Merge pull request #1084 from elupus/fix/packing

fix: avoid assuming struct packing

.github/workflows/test.yml

@@ -273,7 +273,6 @@ jobs:
             }' | tee status/$(basename $f .csv).json
           done
       - name: upload-status-sizes
-        if: ${{matrix.arch == 'x86_64'}}
         uses: actions/upload-artifact@v4
         with:
           name: status-sizes-${{matrix.arch}}
@@ -375,6 +374,29 @@ jobs:
         run: |
           CFLAGS="$CFLAGS -DLFS_NO_INTRINSICS" make test
 
+  # run with all trace options enabled to at least make sure these
+  # all compile
+  test-yes-trace:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: install
+        run: |
+          # need a few things
+          sudo apt-get update -qq
+          sudo apt-get install -qq gcc python3 python3-pip
+          pip3 install toml
+          gcc --version
+          python3 --version
+      - name: test-yes-trace
+        run: |
+          CFLAGS="$CFLAGS \
+            -DLFS_YES_TRACE \
+            -DLFS_RAMBD_YES_TRACE \
+            -DLFS_FILEBD_YES_TRACE \
+            -DLFS_RAMBD_YES_TRACE" \
+            make test
+
   # run LFS_MULTIVERSION tests
   test-multiversion:
     runs-on: ubuntu-latest

README.md

@@ -199,6 +199,47 @@ The tests assume a Linux environment and can be started with make:
 make test
 ```
 
+Tests are implemented in C in the .toml files found in the `tests` directory.
+When developing a feature or fixing a bug, it is frequently useful to run a
+single test case or suite of tests:
+
+``` bash
+./scripts/test.py -l runners/test_runner  # list available test suites
+./scripts/test.py -L runners/test_runner test_dirs  # list available test cases
+./scripts/test.py runners/test_runner test_dirs  # run a specific test suite
+```
+
+If an assert fails in a test, test.py will try to print information about the
+failure:
+
+``` bash
+tests/test_dirs.toml:1:failure: test_dirs_root:1g12gg2 (PROG_SIZE=16, ERASE_SIZE=512) failed
+tests/test_dirs.toml:5:assert: assert failed with 0, expected eq 42
+    lfs_mount(&lfs, cfg) => 42;
+```
+
+This includes the test id, which can be passed to test.py to run only that
+specific test permutation:
+
+``` bash
+./scripts/test.py runners/test_runner test_dirs_root:1g12gg2  # run a specific test permutation
+./scripts/test.py runners/test_runner test_dirs_root:1g12gg2 --gdb  # drop into gdb on failure
+```
+
+Some other flags that may be useful:
+
+```bash
+./scripts/test.py runners/test_runner -b -j  # run tests in parallel
+./scripts/test.py runners/test_runner -v -O-  # redirect stdout to stdout
+./scripts/test.py runners/test_runner -ddisk  # capture resulting disk image
+```
+
+See `-h/--help` for a full list of available flags:
+
+``` bash
+./scripts/test.py --help
+```
+
 ## License
 
 The littlefs is provided under the [BSD-3-Clause] license. See
@@ -251,6 +292,12 @@ License Identifiers that are here available: http://spdx.org/licenses/
   filesystem over USB. Allows mounting littlefs on a host PC without additional
   drivers.
 
+- [ramcrc32bd] - An example block device using littlefs's 32-bit CRC for
+  error-correction.
+
+- [ramrsbd] - An example block device using Reed-Solomon codes for
+  error-correction.
+
 - [Mbed OS] - The easiest way to get started with littlefs is to jump into Mbed
   which already has block device drivers for most forms of embedded storage.
   littlefs is available in Mbed OS as the [LittleFileSystem] class.
@@ -281,6 +328,8 @@ License Identifiers that are here available: http://spdx.org/licenses/
 [mklfs]: https://github.com/whitecatboard/Lua-RTOS-ESP32/tree/master/components/mklfs/src
 [mklittlefs]: https://github.com/earlephilhower/mklittlefs
 [pico-littlefs-usb]: https://github.com/oyama/pico-littlefs-usb
+[ramcrc32bd]: https://github.com/geky/ramcrc32bd
+[ramrsbd]: https://github.com/geky/ramrsbd
 [Mbed OS]: https://github.com/armmbed/mbed-os
 [LittleFileSystem]: https://os.mbed.com/docs/mbed-os/latest/apis/littlefilesystem.html
 [SPIFFS]: https://github.com/pellepl/spiffs

bd/lfs_filebd.c

@@ -133,7 +133,7 @@ int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
 
 int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block) {
     LFS_FILEBD_TRACE("lfs_filebd_erase(%p, 0x%"PRIx32" (%"PRIu32"))",
-            (void*)cfg, block, ((lfs_file_t*)cfg->context)->cfg->erase_size);
+            (void*)cfg, block, ((lfs_filebd_t*)cfg->context)->cfg->erase_size);
     lfs_filebd_t *bd = cfg->context;
 
     // check if erase is valid

lfs.c

@@ -282,6 +282,21 @@ static int lfs_bd_erase(lfs_t *lfs, lfs_block_t block) {
 
 
 /// Small type-level utilities ///
+
+// some operations on paths
+static inline lfs_size_t lfs_path_namelen(const char *path) {
+    return strcspn(path, "/");
+}
+
+static inline bool lfs_path_islast(const char *path) {
+    lfs_size_t namelen = lfs_path_namelen(path);
+    return path[namelen + strspn(path + namelen, "/")] == '\0';
+}
+
+static inline bool lfs_path_isdir(const char *path) {
+    return path[lfs_path_namelen(path)] != '\0';
+}
+
 // operations on block pairs
 static inline void lfs_pair_swap(lfs_block_t pair[2]) {
     lfs_block_t t = pair[0];
@@ -389,18 +404,15 @@ struct lfs_diskoff {
 
 // operations on global state
 static inline void lfs_gstate_xor(lfs_gstate_t *a, const lfs_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 lfs_gstate_iszero(const lfs_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 LFS_READONLY
@@ -1461,32 +1473,46 @@ static int lfs_dir_find_match(void *data,
     return LFS_CMP_EQ;
 }
 
+// lfs_dir_find tries to set path and id even if file is not found
+//
+// returns:
+// - 0                  if file is found
+// - LFS_ERR_NOENT      if file or parent is not found
+// - LFS_ERR_NOTDIR     if parent is not a dir
 static lfs_stag_t lfs_dir_find(lfs_t *lfs, lfs_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
     lfs_stag_t tag = LFS_MKTAG(LFS_TYPE_DIR, 0x3ff, 0);
     dir->tail[0] = lfs->root[0];
     dir->tail[1] = lfs->root[1];
 
+    // empty paths are not allowed
+    if (*name == '\0') {
+        return LFS_ERR_INVAL;
+    }
+
     while (true) {
 nextname:
-        // skip slashes
-        name += strspn(name, "/");
+        // skip slashes if we're a directory
+        if (lfs_tag_type3(tag) == LFS_TYPE_DIR) {
+            name += strspn(name, "/");
+        }
         lfs_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 LFS_ERR_INVAL;
+        }
+
         // skip if matched by '..' in name
         const char *suffix = name + namelen;
         lfs_size_t sufflen;
@@ -1498,7 +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;
@@ -1512,14 +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 (lfs_tag_type3(tag) != LFS_TYPE_DIR) {
             return LFS_ERR_NOTDIR;
         }
@@ -1539,8 +1567,7 @@ nextname:
             tag = lfs_dir_fetchmatch(lfs, dir, dir->tail,
                     LFS_MKTAG(0x780, 0, 0),
                     LFS_MKTAG(LFS_TYPE_NAME, 0, namelen),
-                     // are we last name?
-                    (strchr(name, '/') == NULL) ? id : NULL,
+                    id,
                     lfs_dir_find_match, &(struct lfs_dir_find_match){
                         lfs, name, namelen});
             if (tag < 0) {
@@ -2128,13 +2155,14 @@ static int lfs_dir_splittingcompact(lfs_t *lfs, lfs_mdir_t *dir,
             // And we cap at half a block to avoid degenerate cases with
             // nearly-full metadata blocks.
             //
+            lfs_size_t metadata_max = (lfs->cfg->metadata_max)
+                    ? lfs->cfg->metadata_max
+                    : lfs->cfg->block_size;
             if (end - split < 0xff
                     && size <= lfs_min(
-                        lfs->cfg->block_size - 40,
+                        metadata_max - 40,
                         lfs_alignup(
-                            (lfs->cfg->metadata_max
-                                ? lfs->cfg->metadata_max
-                                : lfs->cfg->block_size)/2,
+                            metadata_max/2,
                             lfs->cfg->prog_size))) {
                 break;
             }
@@ -2338,7 +2366,8 @@ fixmlist:;
             if (d->m.pair != pair) {
                 for (int i = 0; i < attrcount; i++) {
                     if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_DELETE &&
-                            d->id == lfs_tag_id(attrs[i].tag)) {
+                            d->id == lfs_tag_id(attrs[i].tag) &&
+                            d->type != LFS_TYPE_DIR) {
                         d->m.pair[0] = LFS_BLOCK_NULL;
                         d->m.pair[1] = LFS_BLOCK_NULL;
                     } else if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_DELETE &&
@@ -2527,7 +2556,7 @@ static int lfs_dir_orphaningcommit(lfs_t *lfs, lfs_mdir_t *dir,
         if (err != LFS_ERR_NOENT) {
             if (lfs_gstate_hasorphans(&lfs->gstate)) {
                 // next step, clean up orphans
-                err = lfs_fs_preporphans(lfs, -hasparent);
+                err = lfs_fs_preporphans(lfs, -(int8_t)hasparent);
                 if (err) {
                     return err;
                 }
@@ -2603,12 +2632,12 @@ static int lfs_mkdir_(lfs_t *lfs, const char *path) {
     cwd.next = lfs->mlist;
     uint16_t id;
     err = lfs_dir_find(lfs, &cwd.m, &path, &id);
-    if (!(err == LFS_ERR_NOENT && id != 0x3ff)) {
+    if (!(err == LFS_ERR_NOENT && lfs_path_islast(path))) {
         return (err < 0) ? err : LFS_ERR_EXIST;
     }
 
     // check that name fits
-    lfs_size_t nlen = strlen(path);
+    lfs_size_t nlen = lfs_path_namelen(path);
     if (nlen > lfs->name_max) {
         return LFS_ERR_NAMETOOLONG;
     }
@@ -3057,7 +3086,7 @@ static int lfs_file_opencfg_(lfs_t *lfs, lfs_file_t *file,
 
     // allocate entry for file if it doesn't exist
     lfs_stag_t tag = lfs_dir_find(lfs, &file->m, &path, &file->id);
-    if (tag < 0 && !(tag == LFS_ERR_NOENT && file->id != 0x3ff)) {
+    if (tag < 0 && !(tag == LFS_ERR_NOENT && lfs_path_islast(path))) {
         err = tag;
         goto cleanup;
     }
@@ -3077,8 +3106,14 @@ static int lfs_file_opencfg_(lfs_t *lfs, lfs_file_t *file,
             goto cleanup;
         }
 
+        // don't allow trailing slashes
+        if (lfs_path_isdir(path)) {
+            err = LFS_ERR_NOTDIR;
+            goto cleanup;
+        }
+
         // check that name fits
-        lfs_size_t nlen = strlen(path);
+        lfs_size_t nlen = lfs_path_namelen(path);
         if (nlen > lfs->name_max) {
             err = LFS_ERR_NAMETOOLONG;
             goto cleanup;
@@ -3688,13 +3723,8 @@ static lfs_soff_t lfs_file_seek_(lfs_t *lfs, lfs_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 LFS_READONLY
-        !(file->flags & LFS_F_WRITING)
-#else
-        true
-#endif
-            ) {
+    if ((file->flags & LFS_F_READING)
+            && file->off != lfs->cfg->block_size) {
         int oindex = lfs_ctz_index(lfs, &(lfs_off_t){file->pos});
         lfs_off_t noff = npos;
         int nindex = lfs_ctz_index(lfs, &noff);
@@ -3836,6 +3866,12 @@ static int lfs_stat_(lfs_t *lfs, const char *path, struct lfs_info *info) {
         return (int)tag;
     }
 
+    // only allow trailing slashes on dirs
+    if (strchr(path, '/') != NULL
+            && lfs_tag_type3(tag) != LFS_TYPE_DIR) {
+        return LFS_ERR_NOTDIR;
+    }
+
     return lfs_dir_getinfo(lfs, &cwd, lfs_tag_id(tag), info);
 }
 
@@ -3938,7 +3974,7 @@ static int lfs_rename_(lfs_t *lfs, const char *oldpath, const char *newpath) {
     uint16_t newid;
     lfs_stag_t prevtag = lfs_dir_find(lfs, &newcwd, &newpath, &newid);
     if ((prevtag < 0 || lfs_tag_id(prevtag) == 0x3ff) &&
-            !(prevtag == LFS_ERR_NOENT && newid != 0x3ff)) {
+            !(prevtag == LFS_ERR_NOENT && lfs_path_islast(newpath))) {
         return (prevtag < 0) ? (int)prevtag : LFS_ERR_INVAL;
     }
 
@@ -3949,8 +3985,14 @@ static int lfs_rename_(lfs_t *lfs, const char *oldpath, const char *newpath) {
     struct lfs_mlist prevdir;
     prevdir.next = lfs->mlist;
     if (prevtag == LFS_ERR_NOENT) {
+        // if we're a file, don't allow trailing slashes
+        if (lfs_path_isdir(newpath)
+                && lfs_tag_type3(oldtag) != LFS_TYPE_DIR) {
+            return LFS_ERR_NOTDIR;
+        }
+
         // check that name fits
-        lfs_size_t nlen = strlen(newpath);
+        lfs_size_t nlen = lfs_path_namelen(newpath);
         if (nlen > lfs->name_max) {
             return LFS_ERR_NAMETOOLONG;
         }
@@ -4010,7 +4052,8 @@ static int lfs_rename_(lfs_t *lfs, const char *oldpath, const char *newpath) {
             {LFS_MKTAG_IF(prevtag != LFS_ERR_NOENT,
                 LFS_TYPE_DELETE, newid, 0), NULL},
             {LFS_MKTAG(LFS_TYPE_CREATE, newid, 0), NULL},
-            {LFS_MKTAG(lfs_tag_type3(oldtag), newid, strlen(newpath)), newpath},
+            {LFS_MKTAG(lfs_tag_type3(oldtag),
+                newid, lfs_path_namelen(newpath)), newpath},
             {LFS_MKTAG(LFS_FROM_MOVE, newid, lfs_tag_id(oldtag)), &oldcwd},
             {LFS_MKTAG_IF(samepair,
                 LFS_TYPE_DELETE, newoldid, 0), NULL}));
@@ -4167,6 +4210,14 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     // which littlefs currently does not support
     LFS_ASSERT((bool)0x80000000);
 
+    // check that the required io functions are provided
+    LFS_ASSERT(lfs->cfg->read != NULL);
+#ifndef LFS_READONLY
+    LFS_ASSERT(lfs->cfg->prog != NULL);
+    LFS_ASSERT(lfs->cfg->erase != NULL);
+    LFS_ASSERT(lfs->cfg->sync != NULL);
+#endif
+
     // validate that the lfs-cfg sizes were initiated properly before
     // performing any arithmetic logics with them
     LFS_ASSERT(lfs->cfg->read_size != 0);
@@ -4203,6 +4254,15 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     LFS_ASSERT(lfs->cfg->compact_thresh == (lfs_size_t)-1
             || lfs->cfg->compact_thresh <= lfs->cfg->block_size);
 
+    // check that metadata_max is a multiple of read_size and prog_size,
+    // and a factor of the block_size
+    LFS_ASSERT(!lfs->cfg->metadata_max
+            || lfs->cfg->metadata_max % lfs->cfg->read_size == 0);
+    LFS_ASSERT(!lfs->cfg->metadata_max
+            || lfs->cfg->metadata_max % lfs->cfg->prog_size == 0);
+    LFS_ASSERT(!lfs->cfg->metadata_max
+            || lfs->cfg->block_size % lfs->cfg->metadata_max == 0);
+
     // setup read cache
     if (lfs->cfg->read_buffer) {
         lfs->rcache.buffer = lfs->cfg->read_buffer;
@@ -4390,6 +4450,30 @@ cleanup:
 }
 #endif
 
+struct lfs_tortoise_t {
+    lfs_block_t pair[2];
+    lfs_size_t i;
+    lfs_size_t period;
+};
+
+static int lfs_tortoise_detectcycles(
+    const lfs_mdir_t *dir, struct lfs_tortoise_t *tortoise) {
+    // detect cycles with Brent's algorithm
+    if (lfs_pair_issync(dir->tail, tortoise->pair)) {
+        LFS_WARN("Cycle detected in tail list");
+        return LFS_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 LFS_ERR_OK;
+}
+
 static int lfs_mount_(lfs_t *lfs, const struct lfs_config *cfg) {
     int err = lfs_init(lfs, cfg);
     if (err) {
@@ -4398,23 +4482,16 @@ static int lfs_mount_(lfs_t *lfs, const struct lfs_config *cfg) {
 
     // scan directory blocks for superblock and any global updates
     lfs_mdir_t dir = {.tail = {0, 1}};
-    lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
-    lfs_size_t tortoise_i = 1;
-    lfs_size_t tortoise_period = 1;
+    struct lfs_tortoise_t tortoise = {
+        .pair = {LFS_BLOCK_NULL, LFS_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
     while (!lfs_pair_isnull(dir.tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs_pair_issync(dir.tail, tortoise)) {
-            LFS_WARN("Cycle detected in tail list");
-            err = LFS_ERR_CORRUPT;
+        err = lfs_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
         lfs_stag_t tag = lfs_dir_fetchmatch(lfs, &dir, dir.tail,
@@ -4627,22 +4704,17 @@ int lfs_fs_traverse_(lfs_t *lfs,
     }
 #endif
 
-    lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
-    lfs_size_t tortoise_i = 1;
-    lfs_size_t tortoise_period = 1;
+    struct lfs_tortoise_t tortoise = {
+        .pair = {LFS_BLOCK_NULL, LFS_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
+    int err = LFS_ERR_OK;
     while (!lfs_pair_isnull(dir.tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs_pair_issync(dir.tail, tortoise)) {
-            LFS_WARN("Cycle detected in tail list");
+        err = lfs_tortoise_detectcycles(&dir, &tortoise);
+        if (err < 0) {
             return LFS_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]);
@@ -4721,22 +4793,17 @@ static int lfs_fs_pred(lfs_t *lfs,
     // iterate over all directory directory entries
     pdir->tail[0] = 0;
     pdir->tail[1] = 1;
-    lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
-    lfs_size_t tortoise_i = 1;
-    lfs_size_t tortoise_period = 1;
+    struct lfs_tortoise_t tortoise = {
+        .pair = {LFS_BLOCK_NULL, LFS_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
+    int err = LFS_ERR_OK;
     while (!lfs_pair_isnull(pdir->tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs_pair_issync(pdir->tail, tortoise)) {
-            LFS_WARN("Cycle detected in tail list");
+        err = lfs_tortoise_detectcycles(pdir, &tortoise);
+        if (err < 0) {
             return LFS_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 (lfs_pair_cmp(pdir->tail, pair) == 0) {
             return 0;
@@ -4786,22 +4853,17 @@ static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t pair[2],
     // use fetchmatch with callback to find pairs
     parent->tail[0] = 0;
     parent->tail[1] = 1;
-    lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
-    lfs_size_t tortoise_i = 1;
-    lfs_size_t tortoise_period = 1;
+    struct lfs_tortoise_t tortoise = {
+        .pair = {LFS_BLOCK_NULL, LFS_BLOCK_NULL},
+        .i = 1,
+        .period = 1,
+    };
+    int err = LFS_ERR_OK;
     while (!lfs_pair_isnull(parent->tail)) {
-        // detect cycles with Brent's algorithm
-        if (lfs_pair_issync(parent->tail, tortoise)) {
-            LFS_WARN("Cycle detected in tail list");
-            return LFS_ERR_CORRUPT;
+        err = lfs_tortoise_detectcycles(parent, &tortoise);
+        if (err < 0) {
+            return err;
         }
-        if (tortoise_i == tortoise_period) {
-            tortoise[0] = parent->tail[0];
-            tortoise[1] = parent->tail[1];
-            tortoise_i = 0;
-            tortoise_period *= 2;
-        }
-        tortoise_i += 1;
 
         lfs_stag_t tag = lfs_dir_fetchmatch(lfs, parent, parent->tail,
                 LFS_MKTAG(0x7ff, 0, 0x3ff),
@@ -5884,7 +5946,7 @@ int lfs_format(lfs_t *lfs, const struct lfs_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", "
@@ -5914,7 +5976,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_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", "
@@ -6051,7 +6113,7 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file, const char *path, int flags) {
         return err;
     }
     LFS_TRACE("lfs_file_open(%p, %p, \"%s\", %x)",
-            (void*)lfs, (void*)file, path, flags);
+            (void*)lfs, (void*)file, path, (unsigned)flags);
     LFS_ASSERT(!lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
 
     err = lfs_file_open_(lfs, file, path, flags);
@@ -6071,7 +6133,7 @@ int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
     }
     LFS_TRACE("lfs_file_opencfg(%p, %p, \"%s\", %x, %p {"
                  ".buffer=%p, .attrs=%p, .attr_count=%"PRIu32"})",
-            (void*)lfs, (void*)file, path, flags,
+            (void*)lfs, (void*)file, path, (unsigned)flags,
             (void*)cfg, cfg->buffer, (void*)cfg->attrs, cfg->attr_count);
     LFS_ASSERT(!lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
 
@@ -6224,7 +6286,7 @@ lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
 
     lfs_soff_t res = lfs_file_size_(lfs, file);
 
-    LFS_TRACE("lfs_file_size -> %"PRId32, res);
+    LFS_TRACE("lfs_file_size -> %"PRIu32, res);
     LFS_UNLOCK(lfs->cfg);
     return res;
 }
@@ -6433,7 +6495,7 @@ int lfs_migrate(lfs_t *lfs, const struct lfs_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", "

lfs.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 LFS_VERSION 0x00020009
+#define LFS_VERSION 0x0002000a
 #define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
 #define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >>  0))
 

lfs_util.h

@@ -8,6 +8,9 @@
 #ifndef LFS_UTIL_H
 #define LFS_UTIL_H
 
+#define LFS_STRINGIZE(x) LFS_STRINGIZE2(x)
+#define LFS_STRINGIZE2(x) #x
+
 // Users can override lfs_util.h with their own configuration by defining
 // LFS_CONFIG as a header file to include (-DLFS_CONFIG=lfs_config.h).
 //
@@ -15,11 +18,26 @@
 // provided by the config file. To start, I would suggest copying lfs_util.h
 // and modifying as needed.
 #ifdef LFS_CONFIG
-#define LFS_STRINGIZE(x) LFS_STRINGIZE2(x)
-#define LFS_STRINGIZE2(x) #x
 #include LFS_STRINGIZE(LFS_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 LFS_MALLOC(sz) my_malloc(sz)
+//
+// And build littlefs with the header by defining LFS_DEFINES.
+// (-DLFS_DEFINES=my_defines.h)
+
+#ifdef LFS_DEFINES
+#include LFS_STRINGIZE(LFS_DEFINES)
+#endif
+
 // System includes
 #include <stdint.h>
 #include <stdbool.h>

runners/bench_runner.c

@@ -1322,6 +1322,7 @@ void perm_run(
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
         .compact_thresh     = COMPACT_THRESH,
+        .metadata_max       = METADATA_MAX,
         .inline_max         = INLINE_MAX,
     };
 

runners/bench_runner.h

@@ -96,12 +96,13 @@ intmax_t bench_define(size_t define);
 #define CACHE_SIZE_i         6
 #define LOOKAHEAD_SIZE_i     7
 #define COMPACT_THRESH_i     8
-#define INLINE_MAX_i         9
-#define BLOCK_CYCLES_i       10
-#define ERASE_VALUE_i        11
-#define ERASE_CYCLES_i       12
-#define BADBLOCK_BEHAVIOR_i  13
-#define POWERLOSS_BEHAVIOR_i 14
+#define METADATA_MAX_i       9
+#define INLINE_MAX_i         10
+#define BLOCK_CYCLES_i       11
+#define ERASE_VALUE_i        12
+#define ERASE_CYCLES_i       13
+#define BADBLOCK_BEHAVIOR_i  14
+#define POWERLOSS_BEHAVIOR_i 15
 
 #define READ_SIZE           bench_define(READ_SIZE_i)
 #define PROG_SIZE           bench_define(PROG_SIZE_i)
@@ -112,6 +113,7 @@ intmax_t bench_define(size_t define);
 #define CACHE_SIZE          bench_define(CACHE_SIZE_i)
 #define LOOKAHEAD_SIZE      bench_define(LOOKAHEAD_SIZE_i)
 #define COMPACT_THRESH      bench_define(COMPACT_THRESH_i)
+#define METADATA_MAX        bench_define(METADATA_MAX_i)
 #define INLINE_MAX          bench_define(INLINE_MAX_i)
 #define BLOCK_CYCLES        bench_define(BLOCK_CYCLES_i)
 #define ERASE_VALUE         bench_define(ERASE_VALUE_i)
@@ -129,6 +131,7 @@ intmax_t bench_define(size_t define);
     BENCH_DEF(CACHE_SIZE,         lfs_max(64,lfs_max(READ_SIZE,PROG_SIZE))) \
     BENCH_DEF(LOOKAHEAD_SIZE,     16) \
     BENCH_DEF(COMPACT_THRESH,     0) \
+    BENCH_DEF(METADATA_MAX,       0) \
     BENCH_DEF(INLINE_MAX,         0) \
     BENCH_DEF(BLOCK_CYCLES,       -1) \
     BENCH_DEF(ERASE_VALUE,        0xff) \
@@ -137,7 +140,7 @@ intmax_t bench_define(size_t define);
     BENCH_DEF(POWERLOSS_BEHAVIOR, LFS_EMUBD_POWERLOSS_NOOP)
 
 #define BENCH_GEOMETRY_DEFINE_COUNT 4
-#define BENCH_IMPLICIT_DEFINE_COUNT 15
+#define BENCH_IMPLICIT_DEFINE_COUNT 16
 
 
 #endif

runners/test_runner.c

@@ -1347,6 +1347,7 @@ static void run_powerloss_none(
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
         .compact_thresh     = COMPACT_THRESH,
+        .metadata_max       = METADATA_MAX,
         .inline_max         = INLINE_MAX,
     #ifdef LFS_MULTIVERSION
         .disk_version       = DISK_VERSION,
@@ -1425,6 +1426,7 @@ static void run_powerloss_linear(
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
         .compact_thresh     = COMPACT_THRESH,
+        .metadata_max       = METADATA_MAX,
         .inline_max         = INLINE_MAX,
     #ifdef LFS_MULTIVERSION
         .disk_version       = DISK_VERSION,
@@ -1520,6 +1522,7 @@ static void run_powerloss_log(
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
         .compact_thresh     = COMPACT_THRESH,
+        .metadata_max       = METADATA_MAX,
         .inline_max         = INLINE_MAX,
     #ifdef LFS_MULTIVERSION
         .disk_version       = DISK_VERSION,
@@ -1613,6 +1616,7 @@ static void run_powerloss_cycles(
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
         .compact_thresh     = COMPACT_THRESH,
+        .metadata_max       = METADATA_MAX,
         .inline_max         = INLINE_MAX,
     #ifdef LFS_MULTIVERSION
         .disk_version       = DISK_VERSION,
@@ -1804,6 +1808,7 @@ static void run_powerloss_exhaustive(
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
         .compact_thresh     = COMPACT_THRESH,
+        .metadata_max       = METADATA_MAX,
         .inline_max         = INLINE_MAX,
     #ifdef LFS_MULTIVERSION
         .disk_version       = DISK_VERSION,

runners/test_runner.h

@@ -89,13 +89,14 @@ intmax_t test_define(size_t define);
 #define CACHE_SIZE_i         6
 #define LOOKAHEAD_SIZE_i     7
 #define COMPACT_THRESH_i     8
-#define INLINE_MAX_i         9
-#define BLOCK_CYCLES_i       10
-#define ERASE_VALUE_i        11
-#define ERASE_CYCLES_i       12
-#define BADBLOCK_BEHAVIOR_i  13
-#define POWERLOSS_BEHAVIOR_i 14
-#define DISK_VERSION_i       15
+#define METADATA_MAX_i       9
+#define INLINE_MAX_i         10
+#define BLOCK_CYCLES_i       11
+#define ERASE_VALUE_i        12
+#define ERASE_CYCLES_i       13
+#define BADBLOCK_BEHAVIOR_i  14
+#define POWERLOSS_BEHAVIOR_i 15
+#define DISK_VERSION_i       16
 
 #define READ_SIZE           TEST_DEFINE(READ_SIZE_i)
 #define PROG_SIZE           TEST_DEFINE(PROG_SIZE_i)
@@ -106,6 +107,7 @@ intmax_t test_define(size_t define);
 #define CACHE_SIZE          TEST_DEFINE(CACHE_SIZE_i)
 #define LOOKAHEAD_SIZE      TEST_DEFINE(LOOKAHEAD_SIZE_i)
 #define COMPACT_THRESH      TEST_DEFINE(COMPACT_THRESH_i)
+#define METADATA_MAX        TEST_DEFINE(METADATA_MAX_i)
 #define INLINE_MAX          TEST_DEFINE(INLINE_MAX_i)
 #define BLOCK_CYCLES        TEST_DEFINE(BLOCK_CYCLES_i)
 #define ERASE_VALUE         TEST_DEFINE(ERASE_VALUE_i)
@@ -124,6 +126,7 @@ intmax_t test_define(size_t define);
     TEST_DEF(CACHE_SIZE,         lfs_max(64,lfs_max(READ_SIZE,PROG_SIZE))) \
     TEST_DEF(LOOKAHEAD_SIZE,     16) \
     TEST_DEF(COMPACT_THRESH,     0) \
+    TEST_DEF(METADATA_MAX,       0) \
     TEST_DEF(INLINE_MAX,         0) \
     TEST_DEF(BLOCK_CYCLES,       -1) \
     TEST_DEF(ERASE_VALUE,        0xff) \
@@ -133,7 +136,7 @@ intmax_t test_define(size_t define);
     TEST_DEF(DISK_VERSION,       0)
 
 #define TEST_GEOMETRY_DEFINE_COUNT 4
-#define TEST_IMPLICIT_DEFINE_COUNT 16
+#define TEST_IMPLICIT_DEFINE_COUNT 17
 
 
 #endif

scripts/prettyasserts.py

@@ -35,10 +35,10 @@ LEXEMES = {
     'assert':   ['assert'],
     'arrow':    ['=>'],
     'string':   [r'"(?:\\.|[^"])*"', r"'(?:\\.|[^'])\'"],
-    'paren':    ['\(', '\)'],
+    'paren':    [r'\(', r'\)'],
     'cmp':      CMP.keys(),
-    'logic':    ['\&\&', '\|\|'],
-    'sep':      [':', ';', '\{', '\}', ','],
+    'logic':    [r'\&\&', r'\|\|'],
+    'sep':      [':', ';', r'\{', r'\}', ','],
     'op':       ['->'], # specifically ops that conflict with cmp
 }
 
@@ -86,6 +86,13 @@ def write_header(f, limit=LIMIT):
     f.writeln("}")
     f.writeln()
     f.writeln("__attribute__((unused))")
+    f.writeln("static void __pretty_assert_print_ptr(")
+    f.writeln("        const void *v, size_t size) {")
+    f.writeln("    (void)size;")
+    f.writeln("    printf(\"%p\", v);")
+    f.writeln("}")
+    f.writeln()
+    f.writeln("__attribute__((unused))")
     f.writeln("static void __pretty_assert_print_mem(")
     f.writeln("        const void *v, size_t size) {")
     f.writeln("    const uint8_t *v_ = v;")
@@ -183,6 +190,23 @@ def write_header(f, limit=LIMIT):
         f.writeln("                _rh, strlen(_rh)); \\")
         f.writeln("    } \\")
         f.writeln("} while (0)")
+    for op, cmp in sorted(CMP.items()):
+        # Only EQ and NE are supported when compared to NULL.
+        if cmp not in ['eq', 'ne']:
+            continue
+        f.writeln("#define __PRETTY_ASSERT_PTR_%s(lh, rh) do { \\"
+            % cmp.upper())
+        f.writeln("    const void *_lh = (const void*)(uintptr_t)lh; \\")
+        f.writeln("    const void *_rh = (const void*)(uintptr_t)rh; \\")
+        f.writeln("    if (!(_lh %s _rh)) { \\" % op)
+        f.writeln("        __pretty_assert_fail( \\")
+        f.writeln("                __FILE__, __LINE__, \\")
+        f.writeln("                __pretty_assert_print_ptr, \"%s\", \\"
+            % cmp)
+        f.writeln("                (const void*){_lh}, 0, \\")
+        f.writeln("                (const void*){_rh}, 0); \\")
+        f.writeln("    } \\")
+        f.writeln("} while (0)")
     f.writeln()
     f.writeln()
 
@@ -301,6 +325,8 @@ def p_assert(p):
         cmp = p.expect('cmp') ; p.accept('ws')
         rh = p_expr(p) ; p.accept('ws')
         p.expect(')')
+        if rh == 'NULL' or lh == 'NULL':
+            return mkassert('ptr', CMP[cmp], lh, rh)
         return mkassert('int', CMP[cmp], lh, rh)
     except ParseFailure:
         p.pop(state)

scripts/test.py

@@ -102,9 +102,9 @@ class TestCase:
                 # the runner itself.
                 for v_ in csplit(v):
                     m = re.search(r'\brange\b\s*\('
-                        '(?P<start>[^,\s]*)'
-                        '\s*(?:,\s*(?P<stop>[^,\s]*)'
-                        '\s*(?:,\s*(?P<step>[^,\s]*)\s*)?)?\)',
+                        r'(?P<start>[^,\s]*)'
+                        r'\s*(?:,\s*(?P<stop>[^,\s]*)'
+                        r'\s*(?:,\s*(?P<step>[^,\s]*)\s*)?)?\)',
                         v_)
                     if m:
                         start = (int(m.group('start'), 0)
@@ -163,8 +163,8 @@ class TestSuite:
             code_linenos = []
             for i, line in enumerate(f):
                 match = re.match(
-                    '(?P<case>\[\s*cases\s*\.\s*(?P<name>\w+)\s*\])'
-                        '|' '(?P<code>code\s*=)',
+                    r'(?P<case>\[\s*cases\s*\.\s*(?P<name>\w+)\s*\])'
+                        r'|' r'(?P<code>code\s*=)',
                     line)
                 if match and match.group('case'):
                     case_linenos.append((i+1, match.group('name')))
@@ -602,9 +602,9 @@ def find_perms(runner_, ids=[], **args):
         errors='replace',
         close_fds=False)
     pattern = re.compile(
-        '^(?P<case>[^\s]+)'
-            '\s+(?P<flags>[^\s]+)'
-            '\s+(?P<filtered>\d+)/(?P<perms>\d+)')
+        r'^(?P<case>[^\s]+)'
+            r'\s+(?P<flags>[^\s]+)'
+            r'\s+(?P<filtered>\d+)/(?P<perms>\d+)')
     # skip the first line
     for line in it.islice(proc.stdout, 1, None):
         m = pattern.match(line)
@@ -632,8 +632,8 @@ def find_perms(runner_, ids=[], **args):
         errors='replace',
         close_fds=False)
     pattern = re.compile(
-        '^(?P<case>[^\s]+)'
-            '\s+(?P<path>[^:]+):(?P<lineno>\d+)')
+        r'^(?P<case>[^\s]+)'
+            r'\s+(?P<path>[^:]+):(?P<lineno>\d+)')
     # skip the first line
     for line in it.islice(proc.stdout, 1, None):
         m = pattern.match(line)
@@ -676,8 +676,8 @@ def find_path(runner_, id, **args):
         errors='replace',
         close_fds=False)
     pattern = re.compile(
-        '^(?P<case>[^\s]+)'
-            '\s+(?P<path>[^:]+):(?P<lineno>\d+)')
+        r'^(?P<case>[^\s]+)'
+            r'\s+(?P<path>[^:]+):(?P<lineno>\d+)')
     # skip the first line
     for line in it.islice(proc.stdout, 1, None):
         m = pattern.match(line)
@@ -706,7 +706,7 @@ def find_defines(runner_, id, **args):
         errors='replace',
         close_fds=False)
     defines = co.OrderedDict()
-    pattern = re.compile('^(?P<define>\w+)=(?P<value>.+)')
+    pattern = re.compile(r'^(?P<define>\w+)=(?P<value>.+)')
     for line in proc.stdout:
         m = pattern.match(line)
         if m:
@@ -781,12 +781,12 @@ def run_stage(name, runner_, ids, stdout_, trace_, output_, **args):
     failures = []
     killed = False
 
-    pattern = re.compile('^(?:'
-            '(?P<op>running|finished|skipped|powerloss) '
-                '(?P<id>(?P<case>[^:]+)[^\s]*)'
-            '|' '(?P<path>[^:]+):(?P<lineno>\d+):(?P<op_>assert):'
-                ' *(?P<message>.*)'
-        ')$')
+    pattern = re.compile(r'^(?:'
+            r'(?P<op>running|finished|skipped|powerloss) '
+                r'(?P<id>(?P<case>[^:]+)[^\s]*)'
+            r'|' r'(?P<path>[^:]+):(?P<lineno>\d+):(?P<op_>assert):'
+                r' *(?P<message>.*)'
+        r')$')
     locals = th.local()
     children = set()
 

tests/test_dirs.toml

@@ -725,6 +725,82 @@ code = '''
     lfs_unmount(&lfs) => 0;
 '''
 
+[cases.test_dirs_remove_read]
+defines.N = 10
+if = 'N < BLOCK_COUNT/2'
+code = '''
+    lfs_t lfs;
+    lfs_format(&lfs, cfg) => 0;
+    lfs_mount(&lfs, cfg) => 0;
+    lfs_mkdir(&lfs, "prickly-pear") => 0;
+    for (int i = 0; i < N; i++) {
+        char path[1024];
+        sprintf(path, "prickly-pear/cactus%03d", i);
+        lfs_mkdir(&lfs, path) => 0;
+    }
+    lfs_dir_t dir;
+    lfs_dir_open(&lfs, &dir, "prickly-pear") => 0;
+    struct lfs_info info;
+    lfs_dir_read(&lfs, &dir, &info) => 1;
+    assert(info.type == LFS_TYPE_DIR);
+    assert(strcmp(info.name, ".") == 0);
+    lfs_dir_read(&lfs, &dir, &info) => 1;
+    assert(info.type == LFS_TYPE_DIR);
+    assert(strcmp(info.name, "..") == 0);
+    for (int i = 0; i < N; i++) {
+        char path[1024];
+        sprintf(path, "cactus%03d", i);
+        lfs_dir_read(&lfs, &dir, &info) => 1;
+        assert(info.type == LFS_TYPE_DIR);
+        assert(strcmp(info.name, path) == 0);
+    }
+    lfs_dir_read(&lfs, &dir, &info) => 0;
+    lfs_dir_close(&lfs, &dir) => 0;
+    lfs_unmount(&lfs);
+
+    for (lfs_size_t k = 0; k < N; k++) {
+        for (lfs_size_t j = 0; j < N; j++) {
+            lfs_mount(&lfs, cfg) => 0;
+            lfs_dir_open(&lfs, &dir, "prickly-pear") => 0;
+            lfs_dir_read(&lfs, &dir, &info) => 1;
+            assert(info.type == LFS_TYPE_DIR);
+            assert(strcmp(info.name, ".") == 0);
+            lfs_dir_read(&lfs, &dir, &info) => 1;
+            assert(info.type == LFS_TYPE_DIR);
+            assert(strcmp(info.name, "..") == 0);
+            // iterate over dirs < j
+            for (unsigned i = 0; i < j; i++) {
+                char path[1024];
+                sprintf(path, "cactus%03d", i);
+                lfs_dir_read(&lfs, &dir, &info) => 1;
+                assert(info.type == LFS_TYPE_DIR);
+                assert(strcmp(info.name, path) == 0);
+            }
+
+            // remove k while iterating
+            char path[1024];
+            sprintf(path, "prickly-pear/cactus%03d", k);
+            lfs_remove(&lfs, path) => 0;
+
+            // iterate over dirs >= j
+            for (unsigned i = j; i < ((k >= j) ? N-1 : N); i++) {
+                char path[1024];
+                sprintf(path, "cactus%03d", (k >= j && i >= k) ? i+1 : i);
+                lfs_dir_read(&lfs, &dir, &info) => 1;
+                assert(info.type == LFS_TYPE_DIR);
+                assert(strcmp(info.name, path) == 0);
+            }
+            lfs_dir_read(&lfs, &dir, &info) => 0;
+            lfs_dir_close(&lfs, &dir) => 0;
+
+            // recreate k
+            sprintf(path, "prickly-pear/cactus%03d", k);
+            lfs_mkdir(&lfs, path) => 0;
+            lfs_unmount(&lfs) => 0;
+        }
+    }
+'''
+
 [cases.test_dirs_other_errors]
 code = '''
     lfs_t lfs;

tests/test_seek.toml

@@ -137,6 +137,130 @@ code = '''
     lfs_unmount(&lfs) => 0;
 '''
 
+# boundary seek and reads
+[cases.test_seek_boundary_read]
+defines.COUNT = 132
+code = '''
+    lfs_t lfs;
+    lfs_format(&lfs, cfg) => 0;
+    lfs_mount(&lfs, cfg) => 0;
+    lfs_file_t file;
+    lfs_file_open(&lfs, &file, "kitty",
+            LFS_O_WRONLY | LFS_O_CREAT | LFS_O_APPEND) => 0;
+    size_t size = strlen("kittycatcat");
+    uint8_t buffer[1024];
+    memcpy(buffer, "kittycatcat", size);
+    for (int j = 0; j < COUNT; j++) {
+        lfs_file_write(&lfs, &file, buffer, size);
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    lfs_mount(&lfs, cfg) => 0;
+    lfs_file_open(&lfs, &file, "kitty", LFS_O_RDONLY) => 0;
+
+    size = strlen("kittycatcat");
+    const lfs_soff_t offsets[] = {
+        512,
+        1024-4,
+        512+1,
+        1024-4+1,
+        512-1,
+        1024-4-1,
+
+        512-strlen("kittycatcat"),
+        1024-4-strlen("kittycatcat"),
+        512-strlen("kittycatcat")+1,
+        1024-4-strlen("kittycatcat")+1,
+        512-strlen("kittycatcat")-1,
+        1024-4-strlen("kittycatcat")-1,
+
+        strlen("kittycatcat")*(COUNT-2)-1,
+    };
+
+    for (unsigned i = 0; i < sizeof(offsets) / sizeof(offsets[0]); i++) {
+        lfs_soff_t off = offsets[i];
+        // read @ offset
+        lfs_file_seek(&lfs, &file, off, LFS_SEEK_SET) => off;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[off % strlen("kittycatcat")],
+                size) => 0;
+        // read after
+        lfs_file_seek(&lfs, &file, off+strlen("kittycatcat")+1, LFS_SEEK_SET)
+                => off+strlen("kittycatcat")+1;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[(off+1) % strlen("kittycatcat")],
+                size) => 0;
+        // read before
+        lfs_file_seek(&lfs, &file, off-strlen("kittycatcat")-1, LFS_SEEK_SET)
+                => off-strlen("kittycatcat")-1;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[(off-1) % strlen("kittycatcat")],
+                size) => 0;
+
+        // read @ 0
+        lfs_file_seek(&lfs, &file, 0, LFS_SEEK_SET) => 0;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer, "kittycatcat", size) => 0;
+
+        // read @ offset
+        lfs_file_seek(&lfs, &file, off, LFS_SEEK_SET) => off;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[off % strlen("kittycatcat")],
+                size) => 0;
+        // read after
+        lfs_file_seek(&lfs, &file, off+strlen("kittycatcat")+1, LFS_SEEK_SET)
+                => off+strlen("kittycatcat")+1;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[(off+1) % strlen("kittycatcat")],
+                size) => 0;
+        // read before
+        lfs_file_seek(&lfs, &file, off-strlen("kittycatcat")-1, LFS_SEEK_SET)
+                => off-strlen("kittycatcat")-1;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[(off-1) % strlen("kittycatcat")],
+                size) => 0;
+
+        // sync
+        lfs_file_sync(&lfs, &file) => 0;
+
+        // read @ 0
+        lfs_file_seek(&lfs, &file, 0, LFS_SEEK_SET) => 0;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer, "kittycatcat", size) => 0;
+
+        // read @ offset
+        lfs_file_seek(&lfs, &file, off, LFS_SEEK_SET) => off;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[off % strlen("kittycatcat")],
+                size) => 0;
+        // read after
+        lfs_file_seek(&lfs, &file, off+strlen("kittycatcat")+1, LFS_SEEK_SET)
+                => off+strlen("kittycatcat")+1;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[(off+1) % strlen("kittycatcat")],
+                size) => 0;
+        // read before
+        lfs_file_seek(&lfs, &file, off-strlen("kittycatcat")-1, LFS_SEEK_SET)
+                => off-strlen("kittycatcat")-1;
+        lfs_file_read(&lfs, &file, buffer, size) => size;
+        memcmp(buffer,
+                &"kittycatcatkittycatcat"[(off-1) % strlen("kittycatcat")],
+                size) => 0;
+    }
+
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+'''
+
 # boundary seek and writes
 [cases.test_seek_boundary_write]
 defines.COUNT = 132
@@ -160,31 +284,54 @@ code = '''
     lfs_file_open(&lfs, &file, "kitty", LFS_O_RDWR) => 0;
 
     size = strlen("hedgehoghog");
-    const lfs_soff_t offsets[] = {512, 1020, 513, 1021, 511, 1019, 1441};
+    const lfs_soff_t offsets[] = {
+        512,
+        1024-4,
+        512+1,
+        1024-4+1,
+        512-1,
+        1024-4-1,
+
+        512-strlen("kittycatcat"),
+        1024-4-strlen("kittycatcat"),
+        512-strlen("kittycatcat")+1,
+        1024-4-strlen("kittycatcat")+1,
+        512-strlen("kittycatcat")-1,
+        1024-4-strlen("kittycatcat")-1,
+
+        strlen("kittycatcat")*(COUNT-2)-1,
+    };
 
     for (unsigned i = 0; i < sizeof(offsets) / sizeof(offsets[0]); i++) {
         lfs_soff_t off = offsets[i];
+        // write @ offset
         memcpy(buffer, "hedgehoghog", size);
         lfs_file_seek(&lfs, &file, off, LFS_SEEK_SET) => off;
         lfs_file_write(&lfs, &file, buffer, size) => size;
+
+        // read @ offset
         lfs_file_seek(&lfs, &file, off, LFS_SEEK_SET) => off;
         lfs_file_read(&lfs, &file, buffer, size) => size;
         memcmp(buffer, "hedgehoghog", size) => 0;
 
+        // read @ 0
         lfs_file_seek(&lfs, &file, 0, LFS_SEEK_SET) => 0;
         lfs_file_read(&lfs, &file, buffer, size) => size;
         memcmp(buffer, "kittycatcat", size) => 0;
 
+        // read @ offset
         lfs_file_seek(&lfs, &file, off, LFS_SEEK_SET) => off;
         lfs_file_read(&lfs, &file, buffer, size) => size;
         memcmp(buffer, "hedgehoghog", size) => 0;
 
         lfs_file_sync(&lfs, &file) => 0;
 
+        // read @ 0
         lfs_file_seek(&lfs, &file, 0, LFS_SEEK_SET) => 0;
         lfs_file_read(&lfs, &file, buffer, size) => size;
         memcmp(buffer, "kittycatcat", size) => 0;
 
+        // read @ offset
         lfs_file_seek(&lfs, &file, off, LFS_SEEK_SET) => off;
         lfs_file_read(&lfs, &file, buffer, size) => size;
         memcmp(buffer, "hedgehoghog", size) => 0;

tests/test_superblocks.toml

@@ -523,3 +523,30 @@ code = '''
     assert(memcmp(buffer, "hello!", 6) == 0);
     lfs_unmount(&lfs) => 0;
 '''
+
+# test that metadata_max does not cause problems for superblock compaction
+[cases.test_superblocks_metadata_max]
+defines.METADATA_MAX = [
+    'lfs_max(512, PROG_SIZE)',
+    'lfs_max(BLOCK_SIZE/2, PROG_SIZE)',
+    'BLOCK_SIZE'
+]
+defines.N = [10, 100, 1000]
+code = '''
+    lfs_t lfs;
+    lfs_format(&lfs, cfg) => 0;
+    lfs_mount(&lfs, cfg) => 0;
+    for (int i = 0; i < N; i++) {
+        lfs_file_t file;
+        char name[256];
+        sprintf(name, "hello%03x", i);
+        lfs_file_open(&lfs, &file, name,
+                LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
+        lfs_file_close(&lfs, &file) => 0;
+        struct lfs_info info;
+        lfs_stat(&lfs, name, &info) => 0;
+        assert(strcmp(info.name, name) == 0);
+        assert(info.type == LFS_TYPE_REG);
+    }
+    lfs_unmount(&lfs) => 0;
+'''