[PATCH v2] xfs: publish UUID in struct super_block

[Amir Goldstein <amir73il@gmail.com>]

Copy the uuid of the filesystem to struct super_block s_uuid field,
as several other filesystems already do.  Copy regardless of the nouuid
mount option, because other filesystems also do not guaranty uniqueness
of the s_uuid field in super_block struct.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/xfs/xfs_mount.c | 4 ++++
 1 file changed, 4 insertions(+)

Darrick,

Per your request I moved the copy above nouuid check.

Cheers,
Amir.

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 450bde6..4c0d8d7 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -73,6 +73,10 @@ xfs_uuid_mount(
 	uuid_t			*uuid = &mp->m_sb.sb_uuid;
 	int			hole, i;
 
+	/* Publish UUID in struct super_block */
+	BUILD_BUG_ON(sizeof(mp->m_super->s_uuid) != sizeof(uuid_t));
+	memcpy(&mp->m_super->s_uuid, uuid, sizeof(uuid_t));
+
 	if (mp->m_flags & XFS_MOUNT_NOUUID)
 		return 0;
 
-- 
2.7.4