From 3eee86c8fd9a9cdeba7afa943ae00bd166e2899a Mon Sep 17 00:00:00 2001
From: Nikolay Borisov <nborisov@suse.com>
Date: Thu, 2 Jul 2020 15:23:31 +0300
Subject: [PATCH] btrfs: don't check for btrfs_device::bdev in btrfs_end_bio

btrfs_map_bio ensures that all submitted bios to devices have valid
btrfs_device::bdev so this check can be removed from btrfs_end_bio. This
check was added in june 2012 597a60fadedf ("Btrfs: don't count I/O
statistic read errors for missing devices") but then in October of the
same year another commit de1ee92ac3bc ("Btrfs: recheck bio against
block device when we map the bio") started checking for the presence of
btrfs_device::bdev before actually issuing the bio.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/volumes.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index fb3502166e29b..98f75f795ff23 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6263,17 +6263,16 @@ static void btrfs_end_bio(struct bio *bio)
 		    bio->bi_status == BLK_STS_TARGET) {
 			struct btrfs_device *dev = btrfs_io_bio(bio)->device;
 
-			if (dev->bdev) {
-				if (bio_op(bio) == REQ_OP_WRITE)
-					btrfs_dev_stat_inc_and_print(dev,
+			ASSERT(dev->bdev);
+			if (bio_op(bio) == REQ_OP_WRITE)
+				btrfs_dev_stat_inc_and_print(dev,
 						BTRFS_DEV_STAT_WRITE_ERRS);
-				else if (!(bio->bi_opf & REQ_RAHEAD))
-					btrfs_dev_stat_inc_and_print(dev,
+			else if (!(bio->bi_opf & REQ_RAHEAD))
+				btrfs_dev_stat_inc_and_print(dev,
 						BTRFS_DEV_STAT_READ_ERRS);
-				if (bio->bi_opf & REQ_PREFLUSH)
-					btrfs_dev_stat_inc_and_print(dev,
+			if (bio->bi_opf & REQ_PREFLUSH)
+				btrfs_dev_stat_inc_and_print(dev,
 						BTRFS_DEV_STAT_FLUSH_ERRS);
-			}
 		}
 	}
 
-- 
2.30.2