David Howells <dhowells@xxxxxxxxxx> wrote:
> I am seeing the occasional:
>
> CIFS: trying to dequeue a deleted mid
>
> but I haven't managed to work out how I get to that yet.
That turned out to be due to EFAULT occurring in sock_recvmsg() called from
cifs_readv_from_socket() because it was handed an iovec-class iov_iter. It
went through:
if (length <= 0) {
cifs_dbg(FYI, "Received no data or error: %d\n", length);
cifs_reconnect(server, false);
return -ECONNABORTED;
}
which called cifs_abort_connection() which forcibly marked the MIDs as
deleted. However, they got dequeued later which triggered the message.
Telling netfs's DIO read to turn it into a bvec-class iov_iter instead stopped
that happening, but it's may be a latent problem.
I also found the causes of the occasional "server overflowed SMB3 credits"
messages that I've been seeing:
Firstly, the data read path was returning credits both when freeing the
subrequest and at the end of smb2_readv_callback(). I made the former
conditional on not doing the latter.
Secondly, cifs_write_back_from_locked_page() was returning credits, even if
->async_writev() was successful. I made that only do it on error.
And now it gets through generic/013 for me.
David
