[PATCH][RFC] xfs_copy: don't use DIRECT IO to copy 4k sector device

[Zirong Lang]

----- 原始邮件 -----
> 发件人: "Eric Sandeen" <sandeen at sandeen.net>
> 收件人: "Zorro Lang" <zlang at redhat.com>, xfs at oss.sgi.com
> 发送时间: 星期五, 2015年 8 月 14日 上午 12:23:22
> 主题: Re: [PATCH][RFC] xfs_copy: don't use DIRECT IO to copy 4k sector device
> 
> On 8/13/15 10:07 AM, Zorro Lang wrote:
> > When I run xfstests xfs/032 in ppc64le, I hit a failure:
> > 
> >      xfs_copy: read failed: Invalid argument
> >      xfs_copy: size check failed
> >      xfs_copy: /dev/sda5 filesystem failed to initialize
> >      xfs_copy: Aborting.
> >      Copy failed for Sector size 4096 Block size 4096
> > 
> > I try to use gdb trace xfs_copy. I find it try to open the
> > source device with DIRECT flag, then read the device with
> > ((1<<BBSHIFT))=512 bytes length. If the source device is
> > 4k sector, directly read 512 bytes will be failed.
> > 
> > xfs_copy '-b' option only work for target file/device, to
> > sure it will open the target without DIRECT flag. But useless
> > for source device open.
> > 
> > So I make DIRECT flag only be enabled when source device
> > sector size equal BBSIZE.
> 
> Which version of xfsprogs did you test?  This is recently upstream:

Sorry I didn't notice that you have fix this problem. I test on the
newest version from git://oss.sgi.com/xfs/cmds/xfsprogs, it haven't
fix this problem. I test this patch on it at first. Then I find
there is another version in git://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git

I don't know they are too different, so I didn't check if this xfsprogs-dev has
 fixed it, and just did this patch on it and send out.

Sorry for this mistake, and your patch is really better:)

Thanks,
Zorro Lang

> 
> commit c63ce10a9450020382bbbe2c48788961b19830f4
> Author: Eric Sandeen <sandeen at redhat.com>
> Date:   Fri Jul 31 09:03:11 2015 +1000
> 
>     xfs_copy: fix copy of hard 4k devices
>     
>     If we have a pure 4k device with no 512 emulation, xfs_copy
>     fails straightaway because it tries to do a 512-byte direct
>     IO read of the superblock.
>     
>     Do like we do in xfs_db, and read in the max possible sector size,
>     because we don't yet know what the filesystem's sector size is.
>     
>     This fixes a failure in xfs/032 on a hard 4k device.
> 
> -Eric
> 
> > Signed-off-by: Zorro Lang <zlang at redhat.com>
> > ---
> > 
> > Hi,
> > 
> > I'm not so familiar for xfsprogs, so I'm not sure this's the best
> > idea to fix this problem. Please help to check, and maybe give me
> > better suggestions.
> > 
> > Thanks very much,
> > Zorro Lang
> > 
> >  copy/xfs_copy.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/copy/xfs_copy.c b/copy/xfs_copy.c
> > index e13f468..1cd6253 100644
> > --- a/copy/xfs_copy.c
> > +++ b/copy/xfs_copy.c
> > @@ -666,7 +666,6 @@ main(int argc, char **argv)
> >  	/* prepare the libxfs_init structure */
> >  
> >  	memset(&xargs, 0, sizeof(xargs));
> > -	xargs.isdirect = LIBXFS_DIRECT;
> >  	xargs.isreadonly = LIBXFS_ISREADONLY;
> >  
> >  	if (source_is_file)  {
> > @@ -689,6 +688,8 @@ main(int argc, char **argv)
> >  			     1 << (XFS_MAX_SECTORSIZE_LOG - BBSHIFT), 0, NULL);
> >  	sb = &mbuf.m_sb;
> >  	libxfs_sb_from_disk(sb, XFS_BUF_TO_SBP(sbp));
> > +	if (sb->sb_sectsize == BBSIZE)
> > +		xargs.isdirect = LIBXFS_DIRECT;
> >  
> >  	/* Do it again, now with proper length and verifier */
> >  	libxfs_putbuf(sbp);
> > 
> 
>