[Devel] [PATCH vz9 v2 16/65] dm-ploop: set IOCB_DSYNC on all FUA requests

[Konstantin Khorenko]

From: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>

When mapping request, save all flags, rather then only operation
type. Use it later to check if the request is FUA or not.
Unfortunately there is no REQ_FUA equivalent on IOCB layer, but
IOCB_DSYNC is usually translated to it, as can be seen in
__iomap_dio_rw().

https://virtuozzo.atlassian.net/browse/VSTOR-91817
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>

======
Patchset description:
ploop: optimistations and scalling

Ploop processes requsts in a different threads in parallel
where possible which results in significant improvement in
performance and makes further optimistations possible.

Known bugs:
  - delayed metadata writeback is not working and is missing error handling
     - patch to disable it until fixed
  - fast path is not working - causes rcu lockups - patch to disable it

Further improvements:
  - optimize md pages lookups

Alexander Atanasov (50):
  dm-ploop: md_pages map all pages at creation time
  dm-ploop: Use READ_ONCE/WRITE_ONCE to access md page data
  dm-ploop: fsync after all pios are sent
  dm-ploop: move md status to use proper bitops
  dm-ploop: convert wait_list and wb_batch_llist to use lockless lists
  dm-ploop: convert enospc handling to use lockless lists
  dm-ploop: convert suspended_pios list to use lockless list
  dm-ploop: convert the rest of the lists to use llist variant
  dm-ploop: combine processing of pios thru prepare list and remove
    fsync worker
  dm-ploop: move from wq to kthread
  dm-ploop: move preparations of pios into the caller from worker
  dm-ploop: fast path execution for reads
  dm-ploop: do not use a wrapper for set_bit to make a page writeback
  dm-ploop: BAT use only one list for writeback
  dm-ploop: make md writeback timeout to be per page
  dm-ploop: add interface to disable bat writeback delay
  dm-ploop: convert wb_batch_list to lockless variant
  dm-ploop: convert high_prio to status
  dm-ploop: split cow processing into two functions
  dm-ploop: convert md page rw lock to spin lock
  dm-ploop: convert bat_rwlock to bat_lock spinlock
  dm-ploop: prepare bat updates under bat_lock
  dm-ploop: make ploop_bat_write_complete ready for parallel pio
    completion
  dm-ploop: make ploop_submit_metadata_writeback return number of
    requests sent
  dm-ploop: introduce pio runner threads
  dm-ploop: add pio list ids to be used when passing pios to runners
  dm-ploop: process pios via runners
  dm-ploop: disable metadata writeback delay
  dm-ploop: disable fast path
  dm-ploop: use lockless lists for chained cow updates list
  dm-ploop: use lockless lists for data ready pios
  dm-ploop: give runner threads better name
  dm-ploop: resize operation - add holes bitmap locking
  dm-ploop: remove unnecessary operations
  dm-ploop: use filp per thread
  dm-ploop: catch if we try to advance pio past bio end
  dm-ploop: support REQ_FUA for data pios
  dm-ploop: proplerly access nr_bat_entries
  dm-ploop: fix locking and improve error handling when submitting pios
  dm-ploop: fix how ENOTBLK is handled
  dm-ploop: sync when suspended or stopping
  dm-ploop: rework bat completion logic
  dm-ploop: rework logic in pio processing
  dm-ploop: end fsync pios in parallel
  dm-ploop: make filespace preallocations async
  dm-ploop: resubmit enospc pios from dispatcher thread
  dm-ploop: dm-ploop: simplify discard completion
  dm-ploop: use GFP_ATOMIC instead of GFP_NOIO
  dm-ploop: fix locks used in mixed context
  dm-ploop: fix how current flags are managed inside threads

Andrey Zhadchenko (13):
  dm-ploop: do not flush after metadata writes
  dm-ploop: set IOCB_DSYNC on all FUA requests
  dm-ploop: remove extra ploop_cluster_is_in_top_delta()
  dm-ploop: introduce per-md page locking
  dm-ploop: reduce BAT accesses on discard completion
  dm-ploop: simplify llseek
  dm-ploop: speed up ploop_prepare_bat_update()
  dm-ploop: make new allocations immediately visible in BAT
  dm-ploop: drop ploop_cluster_is_in_top_delta()
  dm-ploop: do not wait for BAT update for non-FUA requests
  dm-ploop: add delay for metadata writeback
  dm-ploop: submit all postponed metadata on REQ_OP_FLUSH
  dm-ploop: handle REQ_PREFLUSH

Feature: dm-ploop: ploop target driver
---
 drivers/md/dm-ploop-map.c    | 13 ++++++++++---
 drivers/md/dm-ploop-target.c |  2 ++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index c8c0f7c76cb3..7e4f4a31e166 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -133,7 +133,7 @@ static void ploop_init_prq_and_embedded_pio(struct ploop *ploop,
 		struct request *rq, struct ploop_rq *prq, struct pio *pio)
 {
 	ploop_init_prq(prq, rq);
-	ploop_init_pio(ploop, req_op(rq), pio);
+	ploop_init_pio(ploop, rq->cmd_flags, pio);
 	pio->css = prq->css;
 
 	pio->endio_cb = ploop_prq_endio;
@@ -279,7 +279,11 @@ static struct pio *ploop_split_and_chain_pio(struct ploop *ploop,
 	if (!split)
 		return NULL;
 
-	ploop_init_pio(ploop, pio->bi_op, split);
+	/*
+	 * Do not copy REQ_FUA to every split pio. we will sync
+	 * before calling endio on original pio.
+	 */
+	ploop_init_pio(ploop, pio->bi_op & ~REQ_FUA, split);
 	split->css = pio->css;
 	split->queue_list_id = pio->queue_list_id;
 	split->free_on_endio = true;
@@ -1496,6 +1500,9 @@ static bool ploop_locate_new_cluster_and_attach_pio(struct ploop *ploop,
 	if (bat_update_prepared)
 		ploop_md_make_dirty(ploop, md);
 
+	if (pio->bi_op & REQ_FUA)
+		piwb->pio->bi_op |= REQ_FUA;
+
 	ploop_attach_end_action(pio, piwb);
 	attached = true;
 out:
@@ -1912,7 +1919,7 @@ static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
 	if (blk_rq_bytes(rq)) {
 		pio->queue_list_id = PLOOP_LIST_PREPARE;
 	} else {
-		WARN_ON_ONCE(pio->bi_op != REQ_OP_FLUSH);
+		WARN_ON_ONCE(!((pio->bi_op & REQ_OP_MASK) == REQ_OP_FLUSH));
 		pio->queue_list_id = PLOOP_LIST_FLUSH;
 	}
 
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 589082c8e110..00d160b3fd3c 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -61,6 +61,8 @@ void ploop_call_rw_iter(struct file *file, loff_t pos, unsigned rw,
 	init_sync_kiocb(iocb, file);
 	iocb->ki_pos = pos;
 	iocb->ki_complete = ploop_aio_complete;
+	if (pio->bi_op & REQ_FUA)
+		iocb->ki_flags |= IOCB_DSYNC;
 
 	atomic_set(&pio->aio_ref, 2);
 
-- 
2.43.5