Index: linux-3.0.101-0.5/fs/ext4/ext4.h
===================================================================
--- linux-3.0.101-0.5.orig/fs/ext4/ext4.h
+++ linux-3.0.101-0.5/fs/ext4/ext4.h
@@ -893,7 +893,8 @@ struct ext4_inode_info {
 /*
  * Mount flags
  */
-#define EXT4_MOUNT_OLDALLOC		0x00002  /* Don't use the new Orlov allocator */
+#define EXT4_MOUNT_NO_MBCACHE		0x00001 /* Disable mbcache */
+#define EXT4_MOUNT_OLDALLOC		0x00002 /* Don't use the new Orlov allocator */
 #define EXT4_MOUNT_GRPID		0x00004	/* Create files with directory's group */
 #define EXT4_MOUNT_DEBUG		0x00008	/* Some debugging messages */
 #define EXT4_MOUNT_ERRORS_CONT		0x00010	/* Continue on errors */
Index: linux-3.0.101-0.5/fs/ext4/super.c
===================================================================
--- linux-3.0.101-0.5.orig/fs/ext4/super.c
+++ linux-3.0.101-0.5/fs/ext4/super.c
@@ -1364,6 +1364,7 @@ enum {
 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
 	Opt_inode_readahead_blks, Opt_journal_ioprio,
 	Opt_dioread_nolock, Opt_dioread_lock,
+	Opt_no_mbcache,
 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
 };
 
@@ -1436,6 +1437,7 @@ static const match_table_t tokens = {
 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
 	{Opt_dioread_nolock, "dioread_nolock"},
 	{Opt_dioread_lock, "dioread_lock"},
+	{Opt_no_mbcache, "no_mbcache"},
 	{Opt_discard, "discard"},
 	{Opt_nodiscard, "nodiscard"},
 	{Opt_init_itable, "init_itable=%u"},
@@ -1934,6 +1936,9 @@ set_qf_format:
 		case Opt_noinit_itable:
 			clear_opt(sb, INIT_INODE_TABLE);
 			break;
+		case Opt_no_mbcache:
+			set_opt(sb, NO_MBCACHE);
+			break;
 		default:
 			ext4_msg(sb, KERN_ERR,
 			       "Unrecognized mount option \"%s\" "
Index: linux-3.0.101-0.5/fs/ext4/xattr.c
===================================================================
--- linux-3.0.101-0.5.orig/fs/ext4/xattr.c
+++ linux-3.0.101-0.5/fs/ext4/xattr.c
@@ -86,7 +86,8 @@
 # define ea_bdebug(f...)
 #endif
 
-static void ext4_xattr_cache_insert(struct buffer_head *);
+static void ext4_xattr_cache_insert(struct super_block *,
+				    struct buffer_head *);
 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
 						 struct ext4_xattr_header *,
 						 struct mb_cache_entry **);
@@ -332,7 +333,7 @@ bad_block:
 		error = -EIO;
 		goto cleanup;
 	}
-	ext4_xattr_cache_insert(bh);
+	ext4_xattr_cache_insert(inode->i_sb, bh);
 	entry = BFIRST(bh);
 	error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1,
 				      inode);
@@ -492,7 +493,7 @@ ext4_xattr_block_list(struct dentry *den
 		error = -EIO;
 		goto cleanup;
 	}
-	ext4_xattr_cache_insert(bh);
+	ext4_xattr_cache_insert(inode->i_sb, bh);
 	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 
 cleanup:
@@ -589,7 +590,9 @@ ext4_xattr_release_block(handle_t *handl
 	struct mb_cache_entry *ce = NULL;
 	int error = 0;
 
-	ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
+	if (!test_opt(inode->i_sb, NO_MBCACHE))
+		ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev,
+					bh->b_blocknr);
 	error = ext4_journal_get_write_access(handle, bh);
 	if (error)
 		goto out;
@@ -992,8 +995,10 @@ ext4_xattr_block_set(handle_t *handle, s
 #define header(x) ((struct ext4_xattr_header *)(x))
 
 	if (s->base) {
-		ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
-					bs->bh->b_blocknr);
+		if (!test_opt(inode->i_sb, NO_MBCACHE))
+			ce = mb_cache_entry_get(ext4_xattr_cache,
+						bs->bh->b_bdev,
+						bs->bh->b_blocknr);
 		error = ext4_journal_get_write_access(handle, bs->bh);
 		if (error)
 			goto cleanup;
@@ -1010,7 +1015,7 @@ ext4_xattr_block_set(handle_t *handle, s
 				if (!IS_LAST_ENTRY(s->first))
 					ext4_xattr_rehash(header(s->base),
 							  s->here);
-				ext4_xattr_cache_insert(bs->bh);
+				ext4_xattr_cache_insert(sb, bs->bh);
 			}
 			unlock_buffer(bs->bh);
 			if (error == -EIO)
@@ -1093,7 +1098,8 @@ inserted:
 				if (error)
 					goto cleanup_dquot;
 			}
-			mb_cache_entry_release(ce);
+			if (ce)
+				mb_cache_entry_release(ce);
 			ce = NULL;
 		} else if (bs->bh && s->base == bs->bh->b_data) {
 			/* We were modifying this block in-place. */
@@ -1144,7 +1150,7 @@ getblk_failed:
 			memcpy(new_bh->b_data, s->base, new_bh->b_size);
 			set_buffer_uptodate(new_bh);
 			unlock_buffer(new_bh);
-			ext4_xattr_cache_insert(new_bh);
+			ext4_xattr_cache_insert(sb, new_bh);
 			error = ext4_handle_dirty_metadata(handle,
 							   inode, new_bh);
 			if (error)
@@ -1865,12 +1871,15 @@ ext4_xattr_put_super(struct super_block
  * Returns 0, or a negative error number on failure.
  */
 static void
-ext4_xattr_cache_insert(struct buffer_head *bh)
+ext4_xattr_cache_insert(struct super_block *sb, struct buffer_head *bh)
 {
 	__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
 	struct mb_cache_entry *ce;
 	int error;
 
+	if (test_opt(sb, NO_MBCACHE))
+		return;
+
 	ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
 	if (!ce) {
 		ea_bdebug(bh, "out of memory");
@@ -1943,6 +1952,8 @@ ext4_xattr_cache_find(struct inode *inod
 	__u32 hash = le32_to_cpu(header->h_hash);
 	struct mb_cache_entry *ce;
 
+	if (test_opt(inode->i_sb, NO_MBCACHE))
+		return NULL;
 	if (!header->h_hash)
 		return NULL;  /* never share */
 	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);