core: glusterfsd keeping fd open in index xlator

Problem: At the time of processing GF_EVENT_PARENT_DOWN
         at brick xlator, it forwards the event to next xlator
         only while xlator ensures no stub is in progress.
         At io-thread xlator it decreases stub_cnt before the process
         a stub and notify EVENT to next xlator

Solution: Introduce a new counter to save stub_cnt and decrease
          the counter after process the stub completely at io-thread
          xlator.
          To avoid brick crash at the time of call xlator_mem_cleanup
          move only brick xlator if detach brick name has found in
          the graph

Note: Thanks to pranith for sharing a simple reproducer to
      reproduce the same

fixes bz#1637934
Change-Id: I1a694a001f7a5417e8771e3adf92c518969b6baa
Signed-off-by: Mohit Agrawal <moagrawal@redhat.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/tests/bugs/glusterd/brick-mux-fd-cleanup.t b/tests/bugs/glusterd/brick-mux-fd-cleanup.t
new file mode 100644
index 00000000000..de11c177b8a
--- /dev/null
+++ b/tests/bugs/glusterd/brick-mux-fd-cleanup.t
@@ -0,0 +1,78 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+#This .t tests that the fds from client are closed on brick when gluster volume
+#stop is executed in brick-mux setup.
+
+cleanup;
+TEST glusterd
+TEST pidof glusterd
+
+function keep_fd_open {
+#This function has to be run as background job because opening the fd in
+#foreground and running commands is leading to flush calls on these fds
+#which is making it very difficult to create the race where fds will be left
+#open even after the brick dies.
+    exec 5>$M1/a
+    exec 6>$M1/b
+    while [ -f $M0/a ]; do sleep 1; done
+}
+
+function count_open_files {
+    local brick_pid="$1"
+    local pattern="$2"
+    ls -l /proc/$brick_pid/fd | grep -i "$pattern" | wc -l
+}
+
+TEST $CLI volume set all cluster.brick-multiplex on
+TEST $CLI volume create $V0 replica 2 $H0:$B0/${V0}{0,1}
+TEST $CLI volume create $V1 replica 2 $H0:$B0/${V1}{2,3}
+#Have same configuration on both bricks so that they are multiplexed
+#Delay flush fop for a second
+TEST $CLI volume heal $V0 disable
+TEST $CLI volume heal $V1 disable
+TEST $CLI volume set $V0 delay-gen posix
+TEST $CLI volume set $V0 delay-gen.enable flush
+TEST $CLI volume set $V0 delay-gen.delay-percentage 100
+TEST $CLI volume set $V0 delay-gen.delay-duration 1000000
+TEST $CLI volume set $V1 delay-gen posix
+TEST $CLI volume set $V1 delay-gen.enable flush
+TEST $CLI volume set $V1 delay-gen.delay-percentage 100
+TEST $CLI volume set $V1 delay-gen.delay-duration 1000000
+
+TEST $CLI volume start $V0
+TEST $CLI volume start $V1
+
+TEST $GFS -s $H0 --volfile-id=$V0 --direct-io-mode=enable $M0
+TEST $GFS -s $H0 --volfile-id=$V1 --direct-io-mode=enable $M1
+
+TEST touch $M0/a
+keep_fd_open &
+TEST $CLI volume profile $V1 start
+brick_pid=$(get_brick_pid $V1 $H0 $B0/${V1}2)
+TEST count_open_files $brick_pid "$B0/${V1}2/a"
+TEST count_open_files $brick_pid "$B0/${V1}2/b"
+TEST count_open_files $brick_pid "$B0/${V1}3/a"
+TEST count_open_files $brick_pid "$B0/${V1}3/b"
+
+#If any other flush fops are introduced into the system other than the one at
+#cleanup it interferes with the race, so test for it
+EXPECT "^0$" echo "$($CLI volume profile $V1 info incremental | grep -i flush | wc -l)"
+#Stop the volume
+TEST $CLI volume stop $V1
+
+#Wait for cleanup resources or volume V1
+EXPECT_WITHIN $GRAPH_SWITCH_TIMEOUT "^0$" count_open_files $brick_pid "$B0/${V1}2/a"
+EXPECT_WITHIN $GRAPH_SWITCH_TIMEOUT "^0$" count_open_files $brick_pid "$B0/${V1}2/b"
+EXPECT_WITHIN $GRAPH_SWITCH_TIMEOUT "^0$" count_open_files $brick_pid "$B0/${V1}3/a"
+EXPECT_WITHIN $GRAPH_SWITCH_TIMEOUT "^0$" count_open_files $brick_pid "$B0/${V1}3/b"
+
+TEST rm -f $M0/a #Exit keep_fd_open()
+wait
+
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $M0
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $M1
+
+cleanup