dm clone metadata: Use a two phase commit (8fdbfe8d) · Commits · 戴 / test

drivers/md/dm-clone-metadata.c

+37 −9

Original line number	Original line	Diff line number	Diff line
	@@ -127,6 +127,9 @@ struct dm_clone_metadata {
	struct dirty_map dmap[2];		struct dirty_map dmap[2];
	struct dirty_map *current_dmap;		struct dirty_map *current_dmap;

			/* Protected by lock */
			struct dirty_map *committing_dmap;

	/*		/*
	* In core copy of the on-disk bitmap to save constantly doing look ups		* In core copy of the on-disk bitmap to save constantly doing look ups
	* on disk.		* on disk.
	@@ -511,6 +514,7 @@ static int dirty_map_init(struct dm_clone_metadata *cmd)
	}		}

	cmd->current_dmap = &cmd->dmap[0];		cmd->current_dmap = &cmd->dmap[0];
			cmd->committing_dmap = NULL;

	return 0;		return 0;
	}		}
	@@ -775,15 +779,17 @@ static int __flush_dmap(struct dm_clone_metadata cmd, struct dirty_map dmap)
	return 0;		return 0;
	}		}

	int dm_clone_metadata_commit(struct dm_clone_metadata *cmd)		int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd)
	{		{
	int r = -EPERM;		int r = 0;
	struct dirty_map dmap, next_dmap;		struct dirty_map dmap, next_dmap;

	down_write(&cmd->lock);		down_write(&cmd->lock);

	if (cmd->fail_io \|\| dm_bm_is_read_only(cmd->bm))		if (cmd->fail_io \|\| dm_bm_is_read_only(cmd->bm)) {
			r = -EPERM;
	goto out;		goto out;
			}

	/* Get current dirty bitmap */		/* Get current dirty bitmap */
	dmap = cmd->current_dmap;		dmap = cmd->current_dmap;
	@@ -795,7 +801,7 @@ int dm_clone_metadata_commit(struct dm_clone_metadata *cmd)
	* The last commit failed, so we don't have a clean dirty-bitmap to		* The last commit failed, so we don't have a clean dirty-bitmap to
	* use.		* use.
	*/		*/
	if (WARN_ON(next_dmap->changed)) {		if (WARN_ON(next_dmap->changed \|\| cmd->committing_dmap)) {
	r = -EINVAL;		r = -EINVAL;
	goto out;		goto out;
	}		}
	@@ -805,11 +811,33 @@ int dm_clone_metadata_commit(struct dm_clone_metadata *cmd)
	cmd->current_dmap = next_dmap;		cmd->current_dmap = next_dmap;
	spin_unlock_irq(&cmd->bitmap_lock);		spin_unlock_irq(&cmd->bitmap_lock);

	/*		/* Set old dirty bitmap as currently committing */
	* No one is accessing the old dirty bitmap anymore, so we can flush		cmd->committing_dmap = dmap;
	* it.		out:
	*/		up_write(&cmd->lock);
	r = __flush_dmap(cmd, dmap);
			return r;
			}

			int dm_clone_metadata_commit(struct dm_clone_metadata *cmd)
			{
			int r = -EPERM;

			down_write(&cmd->lock);

			if (cmd->fail_io \|\| dm_bm_is_read_only(cmd->bm))
			goto out;

			if (WARN_ON(!cmd->committing_dmap)) {
			r = -EINVAL;
			goto out;
			}

			r = __flush_dmap(cmd, cmd->committing_dmap);
			if (!r) {
			/* Clear committing dmap */
			cmd->committing_dmap = NULL;
			}
	out:		out:
	up_write(&cmd->lock);		up_write(&cmd->lock);

drivers/md/dm-clone-metadata.h

+17 −0

Original line number	Original line	Diff line number	Diff line
	@@ -75,7 +75,23 @@ void dm_clone_metadata_close(struct dm_clone_metadata *cmd);

	/*		/*
	* Commit dm-clone metadata to disk.		* Commit dm-clone metadata to disk.
			*
			* We use a two phase commit:
			*
			* 1. dm_clone_metadata_pre_commit(): Prepare the current transaction for
			* committing. After this is called, all subsequent metadata updates, done
			* through either dm_clone_set_region_hydrated() or
			* dm_clone_cond_set_range(), will be part of the next transaction.
			*
			* 2. dm_clone_metadata_commit(): Actually commit the current transaction to
			* disk and start a new transaction.
			*
			* This allows dm-clone to flush the destination device after step (1) to
			* ensure that all freshly hydrated regions, for which we are updating the
			* metadata, are properly written to non-volatile storage and won't be lost in
			* case of a crash.
	*/		*/
			int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd);
	int dm_clone_metadata_commit(struct dm_clone_metadata *cmd);		int dm_clone_metadata_commit(struct dm_clone_metadata *cmd);

	/*		/*
	@@ -112,6 +128,7 @@ int dm_clone_metadata_abort(struct dm_clone_metadata *cmd);
	* Switches metadata to a read only mode. Once read-only mode has been entered		* Switches metadata to a read only mode. Once read-only mode has been entered
	* the following functions will return -EPERM:		* the following functions will return -EPERM:
	*		*
			* dm_clone_metadata_pre_commit()
	* dm_clone_metadata_commit()		* dm_clone_metadata_commit()
	* dm_clone_set_region_hydrated()		* dm_clone_set_region_hydrated()
	* dm_clone_cond_set_range()		* dm_clone_cond_set_range()

drivers/md/dm-clone-target.c

+6 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1122,8 +1122,13 @@ static int commit_metadata(struct clone *clone)
	goto out;		goto out;
	}		}

	r = dm_clone_metadata_commit(clone->cmd);		r = dm_clone_metadata_pre_commit(clone->cmd);
			if (unlikely(r)) {
			__metadata_operation_failed(clone, "dm_clone_metadata_pre_commit", r);
			goto out;
			}

			r = dm_clone_metadata_commit(clone->cmd);
	if (unlikely(r)) {		if (unlikely(r)) {
	__metadata_operation_failed(clone, "dm_clone_metadata_commit", r);		__metadata_operation_failed(clone, "dm_clone_metadata_commit", r);
	goto out;		goto out;

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