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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
crc-t10dif.c 
/*
 * T10 Data Integrity Field CRC16 calculation
 *
 * Copyright (c) 2007 Oracle Corporation.  All rights reserved.
 * Written by Martin K. Petersen <martin.petersen@oracle.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2. See the file COPYING for more details.
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/crc-t10dif.h>
#include <linux/err.h>
#include <linux/init.h>
#include <crypto/hash.h>
#include <linux/static_key.h>

static struct crypto_shash *crct10dif_tfm;
static struct static_key crct10dif_fallback __read_mostly;

__u16 crc_t10dif(const unsigned char *buffer, size_t len)
{
	struct {
		struct shash_desc shash;
		char ctx[2];
	} desc;
	int err;

	if (static_key_false(&crct10dif_fallback))
		return crc_t10dif_generic(0, buffer, len);

	desc.shash.tfm = crct10dif_tfm;
	desc.shash.flags = 0;
	*(__u16 *)desc.ctx = 0;

	err = crypto_shash_update(&desc.shash, buffer, len);
	BUG_ON(err);

	return *(__u16 *)desc.ctx;
}
EXPORT_SYMBOL(crc_t10dif);

static int __init crc_t10dif_mod_init(void)
{
	crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
	if (IS_ERR(crct10dif_tfm)) {
		static_key_slow_inc(&crct10dif_fallback);
		crct10dif_tfm = NULL;
	}
	return 0;
}

static void __exit crc_t10dif_mod_fini(void)
{
	crypto_free_shash(crct10dif_tfm);
}

module_init(crc_t10dif_mod_init);
module_exit(crc_t10dif_mod_fini);

MODULE_DESCRIPTION("T10 DIF CRC calculation");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: crct10dif");
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