Add a test for parallel unaligned appends to a file

tests/run_tests.sh

@@ -147,3 +147,4 @@ TEST_NAME=old_csum_4k_dj   OLD=1 OSD_ARGS="--data_csum_type crc32c --inmemory_jo
 TEST_NAME=old_csum_4k      OLD=1 OSD_ARGS="--data_csum_type crc32c" OFFSET_ARGS=$OSD_ARGS ./test_heal.sh
 
 ./test_nfs.sh
+./test_nfs_unaligned_append.sh

tests/test_nfs_unaligned_append.sh

@@ -0,0 +1,25 @@
+#!/bin/bash -ex
+
+GLOBAL_CONFIG=',"client_enable_writeback":false'
+IMMEDIATE_COMMIT=1
+PG_COUNT=16
+. `dirname $0`/run_3osds.sh
+
+build/src/cmd/vitastor-cli --etcd_address $ETCD_URL create -s 10G fsmeta
+build/src/cmd/vitastor-cli --etcd_address $ETCD_URL modify-pool --used-for-app fs:fsmeta testpool
+build/src/nfs/vitastor-nfs start --fs fsmeta --etcd_address $ETCD_URL --portmap 0 --port 2050 --foreground 1 --trace 1 >>./testdata/nfs.log 2>&1 &
+NFS_PID=$!
+
+mkdir -p testdata/nfs
+sudo mount localhost:/ ./testdata/nfs -o port=2050,mountport=2050,nfsvers=3,soft,nolock,tcp
+MNT=$(pwd)/testdata/nfs
+trap "sudo umount -f $MNT"' || true; kill -9 $(jobs -p)' EXIT
+
+dd if=/dev/urandom of=./testdata/ref_data.bin bs=1M count=32 seek=1024B
+build/src/cmd/vitastor-cli --etcd_address $ETCD_URL dd if=./testdata/ref_data.bin of=$MNT/testfile oflag=direct bs=1M iodepth=4 seek=1024B skip=1024B
+cp $MNT/testfile ./testdata/nfs_data.bin
+if ! diff -q ./testdata/ref_data.bin $MNT/testfile; then
+    format_error 'Data lost during parallel unaligned writes to VitastorFS'
+fi
+
+format_green OK