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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
