linux/fs/efs/namei.c
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   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
  15static 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
  61struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  62{
  63        efs_ino_t inodenum;
  64        struct inode *inode = NULL;
  65
  66        inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
  67        if (inodenum)
  68                inode = efs_iget(dir->i_sb, inodenum);
  69
  70        return d_splice_alias(inode, dentry);
  71}
  72
  73static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
  74                u32 generation)
  75{
  76        struct inode *inode;
  77
  78        if (ino == 0)
  79                return ERR_PTR(-ESTALE);
  80        inode = efs_iget(sb, ino);
  81        if (IS_ERR(inode))
  82                return ERR_CAST(inode);
  83
  84        if (generation && inode->i_generation != generation) {
  85                iput(inode);
  86                return ERR_PTR(-ESTALE);
  87        }
  88
  89        return inode;
  90}
  91
  92struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
  93                int fh_len, int fh_type)
  94{
  95        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
  96                                    efs_nfs_get_inode);
  97}
  98
  99struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
 100                int fh_len, int fh_type)
 101{
 102        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 103                                    efs_nfs_get_inode);
 104}
 105
 106struct dentry *efs_get_parent(struct dentry *child)
 107{
 108        struct dentry *parent = ERR_PTR(-ENOENT);
 109        efs_ino_t ino;
 110
 111        ino = efs_find_entry(child->d_inode, "..", 2);
 112        if (ino)
 113                parent = d_obtain_alias(efs_iget(child->d_inode->i_sb, ino));
 114
 115        return parent;
 116}
 117
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