diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 076c5d2..b973af6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -231,12 +231,16 @@ struct ext4_io_submit {
 #define EXT4_MAX_BLOCK_LOG_SIZE		16
 #ifdef __KERNEL__
 # define EXT4_BLOCK_SIZE(s)		((s)->s_blocksize)
+# define EXT4_CLUSTER_SIZE(s)		(EXT4_SB(s)->s_clustersize)
 #else
 # define EXT4_BLOCK_SIZE(s)		(EXT4_MIN_BLOCK_SIZE << (s)->s_log_block_size)
+# define EXT2_CLUSTER_SIZE(s)		(EXT2_MIN_BLOCK_SIZE << \
+						(s)->s_log_cluster_size)
 #endif
 #define	EXT4_ADDR_PER_BLOCK(s)		(EXT4_BLOCK_SIZE(s) / sizeof(__u32))
 #ifdef __KERNEL__
 # define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)
+# define EXT4_CLUSTER_SIZE_BITS(s)	(EXT4_SB(s)->s_clustersize_bits)
 #else
 # define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)
 #endif
@@ -302,6 +306,7 @@ struct flex_groups {
 #define EXT4_DESC_SIZE(s)		(EXT4_SB(s)->s_desc_size)
 #ifdef __KERNEL__
 # define EXT4_BLOCKS_PER_GROUP(s)	(EXT4_SB(s)->s_blocks_per_group)
+# define EXT4_CLUSTERS_PER_GROUP(s)	(EXT4_SB(s)->s_clusters_per_group)
 # define EXT4_DESC_PER_BLOCK(s)		(EXT4_SB(s)->s_desc_per_block)
 # define EXT4_INODES_PER_GROUP(s)	(EXT4_SB(s)->s_inodes_per_group)
 # define EXT4_DESC_PER_BLOCK_BITS(s)	(EXT4_SB(s)->s_desc_per_block_bits)
@@ -957,9 +962,9 @@ struct ext4_super_block {
 /*10*/	__le32	s_free_inodes_count;	/* Free inodes count */
 	__le32	s_first_data_block;	/* First Data Block */
 	__le32	s_log_block_size;	/* Block size */
-	__le32	s_obso_log_frag_size;	/* Obsoleted fragment size */
+	__le32	s_log_cluster_size;	/* Allocation cluster size */
 /*20*/	__le32	s_blocks_per_group;	/* # Blocks per group */
-	__le32	s_obso_frags_per_group;	/* Obsoleted fragments per group */
+	__le32	s_clusters_per_group;	/* # Clusters per group */
 	__le32	s_inodes_per_group;	/* # Inodes per group */
 	__le32	s_mtime;		/* Mount time */
 /*30*/	__le32	s_wtime;		/* Write time */
@@ -1055,7 +1060,10 @@ struct ext4_super_block {
 	__u8	s_last_error_func[32];	/* function where the error happened */
 #define EXT4_S_ERR_END offsetof(struct ext4_super_block, s_mount_opts)
 	__u8	s_mount_opts[64];
-	__le32	s_reserved[112];        /* Padding to the end of the block */
+	__le32	s_usr_quota_inum;	/* inode for tracking user quota */
+	__le32	s_grp_quota_inum;	/* inode for tracking group quota */
+	__le32	s_overhead_clusters;	/* overhead blocks/clusters in fs */
+	__le32  s_reserved[109];        /* Padding to the end of the block */
 };
 
 #define EXT4_S_ERR_LEN (EXT4_S_ERR_END - EXT4_S_ERR_START)
@@ -1075,6 +1083,7 @@ struct ext4_sb_info {
 	unsigned long s_desc_size;	/* Size of a group descriptor in bytes */
 	unsigned long s_inodes_per_block;/* Number of inodes per block */
 	unsigned long s_blocks_per_group;/* Number of blocks in a group */
+	unsigned long s_clusters_per_group; /* Number of clusters in a group */
 	unsigned long s_inodes_per_group;/* Number of inodes in a group */
 	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
 	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
@@ -1083,6 +1092,8 @@ struct ext4_sb_info {
 	ext4_group_t s_blockfile_groups;/* Groups acceptable for non-extent files */
 	unsigned long s_overhead_last;  /* Last calculated overhead */
 	unsigned long s_blocks_last;    /* Last seen block count */
+	unsigned int s_cluster_ratio;	/* Number of blocks per cluster */
+	unsigned int s_cluster_bits;	/* log2 of s_cluster_ratio */
 	loff_t s_bitmap_maxbytes;	/* max bytes for bitmap files */
 	struct buffer_head * s_sbh;	/* Buffer containing the super block */
 	struct ext4_super_block *s_es;	/* Pointer to the super block in the buffer */
@@ -1338,6 +1349,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
 #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_BIGALLOC		0x0200
 
 #define EXT4_FEATURE_INCOMPAT_COMPRESSION	0x0001
 #define EXT4_FEATURE_INCOMPAT_FILETYPE		0x0002
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index cb22783..3f82b79 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1908,7 +1908,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
 		res = MS_RDONLY;
 	}
 	if (read_only)
-		return res;
+		goto done;
 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
 			 "running e2fsck is recommended");
@@ -1939,6 +1939,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
 
 	ext4_commit_super(sb, 1);
+done:
 	if (test_opt(sb, DEBUG))
 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
@@ -3061,10 +3062,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	char *cp;
 	const char *descr;
 	int ret = -ENOMEM;
-	int blocksize;
+	int blocksize, clustersize;
 	unsigned int db_count;
 	unsigned int i;
-	int needs_recovery, has_huge_files;
+	int needs_recovery, has_huge_files, has_bigalloc;
 	__u64 blocks_count;
 	int err;
 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
@@ -3337,12 +3338,53 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		sb->s_dirt = 1;
 	}
 
-	if (sbi->s_blocks_per_group > blocksize * 8) {
-		ext4_msg(sb, KERN_ERR,
-		       "#blocks per group too big: %lu",
-		       sbi->s_blocks_per_group);
-		goto failed_mount;
+	/* Handle clustersize */
+	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
+	has_bigalloc = EXT4_HAS_RO_COMPAT_FEATURE(sb,
+				EXT4_FEATURE_RO_COMPAT_BIGALLOC);
+	if (has_bigalloc) {
+		if (clustersize < blocksize) {
+			ext4_msg(sb, KERN_ERR,
+				 "cluster size (%d) smaller than "
+				 "block size (%d)", clustersize, blocksize);
+			goto failed_mount;
+		}
+		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
+			le32_to_cpu(es->s_log_block_size);
+		sbi->s_clusters_per_group =
+			le32_to_cpu(es->s_clusters_per_group);
+		if (sbi->s_clusters_per_group > blocksize * 8) {
+			ext4_msg(sb, KERN_ERR,
+				 "#clusters per group too big: %lu",
+				 sbi->s_clusters_per_group);
+			goto failed_mount;
+		}
+		if (sbi->s_blocks_per_group !=
+		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
+			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
+				 "clusters per group (%lu) inconsistent",
+				 sbi->s_blocks_per_group,
+				 sbi->s_clusters_per_group);
+			goto failed_mount;
+		}
+	} else {
+		if (clustersize != blocksize) {
+			ext4_warning(sb, "fragment/cluster size (%d) != "
+				     "block size (%d)", clustersize,
+				     blocksize);
+			clustersize = blocksize;
+		}
+		if (sbi->s_blocks_per_group > blocksize * 8) {
+			ext4_msg(sb, KERN_ERR,
+				 "#blocks per group too big: %lu",
+				 sbi->s_blocks_per_group);
+			goto failed_mount;
+		}
+		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
+		sbi->s_cluster_bits = 0;
 	}
+	sbi->s_cluster_ratio = clustersize / blocksize;
+
 	if (sbi->s_inodes_per_group > blocksize * 8) {
 		ext4_msg(sb, KERN_ERR,
 		       "#inodes per group too big: %lu",
