[PATCH 13/14] xfs: add reflink btree root when expanding the filesystem

[Darrick J. Wong]

Create the root of the reflink btree whenever we add an AG to the
filesystem.  Plumb in the bits that enable growfs to ask the kernel
whether or not the fs supports reflink.

Signed-off-by: Darrick J. Wong <darrick.wong at oracle.com>
---
 fs/xfs/libxfs/xfs_fs.h     |    1 +
 fs/xfs/libxfs/xfs_shared.h |    1 +
 fs/xfs/xfs_fsops.c         |   30 +++++++++++++++++++++++++++++-
 3 files changed, 31 insertions(+), 1 deletion(-)


diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 6b1b71c..d7541f7 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -242,6 +242,7 @@ typedef struct xfs_fsop_resblks {
 #define XFS_FSOP_GEOM_FLAGS_FINOBT	0x20000	/* free inode btree */
 #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	/* reflink */
 
 /*
  * Minimum and maximum sizes need for growth checks.
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index d1de74e..807c0e3 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -53,6 +53,7 @@ extern const struct xfs_buf_ops xfs_dquot_buf_ops;
 extern const struct xfs_buf_ops xfs_sb_buf_ops;
 extern const struct xfs_buf_ops xfs_sb_quiet_buf_ops;
 extern const struct xfs_buf_ops xfs_symlink_buf_ops;
+extern const struct xfs_buf_ops xfs_reflinkbt_buf_ops;
 
 /*
  * Transaction types.  Used to distinguish types of buffers. These never reach
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 9aabefb..d68a3b5 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -106,7 +106,9 @@ xfs_fs_geometry(
 			(xfs_sb_version_hassparseinodes(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_SPINODES : 0) |
 			(xfs_sb_version_hasrmapbt(&mp->m_sb) ?
-				XFS_FSOP_GEOM_FLAGS_RMAPBT : 0);
+				XFS_FSOP_GEOM_FLAGS_RMAPBT : 0) |
+			(xfs_sb_version_hasreflink(&mp->m_sb) ?
+				XFS_FSOP_GEOM_FLAGS_REFLINK : 0);
 		geo->logsectsize = xfs_sb_version_hassector(&mp->m_sb) ?
 				mp->m_sb.sb_logsectsize : BBSIZE;
 		geo->rtsectsize = mp->m_sb.sb_blocksize;
@@ -260,6 +262,10 @@ xfs_growfs_data_private(
 		agf->agf_longest = cpu_to_be32(tmpsize);
 		if (xfs_sb_version_hascrc(&mp->m_sb))
 			uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_uuid);
+		if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+			agf->agf_reflink_root = cpu_to_be32(XFS_RL_BLOCK(mp));
+			agf->agf_reflink_level = cpu_to_be32(1);
+		}
 
 		error = xfs_bwrite(bp);
 		xfs_buf_relse(bp);
@@ -503,6 +509,28 @@ xfs_growfs_data_private(
 				goto error0;
 		}
 
+		/*
+		 * reflink btree root block
+		 */
+		if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+			bp = xfs_growfs_get_hdr_buf(mp,
+				XFS_AGB_TO_DADDR(mp, agno, XFS_RL_BLOCK(mp)),
+				BTOBB(mp->m_sb.sb_blocksize), 0,
+				&xfs_reflinkbt_buf_ops);
+			if (!bp) {
+				error = -ENOMEM;
+				goto error0;
+			}
+
+			xfs_btree_init_block(mp, bp, XFS_RLBT_CRC_MAGIC,
+					     0, 0, agno,
+					     XFS_BTREE_CRC_BLOCKS);
+
+			error = xfs_bwrite(bp);
+			xfs_buf_relse(bp);
+			if (error)
+				goto error0;
+		}
 	}
 	xfs_trans_agblocks_delta(tp, nfree);
 	/*