TLDR: Replaced lfs3_file_ckmeta/ckdata and lfs3_fs_ckmeta/ckdata with
flag based ck functions:
- lfs3_file_ckmeta -> lfs3_file_ck + LFS3_CK_CKMETA
- lfs3_file_ckdata -> lfs3_file_ck + LFS3_CK_CKDATA
- lfs3_fs_ckmeta -> lfs3_fs_ck + LFS3_FSCK_CKMETA
- lfs3_fs_ckdata -> lfs3_fs_ck + LFS3_FSCK_CKDATA
Note lfs3_fs_ck is equivalent to lfs3_fs_gc, but:
1. Performs the work in one call (equivalent to littlefs2's lfs2_fs_gc)
2. Takes flags at call time (like lfs3_mount) instead of cfg time (like
lfs3_fs_gc)
3. Avoids the constant RAM necessary to track incremental GC state
---
Motivation:
I've been thinking: It's a bit weird that users are able to one-shot
janitorial work in lfs3_mount, but there's no equivalent function after
the filesystem is mounted.
Originally this is what lfs3_fs_gc was for, but after adding support for
incremental GC, it made sense to hide lfs3_fs_gc behind the opt-in
LFS3_GC ifdef due to the extra (ironically non-gc-able) state.
In theory lfs3_trv_t fills a bit of the gap, but, without the internal
i_flag handling and traversal restarts, it's a bit hard to use. And
basically requires duplicating said log, which we need anyways for
lfs3_mount!
So ideally we'd add an explicit one-shot GC function, but now lfs3_fs_gc
is taken.
While thinking about alternative names, I realized we can just call this
lfs3_fs_ck and completely replace lfs3_fs_ckmeta/ckdata.
This has some extra benefits:
- Avoids an explosion of ckmeta/ckdata/repairmeta/repairdata functions
- Discourages redundant traversals that could accomplish more work
- Makes it less confusing that ckdata implies ckmeta
---
I also tweaked lfs3_file_ck to match, but note that lfs3_file_ck is
internally very different from lfs3_fs_ck. For one, lfs3_file_ck only
supports "actual" check flags (LFS3_CK_*) vs all gc flags (LFS3_FSCK_*):
lfs3_file_ck:
LFS3_CK_CKMETA 0x00010000 Check metadata checksums
LFS3_CK_CKDATA 0x00020000 Check metadata + data checksums
LFS3_CK_REPAIRMETA* 0x00040000 Repair metadata blocks
LFS3_CK_REPAIRDATA* 0x00080000 Repair metadata + data blocks
* Planned
lfs3_fs_ck:
LFS3_FSCK_MKCONSISTENT 0x00000800 Make the filesystem consistent
LFS3_FSCK_LOOKAHEAD 0x00001000 Repopulate lookahead buffer
LFS3_FSCK_LOOKGBMAP 0x00002000 Repopulate the gbmap
LFS3_FSCK_PREERASE* 0x00004000 Pre-erase unused blocks
LFS3_FSCK_COMPACTMETA 0x00008000 Compact metadata logs
LFS3_FSCK_CKMETA 0x00010000 Check metadata checksums
LFS3_FSCK_CKDATA 0x00020000 Check metadata + data checksums
LFS3_FSCK_REPAIRMETA* 0x00040000 Repair metadata blocks
LFS3_FSCK_REPAIRDATA* 0x00080000 Repair metadata + data blocks
* Planned
As a plus, this also saves a bit of code:
code stack ctx
before: 35968 2280 660
after: 35924 (-0.1%) 2280 (+0.0%) 660 (+0.0%)
code stack ctx
gbmap before: 38828 2296 772
gbmap after: 38812 (-0.0%) 2296 (+0.0%) 772 (+0.0%)
Christopher Haster
5c0cebb00b