[PATCH 045/145] xfs: enable the xfs_defer mechanism to process rmaps to update

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

Connect the xfs_defer mechanism with the pieces that we'll need to
handle deferred rmap updates.  We'll wire up the existing code to
our new deferred mechanism later.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 libxfs/defer_item.c |  100 +++++++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/xfs_defer.h  |    1 +
 2 files changed, 101 insertions(+)


diff --git a/libxfs/defer_item.c b/libxfs/defer_item.c
index 777875c..cd88cfd 100644
--- a/libxfs/defer_item.c
+++ b/libxfs/defer_item.c
@@ -30,6 +30,7 @@
 #include "xfs_trans.h"
 #include "xfs_bmap.h"
 #include "xfs_alloc.h"
+#include "xfs_rmap_btree.h"
 
 /* Extent Freeing */
 
@@ -126,11 +127,110 @@ const struct xfs_defer_op_type 
xfs_extent_free_defer_type = {
        .cancel_item    = xfs_bmap_free_cancel_item,
 };
 
+/* Reverse Mapping */
+
+/* Sort rmap intents by AG. */
+static int
+xfs_rmap_update_diff_items(
+       void                            *priv,
+       struct list_head                *a,
+       struct list_head                *b)
+{
+       struct xfs_mount                *mp = priv;
+       struct xfs_rmap_intent          *ra;
+       struct xfs_rmap_intent          *rb;
+
+       ra = container_of(a, struct xfs_rmap_intent, ri_list);
+       rb = container_of(b, struct xfs_rmap_intent, ri_list);
+       return  XFS_FSB_TO_AGNO(mp, ra->ri_bmap.br_startblock) -
+               XFS_FSB_TO_AGNO(mp, rb->ri_bmap.br_startblock);
+}
+
+/* Get an RUI. */
+STATIC void *
+xfs_rmap_update_create_intent(
+       struct xfs_trans                *tp,
+       unsigned int                    count)
+{
+       return NULL;
+}
+
+/* Log rmap updates in the intent item. */
+STATIC void
+xfs_rmap_update_log_item(
+       struct xfs_trans                *tp,
+       void                            *intent,
+       struct list_head                *item)
+{
+}
+
+/* Get an RUD so we can process all the deferred rmap updates. */
+STATIC void *
+xfs_rmap_update_create_done(
+       struct xfs_trans                *tp,
+       void                            *intent,
+       unsigned int                    count)
+{
+       return NULL;
+}
+
+/* Process a deferred rmap update. */
+STATIC int
+xfs_rmap_update_finish_item(
+       struct xfs_trans                *tp,
+       struct xfs_defer_ops            *dop,
+       struct list_head                *item,
+       void                            *done_item,
+       void                            **state)
+{
+       return -EFSCORRUPTED;
+}
+
+/* Clean up after processing deferred rmaps. */
+STATIC void
+xfs_rmap_update_finish_cleanup(
+       struct xfs_trans        *tp,
+       void                    *state,
+       int                     error)
+{
+}
+
+/* Abort all pending RUIs. */
+STATIC void
+xfs_rmap_update_abort_intent(
+       void                            *intent)
+{
+}
+
+/* Cancel a deferred rmap update. */
+STATIC void
+xfs_rmap_update_cancel_item(
+       struct list_head                *item)
+{
+       struct xfs_rmap_intent          *rmap;
+
+       rmap = container_of(item, struct xfs_rmap_intent, ri_list);
+       kmem_free(rmap);
+}
+
+const struct xfs_defer_op_type xfs_rmap_update_defer_type = {
+       .type           = XFS_DEFER_OPS_TYPE_RMAP,
+       .diff_items     = xfs_rmap_update_diff_items,
+       .create_intent  = xfs_rmap_update_create_intent,
+       .abort_intent   = xfs_rmap_update_abort_intent,
+       .log_item       = xfs_rmap_update_log_item,
+       .create_done    = xfs_rmap_update_create_done,
+       .finish_item    = xfs_rmap_update_finish_item,
+       .finish_cleanup = xfs_rmap_update_finish_cleanup,
+       .cancel_item    = xfs_rmap_update_cancel_item,
+};
+
 /* Deferred Item Initialization */
 
 /* Initialize the deferred operation types. */
 void
 xfs_defer_init_types(void)
 {
+       xfs_defer_init_op_type(&xfs_rmap_update_defer_type);
        xfs_defer_init_op_type(&xfs_extent_free_defer_type);
 }
diff --git a/libxfs/xfs_defer.h b/libxfs/xfs_defer.h
index 743fc32..920642e 100644
--- a/libxfs/xfs_defer.h
+++ b/libxfs/xfs_defer.h
@@ -51,6 +51,7 @@ struct xfs_defer_pending {
  * find all the space it needs.
  */
 enum xfs_defer_ops_type {
+       XFS_DEFER_OPS_TYPE_RMAP,
        XFS_DEFER_OPS_TYPE_FREE,
        XFS_DEFER_OPS_TYPE_MAX,
 };