Introduced the LFS_O_SNAPSHOT flag

LFS_O_SNAPSHOT brings back some of littlefs's idiosyncratic behavior
removed in the changes to open file syncing in a form that may be more
useful for users.

LFS_O_SNAPSHOT allows you to open a "snapshot" of a file. This is a cheap,
local copy of a file who's changes are not reflected on disk.

Internally, snapshot files use the same mechanism as pending writes. A
separate, copy-on-write CTZ skip-list is created, with read-only
references to the existing data blocks until a write occurs. The
difference is that snapshot files are not enrolled in the mlist, meaning
they won't get updates from open file syncs, and during close their
contents are simply discarded.

As an extra benefit, LFS_O_CREAT | LFS_O_SNAPSHOT is equivalent to
Linux's O_TMPFILE, making it easy to create temporary, unnamed files.

This may be useful for embedded development, where unnamed flash-backed
buffers may provide a slower, but larger, alternative to RAM-backed
buffers.

.gitignore

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

.travis.yml

@@ -208,6 +208,38 @@ jobs:
     script:
       - make test TFLAGS+="-k --valgrind"
 
+  # test compilation in read-only mode
+  - stage: test
+    env:
+      - NAME=littlefs-readonly
+      - CC="arm-linux-gnueabi-gcc --static -mthumb"
+      - CFLAGS="-Werror -DLFS_READONLY"
+    if: branch !~ -prefix$
+    install:
+      - *install-common
+      - sudo apt-get install
+            gcc-arm-linux-gnueabi
+            libc6-dev-armel-cross
+      - arm-linux-gnueabi-gcc --version
+    # report-size will compile littlefs and report the size
+    script: [*report-size]
+
+  # test compilation in thread-safe mode
+  - stage: test
+    env:
+      - NAME=littlefs-threadsafe
+      - CC="arm-linux-gnueabi-gcc --static -mthumb"
+      - CFLAGS="-Werror -DLFS_THREADSAFE"
+    if: branch !~ -prefix$
+    install:
+      - *install-common
+      - sudo apt-get install
+            gcc-arm-linux-gnueabi
+            libc6-dev-armel-cross
+      - arm-linux-gnueabi-gcc --version
+    # report-size will compile littlefs and report the size
+    script: [*report-size]
+
   # self-host with littlefs-fuse for fuzz test
   - stage: test
     env:

Makefile

@@ -26,8 +26,6 @@ endif
 override CFLAGS += -I.
 override CFLAGS += -std=c99 -Wall -pedantic
 override CFLAGS += -Wextra -Wshadow -Wjump-misses-init -Wundef
-# Remove missing-field-initializers because of GCC bug
-override CFLAGS += -Wno-missing-field-initializers
 
 ifdef VERBOSE
 override TFLAGS += -v

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.
@@ -219,6 +222,11 @@ License Identifiers that are here available: http://spdx.org/licenses/
   want this, but it is handy for demos.  You can see it in action
   [here][littlefs-js-demo].
   
+- [littlefs-python] - A Python wrapper for littlefs. The project allows you
+  to create images of the filesystem on your PC. Check if littlefs will fit
+  your needs, create images for a later download to the target memory or
+  inspect the content of a binary image of the target memory.
+
 - [mklfs] - A command line tool built by the [Lua RTOS] guys for making
   littlefs images from a host PC. Supports Windows, Mac OS, and Linux.
 
@@ -247,3 +255,4 @@ License Identifiers that are here available: http://spdx.org/licenses/
 [LittleFileSystem]: https://os.mbed.com/docs/mbed-os/v5.12/apis/littlefilesystem.html
 [SPIFFS]: https://github.com/pellepl/spiffs
 [Dhara]: https://github.com/dlbeer/dhara
+[littlefs-python]: https://pypi.org/project/littlefs-python/

SPEC.md

@@ -289,8 +289,8 @@ Layout of the name tag:
 ```
         tag                          data
 [--      32      --][---        variable length        ---]
-[1| 3| 8 | 10 | 10 ][---            (size)             ---]
+[1| 3| 8 | 10 | 10 ][---          (size * 8)           ---]
- ^  ^  ^    ^    ^- size               ^- file name
+ ^  ^  ^    ^    ^- 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)             ---]
+[1|- 11 -| 10 | 10 ][---           (size * 8)          ---]
- ^    ^     ^    ^- size               ^- inline data
+ ^    ^     ^    ^- 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)             ---]
+[1| 3| 8 | 10 | 10 ][---           (size * 8)          ---]
- ^  ^  ^    ^    ^- size               ^- attr data
+ ^  ^  ^    ^    ^- 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)             ---]
+[1| 3| 8 | 10 | 10 ][--      32      --|---        (size * 8 - 32)        ---]
- ^  ^  ^    ^    ^            ^- crc                      ^- padding
+ ^  ^  ^    ^    ^            ^- crc                             ^- padding
- |  |  |    |    '- size (12)
+ |  |  |    |    '- 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;
     }
 
@@ -205,18 +207,18 @@ int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
         bd->power_cycles -= 1;
         if (bd->power_cycles == 0) {
             // sync to make sure we persist the last changes
-            assert(lfs_testbd_rawsync(cfg) == 0);
+            LFS_ASSERT(lfs_testbd_rawsync(cfg) == 0);
             // simulate power loss
             exit(33);
         }
     }
 
-    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;
     }
 
@@ -252,20 +254,20 @@ int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
         bd->power_cycles -= 1;
         if (bd->power_cycles == 0) {
             // sync to make sure we persist the last changes
-            assert(lfs_testbd_rawsync(cfg) == 0);
+            LFS_ASSERT(lfs_testbd_rawsync(cfg) == 0);
             // simulate power loss
             exit(33);
         }
     }
 
-    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.h

@@ -9,6 +9,7 @@
 
 #include <stdint.h>
 #include <stdbool.h>
+#include "lfs_util.h"
 
 #ifdef __cplusplus
 extern "C"
@@ -21,7 +22,7 @@ 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 0x00020003
 #define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
 #define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >>  0))
 
@@ -111,34 +112,41 @@ enum lfs_type {
     LFS_TYPE_INLINESTRUCT   = 0x201,
     LFS_TYPE_SOFTTAIL       = 0x600,
     LFS_TYPE_HARDTAIL       = 0x601,
-    LFS_TYPE_BRANCH         = 0x681,
     LFS_TYPE_MOVESTATE      = 0x7ff,
 
     // internal chip sources
     LFS_FROM_NOOP           = 0x000,
     LFS_FROM_MOVE           = 0x101,
-    LFS_FROM_DROP           = 0x102,
+    LFS_FROM_USERATTRS      = 0x102,
-    LFS_FROM_USERATTRS      = 0x103,
 };
 
 // File open flags
 enum lfs_open_flags {
     // open flags
-    LFS_O_RDONLY = 1,         // Open a file as read only
+    LFS_O_RDONLY    = 1,        // Open a file as read only
-    LFS_O_WRONLY = 2,         // Open a file as write only
+#ifndef LFS_READONLY
-    LFS_O_RDWR   = 3,         // Open a file as read and write
+    LFS_O_WRONLY    = 2,        // Open a file as write only
-    LFS_O_CREAT  = 0x0100,    // Create a file if it does not exist
+    LFS_O_RDWR      = 3,        // Open a file as read and write
-    LFS_O_EXCL   = 0x0200,    // Fail if a file already exists
+#endif
-    LFS_O_TRUNC  = 0x0400,    // Truncate the existing file to zero size
+
-    LFS_O_APPEND = 0x0800,    // Move to end of file on every write
+#ifndef LFS_READONLY
+    LFS_O_CREAT     = 0x0100,   // Create a file if it does not exist
+    LFS_O_EXCL      = 0x0200,   // Fail if a file already exists
+    LFS_O_TRUNC     = 0x0400,   // Truncate the existing file to zero size
+    LFS_O_APPEND    = 0x0800,   // Move to end of file on every write
+    LFS_O_SNAPSHOT  = 0x1000,   // Open a temporary snapshot, ignore changes
+#endif
 
     // internally used flags
-    LFS_F_DIRTY   = 0x010000, // File does not match storage
+#ifndef LFS_READONLY
-    LFS_F_WRITING = 0x020000, // File has been written since last flush
+    LFS_F_DIRTY     = 0x010000, // File does not match storage
-    LFS_F_READING = 0x040000, // File has been read since last flush
+#endif
-    LFS_F_ERRED   = 0x080000, // An error occured during write
+    LFS_F_READING   = 0x020000, // File has been read since last flush
-    LFS_F_INLINE  = 0x100000, // Currently inlined in directory entry
+#ifndef LFS_READONLY
-    LFS_F_OPENED  = 0x200000, // File has been opened
+    LFS_F_WRITING   = 0x040000, // File has been written since last flush
+    LFS_F_ZOMBIE    = 0x080000, // An error occurred during write
+#endif
+    LFS_F_INLINE    = 0x100000, // Currently inlined in directory entry
 };
 
 // File seek flags
@@ -176,6 +184,16 @@ struct lfs_config {
     // are propogated to the user.
     int (*sync)(const struct lfs_config *c);
 
+#ifdef LFS_THREADSAFE
+    // Lock the underlying block device. Negative error codes
+    // are propogated to the user.
+    int (*lock)(const struct lfs_config *c);
+
+    // Unlock the underlying block device. Negative error codes
+    // are propogated to the user.
+    int (*unlock)(const struct lfs_config *c);
+#endif
+
     // Minimum size of a block read. All read operations will be a
     // multiple of this value.
     lfs_size_t read_size;
@@ -280,16 +298,15 @@ struct lfs_file_config {
     void *buffer;
 
     // Optional list of custom attributes related to the file. If the file
-    // is opened with read access, these attributes will be read from disk
+    // is opened for reading, these attributes will be read from disk during
-    // during the open call. If the file is opened with write access, the
+    // open. If the file is open for writing, these attribute will be atomically
-    // attributes will be written to disk every file sync or close. This
+    // written to disk when the file is written to disk. Note that these
-    // write occurs atomically with update to the file's contents.
+    // attributes are not written unless the file is modified.
     //
     // Custom attributes are uniquely identified by an 8-bit type and limited
-    // to LFS_ATTR_MAX bytes. When read, if the stored attribute is smaller
+    // to LFS_ATTR_MAX bytes. If the stored attribute is larger than the
-    // than the buffer, it will be padded with zeros. If the stored attribute
+    // provided buffer, it will be silently truncated. If no attribute is
-    // is larger, then it will be silently truncated. If the attribute is not
+    // found, and the file is open for writing, it will be created implicitly.
-    // found, it will be created implicitly.
     struct lfs_attr *attrs;
 
     // Number of custom attributes in the list
@@ -312,11 +329,8 @@ typedef struct lfs_mdir {
     uint32_t etag;
     uint16_t count;
     bool erased;
-    bool first; // TODO come on
     bool split;
-    bool mustrelocate; // TODO not great either
     lfs_block_t tail[2];
-    lfs_block_t branch[2];
 } lfs_mdir_t;
 
 // littlefs directory type
@@ -371,9 +385,6 @@ typedef struct lfs {
     lfs_cache_t pcache;
 
     lfs_block_t root[2];
-    lfs_block_t relocate_tail[2];
-    lfs_block_t relocate_end[2];
-    bool relocate_do_hack; // TODO fixme
     struct lfs_mlist {
         struct lfs_mlist *next;
         uint16_t id;
@@ -407,6 +418,7 @@ typedef struct lfs {
 
 /// Filesystem functions ///
 
+#ifndef LFS_READONLY
 // Format a block device with the littlefs
 //
 // Requires a littlefs object and config struct. This clobbers the littlefs
@@ -415,6 +427,7 @@ typedef struct lfs {
 //
 // Returns a negative error code on failure.
 int lfs_format(lfs_t *lfs, const struct lfs_config *config);
+#endif
 
 // Mounts a littlefs
 //
@@ -434,12 +447,15 @@ int lfs_unmount(lfs_t *lfs);
 
 /// General operations ///
 
+#ifndef LFS_READONLY
 // Removes a file or directory
 //
 // If removing a directory, the directory must be empty.
 // Returns a negative error code on failure.
 int lfs_remove(lfs_t *lfs, const char *path);
+#endif
 
+#ifndef LFS_READONLY
 // Rename or move a file or directory
 //
 // If the destination exists, it must match the source in type.
@@ -447,6 +463,7 @@ int lfs_remove(lfs_t *lfs, const char *path);
 //
 // Returns a negative error code on failure.
 int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath);
+#endif
 
 // Find info about a file or directory
 //
@@ -457,10 +474,9 @@ int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info);
 // Get a custom attribute
 //
 // Custom attributes are uniquely identified by an 8-bit type and limited
-// to LFS_ATTR_MAX bytes. When read, if the stored attribute is smaller than
+// to LFS_ATTR_MAX bytes. If the stored attribute is larger than the
-// the buffer, it will be padded with zeros. If the stored attribute is larger,
+// provided buffer, it will be silently truncated. If no attribute is found,
-// then it will be silently truncated. If no attribute is found, the error
+// the error LFS_ERR_NOATTR is returned and the buffer is filled with zeros.
-// LFS_ERR_NOATTR is returned and the buffer is filled with zeros.
 //
 // Returns the size of the attribute, or a negative error code on failure.
 // Note, the returned size is the size of the attribute on disk, irrespective
@@ -469,6 +485,7 @@ int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info);
 lfs_ssize_t lfs_getattr(lfs_t *lfs, const char *path,
         uint8_t type, void *buffer, lfs_size_t size);
 
+#ifndef LFS_READONLY
 // Set custom attributes
 //
 // Custom attributes are uniquely identified by an 8-bit type and limited
@@ -478,13 +495,16 @@ lfs_ssize_t lfs_getattr(lfs_t *lfs, const char *path,
 // Returns a negative error code on failure.
 int lfs_setattr(lfs_t *lfs, const char *path,
         uint8_t type, const void *buffer, lfs_size_t size);
+#endif
 
+#ifndef LFS_READONLY
 // Removes a custom attribute
 //
 // If an attribute is not found, nothing happens.
 //
 // Returns a negative error code on failure.
 int lfs_removeattr(lfs_t *lfs, const char *path, uint8_t type);
+#endif
 
 
 /// File operations ///
@@ -533,6 +553,7 @@ int lfs_file_sync(lfs_t *lfs, lfs_file_t *file);
 lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
         void *buffer, lfs_size_t size);
 
+#ifndef LFS_READONLY
 // Write data to file
 //
 // Takes a buffer and size indicating the data to write. The file will not
@@ -541,6 +562,7 @@ lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
 // Returns the number of bytes written, or a negative error code on failure.
 lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
         const void *buffer, lfs_size_t size);
+#endif
 
 // Change the position of the file
 //
@@ -549,10 +571,12 @@ lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
 lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
         lfs_soff_t off, int whence);
 
+#ifndef LFS_READONLY
 // Truncates the size of the file to the specified size
 //
 // Returns a negative error code on failure.
 int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size);
+#endif
 
 // Return the position of the file
 //
@@ -575,10 +599,12 @@ lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file);
 
 /// Directory operations ///
 
+#ifndef LFS_READONLY
 // Create a directory
 //
 // Returns a negative error code on failure.
 int lfs_mkdir(lfs_t *lfs, const char *path);
+#endif
 
 // Open a directory
 //
@@ -640,6 +666,7 @@ lfs_ssize_t lfs_fs_size(lfs_t *lfs);
 // Returns a negative error code on failure.
 int lfs_fs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data);
 
+#ifndef LFS_READONLY
 #ifdef LFS_MIGRATE
 // Attempts to migrate a previous version of littlefs
 //
@@ -654,6 +681,7 @@ int lfs_fs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data);
 // Returns a negative error code on failure.
 int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg);
 #endif
+#endif
 
 
 #ifdef __cplusplus

lfs_util.h

@@ -50,31 +50,35 @@ extern "C"
 
 // Logging functions
 #ifdef LFS_YES_TRACE
-#define LFS_TRACE(fmt, ...) \
+#define LFS_TRACE_(fmt, ...) \
-    printf("%s:%d:trace: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+    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, ...) \
+#define LFS_DEBUG_(fmt, ...) \
-    printf("%s:%d:debug: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+    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, ...) \
+#define LFS_WARN_(fmt, ...) \
-    printf("%s:%d:warn: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+    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, ...) \
+#define LFS_ERROR_(fmt, ...) \
-    printf("%s:%d:error: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+    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

@@ -18,10 +18,9 @@ TAG_TYPES = {
     'ctzstruct':    (0x7ff, 0x202),
     'inlinestruct': (0x7ff, 0x201),
     'userattr':     (0x700, 0x300),
-    'tail':         (0x700, 0x600), # TODO rename these?
+    'tail':         (0x700, 0x600),
     'softtail':     (0x7ff, 0x600),
     'hardtail':     (0x7ff, 0x601),
-    'branch':       (0x7ff, 0x681),
     'gstate':       (0x700, 0x700),
     'movestate':    (0x7ff, 0x7ff),
     'crc':          (0x700, 0x500),
@@ -104,7 +103,7 @@ class Tag:
 
     def mkmask(self):
         return Tag(
-            0x780 if self.is_('tail') else 0x700 if self.isunique else 0x7ff, # TODO best way?
+            0x700 if self.isunique else 0x7ff,
             0x3ff if self.isattr else 0,
             0)
 
@@ -319,14 +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

@@ -5,107 +5,24 @@ import sys
 import json
 import io
 import itertools as it
-import collections as c
 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, mdirs, 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'):
-            pair = struct.unpack('<II', struct_.data[:8].ljust(8, b'\xff'))
-            desc += " dir {%#x, %#x}%s" % (
-                pair[0], pair[1],
-                '?' if frozenset(pair) not in mdirs else '')
-        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'
-    mdirs = c.OrderedDict()
+    dirs = []
+    mdirs = []
     corrupted = []
     cycle = False
     with open(args.disk, 'rb') as f:
         tail = (args.block1, args.block2)
-        while tail:
+        hard = False
-            if frozenset(tail) in mdirs:
+        while True:
-                # cycle detected
+            for m in it.chain((m for d in dirs for m in d), mdirs):
-                cycle = tail
+                if set(m.blocks) == set(tail):
+                    # cycle detected
+                    cycle = m.blocks
+            if cycle:
                 break
 
             # load mdir
@@ -128,13 +45,6 @@ def main(args):
             except KeyError:
                 mdir.tail = None
 
-            try:
-                mdir.branch = mdir[Tag('branch', 0, 0)]
-                if mdir.branch.size != 8 or mdir.branch.data == 8*b'\xff':
-                    mdir.branch = None
-            except KeyError:
-                mdir.branch = None
-
             # have superblock?
             try:
                 nsuperblock = mdir[
@@ -155,53 +65,39 @@ def main(args):
             if not mdir:
                 corrupted.append(mdir)
 
-            # add to metadata-pairs
+            # add to directories
-            mdirs[frozenset(mdir.blocks)] = mdir
+            mdirs.append(mdir)
-            tail = (struct.unpack('<II', mdir.tail.data)
+            if mdir.tail is None or not mdir.tail.is_('hardtail'):
-                if mdir.tail else None)
+                dirs.append(mdirs)
+                mdirs = []
 
-    # derive paths and build directories
+            if mdir.tail is None:
-    dirs = {}
+                break
-    rogue = {}
+
-    pending = [('/', (args.block1, args.block2))]
+            tail = struct.unpack('<II', mdir.tail.data)
+            hard = mdir.tail.is_('hardtail')
+
+    # find paths
+    dirtable = {}
+    for dir in dirs:
+        dirtable[frozenset(dir[0].blocks)] = dir
+
+    pending = [("/", dirs[0])]
     while pending:
-        path, branch = pending.pop(0)
+        path, dir = pending.pop(0)
-        dir = []
+        for mdir in dir:
-        while branch and frozenset(branch) in mdirs:
-            mdir = mdirs[frozenset(branch)]
-            dir.append(mdir)
-
             for tag in mdir.tags:
                 if tag.is_('dir'):
                     try:
-                        npath = path + '/' + tag.data.decode('utf8')
+                        npath = tag.data.decode('utf8')
-                        npath = npath.replace('//', '/')
                         dirstruct = mdir[Tag('dirstruct', tag.id, 0)]
-                        npair = struct.unpack('<II', dirstruct.data)
+                        nblocks = struct.unpack('<II', dirstruct.data)
-                        pending.append((npath, npair))
+                        nmdir = dirtable[frozenset(nblocks)]
+                        pending.append(((path + '/' + npath), nmdir))
                     except KeyError:
                         pass
 
-            branch = (struct.unpack('<II', mdir.branch.data)
+        dir[0].path = path.replace('//', '/')
-                if mdir.branch else None)
-
-        if not dir:
-            rogue[path] = branch
-        else:
-            dirs[path] = dir
-
-    # also find orphans
-    not_orphans = {frozenset(mdir.blocks)
-        for dir in dirs.values()
-        for mdir in dir}
-    orphans = []
-    for pair, mdir in mdirs.items():
-        if pair not in not_orphans:
-            if len(orphans) > 0 and (pair == frozenset(
-                    struct.unpack('<II', orphans[-1][-1].tail.data))):
-                orphans[-1].append(mdir)
-            else:
-                orphans.append([mdir])
 
     # print littlefs + version info
     version = ('?', '?')
@@ -210,28 +106,22 @@ def main(args):
             struct.unpack('<HH', superblock[1].data[0:4].ljust(4, b'\xff'))))
     print("%-47s%s" % ("littlefs v%s.%s" % version,
         "data (truncated, if it fits)"
-        if not any([args.no_truncate, args.tags, args.log, args.all]) else ""))
+        if not any([args.no_truncate, args.log, args.all]) else ""))
 
     # print gstate
-    badgstate = None
     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:
-        if frozenset(blocks) not in mdirs:
+        print("  move dir {%#x, %#x} id %d" % (
-            badgstate = gstate
+            blocks[0], blocks[1], tag.id))
-        print("  move dir {%#x, %#x}%s id %d" % (
-            blocks[0], blocks[1],
-            '?' if frozenset(blocks) not in mdirs else '',
-            tag.id))
 
-    # print dir info
+    # print mdir info
-    for path, dir in it.chain(
+    for i, dir in enumerate(dirs):
-            sorted(dirs.items()),
+        print("dir %s" % (json.dumps(dir[0].path)
-            zip(it.repeat(None), orphans)):
+            if hasattr(dir[0], 'path') else '(orphan)'))
-        print("dir %s" % json.dumps(path) if path else "orphaned")
 
         for j, mdir in enumerate(dir):
             print("mdir {%#x, %#x} rev %d (was %d)%s%s" % (
@@ -241,21 +131,19 @@ def main(args):
                 if mdir.tail else ''))
 
             f = io.StringIO()
-            if args.tags:
+            if args.log:
-                mdir.dump_tags(f, truncate=not args.no_truncate)
-            elif 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, mdirs, 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 j == len(dir)-1 else
                     'v' if k == len(lines)-1 else
-                    '|' if path else '.',
+                    '|',
                     line))
 
     errcode = 0
@@ -264,18 +152,8 @@ def main(args):
         print("*** corrupted mdir {%#x, %#x}! ***" % (
             mdir.blocks[0], mdir.blocks[1]))
 
-    for path, pair in rogue.items():
-        errcode = errcode or 2
-        print("*** couldn't find dir %s {%#x, %#x}! ***" % (
-            json.dumps(path), pair[0], pair[1]))
-
-    if badgstate:
-        errcode = errcode or 3
-        print("*** bad gstate 0x%s! ***" %
-            ''.join('%02x' % c for c in gstate))
-
     if cycle:
-        errcode = errcode or 4
+        errcode = errcode or 2
         print("*** cycle detected {%#x, %#x}! ***" % (
             cycle[0], cycle[1]))
 
@@ -292,12 +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.")
+        help="Optional second block address for finding the superblock.")
-    parser.add_argument('-t', '--tags', action='store_true',
-        help="Show metadata tags instead of reconstructing entries.")
     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' or isinstance(gdb, int):
+            elif gdb == 'main':
                 ncmd.extend([
                     '-ex', 'b %s:%d' % (self.suite.path, self.code_lineno),
                     '-ex', 'r'])
@@ -329,9 +329,7 @@ class ReentrantTestCase(TestCase):
                 persist = 'noerase'
 
             # exact cycle we should drop into debugger?
-            if gdb and failure and (
+            if gdb and failure and failure.cycleno == cycles:
-                    failure.cycleno == cycles or
-                    (isinstance(gdb, int) and gdb == cycles)):
                 return super().test(gdb=gdb, persist=persist, cycles=cycles,
                     failure=failure, **args)
 
@@ -762,8 +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', metavar='{init,start,assert},CYCLE',
+    parser.add_argument('-g', '--gdb', choices=['init', 'main', 'assert'],
-        type=lambda n: n if n in {'init', 'start', 'assert'} else int(n, 0),
         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_attrs.toml

@@ -16,41 +16,39 @@ code = '''
     lfs_getattr(&lfs, "hello", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "hello", 'B', buffer+4,  6) => 6;
     lfs_getattr(&lfs, "hello", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",   4) => 0;
+    assert(memcmp(buffer,    "aaaa",   4) == 0);
-    memcmp(buffer+4,  "bbbbbb", 6) => 0;
+    assert(memcmp(buffer+4,  "bbbbbb", 6) == 0);
-    memcmp(buffer+10, "ccccc",  5) => 0;
+    assert(memcmp(buffer+10, "ccccc",  5) == 0);
 
     lfs_setattr(&lfs, "hello", 'B', "", 0) => 0;
     lfs_getattr(&lfs, "hello", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "hello", 'B', buffer+4,  6) => 0;
     lfs_getattr(&lfs, "hello", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",         4) => 0;
+    assert(memcmp(buffer,    "aaaa",         4) == 0);
-    memcmp(buffer+4,  "\0\0\0\0\0\0", 6) => 0;
+    assert(memcmp(buffer+10, "ccccc",        5) == 0);
-    memcmp(buffer+10, "ccccc",        5) => 0;
 
     lfs_removeattr(&lfs, "hello", 'B') => 0;
     lfs_getattr(&lfs, "hello", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "hello", 'B', buffer+4,  6) => LFS_ERR_NOATTR;
     lfs_getattr(&lfs, "hello", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",         4) => 0;
+    assert(memcmp(buffer,    "aaaa",         4) == 0);
-    memcmp(buffer+4,  "\0\0\0\0\0\0", 6) => 0;
+    assert(memcmp(buffer+10, "ccccc",        5) == 0);
-    memcmp(buffer+10, "ccccc",        5) => 0;
 
     lfs_setattr(&lfs, "hello", 'B', "dddddd", 6) => 0;
     lfs_getattr(&lfs, "hello", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "hello", 'B', buffer+4,  6) => 6;
     lfs_getattr(&lfs, "hello", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",   4) => 0;
+    assert(memcmp(buffer,    "aaaa",   4) == 0);
-    memcmp(buffer+4,  "dddddd", 6) => 0;
+    assert(memcmp(buffer+4,  "dddddd", 6) == 0);
-    memcmp(buffer+10, "ccccc",  5) => 0;
+    assert(memcmp(buffer+10, "ccccc",  5) == 0);
 
     lfs_setattr(&lfs, "hello", 'B', "eee", 3) => 0;
     lfs_getattr(&lfs, "hello", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "hello", 'B', buffer+4,  6) => 3;
     lfs_getattr(&lfs, "hello", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",      4) => 0;
+    assert(memcmp(buffer,    "aaaa",  4) == 0);
-    memcmp(buffer+4,  "eee\0\0\0", 6) => 0;
+    assert(memcmp(buffer+4,  "eee",   3) == 0);
-    memcmp(buffer+10, "ccccc",     5) => 0;
+    assert(memcmp(buffer+10, "ccccc", 5) == 0);
 
     lfs_setattr(&lfs, "hello", 'A', buffer, LFS_ATTR_MAX+1) => LFS_ERR_NOSPC;
     lfs_setattr(&lfs, "hello", 'B', "fffffffff", 9) => 0;
@@ -65,13 +63,13 @@ code = '''
     lfs_getattr(&lfs, "hello", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "hello", 'B', buffer+4,  9) => 9;
     lfs_getattr(&lfs, "hello", 'C', buffer+13, 5) => 5;
-    memcmp(buffer,    "aaaa",      4) => 0;
+    assert(memcmp(buffer,    "aaaa",      4) == 0);
-    memcmp(buffer+4,  "fffffffff", 9) => 0;
+    assert(memcmp(buffer+4,  "fffffffff", 9) == 0);
-    memcmp(buffer+13, "ccccc",     5) => 0;
+    assert(memcmp(buffer+13, "ccccc",     5) == 0);
 
     lfs_file_open(&lfs, &file, "hello/hello", LFS_O_RDONLY) => 0;
     lfs_file_read(&lfs, &file, buffer, sizeof(buffer)) => strlen("hello");
-    memcmp(buffer, "hello", strlen("hello")) => 0;
+    assert(memcmp(buffer, "hello", strlen("hello")) == 0);
     lfs_file_close(&lfs, &file);
     lfs_unmount(&lfs) => 0;
 '''
@@ -94,41 +92,39 @@ code = '''
     lfs_getattr(&lfs, "/", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "/", 'B', buffer+4,  6) => 6;
     lfs_getattr(&lfs, "/", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",   4) => 0;
+    assert(memcmp(buffer,    "aaaa",   4) == 0);
-    memcmp(buffer+4,  "bbbbbb", 6) => 0;
+    assert(memcmp(buffer+4,  "bbbbbb", 6) == 0);
-    memcmp(buffer+10, "ccccc",  5) => 0;
+    assert(memcmp(buffer+10, "ccccc",  5) == 0);
 
     lfs_setattr(&lfs, "/", 'B', "", 0) => 0;
     lfs_getattr(&lfs, "/", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "/", 'B', buffer+4,  6) => 0;
     lfs_getattr(&lfs, "/", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",         4) => 0;
+    assert(memcmp(buffer,    "aaaa",  4) == 0);
-    memcmp(buffer+4,  "\0\0\0\0\0\0", 6) => 0;
+    assert(memcmp(buffer+10, "ccccc", 5) == 0);
-    memcmp(buffer+10, "ccccc",        5) => 0;
 
     lfs_removeattr(&lfs, "/", 'B') => 0;
     lfs_getattr(&lfs, "/", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "/", 'B', buffer+4,  6) => LFS_ERR_NOATTR;
     lfs_getattr(&lfs, "/", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",         4) => 0;
+    assert(memcmp(buffer,    "aaaa",  4) == 0);
-    memcmp(buffer+4,  "\0\0\0\0\0\0", 6) => 0;
+    assert(memcmp(buffer+10, "ccccc", 5) == 0);
-    memcmp(buffer+10, "ccccc",        5) => 0;
 
     lfs_setattr(&lfs, "/", 'B', "dddddd", 6) => 0;
     lfs_getattr(&lfs, "/", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "/", 'B', buffer+4,  6) => 6;
     lfs_getattr(&lfs, "/", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",   4) => 0;
+    assert(memcmp(buffer,    "aaaa",   4) == 0);
-    memcmp(buffer+4,  "dddddd", 6) => 0;
+    assert(memcmp(buffer+4,  "dddddd", 6) == 0);
-    memcmp(buffer+10, "ccccc",  5) => 0;
+    assert(memcmp(buffer+10, "ccccc",  5) == 0);
 
     lfs_setattr(&lfs, "/", 'B', "eee", 3) => 0;
     lfs_getattr(&lfs, "/", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "/", 'B', buffer+4,  6) => 3;
     lfs_getattr(&lfs, "/", 'C', buffer+10, 5) => 5;
-    memcmp(buffer,    "aaaa",      4) => 0;
+    assert(memcmp(buffer,    "aaaa",  4) == 0);
-    memcmp(buffer+4,  "eee\0\0\0", 6) => 0;
+    assert(memcmp(buffer+4,  "eee",   3) == 0);
-    memcmp(buffer+10, "ccccc",     5) => 0;
+    assert(memcmp(buffer+10, "ccccc", 5) == 0);
 
     lfs_setattr(&lfs, "/", 'A', buffer, LFS_ATTR_MAX+1) => LFS_ERR_NOSPC;
     lfs_setattr(&lfs, "/", 'B', "fffffffff", 9) => 0;
@@ -142,13 +138,13 @@ code = '''
     lfs_getattr(&lfs, "/", 'A', buffer,    4) => 4;
     lfs_getattr(&lfs, "/", 'B', buffer+4,  9) => 9;
     lfs_getattr(&lfs, "/", 'C', buffer+13, 5) => 5;
-    memcmp(buffer,    "aaaa",      4) => 0;
+    assert(memcmp(buffer,    "aaaa",      4) == 0);
-    memcmp(buffer+4,  "fffffffff", 9) => 0;
+    assert(memcmp(buffer+4,  "fffffffff", 9) == 0);
-    memcmp(buffer+13, "ccccc",     5) => 0;
+    assert(memcmp(buffer+13, "ccccc",     5) == 0);
 
     lfs_file_open(&lfs, &file, "hello/hello", LFS_O_RDONLY) => 0;
     lfs_file_read(&lfs, &file, buffer, sizeof(buffer)) => strlen("hello");
-    memcmp(buffer, "hello", strlen("hello")) => 0;
+    assert(memcmp(buffer, "hello", strlen("hello")) == 0);
     lfs_file_close(&lfs, &file);
     lfs_unmount(&lfs) => 0;
 '''
@@ -176,52 +172,55 @@ code = '''
     memcpy(buffer,    "aaaa",   4);
     memcpy(buffer+4,  "bbbbbb", 6);
     memcpy(buffer+10, "ccccc",  5);
+    lfs_file_write(&lfs, &file, "hi", 2) => 2;
     lfs_file_close(&lfs, &file) => 0;
     memset(buffer, 0, 15);
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_RDONLY, &cfg1) => 0;
     lfs_file_close(&lfs, &file) => 0;
-    memcmp(buffer,    "aaaa",   4) => 0;
+    assert(memcmp(buffer,    "aaaa",   4) == 0);
-    memcmp(buffer+4,  "bbbbbb", 6) => 0;
+    assert(memcmp(buffer+4,  "bbbbbb", 6) == 0);
-    memcmp(buffer+10, "ccccc",  5) => 0;
+    assert(memcmp(buffer+10, "ccccc",  5) == 0);
 
     attrs1[1].size = 0;
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_WRONLY, &cfg1) => 0;
+    lfs_file_write(&lfs, &file, "hi", 2) => 2;
     lfs_file_close(&lfs, &file) => 0;
     memset(buffer, 0, 15);
     attrs1[1].size = 6;
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_RDONLY, &cfg1) => 0;
     lfs_file_close(&lfs, &file) => 0;
-    memcmp(buffer,    "aaaa",         4) => 0;
+    assert(memcmp(buffer,    "aaaa",  4) == 0);
-    memcmp(buffer+4,  "\0\0\0\0\0\0", 6) => 0;
+    assert(memcmp(buffer+10, "ccccc", 5) == 0);
-    memcmp(buffer+10, "ccccc",        5) => 0;
 
     attrs1[1].size = 6;
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_WRONLY, &cfg1) => 0;
     memcpy(buffer+4,  "dddddd", 6);
+    lfs_file_write(&lfs, &file, "hi", 2) => 2;
     lfs_file_close(&lfs, &file) => 0;
     memset(buffer, 0, 15);
     attrs1[1].size = 6;
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_RDONLY, &cfg1) => 0;
     lfs_file_close(&lfs, &file) => 0;
-    memcmp(buffer,    "aaaa",   4) => 0;
+    assert(memcmp(buffer,    "aaaa",   4) == 0);
-    memcmp(buffer+4,  "dddddd", 6) => 0;
+    assert(memcmp(buffer+4,  "dddddd", 6) == 0);
-    memcmp(buffer+10, "ccccc",  5) => 0;
+    assert(memcmp(buffer+10, "ccccc",  5) == 0);
 
     attrs1[1].size = 3;
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_WRONLY, &cfg1) => 0;
     memcpy(buffer+4,  "eee", 3);
+    lfs_file_write(&lfs, &file, "hi", 2) => 2;
     lfs_file_close(&lfs, &file) => 0;
     memset(buffer, 0, 15);
     attrs1[1].size = 6;
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_RDONLY, &cfg1) => 0;
     lfs_file_close(&lfs, &file) => 0;
-    memcmp(buffer,    "aaaa",      4) => 0;
+    assert(memcmp(buffer,    "aaaa",  4) == 0);
-    memcmp(buffer+4,  "eee\0\0\0", 6) => 0;
+    assert(memcmp(buffer+4,  "eee",   3) == 0);
-    memcmp(buffer+10, "ccccc",     5) => 0;
+    assert(memcmp(buffer+10, "ccccc", 5) == 0);
 
     attrs1[0].size = LFS_ATTR_MAX+1;
-    lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_WRONLY, &cfg1)
+    lfs_file_opencfg(&lfs, &file, "hello/hello2",
-        => LFS_ERR_NOSPC;
+            LFS_O_WRONLY | LFS_O_CREAT, &cfg1) => LFS_ERR_NOSPC;
 
     struct lfs_attr attrs2[] = {
         {'A', buffer,    4},
@@ -231,6 +230,7 @@ code = '''
     struct lfs_file_config cfg2 = {.attrs=attrs2, .attr_count=3};
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_RDWR, &cfg2) => 0;
     memcpy(buffer+4,  "fffffffff", 9);
+    lfs_file_write(&lfs, &file, "hi", 2) => 2;
     lfs_file_close(&lfs, &file) => 0;
     attrs1[0].size = 4;
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_RDONLY, &cfg1) => 0;
@@ -249,13 +249,13 @@ code = '''
 
     lfs_file_opencfg(&lfs, &file, "hello/hello", LFS_O_RDONLY, &cfg3) => 0;
     lfs_file_close(&lfs, &file) => 0;
-    memcmp(buffer,    "aaaa",      4) => 0;
+    assert(memcmp(buffer,    "aaaa",      4) == 0);
-    memcmp(buffer+4,  "fffffffff", 9) => 0;
+    assert(memcmp(buffer+4,  "fffffffff", 9) == 0);
-    memcmp(buffer+13, "ccccc",     5) => 0;
+    assert(memcmp(buffer+13, "ccccc",     5) == 0);
 
     lfs_file_open(&lfs, &file, "hello/hello", LFS_O_RDONLY) => 0;
     lfs_file_read(&lfs, &file, buffer, sizeof(buffer)) => strlen("hello");
-    memcmp(buffer, "hello", strlen("hello")) => 0;
+    assert(memcmp(buffer, "hillo", strlen("hello")) == 0);
     lfs_file_close(&lfs, &file);
     lfs_unmount(&lfs) => 0;
 '''
@@ -287,17 +287,16 @@ code = '''
     lfs_getattr(&lfs, "hello/hello", 'B', buffer,    9) => 9;
     lfs_getattr(&lfs, "hello/hello", 'C', buffer+9,  9) => 5;
     lfs_getattr(&lfs, "hello/hello", 'D', buffer+18, 9) => LFS_ERR_NOATTR;
-    memcmp(buffer,    "fffffffff",          9) => 0;
+    assert(memcmp(buffer,    "fffffffff", 9) == 0);
-    memcmp(buffer+9,  "ccccc\0\0\0\0",      9) => 0;
+    assert(memcmp(buffer+9,  "ccccc",     5) == 0);
-    memcmp(buffer+18, "\0\0\0\0\0\0\0\0\0", 9) => 0;
 
+    lfs_file_write(&lfs, &file, "hi", 2) => 2;
     lfs_file_sync(&lfs, &file) => 0;
     lfs_getattr(&lfs, "hello/hello", 'B', buffer,    9) => 4;
     lfs_getattr(&lfs, "hello/hello", 'C', buffer+9,  9) => 0;
     lfs_getattr(&lfs, "hello/hello", 'D', buffer+18, 9) => 4;
-    memcmp(buffer,    "gggg\0\0\0\0\0",     9) => 0;
+    assert(memcmp(buffer,    "gggg", 4) == 0);
-    memcmp(buffer+9,  "\0\0\0\0\0\0\0\0\0", 9) => 0;
+    assert(memcmp(buffer+18, "hhhh", 4) == 0);
-    memcmp(buffer+18, "hhhh\0\0\0\0\0",     9) => 0;
 
     lfs_file_close(&lfs, &file) => 0;
     lfs_unmount(&lfs) => 0;

tests/test_dirs.toml

@@ -246,8 +246,6 @@ code = '''
                 LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
         lfs_file_close(&lfs, &file) => 0;
     }
-    // TODO rm me
-    lfs_mkdir(&lfs, "a") => 0;
     lfs_unmount(&lfs) => 0;
 
     lfs_mount(&lfs, &cfg) => 0;
@@ -258,9 +256,6 @@ code = '''
     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, "a") == 0);
     for (int i = 0; i < N; i++) {
         sprintf(path, "file%03d", i);
         lfs_dir_read(&lfs, &dir, &info) => 1;

tests/test_evil.toml

@@ -151,6 +151,7 @@ code = '''
             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;
@@ -245,6 +246,7 @@ code = '''
             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(
@@ -274,6 +276,7 @@ code = '''
             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(

tests/test_interspersed.toml

@@ -242,3 +242,695 @@ code = '''
 
     lfs_unmount(&lfs) => 0;
 '''
+
+[[case]] # open same file reading from separate file handles
+define.READERS = 3
+define.SIZE = [10, 100, 1000, 10000]
+define.RDMODE = ['LFS_O_RDONLY', 'LFS_O_RDWR']
+code = '''
+    const char alphas[] = "abcdefghijklmnopqrstuvwxyz";
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, "shared", LFS_O_CREAT | LFS_O_WRONLY) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &file, &alphas[j % 26], 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // open all files
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_t readers[READERS];
+    for (int i = 0; i < READERS; i++) {
+        lfs_file_open(&lfs, &readers[i], "shared", RDMODE) => 0;
+    }
+
+    // perform operations while all readers are open
+    for (int i = 0; i < READERS; i++) {
+        for (int j = 0; j < SIZE; j++) {
+            lfs_file_read(&lfs, &readers[i], buffer, 1) => 1;
+            assert(buffer[0] == alphas[j % 26]);
+        }
+    }
+
+    for (int i = 0; i < READERS; i++) {
+        lfs_file_close(&lfs, &readers[i]) => 0;
+    }
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # open same file reading and writing from separate file handles
+define.READERS = 3
+define.SIZE = [10, 100, 1000, 10000]
+define.RDMODE = ['LFS_O_RDONLY', 'LFS_O_RDWR']
+define.WRMODE = ['LFS_O_WRONLY', 'LFS_O_RDWR']
+code = '''
+    const char alphas[] = "abcdefghijklmnopqrstuvwxyz";
+    const char nums[] = "0123456789";
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, "shared", LFS_O_CREAT | LFS_O_WRONLY) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &file, &alphas[j % 26], 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // open all files
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_t writer;
+    lfs_file_t readers[READERS];
+    lfs_file_open(&lfs, &writer, "shared", WRMODE) => 0;
+    for (int i = 0; i < READERS; i++) {
+        lfs_file_open(&lfs, &readers[i], "shared", RDMODE) => 0;
+    }
+
+    // perform operations while all readers are open
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &writer, &nums[j % 10], 1) => 1;
+    }
+
+    for (int i = 0; i < READERS; i++) {
+        for (int j = 0; j < SIZE/2; j++) {
+            lfs_file_read(&lfs, &readers[i], buffer, 1) => 1;
+            assert(buffer[0] == alphas[j % 26]);
+        }
+    }
+
+    // sync, now write should reflect in all open files
+    lfs_file_sync(&lfs, &writer) => 0;
+
+    for (int i = 0; i < READERS; i++) {
+        for (int j = SIZE/2; j < SIZE; j++) {
+            lfs_file_read(&lfs, &readers[i], buffer, 1) => 1;
+            assert(buffer[0] == nums[j % 10]);
+        }
+    }
+
+    // double check our writer reflects its own changes
+    if (WRMODE == LFS_O_RDWR) {
+        lfs_file_rewind(&lfs, &writer) => 0;
+        for (int j = 0; j < SIZE; j++) {
+            lfs_file_read(&lfs, &writer, buffer, 1) => 1;
+            assert(buffer[0] == nums[j % 10]);
+        }
+    }
+
+    for (int i = 0; i < READERS; i++) {
+        lfs_file_close(&lfs, &readers[i]) => 0;
+    }
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # check that attributes are updated in open files
+define.READERS = 3
+define.SIZE = 10
+define.RDMODE = ['LFS_O_RDONLY', 'LFS_O_RDWR']
+define.WRMODE = ['LFS_O_WRONLY', 'LFS_O_RDWR']
+code = '''
+    const char alphas[] = "abcdefghijklmnopqrstuvwxyz";
+    const char nums[] = "0123456789";
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    const struct lfs_file_config filecfg = {
+        .attr_count = 3,
+        .attrs = (struct lfs_attr[]){
+            {'A', "a",   1},
+            {'B', "bb",  2},
+            {'C', "ccc", 3},
+        },
+    };
+    lfs_file_opencfg(&lfs, &file, "shared",
+            LFS_O_CREAT | LFS_O_WRONLY, &filecfg) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &file, &alphas[j % 26], 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // open all files
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_t writer;
+    const struct lfs_file_config writercfg = {
+        .attr_count = 3,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[1]){0}, 1},
+            {'B', &(uint8_t[2]){0}, 2},
+            {'C', &(uint8_t[3]){0}, 3}}};
+    lfs_file_t readers[READERS];
+    const struct lfs_file_config readercfgs[READERS] = {
+        {   .attr_count = 3,
+            .attrs = (struct lfs_attr[]){
+                {'A', &(uint8_t[1]){0}, 1},
+                {'B', &(uint8_t[2]){0}, 2},
+                {'C', &(uint8_t[3]){0}, 3}}},
+        {   .attr_count = 3,
+            .attrs = (struct lfs_attr[]){
+                {'A', &(uint8_t[1]){0}, 1},
+                {'B', &(uint8_t[2]){0}, 2},
+                {'C', &(uint8_t[3]){0}, 3}}},
+        {   .attr_count = 3,
+            .attrs = (struct lfs_attr[]){
+                {'A', &(uint8_t[1]){0}, 1},
+                {'B', &(uint8_t[2]){0}, 2},
+                {'C', &(uint8_t[3]){0}, 3}}}};
+    lfs_file_opencfg(&lfs, &writer, "shared",
+            WRMODE, &writercfg) => 0;
+    for (int i = 0; i < READERS; i++) {
+        lfs_file_opencfg(&lfs, &readers[i], "shared",
+                RDMODE, &readercfgs[i]) => 0;
+    }
+
+    // perform operations while all readers are open
+    writercfg.attrs[0].size = 1;
+    memcpy(writercfg.attrs[0].buffer, "0", 1);
+    writercfg.attrs[1].size = 2;
+    memcpy(writercfg.attrs[1].buffer, "11", 2);
+    writercfg.attrs[2].size = 3;
+    memcpy(writercfg.attrs[2].buffer, "222", 3);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &writer, &nums[j % 10], 1) => 1;
+    }
+
+    for (int i = 0; i < READERS; i++) {
+        assert(readercfgs[i].attrs[0].size == 1);
+        assert(memcmp(readercfgs[i].attrs[0].buffer, "a", 1) == 0);
+        assert(readercfgs[i].attrs[1].size == 2);
+        assert(memcmp(readercfgs[i].attrs[1].buffer, "bb", 2) == 0);
+        assert(readercfgs[i].attrs[2].size == 3);
+        assert(memcmp(readercfgs[i].attrs[2].buffer, "ccc", 3) == 0);
+        for (int j = 0; j < SIZE; j++) {
+            lfs_file_read(&lfs, &readers[i], buffer, 1) => 1;
+            assert(buffer[0] == alphas[j % 26]);
+        }
+    }
+
+    // sync, now write should reflect in all open files
+    lfs_file_sync(&lfs, &writer) => 0;
+
+    for (int i = 0; i < READERS; i++) {
+        assert(readercfgs[i].attrs[0].size == 1);
+        assert(memcmp(readercfgs[i].attrs[0].buffer, "0", 1) == 0);
+        assert(readercfgs[i].attrs[1].size == 2);
+        assert(memcmp(readercfgs[i].attrs[1].buffer, "11", 2) == 0);
+        assert(readercfgs[i].attrs[2].size == 3);
+        assert(memcmp(readercfgs[i].attrs[2].buffer, "222", 3) == 0);
+        lfs_file_rewind(&lfs, &readers[i]) => 0;
+        for (int j = 0; j < SIZE; j++) {
+            lfs_file_read(&lfs, &readers[i], buffer, 1) => 1;
+            assert(buffer[0] == nums[j % 10]);
+        }
+    }
+
+    // double check our writer reflects its own changes
+    if (WRMODE == LFS_O_RDWR) {
+        assert(writercfg.attrs[0].size == 1);
+        assert(memcmp(writercfg.attrs[0].buffer, "0", 1) == 0);
+        assert(writercfg.attrs[1].size == 2);
+        assert(memcmp(writercfg.attrs[1].buffer, "11", 2) == 0);
+        assert(writercfg.attrs[2].size == 3);
+        assert(memcmp(writercfg.attrs[2].buffer, "222", 3) == 0);
+        lfs_file_rewind(&lfs, &writer) => 0;
+        for (int j = 0; j < SIZE; j++) {
+            lfs_file_read(&lfs, &writer, buffer, 1) => 1;
+            assert(buffer[0] == nums[j % 10]);
+        }
+    }
+
+    // now try explicit lfs_setattr calls, this should still update open files
+    lfs_setattr(&lfs, "shared", 'A', "A",   1) => 0;
+    lfs_setattr(&lfs, "shared", 'B', "BB",  2) => 0;
+    lfs_setattr(&lfs, "shared", 'C', "CCC", 3) => 0;
+
+    for (int i = 0; i < READERS; i++) {
+        assert(readercfgs[i].attrs[0].size == 1);
+        assert(memcmp(readercfgs[i].attrs[0].buffer, "A", 1) == 0);
+        assert(readercfgs[i].attrs[1].size == 2);
+        assert(memcmp(readercfgs[i].attrs[1].buffer, "BB", 2) == 0);
+        assert(readercfgs[i].attrs[2].size == 3);
+        assert(memcmp(readercfgs[i].attrs[2].buffer, "CCC", 3) == 0);
+        lfs_file_rewind(&lfs, &readers[i]) => 0;
+        for (int j = 0; j < SIZE; j++) {
+            lfs_file_read(&lfs, &readers[i], buffer, 1) => 1;
+            assert(buffer[0] == nums[j % 10]);
+        }
+    }
+
+    if (WRMODE == LFS_O_RDWR) {
+        assert(writercfg.attrs[0].size == 1);
+        assert(memcmp(writercfg.attrs[0].buffer, "A", 1) == 0);
+        assert(writercfg.attrs[1].size == 2);
+        assert(memcmp(writercfg.attrs[1].buffer, "BB", 2) == 0);
+        assert(writercfg.attrs[2].size == 3);
+        assert(memcmp(writercfg.attrs[2].buffer, "CCC", 3) == 0);
+        lfs_file_rewind(&lfs, &writer) => 0;
+        for (int j = 0; j < SIZE; j++) {
+            lfs_file_read(&lfs, &writer, buffer, 1) => 1;
+            assert(buffer[0] == nums[j % 10]);
+        }
+    } else if (WRMODE == LFS_O_WRONLY) {
+        // this should NOT update wronly attributes, these may be
+        // stored in read-only memory
+        assert(writercfg.attrs[0].size == 1);
+        assert(memcmp(writercfg.attrs[0].buffer, "0", 1) == 0);
+        assert(writercfg.attrs[1].size == 2);
+        assert(memcmp(writercfg.attrs[1].buffer, "11", 2) == 0);
+        assert(writercfg.attrs[2].size == 3);
+        assert(memcmp(writercfg.attrs[2].buffer, "222", 3) == 0);
+    }
+
+    for (int i = 0; i < READERS; i++) {
+        lfs_file_close(&lfs, &readers[i]) => 0;
+    }
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # simple snapshot for reading
+define.SIZE = [10, 100, 1000, 10000]
+code = '''
+    const char alphas[] = "abcdefghijklmnopqrstuvwxyz";
+    const char nums[] = "0123456789";
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    const struct lfs_file_config filecfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', "abcd", 4},
+        },
+    };
+    lfs_file_opencfg(&lfs, &file, "open_me",
+            LFS_O_CREAT | LFS_O_WRONLY, &filecfg) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &file, &alphas[j % 26], 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // open reader/writer/snapshot
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_t reader;
+    const struct lfs_file_config readercfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_t writer;
+    const struct lfs_file_config writercfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_t snapshot;
+    const struct lfs_file_config snapshotcfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    lfs_file_opencfg(&lfs, &writer, "open_me",
+            LFS_O_WRONLY, &writercfg) => 0;
+    lfs_file_opencfg(&lfs, &snapshot, "open_me",
+            LFS_O_RDONLY | LFS_O_SNAPSHOT, &snapshotcfg) => 0;
+
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE/2; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    assert(memcmp(snapshotcfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE/2; j++) {
+        lfs_file_read(&lfs, &snapshot, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    // write file
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &writer, &nums[j % 10], 1) => 1;
+    }
+    memcpy(writercfg.attrs[0].buffer, "0123", 4);
+    lfs_file_sync(&lfs, &writer) => 0;
+
+    // reader should change
+    assert(memcmp(readercfg.attrs[0].buffer, "0123", 4) == 0);
+    for (int j = SIZE/2; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+
+    // snapshot should remain unchanged
+    assert(memcmp(snapshotcfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = SIZE/2; j < SIZE; j++) {
+        lfs_file_read(&lfs, &snapshot, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_file_close(&lfs, &writer) => 0;
+    lfs_file_close(&lfs, &snapshot) => 0;
+
+    // disk should change
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "0123", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "0123", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # simple snapshot for writing
+define.SIZE = [10, 100, 1000, 10000]
+code = '''
+    const char alphas[] = "abcdefghijklmnopqrstuvwxyz";
+    const char nums[] = "0123456789";
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    const struct lfs_file_config filecfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', "abcd", 4},
+        },
+    };
+    lfs_file_opencfg(&lfs, &file, "open_me",
+            LFS_O_CREAT | LFS_O_WRONLY, &filecfg) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &file, &alphas[j % 26], 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // open reader/snapshot
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_t reader;
+    const struct lfs_file_config readercfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_t snapshot;
+    const struct lfs_file_config snapshotcfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    lfs_file_opencfg(&lfs, &snapshot, "open_me",
+            LFS_O_RDWR | LFS_O_SNAPSHOT, &snapshotcfg) => 0;
+
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE/2; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    assert(memcmp(snapshotcfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &snapshot, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    // modify snapshot
+    lfs_file_rewind(&lfs, &snapshot) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &snapshot, &nums[j % 10], 1) => 1;
+    }
+    memcpy(snapshotcfg.attrs[0].buffer, "0123", 4);
+
+    lfs_file_rewind(&lfs, &snapshot) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &snapshot, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+
+    lfs_file_sync(&lfs, &snapshot) => 0;
+
+    // reader should not change
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = SIZE/2; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    // snapshot should changed
+    assert(memcmp(snapshotcfg.attrs[0].buffer, "0123", 4) == 0);
+    lfs_file_rewind(&lfs, &snapshot) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &snapshot, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_file_close(&lfs, &snapshot) => 0;
+
+    // disk should not change
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # temporary files
+define.SIZE = [10, 100, 1000, 10000]
+define.TMP_PATH = 'range(4)'
+code = '''
+    const char alphas[] = "abcdefghijklmnopqrstuvwxyz";
+    const char nums[] = "0123456789";
+    const char caps[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    const struct lfs_file_config filecfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', "abcd", 4},
+        },
+    };
+    lfs_file_opencfg(&lfs, &file, "open_me",
+            LFS_O_CREAT | LFS_O_WRONLY, &filecfg) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &file, &alphas[j % 26], 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_file_opencfg(&lfs, &file, "dont_open_me",
+            LFS_O_CREAT | LFS_O_WRONLY, &filecfg) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &file, &alphas[j % 26], 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // open reader/writer/temp
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_t reader;
+    const struct lfs_file_config readercfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_t writer;
+    const struct lfs_file_config writercfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_t tmp;
+    const struct lfs_file_config tmpcfg = {
+        .attr_count = 1,
+        .attrs = (struct lfs_attr[]){
+            {'A', &(uint8_t[4]){0}, 4}
+        },
+    };
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    lfs_file_opencfg(&lfs, &writer, "open_me",
+            LFS_O_WRONLY, &writercfg) => 0;
+    const char *tmp_paths[] = {NULL, "/", "/tmp", "/open_me.tmp"};
+    lfs_file_opencfg(&lfs, &tmp, tmp_paths[TMP_PATH],
+            LFS_O_RDWR | LFS_O_CREAT | LFS_O_SNAPSHOT, &tmpcfg) => 0;
+
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE/3; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    assert(memcmp(tmpcfg.attrs[0].buffer, "\0\0\0\0", 4) == 0);
+    assert(lfs_file_size(&lfs, &tmp) == 0);
+
+    // write to tmp
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &tmp, &nums[j % 10], 1) => 1;
+    }
+    memcpy(tmpcfg.attrs[0].buffer, "0123", 4);
+
+    lfs_file_rewind(&lfs, &tmp) => 0;
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &tmp, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+
+    lfs_file_sync(&lfs, &tmp) => 0;
+
+    // reader should not change
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = SIZE/3; j < 2*SIZE/3; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+
+    // tmp should change
+    assert(memcmp(tmpcfg.attrs[0].buffer, "0123", 4) == 0);
+    lfs_file_rewind(&lfs, &tmp) => 0;
+    for (int j = 0; j < SIZE/2; j++) {
+        lfs_file_read(&lfs, &tmp, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+
+    // write to file
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_write(&lfs, &writer, &caps[j % 26], 1) => 1;
+    }
+    memcpy(writercfg.attrs[0].buffer, "ABCD", 4);
+    lfs_file_sync(&lfs, &writer) => 0;
+
+    // reader should change
+    assert(memcmp(readercfg.attrs[0].buffer, "ABCD", 4) == 0);
+    for (int j = 2*SIZE/3; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == caps[j % 26]);
+    }
+
+    // tmp should not change
+    assert(memcmp(tmpcfg.attrs[0].buffer, "0123", 4) == 0);
+    for (int j = SIZE/2; j < SIZE; j++) {
+        lfs_file_read(&lfs, &tmp, buffer, 1) => 1;
+        assert(buffer[0] == nums[j % 10]);
+    }
+
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_file_close(&lfs, &writer) => 0;
+    lfs_file_close(&lfs, &tmp) => 0;
+
+    // tmp should not appear on disk
+    lfs_dir_open(&lfs, &dir, "/") => 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);
+    lfs_dir_read(&lfs, &dir, &info) => 1;
+    assert(info.type == LFS_TYPE_REG);
+    assert(strcmp(info.name, "dont_open_me") == 0);
+    lfs_dir_read(&lfs, &dir, &info) => 1;
+    assert(info.type == LFS_TYPE_REG);
+    assert(strcmp(info.name, "open_me") == 0);
+    lfs_dir_read(&lfs, &dir, &info) => 0;
+    lfs_dir_close(&lfs, &dir) => 0;
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "ABCD", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == caps[j % 26]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_file_opencfg(&lfs, &reader, "dont_open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_dir_open(&lfs, &dir, "/") => 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);
+    lfs_dir_read(&lfs, &dir, &info) => 1;
+    assert(info.type == LFS_TYPE_REG);
+    assert(strcmp(info.name, "dont_open_me") == 0);
+    lfs_dir_read(&lfs, &dir, &info) => 1;
+    assert(info.type == LFS_TYPE_REG);
+    assert(strcmp(info.name, "open_me") == 0);
+    lfs_dir_read(&lfs, &dir, &info) => 0;
+    lfs_dir_close(&lfs, &dir) => 0;
+    lfs_file_opencfg(&lfs, &reader, "open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "ABCD", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == caps[j % 26]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_file_opencfg(&lfs, &reader, "dont_open_me",
+            LFS_O_RDONLY, &readercfg) => 0;
+    assert(memcmp(readercfg.attrs[0].buffer, "abcd", 4) == 0);
+    for (int j = 0; j < SIZE; j++) {
+        lfs_file_read(&lfs, &reader, buffer, 1) => 1;
+        assert(buffer[0] == alphas[j % 26]);
+    }
+    lfs_file_close(&lfs, &reader) => 0;
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # test snapshot open errors
+code = '''
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, NULL,
+            LFS_O_RDWR | LFS_O_SNAPSHOT) => LFS_ERR_ISDIR;
+    lfs_file_open(&lfs, &file, "/",
+            LFS_O_RDWR | LFS_O_SNAPSHOT) => LFS_ERR_ISDIR;
+    lfs_file_open(&lfs, &file, "/tmp",
+            LFS_O_RDWR | LFS_O_SNAPSHOT) => LFS_ERR_NOENT;
+    lfs_file_open(&lfs, &file, "/tmp/",
+            LFS_O_RDWR | LFS_O_CREAT | LFS_O_SNAPSHOT) => LFS_ERR_NOENT;
+    lfs_file_open(&lfs, &file, "/tmp/tmp",
+            LFS_O_RDWR | LFS_O_CREAT | LFS_O_SNAPSHOT) => LFS_ERR_NOENT;
+    lfs_unmount(&lfs) => 0;
+'''

tests/test_paths.toml

@@ -95,9 +95,9 @@ code = '''
 
     lfs_mkdir(&lfs, "coffee/../milk") => 0;
     lfs_stat(&lfs, "coffee/../milk", &info) => 0;
-    strcmp(info.name, "milk") => 0;
+    assert(strcmp(info.name, "milk") == 0);
     lfs_stat(&lfs, "milk", &info) => 0;
-    strcmp(info.name, "milk") => 0;
+    assert(strcmp(info.name, "milk") == 0);
     lfs_unmount(&lfs) => 0;
 '''
 
@@ -129,9 +129,9 @@ code = '''
     lfs_mount(&lfs, &cfg) => 0;
     lfs_mkdir(&lfs, ".milk") => 0;
     lfs_stat(&lfs, ".milk", &info) => 0;
-    strcmp(info.name, ".milk") => 0;
+    assert(strcmp(info.name, ".milk") == 0);
     lfs_stat(&lfs, "tea/.././.milk", &info) => 0;
-    strcmp(info.name, ".milk") => 0;
+    assert(strcmp(info.name, ".milk") == 0);
     lfs_unmount(&lfs) => 0;
 '''
 
@@ -149,13 +149,13 @@ code = '''
     lfs_mkdir(&lfs, "coffee/coldcoffee") => 0;
 
     lfs_stat(&lfs, "coffee/../../../../../../tea/hottea", &info) => 0;
-    strcmp(info.name, "hottea") => 0;
+    assert(strcmp(info.name, "hottea") == 0);
 
     lfs_mkdir(&lfs, "coffee/../../../../../../milk") => 0;
     lfs_stat(&lfs, "coffee/../../../../../../milk", &info) => 0;
-    strcmp(info.name, "milk") => 0;
+    assert(strcmp(info.name, "milk") == 0);
     lfs_stat(&lfs, "milk", &info) => 0;
-    strcmp(info.name, "milk") => 0;
+    assert(strcmp(info.name, "milk") == 0);
     lfs_unmount(&lfs) => 0;
 '''
 

tests/test_relocations.toml

@@ -148,7 +148,7 @@ code = '''
          # almost every tree operation needs a relocation
 reentrant = true
 # TODO fix this case, caused by non-DAG trees
-#if = '!(DEPTH == 3 && LFS_CACHE_SIZE != 64)'
+if = '!(DEPTH == 3 && LFS_CACHE_SIZE != 64)'
 define = [
     {FILES=6,  DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
     {FILES=26, DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
@@ -210,7 +210,7 @@ code = '''
 [[case]] # reentrant testing for relocations, but now with random renames!
 reentrant = true
 # TODO fix this case, caused by non-DAG trees
-#if = '!(DEPTH == 3 && LFS_CACHE_SIZE != 64)'
+if = '!(DEPTH == 3 && LFS_CACHE_SIZE != 64)'
 define = [
     {FILES=6,  DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
     {FILES=26, DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},