From 41bd9ca459a007cc5588563bb08de9677c8d23fd Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Thu, 6 Mar 2014 13:54:57 +0800 Subject: [PATCH] Btrfs: just do dirty page flush for the inode with compression before direct IO As the comment in the btrfs_direct_IO says, only the compressed pages need be flush again to make sure they are on the disk, but the common pages needn't, so we add a if statement to check if the inode has compressed pages or not, if no, skip the flush. And in order to prevent the write ranges from intersecting, we need wait for the running ordered extents. But the current code waits for them twice, one is done before the direct IO starts (in btrfs_wait_ordered_range()), the other is before we get the blocks, it is unnecessary. because we can do the direct IO without holding i_mutex, it means that the intersected ordered extents may happen during the direct IO, the first wait can not avoid this problem. So we use filemap_fdatawrite_range() instead of btrfs_wait_ordered_range() to remove the first wait. Signed-off-by: Miao Xie Signed-off-by: Josef Bacik --- fs/btrfs/inode.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 53697a80b849..f5e623371bf3 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7422,15 +7422,15 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb, smp_mb__after_atomic_inc(); /* - * The generic stuff only does filemap_write_and_wait_range, which isn't - * enough if we've written compressed pages to this area, so we need to - * call btrfs_wait_ordered_range to make absolutely sure that any - * outstanding dirty pages are on disk. + * The generic stuff only does filemap_write_and_wait_range, which + * isn't enough if we've written compressed pages to this area, so + * we need to flush the dirty pages again to make absolutely sure + * that any outstanding dirty pages are on disk. */ count = iov_length(iov, nr_segs); - ret = btrfs_wait_ordered_range(inode, offset, count); - if (ret) - return ret; + if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT, + &BTRFS_I(inode)->runtime_flags)) + filemap_fdatawrite_range(inode->i_mapping, offset, count); if (rw & WRITE) { /* -- 2.20.1