On Fri, Apr 9, 2021 at 12:32 PM Wang Yugui <[email protected]> wrote: > > Hi, > > > btrfs_wipe_existing_sb() misses calling blkid_do_fullprobe() to do > > the real probe. After calling blkid_new_probe() & > > blkid_probe_set_device() to setup blkid_probe context, it directly > > calls blkid_probe_lookup_value(). This results in > > blkid_probe_lookup_value returning -1, because pr->values is empty. > > > > Signed-off-by: Fox Chen <[email protected]> > > --- > > common/device-utils.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/common/device-utils.c b/common/device-utils.c > > index c860b946..f8e2e776 100644 > > --- a/common/device-utils.c > > +++ b/common/device-utils.c > > @@ -114,7 +114,7 @@ static int btrfs_wipe_existing_sb(int fd) > > if (!pr) > > return -1; > > > > - if (blkid_probe_set_device(pr, fd, 0, 0)) { > > + if (blkid_probe_set_device(pr, fd, 0, 0) || blkid_do_fullprobe(pr)) { > > ret = -1; > > goto out; > > } > > -- > > 2.31.0 > > > With this patch, 'mkfs.btrfs -f /dev/nvme0n1 /dev/sdb' output some > error when /dev/nvme0n1 have 2 partitions. > ERROR: cannot wipe superblocks on /dev/nvme0n1
I am not sure this error is caused by my improper fix, or bugs lie somewhere else on mkfs.btrfs path. But without this patch, I think, btrfs_wipe_existing_sb will not do what is supposed to do -- wiping out existing superblocks. Instead, it does nothing and always returns 1. Since it has no effect and nobody complaints about it, that brings a question, do we really need to call it in btrfs_prepare_device? > # blkid > /dev/nvme0n1: PTUUID="93a54ce8-04b2-470b-8c05-31bfcef02f28" PTTYPE="gpt" > /dev/sda1: LABEL="OS_USB" UUID="2b7f4cb9-3dac-443f-8c96-a907b9276942" > BLOCK_SIZE="512" TYPE="xfs" PARTUUID="ee58e9d3-01" > /dev/nvme0n1p1: UUID="1d94dc2b-abd1-47df-bf39-ab31cf579d29" > UUID_SUB="577542b7-91f5-48d4-a54c-98cbd4525c00" BLOCK_SIZE="4096" > TYPE="btrfs" PARTLABEL="primary" > PARTUUID="efed009f-8ae6-4567-9cd3-80a57cdcf225" > /dev/nvme0n1p2: PARTLABEL="primary" > PARTUUID="fcab66cd-daad-457f-a53c-110592d8941f" > ... > > > Without this patch, 'mkfs.btrfs -f /dev/nvme0n1 /dev/sdb' have some > issue too when /dev/nvme0n1 and /dev/sdb have some partitions. > > some blkid of partition is still left in the output of blkid. > 'blockdev --rereadpt' will let them disappear. > > Best Regards > Wang Yugui ([email protected]) > 2021/04/09 > > thanks, fox
