lib/littlefs: Update LittleFS to v2.10.2.

Going above the root directory (/../foo) now gives an error.  This is an
intentional change made by LittleFS.  It required a update of the testsuite
and is a (minor) compatibility break.

Signed-off-by: Daniël van de Giessen <daniel@dvdgiessen.nl>

5 files changed, 585 insertions, 339 deletions

diff --git a/lib/littlefs/lfs2.c b/lib/littlefs/lfs2.c
index d89c42fd59..f9ce2cf290 100644
--- a/lib/littlefs/lfs2.c
+++ b/lib/littlefs/lfs2.c
@@ -282,6 +282,21 @@ static int lfs2_bd_erase(lfs2_t *lfs2, lfs2_block_t block) {
 
 
 /// Small type-level utilities ///
+
+// some operations on paths
+static inline lfs2_size_t lfs2_path_namelen(const char *path) {
+    return strcspn(path, "/");
+}
+
+static inline bool lfs2_path_islast(const char *path) {
+    lfs2_size_t namelen = lfs2_path_namelen(path);
+    return path[namelen + strspn(path + namelen, "/")] == '\0';
+}
+
+static inline bool lfs2_path_isdir(const char *path) {
+    return path[lfs2_path_namelen(path)] != '\0';
+}
+
 // operations on block pairs
 static inline void lfs2_pair_swap(lfs2_block_t pair[2]) {
     lfs2_block_t t = pair[0];
@@ -389,18 +404,15 @@ struct lfs2_diskoff {
 
 // operations on global state
 static inline void lfs2_gstate_xor(lfs2_gstate_t *a, const lfs2_gstate_t *b) {
-    for (int i = 0; i < 3; i++) {
-        ((uint32_t*)a)[i] ^= ((const uint32_t*)b)[i];
-    }
+    a->tag ^= b->tag;
+    a->pair[0] ^= b->pair[0];
+    a->pair[1] ^= b->pair[1];
 }
 
 static inline bool lfs2_gstate_iszero(const lfs2_gstate_t *a) {
-    for (int i = 0; i < 3; i++) {
-        if (((uint32_t*)a)[i] != 0) {
-            return false;
-        }
-    }
-    return true;
+    return a->tag == 0
+            && a->pair[0] == 0
+            && a->pair[1] == 0;
 }
 
 #ifndef LFS2_READONLY
@@ -550,9 +562,9 @@ static int lfs2_dir_compact(lfs2_t *lfs2,
         lfs2_mdir_t *source, uint16_t begin, uint16_t end);
 static lfs2_ssize_t lfs2_file_flushedwrite(lfs2_t *lfs2, lfs2_file_t *file,
         const void *buffer, lfs2_size_t size);
-static lfs2_ssize_t lfs2_file_rawwrite(lfs2_t *lfs2, lfs2_file_t *file,
+static lfs2_ssize_t lfs2_file_write_(lfs2_t *lfs2, lfs2_file_t *file,
         const void *buffer, lfs2_size_t size);
-static int lfs2_file_rawsync(lfs2_t *lfs2, lfs2_file_t *file);
+static int lfs2_file_sync_(lfs2_t *lfs2, lfs2_file_t *file);
 static int lfs2_file_outline(lfs2_t *lfs2, lfs2_file_t *file);
 static int lfs2_file_flush(lfs2_t *lfs2, lfs2_file_t *file);
 
@@ -574,65 +586,72 @@ static int lfs21_traverse(lfs2_t *lfs2,
         int (*cb)(void*, lfs2_block_t), void *data);
 #endif
 
-static int lfs2_dir_rawrewind(lfs2_t *lfs2, lfs2_dir_t *dir);
+static int lfs2_dir_rewind_(lfs2_t *lfs2, lfs2_dir_t *dir);
 
 static lfs2_ssize_t lfs2_file_flushedread(lfs2_t *lfs2, lfs2_file_t *file,
         void *buffer, lfs2_size_t size);
-static lfs2_ssize_t lfs2_file_rawread(lfs2_t *lfs2, lfs2_file_t *file,
+static lfs2_ssize_t lfs2_file_read_(lfs2_t *lfs2, lfs2_file_t *file,
         void *buffer, lfs2_size_t size);
-static int lfs2_file_rawclose(lfs2_t *lfs2, lfs2_file_t *file);
-static lfs2_soff_t lfs2_file_rawsize(lfs2_t *lfs2, lfs2_file_t *file);
+static int lfs2_file_close_(lfs2_t *lfs2, lfs2_file_t *file);
+static lfs2_soff_t lfs2_file_size_(lfs2_t *lfs2, lfs2_file_t *file);
 
-static lfs2_ssize_t lfs2_fs_rawsize(lfs2_t *lfs2);
-static int lfs2_fs_rawtraverse(lfs2_t *lfs2,
+static lfs2_ssize_t lfs2_fs_size_(lfs2_t *lfs2);
+static int lfs2_fs_traverse_(lfs2_t *lfs2,
         int (*cb)(void *data, lfs2_block_t block), void *data,
         bool includeorphans);
 
 static int lfs2_deinit(lfs2_t *lfs2);
-static int lfs2_rawunmount(lfs2_t *lfs2);
+static int lfs2_unmount_(lfs2_t *lfs2);
 
 
 /// Block allocator ///
+
+// allocations should call this when all allocated blocks are committed to
+// the filesystem
+//
+// after a checkpoint, the block allocator may realloc any untracked blocks
+static void lfs2_alloc_ckpoint(lfs2_t *lfs2) {
+    lfs2->lookahead.ckpoint = lfs2->block_count;
+}
+
+// drop the lookahead buffer, this is done during mounting and failed
+// traversals in order to avoid invalid lookahead state
+static void lfs2_alloc_drop(lfs2_t *lfs2) {
+    lfs2->lookahead.size = 0;
+    lfs2->lookahead.next = 0;
+    lfs2_alloc_ckpoint(lfs2);
+}
+
 #ifndef LFS2_READONLY
 static int lfs2_alloc_lookahead(void *p, lfs2_block_t block) {
     lfs2_t *lfs2 = (lfs2_t*)p;
-    lfs2_block_t off = ((block - lfs2->free.off)
+    lfs2_block_t off = ((block - lfs2->lookahead.start)
             + lfs2->block_count) % lfs2->block_count;
 
-    if (off < lfs2->free.size) {
-        lfs2->free.buffer[off / 32] |= 1U << (off % 32);
+    if (off < lfs2->lookahead.size) {
+        lfs2->lookahead.buffer[off / 8] |= 1U << (off % 8);
     }
 
     return 0;
 }
 #endif
 
-// indicate allocated blocks have been committed into the filesystem, this
-// is to prevent blocks from being garbage collected in the middle of a
-// commit operation
-static void lfs2_alloc_ack(lfs2_t *lfs2) {
-    lfs2->free.ack = lfs2->block_count;
-}
-
-// drop the lookahead buffer, this is done during mounting and failed
-// traversals in order to avoid invalid lookahead state
-static void lfs2_alloc_drop(lfs2_t *lfs2) {
-    lfs2->free.size = 0;
-    lfs2->free.i = 0;
-    lfs2_alloc_ack(lfs2);
-}
-
 #ifndef LFS2_READONLY
-static int lfs2_fs_rawgc(lfs2_t *lfs2) {
-    // Move free offset at the first unused block (lfs2->free.i)
-    // lfs2->free.i is equal lfs2->free.size when all blocks are used
-    lfs2->free.off = (lfs2->free.off + lfs2->free.i) % lfs2->block_count;
-    lfs2->free.size = lfs2_min(8*lfs2->cfg->lookahead_size, lfs2->free.ack);
-    lfs2->free.i = 0;
+static int lfs2_alloc_scan(lfs2_t *lfs2) {
+    // move lookahead buffer to the first unused block
+    //
+    // note we limit the lookahead buffer to at most the amount of blocks
+    // checkpointed, this prevents the math in lfs2_alloc from underflowing
+    lfs2->lookahead.start = (lfs2->lookahead.start + lfs2->lookahead.next) 
+            % lfs2->block_count;
+    lfs2->lookahead.next = 0;
+    lfs2->lookahead.size = lfs2_min(
+            8*lfs2->cfg->lookahead_size,
+            lfs2->lookahead.ckpoint);
 
     // find mask of free blocks from tree
-    memset(lfs2->free.buffer, 0, lfs2->cfg->lookahead_size);
-    int err = lfs2_fs_rawtraverse(lfs2, lfs2_alloc_lookahead, lfs2, true);
+    memset(lfs2->lookahead.buffer, 0, lfs2->cfg->lookahead_size);
+    int err = lfs2_fs_traverse_(lfs2, lfs2_alloc_lookahead, lfs2, true);
     if (err) {
         lfs2_alloc_drop(lfs2);
         return err;
@@ -645,36 +664,49 @@ static int lfs2_fs_rawgc(lfs2_t *lfs2) {
 #ifndef LFS2_READONLY
 static int lfs2_alloc(lfs2_t *lfs2, lfs2_block_t *block) {
     while (true) {
-        while (lfs2->free.i != lfs2->free.size) {
-            lfs2_block_t off = lfs2->free.i;
-            lfs2->free.i += 1;
-            lfs2->free.ack -= 1;
-
-            if (!(lfs2->free.buffer[off / 32] & (1U << (off % 32)))) {
+        // scan our lookahead buffer for free blocks
+        while (lfs2->lookahead.next < lfs2->lookahead.size) {
+            if (!(lfs2->lookahead.buffer[lfs2->lookahead.next / 8]
+                    & (1U << (lfs2->lookahead.next % 8)))) {
                 // found a free block
-                *block = (lfs2->free.off + off) % lfs2->block_count;
-
-                // eagerly find next off so an alloc ack can
-                // discredit old lookahead blocks
-                while (lfs2->free.i != lfs2->free.size &&
-                        (lfs2->free.buffer[lfs2->free.i / 32]
-                            & (1U << (lfs2->free.i % 32)))) {
-                    lfs2->free.i += 1;
-                    lfs2->free.ack -= 1;
+                *block = (lfs2->lookahead.start + lfs2->lookahead.next)
+                        % lfs2->block_count;
+
+                // eagerly find next free block to maximize how many blocks
+                // lfs2_alloc_ckpoint makes available for scanning
+                while (true) {
+                    lfs2->lookahead.next += 1;
+                    lfs2->lookahead.ckpoint -= 1;
+
+                    if (lfs2->lookahead.next >= lfs2->lookahead.size
+                            || !(lfs2->lookahead.buffer[lfs2->lookahead.next / 8]
+                                & (1U << (lfs2->lookahead.next % 8)))) {
+                        return 0;
+                    }
                 }
-
-                return 0;
             }
+
+            lfs2->lookahead.next += 1;
+            lfs2->lookahead.ckpoint -= 1;
         }
 
-        // check if we have looked at all blocks since last ack
-        if (lfs2->free.ack == 0) {
-            LFS2_ERROR("No more free space %"PRIu32,
-                    lfs2->free.i + lfs2->free.off);
+        // In order to keep our block allocator from spinning forever when our
+        // filesystem is full, we mark points where there are no in-flight
+        // allocations with a checkpoint before starting a set of allocations.
+        //
+        // If we've looked at all blocks since the last checkpoint, we report
+        // the filesystem as out of storage.
+        //
+        if (lfs2->lookahead.ckpoint <= 0) {
+            LFS2_ERROR("No more free space 0x%"PRIx32,
+                    (lfs2->lookahead.start + lfs2->lookahead.next)
+                        % lfs2->block_count);
             return LFS2_ERR_NOSPC;
         }
 
-        int err = lfs2_fs_rawgc(lfs2);
+        // No blocks in our lookahead buffer, we need to scan the filesystem for
+        // unused blocks in the next lookahead window.
+        int err = lfs2_alloc_scan(lfs2);
         if(err) {
             return err;
         }
@@ -690,11 +722,14 @@ static lfs2_stag_t lfs2_dir_getslice(lfs2_t *lfs2, const lfs2_mdir_t *dir,
     lfs2_tag_t ntag = dir->etag;
     lfs2_stag_t gdiff = 0;
 
+    // synthetic moves
     if (lfs2_gstate_hasmovehere(&lfs2->gdisk, dir->pair) &&
-            lfs2_tag_id(gmask) != 0 &&
-            lfs2_tag_id(lfs2->gdisk.tag) <= lfs2_tag_id(gtag)) {
-        // synthetic moves
-        gdiff -= LFS2_MKTAG(0, 1, 0);
+            lfs2_tag_id(gmask) != 0) {
+        if (lfs2_tag_id(lfs2->gdisk.tag) == lfs2_tag_id(gtag)) {
+            return LFS2_ERR_NOENT;
+        } else if (lfs2_tag_id(lfs2->gdisk.tag) < lfs2_tag_id(gtag)) {
+            gdiff -= LFS2_MKTAG(0, 1, 0);
+        }
     }
 
     // iterate over dir block backwards (for faster lookups)
@@ -1438,32 +1473,46 @@ static int lfs2_dir_find_match(void *data,
     return LFS2_CMP_EQ;
 }
 
+// lfs2_dir_find tries to set path and id even if file is not found
+//
+// returns:
+// - 0                  if file is found
+// - LFS2_ERR_NOENT      if file or parent is not found
+// - LFS2_ERR_NOTDIR     if parent is not a dir
 static lfs2_stag_t lfs2_dir_find(lfs2_t *lfs2, lfs2_mdir_t *dir,
         const char **path, uint16_t *id) {
     // we reduce path to a single name if we can find it
     const char *name = *path;
-    if (id) {
-        *id = 0x3ff;
-    }
 
     // default to root dir
     lfs2_stag_t tag = LFS2_MKTAG(LFS2_TYPE_DIR, 0x3ff, 0);
     dir->tail[0] = lfs2->root[0];
     dir->tail[1] = lfs2->root[1];
 
+    // empty paths are not allowed
+    if (*name == '\0') {
+        return LFS2_ERR_INVAL;
+    }
+
     while (true) {
 nextname:
-        // skip slashes
-        name += strspn(name, "/");
+        // skip slashes if we're a directory
+        if (lfs2_tag_type3(tag) == LFS2_TYPE_DIR) {
+            name += strspn(name, "/");
+        }
         lfs2_size_t namelen = strcspn(name, "/");
 
-        // skip '.' and root '..'
-        if ((namelen == 1 && memcmp(name, ".", 1) == 0) ||
-            (namelen == 2 && memcmp(name, "..", 2) == 0)) {
+        // skip '.'
+        if (namelen == 1 && memcmp(name, ".", 1) == 0) {
             name += namelen;
             goto nextname;
         }
 
+        // error on unmatched '..', trying to go above root?
+        if (namelen == 2 && memcmp(name, "..", 2) == 0) {
+            return LFS2_ERR_INVAL;
+        }
+
         // skip if matched by '..' in name
         const char *suffix = name + namelen;
         lfs2_size_t sufflen;
@@ -1475,7 +1524,9 @@ nextname:
                 break;
             }
 
-            if (sufflen == 2 && memcmp(suffix, "..", 2) == 0) {
+            if (sufflen == 1 && memcmp(suffix, ".", 1) == 0) {
+                // noop
+            } else if (sufflen == 2 && memcmp(suffix, "..", 2) == 0) {
                 depth -= 1;
                 if (depth == 0) {
                     name = suffix + sufflen;
@@ -1489,14 +1540,14 @@ nextname:
         }
 
         // found path
-        if (name[0] == '\0') {
+        if (*name == '\0') {
             return tag;
         }
 
         // update what we've found so far
         *path = name;
 
-        // only continue if we hit a directory
+        // only continue if we're a directory
         if (lfs2_tag_type3(tag) != LFS2_TYPE_DIR) {
             return LFS2_ERR_NOTDIR;
         }
@@ -1516,8 +1567,7 @@ nextname:
             tag = lfs2_dir_fetchmatch(lfs2, dir, dir->tail,
                     LFS2_MKTAG(0x780, 0, 0),
                     LFS2_MKTAG(LFS2_TYPE_NAME, 0, namelen),
-                     // are we last name?
-                    (strchr(name, '/') == NULL) ? id : NULL,
+                    id,
                     lfs2_dir_find_match, &(struct lfs2_dir_find_match){
                         lfs2, name, namelen});
             if (tag < 0) {
@@ -2105,13 +2155,14 @@ static int lfs2_dir_splittingcompact(lfs2_t *lfs2, lfs2_mdir_t *dir,
             // And we cap at half a block to avoid degenerate cases with
             // nearly-full metadata blocks.
             //
+            lfs2_size_t metadata_max = (lfs2->cfg->metadata_max)
+                    ? lfs2->cfg->metadata_max
+                    : lfs2->cfg->block_size;
             if (end - split < 0xff
                     && size <= lfs2_min(
-                        lfs2->cfg->block_size - 40,
+                        metadata_max - 40,
                         lfs2_alignup(
-                            (lfs2->cfg->metadata_max
-                                ? lfs2->cfg->metadata_max
-                                : lfs2->cfg->block_size)/2,
+                            metadata_max/2,
                             lfs2->cfg->prog_size))) {
                 break;
             }
@@ -2146,14 +2197,16 @@ static int lfs2_dir_splittingcompact(lfs2_t *lfs2, lfs2_mdir_t *dir,
             && lfs2_pair_cmp(dir->pair, (const lfs2_block_t[2]){0, 1}) == 0) {
         // oh no! we're writing too much to the superblock,
         // should we expand?
-        lfs2_ssize_t size = lfs2_fs_rawsize(lfs2);
+        lfs2_ssize_t size = lfs2_fs_size_(lfs2);
         if (size < 0) {
             return size;
         }
 
-        // do we have extra space? littlefs can't reclaim this space
-        // by itself, so expand cautiously
-        if ((lfs2_size_t)size < lfs2->block_count/2) {
+        // littlefs cannot reclaim expanded superblocks, so expand cautiously
+        //
+        // if our filesystem is more than ~88% full, don't expand, this is
+        // somewhat arbitrary
+        if (lfs2->block_count - size > lfs2->block_count/8) {
             LFS2_DEBUG("Expanding superblock at rev %"PRIu32, dir->rev);
             int err = lfs2_dir_split(lfs2, dir, attrs, attrcount,
                     source, begin, end);
@@ -2166,7 +2219,8 @@ static int lfs2_dir_splittingcompact(lfs2_t *lfs2, lfs2_mdir_t *dir,
                 // we can do, we'll error later if we've become frozen
                 LFS2_WARN("Unable to expand superblock");
             } else {
-                end = begin;
+                // duplicate the superblock entry into the new superblock
+                end = 1;
             }
         }
     }
@@ -2312,7 +2366,8 @@ fixmlist:;
             if (d->m.pair != pair) {
                 for (int i = 0; i < attrcount; i++) {
                     if (lfs2_tag_type3(attrs[i].tag) == LFS2_TYPE_DELETE &&
-                            d->id == lfs2_tag_id(attrs[i].tag)) {
+                            d->id == lfs2_tag_id(attrs[i].tag) &&
+                            d->type != LFS2_TYPE_DIR) {
                         d->m.pair[0] = LFS2_BLOCK_NULL;
                         d->m.pair[1] = LFS2_BLOCK_NULL;
                     } else if (lfs2_tag_type3(attrs[i].tag) == LFS2_TYPE_DELETE &&
@@ -2333,7 +2388,9 @@ fixmlist:;
 
             while (d->id >= d->m.count && d->m.split) {
                 // we split and id is on tail now
-                d->id -= d->m.count;
+                if (lfs2_pair_cmp(d->m.tail, lfs2->root) != 0) {
+                    d->id -= d->m.count;
+                }
                 int err = lfs2_dir_fetch(lfs2, &d->m, d->m.tail);
                 if (err) {
                     return err;
@@ -2499,7 +2556,7 @@ static int lfs2_dir_orphaningcommit(lfs2_t *lfs2, lfs2_mdir_t *dir,
         if (err != LFS2_ERR_NOENT) {
             if (lfs2_gstate_hasorphans(&lfs2->gstate)) {
                 // next step, clean up orphans
-                err = lfs2_fs_preporphans(lfs2, -hasparent);
+                err = lfs2_fs_preporphans(lfs2, -(int8_t)hasparent);
                 if (err) {
                     return err;
                 }
@@ -2564,7 +2621,7 @@ static int lfs2_dir_commit(lfs2_t *lfs2, lfs2_mdir_t *dir,
 
 /// Top level directory operations ///
 #ifndef LFS2_READONLY
-static int lfs2_rawmkdir(lfs2_t *lfs2, const char *path) {
+static int lfs2_mkdir_(lfs2_t *lfs2, const char *path) {
     // deorphan if we haven't yet, needed at most once after poweron
     int err = lfs2_fs_forceconsistency(lfs2);
     if (err) {
@@ -2575,18 +2632,18 @@ static int lfs2_rawmkdir(lfs2_t *lfs2, const char *path) {
     cwd.next = lfs2->mlist;
     uint16_t id;
     err = lfs2_dir_find(lfs2, &cwd.m, &path, &id);
-    if (!(err == LFS2_ERR_NOENT && id != 0x3ff)) {
+    if (!(err == LFS2_ERR_NOENT && lfs2_path_islast(path))) {
         return (err < 0) ? err : LFS2_ERR_EXIST;
     }
 
     // check that name fits
-    lfs2_size_t nlen = strlen(path);
+    lfs2_size_t nlen = lfs2_path_namelen(path);
     if (nlen > lfs2->name_max) {
         return LFS2_ERR_NAMETOOLONG;
     }
 
     // build up new directory
-    lfs2_alloc_ack(lfs2);
+    lfs2_alloc_ckpoint(lfs2);
     lfs2_mdir_t dir;
     err = lfs2_dir_alloc(lfs2, &dir);
     if (err) {
@@ -2660,7 +2717,7 @@ static int lfs2_rawmkdir(lfs2_t *lfs2, const char *path) {
 }
 #endif
 
-static int lfs2_dir_rawopen(lfs2_t *lfs2, lfs2_dir_t *dir, const char *path) {
+static int lfs2_dir_open_(lfs2_t *lfs2, lfs2_dir_t *dir, const char *path) {
     lfs2_stag_t tag = lfs2_dir_find(lfs2, &dir->m, &path, NULL);
     if (tag < 0) {
         return tag;
@@ -2704,14 +2761,14 @@ static int lfs2_dir_rawopen(lfs2_t *lfs2, lfs2_dir_t *dir, const char *path) {
     return 0;
 }
 
-static int lfs2_dir_rawclose(lfs2_t *lfs2, lfs2_dir_t *dir) {
+static int lfs2_dir_close_(lfs2_t *lfs2, lfs2_dir_t *dir) {
     // remove from list of mdirs
     lfs2_mlist_remove(lfs2, (struct lfs2_mlist *)dir);
 
     return 0;
 }
 
-static int lfs2_dir_rawread(lfs2_t *lfs2, lfs2_dir_t *dir, struct lfs2_info *info) {
+static int lfs2_dir_read_(lfs2_t *lfs2, lfs2_dir_t *dir, struct lfs2_info *info) {
     memset(info, 0, sizeof(*info));
 
     // special offset for '.' and '..'
@@ -2756,9 +2813,9 @@ static int lfs2_dir_rawread(lfs2_t *lfs2, lfs2_dir_t *dir, struct lfs2_info *inf
     return true;
 }
 
-static int lfs2_dir_rawseek(lfs2_t *lfs2, lfs2_dir_t *dir, lfs2_off_t off) {
+static int lfs2_dir_seek_(lfs2_t *lfs2, lfs2_dir_t *dir, lfs2_off_t off) {
     // simply walk from head dir
-    int err = lfs2_dir_rawrewind(lfs2, dir);
+    int err = lfs2_dir_rewind_(lfs2, dir);
     if (err) {
         return err;
     }
@@ -2793,12 +2850,12 @@ static int lfs2_dir_rawseek(lfs2_t *lfs2, lfs2_dir_t *dir, lfs2_off_t off) {
     return 0;
 }
 
-static lfs2_soff_t lfs2_dir_rawtell(lfs2_t *lfs2, lfs2_dir_t *dir) {
+static lfs2_soff_t lfs2_dir_tell_(lfs2_t *lfs2, lfs2_dir_t *dir) {
     (void)lfs2;
     return dir->pos;
 }
 
-static int lfs2_dir_rawrewind(lfs2_t *lfs2, lfs2_dir_t *dir) {
+static int lfs2_dir_rewind_(lfs2_t *lfs2, lfs2_dir_t *dir) {
     // reload the head dir
     int err = lfs2_dir_fetch(lfs2, &dir->m, dir->head);
     if (err) {
@@ -3004,7 +3061,7 @@ static int lfs2_ctz_traverse(lfs2_t *lfs2,
 
 
 /// Top level file operations ///
-static int lfs2_file_rawopencfg(lfs2_t *lfs2, lfs2_file_t *file,
+static int lfs2_file_opencfg_(lfs2_t *lfs2, lfs2_file_t *file,
         const char *path, int flags,
         const struct lfs2_file_config *cfg) {
 #ifndef LFS2_READONLY
@@ -3029,7 +3086,7 @@ static int lfs2_file_rawopencfg(lfs2_t *lfs2, lfs2_file_t *file,
 
     // allocate entry for file if it doesn't exist
     lfs2_stag_t tag = lfs2_dir_find(lfs2, &file->m, &path, &file->id);
-    if (tag < 0 && !(tag == LFS2_ERR_NOENT && file->id != 0x3ff)) {
+    if (tag < 0 && !(tag == LFS2_ERR_NOENT && lfs2_path_islast(path))) {
         err = tag;
         goto cleanup;
     }
@@ -3049,8 +3106,14 @@ static int lfs2_file_rawopencfg(lfs2_t *lfs2, lfs2_file_t *file,
             goto cleanup;
         }
 
+        // don't allow trailing slashes
+        if (lfs2_path_isdir(path)) {
+            err = LFS2_ERR_NOTDIR;
+            goto cleanup;
+        }
+
         // check that name fits
-        lfs2_size_t nlen = strlen(path);
+        lfs2_size_t nlen = lfs2_path_namelen(path);
         if (nlen > lfs2->name_max) {
             err = LFS2_ERR_NAMETOOLONG;
             goto cleanup;
@@ -3166,22 +3229,22 @@ cleanup:
 #ifndef LFS2_READONLY
     file->flags |= LFS2_F_ERRED;
 #endif
-    lfs2_file_rawclose(lfs2, file);
+    lfs2_file_close_(lfs2, file);
     return err;
 }
 
 #ifndef LFS2_NO_MALLOC
-static int lfs2_file_rawopen(lfs2_t *lfs2, lfs2_file_t *file,
+static int lfs2_file_open_(lfs2_t *lfs2, lfs2_file_t *file,
         const char *path, int flags) {
     static const struct lfs2_file_config defaults = {0};
-    int err = lfs2_file_rawopencfg(lfs2, file, path, flags, &defaults);
+    int err = lfs2_file_opencfg_(lfs2, file, path, flags, &defaults);
     return err;
 }
 #endif
 
-static int lfs2_file_rawclose(lfs2_t *lfs2, lfs2_file_t *file) {
+static int lfs2_file_close_(lfs2_t *lfs2, lfs2_file_t *file) {
 #ifndef LFS2_READONLY
-    int err = lfs2_file_rawsync(lfs2, file);
+    int err = lfs2_file_sync_(lfs2, file);
 #else
     int err = 0;
 #endif
@@ -3272,7 +3335,7 @@ relocate:
 #ifndef LFS2_READONLY
 static int lfs2_file_outline(lfs2_t *lfs2, lfs2_file_t *file) {
     file->off = file->pos;
-    lfs2_alloc_ack(lfs2);
+    lfs2_alloc_ckpoint(lfs2);
     int err = lfs2_file_relocate(lfs2, file);
     if (err) {
         return err;
@@ -3364,7 +3427,7 @@ relocate:
 }
 
 #ifndef LFS2_READONLY
-static int lfs2_file_rawsync(lfs2_t *lfs2, lfs2_file_t *file) {
+static int lfs2_file_sync_(lfs2_t *lfs2, lfs2_file_t *file) {
     if (file->flags & LFS2_F_ERRED) {
         // it's not safe to do anything if our file errored
         return 0;
@@ -3379,6 +3442,15 @@ static int lfs2_file_rawsync(lfs2_t *lfs2, lfs2_file_t *file) {
 
     if ((file->flags & LFS2_F_DIRTY) &&
             !lfs2_pair_isnull(file->m.pair)) {
+        // before we commit metadata, we need sync the disk to make sure
+        // data writes don't complete after metadata writes
+        if (!(file->flags & LFS2_F_INLINE)) {
+            err = lfs2_bd_sync(lfs2, &lfs2->pcache, &lfs2->rcache, false);
+            if (err) {
+                return err;
+            }
+        }
+
         // update dir entry
         uint16_t type;
         const void *buffer;
@@ -3477,7 +3549,7 @@ static lfs2_ssize_t lfs2_file_flushedread(lfs2_t *lfs2, lfs2_file_t *file,
     return size;
 }
 
-static lfs2_ssize_t lfs2_file_rawread(lfs2_t *lfs2, lfs2_file_t *file,
+static lfs2_ssize_t lfs2_file_read_(lfs2_t *lfs2, lfs2_file_t *file,
         void *buffer, lfs2_size_t size) {
     LFS2_ASSERT((file->flags & LFS2_O_RDONLY) == LFS2_O_RDONLY);
 
@@ -3502,11 +3574,7 @@ static lfs2_ssize_t lfs2_file_flushedwrite(lfs2_t *lfs2, lfs2_file_t *file,
     lfs2_size_t nsize = size;
 
     if ((file->flags & LFS2_F_INLINE) &&
-            lfs2_max(file->pos+nsize, file->ctz.size) >
-            lfs2_min(0x3fe, lfs2_min(
-                lfs2->cfg->cache_size,
-                (lfs2->cfg->metadata_max ?
-                    lfs2->cfg->metadata_max : lfs2->cfg->block_size) / 8))) {
+            lfs2_max(file->pos+nsize, file->ctz.size) > lfs2->inline_max) {
         // inline file doesn't fit anymore
         int err = lfs2_file_outline(lfs2, file);
         if (err) {
@@ -3535,7 +3603,7 @@ static lfs2_ssize_t lfs2_file_flushedwrite(lfs2_t *lfs2, lfs2_file_t *file,
                 }
 
                 // extend file with new blocks
-                lfs2_alloc_ack(lfs2);
+                lfs2_alloc_ckpoint(lfs2);
                 int err = lfs2_ctz_extend(lfs2, &file->cache, &lfs2->rcache,
                         file->block, file->pos,
                         &file->block, &file->off);
@@ -3578,13 +3646,13 @@ relocate:
         data += diff;
         nsize -= diff;
 
-        lfs2_alloc_ack(lfs2);
+        lfs2_alloc_ckpoint(lfs2);
     }
 
     return size;
 }
 
-static lfs2_ssize_t lfs2_file_rawwrite(lfs2_t *lfs2, lfs2_file_t *file,
+static lfs2_ssize_t lfs2_file_write_(lfs2_t *lfs2, lfs2_file_t *file,
         const void *buffer, lfs2_size_t size) {
     LFS2_ASSERT((file->flags & LFS2_O_WRONLY) == LFS2_O_WRONLY);
 
@@ -3628,25 +3696,19 @@ static lfs2_ssize_t lfs2_file_rawwrite(lfs2_t *lfs2, lfs2_file_t *file,
 }
 #endif
 
-static lfs2_soff_t lfs2_file_rawseek(lfs2_t *lfs2, lfs2_file_t *file,
+static lfs2_soff_t lfs2_file_seek_(lfs2_t *lfs2, lfs2_file_t *file,
         lfs2_soff_t off, int whence) {
     // find new pos
+    //
+    // fortunately for us, littlefs is limited to 31-bit file sizes, so we
+    // don't have to worry too much about integer overflow
     lfs2_off_t npos = file->pos;
     if (whence == LFS2_SEEK_SET) {
         npos = off;
     } else if (whence == LFS2_SEEK_CUR) {
-        if ((lfs2_soff_t)file->pos + off < 0) {
-            return LFS2_ERR_INVAL;
-        } else {
-            npos = file->pos + off;
-        }
+        npos = file->pos + (lfs2_off_t)off;
     } else if (whence == LFS2_SEEK_END) {
-        lfs2_soff_t res = lfs2_file_rawsize(lfs2, file) + off;
-        if (res < 0) {
-            return LFS2_ERR_INVAL;
-        } else {
-            npos = res;
-        }
+        npos = (lfs2_off_t)lfs2_file_size_(lfs2, file) + (lfs2_off_t)off;
     }
 
     if (npos > lfs2->file_max) {
@@ -3661,13 +3723,8 @@ static lfs2_soff_t lfs2_file_rawseek(lfs2_t *lfs2, lfs2_file_t *file,
 
     // if we're only reading and our new offset is still in the file's cache
     // we can avoid flushing and needing to reread the data
-    if (
-#ifndef LFS2_READONLY
-        !(file->flags & LFS2_F_WRITING)
-#else
-        true
-#endif
-            ) {
+    if ((file->flags & LFS2_F_READING)
+            && file->off != lfs2->cfg->block_size) {
         int oindex = lfs2_ctz_index(lfs2, &(lfs2_off_t){file->pos});
         lfs2_off_t noff = npos;
         int nindex = lfs2_ctz_index(lfs2, &noff);
@@ -3692,7 +3749,7 @@ static lfs2_soff_t lfs2_file_rawseek(lfs2_t *lfs2, lfs2_file_t *file,
 }
 
 #ifndef LFS2_READONLY
-static int lfs2_file_rawtruncate(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t size) {
+static int lfs2_file_truncate_(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t size) {
     LFS2_ASSERT((file->flags & LFS2_O_WRONLY) == LFS2_O_WRONLY);
 
     if (size > LFS2_FILE_MAX) {
@@ -3700,15 +3757,12 @@ static int lfs2_file_rawtruncate(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t siz
     }
 
     lfs2_off_t pos = file->pos;
-    lfs2_off_t oldsize = lfs2_file_rawsize(lfs2, file);
+    lfs2_off_t oldsize = lfs2_file_size_(lfs2, file);
     if (size < oldsize) {
         // revert to inline file?
-        if (size <= lfs2_min(0x3fe, lfs2_min(
-                lfs2->cfg->cache_size,
-                (lfs2->cfg->metadata_max ?
-                    lfs2->cfg->metadata_max : lfs2->cfg->block_size) / 8))) {
+        if (size <= lfs2->inline_max) {
             // flush+seek to head
-            lfs2_soff_t res = lfs2_file_rawseek(lfs2, file, 0, LFS2_SEEK_SET);
+            lfs2_soff_t res = lfs2_file_seek_(lfs2, file, 0, LFS2_SEEK_SET);
             if (res < 0) {
                 return (int)res;
             }
@@ -3753,14 +3807,14 @@ static int lfs2_file_rawtruncate(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t siz
         }
     } else if (size > oldsize) {
         // flush+seek if not already at end
-        lfs2_soff_t res = lfs2_file_rawseek(lfs2, file, 0, LFS2_SEEK_END);
+        lfs2_soff_t res = lfs2_file_seek_(lfs2, file, 0, LFS2_SEEK_END);
         if (res < 0) {
             return (int)res;
         }
 
         // fill with zeros
         while (file->pos < size) {
-            res = lfs2_file_rawwrite(lfs2, file, &(uint8_t){0}, 1);
+            res = lfs2_file_write_(lfs2, file, &(uint8_t){0}, 1);
             if (res < 0) {
                 return (int)res;
             }
@@ -3768,7 +3822,7 @@ static int lfs2_file_rawtruncate(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t siz
     }
 
     // restore pos
-    lfs2_soff_t res = lfs2_file_rawseek(lfs2, file, pos, LFS2_SEEK_SET);
+    lfs2_soff_t res = lfs2_file_seek_(lfs2, file, pos, LFS2_SEEK_SET);
     if (res < 0) {
       return (int)res;
     }
@@ -3777,13 +3831,13 @@ static int lfs2_file_rawtruncate(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t siz
 }
 #endif
 
-static lfs2_soff_t lfs2_file_rawtell(lfs2_t *lfs2, lfs2_file_t *file) {
+static lfs2_soff_t lfs2_file_tell_(lfs2_t *lfs2, lfs2_file_t *file) {
     (void)lfs2;
     return file->pos;
 }
 
-static int lfs2_file_rawrewind(lfs2_t *lfs2, lfs2_file_t *file) {
-    lfs2_soff_t res = lfs2_file_rawseek(lfs2, file, 0, LFS2_SEEK_SET);
+static int lfs2_file_rewind_(lfs2_t *lfs2, lfs2_file_t *file) {
+    lfs2_soff_t res = lfs2_file_seek_(lfs2, file, 0, LFS2_SEEK_SET);
     if (res < 0) {
         return (int)res;
     }
@@ -3791,7 +3845,7 @@ static int lfs2_file_rawrewind(lfs2_t *lfs2, lfs2_file_t *file) {
     return 0;
 }
 
-static lfs2_soff_t lfs2_file_rawsize(lfs2_t *lfs2, lfs2_file_t *file) {
+static lfs2_soff_t lfs2_file_size_(lfs2_t *lfs2, lfs2_file_t *file) {
     (void)lfs2;
 
 #ifndef LFS2_READONLY
@@ -3805,18 +3859,24 @@ static lfs2_soff_t lfs2_file_rawsize(lfs2_t *lfs2, lfs2_file_t *file) {
 
 
 /// General fs operations ///
-static int lfs2_rawstat(lfs2_t *lfs2, const char *path, struct lfs2_info *info) {
+static int lfs2_stat_(lfs2_t *lfs2, const char *path, struct lfs2_info *info) {
     lfs2_mdir_t cwd;
     lfs2_stag_t tag = lfs2_dir_find(lfs2, &cwd, &path, NULL);
     if (tag < 0) {
         return (int)tag;
     }
 
+    // only allow trailing slashes on dirs
+    if (strchr(path, '/') != NULL
+            && lfs2_tag_type3(tag) != LFS2_TYPE_DIR) {
+        return LFS2_ERR_NOTDIR;
+    }
+
     return lfs2_dir_getinfo(lfs2, &cwd, lfs2_tag_id(tag), info);
 }
 
 #ifndef LFS2_READONLY
-static int lfs2_rawremove(lfs2_t *lfs2, const char *path) {
+static int lfs2_remove_(lfs2_t *lfs2, const char *path) {
     // deorphan if we haven't yet, needed at most once after poweron
     int err = lfs2_fs_forceconsistency(lfs2);
     if (err) {
@@ -3895,7 +3955,7 @@ static int lfs2_rawremove(lfs2_t *lfs2, const char *path) {
 #endif
 
 #ifndef LFS2_READONLY
-static int lfs2_rawrename(lfs2_t *lfs2, const char *oldpath, const char *newpath) {
+static int lfs2_rename_(lfs2_t *lfs2, const char *oldpath, const char *newpath) {
     // deorphan if we haven't yet, needed at most once after poweron
     int err = lfs2_fs_forceconsistency(lfs2);
     if (err) {
@@ -3914,7 +3974,7 @@ static int lfs2_rawrename(lfs2_t *lfs2, const char *oldpath, const char *newpath
     uint16_t newid;
     lfs2_stag_t prevtag = lfs2_dir_find(lfs2, &newcwd, &newpath, &newid);
     if ((prevtag < 0 || lfs2_tag_id(prevtag) == 0x3ff) &&
-            !(prevtag == LFS2_ERR_NOENT && newid != 0x3ff)) {
+            !(prevtag == LFS2_ERR_NOENT && lfs2_path_islast(newpath))) {
         return (prevtag < 0) ? (int)prevtag : LFS2_ERR_INVAL;
     }
 
@@ -3925,8 +3985,14 @@ static int lfs2_rawrename(lfs2_t *lfs2, const char *oldpath, const char *newpath
     struct lfs2_mlist prevdir;
     prevdir.next = lfs2->mlist;
     if (prevtag == LFS2_ERR_NOENT) {
+        // if we're a file, don't allow trailing slashes
+        if (lfs2_path_isdir(newpath)
+                && lfs2_tag_type3(oldtag) != LFS2_TYPE_DIR) {
+            return LFS2_ERR_NOTDIR;
+        }
+
         // check that name fits
-        lfs2_size_t nlen = strlen(newpath);
+        lfs2_size_t nlen = lfs2_path_namelen(newpath);
         if (nlen > lfs2->name_max) {
             return LFS2_ERR_NAMETOOLONG;
         }
@@ -3938,7 +4004,9 @@ static int lfs2_rawrename(lfs2_t *lfs2, const char *oldpath, const char *newpath
             newoldid += 1;
         }
     } else if (lfs2_tag_type3(prevtag) != lfs2_tag_type3(oldtag)) {
-        return LFS2_ERR_ISDIR;
+        return (lfs2_tag_type3(prevtag) == LFS2_TYPE_DIR)
+                ? LFS2_ERR_ISDIR
+                : LFS2_ERR_NOTDIR;
     } else if (samepair && newid == newoldid) {
         // we're renaming to ourselves??
         return 0;
@@ -3984,7 +4052,8 @@ static int lfs2_rawrename(lfs2_t *lfs2, const char *oldpath, const char *newpath
             {LFS2_MKTAG_IF(prevtag != LFS2_ERR_NOENT,
                 LFS2_TYPE_DELETE, newid, 0), NULL},
             {LFS2_MKTAG(LFS2_TYPE_CREATE, newid, 0), NULL},
-            {LFS2_MKTAG(lfs2_tag_type3(oldtag), newid, strlen(newpath)), newpath},
+            {LFS2_MKTAG(lfs2_tag_type3(oldtag),
+                newid, lfs2_path_namelen(newpath)), newpath},
             {LFS2_MKTAG(LFS2_FROM_MOVE, newid, lfs2_tag_id(oldtag)), &oldcwd},
             {LFS2_MKTAG_IF(samepair,
                 LFS2_TYPE_DELETE, newoldid, 0), NULL}));
@@ -4030,7 +4099,7 @@ static int lfs2_rawrename(lfs2_t *lfs2, const char *oldpath, const char *newpath
 }
 #endif
 
-static lfs2_ssize_t lfs2_rawgetattr(lfs2_t *lfs2, const char *path,
+static lfs2_ssize_t lfs2_getattr_(lfs2_t *lfs2, const char *path,
         uint8_t type, void *buffer, lfs2_size_t size) {
     lfs2_mdir_t cwd;
     lfs2_stag_t tag = lfs2_dir_find(lfs2, &cwd, &path, NULL);
@@ -4088,7 +4157,7 @@ static int lfs2_commitattr(lfs2_t *lfs2, const char *path,
 #endif
 
 #ifndef LFS2_READONLY
-static int lfs2_rawsetattr(lfs2_t *lfs2, const char *path,
+static int lfs2_setattr_(lfs2_t *lfs2, const char *path,
         uint8_t type, const void *buffer, lfs2_size_t size) {
     if (size > lfs2->attr_max) {
         return LFS2_ERR_NOSPC;
@@ -4099,13 +4168,28 @@ static int lfs2_rawsetattr(lfs2_t *lfs2, const char *path,
 #endif
 
 #ifndef LFS2_READONLY
-static int lfs2_rawremoveattr(lfs2_t *lfs2, const char *path, uint8_t type) {
+static int lfs2_removeattr_(lfs2_t *lfs2, const char *path, uint8_t type) {
     return lfs2_commitattr(lfs2, path, type, NULL, 0x3ff);
 }
 #endif
 
 
 /// Filesystem operations ///
+
+// compile time checks, see lfs2.h for why these limits exist
+#if LFS2_NAME_MAX > 1022
+#error "Invalid LFS2_NAME_MAX, must be <= 1022"
+#endif
+
+#if LFS2_FILE_MAX > 2147483647
+#error "Invalid LFS2_FILE_MAX, must be <= 2147483647"
+#endif
+
+#if LFS2_ATTR_MAX > 1022
+#error "Invalid LFS2_ATTR_MAX, must be <= 1022"
+#endif
+
+// common filesystem initialization
 static int lfs2_init(lfs2_t *lfs2, const struct lfs2_config *cfg) {
     lfs2->cfg = cfg;
     lfs2->block_count = cfg->block_count;  // May be 0
@@ -4126,6 +4210,14 @@ static int lfs2_init(lfs2_t *lfs2, const struct lfs2_config *cfg) {
     // which littlefs currently does not support
     LFS2_ASSERT((bool)0x80000000);
 
+    // check that the required io functions are provided
+    LFS2_ASSERT(lfs2->cfg->read != NULL);
+#ifndef LFS2_READONLY
+    LFS2_ASSERT(lfs2->cfg->prog != NULL);
+    LFS2_ASSERT(lfs2->cfg->erase != NULL);
+    LFS2_ASSERT(lfs2->cfg->sync != NULL);
+#endif
+
     // validate that the lfs2-cfg sizes were initiated properly before
     // performing any arithmetic logics with them
     LFS2_ASSERT(lfs2->cfg->read_size != 0);
@@ -4153,6 +4245,23 @@ static int lfs2_init(lfs2_t *lfs2, const struct lfs2_config *cfg) {
     // wear-leveling.
     LFS2_ASSERT(lfs2->cfg->block_cycles != 0);
 
+    // check that compact_thresh makes sense
+    //
+    // metadata can't be compacted below block_size/2, and metadata can't
+    // exceed a block_size
+    LFS2_ASSERT(lfs2->cfg->compact_thresh == 0
+            || lfs2->cfg->compact_thresh >= lfs2->cfg->block_size/2);
+    LFS2_ASSERT(lfs2->cfg->compact_thresh == (lfs2_size_t)-1
+            || lfs2->cfg->compact_thresh <= lfs2->cfg->block_size);
+
+    // check that metadata_max is a multiple of read_size and prog_size,
+    // and a factor of the block_size
+    LFS2_ASSERT(!lfs2->cfg->metadata_max
+            || lfs2->cfg->metadata_max % lfs2->cfg->read_size == 0);
+    LFS2_ASSERT(!lfs2->cfg->metadata_max
+            || lfs2->cfg->metadata_max % lfs2->cfg->prog_size == 0);
+    LFS2_ASSERT(!lfs2->cfg->metadata_max
+            || lfs2->cfg->block_size % lfs2->cfg->metadata_max == 0);
 
     // setup read cache
     if (lfs2->cfg->read_buffer) {
@@ -4180,15 +4289,14 @@ static int lfs2_init(lfs2_t *lfs2, const struct lfs2_config *cfg) {
     lfs2_cache_zero(lfs2, &lfs2->rcache);
     lfs2_cache_zero(lfs2, &lfs2->pcache);
 
-    // setup lookahead, must be multiple of 64-bits, 32-bit aligned
+    // setup lookahead buffer, note mount finishes initializing this after
+    // we establish a decent pseudo-random seed
     LFS2_ASSERT(lfs2->cfg->lookahead_size > 0);
-    LFS2_ASSERT(lfs2->cfg->lookahead_size % 8 == 0 &&
-            (uintptr_t)lfs2->cfg->lookahead_buffer % 4 == 0);
     if (lfs2->cfg->lookahead_buffer) {
-        lfs2->free.buffer = lfs2->cfg->lookahead_buffer;
+        lfs2->lookahead.buffer = lfs2->cfg->lookahead_buffer;
     } else {
-        lfs2->free.buffer = lfs2_malloc(lfs2->cfg->lookahead_size);
-        if (!lfs2->free.buffer) {
+        lfs2->lookahead.buffer = lfs2_malloc(lfs2->cfg->lookahead_size);
+        if (!lfs2->lookahead.buffer) {
             err = LFS2_ERR_NOMEM;
             goto cleanup;
         }
@@ -4215,6 +4323,27 @@ static int lfs2_init(lfs2_t *lfs2, const struct lfs2_config *cfg) {
 
     LFS2_ASSERT(lfs2->cfg->metadata_max <= lfs2->cfg->block_size);
 
+    LFS2_ASSERT(lfs2->cfg->inline_max == (lfs2_size_t)-1
+            || lfs2->cfg->inline_max <= lfs2->cfg->cache_size);
+    LFS2_ASSERT(lfs2->cfg->inline_max == (lfs2_size_t)-1
+            || lfs2->cfg->inline_max <= lfs2->attr_max);
+    LFS2_ASSERT(lfs2->cfg->inline_max == (lfs2_size_t)-1
+            || lfs2->cfg->inline_max <= ((lfs2->cfg->metadata_max)
+                ? lfs2->cfg->metadata_max
+                : lfs2->cfg->block_size)/8);
+    lfs2->inline_max = lfs2->cfg->inline_max;
+    if (lfs2->inline_max == (lfs2_size_t)-1) {
+        lfs2->inline_max = 0;
+    } else if (lfs2->inline_max == 0) {
+        lfs2->inline_max = lfs2_min(
+                lfs2->cfg->cache_size,
+                lfs2_min(
+                    lfs2->attr_max,
+                    ((lfs2->cfg->metadata_max)
+                        ? lfs2->cfg->metadata_max
+                        : lfs2->cfg->block_size)/8));
+    }
+
     // setup default state
     lfs2->root[0] = LFS2_BLOCK_NULL;
     lfs2->root[1] = LFS2_BLOCK_NULL;
@@ -4245,7 +4374,7 @@ static int lfs2_deinit(lfs2_t *lfs2) {
     }
 
     if (!lfs2->cfg->lookahead_buffer) {
-        lfs2_free(lfs2->free.buffer);
+        lfs2_free(lfs2->lookahead.buffer);
     }
 
     return 0;
@@ -4254,7 +4383,7 @@ static int lfs2_deinit(lfs2_t *lfs2) {
 
 
 #ifndef LFS2_READONLY
-static int lfs2_rawformat(lfs2_t *lfs2, const struct lfs2_config *cfg) {
+static int lfs2_format_(lfs2_t *lfs2, const struct lfs2_config *cfg) {
     int err = 0;
     {
         err = lfs2_init(lfs2, cfg);
@@ -4265,12 +4394,12 @@ static int lfs2_rawformat(lfs2_t *lfs2, const struct lfs2_config *cfg) {
         LFS2_ASSERT(cfg->block_count != 0);
 
         // create free lookahead
-        memset(lfs2->free.buffer, 0, lfs2->cfg->lookahead_size);
-        lfs2->free.off = 0;
-        lfs2->free.size = lfs2_min(8*lfs2->cfg->lookahead_size,
+        memset(lfs2->lookahead.buffer, 0, lfs2->cfg->lookahead_size);
+        lfs2->lookahead.start = 0;
+        lfs2->lookahead.size = lfs2_min(8*lfs2->cfg->lookahead_size,
                 lfs2->block_count);
-        lfs2->free.i = 0;
-        lfs2_alloc_ack(lfs2);
+        lfs2->lookahead.next = 0;
+        lfs2_alloc_ckpoint(lfs2);
 
         // create root dir
         lfs2_mdir_t root;
@@ -4321,7 +4450,31 @@ cleanup:
 }
 #endif
 
-static int lfs2_rawmount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
+struct lfs2_tortoise_t {
+    lfs2_block_t pair[2];
+    lfs2_size_t i;
+    lfs2_size_t period;
+};
+
+static int lfs2_tortoise_detectcycles(
+    const lfs2_mdir_t *dir, struct lfs2_tortoise_t *tortoise) {
+    // detect cycles with Brent's algorithm
+    if (lfs2_pair_issync(dir->tail, tortoise->pair)) {
+        LFS2_WARN("Cycle detected in tail list");
+        return LFS2_ERR_CORRUPT;
+    }
+    if (tortoise->i == tortoise->period) {
+        tortoise->pair[0] = dir->tail[0];
+        tortoise->pair[1] = dir->tail[1];
+        tortoise->i = 0;
+        tortoise->period *= 2;
+    }
+    tortoise->i += 1;
+
+    return LFS2_ERR_OK;
+}
+
+static int lfs2_mount_(lfs2_t *lfs2, const struct lfs2_config *cfg) {
     int err = lfs2_init(lfs2, cfg);
     if (err) {
         return err;
@@ -4329,23 +4482,16 @@ static int lfs2_rawmount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
 
     // scan directory blocks for superblock and any global updates
     lfs2_mdir_t dir = {.tail = {0, 1}};
-    lfs2_block_t tortoise[2] = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL};
-    lfs2_size_t tortoise_i = 1;
-    lfs2_size_t tortoise_period = 1;
+    struct lfs2_tortoise_t tortoise = {
+        .pair = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
     while (!lfs2_pair_isnull(dir.tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs2_pair_issync(dir.tail, tortoise)) {
-            LFS2_WARN("Cycle detected in tail list");
-            err = LFS2_ERR_CORRUPT;
+        err = lfs2_tortoise_detectcycles(&dir, &tortoise);
+        if (err < 0) {
             goto cleanup;
         }
-        if (tortoise_i == tortoise_period) {
-            tortoise[0] = dir.tail[0];
-            tortoise[1] = dir.tail[1];
-            tortoise_i = 0;
-            tortoise_period *= 2;
-        }
-        tortoise_i += 1;
 
         // fetch next block in tail list
         lfs2_stag_t tag = lfs2_dir_fetchmatch(lfs2, &dir, dir.tail,
@@ -4394,6 +4540,7 @@ static int lfs2_rawmount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
             // found older minor version? set an in-device only bit in the
             // gstate so we know we need to rewrite the superblock before
             // the first write
+            bool needssuperblock = false;
             if (minor_version < lfs2_fs_disk_version_minor(lfs2)) {
                 LFS2_DEBUG("Found older minor version "
                         "v%"PRIu16".%"PRIu16" < v%"PRIu16".%"PRIu16,
@@ -4401,10 +4548,11 @@ static int lfs2_rawmount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
                         minor_version,
                         lfs2_fs_disk_version_major(lfs2),
                         lfs2_fs_disk_version_minor(lfs2));
-                // note this bit is reserved on disk, so fetching more gstate
-                // will not interfere here
-                lfs2_fs_prepsuperblock(lfs2, true);
+                needssuperblock = true;
             }
+            // note this bit is reserved on disk, so fetching more gstate
+            // will not interfere here
+            lfs2_fs_prepsuperblock(lfs2, needssuperblock);
 
             // check superblock configuration
             if (superblock.name_max) {
@@ -4438,6 +4586,9 @@ static int lfs2_rawmount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
                 }
 
                 lfs2->attr_max = superblock.attr_max;
+
+                // we also need to update inline_max in case attr_max changed
+                lfs2->inline_max = lfs2_min(lfs2->inline_max, lfs2->attr_max);
             }
 
             // this is where we get the block_count from disk if block_count=0
@@ -4478,23 +4629,23 @@ static int lfs2_rawmount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
 
     // setup free lookahead, to distribute allocations uniformly across
     // boots, we start the allocator at a random location
-    lfs2->free.off = lfs2->seed % lfs2->block_count;
+    lfs2->lookahead.start = lfs2->seed % lfs2->block_count;
     lfs2_alloc_drop(lfs2);
 
     return 0;
 
 cleanup:
-    lfs2_rawunmount(lfs2);
+    lfs2_unmount_(lfs2);
     return err;
 }
 
-static int lfs2_rawunmount(lfs2_t *lfs2) {
+static int lfs2_unmount_(lfs2_t *lfs2) {
     return lfs2_deinit(lfs2);
 }
 
 
 /// Filesystem filesystem operations ///
-static int lfs2_fs_rawstat(lfs2_t *lfs2, struct lfs2_fsinfo *fsinfo) {
+static int lfs2_fs_stat_(lfs2_t *lfs2, struct lfs2_fsinfo *fsinfo) {
     // if the superblock is up-to-date, we must be on the most recent
     // minor version of littlefs
     if (!lfs2_gstate_needssuperblock(&lfs2->gstate)) {
@@ -4534,7 +4685,7 @@ static int lfs2_fs_rawstat(lfs2_t *lfs2, struct lfs2_fsinfo *fsinfo) {
     return 0;
 }
 
-int lfs2_fs_rawtraverse(lfs2_t *lfs2,
+int lfs2_fs_traverse_(lfs2_t *lfs2,
         int (*cb)(void *data, lfs2_block_t block), void *data,
         bool includeorphans) {
     // iterate over metadata pairs
@@ -4553,22 +4704,17 @@ int lfs2_fs_rawtraverse(lfs2_t *lfs2,
     }
 #endif
 
-    lfs2_block_t tortoise[2] = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL};
-    lfs2_size_t tortoise_i = 1;
-    lfs2_size_t tortoise_period = 1;
+    struct lfs2_tortoise_t tortoise = {
+        .pair = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
+    int err = LFS2_ERR_OK;
     while (!lfs2_pair_isnull(dir.tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs2_pair_issync(dir.tail, tortoise)) {
-            LFS2_WARN("Cycle detected in tail list");
+        err = lfs2_tortoise_detectcycles(&dir, &tortoise);
+        if (err < 0) {
             return LFS2_ERR_CORRUPT;
         }
-        if (tortoise_i == tortoise_period) {
-            tortoise[0] = dir.tail[0];
-            tortoise[1] = dir.tail[1];
-            tortoise_i = 0;
-            tortoise_period *= 2;
-        }
-        tortoise_i += 1;
 
         for (int i = 0; i < 2; i++) {
             int err = cb(data, dir.tail[i]);
@@ -4647,22 +4793,17 @@ static int lfs2_fs_pred(lfs2_t *lfs2,
     // iterate over all directory directory entries
     pdir->tail[0] = 0;
     pdir->tail[1] = 1;
-    lfs2_block_t tortoise[2] = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL};
-    lfs2_size_t tortoise_i = 1;
-    lfs2_size_t tortoise_period = 1;
+    struct lfs2_tortoise_t tortoise = {
+        .pair = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
+    int err = LFS2_ERR_OK;
     while (!lfs2_pair_isnull(pdir->tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs2_pair_issync(pdir->tail, tortoise)) {
-            LFS2_WARN("Cycle detected in tail list");
+        err = lfs2_tortoise_detectcycles(pdir, &tortoise);
+        if (err < 0) {
             return LFS2_ERR_CORRUPT;
         }
-        if (tortoise_i == tortoise_period) {
-            tortoise[0] = pdir->tail[0];
-            tortoise[1] = pdir->tail[1];
-            tortoise_i = 0;
-            tortoise_period *= 2;
-        }
-        tortoise_i += 1;
 
         if (lfs2_pair_cmp(pdir->tail, pair) == 0) {
             return 0;
@@ -4712,22 +4853,17 @@ static lfs2_stag_t lfs2_fs_parent(lfs2_t *lfs2, const lfs2_block_t pair[2],
     // use fetchmatch with callback to find pairs
     parent->tail[0] = 0;
     parent->tail[1] = 1;
-    lfs2_block_t tortoise[2] = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL};
-    lfs2_size_t tortoise_i = 1;
-    lfs2_size_t tortoise_period = 1;
+    struct lfs2_tortoise_t tortoise = {
+        .pair = {LFS2_BLOCK_NULL, LFS2_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
+    int err = LFS2_ERR_OK;
     while (!lfs2_pair_isnull(parent->tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs2_pair_issync(parent->tail, tortoise)) {
-            LFS2_WARN("Cycle detected in tail list");
-            return LFS2_ERR_CORRUPT;
-        }
-        if (tortoise_i == tortoise_period) {
-            tortoise[0] = parent->tail[0];
-            tortoise[1] = parent->tail[1];
-            tortoise_i = 0;
-            tortoise_period *= 2;
+        err = lfs2_tortoise_detectcycles(parent, &tortoise);
+        if (err < 0) {
+            return err;
         }
-        tortoise_i += 1;
 
         lfs2_stag_t tag = lfs2_dir_fetchmatch(lfs2, parent, parent->tail,
                 LFS2_MKTAG(0x7ff, 0, 0x3ff),
@@ -4999,7 +5135,7 @@ static int lfs2_fs_forceconsistency(lfs2_t *lfs2) {
 #endif
 
 #ifndef LFS2_READONLY
-static int lfs2_fs_rawmkconsistent(lfs2_t *lfs2) {
+static int lfs2_fs_mkconsistent_(lfs2_t *lfs2) {
     // lfs2_fs_forceconsistency does most of the work here
     int err = lfs2_fs_forceconsistency(lfs2);
     if (err) {
@@ -5035,9 +5171,9 @@ static int lfs2_fs_size_count(void *p, lfs2_block_t block) {
     return 0;
 }
 
-static lfs2_ssize_t lfs2_fs_rawsize(lfs2_t *lfs2) {
+static lfs2_ssize_t lfs2_fs_size_(lfs2_t *lfs2) {
     lfs2_size_t size = 0;
-    int err = lfs2_fs_rawtraverse(lfs2, lfs2_fs_size_count, &size, false);
+    int err = lfs2_fs_traverse_(lfs2, lfs2_fs_size_count, &size, false);
     if (err) {
         return err;
     }
@@ -5045,8 +5181,59 @@ static lfs2_ssize_t lfs2_fs_rawsize(lfs2_t *lfs2) {
     return size;
 }
 
+// explicit garbage collection
 #ifndef LFS2_READONLY
-static int lfs2_fs_rawgrow(lfs2_t *lfs2, lfs2_size_t block_count) {
+static int lfs2_fs_gc_(lfs2_t *lfs2) {
+    // force consistency, even if we're not necessarily going to write,
+    // because this function is supposed to take care of janitorial work
+    // isn't it?
+    int err = lfs2_fs_forceconsistency(lfs2);
+    if (err) {
+        return err;
+    }
+
+    // try to compact metadata pairs, note we can't really accomplish
+    // anything if compact_thresh doesn't at least leave a prog_size
+    // available
+    if (lfs2->cfg->compact_thresh
+            < lfs2->cfg->block_size - lfs2->cfg->prog_size) {
+        // iterate over all mdirs
+        lfs2_mdir_t mdir = {.tail = {0, 1}};
+        while (!lfs2_pair_isnull(mdir.tail)) {
+            err = lfs2_dir_fetch(lfs2, &mdir, mdir.tail);
+            if (err) {
+                return err;
+            }
+
+            // not erased? exceeds our compaction threshold?
+            if (!mdir.erased || ((lfs2->cfg->compact_thresh == 0)
+                    ? mdir.off > lfs2->cfg->block_size - lfs2->cfg->block_size/8
+                    : mdir.off > lfs2->cfg->compact_thresh)) {
+                // the easiest way to trigger a compaction is to mark
+                // the mdir as unerased and add an empty commit
+                mdir.erased = false;
+                err = lfs2_dir_commit(lfs2, &mdir, NULL, 0);
+                if (err) {
+                    return err;
+                }
+            }
+        }
+    }
+
+    // try to populate the lookahead buffer, unless it's already full
+    if (lfs2->lookahead.size < 8*lfs2->cfg->lookahead_size) {
+        err = lfs2_alloc_scan(lfs2);
+        if (err) {
+            return err;
+        }
+    }
+
+    return 0;
+}
+#endif
+
+#ifndef LFS2_READONLY
+static int lfs2_fs_grow_(lfs2_t *lfs2, lfs2_size_t block_count) {
     // shrinking is not supported
     LFS2_ASSERT(block_count >= lfs2->block_count);
 
@@ -5451,10 +5638,10 @@ static int lfs21_mount(lfs2_t *lfs2, struct lfs21 *lfs21,
         lfs2->lfs21->root[1] = LFS2_BLOCK_NULL;
 
         // setup free lookahead
-        lfs2->free.off = 0;
-        lfs2->free.size = 0;
-        lfs2->free.i = 0;
-        lfs2_alloc_ack(lfs2);
+        lfs2->lookahead.start = 0;
+        lfs2->lookahead.size = 0;
+        lfs2->lookahead.next = 0;
+        lfs2_alloc_ckpoint(lfs2);
 
         // load superblock
         lfs21_dir_t dir;
@@ -5505,7 +5692,7 @@ static int lfs21_unmount(lfs2_t *lfs2) {
 }
 
 /// v1 migration ///
-static int lfs2_rawmigrate(lfs2_t *lfs2, const struct lfs2_config *cfg) {
+static int lfs2_migrate_(lfs2_t *lfs2, const struct lfs2_config *cfg) {
     struct lfs21 lfs21;
 
     // Indeterminate filesystem size not allowed for migration.
@@ -5759,7 +5946,7 @@ int lfs2_format(lfs2_t *lfs2, const struct lfs2_config *cfg) {
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32", "
-                ".block_cycles=%"PRIu32", .cache_size=%"PRIu32", "
+                ".block_cycles=%"PRId32", .cache_size=%"PRIu32", "
                 ".lookahead_size=%"PRIu32", .read_buffer=%p, "
                 ".prog_buffer=%p, .lookahead_buffer=%p, "
                 ".name_max=%"PRIu32", .file_max=%"PRIu32", "
@@ -5772,7 +5959,7 @@ int lfs2_format(lfs2_t *lfs2, const struct lfs2_config *cfg) {
             cfg->read_buffer, cfg->prog_buffer, cfg->lookahead_buffer,
             cfg->name_max, cfg->file_max, cfg->attr_max);
 
-    err = lfs2_rawformat(lfs2, cfg);
+    err = lfs2_format_(lfs2, cfg);
 
     LFS2_TRACE("lfs2_format -> %d", err);
     LFS2_UNLOCK(cfg);
@@ -5789,7 +5976,7 @@ int lfs2_mount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32", "
-                ".block_cycles=%"PRIu32", .cache_size=%"PRIu32", "
+                ".block_cycles=%"PRId32", .cache_size=%"PRIu32", "
                 ".lookahead_size=%"PRIu32", .read_buffer=%p, "
                 ".prog_buffer=%p, .lookahead_buffer=%p, "
                 ".name_max=%"PRIu32", .file_max=%"PRIu32", "
@@ -5802,7 +5989,7 @@ int lfs2_mount(lfs2_t *lfs2, const struct lfs2_config *cfg) {
             cfg->read_buffer, cfg->prog_buffer, cfg->lookahead_buffer,
             cfg->name_max, cfg->file_max, cfg->attr_max);
 
-    err = lfs2_rawmount(lfs2, cfg);
+    err = lfs2_mount_(lfs2, cfg);
 
     LFS2_TRACE("lfs2_mount -> %d", err);
     LFS2_UNLOCK(cfg);
@@ -5816,7 +6003,7 @@ int lfs2_unmount(lfs2_t *lfs2) {
     }
     LFS2_TRACE("lfs2_unmount(%p)", (void*)lfs2);
 
-    err = lfs2_rawunmount(lfs2);
+    err = lfs2_unmount_(lfs2);
 
     LFS2_TRACE("lfs2_unmount -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5831,7 +6018,7 @@ int lfs2_remove(lfs2_t *lfs2, const char *path) {
     }
     LFS2_TRACE("lfs2_remove(%p, \"%s\")", (void*)lfs2, path);
 
-    err = lfs2_rawremove(lfs2, path);
+    err = lfs2_remove_(lfs2, path);
 
     LFS2_TRACE("lfs2_remove -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5847,7 +6034,7 @@ int lfs2_rename(lfs2_t *lfs2, const char *oldpath, const char *newpath) {
     }
     LFS2_TRACE("lfs2_rename(%p, \"%s\", \"%s\")", (void*)lfs2, oldpath, newpath);
 
-    err = lfs2_rawrename(lfs2, oldpath, newpath);
+    err = lfs2_rename_(lfs2, oldpath, newpath);
 
     LFS2_TRACE("lfs2_rename -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5862,7 +6049,7 @@ int lfs2_stat(lfs2_t *lfs2, const char *path, struct lfs2_info *info) {
     }
     LFS2_TRACE("lfs2_stat(%p, \"%s\", %p)", (void*)lfs2, path, (void*)info);
 
-    err = lfs2_rawstat(lfs2, path, info);
+    err = lfs2_stat_(lfs2, path, info);
 
     LFS2_TRACE("lfs2_stat -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5878,7 +6065,7 @@ lfs2_ssize_t lfs2_getattr(lfs2_t *lfs2, const char *path,
     LFS2_TRACE("lfs2_getattr(%p, \"%s\", %"PRIu8", %p, %"PRIu32")",
             (void*)lfs2, path, type, buffer, size);
 
-    lfs2_ssize_t res = lfs2_rawgetattr(lfs2, path, type, buffer, size);
+    lfs2_ssize_t res = lfs2_getattr_(lfs2, path, type, buffer, size);
 
     LFS2_TRACE("lfs2_getattr -> %"PRId32, res);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5895,7 +6082,7 @@ int lfs2_setattr(lfs2_t *lfs2, const char *path,
     LFS2_TRACE("lfs2_setattr(%p, \"%s\", %"PRIu8", %p, %"PRIu32")",
             (void*)lfs2, path, type, buffer, size);
 
-    err = lfs2_rawsetattr(lfs2, path, type, buffer, size);
+    err = lfs2_setattr_(lfs2, path, type, buffer, size);
 
     LFS2_TRACE("lfs2_setattr -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5911,7 +6098,7 @@ int lfs2_removeattr(lfs2_t *lfs2, const char *path, uint8_t type) {
     }
     LFS2_TRACE("lfs2_removeattr(%p, \"%s\", %"PRIu8")", (void*)lfs2, path, type);
 
-    err = lfs2_rawremoveattr(lfs2, path, type);
+    err = lfs2_removeattr_(lfs2, path, type);
 
     LFS2_TRACE("lfs2_removeattr -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5926,10 +6113,10 @@ int lfs2_file_open(lfs2_t *lfs2, lfs2_file_t *file, const char *path, int flags)
         return err;
     }
     LFS2_TRACE("lfs2_file_open(%p, %p, \"%s\", %x)",
-            (void*)lfs2, (void*)file, path, flags);
+            (void*)lfs2, (void*)file, path, (unsigned)flags);
     LFS2_ASSERT(!lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    err = lfs2_file_rawopen(lfs2, file, path, flags);
+    err = lfs2_file_open_(lfs2, file, path, flags);
 
     LFS2_TRACE("lfs2_file_open -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5946,11 +6133,11 @@ int lfs2_file_opencfg(lfs2_t *lfs2, lfs2_file_t *file,
     }
     LFS2_TRACE("lfs2_file_opencfg(%p, %p, \"%s\", %x, %p {"
                  ".buffer=%p, .attrs=%p, .attr_count=%"PRIu32"})",
-            (void*)lfs2, (void*)file, path, flags,
+            (void*)lfs2, (void*)file, path, (unsigned)flags,
             (void*)cfg, cfg->buffer, (void*)cfg->attrs, cfg->attr_count);
     LFS2_ASSERT(!lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    err = lfs2_file_rawopencfg(lfs2, file, path, flags, cfg);
+    err = lfs2_file_opencfg_(lfs2, file, path, flags, cfg);
 
     LFS2_TRACE("lfs2_file_opencfg -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5965,7 +6152,7 @@ int lfs2_file_close(lfs2_t *lfs2, lfs2_file_t *file) {
     LFS2_TRACE("lfs2_file_close(%p, %p)", (void*)lfs2, (void*)file);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    err = lfs2_file_rawclose(lfs2, file);
+    err = lfs2_file_close_(lfs2, file);
 
     LFS2_TRACE("lfs2_file_close -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5981,7 +6168,7 @@ int lfs2_file_sync(lfs2_t *lfs2, lfs2_file_t *file) {
     LFS2_TRACE("lfs2_file_sync(%p, %p)", (void*)lfs2, (void*)file);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    err = lfs2_file_rawsync(lfs2, file);
+    err = lfs2_file_sync_(lfs2, file);
 
     LFS2_TRACE("lfs2_file_sync -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -5999,7 +6186,7 @@ lfs2_ssize_t lfs2_file_read(lfs2_t *lfs2, lfs2_file_t *file,
             (void*)lfs2, (void*)file, buffer, size);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    lfs2_ssize_t res = lfs2_file_rawread(lfs2, file, buffer, size);
+    lfs2_ssize_t res = lfs2_file_read_(lfs2, file, buffer, size);
 
     LFS2_TRACE("lfs2_file_read -> %"PRId32, res);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6017,7 +6204,7 @@ lfs2_ssize_t lfs2_file_write(lfs2_t *lfs2, lfs2_file_t *file,
             (void*)lfs2, (void*)file, buffer, size);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    lfs2_ssize_t res = lfs2_file_rawwrite(lfs2, file, buffer, size);
+    lfs2_ssize_t res = lfs2_file_write_(lfs2, file, buffer, size);
 
     LFS2_TRACE("lfs2_file_write -> %"PRId32, res);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6035,7 +6222,7 @@ lfs2_soff_t lfs2_file_seek(lfs2_t *lfs2, lfs2_file_t *file,
             (void*)lfs2, (void*)file, off, whence);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    lfs2_soff_t res = lfs2_file_rawseek(lfs2, file, off, whence);
+    lfs2_soff_t res = lfs2_file_seek_(lfs2, file, off, whence);
 
     LFS2_TRACE("lfs2_file_seek -> %"PRId32, res);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6052,7 +6239,7 @@ int lfs2_file_truncate(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t size) {
             (void*)lfs2, (void*)file, size);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    err = lfs2_file_rawtruncate(lfs2, file, size);
+    err = lfs2_file_truncate_(lfs2, file, size);
 
     LFS2_TRACE("lfs2_file_truncate -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6068,7 +6255,7 @@ lfs2_soff_t lfs2_file_tell(lfs2_t *lfs2, lfs2_file_t *file) {
     LFS2_TRACE("lfs2_file_tell(%p, %p)", (void*)lfs2, (void*)file);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    lfs2_soff_t res = lfs2_file_rawtell(lfs2, file);
+    lfs2_soff_t res = lfs2_file_tell_(lfs2, file);
 
     LFS2_TRACE("lfs2_file_tell -> %"PRId32, res);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6082,7 +6269,7 @@ int lfs2_file_rewind(lfs2_t *lfs2, lfs2_file_t *file) {
     }
     LFS2_TRACE("lfs2_file_rewind(%p, %p)", (void*)lfs2, (void*)file);
 
-    err = lfs2_file_rawrewind(lfs2, file);
+    err = lfs2_file_rewind_(lfs2, file);
 
     LFS2_TRACE("lfs2_file_rewind -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6097,9 +6284,9 @@ lfs2_soff_t lfs2_file_size(lfs2_t *lfs2, lfs2_file_t *file) {
     LFS2_TRACE("lfs2_file_size(%p, %p)", (void*)lfs2, (void*)file);
     LFS2_ASSERT(lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)file));
 
-    lfs2_soff_t res = lfs2_file_rawsize(lfs2, file);
+    lfs2_soff_t res = lfs2_file_size_(lfs2, file);
 
-    LFS2_TRACE("lfs2_file_size -> %"PRId32, res);
+    LFS2_TRACE("lfs2_file_size -> %"PRIu32, res);
     LFS2_UNLOCK(lfs2->cfg);
     return res;
 }
@@ -6112,7 +6299,7 @@ int lfs2_mkdir(lfs2_t *lfs2, const char *path) {
     }
     LFS2_TRACE("lfs2_mkdir(%p, \"%s\")", (void*)lfs2, path);
 
-    err = lfs2_rawmkdir(lfs2, path);
+    err = lfs2_mkdir_(lfs2, path);
 
     LFS2_TRACE("lfs2_mkdir -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6128,7 +6315,7 @@ int lfs2_dir_open(lfs2_t *lfs2, lfs2_dir_t *dir, const char *path) {
     LFS2_TRACE("lfs2_dir_open(%p, %p, \"%s\")", (void*)lfs2, (void*)dir, path);
     LFS2_ASSERT(!lfs2_mlist_isopen(lfs2->mlist, (struct lfs2_mlist*)dir));
 
-    err = lfs2_dir_rawopen(lfs2, dir, path);
+    err = lfs2_dir_open_(lfs2, dir, path);
 
     LFS2_TRACE("lfs2_dir_open -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6142,7 +6329,7 @@ int lfs2_dir_close(lfs2_t *lfs2, lfs2_dir_t *dir) {
     }
     LFS2_TRACE("lfs2_dir_close(%p, %p)", (void*)lfs2, (void*)dir);
 
-    err = lfs2_dir_rawclose(lfs2, dir);
+    err = lfs2_dir_close_(lfs2, dir);
 
     LFS2_TRACE("lfs2_dir_close -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6157,7 +6344,7 @@ int lfs2_dir_read(lfs2_t *lfs2, lfs2_dir_t *dir, struct lfs2_info *info) {
     LFS2_TRACE("lfs2_dir_read(%p, %p, %p)",
             (void*)lfs2, (void*)dir, (void*)info);
 
-    err = lfs2_dir_rawread(lfs2, dir, info);
+    err = lfs2_dir_read_(lfs2, dir, info);
 
     LFS2_TRACE("lfs2_dir_read -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6172,7 +6359,7 @@ int lfs2_dir_seek(lfs2_t *lfs2, lfs2_dir_t *dir, lfs2_off_t off) {
     LFS2_TRACE("lfs2_dir_seek(%p, %p, %"PRIu32")",
             (void*)lfs2, (void*)dir, off);
 
-    err = lfs2_dir_rawseek(lfs2, dir, off);
+    err = lfs2_dir_seek_(lfs2, dir, off);
 
     LFS2_TRACE("lfs2_dir_seek -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6186,7 +6373,7 @@ lfs2_soff_t lfs2_dir_tell(lfs2_t *lfs2, lfs2_dir_t *dir) {
     }
     LFS2_TRACE("lfs2_dir_tell(%p, %p)", (void*)lfs2, (void*)dir);
 
-    lfs2_soff_t res = lfs2_dir_rawtell(lfs2, dir);
+    lfs2_soff_t res = lfs2_dir_tell_(lfs2, dir);
 
     LFS2_TRACE("lfs2_dir_tell -> %"PRId32, res);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6200,7 +6387,7 @@ int lfs2_dir_rewind(lfs2_t *lfs2, lfs2_dir_t *dir) {
     }
     LFS2_TRACE("lfs2_dir_rewind(%p, %p)", (void*)lfs2, (void*)dir);
 
-    err = lfs2_dir_rawrewind(lfs2, dir);
+    err = lfs2_dir_rewind_(lfs2, dir);
 
     LFS2_TRACE("lfs2_dir_rewind -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6214,7 +6401,7 @@ int lfs2_fs_stat(lfs2_t *lfs2, struct lfs2_fsinfo *fsinfo) {
     }
     LFS2_TRACE("lfs2_fs_stat(%p, %p)", (void*)lfs2, (void*)fsinfo);
 
-    err = lfs2_fs_rawstat(lfs2, fsinfo);
+    err = lfs2_fs_stat_(lfs2, fsinfo);
 
     LFS2_TRACE("lfs2_fs_stat -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6228,7 +6415,7 @@ lfs2_ssize_t lfs2_fs_size(lfs2_t *lfs2) {
     }
     LFS2_TRACE("lfs2_fs_size(%p)", (void*)lfs2);
 
-    lfs2_ssize_t res = lfs2_fs_rawsize(lfs2);
+    lfs2_ssize_t res = lfs2_fs_size_(lfs2);
 
     LFS2_TRACE("lfs2_fs_size -> %"PRId32, res);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6243,7 +6430,7 @@ int lfs2_fs_traverse(lfs2_t *lfs2, int (*cb)(void *, lfs2_block_t), void *data)
     LFS2_TRACE("lfs2_fs_traverse(%p, %p, %p)",
             (void*)lfs2, (void*)(uintptr_t)cb, data);
 
-    err = lfs2_fs_rawtraverse(lfs2, cb, data, true);
+    err = lfs2_fs_traverse_(lfs2, cb, data, true);
 
     LFS2_TRACE("lfs2_fs_traverse -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6251,32 +6438,32 @@ int lfs2_fs_traverse(lfs2_t *lfs2, int (*cb)(void *, lfs2_block_t), void *data)
 }
 
 #ifndef LFS2_READONLY
-int lfs2_fs_gc(lfs2_t *lfs2) {
+int lfs2_fs_mkconsistent(lfs2_t *lfs2) {
     int err = LFS2_LOCK(lfs2->cfg);
     if (err) {
         return err;
     }
-    LFS2_TRACE("lfs2_fs_gc(%p)", (void*)lfs2);
+    LFS2_TRACE("lfs2_fs_mkconsistent(%p)", (void*)lfs2);
 
-    err = lfs2_fs_rawgc(lfs2);
+    err = lfs2_fs_mkconsistent_(lfs2);
 
-    LFS2_TRACE("lfs2_fs_gc -> %d", err);
+    LFS2_TRACE("lfs2_fs_mkconsistent -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
     return err;
 }
 #endif
 
 #ifndef LFS2_READONLY
-int lfs2_fs_mkconsistent(lfs2_t *lfs2) {
+int lfs2_fs_gc(lfs2_t *lfs2) {
     int err = LFS2_LOCK(lfs2->cfg);
     if (err) {
         return err;
     }
-    LFS2_TRACE("lfs2_fs_mkconsistent(%p)", (void*)lfs2);
+    LFS2_TRACE("lfs2_fs_gc(%p)", (void*)lfs2);
 
-    err = lfs2_fs_rawmkconsistent(lfs2);
+    err = lfs2_fs_gc_(lfs2);
 
-    LFS2_TRACE("lfs2_fs_mkconsistent -> %d", err);
+    LFS2_TRACE("lfs2_fs_gc -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
     return err;
 }
@@ -6290,7 +6477,7 @@ int lfs2_fs_grow(lfs2_t *lfs2, lfs2_size_t block_count) {
     }
     LFS2_TRACE("lfs2_fs_grow(%p, %"PRIu32")", (void*)lfs2, block_count);
 
-    err = lfs2_fs_rawgrow(lfs2, block_count);
+    err = lfs2_fs_grow_(lfs2, block_count);
 
     LFS2_TRACE("lfs2_fs_grow -> %d", err);
     LFS2_UNLOCK(lfs2->cfg);
@@ -6308,7 +6495,7 @@ int lfs2_migrate(lfs2_t *lfs2, const struct lfs2_config *cfg) {
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32", "
-                ".block_cycles=%"PRIu32", .cache_size=%"PRIu32", "
+                ".block_cycles=%"PRId32", .cache_size=%"PRIu32", "
                 ".lookahead_size=%"PRIu32", .read_buffer=%p, "
                 ".prog_buffer=%p, .lookahead_buffer=%p, "
                 ".name_max=%"PRIu32", .file_max=%"PRIu32", "
@@ -6321,7 +6508,7 @@ int lfs2_migrate(lfs2_t *lfs2, const struct lfs2_config *cfg) {
             cfg->read_buffer, cfg->prog_buffer, cfg->lookahead_buffer,
             cfg->name_max, cfg->file_max, cfg->attr_max);
 
-    err = lfs2_rawmigrate(lfs2, cfg);
+    err = lfs2_migrate_(lfs2, cfg);
 
     LFS2_TRACE("lfs2_migrate -> %d", err);
     LFS2_UNLOCK(cfg);
diff --git a/lib/littlefs/lfs2.h b/lib/littlefs/lfs2.h
index 4c426fc4c7..f503fd00bc 100644
--- a/lib/littlefs/lfs2.h
+++ b/lib/littlefs/lfs2.h
@@ -21,7 +21,7 @@ extern "C"
 // Software library version
 // Major (top-nibble), incremented on backwards incompatible changes
 // Minor (bottom-nibble), incremented on feature additions
-#define LFS2_VERSION 0x00020008
+#define LFS2_VERSION 0x0002000a
 #define LFS2_VERSION_MAJOR (0xffff & (LFS2_VERSION >> 16))
 #define LFS2_VERSION_MINOR (0xffff & (LFS2_VERSION >>  0))
 
@@ -52,16 +52,15 @@ typedef uint32_t lfs2_block_t;
 #endif
 
 // Maximum size of a file in bytes, may be redefined to limit to support other
-// drivers. Limited on disk to <= 4294967296. However, above 2147483647 the
-// functions lfs2_file_seek, lfs2_file_size, and lfs2_file_tell will return
-// incorrect values due to using signed integers. Stored in superblock and
-// must be respected by other littlefs drivers.
+// drivers. Limited on disk to <= 2147483647. Stored in superblock and must be
+// respected by other littlefs drivers.
 #ifndef LFS2_FILE_MAX
 #define LFS2_FILE_MAX 2147483647
 #endif
 
 // Maximum size of custom attributes in bytes, may be redefined, but there is
-// no real benefit to using a smaller LFS2_ATTR_MAX. Limited to <= 1022.
+// no real benefit to using a smaller LFS2_ATTR_MAX. Limited to <= 1022. Stored
+// in superblock and must be respected by other littlefs drivers.
 #ifndef LFS2_ATTR_MAX
 #define LFS2_ATTR_MAX 1022
 #endif
@@ -205,7 +204,8 @@ struct lfs2_config {
     // program sizes.
     lfs2_size_t block_size;
 
-    // Number of erasable blocks on the device.
+    // Number of erasable blocks on the device. Defaults to block_count stored
+    // on disk when zero.
     lfs2_size_t block_count;
 
     // Number of erase cycles before littlefs evicts metadata logs and moves
@@ -226,9 +226,20 @@ struct lfs2_config {
     // Size of the lookahead buffer in bytes. A larger lookahead buffer
     // increases the number of blocks found during an allocation pass. The
     // lookahead buffer is stored as a compact bitmap, so each byte of RAM
-    // can track 8 blocks. Must be a multiple of 8.
+    // can track 8 blocks.
     lfs2_size_t lookahead_size;
 
+    // Threshold for metadata compaction during lfs2_fs_gc in bytes. Metadata
+    // pairs that exceed this threshold will be compacted during lfs2_fs_gc.
+    // Defaults to ~88% block_size when zero, though the default may change
+    // in the future.
+    //
+    // Note this only affects lfs2_fs_gc. Normal compactions still only occur
+    // when full.
+    //
+    // Set to -1 to disable metadata compaction during lfs2_fs_gc.
+    lfs2_size_t compact_thresh;
+
     // Optional statically allocated read buffer. Must be cache_size.
     // By default lfs2_malloc is used to allocate this buffer.
     void *read_buffer;
@@ -237,25 +248,24 @@ struct lfs2_config {
     // By default lfs2_malloc is used to allocate this buffer.
     void *prog_buffer;
 
-    // Optional statically allocated lookahead buffer. Must be lookahead_size
-    // and aligned to a 32-bit boundary. By default lfs2_malloc is used to
-    // allocate this buffer.
+    // Optional statically allocated lookahead buffer. Must be lookahead_size.
+    // By default lfs2_malloc is used to allocate this buffer.
     void *lookahead_buffer;
 
     // Optional upper limit on length of file names in bytes. No downside for
     // larger names except the size of the info struct which is controlled by
-    // the LFS2_NAME_MAX define. Defaults to LFS2_NAME_MAX when zero. Stored in
-    // superblock and must be respected by other littlefs drivers.
+    // the LFS2_NAME_MAX define. Defaults to LFS2_NAME_MAX or name_max stored on
+    // disk when zero.
     lfs2_size_t name_max;
 
     // Optional upper limit on files in bytes. No downside for larger files
-    // but must be <= LFS2_FILE_MAX. Defaults to LFS2_FILE_MAX when zero. Stored
-    // in superblock and must be respected by other littlefs drivers.
+    // but must be <= LFS2_FILE_MAX. Defaults to LFS2_FILE_MAX or file_max stored
+    // on disk when zero.
     lfs2_size_t file_max;
 
     // Optional upper limit on custom attributes in bytes. No downside for
     // larger attributes size but must be <= LFS2_ATTR_MAX. Defaults to
-    // LFS2_ATTR_MAX when zero.
+    // LFS2_ATTR_MAX or attr_max stored on disk when zero.
     lfs2_size_t attr_max;
 
     // Optional upper limit on total space given to metadata pairs in bytes. On
@@ -264,6 +274,15 @@ struct lfs2_config {
     // Defaults to block_size when zero.
     lfs2_size_t metadata_max;
 
+    // Optional upper limit on inlined files in bytes. Inlined files live in
+    // metadata and decrease storage requirements, but may be limited to
+    // improve metadata-related performance. Must be <= cache_size, <=
+    // attr_max, and <= block_size/8. Defaults to the largest possible
+    // inline_max when zero.
+    //
+    // Set to -1 to disable inlined files.
+    lfs2_size_t inline_max;
+
 #ifdef LFS2_MULTIVERSION
     // On-disk version to use when writing in the form of 16-bit major version
     // + 16-bit minor version. This limiting metadata to what is supported by
@@ -430,19 +449,20 @@ typedef struct lfs2 {
     lfs2_gstate_t gdisk;
     lfs2_gstate_t gdelta;
 
-    struct lfs2_free {
-        lfs2_block_t off;
+    struct lfs2_lookahead {
+        lfs2_block_t start;
         lfs2_block_t size;
-        lfs2_block_t i;
-        lfs2_block_t ack;
-        uint32_t *buffer;
-    } free;
+        lfs2_block_t next;
+        lfs2_block_t ckpoint;
+        uint8_t *buffer;
+    } lookahead;
 
     const struct lfs2_config *cfg;
     lfs2_size_t block_count;
     lfs2_size_t name_max;
     lfs2_size_t file_max;
     lfs2_size_t attr_max;
+    lfs2_size_t inline_max;
 
 #ifdef LFS2_MIGRATE
     struct lfs21 *lfs21;
@@ -712,18 +732,6 @@ lfs2_ssize_t lfs2_fs_size(lfs2_t *lfs2);
 // Returns a negative error code on failure.
 int lfs2_fs_traverse(lfs2_t *lfs2, int (*cb)(void*, lfs2_block_t), void *data);
 
-// Attempt to proactively find free blocks
-//
-// Calling this function is not required, but may allowing the offloading of
-// the expensive block allocation scan to a less time-critical code path.
-//
-// Note: littlefs currently does not persist any found free blocks to disk.
-// This may change in the future.
-//
-// Returns a negative error code on failure. Finding no free blocks is
-// not an error.
-int lfs2_fs_gc(lfs2_t *lfs2);
-
 #ifndef LFS2_READONLY
 // Attempt to make the filesystem consistent and ready for writing
 //
@@ -737,6 +745,24 @@ int lfs2_fs_mkconsistent(lfs2_t *lfs2);
 #endif
 
 #ifndef LFS2_READONLY
+// Attempt any janitorial work
+//
+// This currently:
+// 1. Calls mkconsistent if not already consistent
+// 2. Compacts metadata > compact_thresh
+// 3. Populates the block allocator
+//
+// Though additional janitorial work may be added in the future.
+//
+// Calling this function is not required, but may allow the offloading of
+// expensive janitorial work to a less time-critical code path.
+//
+// Returns a negative error code on failure. Accomplishing nothing is not
+// an error.
+int lfs2_fs_gc(lfs2_t *lfs2);
+#endif
+
+#ifndef LFS2_READONLY
 // Grows the filesystem to a new size, updating the superblock with the new
 // block count.
 //
diff --git a/lib/littlefs/lfs2_util.c b/lib/littlefs/lfs2_util.c
index c9850e7886..4fe7e5340c 100644
--- a/lib/littlefs/lfs2_util.c
+++ b/lib/littlefs/lfs2_util.c
@@ -11,6 +11,8 @@
 #ifndef LFS2_CONFIG
 
 
+// If user provides their own CRC impl we don't need this
+#ifndef LFS2_CRC
 // Software CRC implementation with small lookup table
 uint32_t lfs2_crc(uint32_t crc, const void *buffer, size_t size) {
     static const uint32_t rtable[16] = {
@@ -29,6 +31,7 @@ uint32_t lfs2_crc(uint32_t crc, const void *buffer, size_t size) {
 
     return crc;
 }
+#endif
 
 
 #endif
diff --git a/lib/littlefs/lfs2_util.h b/lib/littlefs/lfs2_util.h
index dd2cbcc106..48d9f4c572 100644
--- a/lib/littlefs/lfs2_util.h
+++ b/lib/littlefs/lfs2_util.h
@@ -8,6 +8,9 @@
 #ifndef LFS2_UTIL_H
 #define LFS2_UTIL_H
 
+#define LFS2_STRINGIZE(x) LFS2_STRINGIZE2(x)
+#define LFS2_STRINGIZE2(x) #x
+
 // Users can override lfs2_util.h with their own configuration by defining
 // LFS2_CONFIG as a header file to include (-DLFS2_CONFIG=lfs2_config.h).
 //
@@ -15,11 +18,26 @@
 // provided by the config file. To start, I would suggest copying lfs2_util.h
 // and modifying as needed.
 #ifdef LFS2_CONFIG
-#define LFS2_STRINGIZE(x) LFS2_STRINGIZE2(x)
-#define LFS2_STRINGIZE2(x) #x
 #include LFS2_STRINGIZE(LFS2_CONFIG)
 #else
 
+// Alternatively, users can provide a header file which defines
+// macros and other things consumed by littlefs.
+//
+// For example, provide my_defines.h, which contains
+// something like:
+//
+// #include <stddef.h>
+// extern void *my_malloc(size_t sz);
+// #define LFS2_MALLOC(sz) my_malloc(sz)
+//
+// And build littlefs with the header by defining LFS2_DEFINES.
+// (-DLFS2_DEFINES=my_defines.h)
+
+#ifdef LFS2_DEFINES
+#include LFS2_STRINGIZE(LFS2_DEFINES)
+#endif
+
 // System includes
 #include <stdint.h>
 #include <stdbool.h>
@@ -212,12 +230,22 @@ static inline uint32_t lfs2_tobe32(uint32_t a) {
 }
 
 // Calculate CRC-32 with polynomial = 0x04c11db7
+#ifdef LFS2_CRC
+uint32_t lfs2_crc(uint32_t crc, const void *buffer, size_t size) {
+    return LFS2_CRC(crc, buffer, size)
+}
+#else
 uint32_t lfs2_crc(uint32_t crc, const void *buffer, size_t size);
+#endif
 
 // Allocate memory, only used if buffers are not provided to littlefs
-// Note, memory must be 64-bit aligned
+//
+// littlefs current has no alignment requirements, as it only allocates
+// byte-level buffers.
 static inline void *lfs2_malloc(size_t size) {
-#ifndef LFS2_NO_MALLOC
+#if defined(LFS2_MALLOC)
+    return LFS2_MALLOC(size);
+#elif !defined(LFS2_NO_MALLOC)
     return malloc(size);
 #else
     (void)size;
@@ -227,7 +255,9 @@ static inline void *lfs2_malloc(size_t size) {
 
 // Deallocate memory, only used if buffers are not provided to littlefs
 static inline void lfs2_free(void *p) {
-#ifndef LFS2_NO_MALLOC
+#if defined(LFS2_FREE)
+    LFS2_FREE(p);
+#elif !defined(LFS2_NO_MALLOC)
     free(p);
 #else
     (void)p;
diff --git a/tests/extmod/vfs_lfs.py b/tests/extmod/vfs_lfs.py
index 3ad57fd9c3..40d58e9c9f 100644
--- a/tests/extmod/vfs_lfs.py
+++ b/tests/extmod/vfs_lfs.py
@@ -136,7 +136,7 @@ def test(bdev, vfs_class):
     print(fs.getcwd())
     fs.chdir("../testdir")
     print(fs.getcwd())
-    fs.chdir("../..")
+    fs.chdir("..")
     print(fs.getcwd())
     fs.chdir(".//testdir")
     print(fs.getcwd())