btrfs: Check mergeable free space when removing a cluster

After returing extents from a cluster to the block group, some
extents in the block group may be mergeable.

Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

1 files changed, 20 insertions, 6 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index cf67dc3b7bf8..a5501edc3c9f 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -987,11 +987,18 @@ tree_search_offset(struct btrfs_block_group_cache *block_group,
         return entry;
 }
 
-static void unlink_free_space(struct btrfs_block_group_cache *block_group,
-                              struct btrfs_free_space *info)
+static inline void
+__unlink_free_space(struct btrfs_block_group_cache *block_group,
+                    struct btrfs_free_space *info)
 {
         rb_erase(&info->offset_index, &block_group->free_space_offset);
         block_group->free_extents--;
+}
+
+static void unlink_free_space(struct btrfs_block_group_cache *block_group,
+                              struct btrfs_free_space *info)
+{
+        __unlink_free_space(block_group, info);
         block_group->free_space -= info->bytes;
 }
 
@@ -1364,7 +1371,7 @@ out:
 }
 
 bool try_merge_free_space(struct btrfs_block_group_cache *block_group,
-                          struct btrfs_free_space *info)
+                          struct btrfs_free_space *info, bool update_stat)
 {
         struct btrfs_free_space *left_info;
         struct btrfs_free_space *right_info;
@@ -1385,7 +1392,10 @@ bool try_merge_free_space(struct btrfs_block_group_cache *block_group,
                 left_info = tree_search_offset(block_group, offset - 1, 0, 0);
 
         if (right_info && !right_info->bitmap) {
-                unlink_free_space(block_group, right_info);
+                if (update_stat)
+                        unlink_free_space(block_group, right_info);
+                else
+                        __unlink_free_space(block_group, right_info);
                 info->bytes += right_info->bytes;
                 kfree(right_info);
                 merged = true;
@@ -1393,7 +1403,10 @@ bool try_merge_free_space(struct btrfs_block_group_cache *block_group,
 
         if (left_info && !left_info->bitmap &&
             left_info->offset + left_info->bytes == offset) {
-                unlink_free_space(block_group, left_info);
+                if (update_stat)
+                        unlink_free_space(block_group, left_info);
+                else
+                        __unlink_free_space(block_group, left_info);
                 info->offset = left_info->offset;
                 info->bytes += left_info->bytes;
                 kfree(left_info);
@@ -1418,7 +1431,7 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
 
         spin_lock(&block_group->tree_lock);
 
-        if (try_merge_free_space(block_group, info))
+        if (try_merge_free_space(block_group, info, true))
                 goto link;
 
         /*
@@ -1636,6 +1649,7 @@ __btrfs_return_cluster_to_free_space(
                 node = rb_next(&entry->offset_index);
                 rb_erase(&entry->offset_index, &cluster->root);
                 BUG_ON(entry->bitmap);
+                try_merge_free_space(block_group, entry, false);
                 tree_insert_offset(&block_group->free_space_offset,
                                    entry->offset, &entry->offset_index, 0);
         }