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authorPhillip Potter <phil@philpotter.co.uk>2019-01-21 00:54:27 +0000
committerJan Kara <jack@suse.cz>2019-01-21 17:48:13 +0100
commitbbe7449e2599b58cf7b995461e2189998111f907 (patch)
tree45fb7c60c894558ebbeda7c2c444447739c8cd02 /fs/fs_types.c
parent49a57857aeea06ca831043acbb0fa5e0f50602fd (diff)
fs: common implementation of file type
Many file systems use a copy&paste implementation of dirent to on-disk file type conversions. Create a common implementation to be used by file systems with some useful conversion helpers to reduce open coded file type conversions in file system code. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Phillip Potter <phil@philpotter.co.uk> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/fs_types.c')
-rw-r--r--fs/fs_types.c105
1 files changed, 105 insertions, 0 deletions
diff --git a/fs/fs_types.c b/fs/fs_types.c
new file mode 100644
index 000000000000..78365e5dc08c
--- /dev/null
+++ b/fs/fs_types.c
@@ -0,0 +1,105 @@
+// 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);