[PATCH] dm snapshot: add workqueue (ca3a931f) · Commits · 戴 / test

drivers/md/dm-snap.c

+33 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,9 @@
		*/
		#define SNAPSHOT_PAGES 256

		struct workqueue_struct *ksnapd;
		static void flush_queued_bios(void *data);

		struct pending_exception {
		struct exception e;

		@@ -488,6 +491,7 @@ static int snapshot_ctr(struct dm_target ti, unsigned int argc, char *argv)
		s->active = 0;
		s->last_percent = 0;
		init_rwsem(&s->lock);
		spin_lock_init(&s->pe_lock);
		s->table = ti->table;

		/* Allocate hash table for COW data */
		@@ -523,6 +527,9 @@ static int snapshot_ctr(struct dm_target ti, unsigned int argc, char *argv)
		goto bad6;
		}

		bio_list_init(&s->queued_bios);
		INIT_WORK(&s->queued_bios_work, flush_queued_bios, s);

		/* Add snapshot to the list of snapshots for this origin */
		/* Exceptions aren't triggered till snapshot_resume() is called */
		if (register_snapshot(s)) {
		@@ -561,6 +568,8 @@ static void snapshot_dtr(struct dm_target *ti)
		{
		struct dm_snapshot s = (struct dm_snapshot ) ti->private;

		flush_workqueue(ksnapd);

		/* Prevent further origin writes from using this snapshot. */
		/* After this returns there can be no new kcopyd jobs. */
		unregister_snapshot(s);
		@@ -594,6 +603,19 @@ static void flush_bios(struct bio *bio)
		}
		}

		static void flush_queued_bios(void *data)
		{
		struct dm_snapshot s = (struct dm_snapshot ) data;
		struct bio *queued_bios;
		unsigned long flags;

		spin_lock_irqsave(&s->pe_lock, flags);
		queued_bios = bio_list_get(&s->queued_bios);
		spin_unlock_irqrestore(&s->pe_lock, flags);

		flush_bios(queued_bios);
		}

		/*
		* Error a list of buffers.
		*/
		@@ -1240,8 +1262,17 @@ static int __init dm_snapshot_init(void)
		goto bad5;
		}

		ksnapd = create_singlethread_workqueue("ksnapd");
		if (!ksnapd) {
		DMERR("Failed to create ksnapd workqueue.");
		r = -ENOMEM;
		goto bad6;
		}

		return 0;

		bad6:
		mempool_destroy(pending_pool);
		bad5:
		kmem_cache_destroy(pending_cache);
		bad4:
		@@ -1259,6 +1290,8 @@ static void __exit dm_snapshot_exit(void)
		{
		int r;

		destroy_workqueue(ksnapd);

		r = dm_unregister_target(&snapshot_target);
		if (r)
		DMERR("snapshot unregister failed %d", r);

drivers/md/dm-snap.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -10,7 +10,9 @@
		#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;
		@@ -112,10 +114,20 @@ 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;

		/* Queue of snapshot writes for ksnapd to flush */
		struct bio_list queued_bios;
		struct work_struct queued_bios_work;
		};

		/*

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