Re: [PATCH 14/18] lightnvm: pblk: GC error handling

On 14 Mar 2019, at 17.04, Igor Konopko [off-list ref] wrote:

Currently when there is an IO error (or similar) on GC read path, pblk
still moves this line to free state, what leads to data mismatch issue.

This patch adds a handling for such an error - after that changes this
line will be returned to closed state so it can be still in use
for reading - at least we will be able to return error status to user
when user tries to read such a data.

Signed-off-by: Igor Konopko <redacted>
---
drivers/lightnvm/pblk-core.c | 8 ++++++++
drivers/lightnvm/pblk-gc.c   | 5 ++---
drivers/lightnvm/pblk-read.c | 1 -
drivers/lightnvm/pblk.h      | 2 ++
4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 4d5cd99..6817f8f 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c

@@ -1786,6 +1786,14 @@ static void __pblk_line_put(struct pblk *pblk, struct pblk_line *line)

	spin_lock(&line->lock);
	WARN_ON(line->state != PBLK_LINESTATE_GC);
+	if (line->w_err_gc->has_gc_err) {
+		spin_unlock(&line->lock);
+		pblk_err(pblk, "line %d had errors during GC\n", line->id);
+		pblk_put_line_back(pblk, line);
+		line->w_err_gc->has_gc_err = 0;
+		return;
+	}
+
	line->state = PBLK_LINESTATE_FREE;
	trace_pblk_line_state(pblk_disk_name(pblk), line->id,
					line->state);

diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
index e23b192..63ee205 100644
--- a/drivers/lightnvm/pblk-gc.c
+++ b/drivers/lightnvm/pblk-gc.c

@@ -59,7 +59,7 @@ static void pblk_gc_writer_kick(struct pblk_gc *gc)

	wake_up_process(gc->gc_writer_ts);
}

-static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
+void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
{
	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
	struct list_head *move_list;

@@ -98,8 +98,7 @@ static void pblk_gc_line_ws(struct work_struct *work)

	/* Read from GC victim block */
	ret = pblk_submit_read_gc(pblk, gc_rq);
	if (ret) {
-		pblk_err(pblk, "failed GC read in line:%d (err:%d)\n",
-								line->id, ret);
+		line->w_err_gc->has_gc_err = 1;
		goto out;
	}

diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
index 54422a2..6a77c24 100644
--- a/drivers/lightnvm/pblk-read.c
+++ b/drivers/lightnvm/pblk-read.c

@@ -475,7 +475,6 @@ int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq)

	if (pblk_submit_io_sync(pblk, &rqd)) {
		ret = -EIO;
-		pblk_err(pblk, "GC read request failed\n");
		goto err_free_bio;
	}

diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index 5d1040a..52002f5 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h

@@ -427,6 +427,7 @@ struct pblk_smeta {

struct pblk_w_err_gc {
	int has_write_err;
+	int has_gc_err;
	__le64 *lba_list;
};

@@ -909,6 +910,7 @@ void pblk_gc_free_full_lines(struct pblk *pblk);

void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
			      int *gc_active);
int pblk_gc_sysfs_force(struct pblk *pblk, int force);
+void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line);

/*
 * pblk rate limiter
--
2.9.5