On Wed, 18 Oct 2023 at 13:57, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>
> On Wed, Oct 18, 2023 at 09:25:18AM -0300, Wedson Almeida Filho wrote:
> > + fn read_folio(inode: &INode<Self>, mut folio: LockedFolio<'_>) -> Result {
> > + let pos = u64::try_from(folio.pos()).unwrap_or(u64::MAX);
> > + let size = u64::try_from(inode.size())?;
> > + let sb = inode.super_block();
> > +
> > + let copied = if pos >= size {
> > + 0
> > + } else {
> > + let offset = inode.data().offset.checked_add(pos).ok_or(ERANGE)?;
> > + let len = core::cmp::min(size - pos, folio.size().try_into()?);
> > + let mut foffset = 0;
> > +
> > + if offset.checked_add(len).ok_or(ERANGE)? > sb.data().data_size {
> > + return Err(EIO);
> > + }
> > +
> > + for v in sb.read(offset, len)? {
> > + let v = v?;
> > + folio.write(foffset, v.data())?;
> > + foffset += v.data().len();
> > + }
> > + foffset
> > + };
> > +
> > + folio.zero_out(copied, folio.size() - copied)?;
> > + folio.mark_uptodate();
> > + folio.flush_dcache();
> > +
> > + Ok(())
> > + }
>
> Who unlocks the folio here?
The `Drop` implementation of `LockedFolio`.
Note that `read_folio` is given ownership of `folio` (the last
argument), so when it goes out of scope (or when it's explicitly
dropped) its `drop` function is called automatically. You'll its
implementation (and the call to `folio_unlock`) in patch 9.
