What is F2FS?

F2FS is the most commonly used log-structured file system in Linux. It supports flash-friendly features such as adaptive logging, multi-head logging, fsync acceleration, and node address translation. For more information see: https://www.usenix.org/conference/fast15/technical-sessions/presentation/lee

Major Release

1st release (Apr-06-2021)

• Features: mkfs, mount/umount, read, write, rmdir, mkdir, rename, fsync, lseek, link, unlink
• Remarks

• Fuchsia base code ; Thu Mar 11 08:53:24 2021 Prashanth Swaminathan,76a08ad1474 [speak] Migrate to new component templates
• There is no cache. Every request is handled as a synchronous operation.
• fsync() triggers checkpointing
• lock granularity: file operation
• LFS is used for block allocation by default, and IPU is forced when the number of free sections is below 50%.
• no background/foreground gc
• disable the roll-forward recovery
• 6 active logs
• disable the ext-identify feature
• block allocation: LFS, IPU
• fsck do nothing, but it returns true
• no discard

2nd release (May-28-2021)

• Features: truncate, ssr, fsync, recovery
• Remarks

• Fuchsia base code ; Thu May 20 07:25:45 2021 Yilong Li, 02c0dfff0fdb
• support the roll-forward recovery and file level fsync()
• block allocation: LFS, IPU, SSR
• truncate

3rd release (June-25-2021)

• Features: fsck, mount option, mkfs option
• all fs-tests and large-fs-tests passed
• Remarks

• fsck (base: 7f35b548d4b)
• support the ext-identify feature
• support discard

4th release (July-30-2021)

• Features: vnode cache, inline dentry
• unit test coverage

5th release (August-27-2021)

• Features: dentry cache
• Landing
• Linux compatibility test coverage

6th release (September-30-2021 ~)

• Features: gc, node cache, pager support, mmap, wb, readahead, ... (as new fuchsia features coming)
• stress test coverage
• performance test

How to build

$ fx set core.x64 --with-base //bundles:tools --with-base //bundles:tests --with-base third_party/f2fs
(see third_party/f2fs/test_files/README.md for test)