ocfs2: Enable cross extent block merge.

In ocfs2_figure_merge_contig_type, we judge whether there exists
a cross extent block merge and enable it by setting CONTIG_LEFT
and CONTIG_RIGHT accordingly.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 86 insertions, 8 deletions

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index f63cb32e224d..7d81aa6f5672 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -3782,20 +3782,57 @@ out:
 }
 
 static enum ocfs2_contig_type
-ocfs2_figure_merge_contig_type(struct inode *inode,
+ocfs2_figure_merge_contig_type(struct inode *inode, struct ocfs2_path *path,
                                struct ocfs2_extent_list *el, int index,
                                struct ocfs2_extent_rec *split_rec)
 {
-        struct ocfs2_extent_rec *rec;
+        int status;
         enum ocfs2_contig_type ret = CONTIG_NONE;
+        u32 left_cpos, right_cpos;
+        struct ocfs2_extent_rec *rec = NULL;
+        struct ocfs2_extent_list *new_el;
+        struct ocfs2_path *left_path = NULL, *right_path = NULL;
+        struct buffer_head *bh;
+        struct ocfs2_extent_block *eb;
+
+        if (index > 0) {
+                rec = &el->l_recs[index - 1];
+        } else if (path->p_tree_depth > 0) {
+                status = ocfs2_find_cpos_for_left_leaf(inode->i_sb,
+                                                       path, &left_cpos);
+                if (status)
+                        goto out;
+
+                if (left_cpos != 0) {
+                        left_path = ocfs2_new_path(path_root_bh(path),
+                                                   path_root_el(path));
+                        if (!left_path)
+                                goto out;
+
+                        status = ocfs2_find_path(inode, left_path, left_cpos);
+                        if (status)
+                                goto out;
+
+                        new_el = path_leaf_el(left_path);
+
+                        if (le16_to_cpu(new_el->l_next_free_rec) !=
+                            le16_to_cpu(new_el->l_count)) {
+                                bh = path_leaf_bh(left_path);
+                                eb = (struct ocfs2_extent_block *)bh->b_data;
+                                OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb,
+                                                                 eb);
+                                goto out;
+                        }
+                        rec = &new_el->l_recs[
+                                le16_to_cpu(new_el->l_next_free_rec) - 1];
+                }
+        }
 
         /*
          * We're careful to check for an empty extent record here -
          * the merge code will know what to do if it sees one.
          */
-
-        if (index > 0) {
-                rec = &el->l_recs[index - 1];
+        if (rec) {
                 if (index == 1 && ocfs2_is_empty_extent(rec)) {
                         if (split_rec->e_cpos == el->l_recs[index].e_cpos)
                                 ret = CONTIG_RIGHT;
@@ -3804,10 +3841,45 @@ ocfs2_figure_merge_contig_type(struct inode *inode,
                 }
         }
 
-        if (index < (le16_to_cpu(el->l_next_free_rec) - 1)) {
+        rec = NULL;
+        if (index < (le16_to_cpu(el->l_next_free_rec) - 1))
+                rec = &el->l_recs[index + 1];
+        else if (le16_to_cpu(el->l_next_free_rec) == le16_to_cpu(el->l_count) &&
+                 path->p_tree_depth > 0) {
+                status = ocfs2_find_cpos_for_right_leaf(inode->i_sb,
+                                                        path, &right_cpos);
+                if (status)
+                        goto out;
+
+                if (right_cpos == 0)
+                        goto out;
+
+                right_path = ocfs2_new_path(path_root_bh(path),
+                                            path_root_el(path));
+                if (!right_path)
+                        goto out;
+
+                status = ocfs2_find_path(inode, right_path, right_cpos);
+                if (status)
+                        goto out;
+
+                new_el = path_leaf_el(right_path);
+                rec = &new_el->l_recs[0];
+                if (ocfs2_is_empty_extent(rec)) {
+                        if (le16_to_cpu(new_el->l_next_free_rec) <= 1) {
+                                bh = path_leaf_bh(right_path);
+                                eb = (struct ocfs2_extent_block *)bh->b_data;
+                                OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb,
+                                                                 eb);
+                                goto out;
+                        }
+                        rec = &new_el->l_recs[1];
+                }
+        }
+
+        if (rec) {
                 enum ocfs2_contig_type contig_type;
 
-                rec = &el->l_recs[index + 1];
                 contig_type = ocfs2_extent_contig(inode, rec, split_rec);
 
                 if (contig_type == CONTIG_LEFT && ret == CONTIG_RIGHT)
@@ -3816,6 +3888,12 @@ ocfs2_figure_merge_contig_type(struct inode *inode,
                         ret = contig_type;
         }
 
+out:
+        if (left_path)
+                ocfs2_free_path(left_path);
+        if (right_path)
+                ocfs2_free_path(right_path);
+
         return ret;
 }
 
@@ -4278,7 +4356,7 @@ static int __ocfs2_mark_extent_written(struct inode *inode,
                 goto out;
         }
 
-        ctxt.c_contig_type = ocfs2_figure_merge_contig_type(inode, el,
+        ctxt.c_contig_type = ocfs2_figure_merge_contig_type(inode, path, el,
                                                             split_index,
                                                             split_rec);