btrfs-progs: check: Skip data csum verification for metadata dump

For metadata dump (fs restored by btrfs-image), no data is restored
and check sum verification will definitely report error.

Add such check in check_csums() and prompt for user input.

Issue: #103
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/check/main.c b/check/main.c
index 891a6d7..15c9454 100644 (file)
--- a/check/main.c
+++ b/check/main.c
@@ -5601,6 +5601,7 @@ static int check_csums(struct btrfs_root *root)
        int ret;
        u64 data_len;
        unsigned long leaf_offset;
+       bool verify_csum = !!check_data_csum;
 
        root = root->fs_info->csum_root;
        if (!extent_buffer_uptodate(root->node)) {
@@ -5623,6 +5624,16 @@ static int check_csums(struct btrfs_root *root)
                path.slots[0]--;
        ret = 0;
 
+       /*
+        * For metadata dump (btrfs-image) all data is wiped so verifying data
+        * csum is meaningless and will always report csum error.
+        */
+       if (check_data_csum && (btrfs_super_flags(root->fs_info->super_copy) &
+           (BTRFS_SUPER_FLAG_METADUMP | BTRFS_SUPER_FLAG_METADUMP_V2))) {
+               printf("skip data csum verification for metadata dump\n");
+               verify_csum = false;
+       }
+
        while (1) {
                if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
                        ret = btrfs_next_leaf(root, &path);
@@ -5644,7 +5655,7 @@ static int check_csums(struct btrfs_root *root)
 
                data_len = (btrfs_item_size_nr(leaf, path.slots[0]) /
                              csum_size) * root->fs_info->sectorsize;
-               if (!check_data_csum)
+               if (!verify_csum)
                        goto skip_csum_check;
                leaf_offset = btrfs_item_ptr_offset(leaf, path.slots[0]);
                ret = check_extent_csums(root, key.offset, data_len,