On Mon, Apr 29, 2024 at 08:19:31PM +0000, Steven French wrote:
> Wouldn't this make it harder to fix the regression when swap file support was temporarily removed from cifs.ko (due to the folio migration)? I was hoping to come back to fixing swapfile support for cifs.ko in 6.10-rc (which used to pass the various xfstests for this but code got removed with folios/netfs changes).
It was neither the folio conversion nor the netfs conversion which
removed the claim of swap support from cifs, but NeilBrown's
introduction of ->swap_rw. In commit e1209d3a7a67 he claims that
Only two filesystems set SWP_FS_OPS:
- cifs sets the flag, but ->direct_IO always fails so swap cannot work.
- nfs sets the flag, but ->direct_IO calls generic_write_checks()
which has failed on swap files for several releases.
As I recall the xfstests only checked that swapon/swapoff works; they
don't actually test that writing to swap and reading back from it work.
