[Cluster-devel] [PATCH 14/15] gfs2: Warn when a journal replay overwrites a rgrp with buffers

[Bob Peterson]

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 <rpete...@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 0ff32e96c9f5..2594cd5bfdd3 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -743,9 +743,27 @@ 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