From a68eb7c7fde165d06e78d2ebd2bdf960b16ffd73 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Wed, 20 Nov 2024 16:24:40 -0800
Subject: [PATCH] xfs_scrub: call GETFSMAP for each rt group in parallel

If realtime groups are enabled, we should take advantage of the sharding
to speed up the spacemap scans.  Do so by issuing per-rtgroup GETFSMAP
calls.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 scrub/spacemap.c | 70 ++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 62 insertions(+), 8 deletions(-)

diff --git a/scrub/spacemap.c b/scrub/spacemap.c
index 4b7fae25..c293ab44 100644
--- a/scrub/spacemap.c
+++ b/scrub/spacemap.c
@@ -127,6 +127,43 @@ scan_ag_rmaps(
 	}
 }
 
+/* Iterate all the reverse mappings of a realtime group. */
+static void
+scan_rtg_rmaps(
+	struct workqueue	*wq,
+	xfs_agnumber_t		rgno,
+	void			*arg)
+{
+	struct scrub_ctx	*ctx = (struct scrub_ctx *)wq->wq_ctx;
+	struct scan_blocks	*sbx = arg;
+	struct fsmap		keys[2] = { };
+	off_t			bperrg = bytes_per_rtgroup(&ctx->mnt.fsgeom);
+	int			ret;
+
+	keys[0].fmr_device = ctx->fsinfo.fs_rtdev;
+	keys[0].fmr_physical = (xfs_rtblock_t)rgno * bperrg;
+	keys[1].fmr_device = ctx->fsinfo.fs_rtdev;
+	keys[1].fmr_physical = ((rgno + 1) * bperrg) - 1;
+	keys[1].fmr_owner = ULLONG_MAX;
+	keys[1].fmr_offset = ULLONG_MAX;
+	keys[1].fmr_flags = UINT_MAX;
+
+	if (sbx->aborted)
+		return;
+
+	ret = scrub_iterate_fsmap(ctx, keys, sbx->fn, sbx->arg);
+	if (ret) {
+		char		descr[DESCR_BUFSZ];
+
+		snprintf(descr, DESCR_BUFSZ, _("dev %d:%d rtgroup %u fsmap"),
+					major(ctx->fsinfo.fs_datadev),
+					minor(ctx->fsinfo.fs_datadev),
+					rgno);
+		str_liberror(ctx, ret, descr);
+		sbx->aborted = true;
+	}
+}
+
 /* Iterate all the reverse mappings of a standalone device. */
 static void
 scan_dev_rmaps(
@@ -206,14 +243,6 @@ scrub_scan_all_spacemaps(
 		str_liberror(ctx, ret, _("creating fsmap workqueue"));
 		return ret;
 	}
-	if (ctx->fsinfo.fs_rt) {
-		ret = -workqueue_add(&wq, scan_rt_rmaps, 0, &sbx);
-		if (ret) {
-			sbx.aborted = true;
-			str_liberror(ctx, ret, _("queueing rtdev fsmap work"));
-			goto out;
-		}
-	}
 	if (ctx->fsinfo.fs_log) {
 		ret = -workqueue_add(&wq, scan_log_rmaps, 0, &sbx);
 		if (ret) {
@@ -230,6 +259,31 @@ scrub_scan_all_spacemaps(
 			break;
 		}
 	}
+	if (ctx->fsinfo.fs_rt) {
+		for (agno = 0; agno < ctx->mnt.fsgeom.rgcount; agno++) {
+			ret = -workqueue_add(&wq, scan_rtg_rmaps, agno, &sbx);
+			if (ret) {
+				sbx.aborted = true;
+				str_liberror(ctx, ret,
+						_("queueing rtgroup fsmap work"));
+				break;
+			}
+		}
+
+		/*
+		 * If the fs doesn't have any realtime groups, scan the entire
+		 * volume all at once, since the above loop did nothing.
+		 */
+		if (ctx->mnt.fsgeom.rgcount == 0) {
+			ret = -workqueue_add(&wq, scan_rt_rmaps, 0, &sbx);
+			if (ret) {
+				sbx.aborted = true;
+				str_liberror(ctx, ret,
+						_("queueing rtdev fsmap work"));
+				goto out;
+			}
+		}
+	}
 out:
 	ret = -workqueue_terminate(&wq);
 	if (ret) {
-- 
2.47.3