md raid: fix hang when stopping arrays with metadata through dm-raid #253
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![kpd-daemon[bot]](https://avatars.githubusercontent.com/u/162645851?s=80&v=4){kind=small}
When using device-mapper's dm-raid target, stopping a RAID array can cause the
system to hang under specific conditions.
This occurs when:
- A dm-raid managed device tree is suspended from top to bottom
(the top-level RAID device is suspended first, followed by its
underlying metadata and data devices)
- The top-level RAID device is then removed
The hang happens because removing the top-level device triggers md_stop() from the
dm-raid destructor. This function attempts to flush the write-intent bitmap, which
requires writing bitmap superblocks to the metadata sub-devices. However, since
these metadata devices are already suspended, the write operations cannot complete,
causing the system to hang.
Fix:
- Prevent bitmap flushing when md_stop() is called from dm-raid contexts
and avoid a quiescing/unquescing cycle which could also cause I/O
- Avoid any I/O operations that might occur during the quiesce/unquiesce process in md_stop()
This ensures that RAID array teardown can complete successfully even when the
underlying devices are in a suspended state.
Signed-off-by: Heinz Mauelshagen <[email protected]>
|
Upstream branch: c17fb54 |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Pull request for series with
subject: md raid: fix hang when stopping arrays with metadata through dm-raid
version: 1
url: https://patchwork.kernel.org/project/linux-raid/list/?series=1003842