Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2019-06-13' into staging

nbd patches for 2019-06-13

- add 'qemu-nbd --pid-file'
- NBD-related iotest improvements
- NBD code refactoring in preparation for reconnect

# gpg: Signature made Thu 13 Jun 2019 16:37:58 BST
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2019-06-13:
  block/nbd: merge NBDClientSession struct back to BDRVNBDState
  block/nbd: merge nbd-client.* to nbd.c
  block/nbd-client: drop stale logout
  nbd/server: Nicer spelling of max BLOCK_STATUS reply length
  iotests: Let 233 run concurrently
  iotests: Use qemu-nbd's --pid-file
  qemu-nbd: Do not close stderr
  iotests.py: Add qemu_nbd_early_pipe()
  qemu-nbd: Add --pid-file option

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

5 files changed, 52 insertions, 62 deletions

diff --git a/tests/qemu-iotests/147 b/tests/qemu-iotests/147
index 82513279b0..2d84fddb01 100755
--- a/tests/qemu-iotests/147
+++ b/tests/qemu-iotests/147
@@ -24,7 +24,7 @@ import socket
 import stat
 import time
 import iotests
-from iotests import cachemode, imgfmt, qemu_img, qemu_nbd, qemu_nbd_pipe
+from iotests import cachemode, imgfmt, qemu_img, qemu_nbd, qemu_nbd_early_pipe
 
 NBD_PORT_START      = 32768
 NBD_PORT_END        = NBD_PORT_START + 1024
@@ -93,7 +93,7 @@ class QemuNBD(NBDBlockdevAddBase):
             pass
 
     def _try_server_up(self, *args):
-        status, msg = qemu_nbd_pipe('-f', imgfmt, test_img, *args)
+        status, msg = qemu_nbd_early_pipe('-f', imgfmt, test_img, *args)
         if status == 0:
             return True
         if 'Address already in use' in msg:
diff --git a/tests/qemu-iotests/233 b/tests/qemu-iotests/233
index 057cad2044..a5c17c3963 100755
--- a/tests/qemu-iotests/233
+++ b/tests/qemu-iotests/233
@@ -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
diff --git a/tests/qemu-iotests/common.nbd b/tests/qemu-iotests/common.nbd
index 25fc9ffaa4..24b01b60aa 100644
--- a/tests/qemu-iotests/common.nbd
+++ b/tests/qemu-iotests/common.nbd
@@ -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
 }
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 93f87389b6..5502c3da2f 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -105,10 +105,8 @@ _qemu_io_wrapper()
 
 _qemu_nbd_wrapper()
 {
-    (
-        echo $BASHPID > "${QEMU_TEST_DIR}/qemu-nbd.pid"
-        exec "$QEMU_NBD_PROG" $QEMU_NBD_OPTIONS "$@"
-    )
+    "$QEMU_NBD_PROG" --pid-file="${QEMU_TEST_DIR}/qemu-nbd.pid" \
+                     $QEMU_NBD_OPTIONS "$@"
 }
 
 _qemu_vxhs_wrapper()
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 6bcddd8870..f11482f3dc 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -209,9 +209,9 @@ def qemu_nbd(*args):
     '''Run qemu-nbd in daemon mode and return the parent's exit code'''
     return subprocess.call(qemu_nbd_args + ['--fork'] + list(args))
 
-def qemu_nbd_pipe(*args):
+def qemu_nbd_early_pipe(*args):
     '''Run qemu-nbd in daemon mode and return both the parent's exit code
-       and its output'''
+       and its output in case of an error'''
     subp = subprocess.Popen(qemu_nbd_args + ['--fork'] + list(args),
                             stdout=subprocess.PIPE,
                             stderr=subprocess.STDOUT,
@@ -221,7 +221,10 @@ def qemu_nbd_pipe(*args):
         sys.stderr.write('qemu-nbd received signal %i: %s\n' %
                          (-exitcode,
                           ' '.join(qemu_nbd_args + ['--fork'] + list(args))))
-    return exitcode, subp.communicate()[0]
+    if exitcode == 0:
+        return exitcode, ''
+    else:
+        return exitcode, subp.communicate()[0]
 
 def compare_images(img1, img2, fmt1=imgfmt, fmt2=imgfmt):
     '''Return True if two image files are identical'''