[PATCH 68/71] xfs: recognize the reflink feature bit

[Darrick J. Wong]

Add the reflink feature flag to the set of recognized feature flags.
This enables users to write to reflink filesystems.

Signed-off-by: Darrick J. Wong <darrick.wong at oracle.com>
---
 fs/xfs/libxfs/xfs_format.h |    3 ++-
 fs/xfs/xfs_super.c         |    7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)


diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 4f2a354..bf40fa8 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -459,7 +459,8 @@ xfs_sb_has_compat_feature(
 #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)		/* reflinked files */
 #define XFS_SB_FEAT_RO_COMPAT_ALL \
 		(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
-		 XFS_SB_FEAT_RO_COMPAT_RMAPBT)
+		 XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
+		 XFS_SB_FEAT_RO_COMPAT_REFLINK)
 #define XFS_SB_FEAT_RO_COMPAT_UNKNOWN	~XFS_SB_FEAT_RO_COMPAT_ALL
 static inline bool
 xfs_sb_has_ro_compat_feature(
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 6ef6244..2d249a5 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1596,6 +1596,9 @@ xfs_fs_fill_super(
 			"DAX unsupported by block device. Turning off DAX.");
 			mp->m_flags &= ~XFS_MOUNT_DAX;
 		}
+		if (xfs_sb_version_hasreflink(&mp->m_sb))
+			xfs_alert(mp,
+		"DAX and reflink have not been tested together!");
 	}
 
 	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
@@ -1609,6 +1612,10 @@ xfs_fs_fill_super(
 	"EXPERIMENTAL reverse mapping btree feature enabled. Use at your own risk!");
 	}
 
+	if (xfs_sb_version_hasreflink(&mp->m_sb))
+		xfs_alert(mp,
+	"EXPERIMENTAL reflink feature enabled. Use at your own risk!");
+
 	error = xfs_mountfs(mp);
 	if (error)
 		goto out_filestream_unmount;