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Fixed test bugs around handling corruption

Browse Source 
The main thing to consider was how lfs_dir_fetchwith reacts to
corruption it finds and to make sure falling back to old values works
correctly.

Some of the tricky bits involved making sure we could fall back to both old
commits and old metadata blocks while still handling things like
synthetic moves correctly.
This commit is contained in:
Christopher Haster
2018-07-30 14:23:51 -05:00
parent 3e246da52c
commit 225706044e
2 changed files with 47 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

85
lfs.c
View File

@@ -488,8 +488,7 @@ static int32_t lfs_commitget(lfs_t *lfs, lfs_block_t block, lfs_off_t off,
uint32_t tag, uint32_t getmask, uint32_t gettag, int32_t getdiff,
void *buffer, bool stopatcommit) {
// iterate over dir block backwards (for faster lookups)
while (off > sizeof(tag)) {
LFS_ASSERT(off > sizeof(tag)+lfs_tagsize(tag));
while (off >= 2*sizeof(tag)+lfs_tagsize(tag)) {
off -= sizeof(tag)+lfs_tagsize(tag);
if (lfs_tagtype(tag) == LFS_TYPE_CRC && stopatcommit) {
@@ -1133,23 +1132,22 @@ static int32_t lfs_dir_find(lfs_t *lfs,
lfs_off_t off = sizeof(dir->rev);
uint32_t ptag = 0;
uint32_t crc = 0xffffffff;
dir->tail[0] = 0xffffffff;
dir->tail[1] = 0xffffffff;
dir->count = 0;
dir->split = false;
dir->locals = (lfs_globals_t){0};
dir->rev = lfs_tole32(rev[0]);
lfs_crc(&crc, &dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev);
dir->off = 0;
lfs_mdir_t tempdir = *dir;
uint32_t tempfoundtag = foundtag;
uint16_t tempcount = 0;
lfs_block_t temptail[2] = {0xffffffff, 0xffffffff};
bool tempsplit = false;
lfs_globals_t templocals = (lfs_globals_t){0};
while (true) {
// extract next tag
uint32_t tag;
int err = lfs_bd_read(lfs, tempdir.pair[0],
int err = lfs_bd_read(lfs, dir->pair[0],
off, &tag, sizeof(tag));
if (err) {
return err;
@@ -1161,67 +1159,66 @@ static int32_t lfs_dir_find(lfs_t *lfs,
// next commit not yet programmed
if (lfs_tagtype(ptag) == LFS_TYPE_CRC && !lfs_tagisvalid(tag)) {
dir->erased = true;
goto done;
break;
}
// check we're in valid range
if (off + sizeof(tag)+lfs_tagsize(tag) > lfs->cfg->block_size) {
dir->erased = false;
break;
}
if (lfs_tagtype(tag) == LFS_TYPE_CRC) {
// check the crc attr
uint32_t dcrc;
int err = lfs_bd_read(lfs, tempdir.pair[0],
int err = lfs_bd_read(lfs, dir->pair[0],
off+sizeof(tag), &dcrc, sizeof(dcrc));
if (err) {
return err;
}
if (crc != lfs_fromle32(dcrc)) {
if (off == sizeof(tempdir.rev)) {
// try other block
break;
} else {
// consider what we have good enough
dir->erased = false;
goto done;
}
break;
}
tempdir.off = off + sizeof(tag)+lfs_tagsize(tag);
tempdir.etag = tag;
crc = 0xffffffff;
*dir = tempdir;
foundtag = tempfoundtag;
dir->off = off + sizeof(tag)+lfs_tagsize(tag);
dir->etag = tag;
dir->count = tempcount;
dir->tail[0] = temptail[0];
dir->tail[1] = temptail[1];
dir->split = tempsplit;
dir->locals = templocals;
crc = 0xffffffff;
} else {
err = lfs_bd_crc(lfs, tempdir.pair[0],
err = lfs_bd_crc(lfs, dir->pair[0],
off+sizeof(tag), lfs_tagsize(tag), &crc);
if (err) {
return err;
}
if (lfs_tagid(tag) < 0x3ff &&
lfs_tagid(tag) >= tempdir.count) {
tempdir.count = lfs_tagid(tag)+1;
if (lfs_tagid(tag) < 0x3ff && lfs_tagid(tag) >= tempcount) {
tempcount = lfs_tagid(tag)+1;
}
// TODO use subtype accross all of these?
if (lfs_tagsubtype(tag) == LFS_TYPE_TAIL) {
tempdir.split = (lfs_tagtype(tag) & 1);
err = lfs_bd_read(lfs, tempdir.pair[0], off+sizeof(tag),
tempdir.tail, sizeof(tempdir.tail));
tempsplit = (lfs_tagtype(tag) & 1);
err = lfs_bd_read(lfs, dir->pair[0], off+sizeof(tag),
temptail, sizeof(temptail));
if (err) {
return err;
}
} else if (lfs_tagtype(tag) == LFS_TYPE_GLOBALS) {
err = lfs_bd_read(lfs, tempdir.pair[0], off+sizeof(tag),
&tempdir.locals, sizeof(tempdir.locals));
err = lfs_bd_read(lfs, dir->pair[0], off+sizeof(tag),
&templocals, sizeof(templocals));
if (err) {
return err;
}
} else if (lfs_tagtype(tag) == LFS_TYPE_DELETE) {
LFS_ASSERT(tempdir.count > 0);
tempdir.count -= 1;
LFS_ASSERT(tempcount > 0);
tempcount -= 1;
if (lfs_tagid(tag) == lfs_tagid(tempfoundtag)) {
tempfoundtag = LFS_ERR_NOENT;
@@ -1230,7 +1227,7 @@ static int32_t lfs_dir_find(lfs_t *lfs,
tempfoundtag -= LFS_MKTAG(0, 1, 0);
}
} else if ((tag & findmask) == (findtag & findmask)) {
int res = lfs_bd_cmp(lfs, tempdir.pair[0], off+sizeof(tag),
int res = lfs_bd_cmp(lfs, dir->pair[0], off+sizeof(tag),
findbuffer, lfs_tagsize(tag));
if (res < 0) {
return res;
@@ -1247,15 +1244,8 @@ static int32_t lfs_dir_find(lfs_t *lfs,
off += sizeof(tag)+lfs_tagsize(tag);
}
// failed, try the other crc?
lfs_pairswap(dir->pair);
lfs_pairswap(rev);
}
LFS_ERROR("Corrupted dir pair at %d %d", dir->pair[0], dir->pair[1]);
return LFS_ERR_CORRUPT;
done:
// consider what we have good enough
if (dir->off > 0) {
// synthetic move
if (lfs_paircmp(dir->pair, lfs->globals.move.pair) == 0) {
if (lfs->globals.move.id == lfs_tagid(foundtag)) {
@@ -1269,6 +1259,15 @@ done:
return foundtag;
}
// failed, try the other crc?
lfs_pairswap(dir->pair);
lfs_pairswap(rev);
}
LFS_ERROR("Corrupted dir pair at %d %d", dir->pair[0], dir->pair[1]);
return LFS_ERR_CORRUPT;
}
static int lfs_dir_fetch(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2]) {
int32_t res = lfs_dir_find(lfs, dir, pair, 0xffffffff, 0xffffffff, NULL);

3
tests/test_corrupt.sh
View File

@@ -78,11 +78,8 @@ do
rm -rf blocks
mkdir blocks
ln -s /dev/zero blocks/$(printf '%x' $i)
echo $i 1i
lfs_mktree
echo $i 2i
lfs_chktree
echo $i 3i
done
echo "--- Block persistance ---"