---- 在 星期五, 2021-11-26 17:10:07 Jan Kara <jack@xxxxxxx> 撰写 ----
> On Mon 22-11-21 11:00:33, Chengguang Xu wrote:
> > From: Chengguang Xu <charliecgxu@xxxxxxxxxxx>
> >
> > We simply mark overlayfs inode dirty when it has upper,
> > it's much simpler than mark dirtiness on modification.
> >
> > Signed-off-by: Chengguang Xu <charliecgxu@xxxxxxxxxxx>
> > ---
> > fs/overlayfs/inode.c | 4 +++-
> > fs/overlayfs/util.c | 1 +
> > 2 files changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> > index 1f36158c7dbe..027ffc0a2539 100644
> > --- a/fs/overlayfs/inode.c
> > +++ b/fs/overlayfs/inode.c
> > @@ -778,8 +778,10 @@ void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
> > {
> > struct inode *realinode;
> >
> > - if (oip->upperdentry)
> > + if (oip->upperdentry) {
> > OVL_I(inode)->__upperdentry = oip->upperdentry;
> > + mark_inode_dirty(inode);
> > + }
> > if (oip->lowerpath && oip->lowerpath->dentry)
> > OVL_I(inode)->lower = igrab(d_inode(oip->lowerpath->dentry));
> > if (oip->lowerdata)
>
> Hum, does this get called only for inodes with upper inode existing? I
> suppose we do not need to track inodes that were not copied up because they
> cannot be dirty? I'm sorry, my knowledge of overlayfs is rather limited so
> I may be missing something basic.
>
Well, as long as overly inode has upper it can be modified without copy-up,
so we need to track all overlay inodes which have upper inode.
Thanks,
Chengguang
