Module: UnionFSProbe

Defined in:
lib/fs/MiqFS/modules/UnionFSProbe.rb

Constant Summary collapse

UNIONFS_SUPER_OFFSET = 
1024
UNIONFS_MAGIC_OFFSET = 
52
UNIONFS_MAGIC_SIZE = 
4
UNIONFS_MAGIC = 
0xf15f083d

Class Method Summary collapse

Class Method Details

.probe(dobj) ⇒ Object 



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# File 'lib/fs/MiqFS/modules/UnionFSProbe.rb', line 7

def self.probe(dobj)
  return false unless dobj.kind_of?(MiqDisk)

  # Assume UnionFS - read magic at offset.
  dobj.seek(UNIONFS_SUPER_OFFSET + UNIONFS_MAGIC_OFFSET)
  magic = dobj.read(UNIONFS_MAGIC_SIZE)&.unpack('L')
  raise "UnionFS is Not Supported" if magic == UNIONFS_MAGIC

  # No UnionFS.
  false
end