i386/linux-2.3.21/fs/efs/namei.c

   1 /*
   2  * namei.c
   3  *
   4  * Copyright (c) 1999 Al Smith
   5  *
   6  * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
   7  */
   8
   9 #include <linux/string.h>
  10 #include <linux/efs_fs.h>
  11
  12 static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
  13         struct buffer_head *bh;
  14
  15         int                     slot, namelen;
  16         char                    *nameptr;
  17         struct efs_dir          *dirblock;
  18         struct efs_dentry       *dirslot;
  19         efs_ino_t               inodenum;
  20         efs_block_t             block;
  21
  22         if (inode->i_size & (EFS_DIRBSIZE-1))
  23                 printk(KERN_WARNING "EFS: WARNING: find_entry(): directory size not a multiple of EFS_DIRBSIZE\n");
  24
  25         for(block = 0; block < inode->i_blocks; block++) {
  26
  27                 bh = bread(inode->i_dev, efs_bmap(inode, block), EFS_DIRBSIZE);
  28                 if (!bh) {
  29                         printk(KERN_ERR "EFS: find_entry(): failed to read dir block %d\n", block);
  30                         return 0;
  31                 }
  32
  33                 dirblock = (struct efs_dir *) bh->b_data;
  34
  35                 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
  36                         printk(KERN_ERR "EFS: find_entry(): invalid directory block\n");
  37                         brelse(bh);
  38                         return(0);
  39                 }
  40
  41                 for(slot = 0; slot < dirblock->slots; slot++) {
  42                         dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
  43
  44                         namelen  = dirslot->namelen;
  45                         nameptr  = dirslot->name;
  46
  47                         if ((namelen == len) && (!memcmp(name, nameptr, len))) {
  48                                 inodenum = be32_to_cpu(dirslot->inode);
  49                                 brelse(bh);
  50                                 return(inodenum);
  51                         }
  52                 }
  53                 brelse(bh);
  54         }
  55         return(0);
  56 }
  57
  58 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry) {
  59         efs_ino_t inodenum;
  60         struct inode * inode;
  61
  62         if (!dir || !S_ISDIR(dir->i_mode))
  63                 return ERR_PTR(-ENOENT);
  64
  65         inode = NULL;
  66
  67         inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
  68         if (inodenum) {
  69                 if (!(inode = iget(dir->i_sb, inodenum)))
  70                         return ERR_PTR(-EACCES);
  71         }
  72
  73         d_add(dentry, inode);
  74         return NULL;
  75 }
  76