[Devel] [PATCH rh7 3/4] ploop: wire push_backup into state-machine
Maxim Patlasov
mpatlasov at virtuozzo.com
Fri Apr 29 20:20:25 PDT 2016
When ploop state-machine looks at preq first time, it suspends the preq if
its cluster-block matches pbd->ppb_map -- the copy of CBT mask initially.
To suspend preq we simply put it to pbd->pending_tree and plo->lockout_tree.
Later, when userspace reports that out-of-band processing is done, we
set PLOOP_REQ_PUSH_BACKUP bit in preq->state, re-schedule the preq and
wakeup ploop state-machine. This PLOOP_REQ_PUSH_BACKUP bit lets state-machine
know that given preq is OK and we shouldn't suspend further preq-s for
given cluster-block anymore.
Signed-off-by: Maxim Patlasov <mpatlasov at virtuozzo.com>
---
drivers/block/ploop/dev.c | 32 +++++++++++++++++++
drivers/block/ploop/push_backup.c | 62 +++++++++++++++++++++++++++++++++++++
drivers/block/ploop/push_backup.h | 6 ++++
include/linux/ploop/ploop.h | 1 +
4 files changed, 101 insertions(+)
diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
index 2a77d2e..c7cc385 100644
--- a/drivers/block/ploop/dev.c
+++ b/drivers/block/ploop/dev.c
@@ -2021,6 +2021,38 @@ restart:
return;
}
+ /* push_backup special processing */
+ if (!test_bit(PLOOP_REQ_LOCKOUT, &preq->state) &&
+ (preq->req_rw & REQ_WRITE) && preq->req_size &&
+ ploop_pb_check_bit(plo->pbd, preq->req_cluster)) {
+ if (ploop_pb_preq_add_pending(plo->pbd, preq)) {
+ /* already reported by userspace push_backup */
+ ploop_pb_clear_bit(plo->pbd, preq->req_cluster);
+ } else {
+ spin_lock_irq(&plo->lock);
+ ploop_add_lockout(preq, 0);
+ spin_unlock_irq(&plo->lock);
+ /*
+ * preq IN: preq is in ppb_pending tree waiting for
+ * out-of-band push_backup processing by userspace ...
+ */
+ return;
+ }
+ } else if (test_bit(PLOOP_REQ_LOCKOUT, &preq->state) &&
+ test_and_clear_bit(PLOOP_REQ_PUSH_BACKUP, &preq->state)) {
+ /*
+ * preq OUT: out-of-band push_backup processing by
+ * userspace done; preq was re-scheduled
+ */
+ ploop_pb_clear_bit(plo->pbd, preq->req_cluster);
+
+ spin_lock_irq(&plo->lock);
+ del_lockout(preq);
+ if (!list_empty(&preq->delay_list))
+ list_splice_init(&preq->delay_list, plo->ready_queue.prev);
+ spin_unlock_irq(&plo->lock);
+ }
+
if (plo->trans_map) {
err = ploop_find_trans_map(plo->trans_map, preq);
if (err) {
diff --git a/drivers/block/ploop/push_backup.c b/drivers/block/ploop/push_backup.c
index 477caf7..488b8fb 100644
--- a/drivers/block/ploop/push_backup.c
+++ b/drivers/block/ploop/push_backup.c
@@ -146,6 +146,32 @@ static void set_bit_in_map(struct page **map, u64 map_max, u64 blk)
do_bit_in_map(map, map_max, blk, SET_BIT);
}
+static void clear_bit_in_map(struct page **map, u64 map_max, u64 blk)
+{
+ do_bit_in_map(map, map_max, blk, CLEAR_BIT);
+}
+
+static bool check_bit_in_map(struct page **map, u64 map_max, u64 blk)
+{
+ return do_bit_in_map(map, map_max, blk, CHECK_BIT);
+}
+
+/* intentionally lockless */
+void ploop_pb_clear_bit(struct ploop_pushbackup_desc *pbd, cluster_t clu)
+{
+ BUG_ON(!pbd);
+ clear_bit_in_map(pbd->ppb_map, pbd->ppb_block_max, clu);
+}
+
+/* intentionally lockless */
+bool ploop_pb_check_bit(struct ploop_pushbackup_desc *pbd, cluster_t clu)
+{
+ if (!pbd)
+ return false;
+
+ return check_bit_in_map(pbd->ppb_map, pbd->ppb_block_max, clu);
+}
+
static int convert_map_to_map(struct ploop_pushbackup_desc *pbd)
{
struct page **from_map = pbd->cbt_map;
@@ -278,6 +304,12 @@ static void ploop_pb_add_req_to_tree(struct ploop_request *preq,
rb_insert_color(&preq->reloc_link, tree);
}
+static void ploop_pb_add_req_to_pending(struct ploop_pushbackup_desc *pbd,
+ struct ploop_request *preq)
+{
+ ploop_pb_add_req_to_tree(preq, &pbd->pending_tree);
+}
+
static void ploop_pb_add_req_to_reported(struct ploop_pushbackup_desc *pbd,
struct ploop_request *preq)
{
@@ -339,6 +371,33 @@ ploop_pb_get_req_from_reported(struct ploop_pushbackup_desc *pbd,
return ploop_pb_get_req_from_tree(&pbd->reported_tree, clu);
}
+int ploop_pb_preq_add_pending(struct ploop_pushbackup_desc *pbd,
+ struct ploop_request *preq)
+{
+ BUG_ON(!pbd);
+
+ spin_lock(&pbd->ppb_lock);
+
+ if (!test_bit(PLOOP_S_PUSH_BACKUP, &pbd->plo->state)) {
+ spin_unlock(&pbd->ppb_lock);
+ return -EINTR;
+ }
+
+ /* if (preq matches pbd->reported_map) return -EALREADY; */
+ if (preq->req_cluster < pbd->ppb_offset) {
+ spin_unlock(&pbd->ppb_lock);
+ return -EALREADY;
+ }
+
+ ploop_pb_add_req_to_pending(pbd, preq);
+
+ if (pbd->ppb_waiting)
+ complete(&pbd->ppb_comp);
+
+ spin_unlock(&pbd->ppb_lock);
+ return 0;
+}
+
unsigned long ploop_pb_stop(struct ploop_pushbackup_desc *pbd)
{
if (pbd == NULL)
@@ -428,6 +487,9 @@ void ploop_pb_put_reported(struct ploop_pushbackup_desc *pbd,
else
n_found++;
+ if (preq)
+ __set_bit(PLOOP_REQ_PUSH_BACKUP, &preq->state);
+
/*
* If preq not found above, it's unsolicited report. Then it's
* enough to have corresponding bit set in reported_map because if
diff --git a/drivers/block/ploop/push_backup.h b/drivers/block/ploop/push_backup.h
index 482e070..476ac53 100644
--- a/drivers/block/ploop/push_backup.h
+++ b/drivers/block/ploop/push_backup.h
@@ -11,3 +11,9 @@ int ploop_pb_get_pending(struct ploop_pushbackup_desc *pbd,
cluster_t *clu_p, cluster_t *len_p, unsigned n_done);
void ploop_pb_put_reported(struct ploop_pushbackup_desc *pbd,
cluster_t clu, cluster_t len);
+
+void ploop_pb_clear_bit(struct ploop_pushbackup_desc *pbd, cluster_t clu);
+bool ploop_pb_check_bit(struct ploop_pushbackup_desc *pbd, cluster_t clu);
+
+int ploop_pb_preq_add_pending(struct ploop_pushbackup_desc *pbd,
+ struct ploop_request *preq);
diff --git a/include/linux/ploop/ploop.h b/include/linux/ploop/ploop.h
index 09f419d3..762d2fd 100644
--- a/include/linux/ploop/ploop.h
+++ b/include/linux/ploop/ploop.h
@@ -464,6 +464,7 @@ enum
PLOOP_REQ_FORCE_FLUSH, /*force flush by engine */
PLOOP_REQ_KAIO_FSYNC, /*force image fsync by KAIO module */
PLOOP_REQ_POST_SUBMIT, /* preq needs post_submit processing */
+ PLOOP_REQ_PUSH_BACKUP, /* preq was ACKed by userspace push_backup */
};
enum
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