[PATCH v2 20/26] xfs_db: report bigtime format timestamps

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Report the large format timestamps in a human-readable manner if it is
possible to do so without loss of information.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
v2: skip the build bug stuff and check directly for information loss in
the time64_t -> time_t conversion
---
 db/fprint.c              |   73 +++++++++++++++++++++++++++++++++-------------
 db/inode.c               |    4 ++-
 db/sb.c                  |    2 +
 libxfs/libxfs_api_defs.h |    1 +
 4 files changed, 59 insertions(+), 21 deletions(-)

diff --git a/db/fprint.c b/db/fprint.c
index 7ceab29cc608..65accfda3fe4 100644
--- a/db/fprint.c
+++ b/db/fprint.c
@@ -112,23 +112,50 @@ fp_sarray(
 	return 1;
 }
 
-int
-fp_time(
-	void			*obj,
-	int			bit,
-	int			count,
-	char			*fmtstr,
-	int			size,
-	int			arg,
-	int			base,
-	int			array)
+static void
+fp_time64(
+	time64_t		sec)
 {
-	struct timespec64	tv;
-	xfs_timestamp_t		*ts;
-	int			bitpos;
+	time_t			tt = sec;
+	time64_t		tt_sec = tt;
 	char			*c;
+
+	/*
+	 * Stupid time_t shenanigans -- POSIX.1-2017 only requires that this
+	 * type represent a time in seconds.  Since we have no idea if our
+	 * time64_t filesystem timestamps can actually be represented by the C
+	 * library, we resort to converting the input value from time64_t to
+	 * time_t and back to time64_t to check for information loss.  If so,
+	 * we print the raw value; otherwise we print a human-readable value.
+	 */
+	if (tt_sec != sec)
+		goto raw;
+
+	c = ctime(&tt);
+	if (!c)
+		goto raw;
+
+	dbprintf("%24.24s", c);
+	return;
+raw:
+	dbprintf("%lld", sec);
+}
+
+int
+fp_time(
+	void			*obj,
+	int			bit,
+	int			count,
+	char			*fmtstr,
+	int			size,
+	int			arg,
+	int			base,
+	int			array)
+{
+	struct timespec64	tv;
+	xfs_timestamp_t		*ts;
+	int			bitpos;
 	int			i;
-	time_t			t;
 
 	ASSERT(bitoffs(bit) == 0);
 	for (i = 0, bitpos = bit;
@@ -139,10 +166,8 @@ fp_time(
 
 		ts = obj + byteize(bitpos);
 		tv = libxfs_inode_from_disk_ts(obj, *ts);
-		t = tv.tv_sec;
 
-		c = ctime(&t);
-		dbprintf("%24.24s", c);
+		fp_time64(tv.tv_sec);
 
 		if (i < count - 1)
 			dbprintf(" ");
@@ -195,7 +220,8 @@ fp_qtimer(
 	int			base,
 	int			array)
 {
-	uint32_t		sec;
+	struct xfs_disk_dquot	*ddq = obj;
+	time64_t		sec;
 	__be32			*t;
 	int			bitpos;
 	int			i;
@@ -208,9 +234,16 @@ fp_qtimer(
 			dbprintf("%d:", i + base);
 
 		t = obj + byteize(bitpos);
-		sec = be32_to_cpu(*t);
+		sec = libxfs_dquot_from_disk_ts(ddq, *t);
 
-		dbprintf("%u", sec);
+		/*
+		 * Display the raw value if it's the default grace expiration
+		 * period (root dquot) or if the quota has not expired.
+		 */
+		if (ddq->d_id == 0 || sec == 0)
+			dbprintf("%lld", sec);
+		else
+			fp_time64(sec);
 
 		if (i < count - 1)
 			dbprintf(" ");
diff --git a/db/inode.c b/db/inode.c
index cc0e680aadea..f0e08ebf5ad9 100644
--- a/db/inode.c
+++ b/db/inode.c
@@ -175,10 +175,12 @@ const field_t	inode_v3_flds[] = {
 	{ "dax", FLDT_UINT1,
 	  OI(COFF(flags2) + bitsz(uint64_t) - XFS_DIFLAG2_DAX_BIT - 1), C1,
 	  0, TYP_NONE },
+	{ "bigtime", FLDT_UINT1,
+	  OI(COFF(flags2) + bitsz(uint64_t) - XFS_DIFLAG2_BIGTIME_BIT - 1), C1,
+	  0, TYP_NONE },
 	{ NULL }
 };
 
-
 const field_t	timestamp_flds[] = {
 	{ "sec", FLDT_TIME, OI(0), C1, 0, TYP_NONE },
 	{ "nsec", FLDT_NSEC, OI(0), C1, 0, TYP_NONE },
diff --git a/db/sb.c b/db/sb.c
index cfc2e32023fc..3608508a7eb8 100644
--- a/db/sb.c
+++ b/db/sb.c
@@ -800,6 +800,8 @@ version_string(
 		strcat(s, ",REFLINK");
 	if (xfs_sb_version_hasinobtcounts(sbp))
 		strcat(s, ",INOBTCNT");
+	if (xfs_sb_version_hasbigtime(sbp))
+		strcat(s, ",BIGTIME");
 	return s;
 }
 
diff --git a/libxfs/libxfs_api_defs.h b/libxfs/libxfs_api_defs.h
index 40da71ab3163..419e6d9888cf 100644
--- a/libxfs/libxfs_api_defs.h
+++ b/libxfs/libxfs_api_defs.h
@@ -99,6 +99,7 @@
 #define xfs_dir_replace			libxfs_dir_replace
 
 #define xfs_dqblk_repair		libxfs_dqblk_repair
+#define xfs_dquot_from_disk_ts		libxfs_dquot_from_disk_ts
 #define xfs_dquot_verify		libxfs_dquot_verify
 
 #define xfs_finobt_calc_reserves	libxfs_finobt_calc_reserves