[v2,3/4] btrfs: Add zstd support

Commit Message

Adam Borowski June 30, 2017, 3:24 a.m. UTC

On Thu, Jun 29, 2017 at 12:41:07PM -0700, Nick Terrell wrote:
> Add zstd compression and decompression support to BtrFS. zstd at its
> fastest level compresses almost as well as zlib, while offering much
> faster compression and decompression, approaching lzo speeds.

> +static int zstd_decompress_bio(struct list_head *ws, struct page **pages_in,
> +		u64 disk_start,
> +		struct bio *orig_bio,
> +		size_t srclen)

Note that this fails to build if e1ddce71 is applied, and it'll be in
mainline in just a few days from now.  Fixing that is obvious, but
to avoid duplicating the effort:

Patch

diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
index 838741b3732c..e9403e569d8e 100644
--- a/fs/btrfs/zstd.c
+++ b/fs/btrfs/zstd.c
@@ -25,6 +25,7 @@ 
 #include <linux/pagemap.h>
 #include <linux/bio.h>
 #include <linux/zstd.h>
+#include <linux/refcount.h>
 #include "compression.h"
 
 #define ZSTD_BTRFS_MAX_WINDOWLOG 17
@@ -262,17 +263,18 @@  static int zstd_compress_pages(struct list_head *ws,
        return ret;
 }
 
-static int zstd_decompress_bio(struct list_head *ws, struct page **pages_in,
-               u64 disk_start,
-               struct bio *orig_bio,
-               size_t srclen)
+static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 {
        struct workspace *workspace = list_entry(ws, struct workspace, list);
        ZSTD_DStream *stream;
        int ret = 0;
        unsigned long page_in_index = 0;
+       size_t srclen = cb->compressed_len;
        unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
        unsigned long buf_start;
+       struct page **pages_in = cb->compressed_pages;
+       u64 disk_start = cb->start;
+       struct bio *orig_bio = cb->orig_bio;
        unsigned long total_out = 0;
        ZSTD_inBuffer in_buf = { NULL, 0, 0 };
        ZSTD_outBuffer out_buf = { NULL, 0, 0 };