aboutsummaryrefslogtreecommitdiff
path: root/mm
diff options
context:
space:
mode:
authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2009-02-02 18:33:49 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2009-02-03 16:59:08 -0800
commitdcf6a79dda5cc2a2bec183e50d829030c0972aaa (patch)
tree557b2867e7c9df361f50b913936d60d4245cf6f8 /mm
parent5193535517825f9a07967e4868a1103013d0a99d (diff)
downloadlinux-dcf6a79dda5cc2a2bec183e50d829030c0972aaa.tar.gz
write-back: fix nr_to_write counter
Commit 05fe478dd04e02fa230c305ab9b5616669821dd3 introduced some @wbc->nr_to_write breakage. It made the following changes: 1. Decrement wbc->nr_to_write instead of nr_to_write 2. Decrement wbc->nr_to_write _only_ if wbc->sync_mode == WB_SYNC_NONE 3. If synced nr_to_write pages, stop only if if wbc->sync_mode == WB_SYNC_NONE, otherwise keep going. However, according to the commit message, the intention was to only make change 3. Change 1 is a bug. Change 2 does not seem to be necessary, and it breaks UBIFS expectations, so if needed, it should be done separately later. And change 2 does not seem to be documented in the commit message. This patch does the following: 1. Undo changes 1 and 2 2. Add a comment explaining change 3 (it very useful to have comments in _code_, not only in the commit). Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Acked-by: Nick Piggin <npiggin@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page-writeback.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b493db7841d..dc32dae01e5 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1051,13 +1051,22 @@ continue_unlock:
}
}
- if (wbc->sync_mode == WB_SYNC_NONE) {
- wbc->nr_to_write--;
- if (wbc->nr_to_write <= 0) {
- done = 1;
- break;
- }
+ if (nr_to_write > 0)
+ nr_to_write--;
+ else if (wbc->sync_mode == WB_SYNC_NONE) {
+ /*
+ * We stop writing back only if we are not
+ * doing integrity sync. In case of integrity
+ * sync we have to keep going because someone
+ * may be concurrently dirtying pages, and we
+ * might have synced a lot of newly appeared
+ * dirty pages, but have not synced all of the
+ * old dirty pages.
+ */
+ done = 1;
+ break;
}
+
if (wbc->nonblocking && bdi_write_congested(bdi)) {
wbc->encountered_congestion = 1;
done = 1;