Commit b78b98e0 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
Browse files

btrfs: don't use btrfs_bio_ctrl for extent buffer reading 



The btrfs_bio_ctrl machinery is overkill for reading 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 in a helper function shared between
the subpage and node size >= PAGE_SIZE cases.

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 e9538283

fs/btrfs/extent_io.c

+36 −63
Original line number Diff line number Diff line
@@ -98,22 +98,12 @@ void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info) 
 */

struct btrfs_bio_ctrl {

	struct btrfs_bio *bbio;

	int mirror_num;

	enum btrfs_compression_type compress_type;

	u32 len_to_oe_boundary;

	blk_opf_t opf;

	btrfs_bio_end_io_t end_io_func;

	struct writeback_control *wbc;



	/*

	 * This is for metadata read, to provide the extra needed verification

	 * info.  This has to be provided for submit_one_bio(), as

	 * submit_one_bio() can submit a bio if it ends at stripe boundary.  If

	 * no such parent_check is provided, the metadata can hit false alert at

	 * endio time.

	 */

	struct btrfs_tree_parent_check *parent_check;



	/*

	 * Tell writepage not to lock the state bits for this range, it still

	 * does the unlocking.
@@ -124,7 +114,6 @@ struct btrfs_bio_ctrl { 
static void submit_one_bio(struct btrfs_bio_ctrl *bio_ctrl)

{

	struct btrfs_bio *bbio = bio_ctrl->bbio;

	int mirror_num = bio_ctrl->mirror_num;



	if (!bbio)

		return;
@@ -132,25 +121,14 @@ 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)) {

		if (btrfs_op(&bbio->bio) != BTRFS_MAP_WRITE) {

			/*

			 * For metadata read, we should have the parent_check,

			 * and copy it to bbio for metadata verification.

			 */

			ASSERT(bio_ctrl->parent_check);

			memcpy(&bbio->parent_check,

			       bio_ctrl->parent_check,

			       sizeof(struct btrfs_tree_parent_check));

		}

	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, mirror_num);

		btrfs_submit_compressed_read(bbio, 0);

	else

		btrfs_submit_bio(bbio, mirror_num);

		btrfs_submit_bio(bbio, 0);



	/* The bbio is owned by the end_io handler now */

	bio_ctrl->bbio = NULL;
@@ -4243,6 +4221,36 @@ void set_extent_buffer_uptodate(struct extent_buffer *eb) 
	}

}



static void __read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,

				       struct btrfs_tree_parent_check *check)

{

	int num_pages = num_extent_pages(eb), i;

	struct btrfs_bio *bbio;



	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);

	eb->read_mirror = 0;

	atomic_set(&eb->io_pages, num_pages);

	check_buffer_tree_ref(eb);



	bbio = btrfs_bio_alloc(INLINE_EXTENT_BUFFER_PAGES,

			       REQ_OP_READ | REQ_META, eb->fs_info,

			       end_bio_extent_readpage, 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;

	memcpy(&bbio->parent_check, check, sizeof(*check));

	if (eb->fs_info->nodesize < PAGE_SIZE) {

		__bio_add_page(&bbio->bio, eb->pages[0], eb->len,

			       eb->start - page_offset(eb->pages[0]));

	} else {

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

			ClearPageError(eb->pages[i]);

			__bio_add_page(&bbio->bio, eb->pages[i], PAGE_SIZE, 0);

		}

	}

	btrfs_submit_bio(bbio, mirror_num);

}



static int read_extent_buffer_subpage(struct extent_buffer *eb, int wait,

				      int mirror_num,

				      struct btrfs_tree_parent_check *check)
@@ -4251,11 +4259,6 @@ static int read_extent_buffer_subpage(struct extent_buffer *eb, int wait, 
	struct extent_io_tree *io_tree;

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

	struct extent_state *cached_state = NULL;

	struct btrfs_bio_ctrl bio_ctrl = {

		.opf = REQ_OP_READ,

		.mirror_num = mirror_num,

		.parent_check = check,

	};

	int ret;



	ASSERT(!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags));
@@ -4283,18 +4286,10 @@ static int read_extent_buffer_subpage(struct extent_buffer *eb, int wait, 
		return 0;

	}



	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);

	eb->read_mirror = 0;

	atomic_set(&eb->io_pages, 1);

	check_buffer_tree_ref(eb);

	bio_ctrl.end_io_func = end_bio_extent_readpage;



	btrfs_subpage_clear_error(fs_info, page, eb->start, eb->len);



	btrfs_subpage_start_reader(fs_info, page, eb->start, eb->len);

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

			   eb->start - page_offset(page));

	submit_one_bio(&bio_ctrl);



	__read_extent_buffer_pages(eb, mirror_num, check);

	if (wait != WAIT_COMPLETE) {

		free_extent_state(cached_state);

		return 0;
@@ -4315,11 +4310,6 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num, 
	int locked_pages = 0;

	int all_uptodate = 1;

	int num_pages;

	struct btrfs_bio_ctrl bio_ctrl = {

		.opf = REQ_OP_READ,

		.mirror_num = mirror_num,

		.parent_check = check,

	};



	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))

		return 0;
@@ -4369,24 +4359,7 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num, 
		goto unlock_exit;

	}



	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);

	eb->read_mirror = 0;

	atomic_set(&eb->io_pages, num_pages);

	/*

	 * It is possible for release_folio to clear the TREE_REF bit before we

	 * set io_pages. See check_buffer_tree_ref for a more detailed comment.

	 */

	check_buffer_tree_ref(eb);

	bio_ctrl.end_io_func = end_bio_extent_readpage;

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

		page = eb->pages[i];



		ClearPageError(page);

		submit_extent_page(&bio_ctrl, page_offset(page), page,

				   PAGE_SIZE, 0);

	}



	submit_one_bio(&bio_ctrl);

	__read_extent_buffer_pages(eb, mirror_num, check);



	if (wait != WAIT_COMPLETE)

		return 0;