On 6/9/16 11:36 AM, Eric Sandeen wrote: > Ok, this more or less works; not really up to snuff > for submission or merging, just sketching it out, but some > questions first: > > 1) Is there really any point to this? :) We did have one > request, and btrfs can do it ... > > 2) Is using m_growlock horrible? growfs is the only other > thing that writes all supers, so I grabbed it. We don't > want multiple relabels stepping on each other. > > 3) Is there some way to actually force the primary to disk? > Right now the label change isn't actually visible on the > primary until unmount, which defeats the purpose. I'm not > sure if there's a straightforward/safe way to make it > visible... Oh, sorry - I guess it is getting written out, but it's only available via an O_DIRECT read from userspace; it's not invalidating the cache. # io/xfs_io -c "label derp" /mnt/test label = "derp" # dd if=/dev/sdb2 bs=512 count=1 | hexdump -C ... 00000060 00 00 0a 00 b4 e5 02 00 02 00 00 08 66 6f 6f 00 |............foo.| ... # dd if=/dev/sdb2 iflag=direct bs=512 count=1 | hexdump -C ... 00000060 00 00 0a 00 b4 e5 02 00 02 00 00 08 64 65 72 70 |............derp| ... # dd if=/dev/sdb2 bs=512 count=1 | hexdump -C ... 00000060 00 00 0a 00 b4 e5 02 00 02 00 00 08 66 6f 6f 00 |............foo.| ... Guess I need to think about this some more. -Eric _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
