Linux Plumbers Conference 2021

Session

File Systems MC

21 Sept 2021, 07:00

Description

The File system microconference focuses on a variety of file system related topics in the Linux ecosystem. Interesting topics about enabling new features in the file system ecosystem as a whole, interface improvements, interesting work being done, really anything related to file systems and their use in general. Often times file system people create interfaces that are slow to be used, or get used in new and interesting ways that we did not think about initially. Having these discussions with the larger community will help us work towards more complete solutions and happier developers and users overall.

Presentation materials

lpc-2021-filesystem-mc.pdf

project_id.pdf

94. Efficient buffered I/O

Matthew Wilcox (Oracle)

21/09/2021, 07:00

Files are currently managed in PAGE_SIZE units. As DRAM and storage capacities increase, the overhead of managing all these pages becomes more significant. The memory folio patchset lets us cache files in larger units.

In this session, we shall discuss:

• Filesystem changes needed to work with folios instead of pages
• Converting from buffer_heads to iomap
• Using the netfs API
  ...

266. Idmapped Mounts

Mr Christian Brauner

21/09/2021, 07:30

File ownership is a global property on most systems that have a uid and gid concept. On POSIXy systems the chown*() syscall family allows to change the owner of a file or directory. If the ownership of a file is changed it will be changed globally affecting each user on the systems equally. But various use-cases exist where this can be problematic:
- Portable home directories that are used on...

102. Atomic file writes: Who really wants this?

Darrick Wong (Oracle)

21/09/2021, 08:30

I would like to chair a discussion at LPC to discuss atomic file writes for userspace applications. Do we want to expose such a capability to programs, and if so, how?

I propose filesystem implementations provide a general-purpose interface in software. As proposed, the FIEXCHANGE_RANGE system call requires the ability to exchange the contents of two files, with a promise that once we...

218. File System Shrink

Allison Henderson

21/09/2021, 09:00

File system shrink allows a file system to be reduced in size by some specified size blocks as long as the file system has enough unallocated space to do so. This operation is currently unsupported in xfs. Though a file system can be backed up and recreated in smaller sizes, this is not functionally the same as an in place resize. Implementing this feature is costly in terms of developer...

104. Bad Storage vs. Filesystems

Darrick Wong (Oracle)

21/09/2021, 09:45

The focus of this session is on mitigating the effects of unreliable storage devices. This author works at a cloud vendor (as is fashionable now), and one of the large story arcs of the past few years has been that storage devices do not seem as reliable as we thought even a few years ago.

Specifically, I've observed that as the world moves from direct-attached spinning rust to...

103. XFS Roadmap Planning

Darrick Wong (Oracle)

21/09/2021, 10:30

This is a BOF for people to get together to discuss unresolved issues in the community and to talk about the roadmap for new feature development and ongoing technical debt payoff. We have not had such a forum since LSFMM in 2018.

Roadmap topics include:

• Shrink
• Online Repair
• Reflink and Reverse Mapping on the Realtime Device
• The future of RT and Quota
• Parent Pointers
  ...

13. File system microconference

A microconference to cover the variety of file system related topics in the Linux ecosystem. Interesting topics about enabling new features in the file system ecosystem as a whole, interface improvements, interesting work being done, really anything related to file systems and their use in general. Often times file system people create interfaces that are slow to be used, or get used in new...