413 lines
10 KiB
C
413 lines
10 KiB
C
/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*
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* Based on jffs2 zlib code:
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* Copyright © 2001-2007 Red Hat, Inc.
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* Created by David Woodhouse <dwmw2@infradead.org>
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/zlib.h>
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#include <linux/zutil.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <linux/pagemap.h>
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#include <linux/bio.h>
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#include "compression.h"
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struct workspace {
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z_stream strm;
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char *buf;
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struct list_head list;
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};
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static void zlib_free_workspace(struct list_head *ws)
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{
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struct workspace *workspace = list_entry(ws, struct workspace, list);
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vfree(workspace->strm.workspace);
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kfree(workspace->buf);
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kfree(workspace);
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}
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static struct list_head *zlib_alloc_workspace(void)
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{
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struct workspace *workspace;
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int workspacesize;
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workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
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if (!workspace)
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return ERR_PTR(-ENOMEM);
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workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
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zlib_inflate_workspacesize());
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workspace->strm.workspace = vmalloc(workspacesize);
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workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS);
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if (!workspace->strm.workspace || !workspace->buf)
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goto fail;
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INIT_LIST_HEAD(&workspace->list);
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return &workspace->list;
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fail:
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zlib_free_workspace(&workspace->list);
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return ERR_PTR(-ENOMEM);
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}
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static int zlib_compress_pages(struct list_head *ws,
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struct address_space *mapping,
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u64 start, unsigned long len,
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struct page **pages,
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unsigned long nr_dest_pages,
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unsigned long *out_pages,
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unsigned long *total_in,
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unsigned long *total_out,
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unsigned long max_out)
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{
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struct workspace *workspace = list_entry(ws, struct workspace, list);
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int ret;
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char *data_in;
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char *cpage_out;
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int nr_pages = 0;
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struct page *in_page = NULL;
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struct page *out_page = NULL;
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unsigned long bytes_left;
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*out_pages = 0;
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*total_out = 0;
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*total_in = 0;
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if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) {
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printk(KERN_WARNING "BTRFS: deflateInit failed\n");
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ret = -EIO;
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goto out;
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}
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workspace->strm.total_in = 0;
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workspace->strm.total_out = 0;
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in_page = find_get_page(mapping, start >> PAGE_SHIFT);
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data_in = kmap(in_page);
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out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
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if (out_page == NULL) {
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ret = -ENOMEM;
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goto out;
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}
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cpage_out = kmap(out_page);
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pages[0] = out_page;
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nr_pages = 1;
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workspace->strm.next_in = data_in;
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workspace->strm.next_out = cpage_out;
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workspace->strm.avail_out = PAGE_SIZE;
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workspace->strm.avail_in = min(len, PAGE_SIZE);
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while (workspace->strm.total_in < len) {
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ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
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if (ret != Z_OK) {
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printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n",
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ret);
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zlib_deflateEnd(&workspace->strm);
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ret = -EIO;
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goto out;
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}
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/* we're making it bigger, give up */
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if (workspace->strm.total_in > 8192 &&
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workspace->strm.total_in <
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workspace->strm.total_out) {
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ret = -E2BIG;
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goto out;
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}
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/* we need another page for writing out. Test this
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* before the total_in so we will pull in a new page for
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* the stream end if required
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*/
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if (workspace->strm.avail_out == 0) {
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kunmap(out_page);
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if (nr_pages == nr_dest_pages) {
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out_page = NULL;
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ret = -E2BIG;
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goto out;
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}
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out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
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if (out_page == NULL) {
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ret = -ENOMEM;
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goto out;
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}
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cpage_out = kmap(out_page);
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pages[nr_pages] = out_page;
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nr_pages++;
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workspace->strm.avail_out = PAGE_SIZE;
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workspace->strm.next_out = cpage_out;
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}
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/* we're all done */
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if (workspace->strm.total_in >= len)
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break;
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/* we've read in a full page, get a new one */
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if (workspace->strm.avail_in == 0) {
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if (workspace->strm.total_out > max_out)
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break;
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bytes_left = len - workspace->strm.total_in;
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kunmap(in_page);
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put_page(in_page);
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start += PAGE_SIZE;
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in_page = find_get_page(mapping,
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start >> PAGE_SHIFT);
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data_in = kmap(in_page);
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workspace->strm.avail_in = min(bytes_left,
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PAGE_SIZE);
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workspace->strm.next_in = data_in;
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}
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}
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workspace->strm.avail_in = 0;
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ret = zlib_deflate(&workspace->strm, Z_FINISH);
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zlib_deflateEnd(&workspace->strm);
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if (ret != Z_STREAM_END) {
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ret = -EIO;
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goto out;
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}
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if (workspace->strm.total_out >= workspace->strm.total_in) {
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ret = -E2BIG;
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goto out;
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}
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ret = 0;
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*total_out = workspace->strm.total_out;
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*total_in = workspace->strm.total_in;
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out:
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*out_pages = nr_pages;
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if (out_page)
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kunmap(out_page);
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if (in_page) {
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kunmap(in_page);
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put_page(in_page);
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}
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return ret;
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}
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static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
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u64 disk_start,
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struct bio_vec *bvec,
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int vcnt,
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size_t srclen)
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{
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struct workspace *workspace = list_entry(ws, struct workspace, list);
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int ret = 0, ret2;
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int wbits = MAX_WBITS;
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char *data_in;
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size_t total_out = 0;
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unsigned long page_in_index = 0;
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unsigned long page_out_index = 0;
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unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
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unsigned long buf_start;
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unsigned long pg_offset;
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data_in = kmap(pages_in[page_in_index]);
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workspace->strm.next_in = data_in;
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workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
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workspace->strm.total_in = 0;
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workspace->strm.total_out = 0;
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workspace->strm.next_out = workspace->buf;
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workspace->strm.avail_out = PAGE_SIZE;
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pg_offset = 0;
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/* If it's deflate, and it's got no preset dictionary, then
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we can tell zlib to skip the adler32 check. */
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if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
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((data_in[0] & 0x0f) == Z_DEFLATED) &&
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!(((data_in[0]<<8) + data_in[1]) % 31)) {
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wbits = -((data_in[0] >> 4) + 8);
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workspace->strm.next_in += 2;
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workspace->strm.avail_in -= 2;
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}
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if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
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printk(KERN_WARNING "BTRFS: inflateInit failed\n");
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return -EIO;
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}
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while (workspace->strm.total_in < srclen) {
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ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
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if (ret != Z_OK && ret != Z_STREAM_END)
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break;
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buf_start = total_out;
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total_out = workspace->strm.total_out;
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/* we didn't make progress in this inflate call, we're done */
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if (buf_start == total_out)
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break;
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ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
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total_out, disk_start,
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bvec, vcnt,
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&page_out_index, &pg_offset);
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if (ret2 == 0) {
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ret = 0;
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goto done;
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}
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workspace->strm.next_out = workspace->buf;
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workspace->strm.avail_out = PAGE_SIZE;
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if (workspace->strm.avail_in == 0) {
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unsigned long tmp;
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kunmap(pages_in[page_in_index]);
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page_in_index++;
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if (page_in_index >= total_pages_in) {
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data_in = NULL;
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break;
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}
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data_in = kmap(pages_in[page_in_index]);
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workspace->strm.next_in = data_in;
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tmp = srclen - workspace->strm.total_in;
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workspace->strm.avail_in = min(tmp,
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PAGE_SIZE);
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}
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}
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if (ret != Z_STREAM_END)
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ret = -EIO;
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else
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ret = 0;
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done:
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zlib_inflateEnd(&workspace->strm);
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if (data_in)
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kunmap(pages_in[page_in_index]);
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if (!ret)
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btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset);
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return ret;
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}
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static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
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struct page *dest_page,
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unsigned long start_byte,
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size_t srclen, size_t destlen)
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{
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struct workspace *workspace = list_entry(ws, struct workspace, list);
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int ret = 0;
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int wbits = MAX_WBITS;
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unsigned long bytes_left;
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unsigned long total_out = 0;
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unsigned long pg_offset = 0;
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char *kaddr;
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destlen = min_t(unsigned long, destlen, PAGE_SIZE);
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bytes_left = destlen;
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workspace->strm.next_in = data_in;
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workspace->strm.avail_in = srclen;
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workspace->strm.total_in = 0;
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workspace->strm.next_out = workspace->buf;
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workspace->strm.avail_out = PAGE_SIZE;
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workspace->strm.total_out = 0;
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/* If it's deflate, and it's got no preset dictionary, then
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we can tell zlib to skip the adler32 check. */
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if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
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((data_in[0] & 0x0f) == Z_DEFLATED) &&
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!(((data_in[0]<<8) + data_in[1]) % 31)) {
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wbits = -((data_in[0] >> 4) + 8);
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workspace->strm.next_in += 2;
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workspace->strm.avail_in -= 2;
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}
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if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
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printk(KERN_WARNING "BTRFS: inflateInit failed\n");
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return -EIO;
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}
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while (bytes_left > 0) {
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unsigned long buf_start;
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unsigned long buf_offset;
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unsigned long bytes;
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ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
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if (ret != Z_OK && ret != Z_STREAM_END)
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break;
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buf_start = total_out;
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total_out = workspace->strm.total_out;
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if (total_out == buf_start) {
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ret = -EIO;
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break;
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}
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if (total_out <= start_byte)
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goto next;
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if (total_out > start_byte && buf_start < start_byte)
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buf_offset = start_byte - buf_start;
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else
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buf_offset = 0;
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bytes = min(PAGE_SIZE - pg_offset,
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PAGE_SIZE - buf_offset);
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bytes = min(bytes, bytes_left);
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kaddr = kmap_atomic(dest_page);
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memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
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kunmap_atomic(kaddr);
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pg_offset += bytes;
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bytes_left -= bytes;
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next:
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workspace->strm.next_out = workspace->buf;
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workspace->strm.avail_out = PAGE_SIZE;
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}
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if (ret != Z_STREAM_END && bytes_left != 0)
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ret = -EIO;
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else
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ret = 0;
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zlib_inflateEnd(&workspace->strm);
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/*
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* this should only happen if zlib returned fewer bytes than we
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* expected. btrfs_get_block is responsible for zeroing from the
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* end of the inline extent (destlen) to the end of the page
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*/
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if (pg_offset < destlen) {
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kaddr = kmap_atomic(dest_page);
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memset(kaddr + pg_offset, 0, destlen - pg_offset);
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kunmap_atomic(kaddr);
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}
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return ret;
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}
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const struct btrfs_compress_op btrfs_zlib_compress = {
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.alloc_workspace = zlib_alloc_workspace,
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.free_workspace = zlib_free_workspace,
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.compress_pages = zlib_compress_pages,
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.decompress_biovec = zlib_decompress_biovec,
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.decompress = zlib_decompress,
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};
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