Commit 9cf3c389 authored Feb 28, 2014 by Chao Yu Committed by Jaegeuk Kim Feb 28, 2014

f2fs: fix dirty page accounting when redirty



We should de-account dirty counters for page when redirty in ->writepage().

Wu Fengguang described in 'commit 971767ca':
"writeback: fix dirtied pages accounting on redirty
De-account the accumulative dirty counters on page redirty.

Page redirties (very common in ext4) will introduce mismatch between
counters (a) and (b)

a) NR_DIRTIED, BDI_DIRTIED, tsk->nr_dirtied
b) NR_WRITTEN, BDI_WRITTEN

This will introduce systematic errors in balanced_rate and result in
dirty page position errors (ie. the dirty pages are no longer balanced
around the global/bdi setpoints)."

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

parent 695fd1ed

fs/f2fs/checkpoint.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -178,6 +178,7 @@ no_write:
		redirty_out:
		dec_page_count(sbi, F2FS_DIRTY_META);
		wbc->pages_skipped++;
		account_page_redirty(page);
		set_page_dirty(page);
		return AOP_WRITEPAGE_ACTIVATE;
		}

fs/f2fs/data.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -839,6 +839,7 @@ out:

		redirty_out:
		wbc->pages_skipped++;
		account_page_redirty(page);
		set_page_dirty(page);
		return AOP_WRITEPAGE_ACTIVATE;
		}

fs/f2fs/node.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1193,6 +1193,7 @@ static int f2fs_write_node_page(struct page *page,
		redirty_out:
		dec_page_count(sbi, F2FS_DIRTY_NODES);
		wbc->pages_skipped++;
		account_page_redirty(page);
		set_page_dirty(page);
		return AOP_WRITEPAGE_ACTIVATE;
		}

Admin message