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Date: Mon, 4 Dec 2017 22:35:28 +0300
From: Artem Blagodarenko <artem.blagodarenko@...il.com>
To: linux-ext4@...r.kernel.org
Cc: adilger.kernel@...ger.ca,
Artem Blagodarenko <artem.blagodarenko@...gate.com>
Subject: [PATCH v3 2/4] e2image: add -b option to use supperblock backup
From: Artem Blagodarenko <artem.blagodarenko@...gate.com>
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.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@...il.com>
---
misc/e2image.8.in | 32 ++++++++++++++++++++++++++++++++
misc/e2image.c | 44 ++++++++++++++++++++++++++++++++++++++------
2 files changed, 70 insertions(+), 6 deletions(-)
diff --git a/misc/e2image.8.in b/misc/e2image.8.in
index f28a76ea..d6125bb4 100644
--- a/misc/e2image.8.in
+++ b/misc/e2image.8.in
@@ -11,6 +11,14 @@ e2image \- Save critical ext2/ext3/ext4 filesystem metadata to a file
.B \-r|Q
]
[
+.B \-b
+.I superblock
+]
+[
+.B \-B
+.I blocksize
+]
+[
.B \-fr
]
.I device
@@ -167,6 +175,22 @@ 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 +241,14 @@ 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 be001f0f..b1b7a17d 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 ] [ -fr ] device image-file\n"),
+ fprintf(stderr, _("Usage: %s [ -r|Q ] [ -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 +1610,9 @@ 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 +1697,7 @@ 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);
--
2.13.6 (Apple Git-96)
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