On Thu, Nov 7, 2024 at 11:17 AM Joanne Koong <joannelkoong@xxxxxxxxx> wrote: > > For folios with mappings that have the AS_WRITEBACK_MAY_BLOCK flag set > on it, fail MIGRATE_SYNC mode migration with -EBUSY if the folio is > currently under writeback. If the AS_WRITEBACK_MAY_BLOCK flag is set on > the mapping, the writeback may take an indeterminate amount of time to > complete, so we cannot wait on writeback. Please ignore this patch (i meant to delete it from my local repo but forgot before submitting) - it is superseded by https://lore.kernel.org/linux-fsdevel/20241107191618.2011146-7-joannelkoong@xxxxxxxxx/T/#u, which is the same change but has a more correct commit message. The migration is skipped (see migrate_pages_batch() logic), not failed. Thanks, Joanne > > Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx> > --- > mm/migrate.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index df91248755e4..1d038a4202ae 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1260,7 +1260,10 @@ static int migrate_folio_unmap(new_folio_t get_new_folio, > */ > switch (mode) { > case MIGRATE_SYNC: > - break; > + if (!src->mapping || > + !mapping_writeback_may_block(src->mapping)) > + break; > + fallthrough; > default: > rc = -EBUSY; > goto out; > -- > 2.43.5 >
