Commit b51e6b4b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
Browse files

btrfs: don't use btrfs_bio_ctrl for extent buffer writing 



The btrfs_bio_ctrl machinery is overkill for writing extent_buffers
as we always operate on PAGE_SIZE chunks (or one smaller one for the
subpage case) that are contiguous and are guaranteed to fit into a
single bio.  Replace it with open coded btrfs_bio_alloc, __bio_add_page
and btrfs_submit_bio calls.

Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 81a79b6a

fs/btrfs/extent_io.c

+25 −20
Original line number Diff line number Diff line
@@ -121,9 +121,6 @@ static void submit_one_bio(struct btrfs_bio_ctrl *bio_ctrl) 
	/* Caller should ensure the bio has at least some range added */

	ASSERT(bbio->bio.bi_iter.bi_size);



	if (!is_data_inode(&bbio->inode->vfs_inode))

		bbio->bio.bi_opf |= REQ_META;



	if (btrfs_op(&bbio->bio) == BTRFS_MAP_READ &&

	    bio_ctrl->compress_type != BTRFS_COMPRESS_NONE)

		btrfs_submit_compressed_read(bbio);
@@ -1899,11 +1896,7 @@ static void write_one_subpage_eb(struct extent_buffer *eb, 
	struct btrfs_fs_info *fs_info = eb->fs_info;

	struct page *page = eb->pages[0];

	bool no_dirty_ebs = false;

	struct btrfs_bio_ctrl bio_ctrl = {

		.wbc = wbc,

		.opf = REQ_OP_WRITE | wbc_to_write_flags(wbc),

		.end_io_func = end_bio_subpage_eb_writepage,

	};

	struct btrfs_bio *bbio;



	prepare_eb_write(eb);
@@ -1917,10 +1910,17 @@ static void write_one_subpage_eb(struct extent_buffer *eb, 
	if (no_dirty_ebs)

		clear_page_dirty_for_io(page);



	submit_extent_page(&bio_ctrl, eb->start, page, eb->len,

			   eb->start - page_offset(page));

	bbio = btrfs_bio_alloc(INLINE_EXTENT_BUFFER_PAGES,

			       REQ_OP_WRITE | REQ_META | wbc_to_write_flags(wbc),

			       eb->fs_info, end_bio_subpage_eb_writepage, NULL);

	bbio->bio.bi_iter.bi_sector = eb->start >> SECTOR_SHIFT;

	bbio->inode = BTRFS_I(eb->fs_info->btree_inode);

	bbio->file_offset = eb->start;

	__bio_add_page(&bbio->bio, page, eb->len, eb->start - page_offset(page));

	wbc_account_cgroup_owner(wbc, page, eb->len);

	unlock_page(page);

	submit_one_bio(&bio_ctrl);

	btrfs_submit_bio(bbio, 0);



	/*

	 * Submission finished without problem, if no range of the page is

	 * dirty anymore, we have submitted a page.  Update nr_written in wbc.
@@ -1932,16 +1932,21 @@ static void write_one_subpage_eb(struct extent_buffer *eb, 
static noinline_for_stack void write_one_eb(struct extent_buffer *eb,

					    struct writeback_control *wbc)

{

	u64 disk_bytenr = eb->start;

	struct btrfs_bio *bbio;

	int i, num_pages;

	struct btrfs_bio_ctrl bio_ctrl = {

		.wbc = wbc,

		.opf = REQ_OP_WRITE | wbc_to_write_flags(wbc),

		.end_io_func = end_bio_extent_buffer_writepage,

	};



	prepare_eb_write(eb);



	bbio = btrfs_bio_alloc(INLINE_EXTENT_BUFFER_PAGES,

			       REQ_OP_WRITE | REQ_META | wbc_to_write_flags(wbc),

			       eb->fs_info, end_bio_extent_buffer_writepage,

			       NULL);

	bbio->bio.bi_iter.bi_sector = eb->start >> SECTOR_SHIFT;

	bio_set_dev(&bbio->bio, eb->fs_info->fs_devices->latest_dev->bdev);

	wbc_init_bio(wbc, &bbio->bio);

	bbio->inode = BTRFS_I(eb->fs_info->btree_inode);

	bbio->file_offset = eb->start;



	num_pages = num_extent_pages(eb);

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

		struct page *p = eb->pages[i];
@@ -1949,12 +1954,12 @@ static noinline_for_stack void write_one_eb(struct extent_buffer *eb, 
		lock_page(p);

		clear_page_dirty_for_io(p);

		set_page_writeback(p);

		submit_extent_page(&bio_ctrl, disk_bytenr, p, PAGE_SIZE, 0);

		disk_bytenr += PAGE_SIZE;

		__bio_add_page(&bbio->bio, p, PAGE_SIZE, 0);

		wbc_account_cgroup_owner(wbc, p, PAGE_SIZE);

		wbc->nr_to_write--;

		unlock_page(p);

	}

	submit_one_bio(&bio_ctrl);

	btrfs_submit_bio(bbio, 0);

}



/*