lfs_alloc() blocks on full filesystem.

[ddomnik]

This issue is derived from this Espressif port: joltwallet/esp_littlefs#213 But I think it most likely fits better here.

Usually on a full filesystem littleFS returns from fwrite() within a few ms and prints:
E (2818207) esp_littlefs: ./managed_components/joltwallet__littlefs/src/littlefs/lfs.c:689:error: No more free space 0x48d

However, it could happen that the library gets "stuck" for a very long time (multiple seconds or even minutes - prob. depending on partition size). This happens exactly in this while loop. (The second while in lfs_alloc())

littlefs/lfs.c

Line 656 in d01280e

while (lfs->lookahead.next < lfs->lookahead.size) {

The problem is, that almost every program uses watchdogs. Espressifs default watchdog has a maximum of 60 seconds, which seems to be insufficient in rare cases and then resets the whole device. maximum wdt timeout

Maybe some experts know how to handle this issue.

Based on my current understanding of the issue, a very simple thought would be to give littleFs it's own watchdog that can be set. This allows to "catch" the issue on application level rather than system level.