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Date:   Fri, 11 Sep 2020 16:13:39 +0200
From:   David Sterba <dsterba@suse.cz>
To:     Omar Sandoval <osandov@osandov.com>
Cc:     linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/9] btrfs: send: avoid copying file data
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On Fri, Aug 21, 2020 at 12:39:52AM -0700, Omar Sandoval wrote:
> +static int put_data_header(struct send_ctx *sctx, u32 len)
> +{
> +	struct btrfs_tlv_header *hdr;
> +
> +	if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len)
> +		return -EOVERFLOW;
> +	hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size);
> +	hdr->tlv_type = cpu_to_le16(BTRFS_SEND_A_DATA);
> +	hdr->tlv_len = cpu_to_le16(len);

I think we need put_unaligned_le16 here, it's mapping a random buffer to
a pointer, this is not alignment safe in general.