Merge tag 'dtype_for_v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull dtype handling cleanups from Jan Kara:
 "A reworked dtype cleanup patches based on your feedback to the
  previous version of these.

  Again the series includes only the generic code and ext2 cleanup as a
  sample. The plan is to push cleanups for other filesystems separately
  through respective trees once the generic code lands to reduce the
  number of conflicts"

* tag 'dtype_for_v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: use common file type conversion
  fs: common implementation of file type

2 files changed, 76 insertions, 16 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 08f26046233e..4ede9ffa362a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -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>
@@ -1707,22 +1708,6 @@ int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
 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.
  * This allows the kernel to read directories into kernel space or
diff --git a/include/linux/fs_types.h b/include/linux/fs_types.h
new file mode 100644
index 000000000000..54816791196f
--- /dev/null
+++ b/include/linux/fs_types.h
@@ -0,0 +1,75 @@
+/* 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