Btrfs: use flag EXTENT_DEFRAG for snapshot-aware defrag
We're going to use this flag EXTENT_DEFRAG to indicate which range
belongs to defragment so that we can implement snapshow-aware defrag:
We set the EXTENT_DEFRAG flag when dirtying the extents that need
defragmented, so later on writeback thread can differentiate between
normal writeback and writeback started by defragmentation.
Original-Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 19319f5..4a41b17 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1144,6 +1144,14 @@
NULL, cached_state, mask);
}
+int set_extent_defrag(struct extent_io_tree *tree, u64 start, u64 end,
+ struct extent_state **cached_state, gfp_t mask)
+{
+ return set_extent_bit(tree, start, end,
+ EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
+ NULL, cached_state, mask);
+}
+
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
gfp_t mask)
{