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-rw-r--r--src/zstd/contrib/linux-kernel/0004-squashfs-Add-zstd-support.patch306
1 files changed, 306 insertions, 0 deletions
diff --git a/src/zstd/contrib/linux-kernel/0004-squashfs-Add-zstd-support.patch b/src/zstd/contrib/linux-kernel/0004-squashfs-Add-zstd-support.patch
new file mode 100644
index 000000000..36cdf71df
--- /dev/null
+++ b/src/zstd/contrib/linux-kernel/0004-squashfs-Add-zstd-support.patch
@@ -0,0 +1,306 @@
+From 46bf8f6d30d6ddf2446c110f122482b5e5e16933 Mon Sep 17 00:00:00 2001
+From: Sean Purcell <me@seanp.xyz>
+Date: Mon, 17 Jul 2017 17:08:59 -0700
+Subject: [PATCH v5 4/5] squashfs: Add zstd support
+
+Add zstd compression and decompression support to SquashFS. zstd is a
+great fit for SquashFS because it can compress at ratios approaching xz,
+while decompressing twice as fast as zlib. For SquashFS in particular,
+it can decompress as fast as lzo and lz4. It also has the flexibility
+to turn down the compression ratio for faster compression times.
+
+The compression benchmark is run on the file tree from the SquashFS archive
+found in ubuntu-16.10-desktop-amd64.iso [1]. It uses `mksquashfs` with the
+default block size (128 KB) and and various compression algorithms/levels.
+xz and zstd are also benchmarked with 256 KB blocks. The decompression
+benchmark times how long it takes to `tar` the file tree into `/dev/null`.
+See the benchmark file in the upstream zstd source repository located under
+`contrib/linux-kernel/squashfs-benchmark.sh` [2] for details.
+
+I ran the benchmarks on a Ubuntu 14.04 VM with 2 cores and 4 GiB of RAM.
+The VM is running on a MacBook Pro with a 3.1 GHz Intel Core i7 processor,
+16 GB of RAM, and a SSD.
+
+| Method | Ratio | Compression MB/s | Decompression MB/s |
+|----------------|-------|------------------|--------------------|
+| gzip | 2.92 | 15 | 128 |
+| lzo | 2.64 | 9.5 | 217 |
+| lz4 | 2.12 | 94 | 218 |
+| xz | 3.43 | 5.5 | 35 |
+| xz 256 KB | 3.53 | 5.4 | 40 |
+| zstd 1 | 2.71 | 96 | 210 |
+| zstd 5 | 2.93 | 69 | 198 |
+| zstd 10 | 3.01 | 41 | 225 |
+| zstd 15 | 3.13 | 11.4 | 224 |
+| zstd 16 256 KB | 3.24 | 8.1 | 210 |
+
+This patch was written by Sean Purcell <me@seanp.xyz>, but I will be
+taking over the submission process.
+
+[1] http://releases.ubuntu.com/16.10/
+[2] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/squashfs-benchmark.sh
+
+zstd source repository: https://github.com/facebook/zstd
+
+Signed-off-by: Sean Purcell <me@seanp.xyz>
+Signed-off-by: Nick Terrell <terrelln@fb.com>
+---
+v3 -> v4:
+- Fix minor linter warnings
+
+v4 -> v5:
+- Fix ZSTD_DStream initialization code in squashfs
+- Fix patch documentation to reflect that Sean Purcell is the author
+
+ fs/squashfs/Kconfig | 14 +++++
+ fs/squashfs/Makefile | 1 +
+ fs/squashfs/decompressor.c | 7 +++
+ fs/squashfs/decompressor.h | 4 ++
+ fs/squashfs/squashfs_fs.h | 1 +
+ fs/squashfs/zstd_wrapper.c | 151 +++++++++++++++++++++++++++++++++++++++++++++
+ 6 files changed, 178 insertions(+)
+ create mode 100644 fs/squashfs/zstd_wrapper.c
+
+diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
+index ffb093e..1adb334 100644
+--- a/fs/squashfs/Kconfig
++++ b/fs/squashfs/Kconfig
+@@ -165,6 +165,20 @@ config SQUASHFS_XZ
+
+ If unsure, say N.
+
++config SQUASHFS_ZSTD
++ bool "Include support for ZSTD compressed file systems"
++ depends on SQUASHFS
++ select ZSTD_DECOMPRESS
++ help
++ Saying Y here includes support for reading Squashfs file systems
++ compressed with ZSTD compression. ZSTD gives better compression than
++ the default ZLIB compression, while using less CPU.
++
++ ZSTD is not the standard compression used in Squashfs and so most
++ file systems will be readable without selecting this option.
++
++ If unsure, say N.
++
+ config SQUASHFS_4K_DEVBLK_SIZE
+ bool "Use 4K device block size?"
+ depends on SQUASHFS
+diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
+index 246a6f3..6655631 100644
+--- a/fs/squashfs/Makefile
++++ b/fs/squashfs/Makefile
+@@ -15,3 +15,4 @@ squashfs-$(CONFIG_SQUASHFS_LZ4) += lz4_wrapper.o
+ squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
+ squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
+ squashfs-$(CONFIG_SQUASHFS_ZLIB) += zlib_wrapper.o
++squashfs-$(CONFIG_SQUASHFS_ZSTD) += zstd_wrapper.o
+diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
+index d2bc136..8366398 100644
+--- a/fs/squashfs/decompressor.c
++++ b/fs/squashfs/decompressor.c
+@@ -65,6 +65,12 @@ static const struct squashfs_decompressor squashfs_zlib_comp_ops = {
+ };
+ #endif
+
++#ifndef CONFIG_SQUASHFS_ZSTD
++static const struct squashfs_decompressor squashfs_zstd_comp_ops = {
++ NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 0
++};
++#endif
++
+ static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
+ NULL, NULL, NULL, NULL, 0, "unknown", 0
+ };
+@@ -75,6 +81,7 @@ static const struct squashfs_decompressor *decompressor[] = {
+ &squashfs_lzo_comp_ops,
+ &squashfs_xz_comp_ops,
+ &squashfs_lzma_unsupported_comp_ops,
++ &squashfs_zstd_comp_ops,
+ &squashfs_unknown_comp_ops
+ };
+
+diff --git a/fs/squashfs/decompressor.h b/fs/squashfs/decompressor.h
+index a25713c..0f5a8e4 100644
+--- a/fs/squashfs/decompressor.h
++++ b/fs/squashfs/decompressor.h
+@@ -58,4 +58,8 @@ extern const struct squashfs_decompressor squashfs_lzo_comp_ops;
+ extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
+ #endif
+
++#ifdef CONFIG_SQUASHFS_ZSTD
++extern const struct squashfs_decompressor squashfs_zstd_comp_ops;
++#endif
++
+ #endif
+diff --git a/fs/squashfs/squashfs_fs.h b/fs/squashfs/squashfs_fs.h
+index 506f4ba..24d12fd 100644
+--- a/fs/squashfs/squashfs_fs.h
++++ b/fs/squashfs/squashfs_fs.h
+@@ -241,6 +241,7 @@ struct meta_index {
+ #define LZO_COMPRESSION 3
+ #define XZ_COMPRESSION 4
+ #define LZ4_COMPRESSION 5
++#define ZSTD_COMPRESSION 6
+
+ struct squashfs_super_block {
+ __le32 s_magic;
+diff --git a/fs/squashfs/zstd_wrapper.c b/fs/squashfs/zstd_wrapper.c
+new file mode 100644
+index 0000000..eeaabf8
+--- /dev/null
++++ b/fs/squashfs/zstd_wrapper.c
+@@ -0,0 +1,151 @@
++/*
++ * Squashfs - a compressed read only filesystem for Linux
++ *
++ * Copyright (c) 2016-present, Facebook, Inc.
++ * All rights reserved.
++ *
++ * This program is free software; you can redistribute it and/or
++ * modify it under the terms of the GNU General Public License
++ * as published by the Free Software Foundation; either version 2,
++ * or (at your option) any later version.
++ *
++ * This program is distributed in the hope that it will be useful,
++ * but WITHOUT ANY WARRANTY; without even the implied warranty of
++ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
++ * GNU General Public License for more details.
++ *
++ * zstd_wrapper.c
++ */
++
++#include <linux/mutex.h>
++#include <linux/buffer_head.h>
++#include <linux/slab.h>
++#include <linux/zstd.h>
++#include <linux/vmalloc.h>
++
++#include "squashfs_fs.h"
++#include "squashfs_fs_sb.h"
++#include "squashfs.h"
++#include "decompressor.h"
++#include "page_actor.h"
++
++struct workspace {
++ void *mem;
++ size_t mem_size;
++ size_t window_size;
++};
++
++static void *zstd_init(struct squashfs_sb_info *msblk, void *buff)
++{
++ struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL);
++
++ if (wksp == NULL)
++ goto failed;
++ wksp->window_size = max_t(size_t,
++ msblk->block_size, SQUASHFS_METADATA_SIZE);
++ wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size);
++ wksp->mem = vmalloc(wksp->mem_size);
++ if (wksp->mem == NULL)
++ goto failed;
++
++ return wksp;
++
++failed:
++ ERROR("Failed to allocate zstd workspace\n");
++ kfree(wksp);
++ return ERR_PTR(-ENOMEM);
++}
++
++
++static void zstd_free(void *strm)
++{
++ struct workspace *wksp = strm;
++
++ if (wksp)
++ vfree(wksp->mem);
++ kfree(wksp);
++}
++
++
++static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
++ struct buffer_head **bh, int b, int offset, int length,
++ struct squashfs_page_actor *output)
++{
++ struct workspace *wksp = strm;
++ ZSTD_DStream *stream;
++ size_t total_out = 0;
++ size_t zstd_err;
++ int k = 0;
++ ZSTD_inBuffer in_buf = { NULL, 0, 0 };
++ ZSTD_outBuffer out_buf = { NULL, 0, 0 };
++
++ stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size);
++
++ if (!stream) {
++ ERROR("Failed to initialize zstd decompressor\n");
++ goto out;
++ }
++
++ out_buf.size = PAGE_SIZE;
++ out_buf.dst = squashfs_first_page(output);
++
++ do {
++ if (in_buf.pos == in_buf.size && k < b) {
++ int avail = min(length, msblk->devblksize - offset);
++
++ length -= avail;
++ in_buf.src = bh[k]->b_data + offset;
++ in_buf.size = avail;
++ in_buf.pos = 0;
++ offset = 0;
++ }
++
++ if (out_buf.pos == out_buf.size) {
++ out_buf.dst = squashfs_next_page(output);
++ if (out_buf.dst == NULL) {
++ /* Shouldn't run out of pages
++ * before stream is done.
++ */
++ squashfs_finish_page(output);
++ goto out;
++ }
++ out_buf.pos = 0;
++ out_buf.size = PAGE_SIZE;
++ }
++
++ total_out -= out_buf.pos;
++ zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf);
++ total_out += out_buf.pos; /* add the additional data produced */
++
++ if (in_buf.pos == in_buf.size && k < b)
++ put_bh(bh[k++]);
++ } while (zstd_err != 0 && !ZSTD_isError(zstd_err));
++
++ squashfs_finish_page(output);
++
++ if (ZSTD_isError(zstd_err)) {
++ ERROR("zstd decompression error: %d\n",
++ (int)ZSTD_getErrorCode(zstd_err));
++ goto out;
++ }
++
++ if (k < b)
++ goto out;
++
++ return (int)total_out;
++
++out:
++ for (; k < b; k++)
++ put_bh(bh[k]);
++
++ return -EIO;
++}
++
++const struct squashfs_decompressor squashfs_zstd_comp_ops = {
++ .init = zstd_init,
++ .free = zstd_free,
++ .decompress = zstd_uncompress,
++ .id = ZSTD_COMPRESSION,
++ .name = "zstd",
++ .supported = 1
++};
+--
+2.9.3
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