Bug 1972145
| Summary: | [snapshot-create-as] When snapshot creation failed, the snapshot's target block device will be removded | ||||||
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| Product: | Red Hat Enterprise Linux 9 | Reporter: | yisun | ||||
| Component: | libvirt | Assignee: | Peter Krempa <pkrempa> | ||||
| Status: | CLOSED CURRENTRELEASE | QA Contact: | yisun | ||||
| Severity: | medium | Docs Contact: | |||||
| Priority: | unspecified | ||||||
| Version: | 9.0 | CC: | jdenemar, meili, pkrempa, virt-maint, xuzhang, yicui, yisun | ||||
| Target Milestone: | beta | Keywords: | Triaged | ||||
| Target Release: | --- | ||||||
| Hardware: | x86_64 | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | libvirt-7.5.0-1.el9 | Doc Type: | If docs needed, set a value | ||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2021-12-07 21:57:54 UTC | Type: | Bug | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | 7.5.0 | ||||
| Embargoed: | |||||||
| Attachments: |
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Fixed upstream:
commit b396e9dd9ddd9745ac90ab549912de7bc5cc0b17
Author: Peter Krempa <pkrempa>
Date: Wed Jun 16 16:56:56 2021 +0200
qemuSnapshotCreateActiveExternal: Don't unlink memory snapshot image if it was existing before
When writing the memory snapshot into an existing file don't remove it
if the snapshot fails later.
Signed-off-by: Peter Krempa <pkrempa>
Reviewed-by: Ján Tomko <jtomko>
commit b30a8ee67d355f5258ece062bacaa102428e6d69
Author: Peter Krempa <pkrempa>
Date: Wed Jun 16 16:54:18 2021 +0200
conf: snapshot: rename variable holding memory snapshot file location
'file' is too generic to know what's going on. Rename it to
'memorysnapshotfile'.
Signed-off-by: Peter Krempa <pkrempa>
Reviewed-by: Ján Tomko <jtomko>
commit 308aafe289ae377d6508964512d41df2712c50b3
Author: Peter Krempa <pkrempa>
Date: Wed Jun 16 15:43:03 2021 +0200
qemuSnapshotPrepareDiskExternal: Refactor existing file check
Use the snapshot disk type from the definition now that we validate that
it matches.
Signed-off-by: Peter Krempa <pkrempa>
Reviewed-by: Ján Tomko <jtomko>
commit 919b1296032a58b27995ac2d13b035c9be86c17b
Author: Peter Krempa <pkrempa>
Date: Wed Jun 16 15:42:53 2021 +0200
qemuSnapshotPrepareDiskExternal: Enforce match between snapshot type and existing file type
The code executed later when creating a snapshot makes all decisions
based on the configured type rather than the actual type of the existing
file, while the check whether the file exists is based solely on the
on-disk type.
Since a block device is allowed to exist even when not reusing existing
files in contrast to regular files this creates a potential for a block
device to squeak past the check but then be influenced by other code
executed later. Specifically this is a problem when creating a snapshot
with the following XML:
<domainsnapshot>
<disks>
<disk name='vdb' type='file'>
<source file='/dev/sdb'/>
</disk>
</disks>
</domainsnapshot>
If the snapshot creation fails, '/dev/sdb' will be removed because it's
considered to be a regular file by the cleanup code.
Add a check that will force that the configured type matches the on-disk
state.
Additional supporting reason is that qemu stopped to accept block
devices with the 'file' backend, thus the above configuration will not
work any more. This allows us to fail sooner.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1972145
Signed-off-by: Peter Krempa <pkrempa>
Reviewed-by: Ján Tomko <jtomko>
commit 66adff17a81e9114b19b7467ce3a23e0f7ad5c3c
Author: Peter Krempa <pkrempa>
Date: Wed Jun 16 14:57:06 2021 +0200
qemuSnapshotPrepareDiskExternal: Reject creation of block devices sooner
In case when the snapshot target is of VIR_STORAGE_TYPE_BLOCK type and
doesn't exist libvirt won't be able to create it. Reject such a config
sooner.
Signed-off-by: Peter Krempa <pkrempa>
Reviewed-by: Ján Tomko <jtomko>
commit a96cc845d7518c0540234ca231b94e8171fbc5ab
Author: Peter Krempa <pkrempa>
Date: Wed Jun 16 14:57:44 2021 +0200
qemuSnapshotPrepareDiskExternal: Avoid condition squashing
Separate the 'else if' branches into nested conditions so that it's more
obvious when we'll be adding additional checks later.
Signed-off-by: Peter Krempa <pkrempa>
Reviewed-by: Ján Tomko <jtomko>
commit 006821a809e5f7876d14145b1dd7cd79bf95c7ff
Author: Peter Krempa <pkrempa>
Date: Wed Jun 16 14:49:26 2021 +0200
qemuSnapshotPrepareDiskExternal: Move temp variables into the block using them
Signed-off-by: Peter Krempa <pkrempa>
Reviewed-by: Ján Tomko <jtomko>
v7.4.0-212-gb396e9dd9d
pre-test with: libvirt-7.5.0-1.fc34.x86_64 [root@yisun-fed34 ~]# lsscsi [0:0:0:0] cd/dvd QEMU QEMU DVD-ROM 2.5+ /dev/sr0 [2:0:0:0] disk LIO-ORG device.logical- 4.0 /dev/sda [root@yisun-fed34 ~]# virsh domblklist pc Target Source --------------------------------------------- vda /var/lib/libvirt/images/vda.qcow2 vdb /var/lib/libvirt/images/vdb.qcow2 [root@yisun-fed34 ~]# virsh snapshot-create-as pc s1 --disk-only --diskspec vdb,file=/dev/sda,stype=file error: unsupported configuration: mismatch between configured type for snapshot disk 'vdb' and the type of existing file '/dev/sda' [root@yisun-fed34 ~]# ll /dev/sda brw-rw----. 1 root disk 8, 0 Jun 30 09:15 /dev/sda [root@yisun-fed34 ~]# virsh snapshot-create-as pc s1 --disk-only --diskspec vdb,file=/dev/sda,stype=block Domain snapshot s1 created Verified on libvirt-7.5.0-1.el9.x86_64 1. have a running vm [root@ibm-x3250m6-10 images]# virsh domstate vm1 running [root@ibm-x3250m6-10 images]# virsh domblklist vm1 Target Source ---------------------------------------------------------------- vda /var/lib/libvirt/images/RHEL-9.0-x86_64-latest.qcow2 vdb /var/lib/libvirt/images/vdb.qcow2 2. have local block devices sda and sdb [root@ibm-x3250m6-10 images]# lsscsi [0:0:0:0] disk ATA ST1000NX0423 LE43 /dev/sda [6:0:0:0] disk LIO-ORG device.logical- 4.0 /dev/sdb 3. create disk only snapshot for vm1, but use wrong config '--diskspec vdb,file=/dev/sdb,stype=file' [root@ibm-x3250m6-10 images]# virsh snapshot-create-as vm1 s1 --disk-only --diskspec vdb,file=/dev/sdb,stype=file error: unsupported configuration: mismatch between configured type for snapshot disk 'vdb' and the type of existing file '/dev/sdb' 4. /dev/sdb still existing as block device [root@ibm-x3250m6-10 images]# ll /dev/sdb brw-rw----. 1 root disk 8, 16 Jul 20 09:05 /dev/sdb 5. create disk + mem snapshot, but use wrong config '--diskspec vdb,file=/dev/sda,stype=file --memspec file=/dev/sdb' [root@ibm-x3250m6-10 images]# virsh snapshot-create-as vm1 s1 --diskspec vdb,file=/dev/sda,stype=file --memspec file=/dev/sdb error: unsupported configuration: mismatch between configured type for snapshot disk 'vdb' and the type of existing file '/dev/sda' 6. /dev/sdb still existing as block device [root@ibm-x3250m6-10 images]# ll /dev/sdb brw-rw----. 1 root disk 8, 16 Jul 20 09:07 /dev/sdb |
Created attachment 1791217 [details] libvirtd-debug.log Description: [snapshot-create-as] When snapshot creation failed, the snapshot's target block device will be removded Versions: libvirt-7.4.0-1.el9.x86_64 qemu-kvm-6.0.0-5.el9.x86_64 How reproducible: 100% Steps: 1. prepare a running vm with a disk, here we use vdb [root@dell-per730-61 ~]# virsh dumpxml avocado-vt-vm1 ... <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/var/lib/libvirt/images/vdb.qcow2' index='1'/> <backingStore/> <target dev='vdb' bus='virtio'/> <alias name='virtio-disk1'/> <address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/> </disk> ... 2. make sure you have a extra block device can be used on host, here we can use a usb disk or prepare a iscsi lun [root@dell-per730-61 ~]# lsscsi [0:0:0:0] disk SanDisk Ultra USB 3.0 1.00 /dev/sdb [root@dell-per730-61 ~]# ll /dev/sdb brw-rw----. 1 root disk 8, 16 Jun 15 06:10 /dev/sdb 3. create sanpshot with stype=file to trigger an error [root@dell-per730-61 ~]# virsh snapshot-create-as avocado-vt-vm1 s1 --disk-only --diskspec vdb,file=/dev/sdb,stype=file error: internal error: unable to execute QEMU command 'blockdev-add': 'file' driver requires '/dev/sdb' to be a regular file 4. check the /dev/sdb, it's gone [root@dell-per730-61 ~]# ll /dev/sdb ls: cannot access '/dev/sdb': No such file or directory [root@dell-per730-61 ~]# lsscsi [0:0:0:0] disk SanDisk Ultra USB 3.0 1.00 - Additional steps to test mem snapshot target, it's also removed when snapshot failed 5. prepare a block device sdc [root@dell-per730-61 ~]# lsscsi ... [0:0:0:0] disk SanDisk Ultra USB 3.0 1.00 /dev/sdb [12:0:0:0] disk LIO-ORG device.logical- 4.0 /dev/sdc ... 6. ln /tmp/vdb.s1 to a block device to trigger the error [root@dell-per730-61 ~]# ln -s /dev/sdb /tmp/vdb.s1 [root@dell-per730-61 ~]# virsh snapshot-create-as avocado-vt-vm1 s1 --diskspec vdb,file=/tmp/vdb.s1,stype=file --memspec file=/dev/sdc error: internal error: unable to execute QEMU command 'blockdev-add': 'file' driver requires '/tmp/vdb.s1' to be a regular file 7. sdc gone after cmd failed, sdc is the mem snapshot target device [root@dell-per730-61 ~]# ll /dev/sdc ls: cannot access '/dev/sdc': No such file or directory [root@dell-per730-61 ~]# lsscsi [0:0:0:0] disk SanDisk Ultra USB 3.0 1.00 /dev/sdb [12:0:0:0] disk LIO-ORG device.logical- 4.0 - Expected result: When snapshot failed, libvirt should not remove the target block device Actual result: block device removed from host when snapshot failed.