From 1a5b80cf93a2f03486abcb81d1330ab6a58f1a56 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Sat, 18 Aug 2012 10:03:22 +1000 Subject: [PATCH] block: makes bio_split support bio without data discard bio hasn't data attached. We hit a BUG_ON with such bio. This makes bio_split works for such bio. Signed-off-by: Shaohua Li Signed-off-by: NeilBrown --- fs/bio.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/fs/bio.c b/fs/bio.c index 73922abba832..fefa7fab8a8b 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -1500,7 +1500,7 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors) trace_block_split(bdev_get_queue(bi->bi_bdev), bi, bi->bi_sector + first_sectors); - BUG_ON(bi->bi_vcnt != 1); + BUG_ON(bi->bi_vcnt != 1 && bi->bi_vcnt != 0); BUG_ON(bi->bi_idx != 0); atomic_set(&bp->cnt, 3); bp->error = 0; @@ -1510,17 +1510,19 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors) bp->bio2.bi_size -= first_sectors << 9; bp->bio1.bi_size = first_sectors << 9; - bp->bv1 = bi->bi_io_vec[0]; - bp->bv2 = bi->bi_io_vec[0]; - bp->bv2.bv_offset += first_sectors << 9; - bp->bv2.bv_len -= first_sectors << 9; - bp->bv1.bv_len = first_sectors << 9; + if (bi->bi_vcnt != 0) { + bp->bv1 = bi->bi_io_vec[0]; + bp->bv2 = bi->bi_io_vec[0]; + bp->bv2.bv_offset += first_sectors << 9; + bp->bv2.bv_len -= first_sectors << 9; + bp->bv1.bv_len = first_sectors << 9; - bp->bio1.bi_io_vec = &bp->bv1; - bp->bio2.bi_io_vec = &bp->bv2; + bp->bio1.bi_io_vec = &bp->bv1; + bp->bio2.bi_io_vec = &bp->bv2; - bp->bio1.bi_max_vecs = 1; - bp->bio2.bi_max_vecs = 1; + bp->bio1.bi_max_vecs = 1; + bp->bio2.bi_max_vecs = 1; + } bp->bio1.bi_end_io = bio_pair_end_1; bp->bio2.bi_end_io = bio_pair_end_2; -- 2.39.5