Relax (ref)reservation constraints on ZVOLs

This change allow (ref)reservation to be set larger than the current
ZVOL size: this is safe as we normally set refreservation > volsize
at ZVOL creation time when we account for metadata.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Reviewed by: Richard Elling <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Signed-off-by: loli10K <[email protected]>
Closes #2468 
Closes #6610 

3 files changed, 24 insertions, 37 deletions

diff --git a/tests/zfs-tests/tests/functional/refreserv/refreserv_005_pos.ksh b/tests/zfs-tests/tests/functional/refreserv/refreserv_005_pos.ksh
index a43dd8432..8c044eca5 100755
--- a/tests/zfs-tests/tests/functional/refreserv/refreserv_005_pos.ksh
+++ b/tests/zfs-tests/tests/functional/refreserv/refreserv_005_pos.ksh
@@ -33,13 +33,12 @@
 
 #
 # DESCRIPTION:
-#	Volume refreservation is limited by volsize
+#	Volume (ref)reservation is not limited by volsize
 #
 # STRATEGY:
 #	1. Create volume on filesystem
 #	2. Setting quota for parent filesystem
-#	3. Verify volume refreservation is only limited by volsize
-#	4. Verify volume refreservation can be changed when volsize changed
+#	3. Verify volume (ref)reservation is not limited by volsize
 #
 
 verify_runnable "global"
@@ -51,21 +50,24 @@ function cleanup
 	log_must zfs set mountpoint=$TESTDIR $TESTPOOL/$TESTFS
 }
 
-log_assert "Volume refreservation is limited by volsize"
+log_assert "Volume (ref)reservation is not limited by volsize"
 log_onexit cleanup
 
-fs=$TESTPOOL/$TESTFS; vol=$fs/vol
+fs=$TESTPOOL/$TESTFS
+vol=$fs/vol
 log_must zfs create -V 10M $vol
+refreserv=`get_prop refreservation $vol`
+fudge=1
 
 # Verify the parent filesystem does not affect volume
 log_must zfs set quota=25M $fs
+log_must zfs set reservation=10M $vol
 log_must zfs set refreservation=10M $vol
-avail=$(get_prop mountpoint $vol)
-log_mustnot zfs set refreservation=$avail $vol
 
-# Verify it is affected by volsize
-log_must zfs set volsize=15M $vol
-log_must zfs set refreservation=15M $vol
-log_mustnot zfs set refreservation=16M $vol
+# Verify it is not affected by volsize
+log_must zfs set reservation=$(($refreserv + $fudge)) $vol
+log_must zfs set reservation=$(($refreserv - $fudge)) $vol
+log_must zfs set refreservation=$(($refreserv + $fudge)) $vol
+log_must zfs set refreservation=$(($refreserv - $fudge)) $vol
 
-log_pass "Volume refreservation is limited by volsize"
+log_pass "Volume (ref)reservation is not limited by volsize"
diff --git a/tests/zfs-tests/tests/functional/reservation/reservation_002_pos.sh b/tests/zfs-tests/tests/functional/reservation/reservation_002_pos.sh
index f96010802..202393d4d 100755
--- a/tests/zfs-tests/tests/functional/reservation/reservation_002_pos.sh
+++ b/tests/zfs-tests/tests/functional/reservation/reservation_002_pos.sh
@@ -84,17 +84,9 @@ fi
 
 for obj in $TESTPOOL/$TESTFS $OBJ_LIST ; do
 
-	space_avail=`get_prop available $TESTPOOL`
+	space_avail=`get_prop available $obj`
 	resv_size_set=`expr $space_avail + $RESV_DELTA`
 
-	#
-	# For regular (non-sparse) volumes the upper limit is determined
-	# not by the space available in the pool but rather by the size
-	# of the volume itself.
-	#
-	[[ $obj == $TESTPOOL/$TESTVOL ]] && \
-	    ((resv_size_set = vol_set_size + RESV_DELTA))
-
 	log_must zero_reservation $obj
 	log_mustnot zfs set reservation=$resv_size_set $obj
 
diff --git a/tests/zfs-tests/tests/functional/reservation/reservation_014_pos.sh b/tests/zfs-tests/tests/functional/reservation/reservation_014_pos.sh
index d307917b5..e8bd91d00 100755
--- a/tests/zfs-tests/tests/functional/reservation/reservation_014_pos.sh
+++ b/tests/zfs-tests/tests/functional/reservation/reservation_014_pos.sh
@@ -79,30 +79,23 @@ fi
 
 for obj in $TESTPOOL/$TESTFS $OBJ_LIST ; do
 
-	space_avail=`get_prop available $TESTPOOL`
+	space_avail=`get_prop available $obj`
 	((quota_set_size = space_avail / 3))
 
 	#
-	# A regular (non-sparse) volume's size is effectively
-	# its quota so only need to explicitly set quotas for
-	# filesystems and datasets.
+	# Volumes do not support quota so only need to explicitly
+	# set quotas for filesystems.
 	#
-	# A volumes size is effectively its quota. The maximum
-	# reservation value that can be set on a volume is
-	# determined by the size of the volume or the amount of
-	# space in the pool, whichever is smaller.
+	# The maximum reservation value that can be set on a volume
+	# is determined by the quota set on its parent filesystems or
+	# the amount of space in the pool, whichever is smaller.
 	#
 	if [[ $obj == $TESTPOOL/$TESTFS ]]; then
 		log_must zfs set quota=$quota_set_size $obj
 		((resv_set_size = quota_set_size + RESV_SIZE))
-
-	elif [[ $obj == $TESTPOOL/$TESTVOL2 ]] ; then
-
-		((resv_set_size = sparse_vol_set_size + RESV_SIZE))
-
-	elif [[ $obj == $TESTPOOL/$TESTVOL ]] ; then
-
-		((resv_set_size = vol_set_size + RESV_SIZE))
+	elif [[ $obj == $TESTPOOL/$TESTVOL || $obj == $TESTPOOL/$TESTVOL2 ]]
+	then
+		resv_set_size=`expr $space_avail + $RESV_DELTA`
 	fi
 
 	orig_quota=`get_prop quota $obj`