xfs: enable realtime quota again

Enable quotas for the realtime device.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Author: Darrick J. Wong

fs/xfs/xfs_qm.c

@@ -1663,10 +1663,11 @@ xfs_qm_mount_quotas(
 	uint			sbf;
 
 	/*
-	 * If quotas on realtime volumes is not supported, we disable
-	 * quotas immediately.
+	 * If quotas on realtime volumes is not supported, disable quotas
+	 * immediately.  We only support rtquota if rtgroups are enabled to
+	 * avoid problems with older kernels.
 	 */
-	if (mp->m_sb.sb_rextents) {
+	if (mp->m_sb.sb_rextents && !xfs_has_rtgroups(mp)) {
 		xfs_notice(mp, "Cannot turn on quotas for realtime filesystem");
 		mp->m_qflags = 0;
 		goto write_changes;

fs/xfs/xfs_rtalloc.c

@@ -1265,7 +1265,9 @@ xfs_growfs_rt(
 
 	/* Unsupported realtime features. */
 	error = -EOPNOTSUPP;
-	if (xfs_has_rmapbt(mp) || xfs_has_reflink(mp) || xfs_has_quota(mp))
+	if (xfs_has_quota(mp) && !xfs_has_rtgroups(mp))
+		goto out_unlock;
+	if (xfs_has_rmapbt(mp) || xfs_has_reflink(mp))
 		goto out_unlock;
 
 	error = xfs_sb_validate_fsb_count(&mp->m_sb, in->newblocks);