littlefs fs_mkdir failing with error -22 (Invalid argument)

I’ve been struggling with this all week now. I am trying to get littlefs to create a directory in /lfs but it fails with error -22. I was able to get it to work once, but now… nothing.

This is my code snippet:

...
        char dname[MAX_PATH_LEN];

	// create data directory if it doesn't exist
	printk("Creating data directory...\n");
	
        // STORE_FORWARD_DIR defined as "sfdata"
	snprintf(dname, sizeof(dname), "%s/%s", mp->mnt_point, STORE_FORWARD_DIR);

	int rc = fs_mkdir(dname);
	if (rc && rc != -EEXIST) {
		printk("  mkdir(%s) error -> rc=%d\n", dname, rc);
		return rc;
	} 
	printk("  mkdir(%s) SUCCESS -> rc=%d\n", dname, rc);
...

I’ve tried numerous variations of this but no luck. The one time I was able to create it the file system worked perfectly but then I decided to attempt a reset the file system by erasing the flash area. However this seemed to corrupt the flash device and I was not longer able to do anything with it. I assumed I wrecked the flash and ordered more boards assuming that was my problem.

On a brand new board, this still does not work and I am at a loss. Naturally there are other implementations I could choose that do not require a subdirectory, but I am more concerned that I am doing something fundamentally wrong and I don’t want to deploy devices with a critical fault so I really need to get something so basic working properly.

Has anyone tried this yet?

jaredwolff Thanks for the reply. I have tried CONFIG_APP_WIPE_STORAGE but it does not seem to work. After I execute flash_area_erase() the device still has all files and structure as it did before the erase and does not solve the problem I’m having. Also, is there a specific initialization or format process for littlefs?

Perhaps I’m not initializing it properly…

But that doesn’t make sense because I can create/write/open files all I want - onlymkdir fails.

jaredwolff

Yes, I have this working now. Thank you!

The flash erase is working properly now! Once I was able to do that I can now create directories without issue. To be honest, I don’t know what the root cause was but I suspect at some point, when I was playing around with having some file stuff in a thread, it got pre-empted and corrupted the filesystem somehow. I have no proof, but I had other issues using a thread for MQTT which failed randomly regardless of thread priority. Once I moved file and network handling back into main, my problems went away.

This was really painful and I don’t fully understand it, but at least I now have a fully working app with LTE-M (on Rogers in Canada), MQTT, store-forward, PCF85063A RTC datetime set from NTP, deep sleep with PCF85063A timer wake-up, external 5V boost converter, and a TeraBee distance sensor on UART. Good times!

Thanks for your help… I really love this board, you’ve done a great job with it.

Cheers