Re: Write hang on ARM based target

[Ryusuke Konishi <ryusuke-sG5X7nlA6pw@public.gmane.org>]

On Fri, 19 Jun 2009 03:36:42 +0900 (JST), Ryusuke Konishi <ryusuke-sG5X7nlA6pw@public.gmane.org> wrote:
> Hi,
> On Fri, 12 Jun 2009 13:23:44 +0900 (JST), Ryusuke Konishi wrote:
> > On Tue, 9 Jun 2009 13:04:04 -0600, "Dunphy, Bill" wrote:
> > >  
> > > Ryusuke,
> > > 
> > > I've simplified my test approach by simply copying a single 10 byte file
> > > repeatedly.  When doing so, I get consistent NILFS log output at the
> > > time of hang.  Examination of /proc/sysreq-trigger also shows the copy
> > > process to be in the same state as before (at sys_write).
> >
> > Thank you for sending me the trace log.  I will look into the problem
> > later.
> > 
> > Ryusuke Konishi
> 
> In another thread, I've sent a patch that may cause the hang problem.
> Here, I attach the out-of-tree version of the patch.

s/cause/fix/

Ryusuke

> Does this make a difference in your problem ?
> 
> Thanks,
> Ryusuke Konishi
> --
> 
> diff --git a/fs/dat.c b/fs/dat.c
> index 036b05d..b05d9d4 100644
> --- a/fs/dat.c
> +++ b/fs/dat.c
> @@ -149,15 +149,6 @@ void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
>  	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
>  					     req->pr_entry_bh, kaddr);
>  	entry->de_start = cpu_to_le64(nilfs_mdt_cno(dat));
> -	if (entry->de_blocknr != cpu_to_le64(0) ||
> -	    entry->de_end != cpu_to_le64(NILFS_CNO_MAX)) {
> -		printk(KERN_CRIT
> -		       "%s: vbn = %llu, start = %llu, end = %llu, pbn = %llu\n",
> -		       __func__, (unsigned long long)req->pr_entry_nr,
> -		       (unsigned long long)le64_to_cpu(entry->de_start),
> -		       (unsigned long long)le64_to_cpu(entry->de_end),
> -		       (unsigned long long)le64_to_cpu(entry->de_blocknr));
> -	}
>  	entry->de_blocknr = cpu_to_le64(blocknr);
>  	kunmap_atomic(kaddr, KM_USER0);
>  
> diff --git a/fs/segment.c b/fs/segment.c
> index 3cbb3fe..225d5ae 100644
> --- a/fs/segment.c
> +++ b/fs/segment.c
> @@ -2009,26 +2009,13 @@ static int nilfs_segctor_write(struct nilfs_sc_info *sci,
>  		err = nilfs_segbuf_write(segbuf, &wi);
>  
>  		res = nilfs_segbuf_wait(segbuf, &wi);
> -		err = unlikely(err) ? : res;
> +		err = unlikely(err) ? err : res;
>  		if (unlikely(err))
>  			return err;
>  	}
>  	return 0;
>  }
>  
> -static int nilfs_page_has_uncleared_buffer(struct page *page)
> -{
> -	struct buffer_head *head, *bh;
> -
> -	head = bh = page_buffers(page);
> -	do {
> -		if (buffer_dirty(bh) && !list_empty(&bh->b_assoc_buffers))
> -			return 1;
> -		bh = bh->b_this_page;
> -	} while (bh != head);
> -	return 0;
> -}
> -
>  static void __nilfs_end_page_io(struct page *page, int err)
>  {
>  	if (!err) {
> @@ -2056,12 +2043,11 @@ static void nilfs_end_page_io(struct page *page, int err)
>  	if (!page)
>  		return;
>  
> -	if (buffer_nilfs_node(page_buffers(page)) &&
> -	    nilfs_page_has_uncleared_buffer(page))
> -		/* For b-tree node pages, this function may be called twice
> -		   or more because they might be split in a segment.
> -		   This check assures that cleanup has been done for all
> -		   buffers in a split btnode page. */
> +	if (buffer_nilfs_node(page_buffers(page)) && !PageWriteback(page))
> +		/*
> +		 * For b-tree node pages, this function may be called twice
> +		 * or more because they might be split in a segment.
> +		 */
>  		return;
>  
>  	__nilfs_end_page_io(page, err);
> @@ -2125,7 +2111,7 @@ static void nilfs_segctor_abort_write(struct nilfs_sc_info *sci,
>  			}
>  			if (bh->b_page != fs_page) {
>  				nilfs_end_page_io(fs_page, err);
> -				if (unlikely(fs_page == failed_page))
> +				if (fs_page && fs_page == failed_page)
>  					goto done;
>  				fs_page = bh->b_page;
>  			}
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