On Tue, Aug 04 2020 at 8:47am -0400, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, Aug 04, 2020 at 07:33:05AM -0500, John Donnelly wrote: > > From: Mike Snitzer <snitzer@xxxxxxxxxx> > > > > Discontinue issuing writethrough write IO in series to the origin and > > then cache. > > > > Use bio_clone_fast() to create a new origin clone bio that will be > > mapped to the origin device and then bio_chain() it to the bio that gets > > remapped to the cache device. The origin clone bio does _not_ have a > > copy of the per_bio_data -- as such check_if_tick_bio_needed() will not > > be called. > > > > The cache bio (parent bio) will not complete until the origin bio has > > completed -- this fulfills bio_clone_fast()'s requirements as well as > > the requirement to not complete the original IO until the write IO has > > completed to both the origin and cache device. > > > > Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> > > > > (cherry picked from commit 2df3bae9a6543e90042291707b8db0cbfbae9ee9) > > > > Fixes: 4ec34f2196d125ff781170ddc6c3058c08ec5e73 (dm bio record: > > save/restore bi_end_io and bi_integrity ) > > > > 4ec34f21 introduced a mkfs.ext4 hang on a LVM device that has been > > modified with lvconvert --cachemode=writethrough. > > > > CC:stable@xxxxxxxxxxxxxxx for 4.14.y > > > > Signed-off-by: John Donnelly <john.p.donnelly@xxxxxxxxxx> > > Reviewed-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@xxxxxxxxxx> > > > > conflicts: > > drivers/md/dm-cache-target.c. - Corrected usage of > > writethrough_mode(&cache->feature) that was caught by > > compiler, and removed unused static functions : writethrough_endio(), > > defer_writethrough_bio(), wake_deferred_writethrough_worker() > > that generated warnings. > > What is this "conflicts nonsense"? You don't see that in any other > kernel patch changelog, do you? > > > --- > > drivers/md/dm-cache-target.c | 92 ++++++++++++++++++-------------------------- > > 1 file changed, 37 insertions(+), 55 deletions(-) > > Please fix your email client up, it's totally broken and this does not > work at all and is getting frustrating from my side here. > > Try sending emails to yourself and see if you can apply the patches, as > the one you sent here does not work, again: John's inability to submit a patch that can apply aside: I do not like how this patch header is constructed (yet attributed "From" me). It is devoid of detail as it relates to stable@. Greg, please don't apply the v4 of this patch either. I'll craft a proper stable@ patch that explains the reason for change and why we're left having to resolve conflicts in stable@. But first I need to focus on sending DM changes to Linus for v5.9 merge. Thanks, Mike
