Re: [PATCH 7/8] Btrfs: use REQ_CGROUP_PUNT for worker thread submitted bios

David Sterba
2019-06-14T15:14:42Z

On Thu, Jun 13, 2019 at 05:33:49PM -0700, Tejun Heo wrote:
> @@ -1251,12 +1258,29 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page,
> * to unlock it.
> */
> if (locked_page) {
> + /*
> + * Depending on the compressibility, the pages
> + * might or might not go through async. We want
> + * all of them to be accounted against @wbc once.
> + * Let's do it here before the paths diverge. wbc
> + * accounting is used only for foreign writeback
> + * detection and doesn't need full accuracy. Just
> + * account the whole thing against the first page.
> + */
> + wbc_account_io(wbc, locked_page, cur_end - start);
> async_chunk[i].locked_page = locked_page;
> locked_page = NULL;
> } else {
> async_chunk[i].locked_page = NULL;
> }
>
> + if (blkcg_css != blkcg_root_css) {
> + css_get(blkcg_css);

fs/btrfs/inode.c: In function ‘cow_file_range_async’:
fs/btrfs/inode.c:1278:4: error: implicit declaration of function ‘css_get’; did you mean ‘css_put’? [-Werror=implicit-function-declaration]
1278 | css_get(blkcg_css);
| ^~~~~~~
| css_put

I don't have CONFIG_CGROUPS enabled in the testing kernel so this probably
needs a wrapper so the ifdef is not in the middle of the function.