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Problem: On remap/attach of device (i.e. nodeplugin restart), there is no way for rbd-nbd to defend if the backend storage is matching with the initial backend storage. Say, if an initial map request for backend "pool1/image1" got mapped to /dev/nbd0 and the userspace process is terminated (on nodeplugin restart). A next remap/attach (nodeplugin start) request within reattach-timeout is allowed to use /dev/nbd0 for a different backend "pool1/image2" For example, an operation like below could be dangerous: $ sudo rbd-nbd map --try-netlink rbd-pool/ext4-image /dev/nbd0 $ sudo blkid /dev/nbd0 /dev/nbd0: UUID="bfc444b4-64b1-418f-8b36-6e0d170cfc04" TYPE="ext4" $ sudo pkill -15 rbd-nbd <-- nodeplugin terminate $ sudo rbd-nbd attach --try-netlink --device /dev/nbd0 rbd-pool/xfs-image /dev/nbd0 $ sudo blkid /dev/nbd0 /dev/nbd0: UUID="d29bf343-6570-4069-a9ea-2fa156ced908" TYPE="xfs" Solution: rbd-nbd/kernel now provides a way to keep some metadata in sysfs to identify between the device and the backend, so that when a remap/attach request is made, rbd-nbd can compare and avoid such dangerous operations. With the provided solution, as part of the initial map request, backend cookie (ceph-csi VOLID) can be stored in the sysfs per device config, so that on a remap/attach request rbd-nbd will check and validate if the backend per device cookie matches with the initial map backend with the help of cookie. At Ceph-csi we use VOLID as device cookie, which will be unique, we pass the VOLID as cookie at map and use the same at the time of attach, that way rbd-nbd can identify backends and their matching devices. Requires: https://github.com/ceph/ceph/pull/41323 https://lkml.org/lkml/2021/4/29/274 Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com> |
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| cephfs | ||
| controller | ||
| csi-common | ||
| journal | ||
| kms | ||
| liveness | ||
| rbd | ||
| util | ||