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@xxxxxxxxxx>
Signed-off-by: Josef Bacik <jbacik@xxxxxx>
---
fs/btrfs/send.c | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index a1216f9..947d91c 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -2328,8 +2328,12 @@ 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) {
- TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
- sctx->parent_root->root_item.uuid);
+ if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid))
+ TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_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));
}
@@ -4508,8 +4512,21 @@ verbose_printk("btrfs: send_clone offset=%llu, len=%d, clone_root=%llu, "
if (ret < 0)
goto out;
- TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
- clone_root->root->root_item.uuid);
+ /*
+ * 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,
le64_to_cpu(clone_root->root->root_item.ctransid));
TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p);
--
1.8.3.1
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