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d23142c627
Currently punch hole is disabled in file systems with bigalloc feature enabled. However the recent changes in punch hole patch should make it easier to support punching holes on bigalloc enabled file systems. This commit changes partial_cluster handling in ext4_remove_blocks(), ext4_ext_rm_leaf() and ext4_ext_remove_space(). Currently partial_cluster is unsigned long long type and it makes sure that we will free the partial cluster if all extents has been released from that cluster. However it has been specifically designed only for truncate. With punch hole we can be freeing just some extents in the cluster leaving the rest untouched. So we have to make sure that we will notice cluster which still has some extents. To do this I've changed partial_cluster to be signed long long type. The only scenario where this could be a problem is when cluster_size == block size, however in that case there would not be any partial clusters so we're safe. For bigger clusters the signed type is enough. Now we use the negative value in partial_cluster to mark such cluster used, hence we know that we must not free it even if all other extents has been freed from such cluster. This scenario can be described in simple diagram: |FFF...FF..FF.UUU| ^----------^ punch hole . - free space | - cluster boundary F - freed extent U - used extent Also update respective tracepoints to use signed long long type for partial_cluster. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
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