mount-v2: workaround for multiple external bindmounts with no common root #1898
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Nice! I will try it out tomorrow. |
Codecov Report
@@ Coverage Diff @@
## criu-dev #1898 +/- ##
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+ Coverage 69.20% 69.68% +0.47%
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Files 126 128 +2
Lines 33355 32201 -1154
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- Hits 23083 22438 -645
+ Misses 10272 9763 -509
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@Snorch Would it be possible to add a test for this case? |
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I just tested it and it does not seem to help: To replicate this you can try the following commands: |
Snorch
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Sorry it was a stupid mistake: After this I have test passing: |
Sure, will do tomorrow. (done) |
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The current version of the PR works with runc. Thanks. I also restarted the failing tests. |
avagin
reviewed
May 31, 2022
This helper restores master_id and shared_id of first mount in the sharing group. It first copies sharing from either external source or internal parent sharing group and makes master_id from shared_id. Next it creates new shared_id when needed. All other mounts except first are just copied from the first one. Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
…root It's a problem when while restoring sharing group we need to copy sharing between two mounts with non-intersecting roots, because kernel does not allow it. We have a case opencontainers/runc#3442, where runc adds different devtmpfs file-bindmounts to container and there is no fsroot mount in container for this devtmpfs, thus mount-v2 faces the above problem. Luckily for the case of external mounts which are in one sharing group and which have non-intersecting roots, these mounts likely only have external master with no sharing, so we can just copy sharing from external source and make it slave as a workaround. checkpoint-restore#1886 Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Snorch
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I've added a more detailed comment in code and also a bit simplified the code by splitting restore_one_sharing function of restoring sharing on first mount of shared group, and reusing it in w/a. This makes clear that w/a is about restoring "other" mount similar to how we've restored "first" mount in case we can't copy from "first". upd: And rechecked runc usecase, looks working after this change. |
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It's a problem when while restoring sharing group we need to copy
sharing between to mounts with non-intersecting roots, because kernel
does not allow it.
We have a case opencontainers/runc#3442, where
runc adds different devtmpfs file-bindmounts to container and there is
no fsroot mount in container for this devtmpfs, thus mount-v2 faces the
above problem.
Luckily for the case of external mounts which are in one sharing group
and which have non-intersecting roots, these mounts likely only have
external master with no sharing, so we can just copy sharing from
external source and make it slave as a workaround.
#1886
Signed-off-by: Pavel Tikhomirov ptikhomirov@virtuozzo.com