On Fri, Apr 15, 2011 at 12:03 AM, Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx> wrote: > On 2011.04.14 at 10:56 -0500, Eric Sandeen wrote: >> On 4/14/11 10:52 AM, Pádraig Brady wrote: >> > On 14/04/11 16:50, Eric Sandeen wrote: >> >> On 4/14/11 9:59 AM, Pádraig Brady wrote: >> >>> On 14/04/11 15:02, Markus Trippelsdorf wrote: >> >>>>>> Hi Pádraig, >> >>>>>> >> >>>>>> here you go: >> >>>>>> + filefrag -v unwritten.withdata >> >>>>>> Filesystem type is: ef53 >> >>>>>> File size of unwritten.withdata is 5120 (2 blocks, blocksize 4096) >> >>>>>> ext logical physical expected length flags >> >>>>>> 0 0 274432 2560 unwritten,eof >> >>>>>> unwritten.withdata: 1 extent found >> >>>>>> >> >>>>>> Please notice that this also happens with ext4 on the same kernel. >> >>>>>> Btrfs is fine. >> >>>>> >> >>>> `filefrag -vs` fixes the issue on both xfs and ext4. >> >>> >> >>> So in summary, currently on (2.6.39-rc3), the following >> >>> will (usually?) report a single unwritten extent, >> >>> on both ext4 and xfs >> >>> >> >>> fallocate -l 10MiB -n k >> >>> dd count=10 if=/dev/urandom conv=notrunc iflag=fullblock of=k >> >>> filefrag -v k # grep for an extent without unwritten || fail >> >> >> >> right, that's what I see too in testing. >> >> >> >> But would the coreutils install have done a preallocation of the destination file? >> >> >> >> Otherwise this looks like a different bug... >> >> >> >>> This particular issue has been discussed so far at: >> >>> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=8411 >> >>> Note there it was stated there that ext4 had this >> >>> fixed as of 2.6.39-rc1, so maybe there is something lurking? >> >> >> >> ext4 got a fix, but not xfs, I guess. My poor brain can't remember, I think I started looking into it, but it's clearly still broken. >> >> >> >> Still, I don't know for sure what happened to Markus - did something preallocate, in his case? >> > >> > Well that preallocate test is failing for him >> > when the source file is either on ext4 or xfs. >> > He noticed the issue initially on XFS when copying >> > none preallocated files, so XFS probably just has >> > the general issue of needing a sync before fiemap, >> > where as EXT4 just has this preallocate one >> > (though I've not seen it myself). >> > >> > cheers, >> > Pádraig. >> > >> >> well, if I simply take the preallocation step out of the testcase, it works fine on xfs without a sync. >> >> So I still don't know what Markus hit... > > Maybe it's delalloc: > > x4 /tmp # dd count=10 if=/dev/urandom conv=notrunc iflag=fullblock of=k > 10+0 records in > 10+0 records out > 5120 bytes (5.1 kB) copied, 0.0021822 s, 2.3 MB/s > x4 /tmp # filefrag -v k > Filesystem type is: 58465342 > File size of k is 5120 (2 blocks, blocksize 4096) > ext logical physical expected length flags > 0 0 0 16 unknown,delalloc,eof > k: 1 extent found > x4 /tmp # sync > x4 /tmp # filefrag -v k > Filesystem type is: 58465342 > File size of k is 5120 (2 blocks, blocksize 4096) > ext logical physical expected length flags > 0 0 26960045 16 eof > k: 1 extent found There is no preallocation in this case. Problem comes when fallocate and dealloc work together. > > -- > Markus > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Best Wishes Yongqiang Yang -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
