[PATCH] ntfs(3): export super block magic

[David Timber <dxdt@dev.snart.me>]

Export NTFS_SUPER_MAGIC and NTFS3_SUPER_MAGIC so that the NTFS
implementation could be differentiated from userspace through
fstatfs() and the coreutils comamnd `stat -f`.

Signed-off-by: David Timber <dxdt@dev.snart.me>
---
 fs/ntfs/ntfs.h             | 1 -
 fs/ntfs/super.c            | 4 ++--
 fs/ntfs3/super.c           | 4 ++--
 include/uapi/linux/magic.h | 2 ++
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/ntfs/ntfs.h b/fs/ntfs/ntfs.h
index 45064dbcc2e4..c41be5fbff17 100644
--- a/fs/ntfs/ntfs.h
+++ b/fs/ntfs/ntfs.h
@@ -76,7 +76,6 @@
 enum {
 	NTFS_BLOCK_SIZE		= 512,
 	NTFS_BLOCK_SIZE_BITS	= 9,
-	NTFS_SB_MAGIC		= 0x5346544e,	/* 'NTFS' */
 	NTFS_MAX_NAME_LEN	= 255,
 	NTFS_MAX_LABEL_LEN	= 128,
 };
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 39a5c3b81001..e595a34619fa 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -2149,7 +2149,7 @@ static int ntfs_statfs(struct dentry *dentry, struct kstatfs *sfs)
 
 	ntfs_debug("Entering.");
 	/* Type of filesystem. */
-	sfs->f_type   = NTFS_SB_MAGIC;
+	sfs->f_type   = NTFS_SUPER_MAGIC;
 	/* Optimal transfer block size. */
 	sfs->f_bsize = vol->cluster_size;
 	/* Fundamental file system block size, used as the unit. */
@@ -2352,7 +2352,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	/* Initialize the cluster and mft allocators. */
 	ntfs_setup_allocators(vol);
 	/* Setup remaining fields in the super block. */
-	sb->s_magic = NTFS_SB_MAGIC;
+	sb->s_magic = NTFS_SUPER_MAGIC;
 	/*
 	 * Ntfs allows 63 bits for the file size, i.e. correct would be:
 	 *	sb->s_maxbytes = ~0ULL >> 1;
diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index 47c11547c972..388d4c51f24b 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -731,7 +731,7 @@ static int ntfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	struct wnd_bitmap *wnd = &sbi->used.bitmap;
 	CLST da_clusters = ntfs_get_da(sbi);
 
-	buf->f_type = sb->s_magic;
+	buf->f_type = NTFS3_SUPER_MAGIC;
 	buf->f_bsize = buf->f_frsize = sbi->cluster_size;
 	buf->f_blocks = wnd->nbits;
 
@@ -1279,7 +1279,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	}
 	sbi->options = options;
 	sb->s_flags |= SB_NODIRATIME;
-	sb->s_magic = 0x7366746e; // "ntfs"
+	sb->s_magic = NTFS3_SUPER_MAGIC;
 	sb->s_op = &ntfs_sops;
 	sb->s_export_op = &ntfs_export_ops;
 	sb->s_time_gran = NTFS_TIME_GRAN; // 100 nsec
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 4f2da935a76c..7bc8058c7108 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -54,6 +54,8 @@
 #define QNX4_SUPER_MAGIC	0x002f		/* qnx4 fs detection */
 #define QNX6_SUPER_MAGIC	0x68191122	/* qnx6 fs detection */
 #define AFS_FS_MAGIC		0x6B414653
+#define NTFS_SUPER_MAGIC	0x5346544e	/* "NTFS" */
+#define NTFS3_SUPER_MAGIC	0x7366746e	/* "ntfs" */
 
 
 #define REISERFS_SUPER_MAGIC	0x52654973	/* used by gcc */
-- 
2.53.0.1.ga224b40d3f.dirty