[PATCH 25/35] xfs: create helpers for rtsummary block/wordcount computations

[cem@kernel.org]

From: "Darrick J. Wong" <djwong@kernel.org>

Source kernel commit: bd85af280de66a946022775a876edf0c553e3f35

Create helper functions that compute the number of blocks or words
necessary to store the rt summary file.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
---
 libxfs/xfs_rtbitmap.c | 29 +++++++++++++++++++++++++++++
 libxfs/xfs_rtbitmap.h |  7 +++++++
 2 files changed, 36 insertions(+)

diff --git a/libxfs/xfs_rtbitmap.c b/libxfs/xfs_rtbitmap.c
index f7be9ea5f..44064b6b3 100644
--- a/libxfs/xfs_rtbitmap.c
+++ b/libxfs/xfs_rtbitmap.c
@@ -1148,3 +1148,32 @@ xfs_rtbitmap_wordcount(
 	blocks = xfs_rtbitmap_blockcount(mp, rtextents);
 	return XFS_FSB_TO_B(mp, blocks) >> XFS_WORDLOG;
 }
+
+/* Compute the number of rtsummary blocks needed to track the given rt space. */
+xfs_filblks_t
+xfs_rtsummary_blockcount(
+	struct xfs_mount	*mp,
+	unsigned int		rsumlevels,
+	xfs_extlen_t		rbmblocks)
+{
+	unsigned long long	rsumwords;
+
+	rsumwords = (unsigned long long)rsumlevels * rbmblocks;
+	return XFS_B_TO_FSB(mp, rsumwords << XFS_WORDLOG);
+}
+
+/*
+ * Compute the number of rtsummary info words needed to populate every block of
+ * a summary file that is large enough to track the given rt space.
+ */
+unsigned long long
+xfs_rtsummary_wordcount(
+	struct xfs_mount	*mp,
+	unsigned int		rsumlevels,
+	xfs_extlen_t		rbmblocks)
+{
+	xfs_filblks_t		blocks;
+
+	blocks = xfs_rtsummary_blockcount(mp, rsumlevels, rbmblocks);
+	return XFS_FSB_TO_B(mp, blocks) >> XFS_WORDLOG;
+}
diff --git a/libxfs/xfs_rtbitmap.h b/libxfs/xfs_rtbitmap.h
index 02ee57f87..62138df6d 100644
--- a/libxfs/xfs_rtbitmap.h
+++ b/libxfs/xfs_rtbitmap.h
@@ -311,6 +311,11 @@ xfs_filblks_t xfs_rtbitmap_blockcount(struct xfs_mount *mp, xfs_rtbxlen_t
 		rtextents);
 unsigned long long xfs_rtbitmap_wordcount(struct xfs_mount *mp,
 		xfs_rtbxlen_t rtextents);
+
+xfs_filblks_t xfs_rtsummary_blockcount(struct xfs_mount *mp,
+		unsigned int rsumlevels, xfs_extlen_t rbmblocks);
+unsigned long long xfs_rtsummary_wordcount(struct xfs_mount *mp,
+		unsigned int rsumlevels, xfs_extlen_t rbmblocks);
 #else /* CONFIG_XFS_RT */
 # define xfs_rtfree_extent(t,b,l)			(-ENOSYS)
 # define xfs_rtfree_blocks(t,rb,rl)			(-ENOSYS)
@@ -325,6 +330,8 @@ xfs_rtbitmap_blockcount(struct xfs_mount *mp, xfs_rtbxlen_t rtextents)
 	return 0;
 }
 # define xfs_rtbitmap_wordcount(mp, r)			(0)
+# define xfs_rtsummary_blockcount(mp, l, b)		(0)
+# define xfs_rtsummary_wordcount(mp, l, b)		(0)
 #endif /* CONFIG_XFS_RT */
 
 #endif /* __XFS_RTBITMAP_H__ */
-- 
2.43.0