linux-kernel - Re: [PATCH v1 1/1] ubifs: only check replay with inode type to judge if inode linked

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Date:   Wed, 7 Apr 2021 23:56:36 +0200
From:   Richard Weinberger <richard.weinberger@...il.com>
To:     guochun.mao@...iatek.com
Cc:     Richard Weinberger <richard@....at>,
        Matthias Brugger <matthias.bgg@...il.com>,
        linux-mtd@...ts.infradead.org, LKML <linux-kernel@...r.kernel.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com
Subject: Re: [PATCH v1 1/1] ubifs: only check replay with inode type to judge
 if inode linked

On Tue, Mar 16, 2021 at 10:00 AM <guochun.mao@...iatek.com> wrote:
>
> From: Guochun Mao <guochun.mao@...iatek.com>
>
> Conside the following case, it just write a big file into flash,
> when complete writing, delete the file, and then power off promptly.
> Next time power on, we'll get a replay list like:
> ...
> LEB 1105:211344 len 4144 deletion 0 sqnum 428783 key type 1 inode 80
> LEB 15:233544 len 160 deletion 1 sqnum 428785 key type 0 inode 80
> LEB 1105:215488 len 4144 deletion 0 sqnum 428787 key type 1 inode 80
> ...
> In the replay list, data nodes' deletion are 0, and the inode node's
> deletion is 1. In current logic, the file's dentry will be removed,
> but inode and the flash space it occupied will be reserved.
> User will see that much free space been disappeared.
>
> We only need to check the deletion value of the following inode type
> node of the replay entry.
>
> Signed-off-by: Guochun Mao <guochun.mao@...iatek.com>
> ---
>  fs/ubifs/replay.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c
> index 0f8a6a16421b..1929ec63a0cb 100644
> --- a/fs/ubifs/replay.c
> +++ b/fs/ubifs/replay.c
> @@ -223,7 +223,8 @@ static bool inode_still_linked(struct ubifs_info *c, struct replay_entry *rino)
>          */
>         list_for_each_entry_reverse(r, &c->replay_list, list) {
>                 ubifs_assert(c, r->sqnum >= rino->sqnum);
> -               if (key_inum(c, &r->key) == key_inum(c, &rino->key))
> +               if (key_inum(c, &r->key) == key_inum(c, &rino->key) &&
> +                   key_type(c, &r->key) == UBIFS_INO_KEY)

This change makes sense. Thanks a lot for hunting this down.
It will be part of the merge window.

-- 
Thanks,
//richard