fs: common implementation of file type (bbe7449e) · Commits · 方亚芬 / linux

MAINTAINERS

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		@@ -5881,6 +5881,7 @@ L: linux-fsdevel@vger.kernel.org
		S: Maintained
		F: fs/*
		F: include/linux/fs.h
		F: include/linux/fs_types.h
		F: include/uapi/linux/fs.h

		FINTEK F75375S HARDWARE MONITOR AND FAN CONTROLLER DRIVER

fs/Makefile

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		@@ -12,7 +12,8 @@ obj-y := open.o read_write.o file_table.o super.o \
		attr.o bad_inode.o file.o filesystems.o namespace.o \
		seq_file.o xattr.o libfs.o fs-writeback.o \
		pnode.o splice.o sync.o utimes.o d_path.o \
		stack.o fs_struct.o statfs.o fs_pin.o nsfs.o
		stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
		fs_types.o

		ifeq ($(CONFIG_BLOCK),y)
		obj-y += buffer.o block_dev.o direct-io.o mpage.o

fs/fs_types.c

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		// SPDX-License-Identifier: GPL-2.0
		#include <linux/fs.h>
		#include <linux/export.h>

		/*
		* fs on-disk file type to dirent file type conversion
		*/
		static const unsigned char fs_dtype_by_ftype[FT_MAX] = {
		[FT_UNKNOWN] = DT_UNKNOWN,
		[FT_REG_FILE] = DT_REG,
		[FT_DIR] = DT_DIR,
		[FT_CHRDEV] = DT_CHR,
		[FT_BLKDEV] = DT_BLK,
		[FT_FIFO] = DT_FIFO,
		[FT_SOCK] = DT_SOCK,
		[FT_SYMLINK] = DT_LNK
		};

		/**
		* fs_ftype_to_dtype() - fs on-disk file type to dirent type.
		* @filetype: The on-disk file type to convert.
		*
		* This function converts the on-disk file type value (FT_*) to the directory
		* entry type (DT_*).
		*
		* Context: Any context.
		* Return:
		* * DT_UNKNOWN - Unknown type
		* * DT_FIFO - FIFO
		* * DT_CHR - Character device
		* * DT_DIR - Directory
		* * DT_BLK - Block device
		* * DT_REG - Regular file
		* * DT_LNK - Symbolic link
		* * DT_SOCK - Local-domain socket
		*/
		unsigned char fs_ftype_to_dtype(unsigned int filetype)
		{
		if (filetype >= FT_MAX)
		return DT_UNKNOWN;

		return fs_dtype_by_ftype[filetype];
		}
		EXPORT_SYMBOL_GPL(fs_ftype_to_dtype);

		/*
		* dirent file type to fs on-disk file type conversion
		* Values not initialized explicitly are FT_UNKNOWN (0).
		*/
		static const unsigned char fs_ftype_by_dtype[DT_MAX] = {
		[DT_REG] = FT_REG_FILE,
		[DT_DIR] = FT_DIR,
		[DT_LNK] = FT_SYMLINK,
		[DT_CHR] = FT_CHRDEV,
		[DT_BLK] = FT_BLKDEV,
		[DT_FIFO] = FT_FIFO,
		[DT_SOCK] = FT_SOCK,
		};

		/**
		* fs_umode_to_ftype() - file mode to on-disk file type.
		* @mode: The file mode to convert.
		*
		* This function converts the file mode value to the on-disk file type (FT_*).
		*
		* Context: Any context.
		* Return:
		* * FT_UNKNOWN - Unknown type
		* * FT_REG_FILE - Regular file
		* * FT_DIR - Directory
		* * FT_CHRDEV - Character device
		* * FT_BLKDEV - Block device
		* * FT_FIFO - FIFO
		* * FT_SOCK - Local-domain socket
		* * FT_SYMLINK - Symbolic link
		*/
		unsigned char fs_umode_to_ftype(umode_t mode)
		{
		return fs_ftype_by_dtype[S_DT(mode)];
		}
		EXPORT_SYMBOL_GPL(fs_umode_to_ftype);

		/**
		* fs_umode_to_dtype() - file mode to dirent file type.
		* @mode: The file mode to convert.
		*
		* This function converts the file mode value to the directory
		* entry type (DT_*).
		*
		* Context: Any context.
		* Return:
		* * DT_UNKNOWN - Unknown type
		* * DT_FIFO - FIFO
		* * DT_CHR - Character device
		* * DT_DIR - Directory
		* * DT_BLK - Block device
		* * DT_REG - Regular file
		* * DT_LNK - Symbolic link
		* * DT_SOCK - Local-domain socket
		*/
		unsigned char fs_umode_to_dtype(umode_t mode)
		{
		return fs_ftype_to_dtype(fs_umode_to_ftype(mode));
		}
		EXPORT_SYMBOL_GPL(fs_umode_to_dtype);

include/linux/fs.h

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		@@ -37,6 +37,7 @@
		#include <linux/uuid.h>
		#include <linux/errseq.h>
		#include <linux/ioprio.h>
		#include <linux/fs_types.h>

		#include <asm/byteorder.h>
		#include <uapi/linux/fs.h>
		@@ -1699,22 +1700,6 @@ int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
		u64 phys, u64 len, u32 flags);
		int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);

		/*
		* File types
		*
		* NOTE! These match bits 12..15 of stat.st_mode
		* (ie "(i_mode >> 12) & 15").
		*/
		#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

		/*
		* This is the "filldir" function type, used by readdir() to let
		* the kernel specify what kind of dirent layout it wants to have.

include/linux/fs_types.h

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		/* 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