[PATCH 2/5] libxfs: refactor the btree size calculator code

Darrick J. Wong
2016-01-23T00:35:15Z

Create a macro to generate btree height calculator functions.
This will be used (much) later when we get to the refcount
btree.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
libxfs/xfs_bmap.c | 18 +-----------------
libxfs/xfs_bmap_btree.c | 9 +++++++++
libxfs/xfs_bmap_btree.h | 3 +++
libxfs/xfs_btree.c | 28 ++++++++++++++++++++++++++++
libxfs/xfs_btree.h | 3 +++
5 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index aef7cf3..c134765 100644
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -172,25 +172,9 @@ xfs_bmap_worst_indlen(
xfs_inode_t *ip, /* incore inode pointer */
xfs_filblks_t len) /* delayed extent length */
{
- int level; /* btree level number */
- int maxrecs; /* maximum record count at this level */
- xfs_mount_t *mp; /* mount structure */
xfs_filblks_t rval; /* return value */

- mp = ip->i_mount;
- maxrecs = mp->m_bmap_dmxr[0];
- for (level = 0, rval = 0;
- level < XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK);
- level++) {
- len += maxrecs - 1;
- do_div(len, maxrecs);
- rval += len;
- if (len == 1)
- return rval + XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) -
- level - 1;
- if (level == 0)
- maxrecs = mp->m_bmap_dmxr[1];
- }
+ rval = xfs_bmbt_calc_size(ip->i_mount, len);
return rval;
}

diff --git a/libxfs/xfs_bmap_btree.c b/libxfs/xfs_bmap_btree.c
index 2ef1836..3c595e2 100644
--- a/libxfs/xfs_bmap_btree.c
+++ b/libxfs/xfs_bmap_btree.c
@@ -880,3 +880,12 @@ xfs_bmbt_change_owner(
xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
return error;
}
+
+xfs_filblks_t
+xfs_bmbt_calc_size(
+ struct xfs_mount *mp,
+ unsigned long len)
+{
+ return xfs_btree_calc_size(mp, mp->m_bmap_dmxr,
+ XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), len);
+}
diff --git a/libxfs/xfs_bmap_btree.h b/libxfs/xfs_bmap_btree.h
index 819a8a4..04bc6e2 100644
--- a/libxfs/xfs_bmap_btree.h
+++ b/libxfs/xfs_bmap_btree.h
@@ -140,4 +140,7 @@ extern int xfs_bmbt_change_owner(struct xfs_trans *tp, struct xfs_inode *ip,
extern struct xfs_btree_cur *xfs_bmbt_init_cursor(struct xfs_mount *,
struct xfs_trans *, struct xfs_inode *, int);

+extern xfs_filblks_t xfs_bmbt_calc_size(struct xfs_mount *mp,
+ unsigned long len);
+
#endif /* __XFS_BMAP_BTREE_H__ */
diff --git a/libxfs/xfs_btree.c b/libxfs/xfs_btree.c
index 658f27e..d5f16c5 100644
--- a/libxfs/xfs_btree.c
+++ b/libxfs/xfs_btree.c
@@ -4081,6 +4081,34 @@ xfs_btree_change_owner(
return 0;
}

+/*
+ * xfs_btree_calc_size() -- Calculate the number of blocks needed to store
+ * a given number of records.
+ */
+xfs_filblks_t
+xfs_btree_calc_size(
+ struct xfs_mount *mp,
+ uint *limits,
+ int maxlevels,
+ unsigned long len)
+{
+ int level;
+ int maxrecs;
+ xfs_filblks_t rval;
+
+ maxrecs = limits[0];
+ for (level = 0, rval = 0; level < maxlevels; level++) {
+ len += maxrecs - 1;
+ do_div(len, maxrecs);
+ rval += len;
+ if (len == 1)
+ return rval + maxlevels - level - 1;
+ if (level == 0)
+ maxrecs = limits[1];
+ }
+ return rval;
+}
+
/**
* xfs_btree_sblock_v5hdr_verify() -- verify the v5 fields of a short-format
* btree block
diff --git a/libxfs/xfs_btree.h b/libxfs/xfs_btree.h
index 48cb251..b25ffd3 100644
--- a/libxfs/xfs_btree.h
+++ b/libxfs/xfs_btree.h
@@ -465,6 +465,9 @@ static inline int xfs_btree_get_level(struct xfs_btree_block *block)
#define XFS_BTREE_TRACE_ARGR(c, r)
#define XFS_BTREE_TRACE_CURSOR(c, t)

+xfs_filblks_t xfs_btree_calc_size(struct xfs_mount *mp, uint *limits,
+ int maxlevels, unsigned long len);
+
bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp);
bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs);