Re: [PATCH 1/8] f2fs: clear nlink if fail to add_link

Jaegeuk Kim
2016-10-11T22:26:26Z

Hi Chao,

On Tue, Oct 11, 2016 at 10:56:59PM +0800, Chao Yu wrote:
> From: Chao Yu <yuchao0@huawei.com>
>
> We don't need to keep incomplete created inode in cache, so if we fail to
> add link into directory during new inode creation, it's better to set
> nlink of inode to zero, then we can evict inode immediately. Otherwise
> release of nid belong to inode will be delayed until inode cache is being
> shrunk, it may cause a seemingly endless loop while allocating free nids
> in time of testing generic/269 case of fstest suit.
>
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
> fs/f2fs/inode.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index d736989..34ae03c 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -384,6 +384,8 @@ retry:
> f2fs_lock_op(sbi);
> err = remove_inode_page(inode);
> f2fs_unlock_op(sbi);
> + if (err == -ENOENT)
> + err = 0;
> }
>
> /* give more chances, if ENOMEM case */
> @@ -424,6 +426,12 @@ void handle_failed_inode(struct inode *inode)
> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> struct node_info ni;
>
> + /*
> + * clear nlink of inode in order to release resource of inode
> + * immediately.
> + */
> + clear_nlink(inode);

We must call update_inode_page() here to avoid kernel panic.
Otherwise, this inode is kept in the gdirty list, resulting in kernel panic
when flushg dirty inodes, since it was already evicted.

I fixed this and started a round of tests.

Thanks,

> +
> /* don't make bad inode, since it becomes a regular file. */
> unlock_new_inode(inode);
>
> --
> 2.10.1