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, 4 insertions, 1 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 5e7a94d7da89..f1d198128959 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2028,8 +2028,11 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
                 BUG_ON(extent_map_end(em) <= cur);
                 BUG_ON(end < cur);
 
-                if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
+                if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
                         this_bio_flag = EXTENT_BIO_COMPRESSED;
+                        extent_set_compress_type(&this_bio_flag,
+                                                 em->compress_type);
+                }
 
                 iosize = min(extent_map_end(em) - cur, end - cur + 1);
                 cur_end = min(extent_map_end(em) - 1, end);