From: Ming Lei <ming.lei@redhat.com>
Date: Mon, 18 Dec 2017 20:22:12 +0800
Subject: [PATCH] btrfs: avoid accessing bvec table directly for a cloned bio
Git-commit: c16a8ac3c021f454550f851f5e0772b29a5125b0
Patch-mainline: v4.16-rc1
References: bsc#1104967,FATE#325924
Commit 17347cec15f919901c90(Btrfs: change how we iterate bios in endio)
mentioned that for dio the submitted bio may be fast cloned, we
can't access the bvec table directly for a cloned bio, so use
bio_get_first_bvec() to retrieve the 1st bvec.
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Cc: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Acked: David Sterba <dsterba@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
fs/btrfs/inode.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4d5cb6e93c80..cb1e2d201434 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8015,6 +8015,7 @@ static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
int segs;
int ret;
blk_status_t status;
+ struct bio_vec bvec;
BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
@@ -8030,8 +8031,9 @@ static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
}
segs = bio_segments(failed_bio);
+ bio_get_first_bvec(failed_bio, &bvec);
if (segs > 1 ||
- (failed_bio->bi_io_vec->bv_len > btrfs_inode_sectorsize(inode)))
+ (bvec.bv_len > btrfs_inode_sectorsize(inode)))
read_mode |= REQ_FAILFAST_DEV;
isector = start - btrfs_io_bio(failed_bio)->logical;
--
2.16.4