Re: [PATCH] btrfs: fix inline reflink deadlock at non-zero offset

[Guangshuo Li]

Hi Filipe,

On Wed, 3 Jun 2026 at 20:36, Filipe Manana <fdmanana@xxxxxxxxxx> wrote:
>
> On Wed, Jun 3, 2026 at 1:25 PM Guangshuo Li <lgs201920130244@xxxxxxxxx> wrote:
> >
> > clone_copy_inline_extent() can copy an inline extent into a page of the
> > destination inode before starting a transaction. If that page is beyond
> > EOF, writeback started by a transaction commit with flushoncommit can
> > invalidate the folio and block on the same extent range lock held by the
> > reflink task, while the reflink task waits to start a transaction.
> >
> > The copy_to_page path already updates i_size after copy_inline_to_page(),
> > so writeback no longer treats the copied page as beyond EOF. However,
> > clone_copy_inline_extent() has an earlier new_key->offset > 0 path that
> > also calls copy_inline_to_page() and then goes to out, where it starts a
> > transaction. That path still leaves i_size unchanged before starting the
> > transaction.
> >
> > Update i_size after a successful copy_inline_to_page() in the early
> > non-zero offset path as well, matching the existing copy_to_page path.
> >
> > Fixes: 05a5a7621ce66 ("Btrfs: implement full reflink support for inline extents")
> > Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
>
> Again?
>
> You already sent this patch yesterday, and there's a reply:
>
> https://lore.kernel.org/linux-btrfs/20260603120443.1394044-1-lgs201920130244@xxxxxxxxx/
>
> > ---
> >  fs/btrfs/reflink.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
> > index 49865a463780..5722cccb53eb 100644
> > --- a/fs/btrfs/reflink.c
> > +++ b/fs/btrfs/reflink.c
> > @@ -185,6 +185,8 @@ static int clone_copy_inline_extent(struct btrfs_inode *inode,
> >         if (new_key->offset > 0) {
> >                 ret = copy_inline_to_page(inode, new_key->offset,
> >                                           inline_data, size, datal, comp_type);
> > +               if (ret == 0 && new_key->offset + datal > i_size_read(&inode->vfs_inode))
> > +                       i_size_write(&inode->vfs_inode, new_key->offset + datal);
> >                 goto out;
> >         }
> >
> > --
> > 2.43.0
> >
> >
Sorry, this was my mistake. I accidentally sent the same patch again.

Sorry for the noise.

Thanks,
Guangshuo