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bmap: Added initial gbatc interactions, up until out-of-known or remount

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This only works immediately after format, and only for one pass of the
disk, but it's a good way to test bmap lookups/allocation without
worrying about more complicated filesystem-wide interactions.
This commit is contained in:
Christopher Haster
2025-07-24 23:41:02 -05:00
parent 357526e775
commit 98f016b07e
3 changed files with 128 additions and 6 deletions
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lfs3.c
+115 -4
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@@ -7852,7 +7852,7 @@ static int lfs3_fs_consumegdelta(lfs3_t *lfs3, const lfs3_mdir_t *mdir) {
#ifdef LFS3_BMAP
tag = lfs3_rbyd_lookup(lfs3, &mdir->r, -1, LFS3_TAG_GBMAPDELTA,
&data);
if (tag < 0 && tag != LFS3_ERR_NOENT) {
if (tag != LFS3_ERR_NOENT) {
uint8_t gbmapdelta[LFS3_GBMAP_DSIZE];
lfs3_ssize_t d = lfs3_data_read(lfs3, &data,
gbmapdelta, LFS3_GBMAP_DSIZE);
@@ -10744,6 +10744,8 @@ static inline lfs3_size_t lfs3_graft_count(lfs3_size_t graft_count);
// allocate a block
#if !defined(LFS3_RDONLY) && !defined(LFS3_2BONLY)
static lfs3_sblock_t lfs3_alloc(lfs3_t *lfs3, uint32_t flags) {
//// bmap none algorithm ////
#ifndef LFS3_BMAP
while (true) {
// scan our lookahead buffer for free blocks
lfs3_sblock_t block = lfs3_alloc_findfree(lfs3);
@@ -10832,6 +10834,93 @@ static lfs3_sblock_t lfs3_alloc(lfs3_t *lfs3, uint32_t flags) {
// mark anything not seen as free
lfs3_alloc_markfree(lfs3);
}
//// bmap fast algorithm ////
#else
while (true) {
alloc:;
// found a free block?
if (lfs3->bmap.free > 0) {
lfs3_block_t block = lfs3->bmap.cursor;
lfs3->bmap.cursor = (lfs3->bmap.cursor + 1) % lfs3->block_count;
lfs3->bmap.free -= 1;
lfs3->bmap.known -= 1;
lfs3->lookahead.ckpoint -= 1;
// we should never alloc blocks {0,1}
LFS3_ASSERT(block != 0 && block != 1);
// erase requested?
if (lfs3_alloc_iserase(flags)) {
int err = lfs3_bd_erase(lfs3, block);
if (err) {
// bad erase? try another block
if (err == LFS3_ERR_CORRUPT) {
continue;
}
return err;
}
}
#ifdef LFS3_DBGALLOCS
LFS3_DEBUG("Allocated block 0x%"PRIx32", "
"bmap %"PRId32"/%"PRId32"/%"PRId32"/%"PRId32,
block,
lfs3->bmap.free,
lfs3->bmap.known,
lfs3->lookahead.ckpoint,
lfs3->cfg->block_count);
#endif
return block;
}
// search for a range of free blocks in our block atc
while (lfs3->bmap.known > 0
&& lfs3->lookahead.ckpoint > 0) {
lfs3_bid_t bid;
lfs3_stag_t tag = lfs3_btree_lookupnext(lfs3, &lfs3->bmap.gbatc,
lfs3->bmap.cursor,
&bid, NULL, NULL);
if (tag < 0) {
return tag;
}
lfs3_block_t d = lfs3_min(
(bid+1) - lfs3->bmap.cursor,
lfs3_min(lfs3->bmap.known, lfs3->lookahead.ckpoint));
// found free range?
if (tag == LFS3_TAG_BMFREE) {
lfs3->bmap.free = d;
goto alloc;
}
// keep searching...
lfs3->bmap.cursor = (lfs3->bmap.cursor + d) % lfs3->block_count;
lfs3->bmap.known -= d;
lfs3->lookahead.ckpoint -= d;
}
// in order to keep our block allocator from spinning forever when our
// filesystem is full, we mark points where there are no in-flight
// allocations with a checkpoint before starting a set of allocations
//
// if we've looked at all blocks since the last checkpoint, we report
// the filesystem as out of storage
//
if (lfs3->lookahead.ckpoint <= 0) {
LFS3_ERROR("No more free space "
"(bmap %"PRId32"/%"PRId32"/%"PRId32"/%"PRId32")",
lfs3->bmap.free,
lfs3->bmap.known,
lfs3->lookahead.ckpoint,
lfs3->cfg->block_count);
return LFS3_ERR_NOSPC;
}
// TODO rebuild atc based on in-flight blocks
LFS3_UNREACHABLE();
}
#endif
}
#endif
@@ -14868,6 +14957,9 @@ static int lfs3_init(lfs3_t *lfs3, uint32_t flags,
lfs3->graft = NULL;
lfs3->graft_count = 0;
// TODO are these zeros accomplished by flushgdelta in mountinited?
// should the flushgdelta be dropped?
// zero gstate
lfs3->gcksum = 0;
#ifndef LFS3_RDONLY
@@ -14882,6 +14974,19 @@ static int lfs3_init(lfs3_t *lfs3, uint32_t flags,
lfs3_memset(lfs3->grm_d, 0, LFS3_GRM_DSIZE);
#endif
// setup other global bmap state
// TODO is this actually needed?
#ifdef LFS3_BMAP
lfs3_btree_init(&lfs3->gbmap.b);
lfs3->gbmap.cursor = 0;
lfs3->gbmap.known = 0;
lfs3_btree_init(&lfs3->bmap.gbatc);
lfs3->bmap.known = 0;
lfs3->bmap.free = 0;
lfs3_memset(lfs3->gbmap_p, 0, LFS3_GBMAP_DSIZE);
lfs3_memset(lfs3->gbmap_d, 0, LFS3_GBMAP_DSIZE);
#endif
return 0;
failed:;
@@ -15450,16 +15555,22 @@ static int lfs3_mountinited(lfs3_t *lfs3) {
lfs3_dbgmrid(lfs3, lfs3->grm.queue[0]));
}
// decode the global block-map
//
// this one is a bit less exciting
#ifdef LFS3_BMAP
// decode the global block-map
err = lfs3_data_readgbmap(lfs3,
&LFS3_DATA_BUF(lfs3->gbmap_d, LFS3_GBMAP_DSIZE));
if (err) {
// TODO switch to read-only?
return err;
}
// setup bmap with last known cursor, this will be populated on
// first alloc
LFS3_ASSERT(lfs3->gbmap.known == lfs3->block_count);
lfs3->bmap.gbatc = lfs3->gbmap.b;
lfs3->bmap.cursor = lfs3->gbmap.cursor;
lfs3->bmap.known = lfs3->gbmap.known;
lfs3->bmap.free = 0;
#endif
return 0;