filesys_SRC = filesys/filesys.c # Filesystem core.
filesys_SRC += filesys/file.c # Files.
filesys_SRC += filesys/directory.c # Directories.
-filesys_SRC += filesys/filehdr.c # File headers (inodes).
+filesys_SRC += filesys/inode.c # File headers.
filesys_SRC += filesys/fsutil.c # Utilities.
# User process code.
#include "filesys/fsutil.h"
#include "threads/malloc.h"
-/* Initializes D as a directory that holds ENTRY_CNT entries. */
-bool
-dir_init (struct dir *d, size_t entry_cnt)
+/* A directory. */
+struct dir
+ {
+ size_t entry_cnt; /* Number of entries. */
+ struct dir_entry *entries; /* Array of entries. */
+ };
+
+/* A single directory entry. */
+struct dir_entry
+ {
+ bool in_use; /* In use or free? */
+ char name[NAME_MAX + 1]; /* Null terminated file name. */
+ disk_sector_t inode_sector; /* Sector number of header. */
+ };
+
+/* Returns a new directory that holds ENTRY_CNT entries, if
+ successful, or a null pointer if memory is unavailable. */
+struct dir *
+dir_create (size_t entry_cnt)
{
- ASSERT (d != NULL);
- d->entry_cnt = entry_cnt;
- d->entries = calloc (1, sizeof *d->entries * entry_cnt);
- return d->entries != NULL;
+ struct dir *d = malloc (sizeof *d);
+ if (d != NULL)
+ {
+ d->entry_cnt = entry_cnt;
+ d->entries = calloc (1, sizeof *d->entries * entry_cnt);
+ if (d->entries != NULL)
+ return d;
+ free (d);
+ }
+ return NULL;
+}
+
+/* Returns the size, in bytes, of a directory with ENTRY_CNT
+ entries. */
+size_t
+dir_size (size_t entry_cnt)
+{
+ return entry_cnt * sizeof (struct dir_entry);
}
/* Destroys D and frees associated resources. */
dir_destroy (struct dir *d)
{
if (d != NULL)
- free (d->entries);
-}
-
-/* Returns the size of D in bytes. */
-static off_t
-dir_size (struct dir *d)
-{
- ASSERT (d != NULL);
- return d->entry_cnt * sizeof *d->entries;
+ {
+ free (d->entries);
+ free (d);
+ }
}
/* Reads D from FILE.
{
ASSERT (d != NULL);
ASSERT (file != NULL);
- ASSERT (file_length (file) >= dir_size (d));
+ ASSERT (file_length (file) >= (off_t) dir_size (d->entry_cnt));
- file_read_at (file, d->entries, dir_size (d), 0);
+ file_read_at (file, d->entries, dir_size (d->entry_cnt), 0);
}
/* Writes D to FILE.
void
dir_write (struct dir *d, struct file *file)
{
- file_write_at (file, d->entries, dir_size (d), 0);
+ file_write_at (file, d->entries, dir_size (d->entry_cnt), 0);
}
/* Searches D for a file named NAME.
/* Searches D for a file named NAME
and returns true if one exists, false otherwise.
- If FILEHDR_SECTOR is nonnull, then on success *FILEHDR_SECTOR
- is set to the sector that contains the file's header. */
+ If INODE_SECTOR is nonnull, then on success *INODE_SECTOR
+ is set to the sector that contains the file's inode. */
bool
dir_lookup (const struct dir *d, const char *name,
- disk_sector_t *filehdr_sector)
+ disk_sector_t *inode_sector)
{
const struct dir_entry *e;
e = lookup (d, name);
if (e != NULL)
{
- if (filehdr_sector != NULL)
- *filehdr_sector = e->filehdr_sector;
+ if (inode_sector != NULL)
+ *inode_sector = e->inode_sector;
return true;
}
else
}
/* Adds a file named NAME to D, which must not already contain a
- file by that name. The file's header is in sector
- FILEHDR_SECTOR.
+ file by that name. The file's inode is in sector
+ INODE_SECTOR.
Returns true if successful, false on failure.
Fails if NAME is invalid (i.e. too long) or if D has no free
directory entries. */
bool
-dir_add (struct dir *d, const char *name, disk_sector_t filehdr_sector)
+dir_add (struct dir *d, const char *name, disk_sector_t inode_sector)
{
size_t i;
{
e->in_use = true;
strlcpy (e->name, name, sizeof e->name);
- e->filehdr_sector = filehdr_sector;
+ e->inode_sector = inode_sector;
return true;
}
}
(This macro name comes from POSIX.1.) */
#define NAME_MAX 14
-/* A directory. */
-struct dir
- {
- size_t entry_cnt; /* Number of entries. */
- struct dir_entry *entries; /* Array of entries. */
- };
-
-/* A single directory entry. */
-struct dir_entry
- {
- bool in_use; /* In use or free? */
- char name[NAME_MAX + 1]; /* Null terminated file name. */
- disk_sector_t filehdr_sector; /* Sector number of header. */
- };
-
struct file;
-bool dir_init (struct dir *, size_t entry_cnt);
+struct dir *dir_create (size_t entry_cnt);
+size_t dir_size (size_t entry_cnt);
void dir_destroy (struct dir *);
void dir_read (struct dir *, struct file *);
void dir_write (struct dir *, struct file *);
#include <debug.h>
#include <string.h>
#include "filesys/directory.h"
-#include "filesys/filehdr.h"
+#include "filesys/inode.h"
#include "filesys/filesys.h"
#include "threads/malloc.h"
-bool
-file_open (struct file *file, disk_sector_t hdr_sector)
+/* An open file. */
+struct file
+ {
+ struct inode *inode; /* File's inode. */
+ uint8_t *bounce; /* Bounce buffer for reads and writes. */
+ off_t pos; /* Current position. */
+ };
+
+/* Opens and returns the file whose inode is in sector
+ INODE_SECTOR. Returns a null pointer if unsuccessful. */
+struct file *
+file_open (disk_sector_t inode_sector)
{
- file->hdr = filehdr_read (hdr_sector);
+ struct file *file = calloc (1, sizeof *file);
+ if (file == NULL)
+ return NULL;
+
+ file->inode = inode_open (inode_sector);
file->bounce = malloc (DISK_SECTOR_SIZE);
file->pos = 0;
- if (file->hdr != NULL && file->bounce != NULL)
- return true;
- else
+ if (file->inode == NULL || file->bounce == NULL)
{
- filehdr_destroy (file->hdr);
+ inode_close (file->inode);
free (file->bounce);
- return false;
+ return NULL;
}
+
+ return file;
}
+/* Closes FILE. */
void
file_close (struct file *file)
{
- filehdr_destroy (file->hdr);
+ if (file == NULL)
+ return;
+
+ inode_close (file->inode);
+ free (file->bounce);
}
+/* Reads SIZE bytes from FILE into BUFFER,
+ starting at the file's current position,
+ and advances the current position.
+ Returns the number of bytes actually read,
+ which may be less than SIZE if end of file is reached. */
off_t
file_read (struct file *file, void *buffer, off_t size)
{
return bytes_read;
}
+/* Reads SIZE bytes from FILE into BUFFER,
+ starting at offset FILE_OFS in the file.
+ The file's current position is unaffected
+ Returns the number of bytes actually read,
+ which may be less than SIZE if end of file is reached. */
off_t
file_read_at (struct file *file, void *buffer_, off_t size,
off_t file_ofs)
while (size > 0)
{
/* Disk sector to read, starting byte offset within sector. */
- off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
+ off_t sector_idx = inode_byte_to_sector (file->inode, file_ofs);
int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
/* Bytes left in file, bytes left in sector, lesser of the two. */
- off_t file_left = filehdr_length (file->hdr) - file_ofs;
+ off_t file_left = inode_length (file->inode) - file_ofs;
int sector_left = DISK_SECTOR_SIZE - sector_ofs;
int min_left = file_left < sector_left ? file_left : sector_left;
return bytes_read;
}
+/* Writes SIZE bytes from BUFFER into FILE,
+ starting at the file's current position,
+ and advances the current position.
+ Returns the number of bytes actually written,
+ which may be less than SIZE if end of file is reached.
+ (Normally we'd grow the file in that case, but file growth is
+ not yet implemented.) */
off_t
file_write (struct file *file, const void *buffer, off_t size)
{
return bytes_written;
}
+/* Writes SIZE bytes from BUFFER into FILE,
+ starting at offset FILE_OFS in the file.
+ The file's current position is unaffected
+ Returns the number of bytes actually written,
+ which may be less than SIZE if end of file is reached.
+ (Normally we'd grow the file in that case, but file growth is
+ not yet implemented.) */
off_t
file_write_at (struct file *file, const void *buffer_, off_t size,
off_t file_ofs)
while (size > 0)
{
/* Starting byte offset within sector to read. */
- off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
+ off_t sector_idx = inode_byte_to_sector (file->inode, file_ofs);
int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
/* Bytes left in file, bytes left in sector, lesser of the two. */
- off_t file_left = filehdr_length (file->hdr) - file_ofs;
+ off_t file_left = inode_length (file->inode) - file_ofs;
int sector_left = DISK_SECTOR_SIZE - sector_ofs;
int min_left = file_left < sector_left ? file_left : sector_left;
return bytes_written;
}
+/* Returns the size of FILE in bytes. */
off_t
file_length (struct file *file)
{
ASSERT (file != NULL);
- return filehdr_length (file->hdr);
+ return inode_length (file->inode);
}
+/* Sets the current position in FILE to an offset of FILE_OFS
+ bytes from the start of the file. */
void
file_seek (struct file *file, off_t file_ofs)
{
file->pos = file_ofs;
}
+/* Returns the current position in FILE as a byte offset from the
+ start of the file. */
off_t
file_tell (struct file *file)
{
#ifndef FILESYS_FILE_H
#define FILESYS_FILE_H
-#include <stdbool.h>
-#include <stdint.h>
#include <stddef.h>
#include "devices/disk.h"
#include "filesys/off_t.h"
-struct file
- {
- struct filehdr *hdr;
- void *bounce;
- off_t pos;
- };
-
-bool file_open (struct file *, disk_sector_t);
+struct file *file_open (disk_sector_t);
void file_close (struct file *);
off_t file_read (struct file *, void *, off_t);
off_t file_read_at (struct file *, void *, off_t size, off_t start);
off_t file_length (struct file *);
void file_seek (struct file *, off_t);
off_t file_tell (struct file *);
+void file_remove (struct file *);
#endif /* filesys/file.h */
+++ /dev/null
-#include "filesys/filehdr.h"
-#include <bitmap.h>
-#include <debug.h>
-#include <stdio.h>
-#include "filesys/filesys.h"
-#include "threads/malloc.h"
-
-/* Allocates sectors from bitmap B for the content of a file
- whose size is LENGTH bytes, and returns a new `struct filehdr'
- properly initialized for the file.
- It is the caller's responsible to allocate a sector for the
- file header itself, and to write the file header and bitmap
- to disk.
- If memory or disk allocation fails, returns a null pointer,
- leaving bitmap B is unchanged. */
-struct filehdr *
-filehdr_allocate (struct bitmap *b, off_t length)
-{
- struct filehdr *h;
- size_t sector_cnt;
-
- ASSERT (b != NULL);
- ASSERT (length >= 0);
-
- sector_cnt = (length / DISK_SECTOR_SIZE) + (length % DISK_SECTOR_SIZE > 0);
- if (sector_cnt > DIRECT_CNT)
- return false;
-
- h = calloc (1, sizeof *h);
- if (h == NULL)
- return NULL;
-
- h->length = length;
- while (h->sector_cnt < sector_cnt)
- {
- size_t sector = bitmap_find_and_set (b);
- if (sector == BITMAP_ERROR)
- {
- filehdr_deallocate (h, b);
- free (h);
- return NULL;
- }
- h->sectors[h->sector_cnt++] = sector;
- }
-
- return h;
-}
-
-/* Marks the sectors for H's content as free in bitmap B.
- Neither H's own disk sector nor its memory are freed. */
-void
-filehdr_deallocate (struct filehdr *h, struct bitmap *b)
-{
- size_t i;
-
- ASSERT (h != NULL);
- ASSERT (b != NULL);
-
- for (i = 0; i < h->sector_cnt; i++)
- bitmap_reset (b, h->sectors[i]);
-}
-
-/* Reads a file header from FILEHDR_SECTOR
- and returns a new `struct filehdr' that contains it.
- Returns a null pointer fi memory allocation fails. */
-struct filehdr *
-filehdr_read (disk_sector_t filehdr_sector)
-{
- struct filehdr *h = calloc (1, sizeof *h);
- if (h == NULL)
- return NULL;
-
- ASSERT (sizeof *h == DISK_SECTOR_SIZE);
- disk_read (filesys_disk, filehdr_sector, h);
-
- return h;
-}
-
-/* Writes H to disk in sector FILEHDR_SECTOR. */
-void
-filehdr_write (const struct filehdr *h, disk_sector_t filehdr_sector)
-{
- ASSERT (h != NULL);
- ASSERT (sizeof *h == DISK_SECTOR_SIZE);
- disk_write (filesys_disk, filehdr_sector, h);
-}
-
-/* Frees the memory (but not the on-disk sector) associated with
- H. */
-void
-filehdr_destroy (struct filehdr *h)
-{
- free (h);
-}
-
-/* Returns the disk sector that contains byte offset POS within
- the file with header H.
- Returns -1 if H does not contain data for a byte at offset
- POS. */
-disk_sector_t
-filehdr_byte_to_sector (const struct filehdr *h, off_t pos)
-{
- size_t idx;
-
- ASSERT (h != NULL);
-
- idx = pos / DISK_SECTOR_SIZE;
- return idx < h->sector_cnt ? h->sectors[idx] : (disk_sector_t) -1;
-}
-
-/* Returns the length, in bytes, of the file with header H, */
-off_t
-filehdr_length (const struct filehdr *h)
-{
- ASSERT (h != NULL);
- return h->length;
-}
-
-/* Prints a representation of H to the system console. */
-void
-filehdr_print (const struct filehdr *h)
-{
- size_t i;
-
- printf ("File header: %jd bytes, %zd sectors (",
- (intmax_t) h->length, h->sector_cnt);
-
- /* This loop could be unsafe for large h->sector_cnt, can you
- see why? */
- for (i = 0; i < h->sector_cnt; i++)
- {
- if (i != 0)
- printf (", ");
- printf ("%jd", (intmax_t) h->sectors[i]);
- }
- printf (")\n");
-}
+++ /dev/null
-#ifndef FILESYS_FILEHDR_H
-#define FILESYS_FILEHDR_H
-
-#include <stdbool.h>
-#include <stddef.h>
-#include "filesys/off_t.h"
-#include "devices/disk.h"
-
-/* Number of direct sector pointers in a file header. */
-#define DIRECT_CNT ((DISK_SECTOR_SIZE - sizeof (off_t) * 2) \
- / sizeof (disk_sector_t))
-
-/* File header.
- This is both an in-memory and on-disk structure. */
-struct filehdr
- {
- off_t length; /* File size in bytes. */
- size_t sector_cnt; /* File size in sectors. */
- disk_sector_t sectors[DIRECT_CNT]; /* Sectors allocated for file. */
- };
-
-struct bitmap;
-struct filehdr *filehdr_allocate (struct bitmap *, off_t length);
-void filehdr_deallocate (struct filehdr *, struct bitmap *);
-struct filehdr *filehdr_read (disk_sector_t);
-void filehdr_write (const struct filehdr *, disk_sector_t);
-void filehdr_destroy (struct filehdr *);
-disk_sector_t filehdr_byte_to_sector (const struct filehdr *, off_t);
-off_t filehdr_length (const struct filehdr *);
-void filehdr_print (const struct filehdr *);
-
-#endif /* filesys/filehdr.h */
#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");
}
#define FILESYS_FILESYS_H
#include <stdbool.h>
-#include <stdint.h>
#include "filesys/off_t.h"
/* Disk used for filesystem. */
extern struct disk *filesys_disk;
-struct file;
+/* The free map file, opened by filesys_init() and never
+ closed. */
+extern struct file *free_map_file;
+
void filesys_init (bool format);
bool filesys_create (const char *name, off_t initial_size);
-bool filesys_open (const char *name, struct file *);
+struct file *filesys_open (const char *name);
bool filesys_remove (const char *name);
bool filesys_list (void);
bool filesys_dump (void);
copy (const char *filename, off_t size)
{
struct disk *src;
- struct file dst;
+ struct file *dst;
disk_sector_t sector;
void *buffer;
/* Create destination file. */
if (!filesys_create (filename, size))
PANIC ("%s: create failed", filename);
- if (!filesys_open (filename, &dst))
+ dst = filesys_open (filename);
+ if (dst == NULL)
PANIC ("%s: open failed", filename);
/* Do copy. */
{
int chunk_size = size > DISK_SECTOR_SIZE ? DISK_SECTOR_SIZE : size;
disk_read (src, sector++, buffer);
- if (file_write (&dst, buffer, chunk_size) != chunk_size)
+ if (file_write (dst, buffer, chunk_size) != chunk_size)
PANIC ("%s: write failed with %lld bytes unwritten",
filename, (unsigned long long) size);
size -= chunk_size;
}
palloc_free (buffer);
- file_close (&dst);
+ file_close (dst);
}
/* Executes the filesystem operations described by the variables
void
fsutil_print (const char *filename)
{
- struct file file;
+ struct file *file;
char *buffer;
- if (!filesys_open (filename, &file))
+ file = filesys_open (filename);
+ if (file == NULL)
PANIC ("%s: open failed", filename);
buffer = palloc_get (PAL_ASSERT);
for (;;)
{
- off_t n = file_read (&file, buffer, PGSIZE);
+ off_t n = file_read (file, buffer, PGSIZE);
if (n == 0)
break;
hex_dump (buffer, n, true);
}
palloc_free (buffer);
- file_close (&file);
+ file_close (file);
}
--- /dev/null
+#include "filesys/inode.h"
+#include <bitmap.h>
+#include <list.h>
+#include <debug.h>
+#include <stdio.h>
+#include "filesys/filesys.h"
+#include "threads/malloc.h"
+
+/* Number of direct sector pointers in an inode. */
+#define DIRECT_CNT ((DISK_SECTOR_SIZE - sizeof (off_t) - sizeof (size_t)) \
+ / sizeof (disk_sector_t))
+
+/* On-disk inode.
+ It is exactly DISK_SECTOR_SIZE bytes long. */
+struct inode_disk
+ {
+ off_t length; /* File size in bytes. */
+ size_t sector_cnt; /* File size in sectors. */
+ disk_sector_t sectors[DIRECT_CNT]; /* Sectors allocated for file. */
+ };
+
+/* In-memory inode. */
+struct inode
+ {
+ list_elem elem; /* Element in inode list. */
+ disk_sector_t sector; /* Sector number of disk location. */
+ int open_cnt; /* Number of openers. */
+ bool removed; /* True if deleted, false otherwise. */
+ struct inode_disk data; /* On-disk data. */
+ };
+
+/* List of open inodes, so that opening a single inode twice
+ returns the same `struct inode'. */
+struct list open_inodes;
+
+static struct inode *alloc_inode (disk_sector_t);
+
+/* Initializes the inode module. */
+void
+inode_init (void)
+{
+ list_init (&open_inodes);
+}
+
+/* Allocates sectors from bitmap B for the content of a file
+ whose size is LENGTH bytes, and returns a new `struct inode'
+ properly initialized for the file.
+ It is the caller's responsible to write the inode to disk with
+ inode_commit(), as well as the bitmap.
+ If memory or disk allocation fails, returns a null pointer,
+ leaving bitmap B is unchanged. */
+struct inode *
+inode_create (struct bitmap *b, disk_sector_t sector, off_t length)
+{
+ struct inode *idx;
+ size_t sector_cnt;
+
+ ASSERT (b != NULL);
+ ASSERT (length >= 0);
+
+ /* Calculate number of sectors to allocate for file data. */
+ sector_cnt = (length / DISK_SECTOR_SIZE) + (length % DISK_SECTOR_SIZE > 0);
+ if (sector_cnt > DIRECT_CNT)
+ return NULL;
+
+ /* Allocate inode. */
+ idx = alloc_inode (sector);
+ if (idx == NULL)
+ return NULL;
+
+ /* Allocate disk sectors. */
+ idx->data.length = length;
+ while (idx->data.sector_cnt < sector_cnt)
+ {
+ size_t sector = bitmap_find_and_set (b);
+ if (sector == BITMAP_ERROR)
+ goto error;
+
+ idx->data.sectors[idx->data.sector_cnt++] = sector;
+ }
+
+ /* Zero out the file contents. */
+ if (sector_cnt > 0)
+ {
+ void *zero_sector;
+ size_t i;
+
+ zero_sector = calloc (1, DISK_SECTOR_SIZE);
+ if (zero_sector == NULL)
+ goto error;
+ for (i = 0; i < sector_cnt; i++)
+ disk_write (filesys_disk, idx->data.sectors[i], zero_sector);
+ free (zero_sector);
+ }
+
+ return idx;
+
+ error:
+ inode_remove (idx);
+ inode_close (idx);
+ return NULL;
+}
+
+/* Reads an inode from SECTOR
+ and returns a `struct inode' that contains it.
+ Returns a null pointer if memory allocation fails. */
+struct inode *
+inode_open (disk_sector_t sector)
+{
+ list_elem *e;
+ struct inode *idx;
+
+ /* Check whether this inode is already open. */
+ for (e = list_begin (&open_inodes); e != list_end (&open_inodes);
+ e = list_next (e))
+ {
+ idx = list_entry (e, struct inode, elem);
+ if (idx->sector == sector)
+ {
+ idx->open_cnt++;
+ return idx;
+ }
+ }
+
+ /* Allocate inode. */
+ idx = alloc_inode (sector);
+ if (idx == NULL)
+ return NULL;
+
+ /* Read from disk. */
+ ASSERT (sizeof idx->data == DISK_SECTOR_SIZE);
+ disk_read (filesys_disk, sector, &idx->data);
+
+ return idx;
+}
+
+/* Closes inode IDX and writes it to disk.
+ If this was the last reference to IDX, frees its memory.
+ If IDX was also a removed inode, frees its blocks. */
+void
+inode_close (struct inode *idx)
+{
+ if (idx == NULL)
+ return;
+
+ if (--idx->open_cnt == 0)
+ {
+ if (idx->removed)
+ {
+ struct bitmap *free_map;
+ size_t i;
+
+ free_map = bitmap_create (disk_size (filesys_disk));
+ if (free_map != NULL)
+ {
+ bitmap_read (free_map, free_map_file);
+
+ bitmap_reset (free_map, idx->sector);
+ for (i = 0; i < idx->data.sector_cnt; i++)
+ bitmap_reset (free_map, idx->data.sectors[i]);
+
+ bitmap_write (free_map, free_map_file);
+ bitmap_destroy (free_map);
+ }
+ else
+ printf ("inode_close(): can't free blocks");
+ }
+ list_remove (&idx->elem);
+ free (idx);
+ }
+}
+
+/* Writes IDX to disk. */
+void
+inode_commit (const struct inode *idx)
+{
+ ASSERT (idx != NULL);
+ ASSERT (sizeof idx->data == DISK_SECTOR_SIZE);
+ disk_write (filesys_disk, idx->sector, &idx->data);
+}
+
+/* Marks IDX to be deleted when it is closed by the last caller who
+ has it open. */
+void
+inode_remove (struct inode *idx)
+{
+ ASSERT (idx != NULL);
+ idx->removed = true;
+}
+
+/* Returns the disk sector that contains byte offset POS within
+ the file with inode IDX.
+ Returns -1 if IDX does not contain data for a byte at offset
+ POS. */
+disk_sector_t
+inode_byte_to_sector (const struct inode *idx, off_t pos)
+{
+ size_t i;
+
+ ASSERT (idx != NULL);
+
+ i = pos / DISK_SECTOR_SIZE;
+ return i < idx->data.sector_cnt ? idx->data.sectors[i] : (disk_sector_t) -1;
+}
+
+/* Returns the length, in bytes, of the file with inode IDX. */
+off_t
+inode_length (const struct inode *idx)
+{
+ ASSERT (idx != NULL);
+ return idx->data.length;
+}
+
+/* Prints a representation of IDX to the system console. */
+void
+inode_print (const struct inode *idx)
+{
+ size_t i;
+
+ printf ("Inode %"PRDSNu": %"PRDSNu" bytes, %zd sectors (",
+ idx->sector, idx->data.length, idx->data.sector_cnt);
+
+ /* This loop could be unsafe for large idx->data.sector_cnt, can
+ you see why? */
+ for (i = 0; i < idx->data.sector_cnt; i++)
+ {
+ if (i != 0)
+ printf (", ");
+ printf ("%"PRDSNu, idx->data.sectors[i]);
+ }
+ printf (")\n");
+}
+\f
+/* Returns a newly allocated and initialized inode. */
+static struct inode *
+alloc_inode (disk_sector_t sector)
+{
+ /* Allocate memory. */
+ struct inode *idx = calloc (1, sizeof *idx);
+ if (idx == NULL)
+ return NULL;
+
+ /* Initialize. */
+ list_push_front (&open_inodes, &idx->elem);
+ idx->sector = sector;
+ idx->open_cnt = 1;
+ idx->removed = false;
+
+ return idx;
+}
--- /dev/null
+#ifndef FILESYS_INODE_H
+#define FILESYS_INODE_H
+
+#include "filesys/off_t.h"
+#include "devices/disk.h"
+
+struct bitmap;
+
+void inode_init (void);
+struct inode *inode_create (struct bitmap *, disk_sector_t, off_t);
+struct inode *inode_open (disk_sector_t);
+void inode_close (struct inode *);
+void inode_commit (const struct inode *);
+void inode_remove (struct inode *);
+disk_sector_t inode_byte_to_sector (const struct inode *, off_t);
+off_t inode_length (const struct inode *);
+void inode_print (const struct inode *);
+
+#endif /* filesys/inode.h */
addrspace_load (struct thread *t, const char *filename, void (**start) (void))
{
struct Elf32_Ehdr ehdr;
- struct file file;
- bool file_open = false;
+ struct file *file = NULL;
off_t file_ofs;
bool success = false;
int i;
LOAD_ERROR (("page directory allocation failed"));
/* Open executable file. */
- file_open = filesys_open (filename, &file);
- if (!file_open)
+ file = filesys_open (filename);
+ if (file == NULL)
LOAD_ERROR (("open failed"));
/* Read and verify executable header. */
- if (file_read (&file, &ehdr, sizeof ehdr) != sizeof ehdr)
+ if (file_read (file, &ehdr, sizeof ehdr) != sizeof ehdr)
LOAD_ERROR (("error reading executable header"));
if (memcmp (ehdr.e_ident, "\177ELF\1\1\1", 7) != 0)
LOAD_ERROR (("file is not ELF"));
{
struct Elf32_Phdr phdr;
- file_seek (&file, file_ofs);
- if (file_read (&file, &phdr, sizeof phdr) != sizeof phdr)
+ file_seek (file, file_ofs);
+ if (file_read (file, &phdr, sizeof phdr) != sizeof phdr)
LOAD_ERROR (("error reading program header"));
file_ofs += sizeof phdr;
switch (phdr.p_type)
printf ("unknown ELF segment type %08x\n", phdr.p_type);
break;
case PT_LOAD:
- if (!load_segment (t, &file, &phdr))
+ if (!load_segment (t, file, &phdr))
goto done;
break;
}
done:
/* We arrive here whether the load is successful or not.
We can distinguish based on `success'. */
- if (file_open)
- file_close (&file);
+ file_close (file);
if (!success)
addrspace_destroy (t);
return success;
file into the page and zero the rest. */
size_t read_bytes = filesz_left >= PGSIZE ? PGSIZE : filesz_left;
size_t zero_bytes = PGSIZE - read_bytes;
- uint8_t *kpage = palloc_get (0);
+ uint8_t *kpage = palloc_get (PAL_USER);
if (kpage == NULL)
return false;
uint8_t *kpage;
bool success = false;
- kpage = palloc_get (PAL_ZERO);
+ kpage = palloc_get (PAL_USER | PAL_ZERO);
if (kpage != NULL)
{
success = install_page (t, ((uint8_t *) PHYS_BASE) - PGSIZE, kpage);
projects / pintos-anon / commitdiff