Merge branch 'master' into test-revamp

Indicate C99 standard as target for LittleFS code

.gitignore

@@ -8,3 +8,5 @@ blocks/
 lfs
 test.c
 tests/*.toml.*
+scripts/__pycache__
+.gdb_history

README.md

@@ -115,6 +115,9 @@ the filesystem until sync or close is called on the file.
 
 ## Other notes
 
+Littlefs is written in C, and specifically should compile with any compiler
+that conforms to the `C99` standard.
+
 All littlefs calls have the potential to return a negative error code. The
 errors can be either one of those found in the `enum lfs_error` in
 [lfs.h](lfs.h), or an error returned by the user's block device operations.

SPEC.md

@@ -289,8 +289,8 @@ Layout of the name tag:
 ```
         tag                          data
 [--      32      --][---        variable length        ---]
-[1| 3| 8 | 10 | 10 ][---            (size)             ---]
- ^  ^  ^    ^    ^- size               ^- file name
+[1| 3| 8 | 10 | 10 ][---          (size * 8)           ---]
+ ^  ^  ^    ^    ^- size                   ^- file name
  |  |  |    '------ id
  |  |  '----------- file type
  |  '-------------- type1 (0x0)
@@ -470,8 +470,8 @@ Layout of the inline-struct tag:
 ```
         tag                          data
 [--      32      --][---        variable length        ---]
-[1|- 11 -| 10 | 10 ][---            (size)             ---]
- ^    ^     ^    ^- size               ^- inline data
+[1|- 11 -| 10 | 10 ][---           (size * 8)          ---]
+ ^    ^     ^    ^- size                    ^- inline data
  |    |     '------ id
  |    '------------ type (0x201)
  '----------------- valid bit
@@ -556,8 +556,8 @@ Layout of the user-attr tag:
 ```
         tag                          data
 [--      32      --][---        variable length        ---]
-[1| 3| 8 | 10 | 10 ][---            (size)             ---]
- ^  ^  ^    ^    ^- size               ^- attr data
+[1| 3| 8 | 10 | 10 ][---           (size * 8)          ---]
+ ^  ^  ^    ^    ^- size                    ^- attr data
  |  |  |    '------ id
  |  |  '----------- attr type
  |  '-------------- type1 (0x3)
@@ -764,9 +764,9 @@ Layout of the CRC tag:
 ```
         tag                                    data
 [--      32      --][--      32      --|---        variable length        ---]
-[1| 3| 8 | 10 | 10 ][--      32      --|---            (size)             ---]
- ^  ^  ^    ^    ^            ^- crc                      ^- padding
- |  |  |    |    '- size (12)
+[1| 3| 8 | 10 | 10 ][--      32      --|---        (size * 8 - 32)        ---]
+ ^  ^  ^    ^    ^            ^- crc                             ^- padding
+ |  |  |    |    '- size
  |  |  |    '------ id (0x3ff)
  |  |  '----------- valid state
  |  '-------------- type1 (0x5)

bd/lfs_filebd.c

@@ -12,7 +12,7 @@
 
 int lfs_filebd_createcfg(const struct lfs_config *cfg, const char *path,
         const struct lfs_filebd_config *bdcfg) {
-    LFS_TRACE("lfs_filebd_createcfg(%p {.context=%p, "
+    LFS_FILEBD_TRACE("lfs_filebd_createcfg(%p {.context=%p, "
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
@@ -30,16 +30,16 @@ int lfs_filebd_createcfg(const struct lfs_config *cfg, const char *path,
     bd->fd = open(path, O_RDWR | O_CREAT, 0666);
     if (bd->fd < 0) {
         int err = -errno;
-        LFS_TRACE("lfs_filebd_createcfg -> %d", err);
+        LFS_FILEBD_TRACE("lfs_filebd_createcfg -> %d", err);
         return err;
     }
 
-    LFS_TRACE("lfs_filebd_createcfg -> %d", 0);
+    LFS_FILEBD_TRACE("lfs_filebd_createcfg -> %d", 0);
     return 0;
 }
 
 int lfs_filebd_create(const struct lfs_config *cfg, const char *path) {
-    LFS_TRACE("lfs_filebd_create(%p {.context=%p, "
+    LFS_FILEBD_TRACE("lfs_filebd_create(%p {.context=%p, "
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
@@ -51,26 +51,27 @@ int lfs_filebd_create(const struct lfs_config *cfg, const char *path) {
             path);
     static const struct lfs_filebd_config defaults = {.erase_value=-1};
     int err = lfs_filebd_createcfg(cfg, path, &defaults);
-    LFS_TRACE("lfs_filebd_create -> %d", err);
+    LFS_FILEBD_TRACE("lfs_filebd_create -> %d", err);
     return err;
 }
 
 int lfs_filebd_destroy(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_filebd_destroy(%p)", (void*)cfg);
+    LFS_FILEBD_TRACE("lfs_filebd_destroy(%p)", (void*)cfg);
     lfs_filebd_t *bd = cfg->context;
     int err = close(bd->fd);
     if (err < 0) {
         err = -errno;
-        LFS_TRACE("lfs_filebd_destroy -> %d", err);
+        LFS_FILEBD_TRACE("lfs_filebd_destroy -> %d", err);
         return err;
     }
-    LFS_TRACE("lfs_filebd_destroy -> %d", 0);
+    LFS_FILEBD_TRACE("lfs_filebd_destroy -> %d", 0);
     return 0;
 }
 
 int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_filebd_read(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+    LFS_FILEBD_TRACE("lfs_filebd_read(%p, "
+                "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
             (void*)cfg, block, off, buffer, size);
     lfs_filebd_t *bd = cfg->context;
 
@@ -89,24 +90,24 @@ int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
             (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
     if (res1 < 0) {
         int err = -errno;
-        LFS_TRACE("lfs_filebd_read -> %d", err);
+        LFS_FILEBD_TRACE("lfs_filebd_read -> %d", err);
         return err;
     }
 
     ssize_t res2 = read(bd->fd, buffer, size);
     if (res2 < 0) {
         int err = -errno;
-        LFS_TRACE("lfs_filebd_read -> %d", err);
+        LFS_FILEBD_TRACE("lfs_filebd_read -> %d", err);
         return err;
     }
 
-    LFS_TRACE("lfs_filebd_read -> %d", 0);
+    LFS_FILEBD_TRACE("lfs_filebd_read -> %d", 0);
     return 0;
 }
 
 int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, const void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_filebd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+    LFS_FILEBD_TRACE("lfs_filebd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
             (void*)cfg, block, off, buffer, size);
     lfs_filebd_t *bd = cfg->context;
 
@@ -121,7 +122,7 @@ int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
                 (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
         if (res1 < 0) {
             int err = -errno;
-            LFS_TRACE("lfs_filebd_prog -> %d", err);
+            LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
             return err;
         }
 
@@ -130,7 +131,7 @@ int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
             ssize_t res2 = read(bd->fd, &c, 1);
             if (res2 < 0) {
                 int err = -errno;
-                LFS_TRACE("lfs_filebd_prog -> %d", err);
+                LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
                 return err;
             }
 
@@ -143,23 +144,23 @@ int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
             (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
     if (res1 < 0) {
         int err = -errno;
-        LFS_TRACE("lfs_filebd_prog -> %d", err);
+        LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
         return err;
     }
 
     ssize_t res2 = write(bd->fd, buffer, size);
     if (res2 < 0) {
         int err = -errno;
-        LFS_TRACE("lfs_filebd_prog -> %d", err);
+        LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
         return err;
     }
 
-    LFS_TRACE("lfs_filebd_prog -> %d", 0);
+    LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", 0);
     return 0;
 }
 
 int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block) {
-    LFS_TRACE("lfs_filebd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
+    LFS_FILEBD_TRACE("lfs_filebd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
     lfs_filebd_t *bd = cfg->context;
 
     // check if erase is valid
@@ -170,7 +171,7 @@ int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block) {
         off_t res1 = lseek(bd->fd, (off_t)block*cfg->block_size, SEEK_SET);
         if (res1 < 0) {
             int err = -errno;
-            LFS_TRACE("lfs_filebd_erase -> %d", err);
+            LFS_FILEBD_TRACE("lfs_filebd_erase -> %d", err);
             return err;
         }
 
@@ -178,27 +179,27 @@ int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block) {
             ssize_t res2 = write(bd->fd, &(uint8_t){bd->cfg->erase_value}, 1);
             if (res2 < 0) {
                 int err = -errno;
-                LFS_TRACE("lfs_filebd_erase -> %d", err);
+                LFS_FILEBD_TRACE("lfs_filebd_erase -> %d", err);
                 return err;
             }
         }
     }
 
-    LFS_TRACE("lfs_filebd_erase -> %d", 0);
+    LFS_FILEBD_TRACE("lfs_filebd_erase -> %d", 0);
     return 0;
 }
 
 int lfs_filebd_sync(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_filebd_sync(%p)", (void*)cfg);
+    LFS_FILEBD_TRACE("lfs_filebd_sync(%p)", (void*)cfg);
     // file sync
     lfs_filebd_t *bd = cfg->context;
     int err = fsync(bd->fd);
     if (err) {
         err = -errno;
-        LFS_TRACE("lfs_filebd_sync -> %d", 0);
+        LFS_FILEBD_TRACE("lfs_filebd_sync -> %d", 0);
         return err;
     }
 
-    LFS_TRACE("lfs_filebd_sync -> %d", 0);
+    LFS_FILEBD_TRACE("lfs_filebd_sync -> %d", 0);
     return 0;
 }

bd/lfs_filebd.h

@@ -15,6 +15,14 @@ extern "C"
 {
 #endif
 
+
+// Block device specific tracing
+#ifdef LFS_FILEBD_YES_TRACE
+#define LFS_FILEBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
+#else
+#define LFS_FILEBD_TRACE(...)
+#endif
+
 // filebd config (optional)
 struct lfs_filebd_config {
     // 8-bit erase value to use for simulating erases. -1 does not simulate

bd/lfs_rambd.c

@@ -8,7 +8,7 @@
 
 int lfs_rambd_createcfg(const struct lfs_config *cfg,
         const struct lfs_rambd_config *bdcfg) {
-    LFS_TRACE("lfs_rambd_createcfg(%p {.context=%p, "
+    LFS_RAMBD_TRACE("lfs_rambd_createcfg(%p {.context=%p, "
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
@@ -27,7 +27,7 @@ int lfs_rambd_createcfg(const struct lfs_config *cfg,
     } else {
         bd->buffer = lfs_malloc(cfg->block_size * cfg->block_count);
         if (!bd->buffer) {
-            LFS_TRACE("lfs_rambd_createcfg -> %d", LFS_ERR_NOMEM);
+            LFS_RAMBD_TRACE("lfs_rambd_createcfg -> %d", LFS_ERR_NOMEM);
             return LFS_ERR_NOMEM;
         }
     }
@@ -38,12 +38,12 @@ int lfs_rambd_createcfg(const struct lfs_config *cfg,
                 cfg->block_size * cfg->block_count);
     }
 
-    LFS_TRACE("lfs_rambd_createcfg -> %d", 0);
+    LFS_RAMBD_TRACE("lfs_rambd_createcfg -> %d", 0);
     return 0;
 }
 
 int lfs_rambd_create(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_rambd_create(%p {.context=%p, "
+    LFS_RAMBD_TRACE("lfs_rambd_create(%p {.context=%p, "
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32"})",
@@ -53,24 +53,25 @@ int lfs_rambd_create(const struct lfs_config *cfg) {
             cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count);
     static const struct lfs_rambd_config defaults = {.erase_value=-1};
     int err = lfs_rambd_createcfg(cfg, &defaults);
-    LFS_TRACE("lfs_rambd_create -> %d", err);
+    LFS_RAMBD_TRACE("lfs_rambd_create -> %d", err);
     return err;
 }
 
 int lfs_rambd_destroy(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_rambd_destroy(%p)", (void*)cfg);
+    LFS_RAMBD_TRACE("lfs_rambd_destroy(%p)", (void*)cfg);
     // clean up memory
     lfs_rambd_t *bd = cfg->context;
     if (!bd->cfg->buffer) {
         lfs_free(bd->buffer);
     }
-    LFS_TRACE("lfs_rambd_destroy -> %d", 0);
+    LFS_RAMBD_TRACE("lfs_rambd_destroy -> %d", 0);
     return 0;
 }
 
 int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_rambd_read(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+    LFS_RAMBD_TRACE("lfs_rambd_read(%p, "
+                "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
             (void*)cfg, block, off, buffer, size);
     lfs_rambd_t *bd = cfg->context;
 
@@ -82,13 +83,14 @@ int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
     // read data
     memcpy(buffer, &bd->buffer[block*cfg->block_size + off], size);
 
-    LFS_TRACE("lfs_rambd_read -> %d", 0);
+    LFS_RAMBD_TRACE("lfs_rambd_read -> %d", 0);
     return 0;
 }
 
 int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, const void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_rambd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+    LFS_RAMBD_TRACE("lfs_rambd_prog(%p, "
+                "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
             (void*)cfg, block, off, buffer, size);
     lfs_rambd_t *bd = cfg->context;
 
@@ -108,12 +110,12 @@ int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
     // program data
     memcpy(&bd->buffer[block*cfg->block_size + off], buffer, size);
 
-    LFS_TRACE("lfs_rambd_prog -> %d", 0);
+    LFS_RAMBD_TRACE("lfs_rambd_prog -> %d", 0);
     return 0;
 }
 
 int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block) {
-    LFS_TRACE("lfs_rambd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
+    LFS_RAMBD_TRACE("lfs_rambd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
     lfs_rambd_t *bd = cfg->context;
 
     // check if erase is valid
@@ -125,14 +127,14 @@ int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block) {
                 bd->cfg->erase_value, cfg->block_size);
     }
 
-    LFS_TRACE("lfs_rambd_erase -> %d", 0);
+    LFS_RAMBD_TRACE("lfs_rambd_erase -> %d", 0);
     return 0;
 }
 
 int lfs_rambd_sync(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_rambd_sync(%p)", (void*)cfg);
+    LFS_RAMBD_TRACE("lfs_rambd_sync(%p)", (void*)cfg);
     // sync does nothing because we aren't backed by anything real
     (void)cfg;
-    LFS_TRACE("lfs_rambd_sync -> %d", 0);
+    LFS_RAMBD_TRACE("lfs_rambd_sync -> %d", 0);
     return 0;
 }

bd/lfs_rambd.h

@@ -15,6 +15,14 @@ extern "C"
 {
 #endif
 
+
+// Block device specific tracing
+#ifdef LFS_RAMBD_YES_TRACE
+#define LFS_RAMBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
+#else
+#define LFS_RAMBD_TRACE(...)
+#endif
+
 // rambd config (optional)
 struct lfs_rambd_config {
     // 8-bit erase value to simulate erasing with. -1 indicates no erase

bd/lfs_testbd.c

@@ -12,7 +12,7 @@
 
 int lfs_testbd_createcfg(const struct lfs_config *cfg, const char *path,
         const struct lfs_testbd_config *bdcfg) {
-    LFS_TRACE("lfs_testbd_createcfg(%p {.context=%p, "
+    LFS_TESTBD_TRACE("lfs_testbd_createcfg(%p {.context=%p, "
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
@@ -38,9 +38,9 @@ int lfs_testbd_createcfg(const struct lfs_config *cfg, const char *path,
         if (bd->cfg->wear_buffer) {
             bd->wear = bd->cfg->wear_buffer;
         } else {
-            bd->wear = lfs_malloc(sizeof(lfs_testbd_wear_t) * cfg->block_count);
+            bd->wear = lfs_malloc(sizeof(lfs_testbd_wear_t)*cfg->block_count);
             if (!bd->wear) {
-                LFS_TRACE("lfs_testbd_createcfg -> %d", LFS_ERR_NOMEM);
+                LFS_TESTBD_TRACE("lfs_testbd_createcfg -> %d", LFS_ERR_NOMEM);
                 return LFS_ERR_NOMEM;
             }
         }
@@ -54,7 +54,7 @@ int lfs_testbd_createcfg(const struct lfs_config *cfg, const char *path,
             .erase_value = bd->cfg->erase_value,
         };
         int err = lfs_filebd_createcfg(cfg, path, &bd->u.file.cfg);
-        LFS_TRACE("lfs_testbd_createcfg -> %d", err);
+        LFS_TESTBD_TRACE("lfs_testbd_createcfg -> %d", err);
         return err;
     } else {
         bd->u.ram.cfg = (struct lfs_rambd_config){
@@ -62,13 +62,13 @@ int lfs_testbd_createcfg(const struct lfs_config *cfg, const char *path,
             .buffer = bd->cfg->buffer,
         };
         int err = lfs_rambd_createcfg(cfg, &bd->u.ram.cfg);
-        LFS_TRACE("lfs_testbd_createcfg -> %d", err);
+        LFS_TESTBD_TRACE("lfs_testbd_createcfg -> %d", err);
         return err;
     }
 }
 
 int lfs_testbd_create(const struct lfs_config *cfg, const char *path) {
-    LFS_TRACE("lfs_testbd_create(%p {.context=%p, "
+    LFS_TESTBD_TRACE("lfs_testbd_create(%p {.context=%p, "
                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
                 ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
@@ -80,12 +80,12 @@ int lfs_testbd_create(const struct lfs_config *cfg, const char *path) {
             path);
     static const struct lfs_testbd_config defaults = {.erase_value=-1};
     int err = lfs_testbd_createcfg(cfg, path, &defaults);
-    LFS_TRACE("lfs_testbd_create -> %d", err);
+    LFS_TESTBD_TRACE("lfs_testbd_create -> %d", err);
     return err;
 }
 
 int lfs_testbd_destroy(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_testbd_destroy(%p)", (void*)cfg);
+    LFS_TESTBD_TRACE("lfs_testbd_destroy(%p)", (void*)cfg);
     lfs_testbd_t *bd = cfg->context;
     if (bd->cfg->erase_cycles && !bd->cfg->wear_buffer) {
         lfs_free(bd->wear);
@@ -93,11 +93,11 @@ int lfs_testbd_destroy(const struct lfs_config *cfg) {
 
     if (bd->persist) {
         int err = lfs_filebd_destroy(cfg);
-        LFS_TRACE("lfs_testbd_destroy -> %d", err);
+        LFS_TESTBD_TRACE("lfs_testbd_destroy -> %d", err);
         return err;
     } else {
         int err = lfs_rambd_destroy(cfg);
-        LFS_TRACE("lfs_testbd_destroy -> %d", err);
+        LFS_TESTBD_TRACE("lfs_testbd_destroy -> %d", err);
         return err;
     }
 }
@@ -145,7 +145,8 @@ static int lfs_testbd_rawsync(const struct lfs_config *cfg) {
 /// block device API ///
 int lfs_testbd_read(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_testbd_read(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+    LFS_TESTBD_TRACE("lfs_testbd_read(%p, "
+                "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
             (void*)cfg, block, off, buffer, size);
     lfs_testbd_t *bd = cfg->context;
 
@@ -157,19 +158,20 @@ int lfs_testbd_read(const struct lfs_config *cfg, lfs_block_t block,
     // block bad?
     if (bd->cfg->erase_cycles && bd->wear[block] >= bd->cfg->erase_cycles &&
             bd->cfg->badblock_behavior == LFS_TESTBD_BADBLOCK_READERROR) {
-        LFS_TRACE("lfs_testbd_read -> %d", LFS_ERR_CORRUPT);
+        LFS_TESTBD_TRACE("lfs_testbd_read -> %d", LFS_ERR_CORRUPT);
         return LFS_ERR_CORRUPT;
     }
 
     // read
     int err = lfs_testbd_rawread(cfg, block, off, buffer, size);
-    LFS_TRACE("lfs_testbd_read -> %d", err);
+    LFS_TESTBD_TRACE("lfs_testbd_read -> %d", err);
     return err;
 }
 
 int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, const void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_testbd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+    LFS_TESTBD_TRACE("lfs_testbd_prog(%p, "
+                "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
             (void*)cfg, block, off, buffer, size);
     lfs_testbd_t *bd = cfg->context;
 
@@ -182,13 +184,13 @@ int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
     if (bd->cfg->erase_cycles && bd->wear[block] >= bd->cfg->erase_cycles) {
         if (bd->cfg->badblock_behavior ==
                 LFS_TESTBD_BADBLOCK_PROGERROR) {
-            LFS_TRACE("lfs_testbd_prog -> %d", LFS_ERR_CORRUPT);
+            LFS_TESTBD_TRACE("lfs_testbd_prog -> %d", LFS_ERR_CORRUPT);
             return LFS_ERR_CORRUPT;
         } else if (bd->cfg->badblock_behavior ==
                 LFS_TESTBD_BADBLOCK_PROGNOOP ||
                 bd->cfg->badblock_behavior ==
                 LFS_TESTBD_BADBLOCK_ERASENOOP) {
-            LFS_TRACE("lfs_testbd_prog -> %d", 0);
+            LFS_TESTBD_TRACE("lfs_testbd_prog -> %d", 0);
             return 0;
         }
     }
@@ -196,7 +198,7 @@ int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
     // prog
     int err = lfs_testbd_rawprog(cfg, block, off, buffer, size);
     if (err) {
-        LFS_TRACE("lfs_testbd_prog -> %d", err);
+        LFS_TESTBD_TRACE("lfs_testbd_prog -> %d", err);
         return err;
     }
 
@@ -211,12 +213,12 @@ int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
         }
     }
 
-    LFS_TRACE("lfs_testbd_prog -> %d", 0);
+    LFS_TESTBD_TRACE("lfs_testbd_prog -> %d", 0);
     return 0;
 }
 
 int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
-    LFS_TRACE("lfs_testbd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
+    LFS_TESTBD_TRACE("lfs_testbd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
     lfs_testbd_t *bd = cfg->context;
 
     // check if erase is valid
@@ -227,11 +229,11 @@ int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
         if (bd->wear[block] >= bd->cfg->erase_cycles) {
             if (bd->cfg->badblock_behavior ==
                     LFS_TESTBD_BADBLOCK_ERASEERROR) {
-                LFS_TRACE("lfs_testbd_erase -> %d", LFS_ERR_CORRUPT);
+                LFS_TESTBD_TRACE("lfs_testbd_erase -> %d", LFS_ERR_CORRUPT);
                 return LFS_ERR_CORRUPT;
             } else if (bd->cfg->badblock_behavior ==
                     LFS_TESTBD_BADBLOCK_ERASENOOP) {
-                LFS_TRACE("lfs_testbd_erase -> %d", 0);
+                LFS_TESTBD_TRACE("lfs_testbd_erase -> %d", 0);
                 return 0;
             }
         } else {
@@ -243,7 +245,7 @@ int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
     // erase
     int err = lfs_testbd_rawerase(cfg, block);
     if (err) {
-        LFS_TRACE("lfs_testbd_erase -> %d", err);
+        LFS_TESTBD_TRACE("lfs_testbd_erase -> %d", err);
         return err;
     }
 
@@ -258,14 +260,14 @@ int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
         }
     }
 
-    LFS_TRACE("lfs_testbd_prog -> %d", 0);
+    LFS_TESTBD_TRACE("lfs_testbd_prog -> %d", 0);
     return 0;
 }
 
 int lfs_testbd_sync(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_testbd_sync(%p)", (void*)cfg);
+    LFS_TESTBD_TRACE("lfs_testbd_sync(%p)", (void*)cfg);
     int err = lfs_testbd_rawsync(cfg);
-    LFS_TRACE("lfs_testbd_sync -> %d", err);
+    LFS_TESTBD_TRACE("lfs_testbd_sync -> %d", err);
     return err;
 }
 
@@ -273,20 +275,20 @@ int lfs_testbd_sync(const struct lfs_config *cfg) {
 /// simulated wear operations ///
 lfs_testbd_swear_t lfs_testbd_getwear(const struct lfs_config *cfg,
         lfs_block_t block) {
-    LFS_TRACE("lfs_testbd_getwear(%p, %"PRIu32")", (void*)cfg, block);
+    LFS_TESTBD_TRACE("lfs_testbd_getwear(%p, %"PRIu32")", (void*)cfg, block);
     lfs_testbd_t *bd = cfg->context;
 
     // check if block is valid
     LFS_ASSERT(bd->cfg->erase_cycles);
     LFS_ASSERT(block < cfg->block_count);
 
-    LFS_TRACE("lfs_testbd_getwear -> %"PRIu32, bd->wear[block]);
+    LFS_TESTBD_TRACE("lfs_testbd_getwear -> %"PRIu32, bd->wear[block]);
     return bd->wear[block];
 }
 
 int lfs_testbd_setwear(const struct lfs_config *cfg,
         lfs_block_t block, lfs_testbd_wear_t wear) {
-    LFS_TRACE("lfs_testbd_setwear(%p, %"PRIu32")", (void*)cfg, block);
+    LFS_TESTBD_TRACE("lfs_testbd_setwear(%p, %"PRIu32")", (void*)cfg, block);
     lfs_testbd_t *bd = cfg->context;
 
     // check if block is valid
@@ -295,6 +297,6 @@ int lfs_testbd_setwear(const struct lfs_config *cfg,
 
     bd->wear[block] = wear;
 
-    LFS_TRACE("lfs_testbd_setwear -> %d", 0);
+    LFS_TESTBD_TRACE("lfs_testbd_setwear -> %d", 0);
     return 0;
 }

bd/lfs_testbd.h

@@ -19,6 +19,13 @@ extern "C"
 #endif
 
 
+// Block device specific tracing
+#ifdef LFS_TESTBD_YES_TRACE
+#define LFS_TESTBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
+#else
+#define LFS_TESTBD_TRACE(...)
+#endif
+
 // Mode determining how "bad blocks" behave during testing. This simulates
 // some real-world circumstances such as progs not sticking (prog-noop),
 // a readonly disk (erase-noop), and ECC failures (read-error).

lfs.c

@@ -29,7 +29,8 @@ static int lfs_bd_read(lfs_t *lfs,
         lfs_block_t block, lfs_off_t off,
         void *buffer, lfs_size_t size) {
     uint8_t *data = buffer;
-    if ((off+size > lfs->cfg->block_size) || (block == LFS_BLOCK_NULL)) {
+    if (block >= lfs->cfg->block_count ||
+            off+size > lfs->cfg->block_size) {
         return LFS_ERR_CORRUPT;
     }
 
@@ -70,6 +71,21 @@ static int lfs_bd_read(lfs_t *lfs,
             diff = lfs_min(diff, rcache->off-off);
         }
 
+        if (size >= hint && off % lfs->cfg->read_size == 0 &&
+                size >= lfs->cfg->read_size) {
+            // bypass cache?
+            diff = lfs_aligndown(diff, lfs->cfg->read_size);
+            int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
+            if (err) {
+                return err;
+            }
+
+            data += diff;
+            off += diff;
+            size -= diff;
+            continue;
+        }
+
         // load to cache, first condition can no longer fail
         LFS_ASSERT(block < lfs->cfg->block_count);
         rcache->block = block;
@@ -172,7 +188,7 @@ static int lfs_bd_prog(lfs_t *lfs,
         lfs_block_t block, lfs_off_t off,
         const void *buffer, lfs_size_t size) {
     const uint8_t *data = buffer;
-    LFS_ASSERT(block != LFS_BLOCK_NULL);
+    LFS_ASSERT(block == LFS_BLOCK_INLINE || block < lfs->cfg->block_count);
     LFS_ASSERT(off + size <= lfs->cfg->block_size);
 
     while (size > 0) {
@@ -436,6 +452,19 @@ static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
     return 0;
 }
 
+static void lfs_alloc_ack(lfs_t *lfs) {
+    lfs->free.ack = lfs->cfg->block_count;
+}
+
+// Invalidate the lookahead buffer. This is done during mounting and
+// failed traversals
+static void lfs_alloc_reset(lfs_t *lfs) {
+    lfs->free.off = lfs->seed % lfs->cfg->block_size;
+    lfs->free.size = 0;
+    lfs->free.i = 0;
+    lfs_alloc_ack(lfs);
+}
+
 static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
     while (true) {
         while (lfs->free.i != lfs->free.size) {
@@ -476,16 +505,12 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
         memset(lfs->free.buffer, 0, lfs->cfg->lookahead_size);
         int err = lfs_fs_traverseraw(lfs, lfs_alloc_lookahead, lfs, true);
         if (err) {
+            lfs_alloc_reset(lfs);
             return err;
         }
     }
 }
 
-static void lfs_alloc_ack(lfs_t *lfs) {
-    lfs->free.ack = lfs->cfg->block_count;
-}
-
-
 /// Metadata pair and directory operations ///
 static lfs_stag_t lfs_dir_getslice(lfs_t *lfs, const lfs_mdir_t *dir,
         lfs_tag_t gmask, lfs_tag_t gtag,
@@ -747,6 +772,12 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
     // scanning the entire directory
     lfs_stag_t besttag = -1;
 
+    // if either block address is invalid we return LFS_ERR_CORRUPT here,
+    // otherwise later writes to the pair could fail
+    if (pair[0] >= lfs->cfg->block_count || pair[1] >= lfs->cfg->block_count) {
+        return LFS_ERR_CORRUPT;
+    }
+
     // find the block with the most recent revision
     uint32_t revs[2] = {0, 0};
     int r = 0;
@@ -963,7 +994,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
         dir->rev = revs[(r+1)%2];
     }
 
-    LFS_ERROR("Corrupted dir pair at %"PRIx32" %"PRIx32,
+    LFS_ERROR("Corrupted dir pair at {0x%"PRIx32", 0x%"PRIx32"}",
             dir->pair[0], dir->pair[1]);
     return LFS_ERR_CORRUPT;
 }
@@ -1651,12 +1682,13 @@ relocate:
         relocated = true;
         lfs_cache_drop(lfs, &lfs->pcache);
         if (!tired) {
-            LFS_DEBUG("Bad block at %"PRIx32, dir->pair[1]);
+            LFS_DEBUG("Bad block at 0x%"PRIx32, dir->pair[1]);
         }
 
         // can't relocate superblock, filesystem is now frozen
         if (lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0) {
-            LFS_WARN("Superblock %"PRIx32" has become unwritable", dir->pair[1]);
+            LFS_WARN("Superblock 0x%"PRIx32" has become unwritable",
+                    dir->pair[1]);
             return LFS_ERR_NOSPC;
         }
 
@@ -1672,7 +1704,8 @@ relocate:
 
     if (relocated) {
         // update references if we relocated
-        LFS_DEBUG("Relocating %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
+        LFS_DEBUG("Relocating {0x%"PRIx32", 0x%"PRIx32"} "
+                    "-> {0x%"PRIx32", 0x%"PRIx32"}",
                 oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
         int err = lfs_fs_relocate(lfs, oldpair, dir->pair);
         if (err) {
@@ -2196,7 +2229,6 @@ static int lfs_ctz_find(lfs_t *lfs,
             return err;
         }
 
-        LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
         current -= 1 << skip;
     }
 
@@ -2216,7 +2248,6 @@ static int lfs_ctz_extend(lfs_t *lfs,
         if (err) {
             return err;
         }
-        LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);
 
         {
             err = lfs_bd_erase(lfs, nblock);
@@ -2289,8 +2320,6 @@ static int lfs_ctz_extend(lfs_t *lfs,
                         return err;
                     }
                 }
-
-                LFS_ASSERT(nhead >= 2 && nhead <= lfs->cfg->block_count);
             }
 
             *block = nblock;
@@ -2299,7 +2328,7 @@ static int lfs_ctz_extend(lfs_t *lfs,
         }
 
 relocate:
-        LFS_DEBUG("Bad block at %"PRIx32, nblock);
+        LFS_DEBUG("Bad block at 0x%"PRIx32, nblock);
 
         // just clear cache and try a new block
         lfs_cache_drop(lfs, pcache);
@@ -2603,7 +2632,7 @@ static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file) {
         return 0;
 
 relocate:
-        LFS_DEBUG("Bad block at %"PRIx32, nblock);
+        LFS_DEBUG("Bad block at 0x%"PRIx32, nblock);
 
         // just clear cache and try a new block
         lfs_cache_drop(lfs, &lfs->pcache);
@@ -2680,7 +2709,7 @@ static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
                 break;
 
 relocate:
-                LFS_DEBUG("Bad block at %"PRIx32, file->block);
+                LFS_DEBUG("Bad block at 0x%"PRIx32, file->block);
                 err = lfs_file_relocate(lfs, file);
                 if (err) {
                     return err;
@@ -3661,7 +3690,15 @@ 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 cycle = 0;
     while (!lfs_pair_isnull(dir.tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            err = LFS_ERR_CORRUPT;
+            goto cleanup;
+        }
+        cycle += 1;
+
         // fetch next block in tail list
         lfs_stag_t tag = lfs_dir_fetchmatch(lfs, &dir, dir.tail,
                 LFS_MKTAG(0x7ff, 0x3ff, 0),
@@ -3696,7 +3733,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
             uint16_t minor_version = (0xffff & (superblock.version >>  0));
             if ((major_version != LFS_DISK_VERSION_MAJOR ||
                  minor_version > LFS_DISK_VERSION_MINOR)) {
-                LFS_ERROR("Invalid version %"PRIu16".%"PRIu16,
+                LFS_ERROR("Invalid version v%"PRIu16".%"PRIu16,
                         major_version, minor_version);
                 err = LFS_ERR_INVAL;
                 goto cleanup;
@@ -3752,7 +3789,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
 
     // update littlefs with gstate
     if (!lfs_gstate_iszero(&lfs->gstate)) {
-        LFS_DEBUG("Found pending gstate %08"PRIx32" %08"PRIx32" %08"PRIx32,
+        LFS_DEBUG("Found pending gstate 0x%08"PRIx32"%08"PRIx32"%08"PRIx32,
                 lfs->gstate.tag,
                 lfs->gstate.pair[0],
                 lfs->gstate.pair[1]);
@@ -3761,10 +3798,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
     lfs->gdisk = lfs->gstate;
 
     // setup free lookahead
-    lfs->free.off = lfs->seed % lfs->cfg->block_size;
-    lfs->free.size = 0;
-    lfs->free.i = 0;
-    lfs_alloc_ack(lfs);
+    lfs_alloc_reset(lfs);
 
     LFS_TRACE("lfs_mount -> %d", 0);
     return 0;
@@ -3803,7 +3837,14 @@ int lfs_fs_traverseraw(lfs_t *lfs,
     }
 #endif
 
+    lfs_block_t cycle = 0;
     while (!lfs_pair_isnull(dir.tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            return LFS_ERR_CORRUPT;
+        }
+        cycle += 1;
+
         for (int i = 0; i < 2; i++) {
             int err = cb(data, dir.tail[i]);
             if (err) {
@@ -3887,7 +3928,14 @@ 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 cycle = 0;
     while (!lfs_pair_isnull(pdir->tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            return LFS_ERR_CORRUPT;
+        }
+        cycle += 1;
+
         if (lfs_pair_cmp(pdir->tail, pair) == 0) {
             return 0;
         }
@@ -3930,7 +3978,14 @@ 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 cycle = 0;
     while (!lfs_pair_isnull(parent->tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            return LFS_ERR_CORRUPT;
+        }
+        cycle += 1;
+
         lfs_stag_t tag = lfs_dir_fetchmatch(lfs, parent, parent->tail,
                 LFS_MKTAG(0x7ff, 0, 0x3ff),
                 LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 0, 8),
@@ -3949,8 +4004,6 @@ static int lfs_fs_relocate(lfs_t *lfs,
         const lfs_block_t oldpair[2], lfs_block_t newpair[2]) {
     // update internal root
     if (lfs_pair_cmp(oldpair, lfs->root) == 0) {
-        LFS_DEBUG("Relocating root %"PRIx32" %"PRIx32,
-                newpair[0], newpair[1]);
         lfs->root[0] = newpair[0];
         lfs->root[1] = newpair[1];
     }
@@ -3986,7 +4039,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
         if (lfs_gstate_hasmovehere(&lfs->gstate, parent.pair)) {
             moveid = lfs_tag_id(lfs->gstate.tag);
             LFS_DEBUG("Fixing move while relocating "
-                    "%"PRIx32" %"PRIx32" %"PRIx16"\n",
+                    "{0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16"\n",
                     parent.pair[0], parent.pair[1], moveid);
             lfs_fs_prepmove(lfs, 0x3ff, NULL);
             if (moveid < lfs_tag_id(tag)) {
@@ -4022,7 +4075,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
         if (lfs_gstate_hasmovehere(&lfs->gstate, parent.pair)) {
             moveid = lfs_tag_id(lfs->gstate.tag);
             LFS_DEBUG("Fixing move while relocating "
-                    "%"PRIx32" %"PRIx32" %"PRIx16"\n",
+                    "{0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16"\n",
                     parent.pair[0], parent.pair[1], moveid);
             lfs_fs_prepmove(lfs, 0x3ff, NULL);
         }
@@ -4063,7 +4116,7 @@ static int lfs_fs_demove(lfs_t *lfs) {
     }
 
     // Fix bad moves
-    LFS_DEBUG("Fixing move %"PRIx32" %"PRIx32" %"PRIx16,
+    LFS_DEBUG("Fixing move {0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16,
             lfs->gdisk.pair[0],
             lfs->gdisk.pair[1],
             lfs_tag_id(lfs->gdisk.tag));
@@ -4114,7 +4167,7 @@ static int lfs_fs_deorphan(lfs_t *lfs) {
 
             if (tag == LFS_ERR_NOENT) {
                 // we are an orphan
-                LFS_DEBUG("Fixing orphan %"PRIx32" %"PRIx32,
+                LFS_DEBUG("Fixing orphan {0x%"PRIx32", 0x%"PRIx32"}",
                         pdir.tail[0], pdir.tail[1]);
 
                 err = lfs_dir_drop(lfs, &pdir, &dir);
@@ -4136,8 +4189,8 @@ static int lfs_fs_deorphan(lfs_t *lfs) {
 
             if (!lfs_pair_sync(pair, pdir.tail)) {
                 // we have desynced
-                LFS_DEBUG("Fixing half-orphan "
-                        "%"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
+                LFS_DEBUG("Fixing half-orphan {0x%"PRIx32", 0x%"PRIx32"} "
+                            "-> {0x%"PRIx32", 0x%"PRIx32"}",
                         pdir.tail[0], pdir.tail[1], pair[0], pair[1]);
 
                 lfs_pair_tole32(pair);
@@ -4400,7 +4453,7 @@ static int lfs1_dir_fetch(lfs_t *lfs,
     }
 
     if (!valid) {
-        LFS_ERROR("Corrupted dir pair at %" PRIx32 " %" PRIx32 ,
+        LFS_ERROR("Corrupted dir pair at {0x%"PRIx32", 0x%"PRIx32"}",
                 tpair[0], tpair[1]);
         return LFS_ERR_CORRUPT;
     }
@@ -4588,7 +4641,8 @@ static int lfs1_mount(lfs_t *lfs, struct lfs1 *lfs1,
         }
 
         if (err || memcmp(superblock.d.magic, "littlefs", 8) != 0) {
-            LFS_ERROR("Invalid superblock at %d %d", 0, 1);
+            LFS_ERROR("Invalid superblock at {0x%"PRIx32", 0x%"PRIx32"}",
+                    0, 1);
             err = LFS_ERR_CORRUPT;
             goto cleanup;
         }
@@ -4597,7 +4651,7 @@ static int lfs1_mount(lfs_t *lfs, struct lfs1 *lfs1,
         uint16_t minor_version = (0xffff & (superblock.d.version >>  0));
         if ((major_version != LFS1_DISK_VERSION_MAJOR ||
              minor_version > LFS1_DISK_VERSION_MINOR)) {
-            LFS_ERROR("Invalid version %d.%d", major_version, minor_version);
+            LFS_ERROR("Invalid version v%d.%d", major_version, minor_version);
             err = LFS_ERR_INVAL;
             goto cleanup;
         }
@@ -4763,7 +4817,8 @@ int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg) {
 
             // Copy over first block to thread into fs. Unfortunately
             // if this fails there is not much we can do.
-            LFS_DEBUG("Migrating %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
+            LFS_DEBUG("Migrating {0x%"PRIx32", 0x%"PRIx32"} "
+                        "-> {0x%"PRIx32", 0x%"PRIx32"}",
                     lfs->root[0], lfs->root[1], dir1.head[0], dir1.head[1]);
 
             err = lfs_bd_erase(lfs, dir1.head[1]);

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 0x00020001
+#define LFS_VERSION 0x00020002
 #define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
 #define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >>  0))
 

lfs_util.h

@@ -50,31 +50,35 @@ extern "C"
 
 // Logging functions
 #ifdef LFS_YES_TRACE
-#define LFS_TRACE(fmt, ...) \
-    printf("%s:%d:trace: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_TRACE_(fmt, ...) \
+    printf("%s:%d:trace: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_TRACE(...) LFS_TRACE_(__VA_ARGS__, "")
 #else
-#define LFS_TRACE(fmt, ...)
+#define LFS_TRACE(...)
 #endif
 
 #ifndef LFS_NO_DEBUG
-#define LFS_DEBUG(fmt, ...) \
-    printf("%s:%d:debug: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_DEBUG_(fmt, ...) \
+    printf("%s:%d:debug: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_DEBUG(...) LFS_DEBUG_(__VA_ARGS__, "")
 #else
-#define LFS_DEBUG(fmt, ...)
+#define LFS_DEBUG(...)
 #endif
 
 #ifndef LFS_NO_WARN
-#define LFS_WARN(fmt, ...) \
-    printf("%s:%d:warn: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_WARN_(fmt, ...) \
+    printf("%s:%d:warn: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_WARN(...) LFS_WARN_(__VA_ARGS__, "")
 #else
-#define LFS_WARN(fmt, ...)
+#define LFS_WARN(...)
 #endif
 
 #ifndef LFS_NO_ERROR
-#define LFS_ERROR(fmt, ...) \
-    printf("%s:%d:error: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_ERROR_(fmt, ...) \
+    printf("%s:%d:error: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_ERROR(...) LFS_ERROR_(__VA_ARGS__, "")
 #else
-#define LFS_ERROR(fmt, ...)
+#define LFS_ERROR(...)
 #endif
 
 // Runtime assertions
@@ -107,7 +111,7 @@ static inline uint32_t lfs_alignup(uint32_t a, uint32_t alignment) {
     return lfs_aligndown(a + alignment-1, alignment);
 }
 
-// Find the next smallest power of 2 less than or equal to a
+// Find the smallest power of 2 greater than or equal to a
 static inline uint32_t lfs_npw2(uint32_t a) {
 #if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
     return 32 - __builtin_clz(a-1);

scripts/readmdir.py

@@ -233,8 +233,8 @@ class MetadataPair:
 
     def __lt__(self, other):
         # corrupt blocks don't count
-        if not self and other:
-            return True
+        if not self or not other:
+            return bool(other)
 
         # use sequence arithmetic to avoid overflow
         return not ((other.rev - self.rev) & 0x80000000)
@@ -318,14 +318,24 @@ def main(args):
 
     # find most recent pair
     mdir = MetadataPair(blocks)
-    print("mdir {%s} rev %d%s%s" % (
+
+    try:
+        mdir.tail = mdir[Tag('tail', 0, 0)]
+        if mdir.tail.size != 8 or mdir.tail.data == 8*b'\xff':
+            mdir.tail = None
+    except KeyError:
+        mdir.tail = None
+
+    print("mdir {%s} rev %d%s%s%s" % (
         ', '.join('%#x' % b
             for b in [args.block1, args.block2]
             if b is not None),
         mdir.rev,
         ' (was %s)' % ', '.join('%d' % m.rev for m in mdir.pair[1:])
         if len(mdir.pair) > 1 else '',
-        ' (corrupted)' if not mdir else ''))
+        ' (corrupted!)' if not mdir else '',
+        ' -> {%#x, %#x}' % struct.unpack('<II', mdir.tail.data)
+        if mdir.tail else ''))
     if args.all:
         mdir.dump_all(truncate=not args.no_truncate)
     elif args.log:

scripts/readtree.py

@@ -7,97 +7,14 @@ import io
 import itertools as it
 from readmdir import Tag, MetadataPair
 
-def popc(x):
-    return bin(x).count('1')
-
-def ctz(x):
-    return len(bin(x)) - len(bin(x).rstrip('0'))
-
-def dumpentries(args, mdir, f):
-    for k, id_ in enumerate(mdir.ids):
-        name = mdir[Tag('name', id_, 0)]
-        struct_ = mdir[Tag('struct', id_, 0)]
-
-        desc = "id %d %s %s" % (
-            id_, name.typerepr(),
-            json.dumps(name.data.decode('utf8')))
-        if struct_.is_('dirstruct'):
-            desc += " dir {%#x, %#x}" % struct.unpack(
-                '<II', struct_.data[:8].ljust(8, b'\xff'))
-        if struct_.is_('ctzstruct'):
-            desc += " ctz {%#x} size %d" % struct.unpack(
-                '<II', struct_.data[:8].ljust(8, b'\xff'))
-        if struct_.is_('inlinestruct'):
-            desc += " inline size %d" % struct_.size
-
-        data = None
-        if struct_.is_('inlinestruct'):
-            data = struct_.data
-        elif struct_.is_('ctzstruct'):
-            block, size = struct.unpack(
-                '<II', struct_.data[:8].ljust(8, b'\xff'))
-            data = []
-            i = 0 if size == 0 else (size-1) // (args.block_size - 8)
-            if i != 0:
-                i = ((size-1) - 4*popc(i-1)+2) // (args.block_size - 8)
-            with open(args.disk, 'rb') as f2:
-                while i >= 0:
-                    f2.seek(block * args.block_size)
-                    dat = f2.read(args.block_size)
-                    data.append(dat[4*(ctz(i)+1) if i != 0 else 0:])
-                    block, = struct.unpack('<I', dat[:4].ljust(4, b'\xff'))
-                    i -= 1
-            data = bytes(it.islice(
-                it.chain.from_iterable(reversed(data)), size))
-
-        f.write("%-45s%s\n" % (desc,
-            "%-23s  %-8s" % (
-                ' '.join('%02x' % c for c in data[:8]),
-                ''.join(c if c >= ' ' and c <= '~' else '.'
-                    for c in map(chr, data[:8])))
-            if not args.no_truncate and len(desc) < 45
-                and data is not None else ""))
-
-        if name.is_('superblock') and struct_.is_('inlinestruct'):
-            f.write(
-                "  block_size %d\n"
-                "  block_count %d\n"
-                "  name_max %d\n"
-                "  file_max %d\n"
-                "  attr_max %d\n" % struct.unpack(
-                    '<IIIII', struct_.data[4:4+20].ljust(20, b'\xff')))
-
-        for tag in mdir.tags:
-            if tag.id==id_ and tag.is_('userattr'):
-                desc = "%s size %d" % (tag.typerepr(), tag.size)
-                f.write("  %-43s%s\n" % (desc,
-                    "%-23s  %-8s" % (
-                        ' '.join('%02x' % c for c in tag.data[:8]),
-                        ''.join(c if c >= ' ' and c <= '~' else '.'
-                            for c in map(chr, tag.data[:8])))
-                    if not args.no_truncate and len(desc) < 43 else ""))
-
-                if args.no_truncate:
-                    for i in range(0, len(tag.data), 16):
-                        f.write("    %08x: %-47s  %-16s\n" % (
-                            i, ' '.join('%02x' % c for c in tag.data[i:i+16]),
-                            ''.join(c if c >= ' ' and c <= '~' else '.'
-                                for c in map(chr, tag.data[i:i+16]))))
-
-        if args.no_truncate and data is not None:
-            for i in range(0, len(data), 16):
-                f.write("  %08x: %-47s  %-16s\n" % (
-                    i, ' '.join('%02x' % c for c in data[i:i+16]),
-                    ''.join(c if c >= ' ' and c <= '~' else '.'
-                        for c in map(chr, data[i:i+16]))))
-
 def main(args):
+    superblock = None
+    gstate = b'\0\0\0\0\0\0\0\0\0\0\0\0'
+    dirs = []
+    mdirs = []
+    corrupted = []
+    cycle = False
     with open(args.disk, 'rb') as f:
-        dirs = []
-        superblock = None
-        gstate = b''
-        mdirs = []
-        cycle = False
         tail = (args.block1, args.block2)
         hard = False
         while True:
@@ -144,6 +61,10 @@ def main(args):
             except KeyError:
                 pass
 
+            # corrupted?
+            if not mdir:
+                corrupted.append(mdir)
+
             # add to directories
             mdirs.append(mdir)
             if mdir.tail is None or not mdir.tail.is_('hardtail'):
@@ -178,7 +99,7 @@ def main(args):
 
         dir[0].path = path.replace('//', '/')
 
-    # dump tree
+    # print littlefs + version info
     version = ('?', '?')
     if superblock:
         version = tuple(reversed(
@@ -187,53 +108,56 @@ def main(args):
         "data (truncated, if it fits)"
         if not any([args.no_truncate, args.tags, args.log, args.all]) else ""))
 
-    if gstate:
-        print("gstate 0x%s" % ''.join('%02x' % c for c in gstate))
-        tag = Tag(struct.unpack('<I', gstate[0:4].ljust(4, b'\xff'))[0])
-        blocks = struct.unpack('<II', gstate[4:4+8].ljust(8, b'\xff'))
-        if tag.size or not tag.isvalid:
-            print("  orphans >=%d" % max(tag.size, 1))
-        if tag.type:
-            print("  move dir {%#x, %#x} id %d" % (
-                blocks[0], blocks[1], tag.id))
+    # print gstate
+    print("gstate 0x%s" % ''.join('%02x' % c for c in gstate))
+    tag = Tag(struct.unpack('<I', gstate[0:4].ljust(4, b'\xff'))[0])
+    blocks = struct.unpack('<II', gstate[4:4+8].ljust(8, b'\xff'))
+    if tag.size or not tag.isvalid:
+        print("  orphans >=%d" % max(tag.size, 1))
+    if tag.type:
+        print("  move dir {%#x, %#x} id %d" % (
+            blocks[0], blocks[1], tag.id))
 
+    # print mdir info
     for i, dir in enumerate(dirs):
         print("dir %s" % (json.dumps(dir[0].path)
             if hasattr(dir[0], 'path') else '(orphan)'))
 
         for j, mdir in enumerate(dir):
-            print("mdir {%#x, %#x} rev %d%s" % (
-                mdir.blocks[0], mdir.blocks[1], mdir.rev,
-                ' (corrupted)' if not mdir else ''))
+            print("mdir {%#x, %#x} rev %d (was %d)%s%s" % (
+                mdir.blocks[0], mdir.blocks[1], mdir.rev, mdir.pair[1].rev,
+                ' (corrupted!)' if not mdir else '',
+                ' -> {%#x, %#x}' % struct.unpack('<II', mdir.tail.data)
+                if mdir.tail else ''))
 
             f = io.StringIO()
-            if args.tags:
-                mdir.dump_tags(f, truncate=not args.no_truncate)
-            elif args.log:
+            if args.log:
                 mdir.dump_log(f, truncate=not args.no_truncate)
             elif args.all:
                 mdir.dump_all(f, truncate=not args.no_truncate)
             else:
-                dumpentries(args, mdir, f)
+                mdir.dump_tags(f, truncate=not args.no_truncate)
 
             lines = list(filter(None, f.getvalue().split('\n')))
             for k, line in enumerate(lines):
                 print("%s %s" % (
-                    ' ' if i == len(dirs)-1 and j == len(dir)-1 else
+                    ' ' if j == len(dir)-1 else
                     'v' if k == len(lines)-1 else
-                    '.' if j == len(dir)-1 else
                     '|',
                     line))
 
-    if cycle:
-        print("*** cycle detected! -> {%#x, %#x} ***" % (cycle[0], cycle[1]))
+    errcode = 0
+    for mdir in corrupted:
+        errcode = errcode or 1
+        print("*** corrupted mdir {%#x, %#x}! ***" % (
+            mdir.blocks[0], mdir.blocks[1]))
 
     if cycle:
-        return 2
-    elif not all(mdir for dir in dirs for mdir in dir):
-        return 1
-    else:
-        return 0;
+        errcode = errcode or 2
+        print("*** cycle detected {%#x, %#x}! ***" % (
+            cycle[0], cycle[1]))
+
+    return errcode
 
 if __name__ == "__main__":
     import argparse
@@ -246,12 +170,10 @@ if __name__ == "__main__":
         help="Size of a block in bytes.")
     parser.add_argument('block1', nargs='?', default=0,
         type=lambda x: int(x, 0),
-        help="Optional first block address for finding the root.")
+        help="Optional first block address for finding the superblock.")
     parser.add_argument('block2', nargs='?', default=1,
         type=lambda x: int(x, 0),
-        help="Optional second block address for finding the root.")
-    parser.add_argument('-t', '--tags', action='store_true',
-        help="Show metadata tags instead of reconstructing entries.")
+        help="Optional second block address for finding the superblock.")
     parser.add_argument('-l', '--log', action='store_true',
         help="Show tags in log.")
     parser.add_argument('-a', '--all', action='store_true',

scripts/test.py

@@ -231,7 +231,7 @@ class TestCase:
                 ncmd.extend(['-ex', 'r'])
                 if failure.assert_:
                     ncmd.extend(['-ex', 'up 2'])
-            elif gdb == 'start':
+            elif gdb == 'main':
                 ncmd.extend([
                     '-ex', 'b %s:%d' % (self.suite.path, self.code_lineno),
                     '-ex', 'r'])
@@ -760,7 +760,7 @@ if __name__ == "__main__":
         help="Store disk image in a file.")
     parser.add_argument('-b', '--build', action='store_true',
         help="Only build the tests, do not execute.")
-    parser.add_argument('-g', '--gdb', choices=['init', 'start', 'assert'],
+    parser.add_argument('-g', '--gdb', choices=['init', 'main', 'assert'],
         nargs='?', const='assert',
         help="Drop into gdb on test failure.")
     parser.add_argument('--no-internal', action='store_true',

tests/test_alloc.toml

@@ -323,6 +323,90 @@ code = '''
     lfs_unmount(&lfs) => 0;
 '''
 
+[[case]] # what if we have a bad block during an allocation scan?
+in = "lfs.c"
+define.LFS_ERASE_CYCLES = 0xffffffff
+define.LFS_BADBLOCK_BEHAVIOR = 'LFS_TESTBD_BADBLOCK_READERROR'
+code = '''
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    // first fill to exhaustion to find available space
+    lfs_file_open(&lfs, &file, "pacman", LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    strcpy((char*)buffer, "waka");
+    size = strlen("waka");
+    lfs_size_t filesize = 0;
+    while (true) {
+        lfs_ssize_t res = lfs_file_write(&lfs, &file, buffer, size);
+        assert(res == (lfs_ssize_t)size || res == LFS_ERR_NOSPC);
+        if (res == LFS_ERR_NOSPC) {
+            break;
+        }
+        filesize += size;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    // now fill all but a couple of blocks of the filesystem with data
+    filesize -= 3*LFS_BLOCK_SIZE;
+    lfs_file_open(&lfs, &file, "pacman", LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    strcpy((char*)buffer, "waka");
+    size = strlen("waka");
+    for (lfs_size_t i = 0; i < filesize/size; i++) {
+        lfs_file_write(&lfs, &file, buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    // also save head of file so we can error during lookahead scan
+    lfs_block_t fileblock = file.ctz.head;
+    lfs_unmount(&lfs) => 0;
+
+    // remount to force an alloc scan
+    lfs_mount(&lfs, &cfg) => 0;
+
+    // but mark the head of our file as a "bad block", this is force our
+    // scan to bail early
+    lfs_testbd_setwear(&cfg, fileblock, 0xffffffff) => 0;
+    lfs_file_open(&lfs, &file, "ghost", LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    strcpy((char*)buffer, "chomp");
+    size = strlen("chomp");
+    while (true) {
+        lfs_ssize_t res = lfs_file_write(&lfs, &file, buffer, size);
+        assert(res == (lfs_ssize_t)size || res == LFS_ERR_CORRUPT);
+        if (res == LFS_ERR_CORRUPT) {
+            break;
+        }
+    }
+    lfs_file_close(&lfs, &file) => 0;
+
+    // now reverse the "bad block" and try to write the file again until we
+    // run out of space
+    lfs_testbd_setwear(&cfg, fileblock, 0) => 0;
+    lfs_file_open(&lfs, &file, "ghost", LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    strcpy((char*)buffer, "chomp");
+    size = strlen("chomp");
+    while (true) {
+        lfs_ssize_t res = lfs_file_write(&lfs, &file, buffer, size);
+        assert(res == (lfs_ssize_t)size || res == LFS_ERR_NOSPC);
+        if (res == LFS_ERR_NOSPC) {
+            break;
+        }
+    }
+    lfs_file_close(&lfs, &file) => 0;
+
+    lfs_unmount(&lfs) => 0;
+
+    // check that the disk isn't hurt
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, "pacman", LFS_O_RDONLY) => 0;
+    strcpy((char*)buffer, "waka");
+    size = strlen("waka");
+    for (lfs_size_t i = 0; i < filesize/size; i++) {
+        uint8_t rbuffer[4];
+        lfs_file_read(&lfs, &file, rbuffer, size) => size;
+        assert(memcmp(rbuffer, buffer, size) == 0);
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+'''
+
+
 # Below, I don't like these tests. They're fragile and depend _heavily_
 # on the geometry of the block device. But they are valuable. Eventually they
 # should be removed and replaced with generalized tests.

tests/test_evil.toml

@@ -0,0 +1,288 @@
+# Tests for recovering from conditions which shouldn't normally
+# happen during normal operation of littlefs
+
+# invalid pointer tests (outside of block_count)
+
+[[case]] # invalid tail-pointer test
+define.TAIL_TYPE = ['LFS_TYPE_HARDTAIL', 'LFS_TYPE_SOFTTAIL']
+define.INVALSET = [0x3, 0x1, 0x2]
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+
+    // change tail-pointer to invalid pointers
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
+                (lfs_block_t[2]){
+                    (INVALSET & 0x1) ? 0xcccccccc : 0,
+                    (INVALSET & 0x2) ? 0xcccccccc : 0}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''
+
+[[case]] # invalid dir pointer test
+define.INVALSET = [0x3, 0x1, 0x2]
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+    // make a dir
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "dir_here") => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // change the dir pointer to be invalid
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    // make sure id 1 == our directory
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("dir_here")), buffer)
+                => LFS_MKTAG(LFS_TYPE_DIR, 1, strlen("dir_here"));
+    assert(memcmp((char*)buffer, "dir_here", strlen("dir_here")) == 0);
+    // change dir pointer
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, 8),
+                (lfs_block_t[2]){
+                    (INVALSET & 0x1) ? 0xcccccccc : 0,
+                    (INVALSET & 0x2) ? 0xcccccccc : 0}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that accessing our bad dir fails, note there's a number
+    // of ways to access the dir, some can fail, but some don't
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "dir_here", &info) => 0;
+    assert(strcmp(info.name, "dir_here") == 0);
+    assert(info.type == LFS_TYPE_DIR);
+
+    lfs_dir_open(&lfs, &dir, "dir_here") => LFS_ERR_CORRUPT;
+    lfs_stat(&lfs, "dir_here/file_here", &info) => LFS_ERR_CORRUPT;
+    lfs_dir_open(&lfs, &dir, "dir_here/dir_here") => LFS_ERR_CORRUPT;
+    lfs_file_open(&lfs, &file, "dir_here/file_here",
+            LFS_O_RDONLY) => LFS_ERR_CORRUPT;
+    lfs_file_open(&lfs, &file, "dir_here/file_here",
+            LFS_O_WRONLY | LFS_O_CREAT) => LFS_ERR_CORRUPT;
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # invalid file pointer test
+in = "lfs.c"
+define.SIZE = [10, 1000, 100000] # faked file size
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+    // make a file
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, "file_here",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // change the file pointer to be invalid
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    // make sure id 1 == our file
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("file_here")), buffer)
+                => LFS_MKTAG(LFS_TYPE_REG, 1, strlen("file_here"));
+    assert(memcmp((char*)buffer, "file_here", strlen("file_here")) == 0);
+    // change file pointer
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_CTZSTRUCT, 1, sizeof(struct lfs_ctz)),
+                &(struct lfs_ctz){0xcccccccc, lfs_tole32(SIZE)}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that accessing our bad file fails, note there's a number
+    // of ways to access the dir, some can fail, but some don't
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "file_here", &info) => 0;
+    assert(strcmp(info.name, "file_here") == 0);
+    assert(info.type == LFS_TYPE_REG);
+    assert(info.size == SIZE);
+
+    lfs_file_open(&lfs, &file, "file_here", LFS_O_RDONLY) => 0;
+    lfs_file_read(&lfs, &file, buffer, SIZE) => LFS_ERR_CORRUPT;
+    lfs_file_close(&lfs, &file) => 0;
+
+    // any allocs that traverse CTZ must unfortunately must fail
+    if (SIZE > 2*LFS_BLOCK_SIZE) {
+        lfs_mkdir(&lfs, "dir_here") => LFS_ERR_CORRUPT;
+    }
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # invalid pointer in CTZ skip-list test
+define.SIZE = ['2*LFS_BLOCK_SIZE', '3*LFS_BLOCK_SIZE', '4*LFS_BLOCK_SIZE']
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+    // make a file
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, "file_here",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    for (int i = 0; i < SIZE; i++) {
+        char c = 'c';
+        lfs_file_write(&lfs, &file, &c, 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+    // change pointer in CTZ skip-list to be invalid
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    // make sure id 1 == our file and get our CTZ structure
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("file_here")), buffer)
+                => LFS_MKTAG(LFS_TYPE_REG, 1, strlen("file_here"));
+    assert(memcmp((char*)buffer, "file_here", strlen("file_here")) == 0);
+    struct lfs_ctz ctz;
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_STRUCT, 1, sizeof(struct lfs_ctz)), &ctz)
+                => LFS_MKTAG(LFS_TYPE_CTZSTRUCT, 1, sizeof(struct lfs_ctz));
+    lfs_ctz_fromle32(&ctz);
+    // rewrite block to contain bad pointer
+    uint8_t bbuffer[LFS_BLOCK_SIZE];
+    cfg.read(&cfg, ctz.head, 0, bbuffer, LFS_BLOCK_SIZE) => 0;
+    uint32_t bad = lfs_tole32(0xcccccccc);
+    memcpy(&bbuffer[0], &bad, sizeof(bad));
+    memcpy(&bbuffer[4], &bad, sizeof(bad));
+    cfg.erase(&cfg, ctz.head) => 0;
+    cfg.prog(&cfg, ctz.head, 0, bbuffer, LFS_BLOCK_SIZE) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that accessing our bad file fails, note there's a number
+    // of ways to access the dir, some can fail, but some don't
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "file_here", &info) => 0;
+    assert(strcmp(info.name, "file_here") == 0);
+    assert(info.type == LFS_TYPE_REG);
+    assert(info.size == SIZE);
+
+    lfs_file_open(&lfs, &file, "file_here", LFS_O_RDONLY) => 0;
+    lfs_file_read(&lfs, &file, buffer, SIZE) => LFS_ERR_CORRUPT;
+    lfs_file_close(&lfs, &file) => 0;
+
+    // any allocs that traverse CTZ must unfortunately must fail
+    if (SIZE > 2*LFS_BLOCK_SIZE) {
+        lfs_mkdir(&lfs, "dir_here") => LFS_ERR_CORRUPT;
+    }
+    lfs_unmount(&lfs) => 0;
+'''
+
+
+[[case]] # invalid gstate pointer
+define.INVALSET = [0x3, 0x1, 0x2]
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+
+    // create an invalid gstate
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_fs_prepmove(&lfs, 1, (lfs_block_t [2]){
+            (INVALSET & 0x1) ? 0xcccccccc : 0,
+            (INVALSET & 0x2) ? 0xcccccccc : 0});
+    lfs_dir_commit(&lfs, &mdir, NULL, 0) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    // mount may not fail, but our first alloc should fail when
+    // we try to fix the gstate
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "should_fail") => LFS_ERR_CORRUPT;
+    lfs_unmount(&lfs) => 0;
+'''
+
+# cycle detection/recovery tests
+
+[[case]] # metadata-pair threaded-list loop test
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+
+    // change tail-pointer to point to ourself
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
+                (lfs_block_t[2]){0, 1}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''
+
+[[case]] # metadata-pair threaded-list 2-length loop test
+in = "lfs.c"
+code = '''
+    // create littlefs with child dir
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "child") => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // find child
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_block_t pair[2];
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x7ff, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair)), pair)
+                => LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair));
+    lfs_pair_fromle32(pair);
+    // change tail-pointer to point to root
+    lfs_dir_fetch(&lfs, &mdir, pair) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
+                (lfs_block_t[2]){0, 1}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''
+
+[[case]] # metadata-pair threaded-list 1-length child loop test
+in = "lfs.c"
+code = '''
+    // create littlefs with child dir
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "child") => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // find child
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_block_t pair[2];
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x7ff, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair)), pair)
+                => LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair));
+    lfs_pair_fromle32(pair);
+    // change tail-pointer to point to ourself
+    lfs_dir_fetch(&lfs, &mdir, pair) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8), pair})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''