Github/littlefs
1
Fork 0
Code Actions Activity

Fixed mroot death returning LFS_ERR_CORRUPT -> LFS_ERR_NOSPC

Browse Source 
It's counter-intuitive, but no top-level API should return
LFS_ERR_CORRUPT. Instead, if we can't make progress because of a corrupt
block, we should return LFS_ERR_NOSPC. This makes it easier for users to
write code that is well behaved even when a device is end-of-life.

It's up to our mroot extension algorithm to make sure this case can't be
reached in normal operation unless the device is _actually_ at
end-of-life.

Because mroot extension is a bit of a special case, we weren't
converting these corrupt errors to nospc errors consistently. This is
fixed now, along with a couple more hopefully-useful logging statements.

Found while playing around with test_exhaustion + block_recycles=-1.
This should assert on bad wear-leveling, but LFS_ERR_CORRUPT was
unexpected. Added an explicit test because this is an easy thing to let
split through:

- test_badblocks_mrootanchor_wear

Code changes were surprisingly minimal, I wonder if constants are being
swapped out somewhere low-level?

           code          stack
  before: 33766           2600
  after:  33770 (+0.0%)   2600 (+0.0%)
This commit is contained in:
Christopher Haster
2024-06-05 00:02:32 -05:00
parent 26f3034813
commit 76ffb0e7b6
2 changed files with 67 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lfs.c
+19 -2
View File
@@ -6668,9 +6668,12 @@ relocate:;
err = lfsr_mdir_swap__(lfs, &mdir_, mdir, true);
if (err) {
// bad prog? try another block
// bad prog? can't do much here, mdir stuck
if (err == LFS_ERR_CORRUPT) {
goto relocate;
LFS_DEBUG("Stuck mdir 0x{%"PRIx32",%"PRIx32"}",
mdir->rbyd.blocks[0],
mdir->rbyd.blocks[1]);
return LFS_ERR_NOSPC;
}
return err;
}
@@ -7211,6 +7214,13 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
lfsr_mdir_t mrootanchor_;
err = lfsr_mdir_swap__(lfs, &mrootanchor_, &mrootchild, true);
if (err) {
// bad prog? can't do much here, mroot stuck
if (err == LFS_ERR_CORRUPT) {
LFS_DEBUG("Stuck mroot 0x{%"PRIx32",%"PRIx32"}",
mrootanchor_.rbyd.blocks[0],
mrootanchor_.rbyd.blocks[1]);
return LFS_ERR_NOSPC;
}
goto failed;
}
@@ -7228,6 +7238,13 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
LFS_ASSERT(err != LFS_ERR_NOENT);
// bad prog? can't do much here, mroot stuck
if (err == LFS_ERR_CORRUPT) {
LFS_DEBUG("Stuck mroot 0x{%"PRIx32",%"PRIx32"}",
mrootanchor_.rbyd.blocks[0],
mrootanchor_.rbyd.blocks[1]);
return LFS_ERR_NOSPC;
}
goto failed;
}
}