xfs: don't assume a left rmap when allocating a new rmap

Source kernel commit: fa248de98a6beb9ceaec5059041d65f87ac438b4

The original rmap code assumed that there would always be at least one
rmap in the rmapbt (the AG sb/agf/agi) and so errored out if it didn't
find one.  This assumption isn't true for the rmapbt repair function
(and it won't be true for realtime rmap either), so remove the check and
just deal with the situation.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_rmap.c b/libxfs/xfs_rmap.c
index 3cbba4ba79539038eaf89af53950215aea966dbc..8e5f86d57ce3817d55f37ecca9fa6193177d64f7 100644 (file)
--- a/libxfs/xfs_rmap.c
+++ b/libxfs/xfs_rmap.c
@@ -751,19 +751,19 @@ xfs_rmap_map(
                        &have_lt);
        if (error)
                goto out_error;
-       XFS_WANT_CORRUPTED_GOTO(mp, have_lt == 1, out_error);
-
-       error = xfs_rmap_get_rec(cur, &ltrec, &have_lt);
-       if (error)
-               goto out_error;
-       XFS_WANT_CORRUPTED_GOTO(mp, have_lt == 1, out_error);
-       trace_xfs_rmap_lookup_le_range_result(cur->bc_mp,
-                       cur->bc_private.a.agno, ltrec.rm_startblock,
-                       ltrec.rm_blockcount, ltrec.rm_owner,
-                       ltrec.rm_offset, ltrec.rm_flags);
+       if (have_lt) {
+               error = xfs_rmap_get_rec(cur, &ltrec, &have_lt);
+               if (error)
+                       goto out_error;
+               XFS_WANT_CORRUPTED_GOTO(mp, have_lt == 1, out_error);
+               trace_xfs_rmap_lookup_le_range_result(cur->bc_mp,
+                               cur->bc_private.a.agno, ltrec.rm_startblock,
+                               ltrec.rm_blockcount, ltrec.rm_owner,
+                               ltrec.rm_offset, ltrec.rm_flags);
 
-       if (!xfs_rmap_is_mergeable(&ltrec, owner, flags))
-               have_lt = 0;
+               if (!xfs_rmap_is_mergeable(&ltrec, owner, flags))
+                       have_lt = 0;
+       }
 
        XFS_WANT_CORRUPTED_GOTO(mp,
                have_lt == 0 ||