[v5,2/4] e2image: add -b and -B options to use supperblock backup

Message ID 20180526224600.46905-3-artem.blagodarenko@gmail.com
State Superseded
Headers show
Series
  • [v5,1/4] ext2fs: opening filesystem code refactoring
Related show

Commit Message

c17828 May 26, 2018, 10:45 p.m.
e2image has no ability to use superblock backup to copy metadata.
This feature can be useful if someone wants to make partition
image and fix it using e2fsck utility.

New -b option allows to pass superblock number, like e2fsck utility do.
e2image doesn't change primary superblock and store is as is, so
it can be fixed using e2fsck latter. Option -B allows to set
superblock size.

Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
 misc/e2image.8.in | 33 +++++++++++++++++++++++++++++++++
 misc/e2image.c    | 43 +++++++++++++++++++++++++++++++++++++------
 2 files changed, 70 insertions(+), 6 deletions(-)

Comments

Andreas Dilger June 4, 2018, 5:44 p.m. | #1
> On May 26, 2018, at 4:45 PM, Artem Blagodarenko <artem.blagodarenko@gmail.com> wrote:
> 
> e2image has no ability to use superblock backup to copy metadata.
> This feature can be useful if someone wants to make partition
> image and fix it using e2fsck utility.
> 
> New -b option allows to pass superblock number, like e2fsck utility do.
> e2image doesn't change primary superblock and store is as is, so
> it can be fixed using e2fsck latter. Option -B allows to set
> superblock size.
> 
> Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>

Reviewed-by: Andreas Dilger <adilger@dilger.ca>

> ---
> misc/e2image.8.in | 33 +++++++++++++++++++++++++++++++++
> misc/e2image.c    | 43 +++++++++++++++++++++++++++++++++++++------
> 2 files changed, 70 insertions(+), 6 deletions(-)
> 
> diff --git a/misc/e2image.8.in b/misc/e2image.8.in
> index a7bfdf24..bbbb57ae 100644
> --- a/misc/e2image.8.in
> +++ b/misc/e2image.8.in
> @@ -12,6 +12,15 @@ e2image \- Save critical ext2/ext3/ext4 filesystem metadata to a file
> ]
> [
> .B \-f
> +.B \-b
> +.I superblock
> +]
> +[
> +.B \-B
> +.I blocksize
> +]
> +[
> +.B \-fr
> ]
> .I device
> .I image-file
> @@ -167,6 +176,22 @@ the
> option will prevent analysis of problems related to hash-tree indexed
> directories.
> .PP
> +Option
> +.B \-b
> +.I superblock
> +can be used to get image from partition with broken primary superblock.
> +The partition is copied as-is including broken primary superblock.
> +.PP
> +Option
> +.B \-B
> +.I blocksize
> +can be used to set superblock block size. Normally, e2fsck will search
> +for the superblock at various different block sizes in an attempt to find
> +the appropriate blocksize. This search can be fooled in some cases.  This
> +option forces e2fsck to only try locating the superblock at a particular
> +blocksize. If the superblock is not found, e2fsck will terminate with a
> +fatal error.
> +.PP
> Note that this will work even if you substitute "/dev/hda1" for another raw
> disk image, or QCOW2 image previously created by
> .BR e2image .
> @@ -217,6 +242,14 @@ This can be useful to write a qcow2 image containing all data to a
> sparse image file where it can be loop mounted, or to a disk partition.
> Note that this may not work with qcow2 images not generated by e2image.
> .PP
> +Options
> +.B \-b
> +.I superblock
> +and
> +.B \-B
> +.I blocksize
> +can be used same way as for raw images.
> +.PP
> .SH INCLUDING DATA
> Normally
> .B e2image
> diff --git a/misc/e2image.c b/misc/e2image.c
> index 83ae6335..727e3876 100644
> --- a/misc/e2image.c
> +++ b/misc/e2image.c
> @@ -104,7 +104,8 @@ static int get_bits_from_size(size_t size)
> 
> static void usage(void)
> {
> -	fprintf(stderr, _("Usage: %s [ -r|Q ] [ -f ] device image-file\n"),
> +	fprintf(stderr, _("Usage: %s [ -r|Q ] [ -f ] [ -b superblock ] [ -B blocksize]"
> +			  "[ -fr ] device image-file\n"),
> 		program_name);
> 	fprintf(stderr, _("       %s -I device image-file\n"), program_name);
> 	fprintf(stderr, _("       %s -ra  [  -cfnp  ] [ -o src_offset ] "
> @@ -1256,7 +1257,8 @@ static void output_qcow2_meta_data_blocks(ext2_filsys fs, int fd)
> 	free_qcow2_image(img);
> }
> 
> -static void write_raw_image_file(ext2_filsys fs, int fd, int type, int flags)
> +static void write_raw_image_file(ext2_filsys fs, int fd, int type, int flags,
> +				 blk64_t superblock)
> {
> 	struct process_block_struct	pb;
> 	struct ext2_inode		inode;
> @@ -1284,6 +1286,22 @@ static void write_raw_image_file(ext2_filsys fs, int fd, int type, int flags)
> 		}
> 	}
> 
> +	if (superblock) {
> +		int j;
> +
> +		ext2fs_mark_block_bitmap2(meta_block_map, superblock);
> +		meta_blocks_count++;
> +
> +		/*
> +		 * Mark the backup superblock descriptors
> +		 */
> +		for (j = 0; j < fs->desc_blocks; j++) {
> +			ext2fs_mark_block_bitmap2(meta_block_map,
> +			ext2fs_descriptor_block_loc2(fs, superblock, j));
> +		}
> +		meta_blocks_count += fs->desc_blocks;
> +	}
> +
> 	mark_table_blocks(fs);
> 	if (show_progress)
> 		fprintf(stderr, "%s", _("Scanning inodes...\n"));
> @@ -1463,6 +1481,8 @@ int main (int argc, char ** argv)
> 	int ignore_rw_mount = 0;
> 	int check = 0;
> 	struct stat st;
> +	blk64_t superblock = 0;
> +	int blocksize = 0;
> 
> #ifdef ENABLE_NLS
> 	setlocale(LC_MESSAGES, "");
> @@ -1476,8 +1496,14 @@ int main (int argc, char ** argv)
> 	if (argc && *argv)
> 		program_name = *argv;
> 	add_error_table(&et_ext2_error_table);
> -	while ((c = getopt(argc, argv, "nrsIQafo:O:pc")) != EOF)
> +	while ((c = getopt(argc, argv, "b:B:nrsIQafo:O:pc")) != EOF)
> 		switch (c) {
> +		case 'b':
> +			superblock = strtoull(optarg, NULL, 0);
> +			break;
> +		case 'B':
> +			blocksize = strtoul(optarg, NULL, 0);
> +			break;
> 		case 'I':
> 			flags |= E2IMAGE_INSTALL_FLAG;
> 			break;
> @@ -1529,6 +1555,11 @@ int main (int argc, char ** argv)
> 						 "with raw or QCOW2 images."));
> 		exit(1);
> 	}
> +	if (superblock && !img_type) {
> +		com_err(program_name, 0, "%s", _("-b option can only be used "
> +						 "with raw or QCOW2 images."));
> +		exit(1);
> +	}
> 	if ((source_offset || dest_offset) && img_type != E2IMAGE_RAW) {
> 		com_err(program_name, 0, "%s",
> 			_("Offsets are only allowed with raw images."));
> @@ -1579,8 +1610,8 @@ int main (int argc, char ** argv)
> 		}
> 	}
> 	sprintf(offset_opt, "offset=%llu", source_offset);
> -	retval = ext2fs_open2(device_name, offset_opt, open_flag, 0, 0,
> -			      unix_io_manager, &fs);
> +	retval = ext2fs_open2(device_name, offset_opt, open_flag,
> +			      superblock, blocksize, unix_io_manager, &fs);
>         if (retval) {
> 		com_err (program_name, retval, _("while trying to open %s"),
> 			 device_name);
> @@ -1665,7 +1696,7 @@ skip_device:
> 		exit(1);
> 	}
> 	if (img_type)
> -		write_raw_image_file(fs, fd, img_type, flags);
> +		write_raw_image_file(fs, fd, img_type, flags, superblock);
> 	else
> 		write_image_file(fs, fd);
> 
> --
> 2.14.3
> 


Cheers, Andreas

Patch

diff --git a/misc/e2image.8.in b/misc/e2image.8.in
index a7bfdf24..bbbb57ae 100644
--- a/misc/e2image.8.in
+++ b/misc/e2image.8.in
@@ -12,6 +12,15 @@  e2image \- Save critical ext2/ext3/ext4 filesystem metadata to a file
 ]
 [
 .B \-f
+.B \-b
+.I superblock
+]
+[
+.B \-B
+.I blocksize
+]
+[
+.B \-fr
 ]
 .I device
 .I image-file
@@ -167,6 +176,22 @@  the
 option will prevent analysis of problems related to hash-tree indexed
 directories.
 .PP
+Option
+.B \-b
+.I superblock
+can be used to get image from partition with broken primary superblock.
+The partition is copied as-is including broken primary superblock.
+.PP
+Option
+.B \-B
+.I blocksize
+can be used to set superblock block size. Normally, e2fsck will search
+for the superblock at various different block sizes in an attempt to find
+the appropriate blocksize. This search can be fooled in some cases.  This
+option forces e2fsck to only try locating the superblock at a particular
+blocksize. If the superblock is not found, e2fsck will terminate with a
+fatal error.
+.PP
 Note that this will work even if you substitute "/dev/hda1" for another raw
 disk image, or QCOW2 image previously created by
 .BR e2image .
@@ -217,6 +242,14 @@  This can be useful to write a qcow2 image containing all data to a
 sparse image file where it can be loop mounted, or to a disk partition.
 Note that this may not work with qcow2 images not generated by e2image.
 .PP
+Options
+.B \-b
+.I superblock
+and
+.B \-B
+.I blocksize
+can be used same way as for raw images.
+.PP
 .SH INCLUDING DATA
 Normally
 .B e2image
diff --git a/misc/e2image.c b/misc/e2image.c
index 83ae6335..727e3876 100644
--- a/misc/e2image.c
+++ b/misc/e2image.c
@@ -104,7 +104,8 @@  static int get_bits_from_size(size_t size)
 
 static void usage(void)
 {
-	fprintf(stderr, _("Usage: %s [ -r|Q ] [ -f ] device image-file\n"),
+	fprintf(stderr, _("Usage: %s [ -r|Q ] [ -f ] [ -b superblock ] [ -B blocksize]"
+			  "[ -fr ] device image-file\n"),
 		program_name);
 	fprintf(stderr, _("       %s -I device image-file\n"), program_name);
 	fprintf(stderr, _("       %s -ra  [  -cfnp  ] [ -o src_offset ] "
@@ -1256,7 +1257,8 @@  static void output_qcow2_meta_data_blocks(ext2_filsys fs, int fd)
 	free_qcow2_image(img);
 }
 
-static void write_raw_image_file(ext2_filsys fs, int fd, int type, int flags)
+static void write_raw_image_file(ext2_filsys fs, int fd, int type, int flags,
+				 blk64_t superblock)
 {
 	struct process_block_struct	pb;
 	struct ext2_inode		inode;
@@ -1284,6 +1286,22 @@  static void write_raw_image_file(ext2_filsys fs, int fd, int type, int flags)
 		}
 	}
 
+	if (superblock) {
+		int j;
+
+		ext2fs_mark_block_bitmap2(meta_block_map, superblock);
+		meta_blocks_count++;
+
+		/*
+		 * Mark the backup superblock descriptors
+		 */
+		for (j = 0; j < fs->desc_blocks; j++) {
+			ext2fs_mark_block_bitmap2(meta_block_map,
+			ext2fs_descriptor_block_loc2(fs, superblock, j));
+		}
+		meta_blocks_count += fs->desc_blocks;
+	}
+
 	mark_table_blocks(fs);
 	if (show_progress)
 		fprintf(stderr, "%s", _("Scanning inodes...\n"));
@@ -1463,6 +1481,8 @@  int main (int argc, char ** argv)
 	int ignore_rw_mount = 0;
 	int check = 0;
 	struct stat st;
+	blk64_t superblock = 0;
+	int blocksize = 0;
 
 #ifdef ENABLE_NLS
 	setlocale(LC_MESSAGES, "");
@@ -1476,8 +1496,14 @@  int main (int argc, char ** argv)
 	if (argc && *argv)
 		program_name = *argv;
 	add_error_table(&et_ext2_error_table);
-	while ((c = getopt(argc, argv, "nrsIQafo:O:pc")) != EOF)
+	while ((c = getopt(argc, argv, "b:B:nrsIQafo:O:pc")) != EOF)
 		switch (c) {
+		case 'b':
+			superblock = strtoull(optarg, NULL, 0);
+			break;
+		case 'B':
+			blocksize = strtoul(optarg, NULL, 0);
+			break;
 		case 'I':
 			flags |= E2IMAGE_INSTALL_FLAG;
 			break;
@@ -1529,6 +1555,11 @@  int main (int argc, char ** argv)
 						 "with raw or QCOW2 images."));
 		exit(1);
 	}
+	if (superblock && !img_type) {
+		com_err(program_name, 0, "%s", _("-b option can only be used "
+						 "with raw or QCOW2 images."));
+		exit(1);
+	}
 	if ((source_offset || dest_offset) && img_type != E2IMAGE_RAW) {
 		com_err(program_name, 0, "%s",
 			_("Offsets are only allowed with raw images."));
@@ -1579,8 +1610,8 @@  int main (int argc, char ** argv)
 		}
 	}
 	sprintf(offset_opt, "offset=%llu", source_offset);
-	retval = ext2fs_open2(device_name, offset_opt, open_flag, 0, 0,
-			      unix_io_manager, &fs);
+	retval = ext2fs_open2(device_name, offset_opt, open_flag,
+			      superblock, blocksize, unix_io_manager, &fs);
         if (retval) {
 		com_err (program_name, retval, _("while trying to open %s"),
 			 device_name);
@@ -1665,7 +1696,7 @@  skip_device:
 		exit(1);
 	}
 	if (img_type)
-		write_raw_image_file(fs, fd, img_type, flags);
+		write_raw_image_file(fs, fd, img_type, flags, superblock);
 	else
 		write_image_file(fs, fd);