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 {
  17         struct buffer_head *bh;
  18
  19         int                     slot, namelen;
  20         char                    *nameptr;
  21         struct efs_dir          *dirblock;
  22         struct efs_dentry       *dirslot;
  23         efs_ino_t               inodenum;
  24         efs_block_t             block;
  25
  26         if (inode->i_size & (EFS_DIRBSIZE-1))
  27                 pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
  28                         __func__);
  29
  30         for(block = 0; block < inode->i_blocks; block++) {
  31
  32                 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
  33                 if (!bh) {
  34                         pr_err("%s(): failed to read dir block %d\n",
  35                                __func__, block);
  36                         return 0;
  37                 }
  38
  39                 dirblock = (struct efs_dir *) bh->b_data;
  40
  41                 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
  42                         pr_err("%s(): invalid directory block\n", __func__);
  43                         brelse(bh);
  44                         return 0;
  45                 }
  46
  47                 for (slot = 0; slot < dirblock->slots; slot++) {
  48                         dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
  49
  50                         namelen  = dirslot->namelen;
  51                         nameptr  = dirslot->name;
  52
  53                         if ((namelen == len) && (!memcmp(name, nameptr, len))) {
  54                                 inodenum = be32_to_cpu(dirslot->inode);
  55                                 brelse(bh);
  56                                 return inodenum;
  57                         }
  58                 }
  59                 brelse(bh);
  60         }
  61         return 0;
  62 }
  63
  64 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  65 {
  66         efs_ino_t inodenum;
  67         struct inode *inode = NULL;
  68
  69         inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
  70         if (inodenum)
  71                 inode = efs_iget(dir->i_sb, inodenum);
  72
  73         return d_splice_alias(inode, dentry);
  74 }
  75
  76 static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
  77                 u32 generation)
  78 {
  79         struct inode *inode;
  80
  81         if (ino == 0)
  82                 return ERR_PTR(-ESTALE);
  83         inode = efs_iget(sb, ino);
  84         if (IS_ERR(inode))
  85                 return ERR_CAST(inode);
  86
  87         if (generation && inode->i_generation != generation) {
  88                 iput(inode);
  89                 return ERR_PTR(-ESTALE);
  90         }
  91
  92         return inode;
  93 }
  94
  95 struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
  96                 int fh_len, int fh_type)
  97 {
  98         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
  99                                     efs_nfs_get_inode);
 100 }
 101
 102 struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
 103                 int fh_len, int fh_type)
 104 {
 105         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 106                                     efs_nfs_get_inode);
 107 }
 108
 109 struct dentry *efs_get_parent(struct dentry *child)
 110 {
 111         struct dentry *parent = ERR_PTR(-ENOENT);
 112         efs_ino_t ino;
 113
 114         ino = efs_find_entry(d_inode(child), "..", 2);
 115         if (ino)
 116                 parent = d_obtain_alias(efs_iget(child->d_sb, ino));
 117
 118         return parent;
 119 }