ocfs2: Add readhead during CoW.

In CoW, when we meet with a readahead page, we know
it is time to move the readahead window. So carry
out a new readahead.

Signed-off-by: Tao Ma <tao.ma@oracle.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index ad08c1134baa..47549f64224c 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -49,6 +49,7 @@
 
 struct ocfs2_cow_context {
         struct inode *inode;
+        struct file *file;
         u32 cow_start;
         u32 cow_len;
         struct ocfs2_extent_tree data_et;
@@ -2922,13 +2923,16 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
         u64 new_block = ocfs2_clusters_to_blocks(sb, new_cluster);
         struct page *page;
         pgoff_t page_index;
-        unsigned int from, to;
+        unsigned int from, to, readahead_pages;
         loff_t offset, end, map_end;
         struct address_space *mapping = context->inode->i_mapping;
 
         mlog(0, "old_cluster %u, new %u, len %u at offset %u\n", old_cluster,
              new_cluster, new_len, cpos);
 
+        readahead_pages =
+                (ocfs2_cow_contig_clusters(sb) <<
+                 OCFS2_SB(sb)->s_clustersize_bits) >> PAGE_CACHE_SHIFT;
         offset = ((loff_t)cpos) << OCFS2_SB(sb)->s_clustersize_bits;
         end = offset + (new_len << OCFS2_SB(sb)->s_clustersize_bits);
         /*
@@ -2959,6 +2963,14 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
                 if (PAGE_CACHE_SIZE <= OCFS2_SB(sb)->s_clustersize)
                         BUG_ON(PageDirty(page));
 
+                if (PageReadahead(page) && context->file) {
+                        page_cache_async_readahead(mapping,
+                                                   &context->file->f_ra,
+                                                   context->file,
+                                                   page, page_index,
+                                                   readahead_pages);
+                }
+
                 if (!PageUptodate(page)) {
                         ret = block_read_full_page(page, ocfs2_get_block);
                         if (ret) {
@@ -3478,6 +3490,7 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
         context->ref_root_bh = ref_root_bh;
         context->cow_duplicate_clusters = ocfs2_duplicate_clusters_by_page;
         context->get_clusters = ocfs2_di_get_clusters;
+        context->file = file;
 
         ocfs2_init_dinode_extent_tree(&context->data_et,
                                       INODE_CACHE(inode), di_bh);