+/* 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.h"
-#include "disk.h"
+#include "file.h"
+#include "filehdr.h"
#include "directory.h"
-
-static struct disk *disk;
-
+#include "devices/disk.h"
+#include "lib/bitmap.h"
+#include "lib/debug.h"
+#include "lib/lib.h"
+
+/* Filesystem.
+
+ The filesystem consists of a set of files. Each file has a
+ header, represented by struct filehdr, that is stored by
+ itself in a single sector (see filehdr.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 header 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 header 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 header.
+
+ The filesystem implemented here has the following limitations:
+
+ - No synchronization. Concurrent accesses will interfere
+ with one another.
+
+ - 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.
+
+ - No indirect blocks. This limits maximum file size to the
+ number of sector pointers that fit in a single sector
+ times the size of a sector, or 126 * 512 == 63 kB given
+ 32-bit sizes and 512-byte sectors.
+
+ - No nested 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.
+
+ Note: 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. */
+
+/* File header sectors for system files. */
+#define FREE_MAP_SECTOR 0 /* Free map file header sector. */
+#define ROOT_DIR_SECTOR 1 /* Root directory file header sector. */
+
+/* Root directory. */
+#define NUM_DIR_ENTRIES 10 /* Maximum number of directory entries. */
+#define ROOT_DIR_FILE_SIZE /* Root directory file size in bytes. */ \
+ (sizeof (struct dir_entry) * NUM_DIR_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. */
static struct file free_map_file, root_dir_file;
-#define FREE_MAP_SECTOR 0
-#define ROOT_DIR_SECTOR 1
-
-#define NUM_DIR_ENTRIES 10
-#define ROOT_DIR_FILE_SIZE (sizeof (struct dir_entry) * NUM_DIR_ENTRIES)
-
-static void
-do_format (void)
-{
- struct bitmap free_map;
- struct filehdr map_hdr, dir_hdr;
- struct dir dir;
-
- /* Create the initial bitmap and reserve sectors for the
- free map and root directory file headers. */
- bitmap_init (&free_map, disk_size (disk));
- 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 file header to disk. */
- if (!filehdr_allocate (&map_hdr, bitmap_storage_size (&free_map)))
- panic ("free map creation failed");
- filehdr_write (&map_hdr, FREE_MAP_SECTOR);
- filehdr_destroy (&map_hdr);
-
- /* Allocate data sector(s) for the root directory file
- and write its file header to disk. */
- if (!filehdr_allocate (&dir_hdr, ROOT_DIR_FILE_SIZE))
- panic ("root directory creation failed");
- filehdr_write (&dir_hdr, FREE_MAP_SECTOR);
- filehdr_destroy (&dir_hdr);
-
- /* Write out the free map now that we have space reserved
- for it. */
- file_open (&free_map_file, FREE_MAP_SECTOR);
- bitmapio_write (&free_map, free_map_file);
- bitmap_destroy (&free_map);
- file_close (&free_map_file);
-
- /* Write out the root directory in the same way. */
- file_open (&root_dir_file, ROOT_DIR_SECTOR);
- if (!dir_init (&dir, NUM_DIR_ENTRIES))
- panic ("can't initialize root directory");
- dir_write (root_dir_file);
- dir_destroy (&dir);
- file_close (&free_map_file);
-}
+static void do_format (void);
+/* Initializes the filesystem module.
+ If FORMAT is true, reformats the filesystem. */
void
filesys_init (bool format)
{
- disk = disk_get (1);
- if (disk == NULL)
- panic ("ide1:1 not present, filesystem initialization failed");
+ filesys_disk = disk_get (0, 1);
+ if (filesys_disk == NULL)
+ PANIC ("hd0:1 (hdb) not present, filesystem initialization failed");
if (format)
do_format ();
- file_open (&free_map_file, FREE_MAP_SECTOR);
- file_open (&root_dir_file, ROOT_DIR_SECTOR);
+ if (!file_open (&free_map_file, FREE_MAP_SECTOR))
+ PANIC ("can't open free map file");
+ if (!file_open (&root_dir_file, ROOT_DIR_SECTOR))
+ PANIC ("can't open root dir file");
}
+/* Creates a file named NAME with the given INITIAL_SIZE.
+ Returns true if successful, false otherwise.
+ Fails if a file named NAME already exists,
+ or if internal memory allocation fails. */
bool
filesys_create (const char *name, off_t initial_size)
{
struct dir dir;
struct bitmap free_map;
- disk_sector_no hdr_sector;
- struct filehdr filehdr;
+ disk_sector_t hdr_sector;
+ struct filehdr *filehdr;
bool success = false;
/* Read the root directory. */
- dir_init (&dir, NUM_DIR_ENTRIES);
+ if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ return false;
dir_read (&dir, &root_dir_file);
if (dir_lookup (&dir, name, NULL))
goto exit1;
/* Allocate a block for the file header. */
- bitmap_init (&free_map, disk_size (disk));
- bitmapio_read (&free_map, &free_map_file);
+ if (!bitmap_init (&free_map, disk_size (filesys_disk)))
+ goto exit1;
+ bitmap_read (&free_map, &free_map_file);
hdr_sector = bitmap_find_and_set (&free_map);
if (hdr_sector == BITMAP_ERROR)
goto exit2;
goto exit2;
/* Allocate space for the file. */
- if (!filehdr_allocate (&filehdr, initial_size))
+ filehdr = filehdr_allocate (&free_map, initial_size);
+ if (filehdr == NULL)
goto exit2;
/* Write everything back. */
- filehdr_write (&filehdr, hdr_sector);
+ filehdr_write (filehdr, hdr_sector);
dir_write (&dir, &root_dir_file);
- bitmapio_write (&free_map, &free_map_file);
+ bitmap_write (&free_map, &free_map_file);
success = true;
/* Clean up. */
- filehdr_destroy (&filehdr);
+ filehdr_destroy (filehdr);
exit2:
bitmap_destroy (&free_map);
exit1:
return success;
}
+/* 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.
+ Fails if no file named NAME exists,
+ or if an internal memory allocation fails. */
+bool
+filesys_open (const char *name, struct file *file)
+{
+ struct dir dir;
+ disk_sector_t hdr_sector;
+ bool success = false;
+
+ if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ return false;
+ dir_read (&dir, &root_dir_file);
+ if (dir_lookup (&dir, name, &hdr_sector))
+ success = file_open (file, hdr_sector);
+
+ dir_destroy (&dir);
+ return success;
+}
+
+/* Deletes the file named NAME.
+ Returns true if successful, false on failure.
+ Fails if no file named NAME exists,
+ or if an internal memory allocation fails. */
bool
filesys_remove (const char *name)
{
struct dir dir;
- disk_sector_no hdr_sector;
- struct filehdr filehdr;
+ disk_sector_t hdr_sector;
+ struct filehdr *filehdr;
struct bitmap free_map;
bool success = false;
/* Read the root directory. */
- dir_init (&dir, NUM_DIR_ENTRIES);
+ if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ return false;
dir_read (&dir, &root_dir_file);
if (!dir_lookup (&dir, name, &hdr_sector))
- goto exit;
+ goto exit1;
/* Read the file header. */
- filehdr_read (&filehdr, hdr_sector);
+ filehdr = filehdr_read (hdr_sector);
+ if (filehdr == NULL)
+ goto exit1;
/* Allocate a block for the file header. */
- bitmap_init (&free_map, disk_size (disk));
- bitmapio_read (&free_map, &free_map_file);
+ if (!bitmap_init (&free_map, disk_size (filesys_disk)))
+ goto exit2;
+ bitmap_read (&free_map, &free_map_file);
/* Deallocate. */
- filehdr_deallocate (&filehdr, &free_map);
+ filehdr_deallocate (filehdr, &free_map);
bitmap_reset (&free_map, hdr_sector);
dir_remove (&dir, name);
/* Write everything back. */
- bitmapio_write (&free_map, &free_map_file);
+ bitmap_write (&free_map, &free_map_file);
dir_write (&dir, &root_dir_file);
success = true;
/* Clean up. */
- filehdr_destroy (&filehdr);
bitmap_destroy (&free_map);
- exit:
+ exit2:
+ filehdr_destroy (filehdr);
+ exit1:
dir_destroy (&dir);
return success;
}
-#undef NDEBUG
-#include "debug.h"
-#include "file.h"
+/* 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;
+
+ if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ 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;
+
+ printk ("Free map:\n");
+ if (!bitmap_init (&free_map, disk_size (filesys_disk)))
+ return false;
+ bitmap_read (&free_map, &free_map_file);
+ bitmap_dump (&free_map);
+ bitmap_destroy (&free_map);
+ printk ("\n");
+
+ if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ 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.";
- struct file *file;
+ struct file file;
char s2[sizeof s];
- ASSERT (filesys_create ("foo"));
- ASSERT ((file = filesys_open ("foo")) != NULL);
- ASSERT (file_write (file, s, sizeof s) == sizeof s);
- ASSERT (file_tell (file) == sizeof s);
- ASSERT (file_length (file) == sizeof s);
- file_close (file);
-
- ASSERT ((file = filesys_open ("foo")) != NULL);
- ASSERT (file_read (file, s2, sizeof s2) == sizeof s2);
- ASSERT (memcmp (s, s2, sizeof s) == 0);
- ASSERT (file_tell (file) == sizeof s2);
- ASSERT (file_length (file) == sizeof s2);
- file_close (file);
-
- ASSERT (filesys_remove ("foo"));
+ MUST_SUCCEED (filesys_create ("foo", sizeof s));
+ MUST_SUCCEED (filesys_open ("foo", &file));
+ 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);
+
+ MUST_SUCCEED (filesys_open ("foo", &file));
+ MUST_SUCCEED (file_read (&file, s2, sizeof s2) == sizeof s2);
+ MUST_SUCCEED (memcmp (s, s2, sizeof s) == 0);
+ MUST_SUCCEED (file_tell (&file) == sizeof s2);
+ MUST_SUCCEED (file_length (&file) == sizeof s2);
+ file_close (&file);
+
+ MUST_SUCCEED (filesys_remove ("foo"));
+
+ printk ("filesys: self test ok\n");
+}
+\f
+/* Formats the filesystem. */
+static void
+do_format (void)
+{
+ struct bitmap free_map;
+ struct filehdr *map_hdr, *dir_hdr;
+ struct dir dir;
+
+ printk ("Formatting filesystem...");
+
+ /* Create the initial bitmap and reserve sectors for the
+ free map and root directory file headers. */
+ if (!bitmap_init (&free_map, disk_size (filesys_disk)))
+ 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 file header to disk. */
+ map_hdr = filehdr_allocate (&free_map, bitmap_file_size (&free_map));
+ if (map_hdr == NULL)
+ PANIC ("free map creation failed--disk is too large");
+ filehdr_write (map_hdr, FREE_MAP_SECTOR);
+ filehdr_destroy (map_hdr);
+
+ /* Allocate data sector(s) for the root directory file
+ and write its file header to disk. */
+ dir_hdr = filehdr_allocate (&free_map, ROOT_DIR_FILE_SIZE);
+ if (dir_hdr == NULL)
+ PANIC ("root directory creation failed");
+ filehdr_write (dir_hdr, ROOT_DIR_SECTOR);
+ filehdr_destroy (dir_hdr);
+
+ /* Write out the free map now that we have space reserved
+ for it. */
+ if (!file_open (&free_map_file, FREE_MAP_SECTOR))
+ 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. */
+ if (!file_open (&root_dir_file, ROOT_DIR_SECTOR))
+ PANIC ("can't open root directory");
+ if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ PANIC ("can't initialize root directory");
+ dir_write (&dir, &root_dir_file);
+ dir_destroy (&dir);
+ file_close (&free_map_file);
+
+ printk ("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);
}
projects / pintos-anon / blobdiff