[v8,16/18] ext4: use errseq_t based error handling for reporting data writeback errors

From: Jeff Layton <jlayton@redhat.com>

Add a call to filemap_report_wb_err at the end of ext4_sync_file. This
will ensure that we check and advance the errseq_t in the file, which
allows us to track and report errors on all open fds when they occur.

Note that metadata writeback errors are not yet reported on all fds at
this point. That will be added in a later patch.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 fs/ext4/fsync.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

> -	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
> -		return -EIO;
> +	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
> +		ret = -EIO;
> +		goto out;
> +	}

This just seems to add a call to trace_ext4_sync_file_exit for this
case, which seems unrelated to the patch.

>  	if (ret)
> -		return ret;
> +		goto out;
> +

Same here.

>  	/*
>  	 * data=writeback,ordered:
>  	 *  The caller's filemap_fdatawrite()/wait will sync the data.
> @@ -152,7 +155,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
>  		needs_barrier = true;
>  	ret = jbd2_complete_transaction(journal, commit_tid);
>  	if (needs_barrier) {
> -	issue_flush:
> +issue_flush:
>  		err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);

And while I much prefer your new label placement it also doesn't
seem to belong into this patch.

On Thu, 2017-06-29 at 07:12 -0700, Christoph Hellwig wrote:
> > -	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
> > -		return -EIO;
> > +	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
> > +		ret = -EIO;
> > +		goto out;
> > +	}
> 
> This just seems to add a call to trace_ext4_sync_file_exit for this
> case, which seems unrelated to the patch.
> 
> >  	if (ret)
> > -		return ret;
> > +		goto out;
> > +
> 
> Same here.
> 
> >  	/*
> >  	 * data=writeback,ordered:
> >  	 *  The caller's filemap_fdatawrite()/wait will sync the data.
> > @@ -152,7 +155,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
> >  		needs_barrier = true;
> >  	ret = jbd2_complete_transaction(journal, commit_tid);
> >  	if (needs_barrier) {
> > -	issue_flush:
> > +issue_flush:
> >  		err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
> 
> And while I much prefer your new label placement it also doesn't
> seem to belong into this patch.

I revised the patch description earlier to say:

    While we're at it, ensure we always "goto out" instead of just
    returning directly, so that we always hit the exit tracepoint.

...but I'm fine with taking that out if you prefer.