release/src-rt-6.x.4708/linux/linux-2.6.36/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/exportfs.h>
  12 #include "efs.h"
  13
  14
  15 static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
  16         struct buffer_head *bh;
  17
  18         int                     slot, namelen;
  19         char                    *nameptr;
  20         struct efs_dir          *dirblock;
  21         struct efs_dentry       *dirslot;
  22         efs_ino_t               inodenum;
  23         efs_block_t             block;
  24
  25         if (inode->i_size & (EFS_DIRBSIZE-1))
  26                 printk(KERN_WARNING "EFS: WARNING: find_entry(): directory size not a multiple of EFS_DIRBSIZE\n");
  27
  28         for(block = 0; block < inode->i_blocks; block++) {
  29
  30                 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
  31                 if (!bh) {
  32                         printk(KERN_ERR "EFS: find_entry(): failed to read dir block %d\n", block);
  33                         return 0;
  34                 }
  35
  36                 dirblock = (struct efs_dir *) bh->b_data;
  37
  38                 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
  39                         printk(KERN_ERR "EFS: find_entry(): invalid directory block\n");
  40                         brelse(bh);
  41                         return(0);
  42                 }
  43
  44                 for(slot = 0; slot < dirblock->slots; slot++) {
  45                         dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
  46
  47                         namelen  = dirslot->namelen;
  48                         nameptr  = dirslot->name;
  49
  50                         if ((namelen == len) && (!memcmp(name, nameptr, len))) {
  51                                 inodenum = be32_to_cpu(dirslot->inode);
  52                                 brelse(bh);
  53                                 return(inodenum);
  54                         }
  55                 }
  56                 brelse(bh);
  57         }
  58         return(0);
  59 }
  60
  61 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) {
  62         efs_ino_t inodenum;
  63         struct inode * inode = NULL;
  64
  65         inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
  66         if (inodenum) {
  67                 inode = efs_iget(dir->i_sb, inodenum);
  68                 if (IS_ERR(inode))
  69                         return ERR_CAST(inode);
  70         }
  71
  72         return d_splice_alias(inode, dentry);
  73 }
  74
  75 static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
  76                 u32 generation)
  77 {
  78         struct inode *inode;
  79
  80         if (ino == 0)
  81                 return ERR_PTR(-ESTALE);
  82         inode = efs_iget(sb, ino);
  83         if (IS_ERR(inode))
  84                 return ERR_CAST(inode);
  85
  86         if (generation && inode->i_generation != generation) {
  87                 iput(inode);
  88                 return ERR_PTR(-ESTALE);
  89         }
  90
  91         return inode;
  92 }
  93
  94 struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
  95                 int fh_len, int fh_type)
  96 {
  97         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
  98                                     efs_nfs_get_inode);
  99 }
 100
 101 struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
 102                 int fh_len, int fh_type)
 103 {
 104         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 105                                     efs_nfs_get_inode);
 106 }
 107
 108 struct dentry *efs_get_parent(struct dentry *child)
 109 {
 110         struct dentry *parent = ERR_PTR(-ENOENT);
 111         efs_ino_t ino;
 112
 113         ino = efs_find_entry(child->d_inode, "..", 2);
 114         if (ino)
 115                 parent = d_obtain_alias(efs_iget(child->d_inode->i_sb, ino));
 116
 117         return parent;
 118 }