From 7dbae9fbde8a2d3accf4b89502d5557bf3905e73 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 28 Jun 2019 19:31:37 -0700 Subject: [PATCH] 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: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_aops.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 1d147ef047f7..84fca91dacf1 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -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); } } -- 2.11.0