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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: dc88e34d69 ("nbd: set sk->sk_sndtimeo for our sockets")
Reported-and-tested-by: Daniel Xu <dlxu@fb.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Josef Bacik 2017-10-24 15:57:18 -04:00 committed by Jens Axboe
parent 875397464a
commit 32e67a3a06
1 changed files with 11 additions and 2 deletions
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13
drivers/block/nbd.c
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@ -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 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
}
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.