[Devel] [PATCH rh7 3/3] ploop: io_direct: delay f_op->fsync() until index_update for reloc requests (v3)
Maxim Patlasov
mpatlasov at virtuozzo.com
Wed Jul 27 10:55:21 PDT 2016
Dima,
One week elapsed, still no feedback from you. Do you have something
against this patch?
Thanks,
Maxim
On 07/20/2016 11:21 PM, Maxim Patlasov wrote:
> Commit 9f860e606 introduced an engine to delay fsync: doing
> fallocate(FALLOC_FL_CONVERT_UNWRITTEN) dio_post_submit marks
> io as PLOOP_IO_FSYNC_DELAYED to ensure that fsync happens
> later, when incoming FLUSH|FUA comes.
>
> That was deemed as important because (PSBM-47026):
>
>> This optimization becomes more important due to the fact that customers tend to use pcompact heavily => ploop images grow each day.
> Now, we can easily re-use the engine to delay fsync for reloc
> requests as well. As explained in the description of commit
> 5aa3fe09:
>
>> 1->read_data_from_old_post
>> 2->write_to_new_pos
>> ->sumbit_alloc
>> ->submit_pad
>> ->post_submit->convert_unwritten
>> 3->update_index ->write_page with FLUSH|FUA
>> 4->nullify_old_pos
>> 5->issue_flush
> by the time of step 3 extent coversion is not yet stable because
> belongs to uncommitted transaction. But instead of doing fsync
> inside ->post_submit, we can fsync later, as the very first step
> of write_page for index_update.
>
> Changed in v2:
> - process delayed fsync asynchronously, via PLOOP_E_FSYNC_PENDED eng_state
>
> Changed in v3:
> - use extra arg for ploop_index_wb_proceed_or_delay() instead of ad-hoc PLOOP_REQ_FSYNC_IF_DELAYED
>
> https://jira.sw.ru/browse/PSBM-47026
>
> Signed-off-by: Maxim Patlasov <mpatlasov at virtuozzo.com>
> ---
> drivers/block/ploop/dev.c | 9 +++++++--
> drivers/block/ploop/map.c | 32 ++++++++++++++++++++++++++++----
> include/linux/ploop/ploop.h | 1 +
> 3 files changed, 36 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
> index df3eec9..ed60b1f 100644
> --- a/drivers/block/ploop/dev.c
> +++ b/drivers/block/ploop/dev.c
> @@ -2720,6 +2720,11 @@ restart:
> ploop_index_wb_complete(preq);
> break;
>
> + case PLOOP_E_FSYNC_PENDED:
> + /* fsync done */
> + ploop_index_wb_proceed(preq);
> + break;
> +
> default:
> BUG();
> }
> @@ -4106,7 +4111,7 @@ static void ploop_relocate(struct ploop_device * plo)
> preq->bl.tail = preq->bl.head = NULL;
> preq->req_cluster = 0;
> preq->req_size = 0;
> - preq->req_rw = WRITE_SYNC|REQ_FUA;
> + preq->req_rw = WRITE_SYNC;
> preq->eng_state = PLOOP_E_ENTRY;
> preq->state = (1 << PLOOP_REQ_SYNC) | (1 << PLOOP_REQ_RELOC_A);
> preq->error = 0;
> @@ -4410,7 +4415,7 @@ static void ploop_relocblks_process(struct ploop_device *plo)
> preq->bl.tail = preq->bl.head = NULL;
> preq->req_cluster = ~0U; /* uninitialized */
> preq->req_size = 0;
> - preq->req_rw = WRITE_SYNC|REQ_FUA;
> + preq->req_rw = WRITE_SYNC;
> preq->eng_state = PLOOP_E_ENTRY;
> preq->state = (1 << PLOOP_REQ_SYNC) | (1 << PLOOP_REQ_RELOC_S);
> preq->error = 0;
> diff --git a/drivers/block/ploop/map.c b/drivers/block/ploop/map.c
> index 5f7fd66..715dc15 100644
> --- a/drivers/block/ploop/map.c
> +++ b/drivers/block/ploop/map.c
> @@ -915,6 +915,24 @@ void ploop_index_wb_proceed(struct ploop_request * preq)
> put_page(page);
> }
>
> +static void ploop_index_wb_proceed_or_delay(struct ploop_request * preq,
> + int do_fsync_if_delayed)
> +{
> + if (do_fsync_if_delayed) {
> + struct map_node * m = preq->map;
> + struct ploop_delta * top_delta = map_top_delta(m->parent);
> + struct ploop_io * top_io = &top_delta->io;
> +
> + if (test_bit(PLOOP_IO_FSYNC_DELAYED, &top_io->io_state)) {
> + preq->eng_state = PLOOP_E_FSYNC_PENDED;
> + ploop_add_req_to_fsync_queue(preq);
> + return;
> + }
> + }
> +
> + ploop_index_wb_proceed(preq);
> +}
> +
> /* Data write is commited. Now we need to update index. */
>
> void ploop_index_update(struct ploop_request * preq)
> @@ -927,6 +945,7 @@ void ploop_index_update(struct ploop_request * preq)
> int old_level;
> struct page * page;
> unsigned long state = READ_ONCE(preq->state);
> + int do_fsync_if_delayed = 0;
>
> /* No way back, we are going to initiate index write. */
>
> @@ -985,10 +1004,12 @@ void ploop_index_update(struct ploop_request * preq)
> preq->req_rw &= ~REQ_FLUSH;
>
> /* Relocate requires consistent index update */
> - if (state & (PLOOP_REQ_RELOC_A_FL|PLOOP_REQ_RELOC_S_FL))
> + if (state & (PLOOP_REQ_RELOC_A_FL|PLOOP_REQ_RELOC_S_FL)) {
> preq->req_index_update_rw |= (REQ_FLUSH | REQ_FUA);
> + do_fsync_if_delayed = 1;
> + }
>
> - ploop_index_wb_proceed(preq);
> + ploop_index_wb_proceed_or_delay(preq, do_fsync_if_delayed);
> return;
>
> enomem:
> @@ -1109,6 +1130,7 @@ static void map_wb_complete(struct map_node * m, int err)
> int delayed = 0;
> unsigned int idx;
> unsigned long rw;
> + int do_fsync_if_delayed = 0;
>
> /* First, complete processing of written back indices,
> * finally instantiate indices in mapping cache.
> @@ -1206,8 +1228,10 @@ static void map_wb_complete(struct map_node * m, int err)
>
> state = READ_ONCE(preq->state);
> /* Relocate requires consistent index update */
> - if (state & (PLOOP_REQ_RELOC_A_FL|PLOOP_REQ_RELOC_S_FL))
> + if (state & (PLOOP_REQ_RELOC_A_FL|PLOOP_REQ_RELOC_S_FL)) {
> rw |= (REQ_FLUSH | REQ_FUA);
> + do_fsync_if_delayed = 1;
> + }
>
> preq->eng_state = PLOOP_E_INDEX_WB;
> get_page(page);
> @@ -1234,7 +1258,7 @@ static void map_wb_complete(struct map_node * m, int err)
> plo->st.map_multi_writes++;
>
> main_preq->req_index_update_rw = rw;
> - ploop_index_wb_proceed(main_preq);
> + ploop_index_wb_proceed_or_delay(main_preq, do_fsync_if_delayed);
> }
>
> void
> diff --git a/include/linux/ploop/ploop.h b/include/linux/ploop/ploop.h
> index d8e01b6..33733e9 100644
> --- a/include/linux/ploop/ploop.h
> +++ b/include/linux/ploop/ploop.h
> @@ -513,6 +513,7 @@ enum
> PLOOP_E_ZERO_INDEX, /* Zeroing index of free block; original request
> can use .submit on completion */
> PLOOP_E_DELTA_ZERO_INDEX,/* the same but for PLOOP_E_DELTA_READ */
> + PLOOP_E_FSYNC_PENDED, /* INDEX_WB needs io->ops->sync() to proceed */
> };
>
> #define BIO_BDEV_REUSED 14 /* io_context is stored in bi_bdev */
>
More information about the Devel
mailing list