File System
The OpenHarmony LiteOS-M kernel supports File Allocation Table file system (FATFS) and LittleFS file systems. Like the OpenHarmony LiteOS-A kernel, the OpenHarmony LiteOS-M kernel provides POSIX over the virtual file system (VFS) to ensure interface consistency. However, the VFS of the LiteOS-M kernel is light due to insufficient resources and does not provide advanced functions (such as pagecache). Therefore, the VFS of the LiteOS-M kernel implements only API standardization and adaptation. The file systems handle specific transactions. The following table lists the functions supported by the file systems.
Table 1 Function list
Function
|
API
|
Description
|
FATFS
|
LITTLEFS
|
|---|
File management
|
open
|
Opens a file.
|
Supported
|
Supported
|
close
|
Closes a file.
|
Supported
|
Supported
|
read
|
Reads a file.
|
Supported
|
Supported
|
write
|
Writes data to a file.
|
Supported
|
Supported
|
lseek
|
Sets the file offset.
|
Supported
|
Supported
|
unlink
|
Deletes a file.
|
Supported
|
Supported
|
rename
|
Renames a file.
|
Supported
|
Supported
|
fstat
|
Obtains file information based on the file handle.
|
Supported
|
Supported
|
stat
|
Obtains file information based on the file path name.
|
Supported
|
Supported
|
fsync
|
Saves file updates to a storage device.
|
Supported
|
Supported
|
Directory management
|
mkdir
|
Creates a directory.
|
Supported
|
Supported
|
opendir
|
Opens a directory.
|
Supported
|
Supported
|
readdir
|
Reads the content of a directory.
|
Supported
|
Supported
|
closedir
|
Closes a directory.
|
Supported
|
Supported
|
rmdir
|
Deletes a directory.
|
Supported
|
Supported
|
Partition management
|
mount
|
Mounts a partition.
|
Supported
|
Supported
|
umount
|
Unmounts a partition.
|
Supported
|
Supported
|
umount2
|
Forcibly unmounts a partition using the MNT_FORCE parameter.
|
Supported
|
Not supported
|
statfs
|
Obtains partition information.
|
Supported
|
Not supported
|