From a4f6739fcb935ba16dfd0857732109868cddebce Mon Sep 17 00:00:00 2001
From: girish <girish>
Date: Mon, 20 Aug 2007 10:25:22 +0000
Subject: [PATCH] Add kernel part of Journal Checksum feature. b=10657
 i=adilger i=kalpak

---
 lustre/ChangeLog                              |  12 +
 .../jbd-journal-chksum-2.6-sles10.patch       | 617 ++++++++++++++++++
 .../jbd-journal-chksum-2.6.18-vanilla.patch   | 616 +++++++++++++++++
 lustre/kernel_patches/series/2.6-rhel5.series |   1 +
 .../kernel_patches/series/2.6-sles10.series   |   1 +
 .../series/2.6.18-vanilla.series              |   1 +
 6 files changed, 1248 insertions(+)
 create mode 100644 lustre/kernel_patches/patches/jbd-journal-chksum-2.6-sles10.patch
 create mode 100644 lustre/kernel_patches/patches/jbd-journal-chksum-2.6.18-vanilla.patch

diff --git a/lustre/ChangeLog b/lustre/ChangeLog
index e14c210bb7..4d0eaaa7a8 100644
--- a/lustre/ChangeLog
+++ b/lustre/ChangeLog
@@ -46,6 +46,18 @@ Bugzilla   : 11248
 Description: merge and cleanup kernel patches.
 Details    : Remove mnt_lustre_list in vfs_intent-2.6-rhel4.patch.
 
+Severity   : normal
+Bugzilla   : 10657
+Description: Add journal checksum support.(Kernel part)
+Details    : The journal checksum feature adds two new flags i.e 
+             JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT and 
+	     JBD2_FEATURE_COMPAT_CHECKSUM. JBD2_FEATURE_CHECKSUM flag 
+	     indicates that the commit block contains the checksum for
+	     the blocks described by the descriptor blocks. Now commit
+	     record can be sent to disk without waiting for descriptor
+	     blocks to be written to disk. This behavior is controlled
+	     using JBD2_FEATURE_ASYNC_COMMIT flag.
+
 --------------------------------------------------------------------------------
 
 2007-08-27         Cluster File Systems, Inc. <info@clusterfs.com>
diff --git a/lustre/kernel_patches/patches/jbd-journal-chksum-2.6-sles10.patch b/lustre/kernel_patches/patches/jbd-journal-chksum-2.6-sles10.patch
new file mode 100644
index 0000000000..f55ca27487
--- /dev/null
+++ b/lustre/kernel_patches/patches/jbd-journal-chksum-2.6-sles10.patch
@@ -0,0 +1,617 @@
+Index: linux-2.6.16.46-0.14/fs/jbd/commit.c
+===================================================================
+--- linux-2.6.16.46-0.14.orig/fs/jbd/commit.c
++++ linux-2.6.16.46-0.14/fs/jbd/commit.c
+@@ -22,6 +22,7 @@
+ #include <linux/pagemap.h>
+ #include <linux/smp_lock.h>
+ #include <linux/jiffies.h>
++#include <linux/crc32.h>
+ 
+ /*
+  * Default IO end handler for temporary BJ_IO buffer_heads.
+@@ -94,19 +95,23 @@ static int inverted_lock(journal_t *jour
+ 	return 1;
+ }
+ 
+-/* Done it all: now write the commit record.  We should have
++/*
++ * Done it all: now submit the commit record.  We should have
+  * cleaned up our previous buffers by now, so if we are in abort
+  * mode we can now just skip the rest of the journal write
+  * entirely.
+  *
+  * Returns 1 if the journal needs to be aborted or 0 on success
+  */
+-static int journal_write_commit_record(journal_t *journal,
+-					transaction_t *commit_transaction)
++static int journal_submit_commit_record(journal_t *journal,
++					transaction_t *commit_transaction,
++					struct buffer_head **cbh,
++					__u32 crc32_sum)
+ {
+ 	struct journal_head *descriptor;
++	struct commit_header *tmp;
+ 	struct buffer_head *bh;
+-	int i, ret;
++	int ret;
+ 	int barrier_done = 0;
+ 
+ 	if (is_journal_aborted(journal))
+@@ -118,21 +123,34 @@ static int journal_write_commit_record(j
+ 
+ 	bh = jh2bh(descriptor);
+ 
+-	/* AKPM: buglet - add `i' to tmp! */
+-	for (i = 0; i < bh->b_size; i += 512) {
+-		journal_header_t *tmp = (journal_header_t*)bh->b_data;
+-		tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
+-		tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
+-		tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
++	tmp = (struct commit_header *)bh->b_data;
++	tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
++	tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
++	tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
++ 		 		
++	if (JFS_HAS_COMPAT_FEATURE(journal,
++				JFS_FEATURE_COMPAT_CHECKSUM)) {
++		tmp->h_chksum_type 	= JFS_CRC32_CHKSUM;
++		tmp->h_chksum_size 	= JFS_CRC32_CHKSUM_SIZE;
++		tmp->h_chksum[0] 	= cpu_to_be32(crc32_sum);
+ 	}
+ 
+-	JBUFFER_TRACE(descriptor, "write commit block");
++	JBUFFER_TRACE(descriptor, "submit commit block");
++	lock_buffer(bh);
++
+ 	set_buffer_dirty(bh);
+-	if (journal->j_flags & JFS_BARRIER) {
++	set_buffer_uptodate(bh);
++	bh->b_end_io = journal_end_buffer_io_sync;
++
++	if (journal->j_flags & JFS_BARRIER &&
++		!JFS_HAS_COMPAT_FEATURE(journal,
++					 JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
++
+ 		set_buffer_ordered(bh);
+ 		barrier_done = 1;
+ 	}
+-	ret = sync_dirty_buffer(bh);
++	ret = submit_bh(WRITE, bh);
++
+ 	/* is it possible for another commit to fail at roughly
+ 	 * the same time as this one?  If so, we don't want to
+ 	 * trust the barrier flag in the super, but instead want
+@@ -153,15 +171,74 @@ static int journal_write_commit_record(j
+ 		clear_buffer_ordered(bh);
+ 		set_buffer_uptodate(bh);
+ 		set_buffer_dirty(bh);
+-		ret = sync_dirty_buffer(bh);
++		ret = submit_bh(WRITE, bh);
+ 	}
+-	put_bh(bh);		/* One for getblk() */
+-	journal_put_journal_head(descriptor);
++	*cbh = bh;
++	return ret;
++}
+ 
+-	return (ret == -EIO);
++/*
++ * This function along with journal_submit_commit_record
++ * allows to write the commit record asynchronously.
++ */
++static int journal_wait_on_commit_record(struct buffer_head *bh)
++{
++	int ret = 0;
++
++	clear_buffer_dirty(bh);
++	wait_on_buffer(bh);
++	
++	if (unlikely(!buffer_uptodate(bh)))
++		ret = -EIO;
++	put_bh(bh);            /* One for getblk() */
++	journal_put_journal_head(bh2jh(bh));
++	
++	return ret;
+ }
+ 
+ /*
++ * Wait for all submitted IO to complete.
++ */
++static int journal_wait_on_locked_list(journal_t *journal,
++				       transaction_t *commit_transaction)
++{
++	int ret = 0;
++	struct journal_head *jh;
++
++	while (commit_transaction->t_locked_list) {
++		struct buffer_head *bh;
++
++		jh = commit_transaction->t_locked_list->b_tprev;
++		bh = jh2bh(jh);
++		get_bh(bh);
++		if (buffer_locked(bh)) {
++			spin_unlock(&journal->j_list_lock);
++			wait_on_buffer(bh);
++			if (unlikely(!buffer_uptodate(bh)))
++				ret = -EIO;
++			spin_lock(&journal->j_list_lock);
++		}
++		if (!inverted_lock(journal, bh)) {
++			put_bh(bh);
++			spin_lock(&journal->j_list_lock);
++			continue;
++		}
++		if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
++			__journal_unfile_buffer(jh);
++			jbd_unlock_bh_state(bh);
++			journal_remove_journal_head(bh);
++			put_bh(bh);
++		} else {
++			jbd_unlock_bh_state(bh);
++		}
++		put_bh(bh);
++		cond_resched_lock(&journal->j_list_lock);
++	}
++	return ret;
++}
++
++
++/*
+  * journal_commit_transaction
+  *
+  * The primary function for committing a transaction to the log.  This
+@@ -184,6 +261,8 @@ void journal_commit_transaction(journal_
+ 	int first_tag = 0;
+ 	int tag_flag;
+ 	int i;
++	struct buffer_head *cbh = NULL; /* For transactional checksums */
++	__u32 crc32_sum = ~0;
+ 
+ 	/*
+ 	 * First job: lock down the current transaction and wait for
+@@ -395,37 +474,14 @@ write_out_data:
+ 	}
+ 
+ 	/*
+-	 * Wait for all previously submitted IO to complete.
++	 * Wait for all previously submitted IO to complete if commit
++	 * record is to be written synchronously.
+ 	 */
+-	while (commit_transaction->t_locked_list) {
+-		struct buffer_head *bh;
++	if (!JFS_HAS_INCOMPAT_FEATURE(journal,
++		JFS_FEATURE_INCOMPAT_ASYNC_COMMIT))
++		err = journal_wait_on_locked_list(journal,
++						  commit_transaction);
+ 
+-		jh = commit_transaction->t_locked_list->b_tprev;
+-		bh = jh2bh(jh);
+-		get_bh(bh);
+-		if (buffer_locked(bh)) {
+-			spin_unlock(&journal->j_list_lock);
+-			wait_on_buffer(bh);
+-			if (unlikely(!buffer_uptodate(bh)))
+-				err = -EIO;
+-			spin_lock(&journal->j_list_lock);
+-		}
+-		if (!inverted_lock(journal, bh)) {
+-			put_bh(bh);
+-			spin_lock(&journal->j_list_lock);
+-			continue;
+-		}
+-		if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
+-			__journal_unfile_buffer(jh);
+-			jbd_unlock_bh_state(bh);
+-			journal_remove_journal_head(bh);
+-			put_bh(bh);
+-		} else {
+-			jbd_unlock_bh_state(bh);
+-		}
+-		put_bh(bh);
+-		cond_resched_lock(&journal->j_list_lock);
+-	}
+ 	spin_unlock(&journal->j_list_lock);
+ 
+ 	if (err)
+@@ -598,6 +654,16 @@ write_out_data:
+ start_journal_io:
+ 			for (i = 0; i < bufs; i++) {
+ 				struct buffer_head *bh = wbuf[i];
++				/*
++				 * Compute checksum.
++				 */
++				if (JFS_HAS_COMPAT_FEATURE(journal,
++					JFS_FEATURE_COMPAT_CHECKSUM)) {
++					crc32_sum = crc32_be(crc32_sum,
++							(void *)bh->b_data,
++							bh->b_size);
++				}
++
+ 				lock_buffer(bh);
+ 				clear_buffer_dirty(bh);
+ 				set_buffer_uptodate(bh);
+@@ -614,6 +680,23 @@ start_journal_io:
+ 		}
+ 	}
+ 
++	/* Done it all: now write the commit record asynchronously. */
++
++	if (JFS_HAS_INCOMPAT_FEATURE(journal,
++		JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
++		err = journal_submit_commit_record(journal, commit_transaction,
++						 &cbh, crc32_sum);
++		if (err)
++			__journal_abort_hard(journal);
++
++		spin_lock(&journal->j_list_lock);
++		err = journal_wait_on_locked_list(journal,
++						commit_transaction);
++		spin_unlock(&journal->j_list_lock);
++		if (err)
++			__journal_abort_hard(journal);
++	}
++
+ 	/* Lo and behold: we have just managed to send a transaction to
+            the log.  Before we can commit it, wait for the IO so far to
+            complete.  Control buffers being written are on the
+@@ -712,9 +795,15 @@ wait_for_iobuf:
+ 	}
+ 
+ 	jbd_debug(3, "JBD: commit phase 6\n");
+-
+-	if (journal_write_commit_record(journal, commit_transaction))
+-		err = -EIO;
++		
++	if (!JFS_HAS_INCOMPAT_FEATURE(journal,
++		JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
++		err = journal_submit_commit_record(journal, commit_transaction,
++						&cbh, crc32_sum);
++		if (err)
++			__journal_abort_hard(journal);
++	}
++	err = journal_wait_on_commit_record(cbh);
+ 
+ 	if (err)
+ 		__journal_abort_hard(journal);
+Index: linux-2.6.16.46-0.14/include/linux/jbd.h
+===================================================================
+--- linux-2.6.16.46-0.14.orig/include/linux/jbd.h
++++ linux-2.6.16.46-0.14/include/linux/jbd.h
+@@ -142,6 +142,29 @@ typedef struct journal_header_s
+ 	__be32		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
++{
++	__be32		h_magic;
++	__be32          h_blocktype;
++	__be32          h_sequence;
++	unsigned char   h_chksum_type;
++	unsigned char   h_chksum_size;
++	unsigned char 	h_padding[2];
++	__be32 		h_chksum[JFS_CHECKSUM_BYTES];
++};
+ 
+ /* 
+  * The block tag: used to describe a single buffer in the journal 
+@@ -228,12 +251,16 @@ 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_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__
+ 
+@@ -1041,6 +1068,8 @@ extern int	   journal_check_available_fe
+ 		   (journal_t *, unsigned long, unsigned long, unsigned long);
+ extern int	   journal_set_features 
+ 		   (journal_t *, unsigned long, unsigned long, unsigned long);
++extern int	   journal_clear_features
++		   (journal_t *, unsigned long, unsigned long, unsigned long);
+ extern int	   journal_create     (journal_t *);
+ extern int	   journal_load       (journal_t *journal);
+ extern void	   journal_destroy    (journal_t *);
+Index: linux-2.6.16.46-0.14/fs/jbd/recovery.c
+===================================================================
+--- linux-2.6.16.46-0.14.orig/fs/jbd/recovery.c
++++ linux-2.6.16.46-0.14/fs/jbd/recovery.c
+@@ -21,6 +21,7 @@
+ #include <linux/jbd.h>
+ #include <linux/errno.h>
+ #include <linux/slab.h>
++#include <linux/crc32.h>
+ #endif
+ 
+ /*
+@@ -307,6 +308,37 @@ int journal_skip_recovery(journal_t *jou
+ 	return err;
+ }
+ 
++/*
++ * calc_chksums calculates the checksums for the blocks described in the
++ * descriptor block.
++ */
++static int calc_chksums(journal_t *journal, struct buffer_head *bh,
++		       unsigned long *next_log_block, __u32 *crc32_sum)
++{
++	int i, num_blks, err;
++	unsigned 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 "
++				"%u 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)
+ {
+@@ -318,6 +350,7 @@ 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;
+@@ -409,9 +442,24 @@ 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 (calc_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);
+@@ -506,9 +554,97 @@ 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)) {
++				int chksum_err, chksum_seen;
++				struct commit_header *cbh =
++					(struct commit_header *)bh->b_data;
++				unsigned found_chksum =
++						be32_to_cpu(cbh->h_chksum[0]);
++
++				chksum_err = chksum_seen = 0;
++
++				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 == found_chksum &&
++				    cbh->h_chksum_type == JFS_CRC32_CHKSUM &&
++				    cbh->h_chksum_size ==
++						JFS_CRC32_CHKSUM_SIZE) {
++				       chksum_seen = 1;
++				} else if (!(cbh->h_chksum_type == 0 &&
++					     cbh->h_chksum_size == 0 &&
++					     found_chksum == 0 &&
++					     !chksum_seen)) {
++				/*
++				 * If fs is mounted using an old kernel and then
++				 * kernel with journal_chksum is used then we
++				 * get a situation where the journal flag has
++				 * checksum flag set but checksums are not
++				 * present i.e chksum = 0, in the individual
++				 * commit blocks.
++				 * Hence to avoid checksum failures, in this
++				 * situation, this extra check is added.
++				 */
++						chksum_err = 1;
++				}
++
++				if (chksum_err) {
++					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;
+@@ -543,9 +679,10 @@ 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) {
+Index: linux-2.6.16.46-0.14/fs/jbd/journal.c
+===================================================================
+--- linux-2.6.16.46-0.14.orig/fs/jbd/journal.c
++++ linux-2.6.16.46-0.14/fs/jbd/journal.c
+@@ -64,6 +64,7 @@ EXPORT_SYMBOL(journal_update_format);
+ EXPORT_SYMBOL(journal_check_used_features);
+ EXPORT_SYMBOL(journal_check_available_features);
+ EXPORT_SYMBOL(journal_set_features);
++EXPORT_SYMBOL(journal_clear_features);
+ EXPORT_SYMBOL(journal_create);
+ EXPORT_SYMBOL(journal_load);
+ EXPORT_SYMBOL(journal_destroy);
+@@ -1565,6 +1566,33 @@ int journal_set_features (journal_t *jou
+ 	return 1;
+ }
+ 
++/**
++ * int journal_clear_features () - Clear a given journal feature in the superblock
++ * @journal: Journal to act on.
++ * @compat: bitmask of compatible features
++ * @ro: bitmask of features that force read-only mount
++ * @incompat: bitmask of incompatible features
++ *
++ * Clear a given journal feature as present on the
++ * superblock.  Returns true if the requested features could be reset.
++ *
++ */
++int journal_clear_features (journal_t *journal, unsigned long compat,
++			  unsigned long ro, unsigned long incompat)
++{
++	journal_superblock_t *sb;
++
++	jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
++		  compat, ro, incompat);
++
++	sb = journal->j_superblock;
++
++	sb->s_feature_compat    &= ~cpu_to_be32(compat);
++	sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
++	sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
++
++	return 1;
++}
+ 
+ /**
+  * int journal_update_format () - Update on-disk journal structure.
+Index: linux-2.6.16.46-0.14/fs/Kconfig
+===================================================================
+--- linux-2.6.16.46-0.14.orig/fs/Kconfig
++++ linux-2.6.16.46-0.14/fs/Kconfig
+@@ -140,6 +140,7 @@ config EXT3_FS_SECURITY
+ 
+ config JBD
+ 	tristate
++	select CRC32
+ 	help
+ 	  This is a generic journaling layer for block devices.  It is
+ 	  currently used by the ext3 and OCFS2 file systems, but it could
+Index: linux-2.6.16.46-0.14/Documentation/filesystems/ext3.txt
+===================================================================
+--- linux-2.6.16.46-0.14.orig/Documentation/filesystems/ext3.txt
++++ linux-2.6.16.46-0.14/Documentation/filesystems/ext3.txt
+@@ -14,6 +14,16 @@ Options
+ When mounting an ext3 filesystem, the following option are accepted:
+ (*) == default
+ 
++journal_checksum	Enable checksumming of the journal transactions.
++			This will allow the recovery code in e2fsck and the
++			kernel to detect corruption in the kernel.  It is a
++			compatible change and will be ignored by older kernels.
++
++journal_async_commit	Commit block can be written to disk without waiting
++			for descriptor blocks. If enabled older kernels cannot
++			mount the device. This will enable 'journal_checksum'
++			internally.
++
+ journal=update		Update the ext3 file system's journal to the current
+ 			format.
+ 
diff --git a/lustre/kernel_patches/patches/jbd-journal-chksum-2.6.18-vanilla.patch b/lustre/kernel_patches/patches/jbd-journal-chksum-2.6.18-vanilla.patch
new file mode 100644
index 0000000000..6617dc32b5
--- /dev/null
+++ b/lustre/kernel_patches/patches/jbd-journal-chksum-2.6.18-vanilla.patch
@@ -0,0 +1,616 @@
+Index: linux-2.6.18-8.1.8/fs/jbd/commit.c
+===================================================================
+--- linux-2.6.18-8.1.8.orig/fs/jbd/commit.c
++++ linux-2.6.18-8.1.8/fs/jbd/commit.c
+@@ -21,6 +21,7 @@
+ #include <linux/mm.h>
+ #include <linux/pagemap.h>
+ #include <linux/smp_lock.h>
++#include <linux/crc32.h>
+ 
+ /*
+  * Default IO end handler for temporary BJ_IO buffer_heads.
+@@ -93,19 +94,23 @@ static int inverted_lock(journal_t *jour
+ 	return 1;
+ }
+ 
+-/* Done it all: now write the commit record.  We should have
++/*
++ * Done it all: now submit the commit record.  We should have
+  * cleaned up our previous buffers by now, so if we are in abort
+  * mode we can now just skip the rest of the journal write
+  * entirely.
+  *
+  * Returns 1 if the journal needs to be aborted or 0 on success
+  */
+-static int journal_write_commit_record(journal_t *journal,
+-					transaction_t *commit_transaction)
++static int journal_submit_commit_record(journal_t *journal,
++					transaction_t *commit_transaction,
++					struct buffer_head **cbh,
++					__u32 crc32_sum)
+ {
+ 	struct journal_head *descriptor;
++	struct commit_header *tmp;
+ 	struct buffer_head *bh;
+-	int i, ret;
++	int ret;
+ 	int barrier_done = 0;
+ 
+ 	if (is_journal_aborted(journal))
+@@ -117,21 +122,34 @@ static int journal_write_commit_record(j
+ 
+ 	bh = jh2bh(descriptor);
+ 
+-	/* AKPM: buglet - add `i' to tmp! */
+-	for (i = 0; i < bh->b_size; i += 512) {
+-		journal_header_t *tmp = (journal_header_t*)bh->b_data;
+-		tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
+-		tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
+-		tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
++	tmp = (struct commit_header *)bh->b_data;
++	tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
++	tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
++	tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
++ 		 		
++	if (JFS_HAS_COMPAT_FEATURE(journal,
++				JFS_FEATURE_COMPAT_CHECKSUM)) {
++		tmp->h_chksum_type 	= JFS_CRC32_CHKSUM;
++		tmp->h_chksum_size 	= JFS_CRC32_CHKSUM_SIZE;
++		tmp->h_chksum[0] 	= cpu_to_be32(crc32_sum);
+ 	}
+ 
+-	JBUFFER_TRACE(descriptor, "write commit block");
++	JBUFFER_TRACE(descriptor, "submit commit block");
++	lock_buffer(bh);
++
+ 	set_buffer_dirty(bh);
+-	if (journal->j_flags & JFS_BARRIER) {
++	set_buffer_uptodate(bh);
++	bh->b_end_io = journal_end_buffer_io_sync;
++
++	if (journal->j_flags & JFS_BARRIER &&
++		!JFS_HAS_COMPAT_FEATURE(journal,
++					 JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
++
+ 		set_buffer_ordered(bh);
+ 		barrier_done = 1;
+ 	}
+-	ret = sync_dirty_buffer(bh);
++	ret = submit_bh(WRITE, bh);
++
+ 	/* is it possible for another commit to fail at roughly
+ 	 * the same time as this one?  If so, we don't want to
+ 	 * trust the barrier flag in the super, but instead want
+@@ -152,14 +170,72 @@ static int journal_write_commit_record(j
+ 		clear_buffer_ordered(bh);
+ 		set_buffer_uptodate(bh);
+ 		set_buffer_dirty(bh);
+-		ret = sync_dirty_buffer(bh);
++		ret = submit_bh(WRITE, bh);
+ 	}
+-	put_bh(bh);		/* One for getblk() */
+-	journal_put_journal_head(descriptor);
++	*cbh = bh;
++	return ret;
++}
+ 
+-	return (ret == -EIO);
++/*
++ * This function along with journal_submit_commit_record
++ * allows to write the commit record asynchronously.
++ */
++static int journal_wait_on_commit_record(struct buffer_head *bh)
++{
++	int ret = 0;
++
++	clear_buffer_dirty(bh);
++	wait_on_buffer(bh);
++	
++	if (unlikely(!buffer_uptodate(bh)))
++		ret = -EIO;
++	put_bh(bh);            /* One for getblk() */
++	journal_put_journal_head(bh2jh(bh));
++	
++	return ret;
+ }
+ 
++/*
++ * Wait for all submitted IO to complete.
++ */
++static int journal_wait_on_locked_list(journal_t *journal,
++				       transaction_t *commit_transaction)
++{
++	int ret = 0;
++	struct journal_head *jh;
++
++	while (commit_transaction->t_locked_list) {
++		struct buffer_head *bh;
++
++		jh = commit_transaction->t_locked_list->b_tprev;
++		bh = jh2bh(jh);
++		get_bh(bh);
++		if (buffer_locked(bh)) {
++			spin_unlock(&journal->j_list_lock);
++			wait_on_buffer(bh);
++			if (unlikely(!buffer_uptodate(bh)))
++				ret = -EIO;
++			spin_lock(&journal->j_list_lock);
++		}
++		if (!inverted_lock(journal, bh)) {
++			put_bh(bh);
++			spin_lock(&journal->j_list_lock);
++			continue;
++		}
++		if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
++			__journal_unfile_buffer(jh);
++			jbd_unlock_bh_state(bh);
++			journal_remove_journal_head(bh);
++			put_bh(bh);
++		} else {
++			jbd_unlock_bh_state(bh);
++		}
++		put_bh(bh);
++		cond_resched_lock(&journal->j_list_lock);
++	}
++	return ret;
++}
+++
+ void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
+ {
+ 	int i;
+@@ -293,6 +369,8 @@ void journal_commit_transaction(journal_
+ 	int first_tag = 0;
+ 	int tag_flag;
+ 	int i;
++	struct buffer_head *cbh = NULL; /* For transactional checksums */
++	__u32 crc32_sum = ~0;
+ 
+ 	/*
+ 	 * First job: lock down the current transaction and wait for
+@@ -428,38 +506,14 @@ void journal_commit_transaction(journal_
+ 	journal_submit_data_buffers(journal, commit_transaction);
+ 
+ 	/*
+-	 * Wait for all previously submitted IO to complete.
++	 * Wait for all previously submitted IO to complete if commit
++	 * record is to be written synchronously.
+ 	 */
+ 	spin_lock(&journal->j_list_lock);
+-	while (commit_transaction->t_locked_list) {
+-		struct buffer_head *bh;
+-
+-		jh = commit_transaction->t_locked_list->b_tprev;
+-		bh = jh2bh(jh);
+-		get_bh(bh);
+-		if (buffer_locked(bh)) {
+-			spin_unlock(&journal->j_list_lock);
+-			wait_on_buffer(bh);
+-			if (unlikely(!buffer_uptodate(bh)))
+-				err = -EIO;
+-			spin_lock(&journal->j_list_lock);
+-		}
+-		if (!inverted_lock(journal, bh)) {
+-			put_bh(bh);
+-			spin_lock(&journal->j_list_lock);
+-			continue;
+-		}
+-		if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
+-			__journal_unfile_buffer(jh);
+-			jbd_unlock_bh_state(bh);
+-			journal_remove_journal_head(bh);
+-			put_bh(bh);
+-		} else {
+-			jbd_unlock_bh_state(bh);
+-		}
+-		put_bh(bh);
+-		cond_resched_lock(&journal->j_list_lock);
+-	}
++	if (!JFS_HAS_INCOMPAT_FEATURE(journal,
++		JFS_FEATURE_INCOMPAT_ASYNC_COMMIT))
++		err = journal_wait_on_locked_list(journal,
++						  commit_transaction);
+ 	spin_unlock(&journal->j_list_lock);
+ 
+ 	if (err)
+@@ -627,6 +681,16 @@ void journal_commit_transaction(journal_
+ start_journal_io:
+ 			for (i = 0; i < bufs; i++) {
+ 				struct buffer_head *bh = wbuf[i];
++				/*
++				 * Compute checksum.
++				 */
++				if (JFS_HAS_COMPAT_FEATURE(journal,
++					JFS_FEATURE_COMPAT_CHECKSUM)) {
++					crc32_sum = crc32_be(crc32_sum,
++							(void *)bh->b_data,
++							bh->b_size);
++				}
++
+ 				lock_buffer(bh);
+ 				clear_buffer_dirty(bh);
+ 				set_buffer_uptodate(bh);
+@@ -642,6 +706,23 @@ start_journal_io:
+ 		}
+ 	}
+ 
++	/* Done it all: now write the commit record asynchronously. */
++
++	if (JFS_HAS_INCOMPAT_FEATURE(journal,
++		JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
++		err = journal_submit_commit_record(journal, commit_transaction,
++						 &cbh, crc32_sum);
++		if (err)
++			__journal_abort_hard(journal);
++
++		spin_lock(&journal->j_list_lock);
++		err = journal_wait_on_locked_list(journal,
++						commit_transaction);
++		spin_unlock(&journal->j_list_lock);
++		if (err)
++			__journal_abort_hard(journal);
++	}
++
+ 	/* Lo and behold: we have just managed to send a transaction to
+            the log.  Before we can commit it, wait for the IO so far to
+            complete.  Control buffers being written are on the
+@@ -740,9 +821,15 @@ wait_for_iobuf:
+ 	}
+ 
+ 	jbd_debug(3, "JBD: commit phase 6\n");
+-
+-	if (journal_write_commit_record(journal, commit_transaction))
+-		err = -EIO;
++		
++	if (!JFS_HAS_INCOMPAT_FEATURE(journal,
++		JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
++		err = journal_submit_commit_record(journal, commit_transaction,
++						&cbh, crc32_sum);
++		if (err)
++			__journal_abort_hard(journal);
++	}
++	err = journal_wait_on_commit_record(cbh);
+ 
+ 	if (err)
+ 		__journal_abort_hard(journal);
+Index: linux-2.6.18-8.1.8/include/linux/jbd.h
+===================================================================
+--- linux-2.6.18-8.1.8.orig/include/linux/jbd.h
++++ linux-2.6.18-8.1.8/include/linux/jbd.h
+@@ -148,6 +148,29 @@ typedef struct journal_header_s
+ 	__be32		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
++{
++	__be32		h_magic;
++	__be32          h_blocktype;
++	__be32          h_sequence;
++	unsigned char   h_chksum_type;
++	unsigned char   h_chksum_size;
++	unsigned char 	h_padding[2];
++	__be32 		h_chksum[JFS_CHECKSUM_BYTES];
++};
+ 
+ /* 
+  * The block tag: used to describe a single buffer in the journal 
+@@ -234,12 +257,16 @@ 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_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__
+ 
+@@ -967,6 +994,8 @@ extern int	   journal_check_available_fe
+ 		   (journal_t *, unsigned long, unsigned long, unsigned long);
+ extern int	   journal_set_features 
+ 		   (journal_t *, unsigned long, unsigned long, unsigned long);
++extern int	   journal_clear_features
++		   (journal_t *, unsigned long, unsigned long, unsigned long);
+ extern int	   journal_create     (journal_t *);
+ extern int	   journal_load       (journal_t *journal);
+ extern void	   journal_destroy    (journal_t *);
+Index: linux-2.6.18-8.1.8/fs/jbd/recovery.c
+===================================================================
+--- linux-2.6.18-8.1.8.orig/fs/jbd/recovery.c
++++ linux-2.6.18-8.1.8/fs/jbd/recovery.c
+@@ -21,6 +21,7 @@
+ #include <linux/jbd.h>
+ #include <linux/errno.h>
+ #include <linux/slab.h>
++#include <linux/crc32.h>
+ #endif
+ 
+ /*
+@@ -307,6 +308,37 @@ int journal_skip_recovery(journal_t *jou
+ 	return err;
+ }
+ 
++/*
++ * calc_chksums calculates the checksums for the blocks described in the
++ * descriptor block.
++ */
++static int calc_chksums(journal_t *journal, struct buffer_head *bh,
++		       unsigned long *next_log_block, __u32 *crc32_sum)
++{
++	int i, num_blks, err;
++	unsigned 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 "
++				"%u 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)
+ {
+@@ -318,6 +350,7 @@ 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;
+@@ -409,9 +442,24 @@ 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 (calc_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);
+@@ -506,9 +554,97 @@ 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)) {
++				int chksum_err, chksum_seen;
++				struct commit_header *cbh =
++					(struct commit_header *)bh->b_data;
++				unsigned found_chksum =
++						be32_to_cpu(cbh->h_chksum[0]);
++
++				chksum_err = chksum_seen = 0;
++
++				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 == found_chksum &&
++				    cbh->h_chksum_type == JFS_CRC32_CHKSUM &&
++				    cbh->h_chksum_size ==
++						JFS_CRC32_CHKSUM_SIZE) {
++				       chksum_seen = 1;
++				} else if (!(cbh->h_chksum_type == 0 &&
++					     cbh->h_chksum_size == 0 &&
++					     found_chksum == 0 &&
++					     !chksum_seen)) {
++				/*
++				 * If fs is mounted using an old kernel and then
++				 * kernel with journal_chksum is used then we
++				 * get a situation where the journal flag has
++				 * checksum flag set but checksums are not
++				 * present i.e chksum = 0, in the individual
++				 * commit blocks.
++				 * Hence to avoid checksum failures, in this
++				 * situation, this extra check is added.
++				 */
++						chksum_err = 1;
++				}
++
++				if (chksum_err) {
++					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;
+@@ -544,9 +680,10 @@ 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) {
+Index: linux-2.6.18-8.1.8/fs/jbd/journal.c
+===================================================================
+--- linux-2.6.18-8.1.8.orig/fs/jbd/journal.c
++++ linux-2.6.18-8.1.8/fs/jbd/journal.c
+@@ -66,6 +66,7 @@ EXPORT_SYMBOL(journal_update_format);
+ EXPORT_SYMBOL(journal_check_used_features);
+ EXPORT_SYMBOL(journal_check_available_features);
+ EXPORT_SYMBOL(journal_set_features);
++EXPORT_SYMBOL(journal_clear_features);
+ EXPORT_SYMBOL(journal_create);
+ EXPORT_SYMBOL(journal_load);
+ EXPORT_SYMBOL(journal_destroy);
+@@ -1271,6 +1272,33 @@ int journal_set_features (journal_t *jou
+ 	return 1;
+ }
+ 
++/**
++ * int journal_clear_features () - Clear a given journal feature in the superblock
++ * @journal: Journal to act on.
++ * @compat: bitmask of compatible features
++ * @ro: bitmask of features that force read-only mount
++ * @incompat: bitmask of incompatible features
++ *
++ * Clear a given journal feature as present on the
++ * superblock.  Returns true if the requested features could be reset.
++ *
++ */
++int journal_clear_features (journal_t *journal, unsigned long compat,
++			  unsigned long ro, unsigned long incompat)
++{
++	journal_superblock_t *sb;
++
++	jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
++		  compat, ro, incompat);
++
++	sb = journal->j_superblock;
++
++	sb->s_feature_compat    &= ~cpu_to_be32(compat);
++	sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
++	sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
++
++	return 1;
++}
+ 
+ /**
+  * int journal_update_format () - Update on-disk journal structure.
+Index: linux-2.6.18-8.1.8/fs/Kconfig
+===================================================================
+--- linux-2.6.18-8.1.8.orig/fs/Kconfig
++++ linux-2.6.18-8.1.8/fs/Kconfig
+@@ -140,6 +140,7 @@ config EXT3_FS_SECURITY
+ 
+ config JBD
+ 	tristate
++	select CRC32
+ 	help
+ 	  This is a generic journaling layer for block devices.  It is
+ 	  currently used by the ext3 and OCFS2 file systems, but it could
+Index: linux-2.6.18-8.1.8/Documentation/filesystems/ext3.txt
+===================================================================
+--- linux-2.6.18-8.1.8.orig/Documentation/filesystems/ext3.txt
++++ linux-2.6.18-8.1.8/Documentation/filesystems/ext3.txt
+@@ -14,6 +14,16 @@ Options
+ When mounting an ext3 filesystem, the following option are accepted:
+ (*) == default
+ 
++journal_checksum	Enable checksumming of the journal transactions.
++			This will allow the recovery code in e2fsck and the
++			kernel to detect corruption in the kernel.  It is a
++			compatible change and will be ignored by older kernels.
++
++journal_async_commit	Commit block can be written to disk without waiting
++			for descriptor blocks. If enabled older kernels cannot
++			mount the device. This will enable 'journal_checksum'
++			internally.
++
+ journal=update		Update the ext3 file system's journal to the current
+ 			format.
+ 
diff --git a/lustre/kernel_patches/series/2.6-rhel5.series b/lustre/kernel_patches/series/2.6-rhel5.series
index 076164b54f..34a730c4b6 100644
--- a/lustre/kernel_patches/series/2.6-rhel5.series
+++ b/lustre/kernel_patches/series/2.6-rhel5.series
@@ -9,3 +9,4 @@ export-2.6.18-vanilla.patch
 export-show_task-2.6.18-vanilla.patch
 sd_iostats-2.6-rhel4.patch
 export_symbol_numa-2.6-fc5.patch
+jbd-journal-chksum-2.6.18-vanilla.patch
diff --git a/lustre/kernel_patches/series/2.6-sles10.series b/lustre/kernel_patches/series/2.6-sles10.series
index d6ea003661..ab2e98ac88 100644
--- a/lustre/kernel_patches/series/2.6-sles10.series
+++ b/lustre/kernel_patches/series/2.6-sles10.series
@@ -14,3 +14,4 @@ sd_iostats-2.6-rhel4.patch
 export_symbol_numa-2.6-fc5.patch 
 blkdev_tunables-2.6-sles10.patch
 jbd-stats-2.6-sles10.patch
+jbd-journal-chksum-2.6-sles10.patch
diff --git a/lustre/kernel_patches/series/2.6.18-vanilla.series b/lustre/kernel_patches/series/2.6.18-vanilla.series
index db3efc6f24..8b9da0ef2d 100644
--- a/lustre/kernel_patches/series/2.6.18-vanilla.series
+++ b/lustre/kernel_patches/series/2.6.18-vanilla.series
@@ -13,3 +13,4 @@ sd_iostats-2.6-rhel4.patch
 export_symbol_numa-2.6.18.patch 
 jbd-16tb-overflow-fixes.patch
 jbd-check-for-unmapped-buffer.patch
+jbd-journal-chksum-2.6.18-vanilla.patch
-- 
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