Github/littlefs
1
Fork 0
Code Actions Activity

t: Changed mtinfo/btinfo to refer to mdirs/rbyds by pointer

Browse Source 
This solves the issue of multiple mdirs/rbyds in lfsr_mtree_gc, where
it's easy for traversal state to fall out of sync when mutating parts of
the filesystem.

Is it good design, with self-referential pointers making everything more
entangled? Not sure!

This saves a bit of stack, but adds a bit of code, which makes sense,
pointer chasing can be costly. But both of these changes are well below
the compiler noise floor:

           code          stack
  before: 35228           2688
  after:  35256 (+0.1%)   2680 (-0.3%)
This commit is contained in:
Christopher Haster
2024-07-04 02:10:40 -05:00
parent bfc108c1dc
commit 3c7b462659
5 changed files with 152 additions and 155 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lfs.c
+43 -46
View File
@@ -4992,8 +4992,8 @@ typedef struct lfsr_btinfo {
union {
// ignore the mdir here, things get a bit simpler if we can
// alias mtinfo=btinfo
lfsr_mdir_t mdir;
lfsr_rbyd_t rbyd;
const lfsr_mdir_t *mdir;
const lfsr_rbyd_t *rbyd;
lfsr_data_t data;
lfsr_bptr_t bptr;
} u;
@@ -5017,7 +5017,7 @@ static int lfsr_btree_traverse_(lfs_t *lfs, const lfsr_btree_t *btree,
*bid_ = btree->weight-1;
}
btinfo->tag = LFSR_TAG_BRANCH;
btinfo->u.rbyd = *bt->branch;
btinfo->u.rbyd = bt->branch;
return 0;
}
}
@@ -5070,7 +5070,7 @@ static int lfsr_btree_traverse_(lfs_t *lfs, const lfsr_btree_t *btree,
*bid_ = bt->bid + (rid__ - bt->rid);
}
btinfo->tag = LFSR_TAG_BRANCH;
btinfo->u.rbyd = *bt->branch;
btinfo->u.rbyd = bt->branch;
return 0;
}
@@ -8293,7 +8293,7 @@ static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_mtraversal_t *mt,
mt->o.o.state = LFSR_MTRAVERSAL_MROOTCHAIN;
mtinfo->tag = LFSR_TAG_MDIR;
mtinfo->u.mdir = mt->o.o.mdir;
mtinfo->u.mdir = &mt->o.o.mdir;
return 0;
// traverse the mroot chain, checking for mroot/mtree/mdir
@@ -8349,7 +8349,7 @@ static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_mtraversal_t *mt,
}
mtinfo->tag = LFSR_TAG_MDIR;
mtinfo->u.mdir = mt->o.o.mdir;
mtinfo->u.mdir = &mt->o.o.mdir;
return 0;
// found an mdir?
@@ -8370,7 +8370,7 @@ static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_mtraversal_t *mt,
mt->o.o.state = LFSR_MTRAVERSAL_MDIR;
mtinfo->tag = LFSR_TAG_MDIR;
mtinfo->u.mdir = mt->o.o.mdir;
mtinfo->u.mdir = &mt->o.o.mdir;
return 0;
// found an mtree?
@@ -8409,7 +8409,7 @@ static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_mtraversal_t *mt,
mt->o.o.state = LFSR_MTRAVERSAL_MDIR;
mtinfo->tag = LFSR_TAG_MDIR;
mtinfo->u.mdir = mt->o.o.mdir;
mtinfo->u.mdir = &mt->o.o.mdir;
return 0;
// scan for blocks/btrees in the current mdir
@@ -8569,9 +8569,9 @@ static int lfsr_mtree_traverse(lfs_t *lfs, lfsr_mtraversal_t *mt,
// we also need to fetch to know if we need to compact
|| lfsr_t_iscompact(mt->o.o.flags))
&& mtinfo->tag == LFSR_TAG_BRANCH) {
err = lfsr_rbyd_fetchck(lfs, &mtinfo->u.rbyd,
mtinfo->u.rbyd.blocks[0], mtinfo->u.rbyd.trunk,
mtinfo->u.rbyd.cksum);
err = lfsr_rbyd_fetchck(lfs, (lfsr_rbyd_t*)mtinfo->u.rbyd,
mtinfo->u.rbyd->blocks[0], mtinfo->u.rbyd->trunk,
mtinfo->u.rbyd->cksum);
if (err) {
return err;
}
@@ -8589,11 +8589,11 @@ static int lfsr_mtree_traverse(lfs_t *lfs, lfsr_mtraversal_t *mt,
// track in-use blocks
if (lfsr_t_islookahead(mt->o.o.flags)) {
if (mtinfo->tag == LFSR_TAG_MDIR) {
lfs_alloc_markinuse(lfs, mtinfo->u.mdir.rbyd.blocks[0]);
lfs_alloc_markinuse(lfs, mtinfo->u.mdir.rbyd.blocks[1]);
lfs_alloc_markinuse(lfs, mtinfo->u.mdir->rbyd.blocks[0]);
lfs_alloc_markinuse(lfs, mtinfo->u.mdir->rbyd.blocks[1]);
} else if (mtinfo->tag == LFSR_TAG_BRANCH) {
lfs_alloc_markinuse(lfs, mtinfo->u.rbyd.blocks[0]);
lfs_alloc_markinuse(lfs, mtinfo->u.rbyd->blocks[0]);
} else if (mtinfo->tag == LFSR_TAG_BLOCK) {
lfs_alloc_markinuse(lfs, mtinfo->u.bptr.data.u.disk.block);
@@ -8623,28 +8623,25 @@ static int lfsr_mtree_gc(lfs_t *lfs, lfsr_mtraversal_t *mt,
if (lfsr_t_iscompact(mt->o.o.flags)
&& mtinfo->tag == LFSR_TAG_MDIR
// exceed compaction threshold?
&& lfsr_rbyd_eoff(&mtinfo->u.mdir.rbyd)
&& lfsr_rbyd_eoff(&mtinfo->u.mdir->rbyd)
> ((lfs->cfg->gc_compact_thresh)
? lfs->cfg->gc_compact_thresh
: lfs->cfg->block_size - lfs->cfg->block_size/8)) {
LFS_DEBUG("Compacting mdir %"PRId32" "
"0x{%"PRIx32",%"PRIx32"} "
"(%"PRId32" > %"PRId32")",
mtinfo->u.mdir.mid >> lfs->mdir_bits,
mtinfo->u.mdir.rbyd.blocks[0],
mtinfo->u.mdir.rbyd.blocks[1],
lfsr_rbyd_eoff(&mtinfo->u.mdir.rbyd),
mtinfo->u.mdir->mid >> lfs->mdir_bits,
mtinfo->u.mdir->rbyd.blocks[0],
mtinfo->u.mdir->rbyd.blocks[1],
lfsr_rbyd_eoff(&mtinfo->u.mdir->rbyd),
(lfs->cfg->gc_compact_thresh)
? lfs->cfg->gc_compact_thresh
: lfs->cfg->block_size - lfs->cfg->block_size/8);
// TODO should we really have two mdir copies flying around?
LFS_ASSERT(lfsr_mdir_cmp(&mt->o.o.mdir, &mtinfo->u.mdir) == 0);
int err = lfsr_mdir_compact(lfs, &mt->o.o.mdir);
int err = lfsr_mdir_compact(lfs, (lfsr_mdir_t*)mtinfo->u.mdir);
if (err) {
return err;
}
mtinfo->u.mdir = mt->o.o.mdir;
// mark as dirty
mt->o.o.flags |= LFS_F_DIRTY;
@@ -8654,32 +8651,30 @@ static int lfsr_mtree_gc(lfs_t *lfs, lfsr_mtraversal_t *mt,
if (lfsr_t_iscompact(mt->o.o.flags)
&& mtinfo->tag == LFSR_TAG_BRANCH
// exceed compaction threshold?
&& lfsr_rbyd_eoff(&mtinfo->u.rbyd)
&& lfsr_rbyd_eoff(mtinfo->u.rbyd)
> ((lfs->cfg->gc_compact_thresh)
? lfs->cfg->gc_compact_thresh
: lfs->cfg->block_size - lfs->cfg->block_size/8)) {
LFS_DEBUG("Compacting rbyd 0x%"PRIx32".%"PRIx32" "
"(%"PRId32" > %"PRId32")",
mtinfo->u.rbyd.blocks[0],
lfsr_rbyd_trunk(&mtinfo->u.rbyd),
lfsr_rbyd_eoff(&mtinfo->u.rbyd),
mtinfo->u.rbyd->blocks[0],
lfsr_rbyd_trunk(mtinfo->u.rbyd),
lfsr_rbyd_eoff(mtinfo->u.rbyd),
(lfs->cfg->gc_compact_thresh)
? lfs->cfg->gc_compact_thresh
: lfs->cfg->block_size - lfs->cfg->block_size/8);
// TODO should we really have two btree copies flying around?
LFS_ASSERT(lfsr_rbyd_cmp(mt->u.bt.branch, &mtinfo->u.rbyd) == 0);
if (mt->o.o.state == LFSR_MTRAVERSAL_MTREE) {
int err = lfsr_btree_compact_(lfs, &mt->o.bshrub.u.btree,
// note we may be referencing the btree root here
mt->u.bt.bid, (lfsr_rbyd_t*)mt->u.bt.branch);
mt->u.bt.bid, (lfsr_rbyd_t*)mtinfo->u.rbyd);
if (err) {
return err;
}
} else {
int err = lfsr_bshrub_compact_(lfs, &mt->o.o.mdir, &mt->o.bshrub,
// note we may be referencing the btree root here
mt->u.bt.bid, (lfsr_rbyd_t*)mt->u.bt.branch);
mt->u.bt.bid, (lfsr_rbyd_t*)mtinfo->u.rbyd);
if (err) {
return err;
}
@@ -12268,11 +12263,11 @@ static int lfsr_mountinited(lfs_t *lfs) {
// found an mdir?
if (mtinfo.tag == LFSR_TAG_MDIR) {
// found an mroot?
if (mtinfo.u.mdir.mid == -1) {
if (mtinfo.u.mdir->mid == -1) {
// check for the magic string, all mroot should have this
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs,
&mtinfo.u.mdir, LFSR_TAG_MAGIC,
mtinfo.u.mdir, LFSR_TAG_MAGIC,
&data);
if (err) {
if (err == LFS_ERR_NOENT) {
@@ -12293,14 +12288,14 @@ static int lfsr_mountinited(lfs_t *lfs) {
}
// are we the last mroot?
err = lfsr_mdir_lookup(lfs, &mtinfo.u.mdir, LFSR_TAG_MROOT,
err = lfsr_mdir_lookup(lfs, mtinfo.u.mdir, LFSR_TAG_MROOT,
NULL);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
// track active mroot
lfs->mroot = mtinfo.u.mdir;
lfs->mroot = *mtinfo.u.mdir;
// mount/validate config in active mroot
err = lfsr_mountmroot(lfs, &lfs->mroot);
@@ -12313,25 +12308,27 @@ static int lfsr_mountinited(lfs_t *lfs) {
// found a direct mdir? keep track of this
if (lfsr_mtree_isnull(&lfs->mtree)) {
lfs->mtree = LFSR_MTREE_MPTR(
*lfsr_mdir_mptr(&mtinfo.u.mdir),
*lfsr_mdir_mptr(mtinfo.u.mdir),
(1 << lfs->mdir_bits));
}
}
// toss our cksum into the filesystem seed for pseudorandom
// numbers
lfs->seed ^= mtinfo.u.mdir.rbyd.cksum;
lfs->seed ^= mtinfo.u.mdir->rbyd.cksum;
// collect any gdeltas from this mdir
err = lfsr_fs_consumegdelta(lfs, &mtinfo.u.mdir);
err = lfsr_fs_consumegdelta(lfs, mtinfo.u.mdir);
if (err) {
return err;
}
// check for any orphaned files
for (lfs_size_t rid = 0; rid < mtinfo.u.mdir.rbyd.weight; rid++) {
for (lfs_size_t rid = 0;
rid < mtinfo.u.mdir->rbyd.weight;
rid++) {
lfsr_tag_t tag;
err = lfsr_rbyd_sublookup(lfs, &mtinfo.u.mdir.rbyd,
err = lfsr_rbyd_sublookup(lfs, &mtinfo.u.mdir->rbyd,
rid, LFSR_TAG_NAME,
&tag, NULL);
if (err) {
@@ -12345,7 +12342,7 @@ static int lfsr_mountinited(lfs_t *lfs) {
if (tag == LFSR_TAG_ORPHAN) {
LFS_DEBUG("Found orphaned file "
"%"PRId32".%"PRId32,
lfsr_mid_bid(lfs, mtinfo.u.mdir.mid)
lfsr_mid_bid(lfs, mtinfo.u.mdir->mid)
>> lfs->mdir_bits,
rid);
lfs->hasorphans = true;
@@ -12355,7 +12352,7 @@ static int lfsr_mountinited(lfs_t *lfs) {
// TODO switch to readonly?
LFS_ERROR("Found unknown file type "
"%"PRId32".%"PRId32" 0x%"PRIx16,
lfsr_mid_bid(lfs, mtinfo.u.mdir.mid)
lfsr_mid_bid(lfs, mtinfo.u.mdir->mid)
>> lfs->mdir_bits,
rid,
lfsr_tag_subtype(tag));
@@ -12367,7 +12364,7 @@ static int lfsr_mountinited(lfs_t *lfs) {
} else if (mtinfo.tag == LFSR_TAG_BRANCH) {
// found the root of the mtree? keep track of this
if (lfsr_mtree_isnull(&lfs->mtree)) {
lfs->mtree.u.btree = mtinfo.u.rbyd;
lfs->mtree.u.btree = *mtinfo.u.rbyd;
}
} else {
@@ -12867,12 +12864,12 @@ int lfsr_traversal_read(lfs_t *lfs, lfsr_traversal_t *t,
// figure out type/blocks
if (mtinfo.tag == LFSR_TAG_MDIR) {
t->o.o.flags = (t->o.o.flags & ~0x7) | LFS_BTYPE_MDIR;
t->blocks[0] = mtinfo.u.mdir.rbyd.blocks[0];
t->blocks[1] = mtinfo.u.mdir.rbyd.blocks[1];
t->blocks[0] = mtinfo.u.mdir->rbyd.blocks[0];
t->blocks[1] = mtinfo.u.mdir->rbyd.blocks[1];
} else if (mtinfo.tag == LFSR_TAG_BRANCH) {
t->o.o.flags = (t->o.o.flags & ~0x7) | LFS_BTYPE_BTREE;
t->blocks[0] = mtinfo.u.rbyd.blocks[0];
t->blocks[0] = mtinfo.u.rbyd->blocks[0];
t->blocks[1] = -1;
} else if (mtinfo.tag == LFSR_TAG_BLOCK) {