[PATCH] virsh: Fix logic wrt to --current flag in cmdSetmem
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API. Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1961118 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- tools/virsh-domain.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c index 0825f82522..bd9325a1d8 100644 --- a/tools/virsh-domain.c +++ b/tools/virsh-domain.c @@ -9025,7 +9025,7 @@ cmdSetmem(vshControl *ctl, const vshCmd *cmd) } kibibytes = VIR_DIV_UP(bytes, 1024); - if (flags == 0) { + if (flags == VIR_DOMAIN_AFFECT_LIVE) { if (virDomainSetMemory(dom, kibibytes) != 0) ret = false; } else { -- 2.26.3
On Tue, May 18, 2021 at 02:30:06PM +0200, Michal Privoznik wrote:
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API.
Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1961118 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- tools/virsh-domain.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
I would add a comment in the code as well to help other developers understand the logic without looking up the commit message. Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
On a Tuesday in 2021, Michal Privoznik wrote:
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API.
Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a
before that commit, if the user did not specify any of: config, live, current we used the old API. After this change, the new API will be used for those cases. Jano
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1961118 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- tools/virsh-domain.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
On 5/18/21 3:02 PM, Ján Tomko wrote:
On a Tuesday in 2021, Michal Privoznik wrote:
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API.
Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a
before that commit, if the user did not specify any of: config, live, current we used the old API.
After this change, the new API will be used for those cases.
Will it? I think that with just --live @flags will be VIR_DOMAIN_AFFECT_CURRENT | VIR_DOMAIN_AFFECT_LIVE, which is effectively just VIR_DOMAIN_AFFECT_LIVE which means that the old API is used. Am I missing something? Michal
On Tue, May 18, 2021 at 03:02:55PM +0200, Ján Tomko wrote:
On a Tuesday in 2021, Michal Privoznik wrote:
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API.
Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a
before that commit, if the user did not specify any of: config, live, current we used the old API.
After this change, the new API will be used for those cases.
The question is if we support using upstream virsh with old libvirt where only non-flags API is available. If not we should drop the non-flags API usage from virsh completely. Pavel
On 5/18/21 3:12 PM, Pavel Hrdina wrote:
On Tue, May 18, 2021 at 03:02:55PM +0200, Ján Tomko wrote:
On a Tuesday in 2021, Michal Privoznik wrote:
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API.
Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a
before that commit, if the user did not specify any of: config, live, current we used the old API.
After this change, the new API will be used for those cases.
The question is if we support using upstream virsh with old libvirt where only non-flags API is available. If not we should drop the non-flags API usage from virsh completely.
I think in general we do. In this specific case, virDomainSetMemoryFlags() API was introduced in v0.9.0 release (which is 10 years ago). And since we dropped RHEL-7 support recently and the oldest QEMU we support is from late 2017 our attempt to be that backwards compatible is questionable IMO. But anyway - with this proposed patch the older API is called in more cases than it was before I touched the code => compatibility++. Michal
On Tue, May 18, 2021 at 03:17:56PM +0200, Michal Prívozník wrote:
On 5/18/21 3:12 PM, Pavel Hrdina wrote:
On Tue, May 18, 2021 at 03:02:55PM +0200, Ján Tomko wrote:
On a Tuesday in 2021, Michal Privoznik wrote:
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API.
Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a
before that commit, if the user did not specify any of: config, live, current we used the old API.
After this change, the new API will be used for those cases.
The question is if we support using upstream virsh with old libvirt where only non-flags API is available. If not we should drop the non-flags API usage from virsh completely.
I think in general we do. In this specific case, virDomainSetMemoryFlags() API was introduced in v0.9.0 release (which is 10 years ago). And since we dropped RHEL-7 support recently and the oldest QEMU we support is from late 2017 our attempt to be that backwards compatible is questionable IMO.
Exactly my question. We have some support matrix where libvirt should be able to compile and run but there is no explicit support policy for using virsh with old libvirt or for obsolete APIs that should not be used. I would vote to use the same matrix as we already have. That would allow us to remove probably all non-flags APIs from virsh code. Pavel
But anyway - with this proposed patch the older API is called in more cases than it was before I touched the code => compatibility++.
Michal
On Tue, May 18, 2021 at 15:55:45 +0200, Pavel Hrdina wrote:
On Tue, May 18, 2021 at 03:17:56PM +0200, Michal Prívozník wrote:
On 5/18/21 3:12 PM, Pavel Hrdina wrote:
On Tue, May 18, 2021 at 03:02:55PM +0200, Ján Tomko wrote:
On a Tuesday in 2021, Michal Privoznik wrote:
In my commit of v7.1.0-rc1~376 I've simplified the logic of handling @flags. My assumption back then was that calling virDomainSetMemory() is equivalent to virDomainSetMemoryFlags(flags = 0). But that is not the case, because it is equivalent to virDomainSetMemoryFlags(flags = VIR_DOMAIN_AFFECT_LIVE). Fix the condition that calls the old API.
Fixes: b5e267e8c59a257652f88d034cb1e0ce1ed4b58a
before that commit, if the user did not specify any of: config, live, current we used the old API.
After this change, the new API will be used for those cases.
The question is if we support using upstream virsh with old libvirt where only non-flags API is available. If not we should drop the non-flags API usage from virsh completely.
I think in general we do. In this specific case, virDomainSetMemoryFlags() API was introduced in v0.9.0 release (which is 10 years ago). And since we dropped RHEL-7 support recently and the oldest QEMU we support is from late 2017 our attempt to be that backwards compatible is questionable IMO.
Exactly my question. We have some support matrix where libvirt should be able to compile and run but there is no explicit support policy for using virsh with old libvirt or for obsolete APIs that should not be used. I would vote to use the same matrix as we already have.
That would allow us to remove probably all non-flags APIs from virsh code.
This fix, well a variation of it removing the old API would be the only acceptable variant here. The original code in virsh prior to the change would call the old API also when no flag was used. This patch is not really fixing the old behaviour though, because with no flag you get the behavior of '--current' rather than the pre-existing behavior of implying '--live'. Thus we either declare that we do want to change the behaviour in virsh and use it as an excuse to delete the use of the old api, or this patch needs to be fixed more to restore the logic, or just revert the original commit. But this patch as-is is wrong and is not really fixing the behaviour without adding more regression.
participants (5)
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Ján Tomko -
Michal Privoznik -
Michal Prívozník
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Pavel Hrdina -
Peter Krempa