nbd patches for 2018-07-02

Bug fixes and iotest exposure of fleecing via NBD (serving a
 read-only point-in-time view via blockdev-backup sync:none,
 as well as serving dirty bitmaps over NBD), including a new
 x-dirty-bitmap parameter when opening NBD clients as the
 counterpart to x-nbd-server-add-bitmap. Also a random fix
 for iscsi block_status spotted by Coverity that missed other
 miscellaneous trees.
 
 - Eric Blake: nbd/server: Fix dirty bitmap logic regression
 - Eric Blake: iscsi: Avoid potential for get_status overflow
 - John Snow/Vladimir Sementsov-Ogievskiy: 0/2 block: formalize and test fleecing
 - Eric Blake: 0/2 test NBD bitmap export
 -----BEGIN PGP SIGNATURE-----
 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg
 
 iQEcBAABCAAGBQJbOtJPAAoJEKeha0olJ0NqEvwH/3FwWnlBdBvdYGgPjzGE1Atm
 ofCKcyxE/2VJtxeWlZQHzs1VqSq81s7am5SdzOrIWnQekvHFcLu6/71RABiauzMd
 neCvVOrXOVdktj1i1Z2Gg4BgjDmqbTDlo5ssVh/oXP0Zebi6OZFfQrB7y3cGBvui
 4XI7lW9qJxt6F1FlKloXnofWRDENyo5vgdz6QjQXfauthw2T5045RIPTfiz03FCp
 fbs+6K0+bKxfPdNLrqxxOZo/loYnEXbDYv6VBAIWBqztXVnMHxCqnh0YN05jwsfF
 TRW0/YT8lpWarOZ1soIC6a/OGXQZbxgRhZ+Zr+Wa2jw0YNHJanU9isxi37aUqQo=
 =Xivx
 -----END PGP SIGNATURE-----

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2018-07-02' into staging

nbd patches for 2018-07-02

Bug fixes and iotest exposure of fleecing via NBD (serving a
read-only point-in-time view via blockdev-backup sync:none,
as well as serving dirty bitmaps over NBD), including a new
x-dirty-bitmap parameter when opening NBD clients as the
counterpart to x-nbd-server-add-bitmap. Also a random fix
for iscsi block_status spotted by Coverity that missed other
miscellaneous trees.

- Eric Blake: nbd/server: Fix dirty bitmap logic regression
- Eric Blake: iscsi: Avoid potential for get_status overflow
- John Snow/Vladimir Sementsov-Ogievskiy: 0/2 block: formalize and test fleecing
- Eric Blake: 0/2 test NBD bitmap export

# gpg: Signature made Tue 03 Jul 2018 02:33:03 BST
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2018-07-02:
  iotests: New test 223 for exporting dirty bitmap over NBD
  nbd/client: Add x-dirty-bitmap to query bitmap from server
  iotests: add 222 to test basic fleecing
  blockdev: enable non-root nodes for backup source
  iscsi: Avoid potential for get_status overflow
  nbd/server: Fix dirty bitmap logic regression

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

block/iscsi.c

@@ -734,7 +734,7 @@ retry:
         goto out_unlock;
     }
 
-    *pnum = lbasd->num_blocks * iscsilun->block_size;
+    *pnum = (int64_t) lbasd->num_blocks * iscsilun->block_size;
 
     if (lbasd->provisioning == SCSI_PROVISIONING_TYPE_DEALLOCATED ||
         lbasd->provisioning == SCSI_PROVISIONING_TYPE_ANCHORED) {

block/nbd-client.c

@@ -970,6 +970,7 @@ int nbd_client_init(BlockDriverState *bs,
                     const char *export,
                     QCryptoTLSCreds *tlscreds,
                     const char *hostname,
+                    const char *x_dirty_bitmap,
                     Error **errp)
 {
     NBDClientSession *client = nbd_get_client_session(bs);
@@ -982,9 +983,11 @@ int nbd_client_init(BlockDriverState *bs,
     client->info.request_sizes = true;
     client->info.structured_reply = true;
     client->info.base_allocation = true;
+    client->info.x_dirty_bitmap = g_strdup(x_dirty_bitmap);
     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), export,
                                 tlscreds, hostname,
                                 &client->ioc, &client->info, errp);
+    g_free(client->info.x_dirty_bitmap);
     if (ret < 0) {
         logout("Failed to negotiate with the NBD server\n");
         return ret;

block/nbd-client.h

@@ -45,6 +45,7 @@ int nbd_client_init(BlockDriverState *bs,
                     const char *export_name,
                     QCryptoTLSCreds *tlscreds,
                     const char *hostname,
+                    const char *x_dirty_bitmap,
                     Error **errp);
 void nbd_client_close(BlockDriverState *bs);
 

block/nbd.c

@@ -378,6 +378,12 @@ static QemuOptsList nbd_runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "ID of the TLS credentials to use",
         },
+        {
+            .name = "x-dirty-bitmap",
+            .type = QEMU_OPT_STRING,
+            .help = "experimental: expose named dirty bitmap in place of "
+                    "block status",
+        },
         { /* end of list */ }
     },
 };
@@ -438,8 +444,8 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* NBD handshake */
-    ret = nbd_client_init(bs, sioc, s->export,
+    ret = nbd_client_init(bs, sioc, s->export, tlscreds, hostname,
-                          tlscreds, hostname, errp);
+                          qemu_opt_get(opts, "x-dirty-bitmap"), errp);
  error:
     if (sioc) {
         object_unref(OBJECT(sioc));

blockdev.c

@@ -1859,7 +1859,7 @@ static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
     assert(common->action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
     backup = common->action->u.blockdev_backup.data;
 
-    bs = qmp_get_root_bs(backup->device, errp);
+    bs = bdrv_lookup_bs(backup->device, backup->device, errp);
     if (!bs) {
         return;
     }
@@ -3517,7 +3517,7 @@ BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
         backup->compress = false;
     }
 
-    bs = qmp_get_root_bs(backup->device, errp);
+    bs = bdrv_lookup_bs(backup->device, backup->device, errp);
     if (!bs) {
         return NULL;
     }

include/block/nbd.h

@@ -259,6 +259,7 @@ static inline bool nbd_reply_type_is_error(int type)
 struct NBDExportInfo {
     /* Set by client before nbd_receive_negotiate() */
     bool request_sizes;
+    char *x_dirty_bitmap;
 
     /* In-out fields, set by client before nbd_receive_negotiate() and
      * updated by server results during nbd_receive_negotiate() */

nbd/client.c

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2016-2017 Red Hat, Inc.
+ *  Copyright (C) 2016-2018 Red Hat, Inc.
  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
  *
  *  Network Block Device Client Side
@@ -831,7 +831,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name,
 
             if (info->structured_reply && base_allocation) {
                 result = nbd_negotiate_simple_meta_context(
-                        ioc, name, "base:allocation",
+                        ioc, name, info->x_dirty_bitmap ?: "base:allocation",
                         &info->meta_base_allocation_id, errp);
                 if (result < 0) {
                     goto fail;

nbd/server.c

@@ -1977,7 +1977,7 @@ static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
 
     bdrv_dirty_bitmap_unlock(bitmap);
 
-    assert(offset > end);
+    assert(offset < end);
     *length = end - offset;
     return i;
 }

qapi/block-core.json

@@ -3471,12 +3471,17 @@
 #
 # @tls-creds:   TLS credentials ID
 #
+# @x-dirty-bitmap: A "qemu:dirty-bitmap:NAME" string to query in place of
+#                  traditional "base:allocation" block status (see
+#                  NBD_OPT_LIST_META_CONTEXT in the NBD protocol) (since 3.0)
+#
 # Since: 2.9
 ##
 { 'struct': 'BlockdevOptionsNbd',
   'data': { 'server': 'SocketAddress',
             '*export': 'str',
-            '*tls-creds': 'str' } }
+            '*tls-creds': 'str',
+            '*x-dirty-bitmap': 'str' } }
 
 ##
 # @BlockdevOptionsRaw:

tests/qemu-iotests/222

@@ -0,0 +1,155 @@
+#!/usr/bin/env python
+#
+# This test covers the basic fleecing workflow, which provides a
+# point-in-time snapshot of a node that can be queried over NBD.
+#
+# Copyright (C) 2018 Red Hat, Inc.
+# John helped, too.
+#
+# 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/>.
+#
+# Creator/Owner: John Snow <jsnow@redhat.com>
+
+import iotests
+from iotests import log, qemu_img, qemu_io, qemu_io_silent
+
+iotests.verify_platform(['linux'])
+
+patterns = [("0x5d", "0",         "64k"),
+            ("0xd5", "1M",        "64k"),
+            ("0xdc", "32M",       "64k"),
+            ("0xcd", "0x3ff0000", "64k")]  # 64M - 64K
+
+overwrite = [("0xab", "0",         "64k"), # Full overwrite
+             ("0xad", "0x00f8000", "64k"), # Partial-left (1M-32K)
+             ("0x1d", "0x2008000", "64k"), # Partial-right (32M+32K)
+             ("0xea", "0x3fe0000", "64k")] # Adjacent-left (64M - 128K)
+
+zeroes = [("0", "0x00f8000", "32k"), # Left-end of partial-left (1M-32K)
+          ("0", "0x2010000", "32k"), # Right-end of partial-right (32M+64K)
+          ("0", "0x3fe0000", "64k")] # overwrite[3]
+
+remainder = [("0xd5", "0x108000",  "32k"), # Right-end of partial-left [1]
+             ("0xdc", "32M",       "32k"), # Left-end of partial-right [2]
+             ("0xcd", "0x3ff0000", "64k")] # patterns[3]
+
+with iotests.FilePath('base.img') as base_img_path, \
+     iotests.FilePath('fleece.img') as fleece_img_path, \
+     iotests.FilePath('nbd.sock') as nbd_sock_path, \
+     iotests.VM() as vm:
+
+    log('--- Setting up images ---')
+    log('')
+
+    assert qemu_img('create', '-f', iotests.imgfmt, base_img_path, '64M') == 0
+    assert qemu_img('create', '-f', "qcow2", fleece_img_path, '64M') == 0
+
+    for p in patterns:
+        qemu_io('-f', iotests.imgfmt,
+                '-c', 'write -P%s %s %s' % p, base_img_path)
+
+    log('Done')
+
+    log('')
+    log('--- Launching VM ---')
+    log('')
+
+    vm.add_drive(base_img_path)
+    vm.launch()
+    log('Done')
+
+    log('')
+    log('--- Setting up Fleecing Graph ---')
+    log('')
+
+    src_node = "drive0"
+    tgt_node = "fleeceNode"
+
+    # create tgt_node backed by src_node
+    log(vm.qmp("blockdev-add", **{
+        "driver": "qcow2",
+        "node-name": tgt_node,
+        "file": {
+            "driver": "file",
+            "filename": fleece_img_path,
+        },
+        "backing": src_node,
+    }))
+
+    # Establish COW from source to fleecing node
+    log(vm.qmp("blockdev-backup",
+               device=src_node,
+               target=tgt_node,
+               sync="none"))
+
+    log('')
+    log('--- Setting up NBD Export ---')
+    log('')
+
+    nbd_uri = 'nbd+unix:///%s?socket=%s' % (tgt_node, nbd_sock_path)
+    log(vm.qmp("nbd-server-start",
+               **{"addr": { "type": "unix",
+                            "data": { "path": nbd_sock_path } } }))
+
+    log(vm.qmp("nbd-server-add", device=tgt_node))
+
+    log('')
+    log('--- Sanity Check ---')
+    log('')
+
+    for p in (patterns + zeroes):
+        cmd = "read -P%s %s %s" % p
+        log(cmd)
+        assert qemu_io_silent('-r', '-f', 'raw', '-c', cmd, nbd_uri) == 0
+
+    log('')
+    log('--- Testing COW ---')
+    log('')
+
+    for p in overwrite:
+        cmd = "write -P%s %s %s" % p
+        log(cmd)
+        log(vm.hmp_qemu_io(src_node, cmd))
+
+    log('')
+    log('--- Verifying Data ---')
+    log('')
+
+    for p in (patterns + zeroes):
+        cmd = "read -P%s %s %s" % p
+        log(cmd)
+        assert qemu_io_silent('-r', '-f', 'raw', '-c', cmd, nbd_uri) == 0
+
+    log('')
+    log('--- Cleanup ---')
+    log('')
+
+    log(vm.qmp('block-job-cancel', device=src_node))
+    log(vm.event_wait('BLOCK_JOB_CANCELLED'),
+        filters=[iotests.filter_qmp_event])
+    log(vm.qmp('nbd-server-stop'))
+    log(vm.qmp('blockdev-del', node_name=tgt_node))
+    vm.shutdown()
+
+    log('')
+    log('--- Confirming writes ---')
+    log('')
+
+    for p in (overwrite + remainder):
+        cmd = "read -P%s %s %s" % p
+        log(cmd)
+        assert qemu_io_silent(base_img_path, '-c', cmd) == 0
+
+    log('')
+    log('Done')

tests/qemu-iotests/222.out

@@ -0,0 +1,67 @@
+--- Setting up images ---
+
+Done
+
+--- Launching VM ---
+
+Done
+
+--- Setting up Fleecing Graph ---
+
+{u'return': {}}
+{u'return': {}}
+
+--- Setting up NBD Export ---
+
+{u'return': {}}
+{u'return': {}}
+
+--- Sanity Check ---
+
+read -P0x5d 0 64k
+read -P0xd5 1M 64k
+read -P0xdc 32M 64k
+read -P0xcd 0x3ff0000 64k
+read -P0 0x00f8000 32k
+read -P0 0x2010000 32k
+read -P0 0x3fe0000 64k
+
+--- Testing COW ---
+
+write -P0xab 0 64k
+{u'return': u''}
+write -P0xad 0x00f8000 64k
+{u'return': u''}
+write -P0x1d 0x2008000 64k
+{u'return': u''}
+write -P0xea 0x3fe0000 64k
+{u'return': u''}
+
+--- Verifying Data ---
+
+read -P0x5d 0 64k
+read -P0xd5 1M 64k
+read -P0xdc 32M 64k
+read -P0xcd 0x3ff0000 64k
+read -P0 0x00f8000 32k
+read -P0 0x2010000 32k
+read -P0 0x3fe0000 64k
+
+--- Cleanup ---
+
+{u'return': {}}
+{u'timestamp': {u'seconds': 'SECS', u'microseconds': 'USECS'}, u'data': {u'device': u'drive0', u'type': u'backup', u'speed': 0, u'len': 67108864, u'offset': 393216}, u'event': u'BLOCK_JOB_CANCELLED'}
+{u'return': {}}
+{u'return': {}}
+
+--- Confirming writes ---
+
+read -P0xab 0 64k
+read -P0xad 0x00f8000 64k
+read -P0x1d 0x2008000 64k
+read -P0xea 0x3fe0000 64k
+read -P0xd5 0x108000 32k
+read -P0xdc 32M 32k
+read -P0xcd 0x3ff0000 64k
+
+Done

tests/qemu-iotests/223

@@ -0,0 +1,138 @@
+#!/bin/bash
+#
+# Test reading dirty bitmap over NBD
+#
+# Copyright (C) 2018 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 $seq"
+
+here="$PWD"
+status=1 # failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+    _cleanup_qemu
+    rm -f "$TEST_DIR/nbd"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.qemu
+
+_supported_fmt qcow2
+_supported_proto file # uses NBD as well
+_supported_os Linux
+
+function do_run_qemu()
+{
+    echo Testing: "$@"
+    $QEMU -nographic -qmp stdio -serial none "$@"
+    echo
+}
+
+function run_qemu()
+{
+    do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qmp \
+                          | _filter_qemu | _filter_imgfmt \
+                          | _filter_actual_image_size
+}
+
+echo
+echo "=== Create partially sparse image, then add dirty bitmap ==="
+echo
+
+_make_test_img 4M
+$QEMU_IO -c 'w -P 0x11 1M 2M' "$TEST_IMG" | _filter_qemu_io
+run_qemu <<EOF
+{ "execute": "qmp_capabilities" }
+{ "execute": "blockdev-add",
+  "arguments": {
+    "driver": "$IMGFMT",
+    "node-name": "n",
+    "file": {
+      "driver": "file",
+      "filename": "$TEST_IMG"
+    }
+  }
+}
+{ "execute": "block-dirty-bitmap-add",
+  "arguments": {
+    "node": "n",
+    "name": "b",
+    "persistent": true
+  }
+}
+{ "execute": "quit" }
+EOF
+
+echo
+echo "=== Write part of the file under active bitmap ==="
+echo
+
+$QEMU_IO -c 'w -P 0x22 2M 2M' "$TEST_IMG" | _filter_qemu_io
+
+echo
+echo "=== End dirty bitmap, and start serving image over NBD ==="
+echo
+
+_launch_qemu 2> >(_filter_nbd)
+
+silent=
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"qmp_capabilities"}' "return"
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"blockdev-add",
+  "arguments":{"driver":"qcow2", "node-name":"n",
+    "file":{"driver":"file", "filename":"'"$TEST_IMG"'"}}}' "return"
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"x-block-dirty-bitmap-disable",
+  "arguments":{"node":"n", "name":"b"}}' "return"
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-start",
+  "arguments":{"addr":{"type":"unix",
+    "data":{"path":"'"$TEST_DIR/nbd"'"}}}}' "return"
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-add",
+  "arguments":{"device":"n"}}' "return"
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"x-nbd-server-add-bitmap",
+  "arguments":{"name":"n", "bitmap":"b"}}' "return"
+
+echo
+echo "=== Contrast normal status with dirty-bitmap status ==="
+echo
+
+QEMU_IO_OPTIONS=$QEMU_IO_OPTIONS_NO_FMT
+IMG="driver=nbd,export=n,server.type=unix,server.path=$TEST_DIR/nbd"
+$QEMU_IO -r -c 'r -P 0 0 1m' -c 'r -P 0x11 1m 1m' \
+  -c 'r -P 0x22 2m 2m' --image-opts "$IMG" | _filter_qemu_io
+$QEMU_IMG map --output=json --image-opts \
+  "$IMG" | _filter_qemu_img_map
+$QEMU_IMG map --output=json --image-opts \
+  "$IMG,x-dirty-bitmap=qemu:dirty-bitmap:b" | _filter_qemu_img_map
+
+echo
+echo "=== End NBD server ==="
+echo
+
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-remove",
+  "arguments":{"name":"n"}}' "return"
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "return"
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"quit"}' "return"
+
+# success, all done
+echo '*** done'
+rm -f $seq.full
+status=0

tests/qemu-iotests/223.out

@@ -0,0 +1,49 @@
+QA output created by 223
+
+=== Create partially sparse image, then add dirty bitmap ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304
+wrote 2097152/2097152 bytes at offset 1048576
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Testing:
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+
+
+=== Write part of the file under active bitmap ===
+
+wrote 2097152/2097152 bytes at offset 2097152
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+=== End dirty bitmap, and start serving image over NBD ===
+
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+
+=== Contrast normal status with dirty-bitmap status ===
+
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 2097152/2097152 bytes at offset 2097152
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+[{ "start": 0, "length": 1048576, "depth": 0, "zero": true, "data": false},
+{ "start": 1048576, "length": 3145728, "depth": 0, "zero": false, "data": true}]
+[{ "start": 0, "length": 2097152, "depth": 0, "zero": false, "data": true},
+{ "start": 2097152, "length": 2097152, "depth": 0, "zero": false, "data": false}]
+
+=== End NBD server ===
+
+{"return": {}}
+{"return": {}}
+{"return": {}}
+*** done

tests/qemu-iotests/group

@@ -220,3 +220,5 @@
 218 rw auto quick
 219 rw auto
 221 rw auto quick
+222 rw auto quick
+223 rw auto quick