[RFC 2/4] xfs: transaction support for sb_agblocks updates

[Brian Foster <bfoster@redhat.com>]

Support transactional changes to superblock agblocks and related
fields.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/libxfs/xfs_shared.h |  1 +
 fs/xfs/xfs_trans.c         | 15 +++++++++++++++
 fs/xfs/xfs_trans.h         |  1 +
 3 files changed, 17 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index 33b84a3a83ff..b8e80827a010 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -157,6 +157,7 @@ void	xfs_log_get_max_trans_res(struct xfs_mount *mp,
 #define	XFS_TRANS_SB_RBLOCKS		0x00000800
 #define	XFS_TRANS_SB_REXTENTS		0x00001000
 #define	XFS_TRANS_SB_REXTSLOG		0x00002000
+#define	XFS_TRANS_SB_AGBLOCKS		0x00004000
 
 /*
  * Here we centralize the specification of XFS meta-data buffer reference count
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index bdf3704dc301..34a9896ec398 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -433,6 +433,9 @@ xfs_trans_mod_sb(
 	case XFS_TRANS_SB_DBLOCKS:
 		tp->t_dblocks_delta += delta;
 		break;
+	case XFS_TRANS_SB_AGBLOCKS:
+		tp->t_agblocks_delta += delta;
+		break;
 	case XFS_TRANS_SB_AGCOUNT:
 		ASSERT(delta > 0);
 		tp->t_agcount_delta += delta;
@@ -526,6 +529,16 @@ xfs_trans_apply_sb_deltas(
 		be64_add_cpu(&sbp->sb_dblocks, tp->t_dblocks_delta);
 		whole = 1;
 	}
+	if (tp->t_agblocks_delta) {
+		xfs_agblock_t		agblocks;
+
+		agblocks = be32_to_cpu(sbp->sb_agblocks);
+		agblocks += tp->t_agblocks_delta;
+
+		sbp->sb_agblocks = cpu_to_be32(agblocks);
+		sbp->sb_agblklog = ilog2(roundup_pow_of_two(agblocks));
+		whole = 1;
+	}
 	if (tp->t_agcount_delta) {
 		be32_add_cpu(&sbp->sb_agcount, tp->t_agcount_delta);
 		whole = 1;
@@ -657,6 +670,8 @@ xfs_trans_unreserve_and_mod_sb(
 	 * incore reservations.
 	 */
 	mp->m_sb.sb_dblocks += tp->t_dblocks_delta;
+	mp->m_sb.sb_agblocks += tp->t_agblocks_delta;
+	mp->m_sb.sb_agblklog = ilog2(roundup_pow_of_two(mp->m_sb.sb_agblocks));
 	mp->m_sb.sb_agcount += tp->t_agcount_delta;
 	mp->m_sb.sb_imax_pct += tp->t_imaxpct_delta;
 	mp->m_sb.sb_rextsize += tp->t_rextsize_delta;
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index f06cc0f41665..11462406988d 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -141,6 +141,7 @@ typedef struct xfs_trans {
 	int64_t			t_frextents_delta;/* superblock freextents chg*/
 	int64_t			t_res_frextents_delta; /* on-disk only chg */
 	int64_t			t_dblocks_delta;/* superblock dblocks change */
+	int64_t			t_agblocks_delta;/* superblock agblocks change */
 	int64_t			t_agcount_delta;/* superblock agcount change */
 	int64_t			t_imaxpct_delta;/* superblock imaxpct change */
 	int64_t			t_rextsize_delta;/* superblock rextsize chg */
-- 
2.46.2