Re: [patch] btrfs/raid56: fix and cleanup some error paths

Miao Xie
2013-07-22T08:47:00Z

On mon, 22 Jul 2013 09:55:15 +0300, Dan Carpenter wrote:
> The alloc_rbio() frees "raid_map" and "bbio" on error, so there is a
> potential double free bug in raid56_parity_write(). The
> raid56_parity_write() and raid56_parity_recover() functions should still
> free "raid_map" and "bbio" on error if other errors occur though, so I
> have added some more calls to kfree().
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

From the viewpoint of the readability, it is better to free raid_map and bbio
in the caller, I think. But it is up to you.

Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>

>
> diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> index 0525e13..0db856c 100644
> --- a/fs/btrfs/raid56.c
> +++ b/fs/btrfs/raid56.c
> @@ -1687,11 +1687,8 @@ int raid56_parity_write(struct btrfs_root *root, struct bio *bio,
> struct blk_plug_cb *cb;
>
> rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
> - if (IS_ERR(rbio)) {
> - kfree(raid_map);
> - kfree(bbio);
> + if (IS_ERR(rbio))
> return PTR_ERR(rbio);
> - }
> bio_list_add(&rbio->bio_list, bio);
> rbio->bio_list_bytes = bio->bi_size;
>
> @@ -2041,9 +2038,8 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
> int ret;
>
> rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
> - if (IS_ERR(rbio)) {
> + if (IS_ERR(rbio))
> return PTR_ERR(rbio);
> - }
>
> rbio->read_rebuild = 1;
> bio_list_add(&rbio->bio_list, bio);
> @@ -2052,6 +2048,8 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
> rbio->faila = find_logical_bio_stripe(rbio, bio);
> if (rbio->faila = -1) {
> BUG();
> + kfree(raid_map);
> + kfree(bbio);
> kfree(rbio);
> return -EIO;
> }
> --
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