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@@ -20,9 +20,9 @@
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#include <linux/vmalloc.h>
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#include <linux/log2.h>
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#include <linux/dm-kcopyd.h>
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+#include <linux/workqueue.h>
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#include "dm-exception-store.h"
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-#include "dm-snap.h"
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#include "dm-bio-list.h"
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#define DM_MSG_PREFIX "snapshots"
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@@ -47,9 +47,79 @@
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*/
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#define MIN_IOS 256
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+#define DM_TRACKED_CHUNK_HASH_SIZE 16
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+#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
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+ (DM_TRACKED_CHUNK_HASH_SIZE - 1))
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+
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+struct exception_table {
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+ uint32_t hash_mask;
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+ unsigned hash_shift;
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+ struct list_head *table;
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+};
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+
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+struct dm_snapshot {
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+ struct rw_semaphore lock;
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+
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+ struct dm_dev *origin;
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+
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+ /* List of snapshots per Origin */
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+ struct list_head list;
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+
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+ /* You can't use a snapshot if this is 0 (e.g. if full) */
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+ int valid;
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+
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+ /* Origin writes don't trigger exceptions until this is set */
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+ int active;
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+
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+ /* Used for display of table */
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+ char type;
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+
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+ mempool_t *pending_pool;
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+
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+ atomic_t pending_exceptions_count;
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+
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+ struct exception_table pending;
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+ struct exception_table complete;
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+
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+ /*
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+ * pe_lock protects all pending_exception operations and access
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+ * as well as the snapshot_bios list.
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+ */
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+ spinlock_t pe_lock;
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+
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+ /* The on disk metadata handler */
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+ struct dm_exception_store *store;
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+
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+ struct dm_kcopyd_client *kcopyd_client;
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+
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+ /* Queue of snapshot writes for ksnapd to flush */
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+ struct bio_list queued_bios;
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+ struct work_struct queued_bios_work;
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+
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+ /* Chunks with outstanding reads */
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+ mempool_t *tracked_chunk_pool;
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+ spinlock_t tracked_chunk_lock;
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+ struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
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+};
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+
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static struct workqueue_struct *ksnapd;
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static void flush_queued_bios(struct work_struct *work);
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+static sector_t chunk_to_sector(struct dm_exception_store *store,
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+ chunk_t chunk)
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+{
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+ return chunk << store->chunk_shift;
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+}
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+
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+static int bdev_equal(struct block_device *lhs, struct block_device *rhs)
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+{
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+ /*
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+ * There is only ever one instance of a particular block
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+ * device so we can compare pointers safely.
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+ */
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+ return lhs == rhs;
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+}
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+
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struct dm_snap_pending_exception {
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struct dm_snap_exception e;
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