Littlefs thread safe

RE: Littlefs thread safe

Etienne D. — Wed, 20 Dec 2023 10:08:05 GMT

Hello, given your advice to use semaphores at the flash level, are you suggesting that fs operations are generally not thread safe?

As far as I understand in littlefs_fs.c there is a mutex around the littlefs API calls. So operating on different files from different threads should be fine, right? Only writing to the same file from different threads could lead to issues. Or am I missing something here?

RE: Littlefs thread safe

SoukTi — Wed, 25 Oct 2023 13:26:34 GMT

Thanks. You can mark this once as solved

RE: Littlefs thread safe

Kenneth — Wed, 25 Oct 2023 10:55:16 GMT

[quote user="SoukTi"] so you suggest to do the locks at the user code side[/quote]

Yes, or use work queue.

Kenneth

RE: Littlefs thread safe

SoukTi — Wed, 25 Oct 2023 09:52:04 GMT

Thanks, so you suggest to do the locks at the user code side, not in the ncs littlefs_fs.c file. I will see if its possible to add them there. We have lots of positions in the code that write I'll need to add lock to each of them.

RE: Littlefs thread safe

Kenneth — Wed, 25 Oct 2023 08:01:32 GMT

Hello,

Depending on who you ask I guess you will get different suggestions, but I am thinking two alternatives, either:

1. Maybe use work queue to run all flash operation after each other:
https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/lessons/lesson-7-multithreaded-applications/topic/exercise-3-7/

2. Use semaphore, e.g. at any time you want to write to flash: take a semaphore, write to flash, release semaphore:
https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/lessons/lesson-8-thread-synchronization/topic/mutexes/

Kenneth