Do'h! I almost forgot about LFS_O_TRUNC. If LFS_O_CREAT + LFS_O_SYNC
implies lfsr_file_sync, clearly LFS_O_TRUNC + LFS_O_SYNC should as well.
This changes lfsr_file_open to only imply lfsr_file_sync if any open
operation sets the unsync flag, which is the only case where
lfsr_file_sync would do anything anyways.
This does have a subtle change in behavior when LFS_O_CREAT + LFS_O_SYNC
+ LFS_O_DESYNC, in that the desync flag is only cleared if the file did
not exist before. But I think this is more expected than unconditionally
syncing.
Note this matches the behavior of lfsr_file_write, which does _not_
imply lfsr_file_sync if the write is size=0.
---
Also added better tests over lfsr_file_open + LFS_O_TRUNC, this flag
isn't very well tested...
Which found a bug!
We were incorrectly setting LFS_o_UNFLUSH when opening with LFS_O_TRUNC,
when we should have set LFS_o_UNSYNC. This caused littlefs to never
bother updating the file's metadata unless some other write comes along
(which is what usually follows LFS_O_TRUNC).
To help catch bugs like this, I added an assert to lfsr_file_flush that
unflushed files are always marked unsynced. A synced + unflushed file is
weird and should never happen.
---
Code changes minimal:
code stack ctx
before: 35820 2480 640
after: 35824 (+0.0%) 2480 (+0.0%) 640 (+0.0%)
Christopher Haster
7b81f01db4