mballoc: add comments to ext4_mb_mark_free_simple()
This patch adds comments to ext4_mb_mark_free_simple to make it more
understandable.
Signed-off-by: Coly Li <bosong.ly@taobao.com>
Cc: Alex Tomas <alex@clusterfs.com>
Cc: Theodore Tso <tytso@google.com>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 7de0e28..b5235c8 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -635,7 +635,12 @@
#define mb_check_buddy(e4b)
#endif
-/* FIXME!! need more doc */
+/*
+ * Divide blocks started from @first with length @len into
+ * smaller chunks with power of 2 blocks.
+ * Clear the bits in bitmap which the blocks of the chunk(s) covered,
+ * then increase bb_counters[] for corresponded chunk size.
+ */
static void ext4_mb_mark_free_simple(struct super_block *sb,
void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
struct ext4_group_info *grp)