xfs: reserve AG space for the refcount btree root



Reduce the max AG usable space size so that we always have space for
the refcount btree root.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

parent a90c00f0

fs/xfs/libxfs/xfs_alloc.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -128,6 +128,8 @@ xfs_alloc_ag_max_usable(
		blocks++; /* finobt root block */
		if (xfs_sb_version_hasrmapbt(&mp->m_sb))
		blocks++; /* rmap root block */
		if (xfs_sb_version_hasreflink(&mp->m_sb))
		blocks++; /* refcount root block */

		return mp->m_sb.sb_agblocks - blocks;
		}