[PATCH 26/29] xfs_repair: check existing realtime rmapbt entries against observed rmaps

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

Once we've finished collecting reverse mapping observations from the
metadata scan, check those observations against the realtime rmap btree
(particularly if we're in -n mode) to detect rtrmapbt problems.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 repair/rmap.c |   48 +++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 39 insertions(+), 9 deletions(-)


diff --git a/repair/rmap.c b/repair/rmap.c
index 37da251..d6a75d7 100644
--- a/repair/rmap.c
+++ b/repair/rmap.c
@@ -1008,6 +1008,7 @@ rmaps_verify_btree(
        struct xfs_rmap_irec    *rm_rec;
        struct xfs_rmap_irec    tmp;
        struct xfs_perag        *pag;           /* per allocation group data */
+       struct xfs_inode        *ip = NULL;
 
        if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
                return 0;
@@ -1016,22 +1017,47 @@ rmaps_verify_btree(
                        do_warn(_("would rebuild corrupt rmap btrees.\n"));
                return 0;
        }
+       if (agno == NULLAGNUMBER && mp->m_sb.sb_rblocks == 0) {
+               if (rmap_record_count(mp, NULLAGNUMBER) != 0) {
+                       do_error(_("realtime extents but no rtdev?\n"));
+                       return -EFSCORRUPTED;
+               }
+               return 0;
+       }
 
-       /* Create cursors to refcount structures */
+       /* Create cursors to rmap structures */
        error = rmap_init_cursor(agno, &rm_cur);
        if (error)
                return error;
 
-       error = -libxfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
-       if (error)
-               goto err;
+       if (agno == NULLAGNUMBER) {
+               if (mp->m_sb.sb_rrmapino == 0 ||
+                   mp->m_sb.sb_rrmapino == NULLFSINO) {
+                       do_warn(
+_("garbage in sb_rrmapino, not checking realtime rmaps\n"));
+                       goto err;
+               }
 
-       /* Leave the per-ag data "uninitialized" since we rewrite it later */
-       pag = libxfs_perag_get(mp, agno);
-       pag->pagf_init = 0;
-       libxfs_perag_put(pag);
+               error = -libxfs_iget(mp, NULL, mp->m_sb.sb_rrmapino, 0, &ip, 0);
+               if (error) {
+                       do_warn(_("%d - couldn't iget rtrmap inode.\n"),
+                                error);
+                       goto err;
+               }
+               mp->m_rrmapip = ip;
+               bt_cur = libxfs_rtrmapbt_init_cursor(mp, NULL, mp->m_rrmapip);
+       } else {
+               error = -libxfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+               if (error)
+                       goto err;
+
+               /* Leave the per-ag data "uninitialized" since we rewrite it 
later */
+               pag = libxfs_perag_get(mp, agno);
+               pag->pagf_init = 0;
+               libxfs_perag_put(pag);
 
-       bt_cur = libxfs_rmapbt_init_cursor(mp, NULL, agbp, agno);
+               bt_cur = libxfs_rmapbt_init_cursor(mp, NULL, agbp, agno);
+       }
        if (!bt_cur) {
                error = -ENOMEM;
                goto err;
@@ -1107,6 +1133,10 @@ err:
                libxfs_btree_del_cursor(bt_cur, XFS_BTREE_NOERROR);
        if (agbp)
                libxfs_putbuf(agbp);
+       if (ip) {
+               IRELE(mp->m_rrmapip);
+               mp->m_rrmapip = NULL;
+       }
        free_slab_cursor(&rm_cur);
        return 0;
 }