Added limited support for directories

This comes with a lot of scafolding put into place around the core
of the filesystem.

Added operations:
- append an entry to a directory
- find an entry in a directory
- iterate over entries in a directory

Some to do:
- Chaining multiple directory blocks
- Recursion on directory operations

lfs.h

@@ -13,8 +13,17 @@
 
 // Data structures
 enum lfs_error {
-    LFS_ERROR_OK      = 0,
-    LFS_ERROR_CORRUPT = -3,
+    LFS_ERROR_OK       = 0,
+    LFS_ERROR_CORRUPT  = -3,
+    LFS_ERROR_NO_ENTRY = -4,
+    LFS_ERROR_EXISTS   = -5,
+    LFS_ERROR_NOT_DIR  = -6,
+    LFS_ERROR_INVALID  = -7,
+};
+
+enum lfs_type {
+    LFS_TYPE_REG = 1,
+    LFS_TYPE_DIR = 2,
 };
 
 typedef struct lfs_free {
@@ -28,11 +37,12 @@ typedef struct lfs_free {
 
 typedef struct lfs_dir {
     lfs_ino_t pair[2];
+    lfs_off_t i;
+
     lfs_disk_struct lfs_disk_dir {
         lfs_word_t rev;
         lfs_size_t size;
         lfs_ino_t tail[2];
-        lfs_ino_t parent[2];
 
         struct lfs_disk_free free;
     } d;
@@ -49,20 +59,9 @@ typedef struct lfs_entry {
             lfs_disk_struct {
                 lfs_ino_t head;
                 lfs_size_t size;
-                char name[LFS_NAME_MAX];
             } file;
-            lfs_disk_struct {
-                lfs_ino_t dir[2];
-                char name[LFS_NAME_MAX];
-            } dir;
-            lfs_disk_struct {
-                char magic[4];
-                uint32_t read_size;
-                uint32_t write_size;
-                uint32_t erase_size;
-                uint32_t erase_count;
-            } superblock;
-        } value;
+            lfs_ino_t dir[2];
+        } u;
     } d;
 } lfs_entry_t;
 
@@ -83,6 +82,7 @@ typedef struct lfs {
     lfs_bd_t *bd;
     const struct lfs_bd_ops *ops;
 
+    lfs_ino_t cwd[2];
     lfs_free_t free;
     struct lfs_bd_info info;
 } lfs_t;
@@ -92,4 +92,7 @@ lfs_error_t lfs_create(lfs_t *lfs, lfs_bd_t *bd, const struct lfs_bd_ops *bd_ops
 lfs_error_t lfs_format(lfs_t *lfs);
 lfs_error_t lfs_mount(lfs_t *lfs);
 
+lfs_error_t lfs_mkdir(lfs_t *lfs, const char *path);
+
+
 #endif