diff -auNr mtd-snapshot-20041008/fs/jffs2/build.c mtd-preepmpt-fix/fs/jffs2/build.c
--- mtd-snapshot-20041008/fs/jffs2/build.c	2003-10-29 02:00:34.000000000 +0300
+++ mtd-preepmpt-fix/fs/jffs2/build.c	2004-11-03 19:20:49.769732102 +0300
@@ -314,6 +314,7 @@
 
 	init_MUTEX(&c->alloc_sem);
 	init_MUTEX(&c->erase_free_sem);
+	init_rwsem(&c->wbuf_sem);
 	init_waitqueue_head(&c->erase_wait);
 	init_waitqueue_head(&c->inocache_wq);
 	spin_lock_init(&c->erase_completion_lock);
diff -auNr mtd-snapshot-20041008/fs/jffs2/wbuf.c mtd-preepmpt-fix/fs/jffs2/wbuf.c
--- mtd-snapshot-20041008/fs/jffs2/wbuf.c	2004-09-12 02:00:12.000000000 +0400
+++ mtd-preepmpt-fix/fs/jffs2/wbuf.c	2004-11-03 19:20:49.761733507 +0300
@@ -392,7 +392,7 @@
    1: Pad, do not adjust nextblock free_size
    2: Pad, adjust nextblock free_size
 */
-static int __jffs2_flush_wbuf(struct jffs2_sb_info *c, int pad)
+static int __jffs2_flush_wbuf(struct jffs2_sb_info *c, int pad, int alloc_wbuf_sem)
 {
 	int ret;
 	size_t retlen;
@@ -408,8 +408,11 @@
 		BUG();
 	}
 
+	if (alloc_wbuf_sem)
+		down_write(&c->wbuf_sem);
+
 	if(!c->wbuf || !c->wbuf_len)
-		return 0;
+		goto exit;
 
 	/* claim remaining space on the page
 	   this happens, if we have a change to a new block,
@@ -458,7 +461,7 @@
 
 		jffs2_wbuf_recover(c);
 
-		return ret; 
+		goto exit;
 	}
 
 	spin_lock(&c->erase_completion_lock);
@@ -497,6 +500,9 @@
 	/* adjust write buffer offset, else we get a non contiguous write bug */
 	c->wbuf_ofs += c->wbuf_pagesize;
 	c->wbuf_len = 0;
+exit:
+	if (alloc_wbuf_sem)
+		up_write(&c->wbuf_sem);
 	return 0;
 }
 
@@ -525,7 +531,7 @@
 	if (c->unchecked_size) {
 		/* GC won't make any progress for a while */
 		D1(printk(KERN_DEBUG "jffs2_flush_wbuf_gc() padding. Not finished checking\n"));
-		ret = __jffs2_flush_wbuf(c, 2);
+		ret = __jffs2_flush_wbuf(c, 2, 1);
 	} else while (old_wbuf_len &&
 		      old_wbuf_ofs == c->wbuf_ofs) {
 
@@ -537,7 +543,7 @@
 		if (ret) {
 			/* GC failed. Flush it with padding instead */
 			down(&c->alloc_sem);
-			ret = __jffs2_flush_wbuf(c, 2);
+			ret = __jffs2_flush_wbuf(c, 2, 1);
 			break;
 		}
 		down(&c->alloc_sem);
@@ -552,10 +558,9 @@
 /* Pad write-buffer to end and write it, wasting space. */
 int jffs2_flush_wbuf_pad(struct jffs2_sb_info *c)
 {
-	return __jffs2_flush_wbuf(c, 1);
+	return __jffs2_flush_wbuf(c, 1, 1);
 }
 
-
 #define PAGE_DIV(x) ( (x) & (~(c->wbuf_pagesize - 1)) )
 #define PAGE_MOD(x) ( (x) & (c->wbuf_pagesize - 1) )
 int jffs2_flash_writev(struct jffs2_sb_info *c, const struct kvec *invecs, unsigned long count, loff_t to, size_t *retlen, uint32_t ino)
@@ -575,6 +580,8 @@
 	if (!c->wbuf)
 		return jffs2_flash_direct_writev(c, invecs, count, to, retlen);
 	
+	down_write(&c->wbuf_sem);
+
 	/* If wbuf_ofs is not initialized, set it to target address */
 	if (c->wbuf_ofs == 0xFFFFFFFF) {
 		c->wbuf_ofs = PAGE_DIV(to);
@@ -592,12 +599,12 @@
 		/* It's a write to a new block */
 		if (c->wbuf_len) {
 			D1(printk(KERN_DEBUG "jffs2_flash_writev() to 0x%lx causes flush of wbuf at 0x%08x\n", (unsigned long)to, c->wbuf_ofs));
-			ret = jffs2_flush_wbuf_pad(c);
+			ret = __jffs2_flush_wbuf(c, 1, 1);
 			if (ret) {
 				/* the underlying layer has to check wbuf_len to do the cleanup */
 				D1(printk(KERN_WARNING "jffs2_flush_wbuf() called from jffs2_flash_writev() failed %d\n", ret));
 				*retlen = 0;
-				return ret;
+				goto exit;
 			}
 		}
 		/* set pointer to new block */
@@ -658,14 +665,14 @@
 		}			
 		
 		/* write buffer is full, flush buffer */
-		ret = __jffs2_flush_wbuf(c, 0);
+		ret = __jffs2_flush_wbuf(c, 0, 0);
 		if (ret) {
 			/* the underlying layer has to check wbuf_len to do the cleanup */
 			D1(printk(KERN_WARNING "jffs2_flush_wbuf() called from jffs2_flash_writev() failed %d\n", ret));
 			/* Retlen zero to make sure our caller doesn't mark the space dirty.
 			   We've already done everything that's necessary */
 			*retlen = 0;
-			return ret;
+			goto exit;
 		}
 		outvec_to += donelen;
 		c->wbuf_ofs = outvec_to;
@@ -709,7 +716,6 @@
 
 	if (splitvec != -1) {
 		uint32_t remainder;
-		int ret;
 
 		remainder = outvecs[splitvec].iov_len - split_ofs;
 		outvecs[splitvec].iov_len = split_ofs;
@@ -721,7 +727,7 @@
 			   c->wbuf is empty. 
 			*/
 			*retlen = donelen;
-			return ret;
+			goto exit;
 		}
 		
 		donelen += wbuf_retlen;
@@ -760,7 +766,11 @@
 	if (c->wbuf_len && ino)
 		jffs2_wbuf_dirties_inode(c, ino);
 
-	return 0;
+	ret = 0;
+	
+exit:
+	up_write(&c->wbuf_sem);
+	return ret;
 }
 
 /*
@@ -789,6 +799,8 @@
 
 	/* Read flash */
 	if (!jffs2_can_mark_obsolete(c)) {
+		down_read(&c->wbuf_sem);
+
 		ret = c->mtd->read_ecc(c->mtd, ofs, len, retlen, buf, NULL, c->oobinfo);
 
 		if ( (ret == -EBADMSG) && (*retlen == len) ) {
@@ -811,23 +823,23 @@
 
 	/* if no writebuffer available or write buffer empty, return */
 	if (!c->wbuf_pagesize || !c->wbuf_len)
-		return ret;
+		goto exit;
 
 	/* if we read in a different block, return */
 	if ( (ofs & ~(c->sector_size-1)) != (c->wbuf_ofs & ~(c->sector_size-1)) ) 
-		return ret;	
+		goto exit;
 
 	if (ofs >= c->wbuf_ofs) {
 		owbf = (ofs - c->wbuf_ofs);	/* offset in write buffer */
 		if (owbf > c->wbuf_len)		/* is read beyond write buffer ? */
-			return ret;
+			goto exit;
 		lwbf = c->wbuf_len - owbf;	/* number of bytes to copy */
 		if (lwbf > len)	
 			lwbf = len;
 	} else {	
 		orbf = (c->wbuf_ofs - ofs);	/* offset in read buffer */
 		if (orbf > len)			/* is write beyond write buffer ? */
-			return ret;
+			goto exit;
 		lwbf = len - orbf; 		/* number of bytes to copy */
 		if (lwbf > c->wbuf_len)	
 			lwbf = c->wbuf_len;
@@ -835,6 +847,8 @@
 	if (lwbf > 0)
 		memcpy(buf+orbf,c->wbuf+owbf,lwbf);
 
+exit:
+	up_read(&c->wbuf_sem);
 	return ret;
 }
 
diff -auNr mtd-snapshot-20041008/include/linux/jffs2_fs_sb.h mtd-preepmpt-fix/include/linux/jffs2_fs_sb.h
--- mtd-snapshot-20041008/include/linux/jffs2_fs_sb.h	2003-10-09 02:00:05.000000000 +0400
+++ mtd-preepmpt-fix/include/linux/jffs2_fs_sb.h	2004-11-03 19:20:50.058681364 +0300
@@ -36,8 +36,9 @@
 	struct semaphore alloc_sem;	/* Used to protect all the following 
 					   fields, and also to protect against
 					   out-of-order writing of nodes.
-					   And GC.
-					*/
+					   And GC. Also protects the write buffer
+					   against concurrent writes. */
+	struct rw_semaphore wbuf_sem;	/* Protects the write buffer while it is read */
 	uint32_t cleanmarker_size;	/* Size of an _inline_ CLEANMARKER
 					 (i.e. zero for OOB CLEANMARKER */
 
diff -auNr mtd-snapshot-20041008/patches/patchin.sh mtd-preepmpt-fix/patches/patchin.sh
--- mtd-snapshot-20041008/patches/patchin.sh	1970-01-01 03:00:00.000000000 +0300
+++ mtd-preepmpt-fix/patches/patchin.sh	2004-10-04 02:00:14.000000000 +0400
@@ -0,0 +1,392 @@
+#!/bin/sh
+#
+# Patch mtd into kernel
+#
+# usage:patch [-j] kernelpath
+# 	kernelpath must be given
+#	-j includes filesystems (jffs, jffs2)
+#	
+# Works for Kernels >= 2.4.11 full functional
+# Works for Kernels >= 2.4 and <= 2.4.10 partly (JFFS2 support is missing)
+# For 2.2 Kernels it's actually disabled, as I have none to test it.
+#
+# You can use it for pristine kernels and for already patches kernels too.
+#
+# Detects Kernelversion and applies neccecary modifications
+# For Kernelversions < 2.4.20 ZLIB-Patch is applied, if 
+# filesystem option is set and ZLIB-Patch is not already there 
+#
+# Maybe some sed/awk experts would make it better, but I'm not
+# one of them. Feel free to make it better
+# 
+# Thomas (tglx@linutronix.de)
+#
+# $Id: patchin.sh,v 1.28 2004/10/02 22:14:38 gleixner Exp $
+#
+# 24-05-2004 havasi Patch fs/Kconfig
+# 05-05-2004 tglx Include include/mtd
+# 12-06-2003 dwmw2 Leave out JFFS1, do Makefile.common only if it exists.
+# 27-05-2003 dwmw2 Link Makefile to Makefile.common since we moved them around
+# 02-10-2003 tglx replaced grep -m by head -n 1, as older grep versions don't support -m	
+# 03-08-2003 tglx -c option for copying files to kernel tree instead of linking
+#		  moved file selection to variables
+
+# Preset variables
+FILESYSTEMS="no"
+BK="no"
+VERSION=0
+PATCHLEVEL=0
+SUBLEVEL=0
+ZLIBPATCH="no"
+RSLIBPATCH="no"
+DOCPATCH="no"
+CONFIG="Config.in"
+LNCP="ln -sf"
+METHOD="Link"
+
+
+# MTD - files and directories
+MTD_DIRS="drivers/mtd drivers/mtd/chips drivers/mtd/devices drivers/mtd/maps drivers/mtd/nand include/linux/mtd include/mtd"
+MTD_FILES="*.[ch] Makefile Rules.make"
+
+# JFFS2 files and directories
+FS_DIRS="fs/jffs2"
+FS_FILES="*.[ch] Makefile Rules.make"
+# kernel version < 2.4.20 needs zlib headers
+FS_INC_BEL2420="jffs*.h workqueue.h z*.h rb*.h suspend.h"
+# kernel version < 2.5.x
+FS_INC_BEL25="jffs2*.h workqueue.h rb*.h suspend.h"
+# kernelversion >= 2.5
+FS_INC_25="jffs2*.h"
+FS_INC_DIR="include/linux"
+
+# shared ZLIB patch
+ZLIB_DIRS="lib/zlib_deflate lib/zlib_inflate"
+ZLIB_FILES="*.[ch] Makefile"
+# shared REED_SOLOMON patch
+RSLIB_DIRS="lib/reed_solomon"
+RSLIB_FILES="*.[ch]"
+RSLIB_INC_DIR="include/linux"
+RSLIB_INC="rslib.h"
+# Documentation
+DOC_DIRS="Documentation/DocBook"
+DOC_FILES="*.tmpl"
+
+# Make text utils not suck
+export LANG=C
+export LC_ALL=C
+
+# Display usage of this script
+usage () {
+	echo "usage:  $0 [-c] [-j] kernelpath"
+	echo "   -c  -- copy files to kernel tree instead of building links"
+	echo "   -j  -- include jffs2 filesystem" 
+	echo "   -b  -- Check files out for write from BK" 
+	exit 1
+}
+
+# Function to patch kernel source
+patchit () {
+for DIR in $PATCH_DIRS 
+do
+	echo $DIR
+	mkdir -p $DIR
+	cd $TOPDIR/$DIR
+	FILES=`ls $PATCH_FILES 2>/dev/null`
+	if [ "$BK" = "yes" -a -d $DIR/SCCS ]; then
+	    pushd $LINUXDIR/$DIR
+	    bk co -ql $FILES
+	    popd
+	fi
+	for FILE in $FILES 
+	do
+		# If there's a Makefile.common it goes in place of Makefile
+		if [ "$FILE" = "Makefile" -a -r $TOPDIR/$DIR/Makefile.common ]; then
+		    if test $PATCHLEVEL -lt 5; then
+			rm -f $LINUXDIR/$DIR/Makefile.common 2>/dev/null
+			$LNCP $TOPDIR/$DIR/Makefile.common $LINUXDIR/$DIR/Makefile.common
+			SRCFILE=Makefile.24
+		    else
+			SRCFILE=Makefile.common
+		    fi
+		else
+		    SRCFILE=$FILE
+		fi
+		rm -f $LINUXDIR/$DIR/$FILE 2>/dev/null
+		$LNCP $TOPDIR/$DIR/$SRCFILE $LINUXDIR/$DIR/$FILE
+	done
+	cd $LINUXDIR
+done	
+}
+
+
+# Start of script
+
+# Get commandline options
+while getopts cjb opt
+do
+    case "$opt" in
+      j)  FILESYSTEMS=yes;;
+      c)  LNCP="cp -f"; METHOD="Copy";;
+      b)  BK=yes;;
+      \?)
+	  usage;
+    esac
+done
+shift `expr $OPTIND - 1`
+LINUXDIR=$1
+
+if [ -z $LINUXDIR ]; then
+    usage;
+fi
+
+if [ ! -f $LINUXDIR/Makefile -a "$BK" = "yes" ]; then
+    pushd $LINUXDIR
+    bk co Makefile
+    popd
+fi
+
+# Check if kerneldir contains a Makefile
+if [ ! -f $LINUXDIR/Makefile ] 
+then 
+	echo "Directory $LINUXDIR does not exist or is not a kernel source directory";
+	exit 1;
+fi
+
+# Get kernel version
+VERSION=`grep -s VERSION <$LINUXDIR/Makefile | head -n 1 | sed s/'VERSION = '//`
+PATCHLEVEL=`grep -s PATCHLEVEL <$LINUXDIR/Makefile | head -n 1 | sed s/'PATCHLEVEL = '//`
+SUBLEVEL=`grep -s SUBLEVEL <$LINUXDIR/Makefile | head -n 1 | sed s/'SUBLEVEL = '//`
+
+# Can we handle this ?
+if test $VERSION -ne 2 -o $PATCHLEVEL -lt 4
+then 
+	echo "Cannot patch kernel version $VERSION.$PATCHLEVEL.$SUBLEVEL";
+	exit 1;
+fi
+
+# Use Kconfig instead of Config.in for Kernels >= 2.5
+if test $PATCHLEVEL -gt 4
+then
+	CONFIG="Kconfig";
+fi
+MTD_FILES="$MTD_FILES $CONFIG"
+
+# Have we to use ZLIB PATCH ? 
+if [ "$FILESYSTEMS" = "yes" ]
+then
+	PATCHDONE=`grep -s zlib_deflate $LINUXDIR/lib/Makefile | head -n 1`
+	if test $PATCHLEVEL -eq 4 -a $SUBLEVEL -lt 20 
+	then
+		if [ "$PATCHDONE" = "" ] 
+		then
+			ZLIBPATCH=yes;
+		fi
+	fi
+fi
+
+# Have we to use REED_SOLOMON PATCH ?
+PATCHDONE=`grep -s reed_solomon $LINUXDIR/lib/Makefile | head -n 1`
+if [ "$PATCHDONE" = "" ]
+then
+	RSLIBPATCH=yes;
+fi
+
+# Have we to use DOCUMENTATION PATCH ?
+PATCHDONE=`grep -s mtdnand $LINUXDIR/$DOC_DIRS/Makefile | head -n 1`
+if [ "$PATCHDONE" = "" ]
+then
+    if test $PATCHLEVEL -gt 4 
+    then
+	DOCPATCH=yes;
+    fi
+fi
+
+# Check which header files we need depending on kernel version
+HDIR="include/linux"
+if test $PATCHLEVEL -eq 4 
+then	
+	# 2.4 below 2.4.20 zlib headers are neccecary
+	if test $SUBLEVEL -lt 20
+	then
+		JFFS2_H=$FS_INC_BEL2420
+	else
+		JFFS2_H=$FS_INC_BEL25
+	fi
+else
+	#	>= 2.5
+	JFFS2_H=$FS_INC_25
+fi
+
+echo Patching $LINUXDIR 
+echo Include Filesytems: $FILESYSTEMS
+echo Zlib-Patch needed: $ZLIBPATCH
+echo RS-Lib-Patch needed: $RSLIBPATCH
+echo Documentation Patch needed: $DOCPATCH
+echo Method: $METHOD
+read -p "Can we start now ? [y/N]" ANSWER
+echo ""
+
+if [ "$ANSWER" != "y" ]
+then
+	echo Patching Kernel cancelled
+	exit 1;
+fi
+
+# Here we go
+cd `dirname $0`
+THISDIR=`pwd`
+TOPDIR=`dirname $THISDIR`
+
+cd $LINUXDIR
+
+# make directories, if necessary
+# remove existing files/links and link/copy the new ones
+echo "Patching MTD"
+PATCH_DIRS=$MTD_DIRS
+PATCH_FILES=$MTD_FILES
+patchit;
+
+# check, if we have to include JFFS(2)
+if [ "$FILESYSTEMS" = "yes" ]
+then
+	echo "Patching JFFS(2)"
+	
+	PATCH_DIRS=$FS_DIRS
+	PATCH_FILES=$FS_FILES
+	patchit;
+
+	PATCH_DIRS=$FS_INC_DIR
+	PATCH_FILES=$JFFS2_H
+	patchit;
+
+	# this is the ugly part	
+	PATCHDONE=`grep -s jffs2 fs/Makefile | head -n 1`
+	if [ "$PATCHDONE" = "" ]
+	then
+		echo "Add JFFS2 to Makefile and Config.in manually. JFFS2 is included as of 2.4.12"	
+	else
+		if test $PATCHLEVEL -lt 5
+		then
+			JFFS=`grep -n JFFS fs/Config.in | head -n 1 | sed s/:.*//`
+			CRAMFS=`grep -n CRAMFS fs/Config.in | head -n 1 | sed s/:.*//`
+			let JFFS=JFFS-1
+			let CRAMFS=CRAMFS-1
+			sed "$JFFS"q fs/Config.in >Config.tmp
+			cat $TOPDIR/fs/Config.in >>Config.tmp
+			sed 1,"$CRAMFS"d fs/Config.in >>Config.tmp
+			mv -f Config.tmp fs/Config.in
+			
+			if [ -f include/linux/crc32.h ] 
+			then
+				# check, if it is already defined there
+				CRC32=`grep -s 'crc32(' include/linux/crc32.h | head -n 1`
+				if [ "$CRC32" = "" ]
+				then
+					# patch in header from fs/jffs2
+					LASTLINE=`grep -n '#endif' include/linux/crc32.h | head -n 1 | sed s/:.*//`
+					let LASTLINE=LASTLINE-1
+					sed "$LASTLINE"q include/linux/crc32.h >Crc32.tmp
+					cat fs/jffs2/crc32.h >>Crc32.tmp
+					echo "#endif" >>Crc32.tmp
+					mv -f Crc32.tmp include/linux/crc32.h
+				fi
+			else
+				rm -f include/linux/crc32.h
+				$LNCP $TOPDIR/fs/jffs2/crc32.h include/linux
+			fi
+		
+                else
+			JFFS=`grep -n JFFS fs/Kconfig | head -n 1 | sed s/:.*//`
+			CRAMFS=`grep -n CRAMFS fs/Kconfig | head -n 1 | sed s/:.*//`
+			let JFFS=JFFS-1
+			let CRAMFS=CRAMFS-1
+			sed "$JFFS"q fs/Kconfig >Kconfig.tmp
+			cat $TOPDIR/fs/Kconfig >>Kconfig.tmp
+			sed 1,"$CRAMFS"d fs/Kconfig >>Kconfig.tmp
+			mv -f Kconfig.tmp fs/Kconfig
+                fi
+	fi
+fi
+
+if [ "$ZLIBPATCH" = "yes" ]
+then
+	echo "Patching ZLIB"
+	
+	PATCH_DIRS=$ZLIB_DIRS
+	PATCH_FILES=$ZLIB_FILES
+	patchit;
+
+	patch -p1 -i $TOPDIR/lib/patch-Makefile
+fi
+
+echo "Patching RS Lib"
+if [ "$RSLIBPATCH" = "yes" ]
+then
+	if test $PATCHLEVEL -eq 4 
+	then
+		patch -p1 -i $TOPDIR/lib/Makefile24-rs.diff
+		patch -p1 -i $TOPDIR/lib/Config.in-rs.diff
+	else
+		patch -p1 -i $TOPDIR/lib/Makefile26-rs.diff
+		patch -p1 -i $TOPDIR/lib/Kconfig-rs.diff
+	fi
+	
+	mkdir -p lib/reed_solomon
+	
+fi
+
+	PATCH_DIRS=$RSLIB_DIRS
+	PATCH_FILES=$RSLIB_FILES
+	patchit;
+
+	PATCH_DIRS=$RSLIB_INC_DIR
+	PATCH_FILES=$RSLIB_INC
+	patchit;
+	if test $PATCHLEVEL -eq 6 
+	then
+		mv -f lib/reed_solomon/rslib.c lib/reed_solomon/reed_solomon.c
+	fi
+
+if test $PATCHLEVEL -eq 4 
+then
+	PATCH_DIRS=$RSLIB_DIRS
+	PATCH_FILES="Makefile24"
+	patchit;
+	rm -f $LINUXDIR/lib/reed_solomon/Makefile 2>/dev/null
+	mv -f $LINUXDIR/lib/reed_solomon/Makefile24 $LINUXDIR/lib/reed_solomon/Makefile
+else	
+	PATCH_DIRS=$RSLIB_DIRS
+	PATCH_FILES="Makefile26"
+	patchit;
+	rm -f $LINUXDIR/lib/reed_solomon/Makefile 2>/dev/null
+	mv -f $LINUXDIR/lib/reed_solomon/Makefile26 $LINUXDIR/lib/reed_solomon/Makefile
+fi
+
+echo "Patching Documentation"
+if [ "$DOCPATCH" = "yes" ]
+then
+    patch -p1 -i $TOPDIR/$DOC_DIRS/Makefile.diff
+fi
+
+PATCH_DIRS=$DOC_DIRS
+PATCH_FILES=$DOC_FILES
+patchit;
+
+
+echo "Patching done"
+
+# some BUG() definitions were moved to asm/bug.h in the 2.5 kernels
+#  so fake having one to avoid build errors.
+if test $PATCHLEVEL -lt 5; then
+	if [ ! -r $LINUXDIR/include/asm/bug.h ]; then
+		touch $LINUXDIR/include/asm/bug.h
+	fi
+fi
+
+if test $PATCHLEVEL -lt 5
+then 
+	# FIXME: SED/AWK experts should know how to do it automagic
+	echo "Please update Documentation/Configure.help from $TOPDIR/Documentation/Configure.help"
+fi
+