[Devel] [RFC PATCH vz9] dm-ploop: port the standby mode feature.
Alexander Atanasov
alexander.atanasov at virtuozzo.com
Thu Oct 20 13:51:03 MSK 2022
Based on commit bdadef81aba5 ("ploop: add a standby mode") and
commit f5df00558e64 ("ploop: move to standby mode after fsync() error too").
Extend to only perform standby check when enabled on the target.
Add static key enabled via module parameter when running on
mixed mode systems and standby enable flag on the request queue.
Using the flags perform the check only if required by
the target device. Avoid unwanted side effects and performance impact.
Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
drivers/md/dm-ploop-map.c | 36 +++++++++++++++++++++++++++++++++++-
drivers/md/dm-ploop-target.c | 22 +++++++++++++++++++++-
drivers/md/dm-ploop.h | 1 +
include/linux/blkdev.h | 4 ++++
4 files changed, 61 insertions(+), 2 deletions(-)
Cc: Kui Liu <Kui.Liu at acronis.com>
Cc: Alexey Kuznetsov <kuznet at acronis.com>
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index e8288e522e28..46d7811b3c8e 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -19,6 +19,7 @@
#include <uapi/linux/falloc.h>
#include "dm-ploop.h"
#include "dm-rq.h"
+#include "dm-core.h"
#define PREALLOC_SIZE (128ULL * 1024 * 1024)
@@ -28,6 +29,8 @@ static void ploop_prq_endio(struct pio *pio, void *prq_ptr,
#define DM_MSG_PREFIX "ploop"
+DEFINE_STATIC_KEY_FALSE(ploop_standby_check);
+
static unsigned int ploop_pio_nr_segs(struct pio *pio)
{
struct bvec_iter bi = {
@@ -1163,6 +1166,26 @@ static void ploop_queue_resubmit(struct pio *pio)
queue_work(ploop->wq, &ploop->worker);
}
+static void ploop_check_standby_mode(struct ploop *ploop, long res)
+{
+ struct request_queue *q = ploop_blk_queue(ploop);
+ int prev;
+
+ if (!blk_queue_standby_en(q))
+ return;
+
+ /* move to standby if delta lease was stolen or mount is gone */
+ if (res != -EBUSY && res != -ENOTCONN && res != -EIO)
+ return;
+
+ spin_lock_irq(&q->queue_lock);
+ prev = blk_queue_flag_test_and_set(QUEUE_FLAG_STANDBY, q);
+ spin_unlock_irq(&q->queue_lock);
+
+ if (!prev)
+ pr_info("ploop: switch into standby mode\n");
+}
+
static void ploop_data_rw_complete(struct pio *pio)
{
bool completed;
@@ -1175,6 +1198,8 @@ static void ploop_data_rw_complete(struct pio *pio)
ploop_queue_resubmit(pio);
return;
}
+ if (static_branch_unlikely(&ploop_standby_check))
+ ploop_check_standby_mode(pio->ploop, pio->ret);
pio->bi_status = errno_to_blk_status(pio->ret);
}
@@ -1815,8 +1840,11 @@ void do_ploop_fsync_work(struct work_struct *ws)
ret = vfs_fsync(file, 0);
while ((pio = ploop_pio_list_pop(&flush_pios)) != NULL) {
- if (unlikely(ret))
+ if (unlikely(ret)) {
pio->bi_status = errno_to_blk_status(ret);
+ if (static_branch_unlikely(&ploop_standby_check))
+ ploop_check_standby_mode(ploop, ret);
+ }
ploop_pio_endio(pio);
}
}
@@ -1869,6 +1897,12 @@ int ploop_clone_and_map(struct dm_target *ti, struct request *rq,
struct ploop_rq *prq;
struct pio *pio;
+
+ if (static_branch_unlikely(&ploop_standby_check)) {
+ if (blk_queue_standby(ploop_blk_queue(ploop)))
+ return DM_MAPIO_KILL;
+ }
+
if (blk_rq_bytes(rq) && ploop_rq_valid(ploop, rq) < 0)
return DM_MAPIO_KILL;
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 4f7dc36eee0c..03cbf7a3b22c 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -21,17 +21,24 @@
#include <linux/uio.h>
#include <linux/error-injection.h>
#include "dm-ploop.h"
+#include "dm-core.h"
#define DM_MSG_PREFIX "ploop"
bool ignore_signature_disk_in_use = false; /* For development purposes */
module_param(ignore_signature_disk_in_use, bool, 0444);
MODULE_PARM_DESC(ignore_signature_disk_in_use,
- "Does not check for SIGNATURE_DISK_IN_USE");
+ "Does not check for SIGNATURE_DISK_IN_USE");
+
+bool ploop_enable_standby; /* Used when running on specific targets */
+module_param(ploop_enable_standby, bool, 0444);
+MODULE_PARM_DESC(ploop_enable_standby,
+ "Enable blk queue standby mode checks");
static struct kmem_cache *prq_cache;
static struct kmem_cache *pio_cache;
struct kmem_cache *cow_cache;
+extern struct static_key ploop_standby_check;
static void ploop_aio_do_completion(struct pio *pio)
{
@@ -406,6 +413,14 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
ti->private = ploop;
ploop->ti = ti;
+ if (blk_queue_standby_en(ploop_blk_queue(ploop))) {
+ blk_queue_flag_clear(QUEUE_FLAG_STANDBY, ploop_blk_queue(ploop));
+ if (!static_key_enabled(&ploop_standby_check)) {
+ static_key_enable(&ploop_standby_check);
+ pr_info("ploop: standby mode check enabled\n");
+ }
+ }
+
if (kstrtou32(argv[0], 10, &ploop->cluster_log) < 0) {
ret = -EINVAL;
ti->error = "could not parse cluster_log";
@@ -604,6 +619,11 @@ static int __init dm_ploop_init(void)
if (!prq_cache || !pio_cache || !cow_cache)
goto err;
+ if (ploop_enable_standby) {
+ static_key_enable(&ploop_standby_check);
+ pr_info("ploop: standby mode check enabled\n");
+ }
+
r = dm_register_target(&ploop_target);
if (r) {
DMERR("ploop target registration failed: %d", r);
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index 5d953278a976..f7c21b0b1597 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -230,6 +230,7 @@ struct ploop {
struct timer_list enospc_timer;
bool event_enospc;
};
+#define ploop_blk_queue(p) ((p)->ti->table->md->queue)
struct ploop_rq {
struct request *rq;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8fcd753c70b0..bafe008245c0 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -434,6 +434,8 @@ struct request_queue {
#define QUEUE_FLAG_RQ_ALLOC_TIME 27 /* record rq->alloc_time_ns */
#define QUEUE_FLAG_HCTX_ACTIVE 28 /* at least one blk-mq hctx is active */
#define QUEUE_FLAG_NOWAIT 29 /* device supports NOWAIT */
+#define QUEUE_FLAG_STANDBY 30 /* unable to handle read/write requests */
+#define QUEUE_FLAG_STANDBY_EN 31 /* enable standby queue flag */
#define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_SAME_COMP) | \
@@ -480,6 +482,8 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
#define blk_queue_fua(q) test_bit(QUEUE_FLAG_FUA, &(q)->queue_flags)
#define blk_queue_registered(q) test_bit(QUEUE_FLAG_REGISTERED, &(q)->queue_flags)
#define blk_queue_nowait(q) test_bit(QUEUE_FLAG_NOWAIT, &(q)->queue_flags)
+#define blk_queue_standby(q) test_bit(QUEUE_FLAG_STANDBY, &(q)->queue_flags)
+#define blk_queue_standby_en(q) test_bit(QUEUE_FLAG_STANDBY_EN, &(q)->queue_flags)
extern void blk_set_pm_only(struct request_queue *q);
extern void blk_clear_pm_only(struct request_queue *q);
base-commit: d2a62a0d23aff88721eb146b6612e2ae70e6a6b3
--
2.31.1
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