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apply dirty-bitmap state migration + fix

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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2020-10-29 18:05:43 +01:00
parent 72ae34ecce
commit d95ad93eed
3 changed files with 226 additions and 0 deletions
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33
debian/patches/pve/0054-migration-block-dirty-bitmap-fix-larger-granularity-.patch vendored Normal file
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@ -0,0 +1,33 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Reiter <s.reiter@proxmox.com>
Date: Thu, 22 Oct 2020 17:34:17 +0200
Subject: [PATCH] migration/block-dirty-bitmap: fix larger granularity bitmaps
sectors_per_chunk is a 64 bit integer, but the calculation would be done
in 32 bits, leading to an overflow for coarse bitmap granularities.
If that results in the value 0, it leads to a hang where no progress is
made but send_bitmap_bits is constantly called with nr_sectors being 0.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
migration/block-dirty-bitmap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
index 784330ebe1..5bf0d9fbc6 100644
--- a/migration/block-dirty-bitmap.c
+++ b/migration/block-dirty-bitmap.c
@@ -334,8 +334,9 @@ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
dbms->node_name = bs_name;
dbms->bitmap = bitmap;
dbms->total_sectors = bdrv_nb_sectors(bs);
- dbms->sectors_per_chunk = CHUNK_SIZE * 8 *
+ dbms->sectors_per_chunk = CHUNK_SIZE * 8LLU *
bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
+ assert(dbms->sectors_per_chunk != 0);
if (bdrv_dirty_bitmap_enabled(bitmap)) {
dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_ENABLED;
}

191
debian/patches/pve/0055-PVE-Migrate-dirty-bitmap-state-via-savevm.patch vendored Normal file
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@ -0,0 +1,191 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Reiter <s.reiter@proxmox.com>
Date: Thu, 22 Oct 2020 17:34:18 +0200
Subject: [PATCH] PVE: Migrate dirty bitmap state via savevm
QEMU provides 'savevm' registrations as a mechanism for arbitrary state
to be migrated along with a VM. Use this to send a serialized version of
dirty bitmap state data from proxmox-backup-qemu, and restore it on the
target node.
Also add a flag to query-proxmox-support so qemu-server can determine if
safe migration is possible and makes sense.
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
include/migration/misc.h | 3 ++
migration/Makefile.objs | 1 +
migration/pbs-state.c | 92 ++++++++++++++++++++++++++++++++++++++++
pve-backup.c | 1 +
qapi/block-core.json | 9 +++-
softmmu/vl.c | 1 +
6 files changed, 106 insertions(+), 1 deletion(-)
create mode 100644 migration/pbs-state.c
diff --git a/include/migration/misc.h b/include/migration/misc.h
index 34e7d75713..f83816dd3c 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -75,4 +75,7 @@ bool migration_in_incoming_postcopy(void);
/* migration/block-dirty-bitmap.c */
void dirty_bitmap_mig_init(void);
+/* migration/pbs-state.c */
+void pbs_state_mig_init(void);
+
#endif
diff --git a/migration/Makefile.objs b/migration/Makefile.objs
index 0fc619e380..20b3792599 100644
--- a/migration/Makefile.objs
+++ b/migration/Makefile.objs
@@ -9,6 +9,7 @@ common-obj-y += qjson.o
common-obj-y += block-dirty-bitmap.o
common-obj-y += multifd.o
common-obj-y += multifd-zlib.o
+common-obj-y += pbs-state.o
common-obj-$(CONFIG_ZSTD) += multifd-zstd.o
common-obj-$(CONFIG_RDMA) += rdma.o
diff --git a/migration/pbs-state.c b/migration/pbs-state.c
new file mode 100644
index 0000000000..165895b488
--- /dev/null
+++ b/migration/pbs-state.c
@@ -0,0 +1,92 @@
+/*
+ * PBS (dirty-bitmap) state migration
+ */
+
+#include "qemu/osdep.h"
+#include "migration/misc.h"
+#include "qemu-file.h"
+#include "migration/vmstate.h"
+#include "migration/register.h"
+#include "proxmox-backup-qemu.h"
+
+static void pbs_state_save_pending(QEMUFile *f, void *opaque,
+ uint64_t max_size,
+ uint64_t *res_precopy_only,
+ uint64_t *res_compatible,
+ uint64_t *res_postcopy_only)
+{
+ /* we send everything in save_setup, so nothing is ever pending */
+ *res_precopy_only = 0;
+ *res_compatible = 0;
+ *res_postcopy_only = 0;
+}
+
+/* receive PBS state via f and deserialize, called on target */
+static int pbs_state_load(QEMUFile *f, void *opaque, int version_id)
+{
+ /* safe cast, we cannot migrate to target with less bits than source */
+ size_t buf_size = (size_t)qemu_get_be64(f);
+
+ uint8_t *buf = (uint8_t *)malloc(buf_size);
+ size_t read = qemu_get_buffer(f, buf, buf_size);
+
+ if (read < buf_size) {
+ fprintf(stderr, "error receiving PBS state: not enough data\n");
+ return -EIO;
+ }
+
+ proxmox_import_state(buf, buf_size);
+
+ free(buf);
+ return 0;
+}
+
+/* serialize PBS state and send to target via f, called on source */
+static int pbs_state_save_setup(QEMUFile *f, void *opaque)
+{
+ size_t buf_size;
+ uint8_t *buf = proxmox_export_state(&buf_size);
+
+ /* LV encoding */
+ qemu_put_be64(f, buf_size);
+ qemu_put_buffer(f, buf, buf_size);
+
+ proxmox_free_state_buf(buf);
+ return 0;
+}
+
+static bool pbs_state_is_active(void *opaque)
+{
+ /* always active, i.e. we do our job for every migration, since there's no
+ * harm done if we just copy an empty buffer */
+ return true;
+}
+
+static bool pbs_state_is_active_iterate(void *opaque)
+{
+ /* we don't iterate, everything is sent in save_setup */
+ return false;
+}
+
+static bool pbs_state_has_postcopy(void *opaque)
+{
+ /* PBS state can't change during a migration (since that's blocking any
+ * potential backups), so we can copy everything before the VM is stopped */
+ return false;
+}
+
+static SaveVMHandlers savevm_pbs_state_handlers = {
+ .save_setup = pbs_state_save_setup,
+ .has_postcopy = pbs_state_has_postcopy,
+ .save_live_pending = pbs_state_save_pending,
+ .is_active_iterate = pbs_state_is_active_iterate,
+ .load_state = pbs_state_load,
+ .is_active = pbs_state_is_active,
+};
+
+void pbs_state_mig_init(void)
+{
+ register_savevm_live("pbs-state", 0, 1,
+ &savevm_pbs_state_handlers,
+ NULL);
+}
diff --git a/pve-backup.c b/pve-backup.c
index 1a2647e7a5..c12ff8bb61 100644
--- a/pve-backup.c
+++ b/pve-backup.c
@@ -1129,5 +1129,6 @@ ProxmoxSupportStatus *qmp_query_proxmox_support(Error **errp)
ProxmoxSupportStatus *ret = g_malloc0(sizeof(*ret));
ret->pbs_dirty_bitmap = true;
ret->query_bitmap_info = true;
+ ret->pbs_dirty_bitmap_migration = true;
return ret;
}
diff --git a/qapi/block-core.json b/qapi/block-core.json
index b31ad8d989..00c9e12fcc 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -890,9 +890,16 @@
#
# @query-bitmap-info: True if the 'query-pbs-bitmap-info' QMP call is supported.
#
+# @pbs-dirty-bitmap-migration: True if safe migration of dirty-bitmaps including
+# PBS state is supported. Enabling 'dirty-bitmaps'
+# migration cap if this is false/unset may lead
+# to crashes on migration!
+#
##
{ 'struct': 'ProxmoxSupportStatus',
- 'data': { 'pbs-dirty-bitmap': 'bool', 'query-bitmap-info': 'bool' } }
+ 'data': { 'pbs-dirty-bitmap': 'bool',
+ 'query-bitmap-info': 'bool',
+ 'pbs-dirty-bitmap-migration': 'bool' } }
##
# @query-proxmox-support:
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 16aa2186b0..88b13871fd 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -4288,6 +4288,7 @@ void qemu_init(int argc, char **argv, char **envp)
blk_mig_init();
ram_mig_init();
dirty_bitmap_mig_init();
+ pbs_state_mig_init();
qemu_opts_foreach(qemu_find_opts("mon"),
mon_init_func, NULL, &error_fatal);

2
debian/patches/series vendored
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@ -54,3 +54,5 @@ pve/0050-PVE-Add-sequential-job-transaction-support.patch
pve/0051-PVE-Backup-Use-a-transaction-to-synchronize-job-stat.patch
pve/0052-PVE-Backup-Use-more-coroutines-and-don-t-block-on-fi.patch
pve/0053-PVE-fix-and-clean-up-error-handling-for-create_backu.patch
pve/0054-migration-block-dirty-bitmap-fix-larger-granularity-.patch
pve/0055-PVE-Migrate-dirty-bitmap-state-via-savevm.patch