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Revision 38e87880666091fe9c572a7a2ed2e771d97ca5aa authored by Chris Mason on 10 June 2011, 20:36:57 UTC, committed by Chris Mason on 10 June 2011, 20:36:57 UTC 
Btrfs: make sure to recheck for bitmaps in clusters
 
Josef recently changed the free extent cache to look in
the block group cluster for any bitmaps before trying to
add a new bitmap for the same offset.  This avoids BUG_ON()s due
covering duplicate ranges.

But it didn't go quite far enough.  A given free range might span
between one or more bitmaps or free space entries.  The code has
looping to cover this, but it doesn't check for clustered bitmaps
every time.

This shuffles our gotos to check for a bitmap in the cluster
for every new bitmap entry we try to add.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
1 parent 3473f3c
Raw File
sha1.c 
/*
 * SHA transform algorithm, originally taken from code written by
 * Peter Gutmann, and placed in the public domain.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/cryptohash.h>

/* The SHA f()-functions.  */

#define f1(x,y,z)   (z ^ (x & (y ^ z)))		/* x ? y : z */
#define f2(x,y,z)   (x ^ y ^ z)			/* XOR */
#define f3(x,y,z)   ((x & y) + (z & (x ^ y)))	/* majority */

/* The SHA Mysterious Constants */

#define K1  0x5A827999L			/* Rounds  0-19: sqrt(2) * 2^30 */
#define K2  0x6ED9EBA1L			/* Rounds 20-39: sqrt(3) * 2^30 */
#define K3  0x8F1BBCDCL			/* Rounds 40-59: sqrt(5) * 2^30 */
#define K4  0xCA62C1D6L			/* Rounds 60-79: sqrt(10) * 2^30 */

/**
 * sha_transform - single block SHA1 transform
 *
 * @digest: 160 bit digest to update
 * @data:   512 bits of data to hash
 * @W:      80 words of workspace (see note)
 *
 * This function generates a SHA1 digest for a single 512-bit block.
 * Be warned, it does not handle padding and message digest, do not
 * confuse it with the full FIPS 180-1 digest algorithm for variable
 * length messages.
 *
 * Note: If the hash is security sensitive, the caller should be sure
 * to clear the workspace. This is left to the caller to avoid
 * unnecessary clears between chained hashing operations.
 */
void sha_transform(__u32 *digest, const char *in, __u32 *W)
{
	__u32 a, b, c, d, e, t, i;

	for (i = 0; i < 16; i++)
		W[i] = be32_to_cpu(((const __be32 *)in)[i]);

	for (i = 0; i < 64; i++)
		W[i+16] = rol32(W[i+13] ^ W[i+8] ^ W[i+2] ^ W[i], 1);

	a = digest[0];
	b = digest[1];
	c = digest[2];
	d = digest[3];
	e = digest[4];

	for (i = 0; i < 20; i++) {
		t = f1(b, c, d) + K1 + rol32(a, 5) + e + W[i];
		e = d; d = c; c = rol32(b, 30); b = a; a = t;
	}

	for (; i < 40; i ++) {
		t = f2(b, c, d) + K2 + rol32(a, 5) + e + W[i];
		e = d; d = c; c = rol32(b, 30); b = a; a = t;
	}

	for (; i < 60; i ++) {
		t = f3(b, c, d) + K3 + rol32(a, 5) + e + W[i];
		e = d; d = c; c = rol32(b, 30); b = a; a = t;
	}

	for (; i < 80; i ++) {
		t = f2(b, c, d) + K4 + rol32(a, 5) + e + W[i];
		e = d; d = c; c = rol32(b, 30); b = a; a = t;
	}

	digest[0] += a;
	digest[1] += b;
	digest[2] += c;
	digest[3] += d;
	digest[4] += e;
}
EXPORT_SYMBOL(sha_transform);

/**
 * sha_init - initialize the vectors for a SHA1 digest
 * @buf: vector to initialize
 */
void sha_init(__u32 *buf)
{
	buf[0] = 0x67452301;
	buf[1] = 0xefcdab89;
	buf[2] = 0x98badcfe;
	buf[3] = 0x10325476;
	buf[4] = 0xc3d2e1f0;
}
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