bcache: Take data offset from the bdev superblock.
Add a new superblock version, and consolidate related defines.
Signed-off-by: Gabriel de Perthuis <g2p.code+bcache@gmail.com>
Signed-off-by: Kent Overstreet <koverstreet@google.com>
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 5fa3cd2..f1e69f2 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -110,15 +110,7 @@
sb->flags = le64_to_cpu(s->flags);
sb->seq = le64_to_cpu(s->seq);
-
- sb->nbuckets = le64_to_cpu(s->nbuckets);
- sb->block_size = le16_to_cpu(s->block_size);
- sb->bucket_size = le16_to_cpu(s->bucket_size);
-
- sb->nr_in_set = le16_to_cpu(s->nr_in_set);
- sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
sb->last_mount = le32_to_cpu(s->last_mount);
-
sb->first_bucket = le16_to_cpu(s->first_bucket);
sb->keys = le16_to_cpu(s->keys);
@@ -147,53 +139,77 @@
if (bch_is_zero(sb->uuid, 16))
goto err;
- err = "Unsupported superblock version";
- if (sb->version > BCACHE_SB_VERSION)
- goto err;
+ switch (sb->version) {
+ case BCACHE_SB_VERSION_BDEV:
+ sb->block_size = le16_to_cpu(s->block_size);
+ sb->data_offset = BDEV_DATA_START_DEFAULT;
+ break;
+ case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
+ sb->block_size = le16_to_cpu(s->block_size);
+ sb->data_offset = le64_to_cpu(s->data_offset);
- err = "Bad block/bucket size";
- if (!is_power_of_2(sb->block_size) || sb->block_size > PAGE_SECTORS ||
- !is_power_of_2(sb->bucket_size) || sb->bucket_size < PAGE_SECTORS)
- goto err;
-
- err = "Too many buckets";
- if (sb->nbuckets > LONG_MAX)
- goto err;
-
- err = "Not enough buckets";
- if (sb->nbuckets < 1 << 7)
- goto err;
-
- err = "Invalid superblock: device too small";
- if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets)
- goto err;
-
- if (sb->version == CACHE_BACKING_DEV)
- goto out;
-
- err = "Bad UUID";
- if (bch_is_zero(sb->set_uuid, 16))
- goto err;
-
- err = "Bad cache device number in set";
- if (!sb->nr_in_set ||
- sb->nr_in_set <= sb->nr_this_dev ||
- sb->nr_in_set > MAX_CACHES_PER_SET)
- goto err;
-
- err = "Journal buckets not sequential";
- for (i = 0; i < sb->keys; i++)
- if (sb->d[i] != sb->first_bucket + i)
+ err = "Bad data offset";
+ if (sb->data_offset < BDEV_DATA_START_DEFAULT)
goto err;
- err = "Too many journal buckets";
- if (sb->first_bucket + sb->keys > sb->nbuckets)
- goto err;
+ break;
+ case BCACHE_SB_VERSION_CDEV:
+ case BCACHE_SB_VERSION_CDEV_WITH_UUID:
+ sb->nbuckets = le64_to_cpu(s->nbuckets);
+ sb->block_size = le16_to_cpu(s->block_size);
+ sb->bucket_size = le16_to_cpu(s->bucket_size);
- err = "Invalid superblock: first bucket comes before end of super";
- if (sb->first_bucket * sb->bucket_size < 16)
+ sb->nr_in_set = le16_to_cpu(s->nr_in_set);
+ sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
+
+ err = "Too many buckets";
+ if (sb->nbuckets > LONG_MAX)
+ goto err;
+
+ err = "Not enough buckets";
+ if (sb->nbuckets < 1 << 7)
+ goto err;
+
+ err = "Bad block/bucket size";
+ if (!is_power_of_2(sb->block_size) ||
+ sb->block_size > PAGE_SECTORS ||
+ !is_power_of_2(sb->bucket_size) ||
+ sb->bucket_size < PAGE_SECTORS)
+ goto err;
+
+ err = "Invalid superblock: device too small";
+ if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets)
+ goto err;
+
+ err = "Bad UUID";
+ if (bch_is_zero(sb->set_uuid, 16))
+ goto err;
+
+ err = "Bad cache device number in set";
+ if (!sb->nr_in_set ||
+ sb->nr_in_set <= sb->nr_this_dev ||
+ sb->nr_in_set > MAX_CACHES_PER_SET)
+ goto err;
+
+ err = "Journal buckets not sequential";
+ for (i = 0; i < sb->keys; i++)
+ if (sb->d[i] != sb->first_bucket + i)
+ goto err;
+
+ err = "Too many journal buckets";
+ if (sb->first_bucket + sb->keys > sb->nbuckets)
+ goto err;
+
+ err = "Invalid superblock: first bucket comes before end of super";
+ if (sb->first_bucket * sb->bucket_size < 16)
+ goto err;
+
+ break;
+ default:
+ err = "Unsupported superblock version";
goto err;
-out:
+ }
+
sb->last_mount = get_seconds();
err = NULL;
@@ -286,7 +302,7 @@
for_each_cache(ca, c, i) {
struct bio *bio = &ca->sb_bio;
- ca->sb.version = BCACHE_SB_VERSION;
+ ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
ca->sb.seq = c->sb.seq;
ca->sb.last_mount = c->sb.last_mount;
@@ -1049,7 +1065,7 @@
g = dc->disk.disk;
- set_capacity(g, dc->bdev->bd_part->nr_sects - 16);
+ set_capacity(g, dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
bch_cached_dev_request_init(dc);
@@ -1802,7 +1818,7 @@
if (err)
goto err_close;
- if (sb->version == CACHE_BACKING_DEV) {
+ if (SB_IS_BDEV(sb)) {
struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
err = register_bdev(sb, sb_page, bdev, dc);