1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * namei.c
4 *
5 * Copyright (c) 1999 Al Smith
6 *
7 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
8 */
9
10 #include <linux/buffer_head.h>
11 #include <linux/string.h>
12 #include <linux/exportfs.h>
13 #include "efs.h"
14
15
16 static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len)
17 {
18 struct buffer_head *bh;
19
20 int slot, namelen;
21 char *nameptr;
22 struct efs_dir *dirblock;
23 struct efs_dentry *dirslot;
24 efs_ino_t inodenum;
25 efs_block_t block;
26
27 if (inode->i_size & (EFS_DIRBSIZE-1))
28 pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
29 __func__);
30
31 for(block = 0; block < inode->i_blocks; block++) {
32
33 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
34 if (!bh) {
35 pr_err("%s(): failed to read dir block %d\n",
36 __func__, block);
37 return 0;
38 }
39
40 dirblock = (struct efs_dir *) bh->b_data;
41
42 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
43 pr_err("%s(): invalid directory block\n", __func__);
44 brelse(bh);
45 return 0;
46 }
47
48 for (slot = 0; slot < dirblock->slots; slot++) {
49 dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
50
51 namelen = dirslot->namelen;
52 nameptr = dirslot->name;
53
54 if ((namelen == len) && (!memcmp(name, nameptr, len))) {
55 inodenum = be32_to_cpu(dirslot->inode);
56 brelse(bh);
57 return inodenum;
58 }
59 }
60 brelse(bh);
61 }
62 return 0;
63 }
64
65 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
66 {
67 efs_ino_t inodenum;
68 struct inode *inode = NULL;
69
70 inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
71 if (inodenum)
72 inode = efs_iget(dir->i_sb, inodenum);
73
74 return d_splice_alias(inode, dentry);
75 }
76
77 static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
78 u32 generation)
79 {
80 struct inode *inode;
81
82 if (ino == 0)
83 return ERR_PTR(-ESTALE);
84 inode = efs_iget(sb, ino);
85 if (IS_ERR(inode))
86 return ERR_CAST(inode);
87
88 if (generation && inode->i_generation != generation) {
89 iput(inode);
90 return ERR_PTR(-ESTALE);
91 }
92
93 return inode;
94 }
95
96 struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
97 int fh_len, int fh_type)
98 {
99 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
100 efs_nfs_get_inode);
101 }
102
103 struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
104 int fh_len, int fh_type)
105 {
106 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
107 efs_nfs_get_inode);
108 }
109
110 struct dentry *efs_get_parent(struct dentry *child)
111 {
112 struct dentry *parent = ERR_PTR(-ENOENT);
113 efs_ino_t ino;
114
115 ino = efs_find_entry(d_inode(child), "..", 2);
116 if (ino)
117 parent = d_obtain_alias(efs_iget(child->d_sb, ino));
118
119 return parent;
120 }
121
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