[PATCH v4 27/31] Migration: Fix error_append_hint/error_prepend usage

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

This commit (together with its neighbors) was generated by

git grep -l 'error_\(append_hint\|prepend\)(errp' | while read f; do \
spatch --sp-file scripts/coccinelle/fix-error-add-info.cocci \
--in-place $f; done

and then

./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

and then by hand, for not maintained changed files:

git commit -m "<SUB-SYSTEM>: $(< auto-msg)" <FILES>

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 migration/migration.c | 1 +
 migration/savevm.c    | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/migration/migration.c b/migration/migration.c
index 5f7e4d15e9..deaa789533 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -971,6 +971,7 @@ static bool migrate_caps_check(bool *cap_list,
                                MigrationCapabilityStatusList *params,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     MigrationCapabilityStatusList *cap;
     bool old_postcopy_cap;
     MigrationIncomingState *mis = migration_incoming_get_current();
diff --git a/migration/savevm.c b/migration/savevm.c
index bb9462a54d..f9293fe192 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2586,6 +2586,7 @@ int qemu_load_device_state(QEMUFile *f)
 
 int save_snapshot(const char *name, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     BlockDriverState *bs, *bs1;
     QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
     int ret = -1;
@@ -2790,6 +2791,7 @@ void qmp_xen_load_devices_state(const char *filename, Error **errp)
 
 int load_snapshot(const char *name, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     BlockDriverState *bs, *bs_vm_state;
     QEMUSnapshotInfo sn;
     QEMUFile *f;
-- 
2.21.0