Btrfs: use received_uuid of parent during send (37b8d27d) · Commits · 戴 / test

Neil Horman pointed out a problem where if he did something like this receive A snap A B change B send -p A B and then on another box do recieve A receive B the receive B would fail because we use the UUID of A for the clone sources for B. This makes sense most of the time because normally you are sending from the original sources, not a received source. However when you use a recieved subvol its UUID is going to be something completely different, so if you then try to receive the diff on a different volume it won't find the UUID because the new A will be something else. The only constant is the received uuid. So instead check to see if we have received_uuid set on the root, and if so use that as the clone source, as btrfs receive looks for matches either in received_uuid or uuid. Thanks, Reported-by:

Neil Horman <nhorman@redhat.com> Signed-off-by:

Josef Bacik <jbacik@fb.com> Reviewed-by:

Hugo Mills <hugo@carfax.org.uk> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/send.c

+21 −4

Original line number	Diff line number	Diff line
		@@ -2356,8 +2356,12 @@ static int send_subvol_begin(struct send_ctx *sctx)
		TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
		le64_to_cpu(sctx->send_root->root_item.ctransid));
		if (parent_root) {
		if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid))
		TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
		sctx->parent_root->root_item.uuid);
		parent_root->root_item.received_uuid);
		else
		TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
		parent_root->root_item.uuid);
		TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
		le64_to_cpu(sctx->parent_root->root_item.ctransid));
		}
		@@ -4586,6 +4590,19 @@ verbose_printk("btrfs: send_clone offset=%llu, len=%d, clone_root=%llu, "
		if (ret < 0)
		goto out;

		/*
		* If the parent we're using has a received_uuid set then use that as
		* our clone source as that is what we will look for when doing a
		* receive.
		*
		* This covers the case that we create a snapshot off of a received
		* subvolume and then use that as the parent and try to receive on a
		* different host.
		*/
		if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid))
		TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
		clone_root->root->root_item.received_uuid);
		else
		TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
		clone_root->root->root_item.uuid);
		TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,

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