[PATCH v3 3/4] xfs: hoist out xfs_resizefs_init_new_ags()

[Gao Xiang <hsiangkao@redhat.com>]

Move out related logic for initializing new added AGs to a new helper
in preparation for shrinking. No logic changes.

Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
---
 fs/xfs/xfs_fsops.c | 74 +++++++++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 30 deletions(-)

diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 6c5f6a50da2e..a792d1f0ac55 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -20,6 +20,49 @@
 #include "xfs_ag.h"
 #include "xfs_ag_resv.h"
 
+static int
+xfs_resizefs_init_new_ags(
+	xfs_mount_t		*mp,
+	struct aghdr_init_data	*id,
+	xfs_agnumber_t		oagcount,
+	xfs_agnumber_t		nagcount,
+	xfs_rfsblock_t		*delta)
+{
+	xfs_rfsblock_t		nb = mp->m_sb.sb_dblocks + *delta;
+	int			error;
+
+	/*
+	 * Write new AG headers to disk. Non-transactional, but need to be
+	 * written and completed prior to the growfs transaction being logged.
+	 * To do this, we use a delayed write buffer list and wait for
+	 * submission and IO completion of the list as a whole. This allows the
+	 * IO subsystem to merge all the AG headers in a single AG into a single
+	 * IO and hide most of the latency of the IO from us.
+	 *
+	 * This also means that if we get an error whilst building the buffer
+	 * list to write, we can cancel the entire list without having written
+	 * anything.
+	 */
+	INIT_LIST_HEAD(&id->buffer_list);
+	for (id->agno = nagcount - 1;
+	     id->agno >= oagcount;
+	     id->agno--, *delta -= id->agsize) {
+
+		if (id->agno == nagcount - 1)
+			id->agsize = nb - (id->agno *
+					(xfs_rfsblock_t)mp->m_sb.sb_agblocks);
+		else
+			id->agsize = mp->m_sb.sb_agblocks;
+
+		error = xfs_ag_init_headers(mp, id);
+		if (error) {
+			xfs_buf_delwri_cancel(&id->buffer_list);
+			return error;
+		}
+	}
+	return xfs_buf_delwri_submit(&id->buffer_list);
+}
+
 /*
  * growfs operations
  */
@@ -74,36 +117,7 @@ xfs_growfs_data_private(
 	if (error)
 		return error;
 
-	/*
-	 * Write new AG headers to disk. Non-transactional, but need to be
-	 * written and completed prior to the growfs transaction being logged.
-	 * To do this, we use a delayed write buffer list and wait for
-	 * submission and IO completion of the list as a whole. This allows the
-	 * IO subsystem to merge all the AG headers in a single AG into a single
-	 * IO and hide most of the latency of the IO from us.
-	 *
-	 * This also means that if we get an error whilst building the buffer
-	 * list to write, we can cancel the entire list without having written
-	 * anything.
-	 */
-	INIT_LIST_HEAD(&id.buffer_list);
-	for (id.agno = nagcount - 1;
-	     id.agno >= oagcount;
-	     id.agno--, delta -= id.agsize) {
-
-		if (id.agno == nagcount - 1)
-			id.agsize = nb -
-				(id.agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
-		else
-			id.agsize = mp->m_sb.sb_agblocks;
-
-		error = xfs_ag_init_headers(mp, &id);
-		if (error) {
-			xfs_buf_delwri_cancel(&id.buffer_list);
-			goto out_trans_cancel;
-		}
-	}
-	error = xfs_buf_delwri_submit(&id.buffer_list);
+	error = xfs_resizefs_init_new_ags(mp, &id, oagcount, nagcount, &delta);
 	if (error)
 		goto out_trans_cancel;
 
-- 
2.27.0