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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * QNX4 file system, Linux implementation. | |
4 | * | |
5 | * Version : 0.2.1 | |
6 | * | |
7 | * Using parts of the xiafs filesystem. | |
8 | * | |
9 | * History : | |
10 | * | |
11 | * 01-06-1998 by Richard Frowijn : first release. | |
12 | * 21-06-1998 by Frank Denis : dcache support, fixed error codes. | |
13 | * 04-07-1998 by Frank Denis : first step for rmdir/unlink. | |
14 | */ | |
15 | ||
1da177e4 | 16 | #include <linux/buffer_head.h> |
964f5369 | 17 | #include "qnx4.h" |
1da177e4 LT |
18 | |
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 | */ | |
26 | static 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) { | |
891ddb95 | 33 | printk(KERN_WARNING "qnx4: matching unassigned buffer !\n"); |
1da177e4 LT |
34 | 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 | } | |
1da177e4 LT |
43 | thislen = strlen( de->di_fname ); |
44 | if ( thislen > namelen ) | |
45 | thislen = namelen; | |
46 | if (len != thislen) { | |
47 | return 0; | |
48 | } | |
49 | if (strncmp(name, de->di_fname, len) == 0) { | |
50 | if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) { | |
51 | return 1; | |
52 | } | |
53 | } | |
54 | return 0; | |
55 | } | |
56 | ||
57 | static struct buffer_head *qnx4_find_entry(int len, struct inode *dir, | |
58 | const char *name, struct qnx4_inode_entry **res_dir, int *ino) | |
59 | { | |
60 | unsigned long block, offset, blkofs; | |
61 | struct buffer_head *bh; | |
62 | ||
63 | *res_dir = NULL; | |
1da177e4 LT |
64 | bh = NULL; |
65 | block = offset = blkofs = 0; | |
66 | while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) { | |
67 | if (!bh) { | |
8f82ecae AV |
68 | block = qnx4_block_map(dir, blkofs); |
69 | if (block) | |
70 | bh = sb_bread(dir->i_sb, block); | |
1da177e4 LT |
71 | if (!bh) { |
72 | blkofs++; | |
73 | continue; | |
74 | } | |
75 | } | |
76 | *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset); | |
77 | if (qnx4_match(len, name, bh, &offset)) { | |
1da177e4 LT |
78 | *ino = block * QNX4_INODES_PER_BLOCK + |
79 | (offset / QNX4_DIR_ENTRY_SIZE) - 1; | |
80 | return bh; | |
81 | } | |
82 | if (offset < bh->b_size) { | |
83 | continue; | |
84 | } | |
85 | brelse(bh); | |
86 | bh = NULL; | |
87 | offset = 0; | |
88 | blkofs++; | |
89 | } | |
90 | brelse(bh); | |
91 | *res_dir = NULL; | |
92 | return NULL; | |
93 | } | |
94 | ||
00cd8dd3 | 95 | struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 LT |
96 | { |
97 | int ino; | |
98 | struct qnx4_inode_entry *de; | |
99 | struct qnx4_link_info *lnk; | |
100 | struct buffer_head *bh; | |
101 | const char *name = dentry->d_name.name; | |
102 | int len = dentry->d_name.len; | |
103 | struct inode *foundinode = NULL; | |
104 | ||
1da177e4 LT |
105 | if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino))) |
106 | goto out; | |
107 | /* The entry is linked, let's get the real info */ | |
108 | if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) { | |
109 | lnk = (struct qnx4_link_info *) de; | |
110 | ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) * | |
111 | QNX4_INODES_PER_BLOCK + | |
112 | lnk->dl_inode_ndx; | |
113 | } | |
114 | brelse(bh); | |
115 | ||
2b7e5bcb | 116 | foundinode = qnx4_iget(dir->i_sb, ino); |
b135dcea | 117 | if (IS_ERR(foundinode)) |
891ddb95 | 118 | QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n", |
2b7e5bcb | 119 | PTR_ERR(foundinode))); |
1da177e4 | 120 | out: |
b135dcea | 121 | return d_splice_alias(foundinode, dentry); |
1da177e4 | 122 | } |