45 lines
1.7 KiB
Diff
45 lines
1.7 KiB
Diff
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commit cdc3e7eeafa9f683214d2c15d52ef384c3de6611
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Author: aszlig <aszlig@nix.build>
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Date: Mon Mar 18 13:21:01 2019 +0100
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9pfs: Ignore O_NOATIME open flag
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Since Linux 4.19, overlayfs uses the O_NOATIME flag on its lowerdir,
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which in turn causes errors when the Nix store is mounted in the guest
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because the file owner of the store paths typically don't match the
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owner of the QEMU process.
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After submitting a patch to the overlayfs mailing list[1], it turns out
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that my patch was incomplete[2] and needs a bit more rework.
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So instead of using an incomplete kernel patch in nixpkgs, which affects
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*all* users of overlayfs, not just NixOS VM tests, I decided that for
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now it's better to patch QEMU instead.
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The change here really only ignores the O_NOATIME flag so that the
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behaviour is similar to what NFS does. From open(2):
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This flag may not be effective on all filesystems. One example is NFS,
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where the server maintains the access time.
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This change is therefore only temporary until the final fix lands in the
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stable kernel releases.
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[1]: https://www.spinics.net/lists/linux-unionfs/msg06755.html
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[2]: https://www.spinics.net/lists/linux-unionfs/msg06756.html
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Signed-off-by: aszlig <aszlig@nix.build>
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diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
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index 55821343e5..0b8425fe18 100644
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--- a/hw/9pfs/9p.c
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+++ b/hw/9pfs/9p.c
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@@ -127,7 +127,6 @@ static int dotl_to_open_flags(int flags)
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{ P9_DOTL_LARGEFILE, O_LARGEFILE },
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{ P9_DOTL_DIRECTORY, O_DIRECTORY },
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{ P9_DOTL_NOFOLLOW, O_NOFOLLOW },
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- { P9_DOTL_NOATIME, O_NOATIME },
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{ P9_DOTL_SYNC, O_SYNC },
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};
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