Commit 3444a972 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by David Sterba
Browse files

btrfs: Factor out tree->ops->merge_bio_hook call 



In submit_extent_page, there's a visually noisy if statement that, in
the midst of other conditions, does the tree dependency for tree->ops
and tree->ops->merge_bio_hook before calling it, and then another
condition afterwards. If an error is returned from merge_bio_hook,
there's no way to catch it. It's considered a routine "1" return
value instead of a failure.

This patch factors out the dependency check into a new local merge_bio
routine and BUG's on an error. The if statement is less noisy as a side-
effect.

Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
parent 0417341e

fs/btrfs/extent_io.c

+14 −3
Original line number Diff line number Diff line
@@ -2429,6 +2429,19 @@ static int submit_one_bio(int rw, struct bio *bio, int mirror_num, 
	return ret;

}



static int merge_bio(struct extent_io_tree *tree, struct page *page,

		     unsigned long offset, size_t size, struct bio *bio,

		     unsigned long bio_flags)

{

	int ret = 0;

	if (tree->ops && tree->ops->merge_bio_hook)

		ret = tree->ops->merge_bio_hook(page, offset, size, bio,

						bio_flags);

	BUG_ON(ret < 0);

	return ret;



}



static int submit_extent_page(int rw, struct extent_io_tree *tree,

			      struct page *page, sector_t sector,

			      size_t size, unsigned long offset,
@@ -2457,9 +2470,7 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree, 
				sector;



		if (prev_bio_flags != bio_flags || !contig ||

		    (tree->ops && tree->ops->merge_bio_hook &&

		     tree->ops->merge_bio_hook(page, offset, page_size, bio,

					       bio_flags)) ||

		    merge_bio(tree, page, offset, page_size, bio, bio_flags) ||

		    bio_add_page(bio, page, page_size, offset) < page_size) {

			ret = submit_one_bio(rw, bio, mirror_num,

					     prev_bio_flags);

fs/btrfs/inode.c

+3 −2
Original line number Diff line number Diff line
@@ -1425,10 +1425,11 @@ int btrfs_merge_bio_hook(struct page *page, unsigned long offset, 
	map_length = length;

	ret = btrfs_map_block(map_tree, READ, logical,

			      &map_length, NULL, 0);



	/* Will always return 0 or 1 with map_multi == NULL */

	BUG_ON(ret < 0);

	if (map_length < length + size)

		return 1;

	return ret;

	return 0;

}



/*

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