Use rename of directories instead of symbolic links in boot partition. #1967
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[APPROVALNOTIFIER] This PR is NOT APPROVED This pull-request has been approved by: valentindavid The full list of commands accepted by this bot can be found here.
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Hi @valentindavid. Thanks for your PR. I'm waiting for a ostreedev member to verify that this patch is reasonable to test. If it is, they should reply with Once the patch is verified, the new status will be reflected by the I understand the commands that are listed here. Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. |
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Can one of the admins verify this patch?
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valentindavid
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The challenge with this is that the ESP is vfat, and therefore rename will always be non-atomic. It's still better than what I'm doing now (manually copying files into /efi) #1951 |
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Systemd boot requires the boot partition to be the EFI partition which means FAT is required. OSTree uses symlinking as a way to do atomic update. There is no solution yet for atomic update of FAT partitions. THis patch however changes symlinking by doing directory move which can be atomic in conditions. In practice filesystems with symbolic link support usually also support atomic rename of directories. But this allows to also work when no atomic update is working. Patch was submitted upstream as ostreedev/ostree#1967
Systemd boot requires the boot partition to be the EFI partition which means FAT is required. OSTree uses symlinking as a way to do atomic update. There is no solution yet for atomic update of FAT partitions. THis patch however changes symlinking by doing directory move which can be atomic in conditions. In practice filesystems with symbolic link support usually also support atomic rename of directories. But this allows to also work when no atomic update is working. Patch was submitted upstream as ostreedev/ostree#1967
Systemd boot requires the boot partition to be the EFI partition which means FAT is required. OSTree uses symlinking as a way to do atomic update. There is no solution yet for atomic update of FAT partitions. THis patch however changes symlinking by doing directory move which can be atomic in conditions. In practice filesystems with symbolic link support usually also support atomic rename of directories. But this allows to also work when no atomic update is working. Patch was submitted upstream as ostreedev/ostree#1967
Systemd boot requires the boot partition to be the EFI partition which means FAT is required. OSTree uses symlinking as a way to do atomic update. There is no solution yet for atomic update of FAT partitions. THis patch however changes symlinking by doing directory move which can be atomic in conditions. In practice filesystems with symbolic link support usually also support atomic rename of directories. But this allows to also work when no atomic update is working. Patch was submitted upstream as ostreedev/ostree#1967
Systemd boot requires the boot partition to be the EFI partition which means FAT is required. OSTree uses symlinking as a way to do atomic update. There is no solution yet for atomic update of FAT partitions. THis patch however changes symlinking by doing directory move which can be atomic in conditions. In practice filesystems with symbolic link support usually also support atomic rename of directories. But this allows to also work when no atomic update is working. Patch was submitted upstream as ostreedev/ostree#1967
Systemd boot requires the boot partition to be the EFI partition which means FAT is required. OSTree uses symlinking as a way to do atomic update. There is no solution yet for atomic update of FAT partitions. THis patch however changes symlinking by doing directory move which can be atomic in conditions. In practice filesystems with symbolic link support usually also support atomic rename of directories. But this allows to also work when no atomic update is working. Patch was submitted upstream as ostreedev/ostree#1967
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Is this PR still proposed or abandoned? |
I can rebase and take care of it a bit. But since there was no interaction from maintainers, then I am not sure whether they are considering it. |
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@valentindavid have you been able to pay some attention to this issue again? The changes are highly anticipated here, in one form or another. Thanks. |
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@mwleeds @rfairley any chance to take a look to this? We currently need this to make GNOME images work, see https://gitlab.gnome.org/GNOME/gnome-build-meta/-/commit/79fb62e0d243a21ab58dc1dda439c23db5d474ab |
This uses `renameat2` to do atomic swap of the loader directory in the boot partition. It fallsback to non-atomic rename. This stays atomic on filesystems supporting links but also provide a non-atomic behavior when filesystem does not provide any atomic alternative. This is working with SystemD boot on EFI using boot loader specifications. There is still the issue of losing `/loader/loader.conf` with SystemD boot.
valentindavid
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@cgwalters Hey! Any chance to take a look to this? |
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Friendly ping. |
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@valentindavid This PR conflicts with upstream again. GNOME OS uses an ancient version of OSTree so they have yet to run into this issue, but on my OS I just updated to the latest version and I'm about to be downgrading again because this patch is broken. @cgwalters Is there any chance for this patch to be reviewed or considered at all? Without this patch, I have to follow every single |
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updated.txt |
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Any news on this? |
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@valentindavid: PR needs rebase. Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. |
This implements @AdrianVovk idea from #1719 (comment) to solve issue #1719.
This uses
renameat2to do atomic swap of the loader directory in theboot partition. It fallsback to non-atomic rename. This stays atomic
on filesystems supporting links but also provide a non-atomic behavior
when filesystem does not provide any atomic alternative.
This is working with SystemD boot on EFI using boot loader
specifications.
There is still the issue of losing
/loader/loader.confwith SystemDboot. Maybe we should think about copying other files from previous loader directories.