xfs: refactor btree maxlevels computation
Create a common function to calculate the maximum height of a per-AG
btree. This will eventually be used by the rmapbt and refcountbt
code to calculate appropriate maxlevels values for each. This is
important because the verifiers and the transaction block
reservations depend on accurate estimates of how many blocks are
needed to satisfy a btree split.
We were mistakenly using the max bnobt height for all the btrees,
which creates a dangerous situation since the larger records and
keys in an rmapbt make it very possible that the rmapbt will be
taller than the bnobt and so we can run out of transaction block
reservation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 638657a..e56991d 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -1839,19 +1839,8 @@
xfs_alloc_compute_maxlevels(
xfs_mount_t *mp) /* file system mount structure */
{
- int level;
- uint maxblocks;
- uint maxleafents;
- int minleafrecs;
- int minnoderecs;
-
- maxleafents = (mp->m_sb.sb_agblocks + 1) / 2;
- minleafrecs = mp->m_alloc_mnr[0];
- minnoderecs = mp->m_alloc_mnr[1];
- maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
- for (level = 1; maxblocks > 1; level++)
- maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
- mp->m_ag_maxlevels = level;
+ mp->m_ag_maxlevels = xfs_btree_compute_maxlevels(mp, mp->m_alloc_mnr,
+ (mp->m_sb.sb_agblocks + 1) / 2);
}
/*
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 1f88e1c..a6779b3 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -4152,3 +4152,22 @@
return true;
}
+
+/*
+ * Calculate the number of btree levels needed to store a given number of
+ * records in a short-format btree.
+ */
+uint
+xfs_btree_compute_maxlevels(
+ struct xfs_mount *mp,
+ uint *limits,
+ unsigned long len)
+{
+ uint level;
+ unsigned long maxblocks;
+
+ maxblocks = (len + limits[0] - 1) / limits[0];
+ for (level = 1; maxblocks > 1; level++)
+ maxblocks = (maxblocks + limits[1] - 1) / limits[1];
+ return level;
+}
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 2e874be..785a996 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -474,5 +474,7 @@
bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp);
bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs);
+uint xfs_btree_compute_maxlevels(struct xfs_mount *mp, uint *limits,
+ unsigned long len);
#endif /* __XFS_BTREE_H__ */
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index e3c0af7..4b1e408 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -2394,20 +2394,11 @@
xfs_ialloc_compute_maxlevels(
xfs_mount_t *mp) /* file system mount structure */
{
- int level;
- uint maxblocks;
- uint maxleafents;
- int minleafrecs;
- int minnoderecs;
+ uint inodes;
- maxleafents = (1LL << XFS_INO_AGINO_BITS(mp)) >>
- XFS_INODES_PER_CHUNK_LOG;
- minleafrecs = mp->m_inobt_mnr[0];
- minnoderecs = mp->m_inobt_mnr[1];
- maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
- for (level = 1; maxblocks > 1; level++)
- maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
- mp->m_in_maxlevels = level;
+ inodes = (1LL << XFS_INO_AGINO_BITS(mp)) >> XFS_INODES_PER_CHUNK_LOG;
+ mp->m_in_maxlevels = xfs_btree_compute_maxlevels(mp, mp->m_inobt_mnr,
+ inodes);
}
/*