Re: [PATCH] btrfs-progs: misc-tests: Primary Superblock corruption and recovery using backup Superblock.

["Lakshmipathi.G" <lakshmipathi.g@giis.co.in>]

On Wed, Feb 15, 2017 at 09:36:03AM +0800, Qu Wenruo wrote:
> 
> 
> >+	# Corrupt superblock checksum
> >+        dd if=/dev/zero of=$TEST_DEV seek=$superblock_offset bs=1 \
> >+        count=4  conv=notrunc &> /dev/null
> >+	run_check_stdout $SUDO_HELPER mount $TEST_DEV $TEST_MNT | \
> >+	grep -q 'wrong fs type'
> 
> What about using btrfs check instead of trying to mount it?
> 
> This could emit the need to use $SUDO_HELPER, and could catch super error
> more accurate.
> 
> >+        if [ $? -ne 0 ]; then
> >+		_fail "Failed to corrupt superblock."
> >+        fi
> >+
> >+	# Copy backup superblock to primary
> >+	run_check $TOP/btrfs-select-super -s 1 $TEST_DEV
> >+	run_check $SUDO_HELPER mount $TEST_DEV $TEST_MNT
> Same here.
I started with 'btrfs check' and 'btrfs check --repair' but it seems like
--repair don't fix the corruption. So just moved away from using it.

After you mentioned, now I see 'btrfs check' will be helpful. Will make
these changes. 

Cheers.
Lakshmipathi.G