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Date: Mon, 27 Nov 2023 10:14:57 -0800
From: "Darrick J. Wong" <djwong@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: cem@kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 3/9] xfs_copy: actually do directio writes to block
 devices
Message-ID: <20231127181457.GB2766956@frogsfrogsfrogs>
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 <170069442535.1865809.15981356020247666131.stgit@frogsfrogsfrogs>
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On Wed, Nov 22, 2023 at 10:40:32PM -0800, Christoph Hellwig wrote:
> > diff --git a/copy/xfs_copy.c b/copy/xfs_copy.c
> > index 79f65946709..26de6b2ee1c 100644
> > --- a/copy/xfs_copy.c
> > +++ b/copy/xfs_copy.c
> > @@ -854,6 +854,8 @@ main(int argc, char **argv)
> >  					progname, target[i].name, progname);
> >  				exit(1);
> >  			}
> > +			if (!buffered_output)
> > +				open_flags |= O_DIRECT;
> >  		}
> 
> I'd just move this outside of the if/else if chain and do the
> assignment once.

Fixed.

> > @@ -887,20 +889,22 @@ main(int argc, char **argv)
> >  				}
> >  			}
> >  		} else  {
> > -			char	*lb[XFS_MAX_SECTORSIZE] = { NULL };
> > +			char	*lb = memalign(wbuf_align, XFS_MAX_SECTORSIZE);
> >  			off64_t	off;
> >  
> >  			/* ensure device files are sufficiently large */
> > +			memset(lb, 0, XFS_MAX_SECTORSIZE);
> >  
> >  			off = mp->m_sb.sb_dblocks * source_blocksize;
> > +			off -= XFS_MAX_SECTORSIZE;
> > +			if (pwrite(target[i].fd, lb, XFS_MAX_SECTORSIZE, off) < 0)  {
> 
> We should probably check for a short write as well?
> Also this line is a bit long.

Ok, I'll check for short writes and split the error messaging so that it
no longer says "Is target too small?" on EIO.

--D

> 
> 
>