blob: 58703ebba879e36c35824bc61bbf8669efb7ad32 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * QNX4 file system, Linux implementation.
3 *
4 * Version : 0.2.1
5 *
6 * Using parts of the xiafs filesystem.
7 *
8 * History :
9 *
10 * 01-06-1998 by Richard Frowijn : first release.
11 * 21-06-1998 by Frank Denis : dcache support, fixed error codes.
12 * 04-07-1998 by Frank Denis : first step for rmdir/unlink.
13 */
14
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/smp_lock.h>
16#include <linux/buffer_head.h>
Al Viro964f5362009-06-07 09:47:13 -040017#include "qnx4.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
19
20/*
21 * check if the filename is correct. For some obscure reason, qnx writes a
22 * new file twice in the directory entry, first with all possible options at 0
23 * and for a second time the way it is, they want us not to access the qnx
24 * filesystem when whe are using linux.
25 */
26static int qnx4_match(int len, const char *name,
27 struct buffer_head *bh, unsigned long *offset)
28{
29 struct qnx4_inode_entry *de;
30 int namelen, thislen;
31
32 if (bh == NULL) {
Anders Larsen891ddb92009-09-26 20:15:09 +020033 printk(KERN_WARNING "qnx4: matching unassigned buffer !\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 return 0;
35 }
36 de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
37 *offset += QNX4_DIR_ENTRY_SIZE;
38 if ((de->di_status & QNX4_FILE_LINK) != 0) {
39 namelen = QNX4_NAME_MAX;
40 } else {
41 namelen = QNX4_SHORT_NAME_MAX;
42 }
43 /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
44 if (!len && (de->di_fname[0] == '.') && (de->di_fname[1] == '\0')) {
45 return 1;
46 }
47 thislen = strlen( de->di_fname );
48 if ( thislen > namelen )
49 thislen = namelen;
50 if (len != thislen) {
51 return 0;
52 }
53 if (strncmp(name, de->di_fname, len) == 0) {
54 if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {
55 return 1;
56 }
57 }
58 return 0;
59}
60
61static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
62 const char *name, struct qnx4_inode_entry **res_dir, int *ino)
63{
64 unsigned long block, offset, blkofs;
65 struct buffer_head *bh;
66
67 *res_dir = NULL;
68 if (!dir->i_sb) {
Anders Larsen891ddb92009-09-26 20:15:09 +020069 printk(KERN_WARNING "qnx4: no superblock on dir.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 return NULL;
71 }
72 bh = NULL;
73 block = offset = blkofs = 0;
74 while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
75 if (!bh) {
76 bh = qnx4_bread(dir, blkofs, 0);
77 if (!bh) {
78 blkofs++;
79 continue;
80 }
81 }
82 *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
83 if (qnx4_match(len, name, bh, &offset)) {
84 block = qnx4_block_map( dir, blkofs );
85 *ino = block * QNX4_INODES_PER_BLOCK +
86 (offset / QNX4_DIR_ENTRY_SIZE) - 1;
87 return bh;
88 }
89 if (offset < bh->b_size) {
90 continue;
91 }
92 brelse(bh);
93 bh = NULL;
94 offset = 0;
95 blkofs++;
96 }
97 brelse(bh);
98 *res_dir = NULL;
99 return NULL;
100}
101
102struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
103{
104 int ino;
105 struct qnx4_inode_entry *de;
106 struct qnx4_link_info *lnk;
107 struct buffer_head *bh;
108 const char *name = dentry->d_name.name;
109 int len = dentry->d_name.len;
110 struct inode *foundinode = NULL;
111
112 lock_kernel();
113 if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
114 goto out;
115 /* The entry is linked, let's get the real info */
116 if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
117 lnk = (struct qnx4_link_info *) de;
118 ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) *
119 QNX4_INODES_PER_BLOCK +
120 lnk->dl_inode_ndx;
121 }
122 brelse(bh);
123
David Howells2b7e5bc2008-02-07 00:15:45 -0800124 foundinode = qnx4_iget(dir->i_sb, ino);
125 if (IS_ERR(foundinode)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 unlock_kernel();
Anders Larsen891ddb92009-09-26 20:15:09 +0200127 QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n",
David Howells2b7e5bc2008-02-07 00:15:45 -0800128 PTR_ERR(foundinode)));
129 return ERR_CAST(foundinode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 }
131out:
132 unlock_kernel();
133 d_add(dentry, foundinode);
134
135 return NULL;
136}