On Mon, Aug 28, 2017 at 09:35:07PM +0200, Christoph Hellwig wrote: > On Mon, Aug 28, 2017 at 11:31:42AM -0700, Darrick J. Wong wrote: > > Hmm... this causes at least a couple of xfstests regressions: > > Oh. Looks like I didn't do a rmap run as none of my runs showed > a regression. > > > xfs/310, because we no longer merge adjacent bmap records. I think the > > solution here is to change the extent count check to allow 2 extents. > > Yeah. > > > xfs/245 because zero-mapping forks are no longer reported as having one > > big "hole" extent; instead zero extents are reported back. How do we > > want to handle this case? > > Hmm. Looks like that is the COW fork, as even the current code > never reports a hole at then end when there are no extents at all. > It does however when we have at least one extent: > > root@brick:/home/hch/work/xfs# uname -a > Linux brick 4.9.0-3-amd64 #1 SMP Debian 4.9.30-2+deb9u2 (2017-06-26) x86_64 GNU/Linux > root@brick:/home/hch/work/xfs# truncate --size 10g foo > root@brick:/home/hch/work/xfs# xfs_bmap foo > foo: no extents > root@brick:/home/hch/work/xfs# fallocate -l 10m foo > root@brick:/home/hch/work/xfs# xfs_bmap foo > foo: > 0: [0..20479]: 786860592..786881071 > 1: [20480..20971519]: hole > > in this case I suspect we should try to treat the COW fork the > same. But let me take a more detailed look at xfs/245 on what's > going on there. Aha, I see, it's only if you pass in -e to xfs_bmap then you get a hole record: $ truncate -s 50m /storage/tmp/a $ xfs_io -c 'bmap -elpv' /storage/tmp/a /storage/tmp/a: EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS 0: [0..102399]: hole 102400 $ xfs_bmap /storage/tmp/a /storage/tmp/a: no extents $ xfs_io -c 'bmap -lpv' /storage/tmp/a /storage/tmp/a: no extents (eesh.) --D > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
