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>

1 files changed, 42 insertions, 52 deletions

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
 }