xfs: split xchk_bmap_xref_rmap into two functions

There's more special-cased functionality than not in this function.
Split it into two so that each can be far more cohesive.

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 4bda1b0..912b67d 100644 (file)
--- a/fs/xfs/scrub/bmap.c
+++ b/fs/xfs/scrub/bmap.c
@@ -165,7 +165,7 @@ xchk_bmap_get_rmap(
        return has_rmap;
 }
 
-/* Make sure that we have rmapbt records for this extent. */
+/* Make sure that we have rmapbt records for this data/attr fork extent. */
 STATIC void
 xchk_bmap_xref_rmap(
        struct xchk_bmap_info   *info,
@@ -174,41 +174,39 @@ xchk_bmap_xref_rmap(
 {
        struct xfs_rmap_irec    rmap;
        unsigned long long      rmap_end;
-       uint64_t                owner;
+       uint64_t                owner = info->sc->ip->i_ino;
 
        if (!info->sc->sa.rmap_cur || xchk_skip_xref(info->sc->sm))
                return;
 
-       if (info->whichfork == XFS_COW_FORK)
-               owner = XFS_RMAP_OWN_COW;
-       else
-               owner = info->sc->ip->i_ino;
-
        /* Find the rmap record for this irec. */
        if (!xchk_bmap_get_rmap(info, irec, agbno, owner, &rmap))
                return;
 
-       /* Check the rmap. */
+       /*
+        * The rmap must be an exact match for this incore file mapping record,
+        * which may have arisen from multiple ondisk records.
+        */
+       if (rmap.rm_startblock != agbno)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
+
        rmap_end = (unsigned long long)rmap.rm_startblock + rmap.rm_blockcount;
-       if (rmap.rm_startblock > agbno ||
-           agbno + irec->br_blockcount > rmap_end)
+       if (rmap_end != agbno + irec->br_blockcount)
                xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
                                irec->br_startoff);
 
-       /*
-        * Check the logical offsets if applicable.  CoW staging extents
-        * don't track logical offsets since the mappings only exist in
-        * memory.
-        */
-       if (info->whichfork != XFS_COW_FORK) {
-               rmap_end = (unsigned long long)rmap.rm_offset +
-                               rmap.rm_blockcount;
-               if (rmap.rm_offset > irec->br_startoff ||
-                   irec->br_startoff + irec->br_blockcount > rmap_end)
-                       xchk_fblock_xref_set_corrupt(info->sc,
-                                       info->whichfork, irec->br_startoff);
-       }
+       /* Check the logical offsets. */
+       if (rmap.rm_offset != irec->br_startoff)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
+
+       rmap_end = (unsigned long long)rmap.rm_offset + rmap.rm_blockcount;
+       if (rmap_end != irec->br_startoff + irec->br_blockcount)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
 
+       /* Check the owner */
        if (rmap.rm_owner != owner)
                xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
                                irec->br_startoff);
@@ -220,8 +218,7 @@ xchk_bmap_xref_rmap(
         * records because the blocks are owned (on-disk) by the refcountbt,
         * which doesn't track unwritten state.
         */
-       if (owner != XFS_RMAP_OWN_COW &&
-           !!(irec->br_state == XFS_EXT_UNWRITTEN) !=
+       if (!!(irec->br_state == XFS_EXT_UNWRITTEN) !=
            !!(rmap.rm_flags & XFS_RMAP_UNWRITTEN))
                xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
                                irec->br_startoff);
@@ -233,23 +230,60 @@ xchk_bmap_xref_rmap(
        if (rmap.rm_flags & XFS_RMAP_BMBT_BLOCK)
                xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
                                irec->br_startoff);
+}
+
+/* Make sure that we have rmapbt records for this COW fork extent. */
+STATIC void
+xchk_bmap_xref_rmap_cow(
+       struct xchk_bmap_info   *info,
+       struct xfs_bmbt_irec    *irec,
+       xfs_agblock_t           agbno)
+{
+       struct xfs_rmap_irec    rmap;
+       unsigned long long      rmap_end;
+       uint64_t                owner = XFS_RMAP_OWN_COW;
+
+       if (!info->sc->sa.rmap_cur || xchk_skip_xref(info->sc->sm))
+               return;
+
+       /* Find the rmap record for this irec. */
+       if (!xchk_bmap_get_rmap(info, irec, agbno, owner, &rmap))
+               return;
 
        /*
-        * The rmap must correspond exactly with this bmbt record.  Skip this
-        * for CoW fork extents because the refcount btree (and not the inode)
-        * is the ondisk owner for those extents.
+        * CoW staging extents are owned by the refcount btree, so the rmap
+        * can start before and end after the physical space allocated to this
+        * mapping.  There are no offsets to check.
         */
-       if (info->whichfork != XFS_COW_FORK) {
-               if (rmap.rm_startblock != agbno)
-                       xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
-                                       irec->br_startoff);
-
-               rmap_end = (unsigned long long)rmap.rm_startblock +
-                                              rmap.rm_blockcount;
-               if (rmap_end != agbno + irec->br_blockcount)
-                       xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
-                                       irec->br_startoff);
-       }
+       if (rmap.rm_startblock > agbno)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
+
+       rmap_end = (unsigned long long)rmap.rm_startblock + rmap.rm_blockcount;
+       if (rmap_end < agbno + irec->br_blockcount)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
+
+       /* Check the owner */
+       if (rmap.rm_owner != owner)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
+
+       /*
+        * No flags allowed.  Note that the (in-memory) CoW fork distinguishes
+        * between unwritten and written extents, but we don't track that in
+        * the rmap records because the blocks are owned (on-disk) by the
+        * refcountbt, which doesn't track unwritten state.
+        */
+       if (rmap.rm_flags & XFS_RMAP_ATTR_FORK)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
+       if (rmap.rm_flags & XFS_RMAP_BMBT_BLOCK)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
+       if (rmap.rm_flags & XFS_RMAP_UNWRITTEN)
+               xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
+                               irec->br_startoff);
 }
 
 /* Cross-reference a single rtdev extent record. */
@@ -288,9 +322,9 @@ xchk_bmap_iextent_xref(
 
        xchk_xref_is_used_space(info->sc, agbno, len);
        xchk_xref_is_not_inode_chunk(info->sc, agbno, len);
-       xchk_bmap_xref_rmap(info, irec, agbno);
        switch (info->whichfork) {
        case XFS_DATA_FORK:
+               xchk_bmap_xref_rmap(info, irec, agbno);
                if (!xfs_is_reflink_inode(info->sc->ip)) {
                        xfs_rmap_ino_owner(&oinfo, info->sc->ip->i_ino,
                                        info->whichfork, irec->br_startoff);
@@ -303,6 +337,7 @@ xchk_bmap_iextent_xref(
                                irec->br_blockcount);
                break;
        case XFS_ATTR_FORK:
+               xchk_bmap_xref_rmap(info, irec, agbno);
                xfs_rmap_ino_owner(&oinfo, info->sc->ip->i_ino,
                                info->whichfork, irec->br_startoff);
                xchk_xref_is_only_owned_by(info->sc, agbno, irec->br_blockcount,
@@ -313,6 +348,7 @@ xchk_bmap_iextent_xref(
                                irec->br_blockcount);
                break;
        case XFS_COW_FORK:
+               xchk_bmap_xref_rmap_cow(info, irec, agbno);
                xchk_xref_is_only_owned_by(info->sc, agbno, irec->br_blockcount,
                                &XFS_RMAP_OINFO_COW);
                xchk_xref_is_cow_staging(info->sc, agbno,