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[17/71] xfs: refcount btree requires more reserved space

Message ID 147216890040.4420.17914127056329841183.stgit@birch.djwong.org
State New, archived
Headers show

Commit Message

Darrick J. Wong Aug. 25, 2016, 11:48 p.m. UTC
The reference count btree is allocated from the free space, which
means that we have to ensure that an AG can't run out of free space
while performing a refcount operation.  In the pathological case each
AG block has its own refcntbt record, so we have to keep that much
space available.

v2: Calculate the maximum possible size of the rmap and refcount
btrees based on minimally-full btree blocks.  This increases the
per-AG block reservations to handle the worst case btree size.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 libxfs/xfs_alloc.c          |    3 +++
 libxfs/xfs_refcount_btree.c |   23 +++++++++++++++++++++++
 libxfs/xfs_refcount_btree.h |    4 ++++
 3 files changed, 30 insertions(+)
diff mbox

Patch

diff --git a/libxfs/xfs_alloc.c b/libxfs/xfs_alloc.c
index e754647..3151fbb 100644
--- a/libxfs/xfs_alloc.c
+++ b/libxfs/xfs_alloc.c
@@ -34,6 +34,7 @@ 
 #include "xfs_trace.h"
 #include "xfs_trans.h"
 #include "xfs_ag_resv.h"
+#include "xfs_refcount_btree.h"
 
 struct workqueue_struct *xfs_alloc_wq;
 
@@ -124,6 +125,8 @@  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;
 }
diff --git a/libxfs/xfs_refcount_btree.c b/libxfs/xfs_refcount_btree.c
index 04f8db0..568a2f8 100644
--- a/libxfs/xfs_refcount_btree.c
+++ b/libxfs/xfs_refcount_btree.c
@@ -380,3 +380,26 @@  xfs_refcountbt_compute_maxlevels(
 	mp->m_refc_maxlevels = xfs_btree_compute_maxlevels(mp,
 			mp->m_refc_mnr, mp->m_sb.sb_agblocks);
 }
+
+/* Calculate the refcount btree size for some records. */
+xfs_extlen_t
+xfs_refcountbt_calc_size(
+	struct xfs_mount	*mp,
+	unsigned long long	len)
+{
+	return xfs_btree_calc_size(mp, mp->m_refc_mnr, len);
+}
+
+/*
+ * Calculate the maximum refcount btree size.
+ */
+xfs_extlen_t
+xfs_refcountbt_max_size(
+	struct xfs_mount	*mp)
+{
+	/* Bail out if we're uninitialized, which can happen in mkfs. */
+	if (mp->m_refc_mxr[0] == 0)
+		return 0;
+
+	return xfs_refcountbt_calc_size(mp, mp->m_sb.sb_agblocks);
+}
diff --git a/libxfs/xfs_refcount_btree.h b/libxfs/xfs_refcount_btree.h
index 9e9ad7c..780b02f 100644
--- a/libxfs/xfs_refcount_btree.h
+++ b/libxfs/xfs_refcount_btree.h
@@ -64,4 +64,8 @@  extern int xfs_refcountbt_maxrecs(struct xfs_mount *mp, int blocklen,
 		bool leaf);
 extern void xfs_refcountbt_compute_maxlevels(struct xfs_mount *mp);
 
+extern xfs_extlen_t xfs_refcountbt_calc_size(struct xfs_mount *mp,
+		unsigned long long len);
+extern xfs_extlen_t xfs_refcountbt_max_size(struct xfs_mount *mp);
+
 #endif	/* __XFS_REFCOUNT_BTREE_H__ */