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Fixed allocation bugs near the end of storage

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Also added better testing specifically for these corner cases
around the end of storage
This commit is contained in:
Christopher Haster
2017-04-29 12:41:53 -05:00
parent 210b487325
commit a30142e0e1
3 changed files with 110 additions and 27 deletions
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lfs.c
+45 -27
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@@ -256,12 +256,12 @@ static inline bool lfs_pairisnull(const lfs_block_t pair[2]) {
static inline int lfs_paircmp(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return !((paira[0] == pairb[0] && paira[1] == pairb[1]) ||
(paira[0] == pairb[1] && paira[1] == pairb[0]));
return !(paira[0] == pairb[0] || paira[1] == pairb[1] ||
paira[0] == pairb[1] || paira[1] == pairb[0]);
}
static int lfs_dir_alloc(lfs_t *lfs, lfs_dir_t *dir) {
// Allocate pair of dir blocks
// allocate pair of dir blocks
for (int i = 0; i < 2; i++) {
int err = lfs_alloc(lfs, &dir->pair[i]);
if (err) {
@@ -269,21 +269,26 @@ static int lfs_dir_alloc(lfs_t *lfs, lfs_dir_t *dir) {
}
}
// Rather than clobbering one of the blocks we just pretend
// we couldn't find unique blocks, we're out of space
if (dir->pair[0] == dir->pair[1]) {
return LFS_ERR_NOSPC;
}
// rather than clobbering one of the blocks we just pretend
// the revision may be valid
int err = lfs_bd_read(lfs, dir->pair[0], 0, &dir->d.rev, 4);
if (err) {
return err;
}
// Set defaults
// set defaults
dir->d.rev += 1;
dir->d.size = sizeof(dir->d);
dir->d.tail[0] = 0;
dir->d.tail[1] = 0;
dir->off = sizeof(dir->d);
// Don't write out yet, let caller take care of that
// don't write out yet, let caller take care of that
return 0;
}
@@ -484,6 +489,7 @@ static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
return lfs_dir_commit(lfs, dir, entry, data);
}
// we need to allocate a new dir block
if (!(0x80000000 & dir->d.size)) {
lfs_dir_t newdir;
int err = lfs_dir_alloc(lfs, &newdir);
@@ -491,6 +497,13 @@ static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
return err;
}
// our allocator doesn't track blocks before being appended,
// so even if we found some blocks, they may not be unique
if (entry->d.type == LFS_TYPE_DIR &&
lfs_paircmp(entry->d.u.dir, newdir.pair) == 0) {
return LFS_ERR_NOSPC;
}
newdir.d.tail[0] = dir->d.tail[0];
newdir.d.tail[1] = dir->d.tail[1];
entry->off = newdir.d.size;
@@ -1677,7 +1690,7 @@ static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2]) {
.d.tail[1] = lfs->root[1],
};
while (parent.d.tail[0]) {
while (true) {
lfs_entry_t entry;
int err = lfs_dir_fetch(lfs, &parent, parent.d.tail);
if (err) {
@@ -1699,9 +1712,11 @@ static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2]) {
return true;
}
}
}
return false;
if (lfs_pairisnull(parent.d.tail)) {
return false;
}
}
}
int lfs_deorphan(lfs_t *lfs) {
@@ -1715,31 +1730,34 @@ int lfs_deorphan(lfs_t *lfs) {
return err;
}
while (pdir.d.tail[0]) {
while (!lfs_pairisnull(pdir.d.tail)) {
int err = lfs_dir_fetch(lfs, &cdir, pdir.d.tail);
if (err) {
return err;
}
// check if we have a parent
int parent = lfs_parent(lfs, pdir.d.tail);
if (parent < 0) {
return parent;
}
if (!parent) {
// we are an orphan
LFS_DEBUG("Orphan %d %d", pdir.d.tail[0], pdir.d.tail[1]);
pdir.d.tail[0] = cdir.d.tail[0];
pdir.d.tail[1] = cdir.d.tail[1];
err = lfs_dir_commit(lfs, &pdir, NULL, NULL);
if (err) {
return err;
// only check head blocks
if (!(0x80000000 & pdir.d.size)) {
// check if we have a parent
int parent = lfs_parent(lfs, pdir.d.tail);
if (parent < 0) {
return parent;
}
break;
if (!parent) {
// we are an orphan
LFS_DEBUG("Orphan %d %d", pdir.d.tail[0], pdir.d.tail[1]);
pdir.d.tail[0] = cdir.d.tail[0];
pdir.d.tail[1] = cdir.d.tail[1];
err = lfs_dir_commit(lfs, &pdir, NULL, NULL);
if (err) {
return err;
}
break;
}
}
memcpy(&pdir, &cdir, sizeof(pdir));