Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755387Ab3GVC3R (ORCPT ); Sun, 21 Jul 2013 22:29:17 -0400 Received: from mdfmta010.mxout.tbr.inty.net ([91.221.168.51]:56982 "EHLO smtp.demon.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754602Ab3GVC3P (ORCPT ); Sun, 21 Jul 2013 22:29:15 -0400 From: Phillip Lougher To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-embedded@vger.kernel.org Cc: Phillip Lougher Subject: [PATCH 1/2] Squashfs: add LZ4 compression support Date: Mon, 22 Jul 2013 03:21:02 +0100 Message-Id: <1374459663-15363-2-git-send-email-phillip@squashfs.org.uk> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1374459663-15363-1-git-send-email-phillip@squashfs.org.uk> References: <1374459663-15363-1-git-send-email-phillip@squashfs.org.uk> X-MDF-HostID: 3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5140 Lines: 201 Add support for reading file systems compressed with the LZ4 compression algorithm. This patch adds the LZ4 decompressor wrapper code. Signed-off-by: Phillip Lougher --- fs/squashfs/lz4_wrapper.c | 163 +++++++++++++++++++++++++++++++++++++++++++++ fs/squashfs/squashfs_fs.h | 1 + 2 files changed, 164 insertions(+) create mode 100644 fs/squashfs/lz4_wrapper.c diff --git a/fs/squashfs/lz4_wrapper.c b/fs/squashfs/lz4_wrapper.c new file mode 100644 index 0000000..681ed94 --- /dev/null +++ b/fs/squashfs/lz4_wrapper.c @@ -0,0 +1,163 @@ +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2013 + * Phillip Lougher + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * lz4_wrapper.c + */ + +#include +#include +#include +#include +#include + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "squashfs.h" +#include "decompressor.h" + +#define LZ4_LEGACY 1 + +struct lz4_comp_opts { + __le32 version; + __le32 flags; +}; + +struct squashfs_lz4 { + void *input; + void *output; +}; + + + +static void *lz4_init(struct squashfs_sb_info *msblk, void *buff, int len) +{ + struct lz4_comp_opts *comp_opts = buff; + int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE); + struct squashfs_lz4 *stream; + int err = -ENOMEM; + + /* LZ4 compressed filesystems always have compression options */ + if(comp_opts == NULL || len < sizeof(*comp_opts)) { + err = -EIO; + goto failed; + } + if(le32_to_cpu(comp_opts->version) != LZ4_LEGACY) { + /* LZ4 format currently used by the kernel is the 'legacy' + * format */ + ERROR("Unknown LZ4 version\n"); + err = -EINVAL; + goto failed; + } + + stream = kzalloc(sizeof(*stream), GFP_KERNEL); + if (stream == NULL) + goto failed; + stream->input = vmalloc(block_size); + if (stream->input == NULL) + goto failed2; + stream->output = vmalloc(block_size); + if (stream->output == NULL) + goto failed3; + + return stream; + +failed3: + vfree(stream->input); +failed2: + kfree(stream); +failed: + ERROR("Failed to initialise LZ4 decompressor\n"); + return ERR_PTR(err); +} + + +static void lz4_free(void *strm) +{ + struct squashfs_lz4 *stream = strm; + + if (stream) { + vfree(stream->input); + vfree(stream->output); + } + kfree(stream); +} + + +static int lz4_uncompress(struct squashfs_sb_info *msblk, void **buffer, + struct buffer_head **bh, int b, int offset, int length, int srclength, + int pages) +{ + struct squashfs_lz4 *stream = msblk->stream; + void *buff = stream->input; + int avail, i, bytes = length, res; + size_t dest_len = srclength; + + mutex_lock(&msblk->read_data_mutex); + + for (i = 0; i < b; i++) { + wait_on_buffer(bh[i]); + if (!buffer_uptodate(bh[i])) + goto block_release; + + avail = min(bytes, msblk->devblksize - offset); + memcpy(buff, bh[i]->b_data + offset, avail); + buff += avail; + bytes -= avail; + offset = 0; + put_bh(bh[i]); + } + + res = lz4_decompress_unknownoutputsize(stream->input, length, + stream->output, &dest_len); + if (res) + goto failed; + + bytes = dest_len; + for (i = 0, buff = stream->output; bytes && i < pages; i++) { + avail = min_t(int, bytes, PAGE_CACHE_SIZE); + memcpy(buffer[i], buff, avail); + buff += avail; + bytes -= avail; + } + if (bytes) + goto failed; + + mutex_unlock(&msblk->read_data_mutex); + return dest_len; + +block_release: + for (; i < b; i++) + put_bh(bh[i]); + +failed: + mutex_unlock(&msblk->read_data_mutex); + + ERROR("lz4 decompression failed, data probably corrupt\n"); + return -EIO; +} + +const struct squashfs_decompressor squashfs_lz4_comp_ops = { + .init = lz4_init, + .free = lz4_free, + .decompress = lz4_uncompress, + .id = LZ4_COMPRESSION, + .name = "lz4", + .supported = 1 +}; diff --git a/fs/squashfs/squashfs_fs.h b/fs/squashfs/squashfs_fs.h index 9e2349d..ee0be5c 100644 --- a/fs/squashfs/squashfs_fs.h +++ b/fs/squashfs/squashfs_fs.h @@ -237,6 +237,7 @@ struct meta_index { #define LZMA_COMPRESSION 2 #define LZO_COMPRESSION 3 #define XZ_COMPRESSION 4 +#define LZ4_COMPRESSION 5 struct squashfs_super_block { __le32 s_magic; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/