lightnvm: physical block device (pblk) target

This patch introduces pblk, a host-side translation layer for
Open-Channel SSDs to expose them like block devices. The translation
layer allows data placement decisions, and I/O scheduling to be
managed by the host, enabling users to optimize the SSD for their
specific workloads.

An open-channel SSD has a set of LUNs (parallel units) and a
collection of blocks. Each block can be read in any order, but
writes must be sequential. Writes may also fail, and if a block
requires it, must also be reset before new writes can be
applied.

To manage the constraints, pblk maintains a logical to
physical address (L2P) table,  write cache, garbage
collection logic, recovery scheme, and logic to rate-limit
user I/Os versus garbage collection I/Os.

The L2P table is fully-associative and manages sectors at a
4KB granularity. Pblk stores the L2P table in two places, in
the out-of-band area of the media and on the last page of a
line. In the cause of a power failure, pblk will perform a
scan to recover the L2P table.

The user data is organized into lines. A line is data
striped across blocks and LUNs. The lines enable the host to
reduce the amount of metadata to maintain besides the user
data and makes it easier to implement RAID or erasure coding
in the future.

pblk implements multi-tenant support and can be instantiated
multiple times on the same drive. Each instance owns a
portion of the SSD - both regarding I/O bandwidth and
capacity - providing I/O isolation for each case.

Finally, pblk also exposes a sysfs interface that allows
user-space to peek into the internals of pblk. The interface
is available at /dev/block/*/pblk/ where * is the block
device name exposed.

This work also contains contributions from:
  Matias Bjørling <matias@cnexlabs.com>
  Simon A. F. Lund <slund@cnexlabs.com>
  Young Tack Jin <youngtack.jin@gmail.com>
  Huaicheng Li <huaicheng@cs.uchicago.edu>

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 1655 insertions, 0 deletions

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
new file mode 100644
index 000000000000..a2bcd098babc
--- /dev/null
+++ b/drivers/lightnvm/pblk-core.c
@@ -0,0 +1,1655 @@
+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-core.c - pblk's core functionality
+ *
+ */
+
+#include "pblk.h"
+#include <linux/time.h>
+
+static void pblk_mark_bb(struct pblk *pblk, struct pblk_line *line,
+			 struct ppa_addr *ppa)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	int pos = pblk_dev_ppa_to_pos(geo, *ppa);
+
+	pr_debug("pblk: erase failed: line:%d, pos:%d\n", line->id, pos);
+	atomic_long_inc(&pblk->erase_failed);
+
+	if (test_and_set_bit(pos, line->blk_bitmap))
+		pr_err("pblk: attempted to erase bb: line:%d, pos:%d\n",
+							line->id, pos);
+
+	pblk_line_run_ws(pblk, NULL, ppa, pblk_line_mark_bb);
+}
+
+static void __pblk_end_io_erase(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	struct pblk_line *line;
+
+	line = &pblk->lines[pblk_dev_ppa_to_line(rqd->ppa_addr)];
+	atomic_dec(&line->left_seblks);
+
+	if (rqd->error) {
+		struct ppa_addr *ppa;
+
+		ppa = kmalloc(sizeof(struct ppa_addr), GFP_ATOMIC);
+		if (!ppa)
+			return;
+
+		*ppa = rqd->ppa_addr;
+		pblk_mark_bb(pblk, line, ppa);
+	}
+}
+
+/* Erase completion assumes that only one block is erased at the time */
+static void pblk_end_io_erase(struct nvm_rq *rqd)
+{
+	struct pblk *pblk = rqd->private;
+
+	up(&pblk->erase_sem);
+	__pblk_end_io_erase(pblk, rqd);
+	mempool_free(rqd, pblk->r_rq_pool);
+}
+
+static void __pblk_map_invalidate(struct pblk *pblk, struct pblk_line *line,
+				  u64 paddr)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list = NULL;
+
+	/* Lines being reclaimed (GC'ed) cannot be invalidated. Before the L2P
+	 * table is modified with reclaimed sectors, a check is done to endure
+	 * that newer updates are not overwritten.
+	 */
+	spin_lock(&line->lock);
+	if (line->state == PBLK_LINESTATE_GC ||
+					line->state == PBLK_LINESTATE_FREE) {
+		spin_unlock(&line->lock);
+		return;
+	}
+
+	if (test_and_set_bit(paddr, line->invalid_bitmap)) {
+		WARN_ONCE(1, "pblk: double invalidate\n");
+		spin_unlock(&line->lock);
+		return;
+	}
+	line->vsc--;
+
+	if (line->state == PBLK_LINESTATE_CLOSED)
+		move_list = pblk_line_gc_list(pblk, line);
+	spin_unlock(&line->lock);
+
+	if (move_list) {
+		spin_lock(&l_mg->gc_lock);
+		spin_lock(&line->lock);
+		/* Prevent moving a line that has just been chosen for GC */
+		if (line->state == PBLK_LINESTATE_GC ||
+					line->state == PBLK_LINESTATE_FREE) {
+			spin_unlock(&line->lock);
+			spin_unlock(&l_mg->gc_lock);
+			return;
+		}
+		spin_unlock(&line->lock);
+
+		list_move_tail(&line->list, move_list);
+		spin_unlock(&l_mg->gc_lock);
+	}
+}
+
+void pblk_map_invalidate(struct pblk *pblk, struct ppa_addr ppa)
+{
+	struct pblk_line *line;
+	u64 paddr;
+	int line_id;
+
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a device address */
+	BUG_ON(pblk_addr_in_cache(ppa));
+	BUG_ON(pblk_ppa_empty(ppa));
+#endif
+
+	line_id = pblk_tgt_ppa_to_line(ppa);
+	line = &pblk->lines[line_id];
+	paddr = pblk_dev_ppa_to_line_addr(pblk, ppa);
+
+	__pblk_map_invalidate(pblk, line, paddr);
+}
+
+void pblk_map_pad_invalidate(struct pblk *pblk, struct pblk_line *line,
+			     u64 paddr)
+{
+	__pblk_map_invalidate(pblk, line, paddr);
+
+	pblk_rb_sync_init(&pblk->rwb, NULL);
+	line->left_ssecs--;
+	if (!line->left_ssecs)
+		pblk_line_run_ws(pblk, line, NULL, pblk_line_close_ws);
+	pblk_rb_sync_end(&pblk->rwb, NULL);
+}
+
+static void pblk_invalidate_range(struct pblk *pblk, sector_t slba,
+				  unsigned int nr_secs)
+{
+	sector_t lba;
+
+	spin_lock(&pblk->trans_lock);
+	for (lba = slba; lba < slba + nr_secs; lba++) {
+		struct ppa_addr ppa;
+
+		ppa = pblk_trans_map_get(pblk, lba);
+
+		if (!pblk_addr_in_cache(ppa) && !pblk_ppa_empty(ppa))
+			pblk_map_invalidate(pblk, ppa);
+
+		pblk_ppa_set_empty(&ppa);
+		pblk_trans_map_set(pblk, lba, ppa);
+	}
+	spin_unlock(&pblk->trans_lock);
+}
+
+struct nvm_rq *pblk_alloc_rqd(struct pblk *pblk, int rw)
+{
+	mempool_t *pool;
+	struct nvm_rq *rqd;
+	int rq_size;
+
+	if (rw == WRITE) {
+		pool = pblk->w_rq_pool;
+		rq_size = pblk_w_rq_size;
+	} else {
+		pool = pblk->r_rq_pool;
+		rq_size = pblk_r_rq_size;
+	}
+
+	rqd = mempool_alloc(pool, GFP_KERNEL);
+	memset(rqd, 0, rq_size);
+
+	return rqd;
+}
+
+void pblk_free_rqd(struct pblk *pblk, struct nvm_rq *rqd, int rw)
+{
+	mempool_t *pool;
+
+	if (rw == WRITE)
+		pool = pblk->w_rq_pool;
+	else
+		pool = pblk->r_rq_pool;
+
+	mempool_free(rqd, pool);
+}
+
+void pblk_bio_free_pages(struct pblk *pblk, struct bio *bio, int off,
+			 int nr_pages)
+{
+	struct bio_vec bv;
+	int i;
+
+	WARN_ON(off + nr_pages != bio->bi_vcnt);
+
+	bio_advance(bio, off * PBLK_EXPOSED_PAGE_SIZE);
+	for (i = off; i < nr_pages + off; i++) {
+		bv = bio->bi_io_vec[i];
+		mempool_free(bv.bv_page, pblk->page_pool);
+	}
+}
+
+int pblk_bio_add_pages(struct pblk *pblk, struct bio *bio, gfp_t flags,
+		       int nr_pages)
+{
+	struct request_queue *q = pblk->dev->q;
+	struct page *page;
+	int i, ret;
+
+	for (i = 0; i < nr_pages; i++) {
+		page = mempool_alloc(pblk->page_pool, flags);
+		if (!page)
+			goto err;
+
+		ret = bio_add_pc_page(q, bio, page, PBLK_EXPOSED_PAGE_SIZE, 0);
+		if (ret != PBLK_EXPOSED_PAGE_SIZE) {
+			pr_err("pblk: could not add page to bio\n");
+			mempool_free(page, pblk->page_pool);
+			goto err;
+		}
+	}
+
+	return 0;
+err:
+	pblk_bio_free_pages(pblk, bio, 0, i - 1);
+	return -1;
+}
+
+static void pblk_write_kick(struct pblk *pblk)
+{
+	wake_up_process(pblk->writer_ts);
+	mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(1000));
+}
+
+void pblk_write_timer_fn(unsigned long data)
+{
+	struct pblk *pblk = (struct pblk *)data;
+
+	/* kick the write thread every tick to flush outstanding data */
+	pblk_write_kick(pblk);
+}
+
+void pblk_write_should_kick(struct pblk *pblk)
+{
+	unsigned int secs_avail = pblk_rb_read_count(&pblk->rwb);
+
+	if (secs_avail >= pblk->min_write_pgs)
+		pblk_write_kick(pblk);
+}
+
+void pblk_end_bio_sync(struct bio *bio)
+{
+	struct completion *waiting = bio->bi_private;
+
+	complete(waiting);
+}
+
+void pblk_end_io_sync(struct nvm_rq *rqd)
+{
+	struct completion *waiting = rqd->private;
+
+	complete(waiting);
+}
+
+void pblk_flush_writer(struct pblk *pblk)
+{
+	struct bio *bio;
+	int ret;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	bio = bio_alloc(GFP_KERNEL, 1);
+	if (!bio)
+		return;
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_OP_FLUSH);
+	bio->bi_private = &wait;
+	bio->bi_end_io = pblk_end_bio_sync;
+
+	ret = pblk_write_to_cache(pblk, bio, 0);
+	if (ret == NVM_IO_OK) {
+		if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+			pr_err("pblk: flush cache timed out\n");
+		}
+	} else if (ret != NVM_IO_DONE) {
+		pr_err("pblk: tear down bio failed\n");
+	}
+
+	if (bio->bi_error)
+		pr_err("pblk: flush sync write failed (%u)\n", bio->bi_error);
+
+	bio_put(bio);
+}
+
+struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list = NULL;
+
+	if (!line->vsc) {
+		if (line->gc_group != PBLK_LINEGC_FULL) {
+			line->gc_group = PBLK_LINEGC_FULL;
+			move_list = &l_mg->gc_full_list;
+		}
+	} else if (line->vsc < lm->mid_thrs) {
+		if (line->gc_group != PBLK_LINEGC_HIGH) {
+			line->gc_group = PBLK_LINEGC_HIGH;
+			move_list = &l_mg->gc_high_list;
+		}
+	} else if (line->vsc < lm->high_thrs) {
+		if (line->gc_group != PBLK_LINEGC_MID) {
+			line->gc_group = PBLK_LINEGC_MID;
+			move_list = &l_mg->gc_mid_list;
+		}
+	} else if (line->vsc < line->sec_in_line) {
+		if (line->gc_group != PBLK_LINEGC_LOW) {
+			line->gc_group = PBLK_LINEGC_LOW;
+			move_list = &l_mg->gc_low_list;
+		}
+	} else if (line->vsc == line->sec_in_line) {
+		if (line->gc_group != PBLK_LINEGC_EMPTY) {
+			line->gc_group = PBLK_LINEGC_EMPTY;
+			move_list = &l_mg->gc_empty_list;
+		}
+	} else {
+		line->state = PBLK_LINESTATE_CORRUPT;
+		line->gc_group = PBLK_LINEGC_NONE;
+		move_list =  &l_mg->corrupt_list;
+		pr_err("pblk: corrupted vsc for line %d, vsc:%d (%d/%d/%d)\n",
+						line->id, line->vsc,
+						line->sec_in_line,
+						lm->high_thrs, lm->mid_thrs);
+	}
+
+	return move_list;
+}
+
+void pblk_discard(struct pblk *pblk, struct bio *bio)
+{
+	sector_t slba = pblk_get_lba(bio);
+	sector_t nr_secs = pblk_get_secs(bio);
+
+	pblk_invalidate_range(pblk, slba, nr_secs);
+}
+
+struct ppa_addr pblk_get_lba_map(struct pblk *pblk, sector_t lba)
+{
+	struct ppa_addr ppa;
+
+	spin_lock(&pblk->trans_lock);
+	ppa = pblk_trans_map_get(pblk, lba);
+	spin_unlock(&pblk->trans_lock);
+
+	return ppa;
+}
+
+void pblk_log_write_err(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	atomic_long_inc(&pblk->write_failed);
+#ifdef CONFIG_NVM_DEBUG
+	pblk_print_failed_rqd(pblk, rqd, rqd->error);
+#endif
+}
+
+void pblk_log_read_err(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	/* Empty page read is not necessarily an error (e.g., L2P recovery) */
+	if (rqd->error == NVM_RSP_ERR_EMPTYPAGE) {
+		atomic_long_inc(&pblk->read_empty);
+		return;
+	}
+
+	switch (rqd->error) {
+	case NVM_RSP_WARN_HIGHECC:
+		atomic_long_inc(&pblk->read_high_ecc);
+		break;
+	case NVM_RSP_ERR_FAILECC:
+	case NVM_RSP_ERR_FAILCRC:
+		atomic_long_inc(&pblk->read_failed);
+		break;
+	default:
+		pr_err("pblk: unknown read error:%d\n", rqd->error);
+	}
+#ifdef CONFIG_NVM_DEBUG
+	pblk_print_failed_rqd(pblk, rqd, rqd->error);
+#endif
+}
+
+int pblk_submit_io(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+
+#ifdef CONFIG_NVM_DEBUG
+	struct ppa_addr *ppa_list;
+
+	ppa_list = (rqd->nr_ppas > 1) ? rqd->ppa_list : &rqd->ppa_addr;
+	if (pblk_boundary_ppa_checks(dev, ppa_list, rqd->nr_ppas)) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	if (rqd->opcode == NVM_OP_PWRITE) {
+		struct pblk_line *line;
+		struct ppa_addr ppa;
+		int i;
+
+		for (i = 0; i < rqd->nr_ppas; i++) {
+			ppa = ppa_list[i];
+			line = &pblk->lines[pblk_dev_ppa_to_line(ppa)];
+
+			spin_lock(&line->lock);
+			if (line->state != PBLK_LINESTATE_OPEN) {
+				pr_err("pblk: bad ppa: line:%d,state:%d\n",
+							line->id, line->state);
+				WARN_ON(1);
+				spin_unlock(&line->lock);
+				return -EINVAL;
+			}
+			spin_unlock(&line->lock);
+		}
+	}
+#endif
+	return nvm_submit_io(dev, rqd);
+}
+
+struct bio *pblk_bio_map_addr(struct pblk *pblk, void *data,
+			      unsigned int nr_secs, unsigned int len,
+			      gfp_t gfp_mask)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	void *kaddr = data;
+	struct page *page;
+	struct bio *bio;
+	int i, ret;
+
+	if (l_mg->emeta_alloc_type == PBLK_KMALLOC_META)
+		return bio_map_kern(dev->q, kaddr, len, gfp_mask);
+
+	bio = bio_kmalloc(gfp_mask, nr_secs);
+	if (!bio)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < nr_secs; i++) {
+		page = vmalloc_to_page(kaddr);
+		if (!page) {
+			pr_err("pblk: could not map vmalloc bio\n");
+			bio_put(bio);
+			bio = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+
+		ret = bio_add_pc_page(dev->q, bio, page, PAGE_SIZE, 0);
+		if (ret != PAGE_SIZE) {
+			pr_err("pblk: could not add page to bio\n");
+			bio_put(bio);
+			bio = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+
+		kaddr += PAGE_SIZE;
+	}
+out:
+	return bio;
+}
+
+int pblk_calc_secs(struct pblk *pblk, unsigned long secs_avail,
+		   unsigned long secs_to_flush)
+{
+	int max = pblk->max_write_pgs;
+	int min = pblk->min_write_pgs;
+	int secs_to_sync = 0;
+
+	if (secs_avail >= max)
+		secs_to_sync = max;
+	else if (secs_avail >= min)
+		secs_to_sync = min * (secs_avail / min);
+	else if (secs_to_flush)
+		secs_to_sync = min;
+
+	return secs_to_sync;
+}
+
+static u64 __pblk_alloc_page(struct pblk *pblk, struct pblk_line *line,
+			     int nr_secs)
+{
+	u64 addr;
+	int i;
+
+	/* logic error: ppa out-of-bounds. Prevent generating bad address */
+	if (line->cur_sec + nr_secs > pblk->lm.sec_per_line) {
+		WARN(1, "pblk: page allocation out of bounds\n");
+		nr_secs = pblk->lm.sec_per_line - line->cur_sec;
+	}
+
+	line->cur_sec = addr = find_next_zero_bit(line->map_bitmap,
+					pblk->lm.sec_per_line, line->cur_sec);
+	for (i = 0; i < nr_secs; i++, line->cur_sec++)
+		WARN_ON(test_and_set_bit(line->cur_sec, line->map_bitmap));
+
+	return addr;
+}
+
+u64 pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
+{
+	u64 addr;
+
+	/* Lock needed in case a write fails and a recovery needs to remap
+	 * failed write buffer entries
+	 */
+	spin_lock(&line->lock);
+	addr = __pblk_alloc_page(pblk, line, nr_secs);
+	line->left_msecs -= nr_secs;
+	WARN(line->left_msecs < 0, "pblk: page allocation out of bounds\n");
+	spin_unlock(&line->lock);
+
+	return addr;
+}
+
+/*
+ * Submit emeta to one LUN in the raid line at the time to avoid a deadlock when
+ * taking the per LUN semaphore.
+ */
+static int pblk_line_submit_emeta_io(struct pblk *pblk, struct pblk_line *line,
+				     u64 paddr, int dir)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct bio *bio;
+	struct nvm_rq rqd;
+	struct ppa_addr *ppa_list;
+	dma_addr_t dma_ppa_list;
+	void *emeta = line->emeta;
+	int min = pblk->min_write_pgs;
+	int left_ppas = lm->emeta_sec;
+	int id = line->id;
+	int rq_ppas, rq_len;
+	int cmd_op, bio_op;
+	int flags;
+	int i, j;
+	int ret;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	if (dir == WRITE) {
+		bio_op = REQ_OP_WRITE;
+		cmd_op = NVM_OP_PWRITE;
+		flags = pblk_set_progr_mode(pblk, WRITE);
+	} else if (dir == READ) {
+		bio_op = REQ_OP_READ;
+		cmd_op = NVM_OP_PREAD;
+		flags = pblk_set_read_mode(pblk);
+	} else
+		return -EINVAL;
+
+	ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL, &dma_ppa_list);
+	if (!ppa_list)
+		return -ENOMEM;
+
+next_rq:
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	rq_ppas = pblk_calc_secs(pblk, left_ppas, 0);
+	rq_len = rq_ppas * geo->sec_size;
+
+	bio = pblk_bio_map_addr(pblk, emeta, rq_ppas, rq_len, GFP_KERNEL);
+	if (IS_ERR(bio)) {
+		ret = PTR_ERR(bio);
+		goto free_rqd_dma;
+	}
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, bio_op, 0);
+
+	rqd.bio = bio;
+	rqd.opcode = cmd_op;
+	rqd.flags = flags;
+	rqd.nr_ppas = rq_ppas;
+	rqd.ppa_list = ppa_list;
+	rqd.dma_ppa_list = dma_ppa_list;
+	rqd.end_io = pblk_end_io_sync;
+	rqd.private = &wait;
+
+	if (dir == WRITE) {
+		for (i = 0; i < rqd.nr_ppas; ) {
+			spin_lock(&line->lock);
+			paddr = __pblk_alloc_page(pblk, line, min);
+			spin_unlock(&line->lock);
+			for (j = 0; j < min; j++, i++, paddr++)
+				rqd.ppa_list[i] =
+					addr_to_gen_ppa(pblk, paddr, id);
+		}
+	} else {
+		for (i = 0; i < rqd.nr_ppas; ) {
+			struct ppa_addr ppa = addr_to_gen_ppa(pblk, paddr, id);
+			int pos = pblk_dev_ppa_to_pos(geo, ppa);
+
+			while (test_bit(pos, line->blk_bitmap)) {
+				paddr += min;
+				if (pblk_boundary_paddr_checks(pblk, paddr)) {
+					pr_err("pblk: corrupt emeta line:%d\n",
+								line->id);
+					bio_put(bio);
+					ret = -EINTR;
+					goto free_rqd_dma;
+				}
+
+				ppa = addr_to_gen_ppa(pblk, paddr, id);
+				pos = pblk_dev_ppa_to_pos(geo, ppa);
+			}
+
+			if (pblk_boundary_paddr_checks(pblk, paddr + min)) {
+				pr_err("pblk: corrupt emeta line:%d\n",
+								line->id);
+				bio_put(bio);
+				ret = -EINTR;
+				goto free_rqd_dma;
+			}
+
+			for (j = 0; j < min; j++, i++, paddr++)
+				rqd.ppa_list[i] =
+					addr_to_gen_ppa(pblk, paddr, line->id);
+		}
+	}
+
+	ret = pblk_submit_io(pblk, &rqd);
+	if (ret) {
+		pr_err("pblk: emeta I/O submission failed: %d\n", ret);
+		bio_put(bio);
+		goto free_rqd_dma;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: emeta I/O timed out\n");
+	}
+	reinit_completion(&wait);
+
+	bio_put(bio);
+
+	if (rqd.error) {
+		if (dir == WRITE)
+			pblk_log_write_err(pblk, &rqd);
+		else
+			pblk_log_read_err(pblk, &rqd);
+	}
+
+	emeta += rq_len;
+	left_ppas -= rq_ppas;
+	if (left_ppas)
+		goto next_rq;
+free_rqd_dma:
+	nvm_dev_dma_free(dev->parent, ppa_list, dma_ppa_list);
+	return ret;
+}
+
+u64 pblk_line_smeta_start(struct pblk *pblk, struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	int bit;
+
+	/* This usually only happens on bad lines */
+	bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
+	if (bit >= lm->blk_per_line)
+		return -1;
+
+	return bit * geo->sec_per_pl;
+}
+
+static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
+				     u64 paddr, int dir)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct bio *bio;
+	struct nvm_rq rqd;
+	__le64 *lba_list = NULL;
+	int i, ret;
+	int cmd_op, bio_op;
+	int flags;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	if (dir == WRITE) {
+		bio_op = REQ_OP_WRITE;
+		cmd_op = NVM_OP_PWRITE;
+		flags = pblk_set_progr_mode(pblk, WRITE);
+		lba_list = pblk_line_emeta_to_lbas(line->emeta);
+	} else if (dir == READ) {
+		bio_op = REQ_OP_READ;
+		cmd_op = NVM_OP_PREAD;
+		flags = pblk_set_read_mode(pblk);
+	} else
+		return -EINVAL;
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	rqd.ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+							&rqd.dma_ppa_list);
+	if (!rqd.ppa_list)
+		return -ENOMEM;
+
+	bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL);
+	if (IS_ERR(bio)) {
+		ret = PTR_ERR(bio);
+		goto free_ppa_list;
+	}
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, bio_op, 0);
+
+	rqd.bio = bio;
+	rqd.opcode = cmd_op;
+	rqd.flags = flags;
+	rqd.nr_ppas = lm->smeta_sec;
+	rqd.end_io = pblk_end_io_sync;
+	rqd.private = &wait;
+
+	for (i = 0; i < lm->smeta_sec; i++, paddr++) {
+		rqd.ppa_list[i] = addr_to_gen_ppa(pblk, paddr, line->id);
+		if (dir == WRITE)
+			lba_list[paddr] = cpu_to_le64(ADDR_EMPTY);
+	}
+
+	/*
+	 * This I/O is sent by the write thread when a line is replace. Since
+	 * the write thread is the only one sending write and erase commands,
+	 * there is no need to take the LUN semaphore.
+	 */
+	ret = pblk_submit_io(pblk, &rqd);
+	if (ret) {
+		pr_err("pblk: smeta I/O submission failed: %d\n", ret);
+		bio_put(bio);
+		goto free_ppa_list;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: smeta I/O timed out\n");
+	}
+
+	if (rqd.error) {
+		if (dir == WRITE)
+			pblk_log_write_err(pblk, &rqd);
+		else
+			pblk_log_read_err(pblk, &rqd);
+	}
+
+free_ppa_list:
+	nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
+
+	return ret;
+}
+
+int pblk_line_read_smeta(struct pblk *pblk, struct pblk_line *line)
+{
+	u64 bpaddr = pblk_line_smeta_start(pblk, line);
+
+	return pblk_line_submit_smeta_io(pblk, line, bpaddr, READ);
+}
+
+int pblk_line_read_emeta(struct pblk *pblk, struct pblk_line *line)
+{
+	return pblk_line_submit_emeta_io(pblk, line, line->emeta_ssec, READ);
+}
+
+static void pblk_setup_e_rq(struct pblk *pblk, struct nvm_rq *rqd,
+			    struct ppa_addr ppa)
+{
+	rqd->opcode = NVM_OP_ERASE;
+	rqd->ppa_addr = ppa;
+	rqd->nr_ppas = 1;
+	rqd->flags = pblk_set_progr_mode(pblk, ERASE);
+	rqd->bio = NULL;
+}
+
+static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
+{
+	struct nvm_rq rqd;
+	int ret;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	pblk_setup_e_rq(pblk, &rqd, ppa);
+
+	rqd.end_io = pblk_end_io_sync;
+	rqd.private = &wait;
+
+	/* The write thread schedules erases so that it minimizes disturbances
+	 * with writes. Thus, there is no need to take the LUN semaphore.
+	 */
+	ret = pblk_submit_io(pblk, &rqd);
+	if (ret) {
+		struct nvm_tgt_dev *dev = pblk->dev;
+		struct nvm_geo *geo = &dev->geo;
+
+		pr_err("pblk: could not sync erase line:%d,blk:%d\n",
+					pblk_dev_ppa_to_line(ppa),
+					pblk_dev_ppa_to_pos(geo, ppa));
+
+		rqd.error = ret;
+		goto out;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: sync erase timed out\n");
+	}
+
+out:
+	rqd.private = pblk;
+	__pblk_end_io_erase(pblk, &rqd);
+
+	return 0;
+}
+
+int pblk_line_erase(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct ppa_addr ppa;
+	int bit = -1;
+
+	/* Erase one block at the time and only erase good blocks */
+	while ((bit = find_next_zero_bit(line->erase_bitmap, lm->blk_per_line,
+						bit + 1)) < lm->blk_per_line) {
+		ppa = pblk->luns[bit].bppa; /* set ch and lun */
+		ppa.g.blk = line->id;
+
+		/* If the erase fails, the block is bad and should be marked */
+		line->left_eblks--;
+		WARN_ON(test_and_set_bit(bit, line->erase_bitmap));
+
+		if (pblk_blk_erase_sync(pblk, ppa)) {
+			pr_err("pblk: failed to erase line %d\n", line->id);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+/* For now lines are always assumed full lines. Thus, smeta former and current
+ * lun bitmaps are omitted.
+ */
+static int pblk_line_set_metadata(struct pblk *pblk, struct pblk_line *line,
+				  struct pblk_line *cur)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct line_smeta *smeta = line->smeta;
+	struct line_emeta *emeta = line->emeta;
+	int nr_blk_line;
+
+	/* After erasing the line, new bad blocks might appear and we risk
+	 * having an invalid line
+	 */
+	nr_blk_line = lm->blk_per_line -
+			bitmap_weight(line->blk_bitmap, lm->blk_per_line);
+	if (nr_blk_line < lm->min_blk_line) {
+		spin_lock(&l_mg->free_lock);
+		spin_lock(&line->lock);
+		line->state = PBLK_LINESTATE_BAD;
+		spin_unlock(&line->lock);
+
+		list_add_tail(&line->list, &l_mg->bad_list);
+		spin_unlock(&l_mg->free_lock);
+
+		pr_debug("pblk: line %d is bad\n", line->id);
+
+		return 0;
+	}
+
+	/* Run-time metadata */
+	line->lun_bitmap = ((void *)(smeta)) + sizeof(struct line_smeta);
+
+	/* Mark LUNs allocated in this line (all for now) */
+	bitmap_set(line->lun_bitmap, 0, lm->lun_bitmap_len);
+
+	smeta->header.identifier = cpu_to_le32(PBLK_MAGIC);
+	memcpy(smeta->header.uuid, pblk->instance_uuid, 16);
+	smeta->header.id = cpu_to_le32(line->id);
+	smeta->header.type = cpu_to_le16(line->type);
+	smeta->header.version = cpu_to_le16(1);
+
+	/* Start metadata */
+	smeta->seq_nr = cpu_to_le64(line->seq_nr);
+	smeta->window_wr_lun = cpu_to_le32(geo->nr_luns);
+
+	/* Fill metadata among lines */
+	if (cur) {
+		memcpy(line->lun_bitmap, cur->lun_bitmap, lm->lun_bitmap_len);
+		smeta->prev_id = cpu_to_le32(cur->id);
+		cur->emeta->next_id = cpu_to_le32(line->id);
+	} else {
+		smeta->prev_id = cpu_to_le32(PBLK_LINE_EMPTY);
+	}
+
+	/* All smeta must be set at this point */
+	smeta->header.crc = cpu_to_le32(pblk_calc_meta_header_crc(pblk, smeta));
+	smeta->crc = cpu_to_le32(pblk_calc_smeta_crc(pblk, smeta));
+
+	/* End metadata */
+	memcpy(&emeta->header, &smeta->header, sizeof(struct line_header));
+	emeta->seq_nr = cpu_to_le64(line->seq_nr);
+	emeta->nr_lbas = cpu_to_le64(line->sec_in_line);
+	emeta->nr_valid_lbas = cpu_to_le64(0);
+	emeta->next_id = cpu_to_le32(PBLK_LINE_EMPTY);
+	emeta->crc = cpu_to_le32(0);
+	emeta->prev_id = smeta->prev_id;
+
+	return 1;
+}
+
+/* For now lines are always assumed full lines. Thus, smeta former and current
+ * lun bitmaps are omitted.
+ */
+static int pblk_line_init_bb(struct pblk *pblk, struct pblk_line *line,
+			     int init)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	int nr_bb = 0;
+	u64 off;
+	int bit = -1;
+
+	line->sec_in_line = lm->sec_per_line;
+
+	/* Capture bad block information on line mapping bitmaps */
+	while ((bit = find_next_bit(line->blk_bitmap, lm->blk_per_line,
+					bit + 1)) < lm->blk_per_line) {
+		off = bit * geo->sec_per_pl;
+		bitmap_shift_left(l_mg->bb_aux, l_mg->bb_template, off,
+							lm->sec_per_line);
+		bitmap_or(line->map_bitmap, line->map_bitmap, l_mg->bb_aux,
+							lm->sec_per_line);
+		line->sec_in_line -= geo->sec_per_blk;
+		if (bit >= lm->emeta_bb)
+			nr_bb++;
+	}
+
+	/* Mark smeta metadata sectors as bad sectors */
+	bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
+	off = bit * geo->sec_per_pl;
+retry_smeta:
+	bitmap_set(line->map_bitmap, off, lm->smeta_sec);
+	line->sec_in_line -= lm->smeta_sec;
+	line->smeta_ssec = off;
+	line->cur_sec = off + lm->smeta_sec;
+
+	if (init && pblk_line_submit_smeta_io(pblk, line, off, WRITE)) {
+		pr_debug("pblk: line smeta I/O failed. Retry\n");
+		off += geo->sec_per_pl;
+		goto retry_smeta;
+	}
+
+	bitmap_copy(line->invalid_bitmap, line->map_bitmap, lm->sec_per_line);
+
+	/* Mark emeta metadata sectors as bad sectors. We need to consider bad
+	 * blocks to make sure that there are enough sectors to store emeta
+	 */
+	bit = lm->sec_per_line;
+	off = lm->sec_per_line - lm->emeta_sec;
+	bitmap_set(line->invalid_bitmap, off, lm->emeta_sec);
+	while (nr_bb) {
+		off -= geo->sec_per_pl;
+		if (!test_bit(off, line->invalid_bitmap)) {
+			bitmap_set(line->invalid_bitmap, off, geo->sec_per_pl);
+			nr_bb--;
+		}
+	}
+
+	line->sec_in_line -= lm->emeta_sec;
+	line->emeta_ssec = off;
+	line->vsc = line->left_ssecs = line->left_msecs = line->sec_in_line;
+
+	if (lm->sec_per_line - line->sec_in_line !=
+		bitmap_weight(line->invalid_bitmap, lm->sec_per_line)) {
+		spin_lock(&line->lock);
+		line->state = PBLK_LINESTATE_BAD;
+		spin_unlock(&line->lock);
+
+		list_add_tail(&line->list, &l_mg->bad_list);
+		pr_err("pblk: unexpected line %d is bad\n", line->id);
+
+		return 0;
+	}
+
+	return 1;
+}
+
+static int pblk_line_prepare(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+
+	line->map_bitmap = mempool_alloc(pblk->line_meta_pool, GFP_ATOMIC);
+	if (!line->map_bitmap)
+		return -ENOMEM;
+	memset(line->map_bitmap, 0, lm->sec_bitmap_len);
+
+	/* invalid_bitmap is special since it is used when line is closed. No
+	 * need to zeroized; it will be initialized using bb info form
+	 * map_bitmap
+	 */
+	line->invalid_bitmap = mempool_alloc(pblk->line_meta_pool, GFP_ATOMIC);
+	if (!line->invalid_bitmap) {
+		mempool_free(line->map_bitmap, pblk->line_meta_pool);
+		return -ENOMEM;
+	}
+
+	spin_lock(&line->lock);
+	if (line->state != PBLK_LINESTATE_FREE) {
+		spin_unlock(&line->lock);
+		WARN(1, "pblk: corrupted line state\n");
+		return -EINTR;
+	}
+	line->state = PBLK_LINESTATE_OPEN;
+	spin_unlock(&line->lock);
+
+	/* Bad blocks do not need to be erased */
+	bitmap_copy(line->erase_bitmap, line->blk_bitmap, lm->blk_per_line);
+	line->left_eblks = line->blk_in_line;
+	atomic_set(&line->left_seblks, line->left_eblks);
+
+	kref_init(&line->ref);
+
+	return 0;
+}
+
+int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	int ret;
+
+	spin_lock(&l_mg->free_lock);
+	l_mg->data_line = line;
+	list_del(&line->list);
+	spin_unlock(&l_mg->free_lock);
+
+	ret = pblk_line_prepare(pblk, line);
+	if (ret) {
+		list_add(&line->list, &l_mg->free_list);
+		return ret;
+	}
+
+	pblk_rl_free_lines_dec(&pblk->rl, line);
+
+	if (!pblk_line_init_bb(pblk, line, 0)) {
+		list_add(&line->list, &l_mg->free_list);
+		return -EINTR;
+	}
+
+	return 0;
+}
+
+void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line)
+{
+	mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	line->map_bitmap = NULL;
+	line->smeta = NULL;
+	line->emeta = NULL;
+}
+
+struct pblk_line *pblk_line_get(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line *line = NULL;
+	int bit;
+
+	lockdep_assert_held(&l_mg->free_lock);
+
+retry_get:
+	if (list_empty(&l_mg->free_list)) {
+		pr_err("pblk: no free lines\n");
+		goto out;
+	}
+
+	line = list_first_entry(&l_mg->free_list, struct pblk_line, list);
+	list_del(&line->list);
+	l_mg->nr_free_lines--;
+
+	bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
+	if (unlikely(bit >= lm->blk_per_line)) {
+		spin_lock(&line->lock);
+		line->state = PBLK_LINESTATE_BAD;
+		spin_unlock(&line->lock);
+
+		list_add_tail(&line->list, &l_mg->bad_list);
+
+		pr_debug("pblk: line %d is bad\n", line->id);
+		goto retry_get;
+	}
+
+	if (pblk_line_prepare(pblk, line)) {
+		pr_err("pblk: failed to prepare line %d\n", line->id);
+		list_add(&line->list, &l_mg->free_list);
+		return NULL;
+	}
+
+out:
+	return line;
+}
+
+static struct pblk_line *pblk_line_retry(struct pblk *pblk,
+					 struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *retry_line;
+
+	spin_lock(&l_mg->free_lock);
+	retry_line = pblk_line_get(pblk);
+	if (!retry_line) {
+		spin_unlock(&l_mg->free_lock);
+		return NULL;
+	}
+
+	retry_line->smeta = line->smeta;
+	retry_line->emeta = line->emeta;
+	retry_line->meta_line = line->meta_line;
+	retry_line->map_bitmap = line->map_bitmap;
+	retry_line->invalid_bitmap = line->invalid_bitmap;
+
+	line->map_bitmap = NULL;
+	line->invalid_bitmap = NULL;
+	line->smeta = NULL;
+	line->emeta = NULL;
+	spin_unlock(&l_mg->free_lock);
+
+	if (pblk_line_erase(pblk, retry_line))
+		return NULL;
+
+	pblk_rl_free_lines_dec(&pblk->rl, retry_line);
+
+	l_mg->data_line = retry_line;
+
+	return retry_line;
+}
+
+struct pblk_line *pblk_line_get_first_data(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *line;
+	int meta_line;
+	int is_next = 0;
+
+	spin_lock(&l_mg->free_lock);
+	line = pblk_line_get(pblk);
+	if (!line) {
+		spin_unlock(&l_mg->free_lock);
+		return NULL;
+	}
+
+	line->seq_nr = l_mg->d_seq_nr++;
+	line->type = PBLK_LINETYPE_DATA;
+	l_mg->data_line = line;
+
+	meta_line = find_first_zero_bit(&l_mg->meta_bitmap, PBLK_DATA_LINES);
+	set_bit(meta_line, &l_mg->meta_bitmap);
+	line->smeta = l_mg->sline_meta[meta_line].meta;
+	line->emeta = l_mg->eline_meta[meta_line].meta;
+	line->meta_line = meta_line;
+
+	/* Allocate next line for preparation */
+	l_mg->data_next = pblk_line_get(pblk);
+	if (l_mg->data_next) {
+		l_mg->data_next->seq_nr = l_mg->d_seq_nr++;
+		l_mg->data_next->type = PBLK_LINETYPE_DATA;
+		is_next = 1;
+	}
+	spin_unlock(&l_mg->free_lock);
+
+	pblk_rl_free_lines_dec(&pblk->rl, line);
+	if (is_next)
+		pblk_rl_free_lines_dec(&pblk->rl, l_mg->data_next);
+
+	if (pblk_line_erase(pblk, line))
+		return NULL;
+
+retry_setup:
+	if (!pblk_line_set_metadata(pblk, line, NULL)) {
+		line = pblk_line_retry(pblk, line);
+		if (!line)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	if (!pblk_line_init_bb(pblk, line, 1)) {
+		line = pblk_line_retry(pblk, line);
+		if (!line)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	return line;
+}
+
+struct pblk_line *pblk_line_replace_data(struct pblk *pblk)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *cur, *new;
+	unsigned int left_seblks;
+	int meta_line;
+	int is_next = 0;
+
+	cur = l_mg->data_line;
+	new = l_mg->data_next;
+	if (!new)
+		return NULL;
+	l_mg->data_line = new;
+
+retry_line:
+	left_seblks = atomic_read(&new->left_seblks);
+	if (left_seblks) {
+		/* If line is not fully erased, erase it */
+		if (new->left_eblks) {
+			if (pblk_line_erase(pblk, new))
+				return NULL;
+		} else {
+			io_schedule();
+		}
+		goto retry_line;
+	}
+
+	spin_lock(&l_mg->free_lock);
+	/* Allocate next line for preparation */
+	l_mg->data_next = pblk_line_get(pblk);
+	if (l_mg->data_next) {
+		l_mg->data_next->seq_nr = l_mg->d_seq_nr++;
+		l_mg->data_next->type = PBLK_LINETYPE_DATA;
+		is_next = 1;
+	}
+
+retry_meta:
+	meta_line = find_first_zero_bit(&l_mg->meta_bitmap, PBLK_DATA_LINES);
+	if (meta_line == PBLK_DATA_LINES) {
+		spin_unlock(&l_mg->free_lock);
+		io_schedule();
+		spin_lock(&l_mg->free_lock);
+		goto retry_meta;
+	}
+
+	set_bit(meta_line, &l_mg->meta_bitmap);
+	new->smeta = l_mg->sline_meta[meta_line].meta;
+	new->emeta = l_mg->eline_meta[meta_line].meta;
+	new->meta_line = meta_line;
+
+	memset(new->smeta, 0, lm->smeta_len);
+	memset(new->emeta, 0, lm->emeta_len);
+	spin_unlock(&l_mg->free_lock);
+
+	if (is_next)
+		pblk_rl_free_lines_dec(&pblk->rl, l_mg->data_next);
+
+retry_setup:
+	if (!pblk_line_set_metadata(pblk, new, cur)) {
+		new = pblk_line_retry(pblk, new);
+		if (new)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	if (!pblk_line_init_bb(pblk, new, 1)) {
+		new = pblk_line_retry(pblk, new);
+		if (!new)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	return new;
+}
+
+void pblk_line_free(struct pblk *pblk, struct pblk_line *line)
+{
+	if (line->map_bitmap)
+		mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	if (line->invalid_bitmap)
+		mempool_free(line->invalid_bitmap, pblk->line_meta_pool);
+
+	line->map_bitmap = NULL;
+	line->invalid_bitmap = NULL;
+}
+
+void pblk_line_put(struct kref *ref)
+{
+	struct pblk_line *line = container_of(ref, struct pblk_line, ref);
+	struct pblk *pblk = line->pblk;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+
+	spin_lock(&line->lock);
+	WARN_ON(line->state != PBLK_LINESTATE_GC);
+	line->state = PBLK_LINESTATE_FREE;
+	line->gc_group = PBLK_LINEGC_NONE;
+	pblk_line_free(pblk, line);
+	spin_unlock(&line->lock);
+
+	spin_lock(&l_mg->free_lock);
+	list_add_tail(&line->list, &l_mg->free_list);
+	l_mg->nr_free_lines++;
+	spin_unlock(&l_mg->free_lock);
+
+	pblk_rl_free_lines_inc(&pblk->rl, line);
+}
+
+int pblk_blk_erase_async(struct pblk *pblk, struct ppa_addr ppa)
+{
+	struct nvm_rq *rqd;
+	int err;
+
+	rqd = mempool_alloc(pblk->r_rq_pool, GFP_KERNEL);
+	memset(rqd, 0, pblk_r_rq_size);
+
+	pblk_setup_e_rq(pblk, rqd, ppa);
+
+	rqd->end_io = pblk_end_io_erase;
+	rqd->private = pblk;
+
+	/* The write thread schedules erases so that it minimizes disturbances
+	 * with writes. Thus, there is no need to take the LUN semaphore.
+	 */
+	err = pblk_submit_io(pblk, rqd);
+	if (err) {
+		struct nvm_tgt_dev *dev = pblk->dev;
+		struct nvm_geo *geo = &dev->geo;
+
+		pr_err("pblk: could not async erase line:%d,blk:%d\n",
+					pblk_dev_ppa_to_line(ppa),
+					pblk_dev_ppa_to_pos(geo, ppa));
+	}
+
+	return err;
+}
+
+struct pblk_line *pblk_line_get_data(struct pblk *pblk)
+{
+	return pblk->l_mg.data_line;
+}
+
+struct pblk_line *pblk_line_get_data_next(struct pblk *pblk)
+{
+	return pblk->l_mg.data_next;
+}
+
+int pblk_line_is_full(struct pblk_line *line)
+{
+	return (line->left_msecs == 0);
+}
+
+void pblk_line_close(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list;
+
+	line->emeta->crc = cpu_to_le32(pblk_calc_emeta_crc(pblk, line->emeta));
+
+	if (pblk_line_submit_emeta_io(pblk, line, line->cur_sec, WRITE))
+		pr_err("pblk: line %d close I/O failed\n", line->id);
+
+	WARN(!bitmap_full(line->map_bitmap, line->sec_in_line),
+				"pblk: corrupt closed line %d\n", line->id);
+
+	spin_lock(&l_mg->free_lock);
+	WARN_ON(!test_and_clear_bit(line->meta_line, &l_mg->meta_bitmap));
+	spin_unlock(&l_mg->free_lock);
+
+	spin_lock(&l_mg->gc_lock);
+	spin_lock(&line->lock);
+	WARN_ON(line->state != PBLK_LINESTATE_OPEN);
+	line->state = PBLK_LINESTATE_CLOSED;
+	move_list = pblk_line_gc_list(pblk, line);
+
+	list_add_tail(&line->list, move_list);
+
+	mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	line->map_bitmap = NULL;
+	line->smeta = NULL;
+	line->emeta = NULL;
+
+	spin_unlock(&line->lock);
+	spin_unlock(&l_mg->gc_lock);
+}
+
+void pblk_line_close_ws(struct work_struct *work)
+{
+	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
+									ws);
+	struct pblk *pblk = line_ws->pblk;
+	struct pblk_line *line = line_ws->line;
+
+	pblk_line_close(pblk, line);
+	mempool_free(line_ws, pblk->line_ws_pool);
+}
+
+void pblk_line_mark_bb(struct work_struct *work)
+{
+	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
+									ws);
+	struct pblk *pblk = line_ws->pblk;
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct ppa_addr *ppa = line_ws->priv;
+	int ret;
+
+	ret = nvm_set_tgt_bb_tbl(dev, ppa, 1, NVM_BLK_T_GRWN_BAD);
+	if (ret) {
+		struct pblk_line *line;
+		int pos;
+
+		line = &pblk->lines[pblk_dev_ppa_to_line(*ppa)];
+		pos = pblk_dev_ppa_to_pos(&dev->geo, *ppa);
+
+		pr_err("pblk: failed to mark bb, line:%d, pos:%d\n",
+				line->id, pos);
+	}
+
+	kfree(ppa);
+	mempool_free(line_ws, pblk->line_ws_pool);
+}
+
+void pblk_line_run_ws(struct pblk *pblk, struct pblk_line *line, void *priv,
+		      void (*work)(struct work_struct *))
+{
+	struct pblk_line_ws *line_ws;
+
+	line_ws = mempool_alloc(pblk->line_ws_pool, GFP_ATOMIC);
+	if (!line_ws)
+		return;
+
+	line_ws->pblk = pblk;
+	line_ws->line = line;
+	line_ws->priv = priv;
+
+	INIT_WORK(&line_ws->ws, work);
+	queue_work(pblk->kw_wq, &line_ws->ws);
+}
+
+void pblk_down_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
+		  unsigned long *lun_bitmap)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_lun *rlun;
+	int lun_id = ppa_list[0].g.ch * geo->luns_per_chnl + ppa_list[0].g.lun;
+	int ret;
+
+	/*
+	 * Only send one inflight I/O per LUN. Since we map at a page
+	 * granurality, all ppas in the I/O will map to the same LUN
+	 */
+#ifdef CONFIG_NVM_DEBUG
+	int i;
+
+	for (i = 1; i < nr_ppas; i++)
+		WARN_ON(ppa_list[0].g.lun != ppa_list[i].g.lun ||
+				ppa_list[0].g.ch != ppa_list[i].g.ch);
+#endif
+	/* If the LUN has been locked for this same request, do no attempt to
+	 * lock it again
+	 */
+	if (test_and_set_bit(lun_id, lun_bitmap))
+		return;
+
+	rlun = &pblk->luns[lun_id];
+	ret = down_timeout(&rlun->wr_sem, msecs_to_jiffies(5000));
+	if (ret) {
+		switch (ret) {
+		case -ETIME:
+			pr_err("pblk: lun semaphore timed out\n");
+			break;
+		case -EINTR:
+			pr_err("pblk: lun semaphore timed out\n");
+			break;
+		}
+	}
+}
+
+void pblk_up_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
+		unsigned long *lun_bitmap)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_lun *rlun;
+	int nr_luns = geo->nr_luns;
+	int bit = -1;
+
+	while ((bit = find_next_bit(lun_bitmap, nr_luns, bit + 1)) < nr_luns) {
+		rlun = &pblk->luns[bit];
+		up(&rlun->wr_sem);
+	}
+
+	kfree(lun_bitmap);
+}
+
+void pblk_update_map(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
+{
+	struct ppa_addr l2p_ppa;
+
+	/* logic error: lba out-of-bounds. Ignore update */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN(1, "pblk: corrupted L2P map request\n");
+		return;
+	}
+
+	spin_lock(&pblk->trans_lock);
+	l2p_ppa = pblk_trans_map_get(pblk, lba);
+
+	if (!pblk_addr_in_cache(l2p_ppa) && !pblk_ppa_empty(l2p_ppa))
+		pblk_map_invalidate(pblk, l2p_ppa);
+
+	pblk_trans_map_set(pblk, lba, ppa);
+	spin_unlock(&pblk->trans_lock);
+}
+
+void pblk_update_map_cache(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
+{
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a cache address */
+	BUG_ON(!pblk_addr_in_cache(ppa));
+	BUG_ON(pblk_rb_pos_oob(&pblk->rwb, pblk_addr_to_cacheline(ppa)));
+#endif
+
+	pblk_update_map(pblk, lba, ppa);
+}
+
+int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa,
+		       struct pblk_line *gc_line)
+{
+	struct ppa_addr l2p_ppa;
+	int ret = 1;
+
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a cache address */
+	BUG_ON(!pblk_addr_in_cache(ppa));
+	BUG_ON(pblk_rb_pos_oob(&pblk->rwb, pblk_addr_to_cacheline(ppa)));
+#endif
+
+	/* logic error: lba out-of-bounds. Ignore update */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN(1, "pblk: corrupted L2P map request\n");
+		return 0;
+	}
+
+	spin_lock(&pblk->trans_lock);
+	l2p_ppa = pblk_trans_map_get(pblk, lba);
+
+	/* Prevent updated entries to be overwritten by GC */
+	if (pblk_addr_in_cache(l2p_ppa) || pblk_ppa_empty(l2p_ppa) ||
+				pblk_tgt_ppa_to_line(l2p_ppa) != gc_line->id) {
+		ret = 0;
+		goto out;
+	}
+
+	pblk_trans_map_set(pblk, lba, ppa);
+out:
+	spin_unlock(&pblk->trans_lock);
+	return ret;
+}
+
+void pblk_update_map_dev(struct pblk *pblk, sector_t lba, struct ppa_addr ppa,
+			 struct ppa_addr entry_line)
+{
+	struct ppa_addr l2p_line;
+
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a device address */
+	BUG_ON(pblk_addr_in_cache(ppa));
+#endif
+	/* Invalidate and discard padded entries */
+	if (lba == ADDR_EMPTY) {
+#ifdef CONFIG_NVM_DEBUG
+		atomic_long_inc(&pblk->padded_wb);
+#endif
+		pblk_map_invalidate(pblk, ppa);
+		return;
+	}
+
+	/* logic error: lba out-of-bounds. Ignore update */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN(1, "pblk: corrupted L2P map request\n");
+		return;
+	}
+
+	spin_lock(&pblk->trans_lock);
+	l2p_line = pblk_trans_map_get(pblk, lba);
+
+	/* Do not update L2P if the cacheline has been updated. In this case,
+	 * the mapped ppa must be invalidated
+	 */
+	if (l2p_line.ppa != entry_line.ppa) {
+		if (!pblk_ppa_empty(ppa))
+			pblk_map_invalidate(pblk, ppa);
+		goto out;
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	WARN_ON(!pblk_addr_in_cache(l2p_line) && !pblk_ppa_empty(l2p_line));
+#endif
+
+	pblk_trans_map_set(pblk, lba, ppa);
+out:
+	spin_unlock(&pblk->trans_lock);
+}
+
+void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
+			 sector_t blba, int nr_secs)
+{
+	int i;
+
+	spin_lock(&pblk->trans_lock);
+	for (i = 0; i < nr_secs; i++)
+		ppas[i] = pblk_trans_map_get(pblk, blba + i);
+	spin_unlock(&pblk->trans_lock);
+}
+
+void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
+			  u64 *lba_list, int nr_secs)
+{
+	sector_t lba;
+	int i;
+
+	spin_lock(&pblk->trans_lock);
+	for (i = 0; i < nr_secs; i++) {
+		lba = lba_list[i];
+		if (lba == ADDR_EMPTY) {
+			ppas[i].ppa = ADDR_EMPTY;
+		} else {
+			/* logic error: lba out-of-bounds. Ignore update */
+			if (!(lba < pblk->rl.nr_secs)) {
+				WARN(1, "pblk: corrupted L2P map request\n");
+				continue;
+			}
+			ppas[i] = pblk_trans_map_get(pblk, lba);
+		}
+	}
+	spin_unlock(&pblk->trans_lock);
+}