btrfs: Extract duplicate decompress code

Add a common function to copy decompressed data from working buffer
to bio pages.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index f7ce217113f..51000174b9d 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -34,6 +34,11 @@ int btrfs_decompress_biovec(int type, struct page **pages_in, u64 disk_start,
                             struct bio_vec *bvec, int vcnt, size_t srclen);
 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
                      unsigned long start_byte, size_t srclen, size_t destlen);
+int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
+                              unsigned long total_out, u64 disk_start,
+                              struct bio_vec *bvec, int vcnt,
+                              unsigned long *page_index,
+                              unsigned long *pg_offset);
 
 int btrfs_submit_compressed_write(struct inode *inode, u64 start,
                                   unsigned long len, u64 disk_start,