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bmap: Initial scaffolding for on-disk block map

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This is pretty exploratory work, so I'm going to try to be less thorough
in commit messages until the dust settles.

---

New tag for gbmapdelta:

  LFS3_TAG_GBMAPDELTA   0x0104  v--- ---1 ---- -1rr

New tags for in-bmap block types:

  LFS3_TAG_BMRANGE      0x033u  v--- --11 --11 uuuu
  LFS3_TAG_BMFREE       0x0330  v--- --11 --11 ----
  LFS3_TAG_BMINFLIGHT   0x0331  v--- --11 --11 ---1
  LFS3_TAG_BMINUSE      0x0332  v--- --11 --11 --1-
  LFS3_TAG_BMBAD        0x0333  v--- --11 --11 --11
  LFS3_TAG_BMERASED     0x0334  v--- --11 --11 -1--

New gstate decoding for gbmap:

  .---+- -+- -+- -+- -. cursor: 1 leb128  <=5 bytes
  | cursor            | known:  1 leb128  <=5 bytes
  +---+- -+- -+- -+- -+ block:  1 leb128  <=5 bytes
  | known             | trunk:  1 leb128  <=4 bytes
  +---+- -+- -+- -+- -+ cksum:  1 le32    4 bytes
  | block             | total:            23 bytes
  +---+- -+- -+- -+- -'
  | trunk         |
  +---+- -+- -+- -+
  |     cksum     |
  '---+---+---+---'

New bmap node revdbg string:

  vvv---- -111111- -11---1- -11---1-  (62 62 7e v0  bb~r)  bmap node

New mount/format/info flags (still unsure about these):

  LFS3_M_BMAPMODE     0x03000000  On-disk block map mode
  LFS3_M_BMAPNONE     0x00000000  Don't use the bmap
  LFS3_M_BMAPCACHE    0x01000000  Use the bmap to cache lookahead scans
  LFS3_M_BMAPSLOW     0x02000000  Use the slow bmap algorithm
  LFS3_M_BMAPFAST     0x03000000  Use the fast bmap algorithm

New gbmap wcompat flag:

  LFS3_WCOMPAT_GBMAP  0x00002000  Global block-map in use
This commit is contained in:
Christopher Haster
2025-07-23 15:32:35 -05:00
parent 238dbc705d
commit 88180b6081
13 changed files with 755 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files
runners/bench_runner.h
+10 -1
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@@ -114,6 +114,7 @@ void bench_permutation(size_t i, uint32_t *buffer, size_t size);
BENCH_DEFINE(PCACHE_SIZE, LFS3_MAX(16, PROG_SIZE) ) \
BENCH_DEFINE(FILE_CACHE_SIZE, 16 ) \
BENCH_DEFINE(LOOKAHEAD_SIZE, 16 ) \
BENCH_DEFINE(TREEDIFF_SIZE, 16 ) \
BENCH_DEFINE(GC_FLAGS, 0 ) \
BENCH_DEFINE(GC_STEPS, 0 ) \
BENCH_DEFINE(GC_COMPACT_THRESH, 0 ) \
@@ -144,14 +145,22 @@ void bench_permutation(size_t i, uint32_t *buffer, size_t size);
.pcache_size = PCACHE_SIZE, \
.file_cache_size = FILE_CACHE_SIZE, \
.lookahead_size = LOOKAHEAD_SIZE, \
BENCH_BMAP_CFG \
BENCH_GC_CFG \
.gc_compact_thresh = GC_COMPACT_THRESH, \
.inline_size = INLINE_SIZE, \
.fragment_size = FRAGMENT_SIZE, \
.crystal_thresh = CRYSTAL_THRESH,
#ifdef LFS3_BMAP
#define BENCH_BMAP_CFG \
.treediff_size = TREEDIFF_SIZE,
#else
#define BENCH_BMAP_CFG
#endif
#ifdef LFS3_GC
#define BENCH_GC_CFG \
#define BENCH_GC_CFG \
.gc_flags = GC_FLAGS, \
.gc_steps = GC_STEPS,
#else