Commit eca0f6f6 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: subpage: support metadata checksum calculation at write time 



Add a new helper, csum_dirty_subpage_buffers(), to iterate through all
dirty extent buffers in one bvec.

Also extract the code of calculating csum for one extent buffer into
csum_one_extent_buffer(), so that both the existing csum_dirty_buffer()
and the new csum_dirty_subpage_buffers() can reuse the same routine.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 139e8cd3

fs/btrfs/disk-io.c

+72 −24
Original line number Diff line number Diff line
@@ -441,6 +441,74 @@ static int btree_read_extent_buffer_pages(struct extent_buffer *eb, 
	return ret;

}



static int csum_one_extent_buffer(struct extent_buffer *eb)

{

	struct btrfs_fs_info *fs_info = eb->fs_info;

	u8 result[BTRFS_CSUM_SIZE];

	int ret;



	ASSERT(memcmp_extent_buffer(eb, fs_info->fs_devices->metadata_uuid,

				    offsetof(struct btrfs_header, fsid),

				    BTRFS_FSID_SIZE) == 0);

	csum_tree_block(eb, result);



	if (btrfs_header_level(eb))

		ret = btrfs_check_node(eb);

	else

		ret = btrfs_check_leaf_full(eb);



	if (ret < 0) {

		btrfs_print_tree(eb, 0);

		btrfs_err(fs_info,

			"block=%llu write time tree block corruption detected",

			eb->start);

		WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));

		return ret;

	}

	write_extent_buffer(eb, result, 0, fs_info->csum_size);



	return 0;

}



/* Checksum all dirty extent buffers in one bio_vec */

static int csum_dirty_subpage_buffers(struct btrfs_fs_info *fs_info,

				      struct bio_vec *bvec)

{

	struct page *page = bvec->bv_page;

	u64 bvec_start = page_offset(page) + bvec->bv_offset;

	u64 cur;

	int ret = 0;



	for (cur = bvec_start; cur < bvec_start + bvec->bv_len;

	     cur += fs_info->nodesize) {

		struct extent_buffer *eb;

		bool uptodate;



		eb = find_extent_buffer(fs_info, cur);

		uptodate = btrfs_subpage_test_uptodate(fs_info, page, cur,

						       fs_info->nodesize);



		/* A dirty eb shouldn't disappear from buffer_radix */

		if (WARN_ON(!eb))

			return -EUCLEAN;



		if (WARN_ON(cur != btrfs_header_bytenr(eb))) {

			free_extent_buffer(eb);

			return -EUCLEAN;

		}

		if (WARN_ON(!uptodate)) {

			free_extent_buffer(eb);

			return -EUCLEAN;

		}



		ret = csum_one_extent_buffer(eb);

		free_extent_buffer(eb);

		if (ret < 0)

			return ret;

	}

	return ret;

}



/*

 * Checksum a dirty tree block before IO.  This has extra checks to make sure

 * we only fill in the checksum field in the first page of a multi-page block.
@@ -451,9 +519,10 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct bio_vec *bvec 
	struct page *page = bvec->bv_page;

	u64 start = page_offset(page);

	u64 found_start;

	u8 result[BTRFS_CSUM_SIZE];

	struct extent_buffer *eb;

	int ret;



	if (fs_info->sectorsize < PAGE_SIZE)

		return csum_dirty_subpage_buffers(fs_info, bvec);



	eb = (struct extent_buffer *)page->private;

	if (page != eb->pages[0])
@@ -475,28 +544,7 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct bio_vec *bvec 
	if (WARN_ON(!PageUptodate(page)))

		return -EUCLEAN;



	ASSERT(memcmp_extent_buffer(eb, fs_info->fs_devices->metadata_uuid,

				    offsetof(struct btrfs_header, fsid),

				    BTRFS_FSID_SIZE) == 0);



	csum_tree_block(eb, result);



	if (btrfs_header_level(eb))

		ret = btrfs_check_node(eb);

	else

		ret = btrfs_check_leaf_full(eb);



	if (ret < 0) {

		btrfs_print_tree(eb, 0);

		btrfs_err(fs_info,

		"block=%llu write time tree block corruption detected",

			  eb->start);

		WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));

		return ret;

	}

	write_extent_buffer(eb, result, 0, fs_info->csum_size);



	return 0;

	return csum_one_extent_buffer(eb);

}



static int check_tree_block_fsid(struct extent_buffer *eb)