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

Chao Yu
2016-10-12T15:24:45Z

Hi Jaegeuk,

On 2016/10/12 6:19, Jaegeuk Kim wrote:
> 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.

Thanks for fixing this, is this panic produced with fault injection?

Thanks,

>
> 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