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-rw-r--r--fs/btrfs/zlib.c412
1 files changed, 412 insertions, 0 deletions
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
new file mode 100644
index 000000000..82990b8f8
--- /dev/null
+++ b/fs/btrfs/zlib.c
@@ -0,0 +1,412 @@
+/*
+ * Copyright (C) 2008 Oracle. 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 v2 as published by the Free Software Foundation.
+ *
+ * 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, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ *
+ * Based on jffs2 zlib code:
+ * Copyright © 2001-2007 Red Hat, Inc.
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/zlib.h>
+#include <linux/zutil.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include "compression.h"
+
+struct workspace {
+ z_stream strm;
+ char *buf;
+ struct list_head list;
+};
+
+static void zlib_free_workspace(struct list_head *ws)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+
+ vfree(workspace->strm.workspace);
+ kfree(workspace->buf);
+ kfree(workspace);
+}
+
+static struct list_head *zlib_alloc_workspace(void)
+{
+ struct workspace *workspace;
+ int workspacesize;
+
+ workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
+ if (!workspace)
+ return ERR_PTR(-ENOMEM);
+
+ workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
+ zlib_inflate_workspacesize());
+ workspace->strm.workspace = vmalloc(workspacesize);
+ workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
+ if (!workspace->strm.workspace || !workspace->buf)
+ goto fail;
+
+ INIT_LIST_HEAD(&workspace->list);
+
+ return &workspace->list;
+fail:
+ zlib_free_workspace(&workspace->list);
+ return ERR_PTR(-ENOMEM);
+}
+
+static int zlib_compress_pages(struct list_head *ws,
+ struct address_space *mapping,
+ u64 start, unsigned long len,
+ struct page **pages,
+ unsigned long nr_dest_pages,
+ unsigned long *out_pages,
+ unsigned long *total_in,
+ unsigned long *total_out,
+ unsigned long max_out)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ int ret;
+ char *data_in;
+ char *cpage_out;
+ int nr_pages = 0;
+ struct page *in_page = NULL;
+ struct page *out_page = NULL;
+ unsigned long bytes_left;
+
+ *out_pages = 0;
+ *total_out = 0;
+ *total_in = 0;
+
+ if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) {
+ printk(KERN_WARNING "BTRFS: deflateInit failed\n");
+ ret = -EIO;
+ goto out;
+ }
+
+ workspace->strm.total_in = 0;
+ workspace->strm.total_out = 0;
+
+ in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
+ data_in = kmap(in_page);
+
+ out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_page == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ cpage_out = kmap(out_page);
+ pages[0] = out_page;
+ nr_pages = 1;
+
+ workspace->strm.next_in = data_in;
+ workspace->strm.next_out = cpage_out;
+ workspace->strm.avail_out = PAGE_CACHE_SIZE;
+ workspace->strm.avail_in = min(len, PAGE_CACHE_SIZE);
+
+ while (workspace->strm.total_in < len) {
+ ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
+ if (ret != Z_OK) {
+ printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n",
+ ret);
+ zlib_deflateEnd(&workspace->strm);
+ ret = -EIO;
+ goto out;
+ }
+
+ /* we're making it bigger, give up */
+ if (workspace->strm.total_in > 8192 &&
+ workspace->strm.total_in <
+ workspace->strm.total_out) {
+ ret = -E2BIG;
+ goto out;
+ }
+ /* we need another page for writing out. Test this
+ * before the total_in so we will pull in a new page for
+ * the stream end if required
+ */
+ if (workspace->strm.avail_out == 0) {
+ kunmap(out_page);
+ if (nr_pages == nr_dest_pages) {
+ out_page = NULL;
+ ret = -E2BIG;
+ goto out;
+ }
+ out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_page == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ cpage_out = kmap(out_page);
+ pages[nr_pages] = out_page;
+ nr_pages++;
+ workspace->strm.avail_out = PAGE_CACHE_SIZE;
+ workspace->strm.next_out = cpage_out;
+ }
+ /* we're all done */
+ if (workspace->strm.total_in >= len)
+ break;
+
+ /* we've read in a full page, get a new one */
+ if (workspace->strm.avail_in == 0) {
+ if (workspace->strm.total_out > max_out)
+ break;
+
+ bytes_left = len - workspace->strm.total_in;
+ kunmap(in_page);
+ page_cache_release(in_page);
+
+ start += PAGE_CACHE_SIZE;
+ in_page = find_get_page(mapping,
+ start >> PAGE_CACHE_SHIFT);
+ data_in = kmap(in_page);
+ workspace->strm.avail_in = min(bytes_left,
+ PAGE_CACHE_SIZE);
+ workspace->strm.next_in = data_in;
+ }
+ }
+ workspace->strm.avail_in = 0;
+ ret = zlib_deflate(&workspace->strm, Z_FINISH);
+ zlib_deflateEnd(&workspace->strm);
+
+ if (ret != Z_STREAM_END) {
+ ret = -EIO;
+ goto out;
+ }
+
+ if (workspace->strm.total_out >= workspace->strm.total_in) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ ret = 0;
+ *total_out = workspace->strm.total_out;
+ *total_in = workspace->strm.total_in;
+out:
+ *out_pages = nr_pages;
+ if (out_page)
+ kunmap(out_page);
+
+ if (in_page) {
+ kunmap(in_page);
+ page_cache_release(in_page);
+ }
+ return ret;
+}
+
+static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
+ u64 disk_start,
+ struct bio_vec *bvec,
+ int vcnt,
+ size_t srclen)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ int ret = 0, ret2;
+ int wbits = MAX_WBITS;
+ char *data_in;
+ size_t total_out = 0;
+ unsigned long page_in_index = 0;
+ unsigned long page_out_index = 0;
+ unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_CACHE_SIZE);
+ unsigned long buf_start;
+ unsigned long pg_offset;
+
+ data_in = kmap(pages_in[page_in_index]);
+ workspace->strm.next_in = data_in;
+ workspace->strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
+ workspace->strm.total_in = 0;
+
+ workspace->strm.total_out = 0;
+ workspace->strm.next_out = workspace->buf;
+ workspace->strm.avail_out = PAGE_CACHE_SIZE;
+ pg_offset = 0;
+
+ /* If it's deflate, and it's got no preset dictionary, then
+ we can tell zlib to skip the adler32 check. */
+ if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
+ ((data_in[0] & 0x0f) == Z_DEFLATED) &&
+ !(((data_in[0]<<8) + data_in[1]) % 31)) {
+
+ wbits = -((data_in[0] >> 4) + 8);
+ workspace->strm.next_in += 2;
+ workspace->strm.avail_in -= 2;
+ }
+
+ if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
+ printk(KERN_WARNING "BTRFS: inflateInit failed\n");
+ return -EIO;
+ }
+ while (workspace->strm.total_in < srclen) {
+ ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
+ if (ret != Z_OK && ret != Z_STREAM_END)
+ break;
+
+ buf_start = total_out;
+ total_out = workspace->strm.total_out;
+
+ /* we didn't make progress in this inflate call, we're done */
+ if (buf_start == total_out)
+ break;
+
+ ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
+ total_out, disk_start,
+ bvec, vcnt,
+ &page_out_index, &pg_offset);
+ if (ret2 == 0) {
+ ret = 0;
+ goto done;
+ }
+
+ workspace->strm.next_out = workspace->buf;
+ workspace->strm.avail_out = PAGE_CACHE_SIZE;
+
+ if (workspace->strm.avail_in == 0) {
+ unsigned long tmp;
+ kunmap(pages_in[page_in_index]);
+ page_in_index++;
+ if (page_in_index >= total_pages_in) {
+ data_in = NULL;
+ break;
+ }
+ data_in = kmap(pages_in[page_in_index]);
+ workspace->strm.next_in = data_in;
+ tmp = srclen - workspace->strm.total_in;
+ workspace->strm.avail_in = min(tmp,
+ PAGE_CACHE_SIZE);
+ }
+ }
+ if (ret != Z_STREAM_END)
+ ret = -EIO;
+ else
+ ret = 0;
+done:
+ zlib_inflateEnd(&workspace->strm);
+ if (data_in)
+ kunmap(pages_in[page_in_index]);
+ if (!ret)
+ btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset);
+ return ret;
+}
+
+static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
+ struct page *dest_page,
+ unsigned long start_byte,
+ size_t srclen, size_t destlen)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ int ret = 0;
+ int wbits = MAX_WBITS;
+ unsigned long bytes_left;
+ unsigned long total_out = 0;
+ unsigned long pg_offset = 0;
+ char *kaddr;
+
+ destlen = min_t(unsigned long, destlen, PAGE_SIZE);
+ bytes_left = destlen;
+
+ workspace->strm.next_in = data_in;
+ workspace->strm.avail_in = srclen;
+ workspace->strm.total_in = 0;
+
+ workspace->strm.next_out = workspace->buf;
+ workspace->strm.avail_out = PAGE_CACHE_SIZE;
+ workspace->strm.total_out = 0;
+ /* If it's deflate, and it's got no preset dictionary, then
+ we can tell zlib to skip the adler32 check. */
+ if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
+ ((data_in[0] & 0x0f) == Z_DEFLATED) &&
+ !(((data_in[0]<<8) + data_in[1]) % 31)) {
+
+ wbits = -((data_in[0] >> 4) + 8);
+ workspace->strm.next_in += 2;
+ workspace->strm.avail_in -= 2;
+ }
+
+ if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
+ printk(KERN_WARNING "BTRFS: inflateInit failed\n");
+ return -EIO;
+ }
+
+ while (bytes_left > 0) {
+ unsigned long buf_start;
+ unsigned long buf_offset;
+ unsigned long bytes;
+
+ ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
+ if (ret != Z_OK && ret != Z_STREAM_END)
+ break;
+
+ buf_start = total_out;
+ total_out = workspace->strm.total_out;
+
+ if (total_out == buf_start) {
+ ret = -EIO;
+ break;
+ }
+
+ if (total_out <= start_byte)
+ goto next;
+
+ if (total_out > start_byte && buf_start < start_byte)
+ buf_offset = start_byte - buf_start;
+ else
+ buf_offset = 0;
+
+ bytes = min(PAGE_CACHE_SIZE - pg_offset,
+ PAGE_CACHE_SIZE - buf_offset);
+ bytes = min(bytes, bytes_left);
+
+ kaddr = kmap_atomic(dest_page);
+ memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
+ kunmap_atomic(kaddr);
+
+ pg_offset += bytes;
+ bytes_left -= bytes;
+next:
+ workspace->strm.next_out = workspace->buf;
+ workspace->strm.avail_out = PAGE_CACHE_SIZE;
+ }
+
+ if (ret != Z_STREAM_END && bytes_left != 0)
+ ret = -EIO;
+ else
+ ret = 0;
+
+ zlib_inflateEnd(&workspace->strm);
+
+ /*
+ * this should only happen if zlib returned fewer bytes than we
+ * expected. btrfs_get_block is responsible for zeroing from the
+ * end of the inline extent (destlen) to the end of the page
+ */
+ if (pg_offset < destlen) {
+ kaddr = kmap_atomic(dest_page);
+ memset(kaddr + pg_offset, 0, destlen - pg_offset);
+ kunmap_atomic(kaddr);
+ }
+ return ret;
+}
+
+const struct btrfs_compress_op btrfs_zlib_compress = {
+ .alloc_workspace = zlib_alloc_workspace,
+ .free_workspace = zlib_free_workspace,
+ .compress_pages = zlib_compress_pages,
+ .decompress_biovec = zlib_decompress_biovec,
+ .decompress = zlib_decompress,
+};
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