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 access: 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.

Mikulas Patocka committed 6 years ago

Commit ad6bf881 parent 16c731f4 files · +7 −7Browse files

Unified · Split

4 files

block/blk-settings.c +1 −1
drivers/md/dm-snap-persistent.c +1 −1
drivers/md/raid0.c +1 −1
include/linux/blkdev.h +4 −4

block/blk-settings.c+1−1

@@ -328,7 +328,7 @@ EXPORT_SYMBOL(blk_queue_max_segment_size); · 327 unmodified lines
328	328	* storage device can address. The default of 512 covers most
329	329	* hardware.
330	330	**/
331		−void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
	331	+void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
332	332	{
333	333	q->limits.logical_block_size = size;
334	334

drivers/md/dm-snap-persistent.c+1−1

@@ -17,7 +17,7 @@ · 16 unmodified lines
17	17	#include <linux/dm-bufio.h>
18	18
19	19	#define DM_MSG_PREFIX "persistent snapshot"
20		−#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */
	20	+#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32U /* 16KB */
21	21
22	22	#define DM_PREFETCH_CHUNKS 12
23	23

drivers/md/raid0.c+1−1

@@ -87,7 +87,7 @@ static int create_strip_zones(struct mddev mddev, struct r0conf *private_conf) · 86 unmodified lines
87	87	char b[BDEVNAME_SIZE];
88	88	char b2[BDEVNAME_SIZE];
89	89	struct r0conf conf = kzalloc(sizeof(conf), GFP_KERNEL);
90		− unsigned short blksize = 512;
	90	+ unsigned blksize = 512;
91	91
92	92	*private_conf = ERR_PTR(-ENOMEM);
93	93	if (!conf)

include/linux/blkdev.h+4−4

@@ -328,6 +328,7 @@ struct queue_limits { · 327 unmodified lines
328	328	unsigned int max_sectors;
329	329	unsigned int max_segment_size;
330	330	unsigned int physical_block_size;
	331	+ unsigned int logical_block_size;
331	332	unsigned int alignment_offset;
332	333	unsigned int io_min;
333	334	unsigned int io_opt;
@@ -338,7 +339,6 @@ struct queue_limits { · 4 unmodified lines
338	339	unsigned int discard_granularity;
339	340	unsigned int discard_alignment;
340	341
341		− unsigned short logical_block_size;
342	342	unsigned short max_segments;
343	343	unsigned short max_integrity_segments;
344	344	unsigned short max_discard_segments;
@@ -1077,7 +1077,7 @@ extern void blk_queue_max_write_same_sectors(struct request_queue *q, · 732 unmodified lines
1077	1077	unsigned int max_write_same_sectors);
1078	1078	extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
1079	1079	unsigned int max_write_same_sectors);
1080		−extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
	1080	+extern void blk_queue_logical_block_size(struct request_queue *, unsigned int);
1081	1081	extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
1082	1082	extern void blk_queue_alignment_offset(struct request_queue *q,
1083	1083	unsigned int alignment);
@@ -1291,7 +1291,7 @@ static inline unsigned int queue_max_segment_size(const struct request_queue *q) · 207 unmodified lines
1291	1291	return q->limits.max_segment_size;
1292	1292	}
1293	1293
1294		−static inline unsigned short queue_logical_block_size(const struct request_queue *q)
	1294	+static inline unsigned queue_logical_block_size(const struct request_queue *q)
1295	1295	{
1296	1296	int retval = 512;
1297	1297
@@ -1301,7 +1301,7 @@ static inline unsigned short queue_logical_block_size(const struct request_queue · 3 unmodified lines
1301	1301	return retval;
1302	1302	}
1303	1303
1304		−static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
	1304	+static inline unsigned int bdev_logical_block_size(struct block_device *bdev)
1305	1305	{
1306	1306	return queue_logical_block_size(bdev_get_queue(bdev));
1307	1307	}