On Sat, Oct 26, 2019 at 06:11:27PM +0800, Qu Wenruo wrote:
> + /*
> + * Log tree only exists in the primary super block, so SBREAD_DEFAULT
> + * is enough.
For read it should be enough to read the default one, but do you mean
that 1st and 2nd copy don't have the log_root values set? They're
written from the same buffer so I'd expect the contents to be the same.
> + ret = btrfs_read_dev_super(fd, sb, BTRFS_SUPER_INFO_OFFSET,
> + SBREAD_DEFAULT);
> + if (ret < 0) {
> + errno = -ret;
> + error("failed to read super block on '%s': %m", devname);
> + goto close_fd;
> }
>
> - sb = root->fs_info->super_copy;
> printf("Clearing log on %s, previous log_root %llu, level %u\n",
> devname,
> (unsigned long long)btrfs_super_log_root(sb),
> (unsigned)btrfs_super_log_root_level(sb));
> - trans = btrfs_start_transaction(root, 1);
> - BUG_ON(IS_ERR(trans));
> btrfs_set_super_log_root(sb, 0);
> btrfs_set_super_log_root_level(sb, 0);
> - btrfs_commit_transaction(trans, root);
> - close_ctree(root);
> + btrfs_csum_data(btrfs_super_csum_type(sb), (u8 *)sb + BTRFS_CSUM_SIZE,
> + result, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
> + memcpy(&sb->csum[0], result, BTRFS_CSUM_SIZE);
> + ret = pwrite64(fd, sb, BTRFS_SUPER_INFO_SIZE, BTRFS_SUPER_INFO_OFFSET);
So this only writes on the one device that's passed to the command.
Previously it would update superblocks on all devices.
