WIP added framework for full dynamic wear-leveling

.travis.yml

@@ -19,7 +19,7 @@ script:
 
   # 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"
+  - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=512    -DLFS_CACHE_SIZE=512 -DLFS_BLOCK_CYCLES=16"
   - make test QUIET=1 CFLAGS+="-DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD=2048"
 
   - make clean test QUIET=1 CFLAGS+="-DLFS_INLINE_MAX=0"

lfs.c

@@ -265,6 +265,8 @@ static int32_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]);
+static int lfs_fs_deorphan(lfs_t *lfs);
+static int lfs_fs_demove(lfs_t *lfs);
 static int lfs_fs_forceconsistency(lfs_t *lfs);
 static int lfs_deinit(lfs_t *lfs);
 
@@ -924,7 +926,27 @@ static int32_t lfs_dir_fetchmatch(lfs_t *lfs,
                         tempfoundtag -= LFS_MKTAG(0, 1, 0);
                     }
                 } else if ((tag & findmask) == (findtag & findmask)) {
-                    int res = lfs_bd_cmp(lfs, dir->pair[0], off+sizeof(tag),
+                    // found a match?
+                    if (lfs_tag_type(findtag) == LFS_TYPE_DIRSTRUCT) {
+                        lfs_block_t child[2];
+                        err = lfs_bd_read(lfs, dir->pair[0], off+sizeof(tag),
+                                child, sizeof(child));
+                        if (err < 0) {
+                            if (err == LFS_ERR_CORRUPT) {
+                                dir->erased = false;
+                                break;
+                            }
+                            return err;
+                        }
+
+                        lfs_pair_fromle32(child);
+                        if (lfs_pair_cmp(child,
+                                (const lfs_block_t *)findbuffer) == 0) {
+                            tempfoundtag = tag;
+                        }
+                    } else if (lfs_tag_type(findtag) == LFS_TYPE_NAME) {
+                        int res = lfs_bd_cmp(lfs,
+                                dir->pair[0], off+sizeof(tag),
                                 findbuffer, lfs_tag_size(findtag));
                         if (res < 0) {
                             if (res == LFS_ERR_CORRUPT) {
@@ -935,7 +957,9 @@ static int32_t lfs_dir_fetchmatch(lfs_t *lfs,
                         }
 
                         if (res) {
-                        // found a match
+                            tempfoundtag = tag;
+                        }
+                    } else {
                         tempfoundtag = tag;
                     }
                 }
@@ -1016,8 +1040,6 @@ static int lfs_dir_compact(lfs_t *lfs,
         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]};
-    int16_t ack;
-    bool expanding = false;
     bool relocated = false;
 
     // There's nothing special about our global delta, so feed it back
@@ -1025,11 +1047,16 @@ static int lfs_dir_compact(lfs_t *lfs,
     lfs_global_xor(&lfs->locals, &dir->locals);
     lfs_global_zero(&dir->locals);
 
+    while (true) {
+        // last complete id
+        dir->count = end - begin;
+        int16_t ack = -1;
+        bool exhausted = false;
+
         // increment revision count
         dir->rev += 1;
-
+        if (lfs->cfg->block_cycles && dir->rev % lfs->cfg->block_cycles == 0) {
-    if (lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0 &&
+            if (lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0) {
-            dir->rev % 16 == 0) {
                 // we're writing too much to the superblock, should we expand?
                 lfs_ssize_t res = lfs_fs_size(lfs);
                 if (res < 0) {
@@ -1038,18 +1065,18 @@ static int lfs_dir_compact(lfs_t *lfs,
 
                 // do we have enough space to expand?
                 if (res < lfs->cfg->block_count/2) {
-            expanding = (lfs_pair_cmp(dir->pair, lfs->root) != 0);
+                    LFS_DEBUG("Expanding superblock at rev %"PRIu32, dir->rev);
                     ack = 0;
+                    exhausted = (lfs_pair_cmp(dir->pair, lfs->root) != 0);
                     goto split;
                 }
+            } else {
+                // we're writing too much, time to relocate
+                exhausted = true;
+                goto relocate;
+            }
         }
 
-    while (true) {
-        // last complete id
-        ack = -1;
-        dir->count = end - begin;
-
-        if (true) {
         // erase block to write to
         int err = lfs_bd_erase(lfs, dir->pair[1]);
         if (err) {
@@ -1143,7 +1170,6 @@ static int lfs_dir_compact(lfs_t *lfs,
         dir->off = commit.off;
         dir->etag = commit.ptag;
         dir->erased = true;
-        }
         break;
 
 split:
@@ -1157,7 +1183,7 @@ split:
         }
 
         lfs_mdir_t tail;
-        int err = lfs_dir_alloc(lfs, &tail);
+        err = lfs_dir_alloc(lfs, &tail);
         if (err) {
             return err;
         }
@@ -1166,7 +1192,7 @@ split:
         tail.tail[0] = dir->tail[0];
         tail.tail[1] = dir->tail[1];
 
-        err = lfs_dir_compact(lfs, &tail, attrs, source, ack+1-expanding, end);
+        err = lfs_dir_compact(lfs, &tail, attrs, source, ack+1-exhausted, end);
         if (err) {
             return err;
         }
@@ -1178,13 +1204,12 @@ split:
         continue;
 
 relocate:
-        //commit was corrupted
+        // commit was corrupted, drop caches and prepare to relocate block
-        LFS_DEBUG("Bad block at %"PRIu32,
-                dir->pair[1]);
-
-        // drop caches and prepare to relocate block
         relocated = true;
         lfs_cache_drop(lfs, &lfs->pcache);
+        if (!exhausted) {
+            LFS_DEBUG("Bad block at %"PRIu32, dir->pair[1]);
+        }
 
         // can't relocate superblock, filesystem is now frozen
         if (lfs_pair_cmp(oldpair, (const lfs_block_t[2]){0, 1}) == 0) {
@@ -1194,7 +1219,7 @@ relocate:
 
         // relocate half of pair
         err = lfs_alloc(lfs, &dir->pair[1]);
-        if (err) {
+        if (err && (err != LFS_ERR_NOSPC && !exhausted)) {
             return err;
         }
 
@@ -1273,7 +1298,11 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
         }
     }
 
-    if (dir->erased) {
+    while (true) {
+        if (!dir->erased) {
+            goto compact;
+        }
+
         // try to commit
         struct lfs_commit commit = {
             .block = dir->pair[0],
@@ -1332,14 +1361,17 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
         // successful commit, update globals
         lfs_global_xor(&dir->locals, &lfs->locals);
         lfs_global_zero(&lfs->locals);
-    } else {
+        break;
+
 compact:
         // fall back to compaction
         lfs_cache_drop(lfs, &lfs->pcache);
-        int err = lfs_dir_compact(lfs, dir, attrs, dir, 0, dir->count);
+        err = lfs_dir_compact(lfs, dir, attrs, dir, 0, dir->count);
         if (err) {
             return err;
         }
+
+        break;
     }
 
     // update globals that are affected
@@ -1762,7 +1794,6 @@ static int lfs_ctz_extend(lfs_t *lfs,
         }
         LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);
 
-        if (true) {
         err = lfs_bd_erase(lfs, nblock);
         if (err) {
             if (err == LFS_ERR_CORRUPT) {
@@ -1837,7 +1868,6 @@ static int lfs_ctz_extend(lfs_t *lfs,
         *block = nblock;
         *off = 4*skips;
         return 0;
-        }
 
 relocate:
         LFS_DEBUG("Bad block at %"PRIu32, nblock);
@@ -2205,7 +2235,7 @@ int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
                 type = LFS_TYPE_INLINESTRUCT;
                 buffer = file->cache.buffer;
                 size = file->ctz.size;
-            } else if (lfs_tole32(0x11223344) == 0x11223344) {
+            } else {
                 // update the ctz reference
                 type = LFS_TYPE_CTZSTRUCT;
                 // copy ctz so alloc will work during a relocate
@@ -3148,17 +3178,13 @@ static int32_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t pair[2],
     }
 
     // search for both orderings so we can reuse the find function
-    lfs_block_t child[2] = {pair[0], pair[1]};
-    lfs_pair_tole32(child);
     for (int i = 0; i < 2; i++) {
         int32_t tag = lfs_dir_find(lfs, parent,
                 (const lfs_block_t[2]){0, 1}, true, 0x7fc00fff,
-                LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 0, sizeof(child)), child);
+                LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 0, 8), pair);
         if (tag != LFS_ERR_NOENT) {
             return tag;
         }
-
-        lfs_pair_swap(child);
     }
 
     return LFS_ERR_NOENT;
@@ -3201,7 +3227,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
         }
 
         // clean up bad block, which should now be a desync
-        return lfs_fs_forceconsistency(lfs);
+        return lfs_fs_deorphan(lfs);
     }
 
     // find pred
@@ -3227,11 +3253,7 @@ static int lfs_fs_relocate(lfs_t *lfs,
     return 0;
 }
 
-static int lfs_fs_forceconsistency(lfs_t *lfs) {
+static int lfs_fs_deorphan(lfs_t *lfs) {
-    if (!lfs->globals.s.deorphaned) {
-        LFS_DEBUG("Found orphans %"PRIu32,
-                lfs->globals.s.deorphaned);
-
     // Fix any orphans
     lfs_mdir_t pdir = {.split = true};
     lfs_mdir_t dir = {.tail = {0, 1}};
@@ -3299,11 +3321,12 @@ static int lfs_fs_forceconsistency(lfs_t *lfs) {
         memcpy(&pdir, &dir, sizeof(pdir));
     }
 
-        // mark orphan as fixed
+    // mark orphans as fixed
-        lfs_global_deorphaned(lfs, false);
+    lfs_global_deorphaned(lfs, true);
-    }
+    return 0;
+}
 
-    if (lfs->globals.s.moveid != 0x3ff) {
+static int lfs_fs_demove(lfs_t *lfs) {
     // Fix bad moves
     LFS_DEBUG("Fixing move %"PRIu32" %"PRIu32" %"PRIu32,
             lfs->globals.s.movepair[0],
@@ -3322,6 +3345,23 @@ static int lfs_fs_forceconsistency(lfs_t *lfs) {
     if (err) {
         return err;
     }
+
+    return 0;
+}
+
+static int lfs_fs_forceconsistency(lfs_t *lfs) {
+    if (!lfs->globals.s.deorphaned) {
+        int err = lfs_fs_deorphan(lfs);
+        if (err) {
+            return err;
+        }
+    }
+
+    if (lfs->globals.s.moveid != 0x3ff) {
+        int err = lfs_fs_demove(lfs);
+        if (err) {
+            return err;
+        }
     }
 
     return 0;

lfs.h

@@ -178,12 +178,6 @@ struct lfs_config {
     // multiple of this value.
     lfs_size_t prog_size;
 
-    // Size of block caches. Each cache buffers a portion of a block in RAM.
-    // This determines the size of the read cache, the program cache, and a
-    // cache per file. Larger caches can improve performance by storing more
-    // data. Must be a multiple of the read and program sizes.
-    lfs_size_t cache_size;
-
     // Size of an erasable block. This does not impact ram consumption and
     // may be larger than the physical erase size. However, this should be
     // kept small as each file currently takes up an entire block.
@@ -193,6 +187,17 @@ struct lfs_config {
     // Number of erasable blocks on the device.
     lfs_size_t block_count;
 
+    // Number of erase cycles before we should move data to another block.
+    // May be zero to never move data, in which case no block-level
+    // wear-leveling is performed.
+    uint32_t block_cycles;
+
+    // Size of block caches. Each cache buffers a portion of a block in RAM.
+    // This determines the size of the read cache, the program cache, and a
+    // cache per file. Larger caches can improve performance by storing more
+    // data. Must be a multiple of the read and program sizes.
+    lfs_size_t cache_size;
+
     // Number of blocks to lookahead during block allocation. A larger
     // lookahead reduces the number of passes required to allocate a block.
     // The lookahead buffer requires only 1 bit per block so it can be quite

tests/template.fmt

@@ -69,10 +69,6 @@ uintmax_t test;
 #define LFS_PROG_SIZE LFS_READ_SIZE
 #endif
 
-#ifndef LFS_CACHE_SIZE
-#define LFS_CACHE_SIZE 64
-#endif
-
 #ifndef LFS_BLOCK_SIZE
 #define LFS_BLOCK_SIZE 512
 #endif
@@ -81,6 +77,14 @@ uintmax_t test;
 #define LFS_BLOCK_COUNT 1024
 #endif
 
+#ifndef LFS_BLOCK_CYCLES
+#define LFS_BLOCK_CYCLES 1024
+#endif
+
+#ifndef LFS_CACHE_SIZE
+#define LFS_CACHE_SIZE 64
+#endif
+
 #ifndef LFS_LOOKAHEAD
 #define LFS_LOOKAHEAD 128
 #endif
@@ -94,9 +98,10 @@ const struct lfs_config cfg = {{
 
     .read_size    = LFS_READ_SIZE,
     .prog_size    = LFS_PROG_SIZE,
-    .cache_size  = LFS_CACHE_SIZE,
     .block_size   = LFS_BLOCK_SIZE,
     .block_count  = LFS_BLOCK_COUNT,
+    .block_cycles = LFS_BLOCK_CYCLES,
+    .cache_size   = LFS_CACHE_SIZE,
     .lookahead    = LFS_LOOKAHEAD,
 }};