xfs: move the min and max group block numbers to xfs_group

Move the min and max agblock numbers to the generic xfs_group structure
so that we can start building validators for extents within an rtgroup.
While we're at it, use check_add_overflow for the extent length
computation because that has much better overflow checking.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 30 insertions, 1 deletions

diff --git a/fs/xfs/libxfs/xfs_rtgroup.c b/fs/xfs/libxfs/xfs_rtgroup.c
index 624d8b25eba0..e74bb059f24f 100644
--- a/fs/xfs/libxfs/xfs_rtgroup.c
+++ b/fs/xfs/libxfs/xfs_rtgroup.c
@@ -34,6 +34,32 @@
 #include "xfs_metafile.h"
 #include "xfs_metadir.h"
 
+/* Find the first usable fsblock in this rtgroup. */
+static inline uint32_t
+xfs_rtgroup_min_block(
+	struct xfs_mount	*mp,
+	xfs_rgnumber_t		rgno)
+{
+	if (xfs_has_rtsb(mp) && rgno == 0)
+		return mp->m_sb.sb_rextsize;
+
+	return 0;
+}
+
+/* Precompute this group's geometry */
+void
+xfs_rtgroup_calc_geometry(
+	struct xfs_mount	*mp,
+	struct xfs_rtgroup	*rtg,
+	xfs_rgnumber_t		rgno,
+	xfs_rgnumber_t		rgcount,
+	xfs_rtbxlen_t		rextents)
+{
+	rtg->rtg_extents = __xfs_rtgroup_extents(mp, rgno, rgcount, rextents);
+	rtg_group(rtg)->xg_block_count = rtg->rtg_extents * mp->m_sb.sb_rextsize;
+	rtg_group(rtg)->xg_min_gbno = xfs_rtgroup_min_block(mp, rgno);
+}
+
 int
 xfs_rtgroup_alloc(
 	struct xfs_mount	*mp,
@@ -48,6 +74,8 @@ xfs_rtgroup_alloc(
 	if (!rtg)
 		return -ENOMEM;
 
+	xfs_rtgroup_calc_geometry(mp, rtg, rgno, rgcount, rextents);
+
 	error = xfs_group_insert(mp, rtg_group(rtg), rgno, XG_TYPE_RTG);
 	if (error)
 		goto out_free_rtg;
@@ -149,6 +177,7 @@ xfs_update_last_rtgroup_size(
 		return -EFSCORRUPTED;
 	rtg->rtg_extents = __xfs_rtgroup_extents(mp, prev_rgcount - 1,
 			mp->m_sb.sb_rgcount, mp->m_sb.sb_rextents);
+	rtg_group(rtg)->xg_block_count = rtg->rtg_extents * mp->m_sb.sb_rextsize;
 	xfs_rtgroup_rele(rtg);
 	return 0;
 }
@@ -223,7 +252,7 @@ xfs_rtgroup_get_geometry(
 	/* Fill out form. */
 	memset(rgeo, 0, sizeof(*rgeo));
 	rgeo->rg_number = rtg_rgno(rtg);
-	rgeo->rg_length = rtg->rtg_extents * rtg_mount(rtg)->m_sb.sb_rextsize;
+	rgeo->rg_length = rtg_group(rtg)->xg_block_count;
 	xfs_rtgroup_geom_health(rtg, rgeo);
 	return 0;
 }