Linux Kernel Daily: VFS Subsystem Fixes for Release Candidate 8

Transcript

Good morning, this is Linux Kernel Daily for January 27th, 2026.

Today brings one significant merge from Linus Torvalds, pulling VFS fixes from Christian Brauner for kernel 6.19 release candidate 8. This substantial merge addresses multiple critical issues across the virtual file system layer.

The merge tackles several key areas. FUSE receives the most attention with fixes for a buggy conversion in fuse_reverse_inval_entry, improvements to stale dentry cleanup to prevent use-after-free conditions, and better handling of hash bucket scanning. The fixes also address a race condition when disposing stale dentries and implement private naming for FUSE hash sizes.

Directory delegation handling sees widespread improvements across multiple filesystems. NFS, Ceph, GFS2, 9P, and SMB client implementations now properly disallow delegation requests for directories by setting simple_nosetlease.

The writeback subsystem receives performance and correctness fixes. The merge resolves a 100% CPU usage issue when dirtytime_expire_interval is set to zero, implements proper scheduling of dirty time work only when intervals are non-zero, and switches to rounded_jiffies_interval for better timer efficiency.

Additional fixes include requiring opt-in for readdir flag bits outside the standard mask, adding return value checking for sb_set_blocksize in romfs, and ensuring batched folios remain stable in iomap operations.

Fifteen files were modified across the Documentation, filesystem implementations, and core VFS code, indicating the broad scope of these stability improvements.

What's next: With release candidate 8 fixes now merged, expect continued focus on stability improvements as the 6.19 kernel approaches final release. Additional subsystem maintainers may submit last-minute critical fixes.

That's your Linux Kernel Daily update. I'm your host, we'll see you tomorrow.