From e08748ce01e02f0ec154b141f392ccb9555333f4 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@osdl.org>
Date: Sun, 10 Dec 2006 02:19:31 -0800
Subject: [PATCH] io-accounting: write-cancel accounting

Account for the number of byte writes which this process caused to not happen
after all.

Cc: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Cc: David Wright <daw@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 fs/buffer.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'fs/buffer.c')

diff --git a/fs/buffer.c b/fs/buffer.c
index 904d59d1eb8e..d1f1b54d3108 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2853,8 +2853,13 @@ int try_to_free_buffers(struct page *page)
 		 * could encounter a non-uptodate page, which is unresolvable.
 		 * This only applies in the rare case where try_to_free_buffers
 		 * succeeds but the page is not freed.
+		 *
+		 * Also, during truncate, discard_buffer will have marked all
+		 * the page's buffers clean.  We discover that here and clean
+		 * the page also.
 		 */
-		clear_page_dirty(page);
+		if (test_clear_page_dirty(page))
+			task_io_account_cancelled_write(PAGE_CACHE_SIZE);
 	}
 out:
 	if (buffers_to_free) {
-- 
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