- nit: Moving brace to end of if statement line for consistency
- mount: add more debug info per CR
- Fix compiler error from extra parentheses
- Fix superblock typo
The basic idea is simple, if we seek to a position in the currently
loaded cache, don't flush the cache. Notably this ensures that seek is
always as fast or faster than just reading the data.
This is a bit tricky since we need to check that our new block and
offset match the cache, fortunately we can skip the block check by
reevaluating the block index for both the current and new positions.
Note this only works whene reading, for writing we need to always flush
the cache, or else we will lose the pending write data.
Interestingly this was introduced by two different PRs which were not tested
together until pre-release testing:
- Fix lfs_file_seek doesn't update cache properties correctly
- Fix compiler warnings when LFS_READONLY defined
BUG CASE:Assume there are 6 blocks in littlefs, block 0,1,2,3 already allocated. 0 has a tail pair of {2, 3}. Now we try to write more into 0.
When writing to block 0, we will split(FIRST SPLIT), thus allocate block 4 and 5. Up to now , everything is as expected.
Then we will try to commit in block 4, during which split(SECOND SPLIT) is triggered again(In our case, some files are large, some are small, one split may not be enough). Still as expected now.
BUG happens when we try to alloc a new block pair for the second split:
As lookahead buffer reaches the end , a new lookahead buffer will be generated from flash content, and block 4, 5 are unused blocks in the new lookahead buffer because they are not programed yet. HOWEVER, block 4,5 should be occupied in the first split!!!!! The result is block 4,5 are allocated again(This is where things are getting wrong).
commit ce2c01f results in this bug. In the commit, a lfs_alloc_ack is inserted in lfs_dir_split, which will cause split to reset lfs->free.ack to block count.
In summary, this problem exists after 2.1.3.
Solution: don't call lfs_alloc_ack in lfs_dir_split.
When the on-disk block size doesn't match the config block size, it is
possible to get file corruption. For instance, if the num blocks was
0x200 and we re-mount with 0x100 files could be corrupt.
If we re-mount with a larger number of blocks things should be safer,
but could be handled with a resize option or perhaps a mount flag to
ignore this parameter.
lfs_mdir_isopen goes unused if asserts are disabled, and this caused an
"unused function" warning on Clang (curiously not on GCC since the
function was static inline, commonly used for header-only functions).
Also removed "inline" from the lfs_mdir_* functions as these involve
linked-list operations and really shouldn't be inlined. And since they
are static, inlining should occur automatically if there is a benefit.
Found by dpgeorge
This was caused by the new lfs_file_rawseek optimization that can skip
flushing when calculated file->pos is unchanged combined with an
implicit expectation in lfs_file_truncate that lfs_file_rawseek
unconditionally sets file->pos.
Because of this assumption, lfs_file_truncate could leave file->pos in
an outdated state while changing the internal file metadata. Humorously,
this was always gauranteed to trigger the skip in lfs_file_rawseek when
we try to restore the file->pos, leaving the file->cache used to do the
CTZ skip-list lookup in a potentially bad state.
The easiest fix is to just update file->pos correctly. Note we don't
want to explicitly flush since we can leverage the same noop
optimization if we truncate to the file position. Which I've added a
test for.
Mostly taken from .travis.yml, biggest changes were around how to get
the status updates to work.
We can't use a token on PRs the same way we could in Travis, so instead
we use a second workflow that checks every pull request for "status"
artifacts, and create the actual statuses in the "workflow_run" event,
where we have full access to repo secrets.
After a bit of tweaking in 9dde5c7 to write out all superblocks
during lfs_format, additional writes were added after the sanity
checking normally done at the end.
This turned out to be a problem when porting littlefs, as it makes it
easy for addressing issues to not get caught during lfs_format.
Found by marekr, tristanclare94, and mjs513
We have seen poor read performance on NAND flashes with 128kB blocks.
The root cause is inline files having to traverse many sets of metadata
pairs inside the current block before being fully reconstructed. Simply
disabling inline files is not enough, as the metadata will still fill up
the block and eventually need to be compacted.
By allowing configuration of how much size metadata takes up, along with
limiting (or disabling) inline file size, we achieve read performance
improvements on an order of magnitude.
This indirectly solves an issue with lfs_file_rawclose asserting
when lfs_file_opencfg errors since appending to the mlist occurs
after open. It also may speed up some of the internal operations such as
the lfs_file_write used to resolve unflushed data.
The idea behind adopting mlist over flags is that realistically it's
unlikely for the user to open a significant number of files (enough for
big O to kick in). That being said, moving the mlist asserts into the
API wrappers does protect some of the internal operations from scaling
based on the number of open files.
This removes quite a bit of extra code needed to entertwine the
LFS_TRACE calls into the original funcions.
Also changed temporary return type to match API declaration where
necessary.
- Stayed on non-system include for lfs_util.h for now
- Named internal functions "lfs_functionraw"
- Merged lfs_fs_traverseraw
- Added LFS_LOCK/UNLOCK macros
- Changed LFS_THREADSAFE from 1/0 to defined/undefined to
match LFS_READONLY
- expand functions
- add comment
- rename functions
- fix locking issue in format and mount
- use global include
- fix ac6 linker issue
- use the global config file
- address review comments
- minor cleanup
- minor cleanup
- review comments
- undef unavailable function declarations altogether
- even less code, assert on write attempts
- remove LFS_O_WRONLY and other flags when compiling with LFS_READONLY
- do not annotate #endif, as requested
- move ifdef before comments blocks, rework dangling opening bracket
- ifdef file flags that are not needed in read-only mode
- slight refactor
- ifdef LFS_F_ERRED out as well
Previously we only bumped the revision count if an eviction would occur
immediately (and possibly corrupt littlefs). This works, but does risk
an unoptimal superblock size if an almost-exhausted superblock was
allocated during lfs_format.
As pointed out by tim-nordell-nimbelink, we can align the revision count
to maximize the number of block cycles without breaking the existing
requirements of increasing revision counts.
As an added benefit, littlefs's wear-leveling should behave more
consistently after this change.
