diff --git a/db/convert.c b/db/convert.c
index c0b8e78..e23c2c1 100644
--- a/db/convert.c
+++ b/db/convert.c
@@ -53,6 +53,9 @@
 	CT_RTX,			/* realtime extent */
 	CT_RBMBLOCK,		/* block within rt bitmap */
 	CT_RBMWORD,		/* word within rt bitmap */
+	CT_RSUMBLOCK,		/* block within rt summary */
+	CT_RSUMLOG,		/* log level for rtsummary computations */
+	CT_RSUMINFO,		/* info word within rt summary */
 	NCTS
 } ctype_t;
 
@@ -77,6 +80,7 @@
 	xfs_rtblock_t	rtx;
 	xfs_fileoff_t	rbmblock;
 	unsigned int	rbmword;
+	xfs_fileoff_t	rsumblock;
 } cval_t;
 
 static uint64_t		bytevalue(ctype_t ctype, cval_t *val);
@@ -105,6 +109,12 @@
 static const char	*rtx_names[] = { "rtx", "rtextent", NULL };
 static const char	*rbmblock_names[] = { "rbmblock", "rbmb", NULL };
 static const char	*rbmword_names[] = { "rbmword", "rbmw", NULL };
+static const char	*rsumblock_names[] = { "rsumblock", "rsmb", NULL };
+static const char	*rsumlog_names[] = { "rsumlog", "rsml", NULL };
+static const char	*rsumword_names[] = { "rsuminfo", "rsmi", NULL };
+
+static int		rsuminfo;
+static int		rsumlog;
 
 static const ctydesc_t	ctydescs[NCTS] = {
 	[CT_AGBLOCK] = {
@@ -181,39 +191,60 @@
 static const ctydesc_t	ctydescs_rt[NCTS] = {
 	[CT_BBOFF] = {
 		.allowed = M(DADDR) |
-			   M(RTBLOCK),
+			   M(RTBLOCK) |
+			   M(RSUMLOG),
 		.names   = bboff_names,
 	},
 	[CT_BLKOFF] = {
-		.allowed = M(RTBLOCK),
+		.allowed = M(RTBLOCK) |
+			   M(RSUMLOG),
 		.names   = rtblkoff_names,
 	},
 	[CT_BYTE] = {
-		.allowed = 0,
+		.allowed = M(RSUMLOG),
 		.names   = byte_names,
 	},
 	[CT_DADDR] = {
-		.allowed = M(BBOFF),
+		.allowed = M(BBOFF) |
+			   M(RSUMLOG),
 		.names   = daddr_names,
 	},
 	[CT_RTBLOCK] = {
 		.allowed = M(BBOFF) |
-			   M(BLKOFF),
+			   M(BLKOFF) |
+			   M(RSUMLOG),
 		.names   = rtblock_names,
 	},
 	[CT_RTX] = {
 		.allowed = M(BBOFF) |
-			   M(BLKOFF),
+			   M(BLKOFF) |
+			   M(RSUMLOG),
 		.names   = rtx_names,
 	},
 	[CT_RBMBLOCK] = {
-		.allowed = M(RBMWORD),
+		.allowed = M(RBMWORD) |
+			   M(RSUMLOG),
 		.names   = rbmblock_names,
 	},
 	[CT_RBMWORD] = {
-		.allowed = M(RBMBLOCK),
+		.allowed = M(RBMBLOCK) |
+			   M(RSUMLOG),
 		.names   = rbmword_names,
 	},
+	/* must be specified in order rsumlog -> rsuminfo -> rsumblock */
+	[CT_RSUMBLOCK] = {
+		.allowed = 0,
+		.names   = rsumblock_names,
+	},
+	[CT_RSUMLOG] = {
+		.allowed = M(RSUMINFO) |
+			   M(RSUMBLOCK),
+		.names   = rsumlog_names,
+	},
+	[CT_RSUMINFO] = {
+		.allowed = M(RSUMBLOCK),
+		.names   = rsumword_names,
+	},
 };
 
 static const cmdinfo_t	convert_cmd =
@@ -224,6 +255,39 @@
 	{ "rtconvert", NULL, rtconvert_f, 3, 9, 0, "type num [type num]... type",
 	  "convert from one realtime address form to another", NULL };
 
+static inline uint64_t
+rsumblock_to_bytes(
+	xfs_fileoff_t	rsumblock)
+{
+	/*
+	 * We compute the rt summary file block with this formula:
+	 *   sumoffs = (log2len * sb_rbmblocks) + rbmblock;
+	 *   rsumblock = sumoffs / blockwsize;
+	 *
+	 * Hence the return value is the inverse of this:
+	 *   sumoffs = (rsumblock * blockwsize) + rsuminfo;
+	 *   rbmblock = sumoffs % (log2len * sb_rbmblocks);
+	 */
+	xfs_rtsumoff_t	sumoff;
+	xfs_fileoff_t	rbmblock;
+
+	if (rsumlog < 0) {
+		dbprintf(_("need to set rsumlog\n"));
+		return 0;
+	}
+	if (rsuminfo < 0) {
+		dbprintf(_("need to set rsuminfo\n"));
+		return 0;
+	}
+
+	sumoff = rsuminfo + (rsumblock * mp->m_blockwsize);
+	if (rsumlog)
+		rbmblock = sumoff % (rsumlog * mp->m_sb.sb_rbmblocks);
+	else
+		rbmblock = sumoff;
+	return rbmblock_to_bytes(rbmblock);
+}
+
 static uint64_t
 bytevalue(ctype_t ctype, cval_t *val)
 {
@@ -258,6 +322,16 @@
 		return rbmblock_to_bytes(val->rbmblock);
 	case CT_RBMWORD:
 		return rbmword_to_bytes(val->rbmword);
+	case CT_RSUMBLOCK:
+		return rsumblock_to_bytes(val->rbmblock);
+	case CT_RSUMLOG:
+	case CT_RSUMINFO:
+		/*
+		 * These have to specified before rsumblock, and are stored in
+		 * global variables.  Hence they do not adjust the disk address
+		 * value.
+		 */
+		return 0;
 	case CT_NONE:
 	case NCTS:
 		break;
@@ -361,6 +435,9 @@
 	case CT_RTX:
 	case CT_RBMBLOCK:
 	case CT_RBMWORD:
+	case CT_RSUMBLOCK:
+	case CT_RSUMLOG:
+	case CT_RSUMINFO:
 		/* shouldn't get here */
 		ASSERT(0);
 		break;
@@ -373,6 +450,52 @@
 	return 0;
 }
 
+static inline uint64_t
+rt_daddr_to_rsumblock(
+	struct xfs_mount	*mp,
+	uint64_t		input)
+{
+	xfs_rtblock_t		rtbno;
+	xfs_rtxnum_t		rtx;
+	xfs_fileoff_t		rbmblock;
+	xfs_rtsumoff_t		rsumoff;
+
+	if (rsumlog < 0) {
+		dbprintf(_("need to set rsumlog\n"));
+		return 0;
+	}
+
+	rtbno = xfs_daddr_to_rtb(mp, input >> BBSHIFT);
+	rtx = xfs_rtb_to_rtx(mp, rtbno);
+	rbmblock = xfs_rtx_to_rbmblock(mp, rtx);
+	rsumoff = xfs_rtsumoffs(mp, rsumlog, rbmblock);
+
+	return xfs_rtsumoffs_to_block(mp, rsumoff);
+}
+
+static inline uint64_t
+rt_daddr_to_rsuminfo(
+	struct xfs_mount	*mp,
+	uint64_t		input)
+{
+	xfs_rtblock_t		rtbno;
+	xfs_rtxnum_t		rtx;
+	xfs_fileoff_t		rbmblock;
+	xfs_rtsumoff_t		rsumoff;
+
+	if (rsumlog < 0) {
+		dbprintf(_("need to set rsumlog\n"));
+		return 0;
+	}
+
+	rtbno = xfs_daddr_to_rtb(mp, input >> BBSHIFT);
+	rtx = xfs_rtb_to_rtx(mp, rtbno);
+	rbmblock = xfs_rtx_to_rbmblock(mp, rtx);
+	rsumoff = xfs_rtsumoffs(mp, rsumlog, rbmblock);
+
+	return xfs_rtsumoffs_to_infoword(mp, rsumoff);
+}
+
 static int
 rtconvert_f(int argc, char **argv)
 {
@@ -384,6 +507,9 @@
 	uint64_t	v;
 	ctype_t		wtype;
 
+	rsumlog = -1;
+	rsuminfo = -1;
+
 	/* move past the "rtconvert" command */
 	argc--;
 	argv++;
@@ -452,6 +578,16 @@
 				xfs_rtb_to_rtx(mp,
 					xfs_daddr_to_rtb(mp, v >> BBSHIFT)));
 		break;
+	case CT_RSUMBLOCK:
+		v = rt_daddr_to_rsumblock(mp, v);
+		break;
+	case CT_RSUMLOG:
+		dbprintf(_("cannot convert to rsumlog\n"));
+		return 0;
+		break;
+	case CT_RSUMINFO:
+		v = rt_daddr_to_rsuminfo(mp, v);
+		break;
 	case CT_AGBLOCK:
 	case CT_AGINO:
 	case CT_AGNUMBER:
@@ -535,6 +671,15 @@
 	case CT_RBMWORD:
 		val->rbmword = (unsigned int)v;
 		break;
+	case CT_RSUMBLOCK:
+		val->rsumblock = (xfs_fileoff_t)v;
+		break;
+	case CT_RSUMLOG:
+		rsumlog = (unsigned int)v;
+		break;
+	case CT_RSUMINFO:
+		rsuminfo = (unsigned int)v;
+		break;
 	case CT_NONE:
 	case NCTS:
 		/* NOTREACHED */
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 12fc4f3..7dbb5ce 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -1183,10 +1183,52 @@
 or
 .B rbmw
 (32-bit word within a realtime bitmap block)
+.HP
+.B rsumblock
+or
+.B rsmb
+(realtime summary file block)
+.HP
+.B rsuminfo
+or
+.B rsmi
+(32-bit counter within a realtime summary block)
+.HP
+.B rsumlog
+or
+.B rsml
+(log2len parameter used for summary file offset computations)
 .PD
 .RE
 .IP
 Only conversions that "make sense" are allowed.
+
+Realtime summary file location conversions have the following rules:
+Each info word in the rt summary file counts the number of free extents of a
+given log2(length) that start in a given rt bitmap block.
+
+To compute summary file location information for a given rt bitmap block, a
+log2(extent length) must be specified as the last type/number pair before the
+conversion type, and the type must be
+.BR rsumlog .
+
+For example, these commands tell us where to look in the rt summary file for
+the number of free rtextents of length 2^21 starting in rt bitmap block 30:
+
+.B rtconvert rbmblock 30 rsumlog 21 rsumblock
+
+.B rtconvert rbmblock 30 rsumlog 21 rsuminfo
+
+To compute the rt bitmap block from summary file location, the type/number
+pairs must be specified exactly in the order
+.BR rsumlog ", " rsuminfo ", " rsumblock .
+
+For example, this command tells us which block in the rt bitmap file is
+summarized by info word 809 in rt summary block 10 assuming that the
+maximum free extent length is 2^21 rtextents:
+
+.B rtconvert rsumlog 21 rsuminfo 809 rsumblock 10 rbmblock
+
 .TP
 .BI "sb [" agno ]
 Set current address to SB header in allocation group