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_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 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 = inode->i_blksize = 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->i_nlink--;
 121                 mark_inode_dirty(inode);
 122                 iput(inode);
 123                 unlock_kernel();
 124                 return err;
 125         }
 126         unlock_kernel();
 127         d_instantiate(dentry, inode);
 128         return 0;
 129 }
 130
 131 static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
 132 {
 133         struct inode * inode = NULL;
 134         struct buffer_head * bh;
 135         struct bfs_dirent * de;
 136
 137         if (dentry->d_name.len > BFS_NAMELEN)
 138                 return ERR_PTR(-ENAMETOOLONG);
 139
 140         lock_kernel();
 141         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 142         if (bh) {
 143                 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
 144                 brelse(bh);
 145                 inode = iget(dir->i_sb, ino);
 146                 if (!inode) {
 147                         unlock_kernel();
 148                         return ERR_PTR(-EACCES);
 149                 }
 150         }
 151         unlock_kernel();
 152         d_add(dentry, inode);
 153         return NULL;
 154 }
 155
 156 static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new)
 157 {
 158         struct inode * inode = old->d_inode;
 159         int err;
 160
 161         lock_kernel();
 162         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
 163         if (err) {
 164                 unlock_kernel();
 165                 return err;
 166         }
 167         inode->i_nlink++;
 168         inode->i_ctime = CURRENT_TIME_SEC;
 169         mark_inode_dirty(inode);
 170         atomic_inc(&inode->i_count);
 171         d_instantiate(new, inode);
 172         unlock_kernel();
 173         return 0;
 174 }
 175
 176
 177 static int bfs_unlink(struct inode * dir, struct dentry * dentry)
 178 {
 179         int error = -ENOENT;
 180         struct inode * inode;
 181         struct buffer_head * bh;
 182         struct bfs_dirent * de;
 183
 184         inode = dentry->d_inode;
 185         lock_kernel();
 186         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 187         if (!bh || le16_to_cpu(de->ino) != inode->i_ino)
 188                 goto out_brelse;
 189
 190         if (!inode->i_nlink) {
 191                 printf("unlinking non-existent file %s:%lu (nlink=%d)\n", inode->i_sb->s_id,
 192                                 inode->i_ino, inode->i_nlink);
 193                 inode->i_nlink = 1;
 194         }
 195         de->ino = 0;
 196         mark_buffer_dirty(bh);
 197         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 198         mark_inode_dirty(dir);
 199         inode->i_nlink--;
 200         inode->i_ctime = dir->i_ctime;
 201         mark_inode_dirty(inode);
 202         error = 0;
 203
 204 out_brelse:
 205         brelse(bh);
 206         unlock_kernel();
 207         return error;
 208 }
 209
 210 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
 211                         struct inode * new_dir, struct dentry * new_dentry)
 212 {
 213         struct inode * old_inode, * new_inode;
 214         struct buffer_head * old_bh, * new_bh;
 215         struct bfs_dirent * old_de, * new_de;
 216         int error = -ENOENT;
 217
 218         old_bh = new_bh = NULL;
 219         old_inode = old_dentry->d_inode;
 220         if (S_ISDIR(old_inode->i_mode))
 221                 return -EINVAL;
 222
 223         lock_kernel();
 224         old_bh = bfs_find_entry(old_dir,
 225                                 old_dentry->d_name.name,
 226                                 old_dentry->d_name.len, &old_de);
 227
 228         if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino)
 229                 goto end_rename;
 230
 231         error = -EPERM;
 232         new_inode = new_dentry->d_inode;
 233         new_bh = bfs_find_entry(new_dir,
 234                                 new_dentry->d_name.name,
 235                                 new_dentry->d_name.len, &new_de);
 236
 237         if (new_bh && !new_inode) {
 238                 brelse(new_bh);
 239                 new_bh = NULL;
 240         }
 241         if (!new_bh) {
 242                 error = bfs_add_entry(new_dir,
 243                                         new_dentry->d_name.name,
 244                                         new_dentry->d_name.len, old_inode->i_ino);
 245                 if (error)
 246                         goto end_rename;
 247         }
 248         old_de->ino = 0;
 249         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 250         mark_inode_dirty(old_dir);
 251         if (new_inode) {
 252                 new_inode->i_nlink--;
 253                 new_inode->i_ctime = CURRENT_TIME_SEC;
 254                 mark_inode_dirty(new_inode);
 255         }
 256         mark_buffer_dirty(old_bh);
 257         error = 0;
 258
 259 end_rename:
 260         unlock_kernel();
 261         brelse(old_bh);
 262         brelse(new_bh);
 263         return error;
 264 }
 265
 266 struct inode_operations bfs_dir_inops = {
 267         .create                 = bfs_create,
 268         .lookup                 = bfs_lookup,
 269         .link                   = bfs_link,
 270         .unlink                 = bfs_unlink,
 271         .rename                 = bfs_rename,
 272 };
 273
 274 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino)
 275 {
 276         struct buffer_head * bh;
 277         struct bfs_dirent * de;
 278         int block, sblock, eblock, off, eoff;
 279         int i;
 280
 281         dprintf("name=%s, namelen=%d\n", name, namelen);
 282
 283         if (!namelen)
 284                 return -ENOENT;
 285         if (namelen > BFS_NAMELEN)
 286                 return -ENAMETOOLONG;
 287
 288         sblock = BFS_I(dir)->i_sblock;
 289         eblock = BFS_I(dir)->i_eblock;
 290         eoff = dir->i_size % BFS_BSIZE;
 291         for (block=sblock; block<=eblock; block++) {
 292                 bh = sb_bread(dir->i_sb, block);
 293                 if(!bh)
 294                         return -ENOSPC;
 295                 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
 296                         de = (struct bfs_dirent *)(bh->b_data + off);
 297                         if (block==eblock && off>=eoff) {
 298                                 /* Do not read/interpret the garbage in the end of eblock. */
 299                                 de->ino = 0;
 300                         }
 301                         if (!de->ino) {
 302                                 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
 303                                         dir->i_size += BFS_DIRENT_SIZE;
 304                                         dir->i_ctime = CURRENT_TIME_SEC;
 305                                 }
 306                                 dir->i_mtime = CURRENT_TIME_SEC;
 307                                 mark_inode_dirty(dir);
 308                                 de->ino = cpu_to_le16((u16)ino);
 309                                 for (i=0; i<BFS_NAMELEN; i++)
 310                                         de->name[i] = (i < namelen) ? name[i] : 0;
 311                                 mark_buffer_dirty(bh);
 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, const char * buffer)
 322 {
 323         if (len < BFS_NAMELEN && buffer[len])
 324                 return 0;
 325         return !memcmp(name, buffer, len);
 326 }
 327
 328 static struct buffer_head * bfs_find_entry(struct inode * dir,
 329         const unsigned char * name, int namelen, struct bfs_dirent ** res_dir)
 330 {
 331         unsigned long block, offset;
 332         struct buffer_head * bh;
 333         struct bfs_dirent * de;
 334
 335         *res_dir = NULL;
 336         if (namelen > BFS_NAMELEN)
 337                 return NULL;
 338         bh = NULL;
 339         block = offset = 0;
 340         while (block * BFS_BSIZE + offset < dir->i_size) {
 341                 if (!bh) {
 342                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
 343                         if (!bh) {
 344                                 block++;
 345                                 continue;
 346                         }
 347                 }
 348                 de = (struct bfs_dirent *)(bh->b_data + offset);
 349                 offset += BFS_DIRENT_SIZE;
 350                 if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) {
 351                         *res_dir = de;
 352                         return bh;
 353                 }
 354                 if (offset < bh->b_size)
 355                         continue;
 356                 brelse(bh);
 357                 bh = NULL;
 358                 offset = 0;
 359                 block++;
 360         }
 361         brelse(bh);
 362         return NULL;
 363 }