1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/fs.h>
3 #include <linux/qnx4_fs.h>
4
5 #define QNX4_DEBUG 0
6
7 #if QNX4_DEBUG
8 #define QNX4DEBUG(X) printk X
9 #else
10 #define QNX4DEBUG(X) (void) 0
11 #endif
12
13 struct qnx4_sb_info {
14 unsigned int Version; /* may be useful */
15 struct qnx4_inode_entry *BitMap; /* useful */
16 };
17
18 struct qnx4_inode_info {
19 struct qnx4_inode_entry raw;
20 loff_t mmu_private;
21 struct inode vfs_inode;
22 };
23
24 extern struct inode *qnx4_iget(struct super_block *, unsigned long);
25 extern struct dentry *qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
26 extern unsigned long qnx4_count_free_blocks(struct super_block *sb);
27 extern unsigned long qnx4_block_map(struct inode *inode, long iblock);
28
29 extern const struct inode_operations qnx4_dir_inode_operations;
30 extern const struct file_operations qnx4_dir_operations;
31 extern int qnx4_is_free(struct super_block *sb, long block);
32
33 static inline struct qnx4_sb_info *qnx4_sb(struct super_block *sb)
34 {
35 return sb->s_fs_info;
36 }
37
38 static inline struct qnx4_inode_info *qnx4_i(struct inode *inode)
39 {
40 return container_of(inode, struct qnx4_inode_info, vfs_inode);
41 }
42
43 static inline struct qnx4_inode_entry *qnx4_raw_inode(struct inode *inode)
44 {
45 return &qnx4_i(inode)->raw;
46 }
47
48 /*
49 * A qnx4 directory entry is an inode entry or link info
50 * depending on the status field in the last byte. The
51 * first byte is where the name start either way, and a
52 * zero means it's empty.
53 *
54 * Also, due to a bug in gcc, we don't want to use the
55 * real (differently sized) name arrays in the inode and
56 * link entries, but always the 'de_name[]' one in the
57 * fake struct entry.
58 *
59 * See
60 *
61 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6
62 *
63 * for details, but basically gcc will take the size of the
64 * 'name' array from one of the used union entries randomly.
65 *
66 * This use of 'de_name[]' (48 bytes) avoids the false positive
67 * warnings that would happen if gcc decides to use 'inode.di_name'
68 * (16 bytes) even when the pointer and size were to come from
69 * 'link.dl_name' (48 bytes).
70 *
71 * In all cases the actual name pointer itself is the same, it's
72 * only the gcc internal 'what is the size of this field' logic
73 * that can get confused.
74 */
75 union qnx4_directory_entry {
76 struct {
77 const char de_name[48];
78 u8 de_pad[15];
79 u8 de_status;
80 };
81 struct qnx4_inode_entry inode;
82 struct qnx4_link_info link;
83 };
84
85 static inline const char *get_entry_fname(union qnx4_directory_entry *de,
86 int *size)
87 {
88 /* Make sure the status byte is in the same place for all structs. */
89 BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
90 offsetof(struct qnx4_link_info, dl_status));
91 BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
92 offsetof(union qnx4_directory_entry, de_status));
93
94 if (!de->de_name[0])
95 return NULL;
96 if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
97 return NULL;
98 if (!(de->de_status & QNX4_FILE_LINK))
99 *size = sizeof(de->inode.di_fname);
100 else
101 *size = sizeof(de->link.dl_fname);
102
103 *size = strnlen(de->de_name, *size);
104
105 return de->de_name;
106 }
107
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