ocfs2: Grow discontig block groups in one transaction.

Rather than extending the transaction every time we add an extent to a
discontiguous block group, we grab enough credits to fill the extent
list up front.  This means we can free the bits in the same transaction
if we end up not getting enough space.

Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
index 7dc56561c9ae..b5baaa8e710f 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -561,6 +561,18 @@ static inline int ocfs2_calc_group_alloc_credits(struct super_block *sb,
         return blocks;
 }
 
+/*
+ * Allocating a discontiguous block group requires the credits from
+ * ocfs2_calc_group_alloc_credits() as well as enough credits to fill
+ * the group descriptor's extent list.  The caller already has started
+ * the transaction with ocfs2_calc_group_alloc_credits().  They extend
+ * it with these credits.
+ */
+static inline int ocfs2_calc_bg_discontig_credits(struct super_block *sb)
+{
+        return ocfs2_extent_recs_per_gd(sb);
+}
+
 static inline int ocfs2_calc_tree_trunc_credits(struct super_block *sb,
                                                 unsigned int clusters_to_del,
                                                 struct ocfs2_dinode *fe,