Fix assert

Merge pull request #405 from rojer/mfe
Fix -Wmissing-field-initializers
2025-11-01 08:48:31 +01:00 · 2020-08-18 17:36:14 -04:00 · 2020-04-09 05:42:46 -05:00 · 2020-04-06 19:51:19 +01:00 · 2020-04-03 02:18:14 +01:00 · 2020-03-31 18:25:13 -05:00
30 changed files with 1623 additions and 999 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -7,4 +7,6 @@
 blocks/
 lfs
 test.c
-tests_/*.toml.*
+tests/*.toml.*
+scripts/__pycache__
+.gdb_history
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,49 +1,70 @@
-# Environment variables
+# environment variables
 env:
  global:
    - CFLAGS=-Werror
+    - MAKEFLAGS=-j

-# Common test script
-script:
+# cache installation dirs
+cache:
+  pip: true
+  directories:
+    - $HOME/.cache/apt
+
+# common installation
+_: &install-common
+  # need toml, also pip3 isn't installed by default?
+  - sudo apt-get install python3 python3-pip
+  - sudo pip3 install toml
+  # setup a ram-backed disk to speed up reentrant tests
+  - mkdir disks
+  - sudo mount -t tmpfs -o size=100m tmpfs disks
+  - export TFLAGS="$TFLAGS --disk=disks/disk"
+
+# test cases
+_: &test-example
  # make sure example can at least compile
-  - sed -n '/``` c/,/```/{/```/d; p;}' README.md > test.c &&
+  - sed -n '/``` c/,/```/{/```/d; p}' README.md > test.c &&
    make all CFLAGS+="
        -Duser_provided_block_device_read=NULL
        -Duser_provided_block_device_prog=NULL
        -Duser_provided_block_device_erase=NULL
        -Duser_provided_block_device_sync=NULL
        -include stdio.h"
+# default tests
+_: &test-default
+  # normal+reentrant tests
+  - make test TFLAGS+="-nrk"
+# common real-life geometries
+_: &test-nor
+  # NOR flash: read/prog = 1 block = 4KiB
+  - make test TFLAGS+="-nrk -DLFS_READ_SIZE=1 -DLFS_BLOCK_SIZE=4096"
+_: &test-emmc
+  # eMMC: read/prog = 512 block = 512
+  - make test TFLAGS+="-nrk -DLFS_READ_SIZE=512 -DLFS_BLOCK_SIZE=512"
+_: &test-nand
+  # NAND flash: read/prog = 4KiB block = 32KiB
+  - make test TFLAGS+="-nrk -DLFS_READ_SIZE=4096 -DLFS_BLOCK_SIZE=\(32*1024\)"
+# other extreme geometries that are useful for testing various corner cases
+_: &test-no-intrinsics
+  - make test TFLAGS+="-nrk -DLFS_NO_INTRINSICS"
+_: &test-no-inline
+  - make test TFLAGS+="-nrk -DLFS_INLINE_MAX=0"
+_: &test-byte-writes
+  - make test TFLAGS+="-nrk -DLFS_READ_SIZE=1 -DLFS_CACHE_SIZE=1"
+_: &test-block-cycles
+  - make test TFLAGS+="-nrk -DLFS_BLOCK_CYCLES=1"
+_: &test-odd-block-count
+  - make test TFLAGS+="-nrk -DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD_SIZE=256"
+_: &test-odd-block-size
+  - make test TFLAGS+="-nrk -DLFS_READ_SIZE=11 -DLFS_BLOCK_SIZE=704"

-  # run tests
-  - make test QUIET=1
-
-  # run tests with a few different configurations
-  - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=1      -DLFS_CACHE_SIZE=4"
-  - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=512    -DLFS_CACHE_SIZE=512 -DLFS_BLOCK_CYCLES=16"
-  - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=8      -DLFS_CACHE_SIZE=16  -DLFS_BLOCK_CYCLES=2"
-  - make test QUIET=1 CFLAGS+="-DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD_SIZE=256"
-
-  - make clean test QUIET=1 CFLAGS+="-DLFS_INLINE_MAX=0"
-  - make clean test QUIET=1 CFLAGS+="-DLFS_EMUBD_ERASE_VALUE=0xff"
-  - make clean test QUIET=1 CFLAGS+="-DLFS_NO_INTRINSICS"
-
-  # additional configurations that don't support all tests (this should be
-  # fixed but at the moment it is what it is)
-  - make test_files QUIET=1
-        CFLAGS+="-DLFS_READ_SIZE=1 -DLFS_BLOCK_SIZE=4096"
-  - make test_files QUIET=1
-        CFLAGS+="-DLFS_READ_SIZE=\(2*1024\) -DLFS_BLOCK_SIZE=\(64*1024\)"
-  - make test_files QUIET=1
-        CFLAGS+="-DLFS_READ_SIZE=\(8*1024\) -DLFS_BLOCK_SIZE=\(64*1024\)"
-  - make test_files QUIET=1
-        CFLAGS+="-DLFS_READ_SIZE=11 -DLFS_BLOCK_SIZE=704"
-
+# report size 
+_: &report-size
  # compile and find the code size with the smallest configuration
-  - make clean size
-        OBJ="$(ls lfs*.o | tr '\n' ' ')"
+  - make -j1 clean size
+        OBJ="$(ls lfs*.c | sed 's/\.c/\.o/' | tr '\n' ' ')"
        CFLAGS+="-DLFS_NO_ASSERT -DLFS_NO_DEBUG -DLFS_NO_WARN -DLFS_NO_ERROR"
        | tee sizes
-
  # update status if we succeeded, compare with master if possible
  - |
    if [ "$TRAVIS_TEST_RESULT" -eq 0 ]
@@ -51,10 +72,10 @@ script:
        CURR=$(tail -n1 sizes | awk '{print $1}')
        PREV=$(curl -u "$GEKY_BOT_STATUSES" https://api.github.com/repos/$TRAVIS_REPO_SLUG/status/master \
            | jq -re "select(.sha != \"$TRAVIS_COMMIT\")
-                | .statuses[] | select(.context == \"$STAGE/$NAME\").description
+                | .statuses[] | select(.context == \"${TRAVIS_BUILD_STAGE_NAME,,}/$NAME\").description
                | capture(\"code size is (?<size>[0-9]+)\").size" \
            || echo 0)
-
+  
        STATUS="Passed, code size is ${CURR}B"
        if [ "$PREV" -ne 0 ]
        then
@@ -62,257 +83,347 @@ script:
        fi
    fi

-# CI matrix
+# stage control
+stages:
+  - name: test
+  - name: deploy
+    if: branch = master AND type = push
+
+# job control
 jobs:
-  include:
-    # native testing
-    - stage: test
-      env:
-        - STAGE=test
-        - NAME=littlefs-x86
+  # native testing
+  - &x86
+    stage: test
+    env:
+      - NAME=littlefs-x86
+    install: *install-common
+    script: [*test-example, *report-size]
+  - {<<: *x86, script: [*test-default,          *report-size]}
+  - {<<: *x86, script: [*test-nor,              *report-size]}
+  - {<<: *x86, script: [*test-emmc,             *report-size]}
+  - {<<: *x86, script: [*test-nand,             *report-size]}
+  - {<<: *x86, script: [*test-no-intrinsics,    *report-size]}
+  - {<<: *x86, script: [*test-no-inline,        *report-size]}
+  - {<<: *x86, script: [*test-byte-writes,      *report-size]}
+  - {<<: *x86, script: [*test-block-cycles,     *report-size]}
+  - {<<: *x86, script: [*test-odd-block-count,  *report-size]}
+  - {<<: *x86, script: [*test-odd-block-size,   *report-size]}

-    # cross-compile with ARM (thumb mode)
-    - stage: test
-      env:
-        - STAGE=test
-        - NAME=littlefs-arm
-        - CC="arm-linux-gnueabi-gcc --static -mthumb"
-        - EXEC="qemu-arm"
-      install:
-        - sudo apt-get install
-              gcc-arm-linux-gnueabi
-              libc6-dev-armel-cross
-              qemu-user
-        - arm-linux-gnueabi-gcc --version
-        - qemu-arm -version
+  # cross-compile with ARM (thumb mode)
+  - &arm
+    stage: test
+    env:
+      - NAME=littlefs-arm
+      - CC="arm-linux-gnueabi-gcc --static -mthumb"
+      - TFLAGS="$TFLAGS --exec=qemu-arm"
+    install:
+      - *install-common
+      - sudo apt-get install
+            gcc-arm-linux-gnueabi
+            libc6-dev-armel-cross
+            qemu-user
+      - arm-linux-gnueabi-gcc --version
+      - qemu-arm -version
+    script: [*test-example, *report-size]
+  - {<<: *arm, script: [*test-default,          *report-size]}
+  - {<<: *arm, script: [*test-nor,              *report-size]}
+  - {<<: *arm, script: [*test-emmc,             *report-size]}
+  - {<<: *arm, script: [*test-nand,             *report-size]}
+  - {<<: *arm, script: [*test-no-intrinsics,    *report-size]}
+  - {<<: *arm, script: [*test-no-inline,        *report-size]}
+  # it just takes way to long to run byte-level writes in qemu,
+  # note this is still tested in the native tests
+  #- {<<: *arm, script: [*test-byte-writes,      *report-size]}
+  - {<<: *arm, script: [*test-block-cycles,     *report-size]}
+  - {<<: *arm, script: [*test-odd-block-count,  *report-size]}
+  - {<<: *arm, script: [*test-odd-block-size,   *report-size]}

-    # cross-compile with PowerPC
-    - stage: test
-      env:
-        - STAGE=test
-        - NAME=littlefs-powerpc
-        - CC="powerpc-linux-gnu-gcc --static"
-        - EXEC="qemu-ppc"
-      install:
-        - sudo apt-get install
-              gcc-powerpc-linux-gnu
-              libc6-dev-powerpc-cross
-              qemu-user
-        - powerpc-linux-gnu-gcc --version
-        - qemu-ppc -version
+  # cross-compile with MIPS
+  - &mips
+    stage: test
+    env:
+      - NAME=littlefs-mips
+      - CC="mips-linux-gnu-gcc --static"
+      - TFLAGS="$TFLAGS --exec=qemu-mips"
+    install:
+      - *install-common
+      - sudo apt-get install
+            gcc-mips-linux-gnu
+            libc6-dev-mips-cross
+            qemu-user
+      - mips-linux-gnu-gcc --version
+      - qemu-mips -version
+    script: [*test-example, *report-size]
+  - {<<: *mips, script: [*test-default,          *report-size]}
+  - {<<: *mips, script: [*test-nor,              *report-size]}
+  - {<<: *mips, script: [*test-emmc,             *report-size]}
+  - {<<: *mips, script: [*test-nand,             *report-size]}
+  - {<<: *mips, script: [*test-no-intrinsics,    *report-size]}
+  - {<<: *mips, script: [*test-no-inline,        *report-size]}
+  # it just takes way to long to run byte-level writes in qemu,
+  # note this is still tested in the native tests
+  #- {<<: *mips, script: [*test-byte-writes,      *report-size]}
+  - {<<: *mips, script: [*test-block-cycles,     *report-size]}
+  - {<<: *mips, script: [*test-odd-block-count,  *report-size]}
+  - {<<: *mips, script: [*test-odd-block-size,   *report-size]}

-    # cross-compile with MIPS
-    - stage: test
-      env:
-        - STAGE=test
-        - NAME=littlefs-mips
-        - CC="mips-linux-gnu-gcc --static"
-        - EXEC="qemu-mips"
-      install:
-        - sudo apt-get install
-              gcc-mips-linux-gnu
-              libc6-dev-mips-cross
-              qemu-user
-        - mips-linux-gnu-gcc --version
-        - qemu-mips -version
+  # cross-compile with PowerPC
+  - &powerpc
+    stage: test
+    env:
+      - NAME=littlefs-powerpc
+      - CC="powerpc-linux-gnu-gcc --static"
+      - TFLAGS="$TFLAGS --exec=qemu-ppc"
+    install:
+      - *install-common
+      - sudo apt-get install
+            gcc-powerpc-linux-gnu
+            libc6-dev-powerpc-cross
+            qemu-user
+      - powerpc-linux-gnu-gcc --version
+      - qemu-ppc -version
+    script: [*test-example, *report-size]
+  - {<<: *powerpc, script: [*test-default,          *report-size]}
+  - {<<: *powerpc, script: [*test-nor,              *report-size]}
+  - {<<: *powerpc, script: [*test-emmc,             *report-size]}
+  - {<<: *powerpc, script: [*test-nand,             *report-size]}
+  - {<<: *powerpc, script: [*test-no-intrinsics,    *report-size]}
+  - {<<: *powerpc, script: [*test-no-inline,        *report-size]}
+  # it just takes way to long to run byte-level writes in qemu,
+  # note this is still tested in the native tests
+  #- {<<: *powerpc, script: [*test-byte-writes,      *report-size]}
+  - {<<: *powerpc, script: [*test-block-cycles,     *report-size]}
+  - {<<: *powerpc, script: [*test-odd-block-count,  *report-size]}
+  - {<<: *powerpc, script: [*test-odd-block-size,   *report-size]}

-    # self-host with littlefs-fuse for fuzz test
-    - stage: test
-      env:
-        - STAGE=test
-        - NAME=littlefs-fuse
-      if: branch !~ -prefix$
-      install:
-        - sudo apt-get install libfuse-dev
-        - git clone --depth 1 https://github.com/geky/littlefs-fuse -b v2
-        - fusermount -V
-        - gcc --version
-      before_script:
-        # setup disk for littlefs-fuse
-        - rm -rf littlefs-fuse/littlefs/*
-        - cp -r $(git ls-tree --name-only HEAD) littlefs-fuse/littlefs
+  # test under valgrind, checking for memory errors
+  - &valgrind
+    stage: test
+    env:
+      - NAME=littlefs-valgrind
+    install:
+      - *install-common
+      - sudo apt-get install valgrind
+      - valgrind --version
+    script:
+      - make test TFLAGS+="-k --valgrind"

-        - mkdir mount
-        - sudo chmod a+rw /dev/loop0
-        - dd if=/dev/zero bs=512 count=4096 of=disk
-        - losetup /dev/loop0 disk
-      script:
-        # self-host test
-        - make -C littlefs-fuse
+  # self-host with littlefs-fuse for fuzz test
+  - stage: test
+    env:
+      - NAME=littlefs-fuse
+    if: branch !~ -prefix$
+    install:
+      - *install-common
+      - sudo apt-get install libfuse-dev
+      - git clone --depth 1 https://github.com/geky/littlefs-fuse -b v2
+      - fusermount -V
+      - gcc --version

-        - littlefs-fuse/lfs --format /dev/loop0
-        - littlefs-fuse/lfs /dev/loop0 mount
+      # setup disk for littlefs-fuse
+      - rm -rf littlefs-fuse/littlefs/*
+      - cp -r $(git ls-tree --name-only HEAD) littlefs-fuse/littlefs

-        - ls mount
-        - mkdir mount/littlefs
-        - cp -r $(git ls-tree --name-only HEAD) mount/littlefs
-        - cd mount/littlefs
-        - stat .
-        - ls -flh
-        - make -B test_dirs test_files QUIET=1
+      - mkdir mount
+      - sudo chmod a+rw /dev/loop0
+      - dd if=/dev/zero bs=512 count=128K of=disk
+      - losetup /dev/loop0 disk
+    script:
+      # self-host test
+      - make -C littlefs-fuse

-    # self-host with littlefs-fuse for fuzz test
-    - stage: test
-      env:
-        - STAGE=test
-        - NAME=littlefs-migration
-      if: branch !~ -prefix$
-      install:
-        - sudo apt-get install libfuse-dev
-        - git clone --depth 1 https://github.com/geky/littlefs-fuse -b v2 v2
-        - git clone --depth 1 https://github.com/geky/littlefs-fuse -b v1 v1
-        - fusermount -V
-        - gcc --version
-      before_script:
-        # setup disk for littlefs-fuse
-        - rm -rf v2/littlefs/*
-        - cp -r $(git ls-tree --name-only HEAD) v2/littlefs
+      - littlefs-fuse/lfs --format /dev/loop0
+      - littlefs-fuse/lfs /dev/loop0 mount

-        - mkdir mount
-        - sudo chmod a+rw /dev/loop0
-        - dd if=/dev/zero bs=512 count=4096 of=disk
-        - losetup /dev/loop0 disk
-      script:
-        # compile v1 and v2
-        - make -C v1
-        - make -C v2
+      - ls mount
+      - mkdir mount/littlefs
+      - cp -r $(git ls-tree --name-only HEAD) mount/littlefs
+      - cd mount/littlefs
+      - stat .
+      - ls -flh
+      - make -B test

-        # run self-host test with v1
-        - v1/lfs --format /dev/loop0
-        - v1/lfs /dev/loop0 mount
+  # test migration using littlefs-fuse
+  - stage: test
+    env:
+      - NAME=littlefs-migration
+    if: branch !~ -prefix$
+    install:
+      - *install-common
+      - sudo apt-get install libfuse-dev
+      - git clone --depth 1 https://github.com/geky/littlefs-fuse -b v2 v2
+      - git clone --depth 1 https://github.com/geky/littlefs-fuse -b v1 v1
+      - fusermount -V
+      - gcc --version

-        - ls mount
-        - mkdir mount/littlefs
-        - cp -r $(git ls-tree --name-only HEAD) mount/littlefs
-        - cd mount/littlefs
-        - stat .
-        - ls -flh
-        - make -B test_dirs test_files QUIET=1
+      # setup disk for littlefs-fuse
+      - rm -rf v2/littlefs/*
+      - cp -r $(git ls-tree --name-only HEAD) v2/littlefs

-        # attempt to migrate
-        - cd ../..
-        - fusermount -u mount
+      - mkdir mount
+      - sudo chmod a+rw /dev/loop0
+      - dd if=/dev/zero bs=512 count=128K of=disk
+      - losetup /dev/loop0 disk
+    script:
+      # compile v1 and v2
+      - make -C v1
+      - make -C v2

-        - v2/lfs --migrate /dev/loop0
-        - v2/lfs /dev/loop0 mount
+      # run self-host test with v1
+      - v1/lfs --format /dev/loop0
+      - v1/lfs /dev/loop0 mount

-        # run self-host test with v2 right where we left off
-        - ls mount
-        - cd mount/littlefs
-        - stat .
-        - ls -flh
-        - make -B test_dirs test_files QUIET=1
+      - ls mount
+      - mkdir mount/littlefs
+      - cp -r $(git ls-tree --name-only HEAD) mount/littlefs
+      - cd mount/littlefs
+      - stat .
+      - ls -flh
+      - make -B test

-    # Automatically create releases
-    - stage: deploy
-      env:
-        - STAGE=deploy
-        - NAME=deploy
-      script:
-        - |
-          bash << 'SCRIPT'
-          set -ev
-          # Find version defined in lfs.h
-          LFS_VERSION=$(grep -ox '#define LFS_VERSION .*' lfs.h | cut -d ' ' -f3)
-          LFS_VERSION_MAJOR=$((0xffff & ($LFS_VERSION >> 16)))
-          LFS_VERSION_MINOR=$((0xffff & ($LFS_VERSION >>  0)))
-          # Grab latests patch from repo tags, default to 0, needs finagling
-          # to get past github's pagination api
-          PREV_URL=https://api.github.com/repos/$TRAVIS_REPO_SLUG/git/refs/tags/v$LFS_VERSION_MAJOR.$LFS_VERSION_MINOR.
-          PREV_URL=$(curl -u "$GEKY_BOT_RELEASES" "$PREV_URL" -I \
-              | sed -n '/^Link/{s/.*<\(.*\)>; rel="last"/\1/;p;q0};$q1' \
-              || echo $PREV_URL)
-          LFS_VERSION_PATCH=$(curl -u "$GEKY_BOT_RELEASES" "$PREV_URL" \
-              | jq 'map(.ref | match("\\bv.*\\..*\\.(.*)$";"g")
-                  .captures[].string | tonumber) | max + 1' \
-              || echo 0)
-          # We have our new version
-          LFS_VERSION="v$LFS_VERSION_MAJOR.$LFS_VERSION_MINOR.$LFS_VERSION_PATCH"
-          echo "VERSION $LFS_VERSION"
-          # Check that we're the most recent commit
-          CURRENT_COMMIT=$(curl -f -u "$GEKY_BOT_RELEASES" \
-              https://api.github.com/repos/$TRAVIS_REPO_SLUG/commits/master \
-              | jq -re '.sha')
-          [ "$TRAVIS_COMMIT" == "$CURRENT_COMMIT" ] || exit 0
-          # Create major branch
-          git branch v$LFS_VERSION_MAJOR HEAD
-          # Create major prefix branch
-          git config user.name "geky bot"
-          git config user.email "bot@geky.net"
-          git fetch https://github.com/$TRAVIS_REPO_SLUG.git \
-              --depth=50 v$LFS_VERSION_MAJOR-prefix || true
-          ./scripts/prefix.py lfs$LFS_VERSION_MAJOR
-          git branch v$LFS_VERSION_MAJOR-prefix $( \
-              git commit-tree $(git write-tree) \
-                  $(git rev-parse --verify -q FETCH_HEAD | sed -e 's/^/-p /') \
-                  -p HEAD \
-                  -m "Generated v$LFS_VERSION_MAJOR prefixes")
-          git reset --hard
-          # Update major version branches (vN and vN-prefix)
-          git push --atomic https://$GEKY_BOT_RELEASES@github.com/$TRAVIS_REPO_SLUG.git \
-              v$LFS_VERSION_MAJOR \
-              v$LFS_VERSION_MAJOR-prefix
-          # Build release notes
-          PREV=$(git tag --sort=-v:refname -l "v*" | head -1)
-          if [ ! -z "$PREV" ]
-          then
-              echo "PREV $PREV"
-              CHANGES=$(git log --oneline $PREV.. --grep='^Merge' --invert-grep)
-              printf "CHANGES\n%s\n\n" "$CHANGES"
-          fi
-          case ${GEKY_BOT_DRAFT:-minor} in
-              true)  DRAFT=true ;;
-              minor) DRAFT=$(jq -R 'endswith(".0")' <<< "$LFS_VERSION") ;;
-              false) DRAFT=false ;;
-          esac
-          # Create the release and patch version tag (vN.N.N)
-          curl -f -u "$GEKY_BOT_RELEASES" -X POST \
-              https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases \
-              -d "{
-                  \"tag_name\": \"$LFS_VERSION\",
-                  \"name\": \"${LFS_VERSION%.0}\",
-                  \"target_commitish\": \"$TRAVIS_COMMIT\",
-                  \"draft\": $DRAFT,
-                  \"body\": $(jq -sR '.' <<< "$CHANGES")
-              }" #"
-          SCRIPT
+      # attempt to migrate
+      - cd ../..
+      - fusermount -u mount

-# Manage statuses
+      - v2/lfs --migrate /dev/loop0
+      - v2/lfs /dev/loop0 mount
+
+      # run self-host test with v2 right where we left off
+      - ls mount
+      - cd mount/littlefs
+      - stat .
+      - ls -flh
+      - make -B test
+
+  # automatically create releases
+  - stage: deploy
+    env:
+      - NAME=deploy
+    script:
+      - |
+        bash << 'SCRIPT'
+        set -ev
+        # Find version defined in lfs.h
+        LFS_VERSION=$(grep -ox '#define LFS_VERSION .*' lfs.h | cut -d ' ' -f3)
+        LFS_VERSION_MAJOR=$((0xffff & ($LFS_VERSION >> 16)))
+        LFS_VERSION_MINOR=$((0xffff & ($LFS_VERSION >>  0)))
+        # Grab latests patch from repo tags, default to 0, needs finagling
+        # to get past github's pagination api
+        PREV_URL=https://api.github.com/repos/$TRAVIS_REPO_SLUG/git/refs/tags/v$LFS_VERSION_MAJOR.$LFS_VERSION_MINOR.
+        PREV_URL=$(curl -u "$GEKY_BOT_RELEASES" "$PREV_URL" -I \
+            | sed -n '/^Link/{s/.*<\(.*\)>; rel="last"/\1/;p;q0};$q1' \
+            || echo $PREV_URL)
+        LFS_VERSION_PATCH=$(curl -u "$GEKY_BOT_RELEASES" "$PREV_URL" \
+            | jq 'map(.ref | match("\\bv.*\\..*\\.(.*)$";"g")
+                .captures[].string | tonumber) | max + 1' \
+            || echo 0)
+        # We have our new version
+        LFS_VERSION="v$LFS_VERSION_MAJOR.$LFS_VERSION_MINOR.$LFS_VERSION_PATCH"
+        echo "VERSION $LFS_VERSION"
+        # Check that we're the most recent commit
+        CURRENT_COMMIT=$(curl -f -u "$GEKY_BOT_RELEASES" \
+            https://api.github.com/repos/$TRAVIS_REPO_SLUG/commits/master \
+            | jq -re '.sha')
+        [ "$TRAVIS_COMMIT" == "$CURRENT_COMMIT" ] || exit 0
+        # Create major branch
+        git branch v$LFS_VERSION_MAJOR HEAD
+        # Create major prefix branch
+        git config user.name "geky bot"
+        git config user.email "bot@geky.net"
+        git fetch https://github.com/$TRAVIS_REPO_SLUG.git \
+            --depth=50 v$LFS_VERSION_MAJOR-prefix || true
+        ./scripts/prefix.py lfs$LFS_VERSION_MAJOR
+        git branch v$LFS_VERSION_MAJOR-prefix $( \
+            git commit-tree $(git write-tree) \
+                $(git rev-parse --verify -q FETCH_HEAD | sed -e 's/^/-p /') \
+                -p HEAD \
+                -m "Generated v$LFS_VERSION_MAJOR prefixes")
+        git reset --hard
+        # Update major version branches (vN and vN-prefix)
+        git push --atomic https://$GEKY_BOT_RELEASES@github.com/$TRAVIS_REPO_SLUG.git \
+            v$LFS_VERSION_MAJOR \
+            v$LFS_VERSION_MAJOR-prefix
+        # Build release notes
+        PREV=$(git tag --sort=-v:refname -l "v*" | head -1)
+        if [ ! -z "$PREV" ]
+        then
+            echo "PREV $PREV"
+            CHANGES=$(git log --oneline $PREV.. --grep='^Merge' --invert-grep)
+            printf "CHANGES\n%s\n\n" "$CHANGES"
+        fi
+        case ${GEKY_BOT_DRAFT:-minor} in
+            true)  DRAFT=true ;;
+            minor) DRAFT=$(jq -R 'endswith(".0")' <<< "$LFS_VERSION") ;;
+            false) DRAFT=false ;;
+        esac
+        # Create the release and patch version tag (vN.N.N)
+        curl -f -u "$GEKY_BOT_RELEASES" -X POST \
+            https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases \
+            -d "{
+                \"tag_name\": \"$LFS_VERSION\",
+                \"name\": \"${LFS_VERSION%.0}\",
+                \"target_commitish\": \"$TRAVIS_COMMIT\",
+                \"draft\": $DRAFT,
+                \"body\": $(jq -sR '.' <<< "$CHANGES")
+            }" #"
+        SCRIPT
+
+# manage statuses
 before_install:
  - |
-    curl -u "$GEKY_BOT_STATUSES" -X POST \
-        https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
-        -d "{
-            \"context\": \"$STAGE/$NAME\",
-            \"state\": \"pending\",
-            \"description\": \"${STATUS:-In progress}\",
-            \"target_url\": \"https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$TRAVIS_JOB_ID\"
-        }"
+    # don't clobber other (not us) failures
+    if ! curl https://api.github.com/repos/$TRAVIS_REPO_SLUG/status/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+        | jq -e ".statuses[] | select(
+            .context == \"${TRAVIS_BUILD_STAGE_NAME,,}/$NAME\" and
+            .state == \"failure\" and
+            (.target_url | endswith(\"$TRAVIS_JOB_NUMBER\") | not))"
+    then
+        curl -u "$GEKY_BOT_STATUSES" -X POST \
+            https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+            -d "{
+                \"context\": \"${TRAVIS_BUILD_STAGE_NAME,,}/$NAME\",
+                \"state\": \"pending\",
+                \"description\": \"${STATUS:-In progress}\",
+                \"target_url\": \"$TRAVIS_JOB_WEB_URL#$TRAVIS_JOB_NUMBER\"
+            }"
+    fi

 after_failure:
  - |
-    curl -u "$GEKY_BOT_STATUSES" -X POST \
-        https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
-        -d "{
-            \"context\": \"$STAGE/$NAME\",
-            \"state\": \"failure\",
-            \"description\": \"${STATUS:-Failed}\",
-            \"target_url\": \"https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$TRAVIS_JOB_ID\"
-        }"
+    # don't clobber other (not us) failures
+    if ! curl https://api.github.com/repos/$TRAVIS_REPO_SLUG/status/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+        | jq -e ".statuses[] | select(
+            .context == \"${TRAVIS_BUILD_STAGE_NAME,,}/$NAME\" and
+            .state == \"failure\" and
+            (.target_url | endswith(\"$TRAVIS_JOB_NUMBER\") | not))"
+    then
+        curl -u "$GEKY_BOT_STATUSES" -X POST \
+            https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+            -d "{
+                \"context\": \"${TRAVIS_BUILD_STAGE_NAME,,}/$NAME\",
+                \"state\": \"failure\",
+                \"description\": \"${STATUS:-Failed}\",
+                \"target_url\": \"$TRAVIS_JOB_WEB_URL#$TRAVIS_JOB_NUMBER\"
+            }"
+    fi

 after_success:
  - |
-    curl -u "$GEKY_BOT_STATUSES" -X POST \
-        https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
-        -d "{
-            \"context\": \"$STAGE/$NAME\",
-            \"state\": \"success\",
-            \"description\": \"${STATUS:-Passed}\",
-            \"target_url\": \"https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$TRAVIS_JOB_ID\"
-        }"
-
-# Job control
-stages:
-    - name: test
-    - name: deploy
-      if: branch = master AND type = push
+    # don't clobber other (not us) failures
+    # only update if we were last job to mark in progress,
+    # this isn't perfect but is probably good enough
+    if ! curl https://api.github.com/repos/$TRAVIS_REPO_SLUG/status/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+        | jq -e ".statuses[] | select(
+            .context == \"${TRAVIS_BUILD_STAGE_NAME,,}/$NAME\" and
+            (.state == \"failure\" or .state == \"pending\") and
+            (.target_url | endswith(\"$TRAVIS_JOB_NUMBER\") | not))"
+    then
+        curl -u "$GEKY_BOT_STATUSES" -X POST \
+            https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+            -d "{
+                \"context\": \"${TRAVIS_BUILD_STAGE_NAME,,}/$NAME\",
+                \"state\": \"success\",
+                \"description\": \"${STATUS:-Passed}\",
+                \"target_url\": \"$TRAVIS_JOB_WEB_URL#$TRAVIS_JOB_NUMBER\"
+            }"
+    fi
--- a/4
+++ b/4
@@ -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
@@ -45,7 +43,7 @@ test:
 	./scripts/test.py $(TFLAGS)
 .SECONDEXPANSION:
 test%: tests/test$$(firstword $$(subst \#, ,%)).toml
-	./scripts/test.py $(TFLAGS) $@
+	./scripts/test.py $@ $(TFLAGS)

 -include $(DEP)

--- a/README.md
+++ b/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.
--- a/SPEC.md
+++ b/SPEC.md
@@ -289,8 +289,8 @@ Layout of the name tag:
 ```
        tag                          data
 [--      32      --][---        variable length        ---]
-[1| 3| 8 | 10 | 10 ][---            (size)             ---]
- ^  ^  ^    ^    ^- size               ^- file name
+[1| 3| 8 | 10 | 10 ][---          (size * 8)           ---]
+ ^  ^  ^    ^    ^- size                   ^- file name
 |  |  |    '------ id
 |  |  '----------- file type
 |  '-------------- type1 (0x0)
@@ -470,8 +470,8 @@ Layout of the inline-struct tag:
 ```
        tag                          data
 [--      32      --][---        variable length        ---]
-[1|- 11 -| 10 | 10 ][---            (size)             ---]
- ^    ^     ^    ^- size               ^- inline data
+[1|- 11 -| 10 | 10 ][---           (size * 8)          ---]
+ ^    ^     ^    ^- size                    ^- inline data
 |    |     '------ id
 |    '------------ type (0x201)
 '----------------- valid bit
@@ -556,8 +556,8 @@ Layout of the user-attr tag:
 ```
        tag                          data
 [--      32      --][---        variable length        ---]
-[1| 3| 8 | 10 | 10 ][---            (size)             ---]
- ^  ^  ^    ^    ^- size               ^- attr data
+[1| 3| 8 | 10 | 10 ][---           (size * 8)          ---]
+ ^  ^  ^    ^    ^- size                    ^- attr data
 |  |  |    '------ id
 |  |  '----------- attr type
 |  '-------------- type1 (0x3)
@@ -764,9 +764,9 @@ Layout of the CRC tag:
 ```
        tag                                    data
 [--      32      --][--      32      --|---        variable length        ---]
-[1| 3| 8 | 10 | 10 ][--      32      --|---            (size)             ---]
- ^  ^  ^    ^    ^            ^- crc                      ^- padding
- |  |  |    |    '- size (12)
+[1| 3| 8 | 10 | 10 ][--      32      --|---        (size * 8 - 32)        ---]
+ ^  ^  ^    ^    ^            ^- crc                             ^- padding
+ |  |  |    |    '- size
 |  |  |    '------ id (0x3ff)
 |  |  '----------- valid state
 |  '-------------- type1 (0x5)
--- a/bd/lfs_filebd.c
+++ b/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;
 }
--- a/bd/lfs_filebd.h
+++ b/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
--- a/bd/lfs_rambd.c
+++ b/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;
 }
--- a/bd/lfs_rambd.h
+++ b/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
--- a/bd/lfs_testbd.c
+++ b/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"}, "
@@ -38,23 +38,23 @@ 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;
            }
        }

        memset(bd->wear, 0, sizeof(lfs_testbd_wear_t) * cfg->block_count);
    }
-    
+
    // create underlying block device
    if (bd->persist) {
        bd->u.file.cfg = (struct lfs_filebd_config){
            .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;

@@ -155,22 +156,22 @@ int lfs_testbd_read(const struct lfs_config *cfg, lfs_block_t block,
    LFS_ASSERT(block < cfg->block_count);

    // block bad?
-    if (bd->cfg->erase_cycles &&
-            bd->cfg->badblock_behavior == LFS_TESTBD_BADBLOCK_NOREAD &&
-            bd->wear[block] >= bd->cfg->erase_cycles) {
-        LFS_TRACE("lfs_testbd_read -> %d", LFS_ERR_CORRUPT);
+    if (bd->cfg->erase_cycles && bd->wear[block] >= bd->cfg->erase_cycles &&
+            bd->cfg->badblock_behavior == LFS_TESTBD_BADBLOCK_READERROR) {
+        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;

@@ -180,17 +181,24 @@ int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
    LFS_ASSERT(block < cfg->block_count);

    // block bad?
-    if (bd->cfg->erase_cycles &&
-            bd->cfg->badblock_behavior == LFS_TESTBD_BADBLOCK_NOPROG &&
-            bd->wear[block] >= bd->cfg->erase_cycles) {
-        LFS_TRACE("lfs_testbd_prog -> %d", LFS_ERR_CORRUPT);
-        return LFS_ERR_CORRUPT;
+    if (bd->cfg->erase_cycles && bd->wear[block] >= bd->cfg->erase_cycles) {
+        if (bd->cfg->badblock_behavior ==
+                LFS_TESTBD_BADBLOCK_PROGERROR) {
+            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_TESTBD_TRACE("lfs_testbd_prog -> %d", 0);
+            return 0;
+        }
    }

    // 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;
    }

@@ -199,18 +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
@@ -219,9 +227,14 @@ int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
    // block bad?
    if (bd->cfg->erase_cycles) {
        if (bd->wear[block] >= bd->cfg->erase_cycles) {
-            if (bd->cfg->badblock_behavior == LFS_TESTBD_BADBLOCK_NOERASE) {
-                LFS_TRACE("lfs_testbd_erase -> %d", LFS_ERR_CORRUPT);
+            if (bd->cfg->badblock_behavior ==
+                    LFS_TESTBD_BADBLOCK_ERASEERROR) {
+                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_TESTBD_TRACE("lfs_testbd_erase -> %d", 0);
+                return 0;
            }
        } else {
            // mark wear
@@ -232,7 +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;
    }

@@ -241,20 +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;
 }

@@ -262,20 +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
@@ -284,6 +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;
 }
--- a/bd/lfs_testbd.h
+++ b/bd/lfs_testbd.h
@@ -19,14 +19,25 @@ extern "C"
 #endif


-// Mode determining how "bad blocks" behave during testing. This
-// simulates some real-world circumstances such as writes not
-// going through (noprog), erases not sticking (noerase), and ECC
-// failures (noread).
+// 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).
+//
+// Not that read-noop is not allowed. Read _must_ return a consistent (but
+// may be arbitrary) value on every read.
 enum lfs_testbd_badblock_behavior {
-    LFS_TESTBD_BADBLOCK_NOPROG  = 0,
-    LFS_TESTBD_BADBLOCK_NOERASE = 1,
-    LFS_TESTBD_BADBLOCK_NOREAD  = 2,
+    LFS_TESTBD_BADBLOCK_PROGERROR,
+    LFS_TESTBD_BADBLOCK_ERASEERROR,
+    LFS_TESTBD_BADBLOCK_READERROR,
+    LFS_TESTBD_BADBLOCK_PROGNOOP,
+    LFS_TESTBD_BADBLOCK_ERASENOOP,
 };

 // Type for measuring wear
@@ -82,7 +93,7 @@ typedef struct lfs_testbd {
 /// Block device API ///

 // Create a test block device using the geometry in lfs_config
-// 
+//
 // Note that filebd is used if a path is provided, if path is NULL
 // testbd will use rambd which can be much faster.
 int lfs_testbd_create(const struct lfs_config *cfg, const char *path);
--- a/lfs.c
+++ b/lfs.c
@@ -29,8 +29,8 @@ static int lfs_bd_read(lfs_t *lfs,
        lfs_block_t block, lfs_off_t off,
        void *buffer, lfs_size_t size) {
    uint8_t *data = buffer;
-    LFS_ASSERT(block != LFS_BLOCK_NULL);
-    if (off+size > lfs->cfg->block_size) {
+    if (block >= lfs->cfg->block_count ||
+            off+size > lfs->cfg->block_size) {
        return LFS_ERR_CORRUPT;
    }

@@ -71,6 +71,21 @@ static int lfs_bd_read(lfs_t *lfs,
            diff = lfs_min(diff, rcache->off-off);
        }

+        if (size >= hint && off % lfs->cfg->read_size == 0 &&
+                size >= lfs->cfg->read_size) {
+            // bypass cache?
+            diff = lfs_aligndown(diff, lfs->cfg->read_size);
+            int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
+            if (err) {
+                return err;
+            }
+
+            data += diff;
+            off += diff;
+            size -= diff;
+            continue;
+        }
+
        // load to cache, first condition can no longer fail
        LFS_ASSERT(block < lfs->cfg->block_count);
        rcache->block = block;
@@ -173,7 +188,7 @@ static int lfs_bd_prog(lfs_t *lfs,
        lfs_block_t block, lfs_off_t off,
        const void *buffer, lfs_size_t size) {
    const uint8_t *data = buffer;
-    LFS_ASSERT(block != LFS_BLOCK_NULL);
+    LFS_ASSERT(block == LFS_BLOCK_INLINE || block < lfs->cfg->block_count);
    LFS_ASSERT(off + size <= lfs->cfg->block_size);

    while (size > 0) {
@@ -269,7 +284,7 @@ typedef int32_t lfs_stag_t;
    ((cond) ? LFS_MKTAG(type, id, size) : LFS_MKTAG(LFS_FROM_NOOP, 0, 0))

 #define LFS_MKTAG_IF_ELSE(cond, type1, id1, size1, type2, id2, size2) \
-    ((cond) ? LFS_MKTAG(type, id, size) : LFS_MKTAG(type2, id2, size2))
+    ((cond) ? LFS_MKTAG(type1, id1, size1) : LFS_MKTAG(type2, id2, size2))

 static inline bool lfs_tag_isvalid(lfs_tag_t tag) {
    return !(tag & 0x80000000);
@@ -414,6 +429,9 @@ static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t dir[2],
        lfs_mdir_t *parent);
 static int lfs_fs_relocate(lfs_t *lfs,
        const lfs_block_t oldpair[2], lfs_block_t newpair[2]);
+int lfs_fs_traverseraw(lfs_t *lfs,
+        int (*cb)(void *data, lfs_block_t block), void *data,
+        bool includeorphans);
 static int lfs_fs_forceconsistency(lfs_t *lfs);
 static int lfs_deinit(lfs_t *lfs);
 #ifdef LFS_MIGRATE
@@ -434,6 +452,19 @@ static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
    return 0;
 }

+static void lfs_alloc_ack(lfs_t *lfs) {
+    lfs->free.ack = lfs->cfg->block_count;
+}
+
+// Invalidate the lookahead buffer. This is done during mounting and
+// failed traversals
+static void lfs_alloc_reset(lfs_t *lfs) {
+    lfs->free.off = lfs->seed % lfs->cfg->block_size;
+    lfs->free.size = 0;
+    lfs->free.i = 0;
+    lfs_alloc_ack(lfs);
+}
+
 static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
    while (true) {
        while (lfs->free.i != lfs->free.size) {
@@ -472,18 +503,14 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {

        // find mask of free blocks from tree
        memset(lfs->free.buffer, 0, lfs->cfg->lookahead_size);
-        int err = lfs_fs_traverse(lfs, lfs_alloc_lookahead, lfs);
+        int err = lfs_fs_traverseraw(lfs, lfs_alloc_lookahead, lfs, true);
        if (err) {
+            lfs_alloc_reset(lfs);
            return err;
        }
    }
 }

-static void lfs_alloc_ack(lfs_t *lfs) {
-    lfs->free.ack = lfs->cfg->block_count;
-}
-
-
 /// Metadata pair and directory operations ///
 static lfs_stag_t lfs_dir_getslice(lfs_t *lfs, const lfs_mdir_t *dir,
        lfs_tag_t gmask, lfs_tag_t gtag,
@@ -711,7 +738,7 @@ static int lfs_dir_traverse(lfs_t *lfs,
            uint16_t fromid = lfs_tag_size(tag);
            uint16_t toid = lfs_tag_id(tag);
            int err = lfs_dir_traverse(lfs,
-                    buffer, 0, LFS_BLOCK_NULL, NULL, 0,
+                    buffer, 0, 0xffffffff, NULL, 0,
                    LFS_MKTAG(0x600, 0x3ff, 0),
                    LFS_MKTAG(LFS_TYPE_STRUCT, 0, 0),
                    fromid, fromid+1, toid-fromid+diff,
@@ -745,6 +772,12 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
    // scanning the entire directory
    lfs_stag_t besttag = -1;

+    // if either block address is invalid we return LFS_ERR_CORRUPT here,
+    // otherwise later writes to the pair could fail
+    if (pair[0] >= lfs->cfg->block_count || pair[1] >= lfs->cfg->block_count) {
+        return LFS_ERR_CORRUPT;
+    }
+
    // find the block with the most recent revision
    uint32_t revs[2] = {0, 0};
    int r = 0;
@@ -771,7 +804,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
    // now scan tags to fetch the actual dir and find possible match
    for (int i = 0; i < 2; i++) {
        lfs_off_t off = 0;
-        lfs_tag_t ptag = LFS_BLOCK_NULL;
+        lfs_tag_t ptag = 0xffffffff;

        uint16_t tempcount = 0;
        lfs_block_t temptail[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
@@ -779,7 +812,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
        lfs_stag_t tempbesttag = besttag;

        dir->rev = lfs_tole32(dir->rev);
-        uint32_t crc = lfs_crc(LFS_BLOCK_NULL, &dir->rev, sizeof(dir->rev));
+        uint32_t crc = lfs_crc(0xffffffff, &dir->rev, sizeof(dir->rev));
        dir->rev = lfs_fromle32(dir->rev);

        while (true) {
@@ -802,11 +835,13 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
            tag = lfs_frombe32(tag) ^ ptag;

            // next commit not yet programmed or we're not in valid range
-            if (!lfs_tag_isvalid(tag) ||
-                    off + lfs_tag_dsize(tag) > lfs->cfg->block_size) {
+            if (!lfs_tag_isvalid(tag)) {
                dir->erased = (lfs_tag_type1(ptag) == LFS_TYPE_CRC &&
                        dir->off % lfs->cfg->prog_size == 0);
                break;
+            } else if (off + lfs_tag_dsize(tag) > lfs->cfg->block_size) {
+                dir->erased = false;
+                break;
            }

            ptag = tag;
@@ -848,7 +883,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
                dir->split = tempsplit;

                // reset crc
-                crc = LFS_BLOCK_NULL;
+                crc = 0xffffffff;
                continue;
            }

@@ -959,7 +994,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
        dir->rev = revs[(r+1)%2];
    }

-    LFS_ERROR("Corrupted dir pair at %"PRIx32" %"PRIx32,
+    LFS_ERROR("Corrupted dir pair at {0x%"PRIx32", 0x%"PRIx32"}",
            dir->pair[0], dir->pair[1]);
    return LFS_ERR_CORRUPT;
 }
@@ -1226,13 +1261,14 @@ static int lfs_dir_commitattr(lfs_t *lfs, struct lfs_commit *commit,
 }

 static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {
+    const lfs_off_t off1 = commit->off;
+    const uint32_t crc1 = commit->crc;
    // align to program units
-    const lfs_off_t off1 = commit->off + sizeof(lfs_tag_t);
-    const lfs_off_t end = lfs_alignup(off1 + sizeof(uint32_t),
+    const lfs_off_t end = lfs_alignup(off1 + 2*sizeof(uint32_t),
            lfs->cfg->prog_size);

    // create crc tags to fill up remainder of commit, note that
-    // padding is not crcd, which lets fetches skip padding but
+    // padding is not crced, which lets fetches skip padding but
    // makes committing a bit more complicated
    while (commit->off < end) {
        lfs_off_t off = commit->off + sizeof(lfs_tag_t);
@@ -1242,7 +1278,7 @@ static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {
        }

        // read erased state from next program unit
-        lfs_tag_t tag = LFS_BLOCK_NULL;
+        lfs_tag_t tag = 0xffffffff;
        int err = lfs_bd_read(lfs,
                NULL, &lfs->rcache, sizeof(tag),
                commit->block, noff, &tag, sizeof(tag));
@@ -1268,7 +1304,7 @@ static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {

        commit->off += sizeof(tag)+lfs_tag_size(tag);
        commit->ptag = tag ^ ((lfs_tag_t)reset << 31);
-        commit->crc = LFS_BLOCK_NULL; // reset crc for next "commit"
+        commit->crc = 0xffffffff; // reset crc for next "commit"
    }

    // flush buffers
@@ -1279,10 +1315,16 @@ static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {

    // successful commit, check checksums to make sure
    lfs_off_t off = commit->begin;
-    lfs_off_t noff = off1;
+    lfs_off_t noff = off1 + sizeof(uint32_t);
    while (off < end) {
-        uint32_t crc = LFS_BLOCK_NULL;
+        uint32_t crc = 0xffffffff;
        for (lfs_off_t i = off; i < noff+sizeof(uint32_t); i++) {
+            // check against written crc, may catch blocks that
+            // become readonly and match our commit size exactly
+            if (i == off1 && crc != crc1) {
+                return LFS_ERR_CORRUPT;
+            }
+
            // leave it up to caching to make this efficient
            uint8_t dat;
            err = lfs_bd_read(lfs,
@@ -1320,6 +1362,9 @@ static int lfs_dir_alloc(lfs_t *lfs, lfs_mdir_t *dir) {
        }
    }

+    // zero for reproducability in case initial block is unreadable
+    dir->rev = 0;
+
    // rather than clobbering one of the blocks we just pretend
    // the revision may be valid
    int err = lfs_bd_read(lfs,
@@ -1335,7 +1380,7 @@ static int lfs_dir_alloc(lfs_t *lfs, lfs_mdir_t *dir) {

    // set defaults
    dir->off = sizeof(dir->rev);
-    dir->etag = LFS_BLOCK_NULL;
+    dir->etag = 0xffffffff;
    dir->count = 0;
    dir->tail[0] = LFS_BLOCK_NULL;
    dir->tail[1] = LFS_BLOCK_NULL;
@@ -1420,16 +1465,16 @@ static int lfs_dir_compact(lfs_t *lfs,
        lfs_mdir_t *dir, const struct lfs_mattr *attrs, int attrcount,
        lfs_mdir_t *source, uint16_t begin, uint16_t end) {
    // save some state in case block is bad
-    const lfs_block_t oldpair[2] = {dir->pair[1], dir->pair[0]};
+    const lfs_block_t oldpair[2] = {dir->pair[0], dir->pair[1]};
    bool relocated = false;
-    bool exhausted = false;
+    bool tired = false;

    // should we split?
    while (end - begin > 1) {
        // find size
        lfs_size_t size = 0;
        int err = lfs_dir_traverse(lfs,
-                source, 0, LFS_BLOCK_NULL, attrs, attrcount,
+                source, 0, 0xffffffff, attrs, attrcount,
                LFS_MKTAG(0x400, 0x3ff, 0),
                LFS_MKTAG(LFS_TYPE_NAME, 0, 0),
                begin, end, -begin,
@@ -1469,8 +1514,14 @@ static int lfs_dir_compact(lfs_t *lfs,

    // increment revision count
    dir->rev += 1;
+    // If our revision count == n * block_cycles, we should force a relocation,
+    // this is how littlefs wear-levels at the metadata-pair level. Note that we
+    // actually use (block_cycles+1)|1, this is to avoid two corner cases:
+    // 1. block_cycles = 1, which would prevent relocations from terminating
+    // 2. block_cycles = 2n, which, due to aliasing, would only ever relocate
+    //    one metadata block in the pair, effectively making this useless
    if (lfs->cfg->block_cycles > 0 &&
-            (dir->rev % (lfs->cfg->block_cycles+1) == 0)) {
+            (dir->rev % ((lfs->cfg->block_cycles+1)|1) == 0)) {
        if (lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0) {
            // oh no! we're writing too much to the superblock,
            // should we expand?
@@ -1506,7 +1557,7 @@ static int lfs_dir_compact(lfs_t *lfs,
 #endif
        } else {
            // we're writing too much, time to relocate
-            exhausted = true;
+            tired = true;
            goto relocate;
        }
    }
@@ -1518,8 +1569,8 @@ static int lfs_dir_compact(lfs_t *lfs,
            struct lfs_commit commit = {
                .block = dir->pair[1],
                .off = 0,
-                .ptag = LFS_BLOCK_NULL,
-                .crc = LFS_BLOCK_NULL,
+                .ptag = 0xffffffff,
+                .crc = 0xffffffff,

                .begin = 0,
                .end = lfs->cfg->block_size - 8,
@@ -1548,7 +1599,7 @@ static int lfs_dir_compact(lfs_t *lfs,

            // traverse the directory, this time writing out all unique tags
            err = lfs_dir_traverse(lfs,
-                    source, 0, LFS_BLOCK_NULL, attrs, attrcount,
+                    source, 0, 0xffffffff, attrs, attrcount,
                    LFS_MKTAG(0x400, 0x3ff, 0),
                    LFS_MKTAG(LFS_TYPE_NAME, 0, 0),
                    begin, end, -begin,
@@ -1630,29 +1681,31 @@ relocate:
        // commit was corrupted, drop caches and prepare to relocate block
        relocated = true;
        lfs_cache_drop(lfs, &lfs->pcache);
-        if (!exhausted) {
-            LFS_DEBUG("Bad block at %"PRIx32, dir->pair[1]);
+        if (!tired) {
+            LFS_DEBUG("Bad block at 0x%"PRIx32, dir->pair[1]);
        }

        // can't relocate superblock, filesystem is now frozen
-        if (lfs_pair_cmp(oldpair, (const lfs_block_t[2]){0, 1}) == 0) {
-            LFS_WARN("Superblock %"PRIx32" has become unwritable", oldpair[1]);
+        if (lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0) {
+            LFS_WARN("Superblock 0x%"PRIx32" has become unwritable",
+                    dir->pair[1]);
            return LFS_ERR_NOSPC;
        }

        // relocate half of pair
        int err = lfs_alloc(lfs, &dir->pair[1]);
-        if (err && (err != LFS_ERR_NOSPC || !exhausted)) {
+        if (err && (err != LFS_ERR_NOSPC || !tired)) {
            return err;
        }

-        exhausted = false;
+        tired = false;
        continue;
    }

    if (relocated) {
        // update references if we relocated
-        LFS_DEBUG("Relocating %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
+        LFS_DEBUG("Relocating {0x%"PRIx32", 0x%"PRIx32"} "
+                    "-> {0x%"PRIx32", 0x%"PRIx32"}",
                oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
        int err = lfs_fs_relocate(lfs, oldpair, dir->pair);
        if (err) {
@@ -1684,6 +1737,7 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
    }

    // calculate changes to the directory
+    lfs_mdir_t olddir = *dir;
    bool hasdelete = false;
    for (int i = 0; i < attrcount; i++) {
        if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_CREATE) {
@@ -1705,11 +1759,16 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
        lfs_mdir_t pdir;
        int err = lfs_fs_pred(lfs, dir->pair, &pdir);
        if (err && err != LFS_ERR_NOENT) {
+            *dir = olddir;
            return err;
        }

        if (err != LFS_ERR_NOENT && pdir.split) {
-            return lfs_dir_drop(lfs, &pdir, dir);
+            err = lfs_dir_drop(lfs, &pdir, dir);
+            if (err) {
+                *dir = olddir;
+                return err;
+            }
        }
    }

@@ -1719,7 +1778,7 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
            .block = dir->pair[0],
            .off = dir->off,
            .ptag = dir->etag,
-            .crc = LFS_BLOCK_NULL,
+            .crc = 0xffffffff,

            .begin = dir->off,
            .end = lfs->cfg->block_size - 8,
@@ -1737,6 +1796,7 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
            if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
                goto compact;
            }
+            *dir = olddir;
            return err;
        }

@@ -1749,6 +1809,7 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
        if (!lfs_gstate_iszero(&delta)) {
            err = lfs_dir_getgstate(lfs, dir, &delta);
            if (err) {
+                *dir = olddir;
                return err;
            }

@@ -1760,6 +1821,7 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
                if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
                    goto compact;
                }
+                *dir = olddir;
                return err;
            }
        }
@@ -1770,6 +1832,7 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
            if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
                goto compact;
            }
+            *dir = olddir;
            return err;
        }

@@ -1788,6 +1851,7 @@ compact:
        int err = lfs_dir_compact(lfs, dir, attrs, attrcount,
                dir, 0, dir->count);
        if (err) {
+            *dir = olddir;
            return err;
        }
    }
@@ -1800,9 +1864,8 @@ compact:
    // we need to copy the pair so they don't get clobbered if we refetch
    // our mdir.
    for (struct lfs_mlist *d = lfs->mlist; d; d = d->next) {
-        if (&d->m != dir && lfs_pair_cmp(d->m.pair, dir->pair) == 0) {
+        if (&d->m != dir && lfs_pair_cmp(d->m.pair, olddir.pair) == 0) {
            d->m = *dir;
-
            for (int i = 0; i < attrcount; i++) {
                if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_DELETE &&
                        d->id == lfs_tag_id(attrs[i].tag)) {
@@ -1825,9 +1888,8 @@ compact:
        }
    }

-    lfs_block_t pair[2] = {dir->pair[0], dir->pair[1]};
    for (struct lfs_mlist *d = lfs->mlist; d; d = d->next) {
-        if (lfs_pair_cmp(d->m.pair, pair) == 0) {
+        if (lfs_pair_cmp(d->m.pair, olddir.pair) == 0) {
            while (d->id >= d->m.count && d->m.split) {
                // we split and id is on tail now
                d->id -= d->m.count;
@@ -2167,7 +2229,6 @@ static int lfs_ctz_find(lfs_t *lfs,
            return err;
        }

-        LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
        current -= 1 << skip;
    }

@@ -2187,7 +2248,6 @@ static int lfs_ctz_extend(lfs_t *lfs,
        if (err) {
            return err;
        }
-        LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);

        {
            err = lfs_bd_erase(lfs, nblock);
@@ -2204,16 +2264,16 @@ static int lfs_ctz_extend(lfs_t *lfs,
                return 0;
            }

-            size -= 1;
-            lfs_off_t index = lfs_ctz_index(lfs, &size);
-            size += 1;
+            lfs_size_t noff = size - 1;
+            lfs_off_t index = lfs_ctz_index(lfs, &noff);
+            noff = noff + 1;

            // just copy out the last block if it is incomplete
-            if (size != lfs->cfg->block_size) {
-                for (lfs_off_t i = 0; i < size; i++) {
+            if (noff != lfs->cfg->block_size) {
+                for (lfs_off_t i = 0; i < noff; i++) {
                    uint8_t data;
                    err = lfs_bd_read(lfs,
-                            NULL, rcache, size-i,
+                            NULL, rcache, noff-i,
                            head, i, &data, 1);
                    if (err) {
                        return err;
@@ -2231,19 +2291,19 @@ static int lfs_ctz_extend(lfs_t *lfs,
                }

                *block = nblock;
-                *off = size;
+                *off = noff;
                return 0;
            }

            // append block
            index += 1;
            lfs_size_t skips = lfs_ctz(index) + 1;
-
+            lfs_block_t nhead = head;
            for (lfs_off_t i = 0; i < skips; i++) {
-                head = lfs_tole32(head);
+                nhead = lfs_tole32(nhead);
                err = lfs_bd_prog(lfs, pcache, rcache, true,
-                        nblock, 4*i, &head, 4);
-                head = lfs_fromle32(head);
+                        nblock, 4*i, &nhead, 4);
+                nhead = lfs_fromle32(nhead);
                if (err) {
                    if (err == LFS_ERR_CORRUPT) {
                        goto relocate;
@@ -2253,15 +2313,13 @@ static int lfs_ctz_extend(lfs_t *lfs,

                if (i != skips-1) {
                    err = lfs_bd_read(lfs,
-                            NULL, rcache, sizeof(head),
-                            head, 4*i, &head, sizeof(head));
-                    head = lfs_fromle32(head);
+                            NULL, rcache, sizeof(nhead),
+                            nhead, 4*i, &nhead, sizeof(nhead));
+                    nhead = lfs_fromle32(nhead);
                    if (err) {
                        return err;
                    }
                }
-
-                LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
            }

            *block = nblock;
@@ -2270,7 +2328,7 @@ static int lfs_ctz_extend(lfs_t *lfs,
        }

 relocate:
-        LFS_DEBUG("Bad block at %"PRIx32, nblock);
+        LFS_DEBUG("Bad block at 0x%"PRIx32, nblock);

        // just clear cache and try a new block
        lfs_cache_drop(lfs, pcache);
@@ -2374,9 +2432,9 @@ int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,

        // get next slot and create entry to remember name
        err = lfs_dir_commit(lfs, &file->m, LFS_MKATTRS(
-                {LFS_MKTAG(LFS_TYPE_CREATE, file->id, 0)},
+                {LFS_MKTAG(LFS_TYPE_CREATE, file->id, 0), NULL},
                {LFS_MKTAG(LFS_TYPE_REG, file->id, nlen), path},
-                {LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0)}));
+                {LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0), NULL}));
        if (err) {
            err = LFS_ERR_NAMETOOLONG;
            goto cleanup;
@@ -2574,7 +2632,7 @@ static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file) {
        return 0;

 relocate:
-        LFS_DEBUG("Bad block at %"PRIx32, nblock);
+        LFS_DEBUG("Bad block at 0x%"PRIx32, nblock);

        // just clear cache and try a new block
        lfs_cache_drop(lfs, &lfs->pcache);
@@ -2651,7 +2709,7 @@ static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
                break;

 relocate:
-                LFS_DEBUG("Bad block at %"PRIx32, file->block);
+                LFS_DEBUG("Bad block at 0x%"PRIx32, file->block);
                err = lfs_file_relocate(lfs, file);
                if (err) {
                    return err;
@@ -2677,66 +2735,57 @@ int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
    LFS_TRACE("lfs_file_sync(%p, %p)", (void*)lfs, (void*)file);
    LFS_ASSERT(file->flags & LFS_F_OPENED);

-    while (true) {
-        int err = lfs_file_flush(lfs, file);
-        if (err) {
-            file->flags |= LFS_F_ERRED;
-            LFS_TRACE("lfs_file_sync -> %d", err);
-            return err;
-        }
-
-        if ((file->flags & LFS_F_DIRTY) &&
-                !(file->flags & LFS_F_ERRED) &&
-                !lfs_pair_isnull(file->m.pair)) {
-            // update dir entry
-            uint16_t type;
-            const void *buffer;
-            lfs_size_t size;
-            struct lfs_ctz ctz;
-            if (file->flags & LFS_F_INLINE) {
-                // inline the whole file
-                type = LFS_TYPE_INLINESTRUCT;
-                buffer = file->cache.buffer;
-                size = file->ctz.size;
-            } else {
-                // update the ctz reference
-                type = LFS_TYPE_CTZSTRUCT;
-                // copy ctz so alloc will work during a relocate
-                ctz = file->ctz;
-                lfs_ctz_tole32(&ctz);
-                buffer = &ctz;
-                size = sizeof(ctz);
-            }
-
-            // commit file data and attributes
-            err = lfs_dir_commit(lfs, &file->m, LFS_MKATTRS(
-                    {LFS_MKTAG(type, file->id, size), buffer},
-                    {LFS_MKTAG(LFS_FROM_USERATTRS, file->id,
-                        file->cfg->attr_count), file->cfg->attrs}));
-            if (err) {
-                if (err == LFS_ERR_NOSPC && (file->flags & LFS_F_INLINE)) {
-                    goto relocate;
-                }
-                file->flags |= LFS_F_ERRED;
-                LFS_TRACE("lfs_file_sync -> %d", err);
-                return err;
-            }
-
-            file->flags &= ~LFS_F_DIRTY;
-        }
-
+    if (file->flags & LFS_F_ERRED) {
+        // it's not safe to do anything if our file errored
        LFS_TRACE("lfs_file_sync -> %d", 0);
        return 0;
+    }

-relocate:
-        // inline file doesn't fit anymore
-        err = lfs_file_outline(lfs, file);
+    int err = lfs_file_flush(lfs, file);
+    if (err) {
+        file->flags |= LFS_F_ERRED;
+        LFS_TRACE("lfs_file_sync -> %d", err);
+        return err;
+    }
+
+    if ((file->flags & LFS_F_DIRTY) &&
+            !lfs_pair_isnull(file->m.pair)) {
+        // update dir entry
+        uint16_t type;
+        const void *buffer;
+        lfs_size_t size;
+        struct lfs_ctz ctz;
+        if (file->flags & LFS_F_INLINE) {
+            // inline the whole file
+            type = LFS_TYPE_INLINESTRUCT;
+            buffer = file->cache.buffer;
+            size = file->ctz.size;
+        } else {
+            // update the ctz reference
+            type = LFS_TYPE_CTZSTRUCT;
+            // copy ctz so alloc will work during a relocate
+            ctz = file->ctz;
+            lfs_ctz_tole32(&ctz);
+            buffer = &ctz;
+            size = sizeof(ctz);
+        }
+
+        // commit file data and attributes
+        err = lfs_dir_commit(lfs, &file->m, LFS_MKATTRS(
+                {LFS_MKTAG(type, file->id, size), buffer},
+                {LFS_MKTAG(LFS_FROM_USERATTRS, file->id,
+                    file->cfg->attr_count), file->cfg->attrs}));
        if (err) {
            file->flags |= LFS_F_ERRED;
            LFS_TRACE("lfs_file_sync -> %d", err);
            return err;
        }
+
+        file->flags &= ~LFS_F_DIRTY;
    }
+
+    LFS_TRACE("lfs_file_sync -> %d", 0);
+    return 0;
 }

 lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
@@ -3151,7 +3200,7 @@ int lfs_remove(lfs_t *lfs, const char *path) {

    // delete the entry
    err = lfs_dir_commit(lfs, &cwd, LFS_MKATTRS(
-            {LFS_MKTAG(LFS_TYPE_DELETE, lfs_tag_id(tag), 0)}));
+            {LFS_MKTAG(LFS_TYPE_DELETE, lfs_tag_id(tag), 0), NULL}));
    if (err) {
        lfs->mlist = dir.next;
        LFS_TRACE("lfs_remove -> %d", err);
@@ -3277,12 +3326,12 @@ int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
    // move over all attributes
    err = lfs_dir_commit(lfs, &newcwd, LFS_MKATTRS(
            {LFS_MKTAG_IF(prevtag != LFS_ERR_NOENT,
-                LFS_TYPE_DELETE, newid, 0)},
-            {LFS_MKTAG(LFS_TYPE_CREATE, newid, 0)},
+                LFS_TYPE_DELETE, newid, 0), NULL},
+            {LFS_MKTAG(LFS_TYPE_CREATE, newid, 0), NULL},
            {LFS_MKTAG(lfs_tag_type3(oldtag), newid, strlen(newpath)), newpath},
            {LFS_MKTAG(LFS_FROM_MOVE, newid, lfs_tag_id(oldtag)), &oldcwd},
            {LFS_MKTAG_IF(samepair,
-                LFS_TYPE_DELETE, newoldid, 0)}));
+                LFS_TYPE_DELETE, newoldid, 0), NULL}));
    if (err) {
        lfs->mlist = prevdir.next;
        LFS_TRACE("lfs_rename -> %d", err);
@@ -3295,7 +3344,7 @@ int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
        // prep gstate and delete move id
        lfs_fs_prepmove(lfs, 0x3ff, NULL);
        err = lfs_dir_commit(lfs, &oldcwd, LFS_MKATTRS(
-                {LFS_MKTAG(LFS_TYPE_DELETE, lfs_tag_id(oldtag), 0)}));
+                {LFS_MKTAG(LFS_TYPE_DELETE, lfs_tag_id(oldtag), 0), NULL}));
        if (err) {
            lfs->mlist = prevdir.next;
            LFS_TRACE("lfs_rename -> %d", err);
@@ -3428,7 +3477,7 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
    LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->cache_size == 0);

    // check that the block size is large enough to fit ctz pointers
-    LFS_ASSERT(4*lfs_npw2(LFS_BLOCK_NULL / (lfs->cfg->block_size-2*4))
+    LFS_ASSERT(4*lfs_npw2(0xffffffff / (lfs->cfg->block_size-2*4))
            <= lfs->cfg->block_size);

    // block_cycles = 0 is no longer supported.
@@ -3587,7 +3636,7 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {

        lfs_superblock_tole32(&superblock);
        err = lfs_dir_commit(lfs, &root, LFS_MKATTRS(
-                {LFS_MKTAG(LFS_TYPE_CREATE, 0, 0)},
+                {LFS_MKTAG(LFS_TYPE_CREATE, 0, 0), NULL},
                {LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, 8), "littlefs"},
                {LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
                    &superblock}));
@@ -3641,7 +3690,15 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {

    // scan directory blocks for superblock and any global updates
    lfs_mdir_t dir = {.tail = {0, 1}};
+    lfs_block_t cycle = 0;
    while (!lfs_pair_isnull(dir.tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            err = LFS_ERR_CORRUPT;
+            goto cleanup;
+        }
+        cycle += 1;
+
        // fetch next block in tail list
        lfs_stag_t tag = lfs_dir_fetchmatch(lfs, &dir, dir.tail,
                LFS_MKTAG(0x7ff, 0x3ff, 0),
@@ -3676,7 +3733,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
            uint16_t minor_version = (0xffff & (superblock.version >>  0));
            if ((major_version != LFS_DISK_VERSION_MAJOR ||
                 minor_version > LFS_DISK_VERSION_MINOR)) {
-                LFS_ERROR("Invalid version %"PRIu16".%"PRIu16,
+                LFS_ERROR("Invalid version v%"PRIu16".%"PRIu16,
                        major_version, minor_version);
                err = LFS_ERR_INVAL;
                goto cleanup;
@@ -3732,7 +3789,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {

    // update littlefs with gstate
    if (!lfs_gstate_iszero(&lfs->gstate)) {
-        LFS_DEBUG("Found pending gstate %08"PRIx32" %08"PRIx32" %08"PRIx32,
+        LFS_DEBUG("Found pending gstate 0x%08"PRIx32"%08"PRIx32"%08"PRIx32,
                lfs->gstate.tag,
                lfs->gstate.pair[0],
                lfs->gstate.pair[1]);
@@ -3741,10 +3798,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
    lfs->gdisk = lfs->gstate;

    // setup free lookahead
-    lfs->free.off = lfs->seed % lfs->cfg->block_size;
-    lfs->free.size = 0;
-    lfs->free.i = 0;
-    lfs_alloc_ack(lfs);
+    lfs_alloc_reset(lfs);

    LFS_TRACE("lfs_mount -> %d", 0);
    return 0;
@@ -3764,10 +3818,9 @@ int lfs_unmount(lfs_t *lfs) {


 /// Filesystem filesystem operations ///
-int lfs_fs_traverse(lfs_t *lfs,
-        int (*cb)(void *data, lfs_block_t block), void *data) {
-    LFS_TRACE("lfs_fs_traverse(%p, %p, %p)",
-            (void*)lfs, (void*)(uintptr_t)cb, data);
+int lfs_fs_traverseraw(lfs_t *lfs,
+        int (*cb)(void *data, lfs_block_t block), void *data,
+        bool includeorphans) {
    // iterate over metadata pairs
    lfs_mdir_t dir = {.tail = {0, 1}};

@@ -3776,7 +3829,6 @@ int lfs_fs_traverse(lfs_t *lfs,
    if (lfs->lfs1) {
        int err = lfs1_traverse(lfs, cb, data);
        if (err) {
-            LFS_TRACE("lfs_fs_traverse -> %d", err);
            return err;
        }

@@ -3785,11 +3837,17 @@ int lfs_fs_traverse(lfs_t *lfs,
    }
 #endif

+    lfs_block_t cycle = 0;
    while (!lfs_pair_isnull(dir.tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            return LFS_ERR_CORRUPT;
+        }
+        cycle += 1;
+
        for (int i = 0; i < 2; i++) {
            int err = cb(data, dir.tail[i]);
            if (err) {
-                LFS_TRACE("lfs_fs_traverse -> %d", err);
                return err;
            }
        }
@@ -3797,7 +3855,6 @@ int lfs_fs_traverse(lfs_t *lfs,
        // iterate through ids in directory
        int err = lfs_dir_fetch(lfs, &dir, dir.tail);
        if (err) {
-            LFS_TRACE("lfs_fs_traverse -> %d", err);
            return err;
        }

@@ -3809,7 +3866,6 @@ int lfs_fs_traverse(lfs_t *lfs,
                if (tag == LFS_ERR_NOENT) {
                    continue;
                }
-                LFS_TRACE("lfs_fs_traverse -> %"PRId32, tag);
                return tag;
            }
            lfs_ctz_fromle32(&ctz);
@@ -3818,9 +3874,16 @@ int lfs_fs_traverse(lfs_t *lfs,
                err = lfs_ctz_traverse(lfs, NULL, &lfs->rcache,
                        ctz.head, ctz.size, cb, data);
                if (err) {
-                    LFS_TRACE("lfs_fs_traverse -> %d", err);
                    return err;
                }
+            } else if (includeorphans && 
+                    lfs_tag_type3(tag) == LFS_TYPE_DIRSTRUCT) {
+                for (int i = 0; i < 2; i++) {
+                    err = cb(data, (&ctz.head)[i]);
+                    if (err) {
+                        return err;
+                    }
+                }
            }
        }
    }
@@ -3835,7 +3898,6 @@ int lfs_fs_traverse(lfs_t *lfs,
            int err = lfs_ctz_traverse(lfs, &f->cache, &lfs->rcache,
                    f->ctz.head, f->ctz.size, cb, data);
            if (err) {
-                LFS_TRACE("lfs_fs_traverse -> %d", err);
                return err;
            }
        }
@@ -3844,22 +3906,36 @@ int lfs_fs_traverse(lfs_t *lfs,
            int err = lfs_ctz_traverse(lfs, &f->cache, &lfs->rcache,
                    f->block, f->pos, cb, data);
            if (err) {
-                LFS_TRACE("lfs_fs_traverse -> %d", err);
                return err;
            }
        }
    }

-    LFS_TRACE("lfs_fs_traverse -> %d", 0);
    return 0;
 }

+int lfs_fs_traverse(lfs_t *lfs,
+        int (*cb)(void *data, lfs_block_t block), void *data) {
+    LFS_TRACE("lfs_fs_traverse(%p, %p, %p)",
+            (void*)lfs, (void*)(uintptr_t)cb, data);
+    int err = lfs_fs_traverseraw(lfs, cb, data, true);
+    LFS_TRACE("lfs_fs_traverse -> %d", 0);
+    return err;
+}
+
 static int lfs_fs_pred(lfs_t *lfs,
        const lfs_block_t pair[2], lfs_mdir_t *pdir) {
    // iterate over all directory directory entries
    pdir->tail[0] = 0;
    pdir->tail[1] = 1;
+    lfs_block_t cycle = 0;
    while (!lfs_pair_isnull(pdir->tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            return LFS_ERR_CORRUPT;
+        }
+        cycle += 1;
+
        if (lfs_pair_cmp(pdir->tail, pair) == 0) {
            return 0;
        }
@@ -3902,7 +3978,14 @@ static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t pair[2],
    // use fetchmatch with callback to find pairs
    parent->tail[0] = 0;
    parent->tail[1] = 1;
+    lfs_block_t cycle = 0;
    while (!lfs_pair_isnull(parent->tail)) {
+        if (cycle >= lfs->cfg->block_count/2) {
+            // loop detected
+            return LFS_ERR_CORRUPT;
+        }
+        cycle += 1;
+
        lfs_stag_t tag = lfs_dir_fetchmatch(lfs, parent, parent->tail,
                LFS_MKTAG(0x7ff, 0, 0x3ff),
                LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 0, 8),
@@ -3921,8 +4004,6 @@ static int lfs_fs_relocate(lfs_t *lfs,
        const lfs_block_t oldpair[2], lfs_block_t newpair[2]) {
    // update internal root
    if (lfs_pair_cmp(oldpair, lfs->root) == 0) {
-        LFS_DEBUG("Relocating root %"PRIx32" %"PRIx32,
-                newpair[0], newpair[1]);
        lfs->root[0] = newpair[0];
        lfs->root[1] = newpair[1];
    }
@@ -3958,7 +4039,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
        if (lfs_gstate_hasmovehere(&lfs->gstate, parent.pair)) {
            moveid = lfs_tag_id(lfs->gstate.tag);
            LFS_DEBUG("Fixing move while relocating "
-                    "%"PRIx32" %"PRIx32" %"PRIx16"\n",
+                    "{0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16"\n",
                    parent.pair[0], parent.pair[1], moveid);
            lfs_fs_prepmove(lfs, 0x3ff, NULL);
            if (moveid < lfs_tag_id(tag)) {
@@ -3969,7 +4050,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
        lfs_pair_tole32(newpair);
        int err = lfs_dir_commit(lfs, &parent, LFS_MKATTRS(
                {LFS_MKTAG_IF(moveid != 0x3ff,
-                    LFS_TYPE_DELETE, moveid, 0)},
+                    LFS_TYPE_DELETE, moveid, 0), NULL},
                {tag, newpair}));
        lfs_pair_fromle32(newpair);
        if (err) {
@@ -3994,7 +4075,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
        if (lfs_gstate_hasmovehere(&lfs->gstate, parent.pair)) {
            moveid = lfs_tag_id(lfs->gstate.tag);
            LFS_DEBUG("Fixing move while relocating "
-                    "%"PRIx32" %"PRIx32" %"PRIx16"\n",
+                    "{0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16"\n",
                    parent.pair[0], parent.pair[1], moveid);
            lfs_fs_prepmove(lfs, 0x3ff, NULL);
        }
@@ -4003,7 +4084,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
        lfs_pair_tole32(newpair);
        err = lfs_dir_commit(lfs, &parent, LFS_MKATTRS(
                {LFS_MKTAG_IF(moveid != 0x3ff,
-                    LFS_TYPE_DELETE, moveid, 0)},
+                    LFS_TYPE_DELETE, moveid, 0), NULL},
                {LFS_MKTAG(LFS_TYPE_TAIL + parent.split, 0x3ff, 8), newpair}));
        lfs_pair_fromle32(newpair);
        if (err) {
@@ -4035,7 +4116,7 @@ static int lfs_fs_demove(lfs_t *lfs) {
    }

    // Fix bad moves
-    LFS_DEBUG("Fixing move %"PRIx32" %"PRIx32" %"PRIx16,
+    LFS_DEBUG("Fixing move {0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16,
            lfs->gdisk.pair[0],
            lfs->gdisk.pair[1],
            lfs_tag_id(lfs->gdisk.tag));
@@ -4051,7 +4132,7 @@ static int lfs_fs_demove(lfs_t *lfs) {
    uint16_t moveid = lfs_tag_id(lfs->gdisk.tag);
    lfs_fs_prepmove(lfs, 0x3ff, NULL);
    err = lfs_dir_commit(lfs, &movedir, LFS_MKATTRS(
-            {LFS_MKTAG(LFS_TYPE_DELETE, moveid, 0)}));
+            {LFS_MKTAG(LFS_TYPE_DELETE, moveid, 0), NULL}));
    if (err) {
        return err;
    }
@@ -4086,7 +4167,7 @@ static int lfs_fs_deorphan(lfs_t *lfs) {

            if (tag == LFS_ERR_NOENT) {
                // we are an orphan
-                LFS_DEBUG("Fixing orphan %"PRIx32" %"PRIx32,
+                LFS_DEBUG("Fixing orphan {0x%"PRIx32", 0x%"PRIx32"}",
                        pdir.tail[0], pdir.tail[1]);

                err = lfs_dir_drop(lfs, &pdir, &dir);
@@ -4108,8 +4189,8 @@ static int lfs_fs_deorphan(lfs_t *lfs) {

            if (!lfs_pair_sync(pair, pdir.tail)) {
                // we have desynced
-                LFS_DEBUG("Fixing half-orphan "
-                        "%"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
+                LFS_DEBUG("Fixing half-orphan {0x%"PRIx32", 0x%"PRIx32"} "
+                            "-> {0x%"PRIx32", 0x%"PRIx32"}",
                        pdir.tail[0], pdir.tail[1], pair[0], pair[1]);

                lfs_pair_tole32(pair);
@@ -4157,7 +4238,7 @@ static int lfs_fs_size_count(void *p, lfs_block_t block) {
 lfs_ssize_t lfs_fs_size(lfs_t *lfs) {
    LFS_TRACE("lfs_fs_size(%p)", (void*)lfs);
    lfs_size_t size = 0;
-    int err = lfs_fs_traverse(lfs, lfs_fs_size_count, &size);
+    int err = lfs_fs_traverseraw(lfs, lfs_fs_size_count, &size, false);
    if (err) {
        LFS_TRACE("lfs_fs_size -> %d", err);
        return err;
@@ -4345,7 +4426,7 @@ static int lfs1_dir_fetch(lfs_t *lfs,
            continue;
        }

-        uint32_t crc = LFS_BLOCK_NULL;
+        uint32_t crc = 0xffffffff;
        lfs1_dir_tole32(&test);
        lfs1_crc(&crc, &test, sizeof(test));
        lfs1_dir_fromle32(&test);
@@ -4372,7 +4453,7 @@ static int lfs1_dir_fetch(lfs_t *lfs,
    }

    if (!valid) {
-        LFS_ERROR("Corrupted dir pair at %" PRIx32 " %" PRIx32 ,
+        LFS_ERROR("Corrupted dir pair at {0x%"PRIx32", 0x%"PRIx32"}",
                tpair[0], tpair[1]);
        return LFS_ERR_CORRUPT;
    }
@@ -4560,7 +4641,8 @@ static int lfs1_mount(lfs_t *lfs, struct lfs1 *lfs1,
        }

        if (err || memcmp(superblock.d.magic, "littlefs", 8) != 0) {
-            LFS_ERROR("Invalid superblock at %d %d", 0, 1);
+            LFS_ERROR("Invalid superblock at {0x%"PRIx32", 0x%"PRIx32"}",
+                    0, 1);
            err = LFS_ERR_CORRUPT;
            goto cleanup;
        }
@@ -4569,7 +4651,7 @@ static int lfs1_mount(lfs_t *lfs, struct lfs1 *lfs1,
        uint16_t minor_version = (0xffff & (superblock.d.version >>  0));
        if ((major_version != LFS1_DISK_VERSION_MAJOR ||
             minor_version > LFS1_DISK_VERSION_MINOR)) {
-            LFS_ERROR("Invalid version %d.%d", major_version, minor_version);
+            LFS_ERROR("Invalid version v%d.%d", major_version, minor_version);
            err = LFS_ERR_INVAL;
            goto cleanup;
        }
@@ -4735,7 +4817,8 @@ int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg) {

            // Copy over first block to thread into fs. Unfortunately
            // if this fails there is not much we can do.
-            LFS_DEBUG("Migrating %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
+            LFS_DEBUG("Migrating {0x%"PRIx32", 0x%"PRIx32"} "
+                        "-> {0x%"PRIx32", 0x%"PRIx32"}",
                    lfs->root[0], lfs->root[1], dir1.head[0], dir1.head[1]);

            err = lfs_bd_erase(lfs, dir1.head[1]);
@@ -4781,7 +4864,7 @@ int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg) {
        dir2.pair[1] = dir1.pair[1];
        dir2.rev = dir1.d.rev;
        dir2.off = sizeof(dir2.rev);
-        dir2.etag = LFS_BLOCK_NULL;
+        dir2.etag = 0xffffffff;
        dir2.count = 0;
        dir2.tail[0] = lfs->lfs1->root[0];
        dir2.tail[1] = lfs->lfs1->root[1];
--- a/lfs.h
+++ b/lfs.h
@@ -21,7 +21,7 @@ extern "C"
 // Software library version
 // Major (top-nibble), incremented on backwards incompatible changes
 // Minor (bottom-nibble), incremented on feature additions
-#define LFS_VERSION 0x00020001
+#define LFS_VERSION 0x00020002
 #define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
 #define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >>  0))

--- a/lfs_util.h
+++ b/lfs_util.h
@@ -50,31 +50,35 @@ extern "C"

 // Logging functions
 #ifdef LFS_YES_TRACE
-#define LFS_TRACE(fmt, ...) \
-    printf("%s:%d:trace: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_TRACE_(fmt, ...) \
+    printf("%s:%d:trace: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_TRACE(...) LFS_TRACE_(__VA_ARGS__, "")
 #else
-#define LFS_TRACE(fmt, ...)
+#define LFS_TRACE(...)
 #endif

 #ifndef LFS_NO_DEBUG
-#define LFS_DEBUG(fmt, ...) \
-    printf("%s:%d:debug: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_DEBUG_(fmt, ...) \
+    printf("%s:%d:debug: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_DEBUG(...) LFS_DEBUG_(__VA_ARGS__, "")
 #else
-#define LFS_DEBUG(fmt, ...)
+#define LFS_DEBUG(...)
 #endif

 #ifndef LFS_NO_WARN
-#define LFS_WARN(fmt, ...) \
-    printf("%s:%d:warn: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_WARN_(fmt, ...) \
+    printf("%s:%d:warn: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_WARN(...) LFS_WARN_(__VA_ARGS__, "")
 #else
-#define LFS_WARN(fmt, ...)
+#define LFS_WARN(...)
 #endif

 #ifndef LFS_NO_ERROR
-#define LFS_ERROR(fmt, ...) \
-    printf("%s:%d:error: " fmt "\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_ERROR_(fmt, ...) \
+    printf("%s:%d:error: " fmt "%s\n", __FILE__, __LINE__, __VA_ARGS__)
+#define LFS_ERROR(...) LFS_ERROR_(__VA_ARGS__, "")
 #else
-#define LFS_ERROR(fmt, ...)
+#define LFS_ERROR(...)
 #endif

 // Runtime assertions
@@ -107,7 +111,7 @@ static inline uint32_t lfs_alignup(uint32_t a, uint32_t alignment) {
    return lfs_aligndown(a + alignment-1, alignment);
 }

-// Find the next smallest power of 2 less than or equal to a
+// Find the smallest power of 2 greater than or equal to a
 static inline uint32_t lfs_npw2(uint32_t a) {
 #if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
    return 32 - __builtin_clz(a-1);
--- a/scripts/explode_asserts.py
+++ b/scripts/explode_asserts.py
@@ -166,8 +166,8 @@ def mkassert(type, comp, lh, rh, size=None):
        'type': type.lower(), 'TYPE': type.upper(),
        'comp': comp.lower(), 'COMP': comp.upper(),
        'prefix': PREFIX.lower(), 'PREFIX': PREFIX.upper(),
-        'lh': lh.strip(),
-        'rh': rh.strip(),
+        'lh': lh.strip(' '),
+        'rh': rh.strip(' '),
        'size': size,
    }
    if size:
--- a/scripts/readmdir.py
+++ b/scripts/readmdir.py
@@ -2,6 +2,7 @@

 import struct
 import binascii
+import sys
 import itertools as it

 TAG_TYPES = {
@@ -232,8 +233,8 @@ class MetadataPair:

    def __lt__(self, other):
        # corrupt blocks don't count
-        if not self and other:
-            return True
+        if not self or not other:
+            return bool(other)

        # use sequence arithmetic to avoid overflow
        return not ((other.rev - self.rev) & 0x80000000)
@@ -271,37 +272,39 @@ class MetadataPair:

        raise KeyError(gmask, gtag)

-    def _dump_tags(self, tags, truncate=True):
-        sys.stdout.write("%-8s  %-8s  %-13s %4s %4s  %s\n" % (
-            'off', 'tag', 'type', 'id', 'len',
-            'data (truncated)' if truncate else 12*' '+'data'))
+    def _dump_tags(self, tags, f=sys.stdout, truncate=True):
+        f.write("%-8s  %-8s  %-13s %4s %4s" % (
+            'off', 'tag', 'type', 'id', 'len'))
+        if truncate:
+            f.write('  data (truncated)')
+        f.write('\n')

        for tag in tags:
-            sys.stdout.write("%08x: %08x  %-13s %4s %4s" % (
+            f.write("%08x: %08x  %-13s %4s %4s" % (
                tag.off, tag,
                tag.typerepr(), tag.idrepr(), tag.sizerepr()))
            if truncate:
-                sys.stdout.write("  %-23s  %-8s\n" % (
+                f.write("  %-23s  %-8s\n" % (
                    ' '.join('%02x' % c for c in tag.data[:8]),
                    ''.join(c if c >= ' ' and c <= '~' else '.'
                        for c in map(chr, tag.data[:8]))))
            else:
-                sys.stdout.write("\n")
+                f.write("\n")
                for i in range(0, len(tag.data), 16):
-                    sys.stdout.write("%08x: %-47s  %-16s\n" % (
+                    f.write("  %08x: %-47s  %-16s\n" % (
                        tag.off+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]))))

-    def dump_tags(self, truncate=True):
-        self._dump_tags(self.tags, truncate=truncate)
+    def dump_tags(self, f=sys.stdout, truncate=True):
+        self._dump_tags(self.tags, f=f, truncate=truncate)

-    def dump_log(self, truncate=True):
-        self._dump_tags(self.log, truncate=truncate)
+    def dump_log(self, f=sys.stdout, truncate=True):
+        self._dump_tags(self.log, f=f, truncate=truncate)

-    def dump_all(self, truncate=True):
-        self._dump_tags(self.all_, truncate=truncate)
+    def dump_all(self, f=sys.stdout, truncate=True):
+        self._dump_tags(self.all_, f=f, truncate=truncate)

 def main(args):
    blocks = []
@@ -315,6 +318,24 @@ def main(args):

    # find most recent pair
    mdir = MetadataPair(blocks)
+
+    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 '',
+        ' -> {%#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:
@@ -337,10 +358,10 @@ if __name__ == "__main__":
        help="First block address for finding the metadata pair.")
    parser.add_argument('block2', nargs='?', type=lambda x: int(x, 0),
        help="Second block address for finding the metadata pair.")
-    parser.add_argument('-a', '--all', action='store_true',
-        help="Show all tags in log, included tags in corrupted commits.")
    parser.add_argument('-l', '--log', action='store_true',
        help="Show tags in log.")
+    parser.add_argument('-a', '--all', action='store_true',
+        help="Show all tags in log, included tags in corrupted commits.")
    parser.add_argument('-T', '--no-truncate', action='store_true',
-        help="Don't truncate large amounts of data in tags.")
+        help="Don't truncate large amounts of data.")
    sys.exit(main(parser.parse_args()))
--- a/scripts/readtree.py
+++ b/scripts/readtree.py
@@ -7,120 +7,24 @@ import io
 import itertools as it
 from readmdir import Tag, MetadataPair

-def popc(x):
-    return bin(x).count('1')
-
-def ctz(x):
-    return len(bin(x)) - len(bin(x).rstrip('0'))
-
-def dumptags(args, mdir, f):
-    if args.all:
-        tags = mdir.all_
-    elif args.log:
-        tags = mdir.log
-    else:
-        tags = mdir.tags
-
-    for k, tag in enumerate(tags):
-        f.write("tag %08x %s" % (tag, tag.typerepr()))
-        if tag.id != 0x3ff:
-            f.write(" id %d" % tag.id)
-        if tag.size != 0x3ff:
-            f.write(" size %d" % tag.size)
-        if tag.is_('name'):
-            f.write(" name %s" %
-                json.dumps(tag.data.decode('utf8')))
-        if tag.is_('dirstruct'):
-            f.write(" dir {%#x, %#x}" % struct.unpack(
-                '<II', tag.data[:8].ljust(8, b'\xff')))
-        if tag.is_('ctzstruct'):
-            f.write(" ctz {%#x} size %d" % struct.unpack(
-                '<II', tag.data[:8].ljust(8, b'\xff')))
-        if tag.is_('inlinestruct'):
-            f.write(" inline size %d" % tag.size)
-        if tag.is_('gstate'):
-            f.write(" 0x%s" % ''.join('%02x' % c for c in tag.data))
-        if tag.is_('tail'):
-            f.write(" tail {%#x, %#x}" % struct.unpack(
-                '<II', tag.data[:8].ljust(8, b'\xff')))
-        f.write("\n")
-
-        if args.data:
-            for i in range(0, len(tag.data), 16):
-                f.write("  %-47s  %-16s\n" % (
-                    ' '.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]))))
-
-def dumpentries(args, mdir, f):
-    for k, id_ in enumerate(mdir.ids):
-        name = mdir[Tag('name', id_, 0)]
-        struct_ = mdir[Tag('struct', id_, 0)]
-
-        f.write("id %d %s %s" % (
-            id_, name.typerepr(),
-            json.dumps(name.data.decode('utf8'))))
-        if struct_.is_('dirstruct'):
-            f.write(" dir {%#x, %#x}" % struct.unpack(
-                '<II', struct_.data[:8].ljust(8, b'\xff')))
-        if struct_.is_('ctzstruct'):
-            f.write(" ctz {%#x} size %d" % struct.unpack(
-                '<II', struct_.data[:8].ljust(8, b'\xff')))
-        if struct_.is_('inlinestruct'):
-            f.write(" inline size %d" % struct_.size)
-        f.write("\n")
-
-        if args.data and struct_.is_('inlinestruct'):
-            for i in range(0, len(struct_.data), 16):
-                f.write("  %-47s  %-16s\n" % (
-                    ' '.join('%02x' % c for c in struct_.data[i:i+16]),
-                    ''.join(c if c >= ' ' and c <= '~' else '.'
-                        for c in map(chr, struct_.data[i:i+16]))))
-        elif args.data and 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))
-            for i in range(0, min(len(data), 256)
-                    if not args.no_truncate else len(data), 16):
-                f.write("  %-47s  %-16s\n" % (
-                    ' '.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]))))
-
-        for tag in mdir.tags:
-            if tag.id==id_ and tag.is_('userattr'):
-                f.write("id %d %s size %d\n" % (
-                    id_, tag.typerepr(), tag.size))
-
-                if args.data:
-                    for i in range(0, len(tag.data), 16):
-                        f.write("  %-47s  %-16s\n" % (
-                            ' '.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]))))
-
 def main(args):
+    superblock = None
+    gstate = b'\0\0\0\0\0\0\0\0\0\0\0\0'
+    dirs = []
+    mdirs = []
+    corrupted = []
+    cycle = False
    with open(args.disk, 'rb') as f:
-        dirs = []
-        superblock = None
-        gstate = b''
-        mdirs = []
        tail = (args.block1, args.block2)
        hard = False
        while True:
+            for m in it.chain((m for d in dirs for m in d), mdirs):
+                if set(m.blocks) == set(tail):
+                    # cycle detected
+                    cycle = m.blocks
+            if cycle:
+                break
+
            # load mdir
            data = []
            blocks = {}
@@ -129,6 +33,7 @@ def main(args):
                data.append(f.read(args.block_size)
                    .ljust(args.block_size, b'\xff'))
                blocks[id(data[-1])] = block
+
            mdir = MetadataPair(data)
            mdir.blocks = tuple(blocks[id(p.data)] for p in mdir.pair)

@@ -156,6 +61,10 @@ def main(args):
            except KeyError:
                pass

+            # corrupted?
+            if not mdir:
+                corrupted.append(mdir)
+
            # add to directories
            mdirs.append(mdir)
            if mdir.tail is None or not mdir.tail.is_('hardtail'):
@@ -171,7 +80,7 @@ def main(args):
    # find paths
    dirtable = {}
    for dir in dirs:
-        dirtable[tuple(sorted(dir[0].blocks))] = dir
+        dirtable[frozenset(dir[0].blocks)] = dir

    pending = [("/", dirs[0])]
    while pending:
@@ -183,67 +92,72 @@ def main(args):
                        npath = tag.data.decode('utf8')
                        dirstruct = mdir[Tag('dirstruct', tag.id, 0)]
                        nblocks = struct.unpack('<II', dirstruct.data)
-                        nmdir = dirtable[tuple(sorted(nblocks))]
+                        nmdir = dirtable[frozenset(nblocks)]
                        pending.append(((path + '/' + npath), nmdir))
                    except KeyError:
                        pass

        dir[0].path = path.replace('//', '/')

-    # dump tree
-    if not args.superblock and not args.gstate and not args.mdirs:
-        args.superblock = True
-        args.gstate = True
-        args.mdirs = True
+    # print littlefs + version info
+    version = ('?', '?')
+    if superblock:
+        version = tuple(reversed(
+            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 args.superblock and superblock:
-        print("superblock %s v%d.%d" % (
-            json.dumps(superblock[0].data.decode('utf8')),
-            struct.unpack('<H', superblock[1].data[2:2+2])[0],
-            struct.unpack('<H', superblock[1].data[0:0+2])[0]))
-        print(
-            "  block_size %d\n"
-            "  block_count %d\n"
-            "  name_max %d\n"
-            "  file_max %d\n"
-            "  attr_max %d" % struct.unpack(
-                '<IIIII', superblock[1].data[4:4+20].ljust(20, b'\xff')))
+    # print gstate
+    print("gstate 0x%s" % ''.join('%02x' % c for c in gstate))
+    tag = Tag(struct.unpack('<I', gstate[0:4].ljust(4, b'\xff'))[0])
+    blocks = struct.unpack('<II', gstate[4:4+8].ljust(8, b'\xff'))
+    if tag.size or not tag.isvalid:
+        print("  orphans >=%d" % max(tag.size, 1))
+    if tag.type:
+        print("  move dir {%#x, %#x} id %d" % (
+            blocks[0], blocks[1], tag.id))

-    if args.gstate and gstate:
-        print("gstate 0x%s" % ''.join('%02x' % c for c in gstate))
-        tag = Tag(struct.unpack('<I', gstate[0:4].ljust(4, b'\xff'))[0])
-        blocks = struct.unpack('<II', gstate[4:4+8].ljust(8, b'\xff'))
-        if tag.size:
-            print("  orphans %d" % tag.size)
-        if tag.type:
-            print("  move dir {%#x, %#x} id %d" % (
-                blocks[0], blocks[1], tag.id))
+    # print mdir info
+    for i, dir in enumerate(dirs):
+        print("dir %s" % (json.dumps(dir[0].path)
+            if hasattr(dir[0], 'path') else '(orphan)'))

-    if args.mdirs:
-        for i, dir in enumerate(dirs):
-            print("dir %s" % (json.dumps(dir[0].path)
-                if hasattr(dir[0], 'path') else '(orphan)'))
+        for j, mdir in enumerate(dir):
+            print("mdir {%#x, %#x} rev %d (was %d)%s%s" % (
+                mdir.blocks[0], mdir.blocks[1], mdir.rev, mdir.pair[1].rev,
+                ' (corrupted!)' if not mdir else '',
+                ' -> {%#x, %#x}' % struct.unpack('<II', mdir.tail.data)
+                if mdir.tail else ''))

-            for j, mdir in enumerate(dir):
-                print("mdir {%#x, %#x} rev %d%s" % (
-                    mdir.blocks[0], mdir.blocks[1], mdir.rev,
-                    ' (corrupted)' if not mdir else ''))
+            f = io.StringIO()
+            if args.log:
+                mdir.dump_log(f, truncate=not args.no_truncate)
+            elif args.all:
+                mdir.dump_all(f, truncate=not args.no_truncate)
+            else:
+                mdir.dump_tags(f, truncate=not args.no_truncate)

-                f = io.StringIO()
-                if args.tags or args.all or args.log:
-                    dumptags(args, mdir, f)
-                else:
-                    dumpentries(args, mdir, f)
+            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
+                    '|',
+                    line))

-                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
-                        '|',
-                        line))
+    errcode = 0
+    for mdir in corrupted:
+        errcode = errcode or 1
+        print("*** corrupted mdir {%#x, %#x}! ***" % (
+            mdir.blocks[0], mdir.blocks[1]))

-    return 0 if all(mdir for dir in dirs for mdir in dir) else 1
+    if cycle:
+        errcode = errcode or 2
+        print("*** cycle detected {%#x, %#x}! ***" % (
+            cycle[0], cycle[1]))
+
+    return errcode

 if __name__ == "__main__":
    import argparse
@@ -256,24 +170,14 @@ if __name__ == "__main__":
        help="Size of a block in bytes.")
    parser.add_argument('block1', nargs='?', default=0,
        type=lambda x: int(x, 0),
-        help="Optional first block address for finding the root.")
+        help="Optional first block address for finding the superblock.")
    parser.add_argument('block2', nargs='?', default=1,
        type=lambda x: int(x, 0),
-        help="Optional second block address for finding the root.")
-    parser.add_argument('-s', '--superblock', action='store_true',
-        help="Show contents of the superblock.")
-    parser.add_argument('-g', '--gstate', action='store_true',
-        help="Show contents of global-state.")
-    parser.add_argument('-m', '--mdirs', action='store_true',
-        help="Show contents of metadata-pairs/directories.")
-    parser.add_argument('-t', '--tags', action='store_true',
-        help="Show metadata tags instead of reconstructing entries.")
-    parser.add_argument('-a', '--all', action='store_true',
-        help="Show all tags in log, included tags in corrupted commits.")
+        help="Optional second block address for finding the superblock.")
    parser.add_argument('-l', '--log', action='store_true',
        help="Show tags in log.")
-    parser.add_argument('-d', '--data', action='store_true',
-        help="Also show the raw contents of files/attrs/tags.")
+    parser.add_argument('-a', '--all', action='store_true',
+        help="Show all tags in log, included tags in corrupted commits.")
    parser.add_argument('-T', '--no-truncate', action='store_true',
-        help="Don't truncate large amounts of data in files.")
+        help="Show the full contents of files/attrs/tags.")
    sys.exit(main(parser.parse_args()))
--- a/scripts/test.py
+++ b/scripts/test.py
@@ -52,7 +52,7 @@ DEFINES = {
    'LFS_LOOKAHEAD_SIZE': 16,
    'LFS_ERASE_VALUE': 0xff,
    'LFS_ERASE_CYCLES': 0,
-    'LFS_BADBLOCK_BEHAVIOR': 'LFS_TESTBD_BADBLOCK_NOPROG',
+    'LFS_BADBLOCK_BEHAVIOR': 'LFS_TESTBD_BADBLOCK_PROGERROR',
 }
 PROLOGUE = """
    // prologue
@@ -182,27 +182,43 @@ class TestCase:
        elif args.get('no_internal', False) and self.in_ is not None:
            return False
        elif self.if_ is not None:
-            return eval(self.if_, None, self.defines.copy())
+            if_ = self.if_
+            while True:
+                for k, v in sorted(self.defines.items(),
+                        key=lambda x: len(x[0]), reverse=True):
+                    if k in if_:
+                        if_ = if_.replace(k, '(%s)' % v)
+                        break
+                else:
+                    break
+            if_ = (
+                re.sub('(\&\&|\?)', ' and ',
+                re.sub('(\|\||:)', ' or ',
+                re.sub('!(?!=)', ' not ', if_))))
+            return eval(if_)
        else:
            return True

    def test(self, exec=[], persist=False, cycles=None,
-            gdb=False, failure=None, **args):
+            gdb=False, failure=None, disk=None, **args):
        # build command
        cmd = exec + ['./%s.test' % self.suite.path,
            repr(self.caseno), repr(self.permno)]

        # persist disk or keep in RAM for speed?
        if persist:
+            if not disk:
+                disk = self.suite.path + '.disk'
            if persist != 'noerase':
                try:
-                    os.remove(self.suite.path + '.disk')
+                    with open(disk, 'w') as f:
+                        f.truncate(0)
                    if args.get('verbose', False):
-                        print('rm', self.suite.path + '.disk')
+                        print('truncate --size=0', disk)
                except FileNotFoundError:
                    pass

-            cmd.append(self.suite.path + '.disk')
+            cmd.append(disk)

        # simulate power-loss after n cycles?
        if cycles:
@@ -215,7 +231,7 @@ class TestCase:
                ncmd.extend(['-ex', 'r'])
                if failure.assert_:
                    ncmd.extend(['-ex', 'up 2'])
-            elif gdb == 'start':
+            elif gdb == 'main':
                ncmd.extend([
                    '-ex', 'b %s:%d' % (self.suite.path, self.code_lineno),
                    '-ex', 'r'])
@@ -235,33 +251,37 @@ class TestCase:
        mpty = os.fdopen(mpty, 'r', 1)
        stdout = []
        assert_ = None
-        while True:
-            try:
-                line = mpty.readline()
-            except OSError as e:
-                if e.errno == errno.EIO:
-                    break
-                raise
-            stdout.append(line)
-            if args.get('verbose', False):
-                sys.stdout.write(line)
-            # intercept asserts
-            m = re.match(
-                '^{0}([^:]+):(\d+):(?:\d+:)?{0}{1}:{0}(.*)$'
-                .format('(?:\033\[[\d;]*.| )*', 'assert'),
-                line)
-            if m and assert_ is None:
+        try:
+            while True:
                try:
-                    with open(m.group(1)) as f:
-                        lineno = int(m.group(2))
-                        line = next(it.islice(f, lineno-1, None)).strip('\n')
-                    assert_ = {
-                        'path': m.group(1),
-                        'line': line,
-                        'lineno': lineno,
-                        'message': m.group(3)}
-                except:
-                    pass
+                    line = mpty.readline()
+                except OSError as e:
+                    if e.errno == errno.EIO:
+                        break
+                    raise
+                stdout.append(line)
+                if args.get('verbose', False):
+                    sys.stdout.write(line)
+                # intercept asserts
+                m = re.match(
+                    '^{0}([^:]+):(\d+):(?:\d+:)?{0}{1}:{0}(.*)$'
+                    .format('(?:\033\[[\d;]*.| )*', 'assert'),
+                    line)
+                if m and assert_ is None:
+                    try:
+                        with open(m.group(1)) as f:
+                            lineno = int(m.group(2))
+                            line = (next(it.islice(f, lineno-1, None))
+                                .strip('\n'))
+                        assert_ = {
+                            'path': m.group(1),
+                            'line': line,
+                            'lineno': lineno,
+                            'message': m.group(3)}
+                    except:
+                        pass
+        except KeyboardInterrupt:
+            raise TestFailure(self, 1, stdout, None)
        proc.wait()

        # did we pass?
@@ -279,11 +299,17 @@ class ValgrindTestCase(TestCase):
        return not self.leaky and super().shouldtest(**args)

    def test(self, exec=[], **args):
-        exec = exec + [
+        verbose = args.get('verbose', False)
+        uninit = (self.defines.get('LFS_ERASE_VALUE', None) == -1)
+        exec = [
            'valgrind',
            '--leak-check=full',
+            ] + (['--undef-value-errors=no'] if uninit else []) + [
+            ] + (['--track-origins=yes'] if not uninit else []) + [
            '--error-exitcode=4',
-            '-q']
+            '--error-limit=no',
+            ] + (['--num-callers=1'] if not verbose else []) + [
+            '-q'] + exec
        return super().test(exec=exec, **args)

 class ReentrantTestCase(TestCase):
@@ -294,7 +320,7 @@ class ReentrantTestCase(TestCase):
    def shouldtest(self, **args):
        return self.reentrant and super().shouldtest(**args)

-    def test(self, exec=[], persist=False, gdb=False, failure=None, **args):
+    def test(self, persist=False, gdb=False, failure=None, **args):
        for cycles in it.count(1):
            # clear disk first?
            if cycles == 1 and persist != 'noerase':
@@ -360,10 +386,11 @@ class TestSuite:
            # code lineno?
            if 'code' in case:
                case['code_lineno'] = code_linenos.pop()
-            # give our case's config a copy of our "global" config
-            for k, v in config.items():
-                if k not in case:
-                    case[k] = v
+            # merge conditions if necessary
+            if 'if' in config and 'if' in case:
+                case['if'] = '(%s) && (%s)' % (config['if'], case['if'])
+            elif 'if' in config:
+                case['if'] = config['if']
            # initialize test case
            self.cases.append(TestCase(case, filter=filter,
                suite=self, caseno=i+1, lineno=lineno, **args))
@@ -654,6 +681,10 @@ def main(**args):
    if filtered != sum(len(suite.perms) for suite in suites):
        print('filtered down to %d permutations' % filtered)

+    # only requested to build?
+    if args.get('build', False):
+        return 0
+
    print('====== testing ======')
    try:
        for suite in suites:
@@ -678,18 +709,17 @@ def main(**args):
                        perm=perm, path=perm.suite.path, lineno=perm.lineno,
                        returncode=perm.result.returncode or 0))
                if perm.result.stdout:
-                    for line in (perm.result.stdout
-                            if not perm.result.assert_
-                            else perm.result.stdout[:-1]):
+                    if perm.result.assert_:
+                        stdout = perm.result.stdout[:-1]
+                    else:
+                        stdout = perm.result.stdout
+                    for line in stdout[-5:]:
                        sys.stdout.write(line)
                if perm.result.assert_:
                    sys.stdout.write(
                        "\033[01m{path}:{lineno}:\033[01;31massert:\033[m "
                        "{message}\n{line}\n".format(
                            **perm.result.assert_))
-                else:
-                    for line in perm.result.stdout:
-                        sys.stdout.write(line)
                sys.stdout.write('\n')
                failed += 1

@@ -728,7 +758,9 @@ if __name__ == "__main__":
    parser.add_argument('-p', '--persist', choices=['erase', 'noerase'],
        nargs='?', const='erase',
        help="Store disk image in a file.")
-    parser.add_argument('-g', '--gdb', choices=['init', 'start', 'assert'],
+    parser.add_argument('-b', '--build', action='store_true',
+        help="Only build the tests, do not execute.")
+    parser.add_argument('-g', '--gdb', choices=['init', 'main', 'assert'],
        nargs='?', const='assert',
        help="Drop into gdb on test failure.")
    parser.add_argument('--no-internal', action='store_true',
@@ -741,4 +773,6 @@ if __name__ == "__main__":
        help="Run non-leaky tests under valgrind to check for memory leaks.")
    parser.add_argument('-e', '--exec', default=[], type=lambda e: e.split(' '),
        help="Run tests with another executable prefixed on the command line.")
+    parser.add_argument('-d', '--disk',
+        help="Specify a file to use for persistent/reentrant tests.")
    sys.exit(main(**vars(parser.parse_args())))
--- a/tests/test_alloc.toml
+++ b/tests/test_alloc.toml
@@ -1,9 +1,10 @@
 # allocator tests
-# note for these to work there are many constraints on the device geometry
+# note for these to work there are a number constraints on the device geometry
+if = 'LFS_BLOCK_CYCLES == -1'

 [[case]] # parallel allocation test
 define.FILES = 3
-define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-4)) / FILES)'
+define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-6)) / FILES)'
 code = '''
    const char *names[FILES] = {"bacon", "eggs", "pancakes"};
    lfs_file_t files[FILES];
@@ -46,7 +47,7 @@ code = '''

 [[case]] # serial allocation test
 define.FILES = 3
-define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-4)) / FILES)'
+define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-6)) / FILES)'
 code = '''
    const char *names[FILES] = {"bacon", "eggs", "pancakes"};

@@ -85,7 +86,7 @@ code = '''

 [[case]] # parallel allocation reuse test
 define.FILES = 3
-define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-4)) / FILES)'
+define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-6)) / FILES)'
 define.CYCLES = [1, 10]
 code = '''
    const char *names[FILES] = {"bacon", "eggs", "pancakes"};
@@ -140,7 +141,7 @@ code = '''

 [[case]] # serial allocation reuse test
 define.FILES = 3
-define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-4)) / FILES)'
+define.SIZE = '(((LFS_BLOCK_SIZE-8)*(LFS_BLOCK_COUNT-6)) / FILES)'
 define.CYCLES = [1, 10]
 code = '''
    const char *names[FILES] = {"bacon", "eggs", "pancakes"};
@@ -322,6 +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.
@@ -329,7 +414,7 @@ code = '''
 [[case]] # chained dir exhaustion test
 define.LFS_BLOCK_SIZE = 512
 define.LFS_BLOCK_COUNT = 1024
-if = 'LFS_BLOCK_SIZE == 512 and LFS_BLOCK_COUNT == 1024'
+if = 'LFS_BLOCK_SIZE == 512 && LFS_BLOCK_COUNT == 1024'
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
@@ -400,7 +485,7 @@ code = '''
 [[case]] # split dir test
 define.LFS_BLOCK_SIZE = 512
 define.LFS_BLOCK_COUNT = 1024
-if = 'LFS_BLOCK_SIZE == 512 and LFS_BLOCK_COUNT == 1024'
+if = 'LFS_BLOCK_SIZE == 512 && LFS_BLOCK_COUNT == 1024'
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
@@ -445,7 +530,7 @@ code = '''
 [[case]] # outdated lookahead test
 define.LFS_BLOCK_SIZE = 512
 define.LFS_BLOCK_COUNT = 1024
-if = 'LFS_BLOCK_SIZE == 512 and LFS_BLOCK_COUNT == 1024'
+if = 'LFS_BLOCK_SIZE == 512 && LFS_BLOCK_COUNT == 1024'
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
@@ -510,7 +595,7 @@ code = '''
 [[case]] # outdated lookahead and split dir test
 define.LFS_BLOCK_SIZE = 512
 define.LFS_BLOCK_COUNT = 1024
-if = 'LFS_BLOCK_SIZE == 512 and LFS_BLOCK_COUNT == 1024'
+if = 'LFS_BLOCK_SIZE == 512 && LFS_BLOCK_COUNT == 1024'
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
--- a/tests/test_badblocks.toml
+++ b/tests/test_badblocks.toml
@@ -1,6 +1,17 @@
+# bad blocks with block cycles should be tested in test_relocations
+if = 'LFS_BLOCK_CYCLES == -1'
+
 [[case]] # single bad blocks
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
 define.LFS_ERASE_CYCLES = 0xffffffff
-define.LFS_BADBLOCK_BEHAVIOR = 'LFS_TESTBD_BADBLOCK_NOPROG'
+define.LFS_ERASE_VALUE = [0x00, 0xff, -1]
+define.LFS_BADBLOCK_BEHAVIOR = [
+    'LFS_TESTBD_BADBLOCK_PROGERROR',
+    'LFS_TESTBD_BADBLOCK_ERASEERROR',
+    'LFS_TESTBD_BADBLOCK_READERROR',
+    'LFS_TESTBD_BADBLOCK_PROGNOOP',
+    'LFS_TESTBD_BADBLOCK_ERASENOOP',
+]
 define.NAMEMULT = 64
 define.FILEMULT = 1
 code = '''
@@ -64,144 +75,16 @@ code = '''
    }
 '''

-[[case]] # single persistent blocks (can't erase)
-define.LFS_ERASE_CYCLES = 0xffffffff
-define.LFS_BADBLOCK_BEHAVIOR = 'LFS_TESTBD_BADBLOCK_NOERASE'
-define.NAMEMULT = 64
-define.FILEMULT = 1
-code = '''
-    for (lfs_block_t badblock = 2; badblock < LFS_BLOCK_COUNT; badblock++) {
-        lfs_testbd_setwear(&cfg, badblock-1, 0) => 0;
-        lfs_testbd_setwear(&cfg, badblock, 0xffffffff) => 0;
-        
-        lfs_format(&lfs, &cfg) => 0;
-
-        lfs_mount(&lfs, &cfg) => 0;
-        for (int i = 1; i < 10; i++) {
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j] = '0'+i;
-            }
-            buffer[NAMEMULT] = '\0';
-            lfs_mkdir(&lfs, (char*)buffer) => 0;
-
-            buffer[NAMEMULT] = '/';
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j+NAMEMULT+1] = '0'+i;
-            }
-            buffer[2*NAMEMULT+1] = '\0';
-            lfs_file_open(&lfs, &file, (char*)buffer,
-                    LFS_O_WRONLY | LFS_O_CREAT) => 0;
-            
-            size = NAMEMULT;
-            for (int j = 0; j < i*FILEMULT; j++) {
-                lfs_file_write(&lfs, &file, buffer, size) => size;
-            }
-
-            lfs_file_close(&lfs, &file) => 0;
-        }
-        lfs_unmount(&lfs) => 0;
-
-        lfs_mount(&lfs, &cfg) => 0;
-        for (int i = 1; i < 10; i++) {
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j] = '0'+i;
-            }
-            buffer[NAMEMULT] = '\0';
-            lfs_stat(&lfs, (char*)buffer, &info) => 0;
-            info.type => LFS_TYPE_DIR;
-
-            buffer[NAMEMULT] = '/';
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j+NAMEMULT+1] = '0'+i;
-            }
-            buffer[2*NAMEMULT+1] = '\0';
-            lfs_file_open(&lfs, &file, (char*)buffer, LFS_O_RDONLY) => 0;
-            
-            size = NAMEMULT;
-            for (int j = 0; j < i*FILEMULT; j++) {
-                uint8_t rbuffer[1024];
-                lfs_file_read(&lfs, &file, rbuffer, size) => size;
-                memcmp(buffer, rbuffer, size) => 0;
-            }
-
-            lfs_file_close(&lfs, &file) => 0;
-        }
-        lfs_unmount(&lfs) => 0;
-    }
-'''
-
-[[case]] # single unreadable blocks (can't read)
-define.LFS_ERASE_CYCLES = 0xffffffff
-define.LFS_BADBLOCK_BEHAVIOR = 'LFS_TESTBD_BADBLOCK_NOREAD'
-define.NAMEMULT = 64
-define.FILEMULT = 1
-code = '''
-    for (lfs_block_t badblock = 2; badblock < LFS_BLOCK_COUNT/2; badblock++) {
-        lfs_testbd_setwear(&cfg, badblock-1, 0) => 0;
-        lfs_testbd_setwear(&cfg, badblock, 0xffffffff) => 0;
-        
-        lfs_format(&lfs, &cfg) => 0;
-
-        lfs_mount(&lfs, &cfg) => 0;
-        for (int i = 1; i < 10; i++) {
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j] = '0'+i;
-            }
-            buffer[NAMEMULT] = '\0';
-            lfs_mkdir(&lfs, (char*)buffer) => 0;
-
-            buffer[NAMEMULT] = '/';
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j+NAMEMULT+1] = '0'+i;
-            }
-            buffer[2*NAMEMULT+1] = '\0';
-            lfs_file_open(&lfs, &file, (char*)buffer,
-                    LFS_O_WRONLY | LFS_O_CREAT) => 0;
-            
-            size = NAMEMULT;
-            for (int j = 0; j < i*FILEMULT; j++) {
-                lfs_file_write(&lfs, &file, buffer, size) => size;
-            }
-
-            lfs_file_close(&lfs, &file) => 0;
-        }
-        lfs_unmount(&lfs) => 0;
-
-        lfs_mount(&lfs, &cfg) => 0;
-        for (int i = 1; i < 10; i++) {
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j] = '0'+i;
-            }
-            buffer[NAMEMULT] = '\0';
-            lfs_stat(&lfs, (char*)buffer, &info) => 0;
-            info.type => LFS_TYPE_DIR;
-
-            buffer[NAMEMULT] = '/';
-            for (int j = 0; j < NAMEMULT; j++) {
-                buffer[j+NAMEMULT+1] = '0'+i;
-            }
-            buffer[2*NAMEMULT+1] = '\0';
-            lfs_file_open(&lfs, &file, (char*)buffer, LFS_O_RDONLY) => 0;
-            
-            size = NAMEMULT;
-            for (int j = 0; j < i*FILEMULT; j++) {
-                uint8_t rbuffer[1024];
-                lfs_file_read(&lfs, &file, rbuffer, size) => size;
-                memcmp(buffer, rbuffer, size) => 0;
-            }
-
-            lfs_file_close(&lfs, &file) => 0;
-        }
-        lfs_unmount(&lfs) => 0;
-    }
-'''
-
 [[case]] # region corruption (causes cascading failures)
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
 define.LFS_ERASE_CYCLES = 0xffffffff
+define.LFS_ERASE_VALUE = [0x00, 0xff, -1]
 define.LFS_BADBLOCK_BEHAVIOR = [
-    'LFS_TESTBD_BADBLOCK_NOPROG',
-    'LFS_TESTBD_BADBLOCK_NOERASE',
-    'LFS_TESTBD_BADBLOCK_NOREAD',
+    'LFS_TESTBD_BADBLOCK_PROGERROR',
+    'LFS_TESTBD_BADBLOCK_ERASEERROR',
+    'LFS_TESTBD_BADBLOCK_READERROR',
+    'LFS_TESTBD_BADBLOCK_PROGNOOP',
+    'LFS_TESTBD_BADBLOCK_ERASENOOP',
 ]
 define.NAMEMULT = 64
 define.FILEMULT = 1
@@ -266,11 +149,15 @@ code = '''
 '''

 [[case]] # alternating corruption (causes cascading failures)
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
 define.LFS_ERASE_CYCLES = 0xffffffff
+define.LFS_ERASE_VALUE = [0x00, 0xff, -1]
 define.LFS_BADBLOCK_BEHAVIOR = [
-    'LFS_TESTBD_BADBLOCK_NOPROG',
-    'LFS_TESTBD_BADBLOCK_NOERASE',
-    'LFS_TESTBD_BADBLOCK_NOREAD',
+    'LFS_TESTBD_BADBLOCK_PROGERROR',
+    'LFS_TESTBD_BADBLOCK_ERASEERROR',
+    'LFS_TESTBD_BADBLOCK_READERROR',
+    'LFS_TESTBD_BADBLOCK_PROGNOOP',
+    'LFS_TESTBD_BADBLOCK_ERASENOOP',
 ]
 define.NAMEMULT = 64
 define.FILEMULT = 1
@@ -337,10 +224,13 @@ code = '''
 # other corner cases
 [[case]] # bad superblocks (corrupt 1 or 0)
 define.LFS_ERASE_CYCLES = 0xffffffff
+define.LFS_ERASE_VALUE = [0x00, 0xff, -1]
 define.LFS_BADBLOCK_BEHAVIOR = [
-    'LFS_TESTBD_BADBLOCK_NOPROG',
-    'LFS_TESTBD_BADBLOCK_NOERASE',
-    'LFS_TESTBD_BADBLOCK_NOREAD',
+    'LFS_TESTBD_BADBLOCK_PROGERROR',
+    'LFS_TESTBD_BADBLOCK_ERASEERROR',
+    'LFS_TESTBD_BADBLOCK_READERROR',
+    'LFS_TESTBD_BADBLOCK_PROGNOOP',
+    'LFS_TESTBD_BADBLOCK_ERASENOOP',
 ]
 code = '''
    lfs_testbd_setwear(&cfg, 0, 0xffffffff) => 0;
--- a/tests/test_dirs.toml
+++ b/tests/test_dirs.toml
@@ -155,7 +155,7 @@ code = '''
 '''

 [[case]] # reentrant many directory creation/rename/removal
-define.N = [5, 25]
+define.N = [5, 11]
 reentrant = true
 code = '''
    err = lfs_mount(&lfs, &cfg);
--- a/tests/test_entries.toml
+++ b/tests/test_entries.toml
@@ -3,7 +3,7 @@
 # still pass with other inline sizes but wouldn't be testing anything.

 define.LFS_CACHE_SIZE = 512
-if = 'LFS_CACHE_SIZE == 512'
+if = 'LFS_CACHE_SIZE % LFS_PROG_SIZE == 0 && LFS_CACHE_SIZE == 512'

 [[case]] # entry grow test
 code = '''
--- a/tests/test_evil.toml
+++ b/tests/test_evil.toml
@@ -0,0 +1,288 @@
+# Tests for recovering from conditions which shouldn't normally
+# happen during normal operation of littlefs
+
+# invalid pointer tests (outside of block_count)
+
+[[case]] # invalid tail-pointer test
+define.TAIL_TYPE = ['LFS_TYPE_HARDTAIL', 'LFS_TYPE_SOFTTAIL']
+define.INVALSET = [0x3, 0x1, 0x2]
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+
+    // change tail-pointer to invalid pointers
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
+                (lfs_block_t[2]){
+                    (INVALSET & 0x1) ? 0xcccccccc : 0,
+                    (INVALSET & 0x2) ? 0xcccccccc : 0}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''
+
+[[case]] # invalid dir pointer test
+define.INVALSET = [0x3, 0x1, 0x2]
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+    // make a dir
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "dir_here") => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // change the dir pointer to be invalid
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    // make sure id 1 == our directory
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("dir_here")), buffer)
+                => LFS_MKTAG(LFS_TYPE_DIR, 1, strlen("dir_here"));
+    assert(memcmp((char*)buffer, "dir_here", strlen("dir_here")) == 0);
+    // change dir pointer
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, 8),
+                (lfs_block_t[2]){
+                    (INVALSET & 0x1) ? 0xcccccccc : 0,
+                    (INVALSET & 0x2) ? 0xcccccccc : 0}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that accessing our bad dir fails, note there's a number
+    // of ways to access the dir, some can fail, but some don't
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "dir_here", &info) => 0;
+    assert(strcmp(info.name, "dir_here") == 0);
+    assert(info.type == LFS_TYPE_DIR);
+
+    lfs_dir_open(&lfs, &dir, "dir_here") => LFS_ERR_CORRUPT;
+    lfs_stat(&lfs, "dir_here/file_here", &info) => LFS_ERR_CORRUPT;
+    lfs_dir_open(&lfs, &dir, "dir_here/dir_here") => LFS_ERR_CORRUPT;
+    lfs_file_open(&lfs, &file, "dir_here/file_here",
+            LFS_O_RDONLY) => LFS_ERR_CORRUPT;
+    lfs_file_open(&lfs, &file, "dir_here/file_here",
+            LFS_O_WRONLY | LFS_O_CREAT) => LFS_ERR_CORRUPT;
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # invalid file pointer test
+in = "lfs.c"
+define.SIZE = [10, 1000, 100000] # faked file size
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+    // make a file
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, "file_here",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // change the file pointer to be invalid
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    // make sure id 1 == our file
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("file_here")), buffer)
+                => LFS_MKTAG(LFS_TYPE_REG, 1, strlen("file_here"));
+    assert(memcmp((char*)buffer, "file_here", strlen("file_here")) == 0);
+    // change file pointer
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_CTZSTRUCT, 1, sizeof(struct lfs_ctz)),
+                &(struct lfs_ctz){0xcccccccc, lfs_tole32(SIZE)}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that accessing our bad file fails, note there's a number
+    // of ways to access the dir, some can fail, but some don't
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "file_here", &info) => 0;
+    assert(strcmp(info.name, "file_here") == 0);
+    assert(info.type == LFS_TYPE_REG);
+    assert(info.size == SIZE);
+
+    lfs_file_open(&lfs, &file, "file_here", LFS_O_RDONLY) => 0;
+    lfs_file_read(&lfs, &file, buffer, SIZE) => LFS_ERR_CORRUPT;
+    lfs_file_close(&lfs, &file) => 0;
+
+    // any allocs that traverse CTZ must unfortunately must fail
+    if (SIZE > 2*LFS_BLOCK_SIZE) {
+        lfs_mkdir(&lfs, "dir_here") => LFS_ERR_CORRUPT;
+    }
+    lfs_unmount(&lfs) => 0;
+'''
+
+[[case]] # invalid pointer in CTZ skip-list test
+define.SIZE = ['2*LFS_BLOCK_SIZE', '3*LFS_BLOCK_SIZE', '4*LFS_BLOCK_SIZE']
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+    // make a file
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_file_open(&lfs, &file, "file_here",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    for (int i = 0; i < SIZE; i++) {
+        char c = 'c';
+        lfs_file_write(&lfs, &file, &c, 1) => 1;
+    }
+    lfs_file_close(&lfs, &file) => 0;
+    lfs_unmount(&lfs) => 0;
+    // change pointer in CTZ skip-list to be invalid
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    // make sure id 1 == our file and get our CTZ structure
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_NAME, 1, strlen("file_here")), buffer)
+                => LFS_MKTAG(LFS_TYPE_REG, 1, strlen("file_here"));
+    assert(memcmp((char*)buffer, "file_here", strlen("file_here")) == 0);
+    struct lfs_ctz ctz;
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_STRUCT, 1, sizeof(struct lfs_ctz)), &ctz)
+                => LFS_MKTAG(LFS_TYPE_CTZSTRUCT, 1, sizeof(struct lfs_ctz));
+    lfs_ctz_fromle32(&ctz);
+    // rewrite block to contain bad pointer
+    uint8_t bbuffer[LFS_BLOCK_SIZE];
+    cfg.read(&cfg, ctz.head, 0, bbuffer, LFS_BLOCK_SIZE) => 0;
+    uint32_t bad = lfs_tole32(0xcccccccc);
+    memcpy(&bbuffer[0], &bad, sizeof(bad));
+    memcpy(&bbuffer[4], &bad, sizeof(bad));
+    cfg.erase(&cfg, ctz.head) => 0;
+    cfg.prog(&cfg, ctz.head, 0, bbuffer, LFS_BLOCK_SIZE) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that accessing our bad file fails, note there's a number
+    // of ways to access the dir, some can fail, but some don't
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "file_here", &info) => 0;
+    assert(strcmp(info.name, "file_here") == 0);
+    assert(info.type == LFS_TYPE_REG);
+    assert(info.size == SIZE);
+
+    lfs_file_open(&lfs, &file, "file_here", LFS_O_RDONLY) => 0;
+    lfs_file_read(&lfs, &file, buffer, SIZE) => LFS_ERR_CORRUPT;
+    lfs_file_close(&lfs, &file) => 0;
+
+    // any allocs that traverse CTZ must unfortunately must fail
+    if (SIZE > 2*LFS_BLOCK_SIZE) {
+        lfs_mkdir(&lfs, "dir_here") => LFS_ERR_CORRUPT;
+    }
+    lfs_unmount(&lfs) => 0;
+'''
+
+
+[[case]] # invalid gstate pointer
+define.INVALSET = [0x3, 0x1, 0x2]
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+
+    // create an invalid gstate
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_fs_prepmove(&lfs, 1, (lfs_block_t [2]){
+            (INVALSET & 0x1) ? 0xcccccccc : 0,
+            (INVALSET & 0x2) ? 0xcccccccc : 0});
+    lfs_dir_commit(&lfs, &mdir, NULL, 0) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    // mount may not fail, but our first alloc should fail when
+    // we try to fix the gstate
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "should_fail") => LFS_ERR_CORRUPT;
+    lfs_unmount(&lfs) => 0;
+'''
+
+# cycle detection/recovery tests
+
+[[case]] # metadata-pair threaded-list loop test
+in = "lfs.c"
+code = '''
+    // create littlefs
+    lfs_format(&lfs, &cfg) => 0;
+
+    // change tail-pointer to point to ourself
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
+                (lfs_block_t[2]){0, 1}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''
+
+[[case]] # metadata-pair threaded-list 2-length loop test
+in = "lfs.c"
+code = '''
+    // create littlefs with child dir
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "child") => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // find child
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_block_t pair[2];
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x7ff, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair)), pair)
+                => LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair));
+    lfs_pair_fromle32(pair);
+    // change tail-pointer to point to root
+    lfs_dir_fetch(&lfs, &mdir, pair) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8),
+                (lfs_block_t[2]){0, 1}})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''
+
+[[case]] # metadata-pair threaded-list 1-length child loop test
+in = "lfs.c"
+code = '''
+    // create littlefs with child dir
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "child") => 0;
+    lfs_unmount(&lfs) => 0;
+
+    // find child
+    lfs_init(&lfs, &cfg) => 0;
+    lfs_mdir_t mdir;
+    lfs_block_t pair[2];
+    lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
+    lfs_dir_get(&lfs, &mdir,
+            LFS_MKTAG(0x7ff, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair)), pair)
+                => LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 1, sizeof(pair));
+    lfs_pair_fromle32(pair);
+    // change tail-pointer to point to ourself
+    lfs_dir_fetch(&lfs, &mdir, pair) => 0;
+    lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
+            {LFS_MKTAG(LFS_TYPE_HARDTAIL, 0x3ff, 8), pair})) => 0;
+    lfs_deinit(&lfs) => 0;
+
+    // test that mount fails gracefully
+    lfs_mount(&lfs, &cfg) => LFS_ERR_CORRUPT;
+'''
--- a/tests/test_exhaustion.toml
+++ b/tests/test_exhaustion.toml
@@ -1,11 +1,13 @@
 [[case]] # test running a filesystem to exhaustion
 define.LFS_ERASE_CYCLES = 10
-define.LFS_BLOCK_COUNT = 256 # small bd so it runs faster
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
 define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
 define.LFS_BADBLOCK_BEHAVIOR = [
-    'LFS_TESTBD_BADBLOCK_NOPROG',
-    'LFS_TESTBD_BADBLOCK_NOERASE',
-    'LFS_TESTBD_BADBLOCK_NOREAD',
+    'LFS_TESTBD_BADBLOCK_PROGERROR',
+    'LFS_TESTBD_BADBLOCK_ERASEERROR',
+    'LFS_TESTBD_BADBLOCK_READERROR',
+    'LFS_TESTBD_BADBLOCK_PROGNOOP',
+    'LFS_TESTBD_BADBLOCK_ERASENOOP',
 ]
 define.FILES = 10
 code = '''
@@ -31,6 +33,9 @@ code = '''
                lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                assert(res == 1 || res == LFS_ERR_NOSPC);
                if (res == LFS_ERR_NOSPC) {
+                    err = lfs_file_close(&lfs, &file);
+                    assert(err == 0 || err == LFS_ERR_NOSPC);
+                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
            }
@@ -38,9 +43,10 @@ code = '''
            err = lfs_file_close(&lfs, &file);
            assert(err == 0 || err == LFS_ERR_NOSPC);
            if (err == LFS_ERR_NOSPC) {
+                lfs_unmount(&lfs) => 0;
                goto exhausted;
            }
-        }    
+        }

        for (uint32_t i = 0; i < FILES; i++) {
            // check for errors
@@ -57,7 +63,7 @@ code = '''
            }

            lfs_file_close(&lfs, &file) => 0;
-        }    
+        }
        lfs_unmount(&lfs) => 0;

        cycle += 1;
@@ -70,7 +76,7 @@ exhausted:
        // check for errors
        sprintf(path, "roadrunner/test%d", i);
        lfs_stat(&lfs, path, &info) => 0;
-    }    
+    }
    lfs_unmount(&lfs) => 0;

    LFS_WARN("completed %d cycles", cycle);
@@ -79,12 +85,14 @@ exhausted:
 [[case]] # test running a filesystem to exhaustion
         # which also requires expanding superblocks
 define.LFS_ERASE_CYCLES = 10
-define.LFS_BLOCK_COUNT = 256 # small bd so it runs faster
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
 define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
 define.LFS_BADBLOCK_BEHAVIOR = [
-    'LFS_TESTBD_BADBLOCK_NOPROG',
-    'LFS_TESTBD_BADBLOCK_NOERASE',
-    'LFS_TESTBD_BADBLOCK_NOREAD',
+    'LFS_TESTBD_BADBLOCK_PROGERROR',
+    'LFS_TESTBD_BADBLOCK_ERASEERROR',
+    'LFS_TESTBD_BADBLOCK_READERROR',
+    'LFS_TESTBD_BADBLOCK_PROGNOOP',
+    'LFS_TESTBD_BADBLOCK_ERASENOOP',
 ]
 define.FILES = 10
 code = '''
@@ -107,6 +115,9 @@ code = '''
                lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                assert(res == 1 || res == LFS_ERR_NOSPC);
                if (res == LFS_ERR_NOSPC) {
+                    err = lfs_file_close(&lfs, &file);
+                    assert(err == 0 || err == LFS_ERR_NOSPC);
+                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
            }
@@ -114,9 +125,10 @@ code = '''
            err = lfs_file_close(&lfs, &file);
            assert(err == 0 || err == LFS_ERR_NOSPC);
            if (err == LFS_ERR_NOSPC) {
+                lfs_unmount(&lfs) => 0;
                goto exhausted;
            }
-        }    
+        }

        for (uint32_t i = 0; i < FILES; i++) {
            // check for errors
@@ -133,7 +145,7 @@ code = '''
            }

            lfs_file_close(&lfs, &file) => 0;
-        }    
+        }
        lfs_unmount(&lfs) => 0;

        cycle += 1;
@@ -146,7 +158,7 @@ exhausted:
        // check for errors
        sprintf(path, "test%d", i);
        lfs_stat(&lfs, path, &info) => 0;
-    }    
+    }
    lfs_unmount(&lfs) => 0;

    LFS_WARN("completed %d cycles", cycle);
@@ -158,21 +170,11 @@ exhausted:
 # check for.

 [[case]] # wear-level test running a filesystem to exhaustion
-define.LFS_ERASE_CYCLES = 10
-define.LFS_BLOCK_COUNT = 256 # small bd so it runs faster
+define.LFS_ERASE_CYCLES = 20
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
 define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
-define.LFS_BADBLOCK_BEHAVIOR = [
-    'LFS_TESTBD_BADBLOCK_NOPROG',
-    'LFS_TESTBD_BADBLOCK_NOERASE',
-    'LFS_TESTBD_BADBLOCK_NOREAD',
-]
 define.FILES = 10
 code = '''
-    lfs_format(&lfs, &cfg) => 0;
-    lfs_mount(&lfs, &cfg) => 0;
-    lfs_mkdir(&lfs, "roadrunner") => 0;
-    lfs_unmount(&lfs) => 0;
-
    uint32_t run_cycles[2];
    const uint32_t run_block_count[2] = {LFS_BLOCK_COUNT/2, LFS_BLOCK_COUNT};

@@ -182,6 +184,11 @@ code = '''
                    (b < run_block_count[run]) ? 0 : LFS_ERASE_CYCLES) => 0;
        }

+        lfs_format(&lfs, &cfg) => 0;
+        lfs_mount(&lfs, &cfg) => 0;
+        lfs_mkdir(&lfs, "roadrunner") => 0;
+        lfs_unmount(&lfs) => 0;
+
        uint32_t cycle = 0;
        while (true) {
            lfs_mount(&lfs, &cfg) => 0;
@@ -199,6 +206,9 @@ code = '''
                    lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                    assert(res == 1 || res == LFS_ERR_NOSPC);
                    if (res == LFS_ERR_NOSPC) {
+                        err = lfs_file_close(&lfs, &file);
+                        assert(err == 0 || err == LFS_ERR_NOSPC);
+                        lfs_unmount(&lfs) => 0;
                        goto exhausted;
                    }
                }
@@ -206,9 +216,10 @@ code = '''
                err = lfs_file_close(&lfs, &file);
                assert(err == 0 || err == LFS_ERR_NOSPC);
                if (err == LFS_ERR_NOSPC) {
+                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
-            }    
+            }

            for (uint32_t i = 0; i < FILES; i++) {
                // check for errors
@@ -225,7 +236,7 @@ code = '''
                }

                lfs_file_close(&lfs, &file) => 0;
-            }    
+            }
            lfs_unmount(&lfs) => 0;

            cycle += 1;
@@ -238,7 +249,7 @@ exhausted:
            // check for errors
            sprintf(path, "roadrunner/test%d", i);
            lfs_stat(&lfs, path, &info) => 0;
-        }    
+        }
        lfs_unmount(&lfs) => 0;

        run_cycles[run] = cycle;
@@ -247,22 +258,15 @@ exhausted:
    }

    // check we increased the lifetime by 2x with ~10% error
-    LFS_ASSERT(run_cycles[1] > 2*run_cycles[0]-run_cycles[0]/10);
+    LFS_ASSERT(run_cycles[1]*110/100 > 2*run_cycles[0]);
 '''

 [[case]] # wear-level test + expanding superblock
-define.LFS_ERASE_CYCLES = 10
-define.LFS_BLOCK_COUNT = 256 # small bd so it runs faster
+define.LFS_ERASE_CYCLES = 20
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
 define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
-define.LFS_BADBLOCK_BEHAVIOR = [
-    'LFS_TESTBD_BADBLOCK_NOPROG',
-    'LFS_TESTBD_BADBLOCK_NOERASE',
-    'LFS_TESTBD_BADBLOCK_NOREAD',
-]
 define.FILES = 10
 code = '''
-    lfs_format(&lfs, &cfg) => 0;
-
    uint32_t run_cycles[2];
    const uint32_t run_block_count[2] = {LFS_BLOCK_COUNT/2, LFS_BLOCK_COUNT};

@@ -272,6 +276,8 @@ code = '''
                    (b < run_block_count[run]) ? 0 : LFS_ERASE_CYCLES) => 0;
        }

+        lfs_format(&lfs, &cfg) => 0;
+
        uint32_t cycle = 0;
        while (true) {
            lfs_mount(&lfs, &cfg) => 0;
@@ -289,6 +295,9 @@ code = '''
                    lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
                    assert(res == 1 || res == LFS_ERR_NOSPC);
                    if (res == LFS_ERR_NOSPC) {
+                        err = lfs_file_close(&lfs, &file);
+                        assert(err == 0 || err == LFS_ERR_NOSPC);
+                        lfs_unmount(&lfs) => 0;
                        goto exhausted;
                    }
                }
@@ -296,9 +305,10 @@ code = '''
                err = lfs_file_close(&lfs, &file);
                assert(err == 0 || err == LFS_ERR_NOSPC);
                if (err == LFS_ERR_NOSPC) {
+                    lfs_unmount(&lfs) => 0;
                    goto exhausted;
                }
-            }    
+            }

            for (uint32_t i = 0; i < FILES; i++) {
                // check for errors
@@ -315,7 +325,7 @@ code = '''
                }

                lfs_file_close(&lfs, &file) => 0;
-            }    
+            }
            lfs_unmount(&lfs) => 0;

            cycle += 1;
@@ -328,7 +338,7 @@ exhausted:
            // check for errors
            sprintf(path, "test%d", i);
            lfs_stat(&lfs, path, &info) => 0;
-        }    
+        }
        lfs_unmount(&lfs) => 0;

        run_cycles[run] = cycle;
@@ -337,5 +347,119 @@ exhausted:
    }

    // check we increased the lifetime by 2x with ~10% error
-    LFS_ASSERT(run_cycles[1] > 2*run_cycles[0]-run_cycles[0]/10);
+    LFS_ASSERT(run_cycles[1]*110/100 > 2*run_cycles[0]);
 '''
+
+[[case]] # test that we wear blocks roughly evenly
+define.LFS_ERASE_CYCLES = 0xffffffff
+define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
+define.LFS_BLOCK_CYCLES = [5, 4, 3, 2, 1]
+define.CYCLES = 100
+define.FILES = 10
+if = 'LFS_BLOCK_CYCLES < CYCLES/10'
+code = '''
+    lfs_format(&lfs, &cfg) => 0;
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "roadrunner") => 0;
+    lfs_unmount(&lfs) => 0;
+
+    uint32_t cycle = 0;
+    while (cycle < CYCLES) {
+        lfs_mount(&lfs, &cfg) => 0;
+        for (uint32_t i = 0; i < FILES; i++) {
+            // chose name, roughly random seed, and random 2^n size
+            sprintf(path, "roadrunner/test%d", i);
+            srand(cycle * i);
+            size = 1 << 4; //((rand() % 10)+2);
+
+            lfs_file_open(&lfs, &file, path,
+                    LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;
+
+            for (lfs_size_t j = 0; j < size; j++) {
+                char c = 'a' + (rand() % 26);
+                lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
+                assert(res == 1 || res == LFS_ERR_NOSPC);
+                if (res == LFS_ERR_NOSPC) {
+                    err = lfs_file_close(&lfs, &file);
+                    assert(err == 0 || err == LFS_ERR_NOSPC);
+                    lfs_unmount(&lfs) => 0;
+                    goto exhausted;
+                }
+            }
+
+            err = lfs_file_close(&lfs, &file);
+            assert(err == 0 || err == LFS_ERR_NOSPC);
+            if (err == LFS_ERR_NOSPC) {
+                lfs_unmount(&lfs) => 0;
+                goto exhausted;
+            }
+        }
+
+        for (uint32_t i = 0; i < FILES; i++) {
+            // check for errors
+            sprintf(path, "roadrunner/test%d", i);
+            srand(cycle * i);
+            size = 1 << 4; //((rand() % 10)+2);
+
+            lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
+            for (lfs_size_t j = 0; j < size; j++) {
+                char c = 'a' + (rand() % 26);
+                char r;
+                lfs_file_read(&lfs, &file, &r, 1) => 1;
+                assert(r == c);
+            }
+
+            lfs_file_close(&lfs, &file) => 0;
+        }
+        lfs_unmount(&lfs) => 0;
+
+        cycle += 1;
+    }
+
+exhausted:
+    // should still be readable
+    lfs_mount(&lfs, &cfg) => 0;
+    for (uint32_t i = 0; i < FILES; i++) {
+        // check for errors
+        sprintf(path, "roadrunner/test%d", i);
+        lfs_stat(&lfs, path, &info) => 0;
+    }
+    lfs_unmount(&lfs) => 0;
+
+    LFS_WARN("completed %d cycles", cycle);
+
+    // check the wear on our block device
+    lfs_testbd_wear_t minwear = -1;
+    lfs_testbd_wear_t totalwear = 0;
+    lfs_testbd_wear_t maxwear = 0;
+    // skip 0 and 1 as superblock movement is intentionally avoided
+    for (lfs_block_t b = 2; b < LFS_BLOCK_COUNT; b++) {
+        lfs_testbd_wear_t wear = lfs_testbd_getwear(&cfg, b);
+        printf("%08x: wear %d\n", b, wear);
+        assert(wear >= 0);
+        if (wear < minwear) {
+            minwear = wear;
+        }
+        if (wear > maxwear) {
+            maxwear = wear;
+        }
+        totalwear += wear;
+    }
+    lfs_testbd_wear_t avgwear = totalwear / LFS_BLOCK_COUNT;
+    LFS_WARN("max wear: %d cycles", maxwear);
+    LFS_WARN("avg wear: %d cycles", totalwear / LFS_BLOCK_COUNT);
+    LFS_WARN("min wear: %d cycles", minwear);
+
+    // find standard deviation^2
+    lfs_testbd_wear_t dev2 = 0;
+    for (lfs_block_t b = 2; b < LFS_BLOCK_COUNT; b++) {
+        lfs_testbd_wear_t wear = lfs_testbd_getwear(&cfg, b);
+        assert(wear >= 0);
+        lfs_testbd_swear_t diff = wear - avgwear;
+        dev2 += diff*diff;
+    }
+    dev2 /= totalwear;
+    LFS_WARN("std dev^2: %d", dev2);
+    assert(dev2 < 8);
+'''
+
--- a/tests/test_move.toml
+++ b/tests/test_move.toml
@@ -148,6 +148,7 @@ code = '''

 [[case]] # move file corrupt source and dest
 in = "lfs.c"
+if = 'LFS_PROG_SIZE <= 0x3fe' # only works with one crc per commit
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
@@ -239,6 +240,7 @@ code = '''

 [[case]] # move file after corrupt
 in = "lfs.c"
+if = 'LFS_PROG_SIZE <= 0x3fe' # only works with one crc per commit
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
@@ -593,6 +595,7 @@ code = '''

 [[case]] # move dir corrupt source and dest
 in = "lfs.c"
+if = 'LFS_PROG_SIZE <= 0x3fe' # only works with one crc per commit
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
@@ -692,6 +695,7 @@ code = '''

 [[case]] # move dir after corrupt
 in = "lfs.c"
+if = 'LFS_PROG_SIZE <= 0x3fe' # only works with one crc per commit
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
--- a/tests/test_orphans.toml
+++ b/tests/test_orphans.toml
@@ -1,5 +1,6 @@
 [[case]] # orphan test
 in = "lfs.c"
+if = 'LFS_PROG_SIZE <= 0x3fe' # only works with one crc per commit
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
@@ -57,10 +58,12 @@ code = '''

 [[case]] # reentrant testing for orphans, basically just spam mkdir/remove
 reentrant = true
+# TODO fix this case, caused by non-DAG trees
+if = '!(DEPTH == 3 && LFS_CACHE_SIZE != 64)'
 define = [
-    {FILES=6,  DEPTH=1, CYCLES=50},
-    {FILES=26, DEPTH=1, CYCLES=50},
-    {FILES=3,  DEPTH=3, CYCLES=50},
+    {FILES=6,  DEPTH=1, CYCLES=20},
+    {FILES=26, DEPTH=1, CYCLES=20},
+    {FILES=3,  DEPTH=3, CYCLES=20},
 ]
 code = '''
    err = lfs_mount(&lfs, &cfg);
--- a/tests/test_paths.toml
+++ b/tests/test_paths.toml
@@ -247,14 +247,14 @@ code = '''
    lfs_mkdir(&lfs, "coffee/coldcoffee") => 0;

    memset(path, 'w', LFS_NAME_MAX+1);
-    path[LFS_NAME_MAX+2] = '\0';
+    path[LFS_NAME_MAX+1] = '\0';
    lfs_mkdir(&lfs, path) => LFS_ERR_NAMETOOLONG;
    lfs_file_open(&lfs, &file, path, LFS_O_WRONLY | LFS_O_CREAT)
            => LFS_ERR_NAMETOOLONG;

    memcpy(path, "coffee/", strlen("coffee/"));
    memset(path+strlen("coffee/"), 'w', LFS_NAME_MAX+1);
-    path[strlen("coffee/")+LFS_NAME_MAX+2] = '\0';
+    path[strlen("coffee/")+LFS_NAME_MAX+1] = '\0';
    lfs_mkdir(&lfs, path) => LFS_ERR_NAMETOOLONG;
    lfs_file_open(&lfs, &file, path, LFS_O_WRONLY | LFS_O_CREAT)
            => LFS_ERR_NAMETOOLONG;
@@ -270,7 +270,6 @@ code = '''
    lfs_mkdir(&lfs, "coffee/warmcoffee") => 0;
    lfs_mkdir(&lfs, "coffee/coldcoffee") => 0;

-    lfs_mount(&lfs, &cfg) => 0;
    memset(path, 'w', LFS_NAME_MAX);
    path[LFS_NAME_MAX] = '\0';
    lfs_mkdir(&lfs, path) => 0;
--- a/tests/test_relocations.toml
+++ b/tests/test_relocations.toml
@@ -147,10 +147,12 @@ code = '''
         # orphan testing, except here we also set block_cycles so that
         # 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)'
 define = [
-    {FILES=6,  DEPTH=1, CYCLES=50, LFS_BLOCK_CYCLES=1},
-    {FILES=26, DEPTH=1, CYCLES=50, LFS_BLOCK_CYCLES=1},
-    {FILES=3,  DEPTH=3, CYCLES=50, LFS_BLOCK_CYCLES=1},
+    {FILES=6,  DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
+    {FILES=26, DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
+    {FILES=3,  DEPTH=3, CYCLES=20, LFS_BLOCK_CYCLES=1},
 ]
 code = '''
    err = lfs_mount(&lfs, &cfg);
@@ -207,10 +209,12 @@ 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)'
 define = [
-    {FILES=6,  DEPTH=1, CYCLES=50, LFS_BLOCK_CYCLES=1},
-    {FILES=26, DEPTH=1, CYCLES=50, LFS_BLOCK_CYCLES=1},
-    {FILES=3,  DEPTH=3, CYCLES=50, LFS_BLOCK_CYCLES=1},
+    {FILES=6,  DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
+    {FILES=26, DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
+    {FILES=3,  DEPTH=3, CYCLES=20, LFS_BLOCK_CYCLES=1},
 ]
 code = '''
    err = lfs_mount(&lfs, &cfg);
--- a/tests/test_superblocks.toml
+++ b/tests/test_superblocks.toml
@@ -27,41 +27,55 @@ code = '''
 '''

 [[case]] # expanding superblock
-define.BLOCK_CYCLES = [32, 33, 1]
+define.LFS_BLOCK_CYCLES = [32, 33, 1]
 define.N = [10, 100, 1000]
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    lfs_mount(&lfs, &cfg) => 0;
    for (int i = 0; i < N; i++) {
-        lfs_mkdir(&lfs, "dummy") => 0;
+        lfs_file_open(&lfs, &file, "dummy",
+                LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
+        lfs_file_close(&lfs, &file) => 0;
        lfs_stat(&lfs, "dummy", &info) => 0;
        assert(strcmp(info.name, "dummy") == 0);
+        assert(info.type == LFS_TYPE_REG);
        lfs_remove(&lfs, "dummy") => 0;
    }
    lfs_unmount(&lfs) => 0;

    // one last check after power-cycle
    lfs_mount(&lfs, &cfg) => 0;
-    lfs_mkdir(&lfs, "dummy") => 0;
+    lfs_file_open(&lfs, &file, "dummy",
+            LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
+    lfs_file_close(&lfs, &file) => 0;
    lfs_stat(&lfs, "dummy", &info) => 0;
    assert(strcmp(info.name, "dummy") == 0);
+    assert(info.type == LFS_TYPE_REG);
    lfs_unmount(&lfs) => 0;
 '''

 [[case]] # expanding superblock with power cycle
-define.BLOCK_CYCLES = [32, 33, 1]
+define.LFS_BLOCK_CYCLES = [32, 33, 1]
 define.N = [10, 100, 1000]
 code = '''
    lfs_format(&lfs, &cfg) => 0;
    for (int i = 0; i < N; i++) {
        lfs_mount(&lfs, &cfg) => 0;
        // remove lingering dummy?
-        err = lfs_remove(&lfs, "dummy");
+        err = lfs_stat(&lfs, "dummy", &info);
        assert(err == 0 || (err == LFS_ERR_NOENT && i == 0));
-        
-        lfs_mkdir(&lfs, "dummy") => 0;
+        if (!err) {
+            assert(strcmp(info.name, "dummy") == 0);
+            assert(info.type == LFS_TYPE_REG);
+            lfs_remove(&lfs, "dummy") => 0;
+        }
+
+        lfs_file_open(&lfs, &file, "dummy",
+                LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
+        lfs_file_close(&lfs, &file) => 0;
        lfs_stat(&lfs, "dummy", &info) => 0;
        assert(strcmp(info.name, "dummy") == 0);
+        assert(info.type == LFS_TYPE_REG);
        lfs_unmount(&lfs) => 0;
    }

@@ -69,11 +83,12 @@ code = '''
    lfs_mount(&lfs, &cfg) => 0;
    lfs_stat(&lfs, "dummy", &info) => 0;
    assert(strcmp(info.name, "dummy") == 0);
+    assert(info.type == LFS_TYPE_REG);
    lfs_unmount(&lfs) => 0;
 '''

 [[case]] # reentrant expanding superblock
-define.BLOCK_CYCLES = [2, 1]
+define.LFS_BLOCK_CYCLES = [2, 1]
 define.N = 24
 reentrant = true
 code = '''
@@ -85,12 +100,20 @@ code = '''

    for (int i = 0; i < N; i++) {
        // remove lingering dummy?
-        err = lfs_remove(&lfs, "dummy");
+        err = lfs_stat(&lfs, "dummy", &info);
        assert(err == 0 || (err == LFS_ERR_NOENT && i == 0));
-        
-        lfs_mkdir(&lfs, "dummy") => 0;
+        if (!err) {
+            assert(strcmp(info.name, "dummy") == 0);
+            assert(info.type == LFS_TYPE_REG);
+            lfs_remove(&lfs, "dummy") => 0;
+        }
+
+        lfs_file_open(&lfs, &file, "dummy",
+                LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
+        lfs_file_close(&lfs, &file) => 0;
        lfs_stat(&lfs, "dummy", &info) => 0;
        assert(strcmp(info.name, "dummy") == 0);
+        assert(info.type == LFS_TYPE_REG);
    }

    lfs_unmount(&lfs) => 0;
@@ -99,5 +122,6 @@ code = '''
    lfs_mount(&lfs, &cfg) => 0;
    lfs_stat(&lfs, "dummy", &info) => 0;
    assert(strcmp(info.name, "dummy") == 0);
+    assert(info.type == LFS_TYPE_REG);
    lfs_unmount(&lfs) => 0;
 '''
--- a/tests/test_truncate.toml
+++ b/tests/test_truncate.toml
@@ -100,7 +100,7 @@ code = '''
    lfs_file_open(&lfs, &file, "sequence",
            LFS_O_RDWR | LFS_O_CREAT | LFS_O_TRUNC) => 0;

-    size = lfs.cfg->cache_size;
+    size = lfs_min(lfs.cfg->cache_size, sizeof(buffer)/2);
    lfs_size_t qsize = size / 4;
    uint8_t *wb = buffer;
    uint8_t *rb = buffer + size;