[PATCH v2 02/17] bcache: add read_super_basic() to read major part of super block

Coly Li
2020-07-15T05:46:25Z

Later patches will introduce feature set bits to on-disk super block and
increase super block version. Current code in read_super() which reads
basic part of super block for version BCACHE_SB_VERSION_CDEV and version
BCACHE_SB_VERSION_CDEV_WITH_UUID will be shared with the new version.

Therefore this patch moves the reusable part into read_super_basic(),
this preparation patch will make later patches more simplier and only
focus on new feature set bits.

Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/bcache/super.c | 111 +++++++++++++++++++++-----------------
1 file changed, 63 insertions(+), 48 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 7aa1d6737f66..74681fb92158 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -59,6 +59,67 @@ struct workqueue_struct *bch_journal_wq;

/* Superblock */

+static const char *read_super_basic(struct cache_sb *sb, struct block_device *bdev,
+ struct cache_sb_disk *s)
+{
+ const char *err;
+ unsigned int i;
+
+ sb->nbuckets = le64_to_cpu(s->nbuckets);
+ 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);
+
+ 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;
+
+ err = NULL;
+err:
+ return err;
+}
+
+
static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
struct cache_sb_disk **res)
{
@@ -133,55 +194,9 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
break;
case BCACHE_SB_VERSION_CDEV:
case BCACHE_SB_VERSION_CDEV_WITH_UUID:
- sb->nbuckets = le64_to_cpu(s->nbuckets);
- 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);
-
- 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)
+ err = read_super_basic(sb, bdev, s);
+ if (err)
goto err;
-
break;
default:
err = "Unsupported superblock version";
--
2.26.2