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Commit 7c8a3554 authored by Jens Axboe's avatar Jens Axboe
Browse files

writeback: ensure that WB_SYNC_NONE writeback with sb pinned is sync 



Even if the writeout itself isn't a data integrity operation, we need
to ensure that the caller doesn't drop the sb umount sem before we
have actually done the writeback.

This is a fixup for commit e913fc82.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 2db4e42e

fs/fs-writeback.c

+11 −5
Original line number Diff line number Diff line
@@ -193,7 +193,8 @@ static void bdi_wait_on_work_clear(struct bdi_work *work) 
}



static void bdi_alloc_queue_work(struct backing_dev_info *bdi,

				 struct wb_writeback_args *args)

				 struct wb_writeback_args *args,

				 int wait)

{

	struct bdi_work *work;
@@ -205,6 +206,8 @@ static void bdi_alloc_queue_work(struct backing_dev_info *bdi, 
	if (work) {

		bdi_work_init(work, args);

		bdi_queue_work(bdi, work);

		if (wait)

			bdi_wait_on_work_clear(work);

	} else {

		struct bdi_writeback *wb = &bdi->wb;
@@ -279,7 +282,7 @@ void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, 
		args.for_background = 1;

	}



	bdi_alloc_queue_work(bdi, &args);

	bdi_alloc_queue_work(bdi, &args, sb_locked);

}



/*
@@ -909,6 +912,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait) 


	while ((work = get_next_work_item(bdi, wb)) != NULL) {

		struct wb_writeback_args args = work->args;

		int post_clear;



		/*

		 * Override sync mode, in case we must wait for completion
@@ -916,11 +920,13 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait) 
		if (force_wait)

			work->args.sync_mode = args.sync_mode = WB_SYNC_ALL;



		post_clear = WB_SYNC_ALL || args.sb_pinned;



		/*

		 * If this isn't a data integrity operation, just notify

		 * that we have seen this work and we are now starting it.

		 */

		if (args.sync_mode == WB_SYNC_NONE)

		if (!post_clear)

			wb_clear_pending(wb, work);



		wrote += wb_writeback(wb, &args);
@@ -929,7 +935,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait) 
		 * This is a data integrity writeback, so only do the

		 * notification when we have completed the work.

		 */

		if (args.sync_mode == WB_SYNC_ALL)

		if (post_clear)

			wb_clear_pending(wb, work);

	}
@@ -1000,7 +1006,7 @@ static void bdi_writeback_all(struct super_block *sb, long nr_pages) 
		if (!bdi_has_dirty_io(bdi))

			continue;



		bdi_alloc_queue_work(bdi, &args);

		bdi_alloc_queue_work(bdi, &args, 0);

	}



	rcu_read_unlock();