On Tue, Jun 06, 2023 at 02:57:59PM +0530, Chandan Babu R wrote:
> In order to support both v1 and v2 versions of metadump, mdrestore will have
> to detect the format in which the metadump file has been stored on the disk
> and then read the ondisk structures accordingly. In a step in that direction,
> this commit splits the work of reading the metadump header from disk into two
> parts
> 1. Read the first 4 bytes containing the metadump magic code.
> 2. Read the remaining part of the header.
>
> A future commit will take appropriate action based on the value of the magic
> code.
>
> Signed-off-by: Chandan Babu R <chandan.babu@xxxxxxxxxx>
Seems reasonable to me,
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> mdrestore/xfs_mdrestore.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
> index 564630f7..2a9527b9 100644
> --- a/mdrestore/xfs_mdrestore.c
> +++ b/mdrestore/xfs_mdrestore.c
> @@ -198,6 +198,7 @@ main(
> int open_flags;
> struct stat statbuf;
> int is_target_file;
> + uint32_t magic;
> struct xfs_metablock mb;
>
> mdrestore.show_progress = false;
> @@ -245,10 +246,20 @@ main(
> fatal("cannot open source dump file\n");
> }
>
> - if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> - fatal("error reading from metadump file\n");
> - if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC_V1))
> + if (fread(&magic, sizeof(magic), 1, src_f) != 1)
> + fatal("Unable to read metadump magic from metadump file\n");
> +
> + switch (be32_to_cpu(magic)) {
> + case XFS_MD_MAGIC_V1:
> + mb.mb_magic = cpu_to_be32(XFS_MD_MAGIC_V1);
> + if (fread((uint8_t *)&mb + sizeof(mb.mb_magic),
> + sizeof(mb) - sizeof(mb.mb_magic), 1, src_f) != 1)
> + fatal("error reading from metadump file\n");
> + break;
> + default:
> fatal("specified file is not a metadata dump\n");
> + break;
> + }
>
> if (mdrestore.show_info) {
> if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
> --
> 2.39.1
>
