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Diffstat (limited to 'drivers/md/dm-snap.c')
-rw-r--r--drivers/md/dm-snap.c72
1 files changed, 71 insertions, 1 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 467c586e243..bb28f9782bd 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -20,9 +20,9 @@
#include <linux/vmalloc.h>
#include <linux/log2.h>
#include <linux/dm-kcopyd.h>
+#include <linux/workqueue.h>
#include "dm-exception-store.h"
-#include "dm-snap.h"
#include "dm-bio-list.h"
#define DM_MSG_PREFIX "snapshots"
@@ -47,9 +47,79 @@
*/
#define MIN_IOS 256
+#define DM_TRACKED_CHUNK_HASH_SIZE 16
+#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
+ (DM_TRACKED_CHUNK_HASH_SIZE - 1))
+
+struct exception_table {
+ uint32_t hash_mask;
+ unsigned hash_shift;
+ struct list_head *table;
+};
+
+struct dm_snapshot {
+ struct rw_semaphore lock;
+
+ struct dm_dev *origin;
+
+ /* List of snapshots per Origin */
+ struct list_head list;
+
+ /* You can't use a snapshot if this is 0 (e.g. if full) */
+ int valid;
+
+ /* Origin writes don't trigger exceptions until this is set */
+ int active;
+
+ /* Used for display of table */
+ char type;
+
+ mempool_t *pending_pool;
+
+ atomic_t pending_exceptions_count;
+
+ 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 dm_exception_store *store;
+
+ 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;
+
+ /* 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];
+};
+
static struct workqueue_struct *ksnapd;
static void flush_queued_bios(struct work_struct *work);
+static sector_t chunk_to_sector(struct dm_exception_store *store,
+ chunk_t chunk)
+{
+ return chunk << store->chunk_shift;
+}
+
+static int bdev_equal(struct block_device *lhs, struct block_device *rhs)
+{
+ /*
+ * There is only ever one instance of a particular block
+ * device so we can compare pointers safely.
+ */
+ return lhs == rhs;
+}
+
struct dm_snap_pending_exception {
struct dm_snap_exception e;