[dm-devel] [PATCH 3/3] dm-zoned: properly handle backing device failure
Dmitry Fomichev
dmitry.fomichev at wdc.com
Tue Aug 6 01:06:25 UTC 2019
dm-zoned is observed to lock up or livelock in case of hardware
failure or some misconfiguration of the backing zoned device.
This patch adds a new function in the target code that checks the
status of the backing device request queue. If it goes to dying state,
the health check code marks dm-zoned DM target read-only and begins
to reject any further incoming I/O. In order to timely detect backing
device failure, this new function is called in the request mapping
path, at the beginning of every reclaim run and before performing any
metadata I/O.
The proper way out of this situation is to do
dmsetup remove <dm-zoned target>
and recreate the target when the problem with the backing device
is resolved.
Fixes: 3b1a94c88b79 ("dm zoned: drive-managed zoned block device target")
Cc: stable at vger.kernel.org
Signed-off-by: Dmitry Fomichev <dmitry.fomichev at wdc.com>
---
drivers/md/dm-zoned-metadata.c | 51 +++++++++++++++++++++++++++-------
drivers/md/dm-zoned-reclaim.c | 18 ++++++++++--
drivers/md/dm-zoned-target.c | 50 +++++++++++++++++++++++++++++++--
drivers/md/dm-zoned.h | 10 +++++++
4 files changed, 115 insertions(+), 14 deletions(-)
diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index 6b7fbbd735ef..2a5bc51fd6d5 100644
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -403,15 +403,18 @@ static struct dmz_mblock *dmz_get_mblock_slow(struct dmz_metadata *zmd,
sector_t block = zmd->sb[zmd->mblk_primary].block + mblk_no;
struct bio *bio;
+ if (dmz_bdev_is_dying(zmd->dev))
+ return ERR_PTR(-EIO);
+
/* Get a new block and a BIO to read it */
mblk = dmz_alloc_mblock(zmd, mblk_no);
if (!mblk)
- return NULL;
+ return ERR_PTR(-ENOMEM);
bio = bio_alloc(GFP_NOIO, 1);
if (!bio) {
dmz_free_mblock(zmd, mblk);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
spin_lock(&zmd->mblk_lock);
@@ -542,8 +545,8 @@ static struct dmz_mblock *dmz_get_mblock(struct dmz_metadata *zmd,
if (!mblk) {
/* Cache miss: read the block from disk */
mblk = dmz_get_mblock_slow(zmd, mblk_no);
- if (!mblk)
- return ERR_PTR(-ENOMEM);
+ if (IS_ERR(mblk))
+ return mblk;
}
/* Wait for on-going read I/O and check for error */
@@ -571,16 +574,19 @@ static void dmz_dirty_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk)
/*
* Issue a metadata block write BIO.
*/
-static void dmz_write_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk,
- unsigned int set)
+static int dmz_write_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk,
+ unsigned int set)
{
sector_t block = zmd->sb[set].block + mblk->no;
struct bio *bio;
+ if (dmz_bdev_is_dying(zmd->dev))
+ return -EIO;
+
bio = bio_alloc(GFP_NOIO, 1);
if (!bio) {
set_bit(DMZ_META_ERROR, &mblk->state);
- return;
+ return -ENOMEM;
}
set_bit(DMZ_META_WRITING, &mblk->state);
@@ -592,6 +598,8 @@ static void dmz_write_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk,
bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_META | REQ_PRIO);
bio_add_page(bio, mblk->page, DMZ_BLOCK_SIZE, 0);
submit_bio(bio);
+
+ return 0;
}
/*
@@ -603,6 +611,9 @@ static int dmz_rdwr_block(struct dmz_metadata *zmd, int op, sector_t block,
struct bio *bio;
int ret;
+ if (dmz_bdev_is_dying(zmd->dev))
+ return -EIO;
+
bio = bio_alloc(GFP_NOIO, 1);
if (!bio)
return -ENOMEM;
@@ -660,22 +671,29 @@ static int dmz_write_dirty_mblocks(struct dmz_metadata *zmd,
{
struct dmz_mblock *mblk;
struct blk_plug plug;
- int ret = 0;
+ int ret = 0, nr_mblks_submitted = 0;
/* Issue writes */
blk_start_plug(&plug);
- list_for_each_entry(mblk, write_list, link)
- dmz_write_mblock(zmd, mblk, set);
+ list_for_each_entry(mblk, write_list, link) {
+ ret = dmz_write_mblock(zmd, mblk, set);
+ if (ret)
+ break;
+ nr_mblks_submitted++;
+ }
blk_finish_plug(&plug);
/* Wait for completion */
list_for_each_entry(mblk, write_list, link) {
+ if (!nr_mblks_submitted)
+ break;
wait_on_bit_io(&mblk->state, DMZ_META_WRITING,
TASK_UNINTERRUPTIBLE);
if (test_bit(DMZ_META_ERROR, &mblk->state)) {
clear_bit(DMZ_META_ERROR, &mblk->state);
ret = -EIO;
}
+ nr_mblks_submitted--;
}
/* Flush drive cache (this will also sync data) */
@@ -737,6 +755,11 @@ int dmz_flush_metadata(struct dmz_metadata *zmd)
*/
dmz_lock_flush(zmd);
+ if (dmz_bdev_is_dying(zmd->dev)) {
+ ret = -EIO;
+ goto out;
+ }
+
/* Get dirty blocks */
spin_lock(&zmd->mblk_lock);
list_splice_init(&zmd->mblk_dirty_list, &write_list);
@@ -1632,6 +1655,10 @@ struct dm_zone *dmz_get_chunk_mapping(struct dmz_metadata *zmd, unsigned int chu
/* Allocate a random zone */
dzone = dmz_alloc_zone(zmd, DMZ_ALLOC_RND);
if (!dzone) {
+ if (dmz_bdev_is_dying(zmd->dev)) {
+ dzone = ERR_PTR(-EIO);
+ goto out;
+ }
dmz_wait_for_free_zones(zmd);
goto again;
}
@@ -1729,6 +1756,10 @@ struct dm_zone *dmz_get_chunk_buffer(struct dmz_metadata *zmd,
/* Allocate a random zone */
bzone = dmz_alloc_zone(zmd, DMZ_ALLOC_RND);
if (!bzone) {
+ if (dmz_bdev_is_dying(zmd->dev)) {
+ bzone = ERR_PTR(-EIO);
+ goto out;
+ }
dmz_wait_for_free_zones(zmd);
goto again;
}
diff --git a/drivers/md/dm-zoned-reclaim.c b/drivers/md/dm-zoned-reclaim.c
index 26e34493a2db..d240d7ca8a8a 100644
--- a/drivers/md/dm-zoned-reclaim.c
+++ b/drivers/md/dm-zoned-reclaim.c
@@ -38,7 +38,7 @@ enum {
/*
* Number of seconds of target BIO inactivity to consider the target idle.
*/
-#define DMZ_IDLE_PERIOD (10UL * HZ)
+#define DMZ_IDLE_PERIOD (10UL * HZ)
/*
* Percentage of unmapped (free) random zones below which reclaim starts
@@ -135,6 +135,9 @@ static int dmz_reclaim_copy(struct dmz_reclaim *zrc,
set_bit(DM_KCOPYD_WRITE_SEQ, &flags);
while (block < end_block) {
+ if (dev->flags & DMZ_BDEV_DYING)
+ return -EIO;
+
/* Get a valid region from the source zone */
ret = dmz_first_valid_block(zmd, src_zone, &block);
if (ret <= 0)
@@ -452,6 +455,9 @@ static void dmz_reclaim_work(struct work_struct *work)
unsigned int p_unmap_rnd;
int ret;
+ if (dmz_bdev_is_dying(zrc->dev))
+ return;
+
if (!dmz_should_reclaim(zrc)) {
mod_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD);
return;
@@ -481,8 +487,16 @@ static void dmz_reclaim_work(struct work_struct *work)
p_unmap_rnd, nr_unmap_rnd, nr_rnd);
ret = dmz_do_reclaim(zrc);
- if (ret)
+ if (ret) {
dmz_dev_debug(zrc->dev, "Reclaim error %d\n", ret);
+ if (ret == -EIO)
+ /*
+ * LLD might be performing some error handling sequence
+ * at the underlying device. To not interfere, do not
+ * attempt to schedule the next reclaim run immediately.
+ */
+ return;
+ }
dmz_schedule_reclaim(zrc);
}
diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
index c1992034c099..c40c18f7fd64 100644
--- a/drivers/md/dm-zoned-target.c
+++ b/drivers/md/dm-zoned-target.c
@@ -134,6 +134,8 @@ static int dmz_submit_bio(struct dmz_target *dmz, struct dm_zone *zone,
refcount_inc(&bioctx->ref);
generic_make_request(clone);
+ if (clone->bi_status == BLK_STS_IOERR)
+ return -EIO;
if (bio_op(bio) == REQ_OP_WRITE && dmz_is_seq(zone))
zone->wp_block += nr_blocks;
@@ -278,8 +280,8 @@ static int dmz_handle_buffered_write(struct dmz_target *dmz,
/* Get the buffer zone. One will be allocated if needed */
bzone = dmz_get_chunk_buffer(zmd, zone);
- if (!bzone)
- return -ENOSPC;
+ if (IS_ERR(bzone))
+ return PTR_ERR(bzone);
if (dmz_is_readonly(bzone))
return -EROFS;
@@ -390,6 +392,11 @@ static void dmz_handle_bio(struct dmz_target *dmz, struct dm_chunk_work *cw,
dmz_lock_metadata(zmd);
+ if (dmz->dev->flags & DMZ_BDEV_DYING) {
+ ret = -EIO;
+ goto out;
+ }
+
/*
* Get the data zone mapping the chunk. There may be no
* mapping for read and discard. If a mapping is obtained,
@@ -494,6 +501,8 @@ static void dmz_flush_work(struct work_struct *work)
/* Flush dirty metadata blocks */
ret = dmz_flush_metadata(dmz->metadata);
+ if (ret)
+ dmz_dev_debug(dmz->dev, "Metadata flush failed, rc=%d\n", ret);
/* Process queued flush requests */
while (1) {
@@ -557,6 +566,37 @@ static int dmz_queue_chunk_work(struct dmz_target *dmz, struct bio *bio)
return ret;
}
+/*
+ * Check the backing device availability. If it's on the way out,
+ * start failing I/O. Reclaim and metadata components also call this
+ * function to cleanly abort operation in the event of such failure.
+ */
+bool dmz_bdev_is_dying(struct dmz_dev *dmz_dev)
+{
+ struct gendisk *disk;
+ bool dying = dmz_dev->flags & DMZ_BDEV_DYING;
+
+ if (!dying) {
+ disk = dmz_dev->bdev->bd_disk;
+ if (blk_queue_dying(bdev_get_queue(dmz_dev->bdev))) {
+ dmz_dev_warn(dmz_dev, "Backing device queue dying");
+ dying = true;
+ } else if (disk->fops->check_events) {
+ if (disk->fops->check_events(disk, 0) &
+ DISK_EVENT_MEDIA_CHANGE) {
+ dmz_dev_warn(dmz_dev, "Backing device offline");
+ dying = true;
+ }
+ }
+ if (dying) {
+ dmz_dev->flags |= DMZ_BDEV_DYING;
+ set_disk_ro(dmz_dev->bdev->bd_disk, 1);
+ }
+ }
+
+ return dying;
+}
+
/*
* Process a new BIO.
*/
@@ -570,6 +610,9 @@ static int dmz_map(struct dm_target *ti, struct bio *bio)
sector_t chunk_sector;
int ret;
+ if (dmz_bdev_is_dying(dmz->dev))
+ return DM_MAPIO_KILL;
+
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,
(unsigned long long)dmz_bio_chunk(dmz->dev, bio),
@@ -866,6 +909,9 @@ static int dmz_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
{
struct dmz_target *dmz = ti->private;
+ if (dmz_bdev_is_dying(dmz->dev))
+ return -ENODEV;
+
*bdev = dmz->dev->bdev;
return 0;
diff --git a/drivers/md/dm-zoned.h b/drivers/md/dm-zoned.h
index 1a3b06de2c00..d8e70b0ade35 100644
--- a/drivers/md/dm-zoned.h
+++ b/drivers/md/dm-zoned.h
@@ -57,6 +57,8 @@ struct dmz_dev {
unsigned int nr_zones;
+ unsigned int flags;
+
sector_t zone_nr_sectors;
unsigned int zone_nr_sectors_shift;
@@ -68,6 +70,9 @@ struct dmz_dev {
(dev)->zone_nr_sectors_shift)
#define dmz_chunk_block(dev, b) ((b) & ((dev)->zone_nr_blocks - 1))
+/* Device flags. */
+#define DMZ_BDEV_DYING (1 << 0)
+
/*
* Zone descriptor.
*/
@@ -246,4 +251,9 @@ void dmz_resume_reclaim(struct dmz_reclaim *zrc);
void dmz_reclaim_bio_acc(struct dmz_reclaim *zrc);
void dmz_schedule_reclaim(struct dmz_reclaim *zrc);
+/*
+ * Functions defined in dm-zoned-target.c
+ */
+bool dmz_bdev_is_dying(struct dmz_dev *dmz_dev);
+
#endif /* DM_ZONED_H */
--
2.21.0
More information about the dm-devel
mailing list