From 0eb8d47e69a2211a36643b180f1843ef45f6017d Mon Sep 17 00:00:00 2001
From: Tao Ma <tao.ma@oracle.com>
Date: Mon, 18 Aug 2008 17:38:45 +0800
Subject: ocfs2: Make high level btree extend code generic

Factor out the non-inode specifics of ocfs2_do_extend_allocation() into a more generic
function, ocfs2_do_cluster_allocation(). ocfs2_do_extend_allocation calls
ocfs2_do_cluster_allocation() now, but the latter can be used for other
btree types as well.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
---
 fs/ocfs2/alloc.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)

(limited to 'fs/ocfs2/alloc.c')

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 579659bae6c..cacfc118b71 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -4293,6 +4293,116 @@ bail:
 	return status;
 }
 
+/*
+ * Allcate and add clusters into the extent b-tree.
+ * The new clusters(clusters_to_add) will be inserted at logical_offset.
+ * The extent b-tree's root is root_el and it should be in root_bh, and
+ * it is not limited to the file storage. Any extent tree can use this
+ * function if it implements the proper ocfs2_extent_tree.
+ */
+int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
+				struct inode *inode,
+				u32 *logical_offset,
+				u32 clusters_to_add,
+				int mark_unwritten,
+				struct buffer_head *root_bh,
+				struct ocfs2_extent_list *root_el,
+				handle_t *handle,
+				struct ocfs2_alloc_context *data_ac,
+				struct ocfs2_alloc_context *meta_ac,
+				enum ocfs2_alloc_restarted *reason_ret,
+				enum ocfs2_extent_tree_type type)
+{
+	int status = 0;
+	int free_extents;
+	enum ocfs2_alloc_restarted reason = RESTART_NONE;
+	u32 bit_off, num_bits;
+	u64 block;
+	u8 flags = 0;
+
+	BUG_ON(!clusters_to_add);
+
+	if (mark_unwritten)
+		flags = OCFS2_EXT_UNWRITTEN;
+
+	free_extents = ocfs2_num_free_extents(osb, inode, root_bh, type);
+	if (free_extents < 0) {
+		status = free_extents;
+		mlog_errno(status);
+		goto leave;
+	}
+
+	/* there are two cases which could cause us to EAGAIN in the
+	 * we-need-more-metadata case:
+	 * 1) we haven't reserved *any*
+	 * 2) we are so fragmented, we've needed to add metadata too
+	 *    many times. */
+	if (!free_extents && !meta_ac) {
+		mlog(0, "we haven't reserved any metadata!\n");
+		status = -EAGAIN;
+		reason = RESTART_META;
+		goto leave;
+	} else if ((!free_extents)
+		   && (ocfs2_alloc_context_bits_left(meta_ac)
+		       < ocfs2_extend_meta_needed(root_el))) {
+		mlog(0, "filesystem is really fragmented...\n");
+		status = -EAGAIN;
+		reason = RESTART_META;
+		goto leave;
+	}
+
+	status = __ocfs2_claim_clusters(osb, handle, data_ac, 1,
+					clusters_to_add, &bit_off, &num_bits);
+	if (status < 0) {
+		if (status != -ENOSPC)
+			mlog_errno(status);
+		goto leave;
+	}
+
+	BUG_ON(num_bits > clusters_to_add);
+
+	/* reserve our write early -- insert_extent may update the inode */
+	status = ocfs2_journal_access(handle, inode, root_bh,
+				      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (status < 0) {
+		mlog_errno(status);
+		goto leave;
+	}
+
+	block = ocfs2_clusters_to_blocks(osb->sb, bit_off);
+	mlog(0, "Allocating %u clusters at block %u for inode %llu\n",
+	     num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);
+	status = ocfs2_insert_extent(osb, handle, inode, root_bh,
+				     *logical_offset, block, num_bits,
+				     flags, meta_ac, type);
+	if (status < 0) {
+		mlog_errno(status);
+		goto leave;
+	}
+
+	status = ocfs2_journal_dirty(handle, root_bh);
+	if (status < 0) {
+		mlog_errno(status);
+		goto leave;
+	}
+
+	clusters_to_add -= num_bits;
+	*logical_offset += num_bits;
+
+	if (clusters_to_add) {
+		mlog(0, "need to alloc once more, wanted = %u\n",
+		     clusters_to_add);
+		status = -EAGAIN;
+		reason = RESTART_TRANS;
+	}
+
+leave:
+	mlog_exit(status);
+	if (reason_ret)
+		*reason_ret = reason;
+	return status;
+}
+
 static void ocfs2_make_right_split_rec(struct super_block *sb,
 				       struct ocfs2_extent_rec *split_rec,
 				       u32 cpos,
-- 
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