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, int namelen, int ino);
  25 static struct buffer_head * bfs_find_entry(struct inode * dir,
  26         const unsigned char * name, int namelen, struct bfs_dirent ** res_dir);
  27
  28 static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir)
  29 {
  30         struct inode * dir = f->f_path.dentry->d_inode;
  31         struct buffer_head * bh;
  32         struct bfs_dirent * de;
  33         unsigned int offset;
  34         int block;
  35
  36         lock_kernel();
  37
  38         if (f->f_pos & (BFS_DIRENT_SIZE-1)) {
  39                 printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos,
  40                         dir->i_sb->s_id, dir->i_ino);
  41                 unlock_kernel();
  42                 return -EBADF;
  43         }
  44
  45         while (f->f_pos < dir->i_size) {
  46                 offset = f->f_pos & (BFS_BSIZE-1);
  47                 block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
  48                 bh = sb_bread(dir->i_sb, block);
  49                 if (!bh) {
  50                         f->f_pos += BFS_BSIZE - offset;
  51                         continue;
  52                 }
  53                 do {
  54                         de = (struct bfs_dirent *)(bh->b_data + offset);
  55                         if (de->ino) {
  56                                 int size = strnlen(de->name, BFS_NAMELEN);
  57                                 if (filldir(dirent, de->name, size, f->f_pos, le16_to_cpu(de->ino), DT_UNKNOWN) < 0) {
  58                                         brelse(bh);
  59                                         unlock_kernel();
  60                                         return 0;
  61                                 }
  62                         }
  63                         offset += BFS_DIRENT_SIZE;
  64                         f->f_pos += BFS_DIRENT_SIZE;
  65                 } while (offset < BFS_BSIZE && f->f_pos < dir->i_size);
  66                 brelse(bh);
  67         }
  68
  69         unlock_kernel();
  70         return 0;
  71 }
  72
  73 const struct file_operations bfs_dir_operations = {
  74         .read           = generic_read_dir,
  75         .readdir        = bfs_readdir,
  76         .fsync          = file_fsync,
  77 };
  78
  79 extern void dump_imap(const char *, struct super_block *);
  80
  81 static int bfs_create(struct inode * dir, struct dentry * dentry, int mode,
  82                 struct nameidata *nd)
  83 {
  84         int err;
  85         struct inode * inode;
  86         struct super_block * s = dir->i_sb;
  87         struct bfs_sb_info * info = BFS_SB(s);
  88         unsigned long ino;
  89
  90         inode = new_inode(s);
  91         if (!inode)
  92                 return -ENOSPC;
  93         lock_kernel();
  94         ino = find_first_zero_bit(info->si_imap, info->si_lasti);
  95         if (ino > info->si_lasti) {
  96                 unlock_kernel();
  97                 iput(inode);
  98                 return -ENOSPC;
  99         }
 100         set_bit(ino, info->si_imap);
 101         info->si_freei--;
 102         inode->i_uid = current->fsuid;
 103         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
 104         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 105         inode->i_blocks = 0;
 106         inode->i_op = &bfs_file_inops;
 107         inode->i_fop = &bfs_file_operations;
 108         inode->i_mapping->a_ops = &bfs_aops;
 109         inode->i_mode = mode;
 110         inode->i_ino = ino;
 111         BFS_I(inode)->i_dsk_ino = ino;
 112         BFS_I(inode)->i_sblock = 0;
 113         BFS_I(inode)->i_eblock = 0;
 114         insert_inode_hash(inode);
 115         mark_inode_dirty(inode);
 116         dump_imap("create",s);
 117
 118         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino);
 119         if (err) {
 120                 inode_dec_link_count(inode);
 121                 iput(inode);
 122                 unlock_kernel();
 123                 return err;
 124         }
 125         unlock_kernel();
 126         d_instantiate(dentry, inode);
 127         return 0;
 128 }
 129
 130 static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
 131 {
 132         struct inode * inode = NULL;
 133         struct buffer_head * bh;
 134         struct bfs_dirent * de;
 135
 136         if (dentry->d_name.len > BFS_NAMELEN)
 137                 return ERR_PTR(-ENAMETOOLONG);
 138
 139         lock_kernel();
 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 = iget(dir->i_sb, ino);
 145                 if (!inode) {
 146                         unlock_kernel();
 147                         return ERR_PTR(-EACCES);
 148                 }
 149         }
 150         unlock_kernel();
 151         d_add(dentry, inode);
 152         return NULL;
 153 }
 154
 155 static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new)
 156 {
 157         struct inode * inode = old->d_inode;
 158         int err;
 159
 160         lock_kernel();
 161         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
 162         if (err) {
 163                 unlock_kernel();
 164                 return err;
 165         }
 166         inc_nlink(inode);
 167         inode->i_ctime = CURRENT_TIME_SEC;
 168         mark_inode_dirty(inode);
 169         atomic_inc(&inode->i_count);
 170         d_instantiate(new, inode);
 171         unlock_kernel();
 172         return 0;
 173 }
 174
 175
 176 static int bfs_unlink(struct inode * dir, struct dentry * dentry)
 177 {
 178         int error = -ENOENT;
 179         struct inode * inode;
 180         struct buffer_head * bh;
 181         struct bfs_dirent * de;
 182
 183         inode = dentry->d_inode;
 184         lock_kernel();
 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", inode->i_sb->s_id,
 191                                 inode->i_ino, inode->i_nlink);
 192                 inode->i_nlink = 1;
 193         }
 194         de->ino = 0;
 195         mark_buffer_dirty(bh);
 196         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 197         mark_inode_dirty(dir);
 198         inode->i_ctime = dir->i_ctime;
 199         inode_dec_link_count(inode);
 200         error = 0;
 201
 202 out_brelse:
 203         brelse(bh);
 204         unlock_kernel();
 205         return error;
 206 }
 207
 208 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
 209                         struct inode * new_dir, struct dentry * new_dentry)
 210 {
 211         struct inode * old_inode, * new_inode;
 212         struct buffer_head * old_bh, * new_bh;
 213         struct bfs_dirent * old_de, * new_de;
 214         int error = -ENOENT;
 215
 216         old_bh = new_bh = NULL;
 217         old_inode = old_dentry->d_inode;
 218         if (S_ISDIR(old_inode->i_mode))
 219                 return -EINVAL;
 220
 221         lock_kernel();
 222         old_bh = bfs_find_entry(old_dir,
 223                                 old_dentry->d_name.name,
 224                                 old_dentry->d_name.len, &old_de);
 225
 226         if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino)
 227                 goto end_rename;
 228
 229         error = -EPERM;
 230         new_inode = new_dentry->d_inode;
 231         new_bh = bfs_find_entry(new_dir,
 232                                 new_dentry->d_name.name,
 233                                 new_dentry->d_name.len, &new_de);
 234
 235         if (new_bh && !new_inode) {
 236                 brelse(new_bh);
 237                 new_bh = NULL;
 238         }
 239         if (!new_bh) {
 240                 error = bfs_add_entry(new_dir,
 241                                         new_dentry->d_name.name,
 242                                         new_dentry->d_name.len, old_inode->i_ino);
 243                 if (error)
 244                         goto end_rename;
 245         }
 246         old_de->ino = 0;
 247         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 248         mark_inode_dirty(old_dir);
 249         if (new_inode) {
 250                 new_inode->i_ctime = CURRENT_TIME_SEC;
 251                 inode_dec_link_count(new_inode);
 252         }
 253         mark_buffer_dirty(old_bh);
 254         error = 0;
 255
 256 end_rename:
 257         unlock_kernel();
 258         brelse(old_bh);
 259         brelse(new_bh);
 260         return error;
 261 }
 262
 263 const struct inode_operations bfs_dir_inops = {
 264         .create                 = bfs_create,
 265         .lookup                 = bfs_lookup,
 266         .link                   = bfs_link,
 267         .unlink                 = bfs_unlink,
 268         .rename                 = bfs_rename,
 269 };
 270
 271 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino)
 272 {
 273         struct buffer_head * bh;
 274         struct bfs_dirent * de;
 275         int block, sblock, eblock, off, eoff;
 276         int i;
 277
 278         dprintf("name=%s, namelen=%d\n", name, namelen);
 279
 280         if (!namelen)
 281                 return -ENOENT;
 282         if (namelen > BFS_NAMELEN)
 283                 return -ENAMETOOLONG;
 284
 285         sblock = BFS_I(dir)->i_sblock;
 286         eblock = BFS_I(dir)->i_eblock;
 287         eoff = dir->i_size % BFS_BSIZE;
 288         for (block=sblock; block<=eblock; block++) {
 289                 bh = sb_bread(dir->i_sb, block);
 290                 if(!bh)
 291                         return -ENOSPC;
 292                 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
 293                         de = (struct bfs_dirent *)(bh->b_data + off);
 294                         if (block==eblock && off>=eoff) {
 295                                 /* Do not read/interpret the garbage in the end of eblock. */
 296                                 de->ino = 0;
 297                         }
 298                         if (!de->ino) {
 299                                 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
 300                                         dir->i_size += BFS_DIRENT_SIZE;
 301                                         dir->i_ctime = CURRENT_TIME_SEC;
 302                                 }
 303                                 dir->i_mtime = CURRENT_TIME_SEC;
 304                                 mark_inode_dirty(dir);
 305                                 de->ino = cpu_to_le16((u16)ino);
 306                                 for (i=0; i<BFS_NAMELEN; i++)
 307                                         de->name[i] = (i < namelen) ? name[i] : 0;
 308                                 mark_buffer_dirty(bh);
 309                                 brelse(bh);
 310                                 return 0;
 311                         }
 312                 }
 313                 brelse(bh);
 314         }
 315         return -ENOSPC;
 316 }
 317
 318 static inline int bfs_namecmp(int len, const unsigned char * name, const char * buffer)
 319 {
 320         if (len < BFS_NAMELEN && buffer[len])
 321                 return 0;
 322         return !memcmp(name, buffer, len);
 323 }
 324
 325 static struct buffer_head * bfs_find_entry(struct inode * dir,
 326         const unsigned char * name, int namelen, struct bfs_dirent ** res_dir)
 327 {
 328         unsigned long block, offset;
 329         struct buffer_head * bh;
 330         struct bfs_dirent * de;
 331
 332         *res_dir = NULL;
 333         if (namelen > BFS_NAMELEN)
 334                 return NULL;
 335         bh = NULL;
 336         block = offset = 0;
 337         while (block * BFS_BSIZE + offset < dir->i_size) {
 338                 if (!bh) {
 339                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
 340                         if (!bh) {
 341                                 block++;
 342                                 continue;
 343                         }
 344                 }
 345                 de = (struct bfs_dirent *)(bh->b_data + offset);
 346                 offset += BFS_DIRENT_SIZE;
 347                 if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) {
 348                         *res_dir = de;
 349                         return bh;
 350                 }
 351                 if (offset < bh->b_size)
 352                         continue;
 353                 brelse(bh);
 354                 bh = NULL;
 355                 offset = 0;
 356                 block++;
 357         }
 358         brelse(bh);
 359         return NULL;
 360 }