1 files changed, 110 insertions, 0 deletions

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 579659bae6c5..cacfc118b71c 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,