[PATCH v2 4/9] xfs_db: add a superblock info command

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

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

Add an 'info' command to pretty-print the superblock geometry.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 db/Makefile       |    2 +
 db/command.c      |    1 +
 db/command.h      |    1 +
 db/info.c         |   74 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_db.8 |    8 ++++++
 5 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 db/info.c

diff --git a/db/Makefile b/db/Makefile
index 6caa6348..c73d7f25 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -14,7 +14,7 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \
 	io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \
 	sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \
 	fuzz.h
-CFILES = $(HFILES:.h=.c) btdump.c
+CFILES = $(HFILES:.h=.c) btdump.c info.c
 LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
 
 LLDLIBS	= $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
diff --git a/db/command.c b/db/command.c
index 12ae5b78..087955e0 100644
--- a/db/command.c
+++ b/db/command.c
@@ -136,6 +136,7 @@ init_commands(void)
 	fsmap_init();
 	help_init();
 	hash_init();
+	info_init();
 	inode_init();
 	input_init();
 	logres_init();
diff --git a/db/command.h b/db/command.h
index 9b4ed2d7..84cd0b10 100644
--- a/db/command.h
+++ b/db/command.h
@@ -41,3 +41,4 @@ extern const cmdinfo_t	*find_command(const char *cmd);
 extern void		init_commands(void);
 
 extern void		btdump_init(void);
+extern void		info_init(void);
diff --git a/db/info.c b/db/info.c
new file mode 100644
index 00000000..05b3c1f0
--- /dev/null
+++ b/db/info.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2018 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include "libxfs.h"
+#include "command.h"
+#include "init.h"
+#include "output.h"
+#include "fsgeom.h"
+
+static void
+info_help(void)
+{
+	dbprintf(_(
+"\n"
+" Pretty-prints the filesystem geometry as derived from the superblock.\n"
+" The output has the same format as mkfs.xfs, xfs_info, and other utilities.\n"
+"\n"
+));
+
+}
+
+static int
+info_f(
+	int			argc,
+	char			**argv)
+{
+	struct xfs_fsop_geom	geo;
+	int			error;
+
+	error = -libxfs_fs_geometry(&mp->m_sb, &geo,
+			XFS_FS_GEOM_MAX_STRUCT_VER);
+	if (error) {
+		dbprintf(_("could not obtain geometry\n"));
+		exitcode = 1;
+		return 0;
+	}
+
+	xfs_report_geom(&geo, fsdevice, x.logname, x.rtname);
+	return 0;
+}
+
+static const struct cmdinfo info_cmd = {
+	.name =		"info",
+	.altname =	"i",
+	.cfunc =	info_f,
+	.argmin =	0,
+	.argmax =	0,
+	.canpush =	0,
+	.args =		NULL,
+	.oneline =	N_("pretty-print superblock info"),
+	.help =		info_help,
+};
+
+void
+info_init(void)
+{
+	add_command(&info_cmd);
+}
diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index 524b1ef6..10f2beb9 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -670,6 +670,14 @@ using the hash function of the XFS directory and attribute implementation.
 .BI "help [" command ]
 Print help for one or all commands.
 .TP
+.B info
+Displays selected geometry information about the filesystem.
+The output will have the same format that
+.BR "mkfs.xfs" "(8)"
+prints when creating a filesystem or
+.BR "xfs_info" "(8)"
+prints when querying a filesystem.
+.TP
 .BI "inode [" inode# ]
 Set the current inode number. If no
 .I inode#