The commit is pushed to "branch-rh9-5.14.0-427.44.1.vz9.80.x-ovz" and will
appear at g...@bitbucket.org:openvz/vzkernel.git
after rh9-5.14.0-427.44.1.vz9.80.6
------>
commit 4b922f2e6f8217ed03051e0ab79c530c1c615b3c
Author: Alexander Atanasov <alexander.atana...@virtuozzo.com>
Date: Fri Jan 24 17:36:26 2025 +0200
dm-ploop: fix locking and improve error handling when submitting pios
The difference between hlist_unhashed_lockless and hlist_unhashed
is that _lockless version uses READ_ONCE to do the check.
Since it is used without locks we must switch to the _lockless variant.
Also make locking clusters and adding to inflight_pios return result
so we can track if they failed and where.
https://virtuozzo.atlassian.net/browse/VSTOR-91821
Signed-off-by: Alexander Atanasov <alexander.atana...@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 | 70 ++++++++++++++++++++++++++++++++++++-----------
1 file changed, 54 insertions(+), 16 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 3b24778e0894..dc150c8050d9 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -498,17 +498,32 @@ static void ploop_dec_nr_inflight(struct ploop *ploop,
struct pio *pio)
}
}
-static void ploop_link_pio(struct hlist_head head[], struct pio *pio,
+static int ploop_link_pio(struct hlist_head head[], struct pio *pio,
u32 clu, bool exclusive)
{
struct hlist_head *slot = ploop_htable_slot(head, clu);
+ struct ploop *ploop = pio->ploop;
+
+ if (exclusive) {
+ struct pio *pe = ploop_find_pio(head, clu);
+
+ if (pe == pio)
+ return 1;
- if (exclusive)
- WARN_ON_ONCE(ploop_find_pio(head, clu) != NULL);
+ WARN_ON_ONCE(pe != NULL);
- BUG_ON(!hlist_unhashed(&pio->hlist_node));
+ if (pe)
+ PL_ERR("clu:%u already exclusively locked\n", clu);
+ }
+
+ if (!hlist_unhashed_lockless(&pio->hlist_node)) {
+ PL_ERR("already hashed clu:%u e:%d\n", clu, exclusive);
+ WARN_ON_ONCE(1);
+ return 0;
+ }
hlist_add_head(&pio->hlist_node, slot);
pio->clu = clu;
+ return 1;
}
/*
@@ -516,45 +531,55 @@ static void ploop_link_pio(struct hlist_head head[],
struct pio *pio,
* or from exclusive_bios_rbtree. BIOs from endio_list are requeued
* to deferred_list.
*/
-static void ploop_unlink_pio(struct ploop *ploop, struct pio *pio,
+static int ploop_unlink_pio(struct ploop *ploop, struct pio *pio,
struct list_head *pio_list)
{
- BUG_ON(hlist_unhashed(&pio->hlist_node));
+ if (hlist_unhashed_lockless(&pio->hlist_node)) {
+ WARN_ON_ONCE(1);
+ return 0;
+ }
hlist_del_init(&pio->hlist_node);
list_splice_tail_init(&pio->endio_list, pio_list);
+ return 1;
}
-static void ploop_add_cluster_lk(struct ploop *ploop, struct pio *pio, u32 clu)
+static int ploop_add_cluster_lk(struct ploop *ploop, struct pio *pio, u32 clu)
{
unsigned long flags;
+ int ret;
spin_lock_irqsave(&ploop->deferred_lock, flags);
- ploop_link_pio(ploop->exclusive_pios, pio, clu, true);
+ ret = ploop_link_pio(ploop->exclusive_pios, pio, clu, true);
spin_unlock_irqrestore(&ploop->deferred_lock, flags);
+ return ret;
}
-static void ploop_del_cluster_lk(struct ploop *ploop, struct pio *pio)
+static int ploop_del_cluster_lk(struct ploop *ploop, struct pio *pio)
{
LIST_HEAD(pio_list);
unsigned long flags;
+ int ret;
spin_lock_irqsave(&ploop->deferred_lock, flags);
- ploop_unlink_pio(ploop, pio, &pio_list);
+ ret = ploop_unlink_pio(ploop, pio, &pio_list);
spin_unlock_irqrestore(&ploop->deferred_lock, flags);
if (!list_empty(&pio_list))
ploop_dispatch_pios(ploop, NULL, &pio_list);
+ return ret;
}
-static void ploop_link_submitting_pio(struct ploop *ploop, struct pio *pio,
+static int ploop_link_submitting_pio(struct ploop *ploop, struct pio *pio,
u32 clu)
{
unsigned long flags;
+ int ret;
spin_lock_irqsave(&ploop->inflight_lock, flags);
- ploop_link_pio(ploop->inflight_pios, pio, clu, false);
+ ret = ploop_link_pio(ploop->inflight_pios, pio, clu, false);
spin_unlock_irqrestore(&ploop->inflight_lock, flags);
+ return ret;
}
static void ploop_unlink_completed_pio(struct ploop *ploop, struct pio *pio)
@@ -562,7 +587,7 @@ static void ploop_unlink_completed_pio(struct ploop *ploop,
struct pio *pio)
LIST_HEAD(pio_list);
unsigned long flags;
- if (hlist_unhashed(&pio->hlist_node))
+ if (hlist_unhashed_lockless(&pio->hlist_node))
return;
spin_lock_irqsave(&ploop->inflight_lock, flags);
@@ -706,7 +731,8 @@ static int ploop_handle_discard_pio(struct ploop *ploop,
struct pio *pio,
return 0;
}
- ploop_add_cluster_lk(ploop, pio, clu);
+ if (!ploop_add_cluster_lk(ploop, pio, clu))
+ PL_ERR("dis clu %d already locked\n", clu);
pio->wants_discard_index_cleanup = true;
punch_hole:
@@ -1429,7 +1455,8 @@ static int ploop_submit_cluster_cow(struct ploop *ploop,
unsigned int level,
cow->aux_pio = aux_pio;
cow->cow_pio = cow_pio;
- ploop_add_cluster_lk(ploop, cow_pio, clu);
+ if (!ploop_add_cluster_lk(ploop, cow_pio, clu))
+ PL_ERR("cowclu %d already locked\n", clu);
/* Stage #0: read secondary delta full clu */
ploop_map_and_submit_rw(ploop, dst_clu, aux_pio, level);
@@ -1706,8 +1733,19 @@ static int ploop_process_one_deferred_bio(struct ploop
*ploop, struct pio *pio)
&dst_clu, pio);
if (!ret)
goto executed;
+
queue: /* pio needs to go to the queue */
- ploop_link_submitting_pio(ploop, pio, clu);
+ if (!ploop_link_submitting_pio(ploop, pio, clu)) {
+ PL_ERR("link submitting pio failed\n");
+ /* Pio is put into endio_list */
+ if (ploop_postpone_if_cluster_locked(ploop, pio, clu)) {
+ goto handled;
+ } else {
+ PL_ERR("link submitting pio postpone failed\n");
+ WARN_ON_ONCE(1);
+ /* fail thru and run it anyway nothing */
+ }
+ }
ploop_map_and_submit_rw(ploop, dst_clu, pio, ploop_top_level(ploop));
// return 1;
executed: /* pio op started */
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