Staging
v0.5.2
v0.5.2
https://github.com/torvalds/linux
Tip revision: 2ccdd1b13c591d306f0401d98dedc4bdcd02b421 authored by Linus Torvalds on 13 August 2023, 18:29:55 UTC
Linux 6.5-rc6
Linux 6.5-rc6
Tip revision: 2ccdd1b
fs_types.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FS_TYPES_H
#define _LINUX_FS_TYPES_H
/*
* This is a header for the common implementation of dirent
* to fs on-disk file type conversion. Although the fs on-disk
* bits are specific to every file system, in practice, many
* file systems use the exact same on-disk format to describe
* the lower 3 file type bits that represent the 7 POSIX file
* types.
*
* It is important to note that the definitions in this
* header MUST NOT change. This would break both the
* userspace ABI and the on-disk format of filesystems
* using this code.
*
* All those file systems can use this generic code for the
* conversions.
*/
/*
* struct dirent file types
* exposed to user via getdents(2), readdir(3)
*
* These match bits 12..15 of stat.st_mode
* (ie "(i_mode >> 12) & 15").
*/
#define S_DT_SHIFT 12
#define S_DT(mode) (((mode) & S_IFMT) >> S_DT_SHIFT)
#define S_DT_MASK (S_IFMT >> S_DT_SHIFT)
/* these are defined by POSIX and also present in glibc's dirent.h */
#define DT_UNKNOWN 0
#define DT_FIFO 1
#define DT_CHR 2
#define DT_DIR 4
#define DT_BLK 6
#define DT_REG 8
#define DT_LNK 10
#define DT_SOCK 12
#define DT_WHT 14
#define DT_MAX (S_DT_MASK + 1) /* 16 */
/*
* fs on-disk file types.
* Only the low 3 bits are used for the POSIX file types.
* Other bits are reserved for fs private use.
* These definitions are shared and used by multiple filesystems,
* and MUST NOT change under any circumstances.
*
* Note that no fs currently stores the whiteout type on-disk,
* so whiteout dirents are exposed to user as DT_CHR.
*/
#define FT_UNKNOWN 0
#define FT_REG_FILE 1
#define FT_DIR 2
#define FT_CHRDEV 3
#define FT_BLKDEV 4
#define FT_FIFO 5
#define FT_SOCK 6
#define FT_SYMLINK 7
#define FT_MAX 8
/*
* declarations for helper functions, accompanying implementation
* is in fs/fs_types.c
*/
extern unsigned char fs_ftype_to_dtype(unsigned int filetype);
extern unsigned char fs_umode_to_ftype(umode_t mode);
extern unsigned char fs_umode_to_dtype(umode_t mode);
#endif