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
15static 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
64struct 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
76static 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
95struct 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
102struct 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
109struct 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(d_inode(child)->i_sb, ino));
117
118	return parent;
119}
120