Commit 564f00f6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block_dev: only write bdev inode on close 



Since 018a17bd ("bdi: reimplement bdev_inode_switch_bdi()") the
block device code writes out all dirty data whenever switching the
backing_dev_info for a block device inode.  But a block device inode can
only be dirtied when it is in use, which means we only have to write it
out on the final blkdev_put, but not when doing a blkdev_get.

Factoring out the write out from the bdi list switch prepares from
removing the list switch later in the series.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent b4caecd4

fs/block_dev.c

+19 −12
Original line number Diff line number Diff line
@@ -49,6 +49,17 @@ inline struct block_device *I_BDEV(struct inode *inode) 
}

EXPORT_SYMBOL(I_BDEV);



static void bdev_write_inode(struct inode *inode)

{

	spin_lock(&inode->i_lock);

	while (inode->i_state & I_DIRTY) {

		spin_unlock(&inode->i_lock);

		WARN_ON_ONCE(write_inode_now(inode, true));

		spin_lock(&inode->i_lock);

	}

	spin_unlock(&inode->i_lock);

}



/*

 * Move the inode from its current bdi to a new bdi.  Make sure the inode

 * is clean before moving so that it doesn't linger on the old bdi.
@@ -56,16 +67,10 @@ EXPORT_SYMBOL(I_BDEV); 
static void bdev_inode_switch_bdi(struct inode *inode,

			struct backing_dev_info *dst)

{

	while (true) {

	spin_lock(&inode->i_lock);

		if (!(inode->i_state & I_DIRTY)) {

	WARN_ON_ONCE(inode->i_state & I_DIRTY);

	inode->i_data.backing_dev_info = dst;

	spin_unlock(&inode->i_lock);

			return;

		}

		spin_unlock(&inode->i_lock);

		WARN_ON_ONCE(write_inode_now(inode, true));

	}

}



/* Kill _all_ buffers and pagecache , dirty or not.. */
@@ -1464,9 +1469,11 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) 
		WARN_ON_ONCE(bdev->bd_holders);

		sync_blockdev(bdev);

		kill_bdev(bdev);

		/* ->release can cause the old bdi to disappear,

		 * so must switch it out first

		/*

		 * ->release can cause the queue to disappear, so flush all

		 * dirty data before.

		 */

		bdev_write_inode(bdev->bd_inode);

		bdev_inode_switch_bdi(bdev->bd_inode,

					&default_backing_dev_info);

	}

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