The previous cleanup logic conflated two independent concerns into
SDLOG_MAX_SIZE: the maximum size of a single log file (rotation
trigger) AND the minimum free space to maintain. That was broken:
the 4095 MB default meant "keep 4 GB free", which over-cleaned on
large SD cards and was impossible to satisfy on small flash.
Disentangle the two:
- SDLOG_ROTATE (new, int %, default 90): maximum disk usage percentage.
Cleanup guarantees at least (100 - SDLOG_ROTATE)% free even during
writing of a new log file. Setting 0 disables space-based cleanup;
100 allows filling the disk completely.
- SDLOG_MAX_SIZE (default lowered from 4095 to 1024): pure max file
size. The value is added on top of the rotate-derived threshold as
headroom for the next file write, so the rotate guarantee holds
even mid-write.
- SDLOG_DIRS_MAX: removed. Directory count limits were confusing and
orthogonal to the space-management goal; free-space cleanup alone
covers the use case. Drop the param and all remaining overrides
(rc.board_defaults, rcS, rc.replay, 1002_standard_vtol.hil).
Cleanup threshold is now:
((100 - SDLOG_ROTATE)% of disk) + SDLOG_MAX_SIZE
Small-flash boards can override SDLOG_MAX_SIZE to get more retained
logs within the available space. kakuteh7v2 and airbrainh743 drop
their SDLOG_DIRS_MAX overrides accordingly.
Update docs/en/dev_log/logging.md with the new semantics and a
worked example for the typical 8 GB SD case.
Add an NSH command to format a device with littlefs, analogous to
mkfatfs for FAT filesystems. The command unmounts the mount point,
then remounts with forceformat to format and mount in one step.
Enable the command on boards that use littlefs as primary storage
(airbrainh743 and kakuteh7v2), and document it in the airbrainh743
flight controller page as a recovery procedure for a corrupted
flash filesystem.
Usage: mklittlefs /dev/mtd0 /fs/flash
Julian Oes