1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * namei.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (c) 1999 Al Smith
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <linux/buffer_head.h>
11*4882a593Smuzhiyun #include <linux/string.h>
12*4882a593Smuzhiyun #include <linux/exportfs.h>
13*4882a593Smuzhiyun #include "efs.h"
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun
efs_find_entry(struct inode * inode,const char * name,int len)16*4882a593Smuzhiyun static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len)
17*4882a593Smuzhiyun {
18*4882a593Smuzhiyun struct buffer_head *bh;
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun int slot, namelen;
21*4882a593Smuzhiyun char *nameptr;
22*4882a593Smuzhiyun struct efs_dir *dirblock;
23*4882a593Smuzhiyun struct efs_dentry *dirslot;
24*4882a593Smuzhiyun efs_ino_t inodenum;
25*4882a593Smuzhiyun efs_block_t block;
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun if (inode->i_size & (EFS_DIRBSIZE-1))
28*4882a593Smuzhiyun pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
29*4882a593Smuzhiyun __func__);
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun for(block = 0; block < inode->i_blocks; block++) {
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
34*4882a593Smuzhiyun if (!bh) {
35*4882a593Smuzhiyun pr_err("%s(): failed to read dir block %d\n",
36*4882a593Smuzhiyun __func__, block);
37*4882a593Smuzhiyun return 0;
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun dirblock = (struct efs_dir *) bh->b_data;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
43*4882a593Smuzhiyun pr_err("%s(): invalid directory block\n", __func__);
44*4882a593Smuzhiyun brelse(bh);
45*4882a593Smuzhiyun return 0;
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun for (slot = 0; slot < dirblock->slots; slot++) {
49*4882a593Smuzhiyun dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun namelen = dirslot->namelen;
52*4882a593Smuzhiyun nameptr = dirslot->name;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun if ((namelen == len) && (!memcmp(name, nameptr, len))) {
55*4882a593Smuzhiyun inodenum = be32_to_cpu(dirslot->inode);
56*4882a593Smuzhiyun brelse(bh);
57*4882a593Smuzhiyun return inodenum;
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun brelse(bh);
61*4882a593Smuzhiyun }
62*4882a593Smuzhiyun return 0;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
efs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)65*4882a593Smuzhiyun struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
66*4882a593Smuzhiyun {
67*4882a593Smuzhiyun efs_ino_t inodenum;
68*4882a593Smuzhiyun struct inode *inode = NULL;
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
71*4882a593Smuzhiyun if (inodenum)
72*4882a593Smuzhiyun inode = efs_iget(dir->i_sb, inodenum);
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun return d_splice_alias(inode, dentry);
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun
efs_nfs_get_inode(struct super_block * sb,u64 ino,u32 generation)77*4882a593Smuzhiyun static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
78*4882a593Smuzhiyun u32 generation)
79*4882a593Smuzhiyun {
80*4882a593Smuzhiyun struct inode *inode;
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun if (ino == 0)
83*4882a593Smuzhiyun return ERR_PTR(-ESTALE);
84*4882a593Smuzhiyun inode = efs_iget(sb, ino);
85*4882a593Smuzhiyun if (IS_ERR(inode))
86*4882a593Smuzhiyun return ERR_CAST(inode);
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun if (generation && inode->i_generation != generation) {
89*4882a593Smuzhiyun iput(inode);
90*4882a593Smuzhiyun return ERR_PTR(-ESTALE);
91*4882a593Smuzhiyun }
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun return inode;
94*4882a593Smuzhiyun }
95*4882a593Smuzhiyun
efs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)96*4882a593Smuzhiyun struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
97*4882a593Smuzhiyun int fh_len, int fh_type)
98*4882a593Smuzhiyun {
99*4882a593Smuzhiyun return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
100*4882a593Smuzhiyun efs_nfs_get_inode);
101*4882a593Smuzhiyun }
102*4882a593Smuzhiyun
efs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)103*4882a593Smuzhiyun struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
104*4882a593Smuzhiyun int fh_len, int fh_type)
105*4882a593Smuzhiyun {
106*4882a593Smuzhiyun return generic_fh_to_parent(sb, fid, fh_len, fh_type,
107*4882a593Smuzhiyun efs_nfs_get_inode);
108*4882a593Smuzhiyun }
109*4882a593Smuzhiyun
efs_get_parent(struct dentry * child)110*4882a593Smuzhiyun struct dentry *efs_get_parent(struct dentry *child)
111*4882a593Smuzhiyun {
112*4882a593Smuzhiyun struct dentry *parent = ERR_PTR(-ENOENT);
113*4882a593Smuzhiyun efs_ino_t ino;
114*4882a593Smuzhiyun
115*4882a593Smuzhiyun ino = efs_find_entry(d_inode(child), "..", 2);
116*4882a593Smuzhiyun if (ino)
117*4882a593Smuzhiyun parent = d_obtain_alias(efs_iget(child->d_sb, ino));
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun return parent;
120*4882a593Smuzhiyun }
121