From: Joe Thornber <ejt@xxxxxxxxxx>
Need to check the version to verify on-disk metadata is supported.
Signed-off-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-cache-metadata.c | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 2262b4e..c409c1a 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -20,7 +20,13 @@
#define CACHE_SUPERBLOCK_MAGIC 06142003
#define CACHE_SUPERBLOCK_LOCATION 0
-#define CACHE_VERSION 1
+
+/*
+ * defines a range of metadata versions that this module can handle.
+ */
+#define MIN_CACHE_VERSION 1
+#define MAX_CACHE_VERSION 1
+
#define CACHE_METADATA_CACHE_SIZE 64
/*
@@ -134,6 +140,18 @@ static void sb_prepare_for_write(struct dm_block_validator *v,
SUPERBLOCK_CSUM_XOR));
}
+static int check_metadata_version(struct cache_disk_superblock *disk_super)
+{
+ uint32_t metadata_version = le32_to_cpu(disk_super->version);
+ if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
+ DMERR("kernel does not support this version of cache metadata (%u)",
+ metadata_version);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int sb_check(struct dm_block_validator *v,
struct dm_block *b,
size_t sb_block_size)
@@ -164,7 +182,7 @@ static int sb_check(struct dm_block_validator *v,
return -EILSEQ;
}
- return 0;
+ return check_metadata_version(disk_super);
}
static struct dm_block_validator sb_validator = {
@@ -270,7 +288,7 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
disk_super->flags = 0;
memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
- disk_super->version = cpu_to_le32(CACHE_VERSION);
+ disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
disk_super->policy_hint_size = 0;
--
1.8.1.4
--
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