[11/14] xfs: widen ondisk timestamps to deal with y2038 problem
diff mbox series

Message ID 157784113220.1364230.3763399684650880969.stgit@magnolia
State New
Headers show
Series
  • xfs: widen timestamps to deal with y2038
Related show

Commit Message

Darrick J. Wong Jan. 1, 2020, 1:12 a.m. UTC
From: Darrick J. Wong <darrick.wong@oracle.com>

Redesign the ondisk timestamps to be a simple unsigned 64-bit counter of
nanoseconds since 14 Dec 1901 (i.e. the minimum time in the 32-bit unix
time epoch).  This enables us to handle dates up to 2486, which solves
the y2038 problem.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_format.h     |   38 +++++++++++++++++++++++++++-
 fs/xfs/libxfs/xfs_fs.h         |    1 +
 fs/xfs/libxfs/xfs_inode_buf.c  |   55 +++++++++++++++++++++++++++++++++-------
 fs/xfs/libxfs/xfs_inode_buf.h  |    8 +++---
 fs/xfs/libxfs/xfs_log_format.h |    3 ++
 fs/xfs/libxfs/xfs_sb.c         |    2 +
 fs/xfs/scrub/inode.c           |   16 ++++++++----
 fs/xfs/scrub/inode_repair.c    |    2 +
 fs/xfs/xfs_inode.c             |   19 +++++++++-----
 fs/xfs/xfs_inode_item.c        |   36 ++++++++++++++++++++------
 fs/xfs/xfs_ioctl.c             |    3 +-
 fs/xfs/xfs_ondisk.h            |    3 ++
 fs/xfs/xfs_super.c             |   13 ++++++++-
 13 files changed, 163 insertions(+), 36 deletions(-)

Comments

Amir Goldstein May 31, 2020, 12:30 p.m. UTC | #1
> @@ -265,17 +278,35 @@ xfs_inode_from_disk(
>         if (to->di_version == 3) {
>                 inode_set_iversion_queried(inode,
>                                            be64_to_cpu(from->di_changecount));
> -               xfs_inode_from_disk_timestamp(&to->di_crtime, &from->di_crtime);
> +               xfs_inode_from_disk_timestamp(from, &to->di_crtime,
> +                               &from->di_crtime);
>                 to->di_flags2 = be64_to_cpu(from->di_flags2);
>                 to->di_cowextsize = be32_to_cpu(from->di_cowextsize);
> +               /*
> +                * Convert this inode's timestamps to bigtime format the next
> +                * time we write it out to disk.
> +                */
> +               if (xfs_sb_version_hasbigtime(&mp->m_sb))
> +                       to->di_flags2 |= XFS_DIFLAG2_BIGTIME;
>         }

This feels wrong.
incore inode has a union for timestamp.
This flag should indicate how the union should be interpreted
otherwise it is going to be very easy to stumble on that in future code.

So either convert incore timestamp now or check hasbigtime when
we write to disk.

Thanks,
Amir.

Patch
diff mbox series

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 8a1bb33ebdd5..9b127e4f4077 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -467,6 +467,7 @@  xfs_sb_has_ro_compat_feature(
 #define XFS_SB_FEAT_INCOMPAT_FTYPE	(1 << 0)	/* filetype in dirent */
 #define XFS_SB_FEAT_INCOMPAT_SPINODES	(1 << 1)	/* sparse inode chunks */
 #define XFS_SB_FEAT_INCOMPAT_META_UUID	(1 << 2)	/* metadata UUID */
+#define XFS_SB_FEAT_INCOMPAT_BIGTIME	(1 << 3)	/* large timestamps */
 #define XFS_SB_FEAT_INCOMPAT_ALL \
 		(XFS_SB_FEAT_INCOMPAT_FTYPE|	\
 		 XFS_SB_FEAT_INCOMPAT_SPINODES|	\
@@ -548,6 +549,12 @@  static inline bool xfs_sb_version_hasreflink(struct xfs_sb *sbp)
 		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_REFLINK);
 }
 
+static inline bool xfs_sb_version_hasbigtime(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
+		(sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_BIGTIME);
+}
+
 /*
  * Inode btree block counter.  We record the number of inobt and finobt blocks
  * in the AGI header so that we can skip the finobt walk at mount time when
@@ -847,12 +854,18 @@  typedef struct xfs_agfl {
  *
  * Inode timestamps consist of signed 32-bit counters for seconds and
  * nanoseconds; time zero is the Unix epoch, Jan  1 00:00:00 UTC 1970.
+ *
+ * When bigtime is enabled, timestamps become an unsigned 64-bit nanoseconds
+ * counter.  Time zero is the start of the classic timestamp range.
  */
 union xfs_timestamp {
 	struct {
 		__be32		t_sec;		/* timestamp seconds */
 		__be32		t_nsec;		/* timestamp nanoseconds */
 	};
+
+	/* Nanoseconds since the bigtime epoch. */
+	__be64			t_bigtime;
 };
 
 /*
@@ -867,6 +880,25 @@  union xfs_timestamp {
  */
 #define XFS_INO_TIME_MAX	((int64_t)S32_MAX)
 
+/*
+ * Number of seconds between the start of the bigtime timestamp range and the
+ * start of the Unix epoch.
+ */
+#define XFS_INO_BIGTIME_EPOCH	(-XFS_INO_TIME_MIN)
+
+/*
+ * Smallest possible timestamp with big timestamps, which is
+ * Dec 13 20:45:52 UTC 1901.
+ */
+#define XFS_INO_BIGTIME_MIN	(XFS_INO_TIME_MIN)
+
+/*
+ * Largest possible timestamp with big timestamps, which is
+ * Jul  2 20:20:25 UTC 2486.
+ */
+#define XFS_INO_BIGTIME_MAX	((int64_t)((-1ULL / NSEC_PER_SEC) - \
+					   XFS_INO_BIGTIME_EPOCH))
+
 /*
  * On-disk inode structure.
  *
@@ -1094,12 +1126,16 @@  static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
 #define XFS_DIFLAG2_DAX_BIT	0	/* use DAX for this inode */
 #define XFS_DIFLAG2_REFLINK_BIT	1	/* file's blocks may be shared */
 #define XFS_DIFLAG2_COWEXTSIZE_BIT   2  /* copy on write extent size hint */
+#define XFS_DIFLAG2_BIGTIME_BIT	3	/* big timestamps */
+
 #define XFS_DIFLAG2_DAX		(1 << XFS_DIFLAG2_DAX_BIT)
 #define XFS_DIFLAG2_REFLINK     (1 << XFS_DIFLAG2_REFLINK_BIT)
 #define XFS_DIFLAG2_COWEXTSIZE  (1 << XFS_DIFLAG2_COWEXTSIZE_BIT)
+#define XFS_DIFLAG2_BIGTIME	(1 << XFS_DIFLAG2_BIGTIME_BIT)
 
 #define XFS_DIFLAG2_ANY \
-	(XFS_DIFLAG2_DAX | XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE)
+	(XFS_DIFLAG2_DAX | XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE | \
+	 XFS_DIFLAG2_BIGTIME)
 
 /*
  * Inode number format:
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 40bdea01eff4..86fd287017ca 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -249,6 +249,7 @@  typedef struct xfs_fsop_resblks {
 #define XFS_FSOP_GEOM_FLAGS_SPINODES	(1 << 18) /* sparse inode chunks   */
 #define XFS_FSOP_GEOM_FLAGS_RMAPBT	(1 << 19) /* reverse mapping btree */
 #define XFS_FSOP_GEOM_FLAGS_REFLINK	(1 << 20) /* files can share blocks */
+#define XFS_FSOP_GEOM_FLAGS_BIGTIME	(1 << 21) /* 64-bit nsec timestamps */
 
 /*
  * Minimum and maximum sizes need for growth checks.
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index f4725e4916ab..d0084f47f246 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -203,9 +203,22 @@  xfs_imap_to_bp(
 
 void
 xfs_inode_from_disk_timestamp(
+	struct xfs_dinode		*dip,
 	struct timespec64		*tv,
 	const union xfs_timestamp	*ts)
 {
+	if (dip->di_version >= 3 &&
+	    (dip->di_flags2 & cpu_to_be64(XFS_DIFLAG2_BIGTIME))) {
+		uint64_t		t = be64_to_cpu(ts->t_bigtime);
+		uint64_t		s;
+		uint32_t		n;
+
+		s = div_u64_rem(t, NSEC_PER_SEC, &n);
+		tv->tv_sec = s - XFS_INO_BIGTIME_EPOCH;
+		tv->tv_nsec = n;
+		return;
+	}
+
 	tv->tv_sec = (int)be32_to_cpu(ts->t_sec);
 	tv->tv_nsec = (int)be32_to_cpu(ts->t_nsec);
 }
@@ -217,7 +230,7 @@  xfs_inode_from_disk(
 {
 	struct xfs_icdinode	*to = &ip->i_d;
 	struct inode		*inode = VFS_I(ip);
-
+	struct xfs_mount	*mp = ip->i_mount;
 
 	/*
 	 * Convert v1 inodes immediately to v2 inode format as this is the
@@ -245,9 +258,9 @@  xfs_inode_from_disk(
 	 * a time before epoch is converted to a time long after epoch
 	 * on 64 bit systems.
 	 */
-	xfs_inode_from_disk_timestamp(&inode->i_atime, &from->di_atime);
-	xfs_inode_from_disk_timestamp(&inode->i_mtime, &from->di_mtime);
-	xfs_inode_from_disk_timestamp(&inode->i_ctime, &from->di_ctime);
+	xfs_inode_from_disk_timestamp(from, &inode->i_atime, &from->di_atime);
+	xfs_inode_from_disk_timestamp(from, &inode->i_mtime, &from->di_mtime);
+	xfs_inode_from_disk_timestamp(from, &inode->i_ctime, &from->di_ctime);
 	inode->i_generation = be32_to_cpu(from->di_gen);
 	inode->i_mode = be16_to_cpu(from->di_mode);
 
@@ -265,17 +278,35 @@  xfs_inode_from_disk(
 	if (to->di_version == 3) {
 		inode_set_iversion_queried(inode,
 					   be64_to_cpu(from->di_changecount));
-		xfs_inode_from_disk_timestamp(&to->di_crtime, &from->di_crtime);
+		xfs_inode_from_disk_timestamp(from, &to->di_crtime,
+				&from->di_crtime);
 		to->di_flags2 = be64_to_cpu(from->di_flags2);
 		to->di_cowextsize = be32_to_cpu(from->di_cowextsize);
+		/*
+		 * Convert this inode's timestamps to bigtime format the next
+		 * time we write it out to disk.
+		 */
+		if (xfs_sb_version_hasbigtime(&mp->m_sb))
+			to->di_flags2 |= XFS_DIFLAG2_BIGTIME;
 	}
 }
 
 void
 xfs_inode_to_disk_timestamp(
+	struct xfs_icdinode		*from,
 	union xfs_timestamp		*ts,
 	const struct timespec64		*tv)
 {
+	if (from->di_version >= 3 &&
+	    (from->di_flags2 & XFS_DIFLAG2_BIGTIME)) {
+		uint64_t		t;
+
+		t = (uint64_t)(tv->tv_sec + XFS_INO_BIGTIME_EPOCH);
+		t *= NSEC_PER_SEC;
+		ts->t_bigtime = cpu_to_be64(t + tv->tv_nsec);
+		return;
+	}
+
 	ts->t_sec = cpu_to_be32(tv->tv_sec);
 	ts->t_nsec = cpu_to_be32(tv->tv_nsec);
 }
@@ -300,9 +331,9 @@  xfs_inode_to_disk(
 	to->di_projid_hi = cpu_to_be16(from->di_projid >> 16);
 
 	memset(to->di_pad, 0, sizeof(to->di_pad));
-	xfs_inode_to_disk_timestamp(&to->di_atime, &inode->i_atime);
-	xfs_inode_to_disk_timestamp(&to->di_mtime, &inode->i_mtime);
-	xfs_inode_to_disk_timestamp(&to->di_ctime, &inode->i_ctime);
+	xfs_inode_to_disk_timestamp(from, &to->di_atime, &inode->i_atime);
+	xfs_inode_to_disk_timestamp(from, &to->di_mtime, &inode->i_mtime);
+	xfs_inode_to_disk_timestamp(from, &to->di_ctime, &inode->i_ctime);
 	to->di_nlink = cpu_to_be32(inode->i_nlink);
 	to->di_gen = cpu_to_be32(inode->i_generation);
 	to->di_mode = cpu_to_be16(inode->i_mode);
@@ -320,7 +351,8 @@  xfs_inode_to_disk(
 
 	if (from->di_version == 3) {
 		to->di_changecount = cpu_to_be64(inode_peek_iversion(inode));
-		xfs_inode_to_disk_timestamp(&to->di_crtime, &from->di_crtime);
+		xfs_inode_to_disk_timestamp(from, &to->di_crtime,
+				&from->di_crtime);
 		to->di_flags2 = cpu_to_be64(from->di_flags2);
 		to->di_cowextsize = cpu_to_be32(from->di_cowextsize);
 		to->di_ino = cpu_to_be64(ip->i_ino);
@@ -539,6 +571,11 @@  xfs_dinode_verify(
 	if (fa)
 		return fa;
 
+	/* bigtime iflag can only happen on bigtime filesystems */
+	if ((flags2 & (XFS_DIFLAG2_BIGTIME)) &&
+	    !xfs_sb_version_hasbigtime(&mp->m_sb))
+		return __this_address;
+
 	return NULL;
 }
 
diff --git a/fs/xfs/libxfs/xfs_inode_buf.h b/fs/xfs/libxfs/xfs_inode_buf.h
index 787a50df232f..ea6818b7175f 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.h
+++ b/fs/xfs/libxfs/xfs_inode_buf.h
@@ -75,9 +75,9 @@  xfs_failaddr_t xfs_inode_validate_cowextsize(struct xfs_mount *mp,
 		uint32_t cowextsize, uint16_t mode, uint16_t flags,
 		uint64_t flags2);
 
-void xfs_inode_from_disk_timestamp(struct timespec64 *tv,
-		const union xfs_timestamp *ts);
-void xfs_inode_to_disk_timestamp(union xfs_timestamp *ts,
-		const struct timespec64 *tv);
+void xfs_inode_from_disk_timestamp(struct xfs_dinode *dip,
+		struct timespec64 *tv, const union xfs_timestamp *ts);
+void xfs_inode_to_disk_timestamp(struct xfs_icdinode *from,
+		union xfs_timestamp *ts, const struct timespec64 *tv);
 
 #endif	/* __XFS_INODE_BUF_H__ */
diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index c98060115352..17789cf130e3 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -373,6 +373,9 @@  union xfs_ictimestamp {
 		int32_t		t_sec;		/* timestamp seconds */
 		int32_t		t_nsec;		/* timestamp nanoseconds */
 	};
+
+	/* Nanoseconds since the bigtime epoch. */
+	uint64_t		t_bigtime;
 };
 
 /*
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 4a923545465d..4e5b27a4b4b4 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -1133,6 +1133,8 @@  xfs_fs_geometry(
 		geo->flags |= XFS_FSOP_GEOM_FLAGS_RMAPBT;
 	if (xfs_sb_version_hasreflink(sbp))
 		geo->flags |= XFS_FSOP_GEOM_FLAGS_REFLINK;
+	if (xfs_sb_version_hasbigtime(sbp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_BIGTIME;
 	if (xfs_sb_version_hassector(sbp))
 		geo->logsectsize = sbp->sb_logsectsize;
 	else
diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c
index 9f036053fdb7..b354825f4e51 100644
--- a/fs/xfs/scrub/inode.c
+++ b/fs/xfs/scrub/inode.c
@@ -190,6 +190,11 @@  xchk_inode_flags2(
 	if ((flags2 & XFS_DIFLAG2_DAX) && (flags2 & XFS_DIFLAG2_REFLINK))
 		goto bad;
 
+	/* the incore bigtime iflag always follows the feature flag */
+	if (!!xfs_sb_version_hasbigtime(&mp->m_sb) ^
+	    !!(flags2 & XFS_DIFLAG2_BIGTIME))
+		goto bad;
+
 	return;
 bad:
 	xchk_ino_set_corrupt(sc, ino);
@@ -199,11 +204,12 @@  static inline void
 xchk_dinode_nsec(
 	struct xfs_scrub		*sc,
 	xfs_ino_t			ino,
+	struct xfs_dinode		*dip,
 	const union xfs_timestamp	*ts)
 {
 	struct timespec64		tv;
 
-	xfs_inode_from_disk_timestamp(&tv, ts);
+	xfs_inode_from_disk_timestamp(dip, &tv, ts);
 	if (tv.tv_nsec < 0 || tv.tv_nsec >= NSEC_PER_SEC)
 		xchk_ino_set_corrupt(sc, ino);
 }
@@ -306,9 +312,9 @@  xchk_dinode(
 	}
 
 	/* di_[amc]time.nsec */
-	xchk_dinode_nsec(sc, ino, &dip->di_atime);
-	xchk_dinode_nsec(sc, ino, &dip->di_mtime);
-	xchk_dinode_nsec(sc, ino, &dip->di_ctime);
+	xchk_dinode_nsec(sc, ino, dip, &dip->di_atime);
+	xchk_dinode_nsec(sc, ino, dip, &dip->di_mtime);
+	xchk_dinode_nsec(sc, ino, dip, &dip->di_ctime);
 
 	/*
 	 * di_size.  xfs_dinode_verify checks for things that screw up
@@ -413,7 +419,7 @@  xchk_dinode(
 	}
 
 	if (dip->di_version >= 3) {
-		xchk_dinode_nsec(sc, ino, &dip->di_crtime);
+		xchk_dinode_nsec(sc, ino, dip, &dip->di_crtime);
 		xchk_inode_flags2(sc, dip, ino, mode, flags, flags2);
 		xchk_inode_cowextsize(sc, dip, ino, mode, flags,
 				flags2);
diff --git a/fs/xfs/scrub/inode_repair.c b/fs/xfs/scrub/inode_repair.c
index 1569b720ee91..bd4374f49035 100644
--- a/fs/xfs/scrub/inode_repair.c
+++ b/fs/xfs/scrub/inode_repair.c
@@ -169,6 +169,8 @@  xrep_dinode_flags(
 		flags2 &= ~XFS_DIFLAG2_REFLINK;
 	if (flags2 & XFS_DIFLAG2_REFLINK)
 		flags2 &= ~XFS_DIFLAG2_DAX;
+	if (!xfs_sb_version_hasbigtime(&mp->m_sb))
+		flags2 &= ~XFS_DIFLAG2_BIGTIME;
 	dip->di_flags = cpu_to_be16(flags);
 	dip->di_flags2 = cpu_to_be64(flags2);
 }
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index b45f7bdb6122..9863081bdfe9 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -850,6 +850,8 @@  xfs_ialloc(
 	if (ip->i_d.di_version == 3) {
 		inode_set_iversion(inode, 1);
 		ip->i_d.di_flags2 = 0;
+		if (xfs_sb_version_hasbigtime(&ip->i_mount->m_sb))
+			ip->i_d.di_flags2 |= XFS_DIFLAG2_BIGTIME;
 		ip->i_d.di_cowextsize = 0;
 		ip->i_d.di_crtime = tv;
 	}
@@ -911,16 +913,12 @@  xfs_ialloc(
 		    (pip->i_d.di_flags2 & XFS_DIFLAG2_ANY) &&
 		    pip->i_d.di_version == 3 &&
 		    ip->i_d.di_version == 3) {
-			uint64_t	di_flags2 = 0;
-
 			if (pip->i_d.di_flags2 & XFS_DIFLAG2_COWEXTSIZE) {
-				di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
+				ip->i_d.di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
 				ip->i_d.di_cowextsize = pip->i_d.di_cowextsize;
 			}
 			if (pip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
-				di_flags2 |= XFS_DIFLAG2_DAX;
-
-			ip->i_d.di_flags2 |= di_flags2;
+				ip->i_d.di_flags2 |= XFS_DIFLAG2_DAX;
 		}
 		/* FALLTHROUGH */
 	case S_IFLNK:
@@ -3000,6 +2998,8 @@  xfs_ifree(
 	VFS_I(ip)->i_mode = 0;		/* mark incore inode as free */
 	ip->i_d.di_flags = 0;
 	ip->i_d.di_flags2 = 0;
+	if (xfs_sb_version_hasbigtime(&ip->i_mount->m_sb))
+		ip->i_d.di_flags2 |= XFS_DIFLAG2_BIGTIME;
 	ip->i_d.di_dmevmask = 0;
 	ip->i_d.di_forkoff = 0;		/* mark the attr fork not in use */
 	ip->i_d.di_format = XFS_DINODE_FMT_EXTENTS;
@@ -4083,6 +4083,13 @@  xfs_iflush_int(
 			__func__, ip->i_ino, ip->i_d.di_forkoff, ip);
 		goto corrupt_out;
 	}
+	if (xfs_sb_version_hasbigtime(&mp->m_sb) &&
+	    !(ip->i_d.di_flags2 & XFS_DIFLAG2_BIGTIME)) {
+		xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
+			"%s: bad inode %Lu, bigtime unset, ptr "PTR_FMT,
+			__func__, ip->i_ino, ip);
+		goto corrupt_out;
+	}
 
 	/*
 	 * Inode item log recovery for v2 inodes are dependent on the
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index a8d3c6aad1b8..168d53062fab 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -297,9 +297,16 @@  xfs_inode_item_format_attr_fork(
 
 static inline void
 xfs_from_log_timestamp(
+	struct xfs_log_dinode		*from,
 	union xfs_timestamp		*ts,
 	const union xfs_ictimestamp	*its)
 {
+	if (from->di_version >= 3 &&
+	    (from->di_flags2 & XFS_DIFLAG2_BIGTIME)) {
+		ts->t_bigtime = cpu_to_be64(its->t_bigtime);
+		return;
+	}
+
 	ts->t_sec = cpu_to_be32(its->t_sec);
 	ts->t_nsec = cpu_to_be32(its->t_nsec);
 }
@@ -321,9 +328,9 @@  xfs_log_dinode_to_disk(
 	to->di_projid_hi = cpu_to_be16(from->di_projid_hi);
 	memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
 
-	xfs_from_log_timestamp(&to->di_atime, &from->di_atime);
-	xfs_from_log_timestamp(&to->di_mtime, &from->di_mtime);
-	xfs_from_log_timestamp(&to->di_ctime, &from->di_ctime);
+	xfs_from_log_timestamp(from, &to->di_atime, &from->di_atime);
+	xfs_from_log_timestamp(from, &to->di_mtime, &from->di_mtime);
+	xfs_from_log_timestamp(from, &to->di_ctime, &from->di_ctime);
 
 	to->di_size = cpu_to_be64(from->di_size);
 	to->di_nblocks = cpu_to_be64(from->di_nblocks);
@@ -339,7 +346,7 @@  xfs_log_dinode_to_disk(
 
 	if (from->di_version == 3) {
 		to->di_changecount = cpu_to_be64(from->di_changecount);
-		xfs_from_log_timestamp(&to->di_crtime, &from->di_crtime);
+		xfs_from_log_timestamp(from, &to->di_crtime, &from->di_crtime);
 		to->di_flags2 = cpu_to_be64(from->di_flags2);
 		to->di_cowextsize = cpu_to_be32(from->di_cowextsize);
 		to->di_ino = cpu_to_be64(from->di_ino);
@@ -354,9 +361,20 @@  xfs_log_dinode_to_disk(
 
 static inline void
 xfs_to_log_timestamp(
+	struct xfs_icdinode		*from,
 	union xfs_ictimestamp		*its,
 	const struct timespec64		*ts)
 {
+	if (from->di_version >= 3 &&
+	    (from->di_flags2 & XFS_DIFLAG2_BIGTIME)) {
+		uint64_t		t;
+
+		t = (uint64_t)(ts->tv_sec + XFS_INO_BIGTIME_EPOCH);
+		t *= NSEC_PER_SEC;
+		its->t_bigtime = t + ts->tv_nsec;
+		return;
+	}
+
 	its->t_sec = ts->tv_sec;
 	its->t_nsec = ts->tv_nsec;
 }
@@ -381,9 +399,9 @@  xfs_inode_to_log_dinode(
 
 	memset(to->di_pad, 0, sizeof(to->di_pad));
 	memset(to->di_pad3, 0, sizeof(to->di_pad3));
-	xfs_to_log_timestamp(&to->di_atime, &inode->i_atime);
-	xfs_to_log_timestamp(&to->di_mtime, &inode->i_mtime);
-	xfs_to_log_timestamp(&to->di_ctime, &inode->i_ctime);
+	xfs_to_log_timestamp(from, &to->di_atime, &inode->i_atime);
+	xfs_to_log_timestamp(from, &to->di_mtime, &inode->i_mtime);
+	xfs_to_log_timestamp(from, &to->di_ctime, &inode->i_ctime);
 	to->di_nlink = inode->i_nlink;
 	to->di_gen = inode->i_generation;
 	to->di_mode = inode->i_mode;
@@ -404,7 +422,7 @@  xfs_inode_to_log_dinode(
 
 	if (from->di_version == 3) {
 		to->di_changecount = inode_peek_iversion(inode);
-		xfs_to_log_timestamp(&to->di_crtime, &from->di_crtime);
+		xfs_to_log_timestamp(from, &to->di_crtime, &from->di_crtime);
 		to->di_flags2 = from->di_flags2;
 		to->di_cowextsize = from->di_cowextsize;
 		to->di_ino = ip->i_ino;
@@ -412,6 +430,8 @@  xfs_inode_to_log_dinode(
 		memset(to->di_pad2, 0, sizeof(to->di_pad2));
 		uuid_copy(&to->di_uuid, &ip->i_mount->m_sb.sb_meta_uuid);
 		to->di_flushiter = 0;
+		ASSERT((from->di_flags2 & XFS_DIFLAG2_BIGTIME) ||
+		       !xfs_sb_version_hasbigtime(&ip->i_mount->m_sb));
 	} else {
 		to->di_flushiter = from->di_flushiter;
 	}
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index d11857125f45..911b71708587 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1076,7 +1076,8 @@  xfs_flags2diflags2(
 	unsigned int		xflags)
 {
 	uint64_t		di_flags2 =
-		(ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK);
+		(ip->i_d.di_flags2 & (XFS_DIFLAG2_REFLINK |
+				      XFS_DIFLAG2_BIGTIME));
 
 	if (xflags & FS_XFLAG_DAX)
 		di_flags2 |= XFS_DIFLAG2_DAX;
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 5a3372fb6e6d..86b9e0e07f84 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -25,6 +25,9 @@  xfs_check_ondisk_structs(void)
 	/* make sure timestamp limits are correct */
 	XFS_CHECK_VALUE(XFS_INO_TIME_MIN, 			-2147483648LL);
 	XFS_CHECK_VALUE(XFS_INO_TIME_MAX,			2147483647LL);
+	XFS_CHECK_VALUE(XFS_INO_BIGTIME_EPOCH,			2147483648LL);
+	XFS_CHECK_VALUE(XFS_INO_BIGTIME_MIN,			-2147483648LL);
+	XFS_CHECK_VALUE(XFS_INO_BIGTIME_MAX,			16299260425LL);
 	XFS_CHECK_VALUE(XFS_DQ_TIMEOUT_MIN,			1LL);
 	XFS_CHECK_VALUE(XFS_DQ_TIMEOUT_MAX,			4294967295LL);
 	XFS_CHECK_VALUE(XFS_DQ_GRACE_MIN,			0LL);
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 3bddf13cd8ea..0dd6bc7b82c1 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1582,8 +1582,13 @@  xfs_fc_fill_super(
 	sb->s_maxbytes = xfs_max_file_offset(sb->s_blocksize_bits);
 	sb->s_max_links = XFS_MAXLINK;
 	sb->s_time_gran = 1;
-	sb->s_time_min = XFS_INO_TIME_MIN;
-	sb->s_time_max = XFS_INO_TIME_MAX;
+	if (xfs_sb_version_hasbigtime(&mp->m_sb)) {
+		sb->s_time_min = XFS_INO_BIGTIME_MIN;
+		sb->s_time_max = XFS_INO_BIGTIME_MAX;
+	} else {
+		sb->s_time_min = XFS_INO_TIME_MIN;
+		sb->s_time_max = XFS_INO_TIME_MAX;
+	}
 	sb->s_iflags |= SB_I_CGROUPWB;
 
 	set_posix_acl_flag(sb);
@@ -1592,6 +1597,10 @@  xfs_fc_fill_super(
 	if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5)
 		sb->s_flags |= SB_I_VERSION;
 
+	if (xfs_sb_version_hasbigtime(&mp->m_sb))
+		xfs_warn(mp,
+ "EXPERIMENTAL big timestamp feature in use. Use at your own risk!");
+
 	if (mp->m_flags & XFS_MOUNT_DAX) {
 		bool rtdev_is_dax = false, datadev_is_dax;