Re: [PATCH 12/13] lightnvm: pblk: close opened chunks

Hans Holmberg
2019-03-04T10:06:08Z

On Mon, Mar 4, 2019 at 9:46 AM Javier González <javier@javigon.com> wrote:
>
> > On 27 Feb 2019, at 18.14, Igor Konopko <igor.j.konopko@intel.com> wrote:
> >
> > When we creating pblk instance with factory
> > flag, there is a possibility that some chunks
> > are in open state, which does not allow to
> > issue erase request to them directly. Such a
> > chunk should be filled with some empty data in
> > order to achieve close state. Without that we
> > are risking that some erase operation will be
> > rejected by the drive due to inproper chunk
> > state.
> >
> > This patch implements closing chunk logic in pblk
> > for that case, when creating instance with factory
> > flag in order to fix that issue
> >
> > Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
> > ---
> > drivers/lightnvm/pblk-core.c | 114 +++++++++++++++++++++++++++++++++++
> > drivers/lightnvm/pblk-init.c | 14 ++++-
> > drivers/lightnvm/pblk.h | 2 +
> > 3 files changed, 128 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> > index fa4dc05608ff..d3c45393f093 100644
> > --- a/drivers/lightnvm/pblk-core.c
> > +++ b/drivers/lightnvm/pblk-core.c
> > @@ -161,6 +161,120 @@ struct nvm_chk_meta *pblk_chunk_get_off(struct pblk *pblk,
> > return meta + ch_off + lun_off + chk_off;
> > }
> >
> > +static void pblk_close_chunk(struct pblk *pblk, struct ppa_addr ppa, int count)
> > +{
> > + struct nvm_tgt_dev *dev = pblk->dev;
> > + struct nvm_geo *geo = &dev->geo;
> > + struct bio *bio;
> > + struct ppa_addr *ppa_list;
> > + struct nvm_rq rqd;
> > + void *meta_list, *data;
> > + dma_addr_t dma_meta_list, dma_ppa_list;
> > + int i, rq_ppas, rq_len, ret;
> > +
> > + meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL, &dma_meta_list);
> > + if (!meta_list)
> > + return;
> > +
> > + ppa_list = meta_list + pblk_dma_meta_size(pblk);
> > + dma_ppa_list = dma_meta_list + pblk_dma_meta_size(pblk);
> > +
> > + rq_ppas = pblk_calc_secs(pblk, count, 0, false);
> > + if (!rq_ppas)
> > + rq_ppas = pblk->min_write_pgs;
> > + rq_len = rq_ppas * geo->csecs;
> > +
> > + data = kzalloc(rq_len, GFP_KERNEL);
> > + if (!data)
> > + goto free_meta_list;
> > +
> > + memset(&rqd, 0, sizeof(struct nvm_rq));
> > + rqd.opcode = NVM_OP_PWRITE;
> > + rqd.nr_ppas = rq_ppas;
> > + rqd.meta_list = meta_list;
> > + rqd.ppa_list = ppa_list;
> > + rqd.dma_ppa_list = dma_ppa_list;
> > + rqd.dma_meta_list = dma_meta_list;
> > +
> > +next_rq:
> > + bio = bio_map_kern(dev->q, data, rq_len, GFP_KERNEL);
> > + if (IS_ERR(bio))
> > + goto out_next;
> > +
> > + bio->bi_iter.bi_sector = 0; /* artificial bio */
> > + bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
> > +
> > + rqd.bio = bio;
> > + for (i = 0; i < rqd.nr_ppas; i++) {
> > + rqd.ppa_list[i] = ppa;
> > + rqd.ppa_list[i].m.sec += i;
> > + pblk_get_meta(pblk, meta_list, i)->lba =
> > + cpu_to_le64(ADDR_EMPTY);
> > + }
> > +
> > + ret = nvm_submit_io_sync(dev, &rqd);
> > + if (ret) {
> > + bio_put(bio);
> > + goto out_next;
> > + }
> > +
> > + if (rqd.error)
> > + goto free_data;
> > +
> > +out_next:
> > + count -= rqd.nr_ppas;
> > + ppa.m.sec += rqd.nr_ppas;
> > + if (count > 0)
> > + goto next_rq;
> > +
> > +free_data:
> > + kfree(data);
> > +free_meta_list:
> > + nvm_dev_dma_free(dev->parent, meta_list, dma_meta_list);
> > +}
> > +
> > +void pblk_close_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *meta)
> > +{
> > + struct nvm_tgt_dev *dev = pblk->dev;
> > + struct nvm_geo *geo = &dev->geo;
> > + struct nvm_chk_meta *chunk_meta;
> > + struct ppa_addr ppa;
> > + int i, j, k, count;
> > +
> > + for (i = 0; i < geo->num_chk; i++) {
> > + for (j = 0; j < geo->num_lun; j++) {
> > + for (k = 0; k < geo->num_ch; k++) {
> > + ppa.ppa = 0;
> > + ppa.m.grp = k;
> > + ppa.m.pu = j;
> > + ppa.m.chk = i;
> > +
> > + chunk_meta = pblk_chunk_get_off(pblk,
> > + meta, ppa);
> > + if (chunk_meta->state == NVM_CHK_ST_OPEN) {
> > + ppa.m.sec = chunk_meta->wp;
> > + count = geo->clba - chunk_meta->wp;
> > + pblk_close_chunk(pblk, ppa, count);
> > + }
> > + }
> > + }
> > + }
> > +}
> > +
> > +bool pblk_are_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *meta)
> > +{
> > + struct nvm_tgt_dev *dev = pblk->dev;
> > + struct nvm_geo *geo = &dev->geo;
> > + int i;
> > +
> > + for (i = 0; i < geo->all_luns; i++) {
> > + if (meta[i].state == NVM_CHK_ST_OPEN)
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
> > void __pblk_map_invalidate(struct pblk *pblk, struct pblk_line *line,
> > u64 paddr)
> > {
> > diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> > index 9913a4514eb6..83abe6960b46 100644
> > --- a/drivers/lightnvm/pblk-init.c
> > +++ b/drivers/lightnvm/pblk-init.c
> > @@ -1028,13 +1028,14 @@ static int pblk_line_meta_init(struct pblk *pblk)
> > return 0;
> > }
> >
> > -static int pblk_lines_init(struct pblk *pblk)
> > +static int pblk_lines_init(struct pblk *pblk, bool factory_init)
> > {
> > struct pblk_line_mgmt *l_mg = &pblk->l_mg;
> > struct pblk_line *line;
> > void *chunk_meta;
> > int nr_free_chks = 0;
> > int i, ret;
> > + bool retry = false;
> >
> > ret = pblk_line_meta_init(pblk);
> > if (ret)
> > @@ -1048,12 +1049,21 @@ static int pblk_lines_init(struct pblk *pblk)
> > if (ret)
> > goto fail_free_meta;
> >
> > +get_chunk_meta:
> > chunk_meta = pblk_get_chunk_meta(pblk);
> > if (IS_ERR(chunk_meta)) {
> > ret = PTR_ERR(chunk_meta);
> > goto fail_free_luns;
> > }
> >
> > + if (factory_init && !retry &&
> > + pblk_are_opened_chunks(pblk, chunk_meta)) {
> > + pblk_close_opened_chunks(pblk, chunk_meta);
> > + retry = true;
> > + vfree(chunk_meta);
> > + goto get_chunk_meta;
> > + }
> > +
> > pblk->lines = kcalloc(l_mg->nr_lines, sizeof(struct pblk_line),
> > GFP_KERNEL);
> > if (!pblk->lines) {
> > @@ -1244,7 +1254,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
> > goto fail;
> > }
> >
> > - ret = pblk_lines_init(pblk);
> > + ret = pblk_lines_init(pblk, flags & NVM_TARGET_FACTORY);
> > if (ret) {
> > pblk_err(pblk, "could not initialize lines\n");
> > goto fail_free_core;
> > diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
> > index b266563508e6..b248642c4dfb 100644
> > --- a/drivers/lightnvm/pblk.h
> > +++ b/drivers/lightnvm/pblk.h
> > @@ -793,6 +793,8 @@ struct nvm_chk_meta *pblk_get_chunk_meta(struct pblk *pblk);
> > struct nvm_chk_meta *pblk_chunk_get_off(struct pblk *pblk,
> > struct nvm_chk_meta *lp,
> > struct ppa_addr ppa);
> > +void pblk_close_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *_meta);
> > +bool pblk_are_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *_meta);
> > void pblk_log_write_err(struct pblk *pblk, struct nvm_rq *rqd);
> > void pblk_log_read_err(struct pblk *pblk, struct nvm_rq *rqd);
> > int pblk_submit_io(struct pblk *pblk, struct nvm_rq *rqd);
> > --
> > 2.17.1
>
> I know that the OCSSD 2.0 spec does not allow to transition from open to
> free, but to me this is a spec bug as there is no underlying issue in
> reading an open block. Note that all controllers I know support this,
> and the upcoming Denali spec. fixes this too.

+ Klaus whom I discussed this with.
Yeah, i think that "early reset" is a nice feature. It would be nice
to extend the OCSSD spec with a new capabilities bit indicating if
this is indeed supported or not.
Matias: what do you think?

>
> Besides, the factory flag is intended to start a pblk instance
> immediately, without having to pay the price of padding any past device
> state. If you still want to do this, I think this belongs in a user space tool.
>

Hear, hear!

Serially padding any open chunks during -f create call would be
terrible user experience.
Lets say that padding a chunk takes one second, we would, in a
worst-case scenario in an example disk, be stuck in a syscall for
1*64*1000 seconds ~ 17 hours.

A tool, like dm-zoned's dmzadm would be the right approach, see
Documentation/device-mapper/dm-zoned.txt
All new pblk instances would then have to be pre-formatted with "pblkadm"

A new physical storage format containing a superblock would also be a good idea.

/ Hans