On 2020/7/15 14:02, Hannes Reinecke wrote:
> On 7/15/20 7:45 AM, Coly Li wrote:
>> This patch adds comments to mark each member of struct cache_sb_disk,
>> it is helpful to understand the bcache superblock on-disk layout.
>>
>> Signed-off-by: Coly Li <colyli@xxxxxxx>
>> ---
>> include/uapi/linux/bcache.h | 39 +++++++++++++++++++------------------
>> 1 file changed, 20 insertions(+), 19 deletions(-)
>>
>> diff --git a/include/uapi/linux/bcache.h b/include/uapi/linux/bcache.h
>> index 9a1965c6c3d0..afbd1b56a661 100644
>> --- a/include/uapi/linux/bcache.h
>> +++ b/include/uapi/linux/bcache.h
>> @@ -158,33 +158,33 @@ static inline struct bkey *bkey_idx(const struct
>> bkey *k, unsigned int nr_keys)
>> #define BDEV_DATA_START_DEFAULT 16 /* sectors */
>> struct cache_sb_disk {
>> - __le64 csum;
>> - __le64 offset; /* sector where this sb was written */
>> - __le64 version;
>> +/*000*/ __le64 csum;
>> +/*008*/ __le64 offset; /* sector where this sb was
>> written */
>> +/*010*/ __le64 version;
>> - __u8 magic[16];
>> +/*018*/ __u8 magic[16];
>> - __u8 uuid[16];
>> +/*028*/ __u8 uuid[16];
>> union {
>> - __u8 set_uuid[16];
>> +/*038*/ __u8 set_uuid[16];
>> __le64 set_magic;
>> };
>> - __u8 label[SB_LABEL_SIZE];
>> +/*048*/ __u8 label[SB_LABEL_SIZE];
>> - __le64 flags;
>> - __le64 seq;
>> - __le64 pad[8];
>> +/*068*/ __le64 flags;
>> +/*070*/ __le64 seq;
>> +/*078*/ __le64 pad[8];
>> union {
>> struct {
>> /* Cache devices */
>> - __le64 nbuckets; /* device size */
>> +/*0b8*/ __le64 nbuckets; /* device size */
>> - __le16 block_size; /* sectors */
>> - __le16 bucket_size; /* sectors */
>> +/*0c0*/ __le16 block_size; /* sectors */
>> +/*0c2*/ __le16 bucket_size; /* sectors */
>> - __le16 nr_in_set;
>> - __le16 nr_this_dev;
>> +/*0c4*/ __le16 nr_in_set;
>> +/*0c6*/ __le16 nr_this_dev;
>> };
>> struct {
>> /* Backing devices */
>> @@ -198,14 +198,15 @@ struct cache_sb_disk {
>> };
>> };
>> - __le32 last_mount; /* time overflow in y2106 */
>> +/*0c8*/ __le32 last_mount; /* time overflow in y2106 */
>> - __le16 first_bucket;
>> +/*0cc*/ __le16 first_bucket;
>> union {
>> - __le16 njournal_buckets;
>> +/*0ce*/ __le16 njournal_buckets;
>> __le16 keys;
>> };
>> - __le64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
>> +/*0d0*/ __le64 d[SB_JOURNAL_BUCKETS]; /* journal
>> buckets */
>> +/*8d0*/
>> };
>> struct cache_sb {
>>
> Common practice is to place comments at the end; please don't use the
> start of the line here.
Hi Hannes,
When I try to move the offset comment to the line end, I find it
conflicts with normal code comment, e.g.
__le64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
I have to add the offset comment to the line start. I guess this is why
ocfs2 code adds the offset comment at the line start.
So finally I have to keep the offset comment on line start still...
Coly Li
