Fixed missing erase during file relocation

This was an easy fix, but highlighted the fact that the current testing
framework doesn't detect when a block is written to without an
associated erase.

Added a quick solution that creates an empty file during an erase.

1 files changed, 17 insertions, 5 deletions

diff --git a/emubd/lfs_emubd.c b/emubd/lfs_emubd.c
index 2c3b348..9e34f6e 100644
--- a/emubd/lfs_emubd.c
+++ b/emubd/lfs_emubd.c
@@ -127,13 +127,13 @@ int lfs_emubd_prog(const struct lfs_config *cfg, lfs_block_t block,
     snprintf(emu->child, LFS_NAME_MAX, "%x", block);
 
     FILE *f = fopen(emu->path, "r+b");
-    if (!f && errno == ENOENT) {
-        f = fopen(emu->path, "w+b");
-        if (!f) {
-            return -errno;
-        }
+    if (!f && errno != ENOENT) {
+        return -errno;
     }
 
+    // Check that file was erased
+    assert(f);
+
     int err = fseek(f, off, SEEK_SET);
     if (err) {
         return -errno;
@@ -185,6 +185,18 @@ int lfs_emubd_erase(const struct lfs_config *cfg, lfs_block_t block) {
         }
     }
 
+    if (err || S_ISREG(st.st_mode)) {
+        FILE *f = fopen(emu->path, "w");
+        if (!f) {
+            return -errno;
+        }
+
+        err = fclose(f);
+        if (err) {
+            return -errno;
+        }
+    }
+
     emu->stats.erase_count += 1;
     return 0;
 }