file.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 142 行

/*
 *  linux/fs/ext3/file.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([e-mail])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/file.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  ext3 fs regular file handling primitives
 *
 *  64-bit file support on 64-bit platforms by Jakub Jelinek
 *	([e-mail])
 */

#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd.h>
#include <linux/ext3_fs.h>
#include <linux/ext3_jbd.h>
#include "xattr.h"
#include "acl.h"

/*
 * Called when an inode is released. Note that this is different
 * from ext3_file_open: open gets called at every open, but release
 * gets called only when /all/ the files are closed.
 */
static int ext3_release_file (struct inode * inode, struct file * filp)
{
	if (filp->f_mode & FMODE_WRITE)
		ext3_discard_prealloc (inode);
	if (is_dx(inode) && filp->private_data)
		ext3_htree_free_dir_info(filp->private_data);

	return 0;
}

/*
 * Called when an inode is about to be opened.
 * We use this to disallow opening RW large files on 32bit systems if
 * the caller didn't specify O_LARGEFILE.  On 64bit systems we force
 * on this flag in sys_open.
 */
static int ext3_open_file (struct inode *inode, struct file *filp)
{
	if (!(filp->f_flags & O_LARGEFILE) &&
	    inode->i_size > 0x7FFFFFFFLL)
		return -EFBIG;
	return 0;
}

static ssize_t
ext3_file_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_dentry->d_inode;
	ssize_t ret;
	int err;

	ret = generic_file_aio_write(iocb, buf, count, pos);

	/*
	 * Skip flushing if there was an error, or if nothing was written.
	 */
	if (ret <= 0)
		return ret;

	/*
	 * If the inode is IS_SYNC, or is O_SYNC and we are doing data
	 * journalling then we need to make sure that we force the transaction
	 * to disk to keep all metadata uptodate synchronously.
	 */
	if (file->f_flags & O_SYNC) {
		/*
		 * If we are non-data-journaled, then the dirty data has
		 * already been flushed to backing store by generic_osync_inode,
		 * and the inode has been flushed too if there have been any
		 * modifications other than mere timestamp updates.
		 *
		 * Open question --- do we care about flushing timestamps too
		 * if the inode is IS_SYNC?
		 */
		if (!ext3_should_journal_data(inode))
			return ret;

		goto force_commit;
	}

	/*
	 * So we know that there has been no forced data flush.  If the inode
	 * is marked IS_SYNC, we need to force one ourselves.
	 */
	if (!IS_SYNC(inode))
		return ret;

	/*
	 * Open question #2 --- should we force data to disk here too?  If we
	 * don't, the only impact is that data=writeback filesystems won't
	 * flush data to disk automatically on IS_SYNC, only metadata (but
	 * historically, that is what ext2 has done.)
	 */

force_commit:
	err = ext3_force_commit(inode->i_sb);
	if (err) 
		return err;
	return ret;
}

struct file_operations ext3_file_operations = {
	.llseek		= generic_file_llseek,
	.read		= do_sync_read,
	.write		= do_sync_write,
	.aio_read	= generic_file_aio_read,
	.aio_write	= ext3_file_write,
	.readv		= generic_file_readv,
	.writev		= generic_file_writev,
	.ioctl		= ext3_ioctl,
	.mmap		= generic_file_mmap,
	.open		= ext3_open_file,
	.release	= ext3_release_file,
	.fsync		= ext3_sync_file,
	.sendfile	= generic_file_sendfile,
};

struct inode_operations ext3_file_inode_operations = {
	.truncate	= ext3_truncate,
	.setattr	= ext3_setattr,
	.setxattr	= ext3_setxattr,
	.getxattr	= ext3_getxattr,
	.listxattr	= ext3_listxattr,
	.removexattr	= ext3_removexattr,
	.permission	= ext3_permission,
};