1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_FS_TYPES_H
3#define _LINUX_FS_TYPES_H
4
5/*
6 * This is a header for the common implementation of dirent
7 * to fs on-disk file type conversion. Although the fs on-disk
8 * bits are specific to every file system, in practice, many
9 * file systems use the exact same on-disk format to describe
10 * the lower 3 file type bits that represent the 7 POSIX file
11 * types.
12 *
13 * It is important to note that the definitions in this
14 * header MUST NOT change. This would break both the
15 * userspace ABI and the on-disk format of filesystems
16 * using this code.
17 *
18 * All those file systems can use this generic code for the
19 * conversions.
20 */
21
22/*
23 * struct dirent file types
24 * exposed to user via getdents(2), readdir(3)
25 *
26 * These match bits 12..15 of stat.st_mode
27 * (ie "(i_mode >> 12) & 15").
28 */
29#define S_DT_SHIFT 12
30#define S_DT(mode) (((mode) & S_IFMT) >> S_DT_SHIFT)
31#define S_DT_MASK (S_IFMT >> S_DT_SHIFT)
32
33/* these are defined by POSIX and also present in glibc's dirent.h */
34#define DT_UNKNOWN 0
35#define DT_FIFO 1
36#define DT_CHR 2
37#define DT_DIR 4
38#define DT_BLK 6
39#define DT_REG 8
40#define DT_LNK 10
41#define DT_SOCK 12
42#define DT_WHT 14
43
44#define DT_MAX (S_DT_MASK + 1) /* 16 */
45
46/*
47 * fs on-disk file types.
48 * Only the low 3 bits are used for the POSIX file types.
49 * Other bits are reserved for fs private use.
50 * These definitions are shared and used by multiple filesystems,
51 * and MUST NOT change under any circumstances.
52 *
53 * Note that no fs currently stores the whiteout type on-disk,
54 * so whiteout dirents are exposed to user as DT_CHR.
55 */
56#define FT_UNKNOWN 0
57#define FT_REG_FILE 1
58#define FT_DIR 2
59#define FT_CHRDEV 3
60#define FT_BLKDEV 4
61#define FT_FIFO 5
62#define FT_SOCK 6
63#define FT_SYMLINK 7
64
65#define FT_MAX 8
66
67/*
68 * declarations for helper functions, accompanying implementation
69 * is in fs/fs_types.c
70 */
71extern unsigned char fs_ftype_to_dtype(unsigned int filetype);
72extern unsigned char fs_umode_to_ftype(umode_t mode);
73extern unsigned char fs_umode_to_dtype(umode_t mode);
74
75#endif
76