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Revision e1cbbfa5f5aaf40a1fe70856fac4dfcc33e0e651 authored by Josef Bacik on 17 March 2015, 14:52:28 UTC, committed by Josef Bacik on 17 March 2015, 20:36:35 UTC 
Btrfs: fix outstanding_extents accounting in DIO
 
We are keeping track of how many extents we need to reserve properly based on
the amount we want to write, but we were still incrementing outstanding_extents
if we wrote less than what we requested.  This isn't quite right since we will
be limited to our max extent size.  So instead lets do something horrible!  Keep
track of how many outstanding_extents we reserved, and decrement each time we
allocate an extent.  If we use our entire reserve make sure to jack up
outstanding_extents on the inode so the accounting works out properly.  Thanks,

Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
1 parent 6a3891c
Raw File
xip.c 
/*
 *  linux/fs/ext2/xip.c
 *
 * Copyright (C) 2005 IBM Corporation
 * Author: Carsten Otte (cotte@de.ibm.com)
 */

#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include "ext2.h"
#include "xip.h"

static inline int
__inode_direct_access(struct inode *inode, sector_t block,
		      void **kaddr, unsigned long *pfn)
{
	struct block_device *bdev = inode->i_sb->s_bdev;
	const struct block_device_operations *ops = bdev->bd_disk->fops;
	sector_t sector;

	sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */

	BUG_ON(!ops->direct_access);
	return ops->direct_access(bdev, sector, kaddr, pfn);
}

static inline int
__ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
		   sector_t *result)
{
	struct buffer_head tmp;
	int rc;

	memset(&tmp, 0, sizeof(struct buffer_head));
	tmp.b_size = 1 << inode->i_blkbits;
	rc = ext2_get_block(inode, pgoff, &tmp, create);
	*result = tmp.b_blocknr;

	/* did we get a sparse block (hole in the file)? */
	if (!tmp.b_blocknr && !rc) {
		BUG_ON(create);
		rc = -ENODATA;
	}

	return rc;
}

int
ext2_clear_xip_target(struct inode *inode, sector_t block)
{
	void *kaddr;
	unsigned long pfn;
	int rc;

	rc = __inode_direct_access(inode, block, &kaddr, &pfn);
	if (!rc)
		clear_page(kaddr);
	return rc;
}

void ext2_xip_verify_sb(struct super_block *sb)
{
	struct ext2_sb_info *sbi = EXT2_SB(sb);

	if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
	    !sb->s_bdev->bd_disk->fops->direct_access) {
		sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
		ext2_msg(sb, KERN_WARNING,
			     "warning: ignoring xip option - "
			     "not supported by bdev");
	}
}

int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
				void **kmem, unsigned long *pfn)
{
	int rc;
	sector_t block;

	/* first, retrieve the sector number */
	rc = __ext2_get_block(mapping->host, pgoff, create, &block);
	if (rc)
		return rc;

	/* retrieve address of the target data */
	rc = __inode_direct_access(mapping->host, block, kmem, pfn);
	return rc;
}
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