1 files changed, 11 insertions, 16 deletions

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index b8cbc8d5c7f7..f169d6b11d7f 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -49,7 +49,7 @@ void extent_map_tree_init(struct extent_map_tree *tree)
 struct extent_map *alloc_extent_map(void)
 {
         struct extent_map *em;
-        em = kmem_cache_alloc(extent_map_cache, GFP_NOFS);
+        em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS);
         if (!em)
                 return NULL;
         em->in_tree = 0;
@@ -198,16 +198,15 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
                         merge = rb_entry(rb, struct extent_map, rb_node);
                 if (rb && mergable_maps(merge, em)) {
                         em->start = merge->start;
+                        em->orig_start = merge->orig_start;
                         em->len += merge->len;
                         em->block_len += merge->block_len;
                         em->block_start = merge->block_start;
                         merge->in_tree = 0;
-                        if (merge->generation > em->generation) {
-                                em->mod_start = em->start;
-                                em->mod_len = em->len;
-                                em->generation = merge->generation;
-                                list_move(&em->list, &tree->modified_extents);
-                        }
+                        em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
+                        em->mod_start = merge->mod_start;
+                        em->generation = max(em->generation, merge->generation);
+                        list_move(&em->list, &tree->modified_extents);
 
                         list_del_init(&merge->list);
                         rb_erase(&merge->rb_node, &tree->map);
@@ -223,23 +222,19 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
                 em->block_len += merge->len;
                 rb_erase(&merge->rb_node, &tree->map);
                 merge->in_tree = 0;
-                if (merge->generation > em->generation) {
-                        em->mod_len = em->len;
-                        em->generation = merge->generation;
-                        list_move(&em->list, &tree->modified_extents);
-                }
+                em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
+                em->generation = max(em->generation, merge->generation);
                 list_del_init(&merge->list);
                 free_extent_map(merge);
         }
 }
 
 /**
- * unpint_extent_cache - unpin an extent from the cache
+ * unpin_extent_cache - unpin an extent from the cache
  * @tree:       tree to unpin the extent in
  * @start:      logical offset in the file
  * @len:        length of the extent
  * @gen:        generation that this extent has been modified in
- * @prealloc:   if this is set we need to clear the prealloc flag
  *
  * Called after an extent has been written to disk properly.  Set the generation
  * to the generation that actually added the file item to the inode so we know
@@ -266,9 +261,9 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
         em->mod_start = em->start;
         em->mod_len = em->len;
 
-        if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
+        if (test_bit(EXTENT_FLAG_FILLING, &em->flags)) {
                 prealloc = true;
-                clear_bit(EXTENT_FLAG_PREALLOC, &em->flags);
+                clear_bit(EXTENT_FLAG_FILLING, &em->flags);
         }
 
         try_merge_map(tree, em);