diff options
| -rw-r--r-- | Documentation/device-mapper/cache.txt | 3 | ||||
| -rw-r--r-- | drivers/md/dm-cache-target.c | 17 |
2 files changed, 12 insertions, 8 deletions
diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt index af99c458c841..33d45ee0b737 100644 --- a/Documentation/device-mapper/cache.txt +++ b/Documentation/device-mapper/cache.txt @@ -58,7 +58,8 @@ Fixed block size The origin is divided up into blocks of a fixed size. This block size is configurable when you first create the cache. Typically we've been -using block sizes of 256k - 1024k. +using block sizes of 256KB - 1024KB. The block size must be between 64 +(32KB) and 2097152 (1GB) and a multiple of 64 (32KB). Having a fixed block size simplifies the target a lot. But it is something of a compromise. For instance, a small part of a block may be diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 0df3ec085ebb..31985ea81408 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -67,9 +67,11 @@ static void free_bitset(unsigned long *bits) #define MIGRATION_COUNT_WINDOW 10 /* - * The block size of the device holding cache data must be >= 32KB + * The block size of the device holding cache data must be + * between 32KB and 1GB. */ #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) +#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) /* * FIXME: the cache is read/write for the time being. @@ -1687,24 +1689,25 @@ static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, char **error) { - unsigned long tmp; + unsigned long block_size; if (!at_least_one_arg(as, error)) return -EINVAL; - if (kstrtoul(dm_shift_arg(as), 10, &tmp) || !tmp || - tmp < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || - tmp & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { + if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size || + block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || + block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || + block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { *error = "Invalid data block size"; return -EINVAL; } - if (tmp > ca->cache_sectors) { + if (block_size > ca->cache_sectors) { *error = "Data block size is larger than the cache device"; return -EINVAL; } - ca->block_size = tmp; + ca->block_size = block_size; return 0; } |