linux-ext4 - Re: [PATCH 3/3] 285: Test offsets over 4GB

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Date:	Thu, 30 May 2013 22:49:21 +0200
From:	Jan Kara <jack@...e.cz>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	Jan Kara <jack@...e.cz>, xfs@....sgi.com,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 3/3] 285: Test offsets over 4GB

On Thu 30-05-13 15:05:02, Eric Sandeen wrote:
> On 5/30/13 3:01 PM, Jan Kara wrote:
> > On Thu 30-05-13 08:48:24, Eric Sandeen wrote:
> >> On 5/30/13 7:45 AM, Jan Kara wrote:
> >>> Test whether SEEK_HOLE and SEEK_DATA works correctly with offsets over
> >>> 4GB.
> >>
> >>
> >> Hm, should we add 2T as well while we're at it?
> >>
> >> (and does this cause any new failures?)
> >   Yes, ext4 is broken. I've sent fixes for it yesterday. I'm not sure what
> 
> Argh, sorry I forgot that.  I just want to be careful about more rigorous
> tests making it look like we have regressions in the code.
> 
> > exactly would overflow at 2T ... block counts if signed int is used and
> > blocksize is 1KB?
> 
> Hum ok, where'd I come up with 2T?  :)  never mind that maybe, unless
> there are other potential trouble points we should add (8T? 16T for
> filesystems that can handle it?)
  Yeah, so 8T + something might be interesting and both ext4 & xfs should
handle that fine. 16T + something might be interesting for xfs if it
supports that size. I'll update this patch with these checks.

								Honza
 

> >>> Signed-off-by: Jan Kara <jack@...e.cz>
> >>> ---
> >>>  src/seek_sanity_test.c | 38 ++++++++++++++++++++++++++++++++++++++
> >>>  1 file changed, 38 insertions(+)
> >>>
> >>> diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
> >>> index 7d5868b..55e7ed6 100644
> >>> --- a/src/seek_sanity_test.c
> >>> +++ b/src/seek_sanity_test.c
> >>> @@ -18,6 +18,7 @@
> >>>   */
> >>>  
> >>>  #define _XOPEN_SOURCE 500
> >>> +#define _FILE_OFFSET_BITS 64
> >>>  #include <sys/types.h>
> >>>  #include <sys/stat.h>
> >>>  #include <sys/vfs.h>
> >>> @@ -191,6 +192,42 @@ static int do_lseek(int testnum, int subtest, int fd, int filsz, int origin,
> >>>  	return ret;
> >>>  }
> >>>  
> >>> +/* test a huge file to check for 4G overflows */
> >>> +static int test10(int fd, int testnum)
> >>> +{
> >>> +	char *buf = NULL;
> >>> +	int bufsz = alloc_size;
> >>> +	off_t filsz = 8ULL << 30;	/* 8G */
> >>> +	off_t off = filsz - 2*bufsz;
> >>> +	int ret = -1;
> >>> +
> >>> +	buf = do_malloc(bufsz);
> >>> +	if (!buf)
> >>> +		goto out;
> >>> +	memset(buf, 'a', bufsz);
> >>> +
> >>> +	ret = do_pwrite(fd, buf, bufsz, 0);
> >>> +	if (ret)
> >>> +		goto out;
> >>> +	ret = do_pwrite(fd, buf, bufsz, off);
> >>> +	if (ret)
> >>> +		goto out;
> >>> +
> >>> +	/* offset at the beginning */
> >>> +	ret += do_lseek(testnum,  1, fd, filsz, SEEK_HOLE, 0, bufsz);
> >>> +	ret += do_lseek(testnum,  2, fd, filsz, SEEK_HOLE, 1, bufsz);
> >>> +	ret += do_lseek(testnum,  3, fd, filsz, SEEK_DATA, 0, 0);
> >>> +	ret += do_lseek(testnum,  4, fd, filsz, SEEK_DATA, 1, 1);
> >>> +
> >>> +	/* offset around eof */
> >>> +	ret += do_lseek(testnum,  5, fd, filsz, SEEK_HOLE, off, off + bufsz);
> >>> +	ret += do_lseek(testnum,  6, fd, filsz, SEEK_DATA, off, off);
> >>> +	ret += do_lseek(testnum,  7, fd, filsz, SEEK_DATA, off + 1, off + 1);
> >>> +
> >>> +out:
> >>> +	do_free(buf);
> >>> +	return ret;
> >>> +}
> >>>  /*
> >>>   * test file with unwritten extents, have both dirty and
> >>>   * writeback pages in page cache.
> >>> @@ -577,6 +614,7 @@ struct testrec seek_tests[] = {
> >>>         {  7, test07, "Test file with unwritten extents, only have dirty pages" },
> >>>         {  8, test08, "Test file with unwritten extents, only have unwritten pages" },
> >>>         {  9, test09, "Test file with unwritten extents, have both dirty && unwritten pages" },
> >>> +       { 10, test10, "Test a huge file" },
> >>>  };
> >>>  
> >>>  static int run_test(struct testrec *tr)
> >>>
> >>
> 
-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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