Commit b28f582c authored by Max Reitz's avatar Max Reitz Committed by Eric Blake
Browse files

iotests: Let 233 run concurrently 



common.nbd's nbd_server_set_tcp_port() tries to find a free port, and
then uses it for the whole test run.  However, this is racy because even
if the port was free at the beginning, there is no guarantee it will
continue to be available.  Therefore, 233 currently cannot reliably be
run concurrently with other NBD TCP tests.

This patch addresses the problem by dropping nbd_server_set_tcp_port(),
and instead finding a new port every time nbd_server_start_tcp_socket()
is invoked.  For this, we run qemu-nbd with --fork and on error evaluate
the output to see whether it contains "Address already in use".  If so,
we try the next port.

On success, we still want to continually redirect the output from
qemu-nbd to stderr.  To achieve both, we redirect qemu-nbd's stderr to a
FIFO that we then open in bash.  If the parent process exits with status
0 (which means that the server has started successfully), we launch a
background cat process that copies the FIFO to stderr.  On failure, we
read the whole content into a variable and then evaluate it.

While at it, use --fork in nbd_server_start_unix_socket(), too.  Doing
so allows us to drop nbd_server_wait_for_*_socket().

Note that the reason common.nbd did not use --fork before is that
qemu-nbd did not have --pid-file.

Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20190508211820.17851-6-mreitz@redhat.com>
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent 4718360a

tests/qemu-iotests/233

+0 −1
Original line number Diff line number Diff line
@@ -49,7 +49,6 @@ _supported_proto file 
# If porting to non-Linux, consider using socat instead of ss in common.nbd

_require_command QEMU_NBD



nbd_server_set_tcp_port

tls_x509_init



echo

tests/qemu-iotests/common.nbd

+42 −52
Original line number Diff line number Diff line
@@ -22,6 +22,11 @@ 
nbd_unix_socket="${TEST_DIR}/qemu-nbd.sock"

nbd_tcp_addr="127.0.0.1"

nbd_pid_file="${TEST_DIR}/qemu-nbd.pid"

nbd_stderr_fifo="${TEST_DIR}/qemu-nbd.fifo"



# If bash version is >= 4.1, this will be overwritten by a dynamically

# assigned file descriptor value.

nbd_fifo_fd=10



nbd_server_stop()

{
@@ -33,77 +38,62 @@ nbd_server_stop() 
            kill "$NBD_PID"

        fi

    fi

    rm -f "$nbd_unix_socket"

}



nbd_server_wait_for_unix_socket()

{

    pid=$1



    for ((i = 0; i < 300; i++))

    do

        if [ -r "$nbd_unix_socket" ]; then

            return

        fi

        kill -s 0 $pid 2>/dev/null

        if test $? != 0

        then

            echo "qemu-nbd unexpectedly quit"

            exit 1

        fi

        sleep 0.1

    done

    echo "Failed in check of unix socket created by qemu-nbd"

    exit 1

    rm -f "$nbd_unix_socket" "$nbd_stderr_fifo"

}



nbd_server_start_unix_socket()

{

    nbd_server_stop

    $QEMU_NBD -v -t -k "$nbd_unix_socket" "$@" &

    nbd_server_wait_for_unix_socket $!

    $QEMU_NBD -v -t -k "$nbd_unix_socket" --fork "$@"

}



nbd_server_set_tcp_port()

nbd_server_start_tcp_socket()

{

    (ss --help) >/dev/null 2>&1 || _notrun "ss utility not found, skipping test"

    nbd_server_stop



    mkfifo "$nbd_stderr_fifo"

    for ((port = 10809; port <= 10909; port++))

    do

        if ! ss -tln | grep -sqE ":$port\b"; then

        # Redirect stderr to FIFO, so we can later decide whether we

        # want to read it or to redirect it to our stderr, depending

        # on whether the command fails or not

        $QEMU_NBD -v -t -b $nbd_tcp_addr -p $port --fork "$@" \

            2> "$nbd_stderr_fifo" &



        # Taken from common.qemu

        if [[ "${BASH_VERSINFO[0]}" -ge "5" ||

            ("${BASH_VERSINFO[0]}" -ge "4" && "${BASH_VERSINFO[1]}" -ge "1") ]]

        then

            exec {nbd_fifo_fd}<"$nbd_stderr_fifo"

        else

            let _nbd_fifo_fd++

            eval "exec ${_nbd_fifo_fd}<'$nbd_stderr_fifo'"

        fi

        wait $!



        if test $? == 0

        then

            # Success, redirect qemu-nbd's stderr to our stderr

            nbd_tcp_port=$port

            (cat <&$nbd_fifo_fd >&2) &

            eval "exec $nbd_fifo_fd>&-"

            return

        fi

    done



    echo "Cannot find free TCP port for nbd in range 10809-10909"

    exit 1

}



nbd_server_wait_for_tcp_socket()

{

    pid=$1

        # Failure, read the output

        output=$(cat <&$nbd_fifo_fd)

        eval "exec $nbd_fifo_fd>&-"



    for ((i = 0; i < 300; i++))

    do

        if ss -tln | grep -sqE ":$nbd_tcp_port\b"; then

            return

        fi

        kill -s 0 $pid 2>/dev/null

        if test $? != 0

        if ! echo "$output" | grep -q "Address already in use"

        then

            echo "qemu-nbd unexpectedly quit"

            # Unknown error, print it

            echo "$output" >&2

            rm -f "$nbd_stderr_fifo"

            exit 1

        fi

        sleep 0.1

    done

    echo "Failed in check of TCP socket created by qemu-nbd"

    exit 1

}



nbd_server_start_tcp_socket()

{

    nbd_server_stop

    $QEMU_NBD -v -t -b $nbd_tcp_addr -p $nbd_tcp_port "$@" &

    nbd_server_wait_for_tcp_socket $!

    echo "Cannot find free TCP port for nbd in range 10809-10909"

    rm -f "$nbd_stderr_fifo"

    exit 1

}