On Thu, Mar 03, 2022 at 08:25:50PM -0800, Hugh Dickins wrote: > filemap_unaccount_folio() has a WARN_ON_ONCE(folio_test_dirty(folio)). > It is good to warn of late dirtying on a persistent filesystem, but late > dirtying on tmpfs can only lose data which is expected to be thrown away; > and it's a pity if that warning comes ONCE on tmpfs, then hides others > which really matter. Make it conditional on mapping_cap_writeback(). > > Cleanup: then folio_account_cleaned() no longer needs to check that > for itself, and so no longer needs to know the mapping. At first blush, I like this a lot. Will look more in the morning.