writeback: fix break condition (89e12190) · Commits · 戴 / test

Commit ("write-back: fix nr_to_write counter") fixed nr_to_write counter, but didn't set the break condition properly. If nr_to_write == 0 after being decremented it will loop one more time before setting done = 1 and breaking the loop. [akpm@linux-foundation.org: coding-style fixes] Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Acked-by:

Nick Piggin <npiggin@suse.de> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/page-writeback.c

+16 −13

Original line number	Diff line number	Diff line
		@@ -1051,21 +1051,24 @@ continue_unlock:
		}
		}

		if (nr_to_write > 0)
		if (nr_to_write > 0) {
		nr_to_write--;
		else if (wbc->sync_mode == WB_SYNC_NONE) {
		if (nr_to_write == 0 &&
		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
		* 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;

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