With switching to use btrfs_bio_clone_partial() to split bio in directIO path, read endio is also adapted to that by recording a iterator in btrfs_bio, however, it breaks those bios which are less than stripe length thus no need to be split and results in NULL pointer dereference. This fixes the issue by recording the required bio iterator in btrfs_bio_clone() which is used to clone non-split bio in directIO path. It doesn't affect other calls of btrfs_bio_clone() because they don't need to use this iterator. This bug was caught by fstests/generic/091. Cc: David Sterba <dsterba@xxxxxxx> Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx> --- Based on David's for-next. Fixes: commit "Btrfs: change how we iterate bios in endio" Have run through fstests without introducing new problems. fs/btrfs/extent_io.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 806e8d6..a91c3a1 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2719,6 +2719,7 @@ struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask) btrfs_bio->csum = NULL; btrfs_bio->csum_allocated = NULL; btrfs_bio->end_io = NULL; + btrfs_bio->iter = bio->bi_iter; } return new; } -- 2.9.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
