Commit 32e67a3a authored by Josef Bacik's avatar Josef Bacik Committed by Jens Axboe
Browse files

nbd: handle interrupted sendmsg with a sndtimeo set 



If you do not set sk_sndtimeo you will get -ERESTARTSYS if there is a
pending signal when you enter sendmsg, which we handle properly.
However if you set a timeout for your commands we'll set sk_sndtimeo to
that timeout, which means that sendmsg will start returning -EINTR
instead of -ERESTARTSYS.  Fix this by checking either cases and doing
the correct thing.

Cc: stable@vger.kernel.org
Fixes: dc88e34d ("nbd: set sk->sk_sndtimeo for our sockets")
Reported-and-tested-by: default avatarDaniel Xu <dlxu@fb.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 87539746

drivers/block/nbd.c

+11 −2
Original line number Diff line number Diff line
@@ -386,6 +386,15 @@ static int sock_xmit(struct nbd_device *nbd, int index, int send, 
	return result;

}



/*

 * Different settings for sk->sk_sndtimeo can result in different return values

 * if there is a signal pending when we enter sendmsg, because reasons?

 */

static inline int was_interrupted(int result)

{

	return result == -ERESTARTSYS || result == -EINTR;

}



/* always call with the tx_lock held */

static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)

{
@@ -458,7 +467,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) 
	result = sock_xmit(nbd, index, 1, &from,

			(type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);

	if (result <= 0) {

		if (result == -ERESTARTSYS) {

		if (was_interrupted(result)) {

			/* If we havne't sent anything we can just return BUSY,

			 * however if we have sent something we need to make

			 * sure we only allow this req to be sent until we are
@@ -502,7 +511,7 @@ send_pages: 
			}

			result = sock_xmit(nbd, index, 1, &from, flags, &sent);

			if (result <= 0) {

				if (result == -ERESTARTSYS) {

				if (was_interrupted(result)) {

					/* We've already sent the header, we

					 * have no choice but to set pending and

					 * return BUSY.

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