Commit 16eaab83 authored by Brian Foster's avatar Brian Foster Committed by Darrick J. Wong
Browse files

xfs: introduce in-core global counter of allocbt blocks 



Introduce an in-core counter to track the sum of all allocbt blocks
used by the filesystem. This value is currently tracked per-ag via
the ->agf_btreeblks field in the AGF, which also happens to include
rmapbt blocks. A global, in-core count of allocbt blocks is required
to identify the subset of global ->m_fdblocks that consists of
unavailable blocks currently used for allocation btrees. To support
this calculation at block reservation time, construct a similar
global counter for allocbt blocks, populate it on first read of each
AGF and update it as allocbt blocks are used and released.

Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarChandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: default avatarAllison Henderson <allison.henderson@oracle.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 2675ad38

fs/xfs/libxfs/xfs_alloc.c

+14 −0
Original line number Diff line number Diff line
@@ -3033,6 +3033,7 @@ xfs_alloc_read_agf( 
	struct xfs_agf		*agf;		/* ag freelist header */

	struct xfs_perag	*pag;		/* per allocation group data */

	int			error;

	int			allocbt_blks;



	trace_xfs_alloc_read_agf(mp, agno);
@@ -3063,6 +3064,19 @@ xfs_alloc_read_agf( 
		pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);

		pag->pagf_init = 1;

		pag->pagf_agflreset = xfs_agfl_needs_reset(mp, agf);



		/*

		 * Update the in-core allocbt counter. Filter out the rmapbt

		 * subset of the btreeblks counter because the rmapbt is managed

		 * by perag reservation. Subtract one for the rmapbt root block

		 * because the rmap counter includes it while the btreeblks

		 * counter only tracks non-root blocks.

		 */

		allocbt_blks = pag->pagf_btreeblks;

		if (xfs_sb_version_hasrmapbt(&mp->m_sb))

			allocbt_blks -= be32_to_cpu(agf->agf_rmap_blocks) - 1;

		if (allocbt_blks > 0)

			atomic64_add(allocbt_blks, &mp->m_allocbt_blks);

	}

#ifdef DEBUG

	else if (!XFS_FORCED_SHUTDOWN(mp)) {

fs/xfs/libxfs/xfs_alloc_btree.c

+2 −0
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ xfs_allocbt_alloc_block( 
		return 0;

	}



	atomic64_inc(&cur->bc_mp->m_allocbt_blks);

	xfs_extent_busy_reuse(cur->bc_mp, cur->bc_ag.agno, bno, 1, false);



	new->s = cpu_to_be32(bno);
@@ -94,6 +95,7 @@ xfs_allocbt_free_block( 
	if (error)

		return error;



	atomic64_dec(&cur->bc_mp->m_allocbt_blks);

	xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,

			      XFS_EXTENT_BUSY_SKIP_DISCARD);

	return 0;

fs/xfs/xfs_mount.h

+6 −0
Original line number Diff line number Diff line
@@ -170,6 +170,12 @@ typedef struct xfs_mount { 
	 * extents or anything related to the rt device.

	 */

	struct percpu_counter	m_delalloc_blks;

	/*

	 * Global count of allocation btree blocks in use across all AGs. Only

	 * used when perag reservation is enabled. Helps prevent block

	 * reservation from attempting to reserve allocation btree blocks.

	 */

	atomic64_t		m_allocbt_blks;



	struct radix_tree_root	m_perag_tree;	/* per-ag accounting info */

	spinlock_t		m_perag_lock;	/* lock for m_perag_tree */