From: Chris Mason <chris.mason@oracle.com>
Date: Thu, 20 Nov 2008 15:46:35 +0000 (-0500)
Subject: Btrfs: only flush down bios for writeback pages
X-Git-Tag: firefly_0821_release~15789^2~11^2~49
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0e6bd956ed238eb2f69386f251847fe3163532e1;p=firefly-linux-kernel-4.4.55.git

Btrfs: only flush down bios for writeback pages

The btrfs write_cache_pages call has a flush function so that it submits
the bio it has been building before it waits on any writeback pages.

This adds a check so that flush only happens on writeback pages.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 3a65c10dce33..87dba8517935 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2462,7 +2462,8 @@ retry:
 			}
 
 			if (wbc->sync_mode != WB_SYNC_NONE) {
-				flush_fn(data);
+				if (PageWriteback(page))
+					flush_fn(data);
 				wait_on_page_writeback(page);
 			}