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nbd: clear DISCONNECT_REQUESTED flag once disconnection occurs.

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When a userspace client requests a NBD device be disconnected, the
DISCONNECT_REQUESTED flag is set. While this flag is set, the driver
will not inform userspace when a connection is closed.

Unfortunately the flag was never cleared, so once a disconnect was
requested the driver would thereafter never tell userspace about a
closed connection. Thus when connections failed due to timeout, no
attempt to reconnect was made and eventually the device would fail.

Fix by clearing the DISCONNECT_REQUESTED flag (and setting the
DISCONNECTED flag) once all connections are closed.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Kevin Vigor <kvigor@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Kevin Vigor 2018-05-30 10:45:11 -06:00 committed by Jens Axboe
parent 2ab74cd296
commit 5e3c3a7ece
1 changed files with 15 additions and 6 deletions
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21
drivers/block/nbd.c
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@ -216,7 +216,15 @@ static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
}
if (!nsock->dead) {
kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
atomic_dec(&nbd->config->live_connections);
if (atomic_dec_return(&nbd->config->live_connections) == 0) {
if (test_and_clear_bit(NBD_DISCONNECT_REQUESTED,
&nbd->config->runtime_flags)) {
set_bit(NBD_DISCONNECTED,
&nbd->config->runtime_flags);
dev_info(nbd_to_dev(nbd),
"Disconnected due to user request.\n");
}
}
}
nsock->dead = true;
nsock->pending = NULL;
@ -310,7 +318,9 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
if (config->num_connections > 1) {
dev_err_ratelimited(nbd_to_dev(nbd),
"Connection timed out, retrying\n");
"Connection timed out, retrying (%d/%d alive)\n",
atomic_read(&config->live_connections),
config->num_connections);
/*
* Hooray we have more connections, requeue this IO, the submit
* path will put it on a real connection.
@ -733,10 +743,9 @@ static int wait_for_reconnect(struct nbd_device *nbd)
return 0;
if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
return 0;
wait_event_timeout(config->conn_wait,
atomic_read(&config->live_connections),
config->dead_conn_timeout);
return atomic_read(&config->live_connections);
return wait_event_timeout(config->conn_wait,
atomic_read(&config->live_connections) > 0,
config->dead_conn_timeout) > 0;
}
static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)