2 * Squashfs - a compressed read only filesystem for Linux
4 * Copyright (c) 2016-present, Facebook, Inc.
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2,
10 * or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
20 #include <linux/mutex.h>
21 #include <linux/buffer_head.h>
22 #include <linux/slab.h>
23 #include <linux/zstd.h>
24 #include <linux/vmalloc.h>
26 #include "squashfs_fs.h"
27 #include "squashfs_fs_sb.h"
29 #include "decompressor.h"
30 #include "page_actor.h"
38 static void *zstd_init(struct squashfs_sb_info *msblk, void *buff)
40 struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL);
44 wksp->window_size = max_t(size_t,
45 msblk->block_size, SQUASHFS_METADATA_SIZE);
46 wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size);
47 wksp->mem = vmalloc(wksp->mem_size);
48 if (wksp->mem == NULL)
54 ERROR("Failed to allocate zstd workspace\n");
56 return ERR_PTR(-ENOMEM);
60 static void zstd_free(void *strm)
62 struct workspace *wksp = strm;
70 static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
71 struct buffer_head **bh, int b, int offset, int length,
72 struct squashfs_page_actor *output)
74 struct workspace *wksp = strm;
79 ZSTD_inBuffer in_buf = { NULL, 0, 0 };
80 ZSTD_outBuffer out_buf = { NULL, 0, 0 };
82 stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size);
85 ERROR("Failed to initialize zstd decompressor\n");
89 out_buf.size = PAGE_SIZE;
90 out_buf.dst = squashfs_first_page(output);
93 if (in_buf.pos == in_buf.size && k < b) {
94 int avail = min(length, msblk->devblksize - offset);
97 in_buf.src = bh[k]->b_data + offset;
103 if (out_buf.pos == out_buf.size) {
104 out_buf.dst = squashfs_next_page(output);
105 if (out_buf.dst == NULL) {
106 /* Shouldn't run out of pages
107 * before stream is done.
109 squashfs_finish_page(output);
113 out_buf.size = PAGE_SIZE;
116 total_out -= out_buf.pos;
117 zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf);
118 total_out += out_buf.pos; /* add the additional data produced */
120 if (in_buf.pos == in_buf.size && k < b)
122 } while (zstd_err != 0 && !ZSTD_isError(zstd_err));
124 squashfs_finish_page(output);
126 if (ZSTD_isError(zstd_err)) {
127 ERROR("zstd decompression error: %d\n",
128 (int)ZSTD_getErrorCode(zstd_err));
135 return (int)total_out;
144 const struct squashfs_decompressor squashfs_zstd_comp_ops = {
147 .decompress = zstd_uncompress,
148 .id = ZSTD_COMPRESSION,