diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index a27d57ea301c..e05898c9acbc 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -54,18 +54,16 @@ xfs_bmap_compute_maxlevels(
 	int		whichfork)	/* data or attr fork */
 {
 	xfs_extnum_t	maxleafents;	/* max leaf entries possible */
+	uint64_t	maxblocks;	/* max blocks at this level */
 	int		level;		/* btree level */
-	uint		maxblocks;	/* max blocks at this level */
 	int		maxrootrecs;	/* max records in root block */
 	int		minleafrecs;	/* min records in leaf block */
 	int		minnoderecs;	/* min records in node block */
 	int		sz;		/* root block size */
 
 	/*
-	 * The maximum number of extents in a file, hence the maximum number of
-	 * leaf entries, is controlled by the size of the on-disk extent count,
-	 * either a signed 32-bit number for the data fork, or a signed 16-bit
-	 * number for the attr fork.
+	 * The maximum number of extents in a fork, hence the maximum number of
+	 * leaf entries, is controlled by the size of the on-disk extent count.
 	 *
 	 * Note that we can no longer assume that if we are in ATTR1 that the
 	 * fork offset of all the inodes will be
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 2362cc005cc6..3aa83d75670d 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -485,13 +485,15 @@ xfs_sb_has_ro_compat_feature(
 #define XFS_SB_FEAT_INCOMPAT_BIGTIME	(1 << 3)	/* large timestamps */
 #define XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR (1 << 4)	/* needs xfs_repair */
 #define XFS_SB_FEAT_INCOMPAT_METADIR	(1 << 5)	/* metadata dir tree */
-#define XFS_SB_FEAT_INCOMPAT_ALL \
+#define XFS_SB_FEAT_INCOMPAT_EXTCOUNT_64BIT (1 << 6)	/* 64-bit inode fork extent counter */
+#define XFS_SB_FEAT_INCOMPAT_ALL		\
 		(XFS_SB_FEAT_INCOMPAT_FTYPE|	\
 		 XFS_SB_FEAT_INCOMPAT_SPINODES|	\
 		 XFS_SB_FEAT_INCOMPAT_META_UUID| \
 		 XFS_SB_FEAT_INCOMPAT_BIGTIME| \
 		 XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR| \
-		 XFS_SB_FEAT_INCOMPAT_METADIR)
+		 XFS_SB_FEAT_INCOMPAT_METADIR| \
+		 XFS_SB_FEAT_INCOMPAT_EXTCOUNT_64BIT)
 
 #define XFS_SB_FEAT_INCOMPAT_UNKNOWN	~XFS_SB_FEAT_INCOMPAT_ALL
 static inline bool
@@ -591,6 +593,12 @@ static inline bool xfs_sb_version_hasmetauuid(struct xfs_sb *sbp)
 		(sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_META_UUID);
 }
 
+static inline bool xfs_sb_version_hasextcount_64bit(struct xfs_sb *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) &&
+		(sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_EXTCOUNT_64BIT);
+}
+
 static inline bool xfs_sb_version_hasrmapbt(struct xfs_sb *sbp)
 {
 	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) &&
@@ -1039,6 +1047,16 @@ typedef struct xfs_dinode {
 	__be64		di_size;	/* number of bytes in file */
 	__be64		di_nblocks;	/* # of direct & btree blocks used */
 	__be32		di_extsize;	/* basic/minimum extent size for file */
+
+	/*
+	 * On a extcnt64bit filesystem, di_nextents64 holds the data fork
+	 * extent count, di_nextents32 holds the attr fork extent count,
+	 * and di_nextents16 must be zero.
+	 *
+	 * Otherwise, di_nextents32 holds the data fork extent count,
+	 * di_nextents16 holds the attr fork extent count, and di_nextents64
+	 * must be zero.
+	 */
 	__be32		di_nextents32;	/* number of extents in data fork */
 	__be16		di_nextents16;	/* number of extents in attribute fork*/
 	__u8		di_forkoff;	/* attr fork offs, <<3 for 64b align */
@@ -1057,7 +1075,8 @@ typedef struct xfs_dinode {
 	__be64		di_lsn;		/* flush sequence */
 	__be64		di_flags2;	/* more random flags */
 	__be32		di_cowextsize;	/* basic cow extent size for file */
-	__u8		di_pad2[12];	/* more padding for future expansion */
+	__u8		di_pad2[4];	/* more padding for future expansion */
+	__be64		di_nextents64;
 
 	/* fields only written to during inode creation */
 	xfs_timestamp_t	di_crtime;	/* time created */
@@ -1113,6 +1132,8 @@ enum xfs_dinode_fmt {
  * Max values for extlen and disk inode's extent counters.
  */
 #define	MAXEXTLEN		((uint32_t)0x1fffff) /* 21 bits */
+#define XFS_IFORK_EXTCNT_MAXU48	((uint64_t)0xffffffffffff) /* Unsigned 48-bits */
+#define XFS_IFORK_EXTCNT_MAXU32	((uint32_t)0xffffffff)	/* Unsigned 32-bits */
 #define XFS_IFORK_EXTCNT_MAXS32 ((int32_t)0x7fffffff)  /* Signed 32-bits */
 #define XFS_IFORK_EXTCNT_MAXS16 ((int16_t)0x7fff)      /* Signed 16-bits */
 
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 756be4ff5996..57f67445f095 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -858,6 +858,7 @@ struct xfs_scrub_metadata {
 #define XFS_IOC_BULKSTAT_V5	     _IOR ('X', 127, struct xfs_bulkstat_req)
 #define XFS_IOC_INUMBERS	     _IOR ('X', 128, struct xfs_inumbers_req)
 /*	FIEXCHANGE_RANGE ----------- hoisted 129	 */
+#define XFS_IOC_BULKSTAT_V6	     _IOR ('X', 130, struct xfs_bulkstat_req)
 /*	XFS_IOC_GETFSUUID ---------- deprecated 140	 */
 
 
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 65d753e16007..28e49394edbb 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -291,6 +291,7 @@ xfs_inode_to_disk(
 	struct xfs_dinode	*to,
 	xfs_lsn_t		lsn)
 {
+	struct xfs_sb		*sbp = &ip->i_mount->m_sb;
 	struct inode		*inode = VFS_I(ip);
 
 	to->di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
@@ -313,8 +314,6 @@ xfs_inode_to_disk(
 	to->di_size = cpu_to_be64(ip->i_disk_size);
 	to->di_nblocks = cpu_to_be64(ip->i_nblocks);
 	to->di_extsize = cpu_to_be32(ip->i_extsize);
-	to->di_nextents32 = cpu_to_be32(xfs_ifork_nextents(&ip->i_df));
-	to->di_nextents16 = cpu_to_be16(xfs_ifork_nextents(ip->i_afp));
 	to->di_forkoff = ip->i_forkoff;
 	to->di_aformat = xfs_ifork_format(ip->i_afp);
 	to->di_flags = cpu_to_be16(ip->i_diflags);
@@ -334,6 +333,19 @@ xfs_inode_to_disk(
 		to->di_version = 2;
 		to->di_flushiter = cpu_to_be16(ip->i_flushiter);
 	}
+
+	if (xfs_sb_version_hasextcount_64bit(sbp)) {
+		to->di_nextents64 = cpu_to_be64(xfs_ifork_nextents(&ip->i_df));
+		to->di_nextents32 = cpu_to_be32(xfs_ifork_nextents(ip->i_afp));
+		/*
+		 * xchk_dinode() passes an uninitialized disk inode. Hence,
+		 * clear di_nextents16 field explicitly.
+		 */
+		to->di_nextents16 = cpu_to_be16(0);
+	} else {
+		to->di_nextents32 = cpu_to_be32(xfs_ifork_nextents(&ip->i_df));
+		to->di_nextents16 = cpu_to_be16(xfs_ifork_nextents(ip->i_afp));
+	}
 }
 
 static xfs_failaddr_t
@@ -386,14 +398,22 @@ xfs_dfork_nextents(
 	xfs_extnum_t		*nextents)
 {
 	int			error = 0;
+	bool			has_64bit_extcnt;
+
+	has_64bit_extcnt = xfs_sb_version_hasextcount_64bit(&mp->m_sb);
+
+	if (has_64bit_extcnt && dip->di_nextents16 != 0)
+		return -EFSCORRUPTED;
 
 	switch (whichfork) {
 	case XFS_DATA_FORK:
-		*nextents = be32_to_cpu(dip->di_nextents32);
+		*nextents = has_64bit_extcnt ? be64_to_cpu(dip->di_nextents64)
+			: be32_to_cpu(dip->di_nextents32);
 		break;
 
 	case XFS_ATTR_FORK:
-		*nextents = be16_to_cpu(dip->di_nextents16);
+		*nextents = has_64bit_extcnt ? be32_to_cpu(dip->di_nextents32)
+			: be16_to_cpu(dip->di_nextents16);
 		break;
 
 	default:
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index 1eda2163603e..ffdd2abcd73c 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -21,9 +21,9 @@ struct xfs_ifork {
 		void		*if_root;	/* extent tree root */
 		char		*if_data;	/* inline file data */
 	} if_u1;
+	xfs_extnum_t		if_nextents;	/* # of extents in this fork */
 	short			if_broot_bytes;	/* bytes allocated for root */
 	int8_t			if_format;	/* format of this fork */
-	xfs_extnum_t		if_nextents;	/* # of extents in this fork */
 };
 
 /*
@@ -135,10 +135,22 @@ static inline int8_t xfs_ifork_format(struct xfs_ifork *ifp)
 
 static inline xfs_extnum_t xfs_iext_max(struct xfs_mount *mp, int whichfork)
 {
-	if (whichfork == XFS_DATA_FORK || whichfork == XFS_COW_FORK)
-		return XFS_IFORK_EXTCNT_MAXS32;
-	else
-		return XFS_IFORK_EXTCNT_MAXS16;
+	bool has_64bit_extcnt = xfs_sb_version_hasextcount_64bit(&mp->m_sb);
+
+	switch (whichfork) {
+	case XFS_DATA_FORK:
+	case XFS_COW_FORK:
+		return has_64bit_extcnt ? XFS_IFORK_EXTCNT_MAXU48
+			: XFS_IFORK_EXTCNT_MAXS32;
+
+	case XFS_ATTR_FORK:
+		return has_64bit_extcnt ? XFS_IFORK_EXTCNT_MAXU32
+			: XFS_IFORK_EXTCNT_MAXS16;
+
+	default:
+		ASSERT(0);
+		return 0;
+	}
 }
 
 struct xfs_ifork *xfs_ifork_alloc(enum xfs_dinode_fmt format,
diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index ca8e4ad8312a..9b5d64708ed1 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -420,7 +420,8 @@ struct xfs_log_dinode {
 	xfs_lsn_t	di_lsn;		/* flush sequence */
 	uint64_t	di_flags2;	/* more random flags */
 	uint32_t	di_cowextsize;	/* basic cow extent size for file */
-	uint8_t		di_pad2[12];	/* more padding for future expansion */
+	uint8_t		di_pad2[4];	/* more padding for future expansion */
+	uint64_t	di_nextents64; /* higher part of data fork extent count */
 
 	/* fields only written to during inode creation */
 	xfs_log_timestamp_t di_crtime;	/* time created */
diff --git a/fs/xfs/scrub/inode_repair.c b/fs/xfs/scrub/inode_repair.c
index 4d773a16f886..dde6b700e891 100644
--- a/fs/xfs/scrub/inode_repair.c
+++ b/fs/xfs/scrub/inode_repair.c
@@ -736,7 +736,10 @@ xrep_dinode_zap_dfork(
 {
 	trace_xrep_dinode_zap_dfork(sc, dip);
 
-	dip->di_nextents32 = 0;
+	if (xfs_sb_version_hasextcount_64bit(&sc->mp->m_sb))
+		dip->di_nextents64 = 0;
+	else
+		dip->di_nextents32 = 0;
 
 	/* Special files always get reset to DEV */
 	switch (mode & S_IFMT) {
@@ -823,7 +826,11 @@ xrep_dinode_zap_afork(
 	trace_xrep_dinode_zap_afork(sc, dip);
 
 	dip->di_aformat = XFS_DINODE_FMT_EXTENTS;
-	dip->di_nextents16 = 0;
+
+	if (xfs_sb_version_hasextcount_64bit(&sc->mp->m_sb))
+		dip->di_nextents32 = 0;
+	else
+		dip->di_nextents16 = 0;
 
 	dip->di_forkoff = 0;
 	dip->di_mode = cpu_to_be16(mode & ~0777);
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 4070fb01350c..19d525093702 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2511,7 +2511,7 @@ xfs_iflush(
 				ip->i_nblocks, mp, XFS_ERRTAG_IFLUSH_5)) {
 		xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
 			"%s: detected corrupt incore inode %llu, "
-			"total extents = %llu nblocks = %lld, ptr "PTR_FMT,
+			"total extents = %llu, nblocks = %lld, ptr "PTR_FMT,
 			__func__, ip->i_ino,
 			ip->i_df.if_nextents + xfs_ifork_nextents(ip->i_afp),
 			ip->i_nblocks, ip);
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index f54ce7468ba1..3fa73100484b 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -364,6 +364,7 @@ xfs_inode_to_log_dinode(
 	struct xfs_log_dinode	*to,
 	xfs_lsn_t		lsn)
 {
+	struct xfs_sb		*sbp = &ip->i_mount->m_sb;
 	struct inode		*inode = VFS_I(ip);
 
 	to->di_magic = XFS_DINODE_MAGIC;
@@ -385,8 +386,6 @@ xfs_inode_to_log_dinode(
 	to->di_size = ip->i_disk_size;
 	to->di_nblocks = ip->i_nblocks;
 	to->di_extsize = ip->i_extsize;
-	to->di_nextents32 = xfs_ifork_nextents(&ip->i_df);
-	to->di_nextents16 = xfs_ifork_nextents(ip->i_afp);
 	to->di_forkoff = ip->i_forkoff;
 	to->di_aformat = xfs_ifork_format(ip->i_afp);
 	to->di_flags = ip->i_diflags;
@@ -402,6 +401,16 @@ xfs_inode_to_log_dinode(
 		to->di_crtime = xfs_inode_to_log_dinode_ts(ip, ip->i_crtime);
 		to->di_flags2 = ip->i_diflags2;
 		to->di_cowextsize = ip->i_cowextsize;
+		if (xfs_sb_version_hasextcount_64bit(sbp)) {
+			to->di_nextents64 = xfs_ifork_nextents(&ip->i_df);
+			to->di_nextents32 = xfs_ifork_nextents(ip->i_afp);
+			to->di_nextents16 = 0;
+		} else {
+			to->di_nextents64 = 0;
+			to->di_nextents32 = xfs_ifork_nextents(&ip->i_df);
+			to->di_nextents16 = xfs_ifork_nextents(ip->i_afp);
+		}
+
 		to->di_ino = ip->i_ino;
 		to->di_lsn = lsn;
 		memset(to->di_pad2, 0, sizeof(to->di_pad2));
@@ -410,6 +419,8 @@ xfs_inode_to_log_dinode(
 	} else {
 		to->di_version = 2;
 		to->di_flushiter = ip->i_flushiter;
+		to->di_nextents32 = xfs_ifork_nextents(&ip->i_df);
+		to->di_nextents16 = xfs_ifork_nextents(ip->i_afp);
 	}
 }
 
diff --git a/fs/xfs/xfs_inode_item_recover.c b/fs/xfs/xfs_inode_item_recover.c
index 40af9d1265c7..fcf360c03bc1 100644
--- a/fs/xfs/xfs_inode_item_recover.c
+++ b/fs/xfs/xfs_inode_item_recover.c
@@ -166,8 +166,6 @@ xfs_log_dinode_to_disk(
 	to->di_size = cpu_to_be64(from->di_size);
 	to->di_nblocks = cpu_to_be64(from->di_nblocks);
 	to->di_extsize = cpu_to_be32(from->di_extsize);
-	to->di_nextents32 = cpu_to_be32(from->di_nextents32);
-	to->di_nextents16 = cpu_to_be16(from->di_nextents16);
 	to->di_forkoff = from->di_forkoff;
 	to->di_aformat = from->di_aformat;
 	to->di_dmevmask = cpu_to_be32(from->di_dmevmask);
@@ -181,12 +179,17 @@ xfs_log_dinode_to_disk(
 							  from->di_crtime);
 		to->di_flags2 = cpu_to_be64(from->di_flags2);
 		to->di_cowextsize = cpu_to_be32(from->di_cowextsize);
+		to->di_nextents64 = cpu_to_be64(from->di_nextents64);
+		to->di_nextents32 = cpu_to_be32(from->di_nextents32);
+		to->di_nextents16 = cpu_to_be16(from->di_nextents16);
 		to->di_ino = cpu_to_be64(from->di_ino);
 		to->di_lsn = cpu_to_be64(from->di_lsn);
 		memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2));
 		uuid_copy(&to->di_uuid, &from->di_uuid);
 		to->di_flushiter = 0;
 	} else {
+		to->di_nextents32 = cpu_to_be32(from->di_nextents32);
+		to->di_nextents16 = cpu_to_be16(from->di_nextents16);
 		to->di_flushiter = cpu_to_be16(from->di_flushiter);
 	}
 }
@@ -202,6 +205,8 @@ xlog_recover_inode_commit_pass2(
 	struct xfs_mount		*mp = log->l_mp;
 	struct xfs_buf			*bp;
 	struct xfs_dinode		*dip;
+	xfs_extnum_t                    nextents;
+	xfs_aextnum_t                   anextents;
 	int				len;
 	char				*src;
 	char				*dest;
@@ -332,16 +337,24 @@ xlog_recover_inode_commit_pass2(
 			goto out_release;
 		}
 	}
-	if (unlikely(ldip->di_nextents32 + ldip->di_nextents16 > ldip->di_nblocks)) {
+
+	if (xfs_sb_version_hasextcount_64bit(&mp->m_sb)) {
+		nextents = ldip->di_nextents64;
+		anextents = ldip->di_nextents32;
+	} else {
+		nextents = ldip->di_nextents32;
+		anextents = ldip->di_nextents16;
+	}
+
+	if (unlikely(nextents + anextents > ldip->di_nblocks)) {
 		XFS_CORRUPTION_ERROR("xlog_recover_inode_pass2(5)",
 				     XFS_ERRLEVEL_LOW, mp, ldip,
 				     sizeof(*ldip));
 		xfs_alert(mp,
 	"%s: Bad inode log record, rec ptr "PTR_FMT", dino ptr "PTR_FMT", "
-	"dino bp "PTR_FMT", ino %Ld, total extents = %d, nblocks = %Ld",
+	"dino bp "PTR_FMT", ino %Ld, total extents = %llu, nblocks = %Ld",
 			__func__, item, dip, bp, in_f->ilf_ino,
-			ldip->di_nextents32 + ldip->di_nextents16,
-			ldip->di_nblocks);
+			nextents + anextents, ldip->di_nblocks);
 		error = -EFSCORRUPTED;
 		goto out_release;
 	}
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 19964b394dc4..2d44aa655f41 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1901,6 +1901,9 @@ xfs_file_ioctl(
 	case XFS_IOC_BULKSTAT_V5:
 		return xfs_ioc_bulkstat(filp, cmd, arg,
 				XFS_BULKSTAT_VERSION_V5);
+	case XFS_IOC_BULKSTAT_V6:
+		return xfs_ioc_bulkstat(filp, cmd, arg,
+				XFS_BULKSTAT_VERSION_V6);
 	case XFS_IOC_INUMBERS:
 		return xfs_ioc_inumbers(mp, cmd, arg,
 				XFS_INUMBERS_VERSION_V5);
