From 4506cfb6f8cad594ac73e0df2b2961ca10dbd25e Mon Sep 17 00:00:00 2001 From: Ryan Ding Date: Fri, 25 Mar 2016 14:21:06 -0700 Subject: ocfs2: record UNWRITTEN extents when populate write desc To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. There is still one issue in the direct write procedure. phase 1: alloc extent with UNWRITTEN flag phase 2: submit direct data to disk, add zero page to page cache phase 3: clear UNWRITTEN flag when data has been written to disk When there are 2 direct write A(0~3KB),B(4~7KB) writing to the same cluster 0~7KB (cluster size 8KB). Write request A arrive phase 2 first, it will zero the region (4~7KB). Before request A enter to phase 3, request B arrive phase 2, it will zero region (0~3KB). This is just like request B steps request A. To resolve this issue, we should let request B knows this cluster is already under zero, to prevent it from steps the previous write request. This patch will add function ocfs2_unwritten_check() to do this job. It will record all clusters that are under direct write(it will be recorded in the 'ip_unwritten_list' member of inode info), and prevent the later direct write writing to the same cluster to do the zero work again. Signed-off-by: Ryan Ding Reviewed-by: Junxiao Bi Cc: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/inode.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/ocfs2/inode.c') diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c index ba495beff1c2..12f4a9e9800f 100644 --- a/fs/ocfs2/inode.c +++ b/fs/ocfs2/inode.c @@ -1170,6 +1170,9 @@ static void ocfs2_clear_inode(struct inode *inode) mlog_bug_on_msg(!list_empty(&oi->ip_io_markers), "Clear inode of %llu, inode has io markers\n", (unsigned long long)oi->ip_blkno); + mlog_bug_on_msg(!list_empty(&oi->ip_unwritten_list), + "Clear inode of %llu, inode has unwritten extents\n", + (unsigned long long)oi->ip_blkno); ocfs2_extent_map_trunc(inode, 0); -- cgit v1.2.3