X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Ffilesys%2Ffilesys.c;h=7a53f5ffd924ca7b1b384fd9b46b3256e14f30e6;hb=fd2a5afa946474ba0839de0e9da238dbaecbd6a5;hp=6a763fecdb60e8e8b323e0d706c20b7ea6549e43;hpb=9d6ad9a479ddae9628dc2d45862f9281986c430b;p=pintos-anon

diff --git a/src/filesys/filesys.c b/src/filesys/filesys.c
index 6a763fe..7a53f5f 100644
--- a/src/filesys/filesys.c
+++ b/src/filesys/filesys.c
@@ -1,145 +1,43 @@
-/* This file is derived from source code for the Nachos
-   instructional operating system.  The Nachos copyright notice
-   is reproduced in full below. */
-
-/* Copyright (c) 1992-1996 The Regents of the University of California.
-   All rights reserved.
-
-   Permission to use, copy, modify, and distribute this software
-   and its documentation for any purpose, without fee, and
-   without written agreement is hereby granted, provided that the
-   above copyright notice and the following two paragraphs appear
-   in all copies of this software.
-
-   IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO
-   ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR
-   CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE
-   AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA
-   HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-   THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY
-   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-   PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
-   BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
-   PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
-   MODIFICATIONS.
-*/
-
 #include "filesys/filesys.h"
-#include <bitmap.h>
 #include <debug.h>
 #include <stdio.h>
 #include <string.h>
 #include "filesys/file.h"
+#include "filesys/free-map.h"
 #include "filesys/inode.h"
 #include "filesys/directory.h"
-#include "devices/disk.h"
-
-/* Filesystem.
-
-   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
-   struct inode, that is stored by itself in a single sector (see
-   inode.h).  The header contains the file's length in bytes and
-   an array that lists the sector numbers for the file's
-   contents.
-
-   Two files are special.  The first special file is the free
-   map, whose inode is always stored in sector 0
-   (FREE_MAP_SECTOR).  The free map stores a bitmap (see
-   lib/bitmap.h) that contains one bit for each sector on the
-   disk.  Each bit that corresponds to a sector within a file is
-   set to true, and the other bits, which are not part of any
-   file, are set to false.
-
-   The second special file is the root directory, whose inode is
-   always stored in sector 1 (ROOT_DIR_SECTOR).  The root
-   directory file stores an array of `struct dir_entry' (see
-   directory.h), each of which, if it is in use, associates a
-   filename with the sector of the file's inode.
-
-   The filesystem implemented here has the following limitations:
-
-     - No synchronization.  Concurrent accesses will interfere
-       with one another, so external synchronization is needed.
-
-     - File size is fixed at creation time.  Because the root
-       directory is represented as a file, the number of files
-       that may be created is also limited.
-
-     - File data is allocated as a single extent, so that
-       external fragmentation can become a serious problem as a
-       file system is used over time.
-
-     - No subdirectories.
-
-     - Filenames limited to 14 characters.
-
-     - A system crash mid-operation may corrupt the disk in a way
-       that cannot be repaired automatically.  No `fsck' tool is
-       provided in any case.
-
-   However one important feature is included:
-
-     - Unix-like semantics for filesys_remove() are implemented.
-       That is, if a file is open when it is removed, its blocks
-       are not deallocated and it may still be accessed by the
-       threads that have it open until the last one closes it. */
 
-/* Sectors of system file inodes. */
-#define FREE_MAP_SECTOR 0       /* Free map file inode sector. */
-#define ROOT_DIR_SECTOR 1       /* Root directory file inode sector. */
-
-/* Root directory. */
-#define NUM_DIR_ENTRIES 10      /* Maximum number of directory entries. */
-
-/* The disk that contains the filesystem. */
-struct disk *filesys_disk;
-
-/* The free map and root directory files.
-   These files are opened by filesys_init() and never closed. */
-struct file *free_map_file, *root_dir_file;
+/* Partition that contains the file system. */
+struct block *fs_device;
 
 static void do_format (void);
 
-/* Initializes the filesystem module.
-   If FORMAT is true, reformats the filesystem. */
+/* Initializes the file system module.
+   If FORMAT is true, reformats the file system. */
 void
 filesys_init (bool format) 
 {
-  inode_init ();
+  fs_device = block_get_role (BLOCK_FILESYS);
+  if (fs_device == NULL)
+    PANIC ("No file system device found, can't initialize file system.");
 
-  filesys_disk = disk_get (0, 1);
-  if (filesys_disk == NULL)
-    PANIC ("hd0:1 (hdb) not present, filesystem initialization failed");
+  inode_init ();
+  free_map_init ();
 
   if (format) 
     do_format ();
-  
-  free_map_file = file_open (FREE_MAP_SECTOR);
-  if (free_map_file == NULL)
-    PANIC ("can't open free map file");
-  root_dir_file = file_open (ROOT_DIR_SECTOR);
-  if (root_dir_file == NULL)
-    PANIC ("can't open root dir file");
+
+  free_map_open ();
 }
 
-/* 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. */
+/* Shuts down the file system module, writing any unwritten data
+   to disk. */
 void
 filesys_done (void) 
 {
+  free_map_close ();
 }
-
+
 /* Creates a file named NAME with the given INITIAL_SIZE.
    Returns true if successful, false otherwise.
    Fails if a file named NAME already exists,
@@ -147,56 +45,20 @@ filesys_done (void)
 bool
 filesys_create (const char *name, off_t initial_size) 
 {
-  struct dir *dir = NULL;
-  struct bitmap *free_map = NULL;
-  struct inode *inode = NULL;
-  disk_sector_t inode_sector;
-  bool success = false;
-
-  /* Read the root directory. */
-  dir = dir_create (NUM_DIR_ENTRIES);
-  if (dir == NULL)
-    goto done;
-  dir_read (dir, root_dir_file);
-  if (dir_lookup (dir, name, NULL)) 
-    goto done;
-
-  /* Allocate a block for the inode. */
-  free_map = bitmap_create (disk_size (filesys_disk));
-  if (free_map == NULL)
-    goto done;
-  bitmap_read (free_map, free_map_file);
-  inode_sector = bitmap_scan_and_flip (free_map, 0, 1, false);
-  if (inode_sector == BITMAP_ERROR)
-    goto done;
-
-  /* Add the file to the directory. */
-  if (!dir_add (dir, name, inode_sector))
-    goto done;
-
-  /* Allocate space for the file. */
-  inode = inode_create (free_map, inode_sector, initial_size);
-  if (inode == NULL)
-    goto done;
-
-  /* Write everything back. */
-  inode_commit (inode);
-  dir_write (dir, root_dir_file);
-  bitmap_write (free_map, free_map_file);
-
-  success = true;
-
-  /* Clean up. */
- done:
-  inode_close (inode);
-  bitmap_destroy (free_map);
-  dir_destroy (dir);
+  block_sector_t inode_sector = 0;
+  struct dir *dir = dir_open_root ();
+  bool success = (dir != NULL
+                  && free_map_allocate (1, &inode_sector)
+                  && inode_create (inode_sector, initial_size)
+                  && dir_add (dir, name, inode_sector));
+  if (!success && inode_sector != 0) 
+    free_map_release (inode_sector, 1);
+  dir_close (dir);
 
   return success;
 }
 
-/* Opens a file named NAME and initializes FILE for usage with
-   the file_*() functions declared in file.h.
+/* Opens the file with the given NAME.
    Returns the new file if successful or a null pointer
    otherwise.
    Fails if no file named NAME exists,
@@ -204,22 +66,14 @@ filesys_create (const char *name, off_t initial_size)
 struct file *
 filesys_open (const char *name)
 {
-  struct dir *dir = NULL;
-  struct file *file = NULL;
-  disk_sector_t inode_sector;
-
-  dir = dir_create (NUM_DIR_ENTRIES);
-  if (dir == NULL)
-    goto done;
-
-  dir_read (dir, root_dir_file);
-  if (dir_lookup (dir, name, &inode_sector))
-    file = file_open (inode_sector);
+  struct dir *dir = dir_open_root ();
+  struct inode *inode = NULL;
 
- done:
-  dir_destroy (dir); 
+  if (dir != NULL)
+    dir_lookup (dir, name, &inode);
+  dir_close (dir);
 
-  return file;
+  return file_open (inode);
 }
 
 /* Deletes the file named NAME.
@@ -229,202 +83,21 @@ filesys_open (const char *name)
 bool
 filesys_remove (const char *name) 
 {
-  struct dir *dir = NULL;
-  struct inode *inode;
-  disk_sector_t inode_sector;
-  bool success = false;
-
-  /* Read the root directory. */
-  dir = dir_create (NUM_DIR_ENTRIES);
-  if (dir == NULL)
-    goto done;
-  dir_read (dir, root_dir_file);
-  if (!dir_lookup (dir, name, &inode_sector))
-    goto done;
-
-  /* Open the inode and delete it. */
-  inode = inode_open (inode_sector);
-  if (inode == NULL)
-    goto done;
-  inode_remove (inode);
-  inode_close (inode);
-
-  /* Remove file from root directory and write directory back to
-     disk. */
-  dir_remove (dir, name);
-  dir_write (dir, root_dir_file);
-
-  success = true;
-
-  /* Clean up. */
- done:
-  dir_destroy (dir);
+  struct dir *dir = dir_open_root ();
+  bool success = dir != NULL && dir_remove (dir, name);
+  dir_close (dir); 
 
   return success;
 }
-
-/* Prints a list of files in the filesystem to the system
-   console.
-   Returns true if successful, false on failure,
-   which occurs only if an internal memory allocation fails. */
-bool
-filesys_list (void) 
-{
-  struct dir *dir = dir_create (NUM_DIR_ENTRIES);
-  if (dir == NULL)
-    return false;
-  dir_read (dir, root_dir_file);
-  dir_list (dir);
-  dir_destroy (dir);
-
-  return true;
-}
-
-/* Dumps the filesystem state to the system console,
-   including the free map, the list of files, and file contents.
-   Returns true if successful, false on failure,
-   which occurs only if an internal memory allocation fails. */
-bool
-filesys_dump (void) 
-{
-  struct bitmap *free_map;
-  struct dir *dir;  
-
-  printf ("Free map:\n");
-  free_map = bitmap_create (disk_size (filesys_disk));
-  if (free_map == NULL)
-    return false;
-  bitmap_read (free_map, free_map_file);
-  bitmap_dump (free_map);
-  bitmap_destroy (free_map);
-  printf ("\n");
-  
-  dir = dir_create (NUM_DIR_ENTRIES);
-  if (dir == NULL)
-    return false;
-  dir_read (dir, root_dir_file);
-  dir_dump (dir);
-  dir_destroy (dir);
-
-  return true;
-}
-
-static void must_succeed_function (int, bool) NO_INLINE;
-#define MUST_SUCCEED(EXPR) must_succeed_function (__LINE__, EXPR)
-
-/* Performs basic sanity checks on the filesystem.
-   The filesystem should not contain a file named `foo' when
-   called. */
-void
-filesys_self_test (void)
-{
-  static const char s[] = "This is a test string.";
-  static const char zeros[sizeof s] = {0};
-  struct file *file;
-  char s2[sizeof s];
-  int i;
-
-  filesys_remove ("foo");
-  for (i = 0; i < 2; i++) 
-    {
-      /* Create file and check that it contains zeros
-         throughout the created length. */
-      MUST_SUCCEED (filesys_create ("foo", sizeof s));
-      MUST_SUCCEED ((file = filesys_open ("foo")) != NULL);
-      MUST_SUCCEED (file_read (file, s2, sizeof s2) == sizeof s2);
-      MUST_SUCCEED (memcmp (s2, zeros, sizeof s) == 0);
-      MUST_SUCCEED (file_tell (file) == sizeof s);
-      MUST_SUCCEED (file_length (file) == sizeof s);
-      file_close (file);
-
-      /* Reopen file and write to it. */
-      MUST_SUCCEED ((file = filesys_open ("foo")) != NULL);
-      MUST_SUCCEED (file_write (file, s, sizeof s) == sizeof s);
-      MUST_SUCCEED (file_tell (file) == sizeof s);
-      MUST_SUCCEED (file_length (file) == sizeof s);
-      file_close (file);
-
-      /* Reopen file and verify that it reads back correctly.
-         Delete file while open to check proper semantics. */
-      MUST_SUCCEED ((file = filesys_open ("foo")) != NULL);
-      MUST_SUCCEED (filesys_remove ("foo"));
-      MUST_SUCCEED (file_read (file, s2, sizeof s) == sizeof s);
-      MUST_SUCCEED (memcmp (s, s2, sizeof s) == 0);
-      MUST_SUCCEED (file_tell (file) == sizeof s);
-      MUST_SUCCEED (file_length (file) == sizeof s);
-      file_close (file);
-
-      /* Make sure file is deleted. */
-      MUST_SUCCEED ((file = filesys_open ("foo")) == NULL);
-    }
-  
-  printf ("filesys: self test ok\n");
-}
 
-/* Formats the filesystem. */
+/* Formats the file system. */
 static void
 do_format (void)
 {
-  struct bitmap *free_map;
-  struct inode *map_inode, *dir_inode;
-  struct dir *dir;
-
-  printf ("Formatting filesystem...");
-
-  /* Create the initial bitmap and reserve sectors for the
-     free map and root directory inodes. */
-  free_map = bitmap_create (disk_size (filesys_disk));
-  if (free_map == NULL)
-    PANIC ("bitmap creation failed--disk is too large");
-  bitmap_mark (free_map, FREE_MAP_SECTOR);
-  bitmap_mark (free_map, ROOT_DIR_SECTOR);
-
-  /* Allocate data sector(s) for the free map file
-     and write its inode to disk. */
-  map_inode = inode_create (free_map, FREE_MAP_SECTOR,
-                            bitmap_file_size (free_map));
-  if (map_inode == NULL)
-    PANIC ("free map creation failed--disk is too large");
-  inode_commit (map_inode);
-  inode_close (map_inode);
-
-  /* Allocate data sector(s) for the root directory file
-     and write its inodes to disk. */
-  dir_inode = inode_create (free_map, ROOT_DIR_SECTOR,
-                            dir_size (NUM_DIR_ENTRIES));
-  if (dir_inode == NULL)
+  printf ("Formatting file system...");
+  free_map_create ();
+  if (!dir_create (ROOT_DIR_SECTOR, 16))
     PANIC ("root directory creation failed");
-  inode_commit (dir_inode);
-  inode_close (dir_inode);
-
-  /* Write out the free map now that we have space reserved
-     for it. */
-  free_map_file = file_open (FREE_MAP_SECTOR);
-  if (free_map_file == NULL)
-    PANIC ("can't open free map file");
-  bitmap_write (free_map, free_map_file);
-  bitmap_destroy (free_map);
-  file_close (free_map_file);
-
-  /* Write out the root directory in the same way. */
-  root_dir_file = file_open (ROOT_DIR_SECTOR);
-  if (root_dir_file == NULL)
-    PANIC ("can't open root directory");
-  dir = dir_create (NUM_DIR_ENTRIES);
-  if (dir == NULL)
-    PANIC ("can't initialize root directory");
-  dir_write (dir, root_dir_file);
-  dir_destroy (dir);
-  file_close (root_dir_file);
-
+  free_map_close ();
   printf ("done.\n");
 }
-
-/* If SUCCESS is false, panics with an error complaining about
-   LINE_NO. */
-static void 
-must_succeed_function (int line_no, bool success) 
-{
-  if (!success)
-    PANIC ("filesys_self_test: operation failed on line %d", line_no);
-}