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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: david@fromorbit.com, sandeen@redhat.com,
	linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org,
	Amir Goldstein <amir73il@gmail.com>,
	linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-mm@kvack.org, linux-btrfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, ocfs2-devel@oss.oracle.com
Subject: Re: [PATCH 17/26] vfs: enable remap callers that can handle short operations
Date: Wed, 17 Oct 2018 09:35:37 -0700
Message-ID: <20181017163537.GO28243@magnolia> (raw)
In-Reply-To: <20181017083652.GF16896@infradead.org>

On Wed, Oct 17, 2018 at 01:36:52AM -0700, Christoph Hellwig wrote:
> >  /* Update inode timestamps and remove security privileges when remapping. */
> > @@ -2023,7 +2034,8 @@ loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
> >  {
> >  	loff_t ret;
> >  
> > -	WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP));
> > +	WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
> > +				     REMAP_FILE_CAN_SHORTEN));
> 
> I guess this is where you could actually use REMAP_FILE_VALID_FLAGS..
> 
> >  /* REMAP_FILE flags taken care of by the vfs. */
> > -#define REMAP_FILE_ADVISORY		(0)
> > +#define REMAP_FILE_ADVISORY		(REMAP_FILE_CAN_SHORTEN)
> 
> And btw, they are not 'taken care of by the VFS', they need to be
> taken care of by the fs (possibly using helpers) to take affect,
> but they can be safely ignored.

Ok, I'll update the comment.

> > +		if (!IS_ALIGNED(count, bs)) {
> > +			if (remap_flags & REMAP_FILE_CAN_SHORTEN)
> > +				count = ALIGN_DOWN(count, bs);
> > +			else
> > +				return -EINVAL;
> 
> 			if (!(remap_flags & REMAP_FILE_CAN_SHORTEN))
> 				return -EINVAL;
> 			count = ALIGN_DOWN(count, bs);

Seeing as we return EINVAL on shortened count and !CAN_SHORTEN below
this, I think this can be simplified further:

	if (pos_in + count == size_in) {
		bcount = ALIGN(size_in, bs) - pos_in;
	} else {
		if (!IS_ALIGNED(count, bs))
			count = ALIGN_DOWN(count, bs);
		bcount = count;
	}

--D

  reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-16  3:09 [PATCH v5 00/26] fs: fixes for serious clone/dedupe problems Darrick J. Wong
2018-10-16  3:10 ` [PATCH 01/26] xfs: add a per-xfs trace_printk macro Darrick J. Wong
2018-10-16  3:10 ` [PATCH 02/26] vfs: vfs_clone_file_prep_inodes should return EINVAL for a clone from beyond EOF Darrick J. Wong
2018-10-16  3:10 ` [PATCH 03/26] vfs: check file ranges before cloning files Darrick J. Wong
2018-10-16  3:10 ` [PATCH 04/26] vfs: exit early from zero length remap operations Darrick J. Wong
2018-10-17  8:26   ` Christoph Hellwig
2018-10-16  3:10 ` [PATCH 05/26] vfs: strengthen checking of file range inputs to generic_remap_checks Darrick J. Wong
2018-10-16  3:10 ` [PATCH 06/26] vfs: avoid problematic remapping requests into partial EOF block Darrick J. Wong
2018-10-16  3:10 ` [PATCH 07/26] vfs: skip zero-length dedupe requests Darrick J. Wong
2018-10-16  3:10 ` [PATCH 08/26] vfs: rename vfs_clone_file_prep to be more descriptive Darrick J. Wong
2018-10-16  3:10 ` [PATCH 09/26] vfs: rename clone_verify_area to remap_verify_area Darrick J. Wong
2018-10-16  3:11 ` [PATCH 10/26] vfs: combine the clone and dedupe into a single remap_file_range Darrick J. Wong
2018-10-17  8:28   ` Christoph Hellwig
2018-10-16  3:11 ` [PATCH 11/26] vfs: pass remap flags to generic_remap_file_range_prep Darrick J. Wong
2018-10-17  8:28   ` Christoph Hellwig
2018-10-16  3:11 ` [PATCH 12/26] vfs: pass remap flags to generic_remap_checks Darrick J. Wong
2018-10-17  8:29   ` Christoph Hellwig
2018-10-16  3:19 ` [PATCH 13/26] vfs: create generic_remap_file_range_touch to update inode metadata Darrick J. Wong
2018-10-17  8:33   ` Christoph Hellwig
2018-10-16  3:19 ` [PATCH 14/26] vfs: make remap_file_range functions take and return bytes completed Darrick J. Wong
2018-10-16  3:19 ` [PATCH 15/26] vfs: plumb remap flags through the vfs clone functions Darrick J. Wong
2018-10-16  3:19 ` [PATCH 16/26] vfs: plumb remap flags through the vfs dedupe functions Darrick J. Wong
2018-10-16  3:19 ` [PATCH 17/26] vfs: enable remap callers that can handle short operations Darrick J. Wong
2018-10-17  8:36   ` Christoph Hellwig
2018-10-17 16:35     ` Darrick J. Wong [this message]
2018-10-16  3:20 ` [PATCH 18/26] vfs: hide file range comparison function Darrick J. Wong
2018-10-16  3:20 ` [PATCH 19/26] vfs: clean up generic_remap_file_range_prep return value Darrick J. Wong
2018-10-17  8:37   ` Christoph Hellwig
2018-10-16  3:20 ` [PATCH 20/26] ocfs2: truncate page cache for clone destination file before remapping Darrick J. Wong
2018-10-16  3:20 ` [PATCH 21/26] ocfs2: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-16  3:20 ` [PATCH 22/26] ocfs2: support partial clone range and dedupe range Darrick J. Wong
2018-10-16  3:20 ` [PATCH 23/26] ocfs2: remove ocfs2_reflink_remap_range Darrick J. Wong
2018-10-16  3:20 ` [PATCH 24/26] xfs: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-17  8:37   ` Christoph Hellwig
2018-10-16  3:20 ` [PATCH 25/26] xfs: support returning partial reflink results Darrick J. Wong
2018-10-17  8:40   ` Christoph Hellwig
2018-10-17 16:40     ` Darrick J. Wong
2018-10-16  3:21 ` [PATCH 26/26] xfs: remove redundant remap partial EOF block checks Darrick J. Wong
2018-10-17  8:40   ` Christoph Hellwig

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