Commit ad6bf88a authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Jens Axboe
Browse files

block: fix an integer overflow in logical block size

Logical block size has type unsigned short. That means that it can be at
most 32768. However, there are architectures that can run with 64k pages
(for example arm64) and on these architectures, it may be possible to
create block devices with 64k block size.

For exmaple (run this on an architecture with 64k pages):

Mount will fail with this error because it tries to read the superblock using 2-sector
  device-mapper: writecache: I/O is not aligned, sector 2, size 1024, block size 65536
  EXT4-fs (dm-0): unable to read superblock

This patch changes the logical block size from unsigned short to unsigned
int to avoid the overflow.

Reviewed-by: default avatarMartin K. Petersen <>
Reviewed-by: default avatarMing Lei <>
Signed-off-by: default avatarMikulas Patocka <>
Signed-off-by: default avatarJens Axboe <>
parent 16c731fe
......@@ -328,7 +328,7 @@ EXPORT_SYMBOL(blk_queue_max_segment_size);
* storage device can address. The default of 512 covers most
* hardware.
void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
q->limits.logical_block_size = size;
......@@ -17,7 +17,7 @@
#include <linux/dm-bufio.h>
#define DM_MSG_PREFIX "persistent snapshot"
......@@ -87,7 +87,7 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
unsigned short blksize = 512;
unsigned blksize = 512;
*private_conf = ERR_PTR(-ENOMEM);
if (!conf)
......@@ -328,6 +328,7 @@ struct queue_limits {
unsigned int max_sectors;
unsigned int max_segment_size;
unsigned int physical_block_size;
unsigned int logical_block_size;
unsigned int alignment_offset;
unsigned int io_min;
unsigned int io_opt;
......@@ -338,7 +339,6 @@ struct queue_limits {
unsigned int discard_granularity;
unsigned int discard_alignment;
unsigned short logical_block_size;
unsigned short max_segments;
unsigned short max_integrity_segments;
unsigned short max_discard_segments;
......@@ -1077,7 +1077,7 @@ extern void blk_queue_max_write_same_sectors(struct request_queue *q,
unsigned int max_write_same_sectors);
extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
unsigned int max_write_same_sectors);
extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
extern void blk_queue_logical_block_size(struct request_queue *, unsigned int);
extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
extern void blk_queue_alignment_offset(struct request_queue *q,
unsigned int alignment);
......@@ -1291,7 +1291,7 @@ static inline unsigned int queue_max_segment_size(const struct request_queue *q)
return q->limits.max_segment_size;
static inline unsigned short queue_logical_block_size(const struct request_queue *q)
static inline unsigned queue_logical_block_size(const struct request_queue *q)
int retval = 512;
......@@ -1301,7 +1301,7 @@ static inline unsigned short queue_logical_block_size(const struct request_queue
return retval;
static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
static inline unsigned int bdev_logical_block_size(struct block_device *bdev)
return queue_logical_block_size(bdev_get_queue(bdev));
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