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 <[email protected]> Signed-off-by: Josef Bacik <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
