cluster/dht: Bug fixes to cluster.min-free-disk

Summary:
- Enforces FUSE/gNFSd/SHD/rebalance rejection of writes when all subvolumes are
  beyond the value set in "cluster.min-free-disk"
- Fixes existing code paths to be more intuitive & straightforward
- Write path now honors min-free-disk
- Adds test to ensure feature doesn't break in future
- This is a port of D2981282 to 3.8

Signed-off-by: Shreyas Siravara <sshreyas@fb.com>

Change-Id: I76923bf76178fe589aa1a26bd1970cf8d009642a
Reviewed-on: http://review.gluster.org/16153
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Shreyas Siravara <sshreyas@fb.com>
Tested-by: Shreyas Siravara <sshreyas@fb.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

4 files changed, 82 insertions, 1 deletions

diff --git a/tests/basic/dht-min-free-space.t b/tests/basic/dht-min-free-space.t
new file mode 100755
index 00000000000..17d10cc39a5
--- /dev/null
+++ b/tests/basic/dht-min-free-space.t
@@ -0,0 +1,78 @@
+#!/bin/bash
+
+. $(dirname $0)/../include.rc
+. $(dirname $0)/../volume.rc
+
+cleanup;
+
+grep $B0/patchy1 /proc/mounts &> /dev/null && umount $B0/patchy1
+grep $B0/patchy2 /proc/mounts &> /dev/null && umount $B0/patchy2
+losetup -d /dev/loop0 2> /dev/null
+losetup -d /dev/loop1 2> /dev/null
+mkdir $B0/${V0}{1..2}
+
+TEST glusterd
+
+TEST dd if=/dev/zero of=/tmp/${V0}-dev1 bs=1M count=30
+TEST dd if=/dev/zero of=/tmp/${V0}-dev2 bs=1M count=30
+
+TEST losetup /dev/loop0 /tmp/${V0}-dev1
+TEST losetup /dev/loop1 /tmp/${V0}-dev2
+
+TEST mkfs.xfs /dev/loop0
+TEST mkfs.xfs /dev/loop1
+
+TEST mount /dev/loop0 $B0/${V0}1
+TEST mount /dev/loop1 $B0/${V0}2
+
+TEST $CLI volume create $V0 $H0:$B0/${V0}1 $H0:$B0/${V0}2
+TEST $CLI volume set $V0 cluster.min-free-disk 2MB
+TEST $CLI volume set $V0 cluster.min-free-strict-mode on
+TEST $CLI volume set $V0 cluster.du-refresh-interval-sec 0
+TEST $CLI volume start $V0
+
+TEST glusterfs --volfile-id=$V0 --volfile-server=$H0 $M0
+
+####################################
+# Test re-directs of file creation #
+####################################
+
+# This should work, no redirects
+TEST dd if=/dev/zero of=$M0/testfile1 bs=1M count=8
+TEST [ -f /d/backends/${V0}2/testfile1 ] && [ ! -k /d/backends/${V0}1/testfile1 ]
+
+TEST $CLI volume set $V0 cluster.min-free-disk 19MB
+
+# This should work, & the file redirected
+# Subvolume 2 should have the linkto &
+# Subvolume 1 should have the original
+TEST dd if=/dev/zero of=$M0/testfile3 bs=1M count=4
+TEST [ -f /d/backends/${V0}1/testfile3 ] && [ ! -k /d/backends/${V0}1/testfile3 ]
+TEST [ -k /d/backends/${V0}2/testfile3 ]
+
+# This should fail, cluster is full
+TEST ! dd if=/dev/zero of=$M0/testfile2 bs=1M count=23
+
+###################
+# Strict mode off #
+###################
+TEST $CLI volume set $V0 cluster.min-free-strict-mode off
+TEST dd if=/dev/zero of=$M0/testfile1 bs=1M count=20
+TEST rm -f $M0/testfile1
+
+###################
+# Strict mode on #
+###################
+TEST $CLI volume set $V0 cluster.min-free-strict-mode on
+TEST ! dd if=/dev/zero of=$M0/testfile1 bs=1M count=16
+TEST rm -f $M0/testfile1
+
+killall gluster{fs,fsd,d}
+
+umount -lf $B0/${V0}1
+umount -lf $B0/${V0}2
+
+losetup -d /dev/loop0
+losetup -d /dev/loop1
+
+cleanup;
diff --git a/tests/basic/gfproxy.t b/tests/basic/gfproxy.t
index 58794394807..71c6788db76 100644
--- a/tests/basic/gfproxy.t
+++ b/tests/basic/gfproxy.t
@@ -62,7 +62,7 @@ TEST [ "$(md5sum $M0/testfile1 | awk '{print $1}')" == "$md5" ]
 
 rm /tmp/testfile1
 
-dd if=/dev/zero of=$N0/bigfile bs=1M count=10240 &
+dd if=/dev/zero of=$N0/bigfile bs=1M count=3072 &
 BG_STRESS_PID=$!
 
 sleep 3
diff --git a/tests/bugs/distribute/bug-1099890.t b/tests/bugs/distribute/bug-1099890.t
index 40f70d4938b..29ceccf2309 100644
--- a/tests/bugs/distribute/bug-1099890.t
+++ b/tests/bugs/distribute/bug-1099890.t
@@ -44,6 +44,8 @@ TEST   $CLI volume set $V0 features.quota-deem-statfs on
 
 TEST   $CLI volume quota $V0 limit-usage / 150MB;
 
+TEST   $CLI volume set $V0 cluster.du-refresh-interval-sec 1
+
 TEST   $CLI volume set $V0 cluster.min-free-disk 50%
 
 TEST   glusterfs -s $H0 --volfile-id=$V0 $M0
diff --git a/tests/bugs/fuse/bug-858488-min-free-disk.t b/tests/bugs/fuse/bug-858488-min-free-disk.t
index 635dc04d1e6..ab636575d3f 100644
--- a/tests/bugs/fuse/bug-858488-min-free-disk.t
+++ b/tests/bugs/fuse/bug-858488-min-free-disk.t
@@ -23,6 +23,7 @@ TEST MOUNT_LOOP $LO2 $B0/${V0}2
 
 ## Lets create volume
 TEST $CLI volume create $V0 $H0:$B0/${V0}{1,2};
+TEST $CLI volume set $V0 cluster.du-refresh-interval-sec 1
 
 ## Verify volume is created
 EXPECT "$V0" volinfo_field $V0 'Volume Name';