From ae0be0a7cbfb291c640b25d31013f938745e8c08 Mon Sep 17 00:00:00 2001

Message-Id: <ae0be0a7cbfb291c640b25d31013f938745e8c08@dist-git>

From: Peter Krempa <pkrempa@redhat.com>

Date: Tue, 23 Jun 2020 12:24:00 +0200

Subject: [PATCH] qemu: Rewrite bitmap handling for block commit

MIME-Version: 1.0

Content-Type: text/plain; charset=UTF-8

Content-Transfer-Encoding: 8bit

Reuse qemuBlockGetBitmapMergeActions which allows removing the ad-hoc

implementation of bitmap merging for block commit. The new approach is

way simpler and more robust and also allows us to get rid of the

disabling of bitmaps done prior to the start as we actually do want to

update the bitmaps in the base.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>

Reviewed-by: Eric Blake <eblake@redhat.com>

(cherry picked from commit 20a7abc2d2d8a378103abf105fa0c617218ec023)

https://bugzilla.redhat.com/show_bug.cgi?id=1804593

Message-Id: <2b1054dbe576d3984c960a42d175edbafa92565a.1592906423.git.pkrempa@redhat.com>

Reviewed-by: Ján Tomko <jtomko@redhat.com>

---

 src/qemu/qemu_block.c                         | 203 +-----------------

 src/qemu/qemu_block.h                         |  11 +-

 src/qemu/qemu_blockjob.c                      |  25 ++-

 src/qemu/qemu_driver.c                        |  56 +----

 tests/qemublocktest.c                         |  18 +-

 .../qemublocktestdata/bitmapblockcommit/empty |   1 -

 6 files changed, 42 insertions(+), 272 deletions(-)

diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c

index b2296c2b4c..ff9e000461 100644

--- a/src/qemu/qemu_block.c

+++ b/src/qemu/qemu_block.c

@@ -3194,117 +3194,7 @@ qemuBlockBitmapsHandleBlockcopy(virStorageSourcePtr src,

 /**

  * @topsrc: virStorageSource representing 'top' of the job

  * @basesrc: virStorageSource representing 'base' of the job

- * @blockNamedNodeData: hash table containing data about bitmaps

- * @actions: filled with arguments for a 'transaction' command

- * @disabledBitmapsBase: filled with a list of bitmap names which must be disabled

- *

- * Prepares data for correctly handling bitmaps during the start of a commit

- * job. The bitmaps in the 'base' image must be disabled, so that the writes

- * done by the blockjob don't dirty the enabled bitmaps.

- *

- * @actions and @disabledBitmapsBase are untouched if no bitmaps need

- * to be disabled.

- */

-int

-qemuBlockBitmapsHandleCommitStart(virStorageSourcePtr topsrc,

-                                  virStorageSourcePtr basesrc,

-                                  virHashTablePtr blockNamedNodeData,

-                                  virJSONValuePtr *actions,

-                                  char ***disabledBitmapsBase)

-{

-    g_autoptr(virJSONValue) act = virJSONValueNewArray();

-    VIR_AUTOSTRINGLIST bitmaplist = NULL;

-    size_t curbitmapstr = 0;

-    qemuBlockNamedNodeDataPtr entry;

-    bool disable_bitmaps = false;

-    size_t i;

-

-    if (!(entry = virHashLookup(blockNamedNodeData, basesrc->nodeformat)))

-        return 0;

-

-    bitmaplist = g_new0(char *, entry->nbitmaps + 1);

-

-    for (i = 0; i < entry->nbitmaps; i++) {

-        qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i];

-

-        if (!bitmap->recording || bitmap->inconsistent ||

-            !qemuBlockBitmapChainIsValid(topsrc, bitmap->name, blockNamedNodeData))

-            continue;

-

-        disable_bitmaps = true;

-

-        if (qemuMonitorTransactionBitmapDisable(act, basesrc->nodeformat,

-                                                bitmap->name) < 0)

-            return -1;

-

-        bitmaplist[curbitmapstr++] = g_strdup(bitmap->name);

-    }

-

-    if (disable_bitmaps) {

-        *actions = g_steal_pointer(&act;;

-        *disabledBitmapsBase = g_steal_pointer(&bitmaplist);

-    }

-

-    return 0;

-}

-

-

-struct qemuBlockBitmapsHandleCommitData {

-    bool skip;

-    bool create;

-    bool enable;

-    const char *basenode;

-    virJSONValuePtr merge;

-    unsigned long long granularity;

-    bool persistent;

-};

-

-

-static void

-qemuBlockBitmapsHandleCommitDataFree(void *opaque)

-{

-    struct qemuBlockBitmapsHandleCommitData *data = opaque;

-

-    virJSONValueFree(data->merge);

-    g_free(data);

-}

-

-

-static int

-qemuBlockBitmapsHandleCommitFinishIterate(void *payload,

-                                          const void *entryname,

-                                          void *opaque)

-{

-    struct qemuBlockBitmapsHandleCommitData *data = payload;

-    const char *bitmapname = entryname;

-    virJSONValuePtr actions = opaque;

-

-    if (data->skip)

-        return 0;

-

-    if (data->create) {

-        if (qemuMonitorTransactionBitmapAdd(actions, data->basenode, bitmapname,

-                                            data->persistent, !data->enable,

-                                            data->granularity) < 0)

-            return -1;

-    } else {

-        if (data->enable &&

-            qemuMonitorTransactionBitmapEnable(actions, data->basenode, bitmapname) < 0)

-            return -1;

-    }

-

-    if (data->merge &&

-        qemuMonitorTransactionBitmapMerge(actions, data->basenode, bitmapname,

-                                          &data->merge) < 0)

-        return -1;

-

-    return 0;

-}

-

-

-/**

- * @topsrc: virStorageSource representing 'top' of the job

- * @basesrc: virStorageSource representing 'base' of the job

+ * @active: commit job is an active layer block-commit

  * @blockNamedNodeData: hash table containing data about bitmaps

  * @actions: filled with arguments for a 'transaction' command

  * @disabledBitmapsBase: bitmap names which were disabled

@@ -3317,95 +3207,20 @@ qemuBlockBitmapsHandleCommitFinishIterate(void *payload,

 int

 qemuBlockBitmapsHandleCommitFinish(virStorageSourcePtr topsrc,

                                    virStorageSourcePtr basesrc,

+                                   bool active,

                                    virHashTablePtr blockNamedNodeData,

-                                   virJSONValuePtr *actions,

-                                   char **disabledBitmapsBase)

+                                   virJSONValuePtr *actions)

 {

-    g_autoptr(virJSONValue) act = virJSONValueNewArray();

-    virStorageSourcePtr n;

-    qemuBlockNamedNodeDataPtr entry;

-    g_autoptr(virHashTable) commitdata = NULL;

-    struct qemuBlockBitmapsHandleCommitData *bitmapdata;

-    size_t i;

-

-    commitdata = virHashNew(qemuBlockBitmapsHandleCommitDataFree);

-

-    for (n = topsrc; n != basesrc; n = n->backingStore) {

-        if (!(entry = virHashLookup(blockNamedNodeData, n->nodeformat)))

-            continue;

-

-        for (i = 0; i < entry->nbitmaps; i++) {

-            qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i];

-

-            if (!(bitmapdata = virHashLookup(commitdata, bitmap->name))) {

-                bitmapdata = g_new0(struct qemuBlockBitmapsHandleCommitData, 1);

+    virStorageSourcePtr writebitmapsrc = NULL;

-                /* we must mirror the state of the topmost bitmap and merge

-                 * everything else */

-                bitmapdata->create = true;

-                bitmapdata->enable = bitmap->recording;

-                bitmapdata->basenode = basesrc->nodeformat;

-                bitmapdata->merge = virJSONValueNewArray();

-                bitmapdata->granularity = bitmap->granularity;

-                bitmapdata->persistent = bitmap->persistent;

+    if (active)

+        writebitmapsrc = basesrc;

-                if (virHashAddEntry(commitdata, bitmap->name, bitmapdata) < 0) {

-                    qemuBlockBitmapsHandleCommitDataFree(bitmapdata);

-                    return -1;

-                }

-            }

-

-            if (bitmap->inconsistent ||

-                !qemuBlockBitmapChainIsValid(topsrc, bitmap->name, blockNamedNodeData))

-                bitmapdata->skip = true;

-

-            if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(bitmapdata->merge,

-                                                                 n->nodeformat,

-                                                                 bitmap->name) < 0)

-                return -1;

-        }

-    }

-

-    if ((entry = virHashLookup(blockNamedNodeData, basesrc->nodeformat))) {

-        /* note that all bitmaps in 'base' were disabled when commit was started */

-        for (i = 0; i < entry->nbitmaps; i++) {

-            qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i];

-

-            if ((bitmapdata = virHashLookup(commitdata, bitmap->name))) {

-                bitmapdata->create = false;

-            } else {

-                if (disabledBitmapsBase) {

-                    char **disabledbitmaps;

-

-                    for (disabledbitmaps = disabledBitmapsBase; *disabledbitmaps; disabledbitmaps++) {

-                        if (STREQ(*disabledbitmaps, bitmap->name)) {

-                            bitmapdata = g_new0(struct qemuBlockBitmapsHandleCommitData, 1);

-

-                            bitmapdata->create = false;

-                            bitmapdata->enable = true;

-                            bitmapdata->basenode = basesrc->nodeformat;

-                            bitmapdata->granularity = bitmap->granularity;

-                            bitmapdata->persistent = bitmap->persistent;

-

-                            if (virHashAddEntry(commitdata, bitmap->name, bitmapdata) < 0) {

-                                qemuBlockBitmapsHandleCommitDataFree(bitmapdata);

-                                return -1;

-                            }

-

-                            break;

-                        }

-                    }

-                }

-            }

-        }

-    }

-

-    if (virHashForEach(commitdata, qemuBlockBitmapsHandleCommitFinishIterate, act) < 0)

+    if (qemuBlockGetBitmapMergeActions(topsrc, basesrc, basesrc, NULL, NULL,

+                                       writebitmapsrc, actions,

+                                       blockNamedNodeData) < 0)

         return -1;

-    if (virJSONValueArraySize(act) > 0)

-        *actions = g_steal_pointer(&act;;

-

     return 0;

 }

diff --git a/src/qemu/qemu_block.h b/src/qemu/qemu_block.h

index 2500390734..19d2fc32e0 100644

--- a/src/qemu/qemu_block.h

+++ b/src/qemu/qemu_block.h

@@ -243,19 +243,12 @@ qemuBlockBitmapsHandleBlockcopy(virStorageSourcePtr src,

                                 bool shallow,

                                 virJSONValuePtr *actions);

-int

-qemuBlockBitmapsHandleCommitStart(virStorageSourcePtr topsrc,

-                                  virStorageSourcePtr basesrc,

-                                  virHashTablePtr blockNamedNodeData,

-                                  virJSONValuePtr *actions,

-                                  char ***disabledBitmapsBase);

-

 int

 qemuBlockBitmapsHandleCommitFinish(virStorageSourcePtr topsrc,

                                    virStorageSourcePtr basesrc,

+                                   bool active,

                                    virHashTablePtr blockNamedNodeData,

-                                   virJSONValuePtr *actions,

-                                   char **disabledBitmapsBase);

+                                   virJSONValuePtr *actions);

 int

 qemuBlockReopenReadWrite(virDomainObjPtr vm,

diff --git a/src/qemu/qemu_blockjob.c b/src/qemu/qemu_blockjob.c

index c80c71295b..c63a691a0e 100644

--- a/src/qemu/qemu_blockjob.c

+++ b/src/qemu/qemu_blockjob.c

@@ -1063,6 +1063,7 @@ qemuBlockJobProcessEventCompletedCommitBitmaps(virDomainObjPtr vm,

     qemuDomainObjPrivatePtr priv = vm->privateData;

     g_autoptr(virHashTable) blockNamedNodeData = NULL;

     g_autoptr(virJSONValue) actions = NULL;

+    bool active = job->type == QEMU_BLOCKJOB_TYPE_ACTIVE_COMMIT;

     if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV_REOPEN))

         return 0;

@@ -1072,16 +1073,18 @@ qemuBlockJobProcessEventCompletedCommitBitmaps(virDomainObjPtr vm,

     if (qemuBlockBitmapsHandleCommitFinish(job->data.commit.top,

                                            job->data.commit.base,

+                                           active,

                                            blockNamedNodeData,

-                                           &actions,

-                                           job->data.commit.disabledBitmapsBase) < 0)

+                                           &actions) < 0)

         return 0;

     if (!actions)

         return 0;

-    if (qemuBlockReopenReadWrite(vm, job->data.commit.base, asyncJob) < 0)

-        return -1;

+    if (!active) {

+        if (qemuBlockReopenReadWrite(vm, job->data.commit.base, asyncJob) < 0)

+            return -1;

+    }

     if (qemuDomainObjEnterMonitorAsync(priv->driver, vm, asyncJob) < 0)

         return -1;

@@ -1091,8 +1094,10 @@ qemuBlockJobProcessEventCompletedCommitBitmaps(virDomainObjPtr vm,

     if (qemuDomainObjExitMonitor(priv->driver, vm) < 0)

         return -1;

-    if (qemuBlockReopenReadOnly(vm, job->data.commit.base, asyncJob) < 0)

-        return -1;

+    if (!active) {

+        if (qemuBlockReopenReadOnly(vm, job->data.commit.base, asyncJob) < 0)

+            return -1;

+    }

     return 0;

 }

@@ -1262,6 +1267,9 @@ qemuBlockJobProcessEventCompletedActiveCommit(virQEMUDriverPtr driver,

     job->disk->src = job->data.commit.base;

     job->disk->src->readonly = job->data.commit.top->readonly;

+    if (qemuBlockJobProcessEventCompletedCommitBitmaps(vm, job, asyncJob) < 0)

+        return;

+

     qemuBlockJobEventProcessConcludedRemoveChain(driver, vm, asyncJob, job->data.commit.top);

     if (job->data.commit.deleteCommittedImages)

@@ -1333,6 +1341,7 @@ qemuBlockJobProcessEventFailedActiveCommit(virQEMUDriverPtr driver,

                                            virDomainObjPtr vm,

                                            qemuBlockJobDataPtr job)

 {

+    g_autoptr(virJSONValue) actions = virJSONValueNewArray();

     virDomainDiskDefPtr disk = job->disk;

     VIR_DEBUG("active commit job '%s' on VM '%s' failed", job->name, vm->def->name);

@@ -1340,6 +1349,10 @@ qemuBlockJobProcessEventFailedActiveCommit(virQEMUDriverPtr driver,

     if (!disk)

         return;

+    ignore_value(qemuMonitorTransactionBitmapRemove(actions, disk->mirror->nodeformat,

+                                                    "libvirt-tmp-activewrite"));

+

+

     /* Ideally, we would make the backing chain read only again (yes, SELinux

      * can do that using different labels). But that is not implemented yet and

      * not leaking security driver metadata is more important. */

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c

index 9f7d96c0b6..983d4a04a8 100644

--- a/src/qemu/qemu_driver.c

+++ b/src/qemu/qemu_driver.c

@@ -17594,9 +17594,9 @@ qemuDomainBlockPivot(virQEMUDriverPtr driver,

     case QEMU_BLOCKJOB_TYPE_COPY:

         if (blockdev && !job->jobflagsmissing) {

-            g_autoptr(virHashTable) blockNamedNodeData = NULL;

             bool shallow = job->jobflags & VIR_DOMAIN_BLOCK_COPY_SHALLOW;

             bool reuse = job->jobflags & VIR_DOMAIN_BLOCK_COPY_REUSE_EXT;

+            g_autoptr(virHashTable) blockNamedNodeData = NULL;

             if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_NONE)))

                 return -1;

@@ -17634,16 +17634,15 @@ qemuDomainBlockPivot(virQEMUDriverPtr driver,

          * the bitmaps if it wasn't present thus must skip this */

         if (blockdev &&

             virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV_REOPEN)) {

-            g_autoptr(virHashTable) blockNamedNodeData = NULL;

-            if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_NONE)))

-                return -1;

+            actions = virJSONValueNewArray();

-            if (qemuBlockBitmapsHandleCommitFinish(job->data.commit.top,

-                                                   job->data.commit.base,

-                                                   blockNamedNodeData,

-                                                   &actions,

-                                                   job->data.commit.disabledBitmapsBase) < 0)

+            if (qemuMonitorTransactionBitmapAdd(actions,

+                                                job->data.commit.base->nodeformat,

+                                                "libvirt-tmp-activewrite",

+                                                false,

+                                                false,

+                                                0) < 0)

                 return -1;

         }

@@ -18758,7 +18757,6 @@ qemuDomainBlockCommit(virDomainPtr dom,

     const char *nodebase = NULL;

     bool persistjob = false;

     bool blockdev = false;

-    g_autoptr(virJSONValue) bitmapDisableActions = NULL;

     VIR_AUTOSTRINGLIST bitmapDisableList = NULL;

     virCheckFlags(VIR_DOMAIN_BLOCK_COMMIT_SHALLOW |

@@ -18920,27 +18918,6 @@ qemuDomainBlockCommit(virDomainPtr dom,

             goto endjob;

     }

-    if (blockdev &&

-        virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV_REOPEN)) {

-        g_autoptr(virHashTable) blockNamedNodeData = NULL;

-        if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_NONE)))

-            goto endjob;

-

-        if (qemuBlockBitmapsHandleCommitStart(topSource, baseSource,

-                                              blockNamedNodeData,

-                                              &bitmapDisableActions,

-                                              &bitmapDisableList) < 0)

-            goto endjob;

-

-        /* if we don't have terminator on 'base' we can't reopen it */

-        if (bitmapDisableActions && !baseSource->backingStore) {

-            virReportError(VIR_ERR_OPERATION_UNSUPPORTED,

-                           _("can't handle bitmaps on unterminated backing image '%s'"),

-                           base);

-            goto endjob;

-        }

-    }

-

     if (!(job = qemuBlockJobDiskNewCommit(vm, disk, top_parent, topSource,

                                           baseSource, &bitmapDisableList,

                                           flags & VIR_DOMAIN_BLOCK_COMMIT_DELETE,

@@ -18965,23 +18942,6 @@ qemuDomainBlockCommit(virDomainPtr dom,

             !(backingPath = qemuBlockGetBackingStoreString(baseSource, false)))

             goto endjob;

-        if (bitmapDisableActions) {

-            int rc;

-

-            if (qemuBlockReopenReadWrite(vm, baseSource, QEMU_ASYNC_JOB_NONE) < 0)

-                goto endjob;

-

-            qemuDomainObjEnterMonitor(driver, vm);

-            rc = qemuMonitorTransaction(priv->mon, &bitmapDisableActions);

-            if (qemuDomainObjExitMonitor(driver, vm) < 0)

-                goto endjob;

-

-            if (qemuBlockReopenReadOnly(vm, baseSource, QEMU_ASYNC_JOB_NONE) < 0)

-                goto endjob;

-

-            if (rc < 0)

-                goto endjob;

-        }

     } else {

         device = job->name;

     }

diff --git a/tests/qemublocktest.c b/tests/qemublocktest.c

index 8ce878f15b..f0e80a0738 100644

--- a/tests/qemublocktest.c

+++ b/tests/qemublocktest.c

@@ -928,12 +928,11 @@ testQemuBlockBitmapBlockcommit(const void *opaque)

     g_autofree char *actual = NULL;

     g_autofree char *expectpath = NULL;

-    g_autoptr(virJSONValue) actionsDisable = NULL;

     g_autoptr(virJSONValue) actionsMerge = NULL;

     g_autoptr(virJSONValue) nodedatajson = NULL;

     g_autoptr(virHashTable) nodedata = NULL;

     g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;

-    VIR_AUTOSTRINGLIST bitmapsDisable = NULL;

+    bool active = data->top == data->chain;

     expectpath = g_strdup_printf("%s/%s%s", abs_srcdir,

                                  blockcommitPrefix, data->name);

@@ -947,20 +946,10 @@ testQemuBlockBitmapBlockcommit(const void *opaque)

         return -1;

     }

-    if (qemuBlockBitmapsHandleCommitStart(data->top, data->base, nodedata,

-                                          &actionsDisable, &bitmapsDisable) < 0)

-        return -1;

-

-    virBufferAddLit(&buf, "pre job bitmap disable:\n");

-

-    if (actionsDisable &&

-        virJSONValueToBuffer(actionsDisable, &buf, true) < 0)

-        return -1;

-

     virBufferAddLit(&buf, "merge bitmpas:\n");

-    if (qemuBlockBitmapsHandleCommitFinish(data->top, data->base, nodedata,

-                                           &actionsMerge, bitmapsDisable) < 0)

+    if (qemuBlockBitmapsHandleCommitFinish(data->top, data->base, active, nodedata,

+                                           &actionsMerge) < 0)

         return -1;

     if (actionsMerge &&

@@ -1356,6 +1345,7 @@ mymain(void)

 #define TEST_BITMAP_BLOCKCOMMIT(testname, topimg, baseimg, ndf) \

     do {\

         blockbitmapblockcommitdata.name = testname; \

+        blockbitmapblockcommitdata.chain = bitmapSourceChain; \

         blockbitmapblockcommitdata.top = testQemuBitmapGetFakeChainEntry(bitmapSourceChain, topimg); \

         blockbitmapblockcommitdata.base = testQemuBitmapGetFakeChainEntry(bitmapSourceChain, baseimg); \

         blockbitmapblockcommitdata.nodedatafile = ndf; \

diff --git a/tests/qemublocktestdata/bitmapblockcommit/empty b/tests/qemublocktestdata/bitmapblockcommit/empty

index bfc58f994e..9260011852 100644

--- a/tests/qemublocktestdata/bitmapblockcommit/empty

+++ b/tests/qemublocktestdata/bitmapblockcommit/empty

@@ -1,2 +1 @@

-pre job bitmap disable:

 merge bitmpas:

-- 

2.27.0