On Tue 10-11-20 23:12:14, Chengguang Xu wrote:
> ---- 在 星期二, 2020-11-10 21:45:51 Jan Kara <jack@xxxxxxx> 撰写 ----
> > On Sun 08-11-20 22:03:04, Chengguang Xu wrote:
> > > +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);
> > > +
> > > + iflag |= upper->i_state & I_DIRTY_ALL;
> > > +
> > > + if (mapping_writably_mapped(upper->i_mapping) ||
> > > + mapping_tagged(upper->i_mapping, PAGECACHE_TAG_WRITEBACK))
> > > + iflag |= I_DIRTY_PAGES;
> > > +
> > > + if (iflag)
> > > + ovl_mark_inode_dirty(inode);
> >
> > I think you didn't incorporate feedback we were speaking about in the last
> > version of the series. May comment in [1] still applies - you can miss
> > inodes dirtied through mmap when you decide to clean the inode here. So
> > IMHO you need something like:
> >
> > if (inode_is_open_for_write(inode))
> > ovl_mark_inode_dirty(inode);
> >
> > here to keep inode dirty while it is open for write (and not based on upper
> > inode state which is unreliable).
>
> Hi Jan,
>
> I not only checked upper inode state but also checked upper inode
> mmap(shared) state using mapping_writably_mapped(upper->i_mapping).
> Maybe it's better to move i_state check after mmap check but isn't above
> checks enough for mmapped file?
Ah, sorry, I'm blind! I missed the mapping_writably_mapped() check. Thanks
for explanation.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
