Added debug statement for block allocation scan

This may be useful for determining when allocation passes occur,
especially as performance and latency becomes a growing concern.

lfs.c

@@ -466,9 +466,15 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
             }
         }
 
+        // no free blocks in lookahead buffer, need to scan tree
+        LFS_DEBUG("Scanning for free blocks %"PRIx32"-%"PRIx32,
+                lfs->free.i + lfs->free.off,
+                (lfs->free.i + lfs->free.off + 8*lfs->cfg->lookahead_size)
+                    % lfs->cfg->block_count);
+
         // check if we have looked at all blocks since last ack
         if (lfs->free.ack == 0) {
-            LFS_ERROR("No more free space %"PRIu32,
+            LFS_ERROR("No more free space %"PRIx32,
                     lfs->free.i + lfs->free.off);
             return LFS_ERR_NOSPC;
         }
@@ -1503,13 +1509,9 @@ static int lfs_dir_compact(lfs_t *lfs,
                 }
             }
 #ifdef LFS_MIGRATE
-        } else if (lfs->lfs1) {
+        } else if (lfs_pair_cmp(dir->pair, lfs->root) == 0 && lfs->lfs1) {
-            // do not proactively relocate blocks during migrations, this
+            // we can't relocate our root during migrations, as this would
-            // can cause a number of failure states such: clobbering the
+            // cause the superblock to get updated, which would clobber v1
-            // v1 superblock if we relocate root, and invalidating directory
-            // pointers if we relocate the head of a directory. On top of
-            // this, relocations increase the overall complexity of
-            // lfs_migration, which is already a delicate operation.
 #endif
         } else {
             // we're writing too much, time to relocate
@@ -2068,14 +2070,10 @@ int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
     dir->pos = lfs_min(2, off);
     off -= dir->pos;
 
-    // skip superblock entry
+    while (off != 0) {
-    dir->id = (off > 0 && lfs_pair_cmp(dir->head, lfs->root) == 0);
+        dir->id = lfs_min(dir->m.count, off);
-
+        dir->pos += dir->id;
-    while (off > 0) {
+        off -= dir->id;
-        int diff = lfs_min(dir->m.count - dir->id, off);
-        dir->id += diff;
-        dir->pos += diff;
-        off -= diff;
 
         if (dir->id == dir->m.count) {
             if (!dir->m.split) {
@@ -2088,8 +2086,6 @@ int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
                 LFS_TRACE("lfs_dir_seek -> %d", err);
                 return err;
             }
-
-            dir->id = 0;
         }
     }
 

tests/test_seek.sh

@@ -428,78 +428,4 @@ scripts/test.py << TEST
 TEST
 done
 
-echo "--- Root seek test ---"
-./scripts/test.py << TEST
-    lfs_mount(&lfs, &cfg) => 0;
-    for (int i = 3; i < $MEDIUMSIZE; i++) {
-        sprintf(path, "hi%03d", i);
-        lfs_mkdir(&lfs, path) => 0;
-    }
-
-    lfs_dir_open(&lfs, &dir, "/") => 0;
-    for (int i = 0; i < $MEDIUMSIZE; i++) {
-        if (i == 0) {
-            sprintf(path, ".");
-        } else if (i == 1) {
-            sprintf(path, "..");
-        } else if (i == 2) {
-            sprintf(path, "hello");
-        } else {
-            sprintf(path, "hi%03d", i);
-        }
-        lfs_dir_read(&lfs, &dir, &info) => 1;
-        strcmp(path, info.name) => 0;
-    }
-    lfs_dir_read(&lfs, &dir, &info) => 0;
-    lfs_dir_close(&lfs, &dir) => 0;
-
-    for (int j = 0; j < $MEDIUMSIZE; j++) {
-        lfs_soff_t off = -1;
-
-        lfs_dir_open(&lfs, &dir, "/") => 0;
-        for (int i = 0; i < $MEDIUMSIZE; i++) {
-            if (i == 0) {
-                sprintf(path, ".");
-            } else if (i == 1) {
-                sprintf(path, "..");
-            } else if (i == 2) {
-                sprintf(path, "hello");
-            } else {
-                sprintf(path, "hi%03d", i);
-            }
-
-            if (i == j) {
-                off = lfs_dir_tell(&lfs, &dir);
-                off >= 0 => true;
-            }
-
-            lfs_dir_read(&lfs, &dir, &info) => 1;
-            strcmp(path, info.name) => 0;
-        }
-        lfs_dir_read(&lfs, &dir, &info) => 0;
-        lfs_dir_close(&lfs, &dir) => 0;
-
-        lfs_dir_open(&lfs, &dir, "/") => 0;
-        lfs_dir_seek(&lfs, &dir, off) => 0;
-        for (int i = j; i < $MEDIUMSIZE; i++) {
-            if (i == 0) {
-                sprintf(path, ".");
-            } else if (i == 1) {
-                sprintf(path, "..");
-            } else if (i == 2) {
-                sprintf(path, "hello");
-            } else {
-                sprintf(path, "hi%03d", i);
-            }
-
-            lfs_dir_read(&lfs, &dir, &info) => 1;
-            strcmp(path, info.name) => 0;
-        }
-        lfs_dir_read(&lfs, &dir, &info) => 0;
-        lfs_dir_close(&lfs, &dir) => 0;
-    }
-
-    lfs_unmount(&lfs) => 0;
-TEST
-
 scripts/results.py