From 85abdf1c9a64600794b63bd8d95f524d69d6c38b Mon Sep 17 00:00:00 2001
From: geky-bot <bot@geky.net>
Date: Fri, 30 Jun 2023 18:37:28 +0000
Subject: [PATCH 01/12] Squashed 'littlefs/' changes from 66f0756..611c9b2

611c9b2 Merge pull request #848 from littlefs-project/devel
a942cdb Bumped minor version to v2.7
225fc31 Merge pull request #846 from littlefs-project/link-chan-fatfs
5db368c Merge pull request #839 from littlefs-project/configurable-disk-version
f09c6a4 Merge pull request #838 from littlefs-project/fs-stat
79cc75d Added LFS_MULTIVERSION and testing of lfs2.0 to CI
eb9af7a Added LFS_MULTIVERSION, made lfs2.0 support a compile-time option
b72c96d Added support for writing on-disk version lfs2.0
265692e Removed fsinfo.block_usage for now
08a132e Added a link to ChaN's FatFS implementation
c5fb3f1 Changed fsinfo.minor_version -> fsinfo.disk_version
8610f7c Increased context on failures for Valgrind in CI
a51be18 Removed previous-version lfsp_fs_stat checks in test_compat
a7ccc1d Promoted lfs_gstate_needssuperblock to be available in readonly builds
fdee127 Removed use of LFS_VERSION in test_compat
87bbf1d Added lfs_fs_stat for access to filesystem status/configuration

git-subtree-dir: littlefs
git-subtree-split: 611c9b20db2b99faee261daa7cc9bbe175d3eaca
---
 .github/workflows/release.yml |   2 +-
 .github/workflows/test.yml    |  62 ++++++++++-
 README.md                     |   5 +
 lfs.c                         | 202 ++++++++++++++++++++++++++--------
 lfs.h                         |  31 +++++-
 runners/test_runner.c         |  15 +++
 runners/test_runner.h         |   7 +-
 tests/test_compat.toml        | 165 +++++++++++++++++++++------
 tests/test_powerloss.toml     |   5 +-
 tests/test_superblocks.toml   |  48 ++++++++
 10 files changed, 451 insertions(+), 91 deletions(-)

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b2ead2e..c0d446d 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -102,7 +102,7 @@ jobs:
           # sizes table
           i=0
           j=0
-          for c in "" readonly threadsafe migrate error-asserts
+          for c in "" readonly threadsafe multiversion migrate error-asserts
           do
             # per-config results
             c_or_default=${c:-default}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 2cee352..ccb08fe 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -170,6 +170,27 @@ jobs:
           cp lfs.data.csv sizes/${{matrix.arch}}-threadsafe.data.csv
           cp lfs.stack.csv sizes/${{matrix.arch}}-threadsafe.stack.csv
           cp lfs.structs.csv sizes/${{matrix.arch}}-threadsafe.structs.csv
+      - name: sizes-multiversion
+        run: |
+          make clean
+          CFLAGS="$CFLAGS \
+            -DLFS_NO_ASSERT \
+            -DLFS_NO_DEBUG \
+            -DLFS_NO_WARN \
+            -DLFS_NO_ERROR \
+            -DLFS_MULTIVERSION" \
+            make lfs.code.csv lfs.data.csv lfs.stack.csv lfs.structs.csv
+          ./scripts/structs.py -u lfs.structs.csv
+          ./scripts/summary.py lfs.code.csv lfs.data.csv lfs.stack.csv \
+            -bfunction \
+            -fcode=code_size \
+            -fdata=data_size \
+            -fstack=stack_limit --max=stack_limit
+          mkdir -p sizes
+          cp lfs.code.csv sizes/${{matrix.arch}}-multiversion.code.csv
+          cp lfs.data.csv sizes/${{matrix.arch}}-multiversion.data.csv
+          cp lfs.stack.csv sizes/${{matrix.arch}}-multiversion.stack.csv
+          cp lfs.structs.csv sizes/${{matrix.arch}}-multiversion.structs.csv
       - name: sizes-migrate
         run: |
           make clean
@@ -353,6 +374,42 @@ jobs:
         run: |
           CFLAGS="$CFLAGS -DLFS_NO_INTRINSICS" make test
 
+  # run LFS_MULTIVERSION tests
+  test-multiversion:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v2
+      - name: install
+        run: |
+          # need a few things
+          sudo apt-get update -qq
+          sudo apt-get install -qq gcc python3 python3-pip
+          pip3 install toml
+          gcc --version
+          python3 --version
+      - name: test-multiversion
+        run: |
+          CFLAGS="$CFLAGS -DLFS_MULTIVERSION" make test
+
+  # run tests on the older version lfs2.0
+  test-lfs2_0:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v2
+      - name: install
+        run: |
+          # need a few things
+          sudo apt-get update -qq
+          sudo apt-get install -qq gcc python3 python3-pip
+          pip3 install toml
+          gcc --version
+          python3 --version
+      - name: test-lfs2_0
+        run: |
+          CFLAGS="$CFLAGS -DLFS_MULTIVERSION" \
+          TESTFLAGS="$TESTFLAGS -DDISK_VERSION=0x00020000" \
+            make test
+
   # run under Valgrind to check for memory errors
   test-valgrind:
     runs-on: ubuntu-22.04
@@ -371,7 +428,8 @@ jobs:
       # on one geometry
       - name: test-valgrind
         run: |
-          TESTFLAGS="$TESTFLAGS --valgrind -Gdefault -Pnone" make test
+          TESTFLAGS="$TESTFLAGS --valgrind --context=1024 -Gdefault -Pnone" \
+            make test
 
   # test that compilation is warning free under clang
   # run with Clang, mostly to check for Clang-specific warnings
@@ -684,7 +742,7 @@ jobs:
           # sizes table
           i=0
           j=0
-          for c in "" readonly threadsafe migrate error-asserts
+          for c in "" readonly threadsafe multiversion migrate error-asserts
           do
             # per-config results
             c_or_default=${c:-default}
diff --git a/README.md b/README.md
index 3afddfd..df7ee00 100644
--- a/README.md
+++ b/README.md
@@ -250,6 +250,10 @@ License Identifiers that are here available: http://spdx.org/licenses/
   MCUs. It offers static wear-leveling and power-resilience with only a fixed
   _O(|address|)_ pointer structure stored on each block and in RAM.
 
+- [ChaN's FatFs] - A lightweight reimplementation of the infamous FAT filesystem
+  for microcontroller-scale devices. Due to limitations of FAT it can't provide
+  power-loss resilience, but it does allow easy interop with PCs.
+
 - [chamelon] - A pure-OCaml implementation of (most of) littlefs, designed for
   use with the MirageOS library operating system project. It is interoperable
   with the reference implementation, with some caveats.
@@ -266,6 +270,7 @@ License Identifiers that are here available: http://spdx.org/licenses/
 [LittleFileSystem]: https://os.mbed.com/docs/mbed-os/latest/apis/littlefilesystem.html
 [SPIFFS]: https://github.com/pellepl/spiffs
 [Dhara]: https://github.com/dlbeer/dhara
+[ChaN's FatFs]: http://elm-chan.org/fsw/ff/00index_e.html
 [littlefs-python]: https://pypi.org/project/littlefs-python/
 [littlefs2-rust]: https://crates.io/crates/littlefs2
 [chamelon]: https://github.com/yomimono/chamelon
diff --git a/lfs.c b/lfs.c
index f0daf54..38b825d 100644
--- a/lfs.c
+++ b/lfs.c
@@ -415,11 +415,11 @@ static inline uint8_t lfs_gstate_getorphans(const lfs_gstate_t *a) {
 static inline bool lfs_gstate_hasmove(const lfs_gstate_t *a) {
     return lfs_tag_type1(a->tag);
 }
+#endif
 
 static inline bool lfs_gstate_needssuperblock(const lfs_gstate_t *a) {
     return lfs_tag_size(a->tag) >> 9;
 }
-#endif
 
 static inline bool lfs_gstate_hasmovehere(const lfs_gstate_t *a,
         const lfs_block_t *pair) {
@@ -518,6 +518,28 @@ static void lfs_mlist_append(lfs_t *lfs, struct lfs_mlist *mlist) {
     lfs->mlist = mlist;
 }
 
+// some other filesystem operations
+static uint32_t lfs_fs_disk_version(lfs_t *lfs) {
+    (void)lfs;
+#ifdef LFS_MULTIVERSION
+    if (lfs->cfg->disk_version) {
+        return lfs->cfg->disk_version;
+    } else
+#endif
+    {
+        return LFS_DISK_VERSION;
+    }
+}
+
+static uint16_t lfs_fs_disk_version_major(lfs_t *lfs) {
+    return 0xffff & (lfs_fs_disk_version(lfs) >> 16);
+
+}
+
+static uint16_t lfs_fs_disk_version_minor(lfs_t *lfs) {
+    return 0xffff & (lfs_fs_disk_version(lfs) >> 0);
+}
+
 
 /// Internal operations predeclared here ///
 #ifndef LFS_READONLY
@@ -535,7 +557,6 @@ static int lfs_file_outline(lfs_t *lfs, lfs_file_t *file);
 static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file);
 
 static int lfs_fs_deorphan(lfs_t *lfs, bool powerloss);
-static void lfs_fs_prepsuperblock(lfs_t *lfs, bool needssuperblock);
 static int lfs_fs_preporphans(lfs_t *lfs, int8_t orphans);
 static void lfs_fs_prepmove(lfs_t *lfs,
         uint16_t id, const lfs_block_t pair[2]);
@@ -546,6 +567,8 @@ static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t dir[2],
 static int lfs_fs_forceconsistency(lfs_t *lfs);
 #endif
 
+static void lfs_fs_prepsuperblock(lfs_t *lfs, bool needssuperblock);
+
 #ifdef LFS_MIGRATE
 static int lfs1_traverse(lfs_t *lfs,
         int (*cb)(void*, lfs_block_t), void *data);
@@ -1110,7 +1133,8 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
 
             // next commit not yet programmed?
             if (!lfs_tag_isvalid(tag)) {
-                maybeerased = true;
+                // we only might be erased if the last tag was a crc
+                maybeerased = (lfs_tag_type2(ptag) == LFS_TYPE_CCRC);
                 break;
             // out of range?
             } else if (off + lfs_tag_dsize(tag) > lfs->cfg->block_size) {
@@ -1155,14 +1179,11 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
                 dir->tail[1] = temptail[1];
                 dir->split = tempsplit;
 
-                // reset crc
+                // reset crc, hasfcrc
                 crc = 0xffffffff;
                 continue;
             }
 
-            // fcrc is only valid when last tag was a crc
-            hasfcrc = false;
-
             // crc the entry first, hopefully leaving it in the cache
             err = lfs_bd_crc(lfs,
                     NULL, &lfs->rcache, lfs->cfg->block_size,
@@ -1256,20 +1277,33 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
 
         // did we end on a valid commit? we may have an erased block
         dir->erased = false;
-        if (maybeerased && hasfcrc && dir->off % lfs->cfg->prog_size == 0) {
-            // check for an fcrc matching the next prog's erased state, if
-            // this failed most likely a previous prog was interrupted, we
-            // need a new erase
-            uint32_t fcrc_ = 0xffffffff;
-            int err = lfs_bd_crc(lfs,
-                    NULL, &lfs->rcache, lfs->cfg->block_size,
-                    dir->pair[0], dir->off, fcrc.size, &fcrc_);
-            if (err && err != LFS_ERR_CORRUPT) {
-                return err;
-            }
+        if (maybeerased && dir->off % lfs->cfg->prog_size == 0) {
+        #ifdef LFS_MULTIVERSION
+            // note versions < lfs2.1 did not have fcrc tags, if
+            // we're < lfs2.1 treat missing fcrc as erased data
+            //
+            // we don't strictly need to do this, but otherwise writing
+            // to lfs2.0 disks becomes very inefficient
+            if (lfs_fs_disk_version(lfs) < 0x00020001) {
+                dir->erased = true;
+
+            } else
+        #endif
+            if (hasfcrc) {
+                // check for an fcrc matching the next prog's erased state, if
+                // this failed most likely a previous prog was interrupted, we
+                // need a new erase
+                uint32_t fcrc_ = 0xffffffff;
+                int err = lfs_bd_crc(lfs,
+                        NULL, &lfs->rcache, lfs->cfg->block_size,
+                        dir->pair[0], dir->off, fcrc.size, &fcrc_);
+                if (err && err != LFS_ERR_CORRUPT) {
+                    return err;
+                }
 
-            // found beginning of erased part?
-            dir->erased = (fcrc_ == fcrc.crc);
+                // found beginning of erased part?
+                dir->erased = (fcrc_ == fcrc.crc);
+            }
         }
 
         // synthetic move
@@ -1605,22 +1639,34 @@ static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {
                 return err;
             }
 
-            // find the expected fcrc, don't bother avoiding a reread
-            // of the eperturb, it should still be in our cache
-            struct lfs_fcrc fcrc = {.size=lfs->cfg->prog_size, .crc=0xffffffff};
-            err = lfs_bd_crc(lfs,
-                    NULL, &lfs->rcache, lfs->cfg->prog_size,
-                    commit->block, noff, fcrc.size, &fcrc.crc);
-            if (err && err != LFS_ERR_CORRUPT) {
-                return err;
-            }
+        #ifdef LFS_MULTIVERSION
+            // unfortunately fcrcs break mdir fetching < lfs2.1, so only write
+            // these if we're a >= lfs2.1 filesystem
+            if (lfs_fs_disk_version(lfs) <= 0x00020000) {
+                // don't write fcrc
+            } else
+        #endif
+            {
+                // find the expected fcrc, don't bother avoiding a reread
+                // of the eperturb, it should still be in our cache
+                struct lfs_fcrc fcrc = {
+                    .size = lfs->cfg->prog_size,
+                    .crc = 0xffffffff
+                };
+                err = lfs_bd_crc(lfs,
+                        NULL, &lfs->rcache, lfs->cfg->prog_size,
+                        commit->block, noff, fcrc.size, &fcrc.crc);
+                if (err && err != LFS_ERR_CORRUPT) {
+                    return err;
+                }
 
-            lfs_fcrc_tole32(&fcrc);
-            err = lfs_dir_commitattr(lfs, commit,
-                    LFS_MKTAG(LFS_TYPE_FCRC, 0x3ff, sizeof(struct lfs_fcrc)),
-                    &fcrc);
-            if (err) {
-                return err;
+                lfs_fcrc_tole32(&fcrc);
+                err = lfs_dir_commitattr(lfs, commit,
+                        LFS_MKTAG(LFS_TYPE_FCRC, 0x3ff, sizeof(struct lfs_fcrc)),
+                        &fcrc);
+                if (err) {
+                    return err;
+                }
             }
         }
 
@@ -4051,6 +4097,15 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     lfs->cfg = cfg;
     int err = 0;
 
+#ifdef LFS_MULTIVERSION
+    // this driver only supports minor version < current minor version
+    LFS_ASSERT(!lfs->cfg->disk_version || (
+            (0xffff & (lfs->cfg->disk_version >> 16))
+                    == LFS_DISK_VERSION_MAJOR
+                && (0xffff & (lfs->cfg->disk_version >> 0))
+                    <= LFS_DISK_VERSION_MINOR));
+#endif
+
     // check that bool is a truthy-preserving type
     //
     // note the most common reason for this failure is a before-c99 compiler,
@@ -4208,7 +4263,7 @@ static int lfs_rawformat(lfs_t *lfs, const struct lfs_config *cfg) {
 
         // write one superblock
         lfs_superblock_t superblock = {
-            .version     = LFS_DISK_VERSION,
+            .version     = lfs_fs_disk_version(lfs),
             .block_size  = lfs->cfg->block_size,
             .block_count = lfs->cfg->block_count,
             .name_max    = lfs->name_max,
@@ -4306,12 +4361,14 @@ static int lfs_rawmount(lfs_t *lfs, const struct lfs_config *cfg) {
             // check version
             uint16_t major_version = (0xffff & (superblock.version >> 16));
             uint16_t minor_version = (0xffff & (superblock.version >>  0));
-            if ((major_version != LFS_DISK_VERSION_MAJOR ||
-                 minor_version > LFS_DISK_VERSION_MINOR)) {
+            if (major_version != lfs_fs_disk_version_major(lfs)
+                    || minor_version > lfs_fs_disk_version_minor(lfs)) {
                 LFS_ERROR("Invalid version "
                         "v%"PRIu16".%"PRIu16" != v%"PRIu16".%"PRIu16,
-                        major_version, minor_version,
-                        LFS_DISK_VERSION_MAJOR, LFS_DISK_VERSION_MINOR);
+                        major_version,
+                        minor_version,
+                        lfs_fs_disk_version_major(lfs),
+                        lfs_fs_disk_version_minor(lfs));
                 err = LFS_ERR_INVAL;
                 goto cleanup;
             }
@@ -4319,16 +4376,16 @@ static int lfs_rawmount(lfs_t *lfs, const struct lfs_config *cfg) {
             // found older minor version? set an in-device only bit in the
             // gstate so we know we need to rewrite the superblock before
             // the first write
-            if (minor_version < LFS_DISK_VERSION_MINOR) {
+            if (minor_version < lfs_fs_disk_version_minor(lfs)) {
                 LFS_DEBUG("Found older minor version "
                         "v%"PRIu16".%"PRIu16" < v%"PRIu16".%"PRIu16,
-                        major_version, minor_version,
-                        LFS_DISK_VERSION_MAJOR, LFS_DISK_VERSION_MINOR);
-            #ifndef LFS_READONLY
+                        major_version,
+                        minor_version,
+                        lfs_fs_disk_version_major(lfs),
+                        lfs_fs_disk_version_minor(lfs));
                 // note this bit is reserved on disk, so fetching more gstate
                 // will not interfere here
                 lfs_fs_prepsuperblock(lfs, true);
-            #endif
             }
 
             // check superblock configuration
@@ -4421,6 +4478,42 @@ static int lfs_rawunmount(lfs_t *lfs) {
 
 
 /// Filesystem filesystem operations ///
+static int lfs_fs_rawstat(lfs_t *lfs, struct lfs_fsinfo *fsinfo) {
+    // if the superblock is up-to-date, we must be on the most recent
+    // minor version of littlefs
+    if (!lfs_gstate_needssuperblock(&lfs->gstate)) {
+        fsinfo->disk_version = lfs_fs_disk_version(lfs);
+
+    // otherwise we need to read the minor version on disk
+    } else {
+        // fetch the superblock
+        lfs_mdir_t dir;
+        int err = lfs_dir_fetch(lfs, &dir, lfs->root);
+        if (err) {
+            return err;
+        }
+
+        lfs_superblock_t superblock;
+        lfs_stag_t tag = lfs_dir_get(lfs, &dir, LFS_MKTAG(0x7ff, 0x3ff, 0),
+                LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
+                &superblock);
+        if (tag < 0) {
+            return tag;
+        }
+        lfs_superblock_fromle32(&superblock);
+
+        // read the on-disk version
+        fsinfo->disk_version = superblock.version;
+    }
+
+    // other on-disk configuration, we cache all of these for internal use
+    fsinfo->name_max = lfs->name_max;
+    fsinfo->file_max = lfs->file_max;
+    fsinfo->attr_max = lfs->attr_max;
+
+    return 0;
+}
+
 int lfs_fs_rawtraverse(lfs_t *lfs,
         int (*cb)(void *data, lfs_block_t block), void *data,
         bool includeorphans) {
@@ -4631,12 +4724,10 @@ static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t pair[2],
 }
 #endif
 
-#ifndef LFS_READONLY
 static void lfs_fs_prepsuperblock(lfs_t *lfs, bool needssuperblock) {
     lfs->gstate.tag = (lfs->gstate.tag & ~LFS_MKTAG(0, 0, 0x200))
             | (uint32_t)needssuperblock << 9;
 }
-#endif
 
 #ifndef LFS_READONLY
 static int lfs_fs_preporphans(lfs_t *lfs, int8_t orphans) {
@@ -4678,7 +4769,7 @@ static int lfs_fs_desuperblock(lfs_t *lfs) {
 
     // write a new superblock
     lfs_superblock_t superblock = {
-        .version     = LFS_DISK_VERSION,
+        .version     = lfs_fs_disk_version(lfs),
         .block_size  = lfs->cfg->block_size,
         .block_count = lfs->cfg->block_count,
         .name_max    = lfs->name_max,
@@ -4934,6 +5025,7 @@ static lfs_ssize_t lfs_fs_rawsize(lfs_t *lfs) {
     return size;
 }
 
+
 #ifdef LFS_MIGRATE
 ////// Migration from littelfs v1 below this //////
 
@@ -6053,6 +6145,20 @@ int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir) {
     return err;
 }
 
+int lfs_fs_stat(lfs_t *lfs, struct lfs_fsinfo *fsinfo) {
+    int err = LFS_LOCK(lfs->cfg);
+    if (err) {
+        return err;
+    }
+    LFS_TRACE("lfs_fs_stat(%p, %p)", (void*)lfs, (void*)fsinfo);
+
+    err = lfs_fs_rawstat(lfs, fsinfo);
+
+    LFS_TRACE("lfs_fs_stat -> %d", err);
+    LFS_UNLOCK(lfs->cfg);
+    return err;
+}
+
 lfs_ssize_t lfs_fs_size(lfs_t *lfs) {
     int err = LFS_LOCK(lfs->cfg);
     if (err) {
diff --git a/lfs.h b/lfs.h
index eb5c355..1081735 100644
--- 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 0x00020006
+#define LFS_VERSION 0x00020007
 #define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
 #define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >>  0))
 
@@ -263,6 +263,14 @@ struct lfs_config {
     // can help bound the metadata compaction time. Must be <= block_size.
     // Defaults to block_size when zero.
     lfs_size_t metadata_max;
+
+#ifdef LFS_MULTIVERSION
+    // On-disk version to use when writing in the form of 16-bit major version
+    // + 16-bit minor version. This limiting metadata to what is supported by
+    // older minor versions. Note that some features will be lost. Defaults to 
+    // to the most recent minor version when zero.
+    uint32_t disk_version;
+#endif
 };
 
 // File info structure
@@ -280,6 +288,21 @@ struct lfs_info {
     char name[LFS_NAME_MAX+1];
 };
 
+// Filesystem info structure
+struct lfs_fsinfo {
+    // On-disk version.
+    uint32_t disk_version;
+
+    // Upper limit on the length of file names in bytes.
+    lfs_size_t name_max;
+
+    // Upper limit on the size of files in bytes.
+    lfs_size_t file_max;
+
+    // Upper limit on the size of custom attributes in bytes.
+    lfs_size_t attr_max;
+};
+
 // Custom attribute structure, used to describe custom attributes
 // committed atomically during file writes.
 struct lfs_attr {
@@ -659,6 +682,12 @@ int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir);
 
 /// Filesystem-level filesystem operations
 
+// Find on-disk info about the filesystem
+//
+// Fills out the fsinfo structure based on the filesystem found on-disk.
+// Returns a negative error code on failure.
+int lfs_fs_stat(lfs_t *lfs, struct lfs_fsinfo *fsinfo);
+
 // Finds the current size of the filesystem
 //
 // Note: Result is best effort. If files share COW structures, the returned
diff --git a/runners/test_runner.c b/runners/test_runner.c
index abc867c..27f8524 100644
--- a/runners/test_runner.c
+++ b/runners/test_runner.c
@@ -1346,6 +1346,9 @@ static void run_powerloss_none(
         .block_cycles       = BLOCK_CYCLES,
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
+    #ifdef LFS_MULTIVERSION
+        .disk_version       = DISK_VERSION,
+    #endif
     };
 
     struct lfs_emubd_config bdcfg = {
@@ -1415,6 +1418,9 @@ static void run_powerloss_linear(
         .block_cycles       = BLOCK_CYCLES,
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
+    #ifdef LFS_MULTIVERSION
+        .disk_version       = DISK_VERSION,
+    #endif
     };
 
     struct lfs_emubd_config bdcfg = {
@@ -1501,6 +1507,9 @@ static void run_powerloss_log(
         .block_cycles       = BLOCK_CYCLES,
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
+    #ifdef LFS_MULTIVERSION
+        .disk_version       = DISK_VERSION,
+    #endif
     };
 
     struct lfs_emubd_config bdcfg = {
@@ -1585,6 +1594,9 @@ static void run_powerloss_cycles(
         .block_cycles       = BLOCK_CYCLES,
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
+    #ifdef LFS_MULTIVERSION
+        .disk_version       = DISK_VERSION,
+    #endif
     };
 
     struct lfs_emubd_config bdcfg = {
@@ -1767,6 +1779,9 @@ static void run_powerloss_exhaustive(
         .block_cycles       = BLOCK_CYCLES,
         .cache_size         = CACHE_SIZE,
         .lookahead_size     = LOOKAHEAD_SIZE,
+    #ifdef LFS_MULTIVERSION
+        .disk_version       = DISK_VERSION,
+    #endif
     };
 
     struct lfs_emubd_config bdcfg = {
diff --git a/runners/test_runner.h b/runners/test_runner.h
index 9ff1f79..e30d492 100644
--- a/runners/test_runner.h
+++ b/runners/test_runner.h
@@ -91,6 +91,7 @@ intmax_t test_define(size_t define);
 #define ERASE_CYCLES_i       8
 #define BADBLOCK_BEHAVIOR_i  9
 #define POWERLOSS_BEHAVIOR_i 10
+#define DISK_VERSION_i       11
 
 #define READ_SIZE           TEST_DEFINE(READ_SIZE_i)
 #define PROG_SIZE           TEST_DEFINE(PROG_SIZE_i)
@@ -103,6 +104,7 @@ intmax_t test_define(size_t define);
 #define ERASE_CYCLES        TEST_DEFINE(ERASE_CYCLES_i)
 #define BADBLOCK_BEHAVIOR   TEST_DEFINE(BADBLOCK_BEHAVIOR_i)
 #define POWERLOSS_BEHAVIOR  TEST_DEFINE(POWERLOSS_BEHAVIOR_i)
+#define DISK_VERSION        TEST_DEFINE(DISK_VERSION_i)
 
 #define TEST_IMPLICIT_DEFINES \
     TEST_DEF(READ_SIZE,          PROG_SIZE) \
@@ -115,9 +117,10 @@ intmax_t test_define(size_t define);
     TEST_DEF(ERASE_VALUE,        0xff) \
     TEST_DEF(ERASE_CYCLES,       0) \
     TEST_DEF(BADBLOCK_BEHAVIOR,  LFS_EMUBD_BADBLOCK_PROGERROR) \
-    TEST_DEF(POWERLOSS_BEHAVIOR, LFS_EMUBD_POWERLOSS_NOOP)
+    TEST_DEF(POWERLOSS_BEHAVIOR, LFS_EMUBD_POWERLOSS_NOOP) \
+    TEST_DEF(DISK_VERSION,       0)
 
-#define TEST_IMPLICIT_DEFINE_COUNT 11
+#define TEST_IMPLICIT_DEFINE_COUNT 12
 #define TEST_GEOMETRY_DEFINE_COUNT 4
 
 
diff --git a/tests/test_compat.toml b/tests/test_compat.toml
index a36c38a..ba44714 100644
--- a/tests/test_compat.toml
+++ b/tests/test_compat.toml
@@ -22,14 +22,16 @@ code = '''
 #define STRINGIZE_(x) #x
 #include STRINGIZE(LFSP)
 #else
-#define LFSP_VERSION LFS_VERSION
-#define LFSP_VERSION_MAJOR LFS_VERSION_MAJOR
-#define LFSP_VERSION_MINOR LFS_VERSION_MINOR
+#define LFSP_DISK_VERSION LFS_DISK_VERSION
+#define LFSP_DISK_VERSION_MAJOR LFS_DISK_VERSION_MAJOR
+#define LFSP_DISK_VERSION_MINOR LFS_DISK_VERSION_MINOR
 #define lfsp_t lfs_t
 #define lfsp_config lfs_config
 #define lfsp_format lfs_format
 #define lfsp_mount lfs_mount
 #define lfsp_unmount lfs_unmount
+#define lfsp_fsinfo lfs_fsinfo
+#define lfsp_fs_stat lfs_fs_stat
 #define lfsp_dir_t lfs_dir_t
 #define lfsp_info lfs_info
 #define LFSP_TYPE_REG LFS_TYPE_REG
@@ -58,7 +60,10 @@ code = '''
 
 # test we can mount in a new version
 [cases.test_compat_forward_mount]
-if = 'LFS_VERSION_MAJOR == LFSP_VERSION_MAJOR'
+if = '''
+    LFS_DISK_VERSION_MAJOR == LFSP_DISK_VERSION_MAJOR
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     struct lfsp_config cfgp;
@@ -74,13 +79,22 @@ code = '''
     // now test the new mount
     lfs_t lfs;
     lfs_mount(&lfs, cfg) => 0;
+
+    // we should be able to read the version using lfs_fs_stat
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFSP_DISK_VERSION);
+
     lfs_unmount(&lfs) => 0;
 '''
 
 # test we can read dirs in a new version
 [cases.test_compat_forward_read_dirs]
 defines.COUNT = 5
-if = 'LFS_VERSION_MAJOR == LFSP_VERSION_MAJOR'
+if = '''
+    LFS_DISK_VERSION_MAJOR == LFSP_DISK_VERSION_MAJOR
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     struct lfsp_config cfgp;
@@ -102,6 +116,11 @@ code = '''
     lfs_t lfs;
     lfs_mount(&lfs, cfg) => 0;
 
+    // we should be able to read the version using lfs_fs_stat
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFSP_DISK_VERSION);
+
     // can we list the directories?
     lfs_dir_t dir;
     lfs_dir_open(&lfs, &dir, "/") => 0;
@@ -132,7 +151,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 4
-if = 'LFS_VERSION_MAJOR == LFSP_VERSION_MAJOR'
+if = '''
+    LFS_DISK_VERSION_MAJOR == LFSP_DISK_VERSION_MAJOR
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     struct lfsp_config cfgp;
@@ -166,6 +188,11 @@ code = '''
     lfs_t lfs;
     lfs_mount(&lfs, cfg) => 0;
 
+    // we should be able to read the version using lfs_fs_stat
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFSP_DISK_VERSION);
+
     // can we list the files?
     lfs_dir_t dir;
     lfs_dir_open(&lfs, &dir, "/") => 0;
@@ -214,7 +241,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 4
-if = 'LFS_VERSION_MAJOR == LFSP_VERSION_MAJOR'
+if = '''
+    LFS_DISK_VERSION_MAJOR == LFSP_DISK_VERSION_MAJOR
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     struct lfsp_config cfgp;
@@ -251,6 +281,11 @@ code = '''
     lfs_t lfs;
     lfs_mount(&lfs, cfg) => 0;
 
+    // we should be able to read the version using lfs_fs_stat
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFSP_DISK_VERSION);
+
     // can we list the directories?
     lfs_dir_t dir;
     lfs_dir_open(&lfs, &dir, "/") => 0;
@@ -321,7 +356,10 @@ code = '''
 # test we can write dirs in a new version
 [cases.test_compat_forward_write_dirs]
 defines.COUNT = 10
-if = 'LFS_VERSION_MAJOR == LFSP_VERSION_MAJOR'
+if = '''
+    LFS_DISK_VERSION_MAJOR == LFSP_DISK_VERSION_MAJOR
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     struct lfsp_config cfgp;
@@ -343,6 +381,11 @@ code = '''
     lfs_t lfs;
     lfs_mount(&lfs, cfg) => 0;
 
+    // we should be able to read the version using lfs_fs_stat
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFSP_DISK_VERSION);
+
     // write another COUNT/2 dirs
     for (lfs_size_t i = COUNT/2; i < COUNT; i++) {
         char name[8];
@@ -380,7 +423,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 2
-if = 'LFS_VERSION_MAJOR == LFSP_VERSION_MAJOR'
+if = '''
+    LFS_DISK_VERSION_MAJOR == LFSP_DISK_VERSION_MAJOR
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     struct lfsp_config cfgp;
@@ -420,6 +466,11 @@ code = '''
     lfs_t lfs;
     lfs_mount(&lfs, cfg) => 0;
 
+    // we should be able to read the version using lfs_fs_stat
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFSP_DISK_VERSION);
+
     // write half COUNT files
     prng = 42;
     for (lfs_size_t i = 0; i < COUNT; i++) {
@@ -494,7 +545,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 2
-if = 'LFS_VERSION_MAJOR == LFSP_VERSION_MAJOR'
+if = '''
+    LFS_DISK_VERSION_MAJOR == LFSP_DISK_VERSION_MAJOR
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     struct lfsp_config cfgp;
@@ -537,6 +591,11 @@ code = '''
     lfs_t lfs;
     lfs_mount(&lfs, cfg) => 0;
 
+    // we should be able to read the version using lfs_fs_stat
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFSP_DISK_VERSION);
+
     // write half COUNT files
     prng = 42;
     for (lfs_size_t i = 0; i < COUNT; i++) {
@@ -636,7 +695,10 @@ code = '''
 
 # test we can mount in an old version
 [cases.test_compat_backward_mount]
-if = 'LFS_VERSION == LFSP_VERSION'
+if = '''
+    LFS_DISK_VERSION == LFSP_DISK_VERSION
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the new version
     lfs_t lfs;
@@ -651,13 +713,17 @@ code = '''
     memcpy(&cfgp, cfg, sizeof(cfgp));
     lfsp_t lfsp;
     lfsp_mount(&lfsp, &cfgp) => 0;
+
     lfsp_unmount(&lfsp) => 0;
 '''
 
 # test we can read dirs in an old version
 [cases.test_compat_backward_read_dirs]
 defines.COUNT = 5
-if = 'LFS_VERSION == LFSP_VERSION'
+if = '''
+    LFS_DISK_VERSION == LFSP_DISK_VERSION
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the new version
     lfs_t lfs;
@@ -709,7 +775,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 4
-if = 'LFS_VERSION == LFSP_VERSION'
+if = '''
+    LFS_DISK_VERSION == LFSP_DISK_VERSION
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the new version
     lfs_t lfs;
@@ -791,7 +860,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 4
-if = 'LFS_VERSION == LFSP_VERSION'
+if = '''
+    LFS_DISK_VERSION == LFSP_DISK_VERSION
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the new version
     lfs_t lfs;
@@ -898,7 +970,10 @@ code = '''
 # test we can write dirs in an old version
 [cases.test_compat_backward_write_dirs]
 defines.COUNT = 10
-if = 'LFS_VERSION == LFSP_VERSION'
+if = '''
+    LFS_DISK_VERSION == LFSP_DISK_VERSION
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the new version
     lfs_t lfs;
@@ -957,7 +1032,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 2
-if = 'LFS_VERSION == LFSP_VERSION'
+if = '''
+    LFS_DISK_VERSION == LFSP_DISK_VERSION
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     lfs_t lfs;
@@ -1071,7 +1149,10 @@ code = '''
 defines.COUNT = 5
 defines.SIZE = [4, 32, 512, 8192]
 defines.CHUNK = 2
-if = 'LFS_VERSION == LFSP_VERSION'
+if = '''
+    LFS_DISK_VERSION == LFSP_DISK_VERSION
+        && DISK_VERSION == 0
+'''
 code = '''
     // create the previous version
     lfs_t lfs;
@@ -1280,7 +1361,10 @@ code = '''
 # test that we correctly bump the minor version
 [cases.test_compat_minor_bump]
 in = 'lfs.c'
-if = 'LFS_DISK_VERSION_MINOR > 0'
+if = '''
+    LFS_DISK_VERSION_MINOR > 0
+        && DISK_VERSION == 0
+'''
 code = '''
     // create a superblock
     lfs_t lfs;
@@ -1316,45 +1400,54 @@ code = '''
 
     // mount should still work
     lfs_mount(&lfs, cfg) => 0;
+
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION-1);
+
     lfs_file_open(&lfs, &file, "test", LFS_O_RDONLY) => 0;
     uint8_t buffer[8];
     lfs_file_read(&lfs, &file, buffer, 8) => 8;
     assert(memcmp(buffer, "testtest", 8) == 0);
     lfs_file_close(&lfs, &file) => 0;
+
+    // minor version should be unchanged
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION-1);
+
     lfs_unmount(&lfs) => 0;
 
     // if we write, we need to bump the minor version
     lfs_mount(&lfs, cfg) => 0;
+
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION-1);
+
     lfs_file_open(&lfs, &file, "test", LFS_O_WRONLY | LFS_O_TRUNC) => 0;
     lfs_file_write(&lfs, &file, "teeeeest", 8) => 8;
     lfs_file_close(&lfs, &file) => 0;
 
-    // minor version should have changed
-    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_INLINESTRUCT, 0, sizeof(superblock)),
-            &superblock)
-            => LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock));
-    lfs_superblock_fromle32(&superblock);
-    assert((superblock.version >> 16) & 0xffff == LFS_DISK_VERSION_MAJOR);
-    assert((superblock.version >>  0) & 0xffff == LFS_DISK_VERSION_MINOR);
+    // minor version should be changed
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION);
+
     lfs_unmount(&lfs) => 0;
 
     // and of course mount should still work
     lfs_mount(&lfs, cfg) => 0;
+
+    // minor version should have changed
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION);
+
     lfs_file_open(&lfs, &file, "test", LFS_O_RDONLY) => 0;
     lfs_file_read(&lfs, &file, buffer, 8) => 8;
     assert(memcmp(buffer, "teeeeest", 8) == 0);
     lfs_file_close(&lfs, &file) => 0;
 
-    // minor version should have changed
-    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_INLINESTRUCT, 0, sizeof(superblock)),
-            &superblock)
-            => LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock));
-    lfs_superblock_fromle32(&superblock);
-    assert((superblock.version >> 16) & 0xffff == LFS_DISK_VERSION_MAJOR);
-    assert((superblock.version >>  0) & 0xffff == LFS_DISK_VERSION_MINOR);
+    // yep, still changed
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION);
+
     lfs_unmount(&lfs) => 0;
 '''
diff --git a/tests/test_powerloss.toml b/tests/test_powerloss.toml
index 06f8661..92c323b 100644
--- a/tests/test_powerloss.toml
+++ b/tests/test_powerloss.toml
@@ -90,7 +90,10 @@ code = '''
 
 # partial prog, may not be byte in order!
 [cases.test_powerloss_partial_prog]
-if = "PROG_SIZE < BLOCK_SIZE"
+if = '''
+    PROG_SIZE < BLOCK_SIZE
+        && (DISK_VERSION == 0 || DISK_VERSION >= 0x00020001)
+'''
 defines.BYTE_OFF = ["0", "PROG_SIZE-1", "PROG_SIZE/2"]
 defines.BYTE_VALUE = [0x33, 0xcc]
 in = "lfs.c"
diff --git a/tests/test_superblocks.toml b/tests/test_superblocks.toml
index 689bbcd..0aff84b 100644
--- a/tests/test_superblocks.toml
+++ b/tests/test_superblocks.toml
@@ -34,6 +34,54 @@ code = '''
     lfs_mount(&lfs, cfg) => LFS_ERR_CORRUPT;
 '''
 
+# test we can read superblock info through lfs_fs_stat
+[cases.test_superblocks_stat]
+if = 'DISK_VERSION == 0'
+code = '''
+    lfs_t lfs;
+    lfs_format(&lfs, cfg) => 0;
+
+    // test we can mount and read fsinfo
+    lfs_mount(&lfs, cfg) => 0;
+
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION);
+    assert(fsinfo.name_max == LFS_NAME_MAX);
+    assert(fsinfo.file_max == LFS_FILE_MAX);
+    assert(fsinfo.attr_max == LFS_ATTR_MAX);
+
+    lfs_unmount(&lfs) => 0;
+'''
+
+[cases.test_superblocks_stat_tweaked]
+if = 'DISK_VERSION == 0'
+defines.TWEAKED_NAME_MAX = 63
+defines.TWEAKED_FILE_MAX = '(1 << 16)-1'
+defines.TWEAKED_ATTR_MAX = 512
+code = '''
+    // create filesystem with tweaked params
+    struct lfs_config tweaked_cfg = *cfg;
+    tweaked_cfg.name_max = TWEAKED_NAME_MAX;
+    tweaked_cfg.file_max = TWEAKED_FILE_MAX;
+    tweaked_cfg.attr_max = TWEAKED_ATTR_MAX;
+
+    lfs_t lfs;
+    lfs_format(&lfs, &tweaked_cfg) => 0;
+
+    // test we can mount and read these params with the original config
+    lfs_mount(&lfs, cfg) => 0;
+
+    struct lfs_fsinfo fsinfo;
+    lfs_fs_stat(&lfs, &fsinfo) => 0;
+    assert(fsinfo.disk_version == LFS_DISK_VERSION);
+    assert(fsinfo.name_max == TWEAKED_NAME_MAX);
+    assert(fsinfo.file_max == TWEAKED_FILE_MAX);
+    assert(fsinfo.attr_max == TWEAKED_ATTR_MAX);
+
+    lfs_unmount(&lfs) => 0;
+'''
+
 # expanding superblock
 [cases.test_superblocks_expand]
 defines.BLOCK_CYCLES = [32, 33, 1]

From 96163855a518c95692bf792efbb73c27af653b48 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 3 Jul 2023 11:07:48 -0500
Subject: [PATCH 02/12] Update copyright notice

---
 LICENSE.md    | 1 +
 lfs_fuse.c    | 1 +
 lfs_fuse_bd.c | 1 +
 lfs_fuse_bd.h | 1 +
 4 files changed, 4 insertions(+)

diff --git a/LICENSE.md b/LICENSE.md
index ed69bea..3c97553 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -1,3 +1,4 @@
+Copyright (c) 2022, the littlefs authors.
 Copyright (c) 2017, Arm Limited. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification,
diff --git a/lfs_fuse.c b/lfs_fuse.c
index 3c87dad..3fcb51b 100644
--- a/lfs_fuse.c
+++ b/lfs_fuse.c
@@ -1,6 +1,7 @@
 /*
  * FUSE wrapper for the littlefs
  *
+ * Copyright (c) 2022, the littlefs authors.
  * Copyright (c) 2017, Arm Limited. All rights reserved.
  * SPDX-License-Identifier: BSD-3-Clause
  */
diff --git a/lfs_fuse_bd.c b/lfs_fuse_bd.c
index 9859c32..952825b 100644
--- a/lfs_fuse_bd.c
+++ b/lfs_fuse_bd.c
@@ -1,6 +1,7 @@
 /*
  * Linux user-space block device wrapper
  *
+ * Copyright (c) 2022, the littlefs authors.
  * Copyright (c) 2017, Arm Limited. All rights reserved.
  * SPDX-License-Identifier: BSD-3-Clause
  */
diff --git a/lfs_fuse_bd.h b/lfs_fuse_bd.h
index 07197b2..5465c84 100644
--- a/lfs_fuse_bd.h
+++ b/lfs_fuse_bd.h
@@ -1,6 +1,7 @@
 /*
  * Linux user-space block device wrapper
  *
+ * Copyright (c) 2022, the littlefs authors.
  * Copyright (c) 2017, Arm Limited. All rights reserved.
  * SPDX-License-Identifier: BSD-3-Clause
  */

From 3e6041a59977a6652504d22798eb42f52859aeb9 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 3 Jul 2023 11:22:49 -0500
Subject: [PATCH 03/12] Added a littlefs-fuse specific version number

Previously this was fixed to the underlying littlefs core version, but
that state of things doesn't work if you ever want new features in
littelfs-fuse outside of littlefs minor releases.

This currently matches the underlying core minor version, to tie things
together, but will fall out of sync as things are updated.
---
 lfs_fuse.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/lfs_fuse.c b/lfs_fuse.c
index 3c87dad..696e794 100644
--- a/lfs_fuse.c
+++ b/lfs_fuse.c
@@ -25,6 +25,18 @@
 #include <errno.h>
 
 
+// littefs-fuse version
+//
+// Note this is different from the littlefs core version, and littlefs
+// on-disk version
+//
+// Major (top-nibble), incremented on backwards incompatible changes
+// Minor (bottom-nibble), incremented on feature additions
+#define LFS_FUSE_VERSION 0x00020006
+#define LFS_FUSE_VERSION_MAJOR (0xffff & (LFS_FUSE_VERSION >> 16))
+#define LFS_FUSE_VERSION_MINOR (0xffff & (LFS_FUSE_VERSION >>  0))
+
+
 // config and other state
 static struct lfs_config config = {0};
 static const char *device = NULL;
@@ -467,10 +479,12 @@ int lfs_fuse_opt_proc(void *data, const char *arg,
             exit(1);
             
         case KEY_VERSION:
+            fprintf(stderr, "littlefs-fuse version: v%d.%d\n",
+                LFS_FUSE_VERSION_MAJOR, LFS_FUSE_VERSION_MINOR);
             fprintf(stderr, "littlefs version: v%d.%d\n",
-                 LFS_VERSION_MAJOR, LFS_VERSION_MINOR);
+                LFS_VERSION_MAJOR, LFS_VERSION_MINOR);
             fprintf(stderr, "littlefs disk version: v%d.%d\n",
-                 LFS_DISK_VERSION_MAJOR, LFS_DISK_VERSION_MINOR);
+                LFS_DISK_VERSION_MAJOR, LFS_DISK_VERSION_MINOR);
             fuse_opt_add_arg(args, "--version");
             fuse_main(args->argc, args->argv, &lfs_fuse_ops, NULL);
             exit(0);

From 6096245af895cf3693fec163a6dfe8dbfe71e640 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 3 Jul 2023 11:34:00 -0500
Subject: [PATCH 04/12] Added GitHub Action to test littlefs-fuse, removed
 .travis.yml

Based on GitHub Action script in the core littlefs repo.
---
 .github/workflows/test.yml | 50 +++++++++++++++++++++
 .travis.yml                | 90 --------------------------------------
 2 files changed, 50 insertions(+), 90 deletions(-)
 create mode 100644 .github/workflows/test.yml
 delete mode 100644 .travis.yml

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..95b9251
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,50 @@
+name: test
+on: [push, pull_request]
+
+defaults:
+  run:
+    shell: bash -euv -o pipefail {0}
+
+env:
+  CFLAGS: -Werror
+  MAKEFLAGS: -j
+
+jobs:
+  # self-host test with littlefs-fuse
+  test:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v2
+      - name: install
+        run: |
+          # need a few things
+          sudo apt-get update -qq
+          sudo apt-get install -qq gcc python3 python3-pip libfuse-dev
+          sudo pip3 install toml
+          gcc --version
+          python3 --version
+          fusermount -V
+      - name: setup
+        run: |
+          # setup disk for littlefs-fuse
+          mkdir mount
+          LOOP=$(sudo losetup -f)
+          sudo chmod a+rw $LOOP
+          dd if=/dev/zero bs=512 count=128K of=disk
+          losetup $LOOP disk
+          echo "LOOP=$LOOP" >> $GITHUB_ENV
+      - name: test
+        run: |
+          # self-host test
+          make
+
+          ./lfs --format $LOOP
+          ./lfs $LOOP mount
+
+          ls mount
+          cp -r littlefs mount/littlefs
+          cd mount/littlefs
+          stat .
+          ls -flh
+          make -B test-runner
+          make -B test
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 93c107e..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,90 +0,0 @@
-# Environment variables
-env:
-  global:
-    - CFLAGS=-Werror
-
-cache:
-  pip: true
-  directories:
-    - $HOME/.cache/apt
-
-# CI Jobs
-jobs:
-  include:
-    # Test stage
-    - stage: test
-      env:
-        - STAGE=test
-      install:
-        - sudo apt-get install python3 python3-pip
-        - sudo pip3 install toml
-        - sudo apt-get install libfuse-dev
-        - fusermount -V
-        - gcc --version
-      before_script:
-        - mkdir mount
-        - sudo chmod a+rw /dev/loop0
-        - dd if=/dev/zero bs=512 count=128K of=disk
-        - losetup /dev/loop0 disk
-      script:
-        # Build
-        - make
-        # Format and mount
-        - ./lfs --format /dev/loop0
-        - ./lfs /dev/loop0 mount
-        # Some simple operations than self hosting test
-        - ls mount
-        - cp -r littlefs mount/littlefs
-        - cd mount/littlefs
-        - stat .
-        - ls -flh
-        - make -B test
-
-    # Deploy stage for updating versions and tags
-    - stage: deploy
-      env:
-        - STAGE=deploy
-      script:
-        - |
-          bash << 'SCRIPT'
-          set -ev
-          # Find version defined in lfs.h
-          LFS_VERSION=$(grep -ox '#define LFS_VERSION .*' littlefs/lfs.h | cut -d ' ' -f3)
-          LFS_VERSION_MAJOR=$((0xffff & ($LFS_VERSION >> 16)))
-          LFS_VERSION_MINOR=$((0xffff & ($LFS_VERSION >>  0)))
-          # Grab latest 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 (vN)
-          git branch v$LFS_VERSION_MAJOR HEAD
-          git push https://$GEKY_BOT_RELEASES@github.com/$TRAVIS_REPO_SLUG.git \
-              v$LFS_VERSION_MAJOR
-          # Create patch version tag (vN.N.N)
-          curl -f -u "$GEKY_BOT_RELEASES" -X POST \
-              https://api.github.com/repos/$TRAVIS_REPO_SLUG/git/refs \
-              -d "{
-                  \"ref\": \"refs/tags/$LFS_VERSION\",
-                  \"sha\": \"$TRAVIS_COMMIT\"
-              }"
-          SCRIPT
-
-# Job control
-stages:
-  - name: test
-  - name: deploy
-    if: branch = master AND type = push

From f4606307d47868eb7d2a136cc44fb504f155e73a Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 3 Jul 2023 11:56:29 -0500
Subject: [PATCH 05/12] Added GitHub Action release script

On passing tests on master:

1. Update "vN" branch
2. Create release notes containing all non-merge commits
3. If patch release, publish release
4. If >=minor release, create draft release but let a human publish

This is based on the current release script in the core littlefs repo.
---
 .github/workflows/release.yml | 109 ++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 .github/workflows/release.yml

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000..a49c75c
--- /dev/null
+++ b/.github/workflows/release.yml
@@ -0,0 +1,109 @@
+name: release
+on:
+  workflow_run:
+    workflows: [test]
+    branches: [master]
+    types: [completed]
+
+defaults:
+  run:
+    shell: bash -euv -o pipefail {0}
+
+jobs:
+  release:
+    runs-on: ubuntu-22.04
+
+    # need to manually check for a couple things
+    # - tests passed?
+    # - we are the most recent commit on master?
+    if: ${{github.event.workflow_run.conclusion == 'success' &&
+      github.event.workflow_run.head_sha == github.sha}}
+
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          ref: ${{github.event.workflow_run.head_sha}}
+          # need workflow access since we push branches
+          # containing workflows
+          token: ${{secrets.BOT_TOKEN}}
+          # need all tags
+          fetch-depth: 0
+
+      - name: find-version
+        run: |
+          # rip version from lfs_fuse.c
+          LFS_FUSE_VERSION="$( \
+            grep -o '^#define LFS_FUSE_VERSION .*$' lfs_fuse.c \
+            | awk '{print $3}')"
+          LFS_FUSE_VERSION_MAJOR="$((0xffff & ($LFS_FUSE_VERSION >> 16)))"
+          LFS_FUSE_VERSION_MINOR="$((0xffff & ($LFS_FUSE_VERSION >>  0)))"
+
+          # find a new patch version based on what we find in our tags
+          LFS_FUSE_VERSION_PATCH="$( \
+            ( git describe --tags --abbrev=0 \
+                --match="v$LFS_FUSE_VERSION_MAJOR.$LFS_FUSE_VERSION_MINOR.*" \
+              || echo 'v0.0.-1' ) \
+            | awk -F '.' '{print $3+1}')"
+
+          # found new version
+          LFS_FUSE_VERSION="v$LFS_FUSE_VERSION_MAJOR`
+            `.$LFS_FUSE_VERSION_MINOR`
+            `.$LFS_FUSE_VERSION_PATCH"
+          echo "LFS_FUSE_VERSION=$LFS_FUSE_VERSION"
+          echo "LFS_FUSE_VERSION=$LFS_FUSE_VERSION" >> $GITHUB_ENV
+          echo "LFS_FUSE_VERSION_MAJOR=$LFS_FUSE_VERSION_MAJOR" >> $GITHUB_ENV
+          echo "LFS_FUSE_VERSION_MINOR=$LFS_FUSE_VERSION_MINOR" >> $GITHUB_ENV
+          echo "LFS_FUSE_VERSION_PATCH=$LFS_FUSE_VERSION_PATCH" >> $GITHUB_ENV
+
+      # try to find previous version?
+      - name: find-prev-version
+        continue-on-error: true
+        run: |
+          LFS_FUSE_PREV_VERSION="$( \
+            git describe --tags --abbrev=0 --match 'v*' \
+            || true)"
+          echo "LFS_FUSE_PREV_VERSION=$LFS_FUSE_PREV_VERSION"
+          echo "LFS_FUSE_PREV_VERSION=$LFS_FUSE_PREV_VERSION" >> $GITHUB_ENV
+
+      # find changes from history
+      - name: create-changes
+        run: |
+          [ -n "$LFS_FUSE_PREV_VERSION" ] || exit 0
+          # use explicit link to github commit so that release notes can
+          # be copied elsewhere
+          git log "$LFS_FUSE_PREV_VERSION.." \
+            --grep='^Merge' --invert-grep \
+            --format="format:[\`%h\`](`
+              `https://github.com/$GITHUB_REPOSITORY/commit/%h) %s" \
+            > changes.txt
+          echo "CHANGES:"
+          cat changes.txt
+
+      # create and update major branches (vN)
+      - name: create-major-branches
+        run: |
+          # create major branch
+          git branch "v$LFS_FUSE_VERSION_MAJOR" HEAD
+
+          # push!
+          git push --atomic origin "v$LFS_FUSE_VERSION_MAJOR"
+
+      # build release notes
+      - name: create-release
+        run: |
+          # create release and patch version tag (vN.N.N)
+          # only draft if not a patch release
+          touch release.txt
+          [ -e changes.txt ] && cat changes.txt >> release.txt
+          cat release.txt
+
+          curl -sS -X POST -H "authorization: token ${{secrets.BOT_TOKEN}}" \
+            "$GITHUB_API_URL/repos/$GITHUB_REPOSITORY/releases" \
+            -d "$(jq -n --rawfile release release.txt '{
+              tag_name: env.LFS_FUSE_VERSION,
+              name: env.LFS_FUSE_VERSION | rtrimstr(".0"),
+              target_commitish: "${{github.event.workflow_run.head_sha}}",
+              draft: env.LFS_FUSE_VERSION | endswith(".0"),
+              body: $release,
+            }' | tee /dev/stderr)"
+

From 1a7881cd5938a0806511aa50b49b2155464ab373 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 3 Jul 2023 15:25:06 -0500
Subject: [PATCH 06/12] Added some on-disk minor version features

- Integrated lfs_fs_stat into statvfs, so statvfs.namemax reports
  the on-disk name_max correctly.

- Added ./lfs --stat, which allows you to access littlefs-specific info
  without needing to mount the filesystem. Currently this includes:

  - on-disk version
  - block_size (from ioctl)
  - block_count (from ioctl)
  - block usage as both used, free, and percentage, for convenience
  - on-disk name_max
  - on-disk file_max
  - on-disk attr_max

  This may be extended in the future

  Example output:

    $ ./lfs --stat /dev/loop9
    disk_version: lfs2.1
    block_size: 512
    block_count: 131072
      used: 2/131072 (0.0%)
      free: 131070/131072 (100.0%)
    name_max: 255
    file_max: 2147483647
    attr_max: 1022

- Added support for writing previous minor versions of littlefs via the
  --disk_version (-d) flag. Note because of limitations in FUSE's
  argument parser, this requires an equal sign:

    $ ./lfs -d=lfs2.0 --format /dev/loop9
    $ ./lfs --stat /dev/loop9
    disk_version: lfs2.0
    ...
---
 Makefile   |   3 ++
 lfs_fuse.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 149 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index ca73029..c6725a1 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,9 @@ override CFLAGS += -I. -Ilittlefs
 override CFLAGS += -std=c99 -Wall -pedantic
 override CFLAGS += -D_FILE_OFFSET_BITS=64
 override CFLAGS += -D_XOPEN_SOURCE=700
+# enable multiversion support in littlefs
+override CFLAGS += -DLFS_MULTIVERSION
+# enable migrate support in littlefs
 override CFLAGS += -DLFS_MIGRATE
 
 override LFLAGS += -lfuse
diff --git a/lfs_fuse.c b/lfs_fuse.c
index 696e794..675d701 100644
--- a/lfs_fuse.c
+++ b/lfs_fuse.c
@@ -40,6 +40,7 @@
 // config and other state
 static struct lfs_config config = {0};
 static const char *device = NULL;
+static bool stat_ = false;
 static bool format = false;
 static bool migrate = false;
 static lfs_t lfs;
@@ -82,6 +83,59 @@ void *lfs_fuse_init(struct fuse_conn_info *conn) {
     return 0;
 }
 
+int lfs_fuse_stat(void) {
+    int err = lfs_fuse_bd_create(&config, device);
+    if (err) {
+        return err;
+    }
+
+    lfs_fuse_defaults(&config);
+
+    err = lfs_mount(&lfs, &config);
+    if (err) {
+        goto failed;
+    }
+
+    // get on-disk info
+    struct lfs_fsinfo fsinfo;
+    err = lfs_fs_stat(&lfs, &fsinfo);
+    if (err) {
+        goto failed;
+    }
+
+    // get block usage
+    lfs_ssize_t in_use = lfs_fs_size(&lfs);
+    if (in_use < 0) {
+        err = in_use;
+        goto failed;
+    }
+
+    // print to stdout
+    printf("disk_version: lfs%d.%d\n",
+            0xffff & (fsinfo.disk_version >> 16),
+            0xffff & (fsinfo.disk_version >>  0));
+    printf("block_size: %d\n", config.block_size);
+    printf("block_count: %d\n", config.block_count);
+    printf("  used: %d/%d (%.1f%%)\n",
+            in_use,
+            config.block_count,
+            100.0f * (float)in_use / (float)config.block_count);
+    printf("  free: %d/%d (%.1f%%)\n",
+            config.block_count-in_use,
+            config.block_count,
+            100.0f * (float)(config.block_count-in_use)
+                / (float)config.block_count);
+    printf("name_max: %d\n", fsinfo.name_max);
+    printf("file_max: %d\n", fsinfo.file_max);
+    printf("attr_max: %d\n", fsinfo.attr_max);
+
+    err = lfs_unmount(&lfs);
+
+failed:
+    lfs_fuse_bd_destroy(&config);
+    return err;
+}
+
 int lfs_fuse_format(void) {
     int err = lfs_fuse_bd_create(&config, device);
     if (err) {
@@ -129,6 +183,14 @@ void lfs_fuse_destroy(void *eh) {
 int lfs_fuse_statfs(const char *path, struct statvfs *s) {
     memset(s, 0, sizeof(struct statvfs));
 
+    // get the on-disk name_max from littlefs
+    struct lfs_fsinfo fsinfo;
+    int err = lfs_fs_stat(&lfs, &fsinfo);
+    if (err) {
+        return err;
+    }
+
+    // get the filesystem block usage from littlefs
     lfs_ssize_t in_use = lfs_fs_size(&lfs);
     if (in_use < 0) {
         return in_use;
@@ -139,7 +201,7 @@ int lfs_fuse_statfs(const char *path, struct statvfs *s) {
     s->f_blocks = config.block_count;
     s->f_bfree = config.block_count - in_use;
     s->f_bavail = config.block_count - in_use;
-    s->f_namemax = config.name_max;
+    s->f_namemax = fsinfo.name_max;
 
     return 0;
 }
@@ -403,14 +465,19 @@ static struct fuse_operations lfs_fuse_ops = {
 enum lfs_fuse_keys {
     KEY_HELP,
     KEY_VERSION,
+    KEY_STAT,
     KEY_FORMAT,
     KEY_MIGRATE,
+    KEY_DISK_VERSION,
 };
 
 #define OPT(t, p) { t, offsetof(struct lfs_config, p), 0}
 static struct fuse_opt lfs_fuse_opts[] = {
+    FUSE_OPT_KEY("--stat",      KEY_STAT),
     FUSE_OPT_KEY("--format",    KEY_FORMAT),
     FUSE_OPT_KEY("--migrate",   KEY_MIGRATE),
+    {"-d=",                     -1U, KEY_DISK_VERSION},
+    {"--disk_version=",         -1U, KEY_DISK_VERSION},
     OPT("-b=%"                  SCNu32, block_size),
     OPT("--block_size=%"        SCNu32, block_size),
     OPT("--block_count=%"       SCNu32, block_count),
@@ -438,8 +505,10 @@ static const char help_text[] =
 "    -V   --version         print version\n"
 "\n"
 "littlefs options:\n"
+"    --stat                 print filesystem info instead of mounting\n"
 "    --format               format instead of mounting\n"
 "    --migrate              migrate previous version  instead of mounting\n"
+"    -d   --disk_version    attempt to use this on-disk version of littlefs\n"
 "    -b   --block_size      logical block size, overrides the block device\n"
 "    --block_count          block count, overrides the block device\n"
 "    --block_cycles         number of erase cycles before eviction (512)\n"
@@ -464,6 +533,10 @@ int lfs_fuse_opt_proc(void *data, const char *arg,
             }
             break;
 
+        case KEY_STAT:
+            stat_ = true;
+            return 0;
+
         case KEY_FORMAT:
             format = true;
             return 0;
@@ -483,11 +556,72 @@ int lfs_fuse_opt_proc(void *data, const char *arg,
                 LFS_FUSE_VERSION_MAJOR, LFS_FUSE_VERSION_MINOR);
             fprintf(stderr, "littlefs version: v%d.%d\n",
                 LFS_VERSION_MAJOR, LFS_VERSION_MINOR);
-            fprintf(stderr, "littlefs disk version: v%d.%d\n",
+            fprintf(stderr, "littlefs disk version: lfs%d.%d\n",
                 LFS_DISK_VERSION_MAJOR, LFS_DISK_VERSION_MINOR);
             fuse_opt_add_arg(args, "--version");
             fuse_main(args->argc, args->argv, &lfs_fuse_ops, NULL);
             exit(0);
+
+        case KEY_DISK_VERSION: {
+            // skip opt prefix
+            const char *arg_ = strchr(arg, '=');
+            if (arg_) {
+                arg = arg_ + 1;
+            }
+
+            // parse out the requested disk version
+            // supported formats:
+            // - no-prefix       - 2.1
+            // - v-prefix        - v2.1
+            // - lfs-prefix      - lfs2.1
+            // - littlefs-prefix - littlefs2.1
+            const char *orig_arg = arg;
+            if (strlen(arg) >= strlen("v")
+                    && memcmp(arg, "v", strlen("v")) == 0) {
+                arg += strlen("v");
+            } else if (strlen(arg) >= strlen("lfs")
+                    && memcmp(arg, "lfs", strlen("lfs")) == 0) {
+                arg += strlen("lfs");
+            } else if (strlen(arg) >= strlen("littlefs")
+                    && memcmp(arg, "littlefs", strlen("littlefs")) == 0) {
+                arg += strlen("littlefs");
+            }
+
+            char *parsed;
+            uintmax_t major = strtoumax(arg, &parsed, 0);
+            if (parsed == arg) {
+                goto invalid_version;
+            }
+            arg = parsed;
+
+            if (arg[0] != '.') {
+                goto invalid_version;
+            }
+            arg += 1;
+
+            uintmax_t minor = strtoumax(arg, &parsed, 0);
+            if (parsed == arg) {
+                goto invalid_version;
+            }
+            arg = parsed;
+
+            if (arg[0] != '\0') {
+                goto invalid_version;
+            }
+
+            if (major > 0xffff || minor > 0xffff) {
+                goto invalid_version;
+            }
+
+            config.disk_version
+                    = ((major & 0xffff) << 16)
+                    | ((minor & 0xffff) <<  0);
+            return 0;
+
+        invalid_version:
+            fprintf(stderr, "invalid disk version: \"%s\"\n", orig_arg);
+            exit(1);
+        }
     }
 
     return 1;
@@ -502,6 +636,16 @@ int main(int argc, char *argv[]) {
         exit(1);
     }
 
+    if (stat_) {
+        // stat time, no mount
+        int err = lfs_fuse_stat();
+        if (err) {
+            LFS_ERROR("%s", strerror(-err));
+            exit(-err);
+        }
+        exit(0);
+    }
+
     if (format) {
         // format time, no mount
         int err = lfs_fuse_format();

From ec4c8857579243c8ab1423d2947c338f782994a4 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 21 Aug 2023 13:32:03 -0500
Subject: [PATCH 07/12] Added CI testing of minor on-disk features: --stat and
 -d=lfs2.0

---
 .github/workflows/test.yml | 59 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 95b9251..bf1cd95 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -39,6 +39,7 @@ jobs:
           make
 
           ./lfs --format $LOOP
+          ./lfs --stat $LOOP
           ./lfs $LOOP mount
 
           ls mount
@@ -48,3 +49,61 @@ jobs:
           ls -flh
           make -B test-runner
           make -B test
+
+  # test older versions
+  test-lfs2_0:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v2
+      - name: install
+        run: |
+          # need a few things
+          sudo apt-get update -qq
+          sudo apt-get install -qq gcc python3 python3-pip libfuse-dev
+          sudo pip3 install toml
+          gcc --version
+          python3 --version
+          fusermount -V
+      - name: setup
+        run: |
+          # setup disk for littlefs-fuse
+          mkdir mount
+          LOOP=$(sudo losetup -f)
+          sudo chmod a+rw $LOOP
+          dd if=/dev/zero bs=512 count=128K of=disk
+          losetup $LOOP disk
+          echo "LOOP=$LOOP" >> $GITHUB_ENV
+      - name: test
+        run: |
+          # self-host test
+          make
+
+          ./lfs -d=lfs2.0 --format $LOOP
+          ./lfs --stat $LOOP
+          ./lfs -d=lfs2.0 $LOOP mount
+
+          ls mount
+          cp -r littlefs mount/littlefs
+          cd mount/littlefs
+          stat .
+          ls -flh
+          make -B test-runner
+          make -B test
+      - name: test-migrate
+        run: |
+          # self-host test, this time migrating to current version
+          make
+
+          ./lfs -d=lfs2.0 --format $LOOP
+          ./lfs --stat $LOOP
+          ./lfs $LOOP mount
+
+          ls mount
+          cp -r littlefs mount/littlefs
+          cd mount/littlefs
+          stat .
+          ls -flh
+          make -B test-runner
+          make -B test
+
+          ./lfs --stat $LOOP

From 4aa80f5db793521e0065d30e6ad93e6a4bf23ea8 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 21 Aug 2023 13:42:50 -0500
Subject: [PATCH 08/12] Made CI unmount littlefs at the end of each test

Probably should have been doing this before.

This leaves CI in a stable unmounted state between CI steps, which is
necessary for the lfs2.0-migrate test to work.
---
 .github/workflows/test.yml | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bf1cd95..3931a48 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -50,6 +50,10 @@ jobs:
           make -B test-runner
           make -B test
 
+          cd ../..
+          umount mount
+          ./lfs --stat $LOOP
+
   # test older versions
   test-lfs2_0:
     runs-on: ubuntu-22.04
@@ -89,6 +93,10 @@ jobs:
           ls -flh
           make -B test-runner
           make -B test
+
+          cd ../..
+          umount mount
+          ./lfs --stat $LOOP
       - name: test-migrate
         run: |
           # self-host test, this time migrating to current version
@@ -106,4 +114,6 @@ jobs:
           make -B test-runner
           make -B test
 
+          cd ../..
+          umount mount
           ./lfs --stat $LOOP

From e06caf4e9ba0aa0d0323a91acee6b8972a393bad Mon Sep 17 00:00:00 2001
From: taorye <taorye@outlook.com>
Date: Mon, 14 Nov 2022 14:02:11 +0800
Subject: [PATCH 09/12] fix: correct block_count with block_size

BLKGETSIZE means `return device size /512 (long *arg)`
---
 lfs_fuse_bd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lfs_fuse_bd.c b/lfs_fuse_bd.c
index 9859c32..217ef6e 100644
--- a/lfs_fuse_bd.c
+++ b/lfs_fuse_bd.c
@@ -46,7 +46,7 @@ int lfs_fuse_bd_create(struct lfs_config *cfg, const char *path) {
         if (err) {
             return -errno;
         }
-        cfg->block_count = size;
+        cfg->block_count = size * 512 / cfg->block_size;
     }
 
     // setup function pointers

From f448139bdcd9a0f564fe69df28cb74f354825dcb Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 21 Aug 2023 13:37:41 -0500
Subject: [PATCH 10/12] Swapped BLKGETSIZE for BLKGETSIZE64

BLKGETSIZE64 seems to report the size in bytes, which is what we
actually want. BLKGETSIZE reported the size in "512-byte blocks", which
just complicates our final block_count calculation.
---
 lfs_fuse_bd.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lfs_fuse_bd.c b/lfs_fuse_bd.c
index 217ef6e..1422ef1 100644
--- a/lfs_fuse_bd.c
+++ b/lfs_fuse_bd.c
@@ -41,12 +41,12 @@ int lfs_fuse_bd_create(struct lfs_config *cfg, const char *path) {
 
     // get size in sectors
     if (!cfg->block_count) {
-        long size;
-        int err = ioctl(fd, BLKGETSIZE, &size);
+        uint64_t size;
+        int err = ioctl(fd, BLKGETSIZE64, &size);
         if (err) {
             return -errno;
         }
-        cfg->block_count = size * 512 / cfg->block_size;
+        cfg->block_count = size / cfg->block_size;
     }
 
     // setup function pointers

From d5d0a6c6ff629226af249cc1e8b941f670395ed3 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Mon, 21 Aug 2023 23:18:28 -0500
Subject: [PATCH 11/12] Fixed read/write syscalls to continue reading if result
 is less than expected

Found by lucckb
---
 lfs_fuse_bd.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/lfs_fuse_bd.c b/lfs_fuse_bd.c
index 9859c32..ca5a186 100644
--- a/lfs_fuse_bd.c
+++ b/lfs_fuse_bd.c
@@ -66,6 +66,7 @@ void lfs_fuse_bd_destroy(const struct lfs_config *cfg) {
 int lfs_fuse_bd_read(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, void *buffer, lfs_size_t size) {
     int fd = (intptr_t)cfg->context;
+    uint8_t *buffer_ = buffer;
 
     // check if read is valid
     assert(block < cfg->block_count);
@@ -77,9 +78,14 @@ int lfs_fuse_bd_read(const struct lfs_config *cfg, lfs_block_t block,
     }
 
     // read block
-    ssize_t res = read(fd, buffer, (size_t)size);
-    if (res < 0) {
-        return -errno;
+    while (size > 0) {
+        ssize_t res = read(fd, buffer_, (size_t)size);
+        if (res < 0) {
+            return -errno;
+        }
+
+        buffer_ += res;
+        size -= res;
     }
 
     return 0;
@@ -88,6 +94,7 @@ int lfs_fuse_bd_read(const struct lfs_config *cfg, lfs_block_t block,
 int lfs_fuse_bd_prog(const struct lfs_config *cfg, lfs_block_t block,
         lfs_off_t off, const void *buffer, lfs_size_t size) {
     int fd = (intptr_t)cfg->context;
+    const uint8_t *buffer_ = buffer;
 
     // check if write is valid
     assert(block < cfg->block_count);
@@ -99,9 +106,14 @@ int lfs_fuse_bd_prog(const struct lfs_config *cfg, lfs_block_t block,
     }
 
     // write block
-    ssize_t res = write(fd, buffer, (size_t)size);
-    if (res < 0) {
-        return -errno;
+    while (size > 0) {
+        ssize_t res = write(fd, buffer_, (size_t)size);
+        if (res < 0) {
+            return -errno;
+        }
+
+        buffer_ += res;
+        size -= res;
     }
 
     return 0;

From 9ac0820023768c0b49702e06964e2f6765c04cea Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Wed, 23 Aug 2023 00:13:08 -0500
Subject: [PATCH 12/12] Bumped minor version to v2.7

---
 lfs_fuse.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lfs_fuse.c b/lfs_fuse.c
index 3bf101a..7aceb2b 100644
--- a/lfs_fuse.c
+++ b/lfs_fuse.c
@@ -33,7 +33,7 @@
 //
 // Major (top-nibble), incremented on backwards incompatible changes
 // Minor (bottom-nibble), incremented on feature additions
-#define LFS_FUSE_VERSION 0x00020006
+#define LFS_FUSE_VERSION 0x00020007
 #define LFS_FUSE_VERSION_MAJOR (0xffff & (LFS_FUSE_VERSION >> 16))
 #define LFS_FUSE_VERSION_MINOR (0xffff & (LFS_FUSE_VERSION >>  0))