When running snapshot operations, there are various rules for which blockdevs are included/excluded. While this provides reasonable default behaviour, there are scenarios that are not well handled by the default logic. Some of the conditions do not have a single correct answer.
Thus there needs to be a way for the mgmt app to provide an explicit list of blockdevs to perform snapshots across. This can be achieved by passing a list of node names that should be used. Signed-off-by: Daniel P. Berrangé <berra...@redhat.com> --- block/monitor/block-hmp-cmds.c | 4 +-- block/snapshot.c | 48 ++++++++++++++++++++++------------ include/block/snapshot.h | 13 ++++----- migration/savevm.c | 16 ++++++------ monitor/hmp-cmds.c | 2 +- 5 files changed, 49 insertions(+), 34 deletions(-) diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c index 9df11494d6..db76c43cc2 100644 --- a/block/monitor/block-hmp-cmds.c +++ b/block/monitor/block-hmp-cmds.c @@ -900,7 +900,7 @@ void hmp_info_snapshots(Monitor *mon, const QDict *qdict) SnapshotEntry *snapshot_entry; Error *err = NULL; - bs = bdrv_all_find_vmstate_bs(&err); + bs = bdrv_all_find_vmstate_bs(NULL, &err); if (!bs) { error_report_err(err); return; @@ -952,7 +952,7 @@ void hmp_info_snapshots(Monitor *mon, const QDict *qdict) total = 0; for (i = 0; i < nb_sns; i++) { SnapshotEntry *next_sn; - if (bdrv_all_find_snapshot(sn_tab[i].name, NULL) == 0) { + if (bdrv_all_find_snapshot(sn_tab[i].name, NULL, NULL) == 0) { global_snapshots[total] = i; total++; QTAILQ_FOREACH(image_entry, &image_list, next) { diff --git a/block/snapshot.c b/block/snapshot.c index 6839060622..f2600a8c7f 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -385,22 +385,34 @@ int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs, return ret; } -static bool bdrv_all_snapshots_includes_bs(BlockDriverState *bs) +static bool bdrv_all_snapshots_includes_bs(BlockDriverState *bs, + strList *devices) { - if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { + if (devices) { + const char *node_name = bdrv_get_node_name(bs); + while (devices) { + if (g_str_equal(node_name, devices->value)) { + return true; + } + devices = devices->next; + } return false; - } + } else { + if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { + return false; + } - /* Include all nodes that are either in use by a BlockBackend, or that - * aren't attached to any node, but owned by the monitor. */ - return bdrv_has_blk(bs) || QLIST_EMPTY(&bs->parents); + /* Include all nodes that are either in use by a BlockBackend, or that + * aren't attached to any node, but owned by the monitor. */ + return bdrv_has_blk(bs) || QLIST_EMPTY(&bs->parents); + } } /* Group operations. All block drivers are involved. * These functions will properly handle dataplane (take aio_context_acquire * when appropriate for appropriate block drivers) */ -bool bdrv_all_can_snapshot(Error **errp) +bool bdrv_all_can_snapshot(strList *devices, Error **errp) { BlockDriverState *bs; BdrvNextIterator it; @@ -410,7 +422,7 @@ bool bdrv_all_can_snapshot(Error **errp) bool ok; aio_context_acquire(ctx); - if (bdrv_all_snapshots_includes_bs(bs)) { + if (bdrv_all_snapshots_includes_bs(bs, devices)) { ok = bdrv_can_snapshot(bs); } aio_context_release(ctx); @@ -425,7 +437,7 @@ bool bdrv_all_can_snapshot(Error **errp) return true; } -int bdrv_all_delete_snapshot(const char *name, Error **errp) +int bdrv_all_delete_snapshot(const char *name, strList *devices, Error **errp) { BlockDriverState *bs; BdrvNextIterator it; @@ -436,7 +448,7 @@ int bdrv_all_delete_snapshot(const char *name, Error **errp) int ret; aio_context_acquire(ctx); - if (bdrv_all_snapshots_includes_bs(bs) && + if (bdrv_all_snapshots_includes_bs(bs, devices) && bdrv_snapshot_find(bs, snapshot, name) >= 0) { ret = bdrv_snapshot_delete(bs, snapshot->id_str, @@ -455,7 +467,7 @@ int bdrv_all_delete_snapshot(const char *name, Error **errp) } -int bdrv_all_goto_snapshot(const char *name, Error **errp) +int bdrv_all_goto_snapshot(const char *name, strList *devices, Error **errp) { BlockDriverState *bs; BdrvNextIterator it; @@ -465,7 +477,7 @@ int bdrv_all_goto_snapshot(const char *name, Error **errp) int ret; aio_context_acquire(ctx); - if (bdrv_all_snapshots_includes_bs(bs)) { + if (bdrv_all_snapshots_includes_bs(bs, devices)) { ret = bdrv_snapshot_goto(bs, name, errp); } aio_context_release(ctx); @@ -480,7 +492,7 @@ int bdrv_all_goto_snapshot(const char *name, Error **errp) return 0; } -int bdrv_all_find_snapshot(const char *name, Error **errp) +int bdrv_all_find_snapshot(const char *name, strList *devices, Error **errp) { QEMUSnapshotInfo sn; BlockDriverState *bs; @@ -491,7 +503,7 @@ int bdrv_all_find_snapshot(const char *name, Error **errp) int ret; aio_context_acquire(ctx); - if (bdrv_all_snapshots_includes_bs(bs)) { + if (bdrv_all_snapshots_includes_bs(bs, devices)) { ret = bdrv_snapshot_find(bs, &sn, name); } aio_context_release(ctx); @@ -509,6 +521,7 @@ int bdrv_all_find_snapshot(const char *name, Error **errp) int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, BlockDriverState *vm_state_bs, uint64_t vm_state_size, + strList *devices, Error **errp) { BlockDriverState *bs; @@ -522,7 +535,7 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, if (bs == vm_state_bs) { sn->vm_state_size = vm_state_size; ret = bdrv_snapshot_create(bs, sn); - } else if (bdrv_all_snapshots_includes_bs(bs)) { + } else if (bdrv_all_snapshots_includes_bs(bs, devices)) { sn->vm_state_size = 0; ret = bdrv_snapshot_create(bs, sn); } @@ -538,7 +551,7 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, return 0; } -BlockDriverState *bdrv_all_find_vmstate_bs(Error **errp) +BlockDriverState *bdrv_all_find_vmstate_bs(strList *devices, Error **errp) { BlockDriverState *bs; BdrvNextIterator it; @@ -548,7 +561,8 @@ BlockDriverState *bdrv_all_find_vmstate_bs(Error **errp) bool found; aio_context_acquire(ctx); - found = bdrv_all_snapshots_includes_bs(bs) && bdrv_can_snapshot(bs); + found = bdrv_all_snapshots_includes_bs(bs, devices) && + bdrv_can_snapshot(bs); aio_context_release(ctx); if (found) { diff --git a/include/block/snapshot.h b/include/block/snapshot.h index ba1528eee0..1c5b0705a9 100644 --- a/include/block/snapshot.h +++ b/include/block/snapshot.h @@ -25,7 +25,7 @@ #ifndef SNAPSHOT_H #define SNAPSHOT_H - +#include "qapi/qapi-builtin-types.h" #define SNAPSHOT_OPT_BASE "snapshot." #define SNAPSHOT_OPT_ID "snapshot.id" @@ -76,15 +76,16 @@ int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs, * These functions will properly handle dataplane (take aio_context_acquire * when appropriate for appropriate block drivers */ -bool bdrv_all_can_snapshot(Error **errp); -int bdrv_all_delete_snapshot(const char *name, Error **errp); -int bdrv_all_goto_snapshot(const char *name, Error **errp); -int bdrv_all_find_snapshot(const char *name, Error **errp); +bool bdrv_all_can_snapshot(strList *devices, Error **errp); +int bdrv_all_delete_snapshot(const char *name, strList *devices, Error **errp); +int bdrv_all_goto_snapshot(const char *name, strList *devices, Error **errp); +int bdrv_all_find_snapshot(const char *name, strList *devices, Error **errp); int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, BlockDriverState *vm_state_bs, uint64_t vm_state_size, + strList *devices, Error **errp); -BlockDriverState *bdrv_all_find_vmstate_bs(Error **errp); +BlockDriverState *bdrv_all_find_vmstate_bs(strList *devices, Error **errp); #endif diff --git a/migration/savevm.c b/migration/savevm.c index 6c4d80fc5a..cdc1f2f2d8 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2653,18 +2653,18 @@ int save_snapshot(const char *name, Error **errp) return ret; } - if (!bdrv_all_can_snapshot(errp)) { + if (!bdrv_all_can_snapshot(NULL, errp)) { return ret; } /* Delete old snapshots of the same name */ if (name) { - if (bdrv_all_delete_snapshot(name, errp) < 0) { + if (bdrv_all_delete_snapshot(name, NULL, errp) < 0) { return ret; } } - bs = bdrv_all_find_vmstate_bs(errp); + bs = bdrv_all_find_vmstate_bs(NULL, errp); if (bs == NULL) { return ret; } @@ -2730,7 +2730,7 @@ int save_snapshot(const char *name, Error **errp) aio_context_release(aio_context); aio_context = NULL; - ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, errp); + ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, NULL, errp); if (ret < 0) { goto the_end; } @@ -2846,15 +2846,15 @@ int load_snapshot(const char *name, Error **errp) return -1; } - if (!bdrv_all_can_snapshot(errp)) { + if (!bdrv_all_can_snapshot(NULL, errp)) { return -1; } - ret = bdrv_all_find_snapshot(name, errp); + ret = bdrv_all_find_snapshot(name, NULL, errp); if (ret < 0) { return -1; } - bs_vm_state = bdrv_all_find_vmstate_bs(errp); + bs_vm_state = bdrv_all_find_vmstate_bs(NULL, errp); if (!bs_vm_state) { return -1; } @@ -2875,7 +2875,7 @@ int load_snapshot(const char *name, Error **errp) /* Flush all IO requests so they don't interfere with the new state. */ bdrv_drain_all_begin(); - ret = bdrv_all_goto_snapshot(name, errp); + ret = bdrv_all_goto_snapshot(name, NULL, errp); if (ret < 0) { goto err_drain; } diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c index 52f7d322e1..90e717f0c4 100644 --- a/monitor/hmp-cmds.c +++ b/monitor/hmp-cmds.c @@ -1114,7 +1114,7 @@ void hmp_delvm(Monitor *mon, const QDict *qdict) Error *err = NULL; const char *name = qdict_get_str(qdict, "name"); - bdrv_all_delete_snapshot(name, &err); + bdrv_all_delete_snapshot(name, NULL, &err); hmp_handle_error(mon, err); } -- 2.26.2