hammer mirror-copy from old hammer version to new hammer version screws up completely

Matthew Dillon dillon at apollo.backplane.com
Fri Oct 2 09:17:20 PDT 2009


:
:Matthew Dillon wrote:
:> :
:> :When performing a mirror-copy from an old hammer version to a new 
:> :version, no directory contents appear.  the pfs is basically unusable, 
:> :yet uses up disk space.
:> :
:> :THIS IS EXTREMELY ANNOYING AND DANGEROUS.  WHY IS THIS STILL NOT FIXED?
:> :
:> :This is a great opportunity to completely destroy all your data.  EXCELLENT!
:> 
:>     Well, this is the first time I've heard of this.  A mirror-copy
:>     from an old hammer to a new one should work fine in theory.  Are you
:>     sure you weren't copying the other way around?  Copying a new hammer
:>     to an old hammer would not work.
:
:It was certainly from old to new.  This happened before and I reported 
:on IRC, but considered it as an error on my part.  Now it happening 
:again means that something is really wrong.
:
:>     Was it a clean mirror-copy or did you forcefully downgrade a master
:>     into a slave first?
:
:Clean hammer mirror-copy /path/to/old-pfs /path/to/nonexisting-new-pfs
:
:cheers
:   simon

    Ok, it is definitely a bug.  The HAMMER code is creating a root inode
    for the slave PFS, which causes it to ignore the root inode it would
    otherwise copy from the master.  This combined with the directory
    capabilities being different between version 1 and version 2 is
    breaking the root directory.

    I have committed fixes to both master and DragonFly_RELEASE_2_4.
    Any newly created slave PFSs should work as expect when doing a
    mirror-copy from an older HAMMER filesystem to a newer one.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>





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