Commit 9ff8ec32 authored by Steven Whitehouse's avatar Steven Whitehouse
Browse files

[GFS2] Split gfs2_writepage into three cases 



This patch splits gfs2_writepage into separate functions for each of
the three cases: writeback, ordered and journalled. As a result
it becomes a lot easier to see what each one is doing. The common
code is moved into gfs2_writepage_common.

This fixes a performance bug where we were doing more work than
strictly required in the ordered write case.

Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 5561093e

fs/gfs2/lops.c

+10 −7
Original line number Diff line number Diff line
@@ -556,6 +556,7 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le) 


	lock_buffer(bd->bd_bh);

	gfs2_log_lock(sdp);

	if (tr) {

		if (!list_empty(&bd->bd_list_tr))

			goto out;

		tr->tr_touched = 1;
@@ -563,9 +564,11 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le) 
			tr->tr_num_buf++;

			list_add(&bd->bd_list_tr, &tr->tr_list_buf);

		}

	}

	if (!list_empty(&le->le_list))

		goto out;



	if (tr)

		__glock_lo_add(sdp, &bd->bd_gl->gl_le);

	if (gfs2_is_jdata(ip)) {

		gfs2_pin(sdp, bd->bd_bh);

fs/gfs2/ops_address.c

+91 −21
Original line number Diff line number Diff line
@@ -103,16 +103,15 @@ static int gfs2_get_block_direct(struct inode *inode, sector_t lblock, 
}



/**

 * gfs2_writepage - Write complete page

 * @page: Page to write

 *

 * Returns: errno

 * gfs2_writepage_common - Common bits of writepage

 * @page: The page to be written

 * @wbc: The writeback control

 *

 * Some of this is copied from block_write_full_page() although we still

 * call it to do most of the work.

 * Returns: 1 if writepage is ok, otherwise an error code or zero if no error.

 */



static int gfs2_writepage(struct page *page, struct writeback_control *wbc)

static int gfs2_writepage_common(struct page *page,

				 struct writeback_control *wbc)

{

	struct inode *inode = page->mapping->host;

	struct gfs2_inode *ip = GFS2_I(inode);
@@ -120,24 +119,95 @@ static int gfs2_writepage(struct page *page, struct writeback_control *wbc) 
	loff_t i_size = i_size_read(inode);

	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;

	unsigned offset;

	int error;

	int done_trans = 0;

	int ret = -EIO;



	if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {

		unlock_page(page);

		return -EIO;

	}

	if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))

		goto out;

	ret = 0;

	if (current->journal_info)

		goto out_ignore;



		goto redirty;

	/* Is the page fully outside i_size? (truncate in progress) */

	offset = i_size & (PAGE_CACHE_SIZE-1);

	if (page->index > end_index || (page->index == end_index && !offset)) {

		page->mapping->a_ops->invalidatepage(page, 0);

		goto out;

	}

	return 1;

redirty:

	redirty_page_for_writepage(wbc, page);

out:

	unlock_page(page);

		return 0; /* don't care */

	return 0;

}



/**

 * gfs2_writeback_writepage - Write page for writeback mappings

 * @page: The page

 * @wbc: The writeback control

 *

 */



static int gfs2_writeback_writepage(struct page *page,

				    struct writeback_control *wbc)

{

	int ret;



	ret = gfs2_writepage_common(page, wbc);

	if (ret <= 0)

		return ret;



	ret = mpage_writepage(page, gfs2_get_block_noalloc, wbc);

	if (ret == -EAGAIN)

		ret = block_write_full_page(page, gfs2_get_block_noalloc, wbc);

	return ret;

}



/**

 * gfs2_ordered_writepage - Write page for ordered data files

 * @page: The page to write

 * @wbc: The writeback control

 *

 */



static int gfs2_ordered_writepage(struct page *page,

				  struct writeback_control *wbc)

{

	struct inode *inode = page->mapping->host;

	struct gfs2_inode *ip = GFS2_I(inode);

	int ret;



	ret = gfs2_writepage_common(page, wbc);

	if (ret <= 0)

		return ret;



	if (!page_has_buffers(page)) {

		create_empty_buffers(page, inode->i_sb->s_blocksize,

				     (1 << BH_Dirty)|(1 << BH_Uptodate));

	}

	gfs2_page_add_databufs(ip, page, 0, inode->i_sb->s_blocksize-1);

	return block_write_full_page(page, gfs2_get_block_noalloc, wbc);

}



/**

 * gfs2_jdata_writepage - Write complete page

 * @page: Page to write

 *

 * Returns: errno

 *

 */



static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)

{

	struct inode *inode = page->mapping->host;

	struct gfs2_inode *ip = GFS2_I(inode);

	struct gfs2_sbd *sdp = GFS2_SB(inode);

	int error;

	int done_trans = 0;



	error = gfs2_writepage_common(page, wbc);

	if (error <= 0)

		return error;



	if (PageChecked(page)) {

		error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);

		if (error)
@@ -838,7 +908,7 @@ cannot_release: 
}



static const struct address_space_operations gfs2_writeback_aops = {

	.writepage = gfs2_writepage,

	.writepage = gfs2_writeback_writepage,

	.writepages = gfs2_writeback_writepages,

	.readpage = gfs2_readpage,

	.readpages = gfs2_readpages,
@@ -852,7 +922,7 @@ static const struct address_space_operations gfs2_writeback_aops = { 
};



static const struct address_space_operations gfs2_ordered_aops = {

	.writepage = gfs2_writepage,

	.writepage = gfs2_ordered_writepage,

	.readpage = gfs2_readpage,

	.readpages = gfs2_readpages,

	.sync_page = block_sync_page,
@@ -866,7 +936,7 @@ static const struct address_space_operations gfs2_ordered_aops = { 
};



static const struct address_space_operations gfs2_jdata_aops = {

	.writepage = gfs2_writepage,

	.writepage = gfs2_jdata_writepage,

	.readpage = gfs2_readpage,

	.readpages = gfs2_readpages,

	.sync_page = block_sync_page,

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