btrfs: cloned bios must not be iterated by bio_for_each_segment_all
We've started using cloned bios more in 4.13, there are some specifics
regarding the iteration. Filipe found [1] that the raid56 iterated a
cloned bio using bio_for_each_segment_all, which is incorrect. The
cloned bios have wrong bi_vcnt and this could lead to silent
corruptions. This patch adds assertions to all remaining
bio_for_each_segment_all cases.
[1] https://patchwork.kernel.org/patch/9838535/
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b675889..075beed 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -964,6 +964,7 @@
struct btrfs_root *root;
int i, ret = 0;
+ ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, i) {
root = BTRFS_I(bvec->bv_page->mapping->host)->root;
ret = csum_dirty_buffer(root->fs_info, bvec->bv_page);