Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6

[karo-tx-linux.git] / drivers / md / dm-snap.h

diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h
index fdec1e2dc87183926cac41e1d62fc961e9aab851..24f9fb73b982d0cd148ef15d56428ba6c7ce6877 100644 (file)
--- a/drivers/md/dm-snap.h
+++ b/drivers/md/dm-snap.h
@@ -10,31 +10,79 @@
 #define DM_SNAPSHOT_H
 
 #include "dm.h"
+#include "dm-bio-list.h"
 #include <linux/blkdev.h>
+#include <linux/workqueue.h>
 
 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 exception {
+struct dm_snap_exception {
        struct list_head hash_list;
 
        chunk_t old_chunk;
        chunk_t new_chunk;
 };
 
+/*
+ * 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).
@@ -56,13 +104,13 @@ struct exception_store {
         * Find somewhere to store the next exception.
         */
        int (*prepare_exception) (struct exception_store *store,
-                                 struct exception *e);
+                                 struct dm_snap_exception *e);
 
        /*
         * Update the metadata with this exception.
         */
        void (*commit_exception) (struct exception_store *store,
-                                 struct exception *e,
+                                 struct dm_snap_exception *e,
                                  void (*callback) (void *, int success),
                                  void *callback_context);
 
@@ -84,7 +132,7 @@ struct exception_store {
 
 struct dm_snapshot {
        struct rw_semaphore lock;
-       struct dm_table *table;
+       struct dm_target *ti;
 
        struct dm_dev *origin;
        struct dm_dev *cow;
@@ -112,10 +160,20 @@ struct dm_snapshot {
        struct exception_table pending;
        struct exception_table complete;
 
+       /*
+        * pe_lock protects all pending_exception operations and access
+        * as well as the snapshot_bios list.
+        */
+       spinlock_t pe_lock;
+
        /* The on disk metadata handler */
        struct exception_store store;
 
-       struct kcopyd_client *kcopyd_client;
+       struct dm_kcopyd_client *kcopyd_client;
+
+       /* Queue of snapshot writes for ksnapd to flush */
+       struct bio_list queued_bios;
+       struct work_struct queued_bios_work;
 };
 
 /*
@@ -128,10 +186,9 @@ int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
  * Constructor and destructor for the default persistent
  * store.
  */
-int dm_create_persistent(struct exception_store *store, uint32_t chunk_size);
+int dm_create_persistent(struct exception_store *store);
 
-int dm_create_transient(struct exception_store *store,
-                       struct dm_snapshot *s, int blocksize);
+int dm_create_transient(struct exception_store *store);
 
 /*
  * Return the number of sectors in the device.