Re: [PATCH 2/3] qemuSnapshotCreateActiveExternal: Don't thaw filesystems when freeze fails
On Mon, Feb 15, 2021 at 06:27:50PM +0100, Peter Krempa wrote:
If we didn't freeze any filesystems we should not even attempt
thawing
them. Additionally 'guest-fsfreeze-freeze' fails if the filesystems are
already frozen, where thawing them may break users data integrity if
they used VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE accidentally after an
explicit virDomainFSFreeze and the next snapshot without that flag would
be taken with already thawed filesystems.
This effectively reverts 7c736bab06479ccec59df69fb79a5c06d112d8fb .
Libvirt nowadays checks whether the guest agent is connected and pings
it before issuing an command so it's very unlikely that we'd end up in a
situation where qemuSnapshotCreateActiveExternal froze filesystems and
didn't thaw them.
It would happen if QEMU returned different reply for the command then
we expect which could be considered as QEMU bug.
In that case I guess it's better to leave the VM with frozen filesystems
and exit the API with error like this patch will do.
Additionally we now discourage the use of
VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE since users have better control if
they freeze the FS themselves.
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
---
src/qemu/qemu_snapshot.c | 28 ++++++++++++----------------
1 file changed, 12 insertions(+), 16 deletions(-)
Reviewed-by: Pavel Hrdina <phrdina(a)redhat.com>
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