md raid: fix hang when stopping arrays with metadata through dm-raid#253
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md raid: fix hang when stopping arrays with metadata through dm-raid#253kpd-daemon[bot] wants to merge 1 commit into
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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 <heinzm@redhat.com>
Author
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Upstream branch: c17fb54 |
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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