On Mon, Aug 03, 2020 at 12:27:31PM -0500, John Donnelly wrote:
From: Mike Snitzer snitzer@redhat.com
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@redhat.com
(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@vger.kernel.org for 4.14.y
Signed-off-by: John Donnelly john.p.donnelly@oracle.com Reviewed-by: Somasundaram Krishnasamy somasundaram.krishnasamy@oracle.com
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.
drivers/md/dm-cache-target.c | 92 ++++++++++++++++++-------------------------- 1 file changed, 37 insertions(+), 55 deletions(-)
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 69cdb29ef6be..2732d1df05fa 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -450,6 +450,7 @@ struct cache { struct work_struct migration_worker; struct delayed_work waker; struct dm_bio_prison_v2 *prison;
- struct bio_set *bs; mempool_t *migration_pool;
@@ -537,11 +538,6 @@ static void wake_deferred_bio_worker(struct cache *cache)
Line-wrapped and unable to apply :(