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Commit 19b54ee6 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Dave Chinner
Browse files

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: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent e66a4c67

fs/xfs/libxfs/xfs_alloc.c

+2 −13
Original line number Diff line number Diff line
@@ -1839,19 +1839,8 @@ void 
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);

}



/*

fs/xfs/libxfs/xfs_btree.c

+19 −0
Original line number Diff line number Diff line
@@ -4152,3 +4152,22 @@ xfs_btree_sblock_verify( 


	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;

}

fs/xfs/libxfs/xfs_btree.h

+2 −0
Original line number Diff line number Diff line
@@ -474,5 +474,7 @@ static inline int xfs_btree_get_level(struct xfs_btree_block *block) 


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__ */

fs/xfs/libxfs/xfs_ialloc.c

+5 −14
Original line number Diff line number Diff line
@@ -2394,20 +2394,11 @@ void 
xfs_ialloc_compute_maxlevels(

	xfs_mount_t	*mp)		/* file system mount structure */

{

	int		level;

	uint		maxblocks;

	uint		maxleafents;

	int		minleafrecs;

	int		minnoderecs;



	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;

	uint		inodes;



	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);

}



/*