rbd: allow importing/exporting block devices

[petrutlucian94]

rbd: allow importing/exporting block devices

This change checks if we're exporting to or importing from a block device. If so, we have to:

• ensure that writes are sector aligned
• ensure that writes are not skipped in case of zero buffers
• avoid fstat, use blkdev.get_size to retrieve the disk size (DeviceIoControl on Windows)
• avoid ftruncate
• avoid opening with O_CREAT | O_EXCL

This enables to do the following:

set-disk -Number 1 -IsReadOnly $false -IsOffline $true
rbd export test_64m@snap2 \\.\PhysicalDrive1
rbd import \\.\PhysicalDrive1 test_64m_import

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[petrutlucian94]

Wasn't sure whether to mark this as a bug or as a feature. We used to have this debate in Openstack and Nova cores usually said that if a patch enables a feature that never worked before, it's considered a feature and not a bug fix.

[github-actions]

This pull request can no longer be automatically merged: a rebase is needed and changes have to be manually resolved

[petrutlucian94]

jenkins test windows

[idryomov]

This enables to do the following:
[...]
rbd export-diff test_64m@snap2 --from-snap snap1 snap2_snap1

I don't see anything special about this command -- it seems to be exporting to a regular file?

[petrutlucian94]

This enables to do the following:
[...]
rbd export-diff test_64m@snap2 --from-snap snap1 snap2_snap1

I don't see anything special about this command -- it seems to be exporting to a regular file?

Indeed, initially I was thinking about showcasing a block device but it probably doesn't really make sense to export a diff to a raw block device.

I'll address the remaining comments ASAP.

[petrutlucian94]

jenkins test make check

[petrutlucian94]

jenkins test windows

[petrutlucian94]

jenkins test api

[rzarzynski]

From core PR scrub: the change in common isn't interesting from the core's PoV.

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity for 60 days. It will be closed if no further activity occurs for another 30 days.
If you are a maintainer or core committer, please follow-up on this pull request to identify what steps should be taken by the author to move this proposed change forward.
If you are the author of this pull request, thank you for your proposed contribution. If you believe this change is still appropriate, please ensure that any feedback has been addressed and ask for a code review.

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity for 60 days. It will be closed if no further activity occurs for another 30 days.
If you are a maintainer or core committer, please follow-up on this pull request to identify what steps should be taken by the author to move this proposed change forward.
If you are the author of this pull request, thank you for your proposed contribution. If you believe this change is still appropriate, please ensure that any feedback has been addressed and ask for a code review.

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity for 60 days. It will be closed if no further activity occurs for another 30 days.
If you are a maintainer or core committer, please follow-up on this pull request to identify what steps should be taken by the author to move this proposed change forward.
If you are the author of this pull request, thank you for your proposed contribution. If you believe this change is still appropriate, please ensure that any feedback has been addressed and ask for a code review.

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity for 60 days. It will be closed if no further activity occurs for another 30 days.
If you are a maintainer or core committer, please follow-up on this pull request to identify what steps should be taken by the author to move this proposed change forward.
If you are the author of this pull request, thank you for your proposed contribution. If you believe this change is still appropriate, please ensure that any feedback has been addressed and ask for a code review.

[petrutlucian94]

jenkins test make check

[petrutlucian94]

jenkins test make check

[petrutlucian94]

@idryomov this PR already went through a round of reviews, do you think we can get it in?

[idryomov]

@idryomov this PR already went through a round of reviews, do you think we can get it in?

The workunit isn't wired up (i.e. wouldn't actually run), so that would need to be fixed at the very least. I'll try to do another pass sometime this week or early next week.

[idryomov]

I'll have more comments on the workunit, but wanted to get clarity on the use cases for exporting and some semantics first.

[petrutlucian94]

jenkins test make check

[petrutlucian94]

@idryomov Thanks for reviewing this patch, please let me know if there's anything else that needs to be updated.

[petrutlucian94]

I've prepared some Windows tests as well:

petrutlucian94@62d9178

That commit is based on another PR, which breaks the Windows Python tests into separate modules and makes the code reusable: #52560. I think I'll wait for this PR to merge and then I'll submit the Windows export tests there.

[petrutlucian94]

jenkins test make check arm64

[petrutlucian94]

jenkins test make check arm64

[petrutlucian94]

@idryomov I've addressed the comments and squashed the commits, I think it's ready to merge. Thanks again for the review.

[petrutlucian94]

jenkins test make check arm64