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Commit 3c4d7165 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

writeback: queue work on stack in writeback_inodes_sb 



If we want to rely on s_umount in the caller we need to wait for completion
of the I/O submission before returning to the caller.  Refactor
bdi_sync_writeback into a bdi_queue_work_onstack helper and use it for this
case.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 7f0e7bed

fs/fs-writeback.c

+21 −19
Original line number Diff line number Diff line
@@ -178,30 +178,22 @@ static void bdi_alloc_queue_work(struct backing_dev_info *bdi, 
}



/**

 * bdi_sync_writeback - start and wait for writeback

 * @bdi: the backing device to write from

 * bdi_queue_work_onstack - start and wait for writeback

 * @sb: write inodes from this super_block

 *

 * Description:

 *   This does WB_SYNC_ALL data integrity writeback and waits for the

 *   IO to complete. Callers must hold the sb s_umount semaphore for

 *   This function initiates writeback and waits for the operation to

 *   complete. Callers must hold the sb s_umount semaphore for

 *   reading, to avoid having the super disappear before we are done.

 */

static void bdi_sync_writeback(struct backing_dev_info *bdi,

			       struct super_block *sb)

static void bdi_queue_work_onstack(struct wb_writeback_args *args)

{

	struct wb_writeback_args args = {

		.sb		= sb,

		.sync_mode	= WB_SYNC_ALL,

		.nr_pages	= LONG_MAX,

		.range_cyclic	= 0,

	};

	struct bdi_work work;



	bdi_work_init(&work, &args);

	bdi_work_init(&work, args);

	__set_bit(WS_ONSTACK, &work.state);



	bdi_queue_work(bdi, &work);

	bdi_queue_work(args->sb->s_bdi, &work);

	bdi_wait_on_work_done(&work);

}
@@ -944,7 +936,7 @@ int bdi_writeback_task(struct bdi_writeback *wb) 


/*

 * Schedule writeback for all backing devices. This does WB_SYNC_NONE

 * writeback, for integrity writeback see bdi_sync_writeback().

 * writeback, for integrity writeback see bdi_queue_work_onstack().

 */

static void bdi_writeback_all(struct super_block *sb, long nr_pages)

{
@@ -1183,12 +1175,15 @@ void writeback_inodes_sb(struct super_block *sb) 
{

	unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);

	unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);

	long nr_to_write;

	struct wb_writeback_args args = {

		.sb		= sb,

		.sync_mode	= WB_SYNC_NONE,

	};



	nr_to_write = nr_dirty + nr_unstable +

	args.nr_pages = nr_dirty + nr_unstable +

			(inodes_stat.nr_inodes - inodes_stat.nr_unused);



	bdi_start_writeback(sb->s_bdi, sb, nr_to_write);

	bdi_queue_work_onstack(&args);

}

EXPORT_SYMBOL(writeback_inodes_sb);
@@ -1218,7 +1213,14 @@ EXPORT_SYMBOL(writeback_inodes_sb_if_idle); 
 */

void sync_inodes_sb(struct super_block *sb)

{

	bdi_sync_writeback(sb->s_bdi, sb);

	struct wb_writeback_args args = {

		.sb		= sb,

		.sync_mode	= WB_SYNC_ALL,

		.nr_pages	= LONG_MAX,

		.range_cyclic	= 0,

	};



	bdi_queue_work_onstack(&args);

	wait_sb_inodes(sb);

}

EXPORT_SYMBOL(sync_inodes_sb);