From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- fs/btrfs/zlib.c | 412 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 412 insertions(+) create mode 100644 fs/btrfs/zlib.c (limited to 'fs/btrfs/zlib.c') 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 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#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, +}; -- cgit v1.2.3