From: Gu JinXiang <gujx@cn.fujitsu.com>
Date: Thu, 19 Oct 2017 09:49:27 +0800
Subject: [PATCH] btrfs: Fix bug for misused dev_t when lookup in dev state
hash table.
Git-commit: d28e649a5c58b779b303c252c66ee84a0f2c3b32
Patch-Mainline: v4.15-rc1
References: FATE#323952, FATE#322506
Fix bug of commit 74d46992e0d9 ("block: replace bi_bdev with a gendisk
pointer and partitions index").
bio_dev(bio) is used to find the dev state in function
__btrfsic_submit_bio. But when dev_state is added to the hashtable, it
is using dev_t of block_device.
bio_dev(bio) returns a dev_t of part0 which is different from dev_t in
block_device(bd_dev). bd_dev in block_device represents the exact
partition.
block_device.bd_dev =
bio->bi_partno (same as block_device.bd_partno) + bio_dev(bio).
When adding a dev_state into hashtable, we use the exact partition dev_t.
So when looking it up, it should also use the exact partition dev_t.
Reproducer of this bug:
Use MOUNT_OPTIONS="-o check_int" and run btrfs/001 in fstests.
Then there will be WARNING like below.
WARNING:
btrfs: attempt to write superblock which references block M @29523968 (sda7 /1111654400/2) which is never written!
Signed-off-by: Gu JinXiang <gujx@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Hannes Reinecke <hare@suse.de>
---
fs/btrfs/check-integrity.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 49cf4d5..eeb7356 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -2814,7 +2814,7 @@ static void __btrfsic_submit_bio(struct bio *bio)
mutex_lock(&btrfsic_mutex);
/* since btrfsic_submit_bio() is also called before
* btrfsic_mount(), this might return NULL */
- dev_state = btrfsic_dev_state_lookup(bio_dev(bio));
+ dev_state = btrfsic_dev_state_lookup(bio_dev(bio) + bio->bi_partno);
if (NULL != dev_state &&
(bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
unsigned int i;
--
1.8.5.6