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.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_alloc.c | 3 +++
fs/xfs/libxfs/xfs_refcount_btree.c | 16 ++++++++++++++++
fs/xfs/libxfs/xfs_refcount_btree.h | 3 +++
3 files changed, 22 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 71dac69..637e2e7 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -36,6 +36,7 @@
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_log.h"
+#include "xfs_refcount_btree.h"
struct workqueue_struct *xfs_alloc_wq;
@@ -136,6 +137,8 @@ xfs_alloc_ag_max_usable(struct xfs_mount *mp)
/* rmap root block + full tree split on full AG */
blocks += 1 + (2 * mp->m_ag_maxlevels) - 1;
}
+ if (xfs_sb_version_hasreflink(&mp->m_sb))
+ blocks += xfs_refcountbt_max_btree_size(mp);
return mp->m_sb.sb_agblocks - blocks;
}
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index d7574cd..c785433 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -374,3 +374,19 @@ xfs_refcountbt_maxrecs(
return blocklen / (sizeof(struct xfs_refcount_key) +
sizeof(xfs_refcount_ptr_t));
}
+
+DEFINE_BTREE_SIZE_FN(refcountbt, m_refc_mxr, XFS_BTREE_MAXLEVELS);
+
+/**
+ * xfs_refcountbt_max_btree_size() -- Calculate the maximum refcount btree size.
+ */
+unsigned int
+xfs_refcountbt_max_btree_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_btree_size(mp, mp->m_sb.sb_agblocks);
+}
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.h b/fs/xfs/libxfs/xfs_refcount_btree.h
index d51dc1a..0f55544 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.h
+++ b/fs/xfs/libxfs/xfs_refcount_btree.h
@@ -62,4 +62,7 @@ extern struct xfs_btree_cur *xfs_refcountbt_init_cursor(struct xfs_mount *mp,
extern int xfs_refcountbt_maxrecs(struct xfs_mount *mp, int blocklen,
bool leaf);
+DECLARE_BTREE_SIZE_FN(refcountbt);
+extern unsigned int xfs_refcountbt_max_btree_size(struct xfs_mount *mp);
+
#endif /* __XFS_REFCOUNT_BTREE_H__ */
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