xfs: reserve AG space for the refcount btree root

djwong · djwong · commit d0e853f3600c · 2016-10-03T09:11:24.000-07:00
Reduce the max AG usable space size so that we always have space for
the refcount btree root.

Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
@@ -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;
 }

Original file line number	Diff line number	Diff line change
`@@ -128,6 +128,8 @@ xfs_alloc_ag_max_usable(`
`128`	`128`	`blocks++; /* finobt root block */`
`129`	`129`	`if (xfs_sb_version_hasrmapbt(&mp->m_sb))`
`130`	`130`	`blocks++; /* rmap root block */`
	`131`	`+ if (xfs_sb_version_hasreflink(&mp->m_sb))`
	`132`	`+ blocks++; /* refcount root block */`
`131`	`133`
`132`	`134`	`return mp->m_sb.sb_agblocks - blocks;`
`133`	`135`	`}`