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(sb: inode->i_sb, block: 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(p: name, q: nameptr, size: 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(inode: dir, name: dentry->d_name.name, len: 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(error: -ESTALE); |
84 | inode = efs_iget(sb, ino); |
85 | if (IS_ERR(ptr: inode)) |
86 | return ERR_CAST(ptr: inode); |
87 | |
88 | if (generation && inode->i_generation != generation) { |
89 | iput(inode); |
90 | return ERR_PTR(error: -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 | get_inode: 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 | get_inode: efs_nfs_get_inode); |
108 | } |
109 | |
110 | struct dentry *efs_get_parent(struct dentry *child) |
111 | { |
112 | struct dentry *parent = ERR_PTR(error: -ENOENT); |
113 | efs_ino_t ino; |
114 | |
115 | ino = efs_find_entry(inode: d_inode(dentry: child), name: ".." , len: 2); |
116 | if (ino) |
117 | parent = d_obtain_alias(efs_iget(child->d_sb, ino)); |
118 | |
119 | return parent; |
120 | } |
121 | |