Ocfs2/move_extents: move a range of extent.

The moving range of __ocfs2_move_extent() was within one extent always, it
consists following parts:

1. Duplicates the clusters in pages to new_blkoffset, where extent to be moved.

2. Split the original extent with new extent, coalecse the nearby extents if possible.

3. Append old clusters to truncate log, or decrease_refcount if the extent was refcounted.

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
index e5ce1495dc77..d1bd5a347e9c 100644
--- a/fs/ocfs2/move_extents.c
+++ b/fs/ocfs2/move_extents.c
@@ -55,6 +55,106 @@ struct ocfs2_move_extents_context {
         struct ocfs2_cached_dealloc_ctxt dealloc;
 };
 
+static int __ocfs2_move_extent(handle_t *handle,
+                               struct ocfs2_move_extents_context *context,
+                               u32 cpos, u32 len, u32 p_cpos, u32 new_p_cpos,
+                               int ext_flags)
+{
+        int ret = 0, index;
+        struct inode *inode = context->inode;
+        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+        struct ocfs2_extent_rec *rec, replace_rec;
+        struct ocfs2_path *path = NULL;
+        struct ocfs2_extent_list *el;
+        u64 ino = ocfs2_metadata_cache_owner(context->et.et_ci);
+        u64 old_blkno = ocfs2_clusters_to_blocks(inode->i_sb, p_cpos);
+
+        ret = ocfs2_duplicate_clusters_by_page(handle, context->file, cpos,
+                                               p_cpos, new_p_cpos, len);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        memset(&replace_rec, 0, sizeof(replace_rec));
+        replace_rec.e_cpos = cpu_to_le32(cpos);
+        replace_rec.e_leaf_clusters = cpu_to_le16(len);
+        replace_rec.e_blkno = cpu_to_le64(ocfs2_clusters_to_blocks(inode->i_sb,
+                                                                   new_p_cpos));
+
+        path = ocfs2_new_path_from_et(&context->et);
+        if (!path) {
+                ret = -ENOMEM;
+                mlog_errno(ret);
+                goto out;
+        }
+
+        ret = ocfs2_find_path(INODE_CACHE(inode), path, cpos);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        el = path_leaf_el(path);
+
+        index = ocfs2_search_extent_list(el, cpos);
+        if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+                ocfs2_error(inode->i_sb,
+                            "Inode %llu has an extent at cpos %u which can no "
+                            "longer be found.\n",
+                            (unsigned long long)ino, cpos);
+                ret = -EROFS;
+                goto out;
+        }
+
+        rec = &el->l_recs[index];
+
+        BUG_ON(ext_flags != rec->e_flags);
+        /*
+         * after moving/defraging to new location, the extent is not going
+         * to be refcounted anymore.
+         */
+        replace_rec.e_flags = ext_flags & ~OCFS2_EXT_REFCOUNTED;
+
+        ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode),
+                                      context->et.et_root_bh,
+                                      OCFS2_JOURNAL_ACCESS_WRITE);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        ret = ocfs2_split_extent(handle, &context->et, path, index,
+                                 &replace_rec, context->meta_ac,
+                                 &context->dealloc);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        ocfs2_journal_dirty(handle, context->et.et_root_bh);
+
+        context->new_phys_cpos = new_p_cpos;
+
+        /*
+         * need I to append truncate log for old clusters?
+         */
+        if (old_blkno) {
+                if (ext_flags & OCFS2_EXT_REFCOUNTED)
+                        ret = ocfs2_decrease_refcount(inode, handle,
+                                        ocfs2_blocks_to_clusters(osb->sb,
+                                                                 old_blkno),
+                                        len, context->meta_ac,
+                                        &context->dealloc, 1);
+                else
+                        ret = ocfs2_truncate_log_append(osb, handle,
+                                                        old_blkno, len);
+        }
+
+out:
+        return ret;
+}
+
 /*
  * lock allocators, and reserving appropriate number of bits for
  * meta blocks and data clusters.