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Expanded fuzz testing a bit, found/fixed an mid neighbor update bug

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This bug was just overlooked in testing the mtree, fortunately dir
fuzzing found it. Though since this depends on neighboring mdirs, it
probably would have been found quicker with smaller block sizes. At the
moment I am only testing on NOR-liked geometry (4KiB blocks).

The fix is easy, we can use the difference in the mtree size to
determine if a split or drop happened in mdir commit, since at most one
of these can happen on any mdir commit.

Also added an explicit test for mid updates when splitting and dropping.
This commit is contained in:
Christopher Haster
2023-07-07 16:31:52 -05:00
parent 039bdf91b4
commit cb1319c9e6
4 changed files with 237 additions and 29 deletions
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lfs.c
+22 -9
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@@ -4966,14 +4966,14 @@ static inline int lfsr_mtree_isinlined(lfs_t *lfs) {
return lfsr_btree_weight(&lfs->mtree) == 0;
}
static inline lfs_ssize_t lfsr_mtree_weight(lfs_t *lfs) {
static inline lfs_size_t lfsr_mtree_weight(lfs_t *lfs) {
return lfsr_btree_weight(&lfs->mtree);
}
static int lfsr_mtree_lookup(lfs_t *lfs, lfs_ssize_t mid, lfsr_mdir_t *mdir_) {
// TODO should we really allow -1=>mroot lookup?
LFS_ASSERT(mid >= -1);
LFS_ASSERT(mid < lfsr_mtree_weight(lfs));
LFS_ASSERT(mid < (lfs_ssize_t)lfsr_mtree_weight(lfs));
// looking up mroot?
if (mid < 0) {
@@ -5649,17 +5649,18 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir, lfs_ssize_t *rid,
}
// success?? update in-device state
lfs->mroot = mroot_;
lfs->mtree = mtree_;
// update any opened mdirs
for (lfsr_openedmdir_t *opened = lfs->opened;
opened;
opened = opened->next) {
if (opened->mdir.mid == mdir->mid
// avoid double-updating our current mdir
&& &opened->mdir != mdir) {
LFS_ASSERT(opened->rid <= (lfs_ssize_t)opened->mdir.rbyd.weight);
// avoid double-updating our current mdir
if (&opened->mdir == mdir) {
continue;
}
if (opened->mdir.mid == mdir->mid) {
LFS_ASSERT(opened->rid < (lfs_ssize_t)opened->mdir.rbyd.weight);
LFS_ASSERT(opened->rid != -1);
// first play out any attrs that change our rid
@@ -5681,12 +5682,24 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir, lfs_ssize_t *rid,
} else if ((lfs_size_t)opened->rid < mdir_.rbyd.weight) {
opened->mdir = mdir_;
} else {
LFS_ASSERT(lfsr_btree_weight(&mtree_)
!= lfsr_mtree_weight(lfs));
opened->rid = opened->rid - mdir_.rbyd.weight;
opened->mdir = msibling_;
}
// update mid if we had a split or drop
} else if (opened->mdir.mid > mdir->mid
&& lfsr_btree_weight(&mtree_) != lfsr_mtree_weight(lfs)) {
opened->mdir.mid += lfsr_btree_weight(&mtree_)
- lfsr_mtree_weight(lfs);
}
}
// update our mroot and mtree
lfs->mroot = mroot_;
lfs->mtree = mtree_;
// update mdir to follow requested rid
lfs_ssize_t rid_ = *rid;
LFS_ASSERT(rid_ <= (lfs_ssize_t)mdir->rbyd.weight);
@@ -6904,7 +6917,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
if (rid >= (lfs_ssize_t)dir->mdir.mdir.rbyd.weight) {
// out of mdirs?
lfs_ssize_t mid = dir->mdir.mdir.mid + 1;
if (mid >= lfsr_mtree_weight(lfs)) {
if (mid >= (lfs_ssize_t)lfsr_mtree_weight(lfs)) {
return LFS_ERR_NOENT;
}