Re: [PATCH 12/24] metadump: Define metadump ops for v2 format

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, May 23, 2023 at 02:30:38PM +0530, Chandan Babu R wrote:
> This commit adds functionality to dump metadata from an XFS filesystem in
> newly introduced v2 format.
> 
> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
> ---
>  db/metadump.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 70 insertions(+), 3 deletions(-)
> 
> diff --git a/db/metadump.c b/db/metadump.c
> index 9d7ad76ae..627436e68 100644
> --- a/db/metadump.c
> +++ b/db/metadump.c
> @@ -3037,6 +3037,69 @@ static struct metadump_ops metadump1_ops = {
>  	.release_metadump = release_metadump_v1,
>  };
>  
> +static int
> +init_metadump_v2(void)
> +{
> +	struct xfs_metadump_header xmh = {0};
> +	uint32_t compat_flags = 0;
> +
> +	xmh.xmh_magic = cpu_to_be32(XFS_MD_MAGIC_V2);
> +	xmh.xmh_version = 2;
> +
> +	if (metadump.obfuscate)
> +		compat_flags |= XFS_MD2_INCOMPAT_OBFUSCATED;
> +	if (!metadump.zero_stale_data)
> +		compat_flags |= XFS_MD2_INCOMPAT_FULLBLOCKS;
> +	if (metadump.dirty_log)
> +		compat_flags |= XFS_MD2_INCOMPAT_DIRTYLOG;
> +
> +	xmh.xmh_compat_flags = cpu_to_be32(compat_flags);
> +
> +	if (fwrite(&xmh, sizeof(xmh), 1, metadump.outf) != 1) {
> +		print_warning("error writing to target file");
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +static int
> +write_metadump_v2(
> +	enum typnm	type,
> +	char		*data,
> +	int64_t		off,
> +	int		len)
> +{
> +	struct xfs_meta_extent	xme;
> +	uint64_t		addr;
> +
> +	addr = off;
> +	if (type == TYP_ELOG)
> +		addr |= XME_ADDR_LOG_DEVICE;
> +	else
> +		addr |= XME_ADDR_DATA_DEVICE;
> +
> +	xme.xme_addr = cpu_to_be64(addr);
> +	xme.xme_len = cpu_to_be32(len);
> +
> +	if (fwrite(&xme, sizeof(xme), 1, metadump.outf) != 1) {
> +		print_warning("error writing to target file");
> +		return -EIO;
> +	}
> +
> +	if (fwrite(data, len << BBSHIFT, 1, metadump.outf) != 1) {
> +		print_warning("error writing to target file");
> +		return -EIO;
> +	}

Oh, I see, the v2 format is a straight stream -- first the v2 header,
then a xfs_meta_extent, then the buffer; and repeat #2 and #3 until
finished.  That ought to be documented in the previous patch.

--D

> +
> +	return 0;
> +}
> +
> +static struct metadump_ops metadump2_ops = {
> +	.init_metadump = init_metadump_v2,
> +	.write_metadump = write_metadump_v2,
> +};
> +
>  static int
>  metadump_f(
>  	int 		argc,
> @@ -3178,7 +3241,10 @@ metadump_f(
>  		}
>  	}
>  
> -	metadump.mdops = &metadump1_ops;
> +	if (metadump.version == 1)
> +		metadump.mdops = &metadump1_ops;
> +	else
> +		metadump.mdops = &metadump2_ops;
>  
>  	ret = metadump.mdops->init_metadump();
>  	if (ret)
> @@ -3203,7 +3269,7 @@ metadump_f(
>  		exitcode = !copy_log(log_type);
>  
>  	/* write the remaining index */
> -	if (!exitcode)
> +	if (!exitcode && metadump.mdops->end_write_metadump)
>  		exitcode = metadump.mdops->end_write_metadump() < 0;
>  
>  	if (metadump.progress_since_warning)
> @@ -3223,7 +3289,8 @@ metadump_f(
>  	while (iocur_sp > start_iocur_sp)
>  		pop_cur();
>  
> -	metadump.mdops->release_metadump();
> +	if (metadump.mdops->release_metadump)
> +		metadump.mdops->release_metadump();
>  
>  out:
>  	return 0;
> -- 
> 2.39.1
>