[PATCH 24/24] 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/libxfs/xfs_sb.c     |   10 ++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)


diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index ec14477..c289c2e 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -449,7 +449,8 @@ 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/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index a7dcbe0..f74287e 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -219,6 +219,16 @@ xfs_mount_validate_sb(
 "EXPERIMENTAL reverse mapping btree feature enabled. Use at your own risk!");
 	}
 
+	if (xfs_sb_version_hasreflink(sbp)) {
+		xfs_alert(mp,
+"EXPERIMENTAL reflink feature enabled. Use at your own risk!");
+		if (xfs_sb_version_hasrmapbt(sbp)) {
+			printk(KERN_ERR
+"EXPERIMENTAL reverse mapping btree conflicts with reflink!  Mount fails.");
+			return -EINVAL;
+		}
+	}
+
 	/*
 	 * More sanity checking.  Most of these were stolen directly from
 	 * xfs_repair.