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>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2e6f69908303..a3122fba54e8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2452,6 +2452,7 @@ static void end_bio_extent_writepage(struct bio *bio)
         u64 end;
         int i;
 
+        ASSERT(!bio_flagged(bio, BIO_CLONED));
         bio_for_each_segment_all(bvec, bio, i) {
                 struct page *page = bvec->bv_page;
                 struct inode *inode = page->mapping->host;
@@ -2522,6 +2523,7 @@ static void end_bio_extent_readpage(struct bio *bio)
         int ret;
         int i;
 
+        ASSERT(!bio_flagged(bio, BIO_CLONED));
         bio_for_each_segment_all(bvec, bio, i) {
                 struct page *page = bvec->bv_page;
                 struct inode *inode = page->mapping->host;
@@ -3675,6 +3677,7 @@ static void end_bio_extent_buffer_writepage(struct bio *bio)
         struct extent_buffer *eb;
         int i, done;
 
+        ASSERT(!bio_flagged(bio, BIO_CLONED));
         bio_for_each_segment_all(bvec, bio, i) {
                 struct page *page = bvec->bv_page;