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Commit c4a77a6c authored by Jens Axboe's avatar Jens Axboe
Browse files

writeback: make wb_writeback() take an argument structure 



We need to be able to pass in range_cyclic as well, so instead
of growing yet another argument, split the arguments into a
struct wb_writeback_args structure that we can use internally.
Also makes it easier to just copy all members to an on-stack
struct, since we can't access work after clearing the pending
bit.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent f0fad8a5

fs/fs-writeback.c

+49 −29
Original line number Diff line number Diff line
@@ -34,6 +34,17 @@ 
 */

int nr_pdflush_threads;



/*

 * Passed into wb_writeback(), essentially a subset of writeback_control

 */

struct wb_writeback_args {

	long nr_pages;

	struct super_block *sb;

	enum writeback_sync_modes sync_mode;

	int for_kupdate;

	int range_cyclic;

};



/*

 * Work items for the bdi_writeback threads

 */
@@ -45,9 +56,7 @@ struct bdi_work { 
	unsigned long seen;

	atomic_t pending;



	struct super_block *sb;

	unsigned long nr_pages;

	enum writeback_sync_modes sync_mode;

	struct wb_writeback_args args;



	unsigned long state;

};
@@ -69,9 +78,11 @@ static inline void bdi_work_init(struct bdi_work *work, 
				 struct writeback_control *wbc)

{

	INIT_RCU_HEAD(&work->rcu_head);

	work->sb = wbc->sb;

	work->nr_pages = wbc->nr_to_write;

	work->sync_mode = wbc->sync_mode;

	work->args.sb = wbc->sb;

	work->args.nr_pages = wbc->nr_to_write;

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

	work->args.range_cyclic = wbc->range_cyclic;

	work->args.for_kupdate = 0;

	work->state = WS_USED;

}
@@ -106,7 +117,7 @@ static void bdi_work_free(struct rcu_head *head) 


static void wb_work_complete(struct bdi_work *work)

{

	const enum writeback_sync_modes sync_mode = work->sync_mode;

	const enum writeback_sync_modes sync_mode = work->args.sync_mode;



	/*

	 * For allocated work, we can clear the done/seen bit right here.
@@ -653,17 +664,16 @@ static inline bool over_bground_thresh(void) 
 * older_than_this takes precedence over nr_to_write.  So we'll only write back

 * all dirty pages if they are all attached to "old" mappings.

 */

static long wb_writeback(struct bdi_writeback *wb, long nr_pages,

			 struct super_block *sb,

			 enum writeback_sync_modes sync_mode, int for_kupdate)

static long wb_writeback(struct bdi_writeback *wb,

			 struct wb_writeback_args *args)

{

	struct writeback_control wbc = {

		.bdi			= wb->bdi,

		.sb			= sb,

		.sync_mode		= sync_mode,

		.sb			= args->sb,

		.sync_mode		= args->sync_mode,

		.older_than_this	= NULL,

		.for_kupdate		= for_kupdate,

		.range_cyclic		= 1,

		.for_kupdate		= args->for_kupdate,

		.range_cyclic		= args->range_cyclic,

	};

	unsigned long oldest_jif;

	long wrote = 0;
@@ -673,13 +683,18 @@ static long wb_writeback(struct bdi_writeback *wb, long nr_pages, 
		oldest_jif = jiffies -

				msecs_to_jiffies(dirty_expire_interval * 10);

	}

	if (!wbc.range_cyclic) {

		wbc.range_start = 0;

		wbc.range_end = LLONG_MAX;

	}



	for (;;) {

		/*

		 * Don't flush anything for non-integrity writeback where

		 * no nr_pages was given

		 */

		if (!for_kupdate && nr_pages <= 0 && sync_mode == WB_SYNC_NONE)

		if (!args->for_kupdate && args->nr_pages <= 0 &&

		     args->sync_mode == WB_SYNC_NONE)

			break;



		/*
@@ -687,7 +702,8 @@ static long wb_writeback(struct bdi_writeback *wb, long nr_pages, 
		 * periodic background writeout and we are below the

		 * background dirty threshold, don't do anything

		 */

		if (for_kupdate && nr_pages <= 0 && !over_bground_thresh())

		if (args->for_kupdate && args->nr_pages <= 0 &&

		    !over_bground_thresh())

			break;



		wbc.more_io = 0;
@@ -695,7 +711,7 @@ static long wb_writeback(struct bdi_writeback *wb, long nr_pages, 
		wbc.nr_to_write = MAX_WRITEBACK_PAGES;

		wbc.pages_skipped = 0;

		writeback_inodes_wb(wb, &wbc);

		nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;

		args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;

		wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;



		/*
@@ -749,8 +765,16 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb) 
			global_page_state(NR_UNSTABLE_NFS) +

			(inodes_stat.nr_inodes - inodes_stat.nr_unused);



	if (nr_pages)

		return wb_writeback(wb, nr_pages, NULL, WB_SYNC_NONE, 1);

	if (nr_pages) {

		struct wb_writeback_args args = {

			.nr_pages	= nr_pages,

			.sync_mode	= WB_SYNC_NONE,

			.for_kupdate	= 1,

			.range_cyclic	= 1,

		};



		return wb_writeback(wb, &args);

	}



	return 0;

}
@@ -762,35 +786,31 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait) 
{

	struct backing_dev_info *bdi = wb->bdi;

	struct bdi_work *work;

	long nr_pages, wrote = 0;

	long wrote = 0;



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

		enum writeback_sync_modes sync_mode;



		nr_pages = work->nr_pages;

		struct wb_writeback_args args = work->args;



		/*

		 * Override sync mode, in case we must wait for completion

		 */

		if (force_wait)

			work->sync_mode = sync_mode = WB_SYNC_ALL;

		else

			sync_mode = work->sync_mode;

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



		/*

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

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

		 */

		if (sync_mode == WB_SYNC_NONE)

		if (args.sync_mode == WB_SYNC_NONE)

			wb_clear_pending(wb, work);



		wrote += wb_writeback(wb, nr_pages, work->sb, sync_mode, 0);

		wrote += wb_writeback(wb, &args);



		/*

		 * This is a data integrity writeback, so only do the

		 * notification when we have completed the work.

		 */

		if (sync_mode == WB_SYNC_ALL)

		if (args.sync_mode == WB_SYNC_ALL)

			wb_clear_pending(wb, work);

	}