On Tue, Sep 02, 2014 at 12:05:33PM +0000, Holger Hoffstätte wrote: > > I updated to progs-3.16 and noticed during testing: > > root>losetup > NAME SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE > /dev/loop0 0 0 0 0 /tmp/img > > root>mkfs.btrfs -f /dev/loop0 > Btrfs v3.16 > See http://btrfs.wiki.kernel.org for more information. > > Performing full device TRIM (8.00GiB) ... > Turning ON incompat feature 'extref': increased hardlink limit per file > to 65536 > fs created label (null) on /dev/loop0 > nodesize 16384 leafsize 16384 sectorsize 4096 size 8.00GiB > root>mkdir /tmp/btrfs > root>mount /dev/loop0 /tmp/btrfs > > All fine until here.. > > root>btrfs filesystem df /tmp/btrfs > Data, single: total=8.00MiB, used=64.00KiB > System, DUP: total=8.00MiB, used=16.00KiB > System, single: total=4.00MiB, used=0.00 > Metadata, DUP: total=409.56MiB, used=112.00KiB > Metadata, single: total=8.00MiB, used=0.00
Note that the "single" chunks are empty, and will remain so. [snip] > So where does the confusing initial display come from? I'm running this > against a (very patched) 3.14.17, but don't remember ever seeing this > with btrfs-progs-3.14.2. Your memory is faulty, I'm afraid. It's always done that -- at least since I started using btrfs, several years ago. I believe it comes from mkfs creating a trivial basic filesystem (with the single profiles), and then setting enough flags on it that the kernel can bootstrap it with the desired chunks in it -- but I may be wrong about that. Hugo. -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- Normaliser unix c'est comme pasteuriser le Camembert ---
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