[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>

1 files changed, 6 insertions, 1 deletions

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) {