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Commit f63e6005 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: Simplify delalloc code by removing mpage_da_writepages() 



The mpage_da_writepages() function is only used in one place, so
inline it to simplify the call stack and make the code easier to
understand.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 8dc207c0

fs/ext4/inode.c

+32 −42
Original line number Diff line number Diff line
@@ -2241,47 +2241,6 @@ static int __mpage_da_writepage(struct page *page, 
	return 0;

}



/*

 * mpage_da_writepages - walk the list of dirty pages of the given

 * address space, allocates non-allocated blocks, maps newly-allocated

 * blocks to existing bhs and issue IO them

 *

 * @mapping: address space structure to write

 * @wbc: subtract the number of written pages from *@wbc->nr_to_write

 *

 * This is a library function, which implements the writepages()

 * address_space_operation.

 */

static int mpage_da_writepages(struct address_space *mapping,

			       struct writeback_control *wbc,

			       struct mpage_da_data *mpd)

{

	int ret;



	mpd->b_size = 0;

	mpd->b_state = 0;

	mpd->b_blocknr = 0;

	mpd->first_page = 0;

	mpd->next_page = 0;

	mpd->io_done = 0;

	mpd->pages_written = 0;

	mpd->retval = 0;



	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);

	/*

	 * Handle last extent of pages

	 */

	if (!mpd->io_done && mpd->next_page != mpd->first_page) {

		if (mpage_da_map_blocks(mpd) == 0)

			mpage_da_submit_io(mpd);



		mpd->io_done = 1;

		ret = MPAGE_DA_EXTENT_TAIL;

	}

	wbc->nr_to_write -= mpd->pages_written;

	return ret;

}



/*

 * this is a special callback for ->write_begin() only

 * it's intention is to return mapped block or reserve space
@@ -2571,7 +2530,38 @@ retry: 
			dump_stack();

			goto out_writepages;

		}

		ret = mpage_da_writepages(mapping, wbc, &mpd);



		/*

		 * Now call __mpage_da_writepage to find the next

		 * contiguous region of logical blocks that need

		 * blocks to be allocated by ext4.  We don't actually

		 * submit the blocks for I/O here, even though

		 * write_cache_pages thinks it will, and will set the

		 * pages as clean for write before calling

		 * __mpage_da_writepage().

		 */

		mpd.b_size = 0;

		mpd.b_state = 0;

		mpd.b_blocknr = 0;

		mpd.first_page = 0;

		mpd.next_page = 0;

		mpd.io_done = 0;

		mpd.pages_written = 0;

		mpd.retval = 0;

		ret = write_cache_pages(mapping, wbc, __mpage_da_writepage,

					&mpd);

		/*

		 * If we have a contigous extent of pages and we

		 * haven't done the I/O yet, map the blocks and submit

		 * them for I/O.

		 */

		if (!mpd.io_done && mpd.next_page != mpd.first_page) {

			if (mpage_da_map_blocks(&mpd) == 0)

				mpage_da_submit_io(&mpd);

			mpd.io_done = 1;

			ret = MPAGE_DA_EXTENT_TAIL;

		}

		wbc->nr_to_write -= mpd.pages_written;



		ext4_journal_stop(handle);