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kzys opened this issue Oct 7, 2019 · 1 comment
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Mounting block devices as virtio devices doesn't work correctly #1316

kzys opened this issue Oct 7, 2019 · 1 comment
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Priority: High Indicates than an issue or pull request should be resolved ahead of issues or pull requests labelled Type: Bug Indicates an unexpected problem or unintended behavior

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kzys commented Oct 7, 2019 •
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While investigating firecracker-microvm/firecracker-containerd#253, we have found a small gap regarding virtio block device support on Firecracker.

Currently Firecracker is using std::fs::metadata() to check the size of a virtio block device, which ultimately calls stat() on Unix.

However firecracker-containerd is using a loopback device as the backing file for a virtio block device. On a lookback device, the size from stat() is always zero.

Can Firecracker support our usecase by inspecting the size of the file more deeply? You probably can use BLKGETSIZE64 ioctl.

Thanks,
@kzys kzys changed the title Support loopback devices as Mouting block devices as virtio devices doesn't work correctly Oct 7, 2019
@alxiord alxiord added Feature: Emulation Priority: Low Indicates that an issue or pull request should be resolved behind issues or pull requests labelled ` Priority: High Indicates than an issue or pull request should be resolved ahead of issues or pull requests labelled Type: Bug Indicates an unexpected problem or unintended behavior and removed Priority: Low Indicates that an issue or pull request should be resolved behind issues or pull requests labelled ` labels Oct 8, 2019
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alxiord commented Oct 8, 2019

Hi @kzys, thank you for the report and investigation! This looks like a bug, and will be addressed as soon as possible. However, if in the meantime you have a fix ready, PRs are welcome!

@iulianbarbu iulianbarbu self-assigned this Oct 9, 2019
@sandreim sandreim changed the title Mouting block devices as virtio devices doesn't work correctly Mounting block devices as virtio devices doesn't work correctly Oct 9, 2019
kzys added a commit to kzys/firecracker that referenced this issue Nov 5, 2019
@kzys
Fix the size of a virtio device, backed by a block device
a76548f 
When a virtio device is backed by a block device, the actual size of
the block device file doesn't represent the size as a virtio device.

Fixes firecracker-microvm#1316
@kzys kzys mentioned this issue Nov 5, 2019
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kzys added a commit to kzys/firecracker that referenced this issue Nov 5, 2019
@kzys
Fix the size of a virtio device, backed by a block device
551f581 
When a virtio device is backed by a block device, the actual size of
the block device file doesn't represent the size as a virtio device.

Fixes firecracker-microvm#1316

Signed-off-by: Kazuyoshi Kato <[email protected]>
kzys added a commit to kzys/firecracker that referenced this issue Nov 6, 2019
@kzys
Add integration tests for firecracker-microvm#1316
706584d 
Signed-off-by: Kazuyoshi Kato <[email protected]>
kzys added a commit to kzys/firecracker that referenced this issue Nov 6, 2019
@kzys
vmm: fix the size of a virtio device, backed by a block device
22ef221 
When a virtio device is backed by a block device, the actual size of
the block device file doesn't represent the size as a virtio device.

Fixes firecracker-microvm#1316

Signed-off-by: Kazuyoshi Kato <[email protected]>
@iulianbarbu iulianbarbu assigned kzys and unassigned iulianbarbu Nov 6, 2019
kzys added a commit to kzys/firecracker that referenced this issue Nov 12, 2019
@kzys
vmm: fix the size of a virtio device, backed by a block device
776e20e 
When a virtio device is backed by a block device, the actual size of
the block device file doesn't represent the size as a virtio device.

Fixes firecracker-microvm#1316

Signed-off-by: Kazuyoshi Kato <[email protected]>
kzys added a commit to kzys/firecracker that referenced this issue Nov 12, 2019
@kzys
vmm: fix the size of a virtio device, backed by a block device
6a3ef2a 
When a virtio device is backed by a block device, the actual size of
the block device file doesn't represent the size as a virtio device.

Fixes firecracker-microvm#1316

Signed-off-by: Kazuyoshi Kato <[email protected]>
kzys added a commit to kzys/firecracker that referenced this issue Nov 14, 2019
@kzys
vmm: fix the size of a virtio device, backed by a block device
32c63f1 
When a virtio device is backed by a block device, the actual size of
the block device file doesn't represent the size as a virtio device.

Fixes firecracker-microvm#1316

Signed-off-by: Kazuyoshi Kato <[email protected]>
mi-yu pushed a commit to mi-yu/firecracker that referenced this issue Dec 3, 2019
@kzys @mi-yu
vmm: fix the size of a virtio device, backed by a block device
b6c6221 
When a virtio device is backed by a block device, the actual size of
the block device file doesn't represent the size as a virtio device.

Fixes firecracker-microvm#1316

Signed-off-by: Kazuyoshi Kato <[email protected]>
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