This version of the patch is for the 2.4.17
kernel.
Deadlock correction between compressing cluster
and sync of pages.
Management of MAPPED and DIRTY buffer flags.
Test of block numbers in compression.
Test if page is dirty to allocate buffer when
compressing.
When decompressing cluster use the size of
the cluster and not the size of the file, because it can be called from
vmtruncate (the size of the file has already changed).
Management of working area lock.
When (de)compressing file containing holes,
the data must be moved and not only the block number.
New function ext2_decompress_pages() to allocate
blocks for a cluster already read (block decompressed). It is now called
in ext2_decompress_cluster() and not only in ext2_file_write().