On Mon, Aug 31, 2020 at 06:42:19PM +0100, Matthew Wilcox wrote:
> On Mon, Aug 31, 2020 at 01:25:34PM -0400, Qian Cai wrote:
> > + case IOMAP_DELALLOC:
> > + /*
> > + * DIO is not serialised against mmap() access at all, and so
> > + * if the page_mkwrite occurs between the writeback and the
> > + * iomap_apply() call in the DIO path, then it will see the
> > + * DELALLOC block that the page-mkwrite allocated.
> > + */
> > + path = file_path(dio->iocb->ki_filp, pathname,
> > + sizeof(pathname));
> > + if (IS_ERR(path))
> > + path = "(unknown)";
> > +
> > + pr_warn_ratelimited("Direct I/O collision with buffered writes! File: %s Comm: %.20s\n",
> > + path, current->comm);
>
> "File: %pD4"?
Sounds like a good idea. I could use that.
