xfs: change bmap scrubber to store the previous mapping

Convert the inode data/attr/cow fork scrubber to remember the entire
previous mapping, not just the next expected offset.  No behavior
changes here, but this will enable some better checking in subsequent
patches.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
index e485a54..7b4d0e2 100644 (file)
--- a/fs/xfs/scrub/bmap.c
+++ b/fs/xfs/scrub/bmap.c
@@ -96,11 +96,23 @@ out:
 
 struct xchk_bmap_info {
        struct xfs_scrub        *sc;
+
+       /* Incore extent tree cursor */
        struct xfs_iext_cursor  icur;
-       xfs_fileoff_t           lastoff;
+
+       /* Previous fork mapping that we examined */
+       struct xfs_bmbt_irec    prev_rec;
+
+       /* Is this a realtime fork? */
        bool                    is_rt;
+
+       /* May mappings point to shared space? */
        bool                    is_shared;
+
+       /* Was the incore extent tree loaded? */
        bool                    was_loaded;
+
+       /* Which inode fork are we checking? */
        int                     whichfork;
 };
 
@@ -405,7 +417,8 @@ xchk_bmap_iextent(
         * Check for out-of-order extents.  This record could have come
         * from the incore list, for which there is no ordering check.
         */
-       if (irec->br_startoff < info->lastoff)
+       if (irec->br_startoff < info->prev_rec.br_startoff +
+                               info->prev_rec.br_blockcount)
                xchk_fblock_set_corrupt(info->sc, info->whichfork,
                                irec->br_startoff);
 
@@ -712,7 +725,8 @@ xchk_bmap_iextent_delalloc(
         * Check for out-of-order extents.  This record could have come
         * from the incore list, for which there is no ordering check.
         */
-       if (irec->br_startoff < info->lastoff)
+       if (irec->br_startoff < info->prev_rec.br_startoff +
+                               info->prev_rec.br_blockcount)
                xchk_fblock_set_corrupt(info->sc, info->whichfork,
                                irec->br_startoff);
 
@@ -806,7 +820,6 @@ xchk_bmap(
                goto out;
 
        /* Scrub extent records. */
-       info.lastoff = 0;
        ifp = xfs_ifork_ptr(ip, whichfork);
        for_each_xfs_iext(ifp, &info.icur, &irec) {
                if (xchk_should_terminate(sc, &error) ||
@@ -823,7 +836,7 @@ xchk_bmap(
                        xchk_bmap_iextent_delalloc(ip, &info, &irec);
                else
                        xchk_bmap_iextent(ip, &info, &irec);
-               info.lastoff = irec.br_startoff + irec.br_blockcount;
+               memcpy(&info.prev_rec, &irec, sizeof(struct xfs_bmbt_irec));
        }
 
        error = xchk_bmap_check_rmaps(sc, whichfork);