[PATCH 5.5 140/367] dm zoned: support zone sizes smaller than 128MiB

Greg Kroah-Hartman
2020-02-10T13:03:51Z

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

commit b39962950339912978484cdac50069258545d753 upstream.

dm-zoned is observed to log failed kernel assertions and not work
correctly when operating against a device with a zone size smaller
than 128MiB (e.g. 32768 bits per 4K block). The reason is that the
bitmap size per zone is calculated as zero with such a small zone
size. Fix this problem and also make the code related to zone bitmap
management be able to handle per zone bitmaps smaller than a single
block.

A dm-zoned-tools patch is required to properly format dm-zoned devices
with zone sizes smaller than 128MiB.

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-metadata.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -134,6 +134,7 @@ struct dmz_metadata {

sector_t zone_bitmap_size;
unsigned int zone_nr_bitmap_blocks;
+ unsigned int zone_bits_per_mblk;

unsigned int nr_bitmap_blocks;
unsigned int nr_map_blocks;
@@ -1161,7 +1162,10 @@ static int dmz_init_zones(struct dmz_met

/* Init */
zmd->zone_bitmap_size = dev->zone_nr_blocks >> 3;
- zmd->zone_nr_bitmap_blocks = zmd->zone_bitmap_size >> DMZ_BLOCK_SHIFT;
+ zmd->zone_nr_bitmap_blocks =
+ max_t(sector_t, 1, zmd->zone_bitmap_size >> DMZ_BLOCK_SHIFT);
+ zmd->zone_bits_per_mblk = min_t(sector_t, dev->zone_nr_blocks,
+ DMZ_BLOCK_SIZE_BITS);

/* Allocate zone array */
zmd->zones = kcalloc(dev->nr_zones, sizeof(struct dm_zone), GFP_KERNEL);
@@ -1956,7 +1960,7 @@ int dmz_copy_valid_blocks(struct dmz_met
dmz_release_mblock(zmd, to_mblk);
dmz_release_mblock(zmd, from_mblk);

- chunk_block += DMZ_BLOCK_SIZE_BITS;
+ chunk_block += zmd->zone_bits_per_mblk;
}

to_zone->weight = from_zone->weight;
@@ -2017,7 +2021,7 @@ int dmz_validate_blocks(struct dmz_metad

/* Set bits */
bit = chunk_block & DMZ_BLOCK_MASK_BITS;
- nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+ nr_bits = min(nr_blocks, zmd->zone_bits_per_mblk - bit);

count = dmz_set_bits((unsigned long *)mblk->data, bit, nr_bits);
if (count) {
@@ -2096,7 +2100,7 @@ int dmz_invalidate_blocks(struct dmz_met

/* Clear bits */
bit = chunk_block & DMZ_BLOCK_MASK_BITS;
- nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+ nr_bits = min(nr_blocks, zmd->zone_bits_per_mblk - bit);

count = dmz_clear_bits((unsigned long *)mblk->data,
bit, nr_bits);
@@ -2156,6 +2160,7 @@ static int dmz_to_next_set_block(struct
{
struct dmz_mblock *mblk;
unsigned int bit, set_bit, nr_bits;
+ unsigned int zone_bits = zmd->zone_bits_per_mblk;
unsigned long *bitmap;
int n = 0;

@@ -2170,15 +2175,15 @@ static int dmz_to_next_set_block(struct
/* Get offset */
bitmap = (unsigned long *) mblk->data;
bit = chunk_block & DMZ_BLOCK_MASK_BITS;
- nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+ nr_bits = min(nr_blocks, zone_bits - bit);
if (set)
- set_bit = find_next_bit(bitmap, DMZ_BLOCK_SIZE_BITS, bit);
+ set_bit = find_next_bit(bitmap, zone_bits, bit);
else
- set_bit = find_next_zero_bit(bitmap, DMZ_BLOCK_SIZE_BITS, bit);
+ set_bit = find_next_zero_bit(bitmap, zone_bits, bit);
dmz_release_mblock(zmd, mblk);

n += set_bit - bit;
- if (set_bit < DMZ_BLOCK_SIZE_BITS)
+ if (set_bit < zone_bits)
break;

nr_blocks -= nr_bits;
@@ -2281,7 +2286,7 @@ static void dmz_get_zone_weight(struct d
/* Count bits in this block */
bitmap = mblk->data;
bit = chunk_block & DMZ_BLOCK_MASK_BITS;
- nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+ nr_bits = min(nr_blocks, zmd->zone_bits_per_mblk - bit);
n += dmz_count_bits(bitmap, bit, nr_bits);

dmz_release_mblock(zmd, mblk);