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PVE backup: backup-access api: simplify bitmap logic

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See inner patch for details.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2025-04-04 16:13:41 +02:00
parent 053f68a7ac
commit b30e898392
2 changed files with 207 additions and 0 deletions
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206
debian/patches/pve/0073-PVE-backup-backup-access-api-simplify-bitmap-logic.patch vendored Normal file
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@ -0,0 +1,206 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Fiona Ebner <f.ebner@proxmox.com>
Date: Fri, 4 Apr 2025 15:31:36 +0200
Subject: [PATCH] PVE backup: backup-access api: simplify bitmap logic
Currently, only one bitmap name per target is planned to be used.
Simply use the target ID itself as the bitmap name. This allows to
simplify the logic quite a bit and there also is no need for the
backup_access_bitmaps hash table anymore.
For the return value, the bitmap names are still passed along for
convenience in the caller.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Tested-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Reviewed-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
pve-backup.c | 72 ++++++++++++--------------------------------
qapi/block-core.json | 15 ++++-----
2 files changed, 26 insertions(+), 61 deletions(-)
diff --git a/pve-backup.c b/pve-backup.c
index 18bcf29533..0ea0343b22 100644
--- a/pve-backup.c
+++ b/pve-backup.c
@@ -74,7 +74,6 @@ static struct PVEBackupState {
CoMutex backup_mutex;
CoMutex dump_callback_mutex;
char *target_id;
- GHashTable *backup_access_bitmaps; // key=target_id, value=bitmap_name
} backup_state;
static void pvebackup_init(void)
@@ -106,7 +105,7 @@ typedef struct PVEBackupDevInfo {
PBSBitmapAction bitmap_action;
BlockDriverState *target;
BlockJob *job;
- char *requested_bitmap_name; // used by external backup access during initialization
+ BackupAccessSetupBitmapMode requested_bitmap_mode;
} PVEBackupDevInfo;
static void pvebackup_propagate_error(Error *err)
@@ -1043,16 +1042,7 @@ BackupAccessInfoList *coroutine_fn qmp_backup_access_setup(
error_propagate(errp, local_err);
goto err;
}
- if (it->value->bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_NONE) {
- di->bitmap_action = PBS_BITMAP_ACTION_NOT_USED;
- } else {
- di->requested_bitmap_name = g_strdup(it->value->bitmap_name);
- if (it->value->bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_NEW) {
- di->bitmap_action = PBS_BITMAP_ACTION_NEW;
- } else if (it->value->bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_USE) {
- di->bitmap_action = PBS_BITMAP_ACTION_USED;
- }
- }
+ di->requested_bitmap_mode = it->value->bitmap_mode;
di_list = g_list_append(di_list, di);
}
bdrv_graph_co_rdunlock();
@@ -1082,10 +1072,7 @@ BackupAccessInfoList *coroutine_fn qmp_backup_access_setup(
/* clear previous backup's bitmap_list */
clear_backup_state_bitmap_list();
- if (!backup_state.backup_access_bitmaps) {
- backup_state.backup_access_bitmaps =
- g_hash_table_new_full(g_str_hash, g_str_equal, free, free);
- }
+ const char *bitmap_name = target_id;
/* create bitmaps if requested */
l = di_list;
@@ -1098,59 +1085,43 @@ BackupAccessInfoList *coroutine_fn qmp_backup_access_setup(
PBSBitmapAction action = PBS_BITMAP_ACTION_NOT_USED;
size_t dirty = di->size;
- const char *old_bitmap_name =
- (const char*)g_hash_table_lookup(backup_state.backup_access_bitmaps, target_id);
-
- bool same_bitmap_name = old_bitmap_name
- && di->requested_bitmap_name
- && strcmp(di->requested_bitmap_name, old_bitmap_name) == 0;
-
- /* special case: if we explicitly requested a *new* bitmap, treat an
- * existing bitmap as having a different name */
- if (di->bitmap_action == PBS_BITMAP_ACTION_NEW) {
- same_bitmap_name = false;
- }
-
- if (old_bitmap_name && !same_bitmap_name) {
- BdrvDirtyBitmap *old_bitmap = bdrv_find_dirty_bitmap(di->bs, old_bitmap_name);
- if (!old_bitmap) {
- warn_report("setup backup access: expected old bitmap '%s' not found for drive "
- "'%s'", old_bitmap_name, di->device_name);
- } else {
- g_hash_table_remove(backup_state.backup_access_bitmaps, target_id);
+ if (di->requested_bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_NONE ||
+ di->requested_bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_NEW) {
+ BdrvDirtyBitmap *old_bitmap = bdrv_find_dirty_bitmap(di->bs, bitmap_name);
+ if (old_bitmap) {
bdrv_release_dirty_bitmap(old_bitmap);
- action = PBS_BITMAP_ACTION_NOT_USED_REMOVED;
+ action = PBS_BITMAP_ACTION_NOT_USED_REMOVED; // set below for new
}
}
BdrvDirtyBitmap *bitmap = NULL;
- if (di->requested_bitmap_name) {
- bitmap = bdrv_find_dirty_bitmap(di->bs, di->requested_bitmap_name);
+ if (di->requested_bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_NEW ||
+ di->requested_bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_USE) {
+ bitmap = bdrv_find_dirty_bitmap(di->bs, bitmap_name);
if (!bitmap) {
bitmap = bdrv_create_dirty_bitmap(di->bs, PROXMOX_BACKUP_DEFAULT_CHUNK_SIZE,
- di->requested_bitmap_name, errp);
+ bitmap_name, errp);
if (!bitmap) {
qemu_mutex_unlock(&backup_state.stat.lock);
goto err;
}
bdrv_set_dirty_bitmap(bitmap, 0, di->size);
- if (same_bitmap_name) {
+ if (di->requested_bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_USE) {
action = PBS_BITMAP_ACTION_MISSING_RECREATED;
} else {
action = PBS_BITMAP_ACTION_NEW;
}
} else {
+ if (di->requested_bitmap_mode == BACKUP_ACCESS_SETUP_BITMAP_MODE_NEW) {
+ qemu_mutex_unlock(&backup_state.stat.lock);
+ error_setg(errp, "internal error - removed old bitmap still present");
+ goto err;
+ }
/* track clean chunks as reused */
dirty = MIN(bdrv_get_dirty_count(bitmap), di->size);
backup_state.stat.reused += di->size - dirty;
action = PBS_BITMAP_ACTION_USED;
}
-
- if (!same_bitmap_name) {
- g_hash_table_insert(backup_state.backup_access_bitmaps,
- strdup(target_id), strdup(di->requested_bitmap_name));
- }
-
}
PBSBitmapInfo *info = g_malloc(sizeof(*info));
@@ -1207,9 +1178,9 @@ BackupAccessInfoList *coroutine_fn qmp_backup_access_setup(
info->value->node_name = g_strdup(bdrv_get_node_name(di->fleecing.snapshot_access));
info->value->device = g_strdup(di->device_name);
info->value->size = di->size;
- if (di->requested_bitmap_name) {
+ if (di->bitmap) {
info->value->bitmap_node_name = g_strdup(bdrv_get_node_name(di->bs));
- info->value->bitmap_name = g_strdup(di->requested_bitmap_name);
+ info->value->bitmap_name = g_strdup(bitmap_name);
info->value->bitmap_action = di->bitmap_action;
info->value->has_bitmap_action = true;
}
@@ -1274,9 +1245,6 @@ void backup_access_teardown(bool success)
g_free(di->device_name);
di->device_name = NULL;
- g_free(di->requested_bitmap_name);
- di->requested_bitmap_name = NULL;
-
g_free(di);
}
g_list_free(backup_state.di_list);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 09beb3217c..02c043f0f7 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1140,18 +1140,12 @@
#
# @device: the block device name.
#
-# @bitmap-name: use/create a bitmap with this name for the device. Re-using the
-# same name allows for making incremental backups. Check the @bitmap-action
-# in the result to see if you can actually re-use the bitmap or if it had to
-# be newly created.
-#
# @bitmap-mode: used to control whether the bitmap should be reused or
-# recreated.
+# recreated or not used. Default is not using a bitmap.
#
##
{ 'struct': 'BackupAccessSourceDevice',
- 'data': { 'device': 'str', '*bitmap-name': 'str',
- '*bitmap-mode': 'BackupAccessSetupBitmapMode' } }
+ 'data': { 'device': 'str', '*bitmap-mode': 'BackupAccessSetupBitmapMode' } }
##
# @BackupAccessSetupBitmapMode:
@@ -1175,7 +1169,10 @@
#
# @target-id: the unique ID of the backup target.
#
-# @devices: list of devices for which to create the backup access.
+# @devices: list of devices for which to create the backup access. Also
+# controls whether to use/create a bitmap for the device. Check the
+# @bitmap-action in the result to see what action was actually taken for the
+# bitmap. Each target controls its own bitmaps.
#
# Returns: a list of @BackupAccessInfo, one for each device.
#

1
debian/patches/series vendored
View File

@ -87,3 +87,4 @@ pve/0069-PVE-backup-factor-out-get_single_device_info-helper.patch
pve/0070-PVE-backup-implement-bitmap-support-for-external-bac.patch
pve/0071-PVE-backup-backup-access-api-indicate-situation-wher.patch
pve/0072-PVE-backup-backup-access-api-explicit-bitmap-mode-pa.patch
pve/0073-PVE-backup-backup-access-api-simplify-bitmap-logic.patch