fs-ecos.c

带ＳＤ卡的ＬＩＮＵＸ根文件系统． 在ＡＲＭ上应用

	if (err == 0)
		ds1.node->i_ctime =
		    ds2.dir->i_ctime = ds2.dir->i_mtime = cyg_timestamp();

	return err;
}

// -------------------------------------------------------------------------
// jffs2_opendir()
// Open a directory for reading.

static int jffs2_opendir(cyg_mtab_entry * mte, cyg_dir dir, const char *name,
			 cyg_file * file)
{
	jffs2_dirsearch ds;
	int err;

	D2(printf("jffs2_opendir\n"));

	icache_evict((struct inode *) mte->root, (struct inode *) dir);

	init_dirsearch(&ds, (struct inode *) dir, name);

	err = jffs2_find(&ds);

	if (err != ENOERR)
		return err;

	// check it is really a directory.
	if (!S_ISDIR(ds.node->i_mode))
		return ENOTDIR;

	ds.node->i_count++;	// Count successful open

	// Initialize the file object, setting the f_ops field to a
	// special set of file ops.

	file->f_type = CYG_FILE_TYPE_FILE;
	file->f_ops = &jffs2_dirops;
	file->f_offset = 0;
	file->f_data = (CYG_ADDRWORD) ds.node;
	file->f_xops = 0;

	return ENOERR;

}

// -------------------------------------------------------------------------
// jffs2_chdir()
// Change directory support.

static int jffs2_chdir(cyg_mtab_entry * mte, cyg_dir dir, const char *name,
		       cyg_dir * dir_out)
{
	D2(printf("jffs2_chdir\n"));

	if (dir_out != NULL) {
		// This is a request to get a new directory pointer in
		// *dir_out.

		jffs2_dirsearch ds;
		int err;

		icache_evict((struct inode *) mte->root, (struct inode *) dir);

		init_dirsearch(&ds, (struct inode *) dir, name);

		err = jffs2_find(&ds);

		if (err != ENOERR)
			return err;

		// check it is a directory
		if (!S_ISDIR(ds.node->i_mode))
			return ENOTDIR;

		// Increment ref count to keep this directory in existance
		// while it is the current cdir.
		ds.node->i_count++;

		// Pass it out
		*dir_out = (cyg_dir) ds.node;
	} else {
		// If no output dir is required, this means that the mte and
		// dir arguments are the current cdir setting and we should
		// forget this fact.

		struct inode *node = (struct inode *) dir;

		// Just decrement directory reference count.
		dec_refcnt(node);
	}

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_stat()
// Get struct stat info for named object.

static int jffs2_stat(cyg_mtab_entry * mte, cyg_dir dir, const char *name,
		      struct stat *buf)
{
	jffs2_dirsearch ds;
	int err;

	D2(printf("jffs2_stat\n"));

	icache_evict((struct inode *) mte->root, (struct inode *) dir);

	init_dirsearch(&ds, (struct inode *) dir, name);

	err = jffs2_find(&ds);

	if (err != ENOERR)
		return err;

	// Fill in the status
	buf->st_mode = ds.node->i_mode;
	buf->st_ino = (ino_t) ds.node;
	buf->st_dev = 0;
	buf->st_nlink = ds.node->i_nlink;
	buf->st_uid = 0;
	buf->st_gid = 0;
	buf->st_size = ds.node->i_size;
	buf->st_atime = ds.node->i_atime;
	buf->st_mtime = ds.node->i_mtime;
	buf->st_ctime = ds.node->i_ctime;

	return err;

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_getinfo()
// Getinfo. Currently only support pathconf().

static int jffs2_getinfo(cyg_mtab_entry * mte, cyg_dir dir, const char *name,
			 int key, void *buf, int len)
{
	jffs2_dirsearch ds;
	int err;

	D2(printf("jffs2_getinfo\n"));

	icache_evict((struct inode *) mte->root, (struct inode *) dir);

	init_dirsearch(&ds, (struct inode *) dir, name);

	err = jffs2_find(&ds);

	if (err != ENOERR)
		return err;

	switch (key) {
	case FS_INFO_CONF:
		err = jffs2_pathconf(ds.node, (struct cyg_pathconf_info *) buf);
		break;

	default:
		err = EINVAL;
	}
	return err;

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_setinfo()
// Setinfo. Nothing to support here at present.

static int jffs2_setinfo(cyg_mtab_entry * mte, cyg_dir dir, const char *name,
			 int key, void *buf, int len)
{
	// No setinfo keys supported at present

	D2(printf("jffs2_setinfo\n"));

	return EINVAL;
}

//==========================================================================
// File operations

// -------------------------------------------------------------------------
// jffs2_fo_read()
// Read data from the file.

static int jffs2_fo_read(struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio)
{
	struct inode *inode = (struct inode *) fp->f_data;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	int i;
	ssize_t resid = uio->uio_resid;
	off_t pos = fp->f_offset;

	down(&f->sem);

	// Loop over the io vectors until there are none left
	for (i = 0; i < uio->uio_iovcnt && pos < inode->i_size; i++) {
		int ret;
		cyg_iovec *iov = &uio->uio_iov[i];
		off_t len = min(iov->iov_len, inode->i_size - pos);

		D2(printf("jffs2_fo_read inode size %d\n", inode->i_size));

		ret =
		    jffs2_read_inode_range(c, f,
					   (unsigned char *) iov->iov_base, pos,
					   len);
		if (ret) {
			D1(printf
			   ("jffs2_fo_read(): read_inode_range failed %d\n",
			    ret));
			uio->uio_resid = resid;
			up(&f->sem);
			return -ret;
		}
		resid -= len;
		pos += len;
	}

	// We successfully read some data, update the node's access time
	// and update the file offset and transfer residue.

	inode->i_atime = cyg_timestamp();

	uio->uio_resid = resid;
	fp->f_offset = pos;

	up(&f->sem);

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_fo_write()
// Write data to file.

static int jffs2_fo_write(struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio)
{
	struct page write_page;
	off_t page_start_pos;
	struct inode *node = (struct inode *) fp->f_data;
	off_t pos = fp->f_offset;
	ssize_t resid = uio->uio_resid;
	int i;

	memset(&read_write_buffer, 0, PAGE_CACHE_SIZE);
	write_page.virtual = &read_write_buffer;

	// If the APPEND mode bit was supplied, force all writes to
	// the end of the file.
	if (fp->f_flag & CYG_FAPPEND)
		pos = fp->f_offset = node->i_size;

	// Check that pos is within current file size, or at the very end.
	if (pos < 0 || pos > node->i_size)
		return EINVAL;

	// Now loop over the iovecs until they are all done, or
	// we get an error.
	for (i = 0; i < uio->uio_iovcnt; i++) {
		cyg_iovec *iov = &uio->uio_iov[i];
		char *buf = (char *) iov->iov_base;
		off_t len = iov->iov_len;

		// loop over the vector writing it to the file until it has
		// all been done.
		while (len > 0) {
			//cyg_uint8 *fbuf;
			//size_t bsize;
			size_t writtenlen;
			off_t l = len;
			int err;

			write_page.index = 0;

			page_start_pos = pos;
			while (page_start_pos >= (PAGE_CACHE_SIZE)) {
				write_page.index++;
				page_start_pos -= PAGE_CACHE_SIZE;
			}

			if (l > PAGE_CACHE_SIZE - page_start_pos)
				l = PAGE_CACHE_SIZE - page_start_pos;

			D2(printf
			   ("jffs2_fo_write write_page.index %d\n",
			    write_page.index));
			D2(printf
			   ("jffs2_fo_write page_start_pos %d\n",
			    page_start_pos));
			D2(printf("jffs2_fo_write transfer size %d\n", l));

			err =
			    jffs2_prepare_write(node, &write_page,
						page_start_pos,
						page_start_pos + l);

			if (err != 0)
				return err;

			// copy data in
			memcpy(&read_write_buffer[page_start_pos], buf, l);

			writtenlen =
			    jffs2_commit_write(node, &write_page,
					       page_start_pos,
					       page_start_pos + l);

			if (writtenlen != l)
				return ENOSPC;

			// Update working vars
			len -= l;
			buf += l;
			pos += l;
			resid -= l;
		}
	}

	// We wrote some data successfully, update the modified and access
	// times of the node, increase its size appropriately, and update
	// the file offset and transfer residue.
	node->i_mtime = node->i_ctime = cyg_timestamp();
	if (pos > node->i_size)
		node->i_size = pos;

	uio->uio_resid = resid;
	fp->f_offset = pos;

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_fo_lseek()
// Seek to a new file position.

static int jffs2_fo_lseek(struct CYG_FILE_TAG *fp, off_t * apos, int whence)
{
	struct inode *node = (struct inode *) fp->f_data;
	off_t pos = *apos;

	D2(printf("jffs2_fo_lseek\n"));

	switch (whence) {
	case SEEK_SET:
		// Pos is already where we want to be.
		break;

	case SEEK_CUR:
		// Add pos to current offset.
		pos += fp->f_offset;
		break;

	case SEEK_END:
		// Add pos to file size.
		pos += node->i_size;
		break;

	default:
		return EINVAL;
	}

	// Check that pos is still within current file size, or at the
	// very end.
	if (pos < 0 || pos > node->i_size)
		return EINVAL;

	// All OK, set fp offset and return new position.
	*apos = fp->f_offset = pos;

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_fo_ioctl()
// Handle ioctls. Currently none are defined.

static int jffs2_fo_ioctl(struct CYG_FILE_TAG *fp, CYG_ADDRWORD com,
			  CYG_ADDRWORD data)
{
	// No Ioctls currenly defined.

	D2(printf("jffs2_fo_ioctl\n"));

	return EINVAL;
}

// -------------------------------------------------------------------------
// jffs2_fo_fsync().
// Force the file out to data storage.

static int jffs2_fo_fsync(struct CYG_FILE_TAG *fp, int mode)
{
	// Data is always permanently where it belongs, nothing to do
	// here.

	D2(printf("jffs2_fo_fsync\n"));

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_fo_close()
// Close a file. We just decrement the refcnt and let it go away if
// that is all that is keeping it here.

static int jffs2_fo_close(struct CYG_FILE_TAG *fp)
{
	struct inode *node = (struct inode *) fp->f_data;

	D2(printf("jffs2_fo_close\n"));

	dec_refcnt(node);

	fp->f_data = 0;		// zero data pointer

	return ENOERR;
}

// -------------------------------------------------------------------------
//jffs2_fo_fstat()
// Get file status.

static int jffs2_fo_fstat(struct CYG_FILE_TAG *fp, struct stat *buf)
{
	struct inode *node = (struct inode *) fp->f_data;

	D2(printf("jffs2_fo_fstat\n"));

	// Fill in the status
	buf->st_mode = node->i_mode;
	buf->st_ino = (ino_t) node;
	buf->st_dev = 0;
	buf->st_nlink = node->i_nlink;
	buf->st_uid = 0;
	buf->st_gid = 0;
	buf->st_size = node->i_size;
	buf->st_atime = node->i_atime;
	buf->st_mtime = node->i_mtime;
	buf->st_ctime = node->i_ctime;

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_fo_getinfo()
// Get info. Currently only supports fpathconf().

static int jffs2_fo_getinfo(struct CYG_FILE_TAG *fp, int key, void *buf,
			    int len)
{
	struct inode *node = (struct inode *) fp->f_data;
	int err;

	D2(printf("jffs2_fo_getinfo\n"));

	switch (key) {
	case FS_INFO_CONF:
		err = jffs2_pathconf(node, (struct cyg_pathconf_info *) buf);
		break;

	default:
		err = EINVAL;
	}
	return err;

	return ENOERR;
}

// -------------------------------------------------------------------------
// jffs2_fo_setinfo()
// Set info. Nothing supported here.

static int jffs2_fo_setinfo(struct CYG_FILE_TAG *fp, int key, void *buf,
			    int len)
{
	// No setinfo key supported at present

	D2(printf("jffs2_fo_setinfo\n"));

	return ENOERR;
}

//==========================================================================
// Directory operations

// -------------------------------------------------------------------------
// jffs2_fo_dirread()
// Read a single directory entry from a file.

static __inline void filldir(char *nbuf, int nlen, const char *name, int namlen)
{
	int len = nlen < namlen ? nlen : namlen;
	memcpy(nbuf, name, len);
	nbuf[len] = '\0';
}

static int jffs2_fo_dirread(struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio)
{
	struct inode *d_inode = (struct inode *) fp->f_data;
	struct dirent *ent = (struct dirent *) uio->uio_iov[0].iov_base;
	char *nbuf = ent->d_name;
	int nlen = sizeof (ent->d_name) - 1;
	off_t len = uio->uio_iov[0].iov_len;
	struct jffs2_inode_info *f;
	struct jffs2_sb_info *c;
	struct inode *inode = d_inode;
	struct jffs2_full_dirent *fd;