Re: [PATCH V2 10/23] metadump: Define metadump v2 ondisk format structures and macros

[Chandan Babu R <chandan.babu@oracle.com>]

On Wed, Jul 12, 2023 at 10:18:42 AM -0700, Darrick J. Wong wrote:
> On Tue, Jun 06, 2023 at 02:57:53PM +0530, Chandan Babu R wrote:
>> The corresponding metadump file's disk layout is as shown below,
>> 
>>      |------------------------------|
>>      | struct xfs_metadump_header   |
>>      |------------------------------|
>>      | struct xfs_meta_extent 0     |
>>      | Extent 0's data              |
>>      | struct xfs_meta_extent 1     |
>>      | Extent 1's data              |
>>      | ...                          |
>>      | struct xfs_meta_extent (n-1) |
>>      | Extent (n-1)'s data          |
>>      |------------------------------|
>> 
>> The "struct xfs_metadump_header" is followed by alternating series of "struct
>> xfs_meta_extent" and the extent itself.
>> 
>> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
>> ---
>>  include/xfs_metadump.h | 58 ++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 58 insertions(+)
>> 
>> diff --git a/include/xfs_metadump.h b/include/xfs_metadump.h
>> index a4dca25c..518cb302 100644
>> --- a/include/xfs_metadump.h
>> +++ b/include/xfs_metadump.h
>> @@ -8,7 +8,9 @@
>>  #define _XFS_METADUMP_H_
>>  
>>  #define	XFS_MD_MAGIC_V1		0x5846534d	/* 'XFSM' */
>> +#define	XFS_MD_MAGIC_V2		0x584D4432	/* 'XMD2' */
>>  
>> +/* Metadump v1 */
>>  typedef struct xfs_metablock {
>>  	__be32		mb_magic;
>>  	__be16		mb_count;
>> @@ -23,4 +25,60 @@ typedef struct xfs_metablock {
>>  #define XFS_METADUMP_FULLBLOCKS	(1 << 2)
>>  #define XFS_METADUMP_DIRTYLOG	(1 << 3)
>>  
>> +/*
>> + * Metadump v2
>> + *
>> + * The following diagram depicts the ondisk layout of the metadump v2 format.
>> + *
>> + * |------------------------------|
>> + * | struct xfs_metadump_header   |
>> + * |------------------------------|
>> + * | struct xfs_meta_extent 0     |
>> + * | Extent 0's data              |
>> + * | struct xfs_meta_extent 1     |
>> + * | Extent 1's data              |
>> + * | ...                          |
>> + * | struct xfs_meta_extent (n-1) |
>> + * | Extent (n-1)'s data          |
>> + * |------------------------------|
>> + *
>> + * The "struct xfs_metadump_header" is followed by alternating series of "struct
>> + * xfs_meta_extent" and the extent itself.
>> + */
>> +struct xfs_metadump_header {
>> +	__be32		xmh_magic;
>> +	__be32		xmh_version;
>> +	__be32		xmh_compat_flags;
>> +	__be32		xmh_incompat_flags;
>> +	__be64		xmh_reserved;
>> +} __packed;
>> +
>> +#define XFS_MD2_INCOMPAT_OBFUSCATED	(1 << 0)
>> +#define XFS_MD2_INCOMPAT_FULLBLOCKS	(1 << 1)
>> +#define XFS_MD2_INCOMPAT_DIRTYLOG	(1 << 2)
>> +#define XFS_MD2_INCOMPAT_EXTERNALLOG	(1 << 3)
>
> Please document the meaning of these four flags.
>
> /*
>  * User-supplied directory entry and extended attribute names have been
>  * obscured, and extended attribute values are zeroed to protect privacy.
>  */
> #define XFS_MD2_INCOMPAT_OBFUSCATED	(1 << 0)
>
> /* Full blocks have been dumped. */
> #define XFS_MD2_INCOMPAT_FULLBLOCKS	(1 << 1)
>
> /* Log was dirty. */
> #define XFS_MD2_INCOMPAT_DIRTYLOG	(1 << 2)
>
> /* Dump contains external log contents. */
> #define XFS_MD2_INCOMPAT_EXTERNALLOG	(1 << 3)
>
> Otherwise looks fine to me.
>

Sure. I will add the required comments.

-- 
chandan