[PATCH v8 24/28] xfs: Add the parent pointer support to the superblock version 5.

[Allison Henderson <allison.henderson@xxxxxxxxxx>]

[dchinner: forward ported and cleaned up]
[achender: rebased and added parent pointer attribute to
           compatible attributes mask]

Signed-off-by: Mark Tinguely <tinguely@xxxxxxx>
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_format.h | 7 +++++--
 fs/xfs/libxfs/xfs_fs.h     | 1 +
 fs/xfs/libxfs/xfs_sb.c     | 2 ++
 fs/xfs/xfs_super.c         | 4 ++++
 4 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 386d734..d77683e 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -453,10 +453,12 @@ xfs_sb_has_compat_feature(
 #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
 #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)		/* reverse map btree */
 #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)		/* reflinked files */
+#define XFS_SB_FEAT_RO_COMPAT_PARENT	(1 << 3)		/* parent inode ptr */
 #define XFS_SB_FEAT_RO_COMPAT_ALL \
 		(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
 		 XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
-		 XFS_SB_FEAT_RO_COMPAT_REFLINK)
+		 XFS_SB_FEAT_RO_COMPAT_REFLINK| \
+		 XFS_SB_FEAT_RO_COMPAT_PARENT)
 #define XFS_SB_FEAT_RO_COMPAT_UNKNOWN	~XFS_SB_FEAT_RO_COMPAT_ALL
 static inline bool
 xfs_sb_has_ro_compat_feature(
@@ -552,7 +554,8 @@ static inline bool xfs_sb_version_hasreflink(struct xfs_sb *sbp)
 
 static inline bool xfs_sb_version_hasparent(struct xfs_sb *sbp)
 {
-	return false; /* We'll enable this at the end of the set */
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
+		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_PARENT));
 }
 
 /*
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index f3aa593..9c58a78 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -210,6 +210,7 @@ typedef struct xfs_fsop_resblks {
 #define XFS_FSOP_GEOM_FLAGS_SPINODES	0x40000	/* sparse inode chunks	*/
 #define XFS_FSOP_GEOM_FLAGS_RMAPBT	0x80000	/* reverse mapping btree */
 #define XFS_FSOP_GEOM_FLAGS_REFLINK	0x100000 /* files can share blocks */
+#define XFS_FSOP_GEOM_FLAGS_PARENT	0x200000 /* parent pointers */
 
 /*
  * Minimum and maximum sizes need for growth checks.
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 081f46e..05dd226 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -1148,6 +1148,8 @@ xfs_fs_geometry(
 		geo->flags |= XFS_FSOP_GEOM_FLAGS_RMAPBT;
 	if (xfs_sb_version_hasreflink(sbp))
 		geo->flags |= XFS_FSOP_GEOM_FLAGS_REFLINK;
+	if(xfs_sb_version_hasparent(sbp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_PARENT;
 	if (xfs_sb_version_hassector(sbp))
 		geo->logsectsize = sbp->sb_logsectsize;
 	else
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 41f53d7..0d6432b 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1710,6 +1710,10 @@ xfs_fs_fill_super(
 		goto out_filestream_unmount;
 	}
 
+	if (xfs_sb_version_hasparent(&mp->m_sb))
+		xfs_alert(mp,
+	"EXPERIMENTAL parent pointer feature enabled. Use at your own risk!");
+
 	error = xfs_mountfs(mp);
 	if (error)
 		goto out_filestream_unmount;
-- 
2.7.4