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Commit 7dbae9fb authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: allow merging ioends over append boundaries 



There is no real problem merging ioends that go beyond i_size into an
ioend that doesn't.  We just need to move the append transaction to the
base ioend.  Also use the opportunity to use a real error code instead
of the magic 1 to cancel the transactions, and write a comment
explaining the scheme.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent 0290d9c1

fs/xfs/xfs_aops.c

+21 −7
Original line number Diff line number Diff line
@@ -300,11 +300,28 @@ xfs_ioend_can_merge( 
		return false;

	if (ioend->io_offset + ioend->io_size != next->io_offset)

		return false;

	if (xfs_ioend_is_append(ioend) != xfs_ioend_is_append(next))

		return false;

	return true;

}



/*

 * If the to be merged ioend has a preallocated transaction for file

 * size updates we need to ensure the ioend it is merged into also

 * has one.  If it already has one we can simply cancel the transaction

 * as it is guaranteed to be clean.

 */

static void

xfs_ioend_merge_append_transactions(

	struct xfs_ioend	*ioend,

	struct xfs_ioend	*next)

{

	if (!ioend->io_append_trans) {

		ioend->io_append_trans = next->io_append_trans;

		next->io_append_trans = NULL;

	} else {

		xfs_setfilesize_ioend(next, -ECANCELED);

	}

}



/* Try to merge adjacent completions. */

STATIC void

xfs_ioend_try_merge(
@@ -313,7 +330,6 @@ xfs_ioend_try_merge( 
{

	struct xfs_ioend	*next_ioend;

	int			ioend_error;

	int			error;



	if (list_empty(more_ioends))

		return;
@@ -327,10 +343,8 @@ xfs_ioend_try_merge( 
			break;

		list_move_tail(&next_ioend->io_list, &ioend->io_list);

		ioend->io_size += next_ioend->io_size;

		if (ioend->io_append_trans) {

			error = xfs_setfilesize_ioend(next_ioend, 1);

			ASSERT(error == 1);

		}

		if (next_ioend->io_append_trans)

			xfs_ioend_merge_append_transactions(ioend, next_ioend);

	}

}