brelse(bh);
 318                                 return 0;
 319                         }
 320                 }
 321                 brelse(bh);
 322         }
 323         return -ENOSPC;
 324 }
 325
 326 static inline int bfs_namecmp(int len, const unsigned char *name,
 327                                                         const char *buffer)
 328 {
 329         if ((len < BFS_NAMELEN) && buffer[len])
 330                 return 0;
 331         return !memcmp(name, buffer, len);
 332 }
 333
 334 static struct buffer_head *bfs_find_entry(struct inode *dir,
 335                         const unsigned char *name, int namelen,
 336                         struct bfs_dirent **res_dir)
 337 {
 338         unsigned long block = 0, offset = 0;
 339         struct buffer_head *bh = NULL;
 340         struct bfs_dirent *de;
 341
 342         *res_dir = NULL;
 343         if (namelen > BFS_NAMELEN)
 344                 return NULL;
 345
 346         while (block * BFS_BSIZE + offset < dir->i_size) {
 347                 if (!bh) {
 348                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
 349                         if (!bh) {
 350                                 block++;
 351                                 continue;
 352                         }
 353                 }
 354                 de = (struct bfs_dirent *)(bh->b_data + offset);
 355                 offset += BFS_DIRENT_SIZE;
 356                 if (le16_to_cpu(de->ino) &&
 357                                 bfs_namecmp(namelen, name, de->name)) {
 358                         *res_dir = de;
 359                         return bh;
 360                 }
 361                 if (offset < bh->b_size)
 362                         continue;
 363                 brelse(bh);
 364                 bh = NULL;
 365                 offset = 0;
 366                 block++;
 367         }
 368         brelse(bh);
 369         return NULL;
 370 }