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, 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
  73 static 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
  92 struct 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
  99 struct 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
 106 struct 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 }