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Commit 97498956 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: clear the dirty bit for a page in writeback at the last minute 



Move when we call clear_page_dirty_for_io() to just before we actually
write the page.  This simplifies the code somewhat, and avoids marking
pages as clean and then needing to remark them as dirty later.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 4f01b02c

fs/ext4/inode.c

+11 −17
Original line number Diff line number Diff line
@@ -2060,7 +2060,7 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd, 
		if (nr_pages == 0)

			break;

		for (i = 0; i < nr_pages; i++) {

			int commit_write = 0, redirty_page = 0;

			int commit_write = 0, skip_page = 0;

			struct page *page = pvec.pages[i];



			index = page->index;
@@ -2086,14 +2086,12 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd, 
			 * If the page does not have buffers (for

			 * whatever reason), try to create them using

			 * __block_write_begin.  If this fails,

			 * redirty the page and move on.

			 * skip the page and move on.

			 */

			if (!page_has_buffers(page)) {

				if (__block_write_begin(page, 0, len,

						noalloc_get_block_write)) {

				redirty_page:

					redirty_page_for_writepage(mpd->wbc,

								   page);

				skip_page:

					unlock_page(page);

					continue;

				}
@@ -2104,7 +2102,7 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd, 
			block_start = 0;

			do {

				if (!bh)

					goto redirty_page;

					goto skip_page;

				if (map && (cur_logical >= map->m_lblk) &&

				    (cur_logical <= (map->m_lblk +

						     (map->m_len - 1)))) {
@@ -2120,22 +2118,23 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd, 
					clear_buffer_unwritten(bh);

				}



				/* redirty page if block allocation undone */

				/* skip page if block allocation undone */

				if (buffer_delay(bh) || buffer_unwritten(bh))

					redirty_page = 1;

					skip_page = 1;

				bh = bh->b_this_page;

				block_start += bh->b_size;

				cur_logical++;

				pblock++;

			} while (bh != page_bufs);



			if (redirty_page)

				goto redirty_page;

			if (skip_page)

				goto skip_page;



			if (commit_write)

				/* mark the buffer_heads as dirty & uptodate */

				block_commit_write(page, 0, len);



			clear_page_dirty_for_io(page);

			/*

			 * Delalloc doesn't support data journalling,

			 * but eventually maybe we'll lift this
@@ -2277,9 +2276,8 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd) 
		err = blks;

		/*

		 * If get block returns EAGAIN or ENOSPC and there

		 * appears to be free blocks we will call

		 * ext4_writepage() for all of the pages which will

		 * just redirty the pages.

		 * appears to be free blocks we will just let

		 * mpage_da_submit_io() unlock all of the pages.

		 */

		if (err == -EAGAIN)

			goto submit_io;
@@ -2777,7 +2775,6 @@ static int write_cache_pages_da(struct address_space *mapping, 
			    (PageWriteback(page) &&

			     (wbc->sync_mode == WB_SYNC_NONE)) ||

			    unlikely(page->mapping != mapping)) {

			continue_unlock:

				unlock_page(page);

				continue;

			}
@@ -2786,8 +2783,6 @@ static int write_cache_pages_da(struct address_space *mapping, 
				wait_on_page_writeback(page);



			BUG_ON(PageWriteback(page));

			if (!clear_page_dirty_for_io(page))

				goto continue_unlock;



			/*

			 * Can we merge this page to current extent?
@@ -2803,7 +2798,6 @@ static int write_cache_pages_da(struct address_space *mapping, 
					/*

					 * skip rest of the page in the page_vec

					 */

					redirty_page_for_writepage(wbc, page);

					unlock_page(page);

					goto ret_extent_tail;

				}