[PATCH v2 0/3] Rework write error handling in pblk

[PATCH v2 0/3] Rework write error handling in pblk

[Hans Holmberg]

From: Hans Holmberg <hans.holmberg@cnexlabs.com>

This patch series fixes the(currently incomplete) write error handling 
in pblk by:

 * queuing and re-submitting failed writes in the write buffer
 * evacuating valid data data in lines with write failures, so the
   chunk(s) with write failures can be reset to a known state by the fw

Lines with failures in smeta are put back on the free list.
Failed chunks will be reset on the next use.

If a write failes in emeta, the lba list is cached so the line can be 
garbage collected without scanning the out-of-band area.

Changes in V2:
- Added the recov_writes counter increase to the new path
- Moved lba list emeta reading during gc to a separate function
- Allocating the saved lba list with pblk_malloc instead of kmalloc
- Fixed formatting issues
- Removed dead code

Hans Holmberg (3):
  lightnvm: pblk: rework write error recovery path
  lightnvm: pblk: garbage collect lines with failed writes
  lightnvm: pblk: fix smeta write error path

 drivers/lightnvm/pblk-core.c     |  52 +++++++-
 drivers/lightnvm/pblk-gc.c       | 102 +++++++++------
 drivers/lightnvm/pblk-init.c     |  47 ++++---
 drivers/lightnvm/pblk-rb.c       |  39 ------
 drivers/lightnvm/pblk-recovery.c |  91 -------------
 drivers/lightnvm/pblk-rl.c       |  29 ++++-
 drivers/lightnvm/pblk-sysfs.c    |  15 ++-
 drivers/lightnvm/pblk-write.c    | 269 ++++++++++++++++++++++++++-------------
 drivers/lightnvm/pblk.h          |  36 ++++--
 9 files changed, 384 insertions(+), 296 deletions(-)

-- 
2.7.4

[PATCH v2 1/3] lightnvm: pblk: rework write error recovery path

[Hans Holmberg]

From: Hans Holmberg <hans.holmberg@cnexlabs.com>

The write error recovery path is incomplete, so rework
the write error recovery handling to do resubmits directly
from the write buffer.

When a write error occurs, the remaining sectors in the chunk are
mapped out and invalidated and the request inserted in a resubmit list.

The writer thread checks if there are any requests to resubmit,
scans and invalidates any lbas that have been overwritten by later
writes and resubmits the failed entries.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
---
 drivers/lightnvm/pblk-init.c     |   2 +
 drivers/lightnvm/pblk-rb.c       |  39 ------
 drivers/lightnvm/pblk-recovery.c |  91 -------------
 drivers/lightnvm/pblk-write.c    | 267 ++++++++++++++++++++++++++-------------
 drivers/lightnvm/pblk.h          |  11 +-
 5 files changed, 181 insertions(+), 229 deletions(-)

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index bfc488d..6f06727 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -426,6 +426,7 @@ static int pblk_core_init(struct pblk *pblk)
 		goto free_r_end_wq;
 
 	INIT_LIST_HEAD(&pblk->compl_list);
+	INIT_LIST_HEAD(&pblk->resubmit_list);
 
 	return 0;
 
@@ -1185,6 +1186,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
 	pblk->state = PBLK_STATE_RUNNING;
 	pblk->gc.gc_enabled = 0;
 
+	spin_lock_init(&pblk->resubmit_lock);
 	spin_lock_init(&pblk->trans_lock);
 	spin_lock_init(&pblk->lock);
 
diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
index 024a366..00cd1f2 100644
--- a/drivers/lightnvm/pblk-rb.c
+++ b/drivers/lightnvm/pblk-rb.c
@@ -503,45 +503,6 @@ int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries,
 }
 
 /*
- * The caller of this function must ensure that the backpointer will not
- * overwrite the entries passed on the list.
- */
-unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio,
-				      struct list_head *list,
-				      unsigned int max)
-{
-	struct pblk_rb_entry *entry, *tentry;
-	struct page *page;
-	unsigned int read = 0;
-	int ret;
-
-	list_for_each_entry_safe(entry, tentry, list, index) {
-		if (read > max) {
-			pr_err("pblk: too many entries on list\n");
-			goto out;
-		}
-
-		page = virt_to_page(entry->data);
-		if (!page) {
-			pr_err("pblk: could not allocate write bio page\n");
-			goto out;
-		}
-
-		ret = bio_add_page(bio, page, rb->seg_size, 0);
-		if (ret != rb->seg_size) {
-			pr_err("pblk: could not add page to write bio\n");
-			goto out;
-		}
-
-		list_del(&entry->index);
-		read++;
-	}
-
-out:
-	return read;
-}
-
-/*
  * Read available entries on rb and add them to the given bio. To avoid a memory
  * copy, a page reference to the write buffer is used to be added to the bio.
  *
diff --git a/drivers/lightnvm/pblk-recovery.c b/drivers/lightnvm/pblk-recovery.c
index 9cb6d5d..5983428 100644
--- a/drivers/lightnvm/pblk-recovery.c
+++ b/drivers/lightnvm/pblk-recovery.c
@@ -16,97 +16,6 @@
 
 #include "pblk.h"
 
-void pblk_submit_rec(struct work_struct *work)
-{
-	struct pblk_rec_ctx *recovery =
-			container_of(work, struct pblk_rec_ctx, ws_rec);
-	struct pblk *pblk = recovery->pblk;
-	struct nvm_rq *rqd = recovery->rqd;
-	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
-	struct bio *bio;
-	unsigned int nr_rec_secs;
-	unsigned int pgs_read;
-	int ret;
-
-	nr_rec_secs = bitmap_weight((unsigned long int *)&rqd->ppa_status,
-								NVM_MAX_VLBA);
-
-	bio = bio_alloc(GFP_KERNEL, nr_rec_secs);
-
-	bio->bi_iter.bi_sector = 0;
-	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
-	rqd->bio = bio;
-	rqd->nr_ppas = nr_rec_secs;
-
-	pgs_read = pblk_rb_read_to_bio_list(&pblk->rwb, bio, &recovery->failed,
-								nr_rec_secs);
-	if (pgs_read != nr_rec_secs) {
-		pr_err("pblk: could not read recovery entries\n");
-		goto err;
-	}
-
-	if (pblk_setup_w_rec_rq(pblk, rqd, c_ctx)) {
-		pr_err("pblk: could not setup recovery request\n");
-		goto err;
-	}
-
-#ifdef CONFIG_NVM_DEBUG
-	atomic_long_add(nr_rec_secs, &pblk->recov_writes);
-#endif
-
-	ret = pblk_submit_io(pblk, rqd);
-	if (ret) {
-		pr_err("pblk: I/O submission failed: %d\n", ret);
-		goto err;
-	}
-
-	mempool_free(recovery, pblk->rec_pool);
-	return;
-
-err:
-	bio_put(bio);
-	pblk_free_rqd(pblk, rqd, PBLK_WRITE);
-}
-
-int pblk_recov_setup_rq(struct pblk *pblk, struct pblk_c_ctx *c_ctx,
-			struct pblk_rec_ctx *recovery, u64 *comp_bits,
-			unsigned int comp)
-{
-	struct nvm_rq *rec_rqd;
-	struct pblk_c_ctx *rec_ctx;
-	int nr_entries = c_ctx->nr_valid + c_ctx->nr_padded;
-
-	rec_rqd = pblk_alloc_rqd(pblk, PBLK_WRITE);
-	rec_ctx = nvm_rq_to_pdu(rec_rqd);
-
-	/* Copy completion bitmap, but exclude the first X completed entries */
-	bitmap_shift_right((unsigned long int *)&rec_rqd->ppa_status,
-				(unsigned long int *)comp_bits,
-				comp, NVM_MAX_VLBA);
-
-	/* Save the context for the entries that need to be re-written and
-	 * update current context with the completed entries.
-	 */
-	rec_ctx->sentry = pblk_rb_wrap_pos(&pblk->rwb, c_ctx->sentry + comp);
-	if (comp >= c_ctx->nr_valid) {
-		rec_ctx->nr_valid = 0;
-		rec_ctx->nr_padded = nr_entries - comp;
-
-		c_ctx->nr_padded = comp - c_ctx->nr_valid;
-	} else {
-		rec_ctx->nr_valid = c_ctx->nr_valid - comp;
-		rec_ctx->nr_padded = c_ctx->nr_padded;
-
-		c_ctx->nr_valid = comp;
-		c_ctx->nr_padded = 0;
-	}
-
-	recovery->rqd = rec_rqd;
-	recovery->pblk = pblk;
-
-	return 0;
-}
-
 int pblk_recov_check_emeta(struct pblk *pblk, struct line_emeta *emeta_buf)
 {
 	u32 crc;
diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index 3e6f1eb..f62e432f 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -103,68 +103,149 @@ static void pblk_complete_write(struct pblk *pblk, struct nvm_rq *rqd,
 	pblk_rb_sync_end(&pblk->rwb, &flags);
 }
 
-/* When a write fails, we are not sure whether the block has grown bad or a page
- * range is more susceptible to write errors. If a high number of pages fail, we
- * assume that the block is bad and we mark it accordingly. In all cases, we
- * remap and resubmit the failed entries as fast as possible; if a flush is
- * waiting on a completion, the whole stack would stall otherwise.
- */
-static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
+/* Map remaining sectors in chunk, starting from ppa */
+static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
 {
-	void *comp_bits = &rqd->ppa_status;
-	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
-	struct pblk_rec_ctx *recovery;
-	struct ppa_addr *ppa_list = rqd->ppa_list;
-	int nr_ppas = rqd->nr_ppas;
-	unsigned int c_entries;
-	int bit, ret;
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line *line;
+	struct ppa_addr map_ppa = *ppa;
+	u64 paddr;
+	int done = 0;
 
-	if (unlikely(nr_ppas == 1))
-		ppa_list = &rqd->ppa_addr;
+	line = &pblk->lines[pblk_ppa_to_line(*ppa)];
+	spin_lock(&line->lock);
 
-	recovery = mempool_alloc(pblk->rec_pool, GFP_ATOMIC);
+	while (!done)  {
+		paddr = pblk_dev_ppa_to_line_addr(pblk, map_ppa);
 
-	INIT_LIST_HEAD(&recovery->failed);
+		if (!test_and_set_bit(paddr, line->map_bitmap))
+			line->left_msecs--;
 
-	bit = -1;
-	while ((bit = find_next_bit(comp_bits, nr_ppas, bit + 1)) < nr_ppas) {
-		struct pblk_rb_entry *entry;
-		struct ppa_addr ppa;
+		if (!test_and_set_bit(paddr, line->invalid_bitmap))
+			le32_add_cpu(line->vsc, -1);
 
-		/* Logic error */
-		if (bit > c_ctx->nr_valid) {
-			WARN_ONCE(1, "pblk: corrupted write request\n");
-			mempool_free(recovery, pblk->rec_pool);
-			goto out;
+		if (geo->version == NVM_OCSSD_SPEC_12) {
+			map_ppa.ppa++;
+			if (map_ppa.g.pg == geo->num_pg)
+				done = 1;
+		} else {
+			map_ppa.m.sec++;
+			if (map_ppa.m.sec == geo->clba)
+				done = 1;
 		}
+	}
 
-		ppa = ppa_list[bit];
-		entry = pblk_rb_sync_scan_entry(&pblk->rwb, &ppa);
-		if (!entry) {
-			pr_err("pblk: could not scan entry on write failure\n");
-			mempool_free(recovery, pblk->rec_pool);
-			goto out;
-		}
+	spin_unlock(&line->lock);
+}
+
+static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
+				  unsigned int nr_entries)
+{
+	struct pblk_rb *rb = &pblk->rwb;
+	struct pblk_rb_entry *entry;
+	struct pblk_line *line;
+	struct pblk_w_ctx *w_ctx;
+	struct ppa_addr ppa_l2p;
+	int flags;
+	unsigned int pos, i;
+
+	spin_lock(&pblk->trans_lock);
+	pos = sentry;
+	for (i = 0; i < nr_entries; i++) {
+		entry = &rb->entries[pos];
+		w_ctx = &entry->w_ctx;
+
+		/* Check if the lba has been overwritten */
+		ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
+		if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
+			w_ctx->lba = ADDR_EMPTY;
+
+		/* Mark up the entry as submittable again */
+		flags = READ_ONCE(w_ctx->flags);
+		flags |= PBLK_WRITTEN_DATA;
+		/* Release flags on write context. Protect from writes */
+		smp_store_release(&w_ctx->flags, flags);
 
-		/* The list is filled first and emptied afterwards. No need for
-		 * protecting it with a lock
+		/* Decrese the reference count to the line as we will
+		 * re-map these entries
 		 */
-		list_add_tail(&entry->index, &recovery->failed);
+		line = &pblk->lines[pblk_ppa_to_line(w_ctx->ppa)];
+		kref_put(&line->ref, pblk_line_put);
+
+		pos = (pos + 1) & (rb->nr_entries - 1);
 	}
+	spin_unlock(&pblk->trans_lock);
+}
 
-	c_entries = find_first_bit(comp_bits, nr_ppas);
-	ret = pblk_recov_setup_rq(pblk, c_ctx, recovery, comp_bits, c_entries);
-	if (ret) {
-		pr_err("pblk: could not recover from write failure\n");
-		mempool_free(recovery, pblk->rec_pool);
-		goto out;
+static void pblk_queue_resubmit(struct pblk *pblk, struct pblk_c_ctx *c_ctx)
+{
+	struct pblk_c_ctx *r_ctx;
+
+	r_ctx = kzalloc(sizeof(struct pblk_c_ctx), GFP_KERNEL);
+	if (!r_ctx)
+		return;
+
+	r_ctx->lun_bitmap = NULL;
+	r_ctx->sentry = c_ctx->sentry;
+	r_ctx->nr_valid = c_ctx->nr_valid;
+	r_ctx->nr_padded = c_ctx->nr_padded;
+
+	spin_lock(&pblk->resubmit_lock);
+	list_add_tail(&r_ctx->list, &pblk->resubmit_list);
+	spin_unlock(&pblk->resubmit_lock);
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(c_ctx->nr_valid, &pblk->recov_writes);
+#endif
+}
+
+static void pblk_submit_rec(struct work_struct *work)
+{
+	struct pblk_rec_ctx *recovery =
+			container_of(work, struct pblk_rec_ctx, ws_rec);
+	struct pblk *pblk = recovery->pblk;
+	struct nvm_rq *rqd = recovery->rqd;
+	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
+	struct ppa_addr *ppa_list;
+
+	pblk_log_write_err(pblk, rqd);
+
+	if (rqd->nr_ppas == 1)
+		ppa_list = &rqd->ppa_addr;
+	else
+		ppa_list = rqd->ppa_list;
+
+	pblk_map_remaining(pblk, ppa_list);
+	pblk_queue_resubmit(pblk, c_ctx);
+
+	pblk_up_rq(pblk, rqd->ppa_list, rqd->nr_ppas, c_ctx->lun_bitmap);
+	if (c_ctx->nr_padded)
+		pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
+							c_ctx->nr_padded);
+	bio_put(rqd->bio);
+	pblk_free_rqd(pblk, rqd, PBLK_WRITE);
+	mempool_free(recovery, pblk->rec_pool);
+
+	atomic_dec(&pblk->inflight_io);
+}
+
+
+static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	struct pblk_rec_ctx *recovery;
+
+	recovery = mempool_alloc(pblk->rec_pool, GFP_ATOMIC);
+	if (!recovery) {
+		pr_err("pblk: could not allocate recovery work\n");
+		return;
 	}
 
+	recovery->pblk = pblk;
+	recovery->rqd = rqd;
+
 	INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
 	queue_work(pblk->close_wq, &recovery->ws_rec);
-
-out:
-	pblk_complete_write(pblk, rqd, c_ctx);
 }
 
 static void pblk_end_io_write(struct nvm_rq *rqd)
@@ -173,8 +254,8 @@ static void pblk_end_io_write(struct nvm_rq *rqd)
 	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
 
 	if (rqd->error) {
-		pblk_log_write_err(pblk, rqd);
-		return pblk_end_w_fail(pblk, rqd);
+		pblk_end_w_fail(pblk, rqd);
+		return;
 	}
 #ifdef CONFIG_NVM_DEBUG
 	else
@@ -266,31 +347,6 @@ static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
 	return 0;
 }
 
-int pblk_setup_w_rec_rq(struct pblk *pblk, struct nvm_rq *rqd,
-			struct pblk_c_ctx *c_ctx)
-{
-	struct pblk_line_meta *lm = &pblk->lm;
-	unsigned long *lun_bitmap;
-	int ret;
-
-	lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
-	if (!lun_bitmap)
-		return -ENOMEM;
-
-	c_ctx->lun_bitmap = lun_bitmap;
-
-	ret = pblk_alloc_w_rq(pblk, rqd, rqd->nr_ppas, pblk_end_io_write);
-	if (ret)
-		return ret;
-
-	pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, c_ctx->nr_valid, 0);
-
-	rqd->ppa_status = (u64)0;
-	rqd->flags = pblk_set_progr_mode(pblk, PBLK_WRITE);
-
-	return ret;
-}
-
 static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
 				  unsigned int secs_to_flush)
 {
@@ -339,6 +395,7 @@ int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 	bio = pblk_bio_map_addr(pblk, data, rq_ppas, rq_len,
 					l_mg->emeta_alloc_type, GFP_KERNEL);
 	if (IS_ERR(bio)) {
+		pr_err("pblk: failed to map emeta io");
 		ret = PTR_ERR(bio);
 		goto fail_free_rqd;
 	}
@@ -515,26 +572,54 @@ static int pblk_submit_write(struct pblk *pblk)
 	unsigned int secs_avail, secs_to_sync, secs_to_com;
 	unsigned int secs_to_flush;
 	unsigned long pos;
+	unsigned int resubmit;
 
-	/* If there are no sectors in the cache, flushes (bios without data)
-	 * will be cleared on the cache threads
-	 */
-	secs_avail = pblk_rb_read_count(&pblk->rwb);
-	if (!secs_avail)
-		return 1;
-
-	secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
-	if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
-		return 1;
-
-	secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail, secs_to_flush);
-	if (secs_to_sync > pblk->max_write_pgs) {
-		pr_err("pblk: bad buffer sync calculation\n");
-		return 1;
-	}
+	spin_lock(&pblk->resubmit_lock);
+	resubmit = !list_empty(&pblk->resubmit_list);
+	spin_unlock(&pblk->resubmit_lock);
+
+	/* Resubmit failed writes first */
+	if (resubmit) {
+		struct pblk_c_ctx *r_ctx;
+
+		spin_lock(&pblk->resubmit_lock);
+		r_ctx = list_first_entry(&pblk->resubmit_list,
+					struct pblk_c_ctx, list);
+		list_del(&r_ctx->list);
+		spin_unlock(&pblk->resubmit_lock);
+
+		secs_avail = r_ctx->nr_valid;
+		pos = r_ctx->sentry;
+
+		pblk_prepare_resubmit(pblk, pos, secs_avail);
+		secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
+				secs_avail);
 
-	secs_to_com = (secs_to_sync > secs_avail) ? secs_avail : secs_to_sync;
-	pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
+		kfree(r_ctx);
+	} else {
+		/* If there are no sectors in the cache,
+		 * flushes (bios without data) will be cleared on
+		 * the cache threads
+		 */
+		secs_avail = pblk_rb_read_count(&pblk->rwb);
+		if (!secs_avail)
+			return 1;
+
+		secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
+		if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
+			return 1;
+
+		secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
+					secs_to_flush);
+		if (secs_to_sync > pblk->max_write_pgs) {
+			pr_err("pblk: bad buffer sync calculation\n");
+			return 1;
+		}
+
+		secs_to_com = (secs_to_sync > secs_avail) ?
+			secs_avail : secs_to_sync;
+		pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
+	}
 
 	bio = bio_alloc(GFP_KERNEL, secs_to_sync);
 
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index 9838d03..f8434a3 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -128,7 +128,6 @@ struct pblk_pad_rq {
 struct pblk_rec_ctx {
 	struct pblk *pblk;
 	struct nvm_rq *rqd;
-	struct list_head failed;
 	struct work_struct ws_rec;
 };
 
@@ -664,6 +663,9 @@ struct pblk {
 
 	struct list_head compl_list;
 
+	spinlock_t resubmit_lock;	 /* Resubmit list lock */
+	struct list_head resubmit_list; /* Resubmit list for failed writes*/
+
 	mempool_t *page_bio_pool;
 	mempool_t *gen_ws_pool;
 	mempool_t *rec_pool;
@@ -713,9 +715,6 @@ void pblk_rb_sync_l2p(struct pblk_rb *rb);
 unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd,
 				 unsigned int pos, unsigned int nr_entries,
 				 unsigned int count);
-unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio,
-				      struct list_head *list,
-				      unsigned int max);
 int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba,
 			struct ppa_addr ppa, int bio_iter, bool advanced_bio);
 unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int entries);
@@ -849,13 +848,9 @@ int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq);
 /*
  * pblk recovery
  */
-void pblk_submit_rec(struct work_struct *work);
 struct pblk_line *pblk_recov_l2p(struct pblk *pblk);
 int pblk_recov_pad(struct pblk *pblk);
 int pblk_recov_check_emeta(struct pblk *pblk, struct line_emeta *emeta);
-int pblk_recov_setup_rq(struct pblk *pblk, struct pblk_c_ctx *c_ctx,
-			struct pblk_rec_ctx *recovery, u64 *comp_bits,
-			unsigned int comp);
 
 /*
  * pblk gc
-- 
2.7.4

[PATCH v2 2/3] lightnvm: pblk: garbage collect lines with failed writes

[Hans Holmberg]

From: Hans Holmberg <hans.holmberg@cnexlabs.com>

Write failures should not happen under normal circumstances,
so in order to bring the chunk back into a known state as soon
as possible, evacuate all the valid data out of the line and let the
fw judge if the block can be written to in the next reset cycle.

Do this by introducing a new gc list for lines with failed writes,
and ensure that the rate limiter allocates a small portion of
the write bandwidth to get the job done.

The lba list is saved in memory for use during gc as we
cannot gurantee that the emeta data is readable if a write
error occurred.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
---
 drivers/lightnvm/pblk-core.c  |  45 ++++++++++++++++++-
 drivers/lightnvm/pblk-gc.c    | 102 +++++++++++++++++++++++++++---------------
 drivers/lightnvm/pblk-init.c  |  45 ++++++++++++-------
 drivers/lightnvm/pblk-rl.c    |  29 ++++++++++--
 drivers/lightnvm/pblk-sysfs.c |  15 ++++++-
 drivers/lightnvm/pblk-write.c |   2 +
 drivers/lightnvm/pblk.h       |  25 +++++++++--
 7 files changed, 199 insertions(+), 64 deletions(-)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 7762e89..413cf3b 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -373,7 +373,13 @@ struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line)
 
 	lockdep_assert_held(&line->lock);
 
-	if (!vsc) {
+	if (line->w_err_gc->has_write_err) {
+		if (line->gc_group != PBLK_LINEGC_WERR) {
+			line->gc_group = PBLK_LINEGC_WERR;
+			move_list = &l_mg->gc_werr_list;
+			pblk_rl_werr_line_in(&pblk->rl);
+		}
+	} else if (!vsc) {
 		if (line->gc_group != PBLK_LINEGC_FULL) {
 			line->gc_group = PBLK_LINEGC_FULL;
 			move_list = &l_mg->gc_full_list;
@@ -1603,8 +1609,13 @@ static void __pblk_line_put(struct pblk *pblk, struct pblk_line *line)
 	line->state = PBLK_LINESTATE_FREE;
 	line->gc_group = PBLK_LINEGC_NONE;
 	pblk_line_free(line);
-	spin_unlock(&line->lock);
 
+	if (line->w_err_gc->has_write_err) {
+		pblk_rl_werr_line_out(&pblk->rl);
+		line->w_err_gc->has_write_err = 0;
+	}
+
+	spin_unlock(&line->lock);
 	atomic_dec(&gc->pipeline_gc);
 
 	spin_lock(&l_mg->free_lock);
@@ -1767,11 +1778,34 @@ void pblk_line_close_meta(struct pblk *pblk, struct pblk_line *line)
 
 	spin_lock(&l_mg->close_lock);
 	spin_lock(&line->lock);
+
+	/* Update the in-memory start address for emeta, in case it has
+	 * shifted due to write errors
+	 */
+	if (line->emeta_ssec != line->cur_sec)
+		line->emeta_ssec = line->cur_sec;
+
 	list_add_tail(&line->list, &l_mg->emeta_list);
 	spin_unlock(&line->lock);
 	spin_unlock(&l_mg->close_lock);
 
 	pblk_line_should_sync_meta(pblk);
+
+
+}
+
+static void pblk_save_lba_list(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	unsigned int lba_list_size = lm->emeta_len[2];
+	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
+	struct pblk_emeta *emeta = line->emeta;
+
+	w_err_gc->lba_list = pblk_malloc(lba_list_size,
+					 l_mg->emeta_alloc_type, GFP_KERNEL);
+	memcpy(w_err_gc->lba_list, emeta_to_lbas(pblk, emeta->buf),
+				lba_list_size);
 }
 
 void pblk_line_close_ws(struct work_struct *work)
@@ -1780,6 +1814,13 @@ void pblk_line_close_ws(struct work_struct *work)
 									ws);
 	struct pblk *pblk = line_ws->pblk;
 	struct pblk_line *line = line_ws->line;
+	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
+
+	/* Write errors makes the emeta start address stored in smeta invalid,
+	 * so keep a copy of the lba list until we've gc'd the line
+	 */
+	if (w_err_gc->has_write_err)
+		pblk_save_lba_list(pblk, line);
 
 	pblk_line_close(pblk, line);
 	mempool_free(line_ws, pblk->gen_ws_pool);
diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
index b0cc277..df88f1b 100644
--- a/drivers/lightnvm/pblk-gc.c
+++ b/drivers/lightnvm/pblk-gc.c
@@ -129,6 +129,53 @@ static void pblk_gc_line_ws(struct work_struct *work)
 	kfree(gc_rq_ws);
 }
 
+static __le64 *get_lba_list_from_emeta(struct pblk *pblk,
+				       struct pblk_line *line)
+{
+	struct line_emeta *emeta_buf;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line_meta *lm = &pblk->lm;
+	unsigned int lba_list_size = lm->emeta_len[2];
+	__le64 *lba_list;
+	int ret;
+
+	emeta_buf = pblk_malloc(lm->emeta_len[0],
+				l_mg->emeta_alloc_type, GFP_KERNEL);
+	if (!emeta_buf)
+		return NULL;
+
+	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
+	if (ret) {
+		pr_err("pblk: line %d read emeta failed (%d)\n",
+				line->id, ret);
+		pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
+		return NULL;
+	}
+
+	/* If this read fails, it means that emeta is corrupted.
+	 * For now, leave the line untouched.
+	 * TODO: Implement a recovery routine that scans and moves
+	 * all sectors on the line.
+	 */
+
+	ret = pblk_recov_check_emeta(pblk, emeta_buf);
+	if (ret) {
+		pr_err("pblk: inconsistent emeta (line %d)\n",
+				line->id);
+		pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
+		return NULL;
+	}
+
+	lba_list = pblk_malloc(lba_list_size,
+			       l_mg->emeta_alloc_type, GFP_KERNEL);
+	if (lba_list)
+		memcpy(lba_list, emeta_to_lbas(pblk, emeta_buf), lba_list_size);
+
+	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
+
+	return lba_list;
+}
+
 static void pblk_gc_line_prepare_ws(struct work_struct *work)
 {
 	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
@@ -138,46 +185,26 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
 	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 	struct pblk_line_meta *lm = &pblk->lm;
 	struct pblk_gc *gc = &pblk->gc;
-	struct line_emeta *emeta_buf;
 	struct pblk_line_ws *gc_rq_ws;
 	struct pblk_gc_rq *gc_rq;
 	__le64 *lba_list;
 	unsigned long *invalid_bitmap;
 	int sec_left, nr_secs, bit;
-	int ret;
 
 	invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_KERNEL);
 	if (!invalid_bitmap)
 		goto fail_free_ws;
 
-	emeta_buf = pblk_malloc(lm->emeta_len[0], l_mg->emeta_alloc_type,
-								GFP_KERNEL);
-	if (!emeta_buf) {
-		pr_err("pblk: cannot use GC emeta\n");
-		goto fail_free_bitmap;
-	}
-
-	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
-	if (ret) {
-		pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
-		goto fail_free_emeta;
-	}
-
-	/* If this read fails, it means that emeta is corrupted. For now, leave
-	 * the line untouched. TODO: Implement a recovery routine that scans and
-	 * moves all sectors on the line.
-	 */
-
-	ret = pblk_recov_check_emeta(pblk, emeta_buf);
-	if (ret) {
-		pr_err("pblk: inconsistent emeta (line %d)\n", line->id);
-		goto fail_free_emeta;
-	}
-
-	lba_list = emeta_to_lbas(pblk, emeta_buf);
-	if (!lba_list) {
-		pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
-		goto fail_free_emeta;
+	if (line->w_err_gc->has_write_err) {
+		lba_list = line->w_err_gc->lba_list;
+		line->w_err_gc->lba_list = NULL;
+	} else {
+		lba_list = get_lba_list_from_emeta(pblk, line);
+		if (!lba_list) {
+			pr_err("pblk: could not interpret emeta (line %d)\n",
+					line->id);
+			goto fail_free_ws;
+		}
 	}
 
 	spin_lock(&line->lock);
@@ -187,14 +214,14 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
 
 	if (sec_left < 0) {
 		pr_err("pblk: corrupted GC line (%d)\n", line->id);
-		goto fail_free_emeta;
+		goto fail_free_lba_list;
 	}
 
 	bit = -1;
 next_rq:
 	gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
 	if (!gc_rq)
-		goto fail_free_emeta;
+		goto fail_free_lba_list;
 
 	nr_secs = 0;
 	do {
@@ -240,7 +267,7 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
 		goto next_rq;
 
 out:
-	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
+	pblk_mfree(lba_list, l_mg->emeta_alloc_type);
 	kfree(line_ws);
 	kfree(invalid_bitmap);
 
@@ -251,9 +278,8 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
 
 fail_free_gc_rq:
 	kfree(gc_rq);
-fail_free_emeta:
-	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
-fail_free_bitmap:
+fail_free_lba_list:
+	pblk_mfree(lba_list, l_mg->emeta_alloc_type);
 	kfree(invalid_bitmap);
 fail_free_ws:
 	kfree(line_ws);
@@ -349,12 +375,14 @@ static struct pblk_line *pblk_gc_get_victim_line(struct pblk *pblk,
 static bool pblk_gc_should_run(struct pblk_gc *gc, struct pblk_rl *rl)
 {
 	unsigned int nr_blocks_free, nr_blocks_need;
+	unsigned int werr_lines = atomic_read(&rl->werr_lines);
 
 	nr_blocks_need = pblk_rl_high_thrs(rl);
 	nr_blocks_free = pblk_rl_nr_free_blks(rl);
 
 	/* This is not critical, no need to take lock here */
-	return ((gc->gc_active) && (nr_blocks_need > nr_blocks_free));
+	return ((werr_lines > 0) ||
+		((gc->gc_active) && (nr_blocks_need > nr_blocks_free)));
 }
 
 void pblk_gc_free_full_lines(struct pblk *pblk)
diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index 6f06727..931ba32 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -493,11 +493,16 @@ static void pblk_line_mg_free(struct pblk *pblk)
 	}
 }
 
-static void pblk_line_meta_free(struct pblk_line *line)
+static void pblk_line_meta_free(struct pblk_line_mgmt *l_mg, struct pblk_line *line)
 {
+	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
+
 	kfree(line->blk_bitmap);
 	kfree(line->erase_bitmap);
 	kfree(line->chks);
+
+	pblk_mfree(w_err_gc->lba_list, l_mg->emeta_alloc_type);
+	kfree(w_err_gc);
 }
 
 static void pblk_lines_free(struct pblk *pblk)
@@ -511,7 +516,7 @@ static void pblk_lines_free(struct pblk *pblk)
 		line = &pblk->lines[i];
 
 		pblk_line_free(line);
-		pblk_line_meta_free(line);
+		pblk_line_meta_free(l_mg, line);
 	}
 	spin_unlock(&l_mg->free_lock);
 
@@ -813,20 +818,28 @@ static int pblk_alloc_line_meta(struct pblk *pblk, struct pblk_line *line)
 		return -ENOMEM;
 
 	line->erase_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
-	if (!line->erase_bitmap) {
-		kfree(line->blk_bitmap);
-		return -ENOMEM;
-	}
+	if (!line->erase_bitmap)
+		goto free_blk_bitmap;
+
 
 	line->chks = kmalloc(lm->blk_per_line * sizeof(struct nvm_chk_meta),
 								GFP_KERNEL);
-	if (!line->chks) {
-		kfree(line->erase_bitmap);
-		kfree(line->blk_bitmap);
-		return -ENOMEM;
-	}
+	if (!line->chks)
+		goto free_erase_bitmap;
+
+	line->w_err_gc = kzalloc(sizeof(struct pblk_w_err_gc), GFP_KERNEL);
+	if (!line->w_err_gc)
+		goto free_chks;
 
 	return 0;
+
+free_chks:
+	kfree(line->chks);
+free_erase_bitmap:
+	kfree(line->erase_bitmap);
+free_blk_bitmap:
+	kfree(line->blk_bitmap);
+	return -ENOMEM;
 }
 
 static int pblk_line_mg_init(struct pblk *pblk)
@@ -851,12 +864,14 @@ static int pblk_line_mg_init(struct pblk *pblk)
 	INIT_LIST_HEAD(&l_mg->gc_mid_list);
 	INIT_LIST_HEAD(&l_mg->gc_low_list);
 	INIT_LIST_HEAD(&l_mg->gc_empty_list);
+	INIT_LIST_HEAD(&l_mg->gc_werr_list);
 
 	INIT_LIST_HEAD(&l_mg->emeta_list);
 
-	l_mg->gc_lists[0] = &l_mg->gc_high_list;
-	l_mg->gc_lists[1] = &l_mg->gc_mid_list;
-	l_mg->gc_lists[2] = &l_mg->gc_low_list;
+	l_mg->gc_lists[0] = &l_mg->gc_werr_list;
+	l_mg->gc_lists[1] = &l_mg->gc_high_list;
+	l_mg->gc_lists[2] = &l_mg->gc_mid_list;
+	l_mg->gc_lists[3] = &l_mg->gc_low_list;
 
 	spin_lock_init(&l_mg->free_lock);
 	spin_lock_init(&l_mg->close_lock);
@@ -1063,7 +1078,7 @@ static int pblk_lines_init(struct pblk *pblk)
 
 fail_free_lines:
 	while (--i >= 0)
-		pblk_line_meta_free(&pblk->lines[i]);
+		pblk_line_meta_free(l_mg, &pblk->lines[i]);
 	kfree(pblk->lines);
 fail_free_chunk_meta:
 	kfree(chunk_meta);
diff --git a/drivers/lightnvm/pblk-rl.c b/drivers/lightnvm/pblk-rl.c
index 883a711..6a0616a 100644
--- a/drivers/lightnvm/pblk-rl.c
+++ b/drivers/lightnvm/pblk-rl.c
@@ -73,6 +73,16 @@ void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries)
 	pblk_rl_kick_u_timer(rl);
 }
 
+void pblk_rl_werr_line_in(struct pblk_rl *rl)
+{
+	atomic_inc(&rl->werr_lines);
+}
+
+void pblk_rl_werr_line_out(struct pblk_rl *rl)
+{
+	atomic_dec(&rl->werr_lines);
+}
+
 void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries)
 {
 	atomic_add(nr_entries, &rl->rb_gc_cnt);
@@ -99,11 +109,21 @@ static void __pblk_rl_update_rates(struct pblk_rl *rl,
 {
 	struct pblk *pblk = container_of(rl, struct pblk, rl);
 	int max = rl->rb_budget;
+	int werr_gc_needed = atomic_read(&rl->werr_lines);
 
 	if (free_blocks >= rl->high) {
-		rl->rb_user_max = max;
-		rl->rb_gc_max = 0;
-		rl->rb_state = PBLK_RL_HIGH;
+		if (werr_gc_needed) {
+			/* Allocate a small budget for recovering
+			 * lines with write errors
+			 */
+			rl->rb_gc_max = 1 << rl->rb_windows_pw;
+			rl->rb_user_max = max - rl->rb_gc_max;
+			rl->rb_state = PBLK_RL_WERR;
+		} else {
+			rl->rb_user_max = max;
+			rl->rb_gc_max = 0;
+			rl->rb_state = PBLK_RL_OFF;
+		}
 	} else if (free_blocks < rl->high) {
 		int shift = rl->high_pw - rl->rb_windows_pw;
 		int user_windows = free_blocks >> shift;
@@ -124,7 +144,7 @@ static void __pblk_rl_update_rates(struct pblk_rl *rl,
 		rl->rb_state = PBLK_RL_LOW;
 	}
 
-	if (rl->rb_state == (PBLK_RL_MID | PBLK_RL_LOW))
+	if (rl->rb_state != PBLK_RL_OFF)
 		pblk_gc_should_start(pblk);
 	else
 		pblk_gc_should_stop(pblk);
@@ -221,6 +241,7 @@ void pblk_rl_init(struct pblk_rl *rl, int budget)
 	atomic_set(&rl->rb_user_cnt, 0);
 	atomic_set(&rl->rb_gc_cnt, 0);
 	atomic_set(&rl->rb_space, -1);
+	atomic_set(&rl->werr_lines, 0);
 
 	timer_setup(&rl->u_timer, pblk_rl_u_timer, 0);
 
diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c
index e61909a..88a0a7c 100644
--- a/drivers/lightnvm/pblk-sysfs.c
+++ b/drivers/lightnvm/pblk-sysfs.c
@@ -173,6 +173,8 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
 	int free_line_cnt = 0, closed_line_cnt = 0, emeta_line_cnt = 0;
 	int d_line_cnt = 0, l_line_cnt = 0;
 	int gc_full = 0, gc_high = 0, gc_mid = 0, gc_low = 0, gc_empty = 0;
+	int gc_werr = 0;
+
 	int bad = 0, cor = 0;
 	int msecs = 0, cur_sec = 0, vsc = 0, sec_in_line = 0;
 	int map_weight = 0, meta_weight = 0;
@@ -237,6 +239,15 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
 		gc_empty++;
 	}
 
+	list_for_each_entry(line, &l_mg->gc_werr_list, list) {
+		if (line->type == PBLK_LINETYPE_DATA)
+			d_line_cnt++;
+		else if (line->type == PBLK_LINETYPE_LOG)
+			l_line_cnt++;
+		closed_line_cnt++;
+		gc_werr++;
+	}
+
 	list_for_each_entry(line, &l_mg->bad_list, list)
 		bad++;
 	list_for_each_entry(line, &l_mg->corrupt_list, list)
@@ -275,8 +286,8 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
 					l_mg->nr_lines);
 
 	sz += snprintf(page + sz, PAGE_SIZE - sz,
-		"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, queue:%d\n",
-			gc_full, gc_high, gc_mid, gc_low, gc_empty,
+		"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, werr: %d, queue:%d\n",
+			gc_full, gc_high, gc_mid, gc_low, gc_empty, gc_werr,
 			atomic_read(&pblk->gc.read_inflight_gc));
 
 	sz += snprintf(page + sz, PAGE_SIZE - sz,
diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index f62e432f..f33c2c3 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -136,6 +136,7 @@ static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
 		}
 	}
 
+	line->w_err_gc->has_write_err = 1;
 	spin_unlock(&line->lock);
 }
 
@@ -279,6 +280,7 @@ static void pblk_end_io_write_meta(struct nvm_rq *rqd)
 	if (rqd->error) {
 		pblk_log_write_err(pblk, rqd);
 		pr_err("pblk: metadata I/O failed. Line %d\n", line->id);
+		line->w_err_gc->has_write_err = 1;
 	}
 
 	sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index f8434a3..25ad026 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -89,12 +89,14 @@ struct pblk_sec_meta {
 /* The number of GC lists and the rate-limiter states go together. This way the
  * rate-limiter can dictate how much GC is needed based on resource utilization.
  */
-#define PBLK_GC_NR_LISTS 3
+#define PBLK_GC_NR_LISTS 4
 
 enum {
-	PBLK_RL_HIGH = 1,
-	PBLK_RL_MID = 2,
-	PBLK_RL_LOW = 3,
+	PBLK_RL_OFF = 0,
+	PBLK_RL_WERR = 1,
+	PBLK_RL_HIGH = 2,
+	PBLK_RL_MID = 3,
+	PBLK_RL_LOW = 4
 };
 
 #define pblk_dma_meta_size (sizeof(struct pblk_sec_meta) * PBLK_MAX_REQ_ADDRS)
@@ -278,6 +280,8 @@ struct pblk_rl {
 	int rb_user_active;
 	int rb_gc_active;
 
+	atomic_t werr_lines;	/* Number of write error lines that needs gc */
+
 	struct timer_list u_timer;
 
 	unsigned long long nr_secs;
@@ -311,6 +315,7 @@ enum {
 	PBLK_LINEGC_MID = 23,
 	PBLK_LINEGC_HIGH = 24,
 	PBLK_LINEGC_FULL = 25,
+	PBLK_LINEGC_WERR = 26
 };
 
 #define PBLK_MAGIC 0x70626c6b /*pblk*/
@@ -412,6 +417,11 @@ struct pblk_smeta {
 	struct line_smeta *buf;		/* smeta buffer in persistent format */
 };
 
+struct pblk_w_err_gc {
+	int has_write_err;
+	__le64 *lba_list;
+};
+
 struct pblk_line {
 	struct pblk *pblk;
 	unsigned int id;		/* Line number corresponds to the
@@ -457,6 +467,8 @@ struct pblk_line {
 
 	struct kref ref;		/* Write buffer L2P references */
 
+	struct pblk_w_err_gc *w_err_gc;	/* Write error gc recovery metadata */
+
 	spinlock_t lock;		/* Necessary for invalid_bitmap only */
 };
 
@@ -488,6 +500,8 @@ struct pblk_line_mgmt {
 	struct list_head gc_mid_list;	/* Full lines ready to GC, mid isc */
 	struct list_head gc_low_list;	/* Full lines ready to GC, low isc */
 
+	struct list_head gc_werr_list;  /* Write err recovery list */
+
 	struct list_head gc_full_list;	/* Full lines ready to GC, no valid */
 	struct list_head gc_empty_list;	/* Full lines close, all valid */
 
@@ -891,6 +905,9 @@ void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line,
 			    bool used);
 int pblk_rl_is_limit(struct pblk_rl *rl);
 
+void pblk_rl_werr_line_in(struct pblk_rl *rl);
+void pblk_rl_werr_line_out(struct pblk_rl *rl);
+
 /*
  * pblk sysfs
  */
-- 
2.7.4

[PATCH v2 3/3] lightnvm: pblk: fix smeta write error path

[Hans Holmberg]

From: Hans Holmberg <hans.holmberg@cnexlabs.com>

Smeta write errors were previously ignored. Skip these
lines instead and throw them back on the free
list, so the chunks will go through a reset cycle
before we attempt to use the line again.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
---
 drivers/lightnvm/pblk-core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 413cf3b..dec1bb4 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -849,9 +849,10 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
 	atomic_dec(&pblk->inflight_io);
 
 	if (rqd.error) {
-		if (dir == PBLK_WRITE)
+		if (dir == PBLK_WRITE) {
 			pblk_log_write_err(pblk, &rqd);
-		else if (dir == PBLK_READ)
+			ret = 1;
+		} else if (dir == PBLK_READ)
 			pblk_log_read_err(pblk, &rqd);
 	}
 
@@ -1120,7 +1121,7 @@ static int pblk_line_init_bb(struct pblk *pblk, struct pblk_line *line,
 
 	if (init && pblk_line_submit_smeta_io(pblk, line, off, PBLK_WRITE)) {
 		pr_debug("pblk: line smeta I/O failed. Retry\n");
-		return 1;
+		return 0;
 	}
 
 	bitmap_copy(line->invalid_bitmap, line->map_bitmap, lm->sec_per_line);
-- 
2.7.4

Re: [PATCH v2 0/3] Rework write error handling in pblk

[Matias Bjørling]

On 4/23/18 10:45 PM, Hans Holmberg wrote:
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> This patch series fixes the(currently incomplete) write error handling
> in pblk by:
> 
>   * queuing and re-submitting failed writes in the write buffer
>   * evacuating valid data data in lines with write failures, so the
>     chunk(s) with write failures can be reset to a known state by the fw
> 
> Lines with failures in smeta are put back on the free list.
> Failed chunks will be reset on the next use.
> 
> If a write failes in emeta, the lba list is cached so the line can be
> garbage collected without scanning the out-of-band area.
> 
> Changes in V2:
> - Added the recov_writes counter increase to the new path
> - Moved lba list emeta reading during gc to a separate function
> - Allocating the saved lba list with pblk_malloc instead of kmalloc
> - Fixed formatting issues
> - Removed dead code
> 
> Hans Holmberg (3):
>    lightnvm: pblk: rework write error recovery path
>    lightnvm: pblk: garbage collect lines with failed writes
>    lightnvm: pblk: fix smeta write error path
> 
>   drivers/lightnvm/pblk-core.c     |  52 +++++++-
>   drivers/lightnvm/pblk-gc.c       | 102 +++++++++------
>   drivers/lightnvm/pblk-init.c     |  47 ++++---
>   drivers/lightnvm/pblk-rb.c       |  39 ------
>   drivers/lightnvm/pblk-recovery.c |  91 -------------
>   drivers/lightnvm/pblk-rl.c       |  29 ++++-
>   drivers/lightnvm/pblk-sysfs.c    |  15 ++-
>   drivers/lightnvm/pblk-write.c    | 269 ++++++++++++++++++++++++++-------------
>   drivers/lightnvm/pblk.h          |  36 ++++--
>   9 files changed, 384 insertions(+), 296 deletions(-)
> 

Thanks Hans. I've applied 1 & 3. The second did not apply cleanly to 
for-4.18/core. Could you please resend a rebased version?

Re: [PATCH v2 0/3] Rework write error handling in pblk

[Javier Gonzalez]

[-- Attachment #1: Type: text/plain, Size: 2098 bytes --]

> On 28 Apr 2018, at 21.31, Matias Bjørling <mb@lightnvm.io> wrote:
> 
> On 4/23/18 10:45 PM, Hans Holmberg wrote:
>> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
>> This patch series fixes the(currently incomplete) write error handling
>> in pblk by:
>>  * queuing and re-submitting failed writes in the write buffer
>>  * evacuating valid data data in lines with write failures, so the
>>    chunk(s) with write failures can be reset to a known state by the fw
>> Lines with failures in smeta are put back on the free list.
>> Failed chunks will be reset on the next use.
>> If a write failes in emeta, the lba list is cached so the line can be
>> garbage collected without scanning the out-of-band area.
>> Changes in V2:
>> - Added the recov_writes counter increase to the new path
>> - Moved lba list emeta reading during gc to a separate function
>> - Allocating the saved lba list with pblk_malloc instead of kmalloc
>> - Fixed formatting issues
>> - Removed dead code
>> Hans Holmberg (3):
>>   lightnvm: pblk: rework write error recovery path
>>   lightnvm: pblk: garbage collect lines with failed writes
>>   lightnvm: pblk: fix smeta write error path
>>  drivers/lightnvm/pblk-core.c     |  52 +++++++-
>>  drivers/lightnvm/pblk-gc.c       | 102 +++++++++------
>>  drivers/lightnvm/pblk-init.c     |  47 ++++---
>>  drivers/lightnvm/pblk-rb.c       |  39 ------
>>  drivers/lightnvm/pblk-recovery.c |  91 -------------
>>  drivers/lightnvm/pblk-rl.c       |  29 ++++-
>>  drivers/lightnvm/pblk-sysfs.c    |  15 ++-
>>  drivers/lightnvm/pblk-write.c    | 269 ++++++++++++++++++++++++++-------------
>>  drivers/lightnvm/pblk.h          |  36 ++++--
>>  9 files changed, 384 insertions(+), 296 deletions(-)
> 
> Thanks Hans. I've applied 1 & 3. The second did not apply cleanly to for-4.18/core. Could you please resend a rebased version?

Hans' patches apply on top of the fixes I sent this week. I have just
sent the V2 and the patches still apply. You can find them at:
  https://github.com/OpenChannelSSD/linux/tree/for-4.18/pblk

Javier

[-- Attachment #2: Message signed with OpenPGP --]
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Re: [PATCH v2 1/3] lightnvm: pblk: rework write error recovery path

[Javier Gonzalez]

[-- Attachment #1: Type: text/plain, Size: 18480 bytes --]

> On 24 Apr 2018, at 07.45, Hans Holmberg <hans.ml.holmberg@owltronix.com> wrote:
> 
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> The write error recovery path is incomplete, so rework
> the write error recovery handling to do resubmits directly
> from the write buffer.
> 
> When a write error occurs, the remaining sectors in the chunk are
> mapped out and invalidated and the request inserted in a resubmit list.
> 
> The writer thread checks if there are any requests to resubmit,
> scans and invalidates any lbas that have been overwritten by later
> writes and resubmits the failed entries.
> 
> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
> ---
> drivers/lightnvm/pblk-init.c     |   2 +
> drivers/lightnvm/pblk-rb.c       |  39 ------
> drivers/lightnvm/pblk-recovery.c |  91 -------------
> drivers/lightnvm/pblk-write.c    | 267 ++++++++++++++++++++++++++-------------
> drivers/lightnvm/pblk.h          |  11 +-
> 5 files changed, 181 insertions(+), 229 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index bfc488d..6f06727 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -426,6 +426,7 @@ static int pblk_core_init(struct pblk *pblk)
> 		goto free_r_end_wq;
> 
> 	INIT_LIST_HEAD(&pblk->compl_list);
> +	INIT_LIST_HEAD(&pblk->resubmit_list);
> 
> 	return 0;
> 
> @@ -1185,6 +1186,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
> 	pblk->state = PBLK_STATE_RUNNING;
> 	pblk->gc.gc_enabled = 0;
> 
> +	spin_lock_init(&pblk->resubmit_lock);
> 	spin_lock_init(&pblk->trans_lock);
> 	spin_lock_init(&pblk->lock);
> 
> diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
> index 024a366..00cd1f2 100644
> --- a/drivers/lightnvm/pblk-rb.c
> +++ b/drivers/lightnvm/pblk-rb.c
> @@ -503,45 +503,6 @@ int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries,
> }
> 
> /*
> - * The caller of this function must ensure that the backpointer will not
> - * overwrite the entries passed on the list.
> - */
> -unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio,
> -				      struct list_head *list,
> -				      unsigned int max)
> -{
> -	struct pblk_rb_entry *entry, *tentry;
> -	struct page *page;
> -	unsigned int read = 0;
> -	int ret;
> -
> -	list_for_each_entry_safe(entry, tentry, list, index) {
> -		if (read > max) {
> -			pr_err("pblk: too many entries on list\n");
> -			goto out;
> -		}
> -
> -		page = virt_to_page(entry->data);
> -		if (!page) {
> -			pr_err("pblk: could not allocate write bio page\n");
> -			goto out;
> -		}
> -
> -		ret = bio_add_page(bio, page, rb->seg_size, 0);
> -		if (ret != rb->seg_size) {
> -			pr_err("pblk: could not add page to write bio\n");
> -			goto out;
> -		}
> -
> -		list_del(&entry->index);
> -		read++;
> -	}
> -
> -out:
> -	return read;
> -}
> -
> -/*
>  * Read available entries on rb and add them to the given bio. To avoid a memory
>  * copy, a page reference to the write buffer is used to be added to the bio.
>  *
> diff --git a/drivers/lightnvm/pblk-recovery.c b/drivers/lightnvm/pblk-recovery.c
> index 9cb6d5d..5983428 100644
> --- a/drivers/lightnvm/pblk-recovery.c
> +++ b/drivers/lightnvm/pblk-recovery.c
> @@ -16,97 +16,6 @@
> 
> #include "pblk.h"
> 
> -void pblk_submit_rec(struct work_struct *work)
> -{
> -	struct pblk_rec_ctx *recovery =
> -			container_of(work, struct pblk_rec_ctx, ws_rec);
> -	struct pblk *pblk = recovery->pblk;
> -	struct nvm_rq *rqd = recovery->rqd;
> -	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
> -	struct bio *bio;
> -	unsigned int nr_rec_secs;
> -	unsigned int pgs_read;
> -	int ret;
> -
> -	nr_rec_secs = bitmap_weight((unsigned long int *)&rqd->ppa_status,
> -								NVM_MAX_VLBA);
> -
> -	bio = bio_alloc(GFP_KERNEL, nr_rec_secs);
> -
> -	bio->bi_iter.bi_sector = 0;
> -	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
> -	rqd->bio = bio;
> -	rqd->nr_ppas = nr_rec_secs;
> -
> -	pgs_read = pblk_rb_read_to_bio_list(&pblk->rwb, bio, &recovery->failed,
> -								nr_rec_secs);
> -	if (pgs_read != nr_rec_secs) {
> -		pr_err("pblk: could not read recovery entries\n");
> -		goto err;
> -	}
> -
> -	if (pblk_setup_w_rec_rq(pblk, rqd, c_ctx)) {
> -		pr_err("pblk: could not setup recovery request\n");
> -		goto err;
> -	}
> -
> -#ifdef CONFIG_NVM_DEBUG
> -	atomic_long_add(nr_rec_secs, &pblk->recov_writes);
> -#endif
> -
> -	ret = pblk_submit_io(pblk, rqd);
> -	if (ret) {
> -		pr_err("pblk: I/O submission failed: %d\n", ret);
> -		goto err;
> -	}
> -
> -	mempool_free(recovery, pblk->rec_pool);
> -	return;
> -
> -err:
> -	bio_put(bio);
> -	pblk_free_rqd(pblk, rqd, PBLK_WRITE);
> -}
> -
> -int pblk_recov_setup_rq(struct pblk *pblk, struct pblk_c_ctx *c_ctx,
> -			struct pblk_rec_ctx *recovery, u64 *comp_bits,
> -			unsigned int comp)
> -{
> -	struct nvm_rq *rec_rqd;
> -	struct pblk_c_ctx *rec_ctx;
> -	int nr_entries = c_ctx->nr_valid + c_ctx->nr_padded;
> -
> -	rec_rqd = pblk_alloc_rqd(pblk, PBLK_WRITE);
> -	rec_ctx = nvm_rq_to_pdu(rec_rqd);
> -
> -	/* Copy completion bitmap, but exclude the first X completed entries */
> -	bitmap_shift_right((unsigned long int *)&rec_rqd->ppa_status,
> -				(unsigned long int *)comp_bits,
> -				comp, NVM_MAX_VLBA);
> -
> -	/* Save the context for the entries that need to be re-written and
> -	 * update current context with the completed entries.
> -	 */
> -	rec_ctx->sentry = pblk_rb_wrap_pos(&pblk->rwb, c_ctx->sentry + comp);
> -	if (comp >= c_ctx->nr_valid) {
> -		rec_ctx->nr_valid = 0;
> -		rec_ctx->nr_padded = nr_entries - comp;
> -
> -		c_ctx->nr_padded = comp - c_ctx->nr_valid;
> -	} else {
> -		rec_ctx->nr_valid = c_ctx->nr_valid - comp;
> -		rec_ctx->nr_padded = c_ctx->nr_padded;
> -
> -		c_ctx->nr_valid = comp;
> -		c_ctx->nr_padded = 0;
> -	}
> -
> -	recovery->rqd = rec_rqd;
> -	recovery->pblk = pblk;
> -
> -	return 0;
> -}
> -
> int pblk_recov_check_emeta(struct pblk *pblk, struct line_emeta *emeta_buf)
> {
> 	u32 crc;
> diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
> index 3e6f1eb..f62e432f 100644
> --- a/drivers/lightnvm/pblk-write.c
> +++ b/drivers/lightnvm/pblk-write.c
> @@ -103,68 +103,149 @@ static void pblk_complete_write(struct pblk *pblk, struct nvm_rq *rqd,
> 	pblk_rb_sync_end(&pblk->rwb, &flags);
> }
> 
> -/* When a write fails, we are not sure whether the block has grown bad or a page
> - * range is more susceptible to write errors. If a high number of pages fail, we
> - * assume that the block is bad and we mark it accordingly. In all cases, we
> - * remap and resubmit the failed entries as fast as possible; if a flush is
> - * waiting on a completion, the whole stack would stall otherwise.
> - */
> -static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
> +/* Map remaining sectors in chunk, starting from ppa */
> +static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
> {
> -	void *comp_bits = &rqd->ppa_status;
> -	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
> -	struct pblk_rec_ctx *recovery;
> -	struct ppa_addr *ppa_list = rqd->ppa_list;
> -	int nr_ppas = rqd->nr_ppas;
> -	unsigned int c_entries;
> -	int bit, ret;
> +	struct nvm_tgt_dev *dev = pblk->dev;
> +	struct nvm_geo *geo = &dev->geo;
> +	struct pblk_line *line;
> +	struct ppa_addr map_ppa = *ppa;
> +	u64 paddr;
> +	int done = 0;
> 
> -	if (unlikely(nr_ppas == 1))
> -		ppa_list = &rqd->ppa_addr;
> +	line = &pblk->lines[pblk_ppa_to_line(*ppa)];
> +	spin_lock(&line->lock);
> 
> -	recovery = mempool_alloc(pblk->rec_pool, GFP_ATOMIC);
> +	while (!done)  {
> +		paddr = pblk_dev_ppa_to_line_addr(pblk, map_ppa);
> 
> -	INIT_LIST_HEAD(&recovery->failed);
> +		if (!test_and_set_bit(paddr, line->map_bitmap))
> +			line->left_msecs--;
> 
> -	bit = -1;
> -	while ((bit = find_next_bit(comp_bits, nr_ppas, bit + 1)) < nr_ppas) {
> -		struct pblk_rb_entry *entry;
> -		struct ppa_addr ppa;
> +		if (!test_and_set_bit(paddr, line->invalid_bitmap))
> +			le32_add_cpu(line->vsc, -1);
> 
> -		/* Logic error */
> -		if (bit > c_ctx->nr_valid) {
> -			WARN_ONCE(1, "pblk: corrupted write request\n");
> -			mempool_free(recovery, pblk->rec_pool);
> -			goto out;
> +		if (geo->version == NVM_OCSSD_SPEC_12) {
> +			map_ppa.ppa++;
> +			if (map_ppa.g.pg == geo->num_pg)
> +				done = 1;
> +		} else {
> +			map_ppa.m.sec++;
> +			if (map_ppa.m.sec == geo->clba)
> +				done = 1;
> 		}
> +	}
> 
> -		ppa = ppa_list[bit];
> -		entry = pblk_rb_sync_scan_entry(&pblk->rwb, &ppa);
> -		if (!entry) {
> -			pr_err("pblk: could not scan entry on write failure\n");
> -			mempool_free(recovery, pblk->rec_pool);
> -			goto out;
> -		}
> +	spin_unlock(&line->lock);
> +}
> +
> +static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
> +				  unsigned int nr_entries)
> +{
> +	struct pblk_rb *rb = &pblk->rwb;
> +	struct pblk_rb_entry *entry;
> +	struct pblk_line *line;
> +	struct pblk_w_ctx *w_ctx;
> +	struct ppa_addr ppa_l2p;
> +	int flags;
> +	unsigned int pos, i;
> +
> +	spin_lock(&pblk->trans_lock);
> +	pos = sentry;
> +	for (i = 0; i < nr_entries; i++) {
> +		entry = &rb->entries[pos];
> +		w_ctx = &entry->w_ctx;
> +
> +		/* Check if the lba has been overwritten */
> +		ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
> +		if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
> +			w_ctx->lba = ADDR_EMPTY;
> +
> +		/* Mark up the entry as submittable again */
> +		flags = READ_ONCE(w_ctx->flags);
> +		flags |= PBLK_WRITTEN_DATA;
> +		/* Release flags on write context. Protect from writes */
> +		smp_store_release(&w_ctx->flags, flags);
> 
> -		/* The list is filled first and emptied afterwards. No need for
> -		 * protecting it with a lock
> +		/* Decrese the reference count to the line as we will
> +		 * re-map these entries
> 		 */
> -		list_add_tail(&entry->index, &recovery->failed);
> +		line = &pblk->lines[pblk_ppa_to_line(w_ctx->ppa)];
> +		kref_put(&line->ref, pblk_line_put);
> +
> +		pos = (pos + 1) & (rb->nr_entries - 1);
> 	}
> +	spin_unlock(&pblk->trans_lock);
> +}
> 
> -	c_entries = find_first_bit(comp_bits, nr_ppas);
> -	ret = pblk_recov_setup_rq(pblk, c_ctx, recovery, comp_bits, c_entries);
> -	if (ret) {
> -		pr_err("pblk: could not recover from write failure\n");
> -		mempool_free(recovery, pblk->rec_pool);
> -		goto out;
> +static void pblk_queue_resubmit(struct pblk *pblk, struct pblk_c_ctx *c_ctx)
> +{
> +	struct pblk_c_ctx *r_ctx;
> +
> +	r_ctx = kzalloc(sizeof(struct pblk_c_ctx), GFP_KERNEL);
> +	if (!r_ctx)
> +		return;
> +
> +	r_ctx->lun_bitmap = NULL;
> +	r_ctx->sentry = c_ctx->sentry;
> +	r_ctx->nr_valid = c_ctx->nr_valid;
> +	r_ctx->nr_padded = c_ctx->nr_padded;
> +
> +	spin_lock(&pblk->resubmit_lock);
> +	list_add_tail(&r_ctx->list, &pblk->resubmit_list);
> +	spin_unlock(&pblk->resubmit_lock);
> +
> +#ifdef CONFIG_NVM_DEBUG
> +	atomic_long_add(c_ctx->nr_valid, &pblk->recov_writes);
> +#endif
> +}
> +
> +static void pblk_submit_rec(struct work_struct *work)
> +{
> +	struct pblk_rec_ctx *recovery =
> +			container_of(work, struct pblk_rec_ctx, ws_rec);
> +	struct pblk *pblk = recovery->pblk;
> +	struct nvm_rq *rqd = recovery->rqd;
> +	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
> +	struct ppa_addr *ppa_list;
> +
> +	pblk_log_write_err(pblk, rqd);
> +
> +	if (rqd->nr_ppas == 1)
> +		ppa_list = &rqd->ppa_addr;
> +	else
> +		ppa_list = rqd->ppa_list;
> +
> +	pblk_map_remaining(pblk, ppa_list);
> +	pblk_queue_resubmit(pblk, c_ctx);
> +
> +	pblk_up_rq(pblk, rqd->ppa_list, rqd->nr_ppas, c_ctx->lun_bitmap);
> +	if (c_ctx->nr_padded)
> +		pblk_bio_free_pages(pblk, rqd->bio, c_ctx->nr_valid,
> +							c_ctx->nr_padded);
> +	bio_put(rqd->bio);
> +	pblk_free_rqd(pblk, rqd, PBLK_WRITE);
> +	mempool_free(recovery, pblk->rec_pool);
> +
> +	atomic_dec(&pblk->inflight_io);
> +}
> +
> +
> +static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
> +{
> +	struct pblk_rec_ctx *recovery;
> +
> +	recovery = mempool_alloc(pblk->rec_pool, GFP_ATOMIC);
> +	if (!recovery) {
> +		pr_err("pblk: could not allocate recovery work\n");
> +		return;
> 	}
> 
> +	recovery->pblk = pblk;
> +	recovery->rqd = rqd;
> +
> 	INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
> 	queue_work(pblk->close_wq, &recovery->ws_rec);
> -
> -out:
> -	pblk_complete_write(pblk, rqd, c_ctx);
> }
> 
> static void pblk_end_io_write(struct nvm_rq *rqd)
> @@ -173,8 +254,8 @@ static void pblk_end_io_write(struct nvm_rq *rqd)
> 	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
> 
> 	if (rqd->error) {
> -		pblk_log_write_err(pblk, rqd);
> -		return pblk_end_w_fail(pblk, rqd);
> +		pblk_end_w_fail(pblk, rqd);
> +		return;
> 	}
> #ifdef CONFIG_NVM_DEBUG
> 	else
> @@ -266,31 +347,6 @@ static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
> 	return 0;
> }
> 
> -int pblk_setup_w_rec_rq(struct pblk *pblk, struct nvm_rq *rqd,
> -			struct pblk_c_ctx *c_ctx)
> -{
> -	struct pblk_line_meta *lm = &pblk->lm;
> -	unsigned long *lun_bitmap;
> -	int ret;
> -
> -	lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
> -	if (!lun_bitmap)
> -		return -ENOMEM;
> -
> -	c_ctx->lun_bitmap = lun_bitmap;
> -
> -	ret = pblk_alloc_w_rq(pblk, rqd, rqd->nr_ppas, pblk_end_io_write);
> -	if (ret)
> -		return ret;
> -
> -	pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, c_ctx->nr_valid, 0);
> -
> -	rqd->ppa_status = (u64)0;
> -	rqd->flags = pblk_set_progr_mode(pblk, PBLK_WRITE);
> -
> -	return ret;
> -}
> -
> static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
> 				  unsigned int secs_to_flush)
> {
> @@ -339,6 +395,7 @@ int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
> 	bio = pblk_bio_map_addr(pblk, data, rq_ppas, rq_len,
> 					l_mg->emeta_alloc_type, GFP_KERNEL);
> 	if (IS_ERR(bio)) {
> +		pr_err("pblk: failed to map emeta io");
> 		ret = PTR_ERR(bio);
> 		goto fail_free_rqd;
> 	}
> @@ -515,26 +572,54 @@ static int pblk_submit_write(struct pblk *pblk)
> 	unsigned int secs_avail, secs_to_sync, secs_to_com;
> 	unsigned int secs_to_flush;
> 	unsigned long pos;
> +	unsigned int resubmit;
> 
> -	/* If there are no sectors in the cache, flushes (bios without data)
> -	 * will be cleared on the cache threads
> -	 */
> -	secs_avail = pblk_rb_read_count(&pblk->rwb);
> -	if (!secs_avail)
> -		return 1;
> -
> -	secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
> -	if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
> -		return 1;
> -
> -	secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail, secs_to_flush);
> -	if (secs_to_sync > pblk->max_write_pgs) {
> -		pr_err("pblk: bad buffer sync calculation\n");
> -		return 1;
> -	}
> +	spin_lock(&pblk->resubmit_lock);
> +	resubmit = !list_empty(&pblk->resubmit_list);
> +	spin_unlock(&pblk->resubmit_lock);
> +
> +	/* Resubmit failed writes first */
> +	if (resubmit) {
> +		struct pblk_c_ctx *r_ctx;
> +
> +		spin_lock(&pblk->resubmit_lock);
> +		r_ctx = list_first_entry(&pblk->resubmit_list,
> +					struct pblk_c_ctx, list);
> +		list_del(&r_ctx->list);
> +		spin_unlock(&pblk->resubmit_lock);
> +
> +		secs_avail = r_ctx->nr_valid;
> +		pos = r_ctx->sentry;
> +
> +		pblk_prepare_resubmit(pblk, pos, secs_avail);
> +		secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
> +				secs_avail);
> 
> -	secs_to_com = (secs_to_sync > secs_avail) ? secs_avail : secs_to_sync;
> -	pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
> +		kfree(r_ctx);
> +	} else {
> +		/* If there are no sectors in the cache,
> +		 * flushes (bios without data) will be cleared on
> +		 * the cache threads
> +		 */
> +		secs_avail = pblk_rb_read_count(&pblk->rwb);
> +		if (!secs_avail)
> +			return 1;
> +
> +		secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
> +		if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
> +			return 1;
> +
> +		secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail,
> +					secs_to_flush);
> +		if (secs_to_sync > pblk->max_write_pgs) {
> +			pr_err("pblk: bad buffer sync calculation\n");
> +			return 1;
> +		}
> +
> +		secs_to_com = (secs_to_sync > secs_avail) ?
> +			secs_avail : secs_to_sync;
> +		pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
> +	}
> 
> 	bio = bio_alloc(GFP_KERNEL, secs_to_sync);
> 
> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
> index 9838d03..f8434a3 100644
> --- a/drivers/lightnvm/pblk.h
> +++ b/drivers/lightnvm/pblk.h
> @@ -128,7 +128,6 @@ struct pblk_pad_rq {
> struct pblk_rec_ctx {
> 	struct pblk *pblk;
> 	struct nvm_rq *rqd;
> -	struct list_head failed;
> 	struct work_struct ws_rec;
> };
> 
> @@ -664,6 +663,9 @@ struct pblk {
> 
> 	struct list_head compl_list;
> 
> +	spinlock_t resubmit_lock;	 /* Resubmit list lock */
> +	struct list_head resubmit_list; /* Resubmit list for failed writes*/
> +
> 	mempool_t *page_bio_pool;
> 	mempool_t *gen_ws_pool;
> 	mempool_t *rec_pool;
> @@ -713,9 +715,6 @@ void pblk_rb_sync_l2p(struct pblk_rb *rb);
> unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd,
> 				 unsigned int pos, unsigned int nr_entries,
> 				 unsigned int count);
> -unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio,
> -				      struct list_head *list,
> -				      unsigned int max);
> int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba,
> 			struct ppa_addr ppa, int bio_iter, bool advanced_bio);
> unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int entries);
> @@ -849,13 +848,9 @@ int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq);
> /*
>  * pblk recovery
>  */
> -void pblk_submit_rec(struct work_struct *work);
> struct pblk_line *pblk_recov_l2p(struct pblk *pblk);
> int pblk_recov_pad(struct pblk *pblk);
> int pblk_recov_check_emeta(struct pblk *pblk, struct line_emeta *emeta);
> -int pblk_recov_setup_rq(struct pblk *pblk, struct pblk_c_ctx *c_ctx,
> -			struct pblk_rec_ctx *recovery, u64 *comp_bits,
> -			unsigned int comp);
> 
> /*
>  * pblk gc
> --
> 2.7.4

LGTM

Reviewed-by: Javier González <javier@cnexlabs.com>


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Re: [PATCH v2 2/3] lightnvm: pblk: garbage collect lines with failed writes

[Javier Gonzalez]

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> On 24 Apr 2018, at 07.45, Hans Holmberg <hans.ml.holmberg@owltronix.com> wrote:
> 
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> Write failures should not happen under normal circumstances,
> so in order to bring the chunk back into a known state as soon
> as possible, evacuate all the valid data out of the line and let the
> fw judge if the block can be written to in the next reset cycle.
> 
> Do this by introducing a new gc list for lines with failed writes,
> and ensure that the rate limiter allocates a small portion of
> the write bandwidth to get the job done.
> 
> The lba list is saved in memory for use during gc as we
> cannot gurantee that the emeta data is readable if a write
> error occurred.
> 
> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
> ---
> drivers/lightnvm/pblk-core.c  |  45 ++++++++++++++++++-
> drivers/lightnvm/pblk-gc.c    | 102 +++++++++++++++++++++++++++---------------
> drivers/lightnvm/pblk-init.c  |  45 ++++++++++++-------
> drivers/lightnvm/pblk-rl.c    |  29 ++++++++++--
> drivers/lightnvm/pblk-sysfs.c |  15 ++++++-
> drivers/lightnvm/pblk-write.c |   2 +
> drivers/lightnvm/pblk.h       |  25 +++++++++--
> 7 files changed, 199 insertions(+), 64 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index 7762e89..413cf3b 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -373,7 +373,13 @@ struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line)
> 
> 	lockdep_assert_held(&line->lock);
> 
> -	if (!vsc) {
> +	if (line->w_err_gc->has_write_err) {
> +		if (line->gc_group != PBLK_LINEGC_WERR) {
> +			line->gc_group = PBLK_LINEGC_WERR;
> +			move_list = &l_mg->gc_werr_list;
> +			pblk_rl_werr_line_in(&pblk->rl);
> +		}
> +	} else if (!vsc) {
> 		if (line->gc_group != PBLK_LINEGC_FULL) {
> 			line->gc_group = PBLK_LINEGC_FULL;
> 			move_list = &l_mg->gc_full_list;
> @@ -1603,8 +1609,13 @@ static void __pblk_line_put(struct pblk *pblk, struct pblk_line *line)
> 	line->state = PBLK_LINESTATE_FREE;
> 	line->gc_group = PBLK_LINEGC_NONE;
> 	pblk_line_free(line);
> -	spin_unlock(&line->lock);
> 
> +	if (line->w_err_gc->has_write_err) {
> +		pblk_rl_werr_line_out(&pblk->rl);
> +		line->w_err_gc->has_write_err = 0;
> +	}
> +
> +	spin_unlock(&line->lock);
> 	atomic_dec(&gc->pipeline_gc);
> 
> 	spin_lock(&l_mg->free_lock);
> @@ -1767,11 +1778,34 @@ void pblk_line_close_meta(struct pblk *pblk, struct pblk_line *line)
> 
> 	spin_lock(&l_mg->close_lock);
> 	spin_lock(&line->lock);
> +
> +	/* Update the in-memory start address for emeta, in case it has
> +	 * shifted due to write errors
> +	 */
> +	if (line->emeta_ssec != line->cur_sec)
> +		line->emeta_ssec = line->cur_sec;
> +
> 	list_add_tail(&line->list, &l_mg->emeta_list);
> 	spin_unlock(&line->lock);
> 	spin_unlock(&l_mg->close_lock);
> 
> 	pblk_line_should_sync_meta(pblk);
> +
> +
> +}
> +
> +static void pblk_save_lba_list(struct pblk *pblk, struct pblk_line *line)
> +{
> +	struct pblk_line_meta *lm = &pblk->lm;
> +	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
> +	unsigned int lba_list_size = lm->emeta_len[2];
> +	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
> +	struct pblk_emeta *emeta = line->emeta;
> +
> +	w_err_gc->lba_list = pblk_malloc(lba_list_size,
> +					 l_mg->emeta_alloc_type, GFP_KERNEL);
> +	memcpy(w_err_gc->lba_list, emeta_to_lbas(pblk, emeta->buf),
> +				lba_list_size);
> }
> 
> void pblk_line_close_ws(struct work_struct *work)
> @@ -1780,6 +1814,13 @@ void pblk_line_close_ws(struct work_struct *work)
> 									ws);
> 	struct pblk *pblk = line_ws->pblk;
> 	struct pblk_line *line = line_ws->line;
> +	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
> +
> +	/* Write errors makes the emeta start address stored in smeta invalid,
> +	 * so keep a copy of the lba list until we've gc'd the line
> +	 */
> +	if (w_err_gc->has_write_err)
> +		pblk_save_lba_list(pblk, line);
> 
> 	pblk_line_close(pblk, line);
> 	mempool_free(line_ws, pblk->gen_ws_pool);
> diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
> index b0cc277..df88f1b 100644
> --- a/drivers/lightnvm/pblk-gc.c
> +++ b/drivers/lightnvm/pblk-gc.c
> @@ -129,6 +129,53 @@ static void pblk_gc_line_ws(struct work_struct *work)
> 	kfree(gc_rq_ws);
> }
> 
> +static __le64 *get_lba_list_from_emeta(struct pblk *pblk,
> +				       struct pblk_line *line)
> +{
> +	struct line_emeta *emeta_buf;
> +	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
> +	struct pblk_line_meta *lm = &pblk->lm;
> +	unsigned int lba_list_size = lm->emeta_len[2];
> +	__le64 *lba_list;
> +	int ret;
> +
> +	emeta_buf = pblk_malloc(lm->emeta_len[0],
> +				l_mg->emeta_alloc_type, GFP_KERNEL);
> +	if (!emeta_buf)
> +		return NULL;
> +
> +	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
> +	if (ret) {
> +		pr_err("pblk: line %d read emeta failed (%d)\n",
> +				line->id, ret);
> +		pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
> +		return NULL;
> +	}
> +
> +	/* If this read fails, it means that emeta is corrupted.
> +	 * For now, leave the line untouched.
> +	 * TODO: Implement a recovery routine that scans and moves
> +	 * all sectors on the line.
> +	 */
> +
> +	ret = pblk_recov_check_emeta(pblk, emeta_buf);
> +	if (ret) {
> +		pr_err("pblk: inconsistent emeta (line %d)\n",
> +				line->id);
> +		pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
> +		return NULL;
> +	}
> +
> +	lba_list = pblk_malloc(lba_list_size,
> +			       l_mg->emeta_alloc_type, GFP_KERNEL);
> +	if (lba_list)
> +		memcpy(lba_list, emeta_to_lbas(pblk, emeta_buf), lba_list_size);
> +
> +	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
> +
> +	return lba_list;
> +}
> +
> static void pblk_gc_line_prepare_ws(struct work_struct *work)
> {
> 	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
> @@ -138,46 +185,26 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
> 	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
> 	struct pblk_line_meta *lm = &pblk->lm;
> 	struct pblk_gc *gc = &pblk->gc;
> -	struct line_emeta *emeta_buf;
> 	struct pblk_line_ws *gc_rq_ws;
> 	struct pblk_gc_rq *gc_rq;
> 	__le64 *lba_list;
> 	unsigned long *invalid_bitmap;
> 	int sec_left, nr_secs, bit;
> -	int ret;
> 
> 	invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_KERNEL);
> 	if (!invalid_bitmap)
> 		goto fail_free_ws;
> 
> -	emeta_buf = pblk_malloc(lm->emeta_len[0], l_mg->emeta_alloc_type,
> -								GFP_KERNEL);
> -	if (!emeta_buf) {
> -		pr_err("pblk: cannot use GC emeta\n");
> -		goto fail_free_bitmap;
> -	}
> -
> -	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
> -	if (ret) {
> -		pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
> -		goto fail_free_emeta;
> -	}
> -
> -	/* If this read fails, it means that emeta is corrupted. For now, leave
> -	 * the line untouched. TODO: Implement a recovery routine that scans and
> -	 * moves all sectors on the line.
> -	 */
> -
> -	ret = pblk_recov_check_emeta(pblk, emeta_buf);
> -	if (ret) {
> -		pr_err("pblk: inconsistent emeta (line %d)\n", line->id);
> -		goto fail_free_emeta;
> -	}
> -
> -	lba_list = emeta_to_lbas(pblk, emeta_buf);
> -	if (!lba_list) {
> -		pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
> -		goto fail_free_emeta;
> +	if (line->w_err_gc->has_write_err) {
> +		lba_list = line->w_err_gc->lba_list;
> +		line->w_err_gc->lba_list = NULL;
> +	} else {
> +		lba_list = get_lba_list_from_emeta(pblk, line);
> +		if (!lba_list) {
> +			pr_err("pblk: could not interpret emeta (line %d)\n",
> +					line->id);
> +			goto fail_free_ws;
> +		}
> 	}
> 
> 	spin_lock(&line->lock);
> @@ -187,14 +214,14 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
> 
> 	if (sec_left < 0) {
> 		pr_err("pblk: corrupted GC line (%d)\n", line->id);
> -		goto fail_free_emeta;
> +		goto fail_free_lba_list;
> 	}
> 
> 	bit = -1;
> next_rq:
> 	gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
> 	if (!gc_rq)
> -		goto fail_free_emeta;
> +		goto fail_free_lba_list;
> 
> 	nr_secs = 0;
> 	do {
> @@ -240,7 +267,7 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
> 		goto next_rq;
> 
> out:
> -	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
> +	pblk_mfree(lba_list, l_mg->emeta_alloc_type);
> 	kfree(line_ws);
> 	kfree(invalid_bitmap);
> 
> @@ -251,9 +278,8 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
> 
> fail_free_gc_rq:
> 	kfree(gc_rq);
> -fail_free_emeta:
> -	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
> -fail_free_bitmap:
> +fail_free_lba_list:
> +	pblk_mfree(lba_list, l_mg->emeta_alloc_type);
> 	kfree(invalid_bitmap);
> fail_free_ws:
> 	kfree(line_ws);
> @@ -349,12 +375,14 @@ static struct pblk_line *pblk_gc_get_victim_line(struct pblk *pblk,
> static bool pblk_gc_should_run(struct pblk_gc *gc, struct pblk_rl *rl)
> {
> 	unsigned int nr_blocks_free, nr_blocks_need;
> +	unsigned int werr_lines = atomic_read(&rl->werr_lines);
> 
> 	nr_blocks_need = pblk_rl_high_thrs(rl);
> 	nr_blocks_free = pblk_rl_nr_free_blks(rl);
> 
> 	/* This is not critical, no need to take lock here */
> -	return ((gc->gc_active) && (nr_blocks_need > nr_blocks_free));
> +	return ((werr_lines > 0) ||
> +		((gc->gc_active) && (nr_blocks_need > nr_blocks_free)));
> }
> 
> void pblk_gc_free_full_lines(struct pblk *pblk)
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index 6f06727..931ba32 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -493,11 +493,16 @@ static void pblk_line_mg_free(struct pblk *pblk)
> 	}
> }
> 
> -static void pblk_line_meta_free(struct pblk_line *line)
> +static void pblk_line_meta_free(struct pblk_line_mgmt *l_mg, struct pblk_line *line)
> {
> +	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
> +
> 	kfree(line->blk_bitmap);
> 	kfree(line->erase_bitmap);
> 	kfree(line->chks);
> +
> +	pblk_mfree(w_err_gc->lba_list, l_mg->emeta_alloc_type);
> +	kfree(w_err_gc);
> }
> 
> static void pblk_lines_free(struct pblk *pblk)
> @@ -511,7 +516,7 @@ static void pblk_lines_free(struct pblk *pblk)
> 		line = &pblk->lines[i];
> 
> 		pblk_line_free(line);
> -		pblk_line_meta_free(line);
> +		pblk_line_meta_free(l_mg, line);
> 	}
> 	spin_unlock(&l_mg->free_lock);
> 
> @@ -813,20 +818,28 @@ static int pblk_alloc_line_meta(struct pblk *pblk, struct pblk_line *line)
> 		return -ENOMEM;
> 
> 	line->erase_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
> -	if (!line->erase_bitmap) {
> -		kfree(line->blk_bitmap);
> -		return -ENOMEM;
> -	}
> +	if (!line->erase_bitmap)
> +		goto free_blk_bitmap;
> +
> 
> 	line->chks = kmalloc(lm->blk_per_line * sizeof(struct nvm_chk_meta),
> 								GFP_KERNEL);
> -	if (!line->chks) {
> -		kfree(line->erase_bitmap);
> -		kfree(line->blk_bitmap);
> -		return -ENOMEM;
> -	}
> +	if (!line->chks)
> +		goto free_erase_bitmap;
> +
> +	line->w_err_gc = kzalloc(sizeof(struct pblk_w_err_gc), GFP_KERNEL);
> +	if (!line->w_err_gc)
> +		goto free_chks;
> 
> 	return 0;
> +
> +free_chks:
> +	kfree(line->chks);
> +free_erase_bitmap:
> +	kfree(line->erase_bitmap);
> +free_blk_bitmap:
> +	kfree(line->blk_bitmap);
> +	return -ENOMEM;
> }
> 
> static int pblk_line_mg_init(struct pblk *pblk)
> @@ -851,12 +864,14 @@ static int pblk_line_mg_init(struct pblk *pblk)
> 	INIT_LIST_HEAD(&l_mg->gc_mid_list);
> 	INIT_LIST_HEAD(&l_mg->gc_low_list);
> 	INIT_LIST_HEAD(&l_mg->gc_empty_list);
> +	INIT_LIST_HEAD(&l_mg->gc_werr_list);
> 
> 	INIT_LIST_HEAD(&l_mg->emeta_list);
> 
> -	l_mg->gc_lists[0] = &l_mg->gc_high_list;
> -	l_mg->gc_lists[1] = &l_mg->gc_mid_list;
> -	l_mg->gc_lists[2] = &l_mg->gc_low_list;
> +	l_mg->gc_lists[0] = &l_mg->gc_werr_list;
> +	l_mg->gc_lists[1] = &l_mg->gc_high_list;
> +	l_mg->gc_lists[2] = &l_mg->gc_mid_list;
> +	l_mg->gc_lists[3] = &l_mg->gc_low_list;
> 
> 	spin_lock_init(&l_mg->free_lock);
> 	spin_lock_init(&l_mg->close_lock);
> @@ -1063,7 +1078,7 @@ static int pblk_lines_init(struct pblk *pblk)
> 
> fail_free_lines:
> 	while (--i >= 0)
> -		pblk_line_meta_free(&pblk->lines[i]);
> +		pblk_line_meta_free(l_mg, &pblk->lines[i]);
> 	kfree(pblk->lines);
> fail_free_chunk_meta:
> 	kfree(chunk_meta);
> diff --git a/drivers/lightnvm/pblk-rl.c b/drivers/lightnvm/pblk-rl.c
> index 883a711..6a0616a 100644
> --- a/drivers/lightnvm/pblk-rl.c
> +++ b/drivers/lightnvm/pblk-rl.c
> @@ -73,6 +73,16 @@ void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries)
> 	pblk_rl_kick_u_timer(rl);
> }
> 
> +void pblk_rl_werr_line_in(struct pblk_rl *rl)
> +{
> +	atomic_inc(&rl->werr_lines);
> +}
> +
> +void pblk_rl_werr_line_out(struct pblk_rl *rl)
> +{
> +	atomic_dec(&rl->werr_lines);
> +}
> +
> void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries)
> {
> 	atomic_add(nr_entries, &rl->rb_gc_cnt);
> @@ -99,11 +109,21 @@ static void __pblk_rl_update_rates(struct pblk_rl *rl,
> {
> 	struct pblk *pblk = container_of(rl, struct pblk, rl);
> 	int max = rl->rb_budget;
> +	int werr_gc_needed = atomic_read(&rl->werr_lines);
> 
> 	if (free_blocks >= rl->high) {
> -		rl->rb_user_max = max;
> -		rl->rb_gc_max = 0;
> -		rl->rb_state = PBLK_RL_HIGH;
> +		if (werr_gc_needed) {
> +			/* Allocate a small budget for recovering
> +			 * lines with write errors
> +			 */
> +			rl->rb_gc_max = 1 << rl->rb_windows_pw;
> +			rl->rb_user_max = max - rl->rb_gc_max;
> +			rl->rb_state = PBLK_RL_WERR;
> +		} else {
> +			rl->rb_user_max = max;
> +			rl->rb_gc_max = 0;
> +			rl->rb_state = PBLK_RL_OFF;
> +		}
> 	} else if (free_blocks < rl->high) {
> 		int shift = rl->high_pw - rl->rb_windows_pw;
> 		int user_windows = free_blocks >> shift;
> @@ -124,7 +144,7 @@ static void __pblk_rl_update_rates(struct pblk_rl *rl,
> 		rl->rb_state = PBLK_RL_LOW;
> 	}
> 
> -	if (rl->rb_state == (PBLK_RL_MID | PBLK_RL_LOW))
> +	if (rl->rb_state != PBLK_RL_OFF)
> 		pblk_gc_should_start(pblk);
> 	else
> 		pblk_gc_should_stop(pblk);
> @@ -221,6 +241,7 @@ void pblk_rl_init(struct pblk_rl *rl, int budget)
> 	atomic_set(&rl->rb_user_cnt, 0);
> 	atomic_set(&rl->rb_gc_cnt, 0);
> 	atomic_set(&rl->rb_space, -1);
> +	atomic_set(&rl->werr_lines, 0);
> 
> 	timer_setup(&rl->u_timer, pblk_rl_u_timer, 0);
> 
> diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c
> index e61909a..88a0a7c 100644
> --- a/drivers/lightnvm/pblk-sysfs.c
> +++ b/drivers/lightnvm/pblk-sysfs.c
> @@ -173,6 +173,8 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
> 	int free_line_cnt = 0, closed_line_cnt = 0, emeta_line_cnt = 0;
> 	int d_line_cnt = 0, l_line_cnt = 0;
> 	int gc_full = 0, gc_high = 0, gc_mid = 0, gc_low = 0, gc_empty = 0;
> +	int gc_werr = 0;
> +
> 	int bad = 0, cor = 0;
> 	int msecs = 0, cur_sec = 0, vsc = 0, sec_in_line = 0;
> 	int map_weight = 0, meta_weight = 0;
> @@ -237,6 +239,15 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
> 		gc_empty++;
> 	}
> 
> +	list_for_each_entry(line, &l_mg->gc_werr_list, list) {
> +		if (line->type == PBLK_LINETYPE_DATA)
> +			d_line_cnt++;
> +		else if (line->type == PBLK_LINETYPE_LOG)
> +			l_line_cnt++;
> +		closed_line_cnt++;
> +		gc_werr++;
> +	}
> +
> 	list_for_each_entry(line, &l_mg->bad_list, list)
> 		bad++;
> 	list_for_each_entry(line, &l_mg->corrupt_list, list)
> @@ -275,8 +286,8 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
> 					l_mg->nr_lines);
> 
> 	sz += snprintf(page + sz, PAGE_SIZE - sz,
> -		"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, queue:%d\n",
> -			gc_full, gc_high, gc_mid, gc_low, gc_empty,
> +		"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, werr: %d, queue:%d\n",
> +			gc_full, gc_high, gc_mid, gc_low, gc_empty, gc_werr,
> 			atomic_read(&pblk->gc.read_inflight_gc));
> 
> 	sz += snprintf(page + sz, PAGE_SIZE - sz,
> diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
> index f62e432f..f33c2c3 100644
> --- a/drivers/lightnvm/pblk-write.c
> +++ b/drivers/lightnvm/pblk-write.c
> @@ -136,6 +136,7 @@ static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
> 		}
> 	}
> 
> +	line->w_err_gc->has_write_err = 1;
> 	spin_unlock(&line->lock);
> }
> 
> @@ -279,6 +280,7 @@ static void pblk_end_io_write_meta(struct nvm_rq *rqd)
> 	if (rqd->error) {
> 		pblk_log_write_err(pblk, rqd);
> 		pr_err("pblk: metadata I/O failed. Line %d\n", line->id);
> +		line->w_err_gc->has_write_err = 1;
> 	}
> 
> 	sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
> index f8434a3..25ad026 100644
> --- a/drivers/lightnvm/pblk.h
> +++ b/drivers/lightnvm/pblk.h
> @@ -89,12 +89,14 @@ struct pblk_sec_meta {
> /* The number of GC lists and the rate-limiter states go together. This way the
>  * rate-limiter can dictate how much GC is needed based on resource utilization.
>  */
> -#define PBLK_GC_NR_LISTS 3
> +#define PBLK_GC_NR_LISTS 4
> 
> enum {
> -	PBLK_RL_HIGH = 1,
> -	PBLK_RL_MID = 2,
> -	PBLK_RL_LOW = 3,
> +	PBLK_RL_OFF = 0,
> +	PBLK_RL_WERR = 1,
> +	PBLK_RL_HIGH = 2,
> +	PBLK_RL_MID = 3,
> +	PBLK_RL_LOW = 4
> };
> 
> #define pblk_dma_meta_size (sizeof(struct pblk_sec_meta) * PBLK_MAX_REQ_ADDRS)
> @@ -278,6 +280,8 @@ struct pblk_rl {
> 	int rb_user_active;
> 	int rb_gc_active;
> 
> +	atomic_t werr_lines;	/* Number of write error lines that needs gc */
> +
> 	struct timer_list u_timer;
> 
> 	unsigned long long nr_secs;
> @@ -311,6 +315,7 @@ enum {
> 	PBLK_LINEGC_MID = 23,
> 	PBLK_LINEGC_HIGH = 24,
> 	PBLK_LINEGC_FULL = 25,
> +	PBLK_LINEGC_WERR = 26
> };
> 
> #define PBLK_MAGIC 0x70626c6b /*pblk*/
> @@ -412,6 +417,11 @@ struct pblk_smeta {
> 	struct line_smeta *buf;		/* smeta buffer in persistent format */
> };
> 
> +struct pblk_w_err_gc {
> +	int has_write_err;
> +	__le64 *lba_list;
> +};
> +
> struct pblk_line {
> 	struct pblk *pblk;
> 	unsigned int id;		/* Line number corresponds to the
> @@ -457,6 +467,8 @@ struct pblk_line {
> 
> 	struct kref ref;		/* Write buffer L2P references */
> 
> +	struct pblk_w_err_gc *w_err_gc;	/* Write error gc recovery metadata */
> +
> 	spinlock_t lock;		/* Necessary for invalid_bitmap only */
> };
> 
> @@ -488,6 +500,8 @@ struct pblk_line_mgmt {
> 	struct list_head gc_mid_list;	/* Full lines ready to GC, mid isc */
> 	struct list_head gc_low_list;	/* Full lines ready to GC, low isc */
> 
> +	struct list_head gc_werr_list;  /* Write err recovery list */
> +
> 	struct list_head gc_full_list;	/* Full lines ready to GC, no valid */
> 	struct list_head gc_empty_list;	/* Full lines close, all valid */
> 
> @@ -891,6 +905,9 @@ void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line,
> 			    bool used);
> int pblk_rl_is_limit(struct pblk_rl *rl);
> 
> +void pblk_rl_werr_line_in(struct pblk_rl *rl);
> +void pblk_rl_werr_line_out(struct pblk_rl *rl);
> +
> /*
>  * pblk sysfs
>  */
> --
> 2.7.4

LGTM

Reviewed-by: Javier González <javier@cnexlabs.com>


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Re: [PATCH v2 2/3] lightnvm: pblk: garbage collect lines with failed writes

[Javier Gonzalez]

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> On 30 Apr 2018, at 11.14, Javier Gonzalez <javier@cnexlabs.com> wrote:
> 
>> On 24 Apr 2018, at 07.45, Hans Holmberg <hans.ml.holmberg@owltronix.com> wrote:
>> 
>> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
>> 
>> Write failures should not happen under normal circumstances,
>> so in order to bring the chunk back into a known state as soon
>> as possible, evacuate all the valid data out of the line and let the
>> fw judge if the block can be written to in the next reset cycle.
>> 
>> Do this by introducing a new gc list for lines with failed writes,
>> and ensure that the rate limiter allocates a small portion of
>> the write bandwidth to get the job done.
>> 
>> The lba list is saved in memory for use during gc as we
>> cannot gurantee that the emeta data is readable if a write
>> error occurred.
>> 
>> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
>> ---
>> drivers/lightnvm/pblk-core.c  |  45 ++++++++++++++++++-
>> drivers/lightnvm/pblk-gc.c    | 102 +++++++++++++++++++++++++++---------------
>> drivers/lightnvm/pblk-init.c  |  45 ++++++++++++-------
>> drivers/lightnvm/pblk-rl.c    |  29 ++++++++++--
>> drivers/lightnvm/pblk-sysfs.c |  15 ++++++-
>> drivers/lightnvm/pblk-write.c |   2 +
>> drivers/lightnvm/pblk.h       |  25 +++++++++--
>> 7 files changed, 199 insertions(+), 64 deletions(-)
>> 
>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
>> index 7762e89..413cf3b 100644
>> --- a/drivers/lightnvm/pblk-core.c
>> +++ b/drivers/lightnvm/pblk-core.c
>> @@ -373,7 +373,13 @@ struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line)
>> 
>> 	lockdep_assert_held(&line->lock);
>> 
>> -	if (!vsc) {
>> +	if (line->w_err_gc->has_write_err) {
>> +		if (line->gc_group != PBLK_LINEGC_WERR) {
>> +			line->gc_group = PBLK_LINEGC_WERR;
>> +			move_list = &l_mg->gc_werr_list;
>> +			pblk_rl_werr_line_in(&pblk->rl);
>> +		}
>> +	} else if (!vsc) {
>> 		if (line->gc_group != PBLK_LINEGC_FULL) {
>> 			line->gc_group = PBLK_LINEGC_FULL;
>> 			move_list = &l_mg->gc_full_list;
>> @@ -1603,8 +1609,13 @@ static void __pblk_line_put(struct pblk *pblk, struct pblk_line *line)
>> 	line->state = PBLK_LINESTATE_FREE;
>> 	line->gc_group = PBLK_LINEGC_NONE;
>> 	pblk_line_free(line);
>> -	spin_unlock(&line->lock);
>> 
>> +	if (line->w_err_gc->has_write_err) {
>> +		pblk_rl_werr_line_out(&pblk->rl);
>> +		line->w_err_gc->has_write_err = 0;
>> +	}
>> +
>> +	spin_unlock(&line->lock);
>> 	atomic_dec(&gc->pipeline_gc);
>> 
>> 	spin_lock(&l_mg->free_lock);
>> @@ -1767,11 +1778,34 @@ void pblk_line_close_meta(struct pblk *pblk, struct pblk_line *line)
>> 
>> 	spin_lock(&l_mg->close_lock);
>> 	spin_lock(&line->lock);
>> +
>> +	/* Update the in-memory start address for emeta, in case it has
>> +	 * shifted due to write errors
>> +	 */
>> +	if (line->emeta_ssec != line->cur_sec)
>> +		line->emeta_ssec = line->cur_sec;
>> +
>> 	list_add_tail(&line->list, &l_mg->emeta_list);
>> 	spin_unlock(&line->lock);
>> 	spin_unlock(&l_mg->close_lock);
>> 
>> 	pblk_line_should_sync_meta(pblk);
>> +
>> +
>> +}
>> +
>> +static void pblk_save_lba_list(struct pblk *pblk, struct pblk_line *line)
>> +{
>> +	struct pblk_line_meta *lm = &pblk->lm;
>> +	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
>> +	unsigned int lba_list_size = lm->emeta_len[2];
>> +	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
>> +	struct pblk_emeta *emeta = line->emeta;
>> +
>> +	w_err_gc->lba_list = pblk_malloc(lba_list_size,
>> +					 l_mg->emeta_alloc_type, GFP_KERNEL);
>> +	memcpy(w_err_gc->lba_list, emeta_to_lbas(pblk, emeta->buf),
>> +				lba_list_size);
>> }
>> 
>> void pblk_line_close_ws(struct work_struct *work)
>> @@ -1780,6 +1814,13 @@ void pblk_line_close_ws(struct work_struct *work)
>> 									ws);
>> 	struct pblk *pblk = line_ws->pblk;
>> 	struct pblk_line *line = line_ws->line;
>> +	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
>> +
>> +	/* Write errors makes the emeta start address stored in smeta invalid,
>> +	 * so keep a copy of the lba list until we've gc'd the line
>> +	 */
>> +	if (w_err_gc->has_write_err)
>> +		pblk_save_lba_list(pblk, line);
>> 
>> 	pblk_line_close(pblk, line);
>> 	mempool_free(line_ws, pblk->gen_ws_pool);
>> diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
>> index b0cc277..df88f1b 100644
>> --- a/drivers/lightnvm/pblk-gc.c
>> +++ b/drivers/lightnvm/pblk-gc.c
>> @@ -129,6 +129,53 @@ static void pblk_gc_line_ws(struct work_struct *work)
>> 	kfree(gc_rq_ws);
>> }
>> 
>> +static __le64 *get_lba_list_from_emeta(struct pblk *pblk,
>> +				       struct pblk_line *line)
>> +{
>> +	struct line_emeta *emeta_buf;
>> +	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
>> +	struct pblk_line_meta *lm = &pblk->lm;
>> +	unsigned int lba_list_size = lm->emeta_len[2];
>> +	__le64 *lba_list;
>> +	int ret;
>> +
>> +	emeta_buf = pblk_malloc(lm->emeta_len[0],
>> +				l_mg->emeta_alloc_type, GFP_KERNEL);
>> +	if (!emeta_buf)
>> +		return NULL;
>> +
>> +	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
>> +	if (ret) {
>> +		pr_err("pblk: line %d read emeta failed (%d)\n",
>> +				line->id, ret);
>> +		pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
>> +		return NULL;
>> +	}
>> +
>> +	/* If this read fails, it means that emeta is corrupted.
>> +	 * For now, leave the line untouched.
>> +	 * TODO: Implement a recovery routine that scans and moves
>> +	 * all sectors on the line.
>> +	 */
>> +
>> +	ret = pblk_recov_check_emeta(pblk, emeta_buf);
>> +	if (ret) {
>> +		pr_err("pblk: inconsistent emeta (line %d)\n",
>> +				line->id);
>> +		pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
>> +		return NULL;
>> +	}
>> +
>> +	lba_list = pblk_malloc(lba_list_size,
>> +			       l_mg->emeta_alloc_type, GFP_KERNEL);
>> +	if (lba_list)
>> +		memcpy(lba_list, emeta_to_lbas(pblk, emeta_buf), lba_list_size);
>> +
>> +	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
>> +
>> +	return lba_list;
>> +}
>> +
>> static void pblk_gc_line_prepare_ws(struct work_struct *work)
>> {
>> 	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
>> @@ -138,46 +185,26 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
>> 	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
>> 	struct pblk_line_meta *lm = &pblk->lm;
>> 	struct pblk_gc *gc = &pblk->gc;
>> -	struct line_emeta *emeta_buf;
>> 	struct pblk_line_ws *gc_rq_ws;
>> 	struct pblk_gc_rq *gc_rq;
>> 	__le64 *lba_list;
>> 	unsigned long *invalid_bitmap;
>> 	int sec_left, nr_secs, bit;
>> -	int ret;
>> 
>> 	invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_KERNEL);
>> 	if (!invalid_bitmap)
>> 		goto fail_free_ws;
>> 
>> -	emeta_buf = pblk_malloc(lm->emeta_len[0], l_mg->emeta_alloc_type,
>> -								GFP_KERNEL);
>> -	if (!emeta_buf) {
>> -		pr_err("pblk: cannot use GC emeta\n");
>> -		goto fail_free_bitmap;
>> -	}
>> -
>> -	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
>> -	if (ret) {
>> -		pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
>> -		goto fail_free_emeta;
>> -	}
>> -
>> -	/* If this read fails, it means that emeta is corrupted. For now, leave
>> -	 * the line untouched. TODO: Implement a recovery routine that scans and
>> -	 * moves all sectors on the line.
>> -	 */
>> -
>> -	ret = pblk_recov_check_emeta(pblk, emeta_buf);
>> -	if (ret) {
>> -		pr_err("pblk: inconsistent emeta (line %d)\n", line->id);
>> -		goto fail_free_emeta;
>> -	}
>> -
>> -	lba_list = emeta_to_lbas(pblk, emeta_buf);
>> -	if (!lba_list) {
>> -		pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
>> -		goto fail_free_emeta;
>> +	if (line->w_err_gc->has_write_err) {
>> +		lba_list = line->w_err_gc->lba_list;
>> +		line->w_err_gc->lba_list = NULL;
>> +	} else {
>> +		lba_list = get_lba_list_from_emeta(pblk, line);
>> +		if (!lba_list) {
>> +			pr_err("pblk: could not interpret emeta (line %d)\n",
>> +					line->id);
>> +			goto fail_free_ws;
>> +		}
>> 	}
>> 
>> 	spin_lock(&line->lock);
>> @@ -187,14 +214,14 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
>> 
>> 	if (sec_left < 0) {
>> 		pr_err("pblk: corrupted GC line (%d)\n", line->id);
>> -		goto fail_free_emeta;
>> +		goto fail_free_lba_list;
>> 	}
>> 
>> 	bit = -1;
>> next_rq:
>> 	gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
>> 	if (!gc_rq)
>> -		goto fail_free_emeta;
>> +		goto fail_free_lba_list;
>> 
>> 	nr_secs = 0;
>> 	do {
>> @@ -240,7 +267,7 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
>> 		goto next_rq;
>> 
>> out:
>> -	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
>> +	pblk_mfree(lba_list, l_mg->emeta_alloc_type);
>> 	kfree(line_ws);
>> 	kfree(invalid_bitmap);
>> 
>> @@ -251,9 +278,8 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
>> 
>> fail_free_gc_rq:
>> 	kfree(gc_rq);
>> -fail_free_emeta:
>> -	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
>> -fail_free_bitmap:
>> +fail_free_lba_list:
>> +	pblk_mfree(lba_list, l_mg->emeta_alloc_type);
>> 	kfree(invalid_bitmap);
>> fail_free_ws:
>> 	kfree(line_ws);
>> @@ -349,12 +375,14 @@ static struct pblk_line *pblk_gc_get_victim_line(struct pblk *pblk,
>> static bool pblk_gc_should_run(struct pblk_gc *gc, struct pblk_rl *rl)
>> {
>> 	unsigned int nr_blocks_free, nr_blocks_need;
>> +	unsigned int werr_lines = atomic_read(&rl->werr_lines);
>> 
>> 	nr_blocks_need = pblk_rl_high_thrs(rl);
>> 	nr_blocks_free = pblk_rl_nr_free_blks(rl);
>> 
>> 	/* This is not critical, no need to take lock here */
>> -	return ((gc->gc_active) && (nr_blocks_need > nr_blocks_free));
>> +	return ((werr_lines > 0) ||
>> +		((gc->gc_active) && (nr_blocks_need > nr_blocks_free)));
>> }
>> 
>> void pblk_gc_free_full_lines(struct pblk *pblk)
>> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
>> index 6f06727..931ba32 100644
>> --- a/drivers/lightnvm/pblk-init.c
>> +++ b/drivers/lightnvm/pblk-init.c
>> @@ -493,11 +493,16 @@ static void pblk_line_mg_free(struct pblk *pblk)
>> 	}
>> }
>> 
>> -static void pblk_line_meta_free(struct pblk_line *line)
>> +static void pblk_line_meta_free(struct pblk_line_mgmt *l_mg, struct pblk_line *line)

Actually, this goes over 80 lines - please run checkpatch.

Matias: can you fix this when picking it up? Thanks!


>> {
>> +	struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
>> +
>> 	kfree(line->blk_bitmap);
>> 	kfree(line->erase_bitmap);
>> 	kfree(line->chks);
>> +
>> +	pblk_mfree(w_err_gc->lba_list, l_mg->emeta_alloc_type);
>> +	kfree(w_err_gc);
>> }
>> 
>> static void pblk_lines_free(struct pblk *pblk)
>> @@ -511,7 +516,7 @@ static void pblk_lines_free(struct pblk *pblk)
>> 		line = &pblk->lines[i];
>> 
>> 		pblk_line_free(line);
>> -		pblk_line_meta_free(line);
>> +		pblk_line_meta_free(l_mg, line);
>> 	}
>> 	spin_unlock(&l_mg->free_lock);
>> 
>> @@ -813,20 +818,28 @@ static int pblk_alloc_line_meta(struct pblk *pblk, struct pblk_line *line)
>> 		return -ENOMEM;
>> 
>> 	line->erase_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
>> -	if (!line->erase_bitmap) {
>> -		kfree(line->blk_bitmap);
>> -		return -ENOMEM;
>> -	}
>> +	if (!line->erase_bitmap)
>> +		goto free_blk_bitmap;
>> +
>> 
>> 	line->chks = kmalloc(lm->blk_per_line * sizeof(struct nvm_chk_meta),
>> 								GFP_KERNEL);
>> -	if (!line->chks) {
>> -		kfree(line->erase_bitmap);
>> -		kfree(line->blk_bitmap);
>> -		return -ENOMEM;
>> -	}
>> +	if (!line->chks)
>> +		goto free_erase_bitmap;
>> +
>> +	line->w_err_gc = kzalloc(sizeof(struct pblk_w_err_gc), GFP_KERNEL);
>> +	if (!line->w_err_gc)
>> +		goto free_chks;
>> 
>> 	return 0;
>> +
>> +free_chks:
>> +	kfree(line->chks);
>> +free_erase_bitmap:
>> +	kfree(line->erase_bitmap);
>> +free_blk_bitmap:
>> +	kfree(line->blk_bitmap);
>> +	return -ENOMEM;
>> }
>> 
>> static int pblk_line_mg_init(struct pblk *pblk)
>> @@ -851,12 +864,14 @@ static int pblk_line_mg_init(struct pblk *pblk)
>> 	INIT_LIST_HEAD(&l_mg->gc_mid_list);
>> 	INIT_LIST_HEAD(&l_mg->gc_low_list);
>> 	INIT_LIST_HEAD(&l_mg->gc_empty_list);
>> +	INIT_LIST_HEAD(&l_mg->gc_werr_list);
>> 
>> 	INIT_LIST_HEAD(&l_mg->emeta_list);
>> 
>> -	l_mg->gc_lists[0] = &l_mg->gc_high_list;
>> -	l_mg->gc_lists[1] = &l_mg->gc_mid_list;
>> -	l_mg->gc_lists[2] = &l_mg->gc_low_list;
>> +	l_mg->gc_lists[0] = &l_mg->gc_werr_list;
>> +	l_mg->gc_lists[1] = &l_mg->gc_high_list;
>> +	l_mg->gc_lists[2] = &l_mg->gc_mid_list;
>> +	l_mg->gc_lists[3] = &l_mg->gc_low_list;
>> 
>> 	spin_lock_init(&l_mg->free_lock);
>> 	spin_lock_init(&l_mg->close_lock);
>> @@ -1063,7 +1078,7 @@ static int pblk_lines_init(struct pblk *pblk)
>> 
>> fail_free_lines:
>> 	while (--i >= 0)
>> -		pblk_line_meta_free(&pblk->lines[i]);
>> +		pblk_line_meta_free(l_mg, &pblk->lines[i]);
>> 	kfree(pblk->lines);
>> fail_free_chunk_meta:
>> 	kfree(chunk_meta);
>> diff --git a/drivers/lightnvm/pblk-rl.c b/drivers/lightnvm/pblk-rl.c
>> index 883a711..6a0616a 100644
>> --- a/drivers/lightnvm/pblk-rl.c
>> +++ b/drivers/lightnvm/pblk-rl.c
>> @@ -73,6 +73,16 @@ void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries)
>> 	pblk_rl_kick_u_timer(rl);
>> }
>> 
>> +void pblk_rl_werr_line_in(struct pblk_rl *rl)
>> +{
>> +	atomic_inc(&rl->werr_lines);
>> +}
>> +
>> +void pblk_rl_werr_line_out(struct pblk_rl *rl)
>> +{
>> +	atomic_dec(&rl->werr_lines);
>> +}
>> +
>> void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries)
>> {
>> 	atomic_add(nr_entries, &rl->rb_gc_cnt);
>> @@ -99,11 +109,21 @@ static void __pblk_rl_update_rates(struct pblk_rl *rl,
>> {
>> 	struct pblk *pblk = container_of(rl, struct pblk, rl);
>> 	int max = rl->rb_budget;
>> +	int werr_gc_needed = atomic_read(&rl->werr_lines);
>> 
>> 	if (free_blocks >= rl->high) {
>> -		rl->rb_user_max = max;
>> -		rl->rb_gc_max = 0;
>> -		rl->rb_state = PBLK_RL_HIGH;
>> +		if (werr_gc_needed) {
>> +			/* Allocate a small budget for recovering
>> +			 * lines with write errors
>> +			 */
>> +			rl->rb_gc_max = 1 << rl->rb_windows_pw;
>> +			rl->rb_user_max = max - rl->rb_gc_max;
>> +			rl->rb_state = PBLK_RL_WERR;
>> +		} else {
>> +			rl->rb_user_max = max;
>> +			rl->rb_gc_max = 0;
>> +			rl->rb_state = PBLK_RL_OFF;
>> +		}
>> 	} else if (free_blocks < rl->high) {
>> 		int shift = rl->high_pw - rl->rb_windows_pw;
>> 		int user_windows = free_blocks >> shift;
>> @@ -124,7 +144,7 @@ static void __pblk_rl_update_rates(struct pblk_rl *rl,
>> 		rl->rb_state = PBLK_RL_LOW;
>> 	}
>> 
>> -	if (rl->rb_state == (PBLK_RL_MID | PBLK_RL_LOW))
>> +	if (rl->rb_state != PBLK_RL_OFF)
>> 		pblk_gc_should_start(pblk);
>> 	else
>> 		pblk_gc_should_stop(pblk);
>> @@ -221,6 +241,7 @@ void pblk_rl_init(struct pblk_rl *rl, int budget)
>> 	atomic_set(&rl->rb_user_cnt, 0);
>> 	atomic_set(&rl->rb_gc_cnt, 0);
>> 	atomic_set(&rl->rb_space, -1);
>> +	atomic_set(&rl->werr_lines, 0);
>> 
>> 	timer_setup(&rl->u_timer, pblk_rl_u_timer, 0);
>> 
>> diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c
>> index e61909a..88a0a7c 100644
>> --- a/drivers/lightnvm/pblk-sysfs.c
>> +++ b/drivers/lightnvm/pblk-sysfs.c
>> @@ -173,6 +173,8 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
>> 	int free_line_cnt = 0, closed_line_cnt = 0, emeta_line_cnt = 0;
>> 	int d_line_cnt = 0, l_line_cnt = 0;
>> 	int gc_full = 0, gc_high = 0, gc_mid = 0, gc_low = 0, gc_empty = 0;
>> +	int gc_werr = 0;
>> +
>> 	int bad = 0, cor = 0;
>> 	int msecs = 0, cur_sec = 0, vsc = 0, sec_in_line = 0;
>> 	int map_weight = 0, meta_weight = 0;
>> @@ -237,6 +239,15 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
>> 		gc_empty++;
>> 	}
>> 
>> +	list_for_each_entry(line, &l_mg->gc_werr_list, list) {
>> +		if (line->type == PBLK_LINETYPE_DATA)
>> +			d_line_cnt++;
>> +		else if (line->type == PBLK_LINETYPE_LOG)
>> +			l_line_cnt++;
>> +		closed_line_cnt++;
>> +		gc_werr++;
>> +	}
>> +
>> 	list_for_each_entry(line, &l_mg->bad_list, list)
>> 		bad++;
>> 	list_for_each_entry(line, &l_mg->corrupt_list, list)
>> @@ -275,8 +286,8 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
>> 					l_mg->nr_lines);
>> 
>> 	sz += snprintf(page + sz, PAGE_SIZE - sz,
>> -		"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, queue:%d\n",
>> -			gc_full, gc_high, gc_mid, gc_low, gc_empty,
>> +		"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, werr: %d, queue:%d\n",
>> +			gc_full, gc_high, gc_mid, gc_low, gc_empty, gc_werr,
>> 			atomic_read(&pblk->gc.read_inflight_gc));
>> 
>> 	sz += snprintf(page + sz, PAGE_SIZE - sz,
>> diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
>> index f62e432f..f33c2c3 100644
>> --- a/drivers/lightnvm/pblk-write.c
>> +++ b/drivers/lightnvm/pblk-write.c
>> @@ -136,6 +136,7 @@ static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
>> 		}
>> 	}
>> 
>> +	line->w_err_gc->has_write_err = 1;
>> 	spin_unlock(&line->lock);
>> }
>> 
>> @@ -279,6 +280,7 @@ static void pblk_end_io_write_meta(struct nvm_rq *rqd)
>> 	if (rqd->error) {
>> 		pblk_log_write_err(pblk, rqd);
>> 		pr_err("pblk: metadata I/O failed. Line %d\n", line->id);
>> +		line->w_err_gc->has_write_err = 1;
>> 	}
>> 
>> 	sync = atomic_add_return(rqd->nr_ppas, &emeta->sync);
>> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
>> index f8434a3..25ad026 100644
>> --- a/drivers/lightnvm/pblk.h
>> +++ b/drivers/lightnvm/pblk.h
>> @@ -89,12 +89,14 @@ struct pblk_sec_meta {
>> /* The number of GC lists and the rate-limiter states go together. This way the
>> * rate-limiter can dictate how much GC is needed based on resource utilization.
>> */
>> -#define PBLK_GC_NR_LISTS 3
>> +#define PBLK_GC_NR_LISTS 4
>> 
>> enum {
>> -	PBLK_RL_HIGH = 1,
>> -	PBLK_RL_MID = 2,
>> -	PBLK_RL_LOW = 3,
>> +	PBLK_RL_OFF = 0,
>> +	PBLK_RL_WERR = 1,
>> +	PBLK_RL_HIGH = 2,
>> +	PBLK_RL_MID = 3,
>> +	PBLK_RL_LOW = 4
>> };
>> 
>> #define pblk_dma_meta_size (sizeof(struct pblk_sec_meta) * PBLK_MAX_REQ_ADDRS)
>> @@ -278,6 +280,8 @@ struct pblk_rl {
>> 	int rb_user_active;
>> 	int rb_gc_active;
>> 
>> +	atomic_t werr_lines;	/* Number of write error lines that needs gc */
>> +
>> 	struct timer_list u_timer;
>> 
>> 	unsigned long long nr_secs;
>> @@ -311,6 +315,7 @@ enum {
>> 	PBLK_LINEGC_MID = 23,
>> 	PBLK_LINEGC_HIGH = 24,
>> 	PBLK_LINEGC_FULL = 25,
>> +	PBLK_LINEGC_WERR = 26
>> };
>> 
>> #define PBLK_MAGIC 0x70626c6b /*pblk*/
>> @@ -412,6 +417,11 @@ struct pblk_smeta {
>> 	struct line_smeta *buf;		/* smeta buffer in persistent format */
>> };
>> 
>> +struct pblk_w_err_gc {
>> +	int has_write_err;
>> +	__le64 *lba_list;
>> +};
>> +
>> struct pblk_line {
>> 	struct pblk *pblk;
>> 	unsigned int id;		/* Line number corresponds to the
>> @@ -457,6 +467,8 @@ struct pblk_line {
>> 
>> 	struct kref ref;		/* Write buffer L2P references */
>> 
>> +	struct pblk_w_err_gc *w_err_gc;	/* Write error gc recovery metadata */
>> +
>> 	spinlock_t lock;		/* Necessary for invalid_bitmap only */
>> };
>> 
>> @@ -488,6 +500,8 @@ struct pblk_line_mgmt {
>> 	struct list_head gc_mid_list;	/* Full lines ready to GC, mid isc */
>> 	struct list_head gc_low_list;	/* Full lines ready to GC, low isc */
>> 
>> +	struct list_head gc_werr_list;  /* Write err recovery list */
>> +
>> 	struct list_head gc_full_list;	/* Full lines ready to GC, no valid */
>> 	struct list_head gc_empty_list;	/* Full lines close, all valid */
>> 
>> @@ -891,6 +905,9 @@ void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line,
>> 			    bool used);
>> int pblk_rl_is_limit(struct pblk_rl *rl);
>> 
>> +void pblk_rl_werr_line_in(struct pblk_rl *rl);
>> +void pblk_rl_werr_line_out(struct pblk_rl *rl);
>> +
>> /*
>> * pblk sysfs
>> */
>> --
>> 2.7.4
> 
> LGTM
> 
> Reviewed-by: Javier González <javier@cnexlabs.com>

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Re: [PATCH v2 3/3] lightnvm: pblk: fix smeta write error path

[Javier Gonzalez]

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> On 24 Apr 2018, at 07.45, Hans Holmberg <hans.ml.holmberg@owltronix.com> wrote:
> 
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> Smeta write errors were previously ignored. Skip these
> lines instead and throw them back on the free
> list, so the chunks will go through a reset cycle
> before we attempt to use the line again.
> 
> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
> ---
> drivers/lightnvm/pblk-core.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index 413cf3b..dec1bb4 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -849,9 +849,10 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
> 	atomic_dec(&pblk->inflight_io);
> 
> 	if (rqd.error) {
> -		if (dir == PBLK_WRITE)
> +		if (dir == PBLK_WRITE) {
> 			pblk_log_write_err(pblk, &rqd);
> -		else if (dir == PBLK_READ)
> +			ret = 1;
> +		} else if (dir == PBLK_READ)
> 			pblk_log_read_err(pblk, &rqd);
> 	}
> 
> @@ -1120,7 +1121,7 @@ static int pblk_line_init_bb(struct pblk *pblk, struct pblk_line *line,
> 
> 	if (init && pblk_line_submit_smeta_io(pblk, line, off, PBLK_WRITE)) {
> 		pr_debug("pblk: line smeta I/O failed. Retry\n");
> -		return 1;
> +		return 0;
> 	}
> 
> 	bitmap_copy(line->invalid_bitmap, line->map_bitmap, lm->sec_per_line);
> --
> 2.7.4

LGTM

Reviewed-by: Javier González <javier@cnexlabs.com>


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Re: [PATCH v2 0/3] Rework write error handling in pblk

[Matias Bjørling]

On 04/24/2018 07:45 AM, Hans Holmberg wrote:
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> This patch series fixes the(currently incomplete) write error handling
> in pblk by:
> 
>   * queuing and re-submitting failed writes in the write buffer
>   * evacuating valid data data in lines with write failures, so the
>     chunk(s) with write failures can be reset to a known state by the fw
> 
> Lines with failures in smeta are put back on the free list.
> Failed chunks will be reset on the next use.
> 
> If a write failes in emeta, the lba list is cached so the line can be
> garbage collected without scanning the out-of-band area.
> 
> Changes in V2:
> - Added the recov_writes counter increase to the new path
> - Moved lba list emeta reading during gc to a separate function
> - Allocating the saved lba list with pblk_malloc instead of kmalloc
> - Fixed formatting issues
> - Removed dead code
> 
> Hans Holmberg (3):
>    lightnvm: pblk: rework write error recovery path
>    lightnvm: pblk: garbage collect lines with failed writes
>    lightnvm: pblk: fix smeta write error path
> 
>   drivers/lightnvm/pblk-core.c     |  52 +++++++-
>   drivers/lightnvm/pblk-gc.c       | 102 +++++++++------
>   drivers/lightnvm/pblk-init.c     |  47 ++++---
>   drivers/lightnvm/pblk-rb.c       |  39 ------
>   drivers/lightnvm/pblk-recovery.c |  91 -------------
>   drivers/lightnvm/pblk-rl.c       |  29 ++++-
>   drivers/lightnvm/pblk-sysfs.c    |  15 ++-
>   drivers/lightnvm/pblk-write.c    | 269 ++++++++++++++++++++++++++-------------
>   drivers/lightnvm/pblk.h          |  36 ++++--
>   9 files changed, 384 insertions(+), 296 deletions(-)
> 

Applied for 4.18.