btrfs: check qgroup doesn't crash when beyond limit
There is a bug that, when btrfs is beyond qgroup limit, touching a file
could crash btrfs.
Such beyond limit situation needs to be intentionally created, e.g.
writing 1GiB file, then limit the subvolume to 512 MiB.
As current qgroup works pretty well at preventing us from reaching the
limit.
This makes existing qgroup test cases unable to detect it.
The regression is introduced by commit c53e9653605d ("btrfs: qgroup:
try to flush qgroup space when we get -EDQUOT"), and the fix is
commit 6f23277a49e6 ("btrfs: qgroup: don't commit transaction when
we already hold the handle")
Link: https://bugzilla.suse.com/show_bug.cgi?id=1178634
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
3 files changed
