libxfs: don't send null bp to xfs_trans_brelse()

In this case, if bp is null, error is set, and we send
bp to xfs_trans_brelse, which will try to dereference it.

Test whether we actualy have a buffer before we try to
free it.

Same fix as was sent for kernelspace.

Coverity spotted this.

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

diff --git a/libxfs/xfs_da_btree.c b/libxfs/xfs_da_btree.c
index b70454ee25caf16c563ecd3bac8592d02b7a8dbc..b731b5451f055c17ca8842cff9ba518444759de3 100644 (file)
--- a/libxfs/xfs_da_btree.c
+++ b/libxfs/xfs_da_btree.c
@@ -2582,7 +2582,8 @@ xfs_da_get_buf(
                                    mapp, nmap, 0);
        error = bp ? bp->b_error : XFS_ERROR(EIO);
        if (error) {
-               xfs_trans_brelse(trans, bp);
+               if (bp)
+                       xfs_trans_brelse(trans, bp);
                goto out_free;
        }