quota: report warning limits for realtime space quotas

Report the number of warnings that a user will get for exceeding the
soft limit of a realtime volume.  This plugs a gap needed before we
can land a realtime quota implementation for XFS in the next cycle.

Link: https://lore.kernel.org/r/20210318041736.GB22094@magnoliaSigned-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/quota/quota.c

@@ -472,6 +472,7 @@ static int quota_getstatev(struct super_block *sb, int type,
 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
+	fqs->qs_rtbwarnlimit = state.s_state[type].rt_spc_warnlimit;
 
 	/* Inodes may be allocated even if inactive; copy out if present */
 	if (state.s_state[USRQUOTA].ino) {

include/uapi/linux/dqblk_xfs.h

@@ -219,7 +219,10 @@ struct fs_quota_statv {
 	__s32			qs_rtbtimelimit;/* limit for rt blks timer */
 	__u16			qs_bwarnlimit;	/* limit for num warnings */
 	__u16			qs_iwarnlimit;	/* limit for num warnings */
-	__u64			qs_pad2[8];	/* for future proofing */
+	__u16			qs_rtbwarnlimit;/* limit for rt blks warnings */
+	__u16			qs_pad3;
+	__u32			qs_pad4;
+	__u64			qs_pad2[7];	/* for future proofing */
 };
 
 #endif	/* _LINUX_DQBLK_XFS_H */