Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (44 commits)
  dm raid1: report fault status
  dm raid1: handle read failures
  dm raid1: fix EIO after log failure
  dm raid1: handle recovery failures
  dm raid1: handle write failures
  dm snapshot: combine consecutive exceptions in memory
  dm: stripe enhanced status return
  dm: stripe trigger event on failure
  dm log: auto load modules
  dm: move deferred bio flushing to workqueue
  dm crypt: use async crypto
  dm crypt: prepare async callback fn
  dm crypt: add completion for async
  dm crypt: add async request mempool
  dm crypt: extract scatterlist processing
  dm crypt: tidy io ref counting
  dm crypt: introduce crypt_write_io_loop
  dm crypt: abstract crypt_write_done
  dm crypt: store sector mapping in dm_crypt_io
  dm crypt: move queue functions
  ...

1 files changed, 48 insertions, 2 deletions

diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h
index 650e0f1f51d8..93bce5d49742 100644
--- a/drivers/md/dm-snap.h
+++ b/drivers/md/dm-snap.h
@@ -16,19 +16,22 @@
 
 struct exception_table {
 	uint32_t hash_mask;
+	unsigned hash_shift;
 	struct list_head *table;
 };
 
 /*
  * The snapshot code deals with largish chunks of the disk at a
- * time. Typically 64k - 256k.
+ * time. Typically 32k - 512k.
  */
-/* FIXME: can we get away with limiting these to a uint32_t ? */
 typedef sector_t chunk_t;
 
 /*
  * An exception is used where an old chunk of data has been
  * replaced by a new one.
+ * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
+ * of chunks that follow contiguously.  Remaining bits hold the number of the
+ * chunk within the device.
  */
 struct dm_snap_exception {
 	struct list_head hash_list;
@@ -38,6 +41,49 @@ struct dm_snap_exception {
 };
 
 /*
+ * Funtions to manipulate consecutive chunks
+ */
+#  if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
+#    define DM_CHUNK_CONSECUTIVE_BITS 8
+#    define DM_CHUNK_NUMBER_BITS 56
+
+static inline chunk_t dm_chunk_number(chunk_t chunk)
+{
+	return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
+}
+
+static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+{
+	return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+{
+	e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
+
+	BUG_ON(!dm_consecutive_chunk_count(e));
+}
+
+#  else
+#    define DM_CHUNK_CONSECUTIVE_BITS 0
+
+static inline chunk_t dm_chunk_number(chunk_t chunk)
+{
+	return chunk;
+}
+
+static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+{
+	return 0;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+{
+}
+
+#  endif
+
+/*
  * Abstraction to handle the meta/layout of exception stores (the
  * COW device).
  */