mm: task dirty accounting fix

YAMAMOTO-san noticed that task_dirty_inc doesn't seem to be called properly for
cases where set_page_dirty is not used to dirty a page (eg. mark_buffer_dirty).

Additionally, there is some inconsistency about when task_dirty_inc is
called.  It is used for dirty balancing, however it even gets called for
__set_page_dirty_no_writeback.

So rather than increment it in a set_page_dirty wrapper, move it down to
exactly where the dirty page accounting stats are incremented.

Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 665d446b25bc..ff4d1cdd779b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -777,6 +777,7 @@ static int __set_page_dirty(struct page *page,
                         __inc_zone_page_state(page, NR_FILE_DIRTY);
                         __inc_bdi_stat(mapping->backing_dev_info,
                                         BDI_RECLAIMABLE);
+                        task_dirty_inc(current);
                         task_io_account_write(PAGE_CACHE_SIZE);
                 }
                 radix_tree_tag_set(&mapping->page_tree,