btrfs: introduce btrfs_compress_bio() helper

The helper will allocate a new compressed_bio, do the compression, and
return it to the caller.

This greatly simplifies the compression path, as we no longer need to
allocate a folio array thus no extra error path, furthermore the
compressed bio structure can be utilized for submission with very minor
modifications (like rounding up the bi_size and populate the bi_sector).

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index eee4190efa02..fd0cce5d07cf 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -146,6 +146,19 @@ int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end);
 
 int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
 				     struct folio **in_folio_ret);
+struct compressed_bio *btrfs_compress_bio(struct btrfs_inode *inode,
+					  u64 start, u32 len, unsigned int type,
+					  int level, blk_opf_t write_flags);
+
+static inline void cleanup_compressed_bio(struct compressed_bio *cb)
+{
+	struct bio *bio = &cb->bbio.bio;
+	struct folio_iter fi;
+
+	bio_for_each_folio_all(fi, bio)
+		btrfs_free_compr_folio(fi.folio);
+	bio_put(bio);
+}
 
 int zlib_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
 			 u64 start, struct folio **folios, unsigned long *out_folios,