1 files changed, 41 insertions, 2 deletions

diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index efdd75607406..b5f9160e93e9 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;
@@ -2932,13 +2933,16 @@ 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);
         /*
@@ -2969,6 +2973,14 @@ 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) {
@@ -3409,12 +3421,35 @@ static int ocfs2_replace_cow(struct ocfs2_cow_context *context)
         return ret;
 }
 
+static void ocfs2_readahead_for_cow(struct inode *inode,
+                                    struct file *file,
+                                    u32 start, u32 len)
+{
+        struct address_space *mapping;
+        pgoff_t index;
+        unsigned long num_pages;
+        int cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+
+        if (!file)
+                return;
+
+        mapping = file->f_mapping;
+        num_pages = (len << cs_bits) >> PAGE_CACHE_SHIFT;
+        if (!num_pages)
+                num_pages = 1;
+
+        index = ((loff_t)start << cs_bits) >> PAGE_CACHE_SHIFT;
+        page_cache_sync_readahead(mapping, &file->f_ra, file,
+                                  index, num_pages);
+}
+
 /*
  * Starting at cpos, try to CoW write_len clusters.  Don't CoW
  * past max_cpos.  This will stop when it runs into a hole or an
  * unrefcounted extent.
  */
 static int ocfs2_refcount_cow_hunk(struct inode *inode,
+                                   struct file *file,
                                    struct buffer_head *di_bh,
                                    u32 cpos, u32 write_len, u32 max_cpos)
 {
@@ -3443,6 +3478,8 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
 
         BUG_ON(cow_len == 0);
 
+        ocfs2_readahead_for_cow(inode, file, cow_start, cow_len);
+
         context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
         if (!context) {
                 ret = -ENOMEM;
@@ -3464,6 +3501,7 @@ 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);
@@ -3492,6 +3530,7 @@ out:
  * clusters between cpos and cpos+write_len are safe to modify.
  */
 int ocfs2_refcount_cow(struct inode *inode,
+                       struct file *file,
                        struct buffer_head *di_bh,
                        u32 cpos, u32 write_len, u32 max_cpos)
 {
@@ -3511,7 +3550,7 @@ int ocfs2_refcount_cow(struct inode *inode,
                         num_clusters = write_len;
 
                 if (ext_flags & OCFS2_EXT_REFCOUNTED) {
-                        ret = ocfs2_refcount_cow_hunk(inode, di_bh, cpos,
+                        ret = ocfs2_refcount_cow_hunk(inode, file, di_bh, cpos,
                                                       num_clusters, max_cpos);
                         if (ret) {
                                 mlog_errno(ret);