From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58530) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d47ft-0004G1-DZ for qemu-devel@nongnu.org; Fri, 28 Apr 2017 11:19:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d47fp-0000wr-DG for qemu-devel@nongnu.org; Fri, 28 Apr 2017 11:19:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36440) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d47fp-0000wW-3t for qemu-devel@nongnu.org; Fri, 28 Apr 2017 11:19:09 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C95AA3DBE6 for ; Fri, 28 Apr 2017 15:19:07 +0000 (UTC) From: Markus Armbruster References: <20170425102446.4008-1-quintela@redhat.com> <20170425102446.4008-7-quintela@redhat.com> <20170428144729.GB3276@work-vm> Date: Fri, 28 Apr 2017 17:19:03 +0200 In-Reply-To: <20170428144729.GB3276@work-vm> (David Alan Gilbert's message of "Fri, 28 Apr 2017 15:47:30 +0100") Message-ID: <87y3uk8src.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH 6/6] migration: Pass Error ** argument to {save, load}_vmstate List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: Juan Quintela , lvivier@redhat.com, qemu-devel@nongnu.org, peterx@redhat.com "Dr. David Alan Gilbert" writes: > * Juan Quintela (quintela@redhat.com) wrote: >> This way we use the "normal" way of printing errors for hmp commands. >> >> -- >> Paolo suggestion >> >> Signed-off-by: Juan Quintela > > > >> +int save_vmstate(const char *name, Error **errp) >> { >> BlockDriverState *bs, *bs1; >> QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1; >> @@ -2076,29 +2076,27 @@ int save_vmstate(const char *name) >> uint64_t vm_state_size; >> qemu_timeval tv; >> struct tm tm; >> - Error *local_err = NULL; >> AioContext *aio_context; >> >> if (!bdrv_all_can_snapshot(&bs)) { >> - error_report("Device '%s' is writable but does not support snapshots", >> - bdrv_get_device_name(bs)); >> + error_setg(errp, "Device '%s' is writable but does not support " >> + "snapshots", bdrv_get_device_name(bs)); >> return ret; >> } >> >> /* Delete old snapshots of the same name */ >> if (name) { >> - ret = bdrv_all_delete_snapshot(name, &bs1, &local_err); >> + ret = bdrv_all_delete_snapshot(name, &bs1, errp); >> if (ret < 0) { >> - error_reportf_err(local_err, >> - "Error while deleting snapshot on device '%s': ", >> - bdrv_get_device_name(bs1)); >> + error_prepend(errp, "Error while deleting snapshot on device " >> + "'%s': ", bdrv_get_device_name(bs1)); > > I thought the rule was that you had to use a local_err and use error_propagate? > (I hate that rule) Quote qapi/error.h: * Receive an error and pass it on to the caller: * Error *err = NULL; * foo(arg, &err); * if (err) { * handle the error... * error_propagate(errp, err); * } * where Error **errp is a parameter, by convention the last one. * * Do *not* "optimize" this to * foo(arg, errp); * if (*errp) { // WRONG! * handle the error... * } * because errp may be NULL! * * But when all you do with the error is pass it on, please use * foo(arg, errp); * for readability. Neglects to mention you can error_prepend() and still avoid error_propagate(), but the comment is long enough as it is. >> return ret; >> } >> } >> >> bs = bdrv_all_find_vmstate_bs(); >> if (bs == NULL) { >> - error_report("No block device can accept snapshots"); >> + error_setg(errp, "No block device can accept snapshots"); >> return ret; >> } >> aio_context = bdrv_get_aio_context(bs); >> @@ -2107,7 +2105,7 @@ int save_vmstate(const char *name) >> >> ret = global_state_store(); >> if (ret) { >> - error_report("Error saving global state"); >> + error_setg(errp, "Error saving global state"); >> return ret; >> } >> vm_stop(RUN_STATE_SAVE_VM); >> @@ -2139,21 +2137,20 @@ int save_vmstate(const char *name) >> /* save the VM state */ >> f = qemu_fopen_bdrv(bs, 1); >> if (!f) { >> - error_report("Could not open VM state file"); >> + error_setg(errp, "Could not open VM state file"); >> goto the_end; >> } >> - ret = qemu_savevm_state(f, &local_err); >> + ret = qemu_savevm_state(f, errp); >> vm_state_size = qemu_ftell(f); >> qemu_fclose(f); >> if (ret < 0) { >> - error_report_err(local_err); >> goto the_end; >> } >> >> ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, &bs); >> if (ret < 0) { >> - error_report("Error while creating snapshot on '%s'", >> - bdrv_get_device_name(bs)); >> + error_setg(errp, "Error while creating snapshot on '%s'", >> + bdrv_get_device_name(bs)); >> goto the_end; >> } >> >> @@ -2226,7 +2223,7 @@ void qmp_xen_load_devices_state(const char *filename, Error **errp) >> migration_incoming_state_destroy(); >> } >> >> -int load_vmstate(const char *name) >> +int load_vmstate(const char *name, Error **errp) >> { >> BlockDriverState *bs, *bs_vm_state; >> QEMUSnapshotInfo sn; >> @@ -2236,20 +2233,22 @@ int load_vmstate(const char *name) >> MigrationIncomingState *mis = migration_incoming_get_current(); >> >> if (!bdrv_all_can_snapshot(&bs)) { >> - error_report("Device '%s' is writable but does not support snapshots", >> - bdrv_get_device_name(bs)); >> + error_setg(errp, >> + "Device '%s' is writable but does not support snapshots", >> + bdrv_get_device_name(bs)); >> return -ENOTSUP; >> } >> ret = bdrv_all_find_snapshot(name, &bs); >> if (ret < 0) { >> - error_report("Device '%s' does not have the requested snapshot '%s'", >> - bdrv_get_device_name(bs), name); >> + error_setg(errp, >> + "Device '%s' does not have the requested snapshot '%s'", >> + bdrv_get_device_name(bs), name); >> return ret; >> } >> >> bs_vm_state = bdrv_all_find_vmstate_bs(); >> if (!bs_vm_state) { >> - error_report("No block device supports snapshots"); >> + error_setg(errp, "No block device supports snapshots"); >> return -ENOTSUP; >> } >> aio_context = bdrv_get_aio_context(bs_vm_state); >> @@ -2261,8 +2260,8 @@ int load_vmstate(const char *name) >> if (ret < 0) { >> return ret; >> } else if (sn.vm_state_size == 0) { >> - error_report("This is a disk-only snapshot. Revert to it offline " >> - "using qemu-img."); >> + error_setg(errp, "This is a disk-only snapshot. Revert to it " >> + " offline using qemu-img"); >> return -EINVAL; >> } >> >> @@ -2271,7 +2270,7 @@ int load_vmstate(const char *name) >> >> ret = bdrv_all_goto_snapshot(name, &bs); >> if (ret < 0) { >> - error_report("Error %d while activating snapshot '%s' on '%s'", >> + error_setg(errp, "Error %d while activating snapshot '%s' on '%s'", >> ret, name, bdrv_get_device_name(bs)); >> return ret; >> } >> @@ -2279,7 +2278,7 @@ int load_vmstate(const char *name) >> /* restore the VM state */ >> f = qemu_fopen_bdrv(bs_vm_state, 0); >> if (!f) { >> - error_report("Could not open VM state file"); >> + error_setg(errp, "Could not open VM state file"); >> return -EINVAL; >> } >> >> @@ -2293,7 +2292,7 @@ int load_vmstate(const char *name) >> >> migration_incoming_state_destroy(); >> if (ret < 0) { >> - error_report("Error %d while loading VM state", ret); >> + error_setg(errp, "Error %d while loading VM state", ret); >> return ret; >> } >> >> diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c >> index 8cced46..fdc4353 100644 >> --- a/replay/replay-snapshot.c >> +++ b/replay/replay-snapshot.c >> @@ -62,14 +62,16 @@ void replay_vmstate_register(void) >> >> void replay_vmstate_init(void) >> { >> + Error *err = NULL; >> + >> if (replay_snapshot) { >> if (replay_mode == REPLAY_MODE_RECORD) { >> - if (save_vmstate(replay_snapshot) != 0) { >> + if (save_vmstate(replay_snapshot, &err) != 0) { >> error_report("Could not create snapshot for icount record"); >> exit(1); >> } >> } else if (replay_mode == REPLAY_MODE_PLAY) { >> - if (load_vmstate(replay_snapshot) != 0) { >> + if (load_vmstate(replay_snapshot, &err) != 0) { >> error_report("Could not load snapshot for icount replay"); >> exit(1); >> } > > How do either of the contents of the 'err' get reported - they're not > printed at all are they? > (I don't like error_abort, I'd rather see the other message as well). I guess you mean &error_fatal. Consider error_report_err(). > > Dave > >> diff --git a/vl.c b/vl.c >> index 0b4ed52..8b3ec2e 100644 >> --- a/vl.c >> +++ b/vl.c >> @@ -4681,7 +4681,9 @@ int main(int argc, char **argv, char **envp) >> if (replay_mode != REPLAY_MODE_NONE) { >> replay_vmstate_init(); >> } else if (loadvm) { >> - if (load_vmstate(loadvm) < 0) { >> + Error *local_err = NULL; >> + if (load_vmstate(loadvm, &local_err) < 0) { >> + error_report_err(local_err); >> autostart = 0; >> } >> } >> -- >> 2.9.3 >> >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK