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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
compr.c 
/*
 * fs/logfs/compr.c	- compression routines
 *
 * As should be obvious for Linux kernel code, license is GPLv2
 *
 * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
 */
#include "logfs.h"
#include <linux/vmalloc.h>
#include <linux/zlib.h>

#define COMPR_LEVEL 3

static DEFINE_MUTEX(compr_mutex);
static struct z_stream_s stream;

int logfs_compress(void *in, void *out, size_t inlen, size_t outlen)
{
	int err, ret;

	ret = -EIO;
	mutex_lock(&compr_mutex);
	err = zlib_deflateInit(&stream, COMPR_LEVEL);
	if (err != Z_OK)
		goto error;

	stream.next_in = in;
	stream.avail_in = inlen;
	stream.total_in = 0;
	stream.next_out = out;
	stream.avail_out = outlen;
	stream.total_out = 0;

	err = zlib_deflate(&stream, Z_FINISH);
	if (err != Z_STREAM_END)
		goto error;

	err = zlib_deflateEnd(&stream);
	if (err != Z_OK)
		goto error;

	if (stream.total_out >= stream.total_in)
		goto error;

	ret = stream.total_out;
error:
	mutex_unlock(&compr_mutex);
	return ret;
}

int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen)
{
	int err, ret;

	ret = -EIO;
	mutex_lock(&compr_mutex);
	err = zlib_inflateInit(&stream);
	if (err != Z_OK)
		goto error;

	stream.next_in = in;
	stream.avail_in = inlen;
	stream.total_in = 0;
	stream.next_out = out;
	stream.avail_out = outlen;
	stream.total_out = 0;

	err = zlib_inflate(&stream, Z_FINISH);
	if (err != Z_STREAM_END)
		goto error;

	err = zlib_inflateEnd(&stream);
	if (err != Z_OK)
		goto error;

	ret = 0;
error:
	mutex_unlock(&compr_mutex);
	return ret;
}

int __init logfs_compr_init(void)
{
	size_t size = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
			zlib_inflate_workspacesize());
	stream.workspace = vmalloc(size);
	if (!stream.workspace)
		return -ENOMEM;
	return 0;
}

void logfs_compr_exit(void)
{
	vfree(stream.workspace);
}
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