xfs: add a define for statfs magic to uapi

Needed by userspace programs that call fstatfs().

It'd be natural to publish XFS_SB_MAGIC in uapi, but while these two
have identical values, they have different semantic meaning: one is
an enum cookie meant for statfs, the other a signature of the
on-disk format.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

2 files changed, 4 insertions, 2 deletions

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 99250bcb65a7..d3e6cd063688 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -43,6 +43,7 @@
 #include <linux/dax.h>
 #include <linux/init.h>
 #include <linux/slab.h>
+#include <linux/magic.h>
 #include <linux/mount.h>
 #include <linux/mempool.h>
 #include <linux/writeback.h>
@@ -1128,7 +1129,7 @@ xfs_fs_statfs(
         xfs_extlen_t            lsize;
         int64_t                 ffree;
 
-        statp->f_type = XFS_SB_MAGIC;
+        statp->f_type = XFS_SUPER_MAGIC;
         statp->f_namelen = MAXNAMELEN - 1;
 
         id = huge_encode_dev(mp->m_ddev_targp->bt_dev);
@@ -1681,7 +1682,7 @@ xfs_fs_fill_super(
          * we must configure the block size in the superblock before we run the
          * full mount process as the mount process can lookup and cache inodes.
          */
-        sb->s_magic = XFS_SB_MAGIC;
+        sb->s_magic = XFS_SUPER_MAGIC;
         sb->s_blocksize = mp->m_sb.sb_blocksize;
         sb->s_blocksize_bits = ffs(sb->s_blocksize) - 1;
         sb->s_maxbytes = xfs_max_file_offset(sb->s_blocksize_bits);
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 1a6fee974116..96c24478d8ce 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -29,6 +29,7 @@
 #define HPFS_SUPER_MAGIC        0xf995e849
 #define ISOFS_SUPER_MAGIC       0x9660
 #define JFFS2_SUPER_MAGIC       0x72b6
+#define XFS_SUPER_MAGIC         0x58465342      /* "XFSB" */
 #define PSTOREFS_MAGIC          0x6165676C
 #define EFIVARFS_MAGIC          0xde5e81e4
 #define HOSTFS_SUPER_MAGIC      0x00c0ffee