F2FS (Flash-Friendly File System) is a file system intended for NAND-based flash memory equipped with Flash Translation Layer. Unlike JFFS or UBIFS it relies on FTL to handle write distribution. It is supported from kernel 3.8 onwards.
Creating a F2FS file system
In order to create a F2FS file system, install .
Create the file system:
# mkfs.f2fs -l mylabel /dev/sdxY
/dev/sdxY is the target volume to format in F2FS. See for all available options.
If you want to use compression, you must provide
compression options at filesystem creation.
# mkfs.f2fs -l mylabel -O extra_attr,compression /dev/sdxY
When mounting the filesystem, you will have to specify
compress_extension=txt will cause all txt files to be compressed by default.
In order to tell F2FS to compress a file or a directory, use :
$ chattr -R +c [FOLDER]
Inode and superblock checksums
Some filesystem options can be used to help
f2fs.fsck do its job in case of a corrupted filesystem. These are especially useful if you use filesystem compression. Theses options are
sb_checksum. Add them in the options list given to
mkfs.f2fs when creating your partition.
If enabled, these options allow
f2fs.fsck to easily detect corrupted inodes and in some cases it can fix them.
File-based encryption support
Since Linux 4.2, F2FS natively supports file encryption. Encryption is applied at the directory level, and different directories can use different encryption keys. This is different from both dm-crypt, which is block-device level encryption, and from eCryptfs, which is a stacked cryptographic filesystem. To use F2FS's native encryption support, see the fscrypt article. Create the file system with
# mkfs.f2fs -l mylabel -O encrypt /dev/sdxY
or add encryption capability at a later time with
fsck.f2fs -O encrypt /dev/sdxY.
Mounting a F2FS file system
The file system can then be mounted manually or via other mechanisms:
# mount /dev/sdxY /mnt/foo
Implementation of discard
By default, F2FS partitions are mounted using a hybrid TRIM mode which behaves as continuous TRIM. This implementation creates asynchronous discard threads to alleviate long discarding latency among RW IOs. It keeps candidates in memory, and the thread issues them in idle time . As a result of this, users wanting periodic TRIM will need to implicitly set the
nodiscard mount option in
/etc/fstab or pass it to mount if mounting manually.
Checking and repair
Checking and repairs to f2fs file systems are accomplished with
fsck.f2fs provided by . See for available switches.
Grow an F2FS file system
When the filesystem is unmounted, it can be grown if the partition is expanded. Shrinking is not currently supported.
First use a partition tool to resize the partition: for example, suppose the output of the
parted console for your disk is the following:
Number Start End Size File system Name Flag 1 1049kB 106MB 105MB fat32 EFI system partition boot, esp 2 106MB 11,0GB 10,9GB ext4 3 11,0GB 12,3GB 1322MB f2fs 4 31,0GB 31,3GB 261MB ext4
To resize the
f2fs partition to occupy all the space up to the fourth one, just give
resizepart 3 31GB and
exit. You can now expand the filesystem to fill the new partition using:
# resize.f2fs /dev/sdxY
/dev/sdxY is the target F2FS volume to grow. See for supported options.
/dev/disk/by-partuuid/) might change, but the filesystem UUID (seen in
/dev/disk/by-uuid/) should stay the same.
Long running fsck delays boot
If the kernel version has changed between boots, the fsck.f2fs utility will perform a full file system check which will take longer to finish.
This may be mitigated in the future thanks to a recent commit