Here is a test case which says it all..
mkfs.xfs -f $DEV
mkfs.btrfs -f $DEV
mount $DEV $MNT
mount: /dev/vdiskc: more filesystems detected. This should not happen,
use -t <type> to explicitly specify the filesystem type or
use wipefs(8) to clean up the device.
mount: you must specify the filesystem type
with this patch btrfs_prepare_device() also wipes old FS if any,
btrfs_prepare_device() is called after we have verified that
user has provided -f option.
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
utils.c | 31 +++++++++++++++++++++++++++++++
1 files changed, 31 insertions(+), 0 deletions(-)
diff --git a/utils.c b/utils.c
index 0064587..8b0c751 100644
--- a/utils.c
+++ b/utils.c
@@ -678,6 +678,35 @@ int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
return 0;
}
+static void wipe_existing_fs(int fd)
+{
+ blkid_probe pr = NULL;
+
+ pr = blkid_new_probe();
+ if (!pr)
+ return;
+
+ if (blkid_probe_set_device(pr, fd, 0, 0))
+ goto out;
+
+ blkid_probe_enable_superblocks(pr, 1);
+ blkid_probe_set_superblocks_flags(pr,
+ BLKID_SUBLKS_MAGIC |
+ BLKID_SUBLKS_TYPE |
+ BLKID_SUBLKS_USAGE |
+ BLKID_SUBLKS_LABEL |
+ BLKID_SUBLKS_UUID);
+
+ blkid_probe_enable_partitions(pr, 1);
+
+ while (blkid_do_probe(pr) == 0)
+ blkid_do_wipe(pr, 0);
+
+ fsync(fd);
+out:
+ blkid_free_probe(pr);
+}
+
int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
u64 max_block_count, int *mixed, int discard)
{
@@ -729,6 +758,8 @@ int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
return 1;
}
+ wipe_existing_fs(fd);
+
*block_count_ret = block_count;
return 0;
}
--
1.7.1
--
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