Comments.

[pintos-anon] / src / filesys / filesys.c

diff --git a/src/filesys/filesys.c b/src/filesys/filesys.c
index 8bd39e80ff52ef82eaf1056117448373daf8b7fa..7b164380809f5675f7080584801654a416843c2f 100644 (file)
--- a/src/filesys/filesys.c
+++ b/src/filesys/filesys.c
@@ -38,10 +38,11 @@
 
 /* Filesystem.
 
-   For the purposes of the "user processes" assignment (project
-   2), please treat all the code in the filesys directory as a
-   black box.  No changes should be needed.  For that project, a
-   single lock external to the filesystem code suffices.
+   For the purposes of the "user processes" and "virtual memory"
+   assignments (projects 2 and 3), please treat all the code in
+   the filesys directory as a black box.  No changes should be
+   needed.  For those projects, a single lock external to the
+   filesystem code suffices.
 
    The filesystem consists of a set of files.  Each file has a
    header called an `index node' or `inode', represented by
@@ -131,6 +132,15 @@ filesys_init (bool format)
     PANIC ("can't open root dir file");
 }
 
+/* Shuts down the filesystem module, writing any unwritten data
+   to disk.
+   Currently there's nothing to do.  You'll need to add code here
+   when you implement write-behind caching. */
+void
+filesys_done (void) 
+{
+}
+
 /* Creates a file named NAME with the given INITIAL_SIZE.
    Returns true if successful, false otherwise.
    Fails if a file named NAME already exists,
@@ -157,7 +167,7 @@ filesys_create (const char *name, off_t initial_size)
   if (free_map == NULL)
     goto done;
   bitmap_read (free_map, free_map_file);
-  inode_sector = bitmap_find_and_set (free_map);
+  inode_sector = bitmap_scan_and_flip (free_map, 0, 1, false);
   if (inode_sector == BITMAP_ERROR)
     goto done;
 
@@ -188,7 +198,8 @@ filesys_create (const char *name, off_t initial_size)
 
 /* Opens a file named NAME and initializes FILE for usage with
    the file_*() functions declared in file.h.
-   Returns true if successful, false on failure.
+   Returns the new file if successful or a null pointer
+   otherwise.
    Fails if no file named NAME exists,
    or if an internal memory allocation fails. */
 struct file *
@@ -232,7 +243,7 @@ filesys_remove (const char *name)
   if (!dir_lookup (dir, name, &inode_sector))
     goto done;
 
-  /* Open the inode and delete it it. */
+  /* Open the inode and delete it. */
   inode = inode_open (inode_sector);
   if (inode == NULL)
     goto done;