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;
         }
@@ -975,10 +981,9 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
 
 static int lfs_dir_fetch(lfs_t *lfs,
         lfs_mdir_t *dir, const lfs_block_t pair[2]) {
-    // note, mask=-1, tag=-1 can never match a tag since this
+    // note, mask=-1, tag=0 can never match a tag since this
     // pattern has the invalid bit set
-    return (int)lfs_dir_fetchmatch(lfs, dir, pair,
-            (lfs_tag_t)-1, (lfs_tag_t)-1, NULL, NULL, NULL);
+    return (int)lfs_dir_fetchmatch(lfs, dir, pair, -1, 0, NULL, NULL, NULL);
 }
 
 static int lfs_dir_getgstate(lfs_t *lfs, const lfs_mdir_t *dir,
@@ -1644,6 +1649,7 @@ relocate:
         if (err && (err != LFS_ERR_NOSPC && !exhausted)) {
             return err;
         }
+
         continue;
     }