btrfsprogs/0124-btrfs-progs-Add-utility-to-dump-all-superblocks-foun.patch

From db874f1e8924e86bbdee6600b0e5b3e6d11f9238 Mon Sep 17 00:00:00 2001
From: David Marcin <djmarcin@google.com>
Date: Tue, 22 Nov 2011 10:08:00 -0800
Subject: [PATCH 25/35] btrfs-progs: Add utility to dump all superblocks found
 on a device.

Signed-off-by: David Marcin <djmarcin@google.com>
---
 .gitignore         |    4 ++
 Makefile           |    9 ++++-
 btrfs-dump-super.c |   87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+), 2 deletions(-)
 create mode 100644 btrfs-dump-super.c

Index: btrfs-progs-v0.19-117-g6da41f2/.gitignore
===================================================================
--- btrfs-progs-v0.19-117-g6da41f2.orig/.gitignore
+++ btrfs-progs-v0.19-117-g6da41f2/.gitignore
@@ -3,12 +3,16 @@
 version.h
 man/*.gz
 btrfs
+btrfs-corrupt-block
 btrfs-debug-tree
+btrfs-dump-super
 btrfs-map-logical
+btrfs-select-super
 btrfs-show
 btrfs-vol
 btrfsck
 btrfsctl
+calc-size
 find-root
 mkfs.btrfs
 repair
Index: btrfs-progs-v0.19-117-g6da41f2/Makefile
===================================================================
--- btrfs-progs-v0.19-117-g6da41f2.orig/Makefile
+++ btrfs-progs-v0.19-117-g6da41f2/Makefile
@@ -17,7 +17,8 @@ LIBS=-luuid
 RESTORE_LIBS=-lz
 
 progs = btrfsctl mkfs.btrfs btrfs-debug-tree btrfs-show btrfs-vol btrfsck \
-	btrfs btrfs-map-logical restore find-root calc-size btrfs-corrupt-block
+	btrfs btrfs-map-logical restore find-root calc-size btrfs-corrupt-block \
+	btrfs-dump-super
 
 btrfs_man_page_source = btrfs.c btrfs_cmds.c scrub.c
 
@@ -76,6 +77,9 @@ btrfs-zero-log: $(objects) btrfs-zero-lo
 btrfs-select-super: $(objects) btrfs-select-super.o
 	$(CC) $(CFLAGS) -o btrfs-select-super $(objects) btrfs-select-super.o $(LDFLAGS) $(LIBS)
 
+btrfs-dump-super: $(objects) btrfs-dump-super.o
+	$(CC) $(CFLAGS) -o btrfs-dump-super $(objects) btrfs-dump-super.o $(LDFLAGS) $(LIBS)
+
 btrfstune: $(objects) btrfstune.o
 	$(CC) $(CFLAGS) -o btrfstune $(objects) btrfstune.o $(LDFLAGS) $(LIBS)
 
@@ -128,7 +132,8 @@ install-man:
 clean :
 	rm -f man/btrfs.8.in
 	rm -f $(progs) cscope.out *.o .*.d btrfs-convert btrfs-image btrfs-select-super \
-	      btrfs-zero-log btrfstune dir-test ioctl-test quick-test version.h
+	      btrfs-dump-super btrfs-zero-log btrfstune dir-test ioctl-test quick-test \
+	      version.h
 	rm -f helpmsg.c
 	cd man; make clean
 
Index: btrfs-progs-v0.19-117-g6da41f2/btrfs-dump-super.c
===================================================================
--- /dev/null
+++ btrfs-progs-v0.19-117-g6da41f2/btrfs-dump-super.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2011 Google.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will 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 to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#define _XOPEN_SOURCE 500
+#define _GNU_SOURCE 1
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include "kerncompat.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "version.h"
+
+static void print_usage(void)
+{
+	fprintf(stderr, "usage: btrfs-dump-super dev\n");
+	fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
+	exit(1);
+}
+
+static int read_block(const char* filename,  u64 bytenr, struct btrfs_super_block* sb) {
+	int fd = open(filename, O_RDONLY, 0600);
+	int block_size = sizeof(struct btrfs_super_block);
+	int bytes_read = 0;
+
+	if (fd < 0) {
+		fprintf(stderr, "Could not open %s\n", filename);
+		return -1;
+	}
+
+	bytes_read = pread(fd, sb, block_size, bytenr);
+	if (bytes_read < block_size) {
+		fprintf(stderr, "Only read %d bytes of %d.\n", bytes_read, block_size);
+	}
+
+	close(fd);
+	return bytes_read;
+}
+
+int main(int ac, char **av)
+{
+	int i;
+
+	if (ac != 2)
+		print_usage();
+
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		u64 bytenr = btrfs_sb_offset(i);
+		int fd;
+		struct btrfs_super_block sb;
+		int block_size = sizeof(struct btrfs_super_block);
+		char filename[1024];
+		int bytes_read = read_block(av[optind], bytenr, &sb);
+		if (bytes_read < block_size)
+			continue;
+
+		sprintf(filename, "/tmp/block.%s.%llu",
+			strrchr(av[optind], '/') + 1, bytenr);
+		fd = open(filename, O_CREAT|O_WRONLY, 0644);
+		if (block_size != pwrite(fd, &sb, block_size, 0)) {
+			fprintf(stderr, "Failed to dump superblock %d", i);
+			continue;
+		}
+		fprintf(stderr, "Dumped superblock %s:%d, gen %llu to %s.\n",
+			av[optind], i, sb.generation, filename);
+		close(fd);
+	}
+
+	return 0;
+}