btrfs: Allow to add new compression algorithm

Make the code aware of compression type, instead of always assuming
zlib compression.

Also make the zlib workspace function as common code for all
compression types.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 66836d85763b..05df688c96f4 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -224,6 +224,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 
                         split->bdev = em->bdev;
                         split->flags = flags;
+                        split->compress_type = em->compress_type;
                         ret = add_extent_mapping(em_tree, split);
                         BUG_ON(ret);
                         free_extent_map(split);
@@ -238,6 +239,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                         split->len = em->start + em->len - (start + len);
                         split->bdev = em->bdev;
                         split->flags = flags;
+                        split->compress_type = em->compress_type;
 
                         if (compressed) {
                                 split->block_len = em->block_len;