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d397712bcc
There were many, most are fixed now. struct-funcs.c generates some warnings but these are bogus. Signed-off-by: Chris Mason <chris.mason@oracle.com>
633 lines
16 KiB
C
633 lines
16 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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/* Plan: call deflate() with avail_in == *sourcelen,
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avail_out = *dstlen - 12 and flush == Z_FINISH.
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If it doesn't manage to finish, call it again with
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avail_in == 0 and avail_out set to the remaining 12
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bytes for it to clean up.
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Q: Is 12 bytes sufficient?
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*/
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#define STREAM_END_SPACE 12
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struct workspace {
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z_stream inf_strm;
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z_stream def_strm;
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char *buf;
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struct list_head list;
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};
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static LIST_HEAD(idle_workspace);
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static DEFINE_SPINLOCK(workspace_lock);
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static unsigned long num_workspace;
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static atomic_t alloc_workspace = ATOMIC_INIT(0);
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static DECLARE_WAIT_QUEUE_HEAD(workspace_wait);
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/*
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* this finds an available zlib workspace or allocates a new one
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* NULL or an ERR_PTR is returned if things go bad.
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*/
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static struct workspace *find_zlib_workspace(void)
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{
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struct workspace *workspace;
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int ret;
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int cpus = num_online_cpus();
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again:
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spin_lock(&workspace_lock);
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if (!list_empty(&idle_workspace)) {
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workspace = list_entry(idle_workspace.next, struct workspace,
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list);
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list_del(&workspace->list);
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num_workspace--;
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spin_unlock(&workspace_lock);
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return workspace;
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}
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spin_unlock(&workspace_lock);
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if (atomic_read(&alloc_workspace) > cpus) {
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DEFINE_WAIT(wait);
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prepare_to_wait(&workspace_wait, &wait, TASK_UNINTERRUPTIBLE);
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if (atomic_read(&alloc_workspace) > cpus)
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schedule();
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finish_wait(&workspace_wait, &wait);
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goto again;
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}
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atomic_inc(&alloc_workspace);
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workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
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if (!workspace) {
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ret = -ENOMEM;
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goto fail;
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}
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workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
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if (!workspace->def_strm.workspace) {
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ret = -ENOMEM;
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goto fail;
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}
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workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
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if (!workspace->inf_strm.workspace) {
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ret = -ENOMEM;
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goto fail_inflate;
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}
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workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
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if (!workspace->buf) {
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ret = -ENOMEM;
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goto fail_kmalloc;
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}
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return workspace;
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fail_kmalloc:
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vfree(workspace->inf_strm.workspace);
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fail_inflate:
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vfree(workspace->def_strm.workspace);
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fail:
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kfree(workspace);
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atomic_dec(&alloc_workspace);
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wake_up(&workspace_wait);
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return ERR_PTR(ret);
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}
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/*
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* put a workspace struct back on the list or free it if we have enough
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* idle ones sitting around
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*/
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static int free_workspace(struct workspace *workspace)
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{
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spin_lock(&workspace_lock);
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if (num_workspace < num_online_cpus()) {
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list_add_tail(&workspace->list, &idle_workspace);
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num_workspace++;
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spin_unlock(&workspace_lock);
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if (waitqueue_active(&workspace_wait))
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wake_up(&workspace_wait);
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return 0;
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}
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spin_unlock(&workspace_lock);
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vfree(workspace->def_strm.workspace);
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vfree(workspace->inf_strm.workspace);
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kfree(workspace->buf);
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kfree(workspace);
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atomic_dec(&alloc_workspace);
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if (waitqueue_active(&workspace_wait))
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wake_up(&workspace_wait);
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return 0;
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}
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/*
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* cleanup function for module exit
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*/
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static void free_workspaces(void)
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{
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struct workspace *workspace;
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while (!list_empty(&idle_workspace)) {
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workspace = list_entry(idle_workspace.next, struct workspace,
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list);
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list_del(&workspace->list);
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vfree(workspace->def_strm.workspace);
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vfree(workspace->inf_strm.workspace);
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kfree(workspace->buf);
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kfree(workspace);
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atomic_dec(&alloc_workspace);
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}
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}
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/*
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* given an address space and start/len, compress the bytes.
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*
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* pages are allocated to hold the compressed result and stored
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* in 'pages'
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*
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* out_pages is used to return the number of pages allocated. There
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* may be pages allocated even if we return an error
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*
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* total_in is used to return the number of bytes actually read. It
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* may be smaller then len if we had to exit early because we
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* ran out of room in the pages array or because we cross the
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* max_out threshold.
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*
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* total_out is used to return the total number of compressed bytes
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*
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* max_out tells us the max number of bytes that we're allowed to
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* stuff into pages
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*/
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int btrfs_zlib_compress_pages(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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int ret;
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struct workspace *workspace;
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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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int out_written = 0;
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int in_read = 0;
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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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workspace = find_zlib_workspace();
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if (!workspace)
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return -1;
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if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
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printk(KERN_WARNING "deflateInit failed\n");
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ret = -1;
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goto out;
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}
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workspace->def_strm.total_in = 0;
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workspace->def_strm.total_out = 0;
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in_page = find_get_page(mapping, start >> PAGE_CACHE_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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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->def_strm.next_in = data_in;
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workspace->def_strm.next_out = cpage_out;
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workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
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workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);
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out_written = 0;
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in_read = 0;
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while (workspace->def_strm.total_in < len) {
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ret = zlib_deflate(&workspace->def_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->def_strm);
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ret = -1;
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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->def_strm.total_in > 8192 &&
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workspace->def_strm.total_in <
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workspace->def_strm.total_out) {
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ret = -1;
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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->def_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 = -1;
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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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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->def_strm.avail_out = PAGE_CACHE_SIZE;
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workspace->def_strm.next_out = cpage_out;
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}
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/* we're all done */
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if (workspace->def_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->def_strm.avail_in == 0) {
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if (workspace->def_strm.total_out > max_out)
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break;
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bytes_left = len - workspace->def_strm.total_in;
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kunmap(in_page);
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page_cache_release(in_page);
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start += PAGE_CACHE_SIZE;
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in_page = find_get_page(mapping,
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start >> PAGE_CACHE_SHIFT);
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data_in = kmap(in_page);
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workspace->def_strm.avail_in = min(bytes_left,
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PAGE_CACHE_SIZE);
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workspace->def_strm.next_in = data_in;
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}
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}
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workspace->def_strm.avail_in = 0;
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ret = zlib_deflate(&workspace->def_strm, Z_FINISH);
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zlib_deflateEnd(&workspace->def_strm);
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if (ret != Z_STREAM_END) {
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ret = -1;
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goto out;
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}
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if (workspace->def_strm.total_out >= workspace->def_strm.total_in) {
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ret = -1;
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goto out;
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}
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ret = 0;
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*total_out = workspace->def_strm.total_out;
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*total_in = workspace->def_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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page_cache_release(in_page);
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}
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free_workspace(workspace);
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return ret;
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}
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/*
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* pages_in is an array of pages with compressed data.
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*
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* disk_start is the starting logical offset of this array in the file
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*
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* bvec is a bio_vec of pages from the file that we want to decompress into
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*
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* vcnt is the count of pages in the biovec
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*
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* srclen is the number of bytes in pages_in
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*
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* The basic idea is that we have a bio that was created by readpages.
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* The pages in the bio are for the uncompressed data, and they may not
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* be contiguous. They all correspond to the range of bytes covered by
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* the compressed extent.
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*/
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int btrfs_zlib_decompress_biovec(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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int ret = 0;
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int wbits = MAX_WBITS;
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struct workspace *workspace;
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char *data_in;
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size_t total_out = 0;
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unsigned long page_bytes_left;
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unsigned long page_in_index = 0;
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unsigned long page_out_index = 0;
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struct page *page_out;
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unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
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PAGE_CACHE_SIZE;
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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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unsigned long working_bytes;
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unsigned long pg_offset;
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unsigned long start_byte;
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unsigned long current_buf_start;
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char *kaddr;
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workspace = find_zlib_workspace();
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if (!workspace)
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return -ENOMEM;
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data_in = kmap(pages_in[page_in_index]);
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workspace->inf_strm.next_in = data_in;
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workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
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workspace->inf_strm.total_in = 0;
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workspace->inf_strm.total_out = 0;
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workspace->inf_strm.next_out = workspace->buf;
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workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
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page_out = bvec[page_out_index].bv_page;
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page_bytes_left = PAGE_CACHE_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->inf_strm.next_in += 2;
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workspace->inf_strm.avail_in -= 2;
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}
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if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
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printk(KERN_WARNING "inflateInit failed\n");
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ret = -1;
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goto out;
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}
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while (workspace->inf_strm.total_in < srclen) {
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ret = zlib_inflate(&workspace->inf_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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/*
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* buf start is the byte offset we're of the start of
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* our workspace buffer
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*/
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buf_start = total_out;
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/* total_out is the last byte of the workspace buffer */
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total_out = workspace->inf_strm.total_out;
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working_bytes = total_out - buf_start;
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/*
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* start byte is the first byte of the page we're currently
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* copying into relative to the start of the compressed data.
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*/
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start_byte = page_offset(page_out) - disk_start;
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if (working_bytes == 0) {
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/* we didn't make progress in this inflate
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* call, we're done
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*/
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if (ret != Z_STREAM_END)
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ret = -1;
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break;
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}
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/* we haven't yet hit data corresponding to this page */
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if (total_out <= start_byte)
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goto next;
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/*
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* the start of the data we care about is offset into
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* the middle of our working buffer
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*/
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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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working_bytes -= buf_offset;
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} else {
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buf_offset = 0;
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}
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current_buf_start = buf_start;
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/* copy bytes from the working buffer into the pages */
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while (working_bytes > 0) {
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bytes = min(PAGE_CACHE_SIZE - pg_offset,
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PAGE_CACHE_SIZE - buf_offset);
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bytes = min(bytes, working_bytes);
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kaddr = kmap_atomic(page_out, KM_USER0);
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memcpy(kaddr + pg_offset, workspace->buf + buf_offset,
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bytes);
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kunmap_atomic(kaddr, KM_USER0);
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flush_dcache_page(page_out);
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pg_offset += bytes;
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page_bytes_left -= bytes;
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buf_offset += bytes;
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working_bytes -= bytes;
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current_buf_start += bytes;
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/* check if we need to pick another page */
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if (page_bytes_left == 0) {
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page_out_index++;
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if (page_out_index >= vcnt) {
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ret = 0;
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goto done;
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}
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page_out = bvec[page_out_index].bv_page;
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pg_offset = 0;
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page_bytes_left = PAGE_CACHE_SIZE;
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start_byte = page_offset(page_out) - disk_start;
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/*
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* make sure our new page is covered by this
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* working buffer
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*/
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if (total_out <= start_byte)
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goto next;
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/* the next page in the biovec might not
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* be adjacent to the last page, but it
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* might still be found inside this working
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* buffer. bump our offset pointer
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*/
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if (total_out > start_byte &&
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current_buf_start < start_byte) {
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buf_offset = start_byte - buf_start;
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working_bytes = total_out - start_byte;
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current_buf_start = buf_start +
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buf_offset;
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}
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}
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}
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next:
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workspace->inf_strm.next_out = workspace->buf;
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workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
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if (workspace->inf_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]);
|
|
workspace->inf_strm.next_in = data_in;
|
|
tmp = srclen - workspace->inf_strm.total_in;
|
|
workspace->inf_strm.avail_in = min(tmp,
|
|
PAGE_CACHE_SIZE);
|
|
}
|
|
}
|
|
if (ret != Z_STREAM_END)
|
|
ret = -1;
|
|
else
|
|
ret = 0;
|
|
done:
|
|
zlib_inflateEnd(&workspace->inf_strm);
|
|
if (data_in)
|
|
kunmap(pages_in[page_in_index]);
|
|
out:
|
|
free_workspace(workspace);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* a less complex decompression routine. Our compressed data fits in a
|
|
* single page, and we want to read a single page out of it.
|
|
* start_byte tells us the offset into the compressed data we're interested in
|
|
*/
|
|
int btrfs_zlib_decompress(unsigned char *data_in,
|
|
struct page *dest_page,
|
|
unsigned long start_byte,
|
|
size_t srclen, size_t destlen)
|
|
{
|
|
int ret = 0;
|
|
int wbits = MAX_WBITS;
|
|
struct workspace *workspace;
|
|
unsigned long bytes_left = destlen;
|
|
unsigned long total_out = 0;
|
|
char *kaddr;
|
|
|
|
if (destlen > PAGE_CACHE_SIZE)
|
|
return -ENOMEM;
|
|
|
|
workspace = find_zlib_workspace();
|
|
if (!workspace)
|
|
return -ENOMEM;
|
|
|
|
workspace->inf_strm.next_in = data_in;
|
|
workspace->inf_strm.avail_in = srclen;
|
|
workspace->inf_strm.total_in = 0;
|
|
|
|
workspace->inf_strm.next_out = workspace->buf;
|
|
workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
|
|
workspace->inf_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->inf_strm.next_in += 2;
|
|
workspace->inf_strm.avail_in -= 2;
|
|
}
|
|
|
|
if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
|
|
printk(KERN_WARNING "inflateInit failed\n");
|
|
ret = -1;
|
|
goto out;
|
|
}
|
|
|
|
while (bytes_left > 0) {
|
|
unsigned long buf_start;
|
|
unsigned long buf_offset;
|
|
unsigned long bytes;
|
|
unsigned long pg_offset = 0;
|
|
|
|
ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
|
|
if (ret != Z_OK && ret != Z_STREAM_END)
|
|
break;
|
|
|
|
buf_start = total_out;
|
|
total_out = workspace->inf_strm.total_out;
|
|
|
|
if (total_out == buf_start) {
|
|
ret = -1;
|
|
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, KM_USER0);
|
|
memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
|
|
kunmap_atomic(kaddr, KM_USER0);
|
|
|
|
pg_offset += bytes;
|
|
bytes_left -= bytes;
|
|
next:
|
|
workspace->inf_strm.next_out = workspace->buf;
|
|
workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
|
|
}
|
|
|
|
if (ret != Z_STREAM_END && bytes_left != 0)
|
|
ret = -1;
|
|
else
|
|
ret = 0;
|
|
|
|
zlib_inflateEnd(&workspace->inf_strm);
|
|
out:
|
|
free_workspace(workspace);
|
|
return ret;
|
|
}
|
|
|
|
void btrfs_zlib_exit(void)
|
|
{
|
|
free_workspaces();
|
|
}
|