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Auke Kok
9e35e4ed0d
A node only needs to be fenced once, but scoutfs_fence_start() can be called for the same rid more than once. When a new leader starts it fences the previous leader as it removes it from the quorum (quorum_block_leader), and that same rid can also be a mounted client that then fails to recover within the timeout (client_recovery). The second fence call collides on that name, sysfs returns -EEXIST, and the error is propagated to fence_pending_recov_worker() which treats any error as fatal and shuts the server down. On the next mount a new leader hits the same stale set and the same collision, so the filesystem can never finish recovery. Jun 15 09:22:35 kernel: scoutfs f.000000.r.222222: fencing previous leader f.000000.r.111111 at term 183942 in slot 3 with address x.x.x.x:6000 Jun 15 09:22:36 scoutfs-fenced[9194]: [2026-06-15 09:22:36.588037842] server f.000000.r.222222 fencing rid 1111111111111111 at IP x.x.x.x for quorum_block_leader Jun 15 09:23:09 kernel: scoutfs f.000000.r.222222 error: 30000 ms recovery timeout expired for client rid 1111111111111111, fencing Jun 15 09:23:09 kernel: sysfs: cannot create duplicate filename '/fs/scoutfs/f.000000.r.222222/fence/1111111111111111' Jun 15 09:23:09 kernel: scoutfs f.000000.r.222222 error: fence returned err -17, shutting down server The reclaim path keys off the rid, not the reason, so one pending fence covers both needs. Reserve the rid by checking for an existing entry and adding the new pending_fence to the list under the same lock; a concurrent caller for the same rid then sees it and returns success without touching sysfs. The sysfs create runs after the list insert, so any remaining -EEXIST reflects stale on-disk state and is left to shut the server down rather than masked. Restructure the function to a single exit: track on-list with a bool, NULL the local on success, and let the out path remove from the list and free if a failure left the entry behind. Signed-off-by: Auke Kok <auke.kok@versity.com>
Introduction
scoutfs is a clustered in-kernel Linux filesystem designed to support large archival systems. It features additional interfaces and metadata so that archive agents can perform their maintenance workflows without walking all the files in the namespace. Its cluster support lets deployments add nodes to satisfy archival tier bandwidth targets.
The design goal is to reach file populations in the trillions, with the archival bandwidth to match, while remaining operational and responsive.
Highlights of the design and implementation include:
- Fully consistent POSIX semantics between nodes
- Atomic transactions to maintain consistent persistent structures
- Integrated archival metadata replaces syncing to external databases
- Dynamic seperation of resources lets nodes write in parallel
- 64bit throughout; no limits on file or directory sizes or counts
- Open GPLv2 implementation
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