[Ocfs2-devel] [PATCH] ocfs2: free up write context when direct IO failed

[Junxiao Bi]

On 11/02/2018 05:15 AM, Wengang Wang wrote:

> The write context should also be freed even when direct IO failed.
> Otherwise a memory leak is introduced and entries remain in
> oi->ip_unwritten_list causing the following BUG later in unlink path:
>
> ERROR: bug expression: !list_empty(&oi->ip_unwritten_list)
> ERROR: Clear inode of 215043, inode has unwritten extents
> ...
> Call Trace:
> ? __set_current_blocked+0x42/0x68
> ocfs2_evict_inode+0x91/0x6a0 [ocfs2]
> ? bit_waitqueue+0x40/0x33
> evict+0xdb/0x1af
> iput+0x1a2/0x1f7
> do_unlinkat+0x194/0x28f
> SyS_unlinkat+0x1b/0x2f
> do_syscall_64+0x79/0x1ae
> entry_SYSCALL_64_after_hwframe+0x151/0x0
>
> Signed-off-by: Wengang Wang <wen.gang.wang at oracle.com>
> ---
>   fs/ocfs2/aops.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index 302cd7c..a87ca42d 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -2412,8 +2412,15 @@ static int ocfs2_dio_end_io(struct kiocb *iocb,
>   	/* this io's submitter should not have unlocked this before we could */
>   	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
>   
> -	if (bytes > 0 && private)
> -		ret = ocfs2_dio_end_io_write(inode, private, offset, bytes);
> +	if (private) {
> +		if (bytes > 0) {
> +			ret = ocfs2_dio_end_io_write(inode, private, offset,
> +						     bytes);
> +		} else {
> +			mlog(ML_ERROR, "Direct IO failed, free write ctx");
Is it useful to leave the "bytes" value here? It could be some error code.

Thanks,
Junxiao.
> +			ocfs2_dio_free_write_ctx(inode, private);
> +		}
> +	}
>   
>   	ocfs2_iocb_clear_rw_locked(iocb);
>