[V4,10/45] btrfs: avoid to access bvec table directly for a cloned bio

Commit Message

Ming Lei Dec. 18, 2017, 12:22 p.m. UTC

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 <[e-mail]>
Cc: Josef Bacik <[e-mail]>
Cc: David Sterba <[e-mail]>
Cc: [e-mail]
Cc: Liu Bo <[e-mail]>
Reviewed-by: Liu Bo <[e-mail]>
Acked: David Sterba <[e-mail]>
Signed-off-by: Ming Lei <[e-mail]>
---
 fs/btrfs/inode.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Patch

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;