1 files changed, 59 insertions, 0 deletions

diff --git a/fs/xfs/xfs_bmap_btree.c b/fs/xfs/xfs_bmap_btree.c
index 23efad29a5cd..cfbdd00045cf 100644
--- a/fs/xfs/xfs_bmap_btree.c
+++ b/fs/xfs/xfs_bmap_btree.c
@@ -2608,3 +2608,62 @@ xfs_check_nostate_extents(
         }
         return 0;
 }
+
+
+STATIC struct xfs_btree_cur *
+xfs_bmbt_dup_cursor(
+        struct xfs_btree_cur    *cur)
+{
+        struct xfs_btree_cur    *new;
+
+        new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
+                        cur->bc_private.b.ip, cur->bc_private.b.whichfork);
+
+        /*
+         * Copy the firstblock, flist, and flags values,
+         * since init cursor doesn't get them.
+         */
+        new->bc_private.b.firstblock = cur->bc_private.b.firstblock;
+        new->bc_private.b.flist = cur->bc_private.b.flist;
+        new->bc_private.b.flags = cur->bc_private.b.flags;
+
+        return new;
+}
+
+static const struct xfs_btree_ops xfs_bmbt_ops = {
+        .dup_cursor             = xfs_bmbt_dup_cursor,
+};
+
+/*
+ * Allocate a new bmap btree cursor.
+ */
+struct xfs_btree_cur *                          /* new bmap btree cursor */
+xfs_bmbt_init_cursor(
+        struct xfs_mount        *mp,            /* file system mount point */
+        struct xfs_trans        *tp,            /* transaction pointer */
+        struct xfs_inode        *ip,            /* inode owning the btree */
+        int                     whichfork)      /* data or attr fork */
+{
+        struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
+        struct xfs_btree_cur    *cur;
+
+        cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP);
+
+        cur->bc_tp = tp;
+        cur->bc_mp = mp;
+        cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
+        cur->bc_btnum = XFS_BTNUM_BMAP;
+        cur->bc_blocklog = mp->m_sb.sb_blocklog;
+
+        cur->bc_ops = &xfs_bmbt_ops;
+
+        cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
+        cur->bc_private.b.ip = ip;
+        cur->bc_private.b.firstblock = NULLFSBLOCK;
+        cur->bc_private.b.flist = NULL;
+        cur->bc_private.b.allocated = 0;
+        cur->bc_private.b.flags = 0;
+        cur->bc_private.b.whichfork = whichfork;
+
+        return cur;
+}