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

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 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;