Currently we only attempt to wipe old raid signatures at the end of the
device. However this might not be enough because some file system
(btrfs) may still have their signatures on the device which can be
confusing for userspace possibly resulting in the unmountable file
system.
This patch adds a function which uses libblkid library to wipe all the
signatures from the device. In case that libblkid lack the capability to
do so we still use the old method of wiping off raid signatures and new
method of wiping btrfs signatures (originally written by Eric Sandeed).
We attempt to wipe off signatures before creating the file system.
Information about existing signatures is printed only in verbose mode.
Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
---
configure | 2 +-
configure.in | 1 +
lib/config.h.in | 3 +
misc/mke2fs.c | 210 +++++++++++++++++++++++++++++++++++++++++++++----------
4 files changed, 178 insertions(+), 38 deletions(-)
diff --git a/configure b/configure
index 5b91c01..8059f06 100755
--- a/configure
+++ b/configure
@@ -11091,7 +11091,7 @@ if test "$ac_res" != no; then :
fi
fi
-for ac_func in __secure_getenv backtrace blkid_probe_get_topology chflags fallocate fallocate64 fchown fdatasync fstat64 ftruncate64 getdtablesize getmntinfo getpwuid_r getrlimit getrusage jrand48 llseek lseek64 mallinfo mbstowcs memalign mmap msync nanosleep open64 pathconf posix_fadvise posix_memalign prctl setmntent setresgid setresuid srandom strcasecmp strdup strnlen strptime strtoull sync_file_range sysconf usleep utime valloc
+for ac_func in __secure_getenv backtrace blkid_probe_get_topology blkid_probe_step_back chflags fallocate fallocate64 fchown fdatasync fstat64 ftruncate64 getdtablesize getmntinfo getpwuid_r getrlimit getrusage jrand48 llseek lseek64 mallinfo mbstowcs memalign mmap msync nanosleep open64 pathconf posix_fadvise posix_memalign prctl setmntent setresgid setresuid srandom strcasecmp strdup strnlen strptime strtoull sync_file_range sysconf usleep utime valloc
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/configure.in b/configure.in
index 68fc806..f2d75cc 100644
--- a/configure.in
+++ b/configure.in
@@ -1053,6 +1053,7 @@ AC_CHECK_FUNCS(m4_flatten([
__secure_getenv
backtrace
blkid_probe_get_topology
+ blkid_probe_step_back
chflags
fallocate
fallocate64
diff --git a/lib/config.h.in b/lib/config.h.in
index 6f88c9c..2735452 100644
--- a/lib/config.h.in
+++ b/lib/config.h.in
@@ -64,6 +64,9 @@
/* Define to 1 if you have the `blkid_probe_get_topology' function. */
#undef HAVE_BLKID_PROBE_GET_TOPOLOGY
+/* Define to 1 if you have the `blkid_probe_step_back' function. */
+#undef HAVE_BLKID_PROBE_STEP_BACK
+
/* Define to 1 if you have the `chflags' function. */
#undef HAVE_CHFLAGS
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index bbf477a..9270b55 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -481,42 +481,42 @@ static void reserve_inodes(ext2_filsys fs)
#define BSD_MAGICDISK (0x57455682UL) /* The disk magic number reversed */
#define BSD_LABEL_OFFSET 64
-static void zap_sector(ext2_filsys fs, int sect, int nsect)
+static int zap_bytes(ext2_filsys fs, unsigned long long offset, int size)
{
char *buf;
int retval;
unsigned int *magic;
- buf = malloc(512*nsect);
+ buf = malloc(size < 512 ? 512 : size);
if (!buf) {
- printf(_("Out of memory erasing sectors %d-%d\n"),
- sect, sect + nsect - 1);
+ com_err(program_name, errno,
+ _("wile allocating memory to erase %d bytes from offset %llu"),
+ size, offset);
exit(1);
}
- if (sect == 0) {
+ if (offset == 0 && size > 64) {
/* Check for a BSD disklabel, and don't erase it if so */
retval = io_channel_read_blk64(fs->io, 0, -512, buf);
if (retval)
- fprintf(stderr,
- _("Warning: could not read block 0: %s\n"),
- error_message(retval));
+ com_err(program_name, retval,
+ _("could not read sector 0"));
else {
magic = (unsigned int *) (buf + BSD_LABEL_OFFSET);
if ((*magic == BSD_DISKMAGIC) ||
(*magic == BSD_MAGICDISK))
- return;
+ return -1;
}
}
- memset(buf, 0, 512*nsect);
- io_channel_set_blksize(fs->io, 512);
- retval = io_channel_write_blk64(fs->io, sect, -512*nsect, buf);
- io_channel_set_blksize(fs->io, fs->blocksize);
+ memset(buf, 0, size);
+ retval = io_channel_write_byte64(fs->io, offset, size, buf);
free(buf);
if (retval)
- fprintf(stderr, _("Warning: could not erase sector %d: %s\n"),
- sect, error_message(retval));
+ com_err(program_name, retval,
+ _("while erasing %d bytes from offset %llu\n"),
+ size, offset);
+ return retval;
}
static void create_journal_dev(ext2_filsys fs)
@@ -2346,6 +2346,140 @@ static int create_quota_inodes(ext2_filsys fs)
return 0;
}
+#ifdef HAVE_BLKID_PROBE_STEP_BACK
+/*
+ * Wipe out all signatures on the device using libblkid
+ */
+static void wipe_signatures(ext2_filsys fs)
+{
+ int value, retval;
+ blkid_probe pr;
+ size_t len = 0;
+ const char *ostr = NULL;
+ const char *name = NULL;
+ long long offset;
+
+ pr = blkid_new_probe_from_filename(fs->device_name);
+
+ blkid_probe_enable_partitions(pr, 1);
+ blkid_probe_enable_superblocks(pr, 1);
+ blkid_probe_set_partitions_flags(pr, BLKID_PARTS_MAGIC);
+ blkid_probe_set_superblocks_flags(pr,
+ BLKID_SUBLKS_MAGIC | BLKID_SUBLKS_TYPE);
+
+ while (1) {
+
+ value = blkid_do_probe(pr);
+ if (value != 0)
+ break;
+
+ if (blkid_probe_lookup_value(pr, "TYPE", &name, NULL) == 0) {
+ blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &ostr,
+ NULL);
+ blkid_probe_lookup_value(pr, "SBMAGIC", NULL, &len);
+
+ } else if (blkid_probe_lookup_value(pr, "PTTYPE",
+ &name, NULL) == 0) {
+ blkid_probe_lookup_value(pr, "PTMAGIC_OFFSET",
+ &ostr, NULL);
+ blkid_probe_lookup_value(pr, "PTMAGIC", NULL, &len);
+ } else
+ continue;
+
+ /* Convert ostr to the real offset */
+ offset = strtoll(ostr, NULL, 10);
+
+ if (verbose)
+ printf(_("Wiping off %s signature from the device: "),
+ name);
+
+ /* Wipe off the signature */
+ retval = zap_bytes(fs, offset, len);
+ if (verbose) {
+ if (retval < 0)
+ printf(_("skipped\n"));
+ else
+ printf(_("done\n"));
+ }
+
+ /*
+ * Retry the last probing to check for backup
+ * superblocks ..etc.
+ * */
+ blkid_probe_step_back(pr);
+ }
+}
+#else
+/*
+ * Wipe out old MD RAID signatures on the device
+ */
+static void wipe_raid(ext2_filsys fs)
+{
+ /* rsv must be a power of two (64kB is MD RAID sb alignment) */
+ blk64_t rsv = 65536 / fs->blocksize;
+ blk64_t blocks = ext2fs_blocks_count(fs->super);
+ blk64_t start;
+ blk64_t ret_blk;
+ int retval = 0;
+
+
+ if (verbose)
+ printf(_("Wiping off linux_raid_member signature from the device: "));
+ /*
+ * Wipe out any old MD RAID (or other) metadata at the end
+ * of the device. This will also verify that the device is
+ * as large as we think. Be careful with very small devices.
+ */
+ start = (blocks & ~(rsv - 1));
+ if (start > rsv)
+ start -= rsv;
+ if (start > 0)
+ retval = ext2fs_zero_blocks2(fs, start, blocks - start,
+ &ret_blk, NULL);
+ if (retval)
+ com_err(program_name, retval,
+ _("while zeroing block %llu at end of filesystem"),
+ ret_blk);
+ else if (verbose)
+ printf(_("done\n"));
+}
+
+/*
+ * Wipe out all btrfs signatures on the device
+ */
+static int wipe_btrfs(ext2_filsys fs)
+{
+ int blocks; /* nr of blocks to zero */
+ blk64_t start; /* location to zero out */
+ int retval = 0; /* accumulate any failures */
+
+ blocks = 1;
+ if (fs->blocksize < 4096)
+ blocks = 4096 / fs->blocksize;
+ /*
+ * Wipe out any old btrfs superblocks, at
+ * 64k, 64M, and 256G.
+ */
+ start = 64ULL * 1024 / fs->blocksize;
+ retval += ext2fs_zero_blocks2(fs, start, blocks, NULL, NULL);
+ start = 64ULL * 1024 * 1024 / fs->blocksize;
+ if (start + blocks <= ext2fs_blocks_count(fs->super))
+ retval += ext2fs_zero_blocks2(fs, start, blocks, NULL, NULL);
+ start = 256ULL * 1024 * 1024 * 1024 / fs->blocksize;
+ if (start + blocks <= ext2fs_blocks_count(fs->super))
+ retval += ext2fs_zero_blocks2(fs, start, blocks, NULL, NULL);
+ if (verbose)
+ printf(_("Wiping off btrfs signature from the device: "));
+ /* free the static zeroing buffer */
+ ext2fs_zero_blocks2(0, 0, 0, 0, 0);
+ if (retval)
+ com_err(program_name, retval,
+ _("while wiping old btrfs super locations"));
+ else if (verbose)
+ printf(_("done\n"));
+}
+#endif /* HAVE_BLKID_PROBE_STEP_BACK */
+
int main (int argc, char *argv[])
{
errcode_t retval = 0;
@@ -2459,8 +2593,10 @@ int main (int argc, char *argv[])
/*
* Wipe out the old on-disk superblock
*/
+ /*
if (!noaction)
zap_sector(fs, 2, 6);
+ */
/*
* Parse or generate a UUID for the filesystem
@@ -2605,33 +2741,33 @@ int main (int argc, char *argv[])
ext2fs_bg_itable_unused_set(fs, i, 0);
}
} else {
- /* rsv must be a power of two (64kB is MD RAID sb alignment) */
- blk64_t rsv = 65536 / fs->blocksize;
- blk64_t blocks = ext2fs_blocks_count(fs->super);
- blk64_t start;
- blk64_t ret_blk;
-
-#ifdef ZAP_BOOTBLOCK
- zap_sector(fs, 0, 2);
+ /* Get rid of the old signatures */
+#ifdef HAVE_BLKID_PROBE_STEP_BACK
+ wipe_signatures(fs);
+#else
+ wipe_btrfs(fs);
+ wipe_raid(fs);
#endif
/*
- * Wipe out any old MD RAID (or other) metadata at the end
- * of the device. This will also verify that the device is
- * as large as we think. Be careful with very small devices.
+ * Overwrite loast block of the file system. There are two
+ * reasons we're doing so:
+ * - we ensure that the device is at least as big as it claims
+ * to be.
+ * - in the case we're creating a file system on the file we
+ * have to set the size of that file properly
*/
- start = (blocks & ~(rsv - 1));
- if (start > rsv)
- start -= rsv;
- if (start > 0)
- retval = ext2fs_zero_blocks2(fs, start, blocks - start,
- &ret_blk, NULL);
-
- if (retval) {
+ retval = ext2fs_zero_blocks2(fs,
+ ext2fs_blocks_count(fs->super) - 1,
+ 1, NULL, NULL);
+ if (retval)
com_err(program_name, retval,
- _("while zeroing block %llu at end of filesystem"),
- ret_blk);
- }
+ "while overwriting last block");
+
+#ifdef ZAP_BOOTBLOCK
+ zap_bytes(fs, 0, 1024);
+#endif
+
write_inode_tables(fs, lazy_itable_init, itable_zeroed);
create_root_dir(fs);
create_lost_and_found(fs);
--
1.7.7.6
--
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