[PATCH 15/21] xfs: dynamically create the realtime rmapbt inode when attaching rtdev

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

From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

If the administrator asks us to add a realtime volume to an existing
rmap filesystem, we must allocate and attach the rtrmapbt inode to the
system prior to enabling the rt volume.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 fs/xfs/xfs_rtalloc.c |   58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)


diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 0c5fe0c04307..765f648ffe2b 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -22,6 +22,7 @@
 #include "xfs_da_format.h"
 #include "xfs_imeta.h"
 #include "xfs_error.h"
+#include "xfs_rtrmap_btree.h"
 
 /*
  * Read and return the summary information for a given extent size,
@@ -876,6 +877,60 @@ xfs_alloc_rsum_cache(
  * Visible (exported) functions.
  */
 
+
+/* Add a realtime rmap btree inode. */
+STATIC int
+xfs_growfs_rt_rmap(
+	struct xfs_mount	*mp)
+{
+	struct xfs_imeta_end	ic;
+	struct xfs_inode	*ip = NULL;
+	struct xfs_trans	*tp;
+	int			error;
+
+	if (!xfs_sb_version_hasrmapbt(&mp->m_sb) || mp->m_rrmapip != NULL)
+		return 0;
+
+	/* rtrmapbt requires metadir */
+	if (!xfs_sb_version_hasmetadir(&mp->m_sb))
+		return -EINVAL;
+
+	/* Ensure the path to the rtrmapbt inode exists. */
+	error = xfs_imeta_ensure_dirpath(mp, &XFS_IMETA_RTRMAPBT);
+	if (error)
+		return error;
+
+	/* Create the rtrmapbt inode. */
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_imeta_create,
+			xfs_imeta_create_space_res(mp), 0, 0, &tp);
+	if (error)
+		return error;
+
+	error = xfs_rtrmapbt_create(&tp, &ic, &ip);
+	if (error)
+		goto out_cancel;
+
+	error = xfs_trans_commit(tp);
+	xfs_finish_inode_setup(ip);
+	xfs_imeta_end_update(mp, &ic, error);
+	if (error) {
+		xfs_irele(ip);
+		return error;
+	}
+
+	mp->m_rrmapip = ip;
+	return 0;
+
+out_cancel:
+	xfs_trans_cancel(tp);
+	xfs_imeta_end_update(mp, &ic, error);
+	if (ip) {
+		xfs_finish_inode_setup(ip);
+		xfs_irele(ip);
+	}
+	return error;
+}
+
 /*
  * Grow the realtime area of the filesystem.
  */
@@ -955,6 +1010,9 @@ xfs_growfs_rt(
 	if (error)
 		return error;
 	error = xfs_growfs_rt_alloc(mp, rsumblocks, nrsumblocks, mp->m_rsumip);
+	if (error)
+		return error;
+	error = xfs_growfs_rt_rmap(mp);
 	if (error)
 		return error;