root/fs/efs/namei.c

DEFINITIONS

1. efs_find_entry
2. efs_lookup
3. efs_nfs_get_inode
4. efs_fh_to_dentry
5. efs_fh_to_parent
6. efs_get_parent

/*
 * 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/smp_lock.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, struct nameidata *nd) {
        efs_ino_t inodenum;
        struct inode * inode = NULL;

        lock_kernel();
        inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
        if (inodenum) {
                inode = efs_iget(dir->i_sb, inodenum);
                if (IS_ERR(inode)) {
                        unlock_kernel();
                        return ERR_CAST(inode);
                }
        }
        unlock_kernel();

        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;
        struct inode *inode;
        efs_ino_t ino;
        long error;

        lock_kernel();

        error = -ENOENT;
        ino = efs_find_entry(child->d_inode, "..", 2);
        if (!ino)
                goto fail;

        inode = efs_iget(child->d_inode->i_sb, ino);
        if (IS_ERR(inode)) {
                error = PTR_ERR(inode);
                goto fail;
        }

        error = -ENOMEM;
        parent = d_alloc_anon(inode);
        if (!parent)
                goto fail_iput;

        unlock_kernel();
        return parent;

 fail_iput:
        iput(inode);
 fail:
        unlock_kernel();
        return ERR_PTR(error);
}