ovl: move super block magic number to magic.h

The overlayfs file system is not recognized by programs
like tail because the magic number is not in standard header location.

Move it so that the value will propagate on for the GNU library
and utilities. Needs to go in the fstatfs manual page as well.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 97cacb5..32f3124 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -24,8 +24,6 @@ MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
 MODULE_DESCRIPTION("Overlay filesystem");
 MODULE_LICENSE("GPL");
 
-#define OVERLAYFS_SUPER_MAGIC 0x794c7630
-
 struct ovl_config {
        char *lowerdir;
        char *upperdir;

diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 7b1425a..eec4389 100644 (file)
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -31,6 +31,7 @@
 #define PSTOREFS_MAGIC         0x6165676C
 #define EFIVARFS_MAGIC         0xde5e81e4
 #define HOSTFS_SUPER_MAGIC     0x00c0ffee
+#define OVERLAYFS_SUPER_MAGIC  0x794c7630
 
 #define MINIX_SUPER_MAGIC      0x137F          /* minix v1 fs, 14 char names */
 #define MINIX_SUPER_MAGIC2     0x138F          /* minix v1 fs, 30 char names */