From 214bf0a21363d5d00a2bdd27aa2a3551c106ccb7 Mon Sep 17 00:00:00 2001 From: Chandan Babu R Date: Mon, 6 Nov 2023 18:40:48 +0530 Subject: [PATCH] mdrestore: Detect metadump v1 magic before reading the header 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. Reviewed-by: "Darrick J. Wong" Signed-off-by: Chandan Babu R Signed-off-by: Carlos Maiolino --- mdrestore/xfs_mdrestore.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c index 97cb4e35c..ffa8274f3 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 +246,21 @@ 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) { -- 2.39.5