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Message-ID: <4D00726D.3080503@lougher.demon.co.uk>
Date: Thu, 09 Dec 2010 06:08:45 +0000
From: Phillip Lougher <phillip@...gher.demon.co.uk>
To: Linux Kernel Development <linux-kernel@...r.kernel.org>,
linux-fsdevel@...r.kernel.org,
Linux Embedded Maillist <linux-embedded@...r.kernel.org>
CC: Lasse Collin <lasse.collin@...aani.org>
Subject: [PATCH 1/2] Squashfs: add XZ compression support
Add XZ decompressor wrapper code.
Signed-off-by: Phillip Lougher <phillip@...gher.demon.co.uk>
---
fs/squashfs/squashfs_fs.h | 1 +
fs/squashfs/xz_wrapper.c | 153 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 154 insertions(+), 0 deletions(-)
create mode 100644 fs/squashfs/xz_wrapper.c
diff --git a/fs/squashfs/squashfs_fs.h b/fs/squashfs/squashfs_fs.h
index c5137fc..39533fe 100644
--- a/fs/squashfs/squashfs_fs.h
+++ b/fs/squashfs/squashfs_fs.h
@@ -238,6 +238,7 @@ struct meta_index {
#define ZLIB_COMPRESSION 1
#define LZMA_COMPRESSION 2
#define LZO_COMPRESSION 3
+#define XZ_COMPRESSION 4
struct squashfs_super_block {
__le32 s_magic;
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c
new file mode 100644
index 0000000..053fe35
--- /dev/null
+++ b/fs/squashfs/xz_wrapper.c
@@ -0,0 +1,153 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ * Phillip Lougher <phillip@...gher.demon.co.uk>
+ *
+ * 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.
+ *
+ * xz_wrapper.c
+ */
+
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/xz.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+struct squashfs_xz {
+ struct xz_dec *state;
+ struct xz_buf buf;
+};
+
+static void *squashfs_xz_init(struct squashfs_sb_info *msblk)
+{
+ int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
+
+ struct squashfs_xz *stream = kmalloc(sizeof(*stream), GFP_KERNEL);
+ if (stream == NULL)
+ goto failed;
+ stream->state = xz_dec_init(XZ_PREALLOC, block_size);
+ if (stream->state == NULL)
+ goto failed;
+
+ return stream;
+
+failed:
+ ERROR("Failed to allocate xz workspace\n");
+ kfree(stream);
+ return NULL;
+}
+
+
+static void squashfs_xz_free(void *strm)
+{
+ struct squashfs_xz *stream = strm;
+
+ if (stream) {
+ xz_dec_end(stream->state);
+ kfree(stream);
+ }
+}
+
+
+static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer,
+ struct buffer_head **bh, int b, int offset, int length, int srclength,
+ int pages)
+{
+ enum xz_ret xz_err;
+ int avail, total = 0, k = 0, page = 0;
+ struct squashfs_xz *stream = msblk->stream;
+
+ mutex_lock(&msblk->read_data_mutex);
+
+ xz_dec_reset(stream->state);
+ stream->buf.in_pos = 0;
+ stream->buf.in_size = 0;
+ stream->buf.out_pos = 0;
+ stream->buf.out_size = PAGE_CACHE_SIZE;
+ stream->buf.out = buffer[page++];
+
+ do {
+ if (stream->buf.in_pos == stream->buf.in_size && k < b) {
+ avail = min(length, msblk->devblksize - offset);
+ length -= avail;
+ wait_on_buffer(bh[k]);
+ if (!buffer_uptodate(bh[k]))
+ goto release_mutex;
+
+ if (avail == 0) {
+ offset = 0;
+ put_bh(bh[k++]);
+ continue;
+ }
+
+ stream->buf.in = bh[k]->b_data + offset;
+ stream->buf.in_size = avail;
+ stream->buf.in_pos = 0;
+ offset = 0;
+ }
+
+ if (stream->buf.out_pos == stream->buf.out_size
+ && page < pages) {
+ stream->buf.out = buffer[page++];
+ stream->buf.out_pos = 0;
+ total += PAGE_CACHE_SIZE;
+ }
+
+ xz_err = xz_dec_run(stream->state, &stream->buf);
+
+ if (stream->buf.in_pos == stream->buf.in_size && k < b)
+ put_bh(bh[k++]);
+ } while (xz_err == XZ_OK);
+
+ if (xz_err != XZ_STREAM_END) {
+ ERROR("xz_dec_run error, data probably corrupt\n");
+ goto release_mutex;
+ }
+
+ if (k < b) {
+ ERROR("xz_uncompress error, input remaining\n");
+ goto release_mutex;
+ }
+
+ total += stream->buf.out_pos;
+ mutex_unlock(&msblk->read_data_mutex);
+ return total;
+
+release_mutex:
+ mutex_unlock(&msblk->read_data_mutex);
+
+ for (; k < b; k++)
+ put_bh(bh[k]);
+
+ return -EIO;
+}
+
+const struct squashfs_decompressor squashfs_xz_comp_ops = {
+ .init = squashfs_xz_init,
+ .free = squashfs_xz_free,
+ .decompress = squashfs_xz_uncompress,
+ .id = XZ_COMPRESSION,
+ .name = "xz",
+ .supported = 1
+};
+
--
1.6.3.3
--
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