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@xxxxxxxxxx>
> ---
> 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.
--D
> +
> +struct xfs_meta_extent {
> + /*
> + * Lowest 54 bits are used to store 512 byte addresses.
> + * Next 2 bits is used for indicating the device.
> + * 00 - Data device
> + * 01 - External log
> + */
> + __be64 xme_addr;
> + /* In units of 512 byte blocks */
> + __be32 xme_len;
> +} __packed;
> +
> +#define XME_ADDR_DEVICE_SHIFT 54
> +
> +#define XME_ADDR_DADDR_MASK ((1ULL << XME_ADDR_DEVICE_SHIFT) - 1)
> +
> +/* Extent was copied from the data device */
> +#define XME_ADDR_DATA_DEVICE (0ULL << XME_ADDR_DEVICE_SHIFT)
> +/* Extent was copied from the log device */
> +#define XME_ADDR_LOG_DEVICE (1ULL << XME_ADDR_DEVICE_SHIFT)
> +
> +#define XME_ADDR_DEVICE_MASK (3ULL << XME_ADDR_DEVICE_SHIFT)
> +
> #endif /* _XFS_METADUMP_H_ */
> --
> 2.39.1
>
