xfs: check for null dquot in xfs_quota_calc_throttle()

Coverity spotted this.

Granted, we *just* checked xfs_inod_dquot() in the caller (by
calling xfs_quota_need_throttle). However, this is the only place we
don't check the return value but the check is cheap and future-proof
so add it.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index e9c47b6f5e5a..afcf3c926565 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -404,8 +404,8 @@ xfs_quota_calc_throttle(
         int shift = 0;
         struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
 
-        /* over hi wmark, squash the prealloc completely */
-        if (dq->q_res_bcount >= dq->q_prealloc_hi_wmark) {
+        /* no dq, or over hi wmark, squash the prealloc completely */
+        if (!dq || dq->q_res_bcount >= dq->q_prealloc_hi_wmark) {
                 *qblocks = 0;
                 *qfreesp = 0;
                 return;