From fdec10829d87dfa334b6584b6b8882a36b0b0b41 Mon Sep 17 00:00:00 2001 From: Wu Fengguang Date: Tue, 23 Dec 2008 15:21:30 -0500 Subject: nfs: remove redundant tests on reading new pages commit 136221fc3219b3805c48db5da065e8e3467175d4 upstream. aops->readpages() and its NFS helper readpage_async_filler() will only be called to do readahead I/O for newly allocated pages. So it's not necessary to test for the always 0 dirty/uptodate page flags. The removal of nfs_wb_page() call also fixes a readahead bug: the NFS readahead has been synchronous since 2.6.23, because that call will clear PG_readahead, which is the reminder for asynchronous readahead. More background: the PG_readahead page flag is shared with PG_reclaim, one for read path and the other for write path. clear_page_dirty_for_io() unconditionally clears PG_readahead to prevent possible readahead residuals, assuming itself to be always called in the write path. However, NFS is one and the only exception in that it _always_ calls clear_page_dirty_for_io() in the read path, i.e. for readpages()/readpage(). Cc: Trond Myklebust Signed-off-by: Wu Fengguang Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- fs/nfs/read.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'fs') diff --git a/fs/nfs/read.c b/fs/nfs/read.c index 40d17987d0e8..f856004bb7fa 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -533,12 +533,6 @@ readpage_async_filler(void *data, struct page *page) unsigned int len; int error; - error = nfs_wb_page(inode, page); - if (error) - goto out_unlock; - if (PageUptodate(page)) - goto out_unlock; - len = nfs_page_length(page); if (len == 0) return nfs_return_empty_page(page); -- cgit v1.2.3