xfs: fix delalloc quota accounting on failure

xfstest 270 was causing quota reservations way beyond what was sane
(ten to hundreds of TB) for a 4GB filesystem. There's a sign problem
in the error handling path of xfs_bmapi_reserve_delalloc() because
xfs_trans_unreserve_quota_nblks() simple negates the value passed -
which doesn't work for an unsigned variable. This causes
reservations of close to 2^32 block instead of removing a
reservation of a handful of blocks.

Fix the same problem in the other xfs_trans_unreserve_quota_nblks()
callers where unsigned integer variables are used, too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_bmap.c

@@ -4526,7 +4526,7 @@ out_unreserve_blocks:
 		xfs_icsb_modify_counters(mp, XFS_SBS_FDBLOCKS, alen, 0);
 out_unreserve_quota:
 	if (XFS_IS_QUOTA_ON(mp))
-		xfs_trans_unreserve_quota_nblks(NULL, ip, alen, 0, rt ?
+		xfs_trans_unreserve_quota_nblks(NULL, ip, (long)alen, 0, rt ?
 				XFS_QMOPT_RES_RTBLKS : XFS_QMOPT_RES_REGBLKS);
 	return error;
 }

fs/xfs/xfs_iomap.c

@@ -246,7 +246,7 @@ out_unlock:
 
 out_bmap_cancel:
 	xfs_bmap_cancel(&free_list);
-	xfs_trans_unreserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
+	xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag);
 out_trans_cancel:
 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
 	goto out_unlock;

fs/xfs/xfs_vnodeops.c

@@ -1916,7 +1916,7 @@ xfs_alloc_file_space(
 
 error0:	/* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
 	xfs_bmap_cancel(&free_list);
-	xfs_trans_unreserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
+	xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag);
 
 error1:	/* Just cancel transaction */
 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);