Btrfs: fix small race with delalloc flushing waitqueue's
Btrfs: fix small race with delalloc flushing waitqueue's

Everytime we start a new flushing thread, we init the waitqueue if there isn't a
flushing thread running.  The problem with this is we check
space_info->flushing, which we clear right before doing a wake_up on the
flushing waitqueue, which causes problems if we init the waitqueue in the middle
of clearing the flushing flagh and calling wake_up.  This is hard to hit, but
the code is wrong anyway, so init the flushing/allocating waitqueue when
creating the space info and let it be.  I haven't seen the panic since I've been
using this patch.  Thanks,

Signed-off-by: Josef Bacik <78b342861d821967b29f951b7366f5a0267e0c38@redhat.com>
Signed-off-by: Chris Mason <a169954b4cb1a46cee25f659d3bddfebe02b5fba@oracle.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas