[PATCH 1/2] block: fix handling for BIO_NO_PAGE_REF

[Ming Lei]

Commit 399254aaf489211 ("block: add BIO_NO_PAGE_REF flag") introduces
BIO_NO_PAGE_REF, and once this flag is set for one bio, all pages
in the bio won't be get/put during IO.

However, if one bio is submitted via __blkdev_direct_IO_simple(),
even though BIO_NO_PAGE_REF is set, pages still may be put.

Fixes this issue by avoiding to put pages if BIO_NO_PAGE_REF is
set.

Fixes: 399254aaf489211 ("block: add BIO_NO_PAGE_REF flag")
Signed-off-by: Ming Lei <ming....@redhat.com>
---
 fs/block_dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 24615c76c1d0..bb28e2ead679 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -264,7 +264,8 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct 
iov_iter *iter,
        bio_for_each_segment_all(bvec, &bio, i, iter_all) {
                if (should_dirty && !PageCompound(bvec->bv_page))
                        set_page_dirty_lock(bvec->bv_page);
-               put_page(bvec->bv_page);
+               if (!bio_flagged(&bio, BIO_NO_PAGE_REF))
+                       put_page(bvec->bv_page);
        }
 
        if (unlikely(bio.bi_status))
-- 
2.9.5