btrfs-progs: introduce inspect-internal dump-super

The long-term plan is to merge the features of standalone tools
into the btrfs binary, reducing the number of shipped binaries.

Signed-off-by: Alexander Fougner <fougner89@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>

5 files changed, 579 insertions, 514 deletions

diff --git a/Makefile.in b/Makefile.in
index 687df4ac..f950b070 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -70,7 +70,8 @@ objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
 	  extent-cache.o extent_io.o volumes.o utils.o repair.o \
 	  qgroup.o raid6.o free-space-cache.o list_sort.o props.o \
 	  ulist.o qgroup-verify.o backref.o string-table.o task-utils.o \
-	  inode.o file.o find-root.o free-space-tree.o help.o cmds-inspect-dump-tree.o
+	  inode.o file.o find-root.o free-space-tree.o help.o \
+	  cmds-inspect-dump-tree.o cmds-inspect-dump-super.o
 cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
 	       cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \
 	       cmds-quota.o cmds-qgroup.o cmds-replace.o cmds-check.o \
diff --git a/btrfs-show-super.c b/btrfs-show-super.c
index 051bd115..3e2ceb58 100644
--- a/btrfs-show-super.c
+++ b/btrfs-show-super.c
@@ -16,527 +16,21 @@
  * Boston, MA 021110-1307, USA.
  */
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <sys/stat.h>
-#include <ctype.h>
-#include <uuid/uuid.h>
-#include <errno.h>
-
-#include "kerncompat.h"
-#include "ctree.h"
-#include "disk-io.h"
-#include "print-tree.h"
-#include "transaction.h"
-#include "list.h"
 #include "utils.h"
-#include "crc32c.h"
-
-static void print_usage(void);
-static void dump_superblock(struct btrfs_super_block *sb, int full);
-int main(int argc, char **argv);
-static int load_and_dump_sb(char *, int fd, u64 sb_bytenr, int full, int force);
-
-
-static void print_usage(void)
-{
-	fprintf(stderr,
-		"usage: btrfs-show-super [-i super_mirror|-a|-f|-F] dev [dev..]\n");
-	fprintf(stderr, "\t-f : print full superblock information\n");
-	fprintf(stderr, "\t-a : print information of all superblocks\n");
-	fprintf(stderr, "\t-i <super_mirror> : specify which mirror to print out\n");
-	fprintf(stderr, "\t-F : attempt to dump superblocks with bad magic\n");
-	fprintf(stderr, "\t-s <bytenr> : specify alternate superblock offset\n");
-	fprintf(stderr, "%s\n", PACKAGE_STRING);
-}
+#include "commands.h"
+#include "cmds-inspect-dump-super.h"
 
 int main(int argc, char **argv)
 {
-	int opt;
-	int all = 0;
-	int full = 0;
-	int force = 0;
-	char *filename;
-	int fd = -1;
-	int i;
-	u64 arg;
-	u64 sb_bytenr = btrfs_sb_offset(0);
-
-	while ((opt = getopt(argc, argv, "fFai:s:")) != -1) {
-		switch (opt) {
-		case 'i':
-			arg = arg_strtou64(optarg);
-			if (arg >= BTRFS_SUPER_MIRROR_MAX) {
-				fprintf(stderr,
-					"Illegal super_mirror %llu\n",
-					arg);
-				print_usage();
-				exit(1);
-			}
-			sb_bytenr = btrfs_sb_offset(arg);
-			break;
 
-		case 'a':
-			all = 1;
-			break;
-		case 'f':
-			full = 1;
-			break;
-		case 'F':
-			force = 1;
-			break;
-		case 's':
-			sb_bytenr = arg_strtou64(optarg);
-			all = 0;
-			break;
-		default:
-			print_usage();
-			exit(1);
-		}
-	}
+	int ret;
 
 	set_argv0(argv);
-	if (check_argc_min(argc - optind, 1)) {
-		print_usage();
-		exit(1);
-	}
-
-	for (i = optind; i < argc; i++) {
-		filename = argv[i];
-		fd = open(filename, O_RDONLY, 0666);
-		if (fd < 0) {
-			fprintf(stderr, "Could not open %s\n", filename);
-			exit(1);
-		}
-
-		if (all) {
-			int idx;
-			for (idx = 0; idx < BTRFS_SUPER_MIRROR_MAX; idx++) {
-				sb_bytenr = btrfs_sb_offset(idx);
-				if (load_and_dump_sb(filename, fd,
-						sb_bytenr, full, force)) {
-					close(fd);
-					exit(1);
-				}
-
-				putchar('\n');
-			}
-		} else {
-			load_and_dump_sb(filename, fd, sb_bytenr, full, force);
-			putchar('\n');
-		}
-		close(fd);
-	}
-
-	exit(0);
-}
-
-static int load_and_dump_sb(char *filename, int fd, u64 sb_bytenr, int full,
-		int force)
-{
-	u8 super_block_data[BTRFS_SUPER_INFO_SIZE];
-	struct btrfs_super_block *sb;
-	u64 ret;
-
-	sb = (struct btrfs_super_block *)super_block_data;
-
-	ret = pread64(fd, super_block_data, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
-	if (ret != BTRFS_SUPER_INFO_SIZE) {
-		/* check if the disk if too short for further superblock */
-		if (ret == 0 && errno == 0)
-			return 0;
-
-		fprintf(stderr,
-		   "ERROR: Failed to read the superblock on %s at %llu\n",
-		   filename, (unsigned long long)sb_bytenr);
-		fprintf(stderr,
-		   "ERROR: error = '%s', errno = %d\n", strerror(errno), errno);
-		return 1;
-	}
-	printf("superblock: bytenr=%llu, device=%s\n", sb_bytenr, filename);
-	printf("---------------------------------------------------------\n");
-	if (btrfs_super_magic(sb) != BTRFS_MAGIC && !force) {
-		fprintf(stderr,
-		    "ERROR: bad magic on superblock on %s at %llu\n",
-		    filename, (unsigned long long)sb_bytenr);
-	} else {
-		dump_superblock(sb, full);
-	}
-	return 0;
-}
-
-static int check_csum_sblock(void *sb, int csum_size)
-{
-	char result[BTRFS_CSUM_SIZE];
-	u32 crc = ~(u32)0;
-
-	crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE,
-				crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
-	btrfs_csum_final(crc, result);
-
-	return !memcmp(sb, &result, csum_size);
-}
-
-static void print_sys_chunk_array(struct btrfs_super_block *sb)
-{
-	struct extent_buffer *buf;
-	struct btrfs_disk_key *disk_key;
-	struct btrfs_chunk *chunk;
-	u8 *array_ptr;
-	unsigned long sb_array_offset;
-	u32 num_stripes;
-	u32 array_size;
-	u32 len = 0;
-	u32 cur_offset;
-	struct btrfs_key key;
-	int item;
-
-	buf = malloc(sizeof(*buf) + sizeof(*sb));
-	if (!buf) {
-		fprintf(stderr, "%s\n", strerror(ENOMEM));
-		exit(1);
-	}
-	write_extent_buffer(buf, sb, 0, sizeof(*sb));
-	array_size = btrfs_super_sys_array_size(sb);
-
-	array_ptr = sb->sys_chunk_array;
-	sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
-	cur_offset = 0;
-	item = 0;
-
-	while (cur_offset < array_size) {
-		disk_key = (struct btrfs_disk_key *)array_ptr;
-		len = sizeof(*disk_key);
-		if (cur_offset + len > array_size)
-			goto out_short_read;
-
-		btrfs_disk_key_to_cpu(&key, disk_key);
-
-		array_ptr += len;
-		sb_array_offset += len;
-		cur_offset += len;
-
-		printf("\titem %d ", item);
-		btrfs_print_key(disk_key);
-		putchar('\n');
-
-		if (key.type == BTRFS_CHUNK_ITEM_KEY) {
-			chunk = (struct btrfs_chunk *)sb_array_offset;
-			/*
-			 * At least one btrfs_chunk with one stripe must be
-			 * present, exact stripe count check comes afterwards
-			 */
-			len = btrfs_chunk_item_size(1);
-			if (cur_offset + len > array_size)
-				goto out_short_read;
-
-			print_chunk(buf, chunk);
-			num_stripes = btrfs_chunk_num_stripes(buf, chunk);
-			if (!num_stripes) {
-				printk(
-	    "ERROR: invalid number of stripes %u in sys_array at offset %u\n",
-					num_stripes, cur_offset);
-				break;
-			}
-			len = btrfs_chunk_item_size(num_stripes);
-			if (cur_offset + len > array_size)
-				goto out_short_read;
-		} else {
-			printk(
-		"ERROR: unexpected item type %u in sys_array at offset %u\n",
-				(u32)key.type, cur_offset);
- 			break;
-		}
-		array_ptr += len;
-		sb_array_offset += len;
-		cur_offset += len;
-
-		item++;
-	}
-
-	free(buf);
-	return;
-
-out_short_read:
-	printk("ERROR: sys_array too short to read %u bytes at offset %u\n",
-			len, cur_offset);
-	free(buf);
-}
-
-static int empty_backup(struct btrfs_root_backup *backup)
-{
-	if (backup == NULL ||
-		(backup->tree_root == 0 &&
-		 backup->tree_root_gen == 0))
-		return 1;
-	return 0;
-}
-
-static void print_root_backup(struct btrfs_root_backup *backup)
-{
-	printf("\t\tbackup_tree_root:\t%llu\tgen: %llu\tlevel: %d\n",
-			btrfs_backup_tree_root(backup),
-			btrfs_backup_tree_root_gen(backup),
-			btrfs_backup_tree_root_level(backup));
-	printf("\t\tbackup_chunk_root:\t%llu\tgen: %llu\tlevel: %d\n",
-			btrfs_backup_chunk_root(backup),
-			btrfs_backup_chunk_root_gen(backup),
-			btrfs_backup_chunk_root_level(backup));
-	printf("\t\tbackup_extent_root:\t%llu\tgen: %llu\tlevel: %d\n",
-			btrfs_backup_extent_root(backup),
-			btrfs_backup_extent_root_gen(backup),
-			btrfs_backup_extent_root_level(backup));
-	printf("\t\tbackup_fs_root:\t\t%llu\tgen: %llu\tlevel: %d\n",
-			btrfs_backup_fs_root(backup),
-			btrfs_backup_fs_root_gen(backup),
-			btrfs_backup_fs_root_level(backup));
-	printf("\t\tbackup_dev_root:\t%llu\tgen: %llu\tlevel: %d\n",
-			btrfs_backup_dev_root(backup),
-			btrfs_backup_dev_root_gen(backup),
-			btrfs_backup_dev_root_level(backup));
-	printf("\t\tbackup_csum_root:\t%llu\tgen: %llu\tlevel: %d\n",
-			btrfs_backup_csum_root(backup),
-			btrfs_backup_csum_root_gen(backup),
-			btrfs_backup_csum_root_level(backup));
-
-	printf("\t\tbackup_total_bytes:\t%llu\n",
-					btrfs_backup_total_bytes(backup));
-	printf("\t\tbackup_bytes_used:\t%llu\n",
-					btrfs_backup_bytes_used(backup));
-	printf("\t\tbackup_num_devices:\t%llu\n",
-					btrfs_backup_num_devices(backup));
-	putchar('\n');
-}
-
-static void print_backup_roots(struct btrfs_super_block *sb)
-{
-	struct btrfs_root_backup *backup;
-	int i;
-
-	for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
-		backup = sb->super_roots + i;
-		if (!empty_backup(backup)) {
-			printf("\tbackup %d:\n", i);
-			print_root_backup(backup);
-		}
-	}
-}
-
-struct readable_flag_entry {
-	u64 bit;
-	char *output;
-};
-
-#define DEF_INCOMPAT_FLAG_ENTRY(bit_name)		\
-	{BTRFS_FEATURE_INCOMPAT_##bit_name, #bit_name}
-
-static struct readable_flag_entry incompat_flags_array[] = {
-	DEF_INCOMPAT_FLAG_ENTRY(MIXED_BACKREF),
-	DEF_INCOMPAT_FLAG_ENTRY(DEFAULT_SUBVOL),
-	DEF_INCOMPAT_FLAG_ENTRY(MIXED_GROUPS),
-	DEF_INCOMPAT_FLAG_ENTRY(COMPRESS_LZO),
-	DEF_INCOMPAT_FLAG_ENTRY(COMPRESS_LZOv2),
-	DEF_INCOMPAT_FLAG_ENTRY(BIG_METADATA),
-	DEF_INCOMPAT_FLAG_ENTRY(EXTENDED_IREF),
-	DEF_INCOMPAT_FLAG_ENTRY(RAID56),
-	DEF_INCOMPAT_FLAG_ENTRY(SKINNY_METADATA),
-	DEF_INCOMPAT_FLAG_ENTRY(NO_HOLES)
-};
-static const int incompat_flags_num = sizeof(incompat_flags_array) /
-				      sizeof(struct readable_flag_entry);
-
-#define DEF_HEADER_FLAG_ENTRY(bit_name)			\
-	{BTRFS_HEADER_FLAG_##bit_name, #bit_name}
-#define DEF_SUPER_FLAG_ENTRY(bit_name)			\
-	{BTRFS_SUPER_FLAG_##bit_name, #bit_name}
-
-static struct readable_flag_entry super_flags_array[] = {
-	DEF_HEADER_FLAG_ENTRY(WRITTEN),
-	DEF_HEADER_FLAG_ENTRY(RELOC),
-	DEF_SUPER_FLAG_ENTRY(CHANGING_FSID),
-	DEF_SUPER_FLAG_ENTRY(SEEDING),
-	DEF_SUPER_FLAG_ENTRY(METADUMP),
-	DEF_SUPER_FLAG_ENTRY(METADUMP_V2)
-};
-static const int super_flags_num = ARRAY_SIZE(super_flags_array);
-
-#define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
-				 BTRFS_HEADER_FLAG_RELOC |\
-				 BTRFS_SUPER_FLAG_CHANGING_FSID |\
-				 BTRFS_SUPER_FLAG_SEEDING |\
-				 BTRFS_SUPER_FLAG_METADUMP |\
-				 BTRFS_SUPER_FLAG_METADUMP_V2)
-
-static void __print_readable_flag(u64 flag, struct readable_flag_entry *array,
-				  int array_size, u64 supported_flags)
-{
-	int i;
-	int first = 1;
-	struct readable_flag_entry *entry;
-
-	if (!flag)
-		return;
-
-	printf("\t\t\t( ");
-	for (i = 0; i < array_size; i++) {
-		entry = array + i;
-		if (flag & entry->bit) {
-			if (first)
-				printf("%s ", entry->output);
-			else
-				printf("|\n\t\t\t  %s ", entry->output);
-			first = 0;
-		}
-	}
-	flag &= ~supported_flags;
-	if (flag) {
-		if (first)
-			printf("unknown flag: 0x%llx ", flag);
-		else
-			printf("|\n\t\t\t  unknown flag: 0x%llx ", flag);
-	}
-	printf(")\n");
-}
-
-static void print_readable_incompat_flag(u64 flag)
-{
-	return __print_readable_flag(flag, incompat_flags_array,
-				     incompat_flags_num,
-				     BTRFS_FEATURE_INCOMPAT_SUPP);
-}
-
-static void print_readable_super_flag(u64 flag)
-{
-	return __print_readable_flag(flag, super_flags_array,
-				     super_flags_num, BTRFS_SUPER_FLAG_SUPP);
-}
-
-static void dump_superblock(struct btrfs_super_block *sb, int full)
-{
-	int i;
-	char *s, buf[BTRFS_UUID_UNPARSED_SIZE];
-	u8 *p;
-
-	printf("csum\t\t\t0x");
-	for (i = 0, p = sb->csum; i < btrfs_super_csum_size(sb); i++)
-		printf("%02x", p[i]);
-	if (check_csum_sblock(sb, btrfs_super_csum_size(sb)))
-		printf(" [match]");
-	else
-		printf(" [DON'T MATCH]");
-	putchar('\n');
-
-	printf("bytenr\t\t\t%llu\n",
-		(unsigned long long)btrfs_super_bytenr(sb));
-	printf("flags\t\t\t0x%llx\n",
-		(unsigned long long)btrfs_super_flags(sb));
-	print_readable_super_flag(btrfs_super_flags(sb));
-
-	printf("magic\t\t\t");
-	s = (char *) &sb->magic;
-	for (i = 0; i < 8; i++)
-		putchar(isprint(s[i]) ? s[i] : '.');
-	if (btrfs_super_magic(sb) == BTRFS_MAGIC)
-		printf(" [match]\n");
-	else
-		printf(" [DON'T MATCH]\n");
-
-	uuid_unparse(sb->fsid, buf);
-	printf("fsid\t\t\t%s\n", buf);
-
-	printf("label\t\t\t");
-	s = sb->label;
-	for (i = 0; i < BTRFS_LABEL_SIZE && s[i]; i++)
-		putchar(isprint(s[i]) ? s[i] : '.');
-	putchar('\n');
-
-	printf("generation\t\t%llu\n",
-	       (unsigned long long)btrfs_super_generation(sb));
-	printf("root\t\t\t%llu\n", (unsigned long long)btrfs_super_root(sb));
-	printf("sys_array_size\t\t%llu\n",
-	       (unsigned long long)btrfs_super_sys_array_size(sb));
-	printf("chunk_root_generation\t%llu\n",
-	       (unsigned long long)btrfs_super_chunk_root_generation(sb));
-	printf("root_level\t\t%llu\n",
-	       (unsigned long long)btrfs_super_root_level(sb));
-	printf("chunk_root\t\t%llu\n",
-	       (unsigned long long)btrfs_super_chunk_root(sb));
-	printf("chunk_root_level\t%llu\n",
-	       (unsigned long long)btrfs_super_chunk_root_level(sb));
-	printf("log_root\t\t%llu\n",
-	       (unsigned long long)btrfs_super_log_root(sb));
-	printf("log_root_transid\t%llu\n",
-	       (unsigned long long)btrfs_super_log_root_transid(sb));
-	printf("log_root_level\t\t%llu\n",
-	       (unsigned long long)btrfs_super_log_root_level(sb));
-	printf("total_bytes\t\t%llu\n",
-	       (unsigned long long)btrfs_super_total_bytes(sb));
-	printf("bytes_used\t\t%llu\n",
-	       (unsigned long long)btrfs_super_bytes_used(sb));
-	printf("sectorsize\t\t%llu\n",
-	       (unsigned long long)btrfs_super_sectorsize(sb));
-	printf("nodesize\t\t%llu\n",
-	       (unsigned long long)btrfs_super_nodesize(sb));
-	printf("leafsize\t\t%llu\n",
-	       (unsigned long long)btrfs_super_leafsize(sb));
-	printf("stripesize\t\t%llu\n",
-	       (unsigned long long)btrfs_super_stripesize(sb));
-	printf("root_dir\t\t%llu\n",
-	       (unsigned long long)btrfs_super_root_dir(sb));
-	printf("num_devices\t\t%llu\n",
-	       (unsigned long long)btrfs_super_num_devices(sb));
-	printf("compat_flags\t\t0x%llx\n",
-	       (unsigned long long)btrfs_super_compat_flags(sb));
-	printf("compat_ro_flags\t\t0x%llx\n",
-	       (unsigned long long)btrfs_super_compat_ro_flags(sb));
-	printf("incompat_flags\t\t0x%llx\n",
-	       (unsigned long long)btrfs_super_incompat_flags(sb));
-	print_readable_incompat_flag(btrfs_super_incompat_flags(sb));
-	printf("csum_type\t\t%llu\n",
-	       (unsigned long long)btrfs_super_csum_type(sb));
-	printf("csum_size\t\t%llu\n",
-	       (unsigned long long)btrfs_super_csum_size(sb));
-	printf("cache_generation\t%llu\n",
-	       (unsigned long long)btrfs_super_cache_generation(sb));
-	printf("uuid_tree_generation\t%llu\n",
-	       (unsigned long long)btrfs_super_uuid_tree_generation(sb));
 
-	uuid_unparse(sb->dev_item.uuid, buf);
-	printf("dev_item.uuid\t\t%s\n", buf);
+	if (argc > 1 && !strcmp(argv[1], "--help"))
+		usage(cmd_inspect_dump_super_usage);
 
-	uuid_unparse(sb->dev_item.fsid, buf);
-	printf("dev_item.fsid\t\t%s %s\n", buf,
-		!memcmp(sb->dev_item.fsid, sb->fsid, BTRFS_FSID_SIZE) ?
-			"[match]" : "[DON'T MATCH]");
+	ret = cmd_inspect_dump_super(argc, argv);
 
-	printf("dev_item.type\t\t%llu\n", (unsigned long long)
-	       btrfs_stack_device_type(&sb->dev_item));
-	printf("dev_item.total_bytes\t%llu\n", (unsigned long long)
-	       btrfs_stack_device_total_bytes(&sb->dev_item));
-	printf("dev_item.bytes_used\t%llu\n", (unsigned long long)
-	       btrfs_stack_device_bytes_used(&sb->dev_item));
-	printf("dev_item.io_align\t%u\n", (unsigned int)
-	       btrfs_stack_device_io_align(&sb->dev_item));
-	printf("dev_item.io_width\t%u\n", (unsigned int)
-	       btrfs_stack_device_io_width(&sb->dev_item));
-	printf("dev_item.sector_size\t%u\n", (unsigned int)
-	       btrfs_stack_device_sector_size(&sb->dev_item));
-	printf("dev_item.devid\t\t%llu\n",
-	       btrfs_stack_device_id(&sb->dev_item));
-	printf("dev_item.dev_group\t%u\n", (unsigned int)
-	       btrfs_stack_device_group(&sb->dev_item));
-	printf("dev_item.seek_speed\t%u\n", (unsigned int)
-	       btrfs_stack_device_seek_speed(&sb->dev_item));
-	printf("dev_item.bandwidth\t%u\n", (unsigned int)
-	       btrfs_stack_device_bandwidth(&sb->dev_item));
-	printf("dev_item.generation\t%llu\n", (unsigned long long)
-	       btrfs_stack_device_generation(&sb->dev_item));
-	if (full) {
-		printf("sys_chunk_array[%d]:\n", BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
-		print_sys_chunk_array(sb);
-		printf("backup_roots[%d]:\n", BTRFS_NUM_BACKUP_ROOTS);
-		print_backup_roots(sb);
-	}
+	return ret;
 }
diff --git a/cmds-inspect-dump-super.c b/cmds-inspect-dump-super.c
new file mode 100644
index 00000000..12d93c54
--- /dev/null
+++ b/cmds-inspect-dump-super.c
@@ -0,0 +1,536 @@
+/*
+ * 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.
+ */
+
+#include "kerncompat.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <uuid/uuid.h>
+#include <errno.h>
+
+#include "ctree.h"
+#include "disk-io.h"
+#include "print-tree.h"
+#include "transaction.h"
+#include "list.h"
+#include "utils.h"
+#include "commands.h"
+#include "crc32c.h"
+#include "cmds-inspect-dump-super.h"
+
+static int check_csum_sblock(void *sb, int csum_size)
+{
+	char result[BTRFS_CSUM_SIZE];
+	u32 crc = ~(u32)0;
+
+	crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE,
+				crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
+	btrfs_csum_final(crc, result);
+
+	return !memcmp(sb, &result, csum_size);
+}
+
+static void print_sys_chunk_array(struct btrfs_super_block *sb)
+{
+	struct extent_buffer *buf;
+	struct btrfs_disk_key *disk_key;
+	struct btrfs_chunk *chunk;
+	u8 *array_ptr;
+	unsigned long sb_array_offset;
+	u32 num_stripes;
+	u32 array_size;
+	u32 len = 0;
+	u32 cur_offset;
+	struct btrfs_key key;
+	int item;
+
+	buf = malloc(sizeof(*buf) + sizeof(*sb));
+	if (!buf) {
+		fprintf(stderr, "%s\n", strerror(ENOMEM));
+		goto out;
+	}
+	write_extent_buffer(buf, sb, 0, sizeof(*sb));
+	array_size = btrfs_super_sys_array_size(sb);
+
+	array_ptr = sb->sys_chunk_array;
+	sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
+	cur_offset = 0;
+	item = 0;
+
+	while (cur_offset < array_size) {
+		disk_key = (struct btrfs_disk_key *)array_ptr;
+		len = sizeof(*disk_key);
+		if (cur_offset + len > array_size)
+			goto out_short_read;
+
+		btrfs_disk_key_to_cpu(&key, disk_key);
+
+		array_ptr += len;
+		sb_array_offset += len;
+		cur_offset += len;
+
+		printf("\titem %d ", item);
+		btrfs_print_key(disk_key);
+		putchar('\n');
+
+		if (key.type == BTRFS_CHUNK_ITEM_KEY) {
+			chunk = (struct btrfs_chunk *)sb_array_offset;
+			/*
+			 * At least one btrfs_chunk with one stripe must be
+			 * present, exact stripe count check comes afterwards
+			 */
+			len = btrfs_chunk_item_size(1);
+			if (cur_offset + len > array_size)
+				goto out_short_read;
+
+			print_chunk(buf, chunk);
+			num_stripes = btrfs_chunk_num_stripes(buf, chunk);
+			if (!num_stripes) {
+				printk(
+	    "ERROR: invalid number of stripes %u in sys_array at offset %u\n",
+					num_stripes, cur_offset);
+				break;
+			}
+			len = btrfs_chunk_item_size(num_stripes);
+			if (cur_offset + len > array_size)
+				goto out_short_read;
+		} else {
+			printk(
+		"ERROR: unexpected item type %u in sys_array at offset %u\n",
+				(u32)key.type, cur_offset);
+			break;
+		}
+		array_ptr += len;
+		sb_array_offset += len;
+		cur_offset += len;
+
+		item++;
+	}
+
+	free(buf);
+out:
+	return;
+
+out_short_read:
+	printk("ERROR: sys_array too short to read %u bytes at offset %u\n",
+			len, cur_offset);
+	free(buf);
+}
+
+static int empty_backup(struct btrfs_root_backup *backup)
+{
+	if (backup == NULL ||
+		(backup->tree_root == 0 &&
+		 backup->tree_root_gen == 0))
+		return 1;
+	return 0;
+}
+
+static void print_root_backup(struct btrfs_root_backup *backup)
+{
+	printf("\t\tbackup_tree_root:\t%llu\tgen: %llu\tlevel: %d\n",
+			btrfs_backup_tree_root(backup),
+			btrfs_backup_tree_root_gen(backup),
+			btrfs_backup_tree_root_level(backup));
+	printf("\t\tbackup_chunk_root:\t%llu\tgen: %llu\tlevel: %d\n",
+			btrfs_backup_chunk_root(backup),
+			btrfs_backup_chunk_root_gen(backup),
+			btrfs_backup_chunk_root_level(backup));
+	printf("\t\tbackup_extent_root:\t%llu\tgen: %llu\tlevel: %d\n",
+			btrfs_backup_extent_root(backup),
+			btrfs_backup_extent_root_gen(backup),
+			btrfs_backup_extent_root_level(backup));
+	printf("\t\tbackup_fs_root:\t\t%llu\tgen: %llu\tlevel: %d\n",
+			btrfs_backup_fs_root(backup),
+			btrfs_backup_fs_root_gen(backup),
+			btrfs_backup_fs_root_level(backup));
+	printf("\t\tbackup_dev_root:\t%llu\tgen: %llu\tlevel: %d\n",
+			btrfs_backup_dev_root(backup),
+			btrfs_backup_dev_root_gen(backup),
+			btrfs_backup_dev_root_level(backup));
+	printf("\t\tbackup_csum_root:\t%llu\tgen: %llu\tlevel: %d\n",
+			btrfs_backup_csum_root(backup),
+			btrfs_backup_csum_root_gen(backup),
+			btrfs_backup_csum_root_level(backup));
+
+	printf("\t\tbackup_total_bytes:\t%llu\n",
+					btrfs_backup_total_bytes(backup));
+	printf("\t\tbackup_bytes_used:\t%llu\n",
+					btrfs_backup_bytes_used(backup));
+	printf("\t\tbackup_num_devices:\t%llu\n",
+					btrfs_backup_num_devices(backup));
+	putchar('\n');
+}
+
+static void print_backup_roots(struct btrfs_super_block *sb)
+{
+	struct btrfs_root_backup *backup;
+	int i;
+
+	for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
+		backup = sb->super_roots + i;
+		if (!empty_backup(backup)) {
+			printf("\tbackup %d:\n", i);
+			print_root_backup(backup);
+		}
+	}
+}
+
+struct readable_flag_entry {
+	u64 bit;
+	char *output;
+};
+
+#define DEF_INCOMPAT_FLAG_ENTRY(bit_name)		\
+	{BTRFS_FEATURE_INCOMPAT_##bit_name, #bit_name}
+
+static struct readable_flag_entry incompat_flags_array[] = {
+	DEF_INCOMPAT_FLAG_ENTRY(MIXED_BACKREF),
+	DEF_INCOMPAT_FLAG_ENTRY(DEFAULT_SUBVOL),
+	DEF_INCOMPAT_FLAG_ENTRY(MIXED_GROUPS),
+	DEF_INCOMPAT_FLAG_ENTRY(COMPRESS_LZO),
+	DEF_INCOMPAT_FLAG_ENTRY(COMPRESS_LZOv2),
+	DEF_INCOMPAT_FLAG_ENTRY(BIG_METADATA),
+	DEF_INCOMPAT_FLAG_ENTRY(EXTENDED_IREF),
+	DEF_INCOMPAT_FLAG_ENTRY(RAID56),
+	DEF_INCOMPAT_FLAG_ENTRY(SKINNY_METADATA),
+	DEF_INCOMPAT_FLAG_ENTRY(NO_HOLES)
+};
+static const int incompat_flags_num = sizeof(incompat_flags_array) /
+				      sizeof(struct readable_flag_entry);
+
+#define DEF_HEADER_FLAG_ENTRY(bit_name)			\
+	{BTRFS_HEADER_FLAG_##bit_name, #bit_name}
+#define DEF_SUPER_FLAG_ENTRY(bit_name)			\
+	{BTRFS_SUPER_FLAG_##bit_name, #bit_name}
+
+static struct readable_flag_entry super_flags_array[] = {
+	DEF_HEADER_FLAG_ENTRY(WRITTEN),
+	DEF_HEADER_FLAG_ENTRY(RELOC),
+	DEF_SUPER_FLAG_ENTRY(CHANGING_FSID),
+	DEF_SUPER_FLAG_ENTRY(SEEDING),
+	DEF_SUPER_FLAG_ENTRY(METADUMP),
+	DEF_SUPER_FLAG_ENTRY(METADUMP_V2)
+};
+static const int super_flags_num = ARRAY_SIZE(super_flags_array);
+
+#define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
+				 BTRFS_HEADER_FLAG_RELOC |\
+				 BTRFS_SUPER_FLAG_CHANGING_FSID |\
+				 BTRFS_SUPER_FLAG_SEEDING |\
+				 BTRFS_SUPER_FLAG_METADUMP |\
+				 BTRFS_SUPER_FLAG_METADUMP_V2)
+
+static void __print_readable_flag(u64 flag, struct readable_flag_entry *array,
+				  int array_size, u64 supported_flags)
+{
+	int i;
+	int first = 1;
+	struct readable_flag_entry *entry;
+
+	if (!flag)
+		return;
+
+	printf("\t\t\t( ");
+	for (i = 0; i < array_size; i++) {
+		entry = array + i;
+		if (flag & entry->bit) {
+			if (first)
+				printf("%s ", entry->output);
+			else
+				printf("|\n\t\t\t  %s ", entry->output);
+			first = 0;
+		}
+	}
+	flag &= ~supported_flags;
+	if (flag) {
+		if (first)
+			printf("unknown flag: 0x%llx ", flag);
+		else
+			printf("|\n\t\t\t  unknown flag: 0x%llx ", flag);
+	}
+	printf(")\n");
+}
+
+static void print_readable_incompat_flag(u64 flag)
+{
+	return __print_readable_flag(flag, incompat_flags_array,
+				     incompat_flags_num,
+				     BTRFS_FEATURE_INCOMPAT_SUPP);
+}
+
+static void print_readable_super_flag(u64 flag)
+{
+	return __print_readable_flag(flag, super_flags_array,
+				     super_flags_num, BTRFS_SUPER_FLAG_SUPP);
+}
+
+static void dump_superblock(struct btrfs_super_block *sb, int full)
+{
+	int i;
+	char *s, buf[BTRFS_UUID_UNPARSED_SIZE];
+	u8 *p;
+
+	printf("csum\t\t\t0x");
+	for (i = 0, p = sb->csum; i < btrfs_super_csum_size(sb); i++)
+		printf("%02x", p[i]);
+	if (check_csum_sblock(sb, btrfs_super_csum_size(sb)))
+		printf(" [match]");
+	else
+		printf(" [DON'T MATCH]");
+	putchar('\n');
+
+	printf("bytenr\t\t\t%llu\n",
+		(unsigned long long)btrfs_super_bytenr(sb));
+	printf("flags\t\t\t0x%llx\n",
+		(unsigned long long)btrfs_super_flags(sb));
+	print_readable_super_flag(btrfs_super_flags(sb));
+
+	printf("magic\t\t\t");
+	s = (char *) &sb->magic;
+	for (i = 0; i < 8; i++)
+		putchar(isprint(s[i]) ? s[i] : '.');
+	if (btrfs_super_magic(sb) == BTRFS_MAGIC)
+		printf(" [match]\n");
+	else
+		printf(" [DON'T MATCH]\n");
+
+	uuid_unparse(sb->fsid, buf);
+	printf("fsid\t\t\t%s\n", buf);
+
+	printf("label\t\t\t");
+	s = sb->label;
+	for (i = 0; i < BTRFS_LABEL_SIZE && s[i]; i++)
+		putchar(isprint(s[i]) ? s[i] : '.');
+	putchar('\n');
+
+	printf("generation\t\t%llu\n",
+	       (unsigned long long)btrfs_super_generation(sb));
+	printf("root\t\t\t%llu\n", (unsigned long long)btrfs_super_root(sb));
+	printf("sys_array_size\t\t%llu\n",
+	       (unsigned long long)btrfs_super_sys_array_size(sb));
+	printf("chunk_root_generation\t%llu\n",
+	       (unsigned long long)btrfs_super_chunk_root_generation(sb));
+	printf("root_level\t\t%llu\n",
+	       (unsigned long long)btrfs_super_root_level(sb));
+	printf("chunk_root\t\t%llu\n",
+	       (unsigned long long)btrfs_super_chunk_root(sb));
+	printf("chunk_root_level\t%llu\n",
+	       (unsigned long long)btrfs_super_chunk_root_level(sb));
+	printf("log_root\t\t%llu\n",
+	       (unsigned long long)btrfs_super_log_root(sb));
+	printf("log_root_transid\t%llu\n",
+	       (unsigned long long)btrfs_super_log_root_transid(sb));
+	printf("log_root_level\t\t%llu\n",
+	       (unsigned long long)btrfs_super_log_root_level(sb));
+	printf("total_bytes\t\t%llu\n",
+	       (unsigned long long)btrfs_super_total_bytes(sb));
+	printf("bytes_used\t\t%llu\n",
+	       (unsigned long long)btrfs_super_bytes_used(sb));
+	printf("sectorsize\t\t%llu\n",
+	       (unsigned long long)btrfs_super_sectorsize(sb));
+	printf("nodesize\t\t%llu\n",
+	       (unsigned long long)btrfs_super_nodesize(sb));
+	printf("leafsize\t\t%llu\n",
+	       (unsigned long long)btrfs_super_leafsize(sb));
+	printf("stripesize\t\t%llu\n",
+	       (unsigned long long)btrfs_super_stripesize(sb));
+	printf("root_dir\t\t%llu\n",
+	       (unsigned long long)btrfs_super_root_dir(sb));
+	printf("num_devices\t\t%llu\n",
+	       (unsigned long long)btrfs_super_num_devices(sb));
+	printf("compat_flags\t\t0x%llx\n",
+	       (unsigned long long)btrfs_super_compat_flags(sb));
+	printf("compat_ro_flags\t\t0x%llx\n",
+	       (unsigned long long)btrfs_super_compat_ro_flags(sb));
+	printf("incompat_flags\t\t0x%llx\n",
+	       (unsigned long long)btrfs_super_incompat_flags(sb));
+	print_readable_incompat_flag(btrfs_super_incompat_flags(sb));
+	printf("csum_type\t\t%llu\n",
+	       (unsigned long long)btrfs_super_csum_type(sb));
+	printf("csum_size\t\t%llu\n",
+	       (unsigned long long)btrfs_super_csum_size(sb));
+	printf("cache_generation\t%llu\n",
+	       (unsigned long long)btrfs_super_cache_generation(sb));
+	printf("uuid_tree_generation\t%llu\n",
+	       (unsigned long long)btrfs_super_uuid_tree_generation(sb));
+
+	uuid_unparse(sb->dev_item.uuid, buf);
+	printf("dev_item.uuid\t\t%s\n", buf);
+
+	uuid_unparse(sb->dev_item.fsid, buf);
+	printf("dev_item.fsid\t\t%s %s\n", buf,
+		!memcmp(sb->dev_item.fsid, sb->fsid, BTRFS_FSID_SIZE) ?
+			"[match]" : "[DON'T MATCH]");
+
+	printf("dev_item.type\t\t%llu\n", (unsigned long long)
+	       btrfs_stack_device_type(&sb->dev_item));
+	printf("dev_item.total_bytes\t%llu\n", (unsigned long long)
+	       btrfs_stack_device_total_bytes(&sb->dev_item));
+	printf("dev_item.bytes_used\t%llu\n", (unsigned long long)
+	       btrfs_stack_device_bytes_used(&sb->dev_item));
+	printf("dev_item.io_align\t%u\n", (unsigned int)
+	       btrfs_stack_device_io_align(&sb->dev_item));
+	printf("dev_item.io_width\t%u\n", (unsigned int)
+	       btrfs_stack_device_io_width(&sb->dev_item));
+	printf("dev_item.sector_size\t%u\n", (unsigned int)
+	       btrfs_stack_device_sector_size(&sb->dev_item));
+	printf("dev_item.devid\t\t%llu\n",
+	       btrfs_stack_device_id(&sb->dev_item));
+	printf("dev_item.dev_group\t%u\n", (unsigned int)
+	       btrfs_stack_device_group(&sb->dev_item));
+	printf("dev_item.seek_speed\t%u\n", (unsigned int)
+	       btrfs_stack_device_seek_speed(&sb->dev_item));
+	printf("dev_item.bandwidth\t%u\n", (unsigned int)
+	       btrfs_stack_device_bandwidth(&sb->dev_item));
+	printf("dev_item.generation\t%llu\n", (unsigned long long)
+	       btrfs_stack_device_generation(&sb->dev_item));
+	if (full) {
+		printf("sys_chunk_array[%d]:\n", BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
+		print_sys_chunk_array(sb);
+		printf("backup_roots[%d]:\n", BTRFS_NUM_BACKUP_ROOTS);
+		print_backup_roots(sb);
+	}
+}
+
+static int load_and_dump_sb(char *filename, int fd, u64 sb_bytenr, int full,
+		int force)
+{
+	u8 super_block_data[BTRFS_SUPER_INFO_SIZE];
+	struct btrfs_super_block *sb;
+	u64 ret;
+
+	sb = (struct btrfs_super_block *)super_block_data;
+
+	ret = pread64(fd, super_block_data, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
+	if (ret != BTRFS_SUPER_INFO_SIZE) {
+		/* check if the disk if too short for further superblock */
+		if (ret == 0 && errno == 0)
+			return 0;
+
+		fprintf(stderr,
+		   "ERROR: Failed to read the superblock on %s at %llu\n",
+		   filename, (unsigned long long)sb_bytenr);
+		fprintf(stderr,
+		   "ERROR: error = '%s', errno = %d\n", strerror(errno), errno);
+		return 1;
+	}
+	printf("superblock: bytenr=%llu, device=%s\n", sb_bytenr, filename);
+	printf("---------------------------------------------------------\n");
+	if (btrfs_super_magic(sb) != BTRFS_MAGIC && !force) {
+		fprintf(stderr,
+		    "ERROR: bad magic on superblock on %s at %llu\n",
+		    filename, (unsigned long long)sb_bytenr);
+	} else {
+		dump_superblock(sb, full);
+	}
+	return 0;
+}
+
+const char * const cmd_inspect_dump_super_usage[] = {
+	"btrfs inspect-internal dump-super [options] device [device...]",
+	"Dump superblock from a device",
+	"-f                  print full superblock information",
+	"-a                  print information of all superblocks",
+	"-i <super_mirror>   specify which mirror to print out",
+	"-F                  attempt to dump superblocks with bad magic",
+	"-s <bytenr>         specify alternate superblock offset",
+	NULL
+};
+
+int cmd_inspect_dump_super(int argc, char **argv)
+{
+	int opt;
+	int all = 0;
+	int full = 0;
+	int force = 0;
+	char *filename;
+	int fd = -1;
+	int i;
+	int ret = 0;
+	u64 arg;
+	u64 sb_bytenr = btrfs_sb_offset(0);
+
+	while ((opt = getopt(argc, argv, "fFai:s:")) != -1) {
+		switch (opt) {
+		case 'i':
+			arg = arg_strtou64(optarg);
+			if (arg >= BTRFS_SUPER_MIRROR_MAX) {
+				fprintf(stderr,
+					"Illegal super_mirror %llu\n",
+					arg);
+				usage(cmd_inspect_dump_super_usage);
+			}
+			sb_bytenr = btrfs_sb_offset(arg);
+			break;
+
+		case 'a':
+			all = 1;
+			break;
+		case 'f':
+			full = 1;
+			break;
+		case 'F':
+			force = 1;
+			break;
+		case 's':
+			sb_bytenr = arg_strtou64(optarg);
+			all = 0;
+			break;
+		default:
+			usage(cmd_inspect_dump_super_usage);
+		}
+	}
+
+	if (check_argc_min(argc - optind, 1))
+		usage(cmd_inspect_dump_super_usage);
+
+	for (i = optind; i < argc; i++) {
+		filename = argv[i];
+		fd = open(filename, O_RDONLY, 0666);
+		if (fd < 0) {
+			fprintf(stderr, "Could not open %s\n", filename);
+			ret = 1;
+			goto out;
+		}
+
+		if (all) {
+			int idx;
+
+			for (idx = 0; idx < BTRFS_SUPER_MIRROR_MAX; idx++) {
+				sb_bytenr = btrfs_sb_offset(idx);
+				if (load_and_dump_sb(filename, fd,
+						sb_bytenr, full, force)) {
+					close(fd);
+					ret = 1;
+					goto out;
+				}
+
+				putchar('\n');
+			}
+		} else {
+			load_and_dump_sb(filename, fd, sb_bytenr, full, force);
+			putchar('\n');
+		}
+		close(fd);
+	}
+
+out:
+	return ret;
+}
diff --git a/cmds-inspect-dump-super.h b/cmds-inspect-dump-super.h
new file mode 100644
index 00000000..86472ef0
--- /dev/null
+++ b/cmds-inspect-dump-super.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2012 STRATO AG.  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.
+ */
+
+#ifndef __CMDS_INSPECT_DUMP_SUPER_H__
+#define __CMDS_INSPECT_DUMP_SUPER_H__
+
+int cmd_inspect_dump_super(int ac, char **av);
+
+extern const char * const cmd_inspect_dump_super_usage[];
+
+#endif
diff --git a/cmds-inspect.c b/cmds-inspect.c
index 25ddd4cf..176f8360 100644
--- a/cmds-inspect.c
+++ b/cmds-inspect.c
@@ -32,6 +32,7 @@
 #include "commands.h"
 #include "btrfs-list.h"
 #include "cmds-inspect-dump-tree.h"
+#include "cmds-inspect-dump-super.h"
 
 static const char * const inspect_cmd_group_usage[] = {
 	"btrfs inspect-internal <command> <args>",
@@ -625,6 +626,11 @@ static int cmd_inspect_dump_tree_hook(int ac, char **av)
 	return cmd_inspect_dump_tree(ac, av);
 }
 
+static int cmd_inspect_dump_super_hook(int ac, char **av)
+{
+	return cmd_inspect_dump_super(ac, av);
+}
+
 static const char inspect_cmd_group_info[] =
 "query various internal information";
 
@@ -642,6 +648,8 @@ const struct cmd_group inspect_cmd_group = {
 			cmd_inspect_min_dev_size_usage, NULL, 0 },
 		{ "dump-tree", cmd_inspect_dump_tree_hook,
 				cmd_inspect_dump_tree_usage, NULL, 0 },
+		{ "dump-super", cmd_inspect_dump_super_hook,
+				cmd_inspect_dump_super_usage, NULL, 0 },
 		NULL_CMD_STRUCT
 	}
 };