md/raid5: refactor raid5 "run"

[safe/jmp/linux-2.6] / drivers / md / dm-snap.h

diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h
index 15fa2ae..d9e62b4 100644 (file)
--- a/drivers/md/dm-snap.h
+++ b/drivers/md/dm-snap.h
@@ -1,6 +1,4 @@
 /*
- * dm-snapshot.c
- *
  * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
  *
  * This file is released under the GPL.
@@ -9,84 +7,25 @@
 #ifndef DM_SNAPSHOT_H
 #define DM_SNAPSHOT_H
 
-#include "dm.h"
+#include <linux/device-mapper.h>
+#include "dm-exception-store.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.
- */
-/* 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.
- */
-struct exception {
-       struct list_head hash_list;
-
-       chunk_t old_chunk;
-       chunk_t new_chunk;
-};
-
-/*
- * Abstraction to handle the meta/layout of exception stores (the
- * COW device).
- */
-struct exception_store {
-
-       /*
-        * Destroys this object when you've finished with it.
-        */
-       void (*destroy) (struct exception_store *store);
-
-       /*
-        * The target shouldn't read the COW device until this is
-        * called.
-        */
-       int (*read_metadata) (struct exception_store *store);
-
-       /*
-        * Find somewhere to store the next exception.
-        */
-       int (*prepare_exception) (struct exception_store *store,
-                                 struct exception *e);
-
-       /*
-        * Update the metadata with this exception.
-        */
-       void (*commit_exception) (struct exception_store *store,
-                                 struct exception *e,
-                                 void (*callback) (void *, int success),
-                                 void *callback_context);
-
-       /*
-        * The snapshot is invalid, note this in the metadata.
-        */
-       void (*drop_snapshot) (struct exception_store *store);
-
-       /*
-        * Return how full the snapshot is.
-        */
-       void (*fraction_full) (struct exception_store *store,
-                              sector_t *numerator,
-                              sector_t *denominator);
-
-       struct dm_snapshot *snap;
-       void *context;
-};
+#define DM_TRACKED_CHUNK_HASH_SIZE     16
+#define DM_TRACKED_CHUNK_HASH(x)       ((unsigned long)(x) & \
+                                        (DM_TRACKED_CHUNK_HASH_SIZE - 1))
 
 struct dm_snapshot {
        struct rw_semaphore lock;
-       struct dm_table *table;
+       struct dm_target *ti;
 
        struct dm_dev *origin;
        struct dm_dev *cow;
@@ -108,8 +47,9 @@ struct dm_snapshot {
        /* Used for display of table */
        char type;
 
-       /* The last percentage we notified */
-       int last_percent;
+       mempool_t *pending_pool;
+
+       atomic_t pending_exceptions_count;
 
        struct exception_table pending;
        struct exception_table complete;
@@ -121,28 +61,19 @@ struct dm_snapshot {
        spinlock_t pe_lock;
 
        /* The on disk metadata handler */
-       struct exception_store store;
+       struct dm_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;
-};
-
-/*
- * Used by the exception stores to load exceptions hen
- * initialising.
- */
-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);
-
-int dm_create_transient(struct exception_store *store);
+       /* Chunks with outstanding reads */
+       mempool_t *tracked_chunk_pool;
+       spinlock_t tracked_chunk_lock;
+       struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
+};
 
 /*
  * Return the number of sectors in the device.