[PATCH 134/145] xfs_repair: check for mergeable refcount records

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

Make sure there aren't adjacent refcount records that could be merged;
this is a sign that the refcount tree algorithms aren't working
correctly.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 repair/scan.c |   25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)


diff --git a/repair/scan.c b/repair/scan.c
index 1c2afb6..d2e588a 100644
--- a/repair/scan.c
+++ b/repair/scan.c
@@ -1195,6 +1195,11 @@ out:
                rmap_avoid_check();
 }
 
+struct refc_priv {
+       struct xfs_refcount_irec        last_rec;
+};
+
+
 static void
 scan_refcbt(
        struct xfs_btree_block  *block,
@@ -1214,6 +1219,7 @@ scan_refcbt(
        int                     numrecs;
        int                     state;
        xfs_agblock_t           lastblock = 0;
+       struct refc_priv        *refc_priv = priv;
 
        if (magic != XFS_REFC_CRC_MAGIC) {
                name = "(unknown)";
@@ -1331,6 +1337,20 @@ _("extent (%u/%u) len %u claimed, state is %d\n"),
                                lastblock = b;
                        }
 
+                       /* Is this record mergeable with the last one? */
+                       if (refc_priv->last_rec.rc_startblock +
+                           refc_priv->last_rec.rc_blockcount == b &&
+                           refc_priv->last_rec.rc_refcount == nr) {
+                               do_warn(
+       _("record %d in block (%u/%u) of %s tree should be merged with previous 
record\n"),
+                                       i, agno, bno, name);
+                               refc_priv->last_rec.rc_blockcount += len;
+                       } else {
+                               refc_priv->last_rec.rc_startblock = b;
+                               refc_priv->last_rec.rc_blockcount = len;
+                               refc_priv->last_rec.rc_refcount = nr;
+                       }
+
                        /* XXX: probably want to mark the reflinked areas? */
                }
                goto out;
@@ -2169,10 +2189,13 @@ validate_agf(
        if (xfs_sb_version_hasreflink(&mp->m_sb)) {
                bno = be32_to_cpu(agf->agf_refcount_root);
                if (bno != 0 && verify_agbno(mp, agno, bno)) {
+                       struct refc_priv        priv;
+
+                       memset(&priv, 0, sizeof(priv));
                        scan_sbtree(bno,
                                    be32_to_cpu(agf->agf_refcount_level),
                                    agno, 0, scan_refcbt, 1, XFS_REFC_CRC_MAGIC,
-                                   agcnts, &xfs_refcountbt_buf_ops);
+                                   &priv, &xfs_refcountbt_buf_ops);
                } else  {
                        do_warn(_("bad agbno %u for refcntbt root, agno %d\n"),
                                bno, agno);