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2.2.13.4 Procedure for de-allocating metadata blocks.
Set (to one) the bit(s) in the Metadata Bitmap file corresponding to the block number(s)
of the data within the Metadata Partition that is being de-allocated.
2.2.13.5 Recommended procedure for extending the Metadata Partition
These changes should be written to the device before the new blocks are allocated for use
by metadata. It would be undesirable for such changes to sit in an implementation’s write
cache for so long that new metadata assigned to the blocks being described by the
changes was written to the media first.
1. Verify that there is enough space in the Metadata File and Metadata Mirror File
Allocation Descriptor chains for a new Allocation Descriptor. If not then allocate
a new Allocation Descriptor extent.
2. Verify that the Metadata Bitmap file allocation is large enough to extend the
bitmap to describe the additional blocks added to the Metadata File, and if not
then allocate block(s) for the Metadata Bitmap file.
3. Allocate a new extent of blocks (for the Metadata File) observing the size and
alignment requirements specified in2.2.13.1.
4. If the Duplicate Metadata Flag in the Metadata Partition Map Flags field is set,
allocate a second extent of blocks observing the size and alignment requirements
specified in2.2.13.1, ideally as far away as possible from the first allocation (for
the Metadata Mirror File).
5. Add a new Allocation Descriptor to the Metadata File, or modify existing
descriptors, to reference the first newly allocated extent. If the Duplicate
Metadata Flag in the Metadata Partition Map Flags field is not set, modify the
Metadata Mirror file ADs to reference the same extent.
6. If a second extent of blocks was allocated above, add to the Metadata Mirror File
a new Allocation Descriptor, or modify existing ADs, to reference this second
extent.
7. If the new extents were added at the end of the Metadata File then increase the FE
Information Length for the Metadata File, and Mirror, to include the new blocks.
8. If the Metadata Bitmap file was extended, increase its FE Information Length
field to include the bits describing the additional blocks allocated to the Metadata
files.
9. Set (set to one) the bits in the Metadata Bitmap file which correspond to the extent
just added to the Metadata file, to indicate the blocks are available for use by new
metadata.
UDF 2.01
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