[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>

diff --git a/fs/buffer.c b/fs/buffer.c
index 904d59d..d1f1b54 100644 (file)
--- 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) {

diff --git a/mm/truncate.c b/mm/truncate.c
index e07b1e6..9bfb8e8 100644 (file)
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/pagemap.h>
 #include <linux/pagevec.h>
+#include <linux/task_io_accounting_ops.h>
 #include <linux/buffer_head.h> /* grr. try_to_release_page,
                                   do_invalidatepage */
 
@@ -69,7 +70,8 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
        if (PagePrivate(page))
                do_invalidatepage(page, 0);
 
-       clear_page_dirty(page);
+       if (test_clear_page_dirty(page))
+               task_io_account_cancelled_write(PAGE_CACHE_SIZE);
        ClearPageUptodate(page);
        ClearPageMappedToDisk(page);
        remove_from_page_cache(page);