[PATCH 18/18] iotests/281: Add test for FUSE exports

[Max Reitz <mreitz@redhat.com>]

We have good coverage of the normal I/O paths now, but what remains is a
test that tests some more special cases: Exporting an image on itself
(thus turning a formatted image into a raw one), some error cases, and
non-writable and non-growable exports.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/281     | 328 +++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/281.out |  92 +++++++++++
 tests/qemu-iotests/group   |   1 +
 3 files changed, 421 insertions(+)
 create mode 100755 tests/qemu-iotests/281
 create mode 100644 tests/qemu-iotests/281.out

diff --git a/tests/qemu-iotests/281 b/tests/qemu-iotests/281
new file mode 100755
index 0000000000..071420697c
--- /dev/null
+++ b/tests/qemu-iotests/281
@@ -0,0 +1,328 @@
+#!/usr/bin/env bash
+#
+# Test FUSE exports (in ways that are not captured by the generic
+# tests)
+#
+# Copyright (C) 2019 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+seq=$(basename "$0")
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+    rmdir "$EXT_MP" 2>/dev/null
+    rm -f "$EXT_MP"
+    rm -f "$COPIED_IMG"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.qemu
+
+# Generic format, but needs a plain filename
+_supported_fmt generic
+if [ "$IMGOPTSSYNTAX" = "true" ]; then
+    _unsupported_fmt $IMGFMT
+fi
+
+_supported_proto file # We create the FUSE export manually
+_supported_os Linux # We need /dev/urandom
+
+# $1: Options (beyond the node-name)
+# $2: Expected return value (defaults to 'return')
+# $3: Node to export (defaults to 'node-format')
+fuse_export_add()
+{
+    _send_qemu_cmd $QEMU_HANDLE \
+        "{'execute': 'fuse-export-add',
+          'arguments': {
+              'node-name': '${3:-node-format}',
+              $1
+          } }" \
+        "${2:-return}" \
+        | _filter_imgfmt
+}
+
+# $1: Mountpoint
+# $2: Expected return value (defaults to 'return')
+fuse_export_remove()
+{
+    _send_qemu_cmd $QEMU_HANDLE \
+        "{'execute': 'fuse-export-remove',
+          'arguments': {
+              'mountpoint': '$1'
+          } }" \
+        "${2:-return}"
+}
+
+# Return the length of the protocol file
+# $1: Protocol node export mount point
+# $2: Original file (to compare)
+get_proto_len()
+{
+    len1=$(stat -c '%s' "$1")
+    len2=$(stat -c '%s' "$2")
+
+    if [ "$len1" != "$len2" ]; then
+        echo 'ERROR: Length of export and original differ:' >&2
+        echo "$len1 != $len2" >&2
+    else
+        echo '(OK: Lengths of export and original are the same)' >&2
+    fi
+
+    echo "$len1"
+}
+
+COPIED_IMG="$TEST_IMG.copy"
+EXT_MP="$TEST_IMG.fuse"
+
+echo '=== Set up ==='
+
+# Create image with random data
+_make_test_img 64M
+$QEMU_IO -c 'write -s /dev/urandom 0 64M' "$TEST_IMG" | _filter_qemu_io
+
+_launch_qemu
+_send_qemu_cmd $QEMU_HANDLE \
+    "{'execute': 'qmp_capabilities'}" \
+    'return'
+
+# Separate blockdev-add calls for format and protocol so we can remove
+# the format layer later on
+_send_qemu_cmd $QEMU_HANDLE \
+    "{'execute': 'blockdev-add',
+      'arguments': {
+          'driver': 'file',
+          'node-name': 'node-protocol',
+          'filename': '$TEST_IMG'
+      } }" \
+    'return'
+
+_send_qemu_cmd $QEMU_HANDLE \
+    "{'execute': 'blockdev-add',
+      'arguments': {
+          'driver': '$IMGFMT',
+          'node-name': 'node-format',
+          'file': 'node-protocol'
+      } }" \
+    'return'
+
+echo
+echo '=== Mountpoint not present ==='
+
+rmdir "$EXT_MP" 2>/dev/null
+rm -f "$EXT_MP"
+output=$(fuse_export_add "'mountpoint': '$EXT_MP'" error)
+
+if echo "$output" | grep -q 'CommandNotFound'; then
+    _notrun 'No FUSE support'
+fi
+
+echo "$output"
+
+echo
+echo '=== Mountpoint is a directory ==='
+
+mkdir "$EXT_MP"
+fuse_export_add "'mountpoint': '$EXT_MP'" error
+rmdir "$EXT_MP"
+
+echo
+echo '=== Mountpoint is a regular file ==='
+
+touch "$EXT_MP"
+fuse_export_add "'mountpoint': '$EXT_MP'"
+
+# Check that the export presents the same data as the original image
+$QEMU_IMG compare -f raw -F $IMGFMT -U "$EXT_MP" "$TEST_IMG"
+
+echo
+echo '=== Mount over existing file ==='
+
+# This is the coolest feature of FUSE exports: You can transparently
+# make images in any format appear as raw images
+fuse_export_add "'mountpoint': '$TEST_IMG'"
+
+# Accesses both exports at the same time, so we get a concurrency test
+$QEMU_IMG compare -f raw -F raw -U "$EXT_MP" "$TEST_IMG"
+
+# Just to be sure, we later want to compare the data offline.  Also,
+# this allows us to see that cp works without complaining.
+# (This is not a given, because cp will expect a short read at EOF.
+# Internally, qemu does not allow short reads, so we have to check
+# whether the FUSE export driver lets them work.)
+cp "$TEST_IMG" "$COPIED_IMG"
+
+# $TEST_IMG will be in mode 0400 because it is read-only; we are going
+# to write to the copy, so make it writable
+chmod 0600 "$COPIED_IMG"
+
+echo
+echo '=== Double export ==='
+
+# We have already seen that exporting a node twice works fine, but you
+# cannot export anything twice on the same mount point.  One reason is
+# that the MP acts as the unique identifier for the export.  The other
+# is that qemu has to stat the given mount point, and this would have
+# to be answered by the same qemu instance if it already has an export
+# there.  However, it cannot answer the stat because it is itself
+# caught up in that same stat.
+fuse_export_add "'mountpoint': '$EXT_MP'" error
+
+echo
+echo '=== Remove export ==='
+
+# Double-check that $EXT_MP appears as a non-empty file (the raw image)
+$QEMU_IMG info -f raw "$EXT_MP" | grep 'virtual size'
+
+fuse_export_remove "$EXT_MP"
+
+# See that the file appears empty again
+$QEMU_IMG info -f raw "$EXT_MP" | grep 'virtual size'
+
+echo
+echo '=== Writable export ==='
+
+fuse_export_add "'mountpoint': '$EXT_MP', 'writable': true"
+
+# Check that writing to the read-only export fails
+$QEMU_IO -f raw -c 'write -P 42 1M 64k' "$TEST_IMG" | _filter_qemu_io
+
+# But here it should work
+$QEMU_IO -f raw -c 'write -P 42 1M 64k' "$EXT_MP" | _filter_qemu_io
+
+# (Adjust the copy, too)
+$QEMU_IO -f raw -c 'write -P 42 1M 64k' "$COPIED_IMG" | _filter_qemu_io
+
+echo
+echo '=== Resizing exports ==='
+
+# Here, we need to export the protocol node -- the format layer may
+# not be growable in principle.
+
+# Remove all exports and the format node first so permissions will not
+# get in the way
+fuse_export_remove "$EXT_MP"
+fuse_export_remove "$TEST_IMG"
+
+_send_qemu_cmd $QEMU_HANDLE \
+    "{'execute': 'blockdev-del',
+      'arguments': {
+          'node-name': 'node-format'
+      } }" \
+    'return'
+
+# Now export the protocol node
+fuse_export_add \
+    "'mountpoint': '$EXT_MP', 'writable': true" \
+    'return' \
+    'node-protocol'
+
+echo
+echo '--- Try growing non-growable export ---'
+
+# Get the current size so we can write beyond the EOF
+orig_len=$(get_proto_len "$EXT_MP" "$TEST_IMG")
+orig_disk_usage=$(stat -c '%b' "$TEST_IMG")
+
+# Should fail (exports are non-growable by default)
+# (Note that qemu-io can never write beyond the EOF, so we have to use
+# dd here)
+dd if=/dev/zero of="$EXT_MP" bs=1 count=64k seek=$orig_len 2>&1 \
+    | _filter_testdir | _filter_imgfmt
+
+echo
+echo '--- Resize export ---'
+
+# But we can truncate it explicitly; even with fallocate
+fallocate -o "$orig_len" -l 64k "$EXT_MP"
+
+new_len=$(get_proto_len "$EXT_MP" "$TEST_IMG")
+if [ "$new_len" != "$((orig_len + 65536))" ]; then
+    echo 'ERROR: Unexpected post-truncate image size:'
+    echo "$new_len != $((orig_len + 65536))"
+else
+    echo 'OK: Post-truncate image size is as expected'
+fi
+
+new_disk_usage=$(stat -c '%b' "$TEST_IMG")
+if [ "$new_disk_usage" -gt "$orig_disk_usage" ]; then
+    echo 'OK: Disk usage grew with fallocate'
+else
+    echo 'ERROR: Disk usage did not grow despite fallocate:'
+    echo "$orig_disk_usage => $new_disk_usage"
+fi
+
+echo
+echo '--- Try growing growable export ---'
+
+# Now export as growable
+fuse_export_remove "$EXT_MP"
+fuse_export_add \
+    "'mountpoint': '$EXT_MP', 'writable': true, 'growable': true" \
+    'return' \
+    'node-protocol'
+
+# Now we should be able to write beyond the EOF
+dd if=/dev/zero of="$EXT_MP" bs=1 count=64k seek=$new_len 2>&1 \
+    | _filter_testdir | _filter_imgfmt
+
+new_len=$(get_proto_len "$EXT_MP" "$TEST_IMG")
+if [ "$new_len" != "$((orig_len + 131072))" ]; then
+    echo 'ERROR: Unexpected post-grow image size:'
+    echo "$new_len != $((orig_len + 131072))"
+else
+    echo 'OK: Post-grow image size is as expected'
+fi
+
+echo
+echo '--- Shrink export ---'
+
+# Now go back to the original size
+truncate -s "$orig_len" "$EXT_MP"
+
+new_len=$(get_proto_len "$EXT_MP" "$TEST_IMG")
+if [ "$new_len" != "$orig_len" ]; then
+    echo 'ERROR: Unexpected post-truncate image size:'
+    echo "$new_len != $orig_len"
+else
+    echo 'OK: Post-truncate image size is as expected'
+fi
+
+echo
+echo '=== Tear down ==='
+
+_send_qemu_cmd $QEMU_HANDLE \
+    "{'execute': 'quit'}" \
+    'return'
+
+wait=yes _cleanup_qemu
+
+echo
+echo '=== Compare copy with original ==='
+
+$QEMU_IMG compare -f raw -F $IMGFMT "$COPIED_IMG" "$TEST_IMG"
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/281.out b/tests/qemu-iotests/281.out
new file mode 100644
index 0000000000..ba41e14b2a
--- /dev/null
+++ b/tests/qemu-iotests/281.out
@@ -0,0 +1,92 @@
+QA output created by 281
+=== Set up ===
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+wrote 67108864/67108864 bytes at offset 0
+64 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+{'execute': 'qmp_capabilities'}
+{"return": {}}
+{'execute': 'blockdev-add', 'arguments': { 'driver': 'file', 'node-name': 'node-protocol', 'filename': 'TEST_DIR/t.IMGFMT' } }
+{"return": {}}
+{'execute': 'blockdev-add', 'arguments': { 'driver': 'IMGFMT', 'node-name': 'node-format', 'file': 'node-protocol' } }
+{"return": {}}
+
+=== Mountpoint not present ===
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-format', 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse' } }
+{"error": {"class": "GenericError", "desc": "Failed to stat 'TEST_DIR/t.IMGFMT.fuse': No such file or directory"}}
+
+=== Mountpoint is a directory ===
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-format', 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse' } }
+{"error": {"class": "GenericError", "desc": "'TEST_DIR/t.IMGFMT.fuse' is not a regular file"}}
+
+=== Mountpoint is a regular file ===
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-format', 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse' } }
+{"return": {}}
+Images are identical.
+
+=== Mount over existing file ===
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-format', 'mountpoint': 'TEST_DIR/t.IMGFMT' } }
+{"return": {}}
+Images are identical.
+
+=== Double export ===
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-format', 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse' } }
+{"error": {"class": "GenericError", "desc": "There already is a FUSE export on 'TEST_DIR/t.IMGFMT.fuse'"}}
+
+=== Remove export ===
+virtual size: 64 MiB (67108864 bytes)
+{'execute': 'fuse-export-remove', 'arguments': { 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse' } }
+{"return": {}}
+virtual size: 0 B (0 bytes)
+
+=== Writable export ===
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-format', 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse', 'writable': true } }
+{"return": {}}
+write failed: Permission denied
+wrote 65536/65536 bytes at offset 1048576
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset 1048576
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+=== Resizing exports ===
+{'execute': 'fuse-export-remove', 'arguments': { 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse' } }
+{"return": {}}
+{'execute': 'fuse-export-remove', 'arguments': { 'mountpoint': 'TEST_DIR/t.IMGFMT' } }
+{"return": {}}
+{'execute': 'blockdev-del', 'arguments': { 'node-name': 'node-format' } }
+{"return": {}}
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-protocol', 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse', 'writable': true } }
+{"return": {}}
+
+--- Try growing non-growable export ---
+(OK: Lengths of export and original are the same)
+dd: error writing 'TEST_DIR/t.IMGFMT.fuse': Input/output error
+1+0 records in
+0+0 records out
+
+--- Resize export ---
+(OK: Lengths of export and original are the same)
+OK: Post-truncate image size is as expected
+OK: Disk usage grew with fallocate
+
+--- Try growing growable export ---
+{'execute': 'fuse-export-remove', 'arguments': { 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse' } }
+{"return": {}}
+{'execute': 'fuse-export-add', 'arguments': { 'node-name': 'node-protocol', 'mountpoint': 'TEST_DIR/t.IMGFMT.fuse', 'writable': true, 'growable': true } }
+{"return": {}}
+65536+0 records in
+65536+0 records out
+(OK: Lengths of export and original are the same)
+OK: Post-grow image size is as expected
+
+--- Shrink export ---
+(OK: Lengths of export and original are the same)
+OK: Post-truncate image size is as expected
+
+=== Tear down ===
+{'execute': 'quit'}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+
+=== Compare copy with original ===
+Images are identical.
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index eb57ddc72c..6fce3f1cfd 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -287,3 +287,4 @@
 273 backing quick
 277 rw quick
 279 rw backing quick
+281 rw
-- 
2.23.0