From: Wu Fengguang Date: Tue, 23 Dec 2008 20:21:30 +0000 (-0500) Subject: nfs: remove redundant tests on reading new pages X-Git-Tag: v2.6.29-rc1~553^2^2~69 X-Git-Url: https://git.kernelconcepts.de/?a=commitdiff_plain;h=136221fc3219b3805c48db5da065e8e3467175d4;p=karo-tx-linux.git nfs: remove redundant tests on reading new pages 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 --- 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);