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t: Adopted blocks={-1,-1} for clobbered/invalid mdirs

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blocks={0,0} technically worked, but only because the only mdirs allowed
at block 0 are mroot blocks. In theory, an mdir at block 0 could match
blocks={0,0} and clobber incorrectly, but it's not possible for such an
mdir to be in a non-trivial mtree, since blocks={0,1} are reserved for
the mrootanchor.

But bleh, that's complicated.

Setting blocks={-1,-1} makes the mdir truely invalid/unmatchable and
provides a stronger invariant at a minor code cost.

Code changes:

           code          stack
  before: 34554           2624
  after:  34566 (+0.0%)   2624 (+0.0%)
This commit is contained in:
Christopher Haster
2024-06-20 10:12:48 -05:00
parent cc90a77ff8
commit 7e96ff4dbd
1 changed files with 5 additions and 5 deletions
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lfs.c
+5 -5
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@@ -7834,7 +7834,7 @@ enum {
.o.state=LFSR_TSTATE_MROOTANCHOR, \
.o.flags=_flags, \
.o.mdir.mid=-1, \
.o.mdir.rbyd.blocks={0,0}, \
.o.mdir.rbyd.blocks={-1,-1}, \
.ot=NULL, \
.u.mtortoise.mptr={{0, 0}}, \
.u.mtortoise.step=0, \
@@ -7883,8 +7883,8 @@ static void lfsr_fs_traverserewind(lfs_t *lfs, lfsr_mtraversal_t *mt) {
mt->o.flags &= ~LFS_F_DIRTY;
mt->o.state = LFSR_TSTATE_MROOTANCHOR;
mt->o.mdir.mid = -1;
mt->o.mdir.rbyd.blocks[0] = 0;
mt->o.mdir.rbyd.blocks[1] = 0;
mt->o.mdir.rbyd.blocks[0] = -1;
mt->o.mdir.rbyd.blocks[1] = -1;
mt->ot = NULL;
mt->u.mtortoise.mptr.blocks[0] = 0;
mt->u.mtortoise.mptr.blocks[1] = 0;
@@ -7899,8 +7899,8 @@ static void lfsr_fs_traverseclobber(lfs_t *lfs, lfsr_mtraversal_t *mt,
// increment the mid (to make progress) and reset to mdir iteration
mt->o.state = LFSR_TSTATE_MDIRS;
mt->o.mdir.mid = mid;
mt->o.mdir.rbyd.blocks[0] = 0;
mt->o.mdir.rbyd.blocks[1] = 0;
mt->o.mdir.rbyd.blocks[0] = -1;
mt->o.mdir.rbyd.blocks[1] = -1;
mt->ot = NULL;
} else {
// move to next omdir