1 files changed, 9 insertions, 0 deletions

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 74b2a29880d..fd3ebfb8c3c 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -184,6 +184,13 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next)
         if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
                 return 0;
 
+        /*
+         * don't merge compressed extents, we need to know their
+         * actual size
+         */
+        if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
+                return 0;
+
         if (extent_map_end(prev) == next->start &&
             prev->flags == next->flags &&
             prev->bdev == next->bdev &&
@@ -239,6 +246,7 @@ int add_extent_mapping(struct extent_map_tree *tree,
                 if (rb && mergable_maps(merge, em)) {
                         em->start = merge->start;
                         em->len += merge->len;
+                        em->block_len += merge->block_len;
                         em->block_start = merge->block_start;
                         merge->in_tree = 0;
                         rb_erase(&merge->rb_node, &tree->map);
@@ -250,6 +258,7 @@ int add_extent_mapping(struct extent_map_tree *tree,
                 merge = rb_entry(rb, struct extent_map, rb_node);
         if (rb && mergable_maps(em, merge)) {
                 em->len += merge->len;
+                em->block_len += merge->len;
                 rb_erase(&merge->rb_node, &tree->map);
                 merge->in_tree = 0;
                 free_extent_map(merge);