scoutfs/ReleaseNotes.md

Versity ScoutFS Release Notes

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v1.9
Oct 29, 2022

Fix VFS cached directory entry consistency verification that could cause spurious "no such file or directory" (ENOENT) errors from rename over NFS under certain conditions. The problem was only every with the consistency of in-memory cached dentry objects, persistent data was correct and eventual eviction of the bad cached objects would stop generating the errors.

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v1.8
Oct 18, 2022

Add support for Linux POSIX Access Control Lists, as described in acl(5). Mount options are added to enable ("acl") and disable ("noacl") support. The default is to support ACLs. ACLs are stored in the existing extended attribute scheme so adding support is does not require a format change.

Add options to control data extent preallocation. The default behavior does not change. The options can relax the limits on preallocation which will then trigger under more write patterns and increase the risk of preallocated space which is never used. The options are described in scoutfs(5).

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v1.7
Aug 26, 2022

• Fixed possible persistent errors moving freed data extents
  Fixed a case where the server could hit persistent errors trying to move a client's freed extents in one commit. The client had to free a large number of extents that occupied distant positions in the global free extent btree. Very large fragmented files could cause this. The server now moves the freed extents in multiple commits and can always ensure forward progress.

• Fixed possible persistent errors from freed duplicate extents
  Background orphan deletion wasn't properly synchronizing with foreground tasks deleting very large files. If a deletion took long enough then background deletion could also attempt to delete inode items while the deletion was making progress. This could create duplicate deletions of data extent items which causes the server to abort when it later discovers the duplicate extents as it merges free lists.

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v1.6
Jul 7, 2022

• Fix memory leaks in rare corner cases
  Analysis tools found a few corner cases that leaked small structures, generally around error handling or startup and shutdown.

• Add --skip-likely-huge scoutfs print command option
  Add an option to scoutfs print to reduce the size of the output so that it can be used to see system-wide metadata without being overwhelmed by file-level details.

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v1.5
Jun 21, 2022

• Fix persistent error during server startup
  Fixed a case where the server would always hit a consistent error on seartup, preventing the system from mounting. This required a rare but valid state across the clients.

• Fix a client hang that would lead to fencing
  The client module's use of in-kernel networking was missing annotation that could lead to communication hanging. The server would fence the client when it stopped communicating. This could be identified by the server fencing a client after it disconnected with no attempt by the client to reconnect.

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v1.4
May 6, 2022

• Fix possible client crash during server failover
  Fixed a narrow window during server failover and lock recovery that could cause a client mount to believe that it had an inconsistent item cache and panic. This required very specific lock state and messaging patterns between multiple mounts and multiple servers which made it unlikely to occur in the field.

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v1.3
Apr 7, 2022

• Fix rare server instability under heavy load
  Fixed a case of server instability under heavy load due to concurrent work fully exhausting metadata block allocation pools reserved for a single server transaction. This would cause brief interruption as the server shutdown and the next server started up and made progress as pending work was retried.

• Fix slow fencing preventing server startup
  If a server had to process many fence requests with a slow fencing mechanism it could be interrupted before it finished. The server now makes sure heartbeat messages are sent while it is making progress on fencing requests so that other quorum members don't interrupt the process.

• Performance improvement in getxattr and setxattr
  Kernel allocation patterns in the getxattr and setxattr implementations were causing significant contention between CPUs. Their allocation strategy was changed so that concurrent tasks can call these xattr methods without degrading performance.

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v1.2
Mar 14, 2022

• Fix deadlock between fallocate() and read() system calls
  Fixed a lock inversion that could cause two tasks to deadlock if they performed fallocate() and read() on a file at the same time. The deadlock was uninterruptible so the machine needed to be rebooted. This was relatively rare as fallocate() is usually used to prepare files before they're used.

• Fix instability from heavy file deletion workloads
  Fixed rare circumstances under which background file deletion cleanup tasks could try to delete a file while it is being deleted by another task. Heavy load across multiple nodes, either many files being deleted or large files being deleted, increased the chances of this happening. Heavy staging could cause this problem because staging can create many internal temporary files that need to be deleted.

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v1.1
Feb 4, 2022

• Add scoutfs(1) change-quorum-config command
  Add a change-quorum-config command to scoutfs(1) to change the quorum configuration stored in the metadata device while the file system is unmounted. This can be used to change the mounts that will participate in quorum and the IP addresses they use.

• Fix Rare Risk of Item Cache Corruption
  Code review found a rare potential source of item cache corruption. If this happened it would look as though deleted parts of the filesystem returned, but only at the time they were deleted. Old deleted items are not affected. This problem only affected the item cache, never persistent storage. Unmounting and remounting would drop the bad item cache and resync it with the correct persistent data.

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v1.0
Nov 8, 2021

• Initial Release
  Version 1.0 marks the first GA release.