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Revision a247c3a97a0216b18a46243eda26081f1928ec37 authored by Andrea Arcangeli on 22 September 2010, 20:05:12 UTC, committed by Linus Torvalds on 23 September 2010, 00:22:39 UTC 
rmap: fix walk during fork
 
The below bug in fork led to the rmap walk finding the parent huge-pmd
twice instead of just once, because the anon_vma_chain objects of the
child vma still point to the vma->vm_mm of the parent.

The patch fixes it by making the rmap walk accurate during fork.  It's not
a big deal normally but it worth being accurate considering the cost is
the same.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent df08cdc
Raw File
file.c 
/*
 *  linux/fs/ext3/file.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * 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
 *	(jj@sunsite.ms.mff.cuni.cz)
 */

#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd.h>
#include <linux/quotaops.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 (ext3_test_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE)) {
		filemap_flush(inode->i_mapping);
		ext3_clear_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
	}
	/* if we are the last writer on the inode, drop the block reservation */
	if ((filp->f_mode & FMODE_WRITE) &&
			(atomic_read(&inode->i_writecount) == 1))
	{
		mutex_lock(&EXT3_I(inode)->truncate_mutex);
		ext3_discard_reservation(inode);
		mutex_unlock(&EXT3_I(inode)->truncate_mutex);
	}
	if (is_dx(inode) && filp->private_data)
		ext3_htree_free_dir_info(filp->private_data);

	return 0;
}

const 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	= generic_file_aio_write,
	.unlocked_ioctl	= ext3_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= ext3_compat_ioctl,
#endif
	.mmap		= generic_file_mmap,
	.open		= dquot_file_open,
	.release	= ext3_release_file,
	.fsync		= ext3_sync_file,
	.splice_read	= generic_file_splice_read,
	.splice_write	= generic_file_splice_write,
};

const struct inode_operations ext3_file_inode_operations = {
	.truncate	= ext3_truncate,
	.setattr	= ext3_setattr,
#ifdef CONFIG_EXT3_FS_XATTR
	.setxattr	= generic_setxattr,
	.getxattr	= generic_getxattr,
	.listxattr	= ext3_listxattr,
	.removexattr	= generic_removexattr,
#endif
	.check_acl	= ext3_check_acl,
	.fiemap		= ext3_fiemap,
};
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