#include <stdio.h>
#include <string.h>
#include "filesys/file.h"
-#include "filesys/filehdr.h"
+#include "filesys/inode.h"
#include "filesys/directory.h"
#include "devices/disk.h"
/* 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.
+
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.
+ 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 header is always stored in sector 0
+ 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 header is
+ 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 header.
+ 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.
+ 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.
- No indirect blocks. This limits maximum file size to the
- number of sector pointers that fit in a single sector
+ number of sector pointers that fit in a single inode
times the size of a sector, or 126 * 512 == 63 kB given
32-bit sizes and 512-byte sectors.
- - No nested subdirectories.
+ - No subdirectories.
- Filenames limited to 14 characters.
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. */
+ 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. */
-/* 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. */
+/* 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. */
-#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;
+struct file *free_map_file, *root_dir_file;
static void do_format (void);
void
filesys_init (bool format)
{
+ inode_init ();
+
filesys_disk = disk_get (0, 1);
if (filesys_disk == NULL)
PANIC ("hd0:1 (hdb) not present, filesystem initialization failed");
if (format)
do_format ();
- if (!file_open (&free_map_file, FREE_MAP_SECTOR))
+ free_map_file = file_open (FREE_MAP_SECTOR);
+ if (free_map_file == NULL)
PANIC ("can't open free map file");
- if (!file_open (&root_dir_file, ROOT_DIR_SECTOR))
+ root_dir_file = file_open (ROOT_DIR_SECTOR);
+ if (root_dir_file == NULL)
PANIC ("can't open root dir file");
}
bool
filesys_create (const char *name, off_t initial_size)
{
- struct dir dir;
- struct bitmap free_map;
- disk_sector_t hdr_sector;
- struct filehdr *filehdr;
+ 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. */
- 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. */
- 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;
+ 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_find_and_set (free_map);
+ if (inode_sector == BITMAP_ERROR)
+ goto done;
/* Add the file to the directory. */
- if (!dir_add (&dir, name, hdr_sector))
- goto exit2;
+ if (!dir_add (dir, name, inode_sector))
+ goto done;
/* Allocate space for the file. */
- filehdr = filehdr_allocate (&free_map, initial_size);
- if (filehdr == NULL)
- goto exit2;
+ inode = inode_create (free_map, inode_sector, initial_size);
+ if (inode == NULL)
+ goto done;
/* Write everything back. */
- filehdr_write (filehdr, hdr_sector);
- dir_write (&dir, &root_dir_file);
- bitmap_write (&free_map, &free_map_file);
+ inode_commit (inode);
+ dir_write (dir, root_dir_file);
+ bitmap_write (free_map, free_map_file);
success = true;
/* Clean up. */
- filehdr_destroy (filehdr);
- exit2:
- bitmap_destroy (&free_map);
- exit1:
- dir_destroy (&dir);
+ done:
+ inode_close (inode);
+ bitmap_destroy (free_map);
+ dir_destroy (dir);
return success;
}
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 file *
+filesys_open (const char *name)
{
- struct dir dir;
- disk_sector_t hdr_sector;
- bool success = false;
+ struct dir *dir = NULL;
+ struct file *file = NULL;
+ disk_sector_t inode_sector;
- 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;
+ 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);
+
+ done:
+ dir_destroy (dir);
+
+ return file;
}
/* Deletes the file named NAME.
bool
filesys_remove (const char *name)
{
- struct dir dir;
- disk_sector_t hdr_sector;
- struct filehdr *filehdr;
- struct bitmap free_map;
+ struct dir *dir = NULL;
+ struct inode *inode;
+ disk_sector_t inode_sector;
bool success = false;
/* Read the root directory. */
- if (!dir_init (&dir, NUM_DIR_ENTRIES))
- return false;
- dir_read (&dir, &root_dir_file);
- if (!dir_lookup (&dir, name, &hdr_sector))
- goto exit1;
-
- /* Read the file header. */
- filehdr = filehdr_read (hdr_sector);
- if (filehdr == NULL)
- goto exit1;
-
- /* Allocate a block for the file header. */
- if (!bitmap_init (&free_map, disk_size (filesys_disk)))
- goto exit2;
- bitmap_read (&free_map, &free_map_file);
-
- /* Deallocate. */
- filehdr_deallocate (filehdr, &free_map);
- bitmap_reset (&free_map, hdr_sector);
- dir_remove (&dir, name);
-
- /* Write everything back. */
- bitmap_write (&free_map, &free_map_file);
- dir_write (&dir, &root_dir_file);
+ 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 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. */
- bitmap_destroy (&free_map);
- exit2:
- filehdr_destroy (filehdr);
- exit1:
- dir_destroy (&dir);
+ done:
+ dir_destroy (dir);
return success;
}
bool
filesys_list (void)
{
- struct dir dir;
-
- if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ 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);
+ dir_read (dir, root_dir_file);
+ dir_list (dir);
+ dir_destroy (dir);
return true;
}
bool
filesys_dump (void)
{
- struct bitmap free_map;
- struct dir dir;
+ struct bitmap *free_map;
+ struct dir *dir;
printf ("Free map:\n");
- if (!bitmap_init (&free_map, disk_size (filesys_disk)))
+ 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);
+ bitmap_read (free_map, free_map_file);
+ bitmap_dump (free_map);
+ bitmap_destroy (free_map);
printf ("\n");
- if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ dir = dir_create (NUM_DIR_ENTRIES);
+ if (dir == NULL)
return false;
- dir_read (&dir, &root_dir_file);
- dir_dump (&dir);
- dir_destroy (&dir);
+ dir_read (dir, root_dir_file);
+ dir_dump (dir);
+ dir_destroy (dir);
return true;
}
filesys_self_test (void)
{
static const char s[] = "This is a test string.";
- struct file file;
+ static const char zeros[sizeof s] = {0};
+ struct file *file;
char s2[sizeof s];
-
- 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"));
-
+ 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");
}
\f
static void
do_format (void)
{
- struct bitmap free_map;
- struct filehdr *map_hdr, *dir_hdr;
- struct dir dir;
+ 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 file headers. */
- if (!bitmap_init (&free_map, disk_size (filesys_disk)))
+ 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);
+ 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)
+ 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");
- filehdr_write (map_hdr, FREE_MAP_SECTOR);
- filehdr_destroy (map_hdr);
+ inode_commit (map_inode);
+ inode_close (map_inode);
/* 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)
+ and write its inodes to disk. */
+ dir_inode = inode_create (free_map, ROOT_DIR_SECTOR,
+ dir_size (NUM_DIR_ENTRIES));
+ if (dir_inode == NULL)
PANIC ("root directory creation failed");
- filehdr_write (dir_hdr, ROOT_DIR_SECTOR);
- filehdr_destroy (dir_hdr);
+ inode_commit (dir_inode);
+ inode_close (dir_inode);
/* Write out the free map now that we have space reserved
for it. */
- if (!file_open (&free_map_file, FREE_MAP_SECTOR))
+ 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);
+ 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))
+ root_dir_file = file_open (ROOT_DIR_SECTOR);
+ if (root_dir_file == NULL)
PANIC ("can't open root directory");
- if (!dir_init (&dir, NUM_DIR_ENTRIES))
+ 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 (&free_map_file);
+ dir_write (dir, root_dir_file);
+ dir_destroy (dir);
+ file_close (root_dir_file);
printf ("done.\n");
}
projects / pintos-anon / blobdiff