[PATCH 15/21] xfs: pass back updated nb from xfs_growfs_compute_deltas

[Andrey Albershteyn <aalbersh@kernel.org>]

From: Christoph Hellwig <hch@lst.de>

Source kernel commit: 4cb6e89a3d901d4da515977e55f9a9a779238660

xfs_growfs_compute_deltas can update nb for corner cases like a number
of blocks that would create a less the minimal sized AG, or running
past the max AG limit.  Pass back the calculated value to the caller,
as it relies on to calculate the new number of perag structures.

Note that the grown file system size is not affected by this
miscalculation as it uses the passed back delta value.

Fixes: a49b7ff63f98 ("xfs: Refactoring the nagcount and delta calculation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
---
 libxfs/xfs_ag.c | 10 +++++-----
 libxfs/xfs_ag.h |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c
index 1c75ef510567..fb8c9bb3df82 100644
--- a/libxfs/xfs_ag.c
+++ b/libxfs/xfs_ag.c
@@ -864,7 +864,7 @@ resv_err:
 void
 xfs_growfs_compute_deltas(
 	struct xfs_mount	*mp,
-	xfs_rfsblock_t		nb,
+	xfs_rfsblock_t		*nb,
 	int64_t			*deltap,
 	xfs_agnumber_t		*nagcountp)
 {
@@ -872,19 +872,19 @@ xfs_growfs_compute_deltas(
 	int64_t		delta;
 	xfs_agnumber_t	nagcount;
 
-	nb_div = nb;
+	nb_div = *nb;
 	nb_mod = do_div(nb_div, mp->m_sb.sb_agblocks);
 	if (nb_mod && nb_mod >= XFS_MIN_AG_BLOCKS)
 		nb_div++;
 	else if (nb_mod)
-		nb = nb_div * mp->m_sb.sb_agblocks;
+		*nb = nb_div * mp->m_sb.sb_agblocks;
 
 	if (nb_div > XFS_MAX_AGNUMBER + 1) {
 		nb_div = XFS_MAX_AGNUMBER + 1;
-		nb = nb_div * mp->m_sb.sb_agblocks;
+		*nb = nb_div * mp->m_sb.sb_agblocks;
 	}
 	nagcount = nb_div;
-	delta = nb - mp->m_sb.sb_dblocks;
+	delta = *nb - mp->m_sb.sb_dblocks;
 	*deltap = delta;
 	*nagcountp = nagcount;
 }
diff --git a/libxfs/xfs_ag.h b/libxfs/xfs_ag.h
index 16a9b43a3c27..8aa4266c5571 100644
--- a/libxfs/xfs_ag.h
+++ b/libxfs/xfs_ag.h
@@ -330,7 +330,7 @@ int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id);
 int xfs_ag_shrink_space(struct xfs_perag *pag, struct xfs_trans **tpp,
 			xfs_extlen_t delta);
 void
-xfs_growfs_compute_deltas(struct xfs_mount *mp, xfs_rfsblock_t nb,
+xfs_growfs_compute_deltas(struct xfs_mount *mp, xfs_rfsblock_t *nb,
 			int64_t *deltap, xfs_agnumber_t *nagcountp);
 int xfs_ag_extend_space(struct xfs_perag *pag, struct xfs_trans *tp,
 			xfs_extlen_t len);
-- 
2.55.0