[PATCH 4.19 82/98] dm zoned: improve error handling in i/o map code

Greg Kroah-Hartman
2019-08-27T07:58:27Z

From: Dmitry Fomichev <dmitry.fomichev@wdc.com>

commit d7428c50118e739e672656c28d2b26b09375d4e0 upstream.

Some errors are ignored in the I/O path during queueing chunks
for processing by chunk works. Since at least these errors are
transient in nature, it should be possible to retry the failed
incoming commands.

The fix -

Errors that can happen while queueing chunks are carried upwards
to the main mapping function and it now returns DM_MAPIO_REQUEUE
for any incoming requests that can not be properly queued.

Error logging/debug messages are added where needed.

Fixes: 3b1a94c88b79 ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-zoned-target.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)

--- a/drivers/md/dm-zoned-target.c
+++ b/drivers/md/dm-zoned-target.c
@@ -513,22 +513,24 @@ static void dmz_flush_work(struct work_s
* Get a chunk work and start it to process a new BIO.
* If the BIO chunk has no work yet, create one.
*/
-static void dmz_queue_chunk_work(struct dmz_target *dmz, struct bio *bio)
+static int dmz_queue_chunk_work(struct dmz_target *dmz, struct bio *bio)
{
unsigned int chunk = dmz_bio_chunk(dmz->dev, bio);
struct dm_chunk_work *cw;
+ int ret = 0;

mutex_lock(&dmz->chunk_lock);

/* Get the BIO chunk work. If one is not active yet, create one */
cw = radix_tree_lookup(&dmz->chunk_rxtree, chunk);
if (!cw) {
- int ret;

/* Create a new chunk work */
cw = kmalloc(sizeof(struct dm_chunk_work), GFP_NOIO);
- if (!cw)
+ if (unlikely(!cw)) {
+ ret = -ENOMEM;
goto out;
+ }

INIT_WORK(&cw->work, dmz_chunk_work);
atomic_set(&cw->refcount, 0);
@@ -539,7 +541,6 @@ static void dmz_queue_chunk_work(struct
ret = radix_tree_insert(&dmz->chunk_rxtree, chunk, cw);
if (unlikely(ret)) {
kfree(cw);
- cw = NULL;
goto out;
}
}
@@ -547,10 +548,12 @@ static void dmz_queue_chunk_work(struct
bio_list_add(&cw->bio_list, bio);
dmz_get_chunk_work(cw);

+ dmz_reclaim_bio_acc(dmz->reclaim);
if (queue_work(dmz->chunk_wq, &cw->work))
dmz_get_chunk_work(cw);
out:
mutex_unlock(&dmz->chunk_lock);
+ return ret;
}

/*
@@ -564,6 +567,7 @@ static int dmz_map(struct dm_target *ti,
sector_t sector = bio->bi_iter.bi_sector;
unsigned int nr_sectors = bio_sectors(bio);
sector_t chunk_sector;
+ int ret;

dmz_dev_debug(dev, "BIO op %d sector %llu + %u => chunk %llu, block %llu, %u blocks",
bio_op(bio), (unsigned long long)sector, nr_sectors,
@@ -601,8 +605,14 @@ static int dmz_map(struct dm_target *ti,
dm_accept_partial_bio(bio, dev->zone_nr_sectors - chunk_sector);

/* Now ready to handle this BIO */
- dmz_reclaim_bio_acc(dmz->reclaim);
- dmz_queue_chunk_work(dmz, bio);
+ ret = dmz_queue_chunk_work(dmz, bio);
+ if (ret) {
+ dmz_dev_debug(dmz->dev,
+ "BIO op %d, can't process chunk %llu, err %i\n",
+ bio_op(bio), (u64)dmz_bio_chunk(dmz->dev, bio),
+ ret);
+ return DM_MAPIO_REQUEUE;
+ }

return DM_MAPIO_SUBMITTED;
}