On Thu, 23 Sept 2021 at 15:08, Chengguang Xu <cgxu519@xxxxxxxxxxxx> wrote:
>
> Implement overlayfs' ->write_inode to sync dirty data
> and redirty overlayfs' inode if necessary.
>
> 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 2ab77adf7256..cddae3ca2fa5 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -412,12 +412,42 @@ static void ovl_evict_inode(struct inode *inode)
> clear_inode(inode);
> }
>
> +static int ovl_write_inode(struct inode *inode,
> + struct writeback_control *wbc)
> +{
> + struct ovl_fs *ofs = inode->i_sb->s_fs_info;
> + struct inode *upper = ovl_inode_upper(inode);
> + unsigned long iflag = 0;
> + int ret = 0;
> +
> + if (!upper)
> + return 0;
> +
> + if (!ovl_should_sync(ofs))
> + return 0;
> +
> + if (upper->i_sb->s_op->write_inode)
> + ret = upper->i_sb->s_op->write_inode(inode, wbc);
Where is page writeback on upper inode triggered?
Thanks,
Miklos
