xfs_repair: improve rtbitmap discrepancy reporting

Improve the reporting of discrepancies in the realtime bitmap and
summary files by creating a separate helper function that will pinpoint
the exact (word) locations of mismatches.  This will help developers to
diagnose problems with the rtgroups feature and users to figure out
exactly what's bad in a filesystem.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/repair/rt.c b/repair/rt.c
index 29ac5a049bf3dbdfa23ed5202da1abaac95c0400..931353cc0d058636d53d10a07617932f4fb9a873 100644 (file)
--- a/repair/rt.c
+++ b/repair/rt.c
@@ -131,6 +131,44 @@ _("couldn't allocate memory for incore realtime summary info.\n"));
        }
 }
 
+static void
+check_rtwords(
+       struct xfs_mount        *mp,
+       const char              *filename,
+       unsigned long long      bno,
+       void                    *ondisk,
+       void                    *incore)
+{
+       unsigned int            wordcnt = mp->m_blockwsize;
+       union xfs_rtword_raw    *o = ondisk, *i = incore;
+       int                     badstart = -1;
+       unsigned int            j;
+
+       if (memcmp(ondisk, incore, wordcnt << XFS_WORDLOG) == 0)
+               return;
+
+       for (j = 0; j < wordcnt; j++, o++, i++) {
+               if (o->old == i->old) {
+                       /* Report a range of inconsistency that just ended. */
+                       if (badstart >= 0)
+                               do_warn(
+ _("discrepancy in %s at dblock 0x%llx words 0x%x-0x%x/0x%x\n"),
+                                       filename, bno, badstart, j - 1, wordcnt);
+                       badstart = -1;
+                       continue;
+               }
+
+               if (badstart == -1)
+                       badstart = j;
+       }
+
+       if (badstart >= 0)
+               do_warn(
+ _("discrepancy in %s at dblock 0x%llx words 0x%x-0x%x/0x%x\n"),
+                                       filename, bno, badstart, wordcnt,
+                                       wordcnt);
+}
+
 static void
 check_rtfile_contents(
        struct xfs_mount        *mp,
@@ -187,9 +225,7 @@ check_rtfile_contents(
                        break;
                }
 
-               if (memcmp(bp->b_addr, buf, mp->m_blockwsize << XFS_WORDLOG))
-                       do_warn(_("discrepancy in %s at dblock 0x%llx\n"),
-                                       filename, (unsigned long long)bno);
+               check_rtwords(mp, filename, bno, bp->b_addr, buf);
 
                buf += XFS_FSB_TO_B(mp, map.br_blockcount);
                bno += map.br_blockcount;