btrfs: do not require EXTENT_NOWAIT for btrfs_redirty_list_add()

The flag EXTENT_NOWAIT is a special flag to notify extent-io-tree code
that this operation should not sleep for the extent state preallocation.

However for btrfs_redirty_list_add(), all callers are able to sleep:

- clean_log_buffer()
  Just 2 lines before, we call btrfs_pin_reserved_extent(), which calls
  pin_down_extent(), and that function does not require EXTENT_NOWAIT.
  Thus we're safe to call it without EXTENT_NOWAIT.

- btrfs_free_tree_block()
  This function have several call sites which trigger tree read, e.g.
  walk_up_proc(), thus we're safe to call it without EXTENT_NOWAIT.

Thus there is no need to require EXTENT_NOWAIT flag.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/zoned.c

@@ -1609,7 +1609,7 @@ void btrfs_redirty_list_add(struct btrfs_transaction *trans,
 	set_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags);
 	set_extent_buffer_dirty(eb);
 	set_extent_bit(&trans->dirty_pages, eb->start, eb->start + eb->len - 1,
-			EXTENT_DIRTY | EXTENT_NOWAIT, NULL);
+			EXTENT_DIRTY, NULL);
 }
 
 bool btrfs_use_zone_append(struct btrfs_bio *bbio)