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/smp_lock.h>
  12 #include <linux/exportfs.h>
  13 #include "efs.h"
  14
  15
  16 static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
  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                 printk(KERN_WARNING "EFS: WARNING: find_entry(): directory size not a multiple of EFS_DIRBSIZE\n");
  28
  29         for(block = 0; block < inode->i_blocks; block++) {
  30
  31                 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
  32                 if (!bh) {
  33                         printk(KERN_ERR "EFS: find_entry(): failed to read dir block %d\n", block);
  34                         return 0;
  35                 }
  36
  37                 dirblock = (struct efs_dir *) bh->b_data;
  38
  39                 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
  40                         printk(KERN_ERR "EFS: find_entry(): invalid directory block\n");
  41                         brelse(bh);
  42                         return(0);
  43                 }
  44
  45                 for(slot = 0; slot < dirblock->slots; slot++) {
  46                         dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
  47
  48                         namelen  = dirslot->namelen;
  49                         nameptr  = dirslot->name;
  50
  51                         if ((namelen == len) && (!memcmp(name, nameptr, len))) {
  52                                 inodenum = be32_to_cpu(dirslot->inode);
  53                                 brelse(bh);
  54                                 return(inodenum);
  55                         }
  56                 }
  57                 brelse(bh);
  58         }
  59         return(0);
  60 }
  61
  62 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) {
  63         efs_ino_t inodenum;
  64         struct inode * inode = NULL;
  65
  66         lock_kernel();
  67         inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
  68         if (inodenum) {
  69                 inode = efs_iget(dir->i_sb, inodenum);
  70                 if (IS_ERR(inode)) {
  71                         unlock_kernel();
  72                         return ERR_CAST(inode);
  73                 }
  74         }
  75         unlock_kernel();
  76
  77         return d_splice_alias(inode, dentry);
  78 }
  79
  80 static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
  81                 u32 generation)
  82 {
  83         struct inode *inode;
  84
  85         if (ino == 0)
  86                 return ERR_PTR(-ESTALE);
  87         inode = efs_iget(sb, ino);
  88         if (IS_ERR(inode))
  89                 return ERR_CAST(inode);
  90
  91         if (generation && inode->i_generation != generation) {
  92                 iput(inode);
  93                 return ERR_PTR(-ESTALE);
  94         }
  95
  96         return inode;
  97 }
  98
  99 struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
 100                 int fh_len, int fh_type)
 101 {
 102         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 103                                     efs_nfs_get_inode);
 104 }
 105
 106 struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
 107                 int fh_len, int fh_type)
 108 {
 109         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 110                                     efs_nfs_get_inode);
 111 }
 112
 113 struct dentry *efs_get_parent(struct dentry *child)
 114 {
 115         struct dentry *parent = ERR_PTR(-ENOENT);
 116         efs_ino_t ino;
 117
 118         lock_kernel();
 119         ino = efs_find_entry(child->d_inode, "..", 2);
 120         if (ino)
 121                 parent = d_obtain_alias(efs_iget(child->d_inode->i_sb, ino));
 122         unlock_kernel();
 123
 124         return parent;
 125 }