1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * QNX4 file system, Linux implementation.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Version : 0.2.1
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Using parts of the xiafs filesystem.
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun * History :
10*4882a593Smuzhiyun *
11*4882a593Smuzhiyun * 01-06-1998 by Richard Frowijn : first release.
12*4882a593Smuzhiyun * 21-06-1998 by Frank Denis : dcache support, fixed error codes.
13*4882a593Smuzhiyun * 04-07-1998 by Frank Denis : first step for rmdir/unlink.
14*4882a593Smuzhiyun */
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include <linux/buffer_head.h>
17*4882a593Smuzhiyun #include "qnx4.h"
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun /*
21*4882a593Smuzhiyun * check if the filename is correct. For some obscure reason, qnx writes a
22*4882a593Smuzhiyun * new file twice in the directory entry, first with all possible options at 0
23*4882a593Smuzhiyun * and for a second time the way it is, they want us not to access the qnx
24*4882a593Smuzhiyun * filesystem when whe are using linux.
25*4882a593Smuzhiyun */
qnx4_match(int len,const char * name,struct buffer_head * bh,unsigned long * offset)26*4882a593Smuzhiyun static int qnx4_match(int len, const char *name,
27*4882a593Smuzhiyun struct buffer_head *bh, unsigned long *offset)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun struct qnx4_inode_entry *de;
30*4882a593Smuzhiyun int namelen, thislen;
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun if (bh == NULL) {
33*4882a593Smuzhiyun printk(KERN_WARNING "qnx4: matching unassigned buffer !\n");
34*4882a593Smuzhiyun return 0;
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
37*4882a593Smuzhiyun *offset += QNX4_DIR_ENTRY_SIZE;
38*4882a593Smuzhiyun if ((de->di_status & QNX4_FILE_LINK) != 0) {
39*4882a593Smuzhiyun namelen = QNX4_NAME_MAX;
40*4882a593Smuzhiyun } else {
41*4882a593Smuzhiyun namelen = QNX4_SHORT_NAME_MAX;
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun thislen = strlen( de->di_fname );
44*4882a593Smuzhiyun if ( thislen > namelen )
45*4882a593Smuzhiyun thislen = namelen;
46*4882a593Smuzhiyun if (len != thislen) {
47*4882a593Smuzhiyun return 0;
48*4882a593Smuzhiyun }
49*4882a593Smuzhiyun if (strncmp(name, de->di_fname, len) == 0) {
50*4882a593Smuzhiyun if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {
51*4882a593Smuzhiyun return 1;
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun return 0;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun
qnx4_find_entry(int len,struct inode * dir,const char * name,struct qnx4_inode_entry ** res_dir,int * ino)57*4882a593Smuzhiyun static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
58*4882a593Smuzhiyun const char *name, struct qnx4_inode_entry **res_dir, int *ino)
59*4882a593Smuzhiyun {
60*4882a593Smuzhiyun unsigned long block, offset, blkofs;
61*4882a593Smuzhiyun struct buffer_head *bh;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun *res_dir = NULL;
64*4882a593Smuzhiyun bh = NULL;
65*4882a593Smuzhiyun block = offset = blkofs = 0;
66*4882a593Smuzhiyun while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
67*4882a593Smuzhiyun if (!bh) {
68*4882a593Smuzhiyun block = qnx4_block_map(dir, blkofs);
69*4882a593Smuzhiyun if (block)
70*4882a593Smuzhiyun bh = sb_bread(dir->i_sb, block);
71*4882a593Smuzhiyun if (!bh) {
72*4882a593Smuzhiyun blkofs++;
73*4882a593Smuzhiyun continue;
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
77*4882a593Smuzhiyun if (qnx4_match(len, name, bh, &offset)) {
78*4882a593Smuzhiyun *ino = block * QNX4_INODES_PER_BLOCK +
79*4882a593Smuzhiyun (offset / QNX4_DIR_ENTRY_SIZE) - 1;
80*4882a593Smuzhiyun return bh;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun if (offset < bh->b_size) {
83*4882a593Smuzhiyun continue;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun brelse(bh);
86*4882a593Smuzhiyun bh = NULL;
87*4882a593Smuzhiyun offset = 0;
88*4882a593Smuzhiyun blkofs++;
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun brelse(bh);
91*4882a593Smuzhiyun *res_dir = NULL;
92*4882a593Smuzhiyun return NULL;
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun
qnx4_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)95*4882a593Smuzhiyun struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
96*4882a593Smuzhiyun {
97*4882a593Smuzhiyun int ino;
98*4882a593Smuzhiyun struct qnx4_inode_entry *de;
99*4882a593Smuzhiyun struct qnx4_link_info *lnk;
100*4882a593Smuzhiyun struct buffer_head *bh;
101*4882a593Smuzhiyun const char *name = dentry->d_name.name;
102*4882a593Smuzhiyun int len = dentry->d_name.len;
103*4882a593Smuzhiyun struct inode *foundinode = NULL;
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
106*4882a593Smuzhiyun goto out;
107*4882a593Smuzhiyun /* The entry is linked, let's get the real info */
108*4882a593Smuzhiyun if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
109*4882a593Smuzhiyun lnk = (struct qnx4_link_info *) de;
110*4882a593Smuzhiyun ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) *
111*4882a593Smuzhiyun QNX4_INODES_PER_BLOCK +
112*4882a593Smuzhiyun lnk->dl_inode_ndx;
113*4882a593Smuzhiyun }
114*4882a593Smuzhiyun brelse(bh);
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun foundinode = qnx4_iget(dir->i_sb, ino);
117*4882a593Smuzhiyun if (IS_ERR(foundinode))
118*4882a593Smuzhiyun QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n",
119*4882a593Smuzhiyun PTR_ERR(foundinode)));
120*4882a593Smuzhiyun out:
121*4882a593Smuzhiyun return d_splice_alias(foundinode, dentry);
122*4882a593Smuzhiyun }
123