---- 在 星期日, 2020-11-08 22:03:06 Chengguang Xu <cgxu519@xxxxxxxxxxxx> 撰写 ----
> Introduce a helper ovl_wait_wb_inodes() to wait until all
> target upper inodes finish writeback.
>
> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxxxx>
> ---
> fs/overlayfs/super.c | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index e5607a908d82..9a535fc11221 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -255,6 +255,36 @@ static void ovl_put_super(struct super_block *sb)
> ovl_free_fs(ofs);
> }
>
> +void ovl_wait_wb_inodes(struct ovl_fs *ofs)
> +{
> + LIST_HEAD(tmp_list);
> + struct ovl_inode *oi;
> + struct inode *upper;
> +
> + spin_lock(&ofs->syncfs_wait_list_lock);
> + list_splice_init(&ofs->syncfs_wait_list, &tmp_list);
> +
> + while (!list_empty(&tmp_list)) {
> + oi = list_first_entry(&tmp_list, struct ovl_inode, wait_list);
> + list_del_init(&oi->wait_list);
> + ihold(&oi->vfs_inode);
Maybe I overlooked race condition with inode eviction, so still need to introduce
OVL_EVICT_PENDING flag just like we did in old syncfs efficiency patch series.
Thanks，
Chengguang
