On Wed, Feb 11, 2026 at 03:00:58PM -0500, Peter Xu wrote:
> On Sun, Feb 08, 2026 at 12:35:43PM +0200, Mike Rapoport wrote:
> > > > +static void shmem_mfill_filemap_remove(struct folio *folio,
> > > > + struct vm_area_struct *vma)
> > > > +{
> > > > + struct inode *inode = file_inode(vma->vm_file);
> > > > +
> > > > + filemap_remove_folio(folio);
> > > > + shmem_recalc_inode(inode, 0, 0);
> > > > folio_unlock(folio);
> > > > - folio_put(folio);
> > > > -out_unacct_blocks:
> > > > - shmem_inode_unacct_blocks(inode, 1);
> > >
> > > This looks wrong, or maybe I miss somewhere we did the unacct_blocks()?
> >
> > This is handled by shmem_recalc_inode(inode, 0, 0).
>
> IIUC shmem_recalc_inode() only does the fixup of shmem_inode_info over
> possiblly changing inode->i_mapping->nrpages. It's not for reverting the
> accounting in the failure paths here.
>
> OTOH, we still need to maintain accounting for the rest things with
> correctly invoke shmem_inode_unacct_blocks(). One thing we can try is
> testing this series against either shmem quota support (since 2023, IIUC
> it's relevant to "quota" mount option), or max_blocks accountings (IIUC,
> "size" mount option), etc. Any of those should reflect a difference if my
> understanding is correct.
>
> So IIUC we still need the unacct_blocks(), please kindly help double check.
I followed shmem_get_folio_gfp() error handling, and unless I missed
something we should have the same sequence with uffd.
In shmem_mfill_filemap_add() we increment both i_mapping->nrpages and
info->alloced in shmem_add_to_page_cache() and
shmem_recalc_inode(inode, 1, 0) respectively.
Then in shmem_filemap_remove() the call to filemap_remove_folio()
decrements i_mapping->nrpages and shmem_recalc_inode(inode, 0, 0) will see
freed=1 and will call shmem_inode_unacct_blocks().
> Thanks,
>
> --
> Peter Xu
>
--
Sincerely yours,
Mike.
