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Date: Tue, 17 Jan 2012 10:33:20 -0600 From: Eric Sandeen <sandeen@...deen.net> To: Dave Chinner <david@...morbit.com> CC: Eric Sandeen <sandeen@...hat.com>, ext4 development <linux-ext4@...r.kernel.org>, Eryu Guan <eguan@...hat.com>, xfs-oss <xfs@....sgi.com> Subject: Re: [PATCH V2] xfstests: make 275 pass On 1/4/12 6:39 PM, Dave Chinner wrote: > On Wed, Jan 04, 2012 at 05:21:00PM -0600, Eric Sandeen wrote: >> On 1/4/12 5:17 PM, Dave Chinner wrote: >>> On Wed, Jan 04, 2012 at 02:54:25PM -0600, Eric Sandeen wrote: >>>> Ok, this is a significant rework of 275, which made too many >>>> assumptions about details of space usage and failed on several >>>> filesystems (it passed on xfs, but only by accident). >>>> >>>> This new version tries to leave about 256k free, then tries >>>> a single 1M IO, and fails only if 0 bytes are written. >>>> >>>> It also sends a lot more to $seq.full for debugging on failure >>>> and fixes a few other stylistic things. >>>> >>>> Signed-off-by: Eric Sandeen <sandeen@...hat.com> >>> >>> I just had another thought about this, Eric.... >>> >>>> +# And at least some of it should succeed. >>>> +_filesize=`du $SCRATCH_MNT/tmp1 | awk '{print $1}'` >>>> +[ $_filesize -eq 0 ] && _fail "write file err: Partial write until enospc failed; wrote 0 bytes." >>> >>> The question that just came to mind was this assumes that allocation >>> succeeded so therefore the partial write succeeded. But that's not >>> necessary the case. The partial write might not succeed leaving the >>> file size as zero, but the underlying FS might not remove all the >>> blocks it allocated (nothing says that it has to). Hence to >>> determine if a partial write succeeded, we also need to check that >>> the file size itself is greater than zero.... >> >> Probably need to read up on what posix says it should do. I think >> what you're saying is that it might leave blocks allocated past EOF? >> That'd be surprising to me, but maybe I misunderstand? > > There's no guarantee that du is even reporting blocks on disk. e.g > for XFS du will also report reserved (in-memory) delalloc space on > the inode and that includes speculative allocation beyond EOF. We > don't have to remove specultive delalloc ranges when a partial write > occurs, so effectively checking du output to see if a partial write > succeeded is not a sufficient test to determine if the partial write > succeeded or not. > > However, if the partial write did succeed then the file size *must* > change to reflect what was written. Hence I suspect all we actually > need here is a file size check... Ok; so would you be happy with just this? # And at least some of it should succeed. _filesize=`ls -l $SCRATCH_MNT/tmp1 | awk '{print $5}'` [ $_filesize -eq 0 ] && _fail "write file err: Partial write until enospc failed; wrote 0 bytes." If so I'll put your reviewed-by on it and get this pushed, ok? -Eric > Cheers, > > Dave. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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