Hi,
        This patch has been created on top of the e2fsprogs-1.39-WIP and number
of other patches sent to list. But as it contains changes to recovery
part, should be able to apply safely on top of e2fsprogs-1.39-WIP.

Signed-off-by: Andreas Dilger <[EMAIL PROTECTED]>
Signed-off-by: Girish Shilamkar <[EMAIL PROTECTED]>

 diffstat patches/e2fsprogs-journal_chksum.patch
 e2fsck/recovery.c       |  124 ++++++++++-
 lib/ext2fs/Makefile.in  |    4 
 lib/ext2fs/crc32.c      |  522
++++++++++++++++++++++++++++++++++++++++++++++++
 lib/ext2fs/crc32.h      |   30 ++
 lib/ext2fs/crc32_user.h |   46 ++++
 lib/ext2fs/crc32defs.h  |   32 ++
 lib/ext2fs/crc32table.h |  135 ++++++++++++
 lib/ext2fs/kernel-jbd.h |   33 ++-
 8 files changed, 916 insertions(+), 10 deletions(-)


Index: e2fsprogs-1.39/lib/ext2fs/kernel-jbd.h
===================================================================
--- e2fsprogs-1.39.orig/lib/ext2fs/kernel-jbd.h
+++ e2fsprogs-1.39/lib/ext2fs/kernel-jbd.h
@@ -108,7 +108,29 @@ typedef struct journal_header_s
 	__u32		h_sequence;
 } journal_header_t;
 
+/*
+ * Checksum types.
+ */
+#define JFS_CRC32_CHKSUM   1
+#define JFS_MD5_CHKSUM     2
+#define JFS_SHA1_CHKSUM    3
+
+#define JFS_CRC32_CHKSUM_SIZE 4
 
+#define JFS_CHECKSUM_BYTES (32 / sizeof(__u32))
+/*
+ * Commit block header for storing transactional checksums:
+ */
+struct commit_header
+{
+	__u32		h_magic;
+	__u32		h_blocktype;
+	__u32		h_sequence;
+	unsigned char   h_chksum_type;
+	unsigned char   h_chksum_size;
+	unsigned char   h_padding[2];
+	__u32		h_chksum[JFS_CHECKSUM_BYTES];
+};
 /* 
  * The block tag: used to describe a single buffer in the journal 
  */
@@ -194,12 +216,17 @@ typedef struct journal_superblock_s
 	((j)->j_format_version >= 2 &&					\
 	 ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 
-#define JFS_FEATURE_INCOMPAT_REVOKE	0x00000001
+#define JFS_FEATURE_COMPAT_CHECKSUM    0x00000001
+
+#define JFS_FEATURE_INCOMPAT_REVOKE		0x00000001
+/*#define JFS_FEATURE_INCOMPAT_64BIT             0x00000002*/
+#define JFS_FEATURE_INCOMPAT_ASYNC_COMMIT	0x00000004
 
 /* Features known to this kernel version: */
-#define JFS_KNOWN_COMPAT_FEATURES	0
+#define JFS_KNOWN_COMPAT_FEATURES	JFS_FEATURE_COMPAT_CHECKSUM
 #define JFS_KNOWN_ROCOMPAT_FEATURES	0
-#define JFS_KNOWN_INCOMPAT_FEATURES	JFS_FEATURE_INCOMPAT_REVOKE
+#define JFS_KNOWN_INCOMPAT_FEATURES	(JFS_FEATURE_INCOMPAT_REVOKE| \
+					JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)
 
 #ifdef __KERNEL__
 
Index: e2fsprogs-1.39/lib/ext2fs/crc32.h
===================================================================
--- /dev/null
+++ e2fsprogs-1.39/lib/ext2fs/crc32.h
@@ -0,0 +1,30 @@
+/*
+ * crc32.h
+ * See crc32.c for license and changes
+ */
+#ifndef _LINUX_CRC32_H
+#define _LINUX_CRC32_H
+
+#include <linux/types.h>
+
+typedef unsigned int u32;
+typedef unsigned char u8;
+
+extern u32 crc32_le(u32 crc, unsigned char const *p, size_t len);
+extern u32 crc32_be(u32 crc, unsigned char const *p, size_t len);
+extern u32 bitreverse(u32 in);
+
+#define crc32(seed, data, length)  crc32_le(seed, (unsigned char const *)data, length)
+
+/*
+ * Helpers for hash table generation of ethernet nics:
+ *
+ * Ethernet sends the least significant bit of a byte first, thus crc32_le
+ * is used. The output of crc32_le is bit reversed [most significant bit
+ * is in bit nr 0], thus it must be reversed before use. Except for
+ * nics that bit swap the result internally...
+ */
+#define ether_crc(length, data)    bitreverse(crc32_le(~0, data, length))
+#define ether_crc_le(length, data) crc32_le(~0, data, length)
+
+#endif /* _LINUX_CRC32_H */
Index: e2fsprogs-1.39/lib/ext2fs/crc32.c
===================================================================
--- /dev/null
+++ e2fsprogs-1.39/lib/ext2fs/crc32.c
@@ -0,0 +1,522 @@
+/*
+ * Oct 15, 2000 Matt Domsch <[EMAIL PROTECTED]>
+ * Nicer crc32 functions/docs submitted by [EMAIL PROTECTED]  Thanks!
+ * Code was from the public domain, copyright abandoned.  Code was
+ * subsequently included in the kernel, thus was re-licensed under the
+ * GNU GPL v2.
+ *
+ * Oct 12, 2000 Matt Domsch <[EMAIL PROTECTED]>
+ * Same crc32 function was used in 5 other places in the kernel.
+ * I made one version, and deleted the others.
+ * There are various incantations of crc32().  Some use a seed of 0 or ~0.
+ * Some xor at the end with ~0.  The generic crc32() function takes
+ * seed as an argument, and doesn't xor at the end.  Then individual
+ * users can do whatever they need.
+ *   drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0.
+ *   fs/jffs2 uses seed 0, doesn't xor with ~0.
+ *   fs/partitions/efi.c uses seed ~0, xor's with ~0.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/compiler.h>
+#include <linux/init.h>
+#include <stdlib.h>
+#include "crc32_user.h"
+#include "crc32.h"
+#include "crc32defs.h"
+#if CRC_LE_BITS == 8
+#define tole(x) __constant_cpu_to_le32(x)
+#define tobe(x) __constant_cpu_to_be32(x)
+#else
+#define tole(x) (x)
+#define tobe(x) (x)
+#endif
+#include "crc32table.h"
+
+
+#if CRC_LE_BITS == 1
+/*
+ * In fact, the table-based code will work in this case, but it can be
+ * simplified by inlining the table in ?: form.
+ */
+
+/**
+ * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32
+ * @crc - seed value for computation.  ~0 for Ethernet, sometimes 0 for
+ *        other uses, or the previous crc32 value if computing incrementally.
+ * @p   - pointer to buffer over which CRC is run
+ * @len - length of buffer @p
+ * 
+ */
+u32  crc32_le(u32 crc, unsigned char const *p, size_t len)
+{
+	int i;
+	while (len--) {
+		crc ^= *p++;
+		for (i = 0; i < 8; i++)
+			crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
+	}
+	return crc;
+}
+#else				/* Table-based approach */
+
+/**
+ * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32
+ * @crc - seed value for computation.  ~0 for Ethernet, sometimes 0 for
+ *        other uses, or the previous crc32 value if computing incrementally.
+ * @p   - pointer to buffer over which CRC is run
+ * @len - length of buffer @p
+ * 
+ */
+u32  crc32_le(u32 crc, unsigned char const *p, size_t len)
+{
+# if CRC_LE_BITS == 8
+	const u32      *b =(u32 *)p;
+	const u32      *tab = crc32table_le;
+
+# ifdef __LITTLE_ENDIAN
+#  define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8)
+# else
+#  define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8)
+# endif
+
+	crc = __cpu_to_le32(crc);
+	/* Align it */
+	if(unlikely(((long)b)&3 && len)){
+		do {
+			u8 *p = (u8 *)b;
+			DO_CRC(*p++);
+			b = (void *)p;
+		} while ((--len) && ((long)b)&3 );
+	}
+	if(likely(len >= 4)){
+		/* load data 32 bits wide, xor data 32 bits wide. */
+		size_t save_len = len & 3;
+	        len = len >> 2;
+		--b; /* use pre increment below(*++b) for speed */
+		do {
+			crc ^= *++b;
+			DO_CRC(0);
+			DO_CRC(0);
+			DO_CRC(0);
+			DO_CRC(0);
+		} while (--len);
+		b++; /* point to next byte(s) */
+		len = save_len;
+	}
+	/* And the last few bytes */
+	if(len){
+		do {
+			u8 *p = (u8 *)b;
+			DO_CRC(*p++);
+			b = (void *)p;
+		} while (--len);
+	}
+
+	return __le32_to_cpu(crc);
+#undef ENDIAN_SHIFT
+#undef DO_CRC
+
+# elif CRC_LE_BITS == 4
+	while (len--) {
+		crc ^= *p++;
+		crc = (crc >> 4) ^ crc32table_le[crc & 15];
+		crc = (crc >> 4) ^ crc32table_le[crc & 15];
+	}
+	return crc;
+# elif CRC_LE_BITS == 2
+	while (len--) {
+		crc ^= *p++;
+		crc = (crc >> 2) ^ crc32table_le[crc & 3];
+		crc = (crc >> 2) ^ crc32table_le[crc & 3];
+		crc = (crc >> 2) ^ crc32table_le[crc & 3];
+		crc = (crc >> 2) ^ crc32table_le[crc & 3];
+	}
+	return crc;
+# endif
+}
+#endif
+
+#if CRC_BE_BITS == 1
+/*
+ * In fact, the table-based code will work in this case, but it can be
+ * simplified by inlining the table in ?: form.
+ */
+
+/**
+ * crc32_be() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32
+ * @crc - seed value for computation.  ~0 for Ethernet, sometimes 0 for
+ *        other uses, or the previous crc32 value if computing incrementally.
+ * @p   - pointer to buffer over which CRC is run
+ * @len - length of buffer @p
+ * 
+ */
+u32  crc32_be(u32 crc, unsigned char const *p, size_t len)
+{
+	int i;
+	while (len--) {
+		crc ^= *p++ << 24;
+		for (i = 0; i < 8; i++)
+			crc =
+			    (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE :
+					  0);
+	}
+	return crc;
+}
+
+#else				/* Table-based approach */
+/**
+ * crc32_be() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32
+ * @crc - seed value for computation.  ~0 for Ethernet, sometimes 0 for
+ *        other uses, or the previous crc32 value if computing incrementally.
+ * @p   - pointer to buffer over which CRC is run
+ * @len - length of buffer @p
+ * 
+ */
+u32  crc32_be(u32 crc, unsigned char const *p, size_t len)
+{
+# if CRC_BE_BITS == 8
+	const u32      *b =(u32 *)p;
+	const u32      *tab = crc32table_be;
+
+# ifdef __LITTLE_ENDIAN
+#  define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8)
+# else
+#  define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8)
+# endif
+
+	crc = __cpu_to_be32(crc);
+	/* Align it */
+	if(unlikely(((long)b)&3 && len)){
+		do {
+			u8 *p = (u8 *)b;
+			DO_CRC(*p++);
+			b = (u32 *)p;
+		} while ((--len) && ((long)b)&3 );
+	}
+	if(likely(len >= 4)){
+		/* load data 32 bits wide, xor data 32 bits wide. */
+		size_t save_len = len & 3;
+	        len = len >> 2;
+		--b; /* use pre increment below(*++b) for speed */
+		do {
+			crc ^= *++b;
+			DO_CRC(0);
+			DO_CRC(0);
+			DO_CRC(0);
+			DO_CRC(0);
+		} while (--len);
+		b++; /* point to next byte(s) */
+		len = save_len;
+	}
+	/* And the last few bytes */
+	if(len){
+		do {
+			u8 *p = (u8 *)b;
+			DO_CRC(*p++);
+			b = (void *)p;
+		} while (--len);
+	}
+	return __be32_to_cpu(crc);
+#undef ENDIAN_SHIFT
+#undef DO_CRC
+
+# elif CRC_BE_BITS == 4
+	while (len--) {
+		crc ^= *p++ << 24;
+		crc = (crc << 4) ^ crc32table_be[crc >> 28];
+		crc = (crc << 4) ^ crc32table_be[crc >> 28];
+	}
+	return crc;
+# elif CRC_BE_BITS == 2
+	while (len--) {
+		crc ^= *p++ << 24;
+		crc = (crc << 2) ^ crc32table_be[crc >> 30];
+		crc = (crc << 2) ^ crc32table_be[crc >> 30];
+		crc = (crc << 2) ^ crc32table_be[crc >> 30];
+		crc = (crc << 2) ^ crc32table_be[crc >> 30];
+	}
+	return crc;
+# endif
+}
+#endif
+
+u32 bitreverse(u32 x)
+{
+	x = (x >> 16) | (x << 16);
+	x = (x >> 8 & 0x00ff00ff) | (x << 8 & 0xff00ff00);
+	x = (x >> 4 & 0x0f0f0f0f) | (x << 4 & 0xf0f0f0f0);
+	x = (x >> 2 & 0x33333333) | (x << 2 & 0xcccccccc);
+	x = (x >> 1 & 0x55555555) | (x << 1 & 0xaaaaaaaa);
+	return x;
+}
+
+
+/*
+ * A brief CRC tutorial.
+ *
+ * A CRC is a long-division remainder.  You add the CRC to the message,
+ * and the whole thing (message+CRC) is a multiple of the given
+ * CRC polynomial.  To check the CRC, you can either check that the
+ * CRC matches the recomputed value, *or* you can check that the
+ * remainder computed on the message+CRC is 0.  This latter approach
+ * is used by a lot of hardware implementations, and is why so many
+ * protocols put the end-of-frame flag after the CRC.
+ *
+ * It's actually the same long division you learned in school, except that
+ * - We're working in binary, so the digits are only 0 and 1, and
+ * - When dividing polynomials, there are no carries.  Rather than add and
+ *   subtract, we just xor.  Thus, we tend to get a bit sloppy about
+ *   the difference between adding and subtracting.
+ *
+ * A 32-bit CRC polynomial is actually 33 bits long.  But since it's
+ * 33 bits long, bit 32 is always going to be set, so usually the CRC
+ * is written in hex with the most significant bit omitted.  (If you're
+ * familiar with the IEEE 754 floating-point format, it's the same idea.)
+ *
+ * Note that a CRC is computed over a string of *bits*, so you have
+ * to decide on the endianness of the bits within each byte.  To get
+ * the best error-detecting properties, this should correspond to the
+ * order they're actually sent.  For example, standard RS-232 serial is
+ * little-endian; the most significant bit (sometimes used for parity)
+ * is sent last.  And when appending a CRC word to a message, you should
+ * do it in the right order, matching the endianness.
+ *
+ * Just like with ordinary division, the remainder is always smaller than
+ * the divisor (the CRC polynomial) you're dividing by.  Each step of the
+ * division, you take one more digit (bit) of the dividend and append it
+ * to the current remainder.  Then you figure out the appropriate multiple
+ * of the divisor to subtract to being the remainder back into range.
+ * In binary, it's easy - it has to be either 0 or 1, and to make the
+ * XOR cancel, it's just a copy of bit 32 of the remainder.
+ *
+ * When computing a CRC, we don't care about the quotient, so we can
+ * throw the quotient bit away, but subtract the appropriate multiple of
+ * the polynomial from the remainder and we're back to where we started,
+ * ready to process the next bit.
+ *
+ * A big-endian CRC written this way would be coded like:
+ * for (i = 0; i < input_bits; i++) {
+ * 	multiple = remainder & 0x80000000 ? CRCPOLY : 0;
+ * 	remainder = (remainder << 1 | next_input_bit()) ^ multiple;
+ * }
+ * Notice how, to get at bit 32 of the shifted remainder, we look
+ * at bit 31 of the remainder *before* shifting it.
+ *
+ * But also notice how the next_input_bit() bits we're shifting into
+ * the remainder don't actually affect any decision-making until
+ * 32 bits later.  Thus, the first 32 cycles of this are pretty boring.
+ * Also, to add the CRC to a message, we need a 32-bit-long hole for it at
+ * the end, so we have to add 32 extra cycles shifting in zeros at the
+ * end of every message,
+ *
+ * So the standard trick is to rearrage merging in the next_input_bit()
+ * until the moment it's needed.  Then the first 32 cycles can be precomputed,
+ * and merging in the final 32 zero bits to make room for the CRC can be
+ * skipped entirely.
+ * This changes the code to:
+ * for (i = 0; i < input_bits; i++) {
+ *      remainder ^= next_input_bit() << 31;
+ * 	multiple = (remainder & 0x80000000) ? CRCPOLY : 0;
+ * 	remainder = (remainder << 1) ^ multiple;
+ * }
+ * With this optimization, the little-endian code is simpler:
+ * for (i = 0; i < input_bits; i++) {
+ *      remainder ^= next_input_bit();
+ * 	multiple = (remainder & 1) ? CRCPOLY : 0;
+ * 	remainder = (remainder >> 1) ^ multiple;
+ * }
+ *
+ * Note that the other details of endianness have been hidden in CRCPOLY
+ * (which must be bit-reversed) and next_input_bit().
+ *
+ * However, as long as next_input_bit is returning the bits in a sensible
+ * order, we can actually do the merging 8 or more bits at a time rather
+ * than one bit at a time:
+ * for (i = 0; i < input_bytes; i++) {
+ * 	remainder ^= next_input_byte() << 24;
+ * 	for (j = 0; j < 8; j++) {
+ * 		multiple = (remainder & 0x80000000) ? CRCPOLY : 0;
+ * 		remainder = (remainder << 1) ^ multiple;
+ * 	}
+ * }
+ * Or in little-endian:
+ * for (i = 0; i < input_bytes; i++) {
+ * 	remainder ^= next_input_byte();
+ * 	for (j = 0; j < 8; j++) {
+ * 		multiple = (remainder & 1) ? CRCPOLY : 0;
+ * 		remainder = (remainder << 1) ^ multiple;
+ * 	}
+ * }
+ * If the input is a multiple of 32 bits, you can even XOR in a 32-bit
+ * word at a time and increase the inner loop count to 32.
+ *
+ * You can also mix and match the two loop styles, for example doing the
+ * bulk of a message byte-at-a-time and adding bit-at-a-time processing
+ * for any fractional bytes at the end.
+ *
+ * The only remaining optimization is to the byte-at-a-time table method.
+ * Here, rather than just shifting one bit of the remainder to decide
+ * in the correct multiple to subtract, we can shift a byte at a time.
+ * This produces a 40-bit (rather than a 33-bit) intermediate remainder,
+ * but again the multiple of the polynomial to subtract depends only on
+ * the high bits, the high 8 bits in this case.  
+ *
+ * The multile we need in that case is the low 32 bits of a 40-bit
+ * value whose high 8 bits are given, and which is a multiple of the
+ * generator polynomial.  This is simply the CRC-32 of the given
+ * one-byte message.
+ *
+ * Two more details: normally, appending zero bits to a message which
+ * is already a multiple of a polynomial produces a larger multiple of that
+ * polynomial.  To enable a CRC to detect this condition, it's common to
+ * invert the CRC before appending it.  This makes the remainder of the
+ * message+crc come out not as zero, but some fixed non-zero value.
+ *
+ * The same problem applies to zero bits prepended to the message, and
+ * a similar solution is used.  Instead of starting with a remainder of
+ * 0, an initial remainder of all ones is used.  As long as you start
+ * the same way on decoding, it doesn't make a difference.
+ */
+
+#ifdef UNITTEST
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#if 0				/*Not used at present */
+static void
+buf_dump(char const *prefix, unsigned char const *buf, size_t len)
+{
+	fputs(prefix, stdout);
+	while (len--)
+		printf(" %02x", *buf++);
+	putchar('\n');
+
+}
+#endif
+
+static void bytereverse(unsigned char *buf, size_t len)
+{
+	while (len--) {
+		unsigned char x = *buf;
+		x = (x >> 4) | (x << 4);
+		x = (x >> 2 & 0x33) | (x << 2 & 0xcc);
+		x = (x >> 1 & 0x55) | (x << 1 & 0xaa);
+		*buf++ = x;
+	}
+}
+
+static void random_garbage(unsigned char *buf, size_t len)
+{
+	while (len--)
+		*buf++ = (unsigned char) random();
+}
+
+#if 0				/* Not used at present */
+static void store_le(u32 x, unsigned char *buf)
+{
+	buf[0] = (unsigned char) x;
+	buf[1] = (unsigned char) (x >> 8);
+	buf[2] = (unsigned char) (x >> 16);
+	buf[3] = (unsigned char) (x >> 24);
+}
+#endif
+
+static void store_be(u32 x, unsigned char *buf)
+{
+	buf[0] = (unsigned char) (x >> 24);
+	buf[1] = (unsigned char) (x >> 16);
+	buf[2] = (unsigned char) (x >> 8);
+	buf[3] = (unsigned char) x;
+}
+
+/*
+ * This checks that CRC(buf + CRC(buf)) = 0, and that
+ * CRC commutes with bit-reversal.  This has the side effect
+ * of bytewise bit-reversing the input buffer, and returns
+ * the CRC of the reversed buffer.
+ */
+static u32 test_step(u32 init, unsigned char *buf, size_t len)
+{
+	u32 crc1, crc2;
+	size_t i;
+
+	crc1 = crc32_be(init, buf, len);
+	store_be(crc1, buf + len);
+	crc2 = crc32_be(init, buf, len + 4);
+	if (crc2)
+		printf("\nCRC cancellation fail: 0x%08x should be 0\n",
+		       crc2);
+
+	for (i = 0; i <= len + 4; i++) {
+		crc2 = crc32_be(init, buf, i);
+		crc2 = crc32_be(crc2, buf + i, len + 4 - i);
+		if (crc2)
+			printf("\nCRC split fail: 0x%08x\n", crc2);
+	}
+
+	/* Now swap it around for the other test */
+
+	bytereverse(buf, len + 4);
+	init = bitreverse(init);
+	crc2 = bitreverse(crc1);
+	if (crc1 != bitreverse(crc2))
+		printf("\nBit reversal fail: 0x%08x -> %0x08x -> 0x%08x\n",
+		       crc1, crc2, bitreverse(crc2));
+	crc1 = crc32_le(init, buf, len);
+	if (crc1 != crc2)
+		printf("\nCRC endianness fail: 0x%08x != 0x%08x\n", crc1,
+		       crc2);
+	crc2 = crc32_le(init, buf, len + 4);
+	if (crc2)
+		printf("\nCRC cancellation fail: 0x%08x should be 0\n",
+		       crc2);
+
+	for (i = 0; i <= len + 4; i++) {
+		crc2 = crc32_le(init, buf, i);
+		crc2 = crc32_le(crc2, buf + i, len + 4 - i);
+		if (crc2)
+			printf("\nCRC split fail: 0x%08x\n", crc2);
+	}
+
+	return crc1;
+}
+
+#define SIZE 64
+#define INIT1 0
+#define INIT2 0
+
+int main(void)
+{
+	unsigned char buf1[SIZE + 4];
+	unsigned char buf2[SIZE + 4];
+	unsigned char buf3[SIZE + 4];
+	int i, j;
+	u32 crc1, crc2, crc3;
+
+	for (i = 0; i <= SIZE; i++) {
+		printf("\rTesting length %d...", i);
+		fflush(stdout);
+		random_garbage(buf1, i);
+		random_garbage(buf2, i);
+		for (j = 0; j < i; j++)
+			buf3[j] = buf1[j] ^ buf2[j];
+
+		crc1 = test_step(INIT1, buf1, i);
+		crc2 = test_step(INIT2, buf2, i);
+		/* Now check that CRC(buf1 ^ buf2) = CRC(buf1) ^ CRC(buf2) */
+		crc3 = test_step(INIT1 ^ INIT2, buf3, i);
+		if (crc3 != (crc1 ^ crc2))
+			printf("CRC XOR fail: 0x%08x != 0x%08x ^ 0x%08x\n",
+			       crc3, crc1, crc2);
+	}
+	printf("\nAll test complete.  No failures expected.\n");
+	return 0;
+}
+
+#endif				/* UNITTEST */
Index: e2fsprogs-1.39/lib/ext2fs/crc32defs.h
===================================================================
--- /dev/null
+++ e2fsprogs-1.39/lib/ext2fs/crc32defs.h
@@ -0,0 +1,32 @@
+/*
+ * There are multiple 16-bit CRC polynomials in common use, but this is
+ * *the* standard CRC-32 polynomial, first popularized by Ethernet.
+ * x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0
+ */
+#define CRCPOLY_LE 0xedb88320
+#define CRCPOLY_BE 0x04c11db7
+
+/* How many bits at a time to use.  Requires a table of 4<<CRC_xx_BITS bytes. */
+/* For less performance-sensitive, use 4 */
+#ifndef CRC_LE_BITS 
+# define CRC_LE_BITS 8
+#endif
+#ifndef CRC_BE_BITS
+# define CRC_BE_BITS 8
+#endif
+
+/*
+ * Little-endian CRC computation.  Used with serial bit streams sent
+ * lsbit-first.  Be sure to use cpu_to_le32() to append the computed CRC.
+ */
+#if CRC_LE_BITS > 8 || CRC_LE_BITS < 1 || CRC_LE_BITS & CRC_LE_BITS-1
+# error CRC_LE_BITS must be a power of 2 between 1 and 8
+#endif
+
+/*
+ * Big-endian CRC computation.  Used with serial bit streams sent
+ * msbit-first.  Be sure to use cpu_to_be32() to append the computed CRC.
+ */
+#if CRC_BE_BITS > 8 || CRC_BE_BITS < 1 || CRC_BE_BITS & CRC_BE_BITS-1
+# error CRC_BE_BITS must be a power of 2 between 1 and 8
+#endif
Index: e2fsprogs-1.39/lib/ext2fs/crc32table.h
===================================================================
--- /dev/null
+++ e2fsprogs-1.39/lib/ext2fs/crc32table.h
@@ -0,0 +1,135 @@
+/* this file is generated - do not edit */
+
+static const u32 crc32table_le[] = {
+tole(0x00000000L), tole(0x77073096L), tole(0xee0e612cL), tole(0x990951baL),
+tole(0x076dc419L), tole(0x706af48fL), tole(0xe963a535L), tole(0x9e6495a3L), 
+tole(0x0edb8832L), tole(0x79dcb8a4L), tole(0xe0d5e91eL), tole(0x97d2d988L), 
+tole(0x09b64c2bL), tole(0x7eb17cbdL), tole(0xe7b82d07L), tole(0x90bf1d91L), 
+tole(0x1db71064L), tole(0x6ab020f2L), tole(0xf3b97148L), tole(0x84be41deL), 
+tole(0x1adad47dL), tole(0x6ddde4ebL), tole(0xf4d4b551L), tole(0x83d385c7L), 
+tole(0x136c9856L), tole(0x646ba8c0L), tole(0xfd62f97aL), tole(0x8a65c9ecL), 
+tole(0x14015c4fL), tole(0x63066cd9L), tole(0xfa0f3d63L), tole(0x8d080df5L), 
+tole(0x3b6e20c8L), tole(0x4c69105eL), tole(0xd56041e4L), tole(0xa2677172L), 
+tole(0x3c03e4d1L), tole(0x4b04d447L), tole(0xd20d85fdL), tole(0xa50ab56bL), 
+tole(0x35b5a8faL), tole(0x42b2986cL), tole(0xdbbbc9d6L), tole(0xacbcf940L), 
+tole(0x32d86ce3L), tole(0x45df5c75L), tole(0xdcd60dcfL), tole(0xabd13d59L), 
+tole(0x26d930acL), tole(0x51de003aL), tole(0xc8d75180L), tole(0xbfd06116L), 
+tole(0x21b4f4b5L), tole(0x56b3c423L), tole(0xcfba9599L), tole(0xb8bda50fL), 
+tole(0x2802b89eL), tole(0x5f058808L), tole(0xc60cd9b2L), tole(0xb10be924L), 
+tole(0x2f6f7c87L), tole(0x58684c11L), tole(0xc1611dabL), tole(0xb6662d3dL), 
+tole(0x76dc4190L), tole(0x01db7106L), tole(0x98d220bcL), tole(0xefd5102aL), 
+tole(0x71b18589L), tole(0x06b6b51fL), tole(0x9fbfe4a5L), tole(0xe8b8d433L), 
+tole(0x7807c9a2L), tole(0x0f00f934L), tole(0x9609a88eL), tole(0xe10e9818L), 
+tole(0x7f6a0dbbL), tole(0x086d3d2dL), tole(0x91646c97L), tole(0xe6635c01L), 
+tole(0x6b6b51f4L), tole(0x1c6c6162L), tole(0x856530d8L), tole(0xf262004eL), 
+tole(0x6c0695edL), tole(0x1b01a57bL), tole(0x8208f4c1L), tole(0xf50fc457L), 
+tole(0x65b0d9c6L), tole(0x12b7e950L), tole(0x8bbeb8eaL), tole(0xfcb9887cL), 
+tole(0x62dd1ddfL), tole(0x15da2d49L), tole(0x8cd37cf3L), tole(0xfbd44c65L), 
+tole(0x4db26158L), tole(0x3ab551ceL), tole(0xa3bc0074L), tole(0xd4bb30e2L), 
+tole(0x4adfa541L), tole(0x3dd895d7L), tole(0xa4d1c46dL), tole(0xd3d6f4fbL), 
+tole(0x4369e96aL), tole(0x346ed9fcL), tole(0xad678846L), tole(0xda60b8d0L), 
+tole(0x44042d73L), tole(0x33031de5L), tole(0xaa0a4c5fL), tole(0xdd0d7cc9L), 
+tole(0x5005713cL), tole(0x270241aaL), tole(0xbe0b1010L), tole(0xc90c2086L), 
+tole(0x5768b525L), tole(0x206f85b3L), tole(0xb966d409L), tole(0xce61e49fL), 
+tole(0x5edef90eL), tole(0x29d9c998L), tole(0xb0d09822L), tole(0xc7d7a8b4L), 
+tole(0x59b33d17L), tole(0x2eb40d81L), tole(0xb7bd5c3bL), tole(0xc0ba6cadL), 
+tole(0xedb88320L), tole(0x9abfb3b6L), tole(0x03b6e20cL), tole(0x74b1d29aL), 
+tole(0xead54739L), tole(0x9dd277afL), tole(0x04db2615L), tole(0x73dc1683L), 
+tole(0xe3630b12L), tole(0x94643b84L), tole(0x0d6d6a3eL), tole(0x7a6a5aa8L), 
+tole(0xe40ecf0bL), tole(0x9309ff9dL), tole(0x0a00ae27L), tole(0x7d079eb1L), 
+tole(0xf00f9344L), tole(0x8708a3d2L), tole(0x1e01f268L), tole(0x6906c2feL), 
+tole(0xf762575dL), tole(0x806567cbL), tole(0x196c3671L), tole(0x6e6b06e7L), 
+tole(0xfed41b76L), tole(0x89d32be0L), tole(0x10da7a5aL), tole(0x67dd4accL), 
+tole(0xf9b9df6fL), tole(0x8ebeeff9L), tole(0x17b7be43L), tole(0x60b08ed5L), 
+tole(0xd6d6a3e8L), tole(0xa1d1937eL), tole(0x38d8c2c4L), tole(0x4fdff252L), 
+tole(0xd1bb67f1L), tole(0xa6bc5767L), tole(0x3fb506ddL), tole(0x48b2364bL), 
+tole(0xd80d2bdaL), tole(0xaf0a1b4cL), tole(0x36034af6L), tole(0x41047a60L), 
+tole(0xdf60efc3L), tole(0xa867df55L), tole(0x316e8eefL), tole(0x4669be79L), 
+tole(0xcb61b38cL), tole(0xbc66831aL), tole(0x256fd2a0L), tole(0x5268e236L), 
+tole(0xcc0c7795L), tole(0xbb0b4703L), tole(0x220216b9L), tole(0x5505262fL), 
+tole(0xc5ba3bbeL), tole(0xb2bd0b28L), tole(0x2bb45a92L), tole(0x5cb36a04L), 
+tole(0xc2d7ffa7L), tole(0xb5d0cf31L), tole(0x2cd99e8bL), tole(0x5bdeae1dL), 
+tole(0x9b64c2b0L), tole(0xec63f226L), tole(0x756aa39cL), tole(0x026d930aL), 
+tole(0x9c0906a9L), tole(0xeb0e363fL), tole(0x72076785L), tole(0x05005713L), 
+tole(0x95bf4a82L), tole(0xe2b87a14L), tole(0x7bb12baeL), tole(0x0cb61b38L), 
+tole(0x92d28e9bL), tole(0xe5d5be0dL), tole(0x7cdcefb7L), tole(0x0bdbdf21L), 
+tole(0x86d3d2d4L), tole(0xf1d4e242L), tole(0x68ddb3f8L), tole(0x1fda836eL), 
+tole(0x81be16cdL), tole(0xf6b9265bL), tole(0x6fb077e1L), tole(0x18b74777L), 
+tole(0x88085ae6L), tole(0xff0f6a70L), tole(0x66063bcaL), tole(0x11010b5cL), 
+tole(0x8f659effL), tole(0xf862ae69L), tole(0x616bffd3L), tole(0x166ccf45L), 
+tole(0xa00ae278L), tole(0xd70dd2eeL), tole(0x4e048354L), tole(0x3903b3c2L), 
+tole(0xa7672661L), tole(0xd06016f7L), tole(0x4969474dL), tole(0x3e6e77dbL), 
+tole(0xaed16a4aL), tole(0xd9d65adcL), tole(0x40df0b66L), tole(0x37d83bf0L), 
+tole(0xa9bcae53L), tole(0xdebb9ec5L), tole(0x47b2cf7fL), tole(0x30b5ffe9L), 
+tole(0xbdbdf21cL), tole(0xcabac28aL), tole(0x53b39330L), tole(0x24b4a3a6L), 
+tole(0xbad03605L), tole(0xcdd70693L), tole(0x54de5729L), tole(0x23d967bfL), 
+tole(0xb3667a2eL), tole(0xc4614ab8L), tole(0x5d681b02L), tole(0x2a6f2b94L), 
+tole(0xb40bbe37L), tole(0xc30c8ea1L), tole(0x5a05df1bL), tole(0x2d02ef8dL)
+};
+
+static const u32 crc32table_be[] = {
+tobe(0x00000000L), tobe(0x04c11db7L), tobe(0x09823b6eL), tobe(0x0d4326d9L),
+tobe(0x130476dcL), tobe(0x17c56b6bL), tobe(0x1a864db2L), tobe(0x1e475005L), 
+tobe(0x2608edb8L), tobe(0x22c9f00fL), tobe(0x2f8ad6d6L), tobe(0x2b4bcb61L), 
+tobe(0x350c9b64L), tobe(0x31cd86d3L), tobe(0x3c8ea00aL), tobe(0x384fbdbdL), 
+tobe(0x4c11db70L), tobe(0x48d0c6c7L), tobe(0x4593e01eL), tobe(0x4152fda9L), 
+tobe(0x5f15adacL), tobe(0x5bd4b01bL), tobe(0x569796c2L), tobe(0x52568b75L), 
+tobe(0x6a1936c8L), tobe(0x6ed82b7fL), tobe(0x639b0da6L), tobe(0x675a1011L), 
+tobe(0x791d4014L), tobe(0x7ddc5da3L), tobe(0x709f7b7aL), tobe(0x745e66cdL), 
+tobe(0x9823b6e0L), tobe(0x9ce2ab57L), tobe(0x91a18d8eL), tobe(0x95609039L), 
+tobe(0x8b27c03cL), tobe(0x8fe6dd8bL), tobe(0x82a5fb52L), tobe(0x8664e6e5L), 
+tobe(0xbe2b5b58L), tobe(0xbaea46efL), tobe(0xb7a96036L), tobe(0xb3687d81L), 
+tobe(0xad2f2d84L), tobe(0xa9ee3033L), tobe(0xa4ad16eaL), tobe(0xa06c0b5dL), 
+tobe(0xd4326d90L), tobe(0xd0f37027L), tobe(0xddb056feL), tobe(0xd9714b49L), 
+tobe(0xc7361b4cL), tobe(0xc3f706fbL), tobe(0xceb42022L), tobe(0xca753d95L), 
+tobe(0xf23a8028L), tobe(0xf6fb9d9fL), tobe(0xfbb8bb46L), tobe(0xff79a6f1L), 
+tobe(0xe13ef6f4L), tobe(0xe5ffeb43L), tobe(0xe8bccd9aL), tobe(0xec7dd02dL), 
+tobe(0x34867077L), tobe(0x30476dc0L), tobe(0x3d044b19L), tobe(0x39c556aeL), 
+tobe(0x278206abL), tobe(0x23431b1cL), tobe(0x2e003dc5L), tobe(0x2ac12072L), 
+tobe(0x128e9dcfL), tobe(0x164f8078L), tobe(0x1b0ca6a1L), tobe(0x1fcdbb16L), 
+tobe(0x018aeb13L), tobe(0x054bf6a4L), tobe(0x0808d07dL), tobe(0x0cc9cdcaL), 
+tobe(0x7897ab07L), tobe(0x7c56b6b0L), tobe(0x71159069L), tobe(0x75d48ddeL), 
+tobe(0x6b93dddbL), tobe(0x6f52c06cL), tobe(0x6211e6b5L), tobe(0x66d0fb02L), 
+tobe(0x5e9f46bfL), tobe(0x5a5e5b08L), tobe(0x571d7dd1L), tobe(0x53dc6066L), 
+tobe(0x4d9b3063L), tobe(0x495a2dd4L), tobe(0x44190b0dL), tobe(0x40d816baL), 
+tobe(0xaca5c697L), tobe(0xa864db20L), tobe(0xa527fdf9L), tobe(0xa1e6e04eL), 
+tobe(0xbfa1b04bL), tobe(0xbb60adfcL), tobe(0xb6238b25L), tobe(0xb2e29692L), 
+tobe(0x8aad2b2fL), tobe(0x8e6c3698L), tobe(0x832f1041L), tobe(0x87ee0df6L), 
+tobe(0x99a95df3L), tobe(0x9d684044L), tobe(0x902b669dL), tobe(0x94ea7b2aL), 
+tobe(0xe0b41de7L), tobe(0xe4750050L), tobe(0xe9362689L), tobe(0xedf73b3eL), 
+tobe(0xf3b06b3bL), tobe(0xf771768cL), tobe(0xfa325055L), tobe(0xfef34de2L), 
+tobe(0xc6bcf05fL), tobe(0xc27dede8L), tobe(0xcf3ecb31L), tobe(0xcbffd686L), 
+tobe(0xd5b88683L), tobe(0xd1799b34L), tobe(0xdc3abdedL), tobe(0xd8fba05aL), 
+tobe(0x690ce0eeL), tobe(0x6dcdfd59L), tobe(0x608edb80L), tobe(0x644fc637L), 
+tobe(0x7a089632L), tobe(0x7ec98b85L), tobe(0x738aad5cL), tobe(0x774bb0ebL), 
+tobe(0x4f040d56L), tobe(0x4bc510e1L), tobe(0x46863638L), tobe(0x42472b8fL), 
+tobe(0x5c007b8aL), tobe(0x58c1663dL), tobe(0x558240e4L), tobe(0x51435d53L), 
+tobe(0x251d3b9eL), tobe(0x21dc2629L), tobe(0x2c9f00f0L), tobe(0x285e1d47L), 
+tobe(0x36194d42L), tobe(0x32d850f5L), tobe(0x3f9b762cL), tobe(0x3b5a6b9bL), 
+tobe(0x0315d626L), tobe(0x07d4cb91L), tobe(0x0a97ed48L), tobe(0x0e56f0ffL), 
+tobe(0x1011a0faL), tobe(0x14d0bd4dL), tobe(0x19939b94L), tobe(0x1d528623L), 
+tobe(0xf12f560eL), tobe(0xf5ee4bb9L), tobe(0xf8ad6d60L), tobe(0xfc6c70d7L), 
+tobe(0xe22b20d2L), tobe(0xe6ea3d65L), tobe(0xeba91bbcL), tobe(0xef68060bL), 
+tobe(0xd727bbb6L), tobe(0xd3e6a601L), tobe(0xdea580d8L), tobe(0xda649d6fL), 
+tobe(0xc423cd6aL), tobe(0xc0e2d0ddL), tobe(0xcda1f604L), tobe(0xc960ebb3L), 
+tobe(0xbd3e8d7eL), tobe(0xb9ff90c9L), tobe(0xb4bcb610L), tobe(0xb07daba7L), 
+tobe(0xae3afba2L), tobe(0xaafbe615L), tobe(0xa7b8c0ccL), tobe(0xa379dd7bL), 
+tobe(0x9b3660c6L), tobe(0x9ff77d71L), tobe(0x92b45ba8L), tobe(0x9675461fL), 
+tobe(0x8832161aL), tobe(0x8cf30badL), tobe(0x81b02d74L), tobe(0x857130c3L), 
+tobe(0x5d8a9099L), tobe(0x594b8d2eL), tobe(0x5408abf7L), tobe(0x50c9b640L), 
+tobe(0x4e8ee645L), tobe(0x4a4ffbf2L), tobe(0x470cdd2bL), tobe(0x43cdc09cL), 
+tobe(0x7b827d21L), tobe(0x7f436096L), tobe(0x7200464fL), tobe(0x76c15bf8L), 
+tobe(0x68860bfdL), tobe(0x6c47164aL), tobe(0x61043093L), tobe(0x65c52d24L), 
+tobe(0x119b4be9L), tobe(0x155a565eL), tobe(0x18197087L), tobe(0x1cd86d30L), 
+tobe(0x029f3d35L), tobe(0x065e2082L), tobe(0x0b1d065bL), tobe(0x0fdc1becL), 
+tobe(0x3793a651L), tobe(0x3352bbe6L), tobe(0x3e119d3fL), tobe(0x3ad08088L), 
+tobe(0x2497d08dL), tobe(0x2056cd3aL), tobe(0x2d15ebe3L), tobe(0x29d4f654L), 
+tobe(0xc5a92679L), tobe(0xc1683bceL), tobe(0xcc2b1d17L), tobe(0xc8ea00a0L), 
+tobe(0xd6ad50a5L), tobe(0xd26c4d12L), tobe(0xdf2f6bcbL), tobe(0xdbee767cL), 
+tobe(0xe3a1cbc1L), tobe(0xe760d676L), tobe(0xea23f0afL), tobe(0xeee2ed18L), 
+tobe(0xf0a5bd1dL), tobe(0xf464a0aaL), tobe(0xf9278673L), tobe(0xfde69bc4L), 
+tobe(0x89b8fd09L), tobe(0x8d79e0beL), tobe(0x803ac667L), tobe(0x84fbdbd0L), 
+tobe(0x9abc8bd5L), tobe(0x9e7d9662L), tobe(0x933eb0bbL), tobe(0x97ffad0cL), 
+tobe(0xafb010b1L), tobe(0xab710d06L), tobe(0xa6322bdfL), tobe(0xa2f33668L), 
+tobe(0xbcb4666dL), tobe(0xb8757bdaL), tobe(0xb5365d03L), tobe(0xb1f740b4L)
+}; 
Index: e2fsprogs-1.39/lib/ext2fs/crc32_user.h
===================================================================
--- /dev/null
+++ e2fsprogs-1.39/lib/ext2fs/crc32_user.h
@@ -0,0 +1,46 @@
+/*
+ * Defines macros and types required by crc32 code undefined in user space.
+ */
+#ifndef _LINUX_CRC32_USER_H
+#define _LINUX_CRC32_USER_H 
+#include <linux/types.h>
+
+inline __u32 __swab32(__u32 val)
+{
+#ifdef EXT2FS_REQUIRE_486
+        __asm__("bswap %0" : "=r" (val) : "0" (val));
+#else
+        __asm__("xchgb %b0,%h0\n\t"     /* swap lower bytes     */
+                "rorl $16,%0\n\t"       /* swap words           */
+                "xchgb %b0,%h0"         /* swap higher bytes    */
+                :"=q" (val)
+                : "0" (val));
+#endif
+        return val;
+}
+
+#define ___constant_swab32(x) \
+        ((__u32)( \
+                (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
+                (((__u32)(x) & (__u32)0x0000ff00UL) <<  8) | \
+                (((__u32)(x) & (__u32)0x0000ff00UL) <<  8) | \
+                (((__u32)(x) & (__u32)0x00ff0000UL) >>  8) | \
+                (((__u32)(x) & (__u32)0xff000000UL) >> 24) ))
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define __le32_to_cpu(x) ((__u32)(x))
+#define __cpu_to_le32(x) ((__u32)(x))
+#define __be32_to_cpu(x) __swab32((x))
+#define __cpu_to_be32(x) __swab32((x))
+#define __constant_cpu_to_le32(x) ((__u32)(x))
+#define __constant_cpu_to_be32(x) (( __u32)___constant_swab32((x)))
+#else
+#define __le32_to_cpu(x) __swab32((x))
+#define __cpu_to_le32(x) __swab32((x))
+#define __be32_to_cpu(x) ((__u32)(x))
+#define __cpu_to_be32(x) ((__u32)(x))
+#define __constant_cpu_to_le32(x) ___constant_swab32((x))
+#define __constant_cpu_to_be32(x) ((__u32)(x))
+#endif
+
+#endif /* _LINUX_CRC32_USER_H */
Index: e2fsprogs-1.39/lib/ext2fs/Makefile.in
===================================================================
--- e2fsprogs-1.39.orig/lib/ext2fs/Makefile.in
+++ e2fsprogs-1.39/lib/ext2fs/Makefile.in
@@ -67,6 +67,7 @@ OBJS= $(DEBUGFS_LIB_OBJS) $(RESIZE_LIB_O
 	unlink.o \
 	valid_blk.o \
 	version.o \
+	crc32.o \
 	crc16.o \
 	csum.o
 
@@ -139,6 +140,7 @@ SRCS= ext2_err.c \
 	$(srcdir)/tst_types.c \
 	$(srcdir)/tst_iscan.c \
 	$(srcdir)/tst_csum.c \
+	$(srcdir)/crc32.c \
 	$(srcdir)/crc16.c \
 	$(srcdir)/csum.c
 
@@ -354,6 +356,8 @@ cmp_bitmaps.o: $(srcdir)/cmp_bitmaps.c $
  $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
  $(srcdir)/ext2_fs.h $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
  $(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/bitops.h
+crc32.o: $(srcdir)/crc32.c $(srcdir)/ext2_fs.h $(srcdir)/crc16.h \
+ $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h $(srcdir)/ext2_fs.h
 crc16.o: $(srcdir)/crc16.c $(srcdir)/ext2_fs.h $(srcdir)/crc16.h \
  $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h $(srcdir)/ext2_fs.h
 csum.o: $(srcdir)/csum.c $(srcdir)/ext2_fs.h \
Index: e2fsprogs-1.39/e2fsck/recovery.c
===================================================================
--- e2fsprogs-1.39.orig/e2fsck/recovery.c
+++ e2fsprogs-1.39/e2fsck/recovery.c
@@ -21,6 +21,7 @@
 #include <linux/jbd.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
+#include <linux/crc32.h>
 #endif
 
 /*
@@ -304,6 +305,36 @@ int journal_skip_recovery(journal_t *jou
 	return err;
 }
 
+/* cal_chksums calculates the checksums for the blocks described in the
+ * descriptor block.
+ */
+static int cal_chksums(journal_t *journal, struct buffer_head *bh,
+			unsigned long *next_log_block, __u32 *crc32_sum)
+{
+	int i, num_blks, err;
+	unsigned long io_block;
+	struct buffer_head *obh;
+
+	num_blks = count_tags(bh, journal->j_blocksize);
+	/* Calculate checksum of the descriptor block. */
+	*crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
+
+	for (i = 0; i < num_blks; i++) {
+		io_block = (*next_log_block)++;
+		wrap(journal, *next_log_block);
+		err = jread(&obh, journal, io_block);
+		if (err) {
+			printk (KERN_ERR "JBD: IO error %d recovering block "
+				"%ld in log\n", err, io_block);
+			return 1;
+		} else {
+			*crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
+				     obh->b_size);
+		}
+	}
+	return 0;
+}
+
 static int do_one_pass(journal_t *journal,
 			struct recovery_info *info, enum passtype pass)
 {
@@ -315,6 +346,7 @@ static int do_one_pass(journal_t *journa
 	struct buffer_head *	bh;
 	unsigned int		sequence;
 	int			blocktype;
+	__u32			crc32_sum = ~0; /* Transactional Checksums */
 	
 	/* Precompute the maximum metadata descriptors in a descriptor block */
 	int			MAX_BLOCKS_PER_DESC;
@@ -404,9 +436,24 @@ static int do_one_pass(journal_t *journa
 		switch(blocktype) {
 		case JFS_DESCRIPTOR_BLOCK:
 			/* If it is a valid descriptor block, replay it
-			 * in pass REPLAY; otherwise, just skip over the
-			 * blocks it describes. */
+			 * in pass REPLAY; if journal_checksums enabled, then
+			 * calculate checksums in PASS_SCAN, otherwise,
+			 * just skip over the blocks it describes. */
 			if (pass != PASS_REPLAY) {
+				if (pass == PASS_SCAN &&
+				    JFS_HAS_COMPAT_FEATURE(journal,
+					    JFS_FEATURE_COMPAT_CHECKSUM) &&
+				    !info->end_transaction) {
+					if (cal_chksums(journal, bh,
+							&next_log_block,
+							&crc32_sum)) {
+						brelse(bh);
+						break;
+					}
+					brelse(bh);
+					continue;
+				}
+
 				next_log_block +=
 					count_tags(bh, journal->j_blocksize);
 				wrap(journal, next_log_block);
@@ -501,9 +548,71 @@ static int do_one_pass(journal_t *journa
 			continue;
 
 		case JFS_COMMIT_BLOCK:
-			/* Found an expected commit block: not much to
-			 * do other than move on to the next sequence
+			/*     How to differentiate between interrupted commit
+			 *               and journal corruption ?
+			 *
+			 * {nth transaction}
+			 *        Checksum Verification Failed
+			 *			 |
+			 *		 ____________________
+			 *		|		     |
+			 * 	async_commit             sync_commit
+			 *     		|                    |
+			 *		| GO TO NEXT    "Journal Corruption"
+			 *		| TRANSACTION
+			 *		|
+			 * {(n+1)th transanction}
+		         *		|
+			 * 	 _______|______________
+			 * 	|	 	      |
+			 * Commit block found	Commit block not found
+		         *      |		      |
+		         * "Journal Corruption"       |
+		      	 *		 _____________|__________
+       			 *     		|	           	|
+		     	 *	nth trans corrupt	OR   nth trans
+		 	 *	and (n+1)th interrupted     interrupted	
+			 *	before commit block
+			 *      could reach the disk.
+			 *	(Cannot find the difference in above
+			 *	 mentioned conditions. Hence assume
+			 *	 "Interrupted Commit".)
+			 */
+
+			/* Found an expected commit block: if checksums
+			 * are present verify them in PASS_SCAN; else not
+			 * much to do other than move on to the next sequence
 			 * number. */
+			if (pass == PASS_SCAN &&
+			    JFS_HAS_COMPAT_FEATURE(journal,
+				    JFS_FEATURE_COMPAT_CHECKSUM)) {
+				struct commit_header *cbh =
+	  				(struct commit_header *)bh->b_data;
+
+				if (info->end_transaction) {
+					printk(KERN_ERR "JBD: Transaction %u "
+						"found to be corrupt.\n",
+						next_commit_ID - 1);
+					brelse(bh);
+					break;
+				}
+
+				if (crc32_sum != cbh->h_chksum[0]) {
+					info->end_transaction = next_commit_ID;
+
+					if (!JFS_HAS_COMPAT_FEATURE(journal,
+					    JFS_FEATURE_INCOMPAT_ASYNC_COMMIT))
+					{
+						printk(KERN_ERR
+						       "JBD: Transaction %u "
+       						       "found to be corrupt.\n",
+       						       next_commit_ID);
+						brelse(bh);
+						break;
+					}
+				}
+				crc32_sum = ~0;
+			}
 			brelse(bh);
 			next_commit_ID++;
 			continue;
@@ -539,9 +648,10 @@ static int do_one_pass(journal_t *journa
 	 * transaction marks the end of the valid log.
 	 */
 	
-	if (pass == PASS_SCAN)
-		info->end_transaction = next_commit_ID;
-	else {
+	if (pass == PASS_SCAN) {
+ 		if (!info->end_transaction)
+       		       info->end_transaction = next_commit_ID;
+	} else {
 		/* It's really bad news if different passes end up at
 		 * different places (but possible due to IO errors). */
 		if (info->end_transaction != next_commit_ID) {

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