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	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
61struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) {
62	efs_ino_t inodenum;
63	struct inode * inode = NULL;
64
65	inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
66	if (inodenum) {
67		inode = efs_iget(dir->i_sb, inodenum);
68		if (IS_ERR(inode))
69			return ERR_CAST(inode);
70	}
71
72	return d_splice_alias(inode, dentry);
73}
74
75static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
76		u32 generation)
77{
78	struct inode *inode;
79
80	if (ino == 0)
81		return ERR_PTR(-ESTALE);
82	inode = efs_iget(sb, ino);
83	if (IS_ERR(inode))
84		return ERR_CAST(inode);
85
86	if (generation && inode->i_generation != generation) {
87		iput(inode);
88		return ERR_PTR(-ESTALE);
89	}
90
91	return inode;
92}
93
94struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
95		int fh_len, int fh_type)
96{
97	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
98				    efs_nfs_get_inode);
99}
100
101struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
102		int fh_len, int fh_type)
103{
104	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
105				    efs_nfs_get_inode);
106}
107
108struct dentry *efs_get_parent(struct dentry *child)
109{
110	struct dentry *parent = ERR_PTR(-ENOENT);
111	efs_ino_t ino;
112
113	ino = efs_find_entry(child->d_inode, "..", 2);
114	if (ino)
115		parent = d_obtain_alias(efs_iget(child->d_inode->i_sb, ino));
116
117	return parent;
118}
119