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Commit 90768eee authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

fs/mpage.c: factor clean_buffers() out of __mpage_writepage() 



__mpage_writepage() is over 200 lines long, has 20 local variables, four
goto labels and could desperately use simplification.  Splitting
clean_buffers() into a helper function improves matters a little,
removing 20+ lines from it.

Signed-off-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dheeraj Reddy <dheeraj.reddy@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1b938c08

fs/mpage.c

+30 −24
Original line number Diff line number Diff line
@@ -439,6 +439,35 @@ struct mpage_data { 
	unsigned use_writepage;

};



/*

 * We have our BIO, so we can now mark the buffers clean.  Make

 * sure to only clean buffers which we know we'll be writing.

 */

static void clean_buffers(struct page *page, unsigned first_unmapped)

{

	unsigned buffer_counter = 0;

	struct buffer_head *bh, *head;

	if (!page_has_buffers(page))

		return;

	head = page_buffers(page);

	bh = head;



	do {

		if (buffer_counter++ == first_unmapped)

			break;

		clear_buffer_dirty(bh);

		bh = bh->b_this_page;

	} while (bh != head);



	/*

	 * we cannot drop the bh if the page is not uptodate or a concurrent

	 * readpage would fail to serialize with the bh and it would read from

	 * disk before we reach the platter.

	 */

	if (buffer_heads_over_limit && PageUptodate(page))

		try_to_free_buffers(page);

}



static int __mpage_writepage(struct page *page, struct writeback_control *wbc,

		      void *data)

{
@@ -591,30 +620,7 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc, 
		goto alloc_new;

	}



	/*

	 * OK, we have our BIO, so we can now mark the buffers clean.  Make

	 * sure to only clean buffers which we know we'll be writing.

	 */

	if (page_has_buffers(page)) {

		struct buffer_head *head = page_buffers(page);

		struct buffer_head *bh = head;

		unsigned buffer_counter = 0;



		do {

			if (buffer_counter++ == first_unmapped)

				break;

			clear_buffer_dirty(bh);

			bh = bh->b_this_page;

		} while (bh != head);



		/*

		 * we cannot drop the bh if the page is not uptodate

		 * or a concurrent readpage would fail to serialize with the bh

		 * and it would read from disk before we reach the platter.

		 */

		if (buffer_heads_over_limit && PageUptodate(page))

			try_to_free_buffers(page);

	}

	clean_buffers(page, first_unmapped);



	BUG_ON(PageWriteback(page));

	set_page_writeback(page);