Unverified Commit 48051149 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!6401 btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve 

Merge Pull Request from: @ci-robot 
 
PR sync from: Zizhi Wo <wozizhi@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/SF7NQLWPILXFHXA2FC2VMUYBN2WFAHQI/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9HK4U 
 
Link:https://gitee.com/openeuler/kernel/pulls/6401

 

Reviewed-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents acaaafd2 d03e0696

fs/btrfs/block-rsv.c

+1 −1
Original line number Diff line number Diff line
@@ -485,7 +485,7 @@ struct btrfs_block_rsv *btrfs_use_block_rsv(struct btrfs_trans_handle *trans, 


	block_rsv = get_block_rsv(trans, root);



	if (unlikely(block_rsv->size == 0))

	if (unlikely(btrfs_block_rsv_size(block_rsv) == 0))

		goto try_reserve;

again:

	ret = btrfs_block_rsv_use_bytes(block_rsv, blocksize);

fs/btrfs/block-rsv.h

+16 −0
Original line number Diff line number Diff line
@@ -90,4 +90,20 @@ static inline void btrfs_unuse_block_rsv(struct btrfs_fs_info *fs_info, 
	btrfs_block_rsv_release(fs_info, block_rsv, 0, NULL);

}



/*

 * Get the size of a block reserve in a context where getting a stale value is

 * acceptable, instead of accessing it directly and trigger data race warning

 * from KCSAN.

 */

static inline u64 btrfs_block_rsv_size(struct btrfs_block_rsv *rsv)

{

	u64 ret;



	spin_lock(&rsv->lock);

	ret = rsv->size;

	spin_unlock(&rsv->lock);



	return ret;

}



#endif /* BTRFS_BLOCK_RSV_H */