nfs: make it possible to disable nfs.mount-rmtab

When there are many NFS-clients doing very often mount/unmount actions,
the updating of the 'rmtab' can become a bottleneck and cause delays. In
these situations, the output of 'showmount' may be less important than
the responsiveness of the (un)mounting.

By setting 'nfs.mount-rmtab' to the value "/-", the cache file is not
updated anymore, and the entries are only kept in memory.

Cherry picked from commit 40407afb529f6e5fa2f79e9778c2f527122d75eb:
> Cherry picked from commit 331ef6e1a86bfc0a93f8a9dec6ad35c417873849:
>> BUG: 1169317
>> Change-Id: I40c4d8d754932f86fb2b1b2588843390464c773d
>> Reported-by: Cyril Peponnet <cyril@peponnet.fr>
>> Signed-off-by: Niels de Vos <ndevos@redhat.com>
>> Reviewed-on: http://review.gluster.org/9223
>> Tested-by: Gluster Build System <jenkins@build.gluster.com>
>> Reviewed-by: soumya k <skoduri@redhat.com>
>> Reviewed-by: jiffin tony Thottan <jthottan@redhat.com>
>> Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
>
> This change also contains the fixes to the test-case from:
>>
>> nfs: fix spurious failure in bug-1166862.t
>>
>> In some environments, "showmount" could return an NFS-client that does
>> not start with "1". This would cause the test-case to fail. The check is
>> incorrect, the number of lines should get counted instead.
>>
>> Also moving the test-case to the .../nfs/... subdirectory.
>>
>> Cherry picked from commit ee9b35a780607daddc2832b9af5ed6bf414aebc0:
>> BUG: 1166862
>> Change-Id: Ic03aa8145ca57d78aea01564466e924b03bb302a
>> Signed-off-by: Niels de Vos <ndevos@redhat.com>
>> Reviewed-on: http://review.gluster.org/10419
>> Tested-by: Gluster Build System <jenkins@build.gluster.com>
>> Reviewed-by: Vijay Bellur <vbellur@redhat.com>
>>
>
> Change-Id: I40c4d8d754932f86fb2b1b2588843390464c773d
> BUG: 1215385
> Signed-off-by: Niels de Vos <ndevos@redhat.com>
> Reviewed-on: http://review.gluster.org/10379
> Tested-by: NetBSD Build System
> Tested-by: Gluster Build System <jenkins@build.gluster.com>
> Reviewed-by: Vijay Bellur <vbellur@redhat.com>

Change-Id: I40c4d8d754932f86fb2b1b2588843390464c773d
BUG: 1234096
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/11335
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra Bhat <raghavendra@redhat.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/tests/bugs/nfs/bug-1166862.t b/tests/bugs/nfs/bug-1166862.t
new file mode 100755
index 00000000000..c8f63d50b0c
--- /dev/null
+++ b/tests/bugs/nfs/bug-1166862.t
@@ -0,0 +1,66 @@
+#!/bin/bash
+#
+# When nfs.mount-rmtab is disabled, it should not get updated.
+#
+# Based on: bug-904065.t
+#
+
+# count the lines of a file, return 0 if the file does not exist
+function count_lines()
+{
+        if [ -n "$1" ]
+        then
+                $@ 2>/dev/null | wc -l
+        else
+                echo 0
+        fi
+}
+
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../nfs.rc
+. $(dirname $0)/../../volume.rc
+
+cleanup
+
+TEST glusterd
+TEST pidof glusterd
+
+TEST $CLI volume create $V0 $H0:$B0/brick1
+EXPECT 'Created' volinfo_field $V0 'Status'
+
+TEST $CLI volume start $V0;
+EXPECT 'Started' volinfo_field $V0 'Status'
+
+# glusterfs/nfs needs some time to start up in the background
+EXPECT_WITHIN $NFS_EXPORT_TIMEOUT 1 is_nfs_export_available
+
+# disable the rmtab by settting it to the magic "/-" value
+TEST $CLI volume set $V0 nfs.mount-rmtab /-
+
+# before mounting the rmtab should be empty
+EXPECT '0' count_lines cat $GLUSTERD_WORKDIR/nfs/rmtab
+
+TEST mount_nfs $H0:/$V0 $N0 nolock
+EXPECT '0' count_lines cat $GLUSTERD_WORKDIR/nfs/rmtab
+
+# showmount should list one client
+EXPECT '1' count_lines showmount --no-headers $H0
+
+# unmount
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $N0
+
+# after resetting the option, the rmtab should get updated again
+TEST $CLI volume reset $V0 nfs.mount-rmtab
+
+# before mounting the rmtab should be empty
+EXPECT '0' count_lines cat $GLUSTERD_WORKDIR/nfs/rmtab
+
+TEST mount_nfs $H0:/$V0 $N0 nolock
+EXPECT '2' count_lines cat $GLUSTERD_WORKDIR/nfs/rmtab
+
+# removing a mount
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $N0
+EXPECT '0' count_lines cat $GLUSTERD_WORKDIR/nfs/rmtab
+
+cleanup