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authorVenky Shankar <vshankar@redhat.com>2014-06-18 23:36:48 +0530
committerVijay Bellur <vbellur@redhat.com>2014-07-11 00:08:57 -0700
commit6532a65b56a652622612a6edcd03fff90fbeff0f (patch)
tree3b86ab6dc950160f0996ffe5d73d88f11f66c3d4 /tests
parentc7251ebfe8e14090f9420786973c5f8232555b8e (diff)
features/changelog: prevent deadlock on thread cancellation
helper threads (fsync, rollover) wake up periodically and perform their respective operation under a lock (crt->lock). These threads are also subjected to cancellation under some circumstance such as disabling changelog. This is inherently dangerous when funtions which are cancellation points for pthread_cancel(3) are used in the locked region. Consider this pthread_mutex_lock(&mutex); { /* ... */ ret = fsync (fd); <-- cancellation point /* ... */ } pthread_mutex_unlock(&mutex); A pthread_cancel(3) by another thread just before fsync(3) but after pthread_mutex_lock(3) would result in the thread getting cancelled when fsync(3) is invoked, thereby never unlocking the mutex. Moreover, in case of changelog translator, the locked region (under crt->lock in changelog-rt.c) is also the code path for fop changelog updation. Therefore, unlocking the mutex in thread cleanup handler (pthread_cleanup_pop(3)) might prematurely release the mutex during fop updation path. This patch fixes such problems existing in fsync and rollover threads. Fix is to enter the locked region with cancellation disabled and enable it after mutex unlock. Also, test for a cancellation request early on in case none of the functions are cancellation points. Change-Id: I1795627a12827609c1da659d07fc1457ffa033de BUG: 1110917 Signed-off-by: Venky Shankar <vshankar@redhat.com> Reviewed-on: http://review.gluster.org/8106 Reviewed-by: Kotresh HR <khiremat@redhat.com> Reviewed-by: Vijay Bellur <vbellur@redhat.com> Tested-by: Gluster Build System <jenkins@build.gluster.com>
Diffstat (limited to 'tests')
-rw-r--r--tests/bugs/bug-1110917.t39
1 files changed, 39 insertions, 0 deletions
diff --git a/tests/bugs/bug-1110917.t b/tests/bugs/bug-1110917.t
new file mode 100644
index 00000000000..927b2342192
--- /dev/null
+++ b/tests/bugs/bug-1110917.t
@@ -0,0 +1,39 @@
+#!/bin/bash
+
+. $(dirname $0)/../include.rc
+. $(dirname $0)/../volume.rc
+
+cleanup;
+
+TEST glusterd
+TEST pidof glusterd
+
+TEST $CLI volume create $V0 $H0:$B0/brick1 $H0:$B0/brick2;
+TEST $CLI volume start $V0;
+
+TEST glusterfs --volfile-id=/$V0 --volfile-server=$H0 $M0 --attribute-timeout=0 --entry-timeout=0
+
+TEST $CLI volume set $V0 changelog on
+TEST $CLI volume set $V0 changelog.fsync-interval 1
+
+# perform I/O on the background
+f=$(basename `mktemp`)
+dd if=/dev/urandom of=$M0/$f count=100000 bs=4k &
+
+# this is the best we can do without inducing _error points_ in the code
+# without the patch reconfigre() would hang...
+TEST $CLI volume set $V0 changelog.rollover-time `expr $((RANDOM % 9)) + 1`
+TEST $CLI volume set $V0 changelog.rollover-time `expr $((RANDOM % 9)) + 1`
+
+TEST $CLI volume set $V0 changelog off
+TEST $CLI volume set $V0 changelog on
+TEST $CLI volume set $V0 changelog off
+TEST $CLI volume set $V0 changelog on
+
+TEST $CLI volume set $V0 changelog.rollover-time `expr $((RANDOM % 9)) + 1`
+TEST $CLI volume set $V0 changelog.rollover-time `expr $((RANDOM % 9)) + 1`
+
+# if there's a deadlock, this would hang
+wait;
+
+cleanup;