[PATCH 22/34] btrfs: support cloned bios in btree_csum_one_bio

[Christoph Hellwig <hch@lst.de>]

To allow splitting bios in btrfs_submit_bio, btree_csum_one_bio needs to
be able to handle cloned bios.  As btree_csum_one_bio is always called
before handing the bio to the block layer that is trivially done by using
bio_for_each_segment instead of bio_for_each_segment_all.  Also switch
the function to take a btrfs_bio and use that to derive the fs_info.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/bio.c     |  2 +-
 fs/btrfs/disk-io.c | 14 ++++++--------
 fs/btrfs/disk-io.h |  2 +-
 3 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c
index 84673f552bb345..c7522ac7e0e71c 100644
--- a/fs/btrfs/bio.c
+++ b/fs/btrfs/bio.c
@@ -441,7 +441,7 @@ static void __btrfs_submit_bio(struct bio *bio, struct btrfs_io_context *bioc,
 static blk_status_t btrfs_bio_csum(struct btrfs_bio *bbio)
 {
 	if (bbio->bio.bi_opf & REQ_META)
-		return btree_csum_one_bio(&bbio->bio);
+		return btree_csum_one_bio(bbio);
 	return btrfs_csum_one_bio(bbio);
 }
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9ad6e85fcee6e9..2ae329b5ce9804 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -438,17 +438,15 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct bio_vec *bvec
 	return csum_one_extent_buffer(eb);
 }
 
-blk_status_t btree_csum_one_bio(struct bio *bio)
+blk_status_t btree_csum_one_bio(struct btrfs_bio *bbio)
 {
-	struct bio_vec *bvec;
-	struct btrfs_root *root;
+	struct btrfs_fs_info *fs_info = bbio->inode->root->fs_info;
+	struct bvec_iter iter;
+	struct bio_vec bv;
 	int ret = 0;
-	struct bvec_iter_all iter_all;
 
-	ASSERT(!bio_flagged(bio, BIO_CLONED));
-	bio_for_each_segment_all(bvec, bio, iter_all) {
-		root = BTRFS_I(bvec->bv_page->mapping->host)->root;
-		ret = csum_dirty_buffer(root->fs_info, bvec);
+	bio_for_each_segment(bv, &bbio->bio, iter) {
+		ret = csum_dirty_buffer(fs_info, &bv);
 		if (ret)
 			break;
 	}
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index ac55f8ec3a31a7..f2dd4c6d9c258b 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -114,7 +114,7 @@ int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
 int btrfs_read_extent_buffer(struct extent_buffer *buf,
 			     struct btrfs_tree_parent_check *check);
 
-blk_status_t btree_csum_one_bio(struct bio *bio);
+blk_status_t btree_csum_one_bio(struct btrfs_bio *bbio);
 int btrfs_alloc_log_tree_node(struct btrfs_trans_handle *trans,
 			      struct btrfs_root *root);
 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
-- 
2.39.0