namei.c

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/*
 * namei.c
 *
 * Copyright (c) 1999 Al Smith
 *
 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
 */

#include <linux/buffer_head.h>
#include <linux/string.h>
#include <linux/exportfs.h>
#include "efs.h"


static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
    struct buffer_head *bh;

    int         slot, namelen;
    char            *nameptr;
    struct efs_dir      *dirblock;
    struct efs_dentry   *dirslot;
    efs_ino_t       inodenum;
    efs_block_t     block;
 
    if (inode->i_size & (EFS_DIRBSIZE-1))
        printk(KERN_WARNING "EFS: WARNING: find_entry(): directory size not a multiple of EFS_DIRBSIZE\n");

    for(block = 0; block < inode->i_blocks; block++) {

        bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
        if (!bh) {
            printk(KERN_ERR "EFS: find_entry(): failed to read dir block %d\n", block);
            return 0;
        }
    
        dirblock = (struct efs_dir *) bh->b_data;

        if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
            printk(KERN_ERR "EFS: find_entry(): invalid directory block\n");
            brelse(bh);
            return(0);
        }

        for(slot = 0; slot < dirblock->slots; slot++) {
            dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));

            namelen  = dirslot->namelen;
            nameptr  = dirslot->name;

            if ((namelen == len) && (!memcmp(name, nameptr, len))) {
                inodenum = be32_to_cpu(dirslot->inode);
                brelse(bh);
                return(inodenum);
            }
        }
        brelse(bh);
    }
    return(0);
}

struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
    efs_ino_t inodenum;
    struct inode *inode = NULL;

    inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
    if (inodenum)
        inode = efs_iget(dir->i_sb, inodenum);

    return d_splice_alias(inode, dentry);
}

static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
        u32 generation)
{
    struct inode *inode;

    if (ino == 0)
        return ERR_PTR(-ESTALE);
    inode = efs_iget(sb, ino);
    if (IS_ERR(inode))
        return ERR_CAST(inode);

    if (generation && inode->i_generation != generation) {
        iput(inode);
        return ERR_PTR(-ESTALE);
    }

    return inode;
}

struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
        int fh_len, int fh_type)
{
    return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
                    efs_nfs_get_inode);
}

struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
        int fh_len, int fh_type)
{
    return generic_fh_to_parent(sb, fid, fh_len, fh_type,
                    efs_nfs_get_inode);
}

struct dentry *efs_get_parent(struct dentry *child)
{
    struct dentry *parent = ERR_PTR(-ENOENT);
    efs_ino_t ino;

    ino = efs_find_entry(child->d_inode, "..", 2);
    if (ino)
        parent = d_obtain_alias(efs_iget(child->d_inode->i_sb, ino));

    return parent;
}