Index: linux-2.6.18-238.12.1/fs/ext4/ext4.h
===================================================================
--- linux-2.6.18-238.12.1.orig/fs/ext4/ext4.h	2011-09-21 17:55:44.627741549 +0200
+++ linux-2.6.18-238.12.1/fs/ext4/ext4.h	2011-09-21 18:05:20.974106450 +0200
@@ -971,6 +971,7 @@
 #ifdef CONFIG_QUOTA
 	char *s_qf_names[MAXQUOTAS];		/* Names of quota files with journalled quota */
 	int s_jquota_fmt;			/* Format of quota to use */
+	unsigned long s_qf_inums[MAXQUOTAS];    /* Quota file inodes */
 #endif
 	unsigned int s_want_extra_isize; /* New inodes should reserve # bytes */
 	struct rb_root system_blks;
@@ -1171,6 +1172,7 @@
 #define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010
 #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020
 #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040
+#define EXT4_FEATURE_RO_COMPAT_QUOTA		0x0100
 
 #define EXT4_FEATURE_INCOMPAT_COMPRESSION	0x0001
 #define EXT4_FEATURE_INCOMPAT_FILETYPE		0x0002