[085/165] ext4: return correct wbc.nr_to_write in ext4_da_writepages

[Greg KH <gregkh@suse.de>]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

commit 2faf2e19dd0e060eeb32442858ef495ac3083277 upstream (as of v2.6.33-rc3)

When ext4_da_writepages increases the nr_to_write in writeback_control
then it must always re-base the return value.  Originally there was a
(misguided) attempt prevent wbc.nr_to_write from going negative.  In
fact, it's necessary to allow nr_to_write to be negative so that
wb_writeback() can correctly calculate how many pages were actually
written.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 fs/ext4/inode.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3010,8 +3010,7 @@ retry:
 out_writepages:
 	if (!no_nrwrite_index_update)
 		wbc->no_nrwrite_index_update = 0;
-	if (wbc->nr_to_write > nr_to_writebump)
-		wbc->nr_to_write -= nr_to_writebump;
+	wbc->nr_to_write -= nr_to_writebump;
 	wbc->range_start = range_start;
 	trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
 	return ret;