[Cluster-devel] [PATCH 14/19] gfs2: Warn when a journal replay overwrites a rgrp with buffers

[Bob Peterson <rpeterso@redhat.com>]

This patch adds some instrumentation in gfs2's journal replay that
indicates when we're about to overwrite a rgrp for which we already
have a valid buffer_head.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
 fs/gfs2/lops.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 627738cfe6bb..11d2fdeed8ac 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -567,9 +567,27 @@ static int buf_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
 
 		if (gfs2_meta_check(sdp, bh_ip))
 			error = -EIO;
-		else
+		else {
+			struct gfs2_meta_header *mh =
+				(struct gfs2_meta_header *)bh_ip->b_data;
+
+			if (mh->mh_type == cpu_to_be32(GFS2_METATYPE_RG)) {
+				struct gfs2_rgrpd *rgd;
+
+				rgd = gfs2_blk2rgrpd(sdp, blkno, false);
+				if (rgd && rgd->rd_addr == blkno &&
+				    rgd->rd_bits && rgd->rd_bits->bi_bh) {
+					fs_info(sdp, "Replaying 0x%llx but we "
+						"already have a bh!\n",
+						(unsigned long long)blkno);
+					fs_info(sdp, "busy:%d, pinned:%d\n",
+						buffer_busy(rgd->rd_bits->bi_bh) ? 1 : 0,
+						buffer_pinned(rgd->rd_bits->bi_bh));
+					gfs2_dump_glock(NULL, rgd->rd_gl);
+				}
+			}
 			mark_buffer_dirty(bh_ip);
-
+		}
 		brelse(bh_log);
 		brelse(bh_ip);
 
-- 
2.20.1