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/buffer_head.h>
  10 #include <linux/string.h>
  11 #include <linux/efs_fs.h>
  12 #include <linux/smp_lock.h>
  13
  14 static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
  15         struct buffer_head *bh;
  16
  17         int                     slot, namelen;
  18         char                    *nameptr;
  19         struct efs_dir          *dirblock;
  20         struct efs_dentry       *dirslot;
  21         efs_ino_t               inodenum;
  22         efs_block_t             block;
  23
  24         if (inode->i_size & (EFS_DIRBSIZE-1))
  25                 printk(KERN_WARNING "EFS: WARNING: find_entry(): directory size not a multiple of EFS_DIRBSIZE\n");
  26
  27         for(block = 0; block < inode->i_blocks; block++) {
  28
  29                 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
  30                 if (!bh) {
  31                         printk(KERN_ERR "EFS: find_entry(): failed to read dir block %d\n", block);
  32                         return 0;
  33                 }
  34
  35                 dirblock = (struct efs_dir *) bh->b_data;
  36
  37                 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
  38                         printk(KERN_ERR "EFS: find_entry(): invalid directory block\n");
  39                         brelse(bh);
  40                         return(0);
  41                 }
  42
  43                 for(slot = 0; slot < dirblock->slots; slot++) {
  44                         dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
  45
  46                         namelen  = dirslot->namelen;
  47                         nameptr  = dirslot->name;
  48
  49                         if ((namelen == len) && (!memcmp(name, nameptr, len))) {
  50                                 inodenum = be32_to_cpu(dirslot->inode);
  51                                 brelse(bh);
  52                                 return(inodenum);
  53                         }
  54                 }
  55                 brelse(bh);
  56         }
  57         return(0);
  58 }
  59
  60 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) {
  61         efs_ino_t inodenum;
  62         struct inode * inode = NULL;
  63
  64         lock_kernel();
  65         inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
  66         if (inodenum) {
  67                 if (!(inode = iget(dir->i_sb, inodenum))) {
  68                         unlock_kernel();
  69                         return ERR_PTR(-EACCES);
  70                 }
  71         }
  72         unlock_kernel();
  73
  74         d_add(dentry, inode);
  75         return NULL;
  76 }
  77
  78 struct dentry *efs_get_parent(struct dentry *child)
  79 {
  80         struct dentry *parent;
  81         struct inode *inode;
  82         efs_ino_t ino;
  83         int error;
  84
  85         lock_kernel();
  86
  87         error = -ENOENT;
  88         ino = efs_find_entry(child->d_inode, "..", 2);
  89         if (!ino)
  90                 goto fail;
  91
  92         error = -EACCES;
  93         inode = iget(child->d_inode->i_sb, ino);
  94         if (!inode)
  95                 goto fail;
  96
  97         error = -ENOMEM;
  98         parent = d_alloc_anon(inode);
  99         if (!parent)
 100                 goto fail_iput;
 101
 102         unlock_kernel();
 103         return parent;
 104
 105  fail_iput:
 106         iput(inode);
 107  fail:
 108         unlock_kernel();
 109         return ERR_PTR(error);
 110 }