Commit 20970ba6 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: use ext4_da_writepages() for all modes 



Rename ext4_da_writepages() to ext4_writepages() and use it for all
modes.  We still need to iterate over all the pages in the case of
data=journalling, but in the case of nodelalloc/data=ordered (which is
what file systems mounted using ext3 backwards compatibility will use)
this will allow us to use a much more efficient I/O submission path.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent f4afb4f4

fs/ext4/inode.c

+31 −10
Original line number Diff line number Diff line
@@ -1799,7 +1799,7 @@ out: 
 * lock so we have to do some magic.

 *

 * This function can get called via...

 *   - ext4_da_writepages after taking page lock (have journal handle)

 *   - ext4_writepages after taking page lock (have journal handle)

 *   - journal_submit_inode_data_buffers (no journal handle)

 *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)

 *   - grab_page_cache when doing write_begin (have journal handle)
@@ -2217,7 +2217,7 @@ static int mpage_map_and_submit_extent(handle_t *handle, 


/*

 * Calculate the total number of credits to reserve for one writepages

 * iteration. This is called from ext4_da_writepages(). We map an extent of

 * iteration. This is called from ext4_writepages(). We map an extent of

 * upto MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping

 * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +

 * bpp - 1 blocks in bpp different extents.
@@ -2349,7 +2349,16 @@ out: 
	return err;

}



static int ext4_da_writepages(struct address_space *mapping,

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

		       void *data)

{

	struct address_space *mapping = data;

	int ret = ext4_writepage(page, wbc);

	mapping_set_error(mapping, ret);

	return ret;

}



static int ext4_writepages(struct address_space *mapping,

			   struct writeback_control *wbc)

{

	pgoff_t	writeback_index = 0;
@@ -2364,7 +2373,7 @@ static int ext4_da_writepages(struct address_space *mapping, 
	bool done;

	struct blk_plug plug;



	trace_ext4_da_writepages(inode, wbc);

	trace_ext4_writepages(inode, wbc);



	/*

	 * No pages to write? This is mainly a kludge to avoid starting
@@ -2374,13 +2383,23 @@ static int ext4_da_writepages(struct address_space *mapping, 
	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))

		return 0;



	if (ext4_should_journal_data(inode)) {

		struct blk_plug plug;

		int ret;



		blk_start_plug(&plug);

		ret = write_cache_pages(mapping, wbc, __writepage, mapping);

		blk_finish_plug(&plug);

		return ret;

	}



	/*

	 * If the filesystem has aborted, it is read-only, so return

	 * right away instead of dumping stack traces later on that

	 * will obscure the real source of the problem.  We test

	 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because

	 * the latter could be true if the filesystem is mounted

	 * read-only, and in that case, ext4_da_writepages should

	 * read-only, and in that case, ext4_writepages should

	 * *never* be called, so if that ever happens, we would want

	 * the stack trace.

	 */
@@ -2520,7 +2539,7 @@ retry: 
		mapping->writeback_index = mpd.first_page;



out_writepages:

	trace_ext4_da_writepages_result(inode, wbc, ret,

	trace_ext4_writepages_result(inode, wbc, ret,

				     nr_to_write - wbc->nr_to_write);

	return ret;

}
@@ -2769,7 +2788,7 @@ int ext4_alloc_da_blocks(struct inode *inode) 
	 * laptop_mode, not even desirable).  However, to do otherwise

	 * would require replicating code paths in:

	 *

	 * ext4_da_writepages() ->

	 * ext4_writepages() ->

	 *    write_cache_pages() ---> (via passed in callback function)

	 *        __mpage_da_writepage() -->

	 *           mpage_add_bh_to_extent()
@@ -3213,6 +3232,7 @@ static const struct address_space_operations ext4_aops = { 
	.readpage		= ext4_readpage,

	.readpages		= ext4_readpages,

	.writepage		= ext4_writepage,

	.writepages		= ext4_writepages,

	.write_begin		= ext4_write_begin,

	.write_end		= ext4_write_end,

	.bmap			= ext4_bmap,
@@ -3228,6 +3248,7 @@ static const struct address_space_operations ext4_journalled_aops = { 
	.readpage		= ext4_readpage,

	.readpages		= ext4_readpages,

	.writepage		= ext4_writepage,

	.writepages		= ext4_writepages,

	.write_begin		= ext4_write_begin,

	.write_end		= ext4_journalled_write_end,

	.set_page_dirty		= ext4_journalled_set_page_dirty,
@@ -3243,7 +3264,7 @@ static const struct address_space_operations ext4_da_aops = { 
	.readpage		= ext4_readpage,

	.readpages		= ext4_readpages,

	.writepage		= ext4_writepage,

	.writepages		= ext4_da_writepages,

	.writepages		= ext4_writepages,

	.write_begin		= ext4_da_write_begin,

	.write_end		= ext4_da_write_end,

	.bmap			= ext4_bmap,

include/trace/events/ext4.h

+2 −2
Original line number Diff line number Diff line
@@ -281,7 +281,7 @@ DEFINE_EVENT(ext4__write_end, ext4_da_write_end, 
	TP_ARGS(inode, pos, len, copied)

);



TRACE_EVENT(ext4_da_writepages,

TRACE_EVENT(ext4_writepages,

	TP_PROTO(struct inode *inode, struct writeback_control *wbc),



	TP_ARGS(inode, wbc),
@@ -379,7 +379,7 @@ TRACE_EVENT(ext4_da_write_pages_extent, 
		  __entry->flags)

);



TRACE_EVENT(ext4_da_writepages_result,

TRACE_EVENT(ext4_writepages_result,

	TP_PROTO(struct inode *inode, struct writeback_control *wbc,

			int ret, int pages_written),

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